在线评论特征对生鲜电商农产品销量的影响——来自淘宝羊肉大数据的证据

为探索在线评论对生鲜电商运营效果的影响,本研究基于信息采纳模型的框架,搭建在线评论作用于销量的理论模型,以生鲜羊肉产品为研究对象,利用Python爬虫的数据采集方式,获取淘宝平台上所有生鲜羊肉产品的月度截面数据,运用"OLS+稳健标准误"逐步回归的方法,从农产品销量的维度分析在线评论的影响,探讨评论区域中获取的评论数量、评论长度、差评数量和可视化评论对生鲜电商农产品销量的直接作用及交互效应。结果表明:在线评论数量、可视化评论能够显著提高生鲜农产品销量,差评数量则会明显降低生鲜电商的销量,而评论长度作用于生鲜农产品销量的效果并不显著。在线评论特征间的交互效应分析表明,差评能够削弱图片以及评论数量对销量的正向作用,图片能够加强评论长度对销量的积极作用,而差评的负面作用能够被评论长度进行一定程度的中和。因此,生鲜电商经营应当注重差评反映的意见,规避差评的重复出现;采用合理措施鼓励消费者进行评论,且撰写含有图片、评论字数较多的评价,均是增进信任机制、促进生鲜电商销量行之有效的办法。     

Infection-interactions in Ethiopian village chickens

Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning.     

Purified Culture Systems for Bovine Oviductal Stromal Cells

Isolated stromal cells from the ampullary and isthmic parts of bovine oviductal tissues were cultured in monolayer and spheroid (cell aggregate) systems. Prostaglandin F2α (PGF) plays a crucial role in oviductal contraction and is produced by oviductal epithelial cells in cattle. Since stromal cells of many organs produce PGF, PGF production by bovine oviductal stromal cells was investigated. After PGF synthesis was confirmed, the utility of isolation and culture methods for oviductal stromal cells was evaluated by PGF production in the present study. The homogeneity of the cells was > 99%. PGF production of the cells was increased by tumor necrosis factor-α. The stromal cells aggregated and formed a spheroid by the treatments with several reagents. PGF production was higher in the spheroid culture than in the monolayer culture. The isolation and culture methods described here will facilitate studies of the physiological function of bovine oviductal stromal cells.     

Fe2+、Cd2+互作对小麦幼苗生长发育的影响

为研究小麦生长发育过程中Fe2+、Cd2+的交互作用机制,以周麦18为材料,利用营养液培养,采用不同的Fe2+浓度(2.5、25、250 μmol/L)和Cd2+浓度(0、5、50、200 μmol/L)处理,观测小麦幼苗期的生长特性.结果表明,不添加Cd2+的处理,Fe2+浓度不同对小麦苗期根系及地上部生长的影响不同.低Fe2+时根系干物质积累随着处理时间增加而不断增加,浓度升高后根系干物质先增加后降低,根长随着Fe2上浓度升高而有所降低,少量Cd2+在一定程度上抵消了高Fe2+对小麦根系生长的抑制作用.叶绿素含量变化与根长变化表现基本一致.不同Fe2+浓度对小麦地上部干物质积累的影响与根长和叶绿素变化相反.Fe2+浓度较低时,小麦地上部干物质积累对Cd2+较为敏感,且Cd2+的存在抑制了小麦地上部的生长,降低了干物质的积累;Fe2+浓度增大,少量Cd2+的存在更有利于地上部的生长,但Cd2+浓度较高时又会抑制小麦地上部的生长.     

Breeding for improved appearance of large rainbow trout in two production environments

A quantitative genetic analysis was performed to study potential to breed for improved body shape, skin colour and skin spottiness of large rainbow trout in sea and fresh water production environments, and in different stages of growth. The results showed that heritabilities in both production environments were moderate for body shape and skin colour and very high for skin spots. For body shape and skin spots, genetic correlation between the two production environments was high (r_A≥0.90), revealing weak genotype‐by‐environment interactions across the environments. For skin colour, genetic correlation between the environments was positive (0.78) but lower than for body shape and skin spots, indicating moderate genotype‐by‐environment interactions. Genetic correlations between 2‐ and 3‐year‐old fish were high for body shape and skin spots (r_A≥0.93) and moderate for skin colour (0.85), showing that differences among families persisted strongly during growth. The positive correlations between the environments and between the ages imply that selection in fresh water environment at a single point of time should lead to favourable correlated genetic responses in the sea and at the other stages of growth.     

温州市张网捕捞能力的分析

根据2003年温州市4个地区张网渔业调查数据,运用数据包络法分析其捕捞能力。结果表明,2003年温州市张网平均利用率为89.2%。考虑了协同作用后,把占有率也当作产出,平均利用率提高至95.2%,能力产量达到109453 t。如果要保持现有产量,则可减船71艘。     

Effects of 2 training methods on stress-related behaviors of the dog (Canis familiaris) and on the dog–owner relationship

Instrumental learning plays an important role in dog–human interactions. The recent demand for pet dog training has resulted in the development of various training methods. The present exploratory study aims to compare the effects of 2 training methods on both the behavioral welfare of the dog and the dog–owner relationship: the first method is based on positive reinforcement (appearance of an appetitive stimulus), whereas the second method is based on negative reinforcement (disappearance of an aversive stimulus). The study compared behaviors linked to signs of stress and attentive behaviors toward the owner in 2 dog training schools, which used different methods. Walking on-leash activity and obeying the “sit” command were studied. The results show that dogs from the school using a negative reinforcement–based method demonstrated lowered body postures and signals of stress, whereas dogs from the school using a positive reinforcement–based method showed increased attentiveness toward their owner. However, neither method affected avoidance behaviors. This exploratory study reveals the differential effects of the 2 training methods on dogs' behaviors; it suggests that training methods based on positive reinforcement are less stressful and potentially better for their welfare.     

牙鲆"鲆优2号"不同养殖地点生长和存活性状的基因型与环境互作分析

为比较牙鲆"鲆优2号"在不同养殖地区的生长和存活性能,实验利用连续多代对生长性状和抗迟缓爱德华氏菌病性状遗传参数评估和基因组选择的结果筛选出的亲本,建立28个"鲆优2号"家系,在河北(Site 1)和山东(Site 2)进行对比养殖试验,利用混合线性动物模型对生长和存活性状进行了基因型与环境互作分析。Site 1和Site 2的平均日增重分别为1.5和1.2 g/d,养殖成活率分别为81.4%和82.2%,"鲆优2号"在两个养殖地点的生长和抗病性能均表现优异。不同养殖环境间收获体质量和存活性状的遗传相关分别为0.57(<0.7)和0.82(>0.7),说明不同养殖环境间收获体质量存在显著的基因型与环境互作效应,但是不同养殖环境间存活性状的基因型与环境互作效应不显著。研究表明,牙鲆"鲆优2号"新品种在不同养殖地点的生长和存活性能均表现良好,为保证良好的推广效果,需要对牙鲆的制种方案进一步优化,针对不同的养殖地区进行"鲆优2号"苗种生产,或培育具有普适性的"鲆优2号"苗种,保证在不同养殖环境下的快速生长和高存活率优势。     

稻瘟病菌MoYpt5蛋白互作网络预测

稻瘟病菌(Magnaporthe oryzae)共有11个假定的Rab蛋白家族成员,本文选取了MoYpt51(MGG_06241)和MoYpt52(MGG_01185)进行了生物信息学分析。通过搜索多个大型蛋白互作数据库和文献,共得到数百个与核心蛋白互作的蛋白和互作对。利用信息处理技术和高效制图平台将这些蛋白互作对构建成互作网络,得到若干个具有生物学意义的模块。结果表明,筛选得到的互作蛋白中,有的参与了蛋白降解的泛素途径(MGG_04053等)、囊泡介导的蛋白胞内运输(MGG_01238等),有的在蛋白、染色体的组装和修饰等过程(MGG_03677等)起重要作用。大部分假定互作蛋白定位于细胞质和质膜上,为其与目标蛋白互作提供了空间可能性。     

Effects of N and K fertilizers on durum wheat quality in different environments

Eight genotypes from two different genetic pools (high yielding varieties and landraces) were assessed for grain yield (GY) and for five quality traits: protein content (P), thousand kernel weight (TKW), yellow berry (YB), gluten content (G_c) and gluten index (G_i) in sub-humid and semi-arid areas using four combinations of nitrogen and potassium fertilizers during two cropping seasons. Genotype × Environment × Fertilizers (G × E × F) was significant only for protein content (p < 0.05); and E × F was found significant (p < 0.05) for all parameters. Greater quality related traits expression was noted in the semi-arid areas for both genetic pools. Excessive rainfall in semi-arid areas resulted in gluten elasticity reduction. N-fertilizers seemed to enhance protein content and to reduce thousand kernel weight. K-fertilizer, might enhance the increase in both proteins and thousand kernel weight in favorable growing conditions of water availability. Semolina yielding ability was higher in landraces as compared to high yielding varieties particularly using recommended fertilizer management. This group of cultivars showed superiority over high yielding cultivars for quantitative quality parameters.