Tuition fees and social segregation: lessons from a natural experiment at the University of Paris 9-Dauphine

Using a natural experiment, a sharp rise in tuition fees in some of the programmes at the University of Paris 9-Dauphine, we study the impact of tuition fees on students’ pathways, and outcomes. We apply an optimal matching method to the national database of students’ registrations (SISE) to define a typology of pathways. We then use a nonordered multinomial logit model to evaluate the impact of the rise in tuition fees on the types of pathways selected by the university. We show that there is a significant impact on these pathways. The increase in tuition fees reduces geographic and social mobility, thereby accentuating the phenomena of social segregation. Furthermore, contrary to what some of the studies assert, the rise does not appear to encourage greater effort: we find no impact on the graduation success rate.     

高校岗位设置工作中人员流动问题的研究

本文通过对高校岗位设置工作中人员流动原因、类型及存在问题的分析研究,提出建立高校人员内部流动机制,人员退出机制和高校人才环境培育等方面措施,促进高校人力资源的优化配置和满足高校人员自我发展的需求。     

浅谈中央空调循环水系统水处理的重要性和必要性

中央空调循环水处理是通过中央空调的循环水系统来实现的,这样的水处理之所以重要主要是因为没有经处理的水会使管道腐蚀、结垢等,使得设备的使用寿命大大缩短。     

A Graphical Exposition of the Inconsistency of Optimal Monetary Plans

Abstract: The author presents a geometrical framework in which the inability of discretionary policy (consistent policy in the sense of Kydland and Prescott) to be socially optimal is demonstrated. Policy based on a rule results in a higher level of utility. The author extends the model to demonstrate that policy of a Rogoff conservative central banker results in approaching the same equilibrium as that from a monetary rule. Finally, the framework shows that attempts to exploit the Phillips curve result in stagflation.     

Sequential estimation of a location parameter and powers of a scale parameter from delayed observations

The problem of sequentially estimating a location parameter and powers of a scale parameter is considered in the case when the observations become available at random times. Certain classes of sequential estimation procedures are derived under an invariant balanced loss function and with the observation cost determined by a convex function of the stopping time and the number of observations up to that time.     

The Elasticity of Taxable Income: The Case of South Africa

A key tax policy parameter that has received much attention in the international literature, but about which there is substantial uncertainty, is the overall elasticity of taxable income. The size of this parameter is central to the formulation of tax and transfer policy, as well as for the study of the welfare implications of tax decisions. This paper uses a panel of individual tax returns for the period 2009–2013 and the phenomenon of “bracket creep” to construct instrumental variable estimates of the sensitivity of income to changes in tax rates. Estimates suggest that the overall elasticity of taxable income is approximately 0.3, while that of broad income is significantly lower. The overall response is primarily driven by the elastic response of taxable income for high‐income earners, who have an elasticity of closer to 0.4. Using the elasticity estimates within an optimal tax framework, it is determined that the optimal marginal tax rate for the top 10% of income earners is broadly in line with the current income tax schedule. However, results also suggest that there is little scope for raising marginal rates on high‐income earners further without inducing a negative revenue response.     

最优能源强度与我国经济增长

本文通过一个内生增长模型对能源消费与经济增长的关系进行了分析,证实存在使经济增长率最大化的最优能源强度,并且最优能源强度与能源价格反方向变动.在此基础上,估计了近年来我国的最优能源强度,并测算了实际能源强度与最优值的差距.结果表明,近年来我国实际能源强度高于最优值达3万吨标准煤/亿元以上,且有不断上升的趋势.最后提出了在保持最优能源强度的前提下降低能源消耗的政策建议.     

Optimal excess-of-loss reinsurance contract with ambiguity aversion in the principal-agent model

ABSTRACT

We discuss an optimal excess-of-loss reinsurance contract in a continuous-time principal-agent framework where the surplus of the insurer (agent/he) is described by a classical Cramér-Lundberg (C-L) model. In addition to reinsurance, the insurer and the reinsurer (principal/she) are both allowed to invest their surpluses into a financial market containing one risk-free asset (e.g. a short-rate account) and one risky asset (e.g. a market index). In this paper, the insurer and the reinsurer are ambiguity averse and have specific modeling risk aversion preferences for the insurance claims (this relates to the jump term in the stochastic models) and the financial market's risk (this encompasses the models' diffusion term). The reinsurer designs a reinsurance contract that maximizes the exponential utility of her terminal wealth under a worst-case scenario which depends on the retention level of the insurer. By employing the dynamic programming approach, we derive the optimal robust reinsurance contract, and the value functions for the reinsurer and the insurer under this contract. In order to provide a more explicit reinsurance contract and to facilitate our quantitative analysis, we discuss the case when the claims follow an exponential distribution; it is then possible to show explicitly the impact of ambiguity aversion on the optimal reinsurance.     

中国城市公园的标度律特征分析

科学研判城市公园面积与人口规模的关系,有利于 客观认识和指导城市的可持续发展。采用1996—2019年中 国291个地级及以上城市公园面积与人口规模数据,探究二者 之间的标度关系及其标度因子的时空演化规律,进而采用基于 标度律的公园规模修正模型度量各城市公园面积达到预期值的 程度,并对规模修正指标和人均公园面积进行比较分析,得到 如下结果。1)我国公园面积与人口规模整体呈亚线性规模缩 放关系,公园具有显著规模效应,符合城市标度律特征;时间 上呈现亚线性-超线性-亚线性的阶段性波动演变特征,空间 上分异明显：华南接近线性标度关系,华中、东北、华北、西 南呈典型亚线性关系,华东、西北呈亚线性,但标度因子偏离 度较大。2)大城市在人均公园面积排序中相对靠后,在考虑 规模效应后,排名普遍提高,说明规模修正指标能在消除人口 规模影响的基础上,有效衡量不同规模城市公园面积的水平。 标度律视角下的城市公园规模测度能够为城市人口管理和公园 面积发展的决策提供科学指导,为不同规模城市公园建设提供 可借鉴的比较标准,促进公园与人口的协调发展。     

基于价值工程原理的玻化微珠保温混凝土建筑节能保温体系研究

建筑节能保温体系有很多种,既有现行且被广泛使用的有机保温体系EPS、XPS保温板,又有无机保温体系玻化微珠保温砂浆、玻化微珠保温混凝土。选择哪一种保温体系作为墙体保温方案对成功实现我国节能目标是极其重要的。为此本文以上述四种体系为四个方案,运用价值工程原理结合保温节能五项基本指标进行方案比选,通过比选结果得出玻化微珠保温混凝土保温体系为最优方案。