A growing body of empirical research suggests many animal species are capable of social learning and even have cultural behavioral traditions. Social learning has implications for community ecology; changes in behavior can lead to changes in inter- and intra-specific interactions. The paper explores possible implications of social learning for ecological community dynamics. Four arguments are made: social learning can result in locally-specific ecological relationships; socially-mediated, locally-specific ecological relationships can have localized indirect interspecific population effects; the involvement of multiple co-existing species (...) in socially learned, locally-specific behavior has the potential to create community-wide effects, including varying levels of stability and instability; and social learning can create new intra- and inter-specific selection pressures on local taxa, potentially resulting in rapid evolution. Implications of all four arguments are discussed in relation to community ecology research and modeling. (shrink)

Magnetic resonance imaging (MRI) can provide a number of measurements relevant to sport-related concussion (SRC) symptoms; however, most studies to date have used a single MRI modality and whole-brain exploratory analyses in attempts to localize concussion injury. This has resulted in highly variable findings across studies due to wide ranging symptomology, severity and nature of injury within studies. A multimodal MRI, symptom-guided region-of-interest (ROI) approach is likely to yield more consistent results. The functions of the cerebellum and basal ganglia transcend (...) many common concussion symptoms, and thus these regions, plus the white matter tracts that connect or project from them, constitute plausible ROIs for MRI analysis. We performed diffusion tensor imaging (DTI), resting-state functional MRI, quantitative susceptibility mapping (QSM), and cerebral blood flow (CBF) imaging using arterial spin labeling (ASL), in youth aged 12-18 years following SRC, with a focus on the cerebellum, basal ganglia and white matter tracts. Compared to controls similar in age, sex and sport (N= 20), recent SRC youth (N= 29; MRI at 8 ± 3 days post injury) exhibited increased susceptibility in the cerebellum (p= 0.032), decreased functional connectivity between the caudate and each of the pallidum (p= 0.035) and thalamus (p= 0.021), and decreased diffusivity in the mid-posterior corpus callosum (p< 0.038); no changes were observed in recovered asymptomatic youth (N= 16; 41 ± 16 days post injury). For recent symptomatic-only SRC youth (N= 24), symptom severity was associated with increased susceptibility in the superior cerebellar peduncles (p= 0.011) and reduced activity in the cerebellum (p= 0.013). Fewer days between injury and MRI were associated with reduced cerebellar-parietal functional connectivity (p< 0.014), reduced activity of the pallidum (p= 0.002), increased CBF in the caudate (p= 0.005), and reduced diffusivity in the central corpus callosum (p< 0.05). Youth SRC is associated with acute cerebellar inflammation accompanied by reduced cerebellar activity and cerebellar-parietal connectivity, as well as structural changes of the middle regions of the corpus callosum accompanied by functional changes of the caudate, all of which resolve with recovery. Early MRI post-injury is important to establish objective MRI-based indicators for concussion diagnosis, recovery assessment and prediction of outcome. (shrink)

The present work investigates whether the hemispheric processing of both verbal and emotional stimuli, studied by means of a dichotic listening task, differs between normal high and low dissociators as assessed by the Dissociative Experiences Scale . Development, reliability and validity of a dissociation scale. Journal of Nervous and Mental Disease, 174, 727–735). Two groups of subjects , participated in the experiment. The task consisted in identifying both verbal and emotional stimulus-targets, respectively, on successive sessions. Reaction time and response accuracy (...) were registered and analysed using ANOVA . The interaction between stimuli , channel , and dissociation level reached statistical significance in terms of accuracy measures = 4.75; p < .05). Both high and low dissociators exhibited the expected right ear advantage on verbal targets. On the other hand, whereas low dissociators exhibited the expected left ear advantage on emotional targets, high dissociators failed to follow this typical pattern of hemispheric asymmetry: both hemispheres exhibited similar performances. These results confirm the hypothesis that dissociation is related to changes in hemispheric processing, specifically of emotional information. (shrink)

RésuméLa psychanalyse se pose comme savoir quant à certains aspects de l'esprit humain et comme instrument pour y apporter des changements. II y a relativement peu de travaux consacrés à la structure de ce savoir ou aux modalités ?action de cet instrument. Ce travail se propose ?examiner brièvement ce qui dans l'oeuvre du pionnier de la psychanalyse – Sigmund Freud –, ou à partir ?elle, permet ?entrevoir les réponses qui pourraient être apportées à de telles questions.

We generalize the concept of a cooperative non-transferable utility game by introducing a socially structured game. In a socially structured game every coalition of players can organize themselves according to one or more internal organizations to generate payoffs. Each admissible internal organization on a coalition yields a set of payoffs attainable by the members of this coalition. The strengths of the players within an internal organization depend on the structure of the internal organization and are represented by an exogenously given (...) power vector. More powerful players have the power to take away payoffs of the less powerful players as long as those latter players are not able to guarantee their payoffs by forming a different internal organization within some coalition in which they have more power.We introduce the socially stable core as a solution concept that contains those payoffs that are both stable in an economic sense, i.e., belong to the core of the underlying cooperative game, and stable in a social sense, i.e., payoffs are sustained by a collection of internal organizations of coalitions for which power is distributed over all players in a balanced way. The socially stable core is a subset and therefore a refinement of the core. We show by means of examples that in many cases the socially stable core is a very small subset of the core.We will state conditions for which the socially stable core is non-empty. In order to derive this result, we formulate a new intersection theorem that generalizes the KKMS intersection theorem. We also discuss the relationship between social stability and the wellknown concept of balancedness for NTU-games, a sufficient condition for non-emptiness of the core. In particular we give an example of a socially structured game that satisfies social stability and therefore has a non-empty core, but whose induced NTU-game does not satisfy balancedness in the general sense of Billera. (shrink)

Selon un lieu commun, la géographie médiévale se réduirait à une vaste parenthèse ouverte entre la fin du siècle d'or de l'Empire romain et la renaissance des grandes découvertes du XV° siècle. Mais quelle réalité s'agit-il de représenter ? Car toute représentation est tributaire, non seulement de conceptions particulières, mais aussi de moyens techniques qui ont présidé à son élaboration. Dans cet article, le lien entre la réalité et ses images, qui organise habituellement l'histoire de la cartographie, sera relâché au (...) bénéfice des représentations comme un système de signes appelé à prendre sens dans une production et une réception . L'enquête médiévale révèle l'attention des contemporains à la complexité de ces relations et représentations.According to common understanding, medieval geography would be reduced to a vast parenthesis, open between the end of the golden century of the Roman Empire and the renaissance of the great discoveries of the 15th century. But what is the reality being represented ?For every representation is tributary, not only of particular conceptions, but also of the technical capacities that preceded its elaboration. In this article, the connection between reality and its images, which habitually organized the history of cartography, will be set aside for the benefit of representations as a system, of signs called to have meaning in a production and a reception . This medieval inquiry reveals the attention that contemporaries have given to the complexity of its relations and representations. (shrink)

Originally published 1968, the book examines the ways in which the definitions of education held by different groups with power have changed since 1800 and traces which social institutions exercised the preponderant influence on the growth of the English educational system during the seminal period in which the state system was founded and grew to its present position. Especial attention is given to the influence of the ideologies of the various social classes, to the growing demands of the economy on (...) the educational system and to changes in the structure of the family. (shrink)