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Rapport van de Animal Sciences Group over het welzijn van dieren in circussen in Nederland. Er zijn gedragsobservaties en klinische inspecties uitgevoerd in 6 circussen in 2008. Er is gesproken met ervaringsdeskundigen uit de circuswereld en hun percepties van dierenwelzijn zijn vastgesteld. Tevens zijn 2 internationale wetenschappers gevraagd om de belangrijkste welzijnsrisico's voor dieren in circussen in kaart te brengen. Resultaten van dit onderzoek vormen de basis voor politieke besluitvorming en beleidsontwikkeling rond het gebruik van dieren in circussen

The aim of the present study was to evaluate the suitability of cellulose-based scaffolds coated with pure sodium silicate gel and sodium silicate gels accumulated with different concentrations of the bisphosphonate pamidronate as scaffolds for attachment, proliferation and differentiation of human fetal osteoblasts (hFOB 1.19). Human osteoblasts were cultured in vitro for a period up to 14 days on different cellulose scaffolds. Unmodified and sodium silicate coated cellulose scaffolds were used as control. Two surface-coated modifications of cellulose were applied. The scaffolds were coated in a modified two-step dip coating process with pure sodium silicate gel and pamidronate enriched sodium silicate gel, respectively. In order to investigate the influence of the pamidronate, concentrations of 0.667 mg Na-pamidronate/ml sodium silicate solution, 0.333 mg Na-pamidronate/ml sodium silicate solution and 3.33 × 10-3 mg Na-pamidronate/ml sodium silicate solution were used for the coating process. Cell proliferation, vitality and attachment were examined by means of cell counting, WST-1 test, fluorescence and scanning electron microscopy. The relative grade of differentiation of hFOB cells was examined by using quantitative real-time polymerase chain reaction (qRT-PCR) analysis for the gene expression of alkaline phosphatase and osteocalcin. Proliferation and differentiation of human osteoblasts was enhanced by the sodium silicate coatings accumulated with pamidronate compared to pure sodium silicate coatings. There was a reciprocal correlation of vitality with the concentration of pamidronate. The highest vitality was found on surfaces with the lowest pamidronate accumulation. Alkaline phosphatase, an early differentiation marker, was overexpressed after 7 days in cells on all pamidronate-containing surfaces (up to 350% compared to untreated cellulose). Osteocalcin, a late differentiation marker, was overexpressed after 14 days in cells on all coated surfaces (up to 300,000% compared to untreated cellulose). The results indicate that due to the modified coating procedure a homogeneous coating and thus, an enhancement of cell attachment and subsequent cellular functions can be achieved. Low concentrations of pamidronate seem to have a relevant effect on cell proliferation and vitality and, therefore, can be recommended for the improvement of the properties of a biomaterial. © 2008 Elsevier B.V. All rights reserved.

In human societies, cooperative behaviour in public goods interactions is usually enforced through institutions that impose sanctions on free-riders. Many experiments on public goods games have shown that in the absence of such institutions, individuals are often willing to punish defectors, even at a cost to themselves, effectively taking the law into their own hands. Theoretical models confirm that social norms prescribing the punishment of deviant behaviour are stable: once established, they prevent invasion by dissident minorities. But how can such costly punishing behaviour gain a foothold in the population? A surprisingly simple model shows that if individuals have the option to stand aside and abstain from the public goods interaction, this paves the way for the emergence and establishment of cooperative behaviour based on the punishment of defectors. Thus the freedom to withdraw from the public enterprise leads to a self-enforcing prosocial norm. Paradoxically, the option of individual autarky may be an important step for the emergence of institutions punishing the non-cooperation of their members. Conversely, public goods interactions which are obligatory rather than voluntary are unlikely to gain a foothold in the population.

Mit Hilfe eines zweigeteilten Versuchsaufbaus wurde die Eignung unterschiedlicher Genotypen für die ökologische Schweinefleischerzeugung untersucht. Im Modul 1 wurden zur Bestimmung des Gewebewachstums (mit Hilfe der Magnet Resonanz Tomographie) und der Fleischqualität insgesamt 90 Tiere der Genetiken Bundeshybridzuchtprogramm (BHZP), Schwäbisch-Hällisches Schwein (SH), Piétrain x SH (PixSH) and Duroc x Deutsche Landrasse (DuxDL) ökologisch gemästet. Die SH-Schweine zeigten von Mastbeginn an das stärkste Fettgewebewachstum und das geringste Muskelwachstum. Die DuxDL-Tiere besaßen die höchsten mittleren Tageszunahmen. PixSH- und BHZP-Tiere besaßen die höchsten Muskelfleischanteile. Die PixSH-Tiere hatten zwar den niedrigsten pH45-Wert und die höchsten Tropfsaftverluste im großen Rückenmuskel 24 Stunden nach der Schlachtung, trotzdem waren keine Qualitätsabweichungen zu beanstanden. Im Modul 2 wurden insgesamt 682 Tiere der Genetiken BHZP, SH, Angler Sattelschwein (AS), PixSH, PixAS, Pi x Deutsches Edelschwein (PixDE) und DuxDL ökologisch und konventionell gehalten und gefüttert. Tageszunahme, Futterverwertung, Muskelfleischanteil, Fettmaße und Fleischqualität aller Schweine wurden durch ein lineares Model mit den fixen Effekten Umwelt (ökologisch, konventionell), Genetik, Geschlecht sowie Interaktion von Genetik and Umwelt geprüft. Obwohl signifikante Interaktionen zwischen Genotyp und Umwelt für die meisten Merkmale (außer Fleischqualität) gefunden wurden, konnten aber keine Unterschiede in der Rangierung zwischen den Genetiken innerhalb der beiden Umwelten beobachtet werden. So schnitten die unter konventionellen Haltungs- und Fütterungsbedingungen leistungsstärksten modernen Genetiken auch unter Ökobedingungen am besten ab. Es wird geschlussfolgert, dass bei vergleichbaren Vermarktungszielen die ökologische Schweinefleischerzeugung keine speziellen Zuchtprogramme benötigt.

This survey deals with indirect reciprocity, i.e., with the possibility that altruistic acts are returned, not by the recipient, but by a third party. After briefly sketching how this problem is dealt with in classical game theory, we describe recent work on the assessment on interactions, and the evolutionary stability of strategies for indirect reciprocation. All stable strategies ( the 'leading eight') distinguish between justified and non-justified defections, and therefore are based on non-costly punishment. Next we consider the replicator dynamics of populations consisting of defectors, discriminators and undiscriminating altruists. We stress that errors can destabilise cooperation for strategies not distinguishing justified from unjustified defections, but that a fixed number of rounds, or the assumption of an individual's social network growing with age, can lead to cooperation based on a stable mixture of undiscriminating altruists and of discriminators who do not distinguish between justified and unjustified defection. We describe previous work using agent-based simulations for 'binary-score' and 'full score' models. Finally, we survey the recent results on experiments with the indirect reciprocation game.

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This paper presents, in a series of simple diagrams, concise results about the replicator dynamics of direct and indirect reciprocity. We consider repeated interactions between donors and recipients, and analyse the relationship between three basic strategies for the donor: unconditional cooperation, all-out defection, and conditional cooperation. In other words, we investigate the competition of discriminating and undiscriminating altruists with defectors. Discriminators and defectors form a bistable community, and hence a population of discriminators cannot be invaded by defectors. But unconditional altruists can invade a discriminating population and soften it up for a subsequent invasion by defectors. The resulting dynamics exhibits various forms of rock-paper-scissors cycles and depends in subtle ways on noise, in the form of errors in implementation. The probability for another round (in the case of direct reciprocity), and information about the co-player (in the case of indirect reciprocity), add further elements to the ecology of reciprocation.

The evolution of cooperation within sizeable groups of non-related humans offers many challenges for our understanding. Current research has highlighted two factors boosting cooperation in public goods interactions, namely costly punishment of defectors, and the option to defer from the joint enterprise. A recent modeling approach has suggested that the autarctic option acts as a catalyzer for the ultimate fixation of altruistic punishment. We present an alternative, more micro-economically based model which yields a bistable outcome instead. Evolutionary dynamics can either lead to a Nash equilibrium of punishing and non-punishing cooperators, or to an oscillating state without punishers.

Whether one-shot interactions can stably sustain mutual cooperation if they are based on a minimal form of reputation building has been the subject of considerable debate. We show by mathematical modeling that the answer is positive if we assume an individual's social network evolves in time. In this case, a stable mixture of discriminating and undiscriminating altruists can be proof against invasion by defectors. This sheds light on current discussions about the merits of different types of moral assessment, an issue where theoretical arguments and experimental findings seem at odds.Unexpectedly, our approach also relates to the proverbial observation that people tend to become more tightfisted with age.

Ever since image-based models of indirect reciprocity were introduced, the relative merits of scoring vs. standing have been discussed to find out how important it is to differentiate between justified and non-justified defections. This is analogous to the question whether punishment can sustain cooperation even when it is costly. We show that an answer to this question can depend on details of the model, for instance concerning the probability distribution of the number of the number of interactions experienced per player. We use extensive individual-based simulations to compare scoring, standing and other forms of assessing defections, and show that other forms of indirect reciprocation can robustly sustain cooperation. By most standards, standing is better than scoring, but nevertheless scoring is able to sustain cooperation in the presence of errors. The model presented here is based on the specifications: each player has a personal list of images of all co-players, a specific way of judging an observed situation, and a specific strategy to decide whether to cooperate or not.

The notion of a fitness landscape has permeated the analysis of evolutionary processes for more than 60 years. Introduced by Sewall Wright for discussing biological evolution and speciation, the concept has recently been transferred to the study of abstract genotypes of various evolutionary algorithms. The features of high-dimentional fitness landscapes can vary to a high degree, and the question by which means they can be described has turned out to be a challenging problem. Even though some statistics have been suggested for this purpose and are already well-analyzed, presently discussed statistics do not seem appropriate for obtaining sufficiently accurate predictions of evolutionary dynamics at the level of fitness. In this study, an analysis of three different types of fitness landscapes is presented. I introduce a new correlation measure, and show by comparing the actual evolutionary waiting times to those predicted when only taking into account the correlation statistics, that these statistics seem to capture salient information of the underlying fitness landscapes. Based on one-dimensional correlation statistics, very accurate predictions of evolutionary waiting times are achieved for the fitness landscape of the Travelling Salesman Problem and NKp landscapes with low degree of neutrality. Both for the NKp landscapes with high neutrality and RSF landscapes, which in a similar way involve large-scale neutrality, high-dimensional correlation statistics provide enough information to estimate evolutionary waiting times. Finally I present an approach towards analytic descriptions of evolutionary dynamics for the analyzed fitness of low neutrality.

Fitness landscapes underlie the dynamics of evolutionary processes and are a key concept of evolutionary theory. Recent research on molecular folding and on evolutionary algorithms has demonstrated that such landscapes are also important for understanding problems of chemistry and of combinatorial optimization. In these cases free energy or cost functions are used instead of biological fitness functions defined on genotypes. However, the image of a three dimensional landscape with many peaks and valleys turns out to be misleading. Genotypes tend to differ in numerous characteristics, resulting in multidimensional fitness landscapes. Properties of these landscapes are very different from those of low dimensional ones. The main intention of this study is to investigate how these features affect the duration of adaptive walks on such landscapes. For this purpose we focus on the Traveling Salesman Problem (TSP), which amounts to finding the shortest tour visiting a given set of locations. By comparing theoretical predictions for the duration of adaptive walks to the actual waiting times observed for an evolutionary algorithm we demonstrate that a sufficiently fine-grained correlation matrix succeeds in capturing essential structural features of the TSP fitness landscape. To test the performance of correlation-based predictions for a class of fitness landscapes with varying degree of neutrality, we have analyzed evolutionary waiting times on NKp fitness landscapes. We show that for low degrees of neutrality, correlation statistics again prove to be an excellent basis for predicting waiting times, while for very high degrees of neutrality, a population's drift along neutral networks turns out to require incorporation of additional information on network topologies.