Preventing HIV in injection drug users: exploring the tradeoffs between interventions

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs.     

一种基于非正交信道的分布式中继选择及功率分配方法

针对非正交两跳多中继协作通信系统中的分布式中继选择问题,提出了一种基于非正 交信道的中继选择准则,简化了系统的设计。分析了其误码率性能,给出了其解析表达式 和以总功率为约束条件下的最优功率分配方案。仿真结果表明,最佳中继选择准则明显优于 传统的中继选择准则,且在最优功率分配方案下,可以获得明显的分集增益,系统的误码率 显著下降。     

产品的制造成本——以某中国电子制造厂的产品生产成本核算方法为例

本文记录了一个在中国小型电子制造厂的制造成本分析的案例,文章先对比了传统产品成本分析和作业成本分析法,以及动态和静态成本分析的方法,然后展示了成本分析项目的步骤以及做出的一些成本分摊的决定并且阐述了这些决定后面的理由。     

“环保费改税”提高了重污染企业全要素生产率吗？

《环境保护税法》的实施为检验“环保费改税”的效果提供了准自然实验。以2015—2020年沪深A股重污染行业上市公司为样本,采用双重差分模型（DID）检验了“环保费改税”对重污染企业全要素生产率的影响。研究结果表明：“环保费改税”显著提高了税费负担提标地区重污染企业的全要素生产率,整体上支持了“波特假说”;但是,税费负担提标地区重污染企业全要素生产率的提高并非源于“环保费改税”引发的创新补偿效应,而是源于“环保费改税”增加了资源配置效率。上述结果支持了“波特假说”有关“环境规制优化了资源配置效率进而提高企业生产率”的结论。进一步分析发现,“环保费改税”对税费负担提标地区重污染企业全要素生产率的提升效应在民营企业和研发投入强度大的企业中更显著。     

Does bond market development enhance the banking sector’s efficiency in resource allocation? Industry-level evidence from Korea

Korea’s financial system used to be bank-based, with banks playing the leading role in financing corporations. As highlighted by Park et al. (2019), however, bond markets have developed rapidly in Korea and other Asian countries. The corporate bond market competes with banks as a source of finance for large borrowers. As such, bond markets may affect banking sector operation, a process known as disintermediation. In this paper, we examine whether bond market development improves the efficiency of resource allocation in Korean bank lending. We propose two channels through which bond market development affects the efficiency of bank lending. Since the two channels have opposing effects on the efficiency of banking, the issue must be settled by empirical analysis. We find that bank loans are much less efficient than bond financing in allocating resources across industries. Furthermore, banks are particularly inefficient in resource allocation in industries that rely more on bond financing. This suggests that competition from bond financing does not improve allocative efficiency of bank loans.     

Sharing a River

A group of agents located along a river have quasi-linear preferences over water and money. We ask how the water should be allocated and what money transfers should be performed. The core lower bounds require that no coalition should get less than the welfare it could achieve by using the water it controls. The aspiration upper bounds demand that no coalition enjoy a welfare higher than what it could achieve in the absence of the remaining agents. Exactly one welfare distribution satisfies the core lower bounds and the aspiration upper bounds: it is the marginal contribution vector corresponding to the ordering of the agents along the river. Journal of Economic Literature Classification Numbers: D62, C71.     

技术创新、金融创新与经济增长——基于中国省际面板数据

本文从实证分析层面对金融创新、技术创新与经济增长之间的作用关系进行探讨。基于我国 2000~2015 年省级面板数据,采用GMM估计方法,利用动态面板模型进行实证检验。结果表明：技术创新对经济增长的影响显著为正,单独的金融创新对经济增长起抑制作用,二者的交互作用则对经济增长起显著性正向作用。脱离实体经济的金融创新将抑制经济增长,也会间接阻碍技术创新对经济增长的影响。本文结合当前经济形势,从金融机构与创新企业相接轨共同提高创新水平、培养创新型人才等角度提出建议。     

资源约束与地区经济收敛——基于资源稀缺性与资源配置力的考察

本文从资源稀缺性出发,提出并运用资源配置力这一新的分析工具,对2003年以来中国所面临的经济增长、资源约束与区域经济变动状况作了分析。结果表明,市场供求关系变化导致资源稀缺的结构性变迁与地域性转移,使地区资源配置力与经济竞争力发展相应变动。东部沿海能源与矿产等资源短缺地区备受资源约束递增的压力;中西部尤其是能源与矿产等资源富集地区资源配置力与经济竞争力明显递增,从而出现地区经济收敛趋势。     

Labor Income Taxation,Human Capital,and Growth: The Role of Childcare*

In this paper, we examine the effects of labor income taxation on growth in an overlapping generations model in which schooling and childcare play a role in the production of human capital. We compare such effects with those obtained in a model in which only schooling matters for skill formation. We show that the omission of childcare from the technology of skill formation can bias the results related to the impact of labor income taxation on growth.     

Cost monotonicity, consistency and minimum cost spanning tree games

We propose a new cost allocation rule for minimum cost spanning tree games. The new rule is a core selection and also satisfies cost monotonicity. We also give characterisation theorems for the new rule as well as the much-studied Bird allocation. We show that the principal difference between these two rules is in terms of their consistency properties.