The Peierls-Nabarro model revisited

We re-examine two important issues within the Peierls-Nabarro model, which are critical in obtaining accurate values for the Peierls stress. The first is related to the sampling scheme (double versus single counting) of the misfit energy across the glide plane and the second is the effect of atomic relaxation on the Peierls stress. We argue that the double-counting scheme is physically more appropriate. An analytical formula is derived for the Peierls stress of dislocations in alternating lattices. The atomic relaxation is shown to play an important role on the Peierls stress for narrow dislocations.     

The effects of distinctiveness on memory and metamemory for face–name associations

We examined the influence of face and name distinctiveness on memory and metamemory for face–name associations. Four types of monitoring judgements were solicited during encoding and retrieval of face–name pairs that contained distinct or typical faces (Experiment 1) or names (Experiment 2). The beneficial effects of distinctiveness on associative memory were symmetrical between faces and names, such that relative to their typical counterparts, distinct faces enhanced memory for names, and distinct names enhanced memory for faces. These effects were also apparent in metamemory. Estimates of prospective and retrospective memory performance were greater for face–name associations that contained a distinct face or name compared with a typical face or name, regardless of whether the distinct item was a cue or target. Moreover, the predictive validity of prospective monitoring improved with name distinctiveness, whereas the predictive validity of retrospective monitoring improved with facial distinctiveness. Our results indicate that distinctiveness affects not only the strength of the association between a face and a name, but also the ability to monitor that association.     

Young adult e-cigarette users’ reasons for liking and not liking e-cigarettes: A qualitative study

Objective: To gain an in-depth understanding of what young adult electronic- or e-cigarette users like or dislike about e-cigarettes. We aimed to determine the reasons that may encourage young adults to use e-cigarettes or discourage them from using e-cigarettes.

Design: Twelve focus group discussions were conducted with 62 current daily e-cigarette users (63% men) of mean age = 25.1 years (standard deviation = 5.5). Data were analysed following principles of inductive content analysis.

Results: Results indicated 12 categories of reasons for liking e-cigarettes (e.g. recreation, smoking cessation) and 6 categories of reasons for not liking e-cigarettes (e.g. poor product quality, poor smoking experience).

Conclusions: Young adults’ motives for using or not using e-cigarettes appear to be varied and their relative importance in terms of predicting e-cigarette use initiation, dependence, and cigarette/e-cigarette dual use needs to be carefully studied in population-based, empirical studies. The current findings suggest that e-cigarettes may serve social, recreational, and sensory expectancies that are unique relative to cigarettes and not dependent on nicotine. Further, successful use of e-cigarettes in smoking cessation will likely need higher standards of product quality control, better nicotine delivery efficiency and a counselling component that would teach smokers how to manage e-cigarette devices while trying to quit smoking cigarettes.     

Memory for Faces in Children with Autism

Previous research has established that children with Autistic Disorder have deficits in aspects of social cognition and in verbal memory, but research on social memory is limited. Twenty-four autistic boys aged 7 to 12 years and normal controls matched for verbal mental age were administered parallel social and nonsocial matching and memory tasks. Results showed that the children with autism were impaired relative to the normal children on the social (face) memory task only. Furthermore, of the four experimental tasks, the social memory task had the highest and most consistent correlations with measures of social development and adaptive skills. Whereas the normal children used the special status of faces to recall them more easily than objects, the children with autism showed equal recall of objects and faces.     

Impressions at the intersection of ambiguous and obvious social categories: Does gay + Black = likable?

How do perceivers combine information about perceptually obvious categories (e.g., Black) with information about perceptually ambiguous categories (e.g., gay) during impression formation? Given that gay stereotypes are activated automatically, we predicted that positive gay stereotypes confer evaluative benefits to Black gay targets, even when perceivers are unaware of targets' sexual orientations. Participants in Study 1 rated faces of White straight men as more likable than White gay men, but rated Black men in the opposite manner: gays were liked more than straights. In Study 2, participants approaching Whites during an approach–avoidance task responded faster to straights than gays, whereas participants approaching Blacks responded faster to gays than straights. These findings highlight the striking extent to which less visible categories, like sexual orientation, subtly influence person perception and determine the explicit and implicit evaluations individuals form about others.     

Did Kant Conflate the Necessary and the A Priori?

It is commonly accepted by Kant scholars that Kant held that all necessary truths are a priori, and all a priori knowledge is knowledge of necessary truths. Against the prevailing interpretation, I argue that Kant was agnostic as to whether necessity and a priority are co‐extensive. I focus on three kinds of modality Kant implicitly distinguishes: formal possibility and necessity, empirical possibility and necessity, and noumenal possibility and necessity. Formal possibility is compatibility with the forms of experience; empirical possibility is compatibility with the causal powers of empirical objects; noumenal possibility is compatibility with the causal powers of things in themselves. Because we cannot know the causal powers of things in themselves, we cannot know what is noumenally necessary and what is noumenally contingent. Consequently, we cannot know whether noumenal necessity is co‐extensive with a priority. Therefore, for all we know, some a priori propositions are noumenally contingent, and some a posteriori propositions are noumenally necessary. Thus, contrary to the received interpretation, Kant distinguishes epistemological from metaphysical modality.     

What does a general factor of personality look like in unshared environmental variance?

A general factor of personality (GFP) was obtained solely from unshared environment, by deriving it from the intercorrelations of monozygotic twin differences. This GFP was compared with a GFP derived from correlations reflecting all three components of variance—genes, shared environment, and unshared environment. In two large samples of adult Australian twins, for the items of two questionnaires, the two approaches gave virtually identical GFPs. However, in a sample of adolescent Australian twins, the two GFPs were correlated but distinct.