An atomistic modelling and statistical analysis study of crack–void interaction in Aluminum

The interaction between a brittle crack and pre-existing void in front of the crack tip was studied in the realm of molecular dynamics simulations at the nanoscale in face centred cubic Al within the framework of embedded-atom method. The results provide corroborative evidence of the fact that presence of a void in front of a running crack deters further crack growth. By performing an extensive series of simulations with different void sizes and crack-void distances coupled with statistical analysis, it has been found that (1) major role of voids is to decrease the fracture stress with increasing void size, in addition to slight increase in strain at which the crack growth occurs and the consequent strain to fracture, (2) fracture stress for a constant void size follows a sinusoidal distribution by varying the crack-void distance and (3) it is the void size that is most crucial in dictating the fracture properties of the material, rather than the void placement.     

Exploring counsellor perceptions of the impact of counselling supervision on clients

This qualitative study explores counsellors’ experiences and perceptions of how counselling supervision impacts upon their clients. Data collection combined open‐ended questionnaires (n = 13) and semi‐structured interviews (n = 6). The findings indicate that supervision impacts client work both helpfully and unhelpfully. Areas that emerged as having the most direct impact on client work were the counselling relationship dynamics and self‐awareness, professional development, emotional support, clients not discussed in supervision and the quality of the supervisory relationship. Congruence and confidence were the most direct link between supervision and client work.     

Preserving integrity against colonization

Genuine reconciliation between first- and third-person methodologies and knowledge requires respect for both phenomenological and scientific epistemologies. Recent pragmatic, theoretical, and verbal attempts at reconciliation by cognitive scientists compromise phenomenological method and knowledge. The basic question is thus: how do we begin reconciling first- and third-person epistemologies? Because life is the unifying concept across phenomenological and cognitive disciplines, a concept consistently if differentially exemplified in and by the phenomenon of movement, conceptual complementarities anchored in the animate properly provide the foundation for reconciliation. Research by people in neuroscience and in dynamic systems theory substantiate this thesis, providing fundamental examples of conceptual complementarity between phenomenology and science.     

Sequencing and Optimization Within an Embodied Task Dynamic Model

A model of gestural sequencing in speech is proposed that aspires to producing biologically plausible fluent and efficient movement in generating an utterance. We have previously proposed a modification of the well‐known task dynamic implementation of articulatory phonology such that any given articulatory movement can be associated with a quantification of effort ( Simko & Cummins, 2010 ). To this we add a quantitative cost that decreases as speech gestures become more precise, and hence intelligible, and a third cost component that places a premium on the duration of an utterance. Together, these three cost elements allow us to derive algorithmically optimal sequences of gestures and dynamical parameters for generating articulator movement. We show that the optimized movement displays many timing characteristics that are representative of real speech movement, capturing subtle details of relative timing between gestures. Optimal movement sequences also display invariances in timing that suggest syllable‐level coordination for CV sequences. We explore the behavior of the model as prosodic context is manipulated in two dimensions: clarity of articulation and speech rate. Smooth, fluid, and efficient movements result.     

The cognitive dynamics of negated sentence verification

We explored the influence of negation on cognitive dynamics, measured using mouse-movement trajectories, to test the classic notion that negation acts as an operator on linguistic processing. In three experiments, participants verified the truth or falsity of simple statements, and we tracked the computer-mouse trajectories of their responses. Sentences expressing these facts sometimes contained a negation. Such negated statements could be true (e.g., "elephants are not small") or false (e.g., "elephants are not large"). In the first experiment, as predicted by the classic notion of negation, we found that negation caused more discreteness in the mouse trajectory of a response. The second experiment induced a simple context for these statements, yet negation still increased discreteness in trajectories. A third experiment enhanced the pragmatic context of sentences, and the discreteness was substantially diminished, with one primary measure no longer significantly showing increased discreteness at all. Traditional linguistic theories predict rapid shifts in cognitive dynamics occur due to the nature of negation: It is an operator that reverses the truth or falsity of an interpretation. We argue that these results support both propositional and contextual accounts of negation present in the literature, suggesting that contextual factors are crucial for determining the kind of cognitive dynamics displayed. We conclude by drawing broader lessons about theories of cognition from the case of negation.     

Territorial gain dynamics regulates success in attacking sub-phases of team sports

Background and objective

Field invasion games, such as rugby union, can be conceptualised as dynamic social systems in which the agents continuously interact to contest ball possession and territorial gain. Accordingly, this study aimed to identify the collective system dynamics of rugby union phases-of-play near the try line by investigating whether ball displacement trajectory on the playing field provides insights on successful team performance.

Methods

Five rugby union matches were videotaped involving teams at a national league performance level. From these matches, 22 second phases-of-play were selected and digitized for analysis. The variable “distance gained” was investigated as a potential coordination variable describing functional coordination between players and teams. This variable concerned the distance between ball initial position and ball current position over time and was used to define the degree of territory gained by an attacking team.

Results

Analysis of distance gained dynamics in attacking sub-phases demonstrated the intermittent character of rugby union performers displacement trajectories on the playing field. Amplitude of ball movements was revealed as a distinguishing feature related to attacking effectiveness. Successful attacking phases displayed lower distances of positional retreat, with the maximum retreat distance achieved sooner in successful compared to unsuccessful phases-of-play. Autocorrelation and ApEn analyses suggested low system variability within time series data concerning both performance outcomes. However, evidence of less regularity and more complexity was found in unsuccessful phases-of-play.

Conclusion

Results suggested that distance gained dynamics manifests a characteristic collective behaviour pattern that captures the macroscopic functional order of multi-player attack–defence systems in team sports like rugby union.     

Alternative settings for liberal‐conservative exchange: Examining an undergraduate dialogue course

Given the polarization of the early 21st century political atmosphere in the U.S., intergroup dialogue has emerged as a unique alternative setting, with intentions of facilitating a more productive and thoughtful citizen engagement. Although cross‐partisan dialogue efforts are underway in community contexts, they have been slower to reach academic settings. This paper is an exploratory study of our own liberal‐conservative dialogue course at the University of Illinois–the first of its kind, to our knowledge. After describing basic features of the course, we identify themes from student journals and final evaluations suggesting both dialogue benefits and challenges. Finally, we discuss the growing literature around dialogue, questions of its long‐term impact, and larger potential barriers to participation in liberal‐conservative dialogue, specifically. Copyright © 2010 John Wiley & Sons, Ltd.     

Towards a “Sophisticated” Model of Belief Dynamics. Part I: The General Framework

It is well-known that classical models of belief are not realistic representations of human doxastic capacity; equally, models of actions involving beliefs, such as decisions based on beliefs, or changes of beliefs, suffer from a similar inaccuracies. In this paper, a general framework is presented which permits a more realistic modelling both of instantaneous states of belief, and of the operations involving them. This framework is motivated by some of the inadequacies of existing models, which it overcomes, whilst retaining technical rigour in so far as it relies on known, natural logical and mathematical notions. The companion paper (Towards a “sophisticated” model of belief dynamics. Part II) contains an application of this framework to the particular case of belief revision. Presented by Hannes Leitgeb     

Non-linear gaining in precision aiming: making Fitts' task a bit easier

The role of information in the processes underlying kinematic trajectory-formation was examined by manipulating the relation between effector space (movement of a hand-held stylus on a graphics tablet) and task space (movement of a cursor on a screen where targets were presented) in a precision aiming task with five different levels of task difficulty. Movement patterns were found to evolve as a function of the flow of information in task space, with participants (N = 13) producing more rapid and more fluent movements when the mapping between spaces included the softening-spring characteristics typical of behavioural patterns at higher levels of task difficulty. We conclude that the kinematic changes (movement time and pattern) observed when task difficulty increases result from informational influences. Information affects behavioural dynamics at the level of the parameters without affecting the underlying dynamical structure.