Search results for "competition"
showing 10 items of 1409 documents
Pulsed-Resource Dynamics Constrain the Evolution of Predator-Prey Interactions
2011
Although temporal variability in the physical environment plays a major role in population fluctuations, little is known about how it drives the ecological and evolutionary dynamics of species interactions. We studied experimentally how extrinsic resource pulses affect evolutionary and ecological dynamics between the prey bacterium Serratia marcescens and the predatory protozoan Tetrahymena thermophila. Predation increased the frequency of defensive, nonpigmented prey types, which bore competitive costs in terms of reduced maximum growth rate, most in a constant-resource environment. Furthermore, the predator densities of the pulsed-resource environment regularly fluctuated above and below …
Intraguild predation and interference competition on the endangered dragonfly Aeshna viridis
2003
We examined the effects of intraguild predation (IGP) and interference competition on an endangered dragonfly, Aeshna viridis Eversm. (Odonata: Anisoptera). A. viridis is rare in Europe due to the decrease in suitable habitats harboring the macrophyte Stratiotes aloides L. Stratiotes plants are the principal oviposition substrate for A. viridis females and protect the larvae of A. viridis from fish predation. In our study lakes A. viridis larvae are sympatric with larvae of Aeshna grandis and Aeshna juncea. The susceptibility of A. viridis larvae to IGP by similar-sized larvae of A. grandis and A. juncea was tested in a laboratory predation experiment. Microhabitat use of A. viridis and A. …
Costly punishment prevails in intergroup conflict.
2011
Understanding how societies resolve conflicts between individual and common interests remains one of the most fundamental issues across disciplines. The observation that humans readily incur costs to sanction uncooperative individuals without tangible individual benefits has attracted considerable attention as a proximate cause as to why cooperative behaviours might evolve. However, the proliferation of individually costly punishment has been difficult to explain. Several studies over the last decade employing experimental designs with isolated groups have found clear evidence that the costs of punishment often nullify the benefits of increased cooperation, rendering the strong human tenden…
Competition for resources modulates cell-mediated immunity and stress hormone level in nestling collared doves (Streptopelia decaocto)
2008
International audience; Competitive stress imposed by hatching asynchrony may affect developmental trajectories of offsprings by regulating resource allocation between growth and other fitness-related traits. For instance, the down-regulation of immunity is a commonly observed phenomenon under stressful conditions. However, physiological mechanisms that regulate resources allocation to growth and immune functions in response to competition for resources, as well as inter-sexual differences in physiological strategies, are still poorly investigated. To partially fill this gap, we first conducted a descriptive study on chicks of the collared dove (Streptopelia decaocto), a species producing t…
Institutional Path Dependence in Competitive Dynamics: The Case of Paper Industries in Finland and the USA
2016
Prior research on competitive dynamics has failed to offer tools to understand distorted patterns of competition that emerge from distinct institutional and historical contexts. Our analysis suggests that a joint effect of institutional rules, governance structures, and shared cognition plays a pivotal role in firm-level competitive behavior and capability development. We show how globally significant market positions can result from specific institutional arrangements between firms and governments, especially if coupled with interfirm contractual commitments. Our results call for more attention to these interfirm commitments that are built on formal rules and governmental support, but whos…
Remote interspecies interactions: Improving humans and animals wellbeing through mobile playful spaces
2019
[EN] Play is an essential activity for both humans and animals as it provides stimulation and favors cognitive, physical and social development. This paper proposes a novel pervasive playful environment that allows hospitalized children to participate in remote interspecies play with dogs in a dog daycare facility, while it also allows the dogs to play by themselves with the pervasive system. The aim of this playful interactive space is to help improving both children¿s and animal¿s wellbeing and their relationships by means of technologically mediated play, while creating a solid knowledge base to define the future of pervasive interactive environments for animals.
Data offloading and task allocation for cloudlet-assisted ad hoc mobile clouds
2016
Nowadays, although the data processing capabilities of the modern mobile devices are developed in a fast speed, the resources are still limited in terms of processing capacity and battery lifetime. Some applications, in particular the computationally intensive ones, such as multimedia and gaming, often require more computational resources than a mobile device can afford. One way to address such a problem is that the mobile device can offload those tasks to the centralized cloud with data centers, the nearby cloudlet or ad hoc mobile cloud. In this paper, we propose a data offloading and task allocation scheme for a cloudlet-assisted ad hoc mobile cloud in which the master device (MD) who ha…
Online Pricing via Stackelberg and Incentive Games in a Micro-Grid
2019
This paper deals with the analysis and design of online pricing mechanisms in micro-grids. Two cases are studied in which the market layer is modeled as an open-loop and closed-loop dynamical system respectively. In the case of open-loop market dynamics, the price is generated as equilibrium price of a Stackelberg game with an incentive strategy. In such Stackelberg game, the leader is the energy supplier, the follower is the consumer, and the leader plays an incentive strategy. In the case of closed-loop market dynamics, the price is obtained as a function of the power supplied and the demand. A stability analysis is provided for both cases, which sheds light on the transient and steady-st…
On coincidence of feedback and global Stackelberg equilibria in a class of differential games
2021
This paper shows for a class of differential games that the global Stackelberg equilibrium (GSE) coincides with the feedback Stackelberg equilibrium (FSE), although the GSE assumes that the leader/regulator an- nounces at the initial time the regulatory instrument rule she will follow for the rest of the game, while in the FSE, the regulator at any time chooses the optimal level of the regulatory instrument rate. This coincidence is based on the fact that the FSE is calculated using dynamic programming what implies that although the regulator chooses the regulatory instrument rate level that maximizes social welfare, the first-order condition for the maximization of the right-hand side of t…
On the Coincidence of the Feedback Nash and Stackelberg Equilibria in Economic Applications of Differential Games
2002
In this paper the scope of the applicability of the Stackelberg equilibrium concept in differential games is investigated. Firstly, conditions for obtaining the coincidence between the Stackelberg and Nash equilibria are defined in terms of the instantaneous pay-off function and the state equation of the game. Secondly, it is showed that for a class of differential games with state-interdependence both equilibria are identical independently of the player being the leader of the game. A survey of different economic models shows that this coincidence is going to occur for a good number of economic applications of differential games. This result appears because of the continuous-time setting i…