县·乡镇两级尺度下耕地质量空间自相关分析——以湖北省广水市为例

[目的]从县级、乡镇级两级空间尺度上运用空间自相关分析(Moran’s I)方法定量研究广水市耕地质量的空间集聚性规律特征。[方法]基于空间自相关Moran’s I分析方法,以湖北省广水市为研究区,将耕地质量国家自然等指数、利用等指数和经济等指数作为空间变量,以耕地图斑作为空间单元进行空间自相关分析,从县级和乡镇级两级尺度上分析耕地质量空间差异性特征并进行两级对比分析。[结果]广水市耕地质量在空间分布上呈现出一定的集聚性规律,"中北部"的耕地质量较高,"西北角"耕地质量相对较低,其他地方耕地质量处于中等水平且分布较集中。广水市耕地质量在县级和乡镇级尺度上呈现出较强的空间自相关,说明在空间格局上呈现出很强的集聚态势。县、乡镇两级尺度上,耕地质量指数Moran’s I值均呈现出国家经济等指数国家利用等指数国家自然等指数的递减特征,三者均呈现显著的空间正相关集聚态势。[结论]耕地质量空间差异在不同尺度上有一定的敏感性和内部差异性特征,耕地质量空间差异特征研究可为土地整治、高标准基本农田划定等工作提供参考。     

微波辅助提取酸浆籽中多糖方法优化

采用微波辅助提取技术,研究微波功率、处理时间及料液比对脱脂酸浆籽中多糖提取率的影响。运用minitab15.0数据分析软件,采用Box-Behnken的中心组合设计,采用三因素三水平的响应面法优化工艺条件,建立微波提取多糖的二次多项数学模型,并以多糖的提取率为响应值做响应面,得到优化条件为:料液比1∶12,微波功率610 W,微波处理时间83 s。在此条件下实际多糖提取率为5.57%。     

秦岭羚牛的保护生物学研究进展

秦岭羚牛（Budorcas taxicolor bedfordi）作为"秦岭四宝"之一，是国家一级重点保护动物，被世界自然保护联盟（International Union for Conservation of Nature,IUCN）列为易危级物种。本文从秦岭羚牛的生态学、分类学地位、寄生虫病、瘤胃微生物区系、功能基因挖掘及人工圈养等方面总结已有的研究成果，并对其研究进展进行综述，指出目前研究存在的不足，提出今后的研究方向，以期为秦岭羚牛的保护和管理提供  参考。     

黄土高原梯田质量评价系统设计研究

针对黄土高原的自然环境条件,提出了梯田质量评价的指标体系、评价系统的设计原则及方法。探讨了梯田质量评价系统的主要模块,研究了梯田数据库的结构及主要内容,利用VisualBasic6．0与MapX5．0相结合,开发了黄土高原梯田质量评价信患系统,实现了属性信息与空间信患的相互查询、统计分析以及对梯田质量进行评价。本系统的建立能够对梯田建设与管理提供科学依据,为黄土高原水土保持工作提供基础资料,具有一定的社会和经济效益。     

在预应力混凝土桥梁中高强混凝土的使用

本文介绍了高强混凝土(HSC)的开发过程。高强混凝土的特性:如抗压强度很高时,抗弯折及抗拉则不再有增加的趋势;弹性模量与抗压强度不成反比:HSC的应力～应弯曲线与普通混凝土不同等。高强混凝土优点:若配置相同量的抗拉钢筋,则可提高构件的抗变形性能等。并谈了施工注意的事项。     

毛白杨树皮内含物对光肩星天牛抗性的探讨

毛白杨树皮内含物对光肩星天牛抗性的探讨王蕤，巨关升，秦锡祥（中国林业科学研究院林业研究所北京１０００９１）关键词杨树，抗性，酚酸，酚甙光启星天牛（ＡｎｏｐｌｏｐｈｏｒａｓｌａｂｒｉｐｅｎｎｉｓＭｏｔｓｈ．）对杨树危害严重，受害的树种多，涉及的地域广，...     

Ergot alkaloid transport across ruminant gastric tissues

Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected tall fescue. It is generally accepted that ergovaline is the toxic component of endophyte-infected tall fescue, but there is no direct evidence to support this hypothesis. The objective of this study was to examine relative and potential transport of ergoline and ergopeptine alkaloids across isolated gastric tissues in vitro. Sheep ruminal and omasal tissues were surgically removed and placed in parabiotic chambers. Equimolar concentrations of lysergic acid, lysergol, ergonovine, ergotamine, and ergocryptine were added to a Kreb's Ringer phosphate (KRP) solution on the mucosal side of the tissue. Tissue was incubated in near-physiological conditions for 240 min. Samples were taken from KRP on the serosal side of the chambers at times 0, 30, 60, 120, 180, and 240 min and analyzed for ergot alkaloids by competitive ELISA. The serosal KRP remaining after incubation was freeze-dried and the alkaloid species quantified by HPLC. The area of ruminal and omasal tissues was measured and the potential transportable alkaloids calculated by multiplying the moles of transported alkaloids per square centimeter of each tissue type by the surface area of the tissue. Studies were conducted to compare alkaloid transport in reticular, ruminal, and omasal tissues and to determine whether transport was active or passive. Ruminal tissue had greater ergot alkaloid transport potential than omasal tissue (85 vs 60 mmol) because of a larger surface area. The ruminal posterior dorsal sac had the greatest potential for alkaloid transport, but the other ruminal tissues were not different from one another. Alkaloid transport was less among reticular tissues than among ruminal tissues. Transport of alkaloids seemed to be an active process. The alkaloids with greatest transport potential were lysergic acid and lysergol. Ergopeptine alkaloids tended to pass across omasal tissues in greater quantities than across ruminal tissues, but their transport was minimal compared to lysergic acid and lysergol.     

畜产品安全中存在的问题与分析

阐述了我国畜产品安全现状，强调了其形势的严峻性和紧迫性，分析了当前存在的主要问题，并提出了改进措施和建议。