海洋纤毛虫实验生态学研究Ⅲ:纤毛虫摄食胁迫对弧菌(Vibrio sp.)种群增长的影响

为揭示纤毛虫对弧菌 (Vibriosp.)种群增长的影响 ,利用实验生态学方法对弧菌在海水养殖水体中两种常见的纤毛虫原生动物 ,扇形游仆虫 (EuplotesvannusM櫣ｌｌｅｒ)和海洋尾丝虫 (UronemamarinumDujardin) ,摄食胁迫下的种群增长过程进行了探讨 .数据分析显示 ,弧菌的种群密度在纤毛虫的指数增长期高于对照组 ,但在纤毛虫种群生长平衡期则显著低于对照组 (P <0 .0 5 ) ,在纤毛虫种群生长衰退期则呈回升的趋势 .结果同时还表明 ,海洋纤毛虫的摄食胁迫对弧菌的繁殖具有明显的激活效应 ,但对其种群生长起着显著的抑制作用 .此外 ,本工作也进一步证实了食菌性纤毛虫对改良水质和维持一个健康的养殖环境所具有的积极作用 .图 6参 15     

构建限制性条件下微生物群体生长模型时的问题

Logistic生长模型在表征营养限制性生长条件下微生物群体生长时,遇到了种种困难．该模型未能明确给出微生物群体生长的“延迟期”和“代时”两个重要生长动力学参数,也忽视了方程中参数“r”应为平均生长速率,且不具有内禀生长率性质等诸多生物学特点．采用E．coli ATCC31343,37℃液体摇瓶培养下获得的实验数据,证实了Logistic模型存在的上述局限性．通过对E．coli以葡萄糖和山梨醇共作碳源时,表现出的“二峰生长”曲线与用Logistic方程拟合结果的比较,表明适合度分析（goodness—fit test）不能作为模型是否适合的唯一判据．并对构建微生物群体生长模型的策略进行了讨论．图5参31     

Maternal effects on post-weaning physical and social development in juvenile mountain goats (Oreamnos americanus)

Little is known about maternal effects on post-weaning development, yet they may be important because maternal care could have long-term consequences only evident when offspring approach adulthood. We have assessed the effects of maternal age, current reproduction (presence of a kid of the year) and social rank on the body mass, horn length and social rank of 1- and 2-year-old mountain goats (Oreamnos americanus). Maternal reproductive status and social rank did not affect the mass or horn length of either yearlings or 2-year-olds. Maternal age was positively correlated with yearling body mass for males but not females. We could not detect any maternal age effects on body mass of 2-year-olds. Maternal age and spring forage quality were positively correlated with horn length of yearlings of both sexes, but not of 2-year-olds. Juvenile females showed compensatory growth in mass between 1 and 2 years of age, but males did not. Neither sex showed compensatory growth in horn length. None of the maternal characteristics we examined directly affected the social rank of juveniles, which increased with body mass. Social rank in female mountain goats seems to be established early in life and maintained to adulthood. By affecting yearling development, maternal age could affect the reproductive success of males.     

Scarcity, growth and R&D

The limits to economic growth due to resource scarcity can be alleviated only by the development of backstop substitutes. This paper combines resource-based economic growth with R&D to reduce the cost of backstop technologies. Characterizing the entire dynamics of optimal growth and R&D processes, we find that an economy's growth prospects depend on its type, as determined by its production technology and learning ability, and by its knowledge–capital endowment. A wide variety of growth patterns emerges, ranging from cases in which an economy that without R&D eventually stagnates (converges to a steady state) is diverted by R&D onto a path of sustained growth, to cases in which R&D is not warranted. Resource scarcity is shown to encourage R&D due to the increased reliance on the backstop technology.     

金龟子绿僵菌固体培养条件的筛选

测定了不同温度和pH及碳氮源、微量元素对金龟子绿僵菌菌丝生长及产孢的影响．结果表明：pH7、温度25℃最适合绿僵菌生长，固体培养中蔗糖为碳源、酵母为氮源、加入微量元素Mn，金龟子绿僵菌生长最好、产孢量最高．用正交方法探索了金龟子绿僵菌的最适固体培养条件．表6参10     

芦苇化感组分对斜生栅藻Scenedesmus obliquus生长特性的影响

水华或赤潮现象是备受关注的环境问题之一。利用植物化感作用抑制藻类生长作为一种新型的生物抑藻技术在近年来开始受到研究者的重视,并取得了一定的研究成果。文章研究了从芦苇PhragmitiscommunisTrin中分离得到的化感组分对斜生栅藻Scenedesmusobliquus生长特性的影响。在藻类的对数生长期向培养液中投加不同浓度的化感组分,分别测定并观察了培养期间受试藻种藻密度、藻细胞结构和群体形态的变化。结果表明,该化感组分在培养初期对斜生栅藻藻密度的增长具有明显的抑制作用,半效应质量浓度(EC50,4d)值为0.45mg·L-1,但在培养6d后,出现促进作用,且随投加浓度的增加而增强。斜生栅藻生长受到抑制期间,藻细胞形态变大,投加0.5mg·L-1化感组分时,藻细胞平均宽度是对照组的2倍。TEM观察观察结果表明藻细胞亚显微结构受到破坏。另外,EMA提高了斜生栅藻的沉降性和吸附性。     

DEFORMITIES IN CULTURED CHIRONOMUS TENTANS LARVAE AND THE INFLUENCE OF SUBSTRATE ON GROWTH, SURVIVAL AND MENTUM WEAR

Effects of four substrates (shredded papertowelling, coarse sand, fine sand, and silty clay)on growth, survival and mentum wear of Chironomustentans larvae were investigated in thelaboratory. Three categories of mentum wear were defined:minimal, moderate and substantial. Thenumber of larvae with worn mentum teeth did not differ in anyof the four substrates. However, thenumber of larvae with minimal wear of their teeth wassignificantly different among the substrates andwas in the order coarse sand > shredded paper towelling >clay/silt > fine sand. Mentumdeformities were observed in the cultured larvae, presumablybecause of inbreeding and not the effectof treatment. Differences in biomass and survival of larvaeamong the substrates were not significant(p<0.05), however, there was a trend for lower survival inthe sand substrates. These findingssuggest that shredded paper towelling is the most suitablereference substrate. The occurrence ofnatural abnormalities must be considered when using chironomidmouthpart deformities as an index of environmental degradation.     

One independent variable rate equation describing utilization of biodegradable organic matter in activated sludge processes

This investigation aims to represent aerobic utilization of biodegradable organic matter present in wastewater by a rate equation. This rate equation can then be used to develop a substrate utilization (removal) kinetic model for unsteady state activated sludge process. To achieve this objective, theoretical utilization of biodegradable organic matter in batch process and growth pattern theory were studied. Also, experimental data representing removal of organic matter in different types of wastewaters were collected and analyzed for batch and continuous activated sludge assays. A rate equation was proposed to describe the utilization of biodegradable organic matter based on theoretical analysis of batch process. This rate equation was then verified through differential and integral analysis of the experimental data. Furthermore, a substrate kinetic model for batch and continuous processes was developed. The developed rate equation will facilitate the analysis and design of sequencing batch reactor (SBR) technology for biological treatment of wastewater.     

Fuzzy dynamic risk-based maintenance investment optimization for offshore process facilities

A methodology for maintenance planning is developed which helps in improving the reliability of the components and safety performance in process facilities. This methodology helps design an optimum safety maintenance investment plan by integrating the optimization techniques and a fuzzy dynamic risk-based method. Intuitionistic Fuzzy Analytic Hierarchy Process (IFAHP) is applied to deal with uncertain data. The proposed approach employs multi-experts’ knowledge which helps to optimize the maintenance investments. A separator system in an offshore process facility platform is selected as a case study to demonstrate the application of the proposed methodology. A practical example in the separator system is surveyed and potential failures and Basic Events (BEs) are identified. Finally, a risk-based maintenance plan is provided for future safety investment analysis. The results indicate that the developed methodology estimates the risk more accurately, which enhances the reliability of future process operations.     

An intensive study on aerosol optical properties and affecting factors in Nanjing, China

The optical properties of aerosol as well as their impacting factors were investigated at a suburb site in Nanjing during autumn from 14 to 28 November 2012. More severe pollution was found together with lower visibility. The average scattering and absorption coefficients(B sca and B abs) were 375.7 ± 209.5 and 41.6 ± 18.7 Mm~(-1), respectively. Higher ?ngstr?m absorption and scattering exponents were attributed to the presence of more aged aerosol with smaller particles. Relative humidity(RH) was a key factor affecting aerosol extinction. High RH resulted in the impairment of visibility, with hygroscopic growth being independent of the dry extinction coefficient. The hygroscopic growth factor was 1.8 ± 1.2 with RH from 19% to 85%.Light absorption was enhanced by organic carbon(OC), elemental carbon(EC) and EC coatings,with contributions of 26%, 44% and 75%(532 nm), respectively. The B sca and B abs increased with increasing N_(100)(number concentration of PM_(2.5)with diameter above 100 nm), PM_1 surface concentration and PM_(2.5)mass concentration with good correlation.