Creep behaviour of ice single crystals loaded in torsion explained by dislocation cross-slip

Torsion creep experiments are carried out in order to understand the physics of ice plasticity. A dislocation spreading mechanism based on double cross-slip of basal dislocations is proposed to explain the strong plastic anisotropy and the power law relationship between stress and strain rates. The scenario is tested using three-dimensional dislocation dynamics simulations. Numerical investigations give a stress exponent n?=?2.3 in agreement with experimental measurements. This dislocation spreading mechanism sheds a new light on the interpretation of former experimental observations.     

Experimental philosophers,conceptual analysts,and the rest of us

Abstract

Theories of personal identity purport to specify truth conditions for sentences of the form ‘x‐at‐t_i is the same person as y‐at‐t_j. Most philosophers nowadays agree that such truth conditions are to be stated in terms of psychological continuity. However; opinions vary as to how the notion of psychological continuity is to be understood. In a recent contribution to this journal, Slors offers an account in which psychological continuity is spelled out in terms of narrative connectedness between mental states.The present paper argues that Slors’ theory either is no theory of personal identity at all or is too weak.Towards the end of the paper, it is indicated how the problem uncovered for Slors’ theory may be avoided.     

What is the future for tool-specific generalized motor programs?

A key issue in cognitive sciences is to understand the cognitive bases of human tool use. Answers have been provided by two competing approaches. The manipulation-based approach assumes that humans can use tools because of the ability to store sensorimotor knowledge about how to manipulate tools. By contrast, for the reasoning-based approach, human tool use is based on the ability to reason about physical object properties. Recently, Caruana and Cuccio proposed a kind of reconciliation, based on the distinction between three types of abductive inference, involving a different contribution of motor and cognitive elements: Automatic abduction (motor + and cognitive-), abduction by selection (motor ± and cognitive±) and creative abduction (motor- and cognitive+). This perspective offers new interesting avenues. Nevertheless, it is also subject to several theoretical and epistemological limitations, which make it in its present form inappropriate for the study of the cognitive bases of human tool use. This article aims to discuss these limitations.     

Integration of parafoveal orthographic information during foveal word reading: beyond the sub-lexical level?

Prior research has shown that processing of a given target word is facilitated by the simultaneous presentation of orthographically related stimuli in the parafovea. Here we investigate the nature of such spatial integration processes by presenting orthographic neighbours of target words in the parafovea, considering that neighbours have been shown to inhibit, rather than facilitate, recognition of target words in foveal masked priming research. In Experiment 1, we used the gaze-contingent boundary paradigm to manipulate the parafoveal information subjects received while they fixated a target word within a sentence. In Experiment 2, we used the Flanking Letters Lexical Decision paradigm to manipulate parafoveal information while subjects read isolated words. Parafoveal words were either a higher-frequency orthographic neighbour of targets words (e.g., blue-blur) or a high-frequency unrelated word (e.g., hand-blur). We found that parafoveal orthographic neighbours facilitated, rather than inhibited, processing of the target. Thus, the present findings provide further evidence that orthographic information is integrated across multiple words and suggest that either the integration process does not enable simultaneous access to those words’ lexical representations, or that lexical representations activated by spatially distinct stimuli do not compete for recognition.     

Complementary Variable- and Person-Centered Approaches to the Dimensionality of Psychometric Constructs: Application to Psychological Wellbeing at Work

Purpose

This study illustrates complementary variable- and person-centered approaches allowing for a more complete investigation of the dimensionality of psychometric constructs. Psychometric measures often assess conceptually related facets of global overarching constructs based on the implicit or explicit assumption that these overarching constructs exist as global entities including conceptually related specificities mapped by the facets. Proper variable- and person-centered methodologies are required to adequately reflect the dimensionality of these constructs.

Design/Methodology/Approach

We illustrate these approaches using employees’ (N = 1077) ratings of their psychological wellbeing at work.

Findings

The results supported the added value of the variable-centered approach proposed here, showing that employees’ ratings of their own wellbeing simultaneously reflect a global overarching wellbeing construct, together with a variety of specific wellbeing dimensions. Similarly, the results show that anchoring person-centered analyses into these variable-centered results helps to achieve a more precise depiction of employees’ wellbeing profiles.

Implications

The variable-centered bifactor exploratory structural equation modeling (ESEM) framework provides a way to fully explore these sources of psychometric multidimensionality. Similarly, whenever constructs are characterized by the co-existence of overarching constructs with specific dimensions, it becomes important to properly disaggregate these two components in person-centered analyses. In this context, person-centered analyses need to be clearly anchored in the results of preliminary variable-centered analyses.

Originality/Value

Substantively, this study proposes an improved representation of employees’ wellbeing at work. Methodologically, this study aims to pedagogically illustrate the application of recent methodological innovations to organizational researchers.

     

A demonstration of dual-task performance without interference in some older adults

Highly efficient dual-task processing is demonstrated when reaction time to each of two tasks does not differ between the dual-task situation and the single-task situation. This has been demonstrated reliably in younger adults; nevertheless, the two extant studies of extensive dual-task training did not find evidence for it in any elderly adult. The origins of age-related differences after training were explored in a study in which the stimuli for the two tasks were perfectly redundant although two distinct responses were required. The dual-task situation thus greatly reduced the demands of stimulus categorization while still requiring two response selections and two response executions. After only limited training 8 of 8 younger adults and 5 of 8 older adults showed performance consistent with highly efficient processing. Three older adults failed to show this even after 12 training sessions. The results implicate stimulus categorization more than response selection as an important locus of inefficient dual-task processing, particularly for older adults.     

Early- and late-onset blindness both curb audiotactile integration on the parchment-skin illusion

It has been shown that congenital blindness can lead to anomalies in the integration of auditory and tactile information, at least under certain conditions. In the present study, we used the parchment-skin illusion, a robust illustration of sound-biased perception of touch based on changes in frequency, to investigate the specificities of audiotactile interactions in early- and late-onset blind individuals. Blind individuals in both groups did not experience any illusory change in tactile perception when the frequency of the auditory signal was modified, whereas sighted individuals consistently experienced the illusion. This demonstration that blind individuals had reduced susceptibility to an auditory-tactile illusion suggests either that vision is necessary for the establishment of audiotactile interactions or that auditory and tactile information can be processed more independently in blind individuals than in sighted individuals. In addition, the results obtained in late-onset blind participants suggest that visual input may play a role in the maintenance of audiotactile integration.     

Religion as Cultural Models: Developing an Emic Measure of Religiosity

Despite a century's worth of work, lacunae remain in our understanding of the religion‐health relationship. Scholars in this field have called for increasingly sophisticated conceptualizations of religiosity that refine its connection to well‐being, accounting for both positive and negative associations, while being sensitive to the cultural variations in the experience of religion. This article argues that cognitive anthropological methods provide a novel approach to these issues by conceptualizing aspects of religion as culturally shared “styles of life.” Specifically, the combined approaches of cultural consensus and cultural consonance provide an emically valid measure of religiosity that is then linked to health through the psychosocial stress paradigm. Utilizing research among Brazilian Pentecostals within the state of São Paulo, this intrareligious study evaluates the predictive power of religious cultural consonance relative to widely used and established religiosity scales. Religious consonance is found to have a stronger correlation with psychological well‐being than comparable measures, suggesting that existing standardized measures miss important dimensions of the religion‐health relationship. As such, this article outlines an important area of collaboration between anthropologists and other religion‐health researchers.     

Object manipulability affects children’s and adults’ conceptual processing

Research on kinds of concepts indicates that children use perceptual and functional information differently to form natural and artifact concepts. Beyond object domain, object manipulability appears to be a decisive factor in adult conceptual processing. Thus, the effect of object manipulability on conceptual processing was tested in 5- and 7-year-olds and adults using a picture matching task. Reaction times for identifying conceptual relations on the basis of perceptual similarity (e.g., jacket-coat) and contextual/functional information (e.g., jacket-hanger) were analyzed according to object manipulability and domain. Both children and adults were faster to identify contextual/functional relations for manipulable than for nonmanipulable objects. Conversely, they were faster to identify perceptual similarity relations for nonmanipulable than for manipulable objects, particularly for natural concepts. Results reveal an early distinction between concepts of manipulable and nonmanipulable objects. Implications for further research on concept formation and for embodied views of concepts are discussed.