On the evolutionary ecology of host-parasite interactions: addressing the question with regard to bumblebees and their parasites

Over the last decade, there has been a major shift in the study of adaptive patterns and processes towards including the role of host-parasite interactions, informed by concepts from evolutionary ecology. As a consequence, a number of major questions have emerged. For example, how genetics affects host-parasite interactions, whether parasitism selects for offspring diversification, whether parasite virulence is an adaptive trait, and what constrains the use of the host's immune defences. Using bumblebees, Bombus spp, and their parasites as a model system, answers to some of these questions have been found, while at the same time the complexity of the interaction has led expectations away from simple theoretical models. In addition, the results have also led to the unexpected discovery of novel phenomena concerning, for instance, female mating strategies.     

Chemical compounds of the foraging recruitment pheromone in bumblebees

When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees.     

Chemical interactions between amino acid and RNA: multiplicity of the levels of specificity explains origin of the genetic code

The emergence of the genetic code remains an enigma. Proposed mechanisms are based on random, historical, thermodynamic and natural selection. However, they introduce chance as a key factor for overcoming the difficulties encountered by the model. We propose here a model in which three successive levels of chemical specificity generated the nucleotide assignments of amino acids in the genetic code. The first level results from hydrophobic and stereospecific interactions between amino acids and short oligonucleotides (termed oligons). The second and third levels of specificity are determined by conditions of energy transfer from loaded oligons (amino acid-oligomer covalently linked) to formation of phosphodiester bond (second level of specificity) and peptidic bond (third level of specificity), while these reactions are catalyzed by RNA templates. This model is sustained by the relationships observed between dipole moments of the nucleotides (forming the anticodon) and reactivity of the amino acyl linkage of the loaded oligon. Moreover, analysis of modern tRNAs reveals that they were probably generated by loose duplication of the nucleotide sequence forming the oligons, after emergence of the 'genetic code.' Indeed, the similarity of nucleotide composition with that of the anticodon decreases with the tRNA domain's distance from the anticodon, but the acceptor stem is relatively more similar to the anticodon than other stems closer to it. This would be because energy transfer constraints that existed between anticodon and amino acid in prebiotic loaded oligonucleotides still affect the structures of modern tRNA acceptor stems. In the model presented, the genetic code is inherent to the most archaic 'molecular physiology' in protolife, even before emergence of a functional 'protein world.' Simple physical processes, in which a level of specificity is integrated in an emerging meta-structure expressing new properties, generate a parsimonious and realistic explanation of emergence of the genetic code.     

Chemical speciation and anthropogenic sources of ambient volatile organic compounds(VOCs)during summer in Beijing,2004

Volatile organic compounds (VOCs) were measured at six sites in Beijing in August, 2004. Up to 148 VOC species, including C₃ to C₁₂ alkanes, C₃ to C₁₁ alkenes, C₆ to C₁₂ aromatics, and halogenated hydrocarbons, were quantified. Although the concentrations differed at the sites, the chemical compositions were similar, except for the Tongzhou site where aromatics were significantly high in the air. Based on the source profiles measured from previous studies, the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance (CMB) model. The results show that urban VOCs are predominant from mobile source emissions, which contribute more than 50% of the VOCs (in mass concentrations) to ambient air at most sites. Other important sources are gasoline evaporation, painting, and solvents. The exception is at the Tongzhou site where vehicle exhaust, painting, and solvents have about equal contribution, around 35% of the ambient VOC concentration. As the receptor model is not valid for deriving the sources of reactive species, such as isoprene and 1,3-butadiene, other methodologies need to be further explored.     

Industrial ecology: a new field or only a metaphor?

In the 10 years since industrial ecology first became a topic of academic interest, it has grown as a field of inquiry and has produced a community of practice in several sectors including academia, business, and government. Even as the shape of industrial ecology becomes clearer, questions remain as to its lasting power beyond the metaphor that gave it its distinctiveness. This paper examines the development of industrial ecology and assesses its progress towards becoming a field of academic inquiry. And, in a related analysis, I look at the progress industrial ecology has made in establishing itself as an institutional (cultural) basis for action in the above sectors. Ideas like industrial ecology must become institutionalized if they are to have much effect on the reality of everyday activities.     

绿色南雄和谐发展--采访南雄市副市长刘发雄

近日,记者一行来到南雄,就该市经济发展与环境保护的相关问题,采访了南雄市副市长刘发雄.     

石油输送多功能无线数据监控系统开发与应用

采用嵌入式操作系统,应用温压一体式传感器,结合无线网络,能及时发现油田油井生产管线上打孔盗油、凿眼破坏和管线穿孔等情况,实现线路巡查不需专人值守。根据温度、压力等数据的变化分析判断油井的生产情况。     

Chemical evolution: The first stages

The available data on the syntheses of critically important precursor molecules for chemical evolution are reviewed and problems of rates of production versus rates of destruction in the primitive ocean are discussed. It is concluded that many global chemical syntheses would have been improbable in the Earth's oceans and that more attention should be paid to specific environments which would have favored such syntheses. The recent discovery of an accelerating effect of formaldehyde on the oligomerization of HCN as well as the eutectic-concentration mechanism are discussed in relation to a new scenario for chemical evolution on the primitive Earth.     

化学基本观念:内涵分析与教学建构

通过对国内外有关学科观念研究的梳理,我们对学科思想与学科观念、学科基本观念与大概念(big ideas)等术语进行了辨析,深入论述了化学基本观念的含义和内容体系,并进一步阐释化学基本观念是否可教以及实施观念建构的化学教学的意义。     

Teaching industrial ecology and environmental management in Second Life

Second Life is a virtual, open-access, and user-generated environment that has served as a platform for hosting everything from rock concerts to scientific conferences. Many institutions have also used Second Life as an educational tool, for example by, showcasing scientific exhibits or embedding video and images for learning purposes. Here we discuss the creation and use of an interactive, virtual industrial facility - the Elihu Paper Company - as a way to complement a traditional facility tours in a course in industrial environmental management. Virtual facilities offer a number of educational advantages over real-life ones: they are always open and available for tours, they can be accessed instantaneously from anywhere where there is an adequate internet connection, and most importantly, tours and embedded information can be tailored to specific educational objectives. Our experience in using Elihu Paper as a formal facility visit for the past several years shows that students had significantly more time than usual to ask questions, could and did explore the facility independently, and were still able to produce facility reports that fulfilled the educational objectives of the visits, including mapping material flows and explaining pollution prevention and sustainability opportunities.     

建生态示范村打造和谐人居

“十五”期间，创建生态示范村作为云浮市把执政为民、统筹城乡协调发展和贯彻落实中央、省委解决“三农”问题重大部署、建设社会主义新农村的重要举措，其成效在广东省内一枝独秀，有力地推进了云浮市农村城镇化，打造了百姓的和谐人居。     

化学农药对环境的危害原因及其防治对策

农药广泛应用于世界各国,对农业生产的发展起着重要的作用.但是随着农药的大量使用,农药对土壤、水和大气环境也造成了污染,对鸟类、昆虫及农产品品质产生了影响.中国农药污染产生的主要原因有农药产品问题、用药不规范不科学、农药的有效利用率低等.中国应从完善法规管理、淘汰高毒农药、加强技术培训、提高测报水平、开展综合防治等方面采取措施,解决农药污染问题.     

微生物絮凝剂诱变菌最佳培养条件及化学成分

从活性污泥中分离、筛选出絮凝率在80%以上的菌一株。通过培养液中絮凝活性的分布测定,发现絮凝剂属于细胞代谢产物,用化学分析的部分分析方法对絮凝剂粗提物进行检测,发现其成分主要为糖。通过生长曲线的测定,选定菌的诱变在培养72h以后进行。经过三代诱变,得到了稳定性好且絮凝率高的诱变菌。通过絮凝剂制备工艺及工艺参数的研究,确定了其最佳培养条件。     

Caudal fin allometry in the white shark Carcharodon carcharias: implications for locomotory performance and ecology

Allometric scaling analysis was employed to investigate the consequences of size evolution on hydrodynamic performance and ecology in the white shark Carcharodon carcharias. Discriminant analysis using the power equation y=ax^b was negative for caudal fin span (S) versus fork length (FL) in C. carcharias. In contrast in two delphinid species, Delphinus capensis and Tursiops aduncus, the span of the flukes versus fork length rises in positive allometric fashion, and strong positive allometry of S versus A (area) was also recorded. The latter reflects a high lift/drag ratio. S versus A in C. carcharias displays negative allometry and consequently a lower lift/drag ratio. A lower aspect ratio (AR) caudal fin in C. carcharias compared to that of the delphinids (mean 3.33 and 4.1, respectively) and other thunniform swimmers provides the potential for better maneuverability and acceleration. The liver in sharks is frequently associated with a buoyancy function and was found to be positively allometric in C. carcharias. The overall findings suggest that the negatively allometric caudal fin morphometrics in C. carcharias are unlikely to have deleterious evolutionary fitness consequences for predation. On the contrary, when considered in the context of positive liver allometry in C. carcharias it is hereby suggested that buoyancy may play a dominant role in larger white sharks in permitting slow swimming while minimizing energy demands needed to prevent sinking. In contrast hydrodynamic lift is considered more important in smaller white sharks. Larger caudal fin spans and higher lift/drag ratio in smaller C. carcharias indicate greater potential for prolonged, intermediate swimming speeds and for feeding predominantly on fast-moving fish, in contrast to slow-swimming search patterns of larger individuals for predominantly large mammalian prey. Such data may provide some answers to the lifestyle and widespread habitat capabilities of this still largely mysterious animal.An erratum to this article can be found at     

Applied research of landscape ecology in desertification monitoring and assessment

A preliminary research on landscape ecology in desertification monitoring and assessment was reported. Also, this paper laid stress on the study of landscape diversity, dominance, evenness and Markov Matrix model and their respective landscape ecological meanings in the desertification monitoring and assessment. Concurrently, it took Shazhuyu Experimental Area, Qinghai Province as a specific case study.