Age and growth of Schizothorax waltoni in the Yarlung Tsangpo River in Tibet, China

Age and growth were studied for Schizothorax waltoni in the middle reaches of the Yarlung Tsangpo River in Tibet, southwest of China, from April 2004 to September 2006. A total of 201 specimens were collected ranging from 110 to 580 mm in standard length (SL). In contrast to other otoliths, sectioned lapillus showed a clear pattern of alternating opaque and hyaline zones. Marginal increment analyses showed that the increments, each composed of one opaque and one hyaline zone, are deposited annually. Opaque edges were prevalent from May to August. The von Bertalanffy growth parameters based on sectioned otolith data were L (t) = 689.8{1 - exp[0.051 (t + 3.275)]} for males, and L (t) = 691.1{1 - exp[0.056 (t + 2.466)]} for females. The slow growth and long life indicate that S. waltoni is vulnerable to overfishing and that harvesting strategies for the species should be conservative.

Tandem organic light-emitting diodes with an effective charge-generation connection structure

The tandem organic light-emitting diodes (OLEDs) with an effective charge-generation connection structure of Mg-doped tris(8-hydroxyquinoline) aluminum (Alq(3))/Molybdenum oxide (MoO3)-doped 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) were presented. At a current density of 50 mA/cm(2), the current efficiency of the tandem OLED with two standard NPB/Alq(3) emitting units is 4.2 cd/A, which is 1.7 times greater than that of the single EL device. The tandem OLED with the similar connection structure of Mg-doped PTCDA/MoO3-doped PTCDA was also fabricated and the influences of the different connection units on the current efficiency of the tandem OLED were discussed as well.

次生林经营基础研究进展

次生林是中国森林的主体 ,在结构组成、林木生长、生产力、林分环境等诸多方面与原始林和人工林有着显著的不同 .因此 ,经营好次生林对中国天然林保护等林业工程实施及国家生态安全建设具有重大意义 .本文在广泛收集国内外有关次生林研究结果的基础上 ,探讨了次生林经营领域中基础研究所涉内容 ,揭示出次生林经营研究中所关注的基础问题 ,提出了次生林经营基础研究的主要内容与方向 ,对今后次生林经营研究和中国天然林保护等林业工程建设具有参考价值 .

发展林业碳汇推动三北防护林体系建设

三北防护林体系建设作为中国六大林业重点工程之一,30年来取得了巨大成就。但长期以来,工程建设资金不足一直困扰着工程发展。林业碳汇的兴起和快速发展,将对其产生重大影响。本文在对林业碳汇进行分析的基础上,提出了加快发展林业碳汇推动三北防护林体系建设的建议。