关于10KV与20KV配电网载的比较与建议

随着城市电力负荷密度的增大,增大配电网成为目前城市电网突出的问题。由于配电电压等级的选用涉及面非常广,会影响到其运行、维护、设备选型等,因此在具体实施前,应认真调查、进行全面规划,让技术先进、经济合理的电压配网发挥出其潜在的优势。     

Educational Development in South Sudan: Conscious Design or Spontaneous Order?

Educational development is key to the future prosperity of South Sudan. Officially the situation appears bleak with up to 50 per cent of primary‐aged children out of school, high reported dropout rates and poor attainment. Those involved in the development of education, government departments, international agencies, individuals and communities are each following one of two different approaches as they seek to extend the reach of education. The article suggests that these different approaches arise because those involved hold to either a conscious‐design or a spontaneous‐order model for educational development. The article looks at the recent development of schools in Juba, the capital of South Sudan, in the light of these two theories and finds, despite the rhetoric of the official reports, that most growth is organic and that most recent educational development is emerging spontaneously.     

Testing for structural change in regression quantiles

Most studies in the structural change literature focus solely on the conditional mean, while under various circumstances, structural change in the conditional distribution or in conditional quantiles is of key importance. This paper proposes several tests for structural change in regression quantiles. Two types of statistics are considered, namely, a fluctuation type statistic based on the subgradient and a Wald type statistic, based on comparing parameter estimates obtained from different subsamples. The former requires estimating the model under the null hypothesis, and the latter involves estimation under the alternative hypothesis. The tests proposed can be used to test for structural change occurring in a pre-specified quantile, or across quantiles, which can be viewed as testing for change in the conditional distribution with a linear specification of the conditional quantile function. Both single and multiple structural changes are considered. We derive the limiting distributions under the null hypothesis, and show they are nuisance parameter free and can be easily simulated. A simulation study is conducted to assess the size and power in finite samples.     

Bartlett correction to the likelihood ratio test for MCAR with two‐step monotone sample

Assuming that two‐step monotone missing data is drawn from a multivariate normal population, this paper derives the Bartlett‐type correction to the likelihood ratio test for missing completely at random (MCAR), which plays an important role in the statistical analysis of incomplete datasets. The advantages of our approach are confirmed in Monte Carlo simulations. Our correction drastically improved the accuracy of the type I error in Little's (1988, Journal of the American Statistical Association, 83 , 1198–1202) test for MCAR and performed well even on moderate sample sizes.     

Revisiting the relationship between suicide and unemployment: Evidence from linear and nonlinear cointegration

This study employs the linear and nonlinear ARDL cointegration methodologies to examine the potential symmetric and asymmetric responses of suicide rates to unemployment rates in the US from 1928 to 2013. Our results suggest that suicide rates are pro-cyclical with respect to the business cycle (measured by changes in the unemployment rate) after extensively controlling for divorce and fertility rates. Unemployment has symmetric long-run effects on the age-adjusted suicide rate and four age-specific (from ages 25–34 to 55–64) suicide rates, while the effect of an economic expansion on suicide rates for those aged over 45 is greater than the effect of an economic recession. These findings imply that the effect of an economic expansion on the decrease of the suicide rate is higher than the effect of an economic recession on the increase of the suicide rate for individuals aged over 45. Therefore, intervention designed to reduce suicidal behaviors should emphasize periods of economic recession more than periods of economic expansion for those of middle age and beyond.     

Firm-level determinants of tax evasion in transition economies

Business tax evasion is an important issue for governments. Yet the factors that determine business tax evasion have not been sufficiently examined in the literature in general, and in transition contexts in particular. To address this gap, this study uses the WB/EBRD Business Environment and Enterprise Performance Survey (BEEPS) database with a sample of over 12,692 firms from 26 transition economies. Applying various modelling strategies, we argue that tax evasion is a function of firm-level and institutional-level variables. We contribute to the literature by providing robust evidence showing that the perceived tax burden has a positive impact on tax evasion. We also find that the tax evasive behaviour of firms is positively influenced by low trust in government and in the judicial system as well as by higher perceptions of corruption and higher compliance costs. We find that smaller firms, individual businesses and firms in sectors that are less visible to the tax administration are more likely to get involved in evasive behaviour. Overall, institutional factors play an important role in determining firms’ tax evasion behaviour in transition economies. This finding has important policy implications.     

Programme Evaluation with Unobserved Heterogeneity and Selective Implementation: The Mexican PROGRESA Impact on Child Nutrition

This paper considers the impact of Programa de Educación, Salud y Alimentación ( PROGRESA ), a large Mexican rural anti-poverty programme that had an evaluation sample in which overall treatment was randomly assigned to some communities but not others, on child nutrition. When we examine the impact of PROGRESA based on the presumption of randomized allocations, we find that PROGRESA had no or even a negative impact on child nutrition. However, not all children designated to receive nutritional supplements actually did so. Our preferred estimates – child fixed-effects estimates that control for unobserved heterogeneity that is correlated with access to the supplement – indicate a significantly positive and fairly substantial programme effect of the nutritional supplements on children 12–36 months. They imply an increase of about a sixth in mean growth per year for these children and a lower probability of stunting. Effects are somewhat larger for children from poorer communities but whose mothers are functionally literate. The long-term consequences of these improvements are non-trivial; its impact working through adult height alone could result in a 2.9% increase in lifetime earnings.     

Quality and Welfare in a Mixed Duopoly with Regulated Prices: The Case of a Public and a Private Hospital

Abstract. Hospital markets are often characterized by price regulation and the existence of different ownership types. Using a Hotelling framework, this paper analyses the effect of heterogeneous objectives of hospitals on quality differentiation, profits and overall welfare in a price‐regulated duopoly with exogenous symmetric locations. In contrast to other studies on mixed duopolies, this paper shows that, in this framework, privatization of the public hospital may increase overall welfare. This holds if the public hospital is similar to the private hospital or less efficient and competition is low. The main driving force is the single‐regulated price which induces under‐provision (over‐provision) of quality of the more (less) efficient hospital compared with the first best. However, if the public hospital is sufficiently more efficient and competition is fierce, a mixed duopoly outperforms both a private and a public duopoly due to an equilibrium price below (above) the price of the private (public) duopoly. This medium price discourages over‐provision of quality of the less efficient hospital and – together with the non‐profit objective – encourages an increase in quality of the more efficient public hospital.     

The asymmetry of the New Keynesian Phillips Curve in the euro-area

Using a two-stage quantile regression framework, we uncover significant asymmetries across quantiles for all coefficients in an otherwise standard New Keynesian Phillips Curve (NKPC) for the euro area. A pure NKPC specification accurately captures inflation dynamics at high inflation quantiles.     

Affirmative action in contest games

This paper analyzes the incentive effects of affirmative action in competitive environments. Competition is between heterogeneous players in a contest game where heterogeneity might be due to past discrimination. Two policy options are analyzed that tackle the underlying asymmetry: either it is ignored and the contestants are treated equally, or affirmative action is implemented to neutralize the disadvantages of discriminated players. Comparing the induced effort exertion under the two policies reveals that in a two-player contest game the normative neutralization objective of affirmative action coincides with higher effort exertion. However, in the multi-player contest affirmative action might have adverse incentive effects as the participation of additional weak players detrimentally affects effort incentives of other players. These results also obtain under imperfect information of the contest organizer.