Detection of interactions in experiments on large numbers of factors

One of the main advantages of factorial experiments is the information that they can offer on interactions. When there are many factors to be studied, some or all of this information is often sacrificed to keep the size of an experiment economically feasible. Two strategies for group screening are presented for a large number of factors, over two stages of experimentation, with particular emphasis on the detection of interactions. One approach estimates only main effects at the first stage (classical group screening), whereas the other new method (interaction group screening) estimates both main effects and key two-factor interactions at the first stage. Three criteria are used to guide the choice of screening technique, and also the size of the groups of factors for study in the first-stage experiment. The criteria seek to minimize the expected total number of observations in the experiment, the probability that the size of the experiment exceeds a prespecified target and the proportion of active individual factorial effects which are not detected. To implement these criteria, results are derived on the relationship between the grouped and individual factorial effects, and the probability distributions of the numbers of grouped factors whose main effects or interactions are declared active at the first stage. Examples are used to illustrate the methodology, and some issues and open questions for the practical implementation of the results are discussed.     

Predicting distances using a linear model: the case of varietal distinctness

Differences between plant varieties are based on phenotypic observations, which are both space and time consuming. Moreover, the phenotypic data result from the combined effects of genotype and environment. On the contrary, molecular data are easier to obtain and give a direct access to the genotype. In order to save experimental trials and to concentrate efforts on the relevant comparisons between varieties, the relationship between phenotypic and genetic distances is studied. It appears that the classical genetic distances based on molecular data are not appropriate for predicting phenotypic distances. In the linear model framework, we define a new pseudo genetic distance, which is a prediction of the phenotypic one. The distribution of this distance given the pseudo genetic distance is established. Statistical properties of the predicted distance are derived when the parameters of the model are either given or estimated. We finally apply these results to distinguishing between 144 maize lines. This case study is very satisfactory because the use of anonymous molecular markers (RFLP) leads to saving 29% of the trials with an acceptable error risk. These results need to be confirmed on other varieties and species and would certainly be improved by using genes coding for phenotypic traits.     

The Courtship Dance: Patterns of Nonverbal Synchronization in Opposite-Sex Encounters

This study examines the existence of behavioral correlates of synchronization on different levels of analysis and methods. We were unable to demonstrate a relation between synchronization defined in terms of movement echo or position mirroring and subjective experience of pleasure and interest in opposite-sex encounters. Significant results were found for a phenomenon we describe as hierarchically patterned synchronization. These patterns were identified with the help of a newly developed search algorithm. If a female is interested in a male, highly complex patterns of behavior with a constant time structure emerge. The patterns are pair-specific and independent from behavioral content. This rhythmic structure of interactions is discussed in functional terms of human courtship.     

Boundary Politics in the Public Sphere: Openness, Secrecy, and Leak

The issue of openness/secrecy has not received adequate attention in current discussion on the public sphere. Drawing on ideas in critical theory, political sociology, and cultural sociology, this article explores the cultural and political dynamics involved in the public sphere in modern society vis-à-vis the practice of open/secret politics by the state. It argues that the media, due to their publicist quality, are situated at the interface between publicity and secrecy, which thereby allows for struggles over the boundary of state openness/secrecy in the public sphere. A theory of boundary politics is introduced that is contextualized in the relationship among state forms, the means of making power visible/invisible (media strategies), and symbolic as well as discursive practices in the public sphere. In explaining the dynamics of boundary politics over openness/secrecy, three ideal-types of boundary creation are conceptualized: open politics, secrecy, and leak. The theory is illustrated with a case study of the Patten controversy in Hong Kong.     

Periodic review of foster care: a brief national assessment.

A survey of statewide public agencies shows that a majority of states have some form of judicial or administrative periodic review, although few have both. The organizational level of authority and degree of foster care specialization of agencies are positively correlated with administrative review and negatively correlated with judicial review.     

Euler buckling in a wheelbarrow obstacle course: a catastrophe with complex lag

This article studies human physical work capacity under increasing load from a general systems theory perspective. There are several points of generalization between the structure of nonliving (building materials) and living systems (humans) with respect to stress, strain, and fatigue. A catastrophe model for Euler buckling was transposed and tested for human performance in a wheelbarrow obstacle course under varying loads. Subjects were 129 employees of a Midwest manufacturing plant. A cusp model was hypothesized and verified (R2 = .68, control R2 = .11) where vertical load was the asymmetry factor, and body balance, height, and sex-related differences all contributed to bifurcation. A catastrophe model in codimension 10 was also invoked to explain memory in the system. Principal control variables were exercise habits, weight, balance, and sex-related differences (R2 = .75). The core model of human load-to-failure was concluded to be similar to that for Euler buckling: additional complexities were discovered which were attributed in part to systemic memory. Discussion points included the use of large dimension catastrophe models for problems involving complex lag effects, and the transposability of the model to the organizational systemic level.     

It Is Not Just About Location: Infants Perseverate to Container Shape During Object Search

In searching for a toy hidden at a new location, infants will err by searching at the previously correct location. This study investigated the possibility that 8.5‐month‐old infants would perseverate on the basis of other visual features by which covers could be individuated. Infants saw a toy hidden under 1 of 2 distinctly shaped covers. Following successful retrievals from the Shape A cover, infants saw the toy hidden under the Shape B cover. On this B trial, the covers were at locations that had not been baited on the preceding trials, precluding location perseveration. The infants erred by choosing the unbaited Shape A cover more often than control infants presented with 1 type of cover throughout. The findings suggest that infants perseverate to cover shape and are form biases biased toward cover shape even when location information is sufficient to support retrieval.