Applications of in situ magnetic resonance techniques in chemical reaction engineering

NMR spectroscopy is now a well‐established technique for the in situ study of surface chemistry and the chemical processes occurring during catalytic reactions. Developments in probe design are making the sample environments ever closer to the operating conditions of the catalyst in industrial use. In parallel with these advances there is an increasing interest in the application of field gradient magnetic resonance techniques, namely pulsed gradient spin echo (PGSE) NMR and magnetic resonance imaging (MRI), to in situ studies of mass transport processes in catalysts and reactors. An overview of the recent developments in in situ NMR spectroscopy, PGSE NMR and MRI studies in application to catalysis and reaction engineering is presented and the potential of these techniques in the numerical modelling of catalytic processes and reactor design is highlighted. This revised version was published online in August 2006 with corrections to the Cover Date.     

Traits as goal-based categories: The importance of goals in the coherence of dispositional categories.

It is argued that goals are central to the meaning and structure of many traits and help define the prototypicality structure of those traits. Partly on the basis of L. W. Barsalou's (1985) work on goal-derived categories, it was predicted that goals help define the judged prototypicality of many trait-related behaviors and the confidence with which people make trait inferences from those behaviors. Consistent with this hypothesis, ratings of the extent to which behaviors achieved the goal associated with a trait strongly predicted the typicality of the behaviors. Furthermore, the rated goal-relatedness of a behavior also strongly predicted the confidence with which people would make a trait inference from that behavior. It is suggested that goals play a major role in the conceptual coherence of traits and other social categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Childrearing and impulse control in toddlers: A naturalistic investigation.

Observed 18 firstborn toddlers (aged 12–15 mo) and their mothers in their homes on 2 occasions (1 wk apart) for 45 min on each day. Childrearing practices were assessed through interviews and naturalistic observations; impulse control, defined as the nonmanipulation of breakable or dangerous objects, was assessed by describing the objects that infants manipulated. Findings reveal that mothers made numerous demands on their infants for impulse control and enforced them promptly and consistently. Mothers who relied on physical punishment had infants who were more likely to ignore maternal prohibitions, to manipulate breakable objects, and to show low levels of nonverbal competence 7 mo later. Physically punishing mothers made the fewest objects available in their homes for infant manipulation. Implications of these findings for the development of early impulse control and cognitive functioning are considered. Results show that individual differences in impulse control during this time period are related to individual differences in disciplinary style, which are related to characteristics of the physical environment, compliance to maternal demands, and infant performance on standardized intelligence tests. Findings illustrate the importance of a multimethod approach to developing impulse controls. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Numerical Simulation of Anisotropic Shrinkage in a 2D Compact of Elongated Particles

Microstructural evolution during simple solid-state sintering of two-dimensional compacts of elongated particles packed in different arrangements was simulated using a kinetic, Monte Carlo model. The model used simulates curvature-driven grain growth, pore migration by surface diffusion, vacancy formation, diffusion along grain boundaries, and annihilation. Only the shape of the particles was anisotropic; all other extensive thermodynamic and kinetic properties such as surface energies and diffusivities were isotropic. We verified our model by simulating sintering in the analytically tractable cases of simple-packed and close-packed, elongated particles and comparing the shrinkage rate anisotropies with those predicted analytically. Once our model was verified, we used it to simulate sintering in a powder compact of aligned, elongated particles of arbitrary size and shape to gain an understanding of differential shrinkage. Anisotropic shrinkage occurred in all compacts with aligned, elongated particles. However, the direction of higher shrinkage was in some cases along the direction of elongation and in other cases in the perpendicular direction, depending on the details of the powder compact. In compacts of simple-packed, mono-sized, elongated particles, shrinkage was higher in the direction of elongation. In compacts of close-packed, mono-sized, elongated particles and of elongated particles with a size and shape distribution, the shrinkage was lower in the direction of elongation. The results of these simulations are analyzed, and the implication of these results is discussed.     

Egoistic and nonegoistic motives in social dilemmas.

Discusses research trends regarding social dilemmas and the conflict between individual and societal interest in these issues. It is suggested that most current research on social dilemmas involve behavioral, cognitive, or social approaches that reflect an egoistic bias. It is argued that this bias limits the number of types of solutions to dilemmas that psychologists investigate and that egoistically based solutions to social dilemmas are not adequate in many real-world dilemmas. It is contended that the only 2 methods of promoting cooperations that are possible from an individualistic, egoistic perspective are reducing the net costs of cooperation through material or social rewards and punishments and convincing individuals that their behavior will affect the dilemma outcome. These solutions, it is argued, are inadequate to solve many real-world dilemmas. Several nonegoistic solutions to social dilemmas, involving altruistic, group-egoistic, and moral motives, are proposed as more viable solutions to social dilemmas. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Voluntary exercise influences behavioral development in rats exposed to alcohol during the neonatal brain growth spurt.

Children exposed to alcohol prenatally may suffer from severe brain damage, expressed as a variety of behavioral problems, including hyperactivity and learning deficits. There is a critical need to identify effective treatments for fetal alcohol effects. Physical exercise enhances cognitive ability and increases neurogenesis in the hippocampus, a brain area important for learning and memory. Thus, the present study examined whether physical exercise might reduce the severity of alcohol-induced behavioral alterations. Sprague-Dawley rats were intubated with 5.25 g/kg/day ethanol during the third trimester equivalent (postnatal days [PDs] 4-9). Intubated sham control and nontreated controls were included. From PD 21 to PD 51, half of the subjects were given access to running wheels. On PD 52, subjects were tested on the Morris water maze, and on PD 60, open field activity levels were measured. Morris maze performance was significantly impaired among ethanol-exposed subjects; exercise significantly improved performance of all groups. Similarly, ethanol-exposed subjects were overactive in the open field, an effect attenuated with exercise. In sum, these data suggest that exercise may increase neuronal plasticity not only in controls, but also in subjects exposed to alcohol during development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is reading important in reading-readiness programs? A randomized field trial with teachers as program implementers.

The purpose of the present study was to examine the effectiveness and feasibility of phonological awareness training, with and without a beginning decoding component. 33 teachers in 8 urban schools were assigned randomly within their schools to 3 groups: control, phonological awareness training, and phonological awareness training with beginning decoding instruction and practice. Following training, teachers in the 2 treatment groups conducted the treatments for about 20 wks. In each teacher's class, pre- and posttreatment data were collected on 12–14 children (N?=?404); 312 children were tested again the following fall. At the end of kindergarten, the 2 treatment groups performed comparably and outperformed controls on the phonological awareness measures. On alphabetic (reading and spelling) tasks, however, the group participating in phonological awareness training with beginning decoding instruction did better than the other 2 groups. In the fall of the next year, many of these between-group differences remained but were less impressive. Implications are discussed for bridging research and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Consumer confidence in the safety of food in Canada and the Netherlands: The validation of a generic framework

A thorough understanding of consumer confidence in the safety of food and the factors by which this is influenced is necessary for the development of adequate and effective risk management and communication regarding food safety issues. As food chains become globalized, risk management and communication are increasingly applied at international levels. As a consequence, cross-culturally valid theoretical models are needed to investigate consumer confidence in the safety of food. In this study, consumer confidence in the safety of food in Canada and the Netherlands was systematically compared. On the basis of two nationally representative samples, it was examined to what extent differences in consumer confidence between the two countries resulted from differences in the relative importance of the determinants of confidence, and differences in the means of the constructs. No differences between Canada and the Netherlands were found regarding the relative importance of the determinants, which provides support for the generalizability of the framework. However, results indicated that Dutch consumers had a higher level of optimism and a lower level of pessimism regarding the safety of food, which appeared to be mainly related to Dutch consumers’ lower level of concern about factors related to production. The results also indicated cross-national differences in consumer recall of food safety issues in the media.