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71.
The Trivers–Willard hypothesis predicts sex biases in parental investment according to parental condition. In addition, parents may need to sex bias their investment if there is an asymmetry between the sexes in offspring fitness under different conditions. For studying maternal differential investment, egg resources are ideal subjects because they are self contained and allocated unequivocally by the female. Recent studies show that yolk androgens can be beneficial to offspring, so here we test for sex-biased investment with maternal investment of yolk testosterone (T) in zebra finch (Taeniopygia guttata) eggs. From the Trivers–Willard hypothesis, we predicted females to invest more in male eggs in optimum circumstances (e.g. good-condition mother, early-laid egg), and more in female eggs under suboptimal conditions (e.g. poor-condition mother, late-laid egg). This latter prediction is also because in this species there is a female nestling disadvantage in poor conditions and we expected mothers to help compensate for this in female eggs. Indeed, we found more yolk T in female than male eggs. Moreover, in accordance with our predictions, yolk T in male eggs increased with maternal quality relative to female eggs, and decreased with laying order relative to female eggs. This supports our predictions for the different needs and value of male and female offspring in zebra finches. Our results support the idea that females may use yolk androgens as a tool to adaptively manipulate the inequalities between different nestlings. 相似文献
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BackgroundThere is an enhanced international awareness that the improper disposal of unwanted and unused medications may have a detrimental effect on the environment.ObjectivesThe aim of this study was to determine the proportion of unused medications in New Zealand that are not returned to a pharmacy for disposal and are instead disposed of via land fill or water systems. In addition, this study intended to identify why these medications were unused or unwanted.DesignAn online survey was placed on the New Zealand National Poisons Centre website for a period of three months during 2008. This consisted of a series of questions with predefined answer sets and asked about collection of medications, why there may be unused medications, storage of medications and disposal of medications.ResultsThis survey was completed by 452 individuals. 62% of respondents currently had unwanted medications in their house. The most common reason for people to have leftover medication was ‘medical condition improved or resolved’ (n = 307). Depending on formulation type, between 13–24% of unused medications were returned to pharmacies with tablets and capsules being most likely to be returned and liquids most likely to be added to water systems.ConclusionsA significant percentage of unwanted medications are disposed of via routes that have the potential to adversely affect the environment. Reducing excess medications and wastage as well as education of appropriate disposal techniques may minimize their potential impact on the environment. 相似文献
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This paper reports a meta-analysis of studies using the New Environmental Paradigm (NEP) Scale over the last 30 years. A review of 69 studies from 36 countries (including 58,279 participants from 139 samples) shows that there is considerable variation in the way the NEP Scale is used, particularly with regards to the number of items used and the number of points on the Likert scale employed. Results from weighted regression analyses reveals that variations in sample type and scale length have a significant effect on NEP scores. In particular, environmentalist and white-collar samples scored significantly higher on the NEP Scale than nationally or regionally representative samples, while blue-collar samples scored significantly lower; and participants scored higher on 6-item versions of the scale than on the revised 15-item version, and lower on versions of the scale containing 5, 7, 8 or 10 items. Implications of this research for the comparability of previous studies using the NEP Scale are discussed and guidelines for future research are presented. 相似文献
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Direct and indirect effects of ammonia, ammonium and nitrate on phosphatase activity and carbon fluxes from decomposing litter in peatland 总被引:1,自引:0,他引:1
David Johnson Lucy Moore Ian D. Leith 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3157-3163
Here we investigate the response of soils and litter to 5 years of experimental additions of ammonium (NH4), nitrate (NO3), and ammonia (NH3) to an ombrotrophic peatland. We test the importance of direct (via soil) and indirect (via litter) effects on phosphatase activity and efflux of CO2. We also determined how species representing different functional types responded to the nitrogen treatments. Our results demonstrate that additions of NO3, NH4 and NH3 all stimulated phosphatase activity but the effects were dependent on species of litter and mechanism (direct or indirect). Deposition of NH3 had no effect on efflux of CO2 from Calluna vulgaris litter, despite it showing signs of stress in the field, whereas both NO3 and NH4 reduced CO2 fluxes. Our results show that the collective impacts on peatlands of the three principal forms of nitrogen in atmospheric deposition are a result of differential effects and mechanisms on individual components. 相似文献
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The identification of cell-free fetal DNA circulating in maternal blood combined with technological developments, in particular next-generation sequencing, is enabling the development of safer prenatal diagnosis. While this technology has been widely applied as a highly sensitive screening test for aneuploidy, there has been relatively little clinical application for the diagnosis of monogenic disorders. In the UK, we have established non-invasive prenatal diagnosis (NIPD) as a clinical service for a range of inherited disorders. The results from NIPD do not require confirmation by invasive testing and are welcomed by patients and health professionals alike. Here, we describe the technical approaches used, current practice and outline recommendations for best practice when delivering an NIPD service from an accredited laboratory. © 2017 John Wiley & Sons, Ltd. 相似文献
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