In this paper we outline the main tenets of the commognitive approach and we exemplify its application in studies that investigate the learning and teaching of mathematics at university level. Following an overview of such applications, we focus on three studies that explore fundamental discursive shifts often occurring in the early stages of studying Calculus. These shifts concern the lecturers' and students' communicative practices, routines of constructing mathematical objects and ways of resolving commognitive conflicts. We then propose that commognitive constructs such as subjectification can be deployed towards ‘scaling-up’ the hitherto fine-grained focus of commognitive analyses. Finally, we conclude with observing how the commognitive approach relates to constructs from other sociocultural approaches to research in university mathematics education, such as “legitimate peripheral participation” from the theory of Communities of Practice and “didactic contract” from the Theory of Didactic Situations

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Small off-road 4-stroke SI-engines have extraordinarily high pollutant emissions. These must be curtailed to comply with the new Swiss clean air act LRV 98. The Swiss environmental protection agency (BUWAL) investigated the state of the technology. The aim was a cleaner agricultural walk behind mower with a 1 OkW 4-stroke SI-engine. Two engine designs were compared: side-valve and OHV. A commercially available 3-way catalytic converter system substantially curtailed emissions: In the ISO 8178 G test-cycle-average, HC was minimized to 8% and CO to 5% of raw emissions. At part load points, the residual emission was < 1 %. Simultaneously, fuel consumption improved 10%. Using a special gasoline (Swiss standard SN 181 163), the aromatic hydrocarbons were curtailed, e.g. Benzene< 1%, and fuel consumption further improved. Those results were confirmed in field tests. The engine is approved for retrofitting. Disquieting are the high emissions of u ltrafine particulates: the catalytic converter only minimizes the volatile but not the solid particulates.

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