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G Fitzmaurice

Publications and source records attributed to G Fitzmaurice.

11 recordsLinked to original sources
PubMed2001

How to explain an interaction.

In this column, I have considered some simple tabular and graphical techniques that are helpful in explaining the substantive meaning of an interaction. When both of the explanatory variables are discrete, these techniques are easy to apply and provide both qualitative and quantitative interpretations of the interaction. As noted earlier, the more challenging case is one in which one or more of the explanatory variables are quantitative. One simple proposal is to construct two "reference levels" for each of the quantitative explanatory variables Then, given this set of reference levels, the explanation of the interaction can proceed along the same lines as for the case in which both explanatory variables are discrete. However, some care must be taken in the choice of reference levels.

Education↗
PubMed2001

The transcription factor early growth-response factor 1 modulates tumor necrosis factor-alpha, immunoglobulin E, and airway responsiveness in mice.

Early growth-response factor 1 (Egr-1) is a sequence-specific transcription factor that plays a regulatory role in the expression of many genes important in inflammation, cell growth, apoptosis, and the pathogenesis of disease. In vitro studies suggest that Egr-1 is capable of regulating the expression of tumor necrosis factor-alpha (TNF-alpha) and other genes involved in airway inflammation and reactivity following allergen stimulation. On the basis of these data, we hypothesized that in the absence of Egr-1, the TNF-alpha response and subsequent downstream inflammatory events that usually follow allergen challenge would be diminished. To test our hypothesis Egr-1 knock-out (KO) mice were examined in an ovalbumin (OVA)-induced model of airway inflammation and reactivity, and compared with identically treated wild-type (WT) control mice. In response to OVA sensitization and airway challenge, KO mice had diminished TNF-alpha mRNA and protein in the lungs and mast cells compared with WT mice. Interestingly, the KO mice had elevated IgE levels at baseline and after allergen challenge compared with WT mice. Furthermore, the airways of KO mice were hyporesponsive to methacholine challenge at baseline and after allergen challenge. These data indicate that Egr-1 modulates TNF-alpha, IgE, and airway responsiveness in mice.

Animals↗
PubMed1999

Meta-analysis.

Explore the source record for details and available documents.

Cardiovascular Diseases↗
PubMed1994

An extension of Yule's Q to multivariate binary data.

In this note we describe a summary measure of pairwise association for multivariate binary data based on the conditional odds ratio. The proposed measure is an extension of Yule's Q to more than two binary random variables. Unlike marginal measures of association, this measure is not constrained by the marginal probabilities of success. For example, when each binary variable has a different probability of success, the upper limit of the pairwise marginal correlation coefficient is constrained to be less than 1. If one prefers a measure of association that is unconstrained, then with only two binary variables, Bishop, Feinberg, and Holland (1975, Discrete Multivariate Analysis: Theory and Practice, Cambridge, Massachusetts: MIT Press) suggest the use of the odds ratio or, equivalently, Yule's Q. Yule's Q transforms the odds ratio between the two binary variables from [0, infinity) to [-1, 1]. We propose an extension of Yule's Q to more than two binary random variables. This measure of pairwise association is based on the conditional odds ratio from a log-linear model.

Animals↗
PubMed1990

Transition to motherhood and the self: measurement, stability, and change.

Different ways of conceptualizing and measuring change in attitudes during transition to motherhood are examined. A series of analyses was performed on data from a cross-sectional sample (N = 667) and a smaller longitudinal sample (n = 48) to demonstrate sound psychometric properties for 2 new scales and to show construct comparability across different phases of childbearing. For Childbearing Attitudes Questionnaire, results demonstrated equality of covariance for 16 scales and comparability of structure and meaning of 4 higher order factors--identification with motherhood, social orientation, self-confidence, and negative aspects of giving birth. For Mothering Self-Definition Questionnaire, results demonstrated equality of covariance of 5 scales and comparability of structure and meaning of a single higher order factor, interpreted as reflecting positive feelings about one's mothering characteristics. Analyses of correlations and mean differences identified areas of change and stability.

Adult↗