Knowledge of strategies for dealing with everyday problems from childhood through adolescence.

This study examined the knowledge that children (5th grade) and adolescents (8th and 11th grade) have of the effectiveness of strategies for dealing with everyday problems. Two hundred seventeen individuals rated the effectiveness of six strategies presented as solutions to 20 everyday problems (in school or out of the school setting) before and after information was given that added or removed an obstacle from the problem. Strategy effectiveness was dependent on the context of the specific problem. Age differences (favoring older adolescents) and gender differences (favoring females) were found when students' strategy knowledge was compared with teachers' strategy knowledge. Students' strategy knowledge was related to teachers', parents', and students' ratings of the student's practical intellectual skills as well as to achievement test scores and grades. Implications for the relation between academic and everyday intelligence are drawn. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual search for natural grains in pigeons (Columba livia): Search images and selective attention.

The experiments reported here were designed to test the suggestion of many researchers that selective attention to visual features of a prey can account for search-image effects. In 3 experiments pigeons ate wheat and vetch grains presented on multicolored and gray gravel trays. In Experiment 1 search-image effects were evident when grains were cryptic but not when they were conspicuous. Experiment 2 demonstrated that search images can be activated when the grains encountered are either cryptic or conspicuous but that search images affect search performance only when the grains are cryptic. Experiment 3 demonstrated that search images are short-term in nature: A 3-min delay between successive encounters with a type of grain disrupted an activated search image. The discussion addresses how these results further develop a model in which search images are viewed as selective attention to visual features of a prey. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of self-efficacy, goals, and task strategies on task performance.

Manipulated self-efficacy and task strategies in the training of 209 undergraduates under high strategy, low strategy, and control conditions. Ss underwent 5 trials and were administered a self-efficacy scale after each trial. Results show that ability, past performance, and self-efficacy were the major predictors of goal choice. Ability, self-efficacy, goals, and task strategies were related to task performance. Self-efficacy was more strongly related to past performance than to future performance but remained a significant predictor of future performance even when past performance was controlled. Self-efficacy ratings for moderate to difficult levels of performance were the best predictors of future performance; a reanalysis of 2 previous goal-setting studies by the first author confirms this finding. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the Initiation Factors in mRNA Start Site Selection and fMet-tRNA Recruitment by Bacterial Ribosomes

Translation initiation is a complex, multi-step process of fundamental importance in all kingdoms of life, during which the start site of the genetic message transmitted in the form of an RNA molecule (mRNA) is selected, and the level of translation determined. Being the slowest step of protein synthesis, initiation is the phase most often subject to regulation. Here we review, in a historical perspective and focusing mainly on results from our laboratory, the development of our perception of the mechanisms by which the most relevant steps of this pathway occur in bacteria. In particular, we describe: (a) the mechanistics and kinetics of translation initiation; (b) properties of mRNAs with and without Shine–Dalgarno sequence relevant for initiation site selection and translational efficiency; c) ribosomal binding and dissociation of the initiation factors, formation and properties of translation initiation intermediates; (d) the mechanisms by which translation initiation fidelity is ensured. Finally, we provide a short survey of the known translation initiation inhibitors.     

Electrical Current Signatures of DNA Base Modifications in Single Molecules Immobilized in the α-Hemolysin Ion Channel

Nanopore technology holds high potential for next-generation DNA sequencing. This method operates by drawing an individual single-stranded DNA molecule through a nanoscale pore, while monitoring the current deflections that occur as the DNA passes through. Individual current levels for the four DNA nucleotides have been established by immobilization of an end biotinylated strand in the pore, in which the nucleotide of interest is suspended at the most sensitive region of the ion channel. Due to the inherent reactivity of DNA bases, many modified nucleotides in the genome exist as a result of oxidative and UV insults, among others. Herein, the current levels for common DNA damage lesions 8-oxo-7,8-dihydroguanine, spiroiminodihydantoin, guanidinohydantoin, uridine, abasic sites, thymine dimers, thymine glycol, and 5-iodocytosine were assessed through immobilization experiments. In some cases, the current difference between the damaged and canonical nucleotides was not well resolved; therefore, we took advantage of the chemical reactivity of the new functional groups present to make amine adducts that shifted the current levels outside the range of the native nucleotides. Among the adducts studied, only the 2-aminomethyl-18-crown-6 adduct was able to give a large current shift in the immobilization experiment, as well as being observed in a translocation experiment. The results show potential in providing current-level modulators for identification of some types of DNA damage. In principle, any DNA base modification that can be converted chemically or enzymatically into an abasic site could be identified in this way.     

LAS glass–ceramic scaffolds by three-dimensional printing

Highly porous (>60% open porosity) glass–ceramic scaffolds with remarkable mechanical properties (compression strength of ～15 MPa) were produced by indirect 3D printing. Precursor glass powders were printed into 3D ordered structures and then heat treated to sinter and develop crystalline phases. The final glass–ceramic contained a β-spodumene solid solution together with a secondary phase of lithium disilicate.The precision of the printed geometry and the density of the struts in the scaffold depended on several processing parameters (e.g. powder size and flowability, layer thickness) and were improved by increasing the binder saturation and drying time. Two types of powders with different particle size distribution (PSD) and flowability were used. Powders with a larger PSD, could be processed within a wider range of printing parameters due to their good flowability; however, the printing precision and the struts density were lower compared to the scaffolds printed using the powder in a smaller average PSD.     

Synchrony effects in inhibitory control over thought and action.

Two experiments explore whether synchrony between peak circadian arousal periods and time of testing influences inhibitory efficiency for younger and older adults. Experiment 1 assesses inhibitory control over no-longer-relevant thoughts, and Experiment 2 assesses control over unwanted but strong responses, as well as performance on neuropsychological tasks that index frontal function. Inhibitory control is greatest at optimal times for both age groups and is generally greater for younger than for older adults. Performance on 2 neuropsychological measures (Stroop and Trails) also changes over the day, at least for older adults, and is correlated with inhibitory indexes, suggesting that for older adults changes in inhibition may be mediated by circadian variations in frontal functioning. By contrast, access to well-learned responses is not vulnerable to synchrony or age effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depleted parental psychological resources as mediators of the association of income with adherence and metabolic control.

For adolescents with Type 1 diabetes, lower family income may be associated with poorer diabetes management through depleted parental psychological resources (i.e., higher parental depressive symptoms, lower parental acceptance). Adolescents (N = 252; 46% male) aged 10–14 years with Type 1 diabetes assessed the acceptance of their mother and father (e.g., “gives me the feeling that she likes me as I am”; “she doesn't feel she has to make me over into someone else”). Mothers provided information on family income and demographics. Both mothers and fathers reported their depressive symptoms. HbA1c scores were indexed via medical records. Lower family income was associated with higher (i.e., worse) HbA1c, more mother and father depressive symptoms, and less acceptance from both parents. Mediation analyses revealed that the relationship of lower family income with metabolic control occurred indirectly through lower maternal and paternal acceptance and lower adherence. Lower family income may impair the quality of parent—adolescent relationships that are beneficial for good diabetes management. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Temporal Specificity of Extinction in Autoshaping.

Three experiments investigated the effects of varying the conditioned stimulus (CS) duration between training and extinction. Ring doves (Streptopelia risoria) were autoshaped on a fixed CS-unconditioned stimulus (US) interval and extinguished with CS presentations that were longer, shorter, or the same as the training duration. During a subsequent test session, the training CS duration was reintroduced. Results suggest that the cessation of responding during an extinction session is controlled by generalization of excitation between the training and extinction CSs and by the number of nonreinforced CS presentations. Transfer of extinction to the training CS is controlled by the similarity between the extinction and training CSs. Extinction learning is temporally specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)