Growth characteristics of breast-fed compared to formula-fed infants

In affluent populations, breast-fed infants generally exhibit a different pattern of growth than formula-fed infants. The average weight gain of the former is lower than that of the latter, even after complementary foods are introduced. In some studies, the length gain is also lower among breast-fed infants, whereas in others there is no significant difference in linear growth between feeding groups. Growth in head circumference does not differ by feeding mode. Because of the difference in weight gain, breast-fed infants are generally leaner than formula-fed infants by 12 months of age. Breast-fed infants appear to self-regulate their energy intake at a lower level than consumed by formula-fed infants and have a lower metabolic rate. Evidence to date suggests that there are no apparent adverse consequences associated with the lower intake and slower weight gain of breast-fed infants: compared to formula-fed infants, they do not differ in activity level, and they experience less illness and appear to have enhanced cognitive development. The reasons for differences in growth patterns by feeding mode require further research.     

Post hoc explanation is not prediction. Commentary on J. Archer.

Comments on J. Archer's 1996 article in which he considers whether observed patterns of sex differences in human social behavior are best explained by social role theory or by the evolutionary principles of Darwinian theory. The author believes that Archer framed many of his evolutionary claims as explanations despite the fact that they were generated post hoc. The author argues that a critical weakness of post hoc explanation is that various aspects of a theory may be used selectively to maximize the appearance of predictive validity and an example is used to illustrate the point. It is concluded that while evolutionary psychology is a promising and intriguing field its theories are not adequately tested by post hoc couched in predictive language. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Crash Course for Preparing Students for a First Course in Computing: Did it Work?

To improve the performance of students in a required core course in computing, we added a voluntary “boot camp” crash course in the first week of the semester. The boot camp students did remarkably better in the course. Using collected data from two semesters (252 students of which 73 voluntarily enrolled in boot camp), we used observational study with matched sampling to evaluate the effectiveness of the boot camp. We were able to show, with a high degree of confidence, that the boot camp had a direct benefit on freshman and sophomore students and/or students with a higher than average external load.     

Effect of seed lectins from Phaseolus vulgaris on the development of larvae of Callosobruchus maculatus; mechanism of toxicity

Seeds of the kidney bean (Phaseolus vulgaris) are toxic to developing larvae of the bruchid beetle (Callosobruchus maculatus), a major storage pest of many legumes. Insect feeding trials were carried out whereby the albumin and globulin protein fractions from seeds of P. vulgaris were incorporated into artificial seeds. Both fractions were shown to be toxic and to contain haemagglutinating activity, implicating the seed lectins as being involved in seed resistance. Further feeding trials using different P. vulgaris lectin preparations confirmed the toxicity of these lectins and suggested that it was the E-type lectin subunits (erythrocyte-binding) which were the major antimetabolites. Indirect immunofluorescence investigations using monospecific antisera for globulin lectins showed that the lectins, when ingested by the larvae, bound to the midgut epithelial cells. It was suggested that the mechanism of lectin toxicity in this instance is analogous to that known to occur in the rat, namely that the ingested lectin causes disruption of the epithelial cells of the larval midgut leading to breakdown of the transport of nutrients into these cells, and the absorption of potentially harmful substances. This is the first time that evidence for the mechanism of lectin toxicity has been obtained in insects.     

A generalized Vlasov theory for composite beams

A generalized Vlasov theory for composite beams with arbitrary geometric and material sectional properties is developed based on the variational asymptotic beam sectional analysis. Instead of invoking ad hoc kinematic assumptions, the variational-asymptotic method is used to rigorously split the geometrically-nonlinear, three-dimensional elasticity problem into a linear, two-dimensional, cross-sectional analysis and a nonlinear, one-dimensional, beam analysis. The developed theory is implemented into VABS, a general-purpose, finite-element based beam cross-sectional analysis code. Several problems are studied to compare the present theory with published results and a commercial three-dimensional finite element code. The present work focuses on the issues concerning the use of the Vlasov correction in the context of the accuracy of the resulting beam theory. The systematic comparison with three-dimensional finite element analysis results helps to quantitatively demonstrate both the advantages and limitations of the Vlasov theory.     

Novel developmentally regulated phosphoinositide binding proteins from soybean whose expression bypasses the requirement for an essential phosphatidylinositol transfer protein in yeast

Phosphatidylinositol transfer proteins (PITPs) have been shown to play important roles in regulating a number of signal transduction pathways that couple to vesicle trafficking reactions, phosphoinositide-driven receptor-mediated signaling cascades, and development. While yeast and metazoan PITPs have been analyzed in some detail, plant PITPs remain entirely uncharacterized. We report the identification and characterization of two soybean proteins, Ssh1p and Ssh2p, whose structural genes were recovered on the basis of their abilities to rescue the viability of PITP-deficient Saccharomyces cerevisiae strains. We demonstrate that, while both Ssh1p and Ssh2p share approximately 25% primary sequence identity with yeast PITP, these proteins exhibit biochemical properties that diverge from those of the known PITPs. Ssh1p and Ssh2p represent high-affinity phosphoinositide binding proteins that are distinguished from each other both on the basis of their phospholipid binding specificities and by their substantially non-overlapping patterns of expression in the soybean plant. Finally, we show that Ssh1p is phosphorylated in response to various environmental stress conditions, including hyperosmotic stress. We suggest that Ssh1p may function as one component of a stress response pathway that serves to protect the adult plant from osmotic insult.     

Geometry-defining processors for engineering design and analysis

Critical issues of interactive three-dimensional geometry definition and high-speed parallel computation are addressed in a unified fashion by Geometry-Defining Processors (GDPs). GDPs are microprocessors housed in three-dimensional physical polyhedral packages which can be easily manually assembled or reconfigured to construct approximate scale models of physical objects or domains. An individual GDP communicates with neighboring GDPs in an assembly through optical ports associated with the faces of its package. An assembly of communicating GDPs is able to bothdefine a system geometry and, operating as an optimally connected parallel processor,solve the associated continuum partial differential equations required for design evaluation. Combining simplicity-of-use with efficient computational capabilities, the GDP design system should prove useful in numberous engineering applications.     

The densification of rigid PVC dry blend during fusion

The mechanism of fusion of suspension PVC rigid dry blend in low-shear processing involves the compaction, densification, intergrain fusion, and elongation of the grains. Using a “zero-length” capillary, the entrance pressure loss was measured for dry blend at various stages of fusion. The initial decrease in the entrance pressure loss curve during processing is related to the fusion of the primary particle agglomerates. The consequences of the entrance pressure loss decrease on the rate of melting during extrusion are discussed.     

Residual validity is not meaningful.

Comments on the article by R. J. Sternberg and W. M. Williams (see record 1997-04591-002) regarding the empirical validity of the Graduate Record Examination (GRE) in predicting graduate student performance in psychology. Sternberg and Williams claimed to have studied whether the GRE predicts meaningful success in graduate school, but they did not study GRE predictive validity for students applying to graduate school—they used students already selected for graduate school. Thus, it is argued, what Sternberg and Williams actually studied might be termed the residual validity of GRE scores—the validity remaining after some unknown amount of validity is exhausted in the admissions process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)