A High Polymorphism Level in Rhinopithecus roxellana

The Sichuan golden monkey (Rhinopithecus roxellana) is a famous and beautiful endangered primate. Owing to the dearth of samples and technical limitations, previous studies could not adequately assess the levels of genetic polymorphisms in the species. To

Matrilineal Components and Genetic Relationship of Silkies from China and Japan

Silkie is a famous black-bone chicken breed with beautiful silky feather. The unique medical property of this chicken was recorded in Chinese traditional medicine dictionary about 700 years ago. In this study, we analyzed the mtDNA D-loop sequence variation of 26 Bairong Silkies from Fujian Province, China, together with 100 reported Silkie mtDNAs from China and Japan, and studied their matrilineal components and genetic relationship. A total of 21 haplotypes were detected, which could be assigned to six haplogroups (A-E, G). Among them, haplogroups D and G were exclusively presented in Japanese Silkies and Chinese Silkies, respectively. Chinese Silkies had higher frequency of lineages belonging to haplogroups A, B, and E, and lower frequency of haplogroup C than Japanese Silkies. For the four Chinese Silkie populations, most of samples of Taihe, Chengdu, and Hubei Silkies were grouped in haplogroups A, B, and C, whereas most of Bairong Silkies were grouped in haplogroup E. Five haplotypes were shared by Japanese and Chinese Silkies. The genetic diversity of each Silkie population varied, but the overall diversity of Chinese Silkies was similar to that of Japanese Silkies. Taken together, our results confirmed the genetic connection between Chinese and Japanese Silkies, but also clearly showed that the matrilineal genetic structures of Chinese and Japanese Silkies had some differences.

景观农业研究的兴起及其实际意义

Landscape agriculture is the combination of landscape ecology and agriculture. Its basic idea is from the system theory and landscape ecology. Now landscape agriculture is getting more and more attention because of its multi-functional roles. For example, it can exploit the agricultural ecosystem more rationally, make full use of the self-adjustment function of the natural patches and corridors in the field, as well as the effects from landform types and topological components. It uses regenerative biological energy to a large extent, constitutes beautiful scenic view and protects the diversity of genetics, species, ecosystems and landscapes. Landscape agriculture emphasizes environment improvement, bio-diversity protection and tourism development, thus provides new possibility for the increase of economical benefits and gets the positive feedback loop started. An example from the former Soviet Union is presented as well in this paper

中国水土流失的基本概况及其综合治理

水土流失是一个全球性的环境问题 ,给人类的生命和物质财产造成极大的危害与破坏。在现代社会 ,由于人口的持续增长、社会经济生产规模的不断扩大、植被破坏的急剧发展 ,对国家经济的发展构成了威胁。在上述背景下 ,本文在对以往研究结果进行综合分析的基础上 ,根据“再造一个山川秀美的西北地区”之要求 ,因地制宜地提出了我国水土流失的防治途径。

延安地区农业面临的问题与增产技术研究

:1 999年 8月朱总理为了落实江总书记“再造一个山川秀美的西北地区”和“把黄河的事情办好”的重要指示 ,视察黄土高原地区农业建设 ,从根治黄土高原的大局出发 ,强调采取“退耕还林 (草 ) ,封山绿化 ,个体承包 ,以粮代赈”的措施 ,动员广大人民群众 ,大搞植树种草 ,改善生态环境 ,为根治黄河奠基。面对总理的指示精神 ,退耕还林还草之后的农业如何发展 ?在人均 0 .0 7～ 0 .1 3hm2基本农田结构如何调整 ?农林牧关系如何协调 ?带着这些问题 ,我们通过在延安 70个农户中进行调查 ,指出了农业发展中存在的主要问题和面临的挑战 ,总结出效果明显的农业技术 ,供决策部门参考

黄土高原丘陵沟壑区的土壤侵蚀与土地利用

黄土高原丘陵沟壑区生态农业建设的目标是调和自然和人类的关系 ,不合理的土地利用是导致土壤侵蚀的主要因素 ,控制严重的土壤侵蚀并改善提高当地人民的生活水平 ,合理利用土地资源调整土地利用结构是建设秀美山川的根本出路

Low-density polyethylene superhydrophobic surface by control of its crystallization behavior

A simple and inexpensive method for forming a low-density polyethylene (LDPE) superhydrophobic surface by controlling the crystallization behavior of LDPE by adjusting the crystallization time and nucleation rate has been proposed. The resulting porous surface, with hierarchical micro- and nanostructures on the beautiful floral designs, has a water contact angle of 173.0degrees +/- 2.5degrees.

改进型地雷引信压发测试台

针对原地雷引信压发测试台存在的问题,提出改进方法和措施;详细介绍了改进后测试台的系统构成以及工作原理。改进前后的对比结果表明,改进型测试台实现了漏检率为0,无链条卡死现象,能够适用4种引信,且外表美观。