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Meta-analysis reveals that reproductive strategies are associated with sexual differences in oxidative balance across vertebrates

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Current Zoology 2018年第1期64卷 1-11页

作者： david COSTANTINI UMR 7221 Museum National d'Histoire Naturelle 7 rue Cuvier 75231 Paris Cedex 05 France Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Alfred-Kowalke-Str. 17 Berlin 10315 Germany Behavioural Ecology & Ecophysiology Group Department of Biology University of Antwerp Universiteitsplein 1 Wilrijk 2610 Belgium

Oxidative stress is a key physiological mechanism underlying life-history tradeoffs. Here, I use meta-analytic techniques to test whether sexual differences in oxidative balance are common in vertebrates and to identify which factors are associated with such differences. The dataset included 732 effect size estimates from 100 articles （82 species）. Larger unsigned effect size （meaning larger sexual differences in a given marker） occurred in： reptiles and fish; those species that do not pro- vide parental care; and oviparous species. Estimates of signed effect size （positive values meaning higher oxidative stress in males） indicated that females were less resistant to oxidative stress than males in： reptiles while males and females were similar in fish, birds, and mammals; those species that do not provide parental care; and oviparous species. There was no evidence for a significant sexual differentiation in oxidative balance in fish, birds, and mammals. Effect size was not associ- ated with： the number of offspring; whether the experimental animals were reproducing or not; biomarker （oxidative damage, non-enzymatic, or enzymatic antioxidant）, the species body mass; the strain （wild vs. domestic）; or the study environment （wild vs. captivity）. Oxidative stress tended to be higher in females than males across most of the tissues analyzed. Levels of residual heterogeneity were high in all models tested. The findings of this meta-analysis indicate that diversification of reproductive strategies might be associated with sexual differences in oxidative balance. This explorative meta-analysis offers a starting platform for future research to investigate the rela-tionship between sex and oxidative balance further.

关键词： antioxidants oviparity oxidative damage parental care vertebrates viviparity.

Transitioning from paternalism to empowerment of farmers in lowincome countries: Farming components to systems

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Journal of Integrative Agriculture 2015年第8期14卷 1490-1499页

作者： david Norman Agricultural Economics Department Kansas State University

Reasons for the initiation of farming systems/participatory approaches in non-Green Revolution（i.e., in more heterogeneous and less favourable production environments） areas in low-income countries is followed by a discussion of their *** phases are described along, with a brief description of some of the significant methods in which farmer participation has been sought, accessed and *** enabled/facilitated the evolutionary ***, over the last 40 years there has been a progress in making small-scale farmers much more visible in driving the agricultural research/development agenda through using the four basic stages embodied in the farming systems approach（i.e., descriptive, diagnosis, testing/evaluation and finally dissemination）, much still needs to be *** leads on to a discussion as to some of the barriers still inhibiting true farmer empowerment and why further, such empowerment is imperative, if the agricultural challenges of this century are to be addressed successfully, namely substantially increasing agricultural productivity in an ecologically sustainable *** the heterogeneity of the production environments and that many identified improvements are likely to be incremental rather than revolutionary in nature, this will require farmers＇ intimate involvement in their identification, evaluation and *** in the paper recognizes that there is increasing globalization/commercialization of agriculture and is predicated on the need to consider the whole farmer-research-development continuum involving multiple stakeholders（i.e., farmers, scientists, extension workers, input/output service providers and policymakers）.Such a continuum has been explicitly recognized in the operational plans for the recently reformed international agricultural research（i.e., CGIAR） *** paper concludes with a short discussion on the potential role of formal modelling.

关键词： farming systems research farmer empowerment farmer participatory approaches/techniques globalisation commercialisation conservat

The genetic architecture of autism spectrum disorders(ASDs) and the potential importance of common regulatory genetic variants

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Science China(Life Sciences) 2015年第10期58卷 968-975页

作者： david SAFFEN Institutes of Brain Science Fudan University

Currently, there is great interest in identifying genetic variants that contribute to the risk of developing autism spectrum disor- ders （ASDs）, due in part to recent increases in the frequency of diagnosis of these disorders worldwide. While there is nearly universal agreement that ASDs are complex diseases, with multiple genetic and environmental contributing factors, there is less agreement concerning the relative importance of common vs rare genetic variants in ASD liability. Recent observations that rare mutations and copy number variants （CNVs） are frequently associated with ASDs, combined with reduced fecundity of individuals with these disorders, has led to the hypothesis that ASDs are caused primarily by de novo or rare genetic muta- tions. Based on this model, large-scale whole-genome DNA sequencing has been proposed as the most appropriate method for discovering ASD liability genes. While this approach will undoubtedly identity many novel candidate genes and produce important new insights concerning the genetic causes of these disorders, a full accounting of the genetics of ASDs will be incomplete absent an understanding of the contributions of common regulatory variants, which are likely to influence ASD liability by modifying the effects of rare variants or, by assuming unfavorable combinations, directly produce these disorders. Because it is not yet possible to identify regulatory genetic variants by examination of DNA sequences alone, their identitication will require experimentation. In this essay, I discuss these issues and describe the advantages of measurements of allelic expression imbalance （AEI） of mRNA expression for identifying cis-acting regulatory variants that contribute to ASDs.

关键词： common-disease-common-variant model common-disease-rare-variant model copy number variant (CNV) aUelic expression imbalance (AEI)

One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

Volcanic Ash in the Atmosphere and Risks for Civil Aviation:A Study in European Crisis Management

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International Journal of Disaster Risk Science 2013年第1期4卷 9-19页

作者： david Alexander Institute for Risk and Disaster Reduction University College London London WC1E 6BT United Kingdom

This paper uses the eruption of the Icelandic volcano Eyjafjallaj?kull in April and May 2010 as a case study of disruption to civil aviation by airborne ash, with emphasis on risk management aspects. Severe curtailment of flights over much of Europe took place during the crisis, which lasted for slightly more than one week. More than 8.5 million passengers were stranded and commerce was profoundly affected. The United Kingdom was one of the worst impacted countries and took the lead in managing the crisis. The paper considers elements of the decision-making process that formed the basis of the UK Government’s emergency response. It examines the relations between science, governance, and economi c imperatives. Physical thresholds guiding decisions to restrict airspace were defined somewhat arbitrarily, which may have increased disruption. A damaging form of risk aversion prevailed at certain points in the crisis. Lack of preexisting procedures and planning meant that the response to dynamically changing meteorological conditions had to be improvised. At the same time, lack of integration between different modes in the European transportation system meant that had the crisis continued any longer there would have been severe problems in moving stranded people and commodities, as well as soaring economic losses. Eruptions similar to or more serious than that of Eyjafjallaj?kull are perfectly possible in Europe in the not-too-distant future.

关键词： Atmosphere aviation meteorological

Phylogeny and evolutionary significance of vermiform animals from the Early Cambrian Chengjiang Lagersttte

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Science China Earth Sciences 2010年第12期53卷 1774-1783页

作者： david BAINES Department of Geology University of Leicester

The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail,which provide a unique window into the origin and early evolution of different vermiform *** article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far,and specifically comments on the phylogeny,modes of life,evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian *** article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology,including taphonomy and shape change caused by vermiform movement,as well as proposing that Anningvermis multispinosa and Corynetis brevis are *** vermiform animals displayed a great diversity of morphologies and ecological roles,which is significant for understanding the origin and evolution of early metazoans;the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy,geochemistry,cladistics,and genetics.

关键词： Chengjiang Biota vermiform animals priapulid lobopodian taphonomy

Economic evaluation of agricultural pollution control options for China

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Journal of Integrative Agriculture 2015年第6期14卷 1045-1056页

作者： david Abler Agricultural Environmental & Regional Economics and Demography Penn State University

Environmental sustainability has become a policy priority in China. In agriculture, China has had major success in rehabilitating desertified lands through programs to convert steeply-sloped cropland to forest and limit grazing on sensitive grasslands. However, little has been done in terms of policies for agricultural nutrient management. Runoff and leaching of nutrients in chemical fertilizers and livestock manure are widely acknowledged as significant problems in China. This paper presents an evaluation of agricultural nonpoint pollution control options for China. Options analyzed include design standards（command ＆ control）, performance standards, and design and performance incentives. Evaluation criteria include economic efficiency and effectiveness, environmental impact and risk, and social criteria such as equity and food security. The evaluation indicates that the best options for China involve subsidies to farmers for changing production practices in order to reduce nonpoint emissions, combined with appropriate farmer education and technical assistance.

关键词： agricultural fertilizers agriculture options equity livestock emissions nutrients farmer instruments

Morphology and contact mechanics influence adhesive characteristics of Dung Beetle's bristle and Gecko's setae

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Progress in Natural Science:Materials International 2007年第9期17卷 1074-1081页

作者： Yue david China Institute of Bio-Inspired Structure and Surface Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016

Geckos(Gekko gecko)use their hairy setae to adhere on various solid surfaces and dung beetles(Copris ochus Motschulsky)use their hairy bristles to anti-adhere in sticky *** study why two hairy systems express a conflict in functions by using SEM,histological approaches and functional *** models and various parameters were collected and *** on the morphological data and functional experimental results carried out by natural and denatured gecko setae and beetle bristles,we first demonstrated that the stiffness along the hair is 1000 to 30000 times that perpendicular to the *** stiffness difference is the key factor leading to the two hairy systems’ functional *** of gecko setae reduces contact stiffness,increases contact points and real contact area that results in amazing adhesive *** the other hand,stiff bristles in a beetle have higher contact stiffness,which reduces the real contact area and decreases the adhesion between two contact *** of gecko setae destroys the hierarchical structure,increases the contact stiffness and results in a decrease of adhesion ***,deformation of beetle bristles destroys the erect structure of the hair,interconnects the separated bristles and thus decreases the anti-adhesive *** observations inspire us in designing anti-adhesive and adhesive biomimetic systems

关键词： Adherence Morphology Contact stiffness Beetle bristles Gecko setae Contact mechanics

Fossil gastropods from the MGS3 stratigraphic segment in the Salawusu River Valley and their climatic and environmental implications

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Science China Earth Sciences 2008年第3期51卷 339-348页

作者： david Dian Department of Geography and Geology the University of Hong Kong

Contemporaneous with MIS3, the MGS3 segment of the Milanggouwan stratigraphic section in the Salawusu River Valley, Mu Us Desert, China contains fossil gastropods (terrestrial and freshwater snails) in strata 33LS, 35LS, 37FL and 39LS. Examination of these fossils revealed 11 species belonging to 8 families and 10 genera. They can be classified as: (1) assemblage of Gyraulus and Galba mainly consisting of Gyraulus convexiusculus, Gyraulus sibiricus, Galba pervia and Galba superegra Gredler, etc. (2) assemblage of Vallonia mainly consisting of terrestrial snails, such as Vallonia patens, Pupilla muscorum and Discus paupe, etc. Based on the dating results, and the living habits, living conditions, and geographic distribution of their extant species, we suggest that: the ages of 33LS, 35LS, 37FL, and 39LS are 26000, 29000, 33000 and 38000 a, respectively, corresponding well to the interstadial period in GRIP 4, 5, 6 and 10 in terms of chronology and climatic characters; 33LS, 35LS and 39LS represent very warm-humid periods, while 37FL represents a less warm-humid period; the four periods of climatic fluctuations recorded in MGS3 were related to the strong impact of the summer monsoon in East Asia in Mu Us Desert of China during the interstadial of MIS3 on a global climatic background.

关键词： Salawusu River Valley Milanggouwan Section MGS3 stratigraphic segment fossil gastropods climatic environment