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.     

Income and Financial Satisfaction among Older Adults in the United States

Using data from the General Social Surveys,this study compares the effects of differentincome variables on financial satisfactionamong people age 65 and above in the UnitedStates. Results suggest that simply usinghousehold income as a variable without anyadjustment does not capture the real effect ofincome on financial satisfaction. Incomeequivalence scales and per-capita income arebetter income predictors of financialsatisfaction than family income. Given thefact that it is not uncommon in financialsatisfaction as well as subjective well-beingresearch to use the family income variablewithout adjustment, findings regarding theeffect of income from those studies should beinterpreted with caution.     

中韩日三国未来在经济上的竞争与合作

一、导言(一)改变中的世界经济数千年前,古代中国在比较厚实的基础之上,就已发展出灿烂的文化,而这先进的文化与经济也通过“丝绸之路”向西方传播。     

A simulation study of five biased estimators for straight line regression

Five biased estimators of the slope in straight line regression are considered. For each, the estimate of the “bias parameter”, k, is a function of N, the number of observations, and [rcirc]² , the square of the least squares estimate of the standardized slope, β. The estimators include that of Farebrother, the ridge estimator of Hoerl, Kennard, and Baldwin, Vinod's shrunken estimators., and a new modification of one of the latter. Properties of the estimators are studied for 13 combinations of N and 3. Results of simulation experiments provide empirical evidence concerning the values of means and variances of the biased estimators of the slope and estimates of the “bias parameter”, the mean square errors of the estimators, and the frequency of improvement relative to least squares. Adjustments to degrees of freedom in the biased regression analysis of variance table are also considered. An extension of the new modification to the case of p> 1 independent variables is presented in an Appendix.     

Quantile residual life regression based on semi-competing risks data

This paper investigates the quantile residual life regression based on semi-competing risk data. Because the terminal event time dependently censors the non-terminal event time, the inference on the non-terminal event time is not available without extra assumption. Therefore, we assume that the non-terminal event time and the terminal event time follow an Archimedean copula. Then, we apply the inverse probability weight technique to construct an estimating equation of quantile residual life regression coefficients. But, the estimating equation may not be continuous in coefficients. Thus, we apply the generalized solution approach to overcome this problem. Since the variance estimation of the proposed estimator is difficult to obtain, we use the bootstrap resampling method to estimate it. From simulations, it shows the performance of the proposed method is well. Finally, we analyze the Bone Marrow Transplant data for illustrations.     

A probabilistic transmission and population dynamic model to assess tuberculosis infection risk

The purpose of this study was to examine tuberculosis (TB) population dynamics and to assess potential infection risk in Taiwan. A well‐established mathematical model of TB transmission built on previous models was adopted to study the potential impact of TB transmission. A probabilistic risk model was also developed to estimate site‐specific risks of developing disease soon after recent primary infection, exogenous reinfection, or through endogenous reactivation (latently infected TB) among Taiwan regions. Here, we showed that the proportion of endogenous reactivation (53–67%) was larger than that of exogenous reinfection (32–47%). Our simulations showed that as epidemic reaches a steady state, age distribution of cases would finally shift toward older age groups dominated by latently infected TB cases as a result of endogenous reactivation. A comparison of age‐weighted TB incidence data with our model simulation output with 95% credible intervals revealed that the predictions were in an apparent agreement with observed data. The median value of overall basic reproduction number (R₀) in eastern Taiwan ranged from 1.65 to 1.72, whereas northern Taiwan had the lowest R₀ estimate of 1.50. We found that total TB incidences in eastern Taiwan had 25–27% probabilities of total proportion of infected population exceeding 90%, whereas there were 36–66% probabilities having exceeded 20% of total proportion of infected population attributed to latently infected TB. We suggested that our Taiwan‐based analysis can be extended to the context of developing countries, where TB remains a substantial cause of elderly morbidity and mortality.     

A linear-time algorithm for weighted paired-domination on block graphs

Journal of Combinatorial Optimization - In a graph $$G = (V,E)$$ , a set $$S\subseteq V(G)$$ is said to be a dominating set of G if every vertex not in S is adjacent to a vertex in S. Let G[S]...     

Robust mixture modeling using the skew <Emphasis Type="Italic">t</Emphasis> distribution

A finite mixture model using the Student's t distribution has been recognized as a robust extension of normal mixtures. Recently, a mixture of skew normal distributions has been found to be effective in the treatment of heterogeneous data involving asymmetric behaviors across subclasses. In this article, we propose a robust mixture framework based on the skew t distribution to efficiently deal with heavy-tailedness, extra skewness and multimodality in a wide range of settings. Statistical mixture modeling based on normal, Student's t and skew normal distributions can be viewed as special cases of the skew t mixture model. We present analytically simple EM-type algorithms for iteratively computing maximum likelihood estimates. The proposed methodology is illustrated by analyzing a real data example.     

The relationship among interactive justice,leader–member exchange,and workplace friendship

Workplace friendship is an important issue in business. Despite its predominance within the management field, there are several unaddressed issues. This study examines the relationship among interactive justice, leader–member exchange, and workplace friendship. Based on data collected from 309 full-time Taiwanese employees, results indicate that interactive justice is positively associated with workplace friendship. Leader–member exchange mediates such relationships. Therefore, as far as the manager is concerned, interactive justice is an effective factor for promoting workplace friendship and the mediating effect of leader–member exchange cannot be neglected.     

Throwing the Baby Out with the Bathwater: Evaluation of Domain Importance Weighting in Quality of Life Measurements

This paper examined major inconsistencies between claims made and the evidence presented in recent studies on evaluating the role of domain importance weighting in quality of life (QoL) measures. Three inconsistencies were discussed and they were: (1) treating the failure to support a particular importance weighting function as the evidence of uncovering no importance weighting necessary at all, (2) considering domain importance weighting and multiplicative scores synonymous, and (3) extending findings with a within-domain focus to an across-domain focus. Overlooking these inconsistencies may lead to an overgeneralization of study findings, which would likely result in premature or even erroneous conclusions. Caution must be given in interpreting study results in order to avoid overgeneralization which limits our understanding of the true role that domain importance weighting may play in QoL measures.