多层微波集成电路中微带线层间互连仿真

针对多层微波集成电路设计的微带线层间互连问题，介绍了垂直通孔互连、垂直带条互连和层耦合过渡互连三种高性能的互连方法，并且采用三维电磁仿真软件HFSS对这三种互连结构进行了建模和仿真。仿真结果表明，垂直通孔互连和垂直带条互连在0.1～25 GHz的频宽范围内，回波损耗S11<-20 dB，插入损耗S21>-1 dB，互连性能优良，而层耦合过渡互连在20～68 GHz内回波损耗S11 <-20 dB，插入损耗S21>-1 dB，具有在毫米波频段实现互连的潜力。     

Ethnic patterns of returns to education in Bulgaria

It is widely accepted that disparities in education contribute to the poor labour market outcomes experienced by ethnic minority groups and consequently to their poverty. In this article, I analyse differential educational benefits in Bulgaria and compare returns to education for the Roma minority with the majority population and the Turkish minority. I show that both ethnic minority groups have lower education levels and employment rates than the majority population and that they also have lower returns to education. This result could be related to minorities' lower education quality as well as to discrimination in the labour market. Integration policies should thus aim to improve employability and labour market competence of vulnerable groups starting from school.     

The contribution of Western fast food to fast-growing body mass in China

The westernization of Asian countries has led to the rapid expansion of Western-style fast-food restaurants, which are believed to be fueling an unprecedented rise in body mass in these countries. This study tests this belief using longitudinal data from China. Exploiting the opening of a Western-style fast-food restaurant in a particular community, we conduct a transition analysis to make a more convincing causal interpretation than the standard cross-sectional or fixed-effects approach. Considering several measures of fatness, we find no robust evidence of Western fast food having a substantial effect overall, but there is some indication of effect heterogeneity.     

How should Engel's law be formulated?

Engel's law expresses a “negative stochastic association” of income and the proportion of income that is spent on food. However, there are many quite different notions of “negative stochastic association” and consequently there are different ways of defining Engel's law. We relate these different concepts to Engel's original statistical analysis and show that one must give credit to Engel for the first non-parametric statistical analysis of budget-data.     

Stock Price Index and Exchange Rate Nexus in African Markets

This paper examines the relationship between stock price index and exchange rate in six African markets using monthly data for the period January 2007 to October 2015. A quantile regression approach is used. This methodology is shown to perform better than the ordinary least squares estimators, particularly when the conditional distribution is heterogeneous. Our empirical evidence reveals an interesting pattern in the association of these two financial markets in Africa, which shows that the negative relationship between stock and foreign exchange markets is more apparent when exchange rates are extremely low or high. The negative relationship between the two variables is in line with the portfolio balance effect.     

User Fee Abolition and the Demand for Public Health Care

This research examines the effect of the abolition of user fees in South Africa, a policy implemented in 1994 for uninsured children under the age of six and the elderly uninsured, as well as pregnant and nursing mothers. The analysis focuses on the implementation of the policy and the use of curative public healthcare services by children following strict and fuzzy regression discontinuity designs. The estimates point to statistically insignificant average and local average policy effects, even though the policy appears to have been implemented reasonably effectively, albeit imperfectly. In other words, the policy did not, on average, affect the use of curative public healthcare, at least for those children who should have benefited from the policy.     

Bancarization and violent attacks from guerrilla and other illegal groups in Colombia

Income shocks affect violence through the opportunity cost and rapacity effects. Existing studies focus on the impact of transitory shocks, especially commodity price innovations. This paper builds on this literature and studies the causal effect of permanent income shocks on armed conflict in Colombia. Using a rich dataset reporting all guerrilla and other armed groups' attacks by municipality between 2009 and 2014 and information on the provision of banking services, it shows that increasing bancarization leads to reductions in violence. These results have important implications for public policy in countries with a long history of violence. They suggest that promoting financial inclusion is useful for reducing conflict.     

Geography of Italian student mobility: A network analysis approach

Understanding the phenomenon of intra- and international student mobility has become increasingly relevant to the organization of tertiary education systems. Using microdata information provided by the Italian National Student Archive on the cohorts of students enrolled at university in the academic years 2011–12 and 2014–15, we consider a network analysis approach to investigate the incoming and outgoing student flows between territories and universities. More specifically, the paper aims to shed light on the dynamics of Italian student mobility networks at both the bachelor's and master's degree levels by considering attractiveness indicators combined with network centrality measures, clustering techniques for network data and explanatory models. We analyze the partition of the global network structure by means of blockmodeling analysis and we explain the determinants of the differences among universities in attracting students adopting a quantile regression analysis.     

WHICH FISCAL MULTIPLIERS ARE REGIME‐DEPENDENT? A META‐REGRESSION ANALYSIS

We analyse whether estimated multiplier effects are systematically higher if the economy suffers a downturn. For that purpose, we conduct a meta‐regression analysis on a unique data set of 98 empirical studies with more than 1800 observations on multiplier effects and control for regime‐dependence of the multiplier. We find that spending multipliers are much higher (by about 0.7–0.9 units) during a downturn. Tax multipliers are not sensitive to the economic regime, and generally lower than spending multipliers. Finally, for all spending categories other than government consumption, the multiplier significantly exceeds one during downturns.     

Global value chains,large-scale farming,and poverty: Long-term effects in Senegal

This paper presents panel data evidence on the impact of expansion of global value chains and large-scale export-oriented farms in developing countries over almost a decade. We estimate the income effects of wage employment on large-scale farms in the horticultural export sector in Senegal, using data from two survey rounds covering a seven-years period of rapid expansion of the sector. We estimate average income effects as well as heterogeneous income effects, using fixed effects and quantile fixed effects regressions. We find that poverty and inequality reduced much faster in the research area than elsewhere in Senegal. Employment in the horticultural export sector is associated with higher household income and the income effect is strongest for the poorest households. Expansion of the horticultural export sector in Senegal has been particularly pro-poor through creating employment that is accessible and creates substantial income gains for the poorest half of the rural population. These pro-poor employment effects contrast with insights in the literature on increased inequality from rural wage employment.