SPME-GC-MS分析皖西白鹅蛋挥发性成分

以皖西白鹅蛋的熟蛋清和熟蛋黄为研究对象,采用顶空固相微萃取-气相色谱-质谱联用技术对皖西白鹅蛋的挥发性化合物进行测定和分析。结果表明,从皖西白鹅蛋的熟蛋清、熟蛋黄中分别检测出48种、24种挥发性化合物,鉴定到的挥发性物质主要包括烷烃类、烯烃类、醇类、酮类、酯类、含硫化合物、杂环类及硅化物等。研究结果为鹅蛋的品质和风味提供了重要的信息,也为鹅蛋的生产加工方式提供一定的参考。     

Consumer Preferences for ‘Localness’ and Organic Food Production

While organic food is based on well-defined production criteria, the criteria for ‘local’ food are less clear. This study investigates the preferences and trade-offs of distinct consumer segments relative to organic production and several dimensions of local food (sales channel, size of company, and geographical location of animals used in the production). The analysis is based on a quantitative survey of 505 Danish consumers and a choice experiment involving beef salami. Data were analyzed in a principal component and a latent class analysis. We identify five consumer segments whose preferences for organic and local product attributes differed substantially. Most respondents considered geographical proximity in the raising of cattle to be the most important attribute and a third of the consumers were willing to pay a premium for organic salami. The segmentation provides more detailed information about stated consumer behavior than what is typically elicited when considering only average consumer behavior.     

农户减少化肥用量和采用有机肥的意愿研究——基于洱海流域上游面源污染防控的视角

[目的]过量施用化肥导致水体富营养化是造成洱海流域上游面源污染的主要原因之一,调查分析农户减少化肥用量和采用有机肥的意愿有助于了解其调整施肥结构的行为。当前研究忽视了农户减少化肥施用强度和采用有机肥的意愿间的替代性,未能开展联立研究。[方法]基于洱海流域上游397个水稻种植户的问卷调查数据,通过Bivariate-Probit模型对农户减少化肥用量和采用有机肥两种意愿进行分析。[结果]年龄负向影响农户减少化肥量的意愿,农户对有机肥好处的认知正向影响其减少化肥量的意愿,农户参加农业社会化服务对其减少化肥用量和采用有机肥的意愿均产生正向影响,相比之下,对农户采用有机肥意愿的促进作用更大。[结论]引导农户参加农业社会化服务以及加强宣传和培训,提高农户对有机肥作用的认知可能是加强其减少化肥用量和增加有机肥施用量意愿的有效途径。     

The Impact of Sustainability Aspects in the Meat Sector: A Cluster Analysis Based on Consumer Attitudes and Store Format Choice

Several consumer studies have shown considerable market potential for sustainable meat products, however, their markets shares are still marginal. In Germany, the sustainable aspects “organic,” “local origin,” and “animal welfare” are of special interest. To obtain a precise overview of potential target groups for these meat categories and their choice of store format, 620 German consumers were surveyed on their attitudes toward sustainable meat production and their shopping behavior. First, target groups based on consumers’ attitudes were identified by cluster analysis, taking into account possible overlaps. Consumers were also clustered by their store format choice and their preferred type of meat packaging. A cross tabulation of the results then provided insights into which store format and type of meat packaging is preferred by the target groups for sustainable meat products. Due to overlaps found in the target groups, the existence of important subgroups was shown. Amongst the target groups, only a slight preference for unpackaged meat products was found. Basically, the offer of sustainable meat products appears of interest for all store formats, with particular emphasis on supermarkets. The results of this study can support producers and retailers developing new and tailored marketing strategies for sustainable meat products.     

Antecedents of Perceived Value and Repurchase Intention of Organic Food

The rise of the natural and organic products market follows a global trend of increasing demand largely due to the growth of environmental awareness and the concern of having a healthier diet. Thus, the objective of this study is to propose and test a theoretical model based on antecedent constructs of perceived value and repurchase intention on the consumption of organic products. The results, based on 256 consumers of organic products, confirm the positive relationship between environmental awareness and perceived quality, healthy consumption, and perceived price fairness. Moreover, they underpin the influence of healthy consumption, perceived price fairness and perceived quality on perceived value, and lastly, the influence of perceived value on repurchase intention. Therefore, this study can help practitioners and consumers comprehend in a more systematic way the buying behaviour of this food category.     

"利剑斩污"行动下石家庄市挥发性有机物的污染特性变化研究

为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。     

Are international environmental policies effective? The case of the Rotterdam and the Stockholm Conventions

This is the first paper to show that participation in an international environmental agreement has some effectiveness. Our identification strategy consists of applying difference-in-differences techniques in a panel data framework to various levels of data aggregation. We find that ratification of the Rotterdam Convention (RC) and the Stockholm Convention (SC) leads to a reduction in trade of hazardous substances from OECD to non-OECD countries. In particular, we find that when the exporter ratifies the RC, there is a reduction in the import of hazardous chemicals of about 7 percent. In the case of the SC, the results show significant reductions of around 16 percent in trade shipments of persistent organic pollutants. This reduction is more than double the effect found for the RC, which was expected due to a more restricted obligation imposed by the SC convention.     

Factors Influencing Organic and Fair Trade Coffee Growers Level of Engagement with Cooperatives: The Case of Coffee Farmers in Mexico

We study the factors influencing the percentage of organic and fair trade certified coffee sold through a cooperative by growers of five cooperatives in Mexico. The percentage of coffee sold through the cooperative was used as a proxy of growers’ engagement with a cooperative. Using factor analysis and a fractional probit regression, we evaluated the proposition that the level of engagement can be explained by transaction cost economics, social norms and connections, and farmer and farm business characteristics. We found that farm size, uncertainty regarding cooperative time of payment to the members and cooperative commitment on price to be paid negatively influence the level of engagement. In contrast, asset specificity, relational commitment, and price have a positive impact on engagement. Our results may help cooperatives and policy makers to build strategies aiming to increase this level of engagement. This is relevant because lower grower engagement has been found to be positively correlated with weak performing cooperatives.     

民办院校有机化学实验多元化教学模式探索

民办院校把有机化学实验作为有机化学教学的重要组成部分,多元化教学模式主要从教学方法与手段、教学内容、学习方式、考评体系等方面进行多元化教学模式探索。建立以微课视频、翻转课堂、问题引导,依托基础性实验、综合型实验和创新型实验,依托多元化信息化的教学手段雨课堂、虚拟仿真情景模拟实验、超星尔雅平台,融合多种教学方法,结合“线下”翻转课堂,建立多元化教学模式。这种多元化教学模式能有效提高学生的学习主动性和创新能力。     

Cooperation and Competition in the Context of Organic and Mechanic Worldviews – A Theoretical and Case based Discussion

In this study we argue that there is an interconnection between; the mechanistic worldview and competition, and the organic worldview and cooperation. To illustrate our main thesis we introduce two cases; first, Max Havelaar, a paradigmatic case of how business might function in an economy based upon solidarity and sustainability. Second, TINE, a Norwegian grocery corporation engaged in collusion in order to force a small competitor out of the market. On the one hand, in order to encourage market behaviour that integrates economic, societal and environmental values we find that transparent cooperation within a context of an organic worldview takes care of important intrinsic as well as instrumental values. On the other hand, we find evidence for asserting that cooperation based upon a mechanistic worldview, typically leads to group egotistical consequences undermining the long term common good.