Effects and mechanisms of rural E-commerce clusters on households' entrepreneurship behavior in China

The vigorous development of rural E-commerce reveals a powerful pattern of economic clustering. Recently, many Taobao Villages have formed in more than 80% of the provinces in rural China, and increasingly households are using E-commerce for entrepreneurial innovation in Taobao Villages. However, the effect and mechanism of the Taobao Village model on households' entrepreneurship behavior remain unclear. Using survey data and structural equation modeling, we analyzed the factors of households' entrepreneurship behavior and investigated the mechanism of rural E-commerce clustering on the households' entrepreneurship behavior in Taobao Villages. The results show that: (1) rural E-commerce clusters stimulated entrepreneurial enthusiasm and increased entrepreneurial behavior; (2) local resource endowment, entrepreneurial atmosphere and culture, threshold for entrepreneurship, and demonstrative leadership had significant positive effects on households' entrepreneurship behavior; (3) external environmental support, including government, and external business environment support had significant positive effects on E-commerce development. All these results indicate that rural E-commerce clusters promote households' entrepreneurship behavior.     

大蒜根腐病根际土壤真菌群落结构及多样性分析

研究旨在解析根腐病发生时大蒜根际土壤真菌群落结构,明确大蒜根腐病与根际土壤真菌群落多样性变化的关系,探明根腐病发生的微生态机制,为病害的防控提供理论基础。以新疆连续3年的大蒜根腐病发病田的根际土壤为研究对象,采用高通量测序方法对大蒜根际土壤总DNA的真菌ITS区序列进行大规模测序分析。结果表明,与健康对照相比,在门的水平上,子囊菌门和接合菌门真菌是大蒜根腐病根际土壤的优势真菌类群,其中高水平的子囊菌门菌群与病害发生有着密切的关系。在属的水平上,注释获得137个属,其中19个属与大蒜根腐病有较大的相关性。镰刀菌属真菌数量在病土中高于健康对照。随着连作年限的延续,根腐病的发生愈发严重,土壤中真菌群落的Shannon指数、Simpson指数、真菌属的数量逐年降低,大蒜根腐病的发生与植株根际真菌群落组成及多样性密切相关,土壤真菌类群的平衡和多样性改变是根腐病发生的一大诱因。     

外源硅调控葡萄生理特性对低温胁迫的响应

本研究以大田葡萄品种‘梅鹿辄’为试材,采用大田喷施硅酸钾与室内低温处理相结合的方法,测定不同温度下葡萄叶片生理指标的变化,研究外源硅酸钾调控葡萄生理特性对低温胁迫的响应,探讨其提高葡萄抗寒性可能的作用机制。结果表明:低温胁迫下葡萄Inv活性被抑制,而其它指标则升高;喷施硅酸钾可显著降低低温胁迫下葡萄叶片的MDA含量,且当硅酸钾浓度为0.75%时对低温的损伤缓解作用最大;而脯氨酸、可溶性蛋白和可溶性糖含量、Inv、SPS活性及SS净活性均随硅酸钾浓度的升高而显著提高,但是可溶性蛋白含量在硅酸钾浓度为0.50%时最大,其它指标均在浓度为0.75%时最大;通过葡萄叶片各抗寒指标的隶属度值与综合评价指标看出,始花期0.75%的硅酸钾处理后葡萄抗寒性最强。综合分析,喷施硅酸钾可提高低温胁迫下葡萄叶片渗透调节物质含量,加快蔗糖转运及代谢速率,缓解活性氧累积,增强其耐寒性。     

论和谐社会目标下的大学生思想政治教育

构建社会主义和谐社会迫切需要加强和改进大学生思想政治教育。针对大学生思想状况的实际,从构建和谐社会的高度出发,加强和改进大学生思想政治教育,要求牢固树立以学生为本的理念,确立以服务和谐社会建设为目标,重视发挥校园文化的重要育人功能,坚持日常教育与网络教育相结合,坚持解决思想问题与解决实际问题相结合,坚持思想政治工作与心理健康教育相结合。     

Reproductive characteristics and variations in the biochemical composition of Neptunea arthritica cumingii crosse through embryonic development

The copulation, egg laying, embryonic development and changes in amino acids and fatty acids in Neptunea arthritica cumingii during embryogenesis were studied to understand the embryo development process and nutritional requirements in the early life phase. The results showed that N. arthritica cumingii has direct development within the egg capsule and the development of embryos was classified into five stages: cleavage, egg swallowing, protoconch forming, shell development and juvenile. Embryos develop through the provision of nurse eggs as an extra‐embryonic source of nutrition. As development continued, the body of the embryo began to coil. After about 70–80 days, young N.arthritica cumingii started to emerge through a hole underneath the capsule. Biochemical results showed that the total amount of amino acids showed a decreasing trend as embryonic development progressed. The content of all nine essential amino acids decreased significantly from the egg‐swallowing stage to the post‐larva stage (p < .05). Concentrations of five of the seven nonessential amino acids also showed a decreasing trend from the egg‐swallowing stage to the post‐larva stage; the exceptions were Ala and Gly. Gly is the only amino acid that consistently increased in concentration during the development process. Most fatty acids increased after the eggs hatched, except for C20:1, C20:2, C22:5 and C22:6 (docosahexaenoic acid, DHA). The data in this study may provide a starting point for the formulation of well‐balanced early‐stage larval diets, although N.arthritica cumingii is still in the exploration stage.     

Effects of body size and water temperature on food consumption and growth in the sea cucumber Apostichopus japonicus (Selenka) with special reference to aestivation

To investigate the effects of body size and water temperature on feeding and growth in the sea cucumber Apostichopus japonicus (Selenka), the maximum rate of food consumption in terms of energy (C_maxe; J day^?1) and the specific growth rate in terms of energy (SGRe; % day^?1) in animals of three body sizes (mean±SE) – large (134.0±3.5 g), medium (73.6±2.2 g) and small (36.5±1.2 g) – were determined at water temperatures of 10, 15, 20, 25 and 30°C. Maximum rate of food consumption in terms of energy increased and SGRe decreased with increasing body weight at 10, 15 and 20°C. This trend, however, was not apparent at 25 and 30°C, which could be influenced by aestivation. High water temperatures (above 20°C) were disadvantageous to feeding and growth of this animal; SGRe of A. japonicus during aestivation was negative. The optimum temperatures for food consumption and for growth were similar and were between 14 and 15°C, and body size seemed to have a slight effect on the optimal temperature for food consumption or growth. Because aestivation of A. japonicus was temperature dependent, the present paper also documented the threshold temperatures to aestivation as indicated by feeding cessation. Deduced from daily food consumption of individuals, the threshold temperature to aestivation for large and medium animals (73.3–139.3 g) was 24.5?25.5°C, while that for small animals (28.9–40.7 g) was between 25.5 and 30.5°C. These values are higher than previous reports; differences in sign of aestivation, experimental condition and dwelling district of test animals could be the reasons.     

草鱼肝微粒体的提取及CYP酶活性的测定

CYP酶代谢是药物生物转化的主要途径,其数量和活性大小直接影响药物在体内的活化与代谢。我们对草鱼肝微粒体CYP酶含量及其活性进行了初步研究,以差速离心法提取草鱼肝微粒体,以CO还原差示光谱法测得CYP酶及细胞色素b5含量分别为0.619±0.102 nmol/mg、0.264±0.042 nmol/mg。以7-乙氧异吩噁唑酮-O-脱乙基反应、苯胺-4-羟化反应、氨基比林-N-脱甲基反应作为CYP1A、CYP2E、CYP3A的探针反应,测得EROD酶活为0.043±0.004 nmol/mg/min,ANH酶活为0.028±0.002 nmol/mg/min,AMND酶活为0.207±0.035 nmol/mg/m in。结果表明草鱼肝微粒体中CYP酶发育完好,并且具有参与药物代谢的3种主要亚型活性,其含量与活性大小与其它实验动物相差较大。本实验的方法与结果为草鱼CYP酶的系统研究提供可靠手段,最终为指导水产合理用药提供理论依据。     

紫外线诱变建立草鱼抗出血病病原病毒的AHZC88细胞株

通过UV对草鱼出血病病原病毒敏感的草鱼ZC 7901细胞株反覆诱变,获得了对出血病病原病毒具有抗性的AHZC 88细胞株。经生物学特性测定,AHZC 88细胞的染色体2n=48,温度适应范围4°～38℃,最适生长温度27℃,分裂指数在36小时时达最高值。经病原病毒的人工侵染等试验表明,AHZC 88细胞不受草鱼出血病病毒感染。在电镜切片观察中,细胞内不见病毒颗粒。LDH同工酶分析,比敏感细胞少1条酶带。     

草鱼出血病的病原研究

草鱼出血病的病原研究,始于50年代。1978—84年,分离到一种病原病毒,定名为草鱼呼肠孤病毒或鱼呼肠孤病毒。本文报道从出血病病鱼组织的电镜研究中发现两种病毒颗料,一种即是呼肠孤病毒,另一种是20-30nm大小的病毒。经病毒的核酸分析,前者是双股RNA病毒;后者为单股RNA病毒。用分离到的这两种病毒分别注入1足龄健康草鱼,可发生两类不同症状的出血病;呼肠孤病毒主要导致“肠出血型”症状;另一种病毒(经初步鉴别属于小RNA病毒科病毒)主要导致“肌肉出血型”出血病。由此,可以证实两种病毒都是草鱼出血病的病原病毒,同时也初步解释出现两种不同症状出血病的原因。     

A SCAR marker linked to the N gene for resistance to root knot nematodes (Meloidogyne spp.) in pepper (Capsicum annuum L.)

The root-knot nematodes (Meloidogyne spp.) are important nematode pests and cause serious diseases in pepper in the world. No molecular markers linked to the nematodes resistance N gene have been reported. In this paper, ‘Carolina Wonder’ (Capsicum annuum L.), a sweet pepper line resistant to root-knot nematode with N gene, ‘20080-5-29’ (C. annuum L.), an inbred line susceptible to root-knot nematode with good horticultural characteristics, and their F₂ progeny with 320 individuals were used as materials. Evaluation of resistance and susceptibility of parental lines, F₁ and F₂ progeny inoculated with root-knot nematodes (Meloidogyne incognita) were carried out. ‘Bulked segregant analysis’ method was used to search for polymorphic markers from 512 pairs of AFLP primers. Based on the assessment of resistance and susceptibility and polymorphism of the AFLP marker in F₂ population, the genetic linkage distance between the AFLP marker and the N gene was estimated. One AFLP marker E39/M41-339 was obtained and transferred to a SCAR marker amplifying a 315 bp DNA fragment linked to the N resistant allele and a 331 bp fragment linked to the N⁺ susceptible allele. The distance between the molecular marker and the nematodes resistance N gene is 6.3 cM. This research delivered a valuable tool for the marker assisted selection of nematodes resistance in pepper.