Comparison of the Cancer Risk of Methylene Chloride Predicted from Animal Bioassay Data with the Epidemiologic Evidence

Methylene chloride has been shown to be a lung and liver carcinogen in the mouse; yet, the current epidemiologic data show no adverse health effects associated with chronic exposure to this compound. Hearne et al. have compared the results of a large mortality study on occupational exposure to methylene chloride to the human risk predictions based on the rodent bioassay to point out the inconsistency between the animal toxicologic and human epidemiologic data. The maximum number of lung and liver cancers predicted due to methylene chloride exposure based on the rodent bioassay data was 24 compared to 14 deaths from these cancers actually observed in the Hearne et al. epidemiology study. We assess the minimum risk detectable by the human study in order to calculate the upperbound potency of methylene chloride and compare it to the potency derived from the bioassay data. Results from the epidemiology study imply an upperbound potency of 1.5 x 10(-2) per ppm, compared to 1.4 x 10(-2) per ppm calculated using the most conservative analysis of the animal data. We conclude that the negative epidemiology study of Hearne et al. is not sufficiently powerful to show that the risk is inconsistent with the human risk estimated by modeling the rodent bioassay data. Specifically, the doses to which the workers were exposed, the population studied, and the latency period were not adequate to determine that the risks are outside the bounds of the risk estimates predicted by low-dose modeling of the animal data.     

Longitudinal non-euclidean networks: Applying Galileo

This article discusses the theoretical utility of using a non-Euclidean spatial manifold when describing social networks. It proposes that a variant of metric MDS, the Galileo System, can be particularly useful in analyzing social networks and their changes over time, partially because it does not impose Euclidean assumptions on the data. Two sets of longitudinal network data are examined with Galileo. One is the American air traffic network from 1968–1981. The other is ten groups engaged in a computer conference over a 24 month period. In both cases, the results indicate that a Riemannian spatial manifold is required to describe the network structure. Consistent theoretically valid results based upon the non-Euclidean components of spatial manifold are obtained. Further, they could be readily explained by exogenous factors. The implications of these results for network analysis are discussed.     

Social Status Ranking of Occupations in the People's Republic of China,Taiwan, and the United States

College students (1,039) in three different countries ranked 24 occupations according to social status, as they perceived it existing in their respective societies. The selected occupations were first used by Counts in 1925. There was more agreement than disagreement in the rankings, although exceptions were noted and explained by local conditions. If social status is a determining factor in occupational choice, this cross-cultural study may be useful in examining differences and similarities among college students in different parts of the world.     

Cultural values as determinants of executive attitudes on decision making: An empirical evaluation

This article presents an empirical, cross-cultural investigation of executive attitudes on decision making, risk taking, and executive courage. Twenty-nine Arab and 40 American executives participated in this study. Six hypotheses were tested, with the results showing significant differences between managers from the two business cultures. Recommendations and directions for future research are provided.     

Bayesian nonparametric survival analysis for grouped data

A Bayesian nonparametric estimate of the survival distribution is derived under a particular sampling scheme for grouped data that includes the possibility of censoring. The estimate uses the prior information to smooth the data, giving an estimate which is continuous. As special cases survival estimates for life tables are obtained and the estimate of Susarla and Van Ryzin (1976) is derived. As the weight of the prior information tends to zero, the Bayesian estimate reduces to a continuous version of the nonparametric maximum-likelihood estimate. An empirical Bayes modification of the procedure is illustrated on a data set from Cutler and Ederer (1958).     

Public opposition to genetic engineering

Abstract The extent and sources of public opposition to the use of genetic engineering in agricultural production are examined through data from telephone interviews with 220 farmers and 332 nonfarmers living in eight North Carolina counties. A model suggesting that public opposition to genetic engineering is influenced by demographic characteristics mediated by three intervening variables (awareness of genetic engineering, faith in government and industry, and moral objection to genetic engineering) is analyzed. Moral objection is the strongest predictor of opposition. Opposition is also related to lower awareness and less faith in institutions. Women are more likely to oppose genetic engineering than men. Implications of findings are noted.