Brain drain: A communitarian response to Brock and Blake

The problem of brain drain, the movement of skilled citizens of developing countries to developed ones, arises largely because of seriously unequal life prospects in different countries. Hence, there is something profoundly wrong with the brain drain, something that calls for a moral response. Brock and Blake offer such a response by debating the ethical rights and responsibilities of skilled professionals, and of the societies in which they live, from the perspective of moral liberalism. The aim of my paper is to develop a response to some of their arguments from the perspective of moral communitarianism, with particular reference to the work of one of its classical proponents in African philosophy, Kwame Gyekye.     

Authentic leadership influences on organisational commitment in a South African state hospital

This study investigated the influence of authentic leadership (AL) on employee organisational commitment (OC) in a South African state hospital. A convenience sample of 222 employees (female = 81%; black = 82%) completed the Authentic Leadership Questionnaire on their perceptions of AL behaviours among their leaders; namely self-awareness, relational transparency, internalised moral perspective, and balanced processing. The employees also completed the Organisational Commitment Questionnaire to self-report on their own OC; namely affective, continuance, and normative commitment. Data were analysed utilising regression analysis to predict employees’ self-reported OC from perceived AL behaviours. Findings suggest AL scores to predict OC scores as well as the OC dimensions of continuance and normative commitment. AL scores did not predict affective commitment. Employees whose leaders apply AL may be able to retain employees through increased OC.     

Edge detection based on Hodgkin–Huxley neuron model simulation

In this paper, we propose a spiking neural network model for edge detection in images. The proposed model is biologically inspired by the mechanisms employed by natural vision systems, more specifically by the biologically fulfilled function of simple cells of the human primary visual cortex that are selective for orientation. Several aspects are studied in this model according to three characteristics: feedforward spiking neural structure; conductance-based model of the Hodgkin–Huxley neuron and Gabor receptive fields structure. A visualized map is generated using the firing rate of neurons representing the orientation map of the visual cortex area. We have simulated the proposed model on different images. Successful computer simulation results are obtained. For comparison, we have chosen five methods for edge detection. We finally evaluate and compare the performances of our model toward contour detection using a public dataset of natural images with associated contour ground truths. Experimental results show the ability and high performance of the proposed network model.     

Sensory load incurs conceptual processing costs

Theories of grounded cognition propose that modal simulations underlie cognitive representation of concepts [Barsalou, L. W. (1999). Perceptual symbol systems. Behavioral and Brain Sciences, 22(4), 577-660; Barsalou, L. W. (2008). Grounded cognition. Annual Review of Psychology, 59, 617-645]. Based on recent evidence of modality-specific resources in perception, we hypothesized that verifying properties of concepts encoded in different modalities are hindered more by perceptual short-term memory load to the same versus different sensory modality as that used to process the property. We manipulated load to visual and auditory modalities by having participants store one or three items in short-term memory during property verification. In the high (but not low) load condition, property verification took longer when the property (e.g., yellow) involved the same modality as that used by the memory load (e.g., pictures). Interestingly, similar interference effects were obtained on the conceptual verification and on the memory task. These findings provide direct support for the view that conceptual processing relies on simulation in modality-specific systems.     

Aggressor and victim perspective-related differences in perceived legitimacy of aggression in soccer

The purpose of this role-playing study was to explore the perceived legitimacy of aggression in soccer as a function of perspective-related differences (aggressor vs victim) and type of aggression (instrumental vs hostile). 120 soccer players watched videotaped aggressive interactions in soccer and took the perspective of the actors (aggressor then victim or the reverse). Then they rated the legitimacy of each aggressive behavior depending on its ultimate goal (instrumental then hostile or the reverse). When participants adopted the aggressor perspective, they perceived instrumental aggression as more legitimate than hostile aggression. In contrast, when participants took the perspective of the victim, no significant difference was found regardless of the type of aggression. The discussion focussed on implications and consequences of such divergences in aggressive sport situations.     

The modular structure of physical theories

Any advanced theory of physics contains modules defined as essential components that are themselves theories with different domains of application. Different kinds of modules can be distinguished according to the way in which they fit in the symbolic and interpretive apparatus of a theory. The number and kind of the modules of a given theory vary as the theory evolves in time. The relative stability of modules and the variability of their insertion in other theories play a vital role in the application, comparison, construction, and communication of theories. Modularity conveys some global unity to physics through the sharing of modules by diverse theories. This alternative to rigid hierarchies and holistic totalities permits a dynamical, plastic, and symbiotic approach to physical theory.     

Aging of the planning process: the role of executive functioning

This study tested whether the aging of executive functioning is linked to the decline in planning performance. Participants were divided into three groups: group 1 composed of 15 adults with a mean age of 22.7 years, group 2 composed of 15 adults with a mean age of 68.1 years and group 3 composed of 16 adults with a mean age of 78.75 years. Each participant took tests for shifting, inhibition, updating and processing speed. Planning was evaluated by the Tower of Hanoi task with 3 and 4 disks. Analyses of variance showed a main age effect on the many executive functioning and planning measures assessed. Analyses of regression indicated that combined processing speed and shifting accounted for 58.33% of performance on the 3-disk version, while processing speed accounted for only 36.86% of performance on the 4-disk version. These results are discussed in relation to two levels of the planning process: formulation and execution.     

Resilience and hypothalamic-pituitary-adrenal axis reactivity under acute stress in young men

The present study examined the relationship between resilience (measured using the Resilience Scale for Adults) and hypothalamic-pituitary-adrenal (HPA) axis reactivity. We examined the subjective and cortisol responses of 28 healthy young men to an acute stressor (public speech task). Eight saliva samples were collected in order to obtain the response curve (anticipation, reactivity, recuperation) for each subject. ANOVA indicated that highly resilient individuals tended to display less mood deterioration than less resilient individuals (marginal p(time x group interaction) = 0.075). They also revealed that the former tended to secrete less cortisol overall than the latter during the experiment (marginal p(main group effect) = 0.087) but this effect was not uniform across time (p(time x group interaction) = 0.029). Additional analyses performed to identify the source of this interaction revealed that resilience moderates cortisol secretion in anticipation of the stressor (i.e. highly resilient individuals secreted less cortisol than less resilient ones, p = 0.05) but that it is not conductive to lower HPA reactivity amidst stress (i.e. there was no difference between groups in the increase in cortisol secretion from baseline to peak). The recovery slopes were likewise not statistically different. The implications of these findings regarding health are discussed.     

Visual objects can potentiate a grasping neural simulation which interferes with manual response execution

Previous studies on visuomotor priming have provided insufficient information to determine whether the reach-to-grasp potentiation of a non-target object produces a specific effect during response execution. In order to answer this question, subjects were instructed to reach and grasp a response device with either a power or a precision grip, depending on whether the stimulus they saw was empty or full. Stimuli consisted of containers (graspable with either a power or a precision grip), with non-graspable stimuli added as a control condition (geometrical shapes). The image of the non-target object was removed during the execution phase. Results demonstrate slower execution responses related to motor incompatibility, though conversely, no faster responses with motor compatibility. Moreover, any visuomotor priming effect required that the container be displayed during response execution. These data suggest that during response execution, motor incompatibility produces a disruptive effect likely due to competition between two cerebral events: motor control of the actual response execution and visual object reach-to-grasp neural simulation.     

A Faradayan Principle for Selecting Classical Field Theories

Faraday’s field concept presupposes that field stresses should share the axial symmetry of the lines of force. In the present article, the field dynamics is similarly required to depend only on field properties that can be tested through the motion of test‐particles. Precise expressions of this ‘Faradayan’ principle in field‐theoretical language are shown to severely restrict the form of classical field theories. In particular, static forces must obey the inverse square law in a linear approximation. Within a Minkowskian and Lagrangian framework, the Faradayan principle automatically leads to Maxwell’s theory of electromagnetism and to Einstein’s theory of gravitation, without appeal to the equivalence principle. A comparison is drawn between this, Feynman’s, and Einstein’s way to arrive at general relativity.