Learn More
Group selection theory has a history of controversy. After a period of being in disrepute, models of group selection have regained some ground, but not without a renewed debate over their importance as a theoretical tool. In this paper I offer a simple framework for models of the evolution of altruism and cooperation that allows us to see how and to what(More)
It is often suggested that any group selection model can be recast in terms of inclusive fitness. A standard reference to support that claim is "'Quantitative genetics, inclusive fitness, and group selection" by Queller (1992) in the American Naturalist 139 (3), 540-558. In that paper the Price equation is used for the derivation of this claim. Instead of a(More)
BACKGROUND This study aimed to obtain an answer for the question: Are ergonomic guidelines applied in the operating room and what are the consequences? METHODS A total of 1,292 questionnaires were sent by email or handed out to surgeons and residents. The subjects worked mainly in Europe, performing laparoscopic and/or thoracoscopic procedures within the(More)
The well-known replicator dynamics is usually applied to 2-player games and random matching. Here we allow for games with n players, and for population structures other than random matching. This more general application leads to a version of the replicator dynamics of which the standard 2-player, well-mixed version is a special case, and which allows us to(More)
In multi-player games n individuals interact in any one encounter and derive a payoff from that interaction. We assume that individuals adopt one of two strategies, and we consider symmetric games, which means the payoff depends only on the number of players using either strategy, but not on any particular configuration of the encounter. On the cycle we(More)
We analyse simulations reported in "The co-evolution of individual behaviors and social institutions" by Bowles et al., 2003 in the Journal of Theoretical Biology 223, 135-147, and begin with distinguishing two types of group selection models. The literature does not provide different names for them, but they are shown to be fundamentally different and have(More)
Natural selection works against cooperation unless a specific mechanism is at work. These mechanisms are typically studied in isolation. Here we look at the interaction between two such mechanisms: tag recognition and population structure. If cooperators can recognize each other, and only cooperate among themselves, then they can invade defectors. This is(More)
Fitness is the central concept in evolutionary theory. It measures a phenotype's ability to survive and reproduce. There are different ways to represent this measure: Malthusian fitness and Wrightian fitness. One can go back and forth between the two, but when we characterize model properties or interpret data, it can be important to distinguish between(More)
BACKGROUND The aim of this study is to gain insight into the problems encountered by the medical team related to products used for minimally invasive surgery. METHODS An inventory was made of the problems encountered during 12 endoscopic operations performed in one city hospital (Eindhoven, the Netherlands). After the observation, a questionnaire was(More)
BACKGROUND The aim of this study is to create new ergonomic guidelines for the design of laparoscopic needle holders. METHODS An ergonomic literature study, observations in the operating room, handle-shaft angle measurements, and anthropometric data were used to compile new ergonomic criteria, specified to the function of a laparoscopic needle holder.(More)