A note on estimating regression coefficients with missing data

In this note, we consider the problem of estimating regression coefficients when there are missing observations of some explanatory variables. Following Dagenais (1973), Gourieroux and Monfort (1981), and Conniffe (1983a, 1983b), we assume auxiliary relationships exist among explanatory varibles. Several estimatprs and their interrelationships are discussed. We begin with the model of Gourieroux and

Monfort (1981)     

Assessing Risk‐Based Upper Limits of Melamine Migration from Food Containers

Melamine contamination of food has become a major food safety issue because of incidents of infant disease caused by exposure to this chemical. This study was aimed at establishing a safety limit in Taiwan for the degree of melamine migration from food containers. Health risk assessment was performed for three exposure groups (preschool children, individuals who dine out, and elderly residents of nursing homes). Selected values of tolerable daily intake (TDI) for melamine were used to calculate the reference migration concentration limit (RMCL) or reference specific migration limit (RSML) for melamine food containers. The only existing values of these limits for international standards today are 1.2 mg/L (0.2 mg/dm²) in China and 30 mg/L (5 mg/dm²) in the European Union. The factors used in the calculations included the specific surface area of food containers, daily food consumption rate, body weight, TDI, and the percentile of the population protected at a given migration concentration limit (MCL). The results indicate that children are indeed at higher risk of melamine exposure at toxic levels than are other groups and that the 95th percentile of MCL (specific surface area = 5) for children aged 1–6 years should be the RMCL (0.07 mg/dm²) for protecting the sensitive and general population.     

A property of coefficients of variation for ordered bivariate log-normal variables

This paper considers the maximum and minimum of a pair of log-normal variables with equal mean. It shows that either order statistic has a smaller coefficient of variation than the two original log-normal variables provided the latter are of equal variance. When the variances are unequal, as the variance ratio increases, the minimum (maximum), has a smaller coefficient of variation if the correlation coefficient of the log-normal variables is small (small) and the variances are large (small).     

Home Modifications among Community-Dwelling Older Adults: A Closer Look at Race and Ethnicity

ABSTRACT

This study investigated racial and ethnic differences in home modification use. Data from the 2011 National Health and Aging Trends Study were used (n=6,764). Compared with non-Hispanic Whites, Hispanics were less likely to have a grab bar (odds ratio (OR) = 0.6), bath seat (OR = 0.8), or raised toilet (OR = 0.6). Non-Hispanic Blacks were less likely to have a grab bar (OR = 0.7) or bath seat (OR = 0.7) than non-Hispanic Whites, but more likely to have a raised toilet (OR = 1.3). English proficiency largely explained ethnic differences, while health status partially accounted for racial disparities.     

A Systems Approach to Social Entrepreneurship

Currently, disabilities organizations are increasingly being challenged by the requirement for individualized service, expectations to show personal outcomes, and the need to base their services on evidence-based practices. Social entrepreneurship (SE) is being put forward as an innovative approach for dealing with these challenges. This article presents a systems approach to SE based on a program logic model. This model identifies the input factors (a strong social vision, exploiting opportunities, maximizing resources), throughput strategies (entrepreneurial orientation, critical thinking skills, networking, capacity building), and outcome components (improving people’s lives, community-building, improving society) of SE at the micro, meso, and macro level. Also, the importance of planning for contextual changes as a social entrepreneur is discussed. The article concludes with presenting three inspiring practices regarding SE in the field of disabilities organizations.     

Improvisation – An emergence theory perspective

The paper addresses the occurrence of improvisation and intuition within dynamic business environments from an emergence theory perspective. As argued, the dynamics of the so-called red queen principle forces competition towards the verge of the manageable, making improvised and intuitive action and decision-making not a shortcoming but a necessity in a successful business context. Particularly, the paper discusses how we may interpret the highly rationalistic acts and outcomes of planning and plans in such chaotic and uncertain contexts. We draw upon a longitudinal study of large industrial project deliveries incorporating more than 25 such deliveries.     

瑞典顾客满意度晴雨表

瑞典是世界上第一个在全国范围内测量顾客满意度的国家,建立了瑞典顾客满意度晴雨表(SCSB).SCSB基于瑞典30多个行业100多个企业的顾客年度调查数据对于整个国家经济产出的质量状况进行测量.根据SCSB 在瑞典前3年的发展状况,针对SCSB对瑞典国内各行业的影响结果进行分析,进而得出推论--顾客满意度在供给相同需求各异的行业偏低;在需求和供给相匹配的行业偏高;在高度依赖重复购买的行业偏高;而在垄断行业偏低.     

Author Index

Authors Index

Author Index     

12‐Month‐Old Infants' Perception of Attention Direction in Static Video Images

Twelve‐month‐old infants' ability to perceive gaze direction in static video images was investigated. The images showed a woman who performed attention‐directing actions by looking or pointing toward 1 of 4 objects positioned in front of her (2 on each side). When the model just pointed at the objects, she looked straight ahead, and when she just looked, her hands were hidden below the tabletop. An eye movement system (TOBII) was used to register the gaze of the participants. We found that the infants clearly discriminated the gaze directions to the objects. There was no tendency to mix up the 2 object positions, located 10° apart, on the same side of the model. The infants spent more time looking at the attended objects than the unattended ones and they shifted gaze more often from the face of the model to the attended object than to the unattended objects. Pointing did not significantly increase the infants' tendency to move gaze to the attended object, irrespective of whether the pointing gesture was accompanied by looking or not. In all conditions the infants spent most of the time looking at the model's face. This tendency was especially noticeable in the pointing‐only condition and the condition where the model just looked straight ahead.     

Behind the Numbers: Talking Politics with Foreign-born Chinese Americans

This paper discusses results of in‐depth follow‐up interviews conducted with selected individuals of Chinese descent residing in Los Angeles and San Francisco who were previously chosen at random to participate in the 2000 and 2001 Pilot National Asian American Political Survey. A total of 15 male and female informants who had migrated from Taiwan, mainland China, and Hong Kong were interviewed in Mandarin Chinese. They were asked to compare the performance of the US Government with that of the government in their respective ethnic homeland. They were also asked to explain their reasons for supporting a certain US political party, ideology, and type of candidate. In addition, they commented on the state of political participation or the lack of it among Chinese Americans. Finally, they explained the complexity of their ethnic self‐identification and experiences of racial discrimination. Their responses were interpreted within the context of the historical formation of the Chinese American community as well as the summary results of the mass opinion survey. The results help dispel myths about Chinese Americans being politically indifferent and irrational. They help illuminate the possible relationships among ethnic identity, homeland politics, and political participation in the host land. They also provide exciting insights into improving the survey instrument for a majority immigrant and non‐Anglophone population.