连片特困地区农业主导产业的比较优势演变趋势:以武陵山片区的贵州16个县为例

为连片特困地区的农业产业发展规划与政策制定提供参考,以武陵山片区的贵州16个县(区)为例,运用比较优势指数对其农业主导产业演变趋势进行定量分析。结果表明:自2000年以来,该区域农业内部各产业在国内的比较优势发生了一定程度的变化,水稻、玉米等粮食作物生产的微弱优势正在逐步丧失,而烤烟、油菜、茶叶、猪肉等少数产品生产具有比较优势,其中尤以烤烟和茶叶最为突出,且随着规模的迅速扩大,茶叶的比较优势正在进一步凸显,并逐步向集群发展转变。但是,该区域茶叶产业发展的效益优势指数偏低,表明生产效率的劣势将可能对茶产业集群发展产生不利影响,应从提高茶叶单产水平和推进茶叶产业链纵深化延伸两方面进行改善。     

山东省农产品出口竞争力实证分析

山东省是中国农业大省,山东省农产品出口额占全国农产品出口总额的四分之一左右,连续十二年来一直稳居全国第一。山东省农产品出口以水产品、蔬菜、水果、畜产品和食用油籽等劳动密集型产品为主,出口市场主要有日本、东盟、韩国、美国和欧盟。出口市场占有率、显性比较优势指数、产业内贸易指数显示,山东省农产品整体具有较强竞争力,以产业内贸易为主,贸易互补性强。在山东省五大主要出口农产品中,水产品和畜产品以产业内贸易为主,水果和食用油籽以产业间贸易为主;水果、蔬菜、水产品具有较强的国际竞争力;畜产品和食用油籽国际竞争力优势不明显。     

基于竞争优势的中国水产品出口贸易转型研究

中国是水产品生产和贸易大国,但还不是水产品生产和贸易强国。在水产品出口贸易中,由于生产成本不断上升、水产品深加工程度不高以及出口市场过于集中、国际贸易保护主义有所抬头等因素,我国水产品出口面临着愈来愈大的竞争压力。在国际竞争格局发生重大变化的背景下,保持我国水产品出口竞争力,必须通过技术进步、规模经营、质量管理和市场多元化战略,形成新的竞争优势。     

Identification of the putative ancestral allele of bovine single‐nucleotide polymorphisms

Identifying the action of natural selection from patterns of standing genetic variation has long been of interest to the population genetic community. Thanks to the availability of large single‐nucleotide polymorphism (SNP) data sets for many species and of high‐throughput SNP genotyping methods, whole‐genomic surveys to detect selective sweeps are now possible. Knowing the ancestral allele increases the power to detect selection. We present here a comparative genomic approach to determine the putative ancestral allele of bovine SNPs deposited in public databases. We analysed 19 551 488 SNPs and identified the putative ancestral allele for 14 339 107 SNPs. Our predicted ancestral alleles were in agreement with ancestral alleles detected by genotyping outgroup species for 97% SNPs from the BovineSNP50 BeadChip. This comparison indicates that our comparative genomic‐based approach to identify putative ancestral alleles is reliable.     

构筑我国水产业竞争优势策略分析

本文以迈克尔·波特的“国家竞争优势”理论为指导,强调实现中国水产业从比较优势向竞争优势的转化,并提出了构筑中国水产业竞争优势的策略框架。     

上海市水产品比较优势研究

改革开放以来，上海渔业经济的发展取得了巨大成就，但上海也为此付出了巨大代价：一是许多宝贵的水产资源逐渐衰竭；二是水产养殖导致了环境污染。上海如果要实现渔业的可持续发展，就必须注意搞好渔业产业结构的布局，发展自己的比较优势产业。文章针对如何确定上海渔业比较优势的问题详细介绍了用国内资源成本测定水产品比较优势的方法，并运用该方法测算了上海主要水产品的比较优势，旨在为上海市渔业生产结构的调整提供一定的参考和依据。     

Paralytic shellfish poison as an attractant for toxic snails

The attracting effect of paralytic shell poison (PSP) on eight toxic snail species (Polinices didyma, Natica lineata, N. vitellus, Zeuxis sufflatus, Niotha clathrata, Oliva miniacea, O. mustelina, O. hirasei) and two non-toxic species (Pomacea canaliculata, Satsuma bairdi) was investigated. Eight toxic species were reported to contain tetrodotoxin, and three out of these contained minor PSP. The minimum lethal dose of PSP in most toxic gastropods was estimated to be more than 150 MU PSP/20 g body weight, but in non-toxic gastropods was less than 15 MU PSP/20 g body weight. After the attracting test, all toxic gastropods showed significant positive linear relationship (Y=3.716X+0.363, r=0.8427) between comparative attracting variation and the toxicity reported. The relationship between PSP resistance ability and the toxicity also had a positive correlation (Y=0.91X+210.090, r=0.6803). However, the non-toxic species showed a negative response. This indicates that PSP is an attractant for toxic snails.     

阿克苏地区红枣产业比较优势分析

以阿克苏地区红枣产业发展为依托,结合比较优势理论的原理、方法,分析论证了阿克苏地区红枣产业发展的状况,根据比较优势的结果得出阿克苏地区红枣效率优势相对较弱、规模优势明显、综合比较优势呈逐年递增态势等结果,并就优化、推进阿克苏地区红枣产业发展提出了改善品种结构,提升科技含量、加强产业组织经营、实施品牌发展战略等对策和建议。     

对五株典型霉菌形态的观察和比较研究

对教学常用的五株典型霉菌,即根霉,毛霉,河内白曲(米曲霉),黑曲霉和黄曲霉经分离、纯化、培养后,对它们的形态进行了观察和比较研究。其结果是根霉的假根发达,毛霉的囊轴清晰,河内白曲的足细胞健壮,黑曲霉和黄曲霉的顶囊良好。     

不同复合肥在辣椒上的肥效试验

为了筛选出成本低、肥效高的复合肥,本研究以辣椒为试验材料,进行了5种复合肥田间试验。试验结果表明:澳特尔复合肥(N、P、K配比为25∶10∶16)和洋洋复合肥(N、P、K配比为20∶10∶10)对辣椒生长效果最好,产量最高,比对照处理1分别增产14.6%和11.2%,达到极显著水平。此两种复合肥可以在同等肥力条件下大面积推广使用。