Developmental changes in lateralized inhibition of symmetric movements in children with and without Developmental Coordination Disorder.

The present study investigates developmental changes in selective inhibition of symmetric movements with a lateralized switching task from bimanual to unimanual tapping in typically developing (TD) children and with Developmental Coordination Disorder (DCD) from 7 to 10 years old. Twelve right-handed TD children and twelve gender-matched children with DCD and probable DCD produce a motor switching task in which they have (1) to synchronize with the beat of an auditory metronome to produce bimanual symmetrical tapping and (2) to selectively inhibit their left finger's tapping while continuing their right finger's tapping and conversely. We assess (1) the development of the capacity to inhibit the stopping finger (number of supplementary taps after the stopping instruction) and (2) the development of the capacity to maintain the continuing finger (changes in the mean tempo and its variability for the continuing finger's tapping) and (3) the evolution of performance through trials. Results indicate that (1) TD children present an age-related increase in the capacity to inhibit and to maintain the left finger's tapping, (2) DCD exhibits persistent difficulties to inhibit the left finger's tapping, and (3) both groups improve their capacity to inhibit the left finger's movements through trials. In conclusion, the lateralized switching task provides a simple and fine tool to reveal differences in selective inhibition of symmetric movements in TD children and children with DCD. More theoretically, the specific improvement in selective inhibition of the left finger suggests a progressive development of inter-hemispheric communication during typical development that is absent or delayed in children with DCD.

Bargaining failures and merger policy

In this paper we study the optimal ex-ante merger policy in a model where merger proposals are the result of strategic bargaining among alternative candidates. We allow for firm asymmetries and, in particular, we emphasize the fact that potential synergies generated by a merger may vary substantially depending on the identity of the participating firms. The model demonstrates that, under some circumstances, relatively inefficient mergers may take place. That is, a particular merger may materialize despite the existence of an alternative merger capable of generating higher social surplus and even higher profits. Such bargaining failures have important implications for the ex-ante optimal merger policy. We show that a more stringent policy than the ex-post optimal reduces the scope of these bargaining failures and raises expected social surplus. We use a bargaining model that is flexible, in the sense that its strategic structure does not place any exogenous restriction on the endogenous likelihood of feasible mergers.

Influence of structural heterogeneities and of large scale topography on imbricate gravitational rock slope failures: New insights from 3-D physical modeling and geomorphological analysis

Initial topography and inherited structural discontinuities are known to play a dominant role in rock slope stability. Previous 2-D physical modeling results demonstrated that even if few preexisting fractures are activated/propagated during gravitational failure all of those heterogeneities had a great influence on mobilized volume and its kinematics. The question we address in the present study is to determine if such a result is also observed in 3-D. As in 2-D previous models we examine geologically stable model configuration, based upon the well documented landslide at Randa, Switzerland. The 3-D models consisted of a homogeneous material in which several fracture zones were introduced in order to study simplified but realistic configurations of discontinuities (e.g. based on natural example rather than a parametric study). Results showed that the type of gravitational failure (deep-seated landslide or sequential failure) and resulting slope morphology evolution are the result of the interplay of initial topography and inherited preexisting fractures (orientation and density). The three main results are i) the initial topography exerts a strong control on gravitational slope failure. Indeed in each tested configuration (even in the isotropic one without fractures) the model is affected by a rock slide, ii) the number of simulated fracture sets greatly influences the volume mobilized and its kinematics, and iii) the failure zone involved in the 1991 event is smaller than the results produced by the analog modeling. This failure may indicate that the zone mobilized in 1991 is potentially only a part of a larger deep-seated landslide and/or wider deep seated gravitational slope deformation.

Stochastic stability and the evolution of coordination in spatially structured populations.

Animals can often coordinate their actions to achieve mutually beneficial outcomes. However, this can result in a social dilemma when uncertainty about the behavior of partners creates multiple fitness peaks. Strategies that minimize risk ("risk dominant") instead of maximizing reward ("payoff dominant") are favored in economic models when individuals learn behaviors that increase their payoffs. Specifically, such strategies are shown to be "stochastically stable" (a refinement of evolutionary stability). Here, we extend the notion of stochastic stability to biological models of continuous phenotypes at a mutation-selection-drift balance. This allows us to make a unique prediction for long-term evolution in games with multiple equilibria. We show how genetic relatedness due to limited dispersal and scaled to account for local competition can crucially affect the stochastically-stable outcome of coordination games. We find that positive relatedness (weak local competition) increases the chance the payoff dominant strategy is stochastically stable, even when it is not risk dominant. Conversely, negative relatedness (strong local competition) increases the chance that strategies evolve that are neither payoff nor risk dominant. Extending our results to large multiplayer coordination games we find that negative relatedness can create competition so extreme that the game effectively changes to a hawk-dove game and a stochastically stable polymorphism between the alternative strategies evolves. These results demonstrate the usefulness of stochastic stability in characterizing long-term evolution of continuous phenotypes: the outcomes of multiplayer games can be reduced to the generic equilibria of two-player games and the effect of spatial structure can be analyzed readily.

Coordination of Transit and School Busing in Iowa, Final Report, December 2003

The 2003 Iowa General Assembly asked the Iowa Department of Transportation (Iowa DOT) to conduct a study of Iowa public policy regarding coordination of public transit services and school transportation. This report describes the efficiencies that may be obtained by coordinating transit management and maintenance systems in the areas of school transportation, public transit, and other forms of public transportation. The Center for Transportation Research and Education (CTRE) at Iowa State University studied these issues and prepared this report for the Iowa DOT.

Report on Special Investigation of the Central Point Coordination for Calhoun and Pocahontas Counties for the Period July 1, 1998 through May 31, 2004

Report on a Special Investigation of the Central Point Coordination for Calhoun and Pocahontas Counties.

Business Organization and Coordination in Marketing Specialty Hogs: A Comparative Analysis of Two Firms from Iowa, November 2005

We study business organization and coordination of specialty-market hog production using a comparative analysis of two Iowa pork niche-marketing firms. We describe and analyze each firms management of five key organizational challenges: planning and logistics, quality assurance, process verication and management of �credence attributes,� business structure, and profit sharing. Although each firm is engaged in essentially the same activity, there are substantial differences across the two firms in the way production and marketing are coordinated. These differences are partly explained by the relative size and age of each firm, thus highlighting the importance of organizational evolution in agricultural markets, but are also partly the result of a formal organizational separation between marketing and production activities in one of the firm.

Nine-month-olds' triangular interactive strategies with their parents' couple in low-coordination families: A descriptive study

Observing infants in triadic situations has revealed their triangular competence; namely, their ability to interact with both parents by simultaneously sharing their attention and affects with them. Infants' triangular interaction is linked with the coparenting unit's degree of coordination; in high-coordination (HC) families, parents act as a team in relation to the child, thus drawing clear and flexible boundaries with them; in low-coordination (LC) families, parents either avoid direct interaction with each other and include the child in their unit or join together against the child and exclude him or her, thus drawing inconsistent boundaries with the child. We explored the interactive strategies of LC 9-month-olds (n = 15) with those of their parents, comparing them with HC parents (n = 23) in two conditions: playing with both parents at the same time and witnessing their parents' dialogue. LC infants' affects were less positive; they addressed fewer positive triangular bids to their parents and tended to use a less triangular interactive mode. Thus, LC infants had fewer opportunities than did HC infants to acquire skills necessary for coping with triangular interaction. L'observation de nourrissons dans des situations triadiques a révélé leur compétence triangulaire, c'est-à-dire la capacité à interagir avec les deux parents en partageant simultanément leur attention et leurs affects avec eux. L'interaction triangulaire des nourrissons est liée au degré de coordination de l'unité de coparentage. Dans les familles à coordination élevée (abrégé HC en anglais, CE en français), les parents agissent en relation à l'enfant en tant qu'équipe, et établissent donc des limites claires et flexibles avec les enfants. Dans les familles à coordination faible (abrégé LC en anglais, CF en français), les parents évitent soit l'interaction directe l'un avec l'autre et incluent l'enfant dans leur unité, ou bien ils se liguent contre l'enfant et l'excluent, établissant donc des limites contradictoires avec l'enfant. Nous explorons les stratégies interactives de bébés de 9 mois CF avec celle de leurs parents, en les comparant avec des parents CE (N = 23) dans deux conditions: le jeu avec les deux parents au même moment et l'observation du dialogue des parents. Les affects des bébés CF étaient moins positifs. Les bébés se tournaient moins triangulairement vers leurs parents et avaient tendance à utiliser un mode interactif moins triangulaire. Les bébés CF avaient donc moins de chances que les bébés CE d'acquérir les compétences nécessaires pour faire face avec une interaction triangulaire.

Coordination pattern variability provides functional adaptations to constraints in swimming performance.

In a biophysical approach to the study of swimming performance (blending biomechanics and bioenergetics), inter-limb coordination is typically considered and analysed to improve propulsion and propelling efficiency. In this approach, 'opposition' or 'continuous' patterns of inter-limb coordination, where continuity between propulsive actions occurs, are promoted in the acquisition of expertise. Indeed a 'continuous' pattern theoretically minimizes intra-cyclic speed variations of the centre of mass. Consequently, it may also minimize the energy cost of locomotion. However, in skilled swimming performance there is a need to strike a delicate balance between inter-limb coordination pattern stability and variability, suggesting the absence of an 'ideal' pattern of coordination toward which all swimmers must converge or seek to imitate. Instead, an ecological dynamics framework advocates that there is an intertwined relationship between the specific intentions, perceptions and actions of individual swimmers, which constrains this relationship between coordination pattern stability and variability. This perspective explains how behaviours emerge from a set of interacting constraints, which each swimmer has to satisfy in order to achieve specific task performance goals and produce particular task outcomes. This overview updates understanding on inter-limb coordination in swimming to analyse the relationship between coordination variability and stability in relation to interacting constraints (related to task, environment and organism) that swimmers may encounter during training and performance.