类胡萝卜素吸收研究进展

关于类胡萝卜素的吸收机制说法不一,目前体外培养的细胞模型被广泛用于类胡萝卜素的吸收研究。本文主要从细胞水平上讨论了类胡萝卜素的吸收研究进展,并详细讨论了类胡萝卜素吸收机制方面研究较多的选择性吸收及吸收过程中的相互影响。细胞对β-胡萝卜素的摄入和分泌表现出浓度依赖性、时间依赖性和饱和性;对不同类胡萝卜素的吸收表现出选择性;类胡萝卜素在吸收过程中表现出相互影响。上述研究结果表明,类胡萝卜素的吸收可能是一个有载体参与的易化运输过程。     

Haplotype analysis of β-actin gene for its association with sperm quality and boar fertility

β‐actin (ACTB) was examined as a direct functional candidate gene for the possible association with sperm concentration, motility (MOT), semen volume per ejaculate, plasma droplet rate, abnormal sperm rate (ASR) and the fertility traits, non‐return rate and number of piglets born alive (NBA). Three polymorphisms in intron 3 (T>C) and one polymorphism in exon 4 (T>C) of porcine ACTB gene were identified by comparative sequencing of animals of the breeds Pietrain and Hampshire. Association analysis revealed that haplotypes affected the variation of the traits MOT, ASR and NBA. The beneficial haplotypes may provide considerable improvement of sperm quality and fertility in the tested commercial boar population.     

Diversity of methodologies to experiment Integrated Pest Management in arable cropping systems: Analysis and reflections based on a European network

Integrated Pest Management (IPM) aims to promote physical and biological regulation strategies that help farmers contain populations of pests (pathogens, animal pests and weeds) and to finally reduce the reliance on pesticides. It is based on the holistic combination of multiple management measures rather than on the sum of single methods, each of them having only small effects on pests reduction. Thus, to analyse the interactions between IPM measures and to evaluate the sustainability of their implementation, we require an approach considering the whole cropping system (CS), i.e. a functional entity whose complexity is more than the sum of its parts. A network of European experiments at the CS level was set up recently, and aimed at sharing data and expertise to enhance knowledge of IPM. Comparison of existing methodologies highlighted a diversity of CS designs and experimental layouts. We deduced that the concept of CS itself was viewed differently among scientists, and this affected experimental protocols. Other differences were related to the research context and objectives. Some experiments aimed to explore very innovative strategies and generated knowledge on both their effects on the agroecosystem and their ability to satisfy a set of performance targets, while others aimed to provide quickly adoptable solutions for local farmers in line with the current socio-economic constraints. In some research programmes, the experiment was part of the CS design process — and tested CS were regularly revised based on an continuous improvement loop — while in other cases CS were kept stable across years so as to enable the evaluation of their long-term cumulative effects. A critical aspect contributing to the diversity among CS experiments was the distinction between a factorial design of experimental CS and systemic approaches: factorial experiments allowed quantification of the effects of each IPM component regardless of the consistency between components defining the CS. In contrast, systemic approaches focused on the overall evaluation of CS designed with consideration of their consistency, hence maximising their ability to meet the objectives. Because CS experiments represent a huge investment in terms of economics and time, preliminary reflections of the relevance of the experimental strategy is of critical importance.     

所有权概念探讨

在对比各国对所有权的不同界定的基础上,立足于我国国情,重新阐释了所有权的概念。     

毛泽东系统整体优化方法探析

系统整体优化方法是一种科学方法。毛泽东在领导中国人民进行革命和建设的伟大征程中，十分注重将整体优化原则应用于思想方法和工作方法，并形成了相应的系统优化方法。深入探究毛泽东的系统优化方法，具有十分重要的科学价值和现实意义。     

反应网络的物料平衡一致性校验

通过对反应网络的物料平衡分析，提出了反应网络的物料平衡一致性校验方程，并用于反应网络的数据校正和推测     

农用地估价方法综述

农用地估价的常用方法有：收益还原法、收益倍数法、成本法、假设开发法、市场比较法、影子价格法、享乐定价法、土壤潜力估价法、标准田法等。这些估价方法对我国农用地的可操作性、适用范围．学术界有不同的看法，文章对这些观点进行了综述与分析。     

消除高职学生学习高等数学的心理障碍的途径

就高职院校高等数学课程教学改革作了一些探讨，针对高职院校的现状，分析了高职学生学习高等数学的心里障碍成因，并提出分层次教学、概念教学以及改变考核方式等途径的解决方法。     

神农架林区森林资源可持续发展途径探讨

笔者以神农架林区为例,用全面规划、总体布局的观点分析林区资源特点与利用现状问题,并以天然林保护工程为重点,实现森林保护多种效益的永续利用为目标,以探讨我省国有林区森林资源可持续发展的有效途径,提出国有林区森林资源可持续发展的关键是对现有林科学合理地经营和管护,并指出在禁伐区、一般公益林区和商品林区应采取的不同策略。