523 research outputs found

    CO2 and non-CO2 radiative forcings in climate projections for twenty-first century mitigation scenarios

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    Climate is simulated for reference and mitigation emissions scenarios from Integrated Assessment Models using the Bern2.5CC carbon cycle-climate model. Mitigation options encompass all major radiative forcing agents. Temperature change is attributed to forcings using an impulse-response substitute of Bern2.5CC. The contribution of CO2 to global warming increases over the century in all scenarios. Non-CO2 mitigation measures add to the abatement of global warming. The share of mitigation carried by CO2, however, increases when radiative forcing targets are lowered, and increases after 2000 in all mitigation scenarios. Thus, non-CO2 mitigation is limited and net CO2 emissions must eventually subside. Mitigation rapidly reduces the sulfate aerosol loading and associated cooling, partly masking Greenhouse Gas mitigation over the coming decades. A profound effect of mitigation on CO2 concentration, radiative forcing, temperatures and the rate of climate change emerges in the second half of the centur

    Nationwide indoor smoking ban and impact on smoking behaviour and lung function: a two-population natural experiment

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    INTRODUCTION Many countries have implemented indoor smoking bans over the past two decades. Although smoking bans have been shown to reduce cardiovascular outcomes, little is known about their impact on respiratory health. This study investigated the impact of a nationwide indoor smoking ban on smoking behaviour and lung function. METHODS We used repeated cross-sectional data from two large cohorts of the general population comprising 31 807 Swiss and 62 093 Danish adults. We compared associations between smoking ban and smoking prevalence and prebronchodilator lung function trends in Denmark (indoor smoking ban introduced in 2007) and Switzerland (indoor smoking ban introduced in 2010) from 2005 to 2010 using a quasi-experimental study design. We performed difference-in-difference analyses with linear regression models adjusted for age, sex, weight and height. RESULTS Denmark had a stronger decrease in active smokers compared with Switzerland. Also, forced expiratory volume in the first second was higher in Danish adults than in Swiss adults: 26 mL (95% CI 2.4 to 49) 1 year, 88 mL (65 to 112) 2 years, and 74 mL (51 to 98) 3 years after smoking ban implementation. Correspondingly, forced vital capacity was higher in Danish adults compared with Swiss adults (80 mL (50 to 109) after 1 year and 126 mL (97 to 155) after two and 3 years). Improvements were observed in both never-smokers and ever-smokers, most pronounced in ever-smokers. CONCLUSIONS Nationwide indoor smoking ban is associated with less smoking and improved lung function in the general population. Implementing an indoor smoking ban can improve lung function by influencing smoking behaviour and reducing secondhand smoke

    Marketing Authorization Applications Made to the European Medicines Agency in 2018-2019:What was the Contribution of Real-World Evidence?

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    Information derived from routinely collected real-world data has for a long time been used to support regulatory decision making on the safety of drugs and has more recently been used to support marketing authorization submissions to regulators. There is a lack of detailed information on the use and types of this real-world evidence (RWE) as submitted to regulators. We used resources held by the European Medicines Agency (EMA) to describe the characteristics of RWE included in new marketing authorization applications (MAAs) and extensions of indication (EOIs) for already authorized products submitted to the EMA in 2018 and 2019. For MAAs, 63 of 158 products (39.9%) contained RWE with a total of 117 studies. For 31.7% of these products, the RWE submitted was derived from data collected before the planned authorization. The most common data sources were registries (60.3%) followed by hospital data (31.7%). RWE was mainly included to support safety (87.3%) and efficacy (49.2%) with cohort studies being the most frequently used study design (88.9%). For EOIs, 28 of 153 products (18.3%) contained RWE with a total of 36 studies. For 57.1% of these products, studies were conducted prior to the EOIs. RWE sources were mainly registries (35.6%) and hospital data (27.0%). RWE was typically used to support safety (82.1%) and efficacy (53.6%). Cohort studies were the most commonly used study design (87.6%). We conclude that there is widespread use of RWE to support evaluation of MAAs and EOIs submitted to the EMA and identify areas where further research is required

    Segregate or cooperate- a study of the interaction between two species of Dictyostelium

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    <p>Abstract</p> <p>Background</p> <p>A major challenge for evolutionary biology is explaining altruism, particularly when it involves death of one party and occurs across species. Chimeric fruiting bodies of <it>Dictyostelium discoideum </it>and <it>Dictyostelium purpureum </it>develop from formerly independent amoebae, and some die to help others. Here we examine co-aggregation between <it>D. discoideum </it>and <it>D. purpureum</it>, determine its frequency and which party benefits, and the extent of fair play in contribution to the altruistic caste.</p> <p>Results</p> <p>We mixed cells from both species in equal proportions, and then we analyzed 198 individual fruiting bodies, which always had either a <it>D. discoideum </it>or <it>D. purpureum </it>phenotype (<it>D. discoideum</it>- 98, <it>D. purpureum</it>- 100). Fifty percent of the fruiting bodies that looked like <it>D. discoideum </it>and 22% of the fruiting bodies that looked like <it>D. purpureum </it>were chimeric, though the majority of spores in any given fruiting body belonged to one species (<it>D. discoideum </it>fruiting bodies- 0.85 ± 0.03, <it>D. purpureum </it>fruiting bodies- 0.94 ± 0.02). Clearly, there is species level recognition occurring that keeps the cells mostly separate. The number of fruiting bodies produced with the <it>D. discoideum </it>phenotype increased from 225 ± 32 fruiting bodies when <it>D. discoideum </it>was alone to 486 ± 61 in the mix treatments. However, the number of <it>D. discoideum </it>spores decreased, although not significantly, from 2.75e<sup>7 </sup>± 1.29e<sup>7 </sup>spores in the controls to 2.06e<sup>7 </sup>± 8.33e<sup>6 </sup>spores in the mix treatments. <it>D. purpureum </it>fruiting body and spore production decreased from 719 ± 111 fruiting bodies and 5.81e<sup>7 </sup>± 1.26e<sup>7 </sup>spores in the controls to 394 ± 111 fruiting bodies and 9.75e<sup>6 </sup>± 2.25e<sup>6 </sup>spores in the mix treatments.</p> <p>Conclusion</p> <p>Both species appear to favor clonality but can cooperate with each other to produce fruiting bodies. Cooperating amoebae are able to make larger fruiting bodies, which are advantageous for migration and dispersal, but both species here suffer a cost in producing fewer spores per fruiting body.</p

    Tumour inoculation site-dependent induction of cachexia in mice bearing colon 26 carcinoma

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    Murine colon 26 carcinoma growing at either subcutaneous (s.c.) or intramuscular (i.m.) inoculation sites causes cachexia in mice. Such animals show extensive loss of body weight, wasting of the muscle and adipose tissues, hypoglycaemia, and hypercalcaemia, even when the tumour weight comprises only about 1.9% of carcass weight. In contrast, the same tumour when inoculated into the liver does not cause any sign of tumour-related cachexia even when the tumour becomes much larger (6.6% of carcass weight). Interleukin 6 (IL-6), a mediator associated with cachexia in this tumour model, is detected at high levels both in the tumour tissues and in the circulating blood of mice bearing colon 26 tumour at the s.c. inoculation site. In contrast, only minute levels of IL-6 are detected in the tumour grown in the liver. The colon 26 tumour grown in the liver does not lose its ability to cause cachexia, because the tumour when re-inoculated s.c. is able to cause extensive weight loss and produce IL-6 as did the original colon 26 cell line. Histological studies revealed differences in the composition of tumour tissues: the tumours grown in the subcutis consist of many polygonal tumour cells, extended-intercellular space, and high vascular density, whereas those grown in the liver consist of spindle-shaped tumour cells. Thus, the environment where tumour cells grow would be a critical factor in determining the cachectic phenotype of cancer cells, including their ability to produce IL-6. 1999 Cancer Research Campaig

    Anarchy in the UK: Detailed genetic analysis of worker reproduction in a naturally occurring British anarchistic honeybee, Apis mellifera, colony using DNA microsatellites

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    Anarchistic behaviour is a very rare phenotype of honeybee colonies. In an anarchistic colony, many workers’ sons are reared in the presence of the queen. Anarchy has previously been described in only two Australian colonies. Here we report on a first detailed genetic analysis of a British anarchistic colony. Male pupae were present in great abundance above the queen excluder, which was clearly indicative of extensive worker reproduction and is the hallmark of anarchy. Seventeen microsatellite loci were used to analyse these male pupae, allowing us to address whether all the males were indeed workers’ sons, and how many worker patrilines and individual workers produced them. In the sample, 95 of 96 of the males were definitely workers’ sons. Given that ≈ 1% of workers’ sons were genetically indistinguishable from queen’s sons, this suggests that workers do not move any queen-laid eggs between the part of the colony where the queen is present to the area above the queen excluder which the queen cannot enter. The colony had 16 patrilines, with an effective number of patrilines of 9.85. The 75 males that could be assigned with certainty to a patriline came from 7 patrilines, with an effective number of 4.21. They were the offspring of at least 19 workers. This is in contrast to the two previously studied Australian naturally occurring anarchist colonies, in which most of the workers’ sons were offspring of one patriline. The high number of patrilines producing males leads to a low mean relatedness between laying workers and males of the colony. We discuss the importance of studying such colonies in the understanding of worker policing and its evolution

    Inferring human population sizes, divergence times and rates of gene flow from mitochondrial, X and Y chromosome resequencing data

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    We estimate parameters of a general isolation-with-migration model using resequence data from mitochondrial DNA (mtDNA), the Y chromosome, and two loci on the X chromosome in samples of 25-50 individuals from each of 10 human populations. Application of a coalescent-based Markov chain Monte Carlo technique allows simultaneous inference of divergence times, rates of gene flow, as well as changes in effective population size. Results from comparisons between sub-Saharan African and Eurasian populations estimate that 1500 individuals founded the ancestral Eurasian population similar to 40 thousand years ago (KYA). Furthermore, these small Eurasian founding populations appear to have grown much more dramatically than either African or Oceanian populations. Analyses of sub-Saharan African populations provide little evidence for a history, of population bottlenecks and suggest that die), began diverging from one another upward of 50 KYA. We surmise that ancestral African populations had already been geographically structured prior to the founding of ancestral Eurasian populations. African populations are shown to experience low levels of mitochondrial DNA gene flow, but high levels of Y chromosome gene flow. In particular, Y chromosome gene flow appears to be asymmetric, i.e., from the Bantu-speaking population into other African populations. Conversely, mitochondrial gene flow is more extensive between non-African populations, but appears to be absent between European and Asian Populations

    Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity

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    In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity

    Female economic dependence and the morality of promiscuity

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    This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Author(s) 2014.In environments in which female economic dependence on a male mate is higher, male parental investment is more essential. In such environments, therefore, both sexes should value paternity certainty more and thus object more to promiscuity (because promiscuity undermines paternity certainty). We tested this theory of anti-promiscuity morality in two studies (N = 656 and N = 4,626) using U.S. samples. In both, we examined whether opposition to promiscuity was higher among people who perceived greater female economic dependence in their social network. In Study 2, we also tested whether economic indicators of female economic dependence (e.g., female income, welfare availability) predicted anti-promiscuity morality at the state level. Results from both studies supported the proposed theory. At the individual level, perceived female economic dependence explained significant variance in anti-promiscuity morality, even after controlling for variance explained by age, sex, religiosity, political conservatism, and the anti-promiscuity views of geographical neighbors. At the state level, median female income was strongly negatively related to anti-promiscuity morality and this relationship was fully mediated by perceived female economic dependence. These results were consistent with the view that anti-promiscuity beliefs may function to promote paternity certainty in circumstances where male parental investment is particularly important

    Growth dynamics and the evolution of cooperation in microbial populations

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    Microbes providing public goods are widespread in nature despite running the risk of being exploited by free-riders. However, the precise ecological factors supporting cooperation are still puzzling. Following recent experiments, we consider the role of population growth and the repetitive fragmentation of populations into new colonies mimicking simple microbial life-cycles. Individual-based modeling reveals that demographic fluctuations, which lead to a large variance in the composition of colonies, promote cooperation. Biased by population dynamics these fluctuations result in two qualitatively distinct regimes of robust cooperation under repetitive fragmentation into groups. First, if the level of cooperation exceeds a threshold, cooperators will take over the whole population. Second, cooperators can also emerge from a single mutant leading to a robust coexistence between cooperators and free-riders. We find frequency and size of population bottlenecks, and growth dynamics to be the major ecological factors determining the regimes and thereby the evolutionary pathway towards cooperation.Comment: 26 pages, 6 figure
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