内蒙古城镇体系空间结构分形特征分析

总结城镇体系空间结构的三种分形维数:聚集维数、网格维数和空间关联维数,并采用此方法计算内蒙古城镇体系空间结构的特征.结果表明:内蒙古城镇体系具有以"双核"城市为中心发展的分形特征,内蒙古地区89个城镇除了东部地区呼伦贝尔市、通辽市、赤峰市等3个市和锡林郭勒盟的部分城镇以外,其余西部地区的城镇主要围绕呼包二市为中心向四周...     

河西走廊城镇化与水资源效益的时空格局演变

干旱区城镇化的发展与水资源密切相关,实现两者的协调对区域可持续发展至关重要。以河西走廊20个县(区)为研究单元,构建城镇化与水资源效益的综合评价指标体系,使用熵值法赋权计算河西走廊2000、2005、2010、2013年的城镇化水平和水资源效益,运用探索性空间数据分析(ESDA)和协调发展模型,分析4个时间节点城镇化水平与水资源效益的集聚扩散状态及其时空格局和两者的协调性。结果表明:河西走廊城镇化水平的空间分布状态不稳定,变化显著;水资源效益呈现出分散的时空格局并保持相对稳定,且河西走廊及其3个内陆河流域的城镇化水平与水资源效益差异明显。同时,城镇化水平与水资源效益的协调发展水平逐步提高,协调发展类型主要为低和较低,且3大内陆河流域之间存在差异。     

甘肃省农业现代化水平区域差异的ESDA-GIS分析

基于ESDA-GIS的空间分析框架,利用甘肃省2005年87个县(市、区)的统计数据,对其农业现代化水平总体和局部空间差异格局进行了研究。首先对统计数据进行了概括性因子分析,抽取的投入、产出与社会发展因子值的频率分布都是偏态的。随后对县域农业现代化水平的空间结构进行了探索性分析,通过空间自相关测度分析得出:产出因子和社会发展因子的空间分布具有正相关性,呈现出空间集聚的特征;投入因子的空间相关特征不明显。最后将小城镇的局域空间自相关系数按县级行政单元进行聚类。研究表明:ESDA-GIS空间分析方法可以清楚地解释农业现代化水平的空间异质性问题,并且具有直观的可视化效果。     

基于ESDA的甘肃省县域经济空间差异分析

基于ESDA全局和局部空间自相关分析,利用甘肃省1992～2006年县域人均GDP数据,对甘肃省县域总体和局部空间差异的变化趋势、特征与成因进行了初步探索。结果表明:甘肃省经济空间自相关特性明显,经济发展水平相似的地区在空间上集聚分布,呈现出"哑铃"形的空间格局,即经济发达地区集中分布在河西地区,经济发展水平较低的地区集中分布在陇中、陇南、陇东地区。     

京津冀基本公共服务均等化水平测度及时空格局演变

通过构建基本公共服务均等化评价体系,采用集对分析模型对京津冀地区2006-2013年基本公共服务均等化水平进行了测度,并对其时空格局演变特征进行了分析.研究发现:1)时间序列上,2006年以来,京津冀地区基本公共服务均等化水平总体上呈现不断上升的趋势;市际间基本公共服务均等化水平具有明显的不均衡特征,随时间演进,市际间的相对差异与绝对差异均呈现缩小的趋势.2)空间格局上,京津冀地区基本公共服务水平总体呈现出由低水平不均衡格局向高水平均衡格局演进的趋势;基本公共服务空间格局呈现明显的中心外围结构,随时间演变,外围地区与中心基本公共服务梯度差异逐渐缩小;全局趋势上呈现出明显的自东北向西南衰减的梯度格局特征,与京津冀经济空间格局基本吻合.3)区域经济基础、城镇化发展水平、公共服务政策以及空间溢出效应对于公共服务水平具有重要影响.     

新型城镇化视角下的内蒙古城镇化发展水平综合评价研究

在充分挖掘新型城镇化的基本内涵、特征的基础上,从人口、经济、基础建设、居民生活质量、生态环境等层面构建了内蒙古自治区新型城镇化水平的评价指标体系,运用改进的熵值法和层次分析法,对内蒙古自治区12个盟市的新型城镇化综合水平和协调度进行评价与测算,在此基础上运用灰色关联度分析法,甄别新型城镇化各次系统和各指标的关系.研究结果:内蒙古各盟市之间新型城镇化综合发展水平差异比较大,新型城镇化综合发展水平高值区分布于”呼包鄂”地区、赤-通地区以及呼伦贝尔市等地区;内蒙古新型城镇化发展属于严重失调、中度失调和轻度失调区;新型城镇化发展受旧型城镇化影响较大,与人口和经济城镇化之间的关系较密切,今后的发展中注重建设和发展生态环境以及城乡一体化方面.     

近50a新疆沙尘暴冷热点的时空分布特征

利用1961-2010年新疆88个气象站的观测资料,运用空间自相关和热点分析方法,分析了近50a新疆沙尘暴冷热点的时空分布特征。结果显示:新疆沙尘暴具有明显的地区差异,空间分布具有较强的正空间自相关性,属于显著的空间集聚分布;冷热点空间演化格局逐渐稳定,呈现出不断缩小并集聚分布的趋势,冷点向新疆北部的博州和伊犁河谷集聚,热点位于塔克拉玛干沙漠边缘的和田及其周边地区,沙尘暴的防灾减灾工作需重点关注热点的时空变化。     

甘肃省区域经济差异及其发展对策研究

区域经济差异是区域宏观经济格局的量度,已成为科学研究和社会关注的焦点。本文在构建区域经济差异衡量指标体系的基础上,结合2005年甘肃省社会经济统计数据,以SPSS为工具,采用因子分析法,对甘肃省14个地级市(州)的经济发展水平进行了综合评价。采用聚类分析法,将全省划分为四个经济梯度区,分析了各梯度区发展状况、空间分布特点及面临的问题,在此基础上提出了区域协调发展的对策。     

基于GeoDA的新疆人均GDP空间关联性研究

空间依赖性和异质性是区域发展的内在属性和普遍现象,因此,空间关联性成为揭示空间分异规律的重要指标和有效手段。用地理空间分析方法和Geo DA软件,分析新疆2012年县域人均GDP空间分布关联性、人均GDP水平与城市化的空间关联性。结果表明:新疆人均GDP空间分布呈现正态分布。Moran's I达到0.4,在空间上呈现明显的集聚现象。其空间投影自南向北、自西向东、由里向外呈现聚集聚合正相关分布格局;北向性体现了南北疆发展条件的绝对差异,东向性反映了区域发展对交流通道或外向区位的依赖性,自然区位和基础设施是关键分异条件。LISA局域自相关分析发现,北疆热点地区集中在克拉玛依市、乌苏市、奎屯市和布克赛尔蒙古自治县等交通区位条件和资源富集程度较好的中心地区,而经济发达的乌昌经济圈与周围县市间差异较大并形成了明显的断层,沿边县市均属于落后、封闭的空间随机发展状态;南疆更明显,高值区高度集中于南疆交通枢纽库尔勒及其周边的塔北石油开发带上,南疆三地州及沿边县市大部分为低值区,贫困与贫穷具有空间一致性,说明新疆区域发展的同质性、同构性和趋同性特征。人均GDP与城市化的空间自相关分析也得出与此一致的结论。     

基于GIS的清代内蒙古地区城镇时空演变特征研究

清代是中国城镇迅猛发展和巨大变革的时期,奠定当今城市格局的基础.利用GIS软件和地统计方法对清代内蒙城镇发展做量化研究.结果表明:该地区城镇空间分布由长城关外察哈尔地区向东西两侧扩散,与内蒙五路驿传具有一定空间关联;城镇增长在时间上可识别四个阶段,增长初期(1723-1735)、加速期(1736-1820)、停滞期(1821-1874)和高速期(1874-1911),东部在内蒙与河北、辽宁、吉林三省交界处呈带状和点状集群特征,西部于土默特形成高密度核心.     

福寿螺配偶个体大小选择性初步观察

通过野外观察与实验研究,掌握了福寿螺的婚配体制及其配偶选择性规律。福寿螺与多数低等动物一样,其婚配属于乱交制,无固定配偶;雌螺对与其交配的雄螺个体大小没有选择性,而雄螺对雌螺的个体大小有选择性,倾向于与较大个的雌螺交配。     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

Localization of metabolic sites of action of herbicides

Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate ¹⁴C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides.     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere.     

Systems of designation of pathotypes of plant pathogens12

A variety of systems of designation has evolved to name pathotypes of plant pathogens. The systems were evaluated to determine those best suited for particular purposes. Virulence and avirulence/virulence formulae of pathotypes have advantage over the use of consecutive numbers or letters given in chronological order of pathotype discovery. As soon as pathotype information exceeds a certain level of complexity, mathematical codes are most advantageous, in particular two codes, octal notation and coded triplets. A more universal adoption of the most appropriate codes is recommended to ease communication and comparisons of results.     

Investigation of the Mode of Action of Nematode Neuropeptides

The neuropeptide AF2 has a complex set of actions on the dorsal muscle strip of Ascaris suum, including a potentiation of the acetylcholine-stimulated muscle contraction. Caffeine at 100 μm and 5 mm inhibited this potentiation, as did 100 μm theophylline in two out of six studies. The cyclic-AMP-potentiating compounds IBMX, dibutyryl cAMP and forskolin had no effect on the AF2-induced potentiation of the acetylcholine-stimulated muscle contraction. These preliminary data suggest that the potentiating action of AF2 is not mediated by a cAMP pathway.     

Mode of action of meturine

The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues.     

Mode of action of etoxazole

The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.     

Measures of durability of resistance

ABSTRACT Conventional models for the durability of resistant cultivars focus on the dynamics of the frequency of resistance genes. This leads to a definition of the durability of resistance as the time from introduction of the cultivar to the time when the frequency of the virulence gene reaches a preset threshold. It is questionable whether this is the most appropriate way to measure durability. Here we use a simple epidemiological model to link population dynamics and population genetics to compare three measures of durability: (i) the expected time until invasion of the virulent genotype, by mutation or immigration, and subsequent establishment of a population (T(invasion)); (ii) the virulence frequency related measure of the time for the virulent genotype to take-over the pathogen population ( T(take-over)); and (iii) the additional yield, measured by the additional number of uninfected host growth days (T(additional)). Specifically, we show how the measures of durability are affected by deployment and epidemiological parameters. We use a combination of numerical solution and analytical approximation of a model for the population dynamics of avirulent and virulent genotypes of a pathogen growing in dynamically changing populations of resistant and susceptible cultivars. The three measures of durability are compared. Some consequences of the results for durable resistance in multilines and mixtures and the regional deployment of resistant cultivars are discussed.