曲酸摇床发酵与发酵罐发酵工艺参数的比较

通过单因素及正交实验,比较高产米曲霉在摇床培养与发酵罐培养中生产曲酸的发酵工艺参数。结果表明,在温度为23℃、发酵天数为9 d、接种量为25%、菌龄为96 h时,摇床发酵的曲酸产量达到最高,最高可达98.6 g·L-1;而发酵罐培养的最佳工艺条件是温度23℃、发酵天数4 d,接种量15%,菌龄96 h时,此条件下曲酸产量可达到99.6 g·L-1。本研究为工业化生产曲酸提了供理论依据。     

基于西门子PLC除尘器粉尘防爆危险源信号检测及预警系统的研究

研发适用于滤袋式除尘器粉尘爆炸危险源信号的实时检测及预警系统。该系统综合应用工业控制、PLC控制、智能测控终端无线传输、云平台数据管理等技术。采用传感器分别监测除尘器运行时的进出风口压差、除尘器运行状态、高压脉冲喷吹压力和箱体温度。当监测信号不在系统预设的合理范围时,PLC输出就地预警信号,监测信号也可通过无线传输模块上传到云平台。运用云平台的数据分析功能,实现除尘器运行状态系统化监测和综合管理。     

大数据与监视型资本主义

本文首先介绍了监视型资本主义的概念,描述信息时代的资本是如何通过收集个人数据,无视私隐,筛选用户,在不受法律监控的情况下进行帝国式扩展的。进而,本文提出数据的附身性和数码资本错位这两个特征,用以分析技术如何在数据收集和应用上激活数据的私人财产属性,以及资本如何利用价值错位和技术优势去诱使用户参与这一资本增值的进程。数据的附身性揭示了个体如何被卷入大数据时代的生产关系,数码资本错位揭示了资本具体实现监视型资本主义的技术。这两个概念将完善监视型资本主义这一理论体系,进一步展现这个时代隐蔽的不平等状况。     

上海市大力发展农村金融服务的SWOT分析

运用SWOT方法对上海市大力发展农村金融服务进行分析。分析结果可知上海在大力发展农村金融服务时存在政策、地理位置优势;但在法律和农户金融意识方面存在劣势;此外,上海市既面临"互联网+"与金融合作、潜在需求大的机遇,也面临违约和诈骗风险的威胁。     

发展林下经济能否保护森林资源?--基于江苏省的经验证据

发展林下经济作为集体林权制度改革的配套政策之一,能否发挥生态优势保护森林资源是检验其政策绩效的重要标准。在分类剖析不同林下经济模式对森林资源的影响机理基础上,利用江苏省81个县林下经济发展经验证据,构建OLS模型进行实证分析。研究发现,发展林下经济有助于提高森林面积,其中林下养殖与森林景观利用模式的作用突出。     

Stock market dependence in crisis periods: Evidence from oil price shocks and the Qatar blockade

This paper examines the correlation and the dependence patterns of the Qatar stock market with other markets using copula statistical theory and exploiting new datasets covering the period August 1998 to June 2018. To examine the crisis –specific change in the average degree of dependence we decomposed the data into the time periods before and after oil price shocks and the 2017 political crisis among the Gulf Cooperation Council members (i.e. the Qatari blockade). Our findings from the static copula modelling show that the correlations between the Qatari and the other stock markets significantly change after the oil price and the blockade crisis as well. The degree of change in the correlation is time varying and differs from county-group to another. Moreover, our findings reveals that the 2008 global financial crisis has a stronger impact than the price shocks and political crisis. The findings of the paper are of interest and allow for formulating a reliable and dynamic portfolio design framework for investors and risk managers.     

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。     

Direct intervention or indirect support? The effects of cooperative control measures on farmers’ implementation of quality and safety standards

In recent years, labor-intensive agricultural products from developing countries have exhibited inferior performance in international trade due to quality and safety incidents, among which pesticide residue is a major issue. Aiming to improve food quality and safety in the context of cooperatives, we introduced three categories of control measures: outcome control, process control and social control. Based on the Pre-Harvest Interval Standard (PHIS), we selected three indices, farmers’ implementation rate of PHIS, absolute distance to PHIS and relative distance to PHIS, to evaluate appropriateness of pesticides use, reduction of pesticide residue and safety improvements of agricultural products. By using random sampling survey data, we empirically analyzed the marginal effects of control measures and their combinations on food quality and safety standards. The empirical results show that implementing process control, namely, unified production standards or supply of unified agricultural inputs, can comprehensively improve farmers’ implementation rate of PHIS, absolute distance and relative distance to PHIS respectively by 34.9%, 3.2 days and 46.0% on average. While the effects of outcome control (safety inspection) and social control (bonus-penalty incentive or training) are restricted to other measures. Therefore, we suggest cooperatives should take farmers’ features, implementation conditions and the effects of control measures into consideration in order to make a sustainable management plan for improving food quality and safety and enhancing competitiveness in international markets.     

Are China’s regional agricultural productivities converging: How and why?

This article tests the hypotheses of convergence to a single level of total factor productivity (TFP), and a steady state of TFP growth rate in China’s agricultural sector. Based on multilateral TFP estimates we found that China’s agricultural sector has rebounded in recent years from a slower TFP growth in the 2005–2007 period. While convergence test results confirm a “catch-up” effect that provinces with lower TFP levels tend to grow faster than others, estimated rates of β convergence are conditional on how we capture the heterogeneity effect across regions. The rates of β convergence range from 0.016 to 0.039 under different model specifications. Estimates show that higher growth rates of educational attainment, R&D, and intermediate goods density (per unit of labor) can enhance TFP growth. Unfortunately, there is no evidence of an overall σ convergence, indicating that TFP levels are not converging except in the South region. It implies that to catch up with leading provinces, it would require extra efforts for those lagging behind by increasing their region-specific research investment, promoting rural educational attainment, and enhancing embodied technical change.     

Neighbors and friends: How do European political parties respond to globalization?

This paper explores the relationship between globalization and party positions accounting for potential differences between left- and right-wing parties. The analysis is based on a panel model of 36 political parties in 18 Western European countries between 1970 and 2015. We find that right-wing parties move leftward in response to globalization, while left-wing parties do not alter their position. Additionally, we find that ideological party positions are affected by foreign parties’ positions of the same ideological bloc. These findings indicate that there is a convergence towards the left of the political spectrum due to right-wing party moderation.