Combining Food Frequency and Survey Data to Quantify Long-Term Dietary Exposure: A Methyl Mercury Case Study

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.     

Chemical and Radiation Environmental Risk Management: Differences, Commonalities, and Challenges

Driven by differing statutory mandates and programmatic separation of regulatory responsibilities between federal, state, and tribal agencies, distinct chemical and radiation risk management strategies have evolved. In the field this separation poses real challenges since many of the major environmental risk management decisions we face today require the evaluation of both types of risks. Over the last decade, federal, state, and tribal agencies have continued to discuss their different approaches and explore areas where their activities could be harmonized. The current framework for managing public exposures to chemical carcinogens has been referred to as a "bottom up approach." Risk between 10(-4) and 10(-6) is established as an upper bound goal. In contrast, a "top down" approach that sets an upper bound dose limit and couples with site specific As Low As Reasonably Achievable Principle (ALARA), is in place to manage individual exposure to radiation. While radiation risk are typically managed on a cumulative basis, exposure to chemicals is generally managed on a chemical-by-chemical, medium-by-medium basis. There are also differences in the nature and size of sites where chemical and radiation contamination is found. Such differences result in divergent management concerns. In spite of these differences, there are several common and practical concerns among radiation and chemical risk managers. They include 1) the issue of cost for site redevelopment and long-term stewardship, 2) public acceptance and involvement, and 3) the need for flexible risk management framework to address the first two issues. This article attempts to synthesize key differences, opportunities for harmonization, and challenges ahead.     

Working Adults and Personal Business Ethics in South East Asia: a Comparative Study in Thailand and Vietnam

Global leaders and managers have been facing new challenges in the twenty-first century since globalization has created a much more integrated and borderless business environment. One of the key issues that they constantly deal with is business ethics. The global economy has made ethical issues become more complex and challenging. Businesses nowadays face urgent demands to act ethically and responsibly. In order for global leaders and managers to manage such a cultural diverse and complex workforce, they must have the ability to understand these complex issues and act ethically. They also need to possess adequate leadership skills to lead an ethical organization in a multinational environment. Thus, understanding and recognizing the cultural differences as well as the ethical standards of people in different countries are critical to the success of global leaders and managers. The purpose of this study is to investigate the perception of working professionals on business ethics in the two high-context cultures in South East Asia: Thailand and Vietnam. Using the Univariate Analysis of Variance method and adopting the widely-used Clark and Clark’s Personal Business Ethics Scores (PBES) measure, this study will compare the level of ethical maturity of the respondents based on a variety of variables including gender, business law course taken, code of conduct, ethics training, and government work experience. The authors will provide a thorough literature review on business ethics as well as the current ethical issues, i.e., bribery and corruption, in the two countries, together with practical suggestions and implications for educators, managers, and employees.     

A linear programming duality approach to analyzing strictly nonblocking <Emphasis Type="Italic">d</Emphasis>-ary multilog networks under general crosstalk constraints

When a switching network topology is used for constructing optical cross-connects, as in the circuit switching case, no two routes are allowed to share a link. However, if two routes share too many switching elements, then crosstalk introduced at those switching elements degrades signal quality. Vaez and Lea (IEEE Trans. Commun. 48:(2)316–323, 2000) introduced a parameter c which is the maximum number of distinct switching elements a route can share with other routes in the network. This is called the general crosstalk constraint. This paper presents a new method of analyzing strictly nonblocking multi-log networks under this general crosstalk constraint using linear programming duality.     

Phylogenetic tree selection by the adjusted k-means approach

The reconstruction of phylogenetic trees is one of the most important and interesting problems of the evolutionary study. There are many methods proposed in the literature for constructing phylogenetic trees. Each approach is based on different criteria and evolutionary models. However, the topologies of trees constructed from different methods may be quite different. The topological errors may be due to unsuitable criterions or evolutionary models. Since there are many tree construction approaches, we are interested in selecting a better tree to fit the true model. In this study, we propose an adjusted k-means approach and a misclassification error score criterion to solve the problem. The simulation study shows this method can select better trees among the potential candidates, which can provide a useful way in phylogenetic tree selection.     

The ensemble Kalman filter is an ABC algorithm

The ensemble Kalman filter is the method of choice for many difficult high-dimensional filtering problems in meteorology, oceanography, hydrology and other fields. In this note we show that a common variant of the ensemble Kalman filter is an approximate Bayesian computation (ABC) algorithm. This is of interest for a number of reasons. First, the ensemble Kalman filter is an example of an ABC algorithm that predates the development of ABC algorithms. Second, the ensemble Kalman filter is used for very high-dimensional problems, whereas ABC methods are normally applied only in very low-dimensional problems. Third, recent state of the art extensions of the ensemble Kalman filter can also be understood within the ABC framework.     

浅论党的十六届六中全会决定的重大意义

十六届六中全会通过的《中共中央关于构建社会主义和谐社会若干重大问题的决定》是一篇马克思主义的重要文献.六中全会的召开和决定的发表标志着邓小平开创的中国特色社会主义的理论与实践又有了新的重大发展;标志着马克思主义关于社会矛盾和社会建设的理论在当代中国得到了全面、直接和生动的体现;标志着执政的中国共产党进入了又一个新的强力作为期.     

Comparison between method of moments and entropy regularization algorithm applied to parameter estimation for mixed-Weibull distribution

Mixed-Weibull distribution has been used to model a wide range of failure data sets, and in many practical situations the number of components in a mixture model is unknown. Thus, the parameter estimation of a mixed-Weibull distribution is considered and the important issue of how to determine the number of components is discussed. Two approaches are proposed to solve this problem. One is the method of moments and the other is a regularization type of fuzzy clustering algorithm. Finally, numerical examples and two real data sets are given to illustrate the features of the proposed approaches.     

Chinese version of the OSI: A validation study

This article examines the construct validity of the Occupational Stress Indicator (OSI) in its Chinese version as well as its criterion-oriented validity against self-reported data on absenteeism and accidents, using a final sample of 1054 workers in the Chinese manufacturing and power industries. The divergent and convergent validities of five of the OSI scales—Job satisfaction, Physical ill-health, Mental ill-health, Type A behaviour and Control—were examined by a multimethod-multitrait matrix technique. Results indicated that the Chinese OSI had fairly good validity in relation to other well-established measures as well as relevant organizational behaviours.     

A primal-dual approximation algorithm for the Asymmetric Prize-Collecting TSP

We present a primal-dual ?log(n)?-approximation algorithm for the version of the asymmetric prize collecting traveling salesman problem, where the objective is to find a directed tour that visits a subset of vertices such that the length of the tour plus the sum of penalties associated with vertices not in the tour is as small as possible. The previous algorithm for the problem (V.H. Nguyen and T.T Nguyen in Int. J. Math. Oper. Res. 4(3):294–301, 2012) which is not combinatorial, is based on the Held-Karp relaxation and heuristic methods such as the Frieze et al.’s heuristic (Frieze et al. in Networks 12:23–39, 1982) or the recent Asadpour et al.’s heuristic for the ATSP (Asadpour et al. in 21st ACM-SIAM symposium on discrete algorithms, 2010). Depending on which of the two heuristics is used, it gives respectively 1+?log(n)? and $3+ 8\frac{\log(n)}{\log(\log(n))}$ as an approximation ratio. Our algorithm achieves an approximation ratio of ?log(n)? which is weaker than $3+ 8\frac{\log(n)}{\log(\log(n))}$ but represents the first combinatorial approximation algorithm for the Asymmetric Prize-Collecting TSP.