岷江上游茂县半干旱河谷灌丛优势种间关系的研究

采用２×２列联表，通过方差分析、Ｘ２检验、Ｏｃｈｉｎｉ关联指数和Ｐｅａｒｓｏｎ积矩相关系数，分别对岷江上游茂县半干旱柯谷灌丛的１０个主要优势种的种间关联和种间协变进行了定量分析．研究结果表明：茂县半干旱河谷灌丛的优势种间关系较复杂．多物种间里显著的复合正相关关系，４５个种对中的７个种对具有显著的正关联，其关联程度较高（Ｏｃｈｉａｉ指数为０．６４５～０．８５８），这些关联的种对分别对环境的要求相同；５个种对存在显著的正协变，它们都是非显著关联的种对，表明在某一具体的植被类型中，种间关联与协变并无明显的内在联系．小角柱花（Ｃｅｒａｔｏｓｔｉｇｍａｍｉｎｕｓ）与其它优势种间的关联性最广泛，而刺族花（Ｃｏｎｖｏｌｖｕｌｕｓｔｒａｇａｃａｎｔｈｏｉｄｅｓ）则无显著的关联和协变，是一个相对独立的成分．     

中亚热带次生林成林规律及经营技术研究——Ⅰ.次生林环境背景分析与类型划分

本文分析了湖南省中亚热带次生林优势种群间的联结和环境梯度。通过研究,将全省次生林划分为8大类型即暖性针叶林、温性针叶林、干热性常绿阔叶林、干暖性常绿阔叶林、暖湿性常绿阔叶林、温湿性常绿阔叶林、暖性落叶阔叶林和温性落叶阔叶林等。     

导弹用材料环境适应性数据库设计

目的 针对材料工艺师需要系统整合导弹环境适应性信息的手段、分析数据变化规律的工具、网络共享的平台,设计并开发导弹用材料环境适应性数据库。方法 数据库软件采用J2ee体系架构搭建,设计虚拟导弹数字化模型,通过建立大量的数据关联,将导弹基本结构信息、导弹整机失效信息、弹用材料基本性能信息、环境适应性信息和环境信息五大类信息整合为一体,供导弹模型调用。设计曲线绘制算法,采用ActionScript脚本语言编程,实现数据规律动态绘制,采用跨库关联建立数据关联查询和数据对比分析。结果 用户可通过鼠标操作,拆分和组装导弹模型,全方位观察导弹的构成。利用导弹模型整合的五大类环境适应性信息,直观反映导弹的构成和材料应用情况。软件能够查询导弹的故障模式、弹用材料环境适应性信息等,跨库关联则增强了的数据对比性。结论 该数据库已经通过软件测评并上线运行,为导弹多个型号的选材和防护设计工作提供帮助,用户反映良好。     

基于关联规则的跑道着陆事件演化网络构建研究*

为了提高航空运输系统安全性,针对航空器着陆过程中冲偏出和重着陆事件的关联机理开展研究。以84起跑道着陆事故调查报告为样本,利用Python分词工具提取风险因素并建立跑道着陆事件数据集,应用Apriori算法挖掘风险因素间关联规则,基于复杂网络理论构建该类事件演化网络,分析社团结构和拓扑特征。研究结果表明:本文所构建的网络密度为0.143,网络较为紧密,风险因素间强关联;网络社团结构显著,符合飞行操纵、运行状态、运行环境、不利条件的分类特点;网络关键节点“航线训练”、“接地速度大”综合值分别为0.599 8、0.589 0。研究结果可为飞行安全研究提供新思路。     

株洲市城郊天然植物群落调查研究

植物群落是植物在自然因素综合作用下形成的一个有机体，是植物群体发展的自然属性．在不同的生态环境条件下产生了不同的群落类型．地处中亚热带丘陵地的株洲，地带性典型植物群落是常绿阔叶林，是以各类常绿树种为优势的植被类型．但是随着历史变迁，人类频繁活动，此类群落已不复存在，以人工群落和次生群落取而代之，其主要群落类型有青冈栎群落、石栎群落、苦槠、青冈栎群落、樟树群落、冬青群落、山杜英群落等12种．园林绿化作为人工群落，其园林植物选择和配置，设计建造人工群落都要遵循天然群落发生、发展规律及模拟其结构特征才能实现园林绿化低成本、高效益、高生产力、高生物量的总体目标．因此，开展对城郊区现有天然林的调查是非常必要的．其结果直接用于城市绿地系统规划和人工模拟地带性植物造景．     

Quantifying the influence of the cultivated plant species on the occurrence of carabid beetles within certain species using contingency table analysis

The influence of the cultivated plant stand, subject to the timing of sampling, on the occurrence of selected carabid species is investigated for three years running. Due to the nominal character of the factors (cultivar, timing, carabid species and year) we used log-linear models of four dimensional contingency tables under certain hypotheses of independence. A coefficient of contingency is calculated for characterizing the partial association between two factors respectively. The difference in G 2 's between two nested models is used to test if there are differences between the three years concerning the strength of partial association between the number of beetles in the selected species and the cultivar or the sampling time respectively.     

Interspecific relationships of the midday gerbil (Meriones meridianus Pall., 1773) and tamarisk gerbil (M. tamariscinus Pall., 1773) in pasture ecosystems of the Kalmyk Republic

Studies performed in the southern Kalmyk Republic from 1993 to 2005 have shown that the midday and tamarisk gerbils are similar in their biotopic distribution and that their preferences for certain habitats depend on specific features of feeding. Individual home ranges of both species overlap, and the patterns of their daily activity are synchronous. These facts suggest that there is no interference competition between the midday and tamarisk gerbils in pastures of the southern Kalmyk Republic.     

Short‐chain fatty acids affect cell‐association and invasion of HEp‐2 cells by Salmonella typhimurium

Abstract

This study demonstrates that the growth of S. typhimurium in Luria Bertani broth supplemented with acetate, propionate, butyrate, or a mixture of the three SCFA, affected cell‐association and the ability to invade cultured HEp‐2 cells. Cell‐association and invasion was determined after growth for 4 h of growth in the presence of the SCFA at pH 6 and 7. The results suggest that the growth rate of the culture may have affected cell‐association and invasion since accompanying the significant decrease in growth rate in the presence of SCFA at pH 6 was a decrease in cell‐association and invasion. However, the results also suggest that the individual SCFA may play a role in modulating cell‐association and the invasion phenotype and the regulation of cell‐association and invasion by the SCFA was dependent on the concentration and the pH of the medium. Although the growth rates were similar for S. typhimurium in the SCFA mixture, butyrate (100 mM) and propionate (50 mM) at pH 6, differences in cell‐association and invasion were observed among these cultures. Also, at pH 7, differences were observed among the SCFA treatments even though the growth rates were similar.     

岷江上游祁连山圆柏群落优势种群间的联结性

应用方差分析X^2-测验、点相关系数和Jaccard指数等技术对岷江上游祁连山圆柏群落中12个优势种群的种间联结性进行了研究．结果表明：①12个优势种群在总体上呈显著的负联结，这跟该群落目前所处的演替状态及十扰造成的环境不稳定有密切的关系．②在66个种对中，经X^2-检验联结性达到显著的有4对，即西南樱桃与多叶飞蓬，腋花马先蒿和甘川紫菀，黄总花与银莲花，多叶飞蓬和甘川紫菀．这4个种对显著的联结性跟物种本身的生物学习性有关．③金花小檗、川西锦鸡儿是该群落逆行演替的代表种，由二者之一参与形成的各种对联结性最弱，这两种植物与群落中的其它物种形成较强的联系，还需要一个过程．图1表5参36