少数民族地区现代特色农业发展的新路径——以广西恭城红岩村为例

分析了少数民族地区发展特色农业的优势,如具有国家政策的扶持、自然资源丰富、当地具有特色民族文化等。以广西恭城红岩村为例,介绍了当地特色农业——月柿产业发展现状,提出了少数民族地区发展现代特色农业的新路径:实施品牌化战略,推动特色农业全产业链发展;促进特色农业与少数民族文化融合发展;深化特色农业与休闲生态旅游的结合。     

链锯切削参数微机检测的研究

介绍用TP 801单板计算机配以适当的传感系统、放大电路、A/D转换电路、接口电路等安装在链锯实验台上,每次实验可自动打印出链锯切削参数。此方法即经济又方便准确,打破了常规的检测方法,为链锯参数测定开辟了一条新途径。本文阐述了切削参数的数学模型、检测原理、程序框图及有关实验数据。为研究链锯性能、选型,研制适合我国国情的利于林业生产的油锯提供了理论依据。     

马尔可夫链及其在林业预测中的应用

马尔可夫链是一种随机模型。它可以用来预测、分析具有多种状态的随机系统。本文介绍了马尔可夫链的基本概念和方法,并就在林业预测中的两个问题——林木病害预测和森林资源变化预测进行了讨论和分析。     

Geographical traceability of an important tropical timber (Neobalanocarpus heimii) inferred from chloroplast DNA

The inbuilt unique properties of DNA within the timber could serve as tracking and monitoring tools to verify the legality of a suspected timber in the context of illegal logging, forest certification and chain of custody certification. By using Neobalanocarpus heimii (Dipterocarpaceae) as an example, a population identification database and haplotype distribution map in Peninsular Malaysia were generated for authenticity testing based on four chloroplast DNA markers (trnL intron, trnG intron, trnK intron and psbK-trnS spacer). Twenty one haplotypes were identified from 10 significant intraspecific variable sites. The results clearly revealed that only northern and southern regions of Peninsular Malaysia were distinguishable. Thus, this database could only be used to determine the wood lot of unknown origin at the regional level. Statistical procedure based on the composition of wood lot was used to test whether a suspected timber conforms to a given regional origin. Overall, the observed type I and II errors of the database showed good concordance with the predicted 5% threshold, which might indicate that the database is useful to reveal provenance and establish conformity of wood lot from northern and southern regions of Peninsular Malaysia. Applications of this database for timber tracking are discussed.     

基于哈希密钥链的无线传感器网络密钥预分配方案

目前,主要通过研究密钥管理来保证无线传感器网络的安全。在基于密钥预分配的方案中,当前研究的热点是随机密钥预分配模型,但它面临一个潜在的挑战,即无法同时获取理想的网络安全连通性和网络抗毁性。为此,提出一种基于哈希密钥链的随机预分配方案,利用密码学的哈希函数提高方案的抗节点俘获能力,增强网络的安全性,且在与E-G方案同等网络连通概率下具有较小的存储消耗和通信消耗。     

未来县域城乡用地变化趋势研究——以安义县为例

以南昌市安义县近10 a来土地利用现状调查数据为基础,运用灰色-马尔可夫链的基本原理,分析了该县城乡用地的需求量,预测了该县未来15 a城乡用地逐年的规模量,并运用信息熵等研究了该县未来城乡用地的结构变化趋势.     

ＮＲ链传动运行平稳性试验分析

对自行研制的具有遥则功能的ＮＲ链条和链传动态特性试验台进行了分析,在ＮＲ链传动与普通链运动动态特性对比试验中引入了现代谱分析方法,给出了衡量运动平衡性的定量值和噪声值,试验结果与理论分析基本一致,验证了所提理论的正确性。     

Heritability of quantitative traits in segregating common bean families using a Bayesian approach

Genetic parameters for six quantitative traits in the early generation of segregating populations of common beans (Phaseolus vulgaris L.) were evaluated. A Bayesian approach was used for estimating the variance components, breeding values and broad sense heritability of the quantitative traits under analysis. The Markov Chain Monte Carlo method was utilized to analyze the contribution of genes affecting complex traits. Twenty-four F₃ families were evaluated in the field during 2005 in Santa Catarina, southern Brazil. With regard to the grain yield and yield components, the additive variances were relatively similar to the dominance variances. This result is confirmed by the 95% credible set from the posterior distribution. The mean estimates of broad-sense heritability (H²) varied from 11.5% to 64.2%. The heritability estimates of yield and yield components were higher than the estimates for the number of days until flowering and reproductive period. However, for grain yield, the 95% heritability credible set included the heritability estimates from point of crop duration. The predicted genetic gain reached the highest value for the number of pods per plant (10.95%). Days to flowering and reproductive period had the lowest values of genetic advance. One hundred seed-weight, grain yield and seeds per pod exhibited a similar predictable level of genetic gain: GA = 5.73%, 5.81% and 4.77%, respectively. The Bayesian framework provided information that is useful for a breeding program, since it contributes to the understanding of how quantitative traits are genetically controlled.     

PCR-RFLP方法在蛔虫种间鉴别上的应用

研究应用PCR－RFLP方法初步鉴别了4种不同蛔虫。从猪蛔虫、人蛔虫、犬弓首蛔虫及鸡蛔虫中分别提取基因组DNA，通过PCR扩增得到长度分别约为450bp、450bp、530bp、550bp的PCR产物。经与国外报道相比较，确认完整扩增出4种蛔虫的第二内部转录间隔区（ITS－2）片段。PCR产物经限制性内切酶HaeⅢ和Hinf I酶切鉴定，通过产生的特异性片段首先可以区分犬弓首蛔虫与鸡蛔虫。通过对4种蛔虫的基因组DNA进行扩增，得到长度分别约为980bp、980bp、1050bp、1070bp的PCR产物。经与国外报道相比较，确认完整扩增出4种蛔虫的ITS－1、ITS－2及5.8S核糖休DNA。PCR产物经限制性内切酶HaeⅢ酶切鉴定，通过产生的特异性片段可以区分出猪蛔虫与人蛔虫。通过PCR－RFLP分析，初步推测猪蛔虫与人蛔虫仍为两个独立虫种，但尚需进一步研究确认。     

马尔柯夫过程预测焉耆盆地土地利用/覆被格局变化

在遥感和MAPGIS的支持下,由焉耆盆地两个时期的遥感图像和地形图获得的土地利用/覆被类型数据,确定土地利用/覆被的初始状态矩阵和转移概率矩阵,据此用马尔柯夫链模型对焉耆盆地的土地利用/覆被格局的未来变化趋势进行了预测。X2检验表明,模拟结果与实际情况基木吻合,因此用该模型预测未来土地利用/覆被格局的变化是可靠的。结果表明:天然植被、盐碱地持续减少,而耕地面积、水域、以及城市居民点继续扩大,说明焉耆盆地土地利用/覆被格局正处在一种变化状态,这预示着未来时期焉耆盆地绿洲区人为干扰仍然是土地利用/覆被格局变化的主要方面。根据模拟结果可调整各类土地利用/覆被格局,可为干旱绿洲区土地利用规划宏观决策提供科学依据。