QuEChERS结合液相色谱-串联质谱法快速测定鸡肉中磺胺类残留

采用QuEChERS方法提取和净化鸡肉样品,建立测定磺胺类12种兽药残留的液相色谱-串联质谱(LC-MS/MS)检测方法.样品经乙腈和缓冲盐包SBEQ-CA8802-B提取,提取液经净化管净化后取上清液,旋转蒸发仪减压蒸干,溶解过膜,在电喷雾离子源多反应监测(MRM)模式下进行测定,基质外标法定量.结果表明,12种磺胺...     

Agrarian Change and Labour Supply in Turkey, 1950–1980

Agrarian structures based on small peasant property can have two opposite kinds of impact on urban wages. In the first type, stable smallholder farming bringing high returns puts upward pressure on wages. In the second type, smallholder farming that does not bring sufficient returns leads to semi‐proletarianization in which workers' access to rural sources of income functions as wage subsidy and puts downward pressure on wages. This paper argues that the situation in Turkey between 1950 and 1980 fits the second type. By pointing out the factors that changed the attitude of the migrant labourers towards class struggle from relative passivity to increasing militancy, it suggests that instead of the rural ties of the emerging working class, the main reason behind the dramatic rise in urban wages in Turkey in the 1960s and 1970s was the working‐class struggle throughout the period.     

The Effects of Oil Supply and Demand Shocks on U.S. Consumer Sentiment

This paper investigates how the University of Michigan's Index of Consumer Sentiment responds to oil price shocks. While oil supply shocks play only a limited role, the effect of aggregate demand shocks is positive for the first few months and negative thereafter. A typical other oil demand shock has a significant negative impact for up to 2 years. By studying the responses of individual survey questions, we find that expectations of future inflation and a change in real household income as well as perceived vehicle and house buying conditions are the main transmission channels of oil supply and demand shocks.     

Editors’ Introduction to the Special Issue

In February 2019, the Journal of Money, Credit and Banking (JMCB) turned 50. The editors of the journal decided to celebrate this anniversary with two conferences, reflecting the two broad areas that the journal covers. A first conference on “Financial intermediation, regulation and economic policy” was held at the European Central Bank in Frankfurt/Germany on March 28–29, 2019, and addressed topics in the credit and financial intermediation fields. A second conference addressed topics in the macro-economic and monetary fields, and took place at the Federal Reserve Bank of New York on May 30–31, 2019. This Special Issue displays the best contributions to the first conference. The contributions to the second celebratory conference are published in a separate Special Issue.     

The Shadow Margins of Labor Market Slack

We use a mix of new and existing data to develop the Aggregate Hours Gap (AHG), a novel measure of labor market underutilization. Our measure differentiates individuals by detailed categories of labor market participation and uses data on their desired work hours as a measure of their potential labor supply. We show that desired hours vary widely by demographics and detailed labor force status, and that the gap between desired and actual work hours is strongly positively correlated with reported search effort. The AHG suggests a more sluggish labor market recovery since the Great Recession than either the official unemployment rate or alternative measures of labor market underutilization. Modest amounts of underutilization among the part-time employed and a substantial degree of underutilization among those out of the labor force account for the disparity. The AHG also does well in accounting for wage movements over our sample period.     

Relationship Trading in Over-the-Counter Markets

We examine the network of trading relationships between insurers and dealers in the over-the-counter (OTC) corporate bond market. Regulatory data show that one-third of insurers use a single dealer, whereas other insurers have large dealer networks. Execution prices are nonmonotone in network size, initially declining with more dealers but increasing once networks exceed 20 dealers. A model of decentralized trade in which insurers trade off the benefits of repeat business and faster execution quantitatively fits the distribution of insurers' network size and explains the price–network size relationship. Counterfactual analysis shows that regulations to unbundle trade and nontrade services can decrease welfare.     

Building Structure Design as an Integral Part of Architecture: A Teaching Model for Students of Architecture

This paper explores the place of structural design within undergraduate architectural education. The role and format of lecture-based structure courses within an education system, organized around the architectural design studio is discussed with its most prominent problems and proposed solutions. The fundamental concept of the current teaching model in the Middle East Technical University (Ankara, Turkey) is quite appropriate for the education of future architects. If we consider that the main occupation of an architect is to design, then, naturally, the design studio should be at the center of the curriculum. Since the act of designing cannot be realized without artistic skills and scientific and theoretical knowledge it is also suitable that the activities in design studios are backed up with relevant lecture courses. On the other hand, the importance of effective structural design knowledge for an architect is emphasized within the context of a country that encountered major earthquakes in the past.     

What Accounts for the Changes in U.S. Fiscal Policy Transmission?

Using vector autoregressions on U.S. time series for 1957–79 and 1983–2004, we find government spending shocks to have stronger effects on output, consumption, and wages in the earlier period. We try to account for this observation within a DSGE model featuring price rigidities and limited asset market participation. Specifically, we estimate the structural parameters of the model for both periods by matching impulse responses. Model‐based counterfactual experiments suggest that most of the changes in fiscal policy transmission are accounted for by increased asset market participation and the more active monetary policy of the Volcker–Greenspan period.     

基于改进F-N曲线的滑坡可接受风险水平研究

滑坡灾害的可接受风险水平是滑坡领域的重要研究内容之一,它常常用F-N曲线直观地表示风险频率与后果之间的关系,然而这种传统方法的参数由人为确定,主观性强,缺乏理论依据,且同一个参数不能适用多个地区和风险.以滑坡灾害的相关规范为依据,用风险矩阵的方法做衔接,绘制出3种决策态度下的滑坡灾害可接受风险的F-N曲线.相比传统的方法,改进后的F-N曲线避免了以上缺陷,使得滑坡灾害可接受风险水平的确定更加精准,同时该方法也可运用到其他领域的相关规范,来研究其可接受风险水平.