农药残留定量预测的数学方法研究

目前国内外关于农药降解规律的数学模型研究中,均是用一元函数来描述农药的降解规律,即把农药的残留量只看作是时间的函数,而农药降解还与初始用药量、光照时间、温度、降雨量等因素有密切关系,因此描述农药的降解规律的数学模型应是多元函数,本文应用函数逼近理论给出了农药降解规律的二元函数模型。应用这种函数模型揭示农药的降解规律是有一定实际意义的。     

鸟类鸣声行为对其物种分化和新种形成影响

鸟声和鸟类的形态特征一样,具有物种的特异性,在鸟类分类和野外识别方面是有意义的,从生物种的基本概念出发,新种的形成有赖于两个亲缘种群间不能相互婚配和繁殖隔离的产生。鸟类主要的有关特征是在配对形成过程中的听觉和视觉特征,如果出现鸣声特征的差异,而且这种差异已经超出了种间“语言通讯”的变化范围,那么它就有可能与群内其它异笥无法配对,从而被排除到该种群或种的范围之外,然而鸣禽的鸣唱有时在不同种群间变化很大,而在同一种群内比较稳定,从而形成种群的方言,在方言种群之间,如果长期隔离,就会在种群之间形成障碍乃至遗传上的隔离,从而使种群间失去了相互配偶的机会,新的亚种或种可能由此形成,文章最后假设出了基于鸣声行为的鸟类新种形成机理图解。     

METAMODELS AND PHYLOGENETIC REPLICATION: A SYSTEMATIC APPROACH TO THE EVOLUTION OF DEVELOPMENTAL PATHWAYS

Molecular genetic analysis of phenotypic variation has revealed many examples of evolutionary change in the developmental pathways that control plant and animal morphology. A major challenge is to integrate the information from diverse organisms and traits to understand the general patterns of developmental evolution. This integration can be facilitated by evolutionary metamodels—traits that have undergone multiple independent changes in different species and whose development is controlled by well-studied regulatory pathways. The metamodel approach provides the comparative equivalent of experimental replication, allowing us to test whether the evolution of each developmental pathway follows a consistent pattern, and whether different pathways are predisposed to different modes of evolution by their intrinsic organization. A review of several metamodels suggests that the structure of developmental pathways may bias the genetic basis of phenotypic evolution, and highlights phylogenetic replication as a value-added approach that produces deeper insights into the mechanisms of evolution than single-species analyses.     

ASSESSMENT OF BIVALVE INTRACELLULAR DIGESTION BASED ON DIRECT MEASUREMENTS

Two methods of studying intracellular digestive state in bivalvemolluscs, (1) the subjective tubule grading technique and (2)an alternative method based on measurements of digestive tubuleand luminal widths, were compared using data from a starvation/feedingexperiment on the quahog, Mercenaria mercenaria (L.). Measurementsof digestive cell heights or lumen widths could not be directlycompared due to differences in tubule widths within and betweenindividuals (range = 56.6 to 77.4 µm; X = 63.0; SD 4.8(µm) which were unrelated to quahog length. Instead, themean proportion of the tubule width (MPTW) covered by digestivecell cytoplasm was used for comparisons between samples of animals.MPTW covaried directly with the subjectively established proportionof Type II tubules (r = 0.882). The inclusion of data from obliquesections of digestive tubules did not unduly affect statisticalresults . Of 4 sampling schemes compared, a systematic samplingscheme in which measurements were made on only one digestivegland tubule within an area containing a cluster of similartubule types, was shown to be best. ¹Contribution No. 105, Marine Science Institute, NortheasternUniversity, Nahant, MA., 01908 ²Current address: New England Aquarium, Central Wharf, Boston,MA, 02110 USA (Received 28 September 1981;     

基于微流控芯片的鲑科鱼类单核苷酸多态性分型系统构建

为开发针对大规模样本、低通量位点的单核苷酸多态性(Single nucleotide polymorphism, SNP)分型技术,研究依据虹鳟高通量SNP芯片检测鲑科4个属不同物种群体样本的结果,筛选获得了96个高质量共享多态性位点,应用Fluidigm 96.96微流控动态芯片平台,构建了用于鲑科物种增殖放流个体识别的SNP分型系统。以细鳞鲑为例评估芯片分型结果可靠性,分型成功率为98.63%,与Affymetrix高通量芯片分型一致性达到97.92%。基于该芯片分型结果,使用CERVUS 3.0.7软件对96尾细鳞鲑子代样本及其候选亲本和干扰亲本进行亲权鉴定,结果能够准确重现复杂家系的真实系谱,在用于单亲本亲权鉴定时,第一亲本非排除率(Nonexclusion probability for first parent, NE-1P)为4.362×10^–4,用于双亲本亲权鉴定时,双亲非排除率(Nonexclusion probability for parent pair, NE-PP)为6.538×10^–12,完全满足增殖放流回捕个体分...     

A SYSTEMATIC STUDY OF GIGAR-TINACEAE FROM PACIFIC NORTH AMERICA BASED ON MOLECULAR AND MORPHOLOGICAL EVIDENCE

Frequent episodes of algal-related tastes and odors (T & O) in drinking waters in metropolitan Phoenix, Arizona prompted initiation of a three-year project in July 1999 to investigate the occurrence of T & O metabolites and to develop a comprehensive management strategy to reduce the problems in drinking water supplies in arid environments. Two metabolites, 2-methylisoborneol (MIB) and geosmin, have been identified as compounds responsible for the earthy-musty tastes and odors in water supplies. Both were detected in the water supply system, including source rivers, reservoirs, canal delivery system and water treatment plants. Higher concentrations of MIB and geosmin occurred in distribution canals than in the upstream reservoirs indicating that significant production of the T & O compounds occurs within the canal system. A baseline-monitoring program has been established for the complex water supply system, with special emphasis on the canal system. Efforts are underway to investigate possible correlations between physical/chemical parameters, algal composition and biomass, with the occurrence of MIB and geosmin. In addition, several physical and chemical treatments are planned for the canal system to reduce algal growth and related MIB and geosmin concentrations.     

面向对象的冲压件特征建模研究

应用面向对象的表达策略,对冲压零件的特征及其联系进行了描述,并建立了在语义、结构上有统一形式的冲压件模型.这种冲压件的定义方法不仅有利于设计,而且便于进行冲压件的可制造性评价,更重要的是为后续的冲压工艺设计提供了较为完备的工艺信息.     

基于螺旋区随机堆积的RNA二级结构预测

提出了基于螺旋区随机堆积的ＲＮＡ二级结构预测算法,包括三个步骤：１．根据螺旋区定义,找出所有可能螺旋区;２进行螺旋区随机堆积,形成一定数目的ＲＮＡ二级结构;３．统计处理,推测ＲＮＡ可能折叠方式。最后以酵母Ｐｈｅ－ｔＲＮＡ为例来说明方法的可行性。     

THE DETERMINATION OF GENETIC COVARIANCES AND PREDICTION OF EVOLUTIONARY TRAJECTORIES BASED ON A GENETIC CORRELATION MATRIX

There is much interest in measuring selection, quantifying evolutionary constraints, and predicting evolutionary trajectories in natural populations. For these studies, genetic (co)variances among fitness traits play a central role. We explore the conditions that determine the sign of genetic covariances and demonstrate a critical role of selection in shaping genetic covariances. In addition, we show that genetic covariance matrices rather than genetic correlation matrices should be characterized and studied in order to infer genetic basis of population differentiation and/or to predict evolutionary trajectories.     

A PCR-MPN BASED QUANTITATIVE APPROACH TO ENUMERATE NITRIFYING BACTERIA IN ZEOPONIC SUBSTRATES

Self-sustaining, regenerative life-support systems are required for long duration missions to the Moon and Mars. Improved activity of nitrifying bacteria to convert NH₄⁺ to NO₃^- has been shown to promote plant growth in zeoponic substrates. Due to physiological characteristics, such as slow growth and low yield, nitrifying bacteria are not easily enumerated by traditional microbiological techniques. A method for rapid detection and enumeration of a commercial inoculum of nitrifying bacteria in a zeoponic substrate was developed using a polymerase chain reaction (PCR)-most probable number (MPN) approach. Samples from four-week laboratory incubation studies were processed to extract their total microbial community DNA and the sequences specific to 16s rRNA of Nitrobacter spp. were PCR amplified. The detection limit of the methodology was 2,000 Nitrobacter cells per assay. The quantitative assay demonstrated that the zeoponic substrate was capable of supporting 10⁵ to 10⁶ MPN Nitrobacter cells per gram of substrate. The PCR-MPN method can be an effective and rapid approach to enumerate nitrifying bacteria in zeoponic substrates.     

中国千金藤属分类梗概

在《中国千金藤属初步研究》(载Acta Phytotaxonomica Sinica 16:10.1978)一文中,作者建议将我国产千金藤属植物分为4群(Group)。现在我们仍然认为该文对千金藤属植物的处理基本上是正确的,划分的4个群也是比较自然的植物群。本文将在这一基础上对这属植物的演变趋势提出一些初步的看法。同时根据对其演变趋势的分析,将该文所建议的4个植物群作适当的调整,以期较为客观地反映群间亲缘关系的远近和进化水平的差异。     

水生植物系统学中若干问题的探讨

水生植物对其特殊生境的适应,使得某些普遍存在于植物系统学中的问题在水生植物系统学领域里表现得更为突出。近年来,作者采用细胞学、形态解剖学、生态学、植物地理学以及电镜扫描,凝胶电泳等方法和技术对水生植物从细胞到群落的各个层次进行了综合性系统研究;分析了水生植物的1.环境饰变、遗传多态及由此产生的分类问题;2.水生植物的地理分布及生境特点;3.与分类有关的繁殖生物学问题;4.种间关系等若干问题的探讨。