台湾中部地区短延时降雨强度初步探讨

台湾地区在经历1999年的921地震后,山坡地土体松动严重,仅仅短延时的降雨即有机会引起土石流的发生,而近年微小的降雨条件下即有可能触动土石流发生,因此将台湾中部地区14个测站所测得的台风降雨资料,依照台风降雨强度进行水文频率分析,分析方法采用对数常态分布法、极端值第一类分布法、皮尔逊第三类分布法及对数皮尔逊第三类分布法等4种方法,计算短延时重现期距并绘成降雨强度-延时-频率之分析曲线,再整合各区域土石流潜势溪流的分布情况,分析台风降雨对台湾中部地区所造成之影响.     

Analysis of Sediment Source of Watershed in Western Shanxi of the Loess Plateau

1 INTRODUCTIONThe Loess Plateau is the most drastic soil erosion regionin China, with the most severe water erosion. Thedistribution of types and intensity of erosion not onlyhave regional diversity but also have perpendicularvariation. In the small watershed, there are differencesin erosion characters among its upper, middle and lowerreaches. It is very significant for taking rationalmeasures of soil and water conservation and forpreventing soil and water loss to analyze the relationbe…     

Strategic Trend of Chinese Urban Forestry Development

1 STRATEGY BACKGROUND1.1 Quickening of Urbanization ProcessSince the reform and opening-up in China in 1978,economic community developed rapidly. By the endof 2003, GDP has exceeded $1 000 billion. With therapid development of Chinese economy, residentialmode focusing on rural population is now changing,urbanization process is quickening, traditional cityscale is expanding into metropolis (Tianjin, Xi’an,Chengdu, Chongqing, etc.) or super cities (Beijing,Shanghai, Guangzhou, etc.…     

Construction of cDNA Library from Populus euphratica

1 Introduction Populus euphratica is a salt tolerant tree species, which is mainly distributed in the desert regions in northwest China (Wei 1993). Moreover, it is the only large tree species, which can survive and develop into forest in these arid and saline-alkali areas. P. euphratica forest plays a very important role in restraining the expansion of desert, maintaining ecological environment in west China, protecting the biological diversity and raising the local people抯 living standard…     

Ultrastructural and Extracellular Protein Changes in Cell Suspension Cultures of Populus euphratica Associated with Low Temperature-induced Cold Acclimation

Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of-17.5 ℃) in cell suspension at 4-5 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of-12.5 ℃ in nonacclimated cells to LT50 of-17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed.     

Analysis on Schistosomiasis Occurrence And Preventive Measures in Three Gorges Reservoir

Recently, due to more flooding, schistosomiasis is in expanding tendency in some areas. With Three Gorges Engineering progress, schistosomiasis will occurr potentially in Three Gorges reservoir. In order to control the disease, some methods must be applied, e.g. chemicals, biological measures. To some extent every way has its specific effect. However, the vital way is improving the environment and reducing the amount of snails. One of the effective ways is conducting forestry ecological engineering that focuses on snail control and schistosomiasis prevention. The practical ways cover such as pollution controlling, ditches surface hardening. Especially for water-level-fluctuation zone, conducting forestry ecological engineering to improve environment to prevent snails＇ propagation is significant and vital. By operating the project environment could be greatly improved and people＇s living conditions would be bettered.     

北京地区节水型屋顶绿化植物配置及养护

节水型屋顶绿化是北京地区增加城市绿化面积,改善城市生态环境的重要手段。本文通过查阅文献、实地调查和总结分析,从植物生长的条件和配置原则出发,归纳了北京地区屋顶绿化常用的植物材料,提出适合北京地区节水型屋顶绿化的植物选择原则,并根据这些原则,提出了推荐北京地区节水型屋顶绿化使用的乔木植物油松(Pinustabulaeformis)等15种、灌木植物大叶黄杨(Buxusmegistophylla)等27种、地被植物景天类(Sedum spectabilis)等13种,推荐了喷灌、滴灌和渗灌等3种可用于屋顶绿化的节水灌溉技术,并简要介绍了屋顶绿化的修剪要求,为北京地区节水型屋顶绿化的推广提供了理论依据和技术支持。     

林业常用16种杀虫剂对赤眼蜂的急性毒性和安全性评价

采用管测药膜法测定了16种杀虫剂对松毛虫赤眼蜂的急性毒性,并进行安全性评价。急性毒性测定的结果表明:苏云金杆菌、球孢白僵菌、灭幼脲、杀铃脲、甲氧虫酰肼、苦皮藤素对松毛虫赤眼蜂毒性较低,其LR50均高于9.16×10-3mg·cm-2,为低风险性药剂。甲氨基阿维菌素苯甲酸盐、啶虫脒、噻虫啉、辛硫磷、高效氯氟氰菊酯、吡虫啉、氟虫腈和阿维菌素对松毛虫赤眼蜂毒性较高,其LR50分别是2.28×10-4、9.81×10-5、5.23×10-5、2.43×10-5、1.39×10-5、4.33×10-6、2.10×10-6和1.92×10-6mg·cm-2,安全性评价均为高风险性和极高风险性。敌敌畏对松毛虫赤眼蜂的毒性最高,其LR50是1.11×10-6mg·cm-2;其次为虫螨腈,LR50是1.31×10-6mg·cm-2,对松毛虫赤眼蜂伤害均较严重。     

热应激诱导大鼠小肠昼夜节律基因差异表达的研究Heat stress induced different circadian rhythms genes expression in rat small intestine

采用石蜡切片H.E染色观察热应激大鼠小肠形态学变化，利用Realtime-PCR技术对小肠中昼夜节律相关基因的表达进行研究。结果：大鼠小肠上皮出现严重损伤，肠黏膜绒毛顶端上皮细胞脱落，固有层裸露；热应激导致Per2和DBP基因瞬时表达极大升高，节律性受到严重影响，Bmal1基因瞬时表达差异不明显，其mRNA表达量峰值后移。To observe the morphological changes in response to heat stress, rat small intestine was embedded in paraffin, sectioned in transverse and stained with hematoxylin and eosin. The expressions of genes related to circadian rhythms were detected by Realtime-PCR. Results: heat stress resulted in profound damage to the epithelium of rat small intestine, the villus tips shed into lumen and the lamina propria was exposed; the gene expressions of Per2 and DBP were significantly increased so after the heat stress and the rhythms was affected; heat stress could not induce Bmal1 different expression immediatley, whereas, the peak of mRNA was hysteretic.