Learning to Reach Agreement in a Continuous Ultimatum Game

It is well-known that acting in an individually rational manner, according to the principles of classical game theory, may lead to sub-optimal solutions in a class of problems named social dilemmas. In contrast, humans generally do not have much difficulty with social dilemmas, as they are able to balance personal benefit and group benefit. As agents in multi-agent systems are regularly confronted with social dilemmas, for instance in tasks such as resource allocation, these agents may benefit from the inclusion of mechanisms thought to facilitate human fairness. Although many of such mechanisms have already been implemented in a multi-agent systems context, their application is usually limited to rather abstract social dilemmas with a discrete set of available strategies (usually two). Given that many real-world examples of social dilemmas are actually continuous in nature, we extend this previous work to more general dilemmas, in which agents operate in a continuous strategy space. The social dilemma under study here is the well-known Ultimatum Game, in which an optimal solution is achieved if agents agree on a common strategy. We investigate whether a scale-free interaction network facilitates agents to reach agreement, especially in the presence of fixed-strategy agents that represent a desired (e.g. human) outcome. Moreover, we study the influence of rewiring in the interaction network. The agents are equipped with continuous-action learning automata and play a large number of random pairwise games in order to establish a common strategy. From our experiments, we may conclude that results obtained in discrete-strategy games can be generalized to continuous-strategy games to a certain extent: a scale-free interaction network structure allows agents to achieve agreement on a common strategy, and rewiring in the interaction network greatly enhances the agents ability to reach agreement. However, it also becomes clear that some alternative mechanisms, such as reputation and volunteering, have many subtleties involved and do not have convincing beneficial effects in the continuous case

Zephyr bioharness in de praktijk

Een te hoge fysieke belasting bij (top)sporters en brandweerpersoneel kan op de lange termijn leiden tot overbelasting. In het revalidatie proces kan het de terugkeer naar het veld vertragen. Daarom is het nauwkeurig monitoren van de fysieke belasting erg belangrijk. Het Zephyr BioHarness lijkt hiervoor een geschikt instrument omdat het in staat is om verschillende fysiologische variabelen tegelijkertijd te meten. In dit rapport worden vier projecten besproken waarin de fysieke belasting gemeten is met het Zephyr BioHarness: (I) effect van veldgrootte op de belasting bij jonge talentvolle voetballers van FC Groningen, (II) overeenkomsten in belasting tussen oefeningen/sporten en uitrukken bij de professionele brandweer, (III) overeenkomsten tussen geplande belasting van fysiotherapeuten met daadwerkelijk belasting bij veldrevalidatie na een blessure (IV) validatie van Zensorium Tinké

Metacognition in psychotic disorders

Being able to think about one’s own thoughts and feelings (metacognition) is often difficult for persons with a psychotic disorder. These difficulties have a negative influence on the (interpersonal) functioning. In the first part of this dissertation, we discuss different definitions of metacognitions which are used and the associated treatments, the link between metacognitive abilities and work experience, and risk of violence. In the second part of this dissertation we discuss our research into the effectiveness of a new psychotherapy aimed at metacognitive capacity in psychosis. First, we report our findings in the treatment of a single patient (case study), then a group of patients with whom we found encouraging results (pilot study), and finally a large study into the effectiveness of 40 sessions of this treatment in 35 patients compared to 35 patients who did not receive any treatment. Our results are modestly encouraging: immediately after treatment we find no differences between the groups; both groups had improved. In the control group, however, this effect disappears after 6 months, while the group which had received therapy continued to improve on metacognitive capacity

Multiple Interactions Between Cancer Cells and the Tumor Microenvironment Modulate TRAIL Signaling:Implications for TRAIL Receptor Targeted Therapy

Tumor necrosis factor (TNF) related apoptosis-inducing ligand (TRAIL) signaling is far more complex than initially anticipated and can lead to either anti- or protumorigenic effects, hampering the successful clinical use of therapeutic TRAIL receptor agonists. Cell autonomous resistance mechanisms have been identified in addition to paracrine factors that can modulate apoptosis sensitivity. The tumor microenvironment (TME), consisting of cellular and non-cellular components, is a source for multiple signals that are able to modulate TRAIL signaling in tumor and stromal cells. Particularly immune effector cells, also part of the TME, employ the TRAIL/TRAIL-R system whereby cell surface expressed TRAIL can activate apoptosis via TRAIL receptors on tumor cells, which is part of tumor immune surveillance. In this review we aim to dissect the impact of the TME on signaling induced by endogenous and exogenous/therapeutic TRAIL, thereby distinguishing different components of the TME such as immune effector cells, neutrophils, macrophages, and non-hematopoietic stromal cells. In addition, also non-cellular biochemical and biophysical properties of the TME are considered including mechanical stress, acidity, hypoxia, and glucose deprivation. Available literature thus far indicates that tumor-TME interactions are complex and often bidirectional leading to tumor-enhancing or tumor-reducing effects in a tumor model- and tumor type-dependent fashion. Multiple signals originating from different components of the TME simultaneously affect TRAIL receptor signaling. We conclude that in order to unleash the full clinical potential of TRAIL receptor agonists it will be necessary to increase our understanding of the contribution of different TME components on outcome of therapeutic TRAIL receptor activation in order to identify the most critical mechanism responsible for resistance, allowing the design of effective combination treatments