二十四节气与气传致敏花粉及呼吸道过敏相关性研究     

苏恺  程甜甜  田露芳  郑青  张逸伦  林海韵  王班  吴谦  冷蓓峥  王莲芸 《上海交通大学学报(农业科学版)》2019,(5):47-52

为研究上海西南部气传致敏花粉的全年变化规律和它与呼吸道过敏性疾病发病之间的关系,全年共收集58科各类花粉(3 605个/cm~2);以及对应日期门诊就诊的过敏性疾病患者(4 482人);以二十四节气为时间划分节点,对13个空气中有花粉漂浮的节气数据进行统计分析。结果表明:在春季的清明和谷雨花粉数量达到高峰,而在秋季花粉自白露后显著增加;过敏性鼻炎患者的数量与一定范围内的花粉数量呈现明显的相关性(r=0.410,P=0.033);花粉数量与不同性别的过敏性鼻炎患者数量间未见显著性差异(P0.05);但是,花粉数量与过敏性鼻炎患者年龄间有显著性差异。总之,在清明、谷雨和白露等节气中,空气中飘散的气传致敏花粉数量较多,门诊过敏性鼻炎就诊患者数也相应增多,并且以中青年为主。  相似文献   

基于不同环境下的河南省典型区域土壤田间持水量研究   总被引：2，自引：0，他引：2  

罗清元  杨丹  刘丽娜  郭恒亮 《节水灌溉》2019,(6):35-38,42

土壤田间持水量是衡量土壤墒情和干旱程度的一个重要指标。由于田间持水量的测定环境不同,如季节、环境等因素,可能导致相同区域的土壤其测定结果也不相同。通过颗粒分析实验,确定了全省122处人工墒情站的土壤类型,并从中选取了3个不同土壤类型的站点开展不同季节不同环境下的田间持水量试验。结果表明:①从全省范围来看,河南省的土壤以壤土类型为主,在防汛抗旱时要充分考虑该种土壤类型的蓄水特性;②通过分析试验数据可以得到,其田间持水量与干容重呈现线性反比关系;③3种土壤在不同的季节及实验室温度环境下,田间持水量测定结果差别不大,因此可以得出田间持水量基本不受温度季节的影响的结论。  相似文献   

Application of a Particle Swarm Optimization Algorithm in Truss Structure Optimal Design     

LI Feng  TANG He sheng  XUE Song tao  WANG Yong  CHEN Rong 《保鲜与加工》2009,(1):7-12

The particle swarm optimization (PSO) algorithm developed in recent years is a stochastic optimization algorithm based on swarm intelligence. It possesses advantages such as being a simple concept, ease of implementation and low resource occupation. The PSO algorithm was adopted to solve the problem of size optimization of truss structures with stress and displacement constraints. We present the basic principle of the original PSO algorithm in detail, and then introduce a constriction coefficient to modify it. Moreover, reasonable values of the coefficients are proposed for the modified PSO algorithm. Several classical problems are solved using the modified PSO algorithm, and the results compared with those using traditional optimization algorithms and genetic algorithms. Numerical results show that the modified PSO algorithm has good convergence and stability, and can be applied to the size optimization of truss structures.  相似文献   

Elastic deformable particle model in discrete element method     

WEN Tong  LEI Jie  PEI Chun lei 《保鲜与加工》2009,(7):743-746

A polygon particle model with discrete element method（DEM） is developed based on the Hooke’s law, in which the geometry change caused by the elastic deformation and features of material can be taken into account. A DEM programme is developed based on the proposed model and collision processes of elastic particles is studied with finite element method(FEM) and DEM. Comparing the result of DEM with that of FEM. When dealing with the problem of particles contact, the real deformation and the contact force variation of the particles can be presented more accurately with elastic deformable particle model, compared with that from traditional rigid particle model.  相似文献   

家蚕细胞质型多角体病毒的核酸结合蛋白   总被引：2，自引：0，他引：2  

钟伯雄 《蚕业科学》2001,27(3):193-196

采用Northwestern分子杂交方法 ,研究了家蚕细胞质型多角体病毒 (BmCPV)结构蛋白质的功能 ,结果证明VP1、VP3和VP4具有与核酸结合的能力 ,暗示了VP1可能是依赖于RNA的RNA聚合酶 ,在病毒核酸复制中起作用 ;VP4可能是核酸结合蛋白 ,在病毒粒子的复制包装过程中有结合核酸、促成完整病毒粒子形成的作用 ,可能是BmCPV病毒复制包装中的关键蛋白  相似文献   

杂交王鸽种鸽颗粒料的研究     

吴红  陈启康  周俊芳  沙文锋  顾拥建  梁志彬 《天津农学院学报》2002,9(2):17-20

选用 90对健康肉用种鸽,分为A、B、C、D试验组和E对照组共 5组,每组 18对种鸽。试验组饲料的粗蛋白(CP)水平分别为 16.16 %、14.2 2 %、14.2 9%、16.18%,代谢能(ME)分别为 11.85KJ/g、11.82KJ/g、12.5 2KJ/g、12.5 1KJ/g的颗粒料。对照组饲料是粗蛋白含量为11.79%,代谢能为 13.31KJ/g的原粮。进行种鸽颗粒料筛选及与原粮的对比试验。结果表明,30日龄乳鸽体重A、B、C、D 4组分别为 5 17.0 0± 4 1.4 3、5 0 5.16± 34.16、5 0 6.6 7± 39.5 6、4 97.6 8± 4 6.0 4 g,比对照组 4 70.0 0± 4 3.4 2g分别提高 10 %、7.4 %、7.8%、5.9%。A、B、C组与E组差异极显著(P <0.0 1),D与E组差异显著(P <0.0 5)。种鸽的受精率、孵化率各组差异不明显。种鸽生产周期A、B、C、D试验组分别比对照E组缩短 4.6 0、2.85、1.73、4.30d。A、D组与E对照组差异显著。表明粗蛋白为 16.16 %、代谢能为 11.85KJ/g的种鸽颗粒料效果最好,该颗粒料促进乳鸽生长发育,缩短种鸽生产周期,提高肉鸽种用价值。  相似文献   

荒漠藻固沙结皮试验研究初报   总被引：13，自引：2，他引：13  

闫德仁  杨俊平  安晓亮  任建民 《干旱区资源与环境》2004,18(5):147-150

本文利用跑道式培养池培养了已筛选的两个荒漠藻品种 ,并在野外进行了荒漠藻结皮人工接种效果的研究 ;探讨了荒漠藻固沙结皮的形成与植被发育的关系 ;提出了藻沙粒结皮是荒漠藻结皮的早期形式。进一步分析了荒漠藻固沙结皮综合固沙技术的关键问题  相似文献   

Disguising the Leaf Surface: The Use of Leaf Coatings for Plant Disease Control     

Dale R. Walters 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(3):255-260

The ability of fungal pathogens to develop resistance to fungicides and to overcome genetic resistance in their hosts, coupled with growing public concern for the environment, means that there is an urgent need for novel methods of disease control. The leaf surface provides the first barrier that fungi must overcome in order to gain access to the leaf, but it also provides chemical and physical cues that are necessary for the development of infection structures for many fungal pathogens. Film-forming polymers can coat the leaf surface, acting not just as an extra barrier to infection, but also disguising the cues necessary for germling development. Kaolin particle films can envelop the leaf in a hydrophobic particle film barrier that prevents spores or water from directly contacting the leaf surface and as a result, can suppress infection. Adhesion of fungal spores to the leaf surface, which is important to keep spores on the leaf surface and for appropriate development of the fungus on the leaf surface, can be inhibited, leading to reduced infection and lesion development. Polymer and particle films have been shown to provide disease control in the field, while research on agents that inhibit spore adhesion on leaf surfaces is still in its infancy. There is an urgent need for research on the practicality of using these novel methods under field conditions and on ways of integrating them into current crop protection programmes.  相似文献   

多脂鳞伞菌丝体多糖抗肿瘤活性研究   总被引：5，自引：0，他引：5  

赵永勋  李克颖  张跃华 《食用菌学报》2007,14(2):49-54

多脂鳞伞[Pholiota adiposa(Fr.)Quel.]菌丝体多糖溶液给S-180荷瘤小鼠连续灌胃10d后,测定对荷瘤小鼠抑瘤率、碳粒廓清指数、小鼠外周血肿瘤坏死因子(TNF-α)和白介素-2(IL-2)含量的影响。结果发现,多脂鳞伞菌丝体多糖对荷瘤小鼠肿瘤的抑瘤率为39.54%,并可提高小鼠碳粒廓清指数,血清中IL-2和TNF-α的含量也明显提高。结果提示,多脂鳞伞菌丝体多糖抑制荷瘤小鼠的肿瘤生长可能与增强宿主的免疫功能相关。  相似文献   

变质量质系的拉格朗日方程     

李晓源  唐晓弟 《中南林业科技大学学报(自然科学版)》1996,(3)

推导了元质点结合与分离同时进行时，变质量质系的第二类拉格朗日方程表达式．  相似文献