Food webs under stress : The structure, stability and functioning of stressed soil food webs

Verhoef, H.A. [Promotor]Gestel, C.A.M. van [Copromotor

Affective Match: Leader Emotional Displays, Follower Positive Affect, and Follower Performance

Leader emotions may play an important role in leadership effectiveness. Extending this earlier research on leader emotional displays and leadership effectiveness, we propose that the “affective match†between follower positive affect (PA) and leaders’ emotional displays moderates the effectiveness of leader emotional displays. Leader display of emotions has more positive effects on follower behavior if the match between the valence of leader emotion and follower PA is strong rather than weak. Support for this hypothesis was found in two experiments. The congruency between leader emotional displays and follower PA determined follower task performance and extra-role compliance. Results from the second experiment indicated that this effect is due to the affective aspects of leader behavior and not to the valence of the content of the message.Emotions;Leadership Effectiveness;Positive Affect

Leader Affective Displays and Attributions of Charisma: The Role of Arousal

Research suggests that leader displays of positive affect are conducive to attributions of charisma. We qualify and extend this conclusion by arguing that this mainly holds for displays of positive affect that are associated with high levels of arousal. Results of a scenario experiment and a survey support this hypothesis, and show that besides the transfer of positive feelings per se, it is the transfer of arousal that mediates the relationship between leader affective displays and attributions of charisma.Arousal;Charisma;Leader Affect;Positive Feelings

Community gardens: A natural way to wellbeing

Community gardens provide social, economic and environmental benefits to local urban communities. These include individual and collective social wellbeing, access to cheap, nutritious food and improved functioning of the local ecology. Although regarded by some as a neutral project to organise a community around, community gardening is still highly political. When planned, organised and run by local people and located centrally in the community, (particularly disadvantaged communities) these green spaces offer multiple health benefits that prevent disease and promote wellbeing, a sense of citizen control and social capital. Most indicators suggest that community gardening movement has enjoyed varied success in building healthier Sydney communities. However the intrinsic effects of this low cost, low-tech community process is hard to compare and measure. Challenges include security of tenure, establishing appropriate policy and planning guidelines with local councils and departments, ensuring active and full participation of those community groups 'at risk' and developing persuasive evaluation systems to meet these challenges. It is suggested that community gardens reflect the wider social, cultural, structural elements in the society as well as the human processes that ultimately enable or restrict healthy living

Overanticoagulation on coumarin anticoagulants

Most of the extensive research on oral anticoagulant therapy has focussed on its pharmacological- and biochemical action, prothrombin time calibration, optimal therapeutic intensity and hemorrhagic complications. However, whlle the risks of overanticoagulation are clear, its treatment and determinants have received little attention. Therefore, the aim of this thesis was to study aspects of overanticoagulation on coumarin anticoagulants among outpatients of an anticoagulation clinic. Overanticoagulation was defined as an INR:>6.0, since at this INR-value the risk of hemorrhage sharply increases (28, 41). Chapter 2 relates to the treatment of overanticoagulation and describes the course of the INR in response to oral vitamin K1 in overanticoagulated patients. Chapter 3 concerns the incidence of and risk factors for overanticoagulation and includes five studies. Chapter 3.1 focusses on characteristics of antic

Red Queen Evolution by Cycles of Evolutionary Branching and Extinction

We use the theory of adaptive dynamics to construct and analyse a generic example of cycling evolution with alternating levels of polymorphism. A monomorphic population evolves towards larger trait values until it reaches a so-called evolutionary branching point. Disruptive selection at the branching point splits the population into two strategies. In the dimorphic population the strategies undergo parallel coevolution towards smaller trait values. Finally one of the two strategies goes extinct, and the remaining single strategy evolves upwards again to the branching point. The reversal of the direction of evolution is brought about by the changing level of polymorphism. Extinction is deterministic, i.e., it occurs inevitably and always at the same trait values; which of the two strategies goes extinct is, however, random. The present model is discussed in relation to other mechanisms for evolutionary cycles involving branching and extinction

Modelling locational decision making of firms using multidimensional fuzzy decision tables : an illustration

No abstract

Dynamics of Bragg Grating Solitons In Coupled Bragg Gratings With Dispersive Reflectivity

We study dynamics of Bragg grating solitons in a system of linearly coupled Bragg gratings with Kerr nonlinearity. The effects of dispersive reflectivity on the behaviour of solitons in the system are investigated by solving the coupled mode equations numerically. Gap solitons, are found to exist throughout the bandgap of the structure. The system supports two types of symmetric and asymmetric solitons that can have any velocities from zero to the speed of light in the medium. At given soliton parameters a critical coupling coefficient is found above which only symmetric solitons exist. Below the critical point however, both types of gap solitons may exist at the same time. Linear forms of coupled mode equations are solved analytically. The results are in excellent agreement with the gap soliton tails. Also, using the linear analysis a condition is found for the solitons to have sidelobes in their tails. Stability of solitons are investigated using systematic simulations. Generally, when dispersive reflectivity is zero, asymmetric solitons are stable for ω≥0. While with increase of dispersive reflectivity the stable region expands into the negative frequencies. Symmetric solitons on the other hand are found to be stable where they exist on their own. Interactions of quiescent gap solitons in the model are studied numerically. The outcomes generally depend on the initial separation (Δx) and phase difference. However, when the dispersive reflectivity is small, Δx-dependence is very weak. Interactions are found to result in a number of outcomes including merger into a single quiescent soliton, destruction, formation of a bound state that eventually breaks up into two separating solitons, formation of two moving and one quiescent solitons, and repulsion. The most interesting outcomes of the collisions of counter-propagating in-phase moving solitons are merger and 2→3 transformation. On the contrary, out-of-phase collisions generally result in the repulsion of the pulses