SURVEY OF MIXED INFECTIONS OF FISH-BORNE TREMATODES IN PINYUAN COUNTY AND DNA(RAPD)ANALYSIS

目的　调查广东省平远县棘隙吸虫及其他鱼源性吸虫混合感染情况。方法　对鱼类宿主取鱼鳃和鱼肉等组织 ,镜检囊蚴 ;用水洗过筛沉淀法粪检虫卵 ,部分虫卵阳性动物解剖检查。采用DNA -RAPD技术 ,比较福建棘隙吸虫广东株与福建株。结果　查出华支睾吸虫 (Clonorchissinensis)、东方次睾吸虫 (Metorchisorientalis)、福建棘隙吸虫 (Echinochasmusfujianensis)、日本棘隙吸虫 (E japonicus)、抱茎棘隙吸虫 (E perfoliatus)和钩棘单睾吸虫 (Haplorchispumilio) 6种。第二中间宿主为麦穗鱼等 11种 ,感染率 48 3% (182 / 377) ,有 92 4%的阳性鱼混合感染 2种以上吸虫囊蚴。保虫宿主狗、猫感染率 79 2 % (19/ 2 4) ,每只阳性动物均有 2种以上吸虫混合感染。 15个引物在福建棘隙吸虫广东株与福建株两者共获DNA片段 185个 ,共享度 (F) =0 984,遗传距离 (D) =0 0 16。结论　当地为人兽共患的多种鱼源性吸虫混合感染区。形态学观察和分子生物学检测结果相印证 ,福建棘隙吸虫广东株与福建棘隙吸虫福建株为同一虫种。Aim To seek the possible existence of mixed infections of Echinochasmus fujianensis and other fish-borne tremtodes in Pinyuan county,Guangdong.Methods Metacercariae of trematodes were detected from gills,muscles and some other tissues of freshwater fish and examintd under microscopy Sedimentation pocedures were used to observe parasite ova in stool Adult worms were obtained from definitive animal hosts upon dissection Experimental animal infection were performed from metacercariae of E fujianensis strains in Fujian and Guangdong,and it's DNA analysis Random amplified Polymorphic DNA(RAPD).Results Six species of trematodes were found,including Clonorchis sinensis,Metorchis orientalis,E fujanensis, E japonicus,E perfoliatus and Haplorchis pumilio Eleven species of freshwater fish comprising Pseudorasbora parve were identified as the second intermediate hosts,with an average positive rate of 48 33%(182/377) The overall mixed infection animal were contracted with 2 or more species Dogs and cats were detected to be reservoir hosts,the total infection rate being 79 2%(19/24).92 4% of infecded fish were contracted with 2 or 6 speies of the metacercariae of trematodes 185 DNA fragments were obtained by 15 primers,F=0 894 and D=0 016 between E fujianensis Guandong and Fujian strain Conclusion There are six species of fish-borne trematodes which may cause infections in human and animal in the regions E fujianensis Guangdong stain and Fujian strain are the same species福建省科技计划基金!资助项目 (No 98-Z - 1 56);; 福建省“百千万人才”人选培养资

Managerial Ownership and Corporate Performance ： The Model Explanatory Power Endogeneity and the Industry Competition ，

本文以２００１ ～ ２００５ 年深沪两市上市公司为研究样本， 以委托代理理论、团队生产理论等为基础， 通过构建混合横截面数据分析管理层持股与公司业绩之间的非线性关系， 验证“利益趋同假说” 和“防御假说” ， 并对线性模型和非线性模型的解释力进行比较。在此基础上， 本文讨论管理层持股与公司业绩之间的内生性， 探讨在我国目前特殊的制度背景下到底管理层持股决定公司业绩， 还是公司业绩决定管理层持股， 抑或是管理层持股和公司业绩两者相互决定， 并对管理层持股和企业业绩之间的内生性采取三阶段回归模型（３SLS） 进行处理， 再次审视剔除内生性之后两者之间的相关性。最后， 本文 还分析不同行业的竞争程度对管理层持股与公司业绩之间关系的影响。本文的研究发现： ① 管理层持股与公司业绩之间呈二次非线性关系， 但线性模型和非线性模型在目前我国管理层持股总体水平偏低的情况下， 具有相似的解释和预测能力。② 通过建立单一方程和联立方程来分析两者的相互影响性， 发现管理层持股与公司业绩之间具有内生性。③ 行业竞争程度与管理层持股激励效果相关， 公司所处的行业竞争程度越高， 管理层持股的激励效果更好； 而越是垄断性的行业， 管理层持股的激励效果越差。The paper investigates the companies listed in Shenghai and Shenzhen securities exchanges over the ２００１ ～ ２００５ period Using mixed cross sectional data ， we analyze the nonlinear relation between managerial ownership and corporate performance and examine the the convergence of interest hypothesis and the entrenchment hypothesis We also compare the explanatory power between linear and nonlinear models Furthermore ， the paper discusses the causes and consequences between managerial ownership and corporate performance to decide whether managerial ownership dominate corporate performance or corporate performance dominate managerial ownership or managerial ownership and corporate performance interactive underlying Chinese capital markets ， and the paper adopts ３ SLS to deal with endogenous relation between managerial ownership and corporate performance Our results show that ： firstly ， there is a twosquare nonlinear relation between managerial ownership and corporate performance ， but the explanatory power between linear and nonlinear model is similar Secondly ， the paper adopts single and Simultaneous Equation to analysis cause and consequences and finds that managerial ownership and corporate performance have endogenous relation ． Final ly ， industry competition characteristic affects the incentive effects of managerial ownership ， and more competitive industry have better incentive effects ， monopoly industry have worse or little incentive effects作者单位：厦门大学会计系＼ 厦门大学会计发展研究中心,光大证券股份有限公

中国贝母属(Fritillaria)7种植物的核型研究（英文）

通过对7种国产贝母属(Fritillaria)植物的染色体核型进行观察和研究,报道了小白花贝母(F. albidoflora Duan&Zheng)、川贝母(F. cirrhosa Don)、伊贝母(F. pallidiflora Schrenk ex Fischer&Meyer)、华西贝母(F. sichuanica Chen)、托里贝母(F. tortifolia Duan&Zheng)、新疆贝母(F. walujewii Regel)、裕民贝母(F. yuminensis Duan)等7种植物的染色体数目及核型,其中3种为首次报道。结果显示,7种国产贝母属植物的核型均具有高度不对称性。此外,小白花贝母与已报道的黄花贝母(F. verticillata Willdenow)的核型存在明显差异,提示Flora of China将小白花贝母归并入黄花贝母的分类处理可能并不恰当,二者的关系需进一步研究

神舟飞船生长GaMnSb材料过程及性能分析

利用神舟3号飞船(SZ-3)上的多样品空间晶体炉制备出GaMnSb材料.所设计的石英安瓿使用氧化铝棉毡和特殊设计制造的氮化硼坩锅进行减震,经受住了严峻的力学环境的考验,完成了材料的空间生长实验,达到了空间生长材料的初步要求.对空间生长的GaMnSb 晶体进行了X射线能谱分析和X射线衍射分析,发现空间生长的GaMnSb是多晶结构.对未获得GaMnSb单晶的原因进行了分析,发现空间晶体炉温度的波动和提供能量的不足是导致生成GaMnSb多晶结构的主要原因.由于在晶体生长的初始阶段晶体炉提供的能量不足,使GaSb单晶部分未能熔化,从而导致GaMnSb材料的生长在没有籽晶的情况下进行

取向构元组集模型的弹性损伤理论

"对泛函势"是多种材料势能的很好近似.在计算材料势能过程中,分别由对势和嵌入势抽象出取向构元和体积构元,这两种构元的能量和就是材料的势能.材料损伤的本质是原子键合力的破坏,由于取向构元是原子间键的抽象,反映在构元层次上,损伤是构元刚度的减小.组集所有构元的响应函数,得到了材料的弹脆性损伤本构关系,这种基于构元组集的材料本构被称为"取向构元组集"材料模型.理论分析和数值实验表明,本模型具有概念清晰,物理直观,以及表示各向异性自然等特点

古尔班通古特沙漠半固定沙垄表面风速变化规律研究

于2007年春季(风季),利用DETI可移动测风系统对古尔班通古特沙漠半固定沙垄进行实地观测,系统研究沙垄表面2m高度气流速度变化规律,发现坡脚风速、入射角和坡面形态对其有显著影响。在大气呈中性稳定的条件下,风速由迎风坡脚至丘顶逐渐加速,在垄顶达到最大,至背风坡的中上部剧烈降低,此后又逐渐恢复。垄顶风速随坡脚风速的增大而线性增大。在相同风速条件下,大角度入射时迎风坡的风速增加幅度和背风坡的风速降低幅度均明显高于小角度入射的情形,可见入射角的大小控制着沙垄表面风速的变化幅度。地形对风速变化的影响在于,在缓而长的坡面上,迎风坡风速放大率较短而陡的坡面要大,当短而陡的坡面作为背风坡时,风速的降低则较缓长的坡面更为剧烈。对古尔班通古特沙漠半固定沙垄表面风流速度变化规律进行研究,将有助于理解半固定沙垄表面的蚀积过程和动态,为科学防沙治沙提供理论依据

春夏季放牧对古尔班通古特沙漠南部土壤种子库和地上植被的影响

位于新疆北部准噶尔盆地腹地的古尔班通古特沙漠,是世界上温带荒漠生物多样性的精华和最为丰富的典型区域。历史上这里就是北疆羊和部分马匹重要的冬牧场,但近年来的放牧活动在春夏季也开始进入沙漠腹地,使地表性质与植被覆盖发生了明显改变。应用野外随机取样与室内萌发实验相结合的方法,对比研究了古尔班通古特沙漠南部春夏季放牧和冬季放牧沙垄土壤种子库差异及其与地上植被的关系。结果表明:冬季放牧沙垄种子库种数为24种,而春夏季放牧沙垄有20种,后者明显减少了植物种数。冬季放牧沙垄种子库密度为(353.2±87)粒.m-2,而春夏季放牧沙垄为(189.1±23)粒.m-2,比前者减少了88%。两类沙垄土壤种子库的生活型组成都以一年生植物为主,相似性系数为0.711。相同沙垄不同部位的物种相似性系数在0.429~0.600之间,异质性较大,尤其表现在除垄顶之外的其他部位。冬季放牧沙垄和春夏季放牧沙垄地上植被中分别有植物36种和26种,各生活型所有物种均为后者低于前者,其中短命、类短命物种数量减少幅度最大。春夏季放牧沙垄地上植被的物种多样性和均匀度降低,而优势度升高。回归分析显示,冬季放牧沙垄定植群落有21%的变异来源于土壤种子库,而春夏季放牧沙垄有51%的变异来源于土壤种子库,可见不同季节的放牧干扰显著影响土壤种子库及其与地上植被的相关关系

用PIXE方法分析三苯基磷羰基铑催化剂中磷和铑的百分含量

本文叙述了分别以钴和钇做内标,用PIXE方法分析三苯基磷羰基铑催化剂中的磷和铑。结果表明:磷和铑在催化剂中的百分含量分别为1.951％和0.113％,与理论估算值非常接近

Study of the damage-induced anisotropy of quasi-brittle materials using the component assembling model

Damage-induced anisotropy of quasi-brittle materials is investigated using component assembling model in this study. Damage-induced anisotropy is one significant character of quasi-brittle materials coupled with nonlinearity and strain softening. Formulation of such complicated phenomena is a difficult problem till now. The present model is based on the component assembling concept, where constitutive equations of materials are formed by means of assembling two kinds of components' response functions. These two kinds of components, orientational and volumetric ones, are abstracted based on pair-functional potentials and the Cauchy - Born rule. Moreover, macroscopic damage of quasi-brittle materials can be reflected by stiffness changing of orientational components, which represent grouped atomic bonds along discrete directions. Simultaneously, anisotropic characters are captured by the naturally directional property of the orientational component. Initial damage surface in the axial-shear stress space is calculated and analyzed. Furthermore, the anisotropic quasi-brittle damage behaviors of concrete under uniaxial, proportional, and nonproportional combined loading are analyzed to elucidate the utility and limitations of the present damage model. The numerical results show good agreement with the experimental data and predicted results of the classical anisotropic damage models