Where can obesity management policy make the largest impact? Evaluating sub-populations through a microsimulation approach

Background: There is a critical need to focus limited resources on sub-groups of patients with obesity where we expect the largest return on investment. This paper identifies patient sub-groups where an investment may result in larger positive economic and health outcomes.

Methods: The baseline population with obesity was derived from a public survey database and divided into sub-populations defined by demographics and disease status. In 2016, a validated model was used to simulate the incidence of diabetes, absenteeism, and direct medical cost in five care settings. Research findings were derived from the difference in population outcomes with and without weight loss over 15 years. Modeled weight loss scenarios included initial 5% or 12% reduction in body mass index followed by a gradual weight regain. Additional simulations were conducted to show alternative outcomes from different time courses and maintenance scenarios.

Results: Univariate analyses showed that age 45–64, pre-diabetes, female, or obesity class III are independently predictive of larger savings. After considering the correlation between these factors, multivariate analyses projected young females with obesity class I as the optimal sub-group to control obesity-related medical expenditures. In contrast, the population aged 20–35 with obesity class III will yield the best health outcomes. Also, the sub-group aged 45–54 with obesity class I will produce the biggest productivity improvement. Each additional year of weight loss maintained showed increased financial benefits.

Conclusions: This paper studied the heterogeneity between many sub-populations affected by obesity and recommended different priorities for decision-makers in economic, productivity, and health realms.     

资产证券化信用评级:国外模型方法及其借鉴

资产证券化作为金融重大创新之一,信用评级模型化分析的重点是预期损失的预测.本文通过对国外信用评级机构进行资产证券化信用评级所采用的模型方法的综合评述与研究,提出了对中国资产证券化信用评级的借鉴意义.     

县(市)级土地利用总体规划中耕地需求量预测方法及其应用

科学准确地预测耕地需求量,是制定县(市)级土地利用总体规划的基础.文章根据中国南方某县1996-2005年来的耕地变更调查统计数据,分别采用趋势分析法、回归分析法、指数平滑法、GM(1,1)模型法和灰色-马尔柯夫链模型的方法,对该地区耕地总量进行了模拟和预测.不同方法的预测结果表明,基于灰色-马尔柯夫链方法的预测结果更加准确可靠,更有利于土地管理决策者的经济决策行为.在当前耕地利用方式的背景下,灰色-马尔柯夫链模型可以作为县(市)级土地利用总体规划中耕地需求量预测方法的一种好选择.     

Towards multi-system sociotechnical transitions: why simulate

A number of research frameworks have been developed for studying sociotechnical transitions. These are complex phenomena, particularly those involving multi-system interactions. Given these characteristics, the paper discusses the challenges in studying transitions solely through inductive inference methods. It argues that transition research has reached a point where taking the next step should include modelling and simulation as part of the standard methodological exploratory toolkit for studying the intensity, nature and timing of system interaction that lead to transitions and for producing timely and robust policy recommendations.     

The impact of credit constraints on the performance of Chinese agricultural wholesalers

This article evaluates the impact of credit constraints on the performance of Chinese agricultural wholesalers. We estimate a stochastic frontier function using transaction and credit data of agricultural wholesalers from across China to estimate the efficiency and productivity impacts of credit constraints on sales of affected agricultural wholesalers. Empirical results show that micro- and smaller wholesalers are disproportionally impacted by credit constraints and that eliminating these constraints would increase the sales of affected agricultural wholesalers by approximately 15%. Thus, policies aimed at providing credit access for these wholesalers would significantly boost the performance of smaller agricultural wholesalers while improving the overall performance of the Chinese food supply chain without requiring additional non-credit inputs.     

国际贸易对碳减排协议的促进作用——理论框架及减排意愿的数值一般均衡情景模拟

全球碳减排谈判是具有外部性特征的多方合作博弈。文章首先构建一个单一商品无贸易多国模型,对各国的碳减排意愿进行刻画,利用相关数据对不同情景下的各国碳减排意愿进行数值一般均衡模拟;在此基础上,将国际贸易因素引入模型,重新对各国的减排意愿进行情景模拟。数值模拟结果表明:(1)经济规模越大,全球变暖持续的时间跨度越长,温度上升带来的效用损失越大,各国单方面减排意愿越强;(2)国际贸易的存在更有利于各国碳减排意愿的提高,因为各国通过减产实现减排的同时,其贸易条件得到改善,从而将减产带来的效用损失部分转嫁到其他各国;(3)当前,假借碳减排之名而抬头的新贸易保护主义不仅无法促进各国碳减排,反而将阻碍全球碳减排协议的达成。     

A CGE analysis of oil price change

As Chinese economy system has been depended more on the import of petroleum with the development of China, the change in the price of international oil have caused concern among economists and policy makers. This paper is to present a financial Computable General Equilibrium (CGE) model of the Chinese economy which integrates real economy and financial sectors, and to apply it to quantitatively evaluate the impacts on Chinese economy caused by international oil price changes. And the model endogenously determines the exchange rate, covering fixed, partially flexible, and completely flexile exchange rate system to consider the effect of foreign oil price changes from the point of view of macro and industrial aspects. Finally, this paper presents concluding remarks.     

The effectiveness of monetary policy and output fluctuations: An asymmetric analysis

Previous studies have investigated asymmetries in the effects of monetary policy on the real economic activity by using either vector autoregressive (VAR)-based regime-switching models with smooth transition technique or Gaussian functions to parameterise the dynamic effects of structural shocks on the economy. These kinds of VAR models assume asymmetry as a short-run relationship between the series since the long-run neutrality hypothesis of money states that monetary policy can only affect productive capacity of the economy in the short run, but not in the long run. The recent theoretical literature shows that this hypothesis is not quite right. Thus, this paper examines the extent to which monetary policy has a long-run asymmetric effect on output in a number of Organisation for Economic Co-operation and Development countries by using a nonlinear hidden cointegration analysis within a likelihood-based panel framework. The findings indicate that there is a long-run relationship between the real interest rate as an indicator of monetary policy and the growth rate of real output in five countries out of nine under review. This gives support for the view that output has responded asymmetrically to the real interest rate changes. The economic implication of our results is that monetary policy affects positive and negative output fluctuations differently.     

Empirical Evidence of the Leverage Effect in a Stochastic Volatility Model: A Realized Volatility Approach

Increasing attention has been focused on the analysis of the realized volatility, which can be treated as a proxy for the true volatility. In this paper, we study the potential use of the realized volatility as a proxy in a stochastic volatility model estimation. We estimate the leveraged stochastic volatility model using the realized volatility computed from five popular methods across six sampling-frequency transaction data (from 1-min to 60- min) based on the trust region method. Availability of the realized volatility allows us to estimate the model parameters via the MLE and thus avoids computational challenge in the high dimensional integration. Six stock indices are considered in the empirical investigation. We discover some consistent findings and interesting patterns from the empirical results. In general, the significant leverage effect is consistently detected at each sampling frequency and the volatility persistence becomes weaker at the lower sampling frequency.     

主从系统自跟踪调速方案的设计与仿真

设计了一种采用单片机和变频器组成的主从系统自跟踪调速方案．首先通过高精度光栅拾取主动系统的转速信号,由单片机处理后得到转速大小．当主动系统转速变化时,通过变频控制使从动系统的转速做跟随变化．重点说明了该控制方法的基本原理和设计原理,并通过proteus对系统的硬件电路和软件程序进行仿真,表明该控制方法达到设计要求．