A high-legume low-glycemic index diet reduces fasting plasma leptin in middle-aged insulin-resistant and -sensitive men.

Fasting leptin and ghrelin levels were measured in 36 insulin-sensitive (IS) and 28 insulin-resistant (IR) men who consumed a legume-enriched low-glycemic index (LG) diet or healthy American (HA) diet in a randomly ordered cross-over feeding study consisting of two 4-week periods. Weight remained stable over the entire study. Fasting plasma leptin was significantly reduced from pre-study levels by both the LG (18.8%, P < 0.001) and HA (16.1%, P < 0.001) diets, whereas fasting ghrelin did not change. By subgroup analysis according to prestudy insulin status, leptin was reduced in IR subjects after both the LG (17.1%, P < 0.01) and the HA (33.3%, P < 0.001) diets, whereas IS subjects responded only after the LG diet (23.1%, P < 0.01). Thus, a legume-rich LG index diet may be a beneficial strategy for reducing circulating leptin concentrations, even under conditions of weight maintenance.

A Structural Modeling Approach to a Multilevel Random Coefficients Model.

A method for estimating the random coefficients model using covariance structure modeling is presented. This method allows one to estimate both fixed and random effects. A way of translating the general linear mixed model into a structural equation modeling (SEM) format is presented. In particular, a LISREL setup for the multiple group linear latent growth curve model is illustrated with suggestions on ways to parameterize more complex models. To illustrate the procedure, we apply the method to both simulated and real data. The method is shown to recover the simulated parameter values. Results and interpretation for the Belsky and Rovine (1990) marriage data are presented. Other applications of the more general model are suggested.

Assessment of neural network models using prediction analysis.

Examination of classification or confusion matrices in neural network models is often advocated as a way to investigate the effects of network architecture on classification rules and to understand the topography of the classification space. In addition, for model comparison purposes it is useful to be able to make statements concerning the statistical reliability of these patterns of hit and error cells. Prediction analysis provides a number of descriptive and inferential measures for the evaluation of hypotheses about patterns of hit and error cells. The present paper applied recent advances in prediction analysis to the examination of neural network classification matrices. Results of the application of prediction analysis to the generalized XOR problem and to data from classification of cardiovascular responses of human subjects were used to illustrate the determination of absolute and relative fit of omnibus models as well as the evaluation of specific hypotheses within these models.

Nonmaternal care in the first year of life and the security of infant-parent attachment.

Evidence from 2 longitudinal studies of infant and family development was combined and examined in order to determine if experience of extensive nonmaternal care in the first year is associated with heightened risk of insecure infant-mother attachment and, in the case of sons, insecure infant-father attachment. Analysis of data obtained during Strange Situation assessments conducted when infants were 12 and 13 months of age revealed that infants exposed to 20 or more hours of care per week displayed more avoidance of mother on reunion and were more likely to be classified as insecurely attached to her than infants with less than 20 hours of care per week. Sons whose mothers were employed on a full-time basis (greater than 35 hours per week) were more likely to be classified as insecure in their attachments to their fathers than all other boys, and, as a result, sons with 20 or more hours of nonmaternal care per week were more likely to be insecurely attached to both parents and less likely to be securely attached to both parents than other boys. A secondary analysis of infants with extensive care experience who did and did not develop insecure attachment relationships with their mothers highlights several conditions under which the risk of insecurity is elevated or reduced. Both sets of findings are considered in terms of other research and the context in which infant day-care is currently experienced in the United States.