Jasnaja-Poljana en Astapowo Tolstoj als Wijsgeer

Tolstoj werd in 1828 te Jasnaja-Poliana geboren en stierf te Astapowo in 1910.     

Motion and color generate coactivation at postgrouping identification stages

Response times (RTs) were measured in a postgrouping visual identification task. Shapes composed of multiple elements were distinguished by color, motion, orientation, and spatial frequency alone or in pairwise conjunctions. The largest amount of redundancy gain, requiring coactivation as revealed by a race model analysis, was obtained with color-motion conjunctions. In contrast, RTs for a pregrouping detection task using the same target shape as in the identification task, distinguished by color, motion, or a conjunction of these features, showed no evidence for coactivation. The results provide psychophysical evidence for coactivation of color and motion signals in cortical regions specialized for grouping and object identification, as opposed to separate processing of these features in cortical area V1, believed to limit performance in visual search and pregrouping detection.     

Fatal Heyting Algebras and Forcing Persistent Sentences

Hamkins and L?we proved that the modal logic of forcing is S4.2. In this paper, we consider its modal companion, the intermediate logic KC and relate it to the fatal Heyting algebra H _ZFC of forcing persistent sentences. This Heyting algebra is equationally generic for the class of fatal Heyting algebras. Motivated by these results, we further analyse the class of fatal Heyting algebras.     

Nicolas Bourbaki and the concept of mathematical structure

In the present article two possible meanings of the term mathematical structure are discussed: a formal and a nonformal one. It is claimed that contemporary mathematics is structural only in the nonformal sense of the term. Bourbaki's definition of structure is presented as one among several attempts to elucidate the meaning of that nonformal idea by developing a formal theory which allegedly accounts for it. It is shown that Bourbaki's concept of structure was, from a mathematical point of view, a superfluous undertaking. This is done by analyzing the role played by the concept, in the first place, within Bourbaki's own mathematical output. Likewise, the interaction between Bourbaki's work and the first stages of category theory is analyzed, on the basis of both published texts and personal documents.Several persons have read and criticized earlier drafts of this paper. I thank them all for forcing me to formulate my ideas more simply and convincingly. Special thanks are due to Professors Pierre Cartier (Bures-sur-Yvette), Giorgio Israel (Rome), and Andrée C. Ehresmann (Amiens) for stimulating and illuminating conversations.     

Letter to the editor,Schools on Islands,a journal as a Ferry

In an electronic brainstorming session, experts and users of methods for multi-criteria decision analysis discussed editorial policies for a journal which is confronted with the conflicts between isolated schools of thought. The present paper describes the session and highlights how experts in multi-criteria decision analysis view the applications of their own methods on their own decision problems.     

Action and reaction elements as performance-modifying components of computer use in clinical psychology

Application of computerized equipment in psychodiagnosis and cognitive training entails novel methodical aspects which relate to design of operator and response controls as well as to the test configuration. Some of these aspects are discussed.     

A technique for chronic recording of systemic arterial blood pressure in the unrestrained rat

A technique is described for the chronic recording of systematic arterial blood pressure, respiration, and heart rate in the unrestrained rat. The surgical implantation and anchoring procedures described are compatible with the delivery of noxious electric shock and/or rewarding intracranial brain stimulation as reinforcement. Data on catheter patency are analyzed in 65 rats participating in a variety of experiments on the instrumental and classical conditioning of blood pressure responses. The results indicate that it is difficult to maintain satisfactory catheter performance beyond 2 weeks.