Contrasting the Impacts of Combat and Humanitarian Assistance/Disaster Relief Missions on the Mental Health of Military Service Members

Abstract

We study the differential impacts of combat and humanitarian assistance/disaster relief (HA/DR) missions on the mental health of U.S. Marine Corps members. The deployment experiences of any individual Marine are plausibly random conditional on the observable characteristics which are used to assign Marines into units. Leveraging this exogenous variation, we compare the incidence of post-traumatic stress disorder (PTSD) and suicide deaths among Marines who deployed to either Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) or HA/DR missions between 2001 and 2011. We find that the hazard of PTSD is close to eight times higher among Marines returning from OEF/OIF compared to those never deployed, and just 1.33 times higher among those returning from HA/DR (and never participated in OEF/OIF). Those returning from OEF/OIF missions are 1.81 times more likely than those never deployed to die by suicide when they were still active duty, and the hazard increases to almost 3 after they have left the military. In contrast, we find no difference in the hazards of suicide death between those that deployed to only HA/DR missions and non-deployed Marines.     

以两个建设"紧密结合"为着力点加强党的先进性建设

胡总书记提出的两个建设“紧密结合”的思想,明确了新世纪加强党的建设的核心内容,是先进性建设的着力点所在。党的执政能力建设与先进性建设具有内在逻辑联系,必须充分认清两个建设“紧密结合”的重要性;两个建设“紧密结合”关系党的建设全局,必须将两个建设统一于党的建设新的伟大工程;党的执政实践是检验先进性的重要标准,必须在执政实践中加强党的先进性建设。     

A two‐echelon inventory‐location problem with service considerations

We study the problem of designing a two‐echelon spare parts inventory system consisting of a central plant and a number of service centers each serving a set of customers with stochastic demand. Processing and storage capacities at both levels of facilities are limited. The manufacturing process is modeled as a queuing system at the plant. The goal is to optimize the base‐stock levels at both echelons, the location of service centers, and the allocation of customers to centers simultaneously, subject to service constraints. A mixed integer nonlinear programming model (MINLP) is formulated to minimize the total expected cost of the system. The problem is NP‐hard and a Lagrangian heuristic is proposed. We present computational results and discuss the trade‐off between cost and service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

Approximation algorithms for general one‐warehouse multi‐retailer systems

Logistical planning problems are complicated in practice because planners have to deal with the challenges of demand planning and supply replenishment, while taking into account the issues of (i) inventory perishability and storage charges, (ii) management of backlog and/or lost sales, and (iii) cost saving opportunities due to economies of scale in order replenishment and transportation. It is therefore not surprising that many logistical planning problems are computationally difficult, and finding a good solution to these problems necessitates the development of many ad hoc algorithmic procedures to address various features of the planning problems. In this article, we identify simple conditions and structural properties associated with these logistical planning problems in which the warehouse is managed as a cross‐docking facility. Despite the nonlinear cost structures in the problems, we show that a solution that is within ε‐optimality can be obtained by solving a related piece‐wise linear concave cost multi‐commodity network flow problem. An immediate consequence of this result is that certain classes of logistical planning problems can be approximated by a factor of (1 + ε) in polynomial time. This significantly improves upon the results found in literature for these classes of problems. We also show that the piece‐wise linear concave cost network flow problem can be approximated to within a logarithmic factor via a large scale linear programming relaxation. We use polymatroidal constraints to capture the piece‐wise concavity feature of the cost functions. This gives rise to a unified and generic LP‐based approach for a large class of complicated logistical planning problems. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

A hybrid method for simulation factor screening

Factor screening is performed to eliminate unimportant factors so that the remaining important factors can be more thoroughly studied in later experiments. Controlled sequential bifurcation (CSB) and controlled sequential factorial design (CSFD) are two new screening methods for discrete‐event simulations. Both methods use hypothesis testing procedures to control the Type I Error and power of the screening results. The scenarios for which each method is most efficient are complementary. This study proposes a two‐stage hybrid approach that combines CSFD and an improved CSB called CSB‐X. In Phase 1, a prescreening procedure will estimate each effect and determine whether CSB‐X or CSFD will be used for further screening. In Phase 2, CSB‐X and CSFD are performed separately based on the assignment of Phase 1. The new method usually has the same error control as CSB‐X and CSFD. The efficiency, on the other hand, is usually much better than either component method. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

A supply chain design model with unreliable supply

Uncertainties abound within a supply chain and have big impacts on its performance. We propose an integrated model for a three‐tiered supply chain network with one supplier, one or more facilities and retailers. This model takes into consideration the unreliable aspects of a supply chain. The properties of the optimal solution to the model are analyzed to reveal the impacts of supply uncertainty on supply chain design decisions. We also propose a general solution algorithm for this model. Computational experience is presented and discussed. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

党对军队绝对领导的根本组织保证——我军党委制的历史考察及其启示

军队的领导权问题,是马克思主义建军理论和实践的核心问题。我军作为党绝对领导下的人民军队,在80年发展历程中,逐渐形成了听党指挥这一最大优势。其根本的组织保证就在于党委制的设立。对此进行认真的回顾与考察,对于新世纪新阶段坚持和完善党委制,坚持党对军队的绝对领导,更好地履行我军的职能使命,有着十分重要的意义。     

Nuclear deterrence in the 21st century

The purpose behind this section is to encourage, and sometimes solicit, short commentary and/or comment on timely topics that play a role in shaping current national and international defense and security policies. There is no limit or constraint on what defense and security topics are chosen, so long as they are timely and have policy relevance. By way of guidance, the nearest equivalent would be feature articles in the more reputable broadsheet press.     

夜间通风量对相变轻质房间室内热环境的影响

运用EnergyPlus软件,对含相变材料层轻质房间的室内热环境进行了模拟,分析了墙体结构、通风量等因素对相变材料轻质墙体的蓄、放热性能和室内热环境的影响。模拟结果表明:相变材料应用于轻质房间,能显著增强围护结构的热惰性,提高室内的热舒适性;同时采取夜间通风技术,可以有效地将白天蓄积的热量散至室外。相变材料布置在围护结构内侧时,室内环境的热舒适性比布置在外侧时更好。从自然通风的角度,相变材料布置于围护结构内侧时,选取换气数2.5次/h作为优化结果;相变材料布置于围护结构外侧时,选取换气数4.0次/h作为优化结果。     

一种基于核心数据区监视的交叉验证方法

通常商用体系结构模拟器不开源,仿真过程中无法直接获取中间结果.提出了一种基于核心数据区监视的交叉验证方法,可将体系结构模拟器运行过程中核心数据区的变化情况提取出来,用以支持该模拟器与寄存器传输级代码的模拟结果进行交叉比对,快速精确定位两者的执行差异,提高验证人员的查错效率.实验分析和实际应用表明,本方法比传统方法可将查...