电感耦合等离子体发射光谱法测定蜂蜜中7种矿物元素的含量

为了快速直接测定蜂蜜中多种矿物元素的含量,采用电感耦合等离子体发射光谱(ICP-AES)法建立了同时测定蜂蜜中钙、钾、镁、钠、锌、铁、铜7种矿物元素含量的方法,考察了方法的标准曲线线性关系、检出限、精密度和准确度,讨论了前处理方法、不同产地以及蜜源植物种类对各元素含量的影响。结果表明:线性相关系数达到0.999 9以上,方法检出限为0.003～0.030 mg/L,相对标准偏差低于2%,回收率为88.66%～105.31%;不同产地的洋槐蜜中,河北洋槐蜜的钙、钾含量明显高于其他地区,广西洋槐蜜的钠、铁含量最高;不同蜜源植物的蜂蜜中,河北枣花蜜的铁含量最高,野生蜜中各种矿物元素都较为丰富。电感耦合等离子体发射光谱法可以快速、同时测定蜂蜜中多种矿物元素含量,方法简便易行,结果准确可靠,可为蜂蜜品质鉴定以及人们对蜂蜜的合理选择提供参考。     

基于信号博弈的土地使用权出让中围标“蜜罐”行为的分析

研究目的:依据土地使用权招标出让活动的特征,构建围标"蜜罐"行为的动态贝叶斯博弈模型,找出促使均衡结果合理化的因素变化差异和关系。研究方法:信号博弈。研究结果:(1)由分开均衡的求解可知,在土地使用权招标中,当招标人看到投标人报低价时将检查,看到投标人报高价时则不检查;投标人围标时将选择报低价,不围标时将报高价。(2)由合并均衡求解可知,无论投标人围标与否,投标人报低价时,此博弈有两个完美贝叶斯均衡。研究结论:为遏止投标人进行围标合谋这一"吃蜜罐"的行为,要增加围标成本、合理控制检查成本、降低投标人预期收益和完善惩罚形式、加大惩罚力度。     

Selling Together: The Benefits of Cooperatives to Women Honey Producers in Ethiopia

Smallholder farmers in developing countries encounter multiple barriers in access to inputs and technology, which prevent them from reaping the benefits from market participation. Women farmers face additional constraints due to gender norms that further limit their engagement in productive activities. While collective action has been shown to improve access to markets and economic outcomes for farmers overall, the evidence on the effects of cooperative membership for women smallholders remains limited. We investigate empirically the economic benefits of collective action for women farmers in the honey sector in Ethiopia. Relying on a rich data set on women honey producers, both cooperative members and non‐members, we evaluate the effects of belonging to a cooperative on three outcome variables through coarsened exact matching and regression analysis. Our results indicate that cooperative membership significantly increases the market price and the production quantity and, while the average effect on the share of product marketed is statistically insignificant, significant differences emerge for women with given characteristics. These results are shown to be robust to a number of tests that address biases from selection on observables and unobservables. An analysis of the heterogeneous effects of household membership in multiple groups finds that membership of self‐help groups or farmer associations amplifies the positive outcomes from belonging to a formal cooperative. Finally, qualitative findings derived from the same communities indicate self‐reported improvements in agency and self‐esteem among women members, thus reinforcing the importance of the quantitative findings.     

Detecting origin fraud with trade data: the case of U.S. honey imports*

Following the 2001 U.S. imposition of antidumping tariffs on imported honey from China and Argentina, industry press noted patterns of trade suggesting that honey was being transshipped to circumvent tariffs, origin fraud that was later uncovered in criminal cases. This article presents three approaches that use trade and production data to flag countries for possible instances of origin fraud and then compares these countries with those implicated in criminal cases and media reports. In our preferred empirical method, we also find that countries with higher corruption scores are more likely to show increases in suspicious trade patterns following the tariffs.     

中国蜂蜜在日本市场的需求弹性

日本是中国蜂蜜出口的最大市场,占中国蜂蜜出口总额的40%,对中国蜂蜜贸易的发展至关重要。本文以日本蜂蜜市场1995年5月至2004年12月的进口数据为基础,运用近似线形需求系统模型(LA-AIDS)估计中国蜂蜜在日本市场的收入弹性、自价格弹性和交叉价格弹性,分析中国蜂蜜在日本市场的贸易地位与竞争策略。研究结果表明,在日本蜂蜜进口市场,中国蜂蜜的价格对来自阿根廷的蜂蜜进口量有较大的影响力,但实施价格战会使中国蜂蜜的利润损失大于阿根廷。最优的竞争策略是努力维持市场份额,通过质量与安全水平的提升来获取较高的价格和利润率。     

绿色技术壁垒影响安徽蜂蜜出口的成因与对策

近年来安徽省蜂蜜产品的出口呈现量减价扬的趋势,其主要出口市场实施绿色技术壁垒增加了蜂蜜出口的难度,从经济学角度阐释遭遇绿色技术壁垒的成因,提出政府应采取积极措施,强化行业协会的功能,控制蜂蜜产品源头质量的建议。     

上海东源公司就蜂蜜反倾销复审中价格计算问题告美国商务部案评析

美国对华蜂蜜反倾销已历时14年多。上海东源公司等不服美国商务部在第二次行政复审中对替代国价格的认定,在美国国际贸易法院提起诉讼。本文在介绍基本案情的基础上,对美国国际贸易法院的判决做了归纳,并对本案涉及的主要法律问题进行了评论。     

安帮消蜂蜜出口中的绿色技术壁垒及对策

在综述蜂蜜出口的技术贸易壁垒的相关理论的前提下,通过对安徽省蜂蜜产品的出口现状的描述,分析了绿色技术壁垒对安徽蜂蜜出口的现实影响,并就政府要进一步加强蜜源植物的保护力度、督促企业按有关规定加强原料基地建设等对策进行了思考。     

International honey laundering and consumer willingness to pay a premium for local honey: an experimental study

Fraudulent activities in the international honey market affect 10% of food, and cost the global food market $50 billion per annum. Although many developed countries have created regulations to combat food fraud, illegally imported honey, especially originating from China, still enters through transshipments and relabelling to mask its true origin. This honey laundering poses a health risk to consumers, as Chinese honey potentially contains illegal and unsafe antibiotics and high levels of herbicides and pesticides. We analyse whether information about the negative health impacts of laundered honey increases the proportion of consumers willing to pay a premium for local fraud‐free honey. Using a laboratory experiment, we find when consumers are given honey laundering information, their willingness to pay a premium for local fraud‐free honey increases by as much as 27 percentage points. Our findings suggest that by conveying honey laundering information and guaranteeing their honey is fraud‐free, producers can potentially increase revenues and reduce the prevalence of food fraud. Our results further show that consumers' preference for various honey characteristics and age also influence the probability of paying a premium for local honey.     

LC-MS法快速测定蜂蜜中甲硝唑地美硝唑和洛硝哒唑

建立了液相色谱-串联质谱法(LC-MS)快速测定蜂蜜中甲硝唑、地美硝唑和洛硝哒唑的检测方法。以水为提取溶剂,加入适量甲醇,乙酸乙酯萃取,经浓缩、复溶、过滤,通过LC-MS法检测枣花蜂蜜中3种硝基咪唑类药物残留,以外标法定量。测定当加入甲硝唑量分别为2.5μg/kg、10.0μg/kg和50.0μg/kg时,回收率分别为85.2%、82.7%和81.0%,当加入地美硝唑量分别为5.0μg/kg、20.0μg/kg和100.0μg/kg时,回收率分别为92.3%、88.4%和88.7%,当加入洛硝哒唑量分别为5.0μg/kg、20.0μg/kg和100.0μg/kg时,回收率分别为92.3%、73.9%和76.6%。甲硝唑、地美硝唑、洛硝哒唑检出限分别为0.1μg/kg、0.2μg/kg和0.2μg/kg。结果表明:该方法稳定性好,准确度高,操作简单、快速,可以满足低残留量的检测要求。