Sahlqvist's theorem for boolean algebras with operators with an application to cylindric algebras

For an arbitrary similarity type of Boolean Algebras with Operators we define a class ofSahlqvist identities. Sahlqvist identities have two important properties. First, a Sahlqvist identity is valid in a complex algebra if and only if the underlying relational atom structure satisfies a first-order condition which can be effectively read off from the syntactic form of the identity. Second, and as a consequence of the first property, Sahlqvist identities arecanonical, that is, their validity is preserved under taking canonical embedding algebras. Taken together, these properties imply that results about a Sahlqvist variety V van be obtained by reasoning in the elementary class of canonical structures of algebras in V.We give an example of this strategy in the variety of Cylindric Algebras: we show that an important identity calledHenkin's equation is equivalent to a simpler identity that uses only one variable. We give a conceptually simple proof by showing that the first-order correspondents of these two equations are equivalent over the class of cylindric atom structures.Presented byIstván Németi     

Constrained maximization reconsidered — An elaboration and critique of Gauthier's modelling of rational cooperation in a single prisoner's dilemma

Gauthier's argument for constrained maximization, presented inMorals by Agreement, is perfected by taking into account the possibility of accidental exploitation and discussing the limitations on the values of the parameters which measure the translucency of the actors. Gauthier's argument is nevertheless shown to be defective concerning the rationality of constrained maximization as a strategic choice. It can be argued that it applies only to a single actor entering a population of individuals who are themselves not rational actors but simple rule-followers. A proper analysis of the strategic choice situation involving two rational actors who confront each other shows that constrained maximization as the choice of both actors can only result under very demanding assumptions.     

Monocular discrimination of rigidly and nonrigidly moving objects

Wemeasured thresholds for the monocular discrimination of rigidly and nonrigidly moving objects defined by motion parallax. The retinal projections of rigidly moving objects are subject to certain constraints. By applying smooth 2-D transformations to the projections of rigidly moving objects, we created stimuli in which these constraints were affected. Thresholds for (generic) nonrigid transformations that in theory can be detected from rigid ones by processing pairs of views depended not only on the extent to which the rigidity constraints were affected, but also on the structure and the movement of the simulated object. Nonrigid transformations under which every three successive views had a rigid interpretation were not discriminable from rigid transformations, except in cases where the distortions were very large. Under the rigidity assumption, this would mean that a large class of nonrigidly moving objects is erroneously perceived as rigidly moving.     

CAMERA: A system for fast and reliable acquisition of multiple ethological records

CAMERA is a system for collecting and editing ethological data. The hardware and software enable easy coding of complex behavioral interactions from video recordings. It is especially designed to improve accuracy, reliability, and training standards in coding behavior. The system also supports several basic analyses of collected data. CAMERA operates with both North American and European video signals.     

Silence in Interdisciplinary Research Collaboration: Not Everything Said is Relevant,Not Everything Relevant is Said

Solving publicly important issues asks for the development of socio-technical approaches, which demands collaboration between researchers with different perspectives, values, and interests. In these complex interdisciplinary collaborations, the course of communication is of utmost importance, including the moments when people, consciously or not, keep silent. In 2012, an interdisciplinary group of water management engineers and scientists collaborated to explore how the university's separate water management research fields could fit better in today's socio-technical trends. Studying the interactional process revealed that during the collaboration many issues were not said by various parties at various times. Results show that, in particular, engineers and scientists stayed silent to secure group performance, to keep disagreements from surfacing, and manage conflicts of interest in the bargaining process. Although silence served various interactional functions, it also shaped the course of interaction in ways that were not intended, resulting in the development of a latent conflict. It is concluded that the concept of silence adds a relevant dimension to our understanding of interaction among engineers and scientists participating in interdisciplinary collaboration that is currently absent in existing literature on scientific collaboration.     

The multidimensional randomized response design: Estimating different aspects of the same sensitive behavior

The conventional randomized response design is unidimensional in the sense that it measures a single dimension of a sensitive attribute, like its prevalence, frequency, magnitude, or duration. This paper introduces a multidimensional design characterized by categorical questions that each measure a different aspect of the same sensitive attribute. The benefits of the multidimensional design are (i) a substantial gain in power and efficiency, and the potential to (ii) evaluate the goodness-of-fit of the model, and (iii) test hypotheses about evasive response biases in case of a misfit. The method is illustrated for a two-dimensional design measuring both the prevalence and the magnitude of social security fraud.     

Haptic mental rotation revisited: multiple reference frame dependence

The nature of reference frames involved in haptic spatial processing was addressed by means of a haptic mental rotation task. Participants assessed the parity of two objects located in various spatial locations by exploring them with different hand orientations. The resulting response times were fitted with a triangle wave function. Phase shifts were found to depend on the relation between the hands and the objects, and between the objects and the body. We rejected the possibility that a single reference frame drives spatial processing. Instead, we found evidence of multiple interacting reference frames with the hand-centered reference frame playing the dominant role. We propose that a weighted average of the allocentric, the hand-centered and the body-centered reference frames influences the haptic encoding of spatial information. In addition, we showed that previous results can be reinterpreted within the framework of multiple reference frames. This mechanism has proved to be ubiquitously present in haptic spatial processing.     

Introduction: The university revisited

Although universities are asked to play a role in the European knowledge society, the precise scope and meaning of this role is still under discussion. A major issue in this debate is the trend to adapt universities to economic needs and demands of society. In view of taking a critical stance against a one-sided economic interpretation of activities and functions of universities, their so-called “public” role is increasingly stressed in the debate as a crucial responsibility of universities that should not be marginalized and therefore deserves our attention. In this paper, which is the introduction to a special issue on the public role of the university, we want to stress the importance of addressing the question of “the role of universities in the Europe of knowledge” in an open way and thus, without prejudices against or in favour of possible answers. It is our contention that a critical view of what is happening in universities today cannot simply rely on authoritative ideas or principles that are vaguely reminiscent of our university traditions. Consequently, this introductory paper pleas for a firmer argumentative and a richer empirical basis that takes account of the fact that our background (horizon) has thoroughly changed in comparison to traditions that still implicitly inform our judgement of what universities can do, should do or should not do. Finally, we will discuss the way in which the articles collected in this issue are intended stimulating and supporting the debate on the public role of the university in Europe.