Modeling the impact of supra-structural network nodes: The case of anonymous syringe sharing and HIV among people who inject drugs

Networks are well understood as crucial to the diffusion of HIV among injection drug users (IDUs), but quasi-anonymous risk nodes - such as shooting galleries - resist measurement and incorporation into empirical analyses of disease diffusion. Drawing on network data from 767 IDUs in Bushwick, Brooklyn, we illustrate the use of calibrated agent-based models (CABMs) to account for network structure, injection practices, and quasi-anonymous transmission in shooting galleries. Results confirm the importance of network structure and actor heterogeneity to the magnitude and speed of HIV transmission. Models further demonstrate that quasi-anonymous injections in shooting galleries increase the speed of HIV diffusion across the whole network and have the greatest impact on HIV seroconversion levels for IDUs at the network periphery. Shooting galleries are shown to be transmission hubs that operate independently of traceable structural ties, linking otherwise unconnected network components. CABMs potentially increase understandings of HIV diffusion dynamics by infusing computer simulations with empirical data.     

碳强度目标:演进、理由与实现

碳强度目标是关于未来要达到的温室气体排放强度的国家承诺。研究碳强度目标对于认识和实现中国气候承诺具有重要意义。严格性、约束力和覆盖范围是碳强度目标的关键要素。碳强度目标具有坚实的理论基础和深刻的现实背景,至少具有与温室气体数量目标同等重要的地位。降低碳强度需要降低温室气体的边际弹性或国民生产总值的边际碳强度,需要将国家碳强度目标分解到行业和企业,还要建立碳排放交易制度。     

政府偏好与制度起源:以1950年代后的收容遣送政策为例

尽管学术文献里没有给出政府偏好的恰当定义,但它的确是解释中国制度变迁中的一个重要变量。运用制度学派的有关制度变迁理论,对收容遣送制度起源的历史作出政治学的解释,可以认为,巩固政权以及与此相联系的城市化与工业化的双重压力,都对政府治理城市秩序的偏好产生了重大影响。1950年代以后的收容遣送政策及其实践,为考察政府偏好与制度设计之间的关联提供了生动的素材。     

气候变化政治对海湾国家的影响

海湾地区气候炎热,淡水资源缺乏。长期以来,海湾国家主要依靠能源出口获取大量资金,借此修建海水淡化工厂等各种设施以适应和改善气候环境的影响。近年来,国际社会在应对全球变暖问题的协调合作中,已形成一种处理全球气候变化的政治。气候变化政治要求各国减少能源消耗和降低二氧化碳排放量以缓解全球变暖趋势,从而对海湾国家以能源出口收益来维护生存环境和社会稳定的基本经济模式构成冲击。面对气候变化政治带来的冲击,海湾国家目前的权宜选择只能是继续扩大能源出口,并尽量拖延实施气候变化协议来进行应对。然而,这种做法虽可以暂时保持海湾国家改善环境的努力和维护其经济政治结构稳定,但却难以消除全球气候变化政治今后长期推动能源结构调整和节能减排所带来的压力。     

Supply Chain Strategies and International Tax Arbitrage

What motivates the geographic footprint of the supply chains that multinational firms (MNFs) deploy? Traditional research in the operations and supply chain management literature tends to recommend locations primarily based on differentials in production costs and the ramifications of physical distance ignoring the role of taxation. MNFs that strategically position parts of their supply chains in low‐tax locations can allocate the profits across the divisions to improve post‐tax profits. For the profit allocation to be defensible to tax authorities, the divisional operations must possess real decision authority and bear meaningful risks. Generally speaking, the greater the transfer of risk and control, the larger the allowable allocation of profit. These transfers may also create inefficiencies due to misalignment of business goals and attitudes toward risk. We model these trade‐offs in the context of placing in a low‐tax region a subsidiary that oversees product distribution (as a limited risk distributor commissionnaire, limited risk distributor, or fully fledged distributor). Our analysis demonstrates that the MNF's preferences regarding the operating structures are not necessarily an obvious ordering based on the amount of risk and decision authority transferred to the division in the low‐tax jurisdiction. We derive and analyze threshold values of the performance parameters that describe the main trade‐offs involved in selecting an operating structure. We find some of the optimal decisions to exhibit interesting non‐monotone behavior. For instance, profits can increase when the tax rate in the low‐tax jurisdiction increases. Numerical analysis shows that the Limited‐Risk Distributor structure is rarely optimal and quantifies when each alternative dominates it.     

民事诉讼代理视野下的“草根律师”制度——以成都地区为例

民事诉讼代理制度作为现代民事诉讼制度中的一项重要制度,是法律面前人人平等原则的重要体现和保障。但是在我国农村劳动力向城镇转移、劳动纠纷增多的时代背景下,我国民事诉讼代理制度日益暴露出一系列的问题。课题组通过大量的实证调研,拟从民事诉讼代理制度的基础理论出发,结合我国目前农民工维权的实际,在理论上初步构建“来自于农民工,服务于农民工”的“草根律师”制度,解决有关农民工劳动纠纷案件中的诉讼代理难的相关问题。     

Monotonic change point estimation of generalized linear model-based regression profiles

In this article, a maximum likelihood estimator is derived in the generalized linear model-based regression profiles under monotonic change in Phase II. The performance of the proposed estimator is comprehensively investigated through some special cases, and compared with estimators under step change and drift. The results show that the proposed estimator has better performance in small and medium shifts under different increasing changes. Finally, the applicability of the proposed estimator is illustrated using a real case.     

Likelihood procedure for testing changes in skew normal model with applications to stock returns

The skew normal distribution family is an attractive distribution family due to its mathematical tractability and inclusion of the normal distribution as the special case. It has wide applications in many applied fields such as finance, economics, and medical research. Such a distribution family has been studied extensively since it was introduced by Azzalini in 1985 Azzalini, A. (1985). A class of distributions which includes the normal ones. Scandinavian Journal of Statistics 12:171–178. [Google Scholar] for the first time. Yet, few work has been done on the study of change point problem related to this distribution family. In this article, we propose the likelihood ratio test (LRT) to detect changes in the parameters of the skew normal distribution associated with some asymptotic results of the test statistic. Simulations have been conducted under different scenarios to investigate the performance of the proposed method. Comparisons to some other existing method indicate the comparable power of the method in detecting changes in parameters of the skew normal distribution model. Applications on two real data: Brazilian and Tanzanian stock returns illustrate the detection procedure.     

Competing Values Framework: A useful tool to define the predominant culture in a maternity setting in Australia

Objective

To identify the predominant culture of an organisation which could then assess readiness for change.

Presence and process of fear of birth during pregnancy—Findings from a longitudinal cohort study

Background

The prevalence of fear of birth has been estimated between 8–30%, but there is considerable heterogeneity in research design, definitions, measurement tools used and populations. There are some inconclusive findings about the stability of childbirth fear.