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1.
什么是可持续性科学? 总被引:1,自引:0,他引:1
可持续发展是我们时代的主题,也是人类面临的最大挑战.自20世纪70年代,尤其是近20年来,可持续发展的概念日益频繁地出现在学术文章、政府文件以及公益宣传和商业广告之中.然而,为可持续发展提供理论基础和实践指导的科学——可持续性科学——是在21世纪初才开始形成的.该科学在短短的十几年中迅速开拓、不断发展,正在形成其科学概念框架和研究体系.中国是世界大国,是可持续性科学的哲学思想——"天人合一"——的故乡,有必要承担起时代之重任,在追求"中国梦"的同时促进全球可持续发展,并积极参与进而引领可持续性科学的研究和实践.为了帮助实现这一宏伟而远大目标,本文拟对可持续性科学的基本概念、研究论题和发展前景作一概述.可持续性科学是研究人与环境之间动态关系——特别是耦合系统的脆弱性、抗扰性、弹性和稳定性——的整合型科学.它穿越自然科学和人文与社会科学,以环境、经济和社会的相互关系为核心,将基础性研究和应用研究融为一体.可持续发展的核心内容往往因时、因地、因人而异.因此,可持续性科学必须注重多尺度研究,同时应特别关注50到100年的时间尺度和景观以及区域的空间尺度.景观和区域不但是最可操作的空间尺度,同时也是上通全球、下达局地的枢纽尺度.可持续性科学需要聚焦于生态系统服务和人类福祉的相互关系,进而探讨生物多样性和生态系统过程,以及气候变化、土地利用变化和其他社会经济驱动过程对这一关系的影响.我们认为,景观和可持续性是可持续性科学的核心研究内容,也将是可持续性科学在以后几十年的研究热点. 相似文献
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基于生态容量的广东省资源环境基尼系数计算与分析——与张音波等商榷 总被引:6,自引:1,他引:5
张音波等认为:资源环境基尼系数是用来反映在"经济贡献率"相同的情况下,资源消耗、污染物排放公平程度的一个指标,并用"绿色贡献系数"来判断资源消耗与污染物排放的不公平因子.这种基于GDP来计算的"资源环境基尼系数"会产生一种"经济越发达的地区就可以多污染"的误解,且这种"越富裕越有排污权消耗权"的理论与生态学的生态容量理论是相背离的.正确的分析方法应该是"基于'环境或生态容量'的资源环境基尼系数",从生态容量的角度,重新定义资源环境基尼系数,并确立基于生态容量的"绿色负担系数"来评价其不公平性.选取广东省2005年各城市SO2排放、工业固废产生、废水排放和能源消耗为评价指标,选取在统计资料上统计的便于分析对照的"森林面积"和"耕地面积"指标为"生态容量"的表征指标,计算其资源环境基尼系数和绿色负担系数.结果表明,2005年广东省上述4项指标的资源环境基尼系数分别为0.65、0.58、0.60、0.57,均明显高于0.4的"警戒线",说明广东省资源环境容量分配差异较大.从绿色负担系数来看,研究结果与张音波等的结果恰恰相反:在广东21个城市中,深圳、佛山、东莞、中山、广州等经济发达城市是主要的不公平因子,是需要转变经济发展模式的城市,更须注重经济与环境的协调发展. 相似文献
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在"生态系统能量流动"一节教学中,组织学生从微观到宏观分别研究各生命系统的能量流动过程,建立、分析、研究能量流动模型,总结归纳生态系统能量流动的概念及能量流动规律,应用规律解决问题,提高节约粮食的意识,教学过程中不断地发展科学思维并形成系统观、物质与能量观. 相似文献
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中国旧石器文化的“西方元素”与早期人类文化进化格局 总被引:2,自引:0,他引:2
本文回顾和分析中国旧石器研究史上有关"西方元素"即西方旧石器文化标志性技术和工具问题的争论,得出三点结论:1)"西方元素"在中国旧石器文化中是与西方同类技术和工具大体同步出现的客观现象,两者无本质差别;2)和西方一样,中国旧石器的"西方元素"也有重叠与穿时性.这使得旧大陆两侧的旧石器文化连成一体,难分东西;3)基于以上事实,本文作者倾向于认为:迄今已知的旧大陆旧石器文化是过去200多万年间早期人类在进化过程中应对全球气候波动引起的生态环境变迁而反复进行的横贯大陆的双向迁移、交流与融合的结果. 相似文献
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“973”项目“农林危险生物入侵机理与控制基础研究”简介 总被引:1,自引:0,他引:1
2002年12月,国家重点基础研究发展计划("973"项目)"农林危险生物入侵机理与控制基础研究"经科技部批准正式立项,2003年启动。文章主要介绍该项目的立项背景、主要研究内容、研究方案和技术路线、总体研究目标及研究进展。 相似文献
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《网页制作与设计》课程是一门操作性强、实用性强的课程,本文主要是站在职业教育的角度从教学设计、教师的"教"和学生的"学"三个方面入手进行研究,通过从教学案案、教学设计上改革达到提升教学效果的目的。 相似文献
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在普通高中<生物课程标准>的内容标准中,"胚胎工程"是选修3"现代生物技术专题"模块的第3个专题.该专题涉及胚胎工程的理论基础,胚胎工程的基本技术及原理,胚胎工程的应用与前景,以及胚胎于细胞的研究和应用对生命基础科学研究的重大作用等内容.笔者将从知识内容、学习目标、教学策略和教学建议等方面,谈谈对该专题的教学构思. 相似文献
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Resident Arctic charr, Salvelinus alpinus, are widespread throughout the island of Newfoundland. This study examines aspects of the biology and spatial and temporal distributions of the charr of Gander Lake, the third largest in Newfoundland (surface area = 11320ha, maximum depth = 288m, mean depth = 105.4m). The deepest part of the lake is approximately 258m below sea level. The lake is well oxygenated from the surface to the bottom during all seasons. Sampling was conducted with Lundgren multiple-mesh experimental gillnets and baited hooks. There appears to be two morphs present, based on colour (dark and pale) and certain meristic characteristics. Dark charr were caught mainly in benthic nets (at depths from 1 to 100m inclusive) with only a few pelagic captures. Pale charr were caught only in benthic nets at depths between 20 and 100m inclusive. The maximum depth sampled was 196m, but there was no catch. There was a tendency for dark charr to be found in deeper, cooler water as the upper water column and inshore areas warmed during summer. There was no apparent trend in size of charr with depth sampled. Dark and pale charr both fed on benthic macroinvertebrates; sticklebacks were consumed only by dark charr and the importance of this prey item increased with size of predator. Zooplankton and surface food were not utilised by Gander Lake charr. Results of the study are compared with findings reported for other water bodies in Newfoundland and Labrador, North America, and Europe, particularly Loch Ness which has similarities in morphometry and trophic status to Gander Lake. 相似文献
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Yung-Sheng Huang Jim-Wen Liu Kazunori Koba Steven N. Anderson 《Molecular and cellular biochemistry》1995,151(2):121-130
Metabolism of n-6 and n-3 fatty acids in the undifferentiated and differentiated human adenocarcinoma colon cell line (Caco-2) was studied. In cells incubated with either 182n-6 or 183n-3, no significant amounts of long chain n-6 and n-3 metabolites were found. Incubation with either 183n-6 or 184n-3 raised significantly the levels of 203n-6 and 204n-3, respectively. In the undifferentiated cells, significant proportions of 203n-6 and 204n-3 were further 5-desaturated to form 204n-6 and 205n-3, respectively. Incubation with either 204n-6 or 205n-3 raised the levels of their direct elongation products, 224n-6 and 225n-3, respectively. Incubation with 224n-6 or 225n-3 increased the levels of 204n-6 and 205n-6. These results suggest that 6-desaturation in the Caco-2 cells is less active in comparision with elongation, 5-desaturation and retro-conversion. These enzymes were modulated by the state of differentiation, and appeared to be non-specific to n-3 and n-6 fatty acids. When cells were incubated with 183n-6 and 184n-3 concomitantly, the levels of incorporation of total n-6 fatty acids into cellular lipids were greater than those of the n-3 fatty acids, whereas the ratios of 20+22 carbon metabolites to 18-carbon precursor favored n-3 over n-6 fatty acids. These results suggest that n-3 and n-6 fatty acids were not metabolized identically in Caco-2 cells. 相似文献
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Marissa McClure Patricia Tarr Christine Marmé Thompson Angela Eckhoff 《Arts Education Policy Review》2017,118(3):154-163
ABSTRACTThis article reflects the collective voices of four early childhood visual arts educators, each of whom is a member of the Early Childhood Art Educators (ECAE) Issues Group of the National Arts Educators Association. The authors frame the article around the ECAE position statement, Art: Essential for Early Learning (2016), which focuses on the central role of art interactions among young children, educators, environments, and materials. The authors describe eight principles that underlie the statement from philosophical viewpoints, and provide practical examples of the principles in action. Amid a varied policy landscape for visual art in early childhood, the authors assert that children need organized, materials-rich environments that invite discovery, interaction, sensory and kinesthetic exploration, wonder, inquiry, and imagination in relationship with responsive educators who value young children's diverse abilities, interests, questions, ideas, and cultural experiences. The authors explore issues and possibilities resulting when educators work to bring visual arts fully and dynamically into the lives of young children in diverse education and care spaces. In closing, the authors explore the realities of visual arts policies in the early childhood education and art education fields while emphasizing the critical need for supportive pedagogical practices in all early childhood classrooms. 相似文献
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Natacha Brion Willy Baeyens Sandra De Galan Marc Elskens Remy W.P.M. Laane 《Biogeochemistry》2004,68(3):277-296
Annual nitrogen and phosphorus budgets for the whole North Sea taking into account the most recent data available were established. The area considered has a total surface of approximately 700,000km2 and corresponds to the definition by OSPARCOM (Oslo and Paris Commission) with the exclusion of the Skagerrak and Kattegat areas. Input and output fluxes were determined at the marine, atmospheric, sediment and continental boundaries, and riverine inputs based on river flows and nutrient concentrations at the river–estuary interface were corrected for possible estuarine retention. The results showed that the North Sea is an extremely complex system subjected to large inter-annual variability of marine water circulation and freshwater land run-off. Consequently, resulting total N (TN) and P (TP) fluxes are extremely variable from 1 year to another and this has an important influence on the budget of these elements. Total inputs to the North Sea are 8870±4860kTNyear–1 and 494±279kTPyear–1. Denitrification is responsible for the loss of 23±7% of the TN inputs while sediment burial is responsible for the retention of only of 2±2% of the TP input. For TN, due to the large variability on marine and estuarine fluxes, and to the uncertainty related to the denitrification rate, it was concluded that the North Sea could either be a source (1930kTNyear–1) or a sink (1700kTNyear–1) for the waters of the North Atlantic Ocean. For TP it was concluded that the North Sea is mostly a source (–4 to 52kTPyear–1) for the waters of the North Atlantic Ocean. 相似文献
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Summary The eukaryotic 5.8S and the chloroplast 4.5S ribosomal RNAs were proposed to have arisen from the 5 and 3 ends respectively of prokaryotic 23S ribosomal RNA by the introduction of new processing sites during evolution. This hypothesis was supported by comparison of previously published primary sequences; in addition we can draw models of secondary structure in accord with this notion. Finally, we further noted that the sequence of processing cuts in the maturation pathway of ribosomal RNA reflects the probable order in which they arose during evolution. 相似文献
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Isoelectrofocusing, product analysis, thermal denaturation studies and affinity chromatography on cycloheptaamylose-Sephadex were used to identify the amylolytic enzymes in internodes of deepwater rice (Oryza sativa L.). Amylolytic activity in internodes of deepwater rice consists of -amylase (sometimes separated into two isoforms) and of -amylase. During submergence of whole plants, -amylase activity increases in young, growing internodes, but -amylase activity declines. Although non-growing, mature internodes contain higher levels of -amylase than do the elongating younger internodes, the effect of submergence on amylase activities in both tissues follows the same trend. Submergence, gibberellic acid (GA3) and ethylene all promote -amylase activity in growing and non-growing internodes of excised deepwater-rice stem sections. Inhibitor studies showed that submergence and ethylene promote -amylase activity in the absence of endogenous gibberellin (GA), and GA3 enhances -amylase activity when ethylene action is inhibited. Therefore, ethylene and GA appear to increase -amylase activity independently of each other. Enhanced -amylase activities are probably responsible for the mobilization of carbohydrates which are needed to support internode elongation during submergence of deepwater rice.Abbreviations CHA
cycloheptaamylose
- GA3
gibberellic acid
- NBD
2,5-norbornadiene
- TCY
tetcyclacis 相似文献
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Zooplankton spatial heterogeneity has profound effects on understanding and modelling of zooplankton population dynamics and interactions with other planktonic compartments, and consequently, on the structure and function of planktonic ecosystems. On the one hand, zooplankton heterogeneity at spatial and temporal scales of ecological interest is an important focus of aquatic ecology research because of its implications in models of productivity, herbivory, nutrient cycling and trophic interactions in planktonic ecosystems. On the other hand, estimating zooplankton spatial variation at the scale of an ecosystem, is a powerful tool to achieve accurate sampling design. This review concentrates on the spatial heterogeneity of marine and freshwater zooplankton with respect to scale. First to be examined are the concept of spatial heterogeneity, the sampling and statistical methods used to estimate zooplankton heterogeneity, and the scales at which marine and freshwater zooplankton heterogeneity occurs. Then, the most important abiotic and biotic processes driving zooplankton heterogeneity over a range of spatial scales are presented and illustrated by studies conducted over large and fine scales in both oceans and lakes. Coupling between abiotic and biotic processes is finally discussed in the context of the multiple driving forces hypothesis.Studies of zooplankton spatial heterogeneity refer both to the quantification of the degree of heterogeneity (measured heterogeneity) and to the estimation of the heterogeneity resulting from the interactions between the organisms and their environment (functional heterogeneity) (Kolasa & Rollo, 1991). To resolve the problem of measuring zooplankton patchiness on a wide range of spatial scales, advanced technologies (acoustic devices, the Optical Plankton Counter (OPC), and video systems) have been developed and tested in marine and freshwater ecosystems. A comparison of their potential applications and limitations is presented. Furthermore, many statistical tools have been developed to estimate the degree of measured heterogeneity; the three types most commonly used are indices of spatial aggregation, variance: mean ratio, and spatial analysis methods. The variance partitioning method proposed by Borcard et al. (1992) is presented as a promising tool to assess zooplankton functional heterogeneity.Nested patchiness is a common feature of zooplankton communities and spatial heterogeneity occurs on a hierarchical continuum of scales in both marine and freshwater environments. Zooplankton patchiness is the product of many physical processes interacting with many biological processes. In marine systems, patterns of zooplankton patchiness at mega- to macro-scales are mostly linked to large advective vectorial processes whereas at coarse-, fine- and micro-scales, physical turbulence and migratory, reproductive and swarm behaviors act together to structure zooplankton distribution patterns. In freshwater environments, physical advective forces related to currents of various energy levels, and vertical stratification of lake interact with biological processes, especially with vertical migration, to structure zooplankton community over large to fine- and micro-scales. Henceforth, the zooplankton community must be perceived as a spatially well-structured and dynamic system that requires a combination of both abiotic and biotic explanatory factors for a better comprehension and more realistic and reliable predictions of its ecology. 相似文献
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Zusammenfassung Untersuchungen des Bindegewebes der stylommatophoren Pulmonaten Helix pomatia and Cepaea nemoralis zeigen, daß die Blasenzellen des Bindegewebes befähigt sind, Substanzen aus der Hämolymphe aufzunehmen. Licht- und elektronenmikroskopische Untersuchungen ausgewählter Bindegewebsbereiche, die in bestimmten Zeitintervallen nach der Injektion von Trypanblau oder Ferritin in die Körperhöhle präpariert wurden (Stufenuntersuchungen), ergaben, daß — mit Ausnahme einiger Blutzellen — ausschließlich die Blasenzellen die injizierten Substanzen aufgenommen hatten. Weder andere Bindegewebszellen noch die Zellen von Organen (u.a. Gonaden, Schlundringganglien), die von Bindegewebe umgeben werden, enthielten diese Substanzen oder hatten sie akkumuliert. Die elektronenmikroskopischen Aufnahmen zeigen, daß die Aufnahme von Ferritin in die Blasenzellen wahrscheinlich durch Pinocytose erfolgt.
Uptake of trypan blue and ferritin into the globular cells of the connective tissue of Helix pomatia and Cepaea nemoralis (Stylommatophora, Pulmonata)
Summary Investigations of the connective tissue of the stylommatophoran pulmonates Helix pomatia and Cepaea nemoralis have demonstrated, that so-called globular cells have the capability for the uptake of substances out of the hemolymph. Light- and electron-microscopic investigations of pieces of connective tissues fixed at different intervals after the injection of Trypane Blue or Ferritin into the cavity of the body give striking evidence for the uptake of these substances exclusively into the globular cells (with the exception of some blood cells). Neither other connective tissue cells nor cells of the organs (e.g. gonads, central nervous ganglions) surrounded by connective tissue incorporate or accumulate the injected substances. The uptake of Ferritin into the cytoplasm of the globular cells, normally filled with a high amount of glycogen, takes place by pinocytosis.相似文献