Consumption and Saving Behavior of Older and Younger Baby Boomers in Korea

The 1998 Korean Survey of Family Income and Expenditures was used to examine the overall consumption and saving behavior of Korean baby boomers and compared the differences in consumption and saving behavior between older and younger boomers. The t -test results indicated that the younger boomers allocated a significantly higher percentage of their expenditures on food away from home, household appliances, transportation and communication than did the older boomers, whereas the older boomers spent higher amounts and allocated larger budget shares on their children's education than did the younger boomers. The results of Ordinary Least-Squares (OLS) regression analysis showed that, holding other factors constant, older boomers not only spent significantly more in the total consumption expenditures and education expenditures, but older boomers also saved significantly less than did younger boomers.     

A note on measures of similarity based on centrality

This note presents a measure of similarity between connected nodes in terms of centrality based on Euclidean distances, and compares it to ‘assortative mixing’ [Newman, M.E.J., 2002. Assortative mixing in networks. Physical Review Letters 89, 208701], which is based on Pearson correlation coefficient. This study suggests that the measure based on Euclidean distances may be more appropriate for relatively smaller (N < 500) and denser networks.     

A Diversity Index for Model Space Selection in the Estimation of Benchmark and Infectious Doses via Model Averaging

In chemical and microbial risk assessments, risk assessors fit dose‐response models to high‐dose data and extrapolate downward to risk levels in the range of 1–10%. Although multiple dose‐response models may be able to fit the data adequately in the experimental range, the estimated effective dose (ED) corresponding to an extremely small risk can be substantially different from model to model. In this respect, model averaging (MA) provides more robustness than a single dose‐response model in the point and interval estimation of an ED. In MA, accounting for both data uncertainty and model uncertainty is crucial, but addressing model uncertainty is not achieved simply by increasing the number of models in a model space. A plausible set of models for MA can be characterized by goodness of fit and diversity surrounding the truth. We propose a diversity index (DI) to balance between these two characteristics in model space selection. It addresses a collective property of a model space rather than individual performance of each model. Tuning parameters in the DI control the size of the model space for MA.     

Internationalization and Performance of Firms in China: Moderating Effects of Governance Structure and the Degree of Centralized Control

This study proposes necessary modifications to the existing internationalization–performance relationship to meet the idiosyncrasies of China-specific contexts. We first hypothesize an S-shaped internationalization–performance relationship as the baseline and then investigate the moderating effects of a firm's governance structure and the degree of centralized government control on the relationship between its internationalization and performance. The results, based on a longitudinal sample of manufacturing firms in China for the 2001–2007 period, indicate that (1) the S-shaped internationalization–performance relationship holds for firms in China; (2) the governance structure moderates the internationalization–performance relationship such that increased profitability through internationalization is more likely for modernized firms than for their conventional local counterparts; and (3) the degree of centralized control moderates the internationalization–performance relationship such that increased profitability through internationalization is more likely for firms affiliated with higher level governments than for those affiliated with lower-level governments.     

Temporal Disaggregation: Methods,Information Loss,and Diagnostics

This research provides a generalized framework to disaggregate lower-frequency time series and evaluate the disaggregation performance. The proposed framework combines two models in separate stages: a linear regression model to exploit related independent variables in the first stage and a state–space model to disaggregate the residual from the regression in the second stage. For the purpose of providing a set of practical criteria for assessing the disaggregation performance, we measure the information loss that occurs during temporal aggregation while examining what effects take place when aggregating data. To validate the proposed framework, we implement Monte Carlo simulations and provide two empirical studies. Supplementary materials for this article are available online.     

散热器安装模式对采暖效果的影响

为了探究冷凝壁挂炉散热器的安装模式对采暖效果的影响,建立了散热器对流采暖的数学模型,利用CFD软件 SC/Tetra,采用湍流模型和稳态分析法,模拟了在实际工况下,不同安装模式的散热器达到稳态时温度场和速度场的分 布,并对数值模拟结果进行分析。结果表明：总功率相同的条件下,双散热器相比单个散热器,温度场和速度场更加均匀 平稳,舒适性较好;同侧安装方式比对称安装及对角线方向安装方式也更具有优越性,该研究为今后的工程应用提供理 论依据。     

An Empirical Examination of Characteristics of Mexican Migrants to Metropolitan and Nonmetropolitan Areas of the United States*

Abstract This research examines differences between those Mexican migrants choosing metropolitan destinations and those choosing destinations outside metropolitan areas of the United States. Using general estimating equations, the study presents data indicating that since the 1960s migrants choosing rural destinations are less fluent in English, slightly older, much less educated, far more likely to be unskilled, more likely to be married, and more likely to be undocumented. The picture is more complex when consideration is restricted to those migrants arriving in rural areas since the passage of the North American Free Trade Agreement. These migrants are far more likely to be single, have more education but have less English fluency, have less work experience, and have less family experience with migration to the United States. They are more likely to come from small towns and rural areas of Mexico.     

Subtyping Non-treatment-seeking Problem Gamblers Using the Pathways Model

This study examined whether distinct subgroups could be identified among a sample of non-treatment-seeking problem and pathological/disordered gamblers (PG) using Blaszczynski and Nower’s (Addiction 97:487–499, 2002) pathways model (N = 150, 50% female). We examined coping motives for gambling, childhood trauma, boredom proneness, risk-taking, impulsivity, attention-deficit/hyperactivity disorder (ADHD), and antisocial personality disorder as defining variables in a hierarchical cluster analysis to identify subgroups. Subgroup differences in gambling, psychiatric, and demographic variables were also assessed to establish concurrent validity. Consistent with the pathways model, our analyses identified three gambling subgroups: (1) behaviorally conditioned (BC), (2) emotionally vulnerable (EV), and (3) antisocial-impulsivist (AI) gamblers. BC gamblers (n = 47) reported the lowest levels of lifetime depression, anxiety, gambling severity, and interest in problem gambling treatment. EV gamblers (n = 53) reported the highest levels of childhood trauma, motivation to gamble to cope with negative emotions, gambling-related suicidal ideation, and family history of gambling problems. AI gamblers (n = 50) reported the highest levels of antisocial personality disorder and ADHD symptoms, as well as higher rates of impulsivity and risk-taking than EV gamblers. The findings provide evidence for the validity of the pathways model as a framework for conceptualizing PG subtypes in a non-treatment-seeking sample, and underscore the importance of tailoring treatment approaches to meet the respective clinical needs of these subtypes.