Household Determinants of the Adoption of Improved Cassava Varieties using DNA Fingerprinting to Identify Varieties in Farmer Fields: A Case Study in Colombia

We examine factors affecting the adoption of improved cassava varieties of 217 households in the Cauca Department in southwest Colombia. Using DNA fingerprinting through Single Nucleotide Polymorphisms (SNPs), we identified different cultivars in farmers fields. We also used this information to remove possible bias in the adoption model that could have resulted from a misclassification of improved varieties (IVs). As a result, we found that farmers substantially overestimate their use of IVs and there are important differences in the determinants of adoption between farmer self‐identification and DNA fingerprinting. This finding implies that the incorporation of DNA fingerprinting in IV adoption studies is important to ensure the accuracy of future agricultural economic research and the relevance of subsequent policy recommendations.     

油葵SSR反应体系的优化

采用改良CTAB法从油葵种仁中提取基因组DNA,用于SSR-PCR反应。对影响油葵SSR-PCR反应的几个重要因子进行了探讨,确定了最佳的反应体系:在总体积为25μL中,DNA为2.0 ng/μL,Mg2+浓度为1.5 mmol/L,dNTPs浓度为0.2 mmol/L,Taq酶量为2.0 U,引物浓度为0.25μmol/L,退火温度为52～54℃,扩增的谱带清晰、多态性丰富。该SSR-PCR反应体系为油葵亲缘关系分析奠定了技术基础。     

企业兼并重组的文化机制研究

企业重组过程有着复杂的动机,但其过程表现为混沌动力学过程,其实质则是文化重组或文化基因的重新构造和复制。由此提出企业重组的文化机制建设问题,包括战略性的文化DNA识别机制、测试机制、复制机制、维护机制和整合机制,以及起辅助作用的容错机制和反馈机制,从而形成动态的文化整合机制。     

企业DNA模型结构新探

在对已有的企业DNA理论的研究成果总结的基础上,进一步分析企业DNA遗传物质的构成条件进而提出新的企业DNA模型,即企业DNA的双链为"经营"和"管理",遗传物质的四个碱基对分别为"经营理念"、"运行机制"、"核心技术"、"创业精神",并对遗传物质之间的互补性进行分析.     

基于模糊理论的产品设计DNA分析法研究

从生物学的DNA概念中得到启示,构建了“设计DNA分析法”的研究框架。基于设计形态学和产品语义学的相关理论和方法以及对现有设计DNA理论成果的研究,引出了设计DNA分析法的概念和分析法的六元分子。运用模糊识别法对分子中的元素进行识别,并基于模糊数学理论,采用模糊综合评判法,对所识别的结果进行验证。     

A Case of Mistaken Identity? Measuring Rates of Improved Seed Adoption in Tanzania Using DNA Fingerprinting

Studies of improved seed adoption in developing countries are almost always based on household surveys and are premised on the assumption that farmers can accurately self-report their use of improved seed varieties. However, recent studies suggest that farmers’ reports of seed varieties planted, or even whether the seed is local or improved, are sometimes inconsistent with the DNA fingerprinting results of those crops. We use household survey data from Tanzania to test the alignment between farmer-reported and DNA-identified maize seed types planted. In the sample, 70% of maize seed observations are correctly reported as local or improved, while 16% are type I errors (falsely reported as improved) and 14% are type II errors (falsely reported as local). Type I errors are more likely to have been sourced from other farmers, rather than formal channels. An analysis of input use, including seed, fertiliser, and labour allocations, reveals that farmers tend to treat improved maize differently, depending on whether they correctly perceive it as improved. This suggests that errors in farmers’ seed type awareness may translate into suboptimal management practices. The average yield of seed that is correctly identified as improved is almost 700 kg per hectare greater than that of type I errors. This indicates that investments in farmers’ access to information, seed labelling, and seed system oversight are needed to complement investments in seed variety development.     

我国生物制药现状分析

随着生命科学技术的飞速发展,生物技术在制药产业中的应用,生物制药产业有着极为光明的发展前景,是公认的朝阳行业.世界各国都纷纷将生物制药产业列为其重点发展的支柱性产业,投入了大量的人力物力和财力,力图占领这一科技制高点.本文详细描述了我国生物制药的蚬状,分析其存在问题,并探讨了生物制药的对策.     

食品检测中生物技术的有效运用

在食品科学技术发展与对外贸易不断扩大的背景下,食品检测与分析工作在保证食品安全中的地位越来越高。面对日渐严苛的食品检测要求,以生物技术取代传统分析方法是一种趋势,比如DNA探针技术、PCR技术和免疫学技术等。     

联遗传数字与DNA的数字模型

本文提出了三联遗传数字,三联变异数字,联遗传数字,联变异数字及互三联遗传数字等数学新概念。并对n个三联遗传数字链,n个三联遗传数字链的2种逐级收敛及逐级收敛的路径等作了重要的论述。旨在构建DNA与RNA的数字模型。     

Interpreting DNA Evidence: A Review

The paper provides a review of current issues relating to the use of DNA profiling in forensic science. A short historical section gives the main statistical milestones that occurred during a rapid development of DNA technology and operational uses. Greater detail is then provided for interpretation issues involving STR DNA profiles, including:

• – methods that take account of population substructure in DNA calculations;

• – parallel work carried out by the US National Research Council;

• – the move away from multiple independence testing in favour of experiments that demonstrate the robustness of casework procedures;

• – the questionable practice of source attribution 'with reasonable scientific certainty';

• – the effect on the interpretation of profiles obtained under increasingly sensitive techniques, the LCN technique in particular;

• – the use of DNA profiles as an intelligence tool;

• – the interpretation of DNA mixtures.

Experience of presenting DNA evidence within UK courts is also discussed. The paper then summarises a generic interpretation framework based on the concept of likelihood ratio within a hierarchy of propositions. Finally the use of Bayesian networks to interpret DNA evidence is reviewed.