Transmission electron microscopy study of a new silicon nitride phase

An abnormally large phase, which was found in the precursor-derived Si 3.0 B 1.1 C 5.3 N 3.0 ceramics after crystallization under a nitrogen pressure of 100bar at 1800C for 3h, has been characterized by means of transmission electron microscopy and electron-energy-loss spectroscopy (EELS). EELS analysis shows that this phase consists of only silicon and nitrogen, no other elements being detected. The analysis of selected-area diffraction and convergent-beam electron diffraction in conjunction with EELS reveals that the unknown phase is a variant of silicon nitride. It has a hexagonal structure with lattice parameters a =0.737nm and c =0.536nm, and the space group P62c. .     

Implicit Attitudes Toward Arab-Muslims and the Moderating Effects of Social Information

Three studies examined the relative valence and strength of implicit attitudes toward Arab-Muslims using the Implicit Association Test (IAT) while exploring the moderation of such implicit effects. Studies have suggested that repeated exposure to information associating members of a social group (e.g., Arab-Muslims) with evaluative attributes (e.g., terrorism) might create automatic attitudes toward them. Consistent with this notion, the IAT results indicated strong implicit preference for White over Arab-Muslim, whereas the magnitude of such a bias was substantially diminished when assessed by explicit measures (Study 1). It is also interesting to note that participants exhibited implicit preference for Black over Arab-Muslim when measured by the IAT, whereas no difference was found between the 2 groups in stimulus familiarity and in explicit attitudes (Studies 2 and 3). However, such implicit effects were moderated when participants were exposed to positive information about Arab-Muslims (Study 3). Theoretical and practical implications of these findings are further discussed.     

Adaptive memory: enhanced source memory for animate entities

ABSTRACT

The animacy effect refers to enhanced memory for animate over inanimate items. In two studies, we examined whether this memory advantage generalises to source memory. A multinomial processing tree model was used to disentangle item recognition, source memory, and guessing processes. In Study 1, animate and inanimate words were presented at different spatial locations on the screen. Animacy was associated with enhanced source memory for the spatial locations of the items. In Study 2, pseudowords were associated with animate and inanimate properties. Replicating previous results, the pseudowords were better remembered when they were associated with animate properties than when they were associated with inanimate properties. What is more, participants had enhanced source memory for the association between the pseudowords and the animate properties. The results strengthen the idea that animate items are associated with richer mnemonic representations than inanimate items.     

Book Reviews

Abstract

The aim of this paper is to identify what I take to be the main conceptual problem in Lewis’ semantics for counterfactuals when the Limit Assumption (LA) is not satisfied, what I call the Discrimination Problem (DP), and to present and discuss a modification of Lewis’ semantics that aims at solving DP. First, I outline Lewis’ semantics, highlighting the aspects that will be relevant for our discussion. Second, I present DP and discuss it with a heuristic example. Third, I present the new proposal and comment some formal consequences and the objections they give rise to. Fourth, I present an allegedly equivalent version of the proposal and discuss the difference between counterfactuals and strict conditionals. Finally, I defend that the two proposals are different and argue for the first one as the best way of capturing two intuitions that seem in conflict when the LA is not satisfied. I conclude with a dilemma: either the proposal here defended works or LA is inescapable. Thus, if the proposal doesn’t work, the paper must then be considered as an indirect defense of the Limit Assumption.     

Coping in relationships: the interplay between individual and dyadic coping and their effects on relationship satisfaction

The main aim of the present study was to determine how individual and dyadic coping efforts are related in the context of relationships. This aim was achieved by studying partners simultaneously and taking into account the interdependent nature of couple data. Specifically tested was whether dyadic coping mediates the influence of individual coping, and whether there is a mutual influence of partners' dyadic coping. Cross-sectional data of 240 German couples were analyzed using structural equation modeling. Results indicated that dyadic coping is a stronger predictor of relationship satisfaction than individual coping, and that it mediates the individual coping efforts. Mutual influence could be demonstrated for pragmatic coping but not for emotional coping. This research highlights the importance of dyadic coping by focusing on the ways in which couples cope together.     

Establishing a relational field that fosters learning processes: Some tentative propositions derived from trainee experiences

In this article, we look at the recent introduction of more relational-oriented learning principles and how they translate into practice by documenting the experiences of both trainees and instructors. It became clear that actors held different opinions and viewpoints on learning objectives and process ingredients for achieving these objectives. This divergence in opinions resulted in an “impoverished” learning trajectory. We suggest that remedying this situation implies introducing reflexivity regarding learning processes or, stated otherwise, addressing “meta-cognitions” that participants inevitably bring to the process as they affect the way in which people engage in the relational field that encompasses the learning trajectory. Despite some recent arguments in favour of a distinction between cognitive and meta-cognitive mediation, we argue for a similar approach with respect to both types of mediation. We end this article by suggesting that designing learning trajectories with this dual concern in mind might open the road to “learning to learn”.     

A Systematic Review of Propensity Score Methods in the Social Sciences

The use of propensity scores in psychological and educational research has been steadily increasing in the last 2 to 3 years. However, there are some common misconceptions about the use of different estimation techniques and conditioning choices in the context of propensity score analysis. In addition, reporting practices for propensity score analyses often lack important details that allow other researchers to confidently judge the appropriateness of reported analyses and potentially to replicate published findings. In this article we conduct a systematic literature review of a large number of published articles in major areas of social science that used propensity scores up until the fall of 2009. We identify common errors in estimation, conditioning, and reporting of propensity score analyses and suggest possible solutions.     

Family Influences on the Long Term Post-Disaster Recovery of Puerto Rican Youth

This study focused on characteristics of the family environment that may mediate the relationship between disaster exposure and the presence of symptoms that met DSM-IV diagnostic criteria for symptom count and duration for an internalizing disorder in children and youth. We also explored how parental history of mental health problems may moderate this mediational model. Approximately 18 months after Hurricane Georges hit Puerto Rico in 1998, participants were randomly selected based on a probability household sample using 1990 US Census block groups. Caregivers and children (N?=?1,886 dyads) were interviewed with the Diagnostic Interview Schedule for Children and other questionnaires in Spanish. Areas of the family environment assessed include parent-child relationship quality, parent-child involvement, parental monitoring, discipline, parents’ relationship quality and parental mental health. SEM models were estimated for parents and children, and by age group. For children (4–10 years old), parenting variables were related to internalizing psychopathology, but did not mediate the exposure-psychopathology relationship. Exposure had a direct relationship to internalizing psychopathology. For youth (11–17 years old), some parenting variables attenuated the relation between exposure and internalizing psychopathology. Family environment factors may play a mediational role in psychopathology post-disaster among youth, compared to an additive role for children. Hurricane exposure had a significant relation to family environment for families without parental history of mental health problems, but no influence for families with a parental history of mental health problems.