收入分配对农村居民恩格尔系数的影响研究

恩格尔系数是衡量居民生活水平的重要指标.本文通过理论分析和实证研究发现:收入差距扩大降低了我国农村居民的恩格尔系数,提高了农民总体生活水平,收入差距对总体生活水平上升的贡献度达到1/3,从而出现"分配越不平等,农民生活水平越高"的悖论.因此在对农民生活做(福利)评价时,必须同时考虑总体指标和分配指标,在发展农村经济、提高农民生活水平过程中,必须重视收入分配,兼顾公平与效率,才能实现农民的福利最大化.     

Birds movement impact on the transmission of West Nile virus between patches

Spatial heterogeneity plays an important role in the distribution and persistence of many infectious disease. In the paper, a multi-patch model for the spread of West Nile virus among $n$ discrete geographic regions is presented that incorporates a mobility process. In the mobility process, we assume that the birds can move among regions, but not the mosquitoes based on scale-space. We show that the movement of birds between patches is sufficient to maintain disease persistence in patches. We compute the basic reproduction number $R_{0}$. We prove that if $R_{0}<1$, then the disease-free equilibrium of the model is globally asymptotically stable. When $R_{0}>1$, we prove that there exists a unique endemic equilibrium, which is globally asymptotically stable on the biological domain. Finally, numerical simulations demonstrate that the disease becomes endemic in both patches when birds move back and forth between two regions.     

Enhanced migrating birds optimization algorithm for the permutation flow shop problem with sequence dependent setup times

This paper presents an enhanced migrating bird optimization (MBO) algorithm and a new heuristic for solving a scheduling problem. The proposed approaches are applied to a permutation flowshop with sequence dependent setup times and the objective of minimizing the makespan. In order to augment the MBOs intensification capacity, an original problem specific heuristic is introduced. An adapted neighborhood, a tabu list, a restart mechanism and an original process for selecting a new leader also improved the MBO’s behavior. Using benchmarks from the literature, the resulting enhanced MBO (EMBO) gives state-of-the-art results when compared with other algorithms reference. A statistical analysis of the numerical experiments confirms the relative efficiency and effectiveness of both EMBO and the new heuristic.     

刺参南移养殖技术研究

刺参南移南麂岛(272°7′N,1210°5′E)生长良好,发育正常。成参夏眠从6月上旬开始,11月中旬结束,历时约160d,水温28℃以上持续时间约30d;自繁稚参度夏期间摄食和活动正常,生长良好,成活率50%。分析了刺参在浙闽沿海养殖的可行性,提出利用闲置育苗设施和开发近岸低位坑道养殖刺参及刺参、鲍鱼混养的建议。     

蓝色犁头霉JY-2#的选育与发酵特性

将经过紫外线诱变的蓝色犁头霉原生质体倾注于含有化合物RSA（17α-羟基孕甾4-烯-3,20-二酮-21-醋酸酯）的高渗再生培养基平板上,选育具有RSA抗性的氢化可的松生产菌株。获得60株抗性突变株,其中8株突变株的氢化可的松转化率高于出发菌株。突变株JY-2^#的氢化可的松转化率达81．63％,较出发菌株提高了14．1％。初步研究了突变株JY-2^#在5L发酵罐的转化工艺和转化反应动力学。     

花鲈繁殖生物学及繁育技术研究进展

从花鲈的产卵类型、产卵期、繁殖力、卵和仔鱼发育等几个方面综述了花鲈繁殖生物学特性;提出了亲鱼选择、促熟培育,人工催产以及苗种培育的有关技术措施,并对人工育苗过程中存在的问题进行了探讨,为花鲈的大规模人工养殖提供参考.     

Advances in genomic selection in domestic animals

Genomic selection (GS) is a marker-assisted selection method, in which high density markers covering the whole genome are used simultaneously for individual genetic evaluation via genomic estimated breeding values (GEBVs). GS can increase the accuracy of selection, shorten the generation interval by selecting individuals at the early stage of life, and accelerate genetic progress. With the availability of high density whole genome SNP (single nucleotide polymorphism) chips for livestock, GS is reshaping the conventional animal breeding systems. In many countries, GS is becoming the major genetic evaluation method for bull selection in dairy cattle and GS may soon completely replace the traditional genetic evaluation system. In recent years, GS has become an important research topic in animal, plant and aquiculture breeding and many exciting results have been reported. In this paper, the methods for obtaining GEBVs, factors affecting the accuracy of GEBVs, and the current status of implementation of GS in livestock are reviewed. Some unresolved issues related to GS in livestock are also discussed.     

骆越文化的精粹：试析布洛陀神话叙事的起源

布洛陀神话是壮族口头传统的重要组成部分,它源远流长,是骆越文化的精粹。追本溯源,布洛陀神话应源自几千年前的骆越鸟图腾信仰,带有浓厚的骆越文化特点。它随着骆越族群的扩散而传播,在骆越后裔布依族、水族等民族之中仍有其各自的表现形态。布洛陀神话是从骆越未分化时代就保存下来的珍贵叙述。     

河南省农村居民生活用能现状及分析

通过实地走访和召开座谈会等形式,深入了解河南省农村地区农民生活用能状况,尤其是省柴节煤炉灶使用现状,评价了省柴节煤炉灶节能和环保效果,分析了目前省柴节煤炉灶推广应用的主要障碍,提出了扩大省柴节煤炉灶技术推广应用的建议.     

Influence of allele frequency on predicting animal phenotype using back-propagation artificial neural networks

To overcome the obstacle of the fascinating relation in predicting animal phenotype value, we have developed a neural network model to detect the complex non-linear relationships between the genotypes and phenotypes and the possible interactions that cannot be expressed with equations. In this paper, back-propagation neural network is used to discuss the influences of different allele frequencies on estimating the polygenic phenotype value. To ensure the precision of prediction, normalization was needed to train the prediction model. The results show that back-propagation artificial neural networks can be used to predict the phenotype value and perform very well in allele frequency from 0.2 to 0.8, when the allele frequency is very small (less than 0.2) or big (more than 0.8); however, the prediction model was not reliable and the predicted value should be carefully tested.