Differential susceptibility to discipline: The moderating effect of child temperament on the association between maternal discipline and early childhood externalizing problems.

This study investigated the interaction of child temperament and maternal discipline in the prediction of externalizing problems in early childhood. Interaction effects were evaluated in a sample of 227 one- to three-year-old children with relatively high externalizing problems scores on the Child Behavior Checklist/1 1/2-5. Child temperament was reported by the mothers, maternal discipline was observed in a laboratory session, and child outcome measures included both mother-reported externalizing problems and observed physical aggression. Results indicate that children with difficult temperaments are more susceptible to negative discipline (i.e., they showed more externalizing problems) as well as more susceptible to positive discipline (i.e., they showed fewer externalizing problems and less physical aggression), as compared with children with relatively easy temperaments. These findings provide empirical evidence for the differential susceptibility hypothesis and suggest directions for enhancing the effectiveness of interventions aimed at reducing early childhood externalizing problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pretesting effects in retrospective pretest-posttest designs.

Two studies evaluated communication skills training by using a pretest-posttest design, including retrospective pretest ratings, to control for response shift bias. A response shift is a change in a subject's internal standard for determining his or her level of functioning on a given dimension. In Exp 1, Ss were 37 hospital employees. Data indicated that the self-report pretest exerted a clear effect on subsequent self-report posttest and retrospective pretest ratings. Training was ineffective and a response shift did not occur. Experimental Ss could not remember and control Ss could remember their pretreatment ratings to a reasonable extent. In Exp 2, Ss were 58 3rd-year dental students. Results show that the training was effective. A behavioral pretest administered prior to the self-report pretest prevented a response shift from occurring. This finding gives empirical support to the contention that Ss' lack of sufficient information about their level of functioning at pretest may be a causal determinant of the response shift. Data also indicate that the retrospective pretest is robust for procedural differences in administering this instrument. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The glio-toxic mechanism of alpha-aminoadipic acid on cultured astrocytes

Porcine pancreatic phospholipase A2 (PLA2) hydrolyses phosphatidylcholine when in the lamellar state as well as in the micellar state. We have found that alpha-tocopherol, the most active form of vitamin E, is able to inhibit PLA2 activity only toward lamellar fluid membranes, thus protecting phospholipids toward this lytic enzyme. This compound decreases both the initial rate and the extent of hydrolysis. The inhibition is of the non-competitive type and the evidence strongly suggests that it is due to an effect of alpha-tocopherol on the substrate, i.e. the membrane, and not on the enzyme itself. Other tocopherols, such as the isomers beta-, gamma- and delta-tocopherol also display PLA2 inhibition but consecutively to a lower extent. The grade of inhibition of PLA2 activity by tocopherols correlates well with their biological activity and with their location in the bilayer as shown by fluorescence quenching. Cholesterol does not inhibit PLA2 activity at concentrations even higher than those of tocopherols, indicating that the effect of tocopherols is not due to alteration of membrane fluidity. The possible mechanisms underlying the different behaviour of tocopherol isomers as PLA2 inhibitors are discussed considering its biological significance as membrane stabilizers, suggesting biological actions of compounds with vitamin E activity other than their classical roles as antioxidants.     

Catching a viral video

The sharing and re-sharing of videos on social sites, blogs e-mail, and other means has given rise to the phenomenon of viral videos—videos that become popular through internet sharing. In this paper we seek to better understand viral videos on YouTube by analyzing sharing and its relationship to video popularity using millions of YouTube videos. The socialness of a video is quantified by classifying the referrer sources for video views as social (e.g. an emailed link, Facebook referral) or non-social (e.g. a link from related videos). We find that viewership patterns of highly social videos are very different from less social videos. For example, the highly social videos rise to, and fall from, their peak popularity more quickly than less social videos. We also find that not all highly social videos become popular, and not all popular videos are highly social. By using our insights on viral videos we are able develop a method for ranking blogs and websites on their ability to spread viral videos.     

Activity sequence modelling and dynamic clustering for personalized e-learning

Monitoring and interpreting sequential learner activities has the potential to improve adaptivity and personalization within educational environments. We present an approach based on the modeling of learners?? problem solving activity sequences, and on the use of the models in targeted, and ultimately automated clustering, resulting in the discovery of new, semantically meaningful information about the learners. The approach is applicable at different levels: to detect pre-defined, well-established problem solving styles, to identify problem solving styles by analyzing learner behaviour along known learning dimensions, and to semi-automatically discover learning dimensions and concrete problem solving patterns. This article describes the approach itself, demonstrates the feasibility of applying it on real-world data, and discusses aspects of the approach that can be adjusted for different learning contexts. Finally, we address the incorporation of the proposed approach in the adaptation cycle, from data acquisition to adaptive system interventions in the interaction process.     

How to overcome the detrimental effects of noise in social interaction: The benefits of generosity.

Interpersonal misunderstanding is often rooted in noise, or discrepancies between intended and actual outcomes for an interaction partner due to unintended errors (e.g., not being able to respond to an E-mail because of a local network breakdown). How can one effectively cope with noise in social dilemmas, situations in which self-interest and collective interests are conflicting? Consistent with hypotheses, the present research revealed that incidents of noise exert a detrimental effect on level of cooperation when a partner follows strict reciprocity (i.e., tit for tat) but that this effect can be overcome if a partner behaves somewhat more cooperatively than the actor did in the previous interaction (i.e., tit for tat plus 1). Also, when noise was present, tit for tat plus 1 elicited greater levels of cooperation than did tit for tat, thereby underscoring the benefits of adding generosity to reciprocity in coping with noise in social dilemmas. The Discussion outlines implications of the present work for theories focusing on self-presentation and attribution, communication, and trust and prorelationship behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prion protein fragment primes type 1 astrocytes to proliferation signals from microglia

Giliosis is a hallmark of prion disease. A neurotoxic prion peptide (PrP106-126) induces astrocyte proliferation in the presence of microglia. This peptide also directly enhances microglial proliferation in culture. We have investigated this further to understand the method by which factors released by microglia and PrP106-126 work together to enhance astrocyte proliferation. PrP106-126 in the presence of microglia specifically enhanced type 1 astrocyte proliferation but not Type 2. Astrocytes that do not express the prion protein were more sensitive to oxidative stress and the toxicity of cytosine arabinoside. In the presence of cytosine arabinoside, PrP106-126 was toxic to pure astrocyte cultures. Using conditioned medium from microglia we have shown that PrPc-expressing astrocytes proliferate in response to factors released by microglia stimulated by granulocyte/macrophage colony-stimulating factor. This response is enhanced in the presence of PrP106-126. PrPc-deficient astrocytes do not show this response. These results suggest that astrocytes are primed by PrP106-126 to respond more to factors released by proliferating microglia. Astrocytes may proliferate in this system to escape entering the cell suicide pathway.     

Attachment-based intervention for enhancing sensitive discipline in mothers of 1- to 3-year-old children at risk for externalizing behavior problems: A randomized controlled trial.

The home-based intervention program Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) was tested in a randomized controlled trial with 237 families screened for their 1- to 3-year-old children's relatively high scores on externalizing behavior. VIPP-SD, based on attachment theory and coercion theory, focuses on mirroring and discussing actual parent-child interactions in six 1.5-hr sessions with individual families at home. VIPP-SD proved to be effective in enhancing maternal attitudes toward sensitivity and sensitive discipline and in promoting sensitive discipline interactions in the intervention group as compared with the control group. Moreover, in families with more marital discord and in families with more daily hassles, the intervention resulted in a decrease of overactive problem behaviors in the children. The authors conclude that VIPP-SD should become an important module in attachment-based interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential evolution and differential ant-stigmergy on dynamic optimisation problems

Many real-world optimisation problems are of dynamic nature, requiring an optimisation algorithm which is able to continuously track a changing optimum over time. To achieve this, we propose two population-based algorithms for solving dynamic optimisation problems (DOPs) with continuous variables: the self-adaptive differential evolution algorithm (jDE) and the differential ant-stigmergy algorithm (DASA). The performances of the jDE and the DASA are evaluated on the set of well-known benchmark problems provided for the special session on Evolutionary Computation in Dynamic and Uncertain Environments. We analyse the results for five algorithms presented by using the non-parametric statistical test procedure. The two proposed algorithms show a consistently superior performance over other recently proposed methods. The results show that both algorithms are appropriate candidates for DOPs.