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1.
The aim of the paper is to review critically the notion of autopoiesis as presented by Maturana and Varela. In particular, recognizing that there are difficulties in obtaining a complete and clear picture from the primary literature, an effort is made to present a coherent view--also based on many years of personal contact with Francisco Varela. The paper begins with a few historical notes to highlight the cultural background from which the notion of autopoiesis arose. The basic principles of autopoiesis as a theory of cellular life are then described, emphasizing also what autopoiesis is not: not an abstract theory, not a concept of artificial life, not a theory about the origin of life--but rather a pragmatic blueprint of life based on cellular life. It shown how this view leads to a conceptually clear definition of minimal life and to a logical link with related notions, such as self-organization, emergence, biological autonomy, auto-referentiality, and interactions with the environment. The perturbations brought about by the environment are seen as changes selected and triggered by the inner organization of the living. These selective coupling interactions impart meaning to the minimal life and are thus defined by Maturana and Varela with the arguable term of "cognition". This particular view on the mutual interactions between living organism and environment leads these authors to the notion of "enaction", and to the surprising view that autopoiesis and cognition are two complementary, and in a way equivalent, aspects of life. It is then shown how cognition, so defined, permits us to build a bridge between biology and cognitive science. Autopoiesis also allows one to conceive chemical models of minimal cellular life that can be implemented experimentally. The corresponding work on "chemical autopoiesis" is then reviewed. The surprising impact of autopoiesis in the social sciences ("social autopoiesis") is also briefly discussed. This review also comments on why the theory of autopoiesis had, and still has, a difficult time being accepted into the mainstream of life-science research. Finally, it is pointed out that the new interest in system biology and complexity theories may lead to a reappraisal of autopoiesis and related notions, as outlined also by other authors, such as Tibor Ganti and Stuart Kauffmann.  相似文献   

2.
 A host invasion strategy hitherto unknown from other insect parasitoids was observed in the dipteran Acrocera orbicula (Fabricius) (Diptera: Acroceridae) parasitizing the wolf spider, Pardosa prativaga (L. Koch) (Araneida: Lycosidae). In laboratory experiments the free-living first instar acrocerid larvae attached themselves firmly to the spiders' integument by the mouthparts, cutting a tiny hole through the integument. No first instar larvae invaded the host. A week later the parasitoids molted, and a small, flexible, and glabrous second instar larva left each of the attached first instar exuviae and invaded the host through the attachment hole of the first instar larva. The novel host invasion pattern observed may reduce physical damage to the host in the initial phase of endoparasitism, enhancing parasitoid survival. Received: 14 April 1999 / Accepted in revised form: 2 July 1999  相似文献   

3.
公众环境意识与可持续发展关系初探   总被引:1,自引:0,他引:1  
目前,国内存在的各种环境问题,归根到底是由于发展战略的不同所致,人们开始重新去认识和评价传统发展战略的局限性,标志着人类文明即将步入一个被称之"环境文明"新的历史时代.历史文化传统和经济发展水平决定公众环境意识,公众的环境意识直接影响可持续发展战略的实施,如何增强,提出决策和建议,通过大力开展环境宣传教育,提高公众环境意识,可持续发展,实现可持续发展的战略.  相似文献   

4.
A hopper-predator community in an experimental rice field was observed weekly with regard to information content (H′), formation of a geometric series or the grade of orderly distribution of component taxa (R2), and clumping index (I). These community attributes changed with time in close association with one another, and attained the highest values around the heading time of the rice. Significant correlations were found between the density of prey and that of predators when a certain time-lag was assumed for the increase of predators.  相似文献   

5.
"十一五"是我国经济社会发展的重要战略机遇期,也是环境保护工作极具挑战的时期.我们将以党的十六届五中全会精神为指针,以建设"绿色重庆"为目标,以"预防为主、综合治理,不欠新账、多还旧账,创新机制、强化监管,突出重点、分类指导,典型示范、带动全面"为基本原则,发展循环经济,解决突出问题,改善环境质量,建立工作机制,努力构建环境友好型社会.  相似文献   

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创建安静居住小区,是以营造安静和谐的宜居生活环境为目标,通过强化噪声监管、开展宣传教育等方式,改善城区声环境质量,提高居民环保意识,提高城市文明水平的一种有效方式.2009年以来,厦门市思明全区开展创建“安静居住小区”工作.目前,25个创建小区中共有24个通过验收达标.“安静居住小区”创建以来,小区居民对居住环境质量的满意率达到97%,小区噪声污染得到有效治理,居民的环保意识得到极大提高.  相似文献   

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9.
During the last three of 20 years kept as a pet, a red knot (Calidris canutus) went through two complete 'circannual' cycles of body mass and plumage. With a record cycle length of 18 months, this individual shorebird provides evidence for an exceptionally strong circannual clock system. The absence of synchronisation to outdoor but visible periodic cues suggests that the constant, socially-induced, day-night environment was of overriding importance. So far, only for songbirds is there firm experimental evidence that annual cycles are orchestrated by an endogenous circannual clock system. In constant environments the circannual cycles of these passerines tend to have periods that are shorter, rather than longer, than a year.  相似文献   

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By increasing particle concentration and G value (root-mean-square velocity gradient) to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations (500, 100 and 50 mg/L, respectively) coagulated by polyaluminum chloride(PAC1) at the up-flow rates of 1 and 2 mm/s, respectively.  相似文献   

13.
今天,全世界可能有上千个会议在召开,但我想没有任何一次会议会比我们这个会议更重要,所以我非常荣幸能够来到这里,与各位来自中国和其它国家的著名环境专家坐在一起。同时,我也非常高兴能够见到曲格平先生,他在环境领域一直扮演着领袖的角色,而且我很高兴能够在潘岳局长演讲之后进行我的发言。  相似文献   

14.
There is increasing evidence that throughout the world, firms, governmental agencies and NGOs are seeking to stimulate industrial symbiosis. This concept and its application have also been the topic of extensive research. Up till now, this work lacks a more comprehensive theoretical framework, and this paper fills this gap. We provide a theoretical basis for understanding the dynamics through which regional industrial systems change their connectiveness in an attempt to reduce their ecological impact. We position our framework within the field of industrial symbiosis based on a comprehensive literature search in the ISI Web of Science database for publications that listed ‘industrial symbiosis’, ‘eco-industrial park’, or a combination of ‘industrial-ecology’ and ‘regional’ as a topic.The framework conceptualizes industrial symbiosis as a process at two levels: (1) the level of the regional industrial system (RIS), and (2) the societal level where the concept and routines of industrial symbiosis diffuse. We link the dynamics at these levels to changes in ecological impact and increase in institutional capacity. We conclude with a research agenda based on the variables and their basic relationships specified in our framework. The main line of research we propose is to systematically investigate how institutional capacity evolves over time in regional industrial systems and how it affects the ecological impact of such systems. We also propose to investigate how insights from existing literature about stimulating and impeding factors to industrial symbiosis can be understood in terms of mechanisms of transmission and how these mechanisms interact to create nationally distinct patterns of diffusion of industrial symbiosis.  相似文献   

15.
Occipital encephalocele belongs to the family of neural tube defects, which occur in one among 2000 to 5000 live births. Syndromic encephaloceles include Meckel–Gruber syndrome and various chromosomal abnormalities. We report on a fetal case (13 WG) with bilateral cleft lip and palate, choanal atresia, occipital encephalocele, bilateral club feet, bilateral multicystic kidneys, enlarged bladder and urethral atresia. The fetal chromosome analysis showed a maternally inherited unbalanced translocation between the short arm of chromosome 1 and the long arm of chromosome 14, resulting in 1p35-pter deletion and 14q32-qter duplication (46,XY,der(1),t(1;14)(p35;q32)). Since the chromosomal breakpoints have not previously been implicated in syndromic encephalocele, this observation is of interest for the identification of other genes responsible for occipital encephalocele. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
Male-biased predation of a cave fish by a giant water bug   总被引:1,自引:0,他引:1  
Male-biased predation has been described from several epigean species, and in many cases, intrinsic differences between the sexes (such as male ornaments) have been suggested as an explanation. Here we report on male-biased predation of a cave fish (Poecilia mexicana) by an aquatic insect (Belostoma sp.) in a Mexican sulfur cave. P. mexicana use aquatic surface respiration (ASR) to survive in their sulfidic, hypoxic habitat. We found that males typically exhibit more ASR activity than females, which leads to increased exposure to the sit-and-wait predator that catches fish near the water surface. Our finding is novel, because male vulnerability to predation is not directly related to male traits involved in courtship, but rather due to other sexual differences in behavior and ultimately, oxygen demands.  相似文献   

17.
混凝剂FAS的制备及性能研究   总被引:5,自引:0,他引:5  
吴奇藩  孔庆安  王超 《环境科学》1995,16(3):41-43,51
报道利用铜矿渣制取固体混凝剂FAS。实验表明,该混凝剂具有优良的除蚀、除色、除COD、除硫性能,尤其对采用常规混凝剂难以除去的亲水性染料,FAS有独特的去除效率。对各种模拟废水和实际废水,FAS的脱色率为95%,对COD的去除率则在90%以上。本文还对FAS的混凝脱色机理进行了初步的探讨。  相似文献   

18.
A micro-scale machine tool (mMT) topology is developed for turning hardened steel bearing components. The topology utilizes the principle of leverage to increase accuracy and stiffness and incorporates decoupling to reduce unwanted motion of the tool. Performance specifications required that the static stiffness is at least 10 N/μm and dynamic stiffness is at least 30 N/μm in all directions. The kinematics for the topology are developed to enable control over the position and orientation of the tool tip. The effect of the topology on rake angle is determined and the topology is adjusted so as to minimize the rake angle variation during the cut. Cutting tests are performed to determine cutting parameters for achieving a low surface roughness and to estimate the accuracy of the machine. Tests show that the hard-turning mMT can achieve surface roughness below 25 nm Ra, diametrical accuracy of 1 μm and peak-to-valley roundness deviation (RONt) below 0.35 μm.  相似文献   

19.
Many social insect species produce signals that either recruit foragers to a specific food source or simply activate more nestmates to become foragers. Both are means of enhancing resource exploitation by increasing the number of individuals devoted to gathering profitable resources. Gastral drumming (GD) has been documented in several species of yellowjackets and hornets (Vespidae: Vespinae). It has been hypothesized that it is a hunger signal, but there is little empirical evidence to support this claim. An alternative hypothesis is that GD recruits workers to forage for food. Here, we report the results of a test between the hunger-signal and food-recruitment hypotheses in the German yellowjacket wasp, Vespula germanica. We show that the rate of performance of GD decreased when colonies were deprived of food and increased when supplemental food was provided. Playback of GD caused increased rates of (1) movement in the nest, (2) trophallaxis, and (3) worker departures from the nest. Together, these results support the conclusion that GD is not a hunger signal as previously asserted but instead is a nest-based food-recruitment signal, the first to be reported for a social wasp.  相似文献   

20.
The development and implementation of new procedures and operational changes in the production processes constitutes a powerful tool for the practical application of Cleaner Production in industries. In this work an operational change (new procedure) was developed for the elaboration of a type of beer which uses sugar as malt adjunct. The change consists in processing separately the three main components of the beer wort: malt extract, sugar and water, and use them properly in a different sequence than that used up to date in the traditional process. The new procedure was successfully assayed on industrial scale in Tínima brewery, located in Camagüey, Cuba, obtaining a good quality beer, technological and economical advantages with benefits for the environment, registering significant savings in energy (49%), sugar (4%), water (7%) and caustic soda (3%) consumption; and diminishing the surplus hot water (74%), waste generation (11%) and greenhouse gases emission (21%). Beer production capacity is increased also almost three times. With the application of the new technology to the Cuban beer type of 8 °P, it was achieved a total saving of US$ 481.83/1000 hL of beer produced.  相似文献   

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