Landscape-ecological mapping of the Netherlands

The Landscape-ecological Mapping of the Netherlands project (LMN project) started in 1983 with the aim of establishing a landscape-ecological database for use in developing and evaluating national land-use plans. The project, working with grid cells of 1 km², has four working objectives: a) development of mapping potential for basic landscape-ecological data, b) assessment of susceptibility to interventions, c) evaluation of significance for nature conservation and d) production of vulnerability maps, as a combination of susceptibility and significance. In addition to information on soil, groundwater, ecotopes, flora and fauna, the database also incorporates information on physiographical features and entire landscapes. The resulting database is a geographic information system (GIS). This article describes the second phase of the project (1985–1989), covering the Randstad area, and focusses on the methods and the applications potential of the database.     

供水工程影响下中国北方地区耕地后备资源开发潜力

灌溉水源是北方地区耕地后备资源能否有效开发的关键。当前,中国正在推动国家水网工程规划建设,为北方地区耕地后备资源开发提供了新的机遇。在以往研究基础上,该研究考虑北方地区已建、在建及规划的供水工程,基于自然适宜、利用高效、发展稳定三方面评价准则,结合三维魔方空间分类方法,开展了雨养情景和供水灌溉情景下耕地后备资源开发潜力分析。结果表明：雨养农业情景下,北方地区勉强适宜（Ⅱ级）、中度（Ⅲ级）和高度（Ⅳ级）适宜的耕地后备资源面积分别为2.9万、1.0万和0.6万km²。灌溉农业情景下,耕地后备资源面积明显增加,勉强适宜（Ⅱ级）、中度（Ⅲ级）和高度（Ⅳ级）适宜的耕地后备资源面积将分别达到5.4万、7.6万和6.5万km²,主要集中于新疆、内蒙古和甘肃3省（自治区）。该研究结果可为中国耕地后备资源开发利用及国家水网工程效益发挥提供参考。     

《蒙古秘史》中的野生食用植物研究

经考证,在《蒙古秘史》中的植物古蒙古名称中,有山荆子、稠李、地榆、鹅绒委陵菜、葱、山韭、山丹和野韭等８种野生食用植物。植物区系及地理分布的研究表明,这些植物在十二世纪蒙古人所采集的地点,即现在的蒙古国肯特山脉地区仍有广泛分布。从民族植物学的研究看,它们在蒙古族民间被用于代粮、野菜、茶用、药用和调味品,比过去的利用有了很大的发展,已成为独特的植物利用文化。本文不仅对蒙古学研究能够提供可靠的依据,而且对寻找新的食用植物种类及其开发利用研究也提供了一些基本资料。     

强化“现代科技革命与马克思主义”课程教学中的三个主要环节

通过对博士研究生特点的综合分析,在教学实践中强化三个主要环节,探索了适合博士生特点,反映课程要求的教学方法。     

计算机计算含未知量元素行列式的“保值回跳”法

本文探讨了用计算机计算含未知量元素行列式的方法与途径,提出了“保值回跳”的思想。并提供了以该思想为基础而编制的空间桁架结构位移响应关于截面设计变量显式表达式程序计算的若干算例。     

光敏核不育水稻选育与利用的几个问题讨论

对现有光敏核不育材料进行了分类,分为４种遗传类型;其中,温光弱感到光敏核不育系是最为理 想的遗传工具,并就其选育途径和选择“粳不籼恢”繁殖制种技术体系进行了论证．     

An investigation of uncertainty in field habitat mapping and the implications for detecting land cover change

Land cover data for landscape ecological studies are frequently obtained by field survey. In the United Kingdom, temporally separated field surveys have been used to identify the locations and magnitudes of recent changes in land cover. However, such map data contain errors which may seriously hinder the identification of land cover change and the extent and locations of rare landscape features. This paper investigates the extent of the differences between two sets of maps derived from field surveys within the Northumberland National Park in 1991 and 1992. The method used in each survey was the Phase 1 approach of the Nature Conservancy Council of Great Britain. Differences between maps were greatest for the land cover types with the smallest areas. Overall spatial correspondence between maps was found to be only 44.4%. A maximum of 14.4% of the total area surveyed was found to have undergone genuine land cover change. The remaining discrepancies, equivalent to 41.2% of the total survey area, were attributed primarily to differences of land cover interpretation between surveyors (classification error). Differences in boundary locations (positional error) were also noted, but were found to be a relatively minor source of error. The implications for the detection of land cover change and habitat mapping are discussed.     

小水电科技发展领域的系统分析

该文用层次分析法(AHP)和德尔菲法(Delphi)相结合的系统分析法,对江西省上饶地区小水电科技发展领域分析模型作了探索,提出了小水电科技发展领域的优先度及重点,为“八五”、“九五”小水电科技规划的制定提供了依据,同时也为水利水电同行在科技规划中提供一点参考。     

Sexual compatibility types of Bremia lactucae isolates originating from Lactuca serriola

Results are given on the occurrence of sexual compatibility types of seven isolates ofBremia lactucae originating fromLactuca serriola (prickly lettuce). It is concluded that the isolates studied are heterothallic. Both compatibility types (B1 en B2) were determined, but type B2 was prevalent. Sexual recombination ofB. lactucae isolates originating from wild and cultivated lettuce may occur.Samenvatting Zeven isolaten vanBremia lactucae, afkomstig vanLactuca serriola in Tsjechoslowakije, zijn onderzocht op hun sexuele compatibiliteitstype door ze te combineren met Nederlandse fysio's vanB. lactucae, afkomstig van cultuursla (L. sativa), waarvan het compatibiliteitstype (B1 of B2) bekend is. Alle isolaten vanL. serriola bleken heterothallisch te zijn, waarbij type B2 meer werd aangetroffen dan type B1. Sexuele recombinatie vanBremia-isolaten van wildeLactuca-soorten en cultuursla blijkt goed mogelijk te zijn.     

The metabolism of R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene] in rat hepatocyte suspensions

The metabolism of R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene] by rat hepatocytes has been analyzed and compared with that of juvenile hormone I [methyl-(E,E)-cis-10,11-epoxy-7-ethyl-3,11-dimethyl-2,6-tridecadienoate] under identical conditions. The metabolism of R-20458 is characterized by the predominance of NADPH-dependent cytochrome P-450 and epoxide hydrolase reactions; whereas, JH I is metabolized mainly by carboxylesterase, epoxide hydrolase, and glutathione S-transferases. The metabolites of R-20458 have been shown to correspond to (E)-6,7-epoxy-1-(4-hydroxyethylphenoxy)-3,7-dimethyl-2-octene; (E)-6,7-epoxy-1-(4-acetylphenoxy)-3,7-dimethyl-2-octene; (E)-6,7-dihydroxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene; and, (E)-6,7-dihydroxy-1-(4-acetylphenoxy)-3,7-dimethyl-2-octene. The production of the α-hydroxyethyl, p-acetylphenoxy, and acetylphenoxy-6,7-diol metabolites is markedly inhibited by SKF 525-A. No dramatic effects are produced by diethylmaleate and 1,2-epoxy-3,3,3-trichloropropane.