The characterization of second-order type isomorphisms is a purely syntactical problem that we propose to study under the enlightenment of game semantics. We study this question in the case of second-order λμ-calculus, which can be seen as an extension of system F to classical logic, and for which we define a categorical framework: control hyperdoctrines.Our game model of λμ-calculus is based on polymorphic arenas which evolve during the play. We show that type isomorphisms coincide with the “equality” on arenas associated (...) with types. Finally we deduce the equational characterization of type isomorphisms from this equality. We also recover from the same model Roberto Di Cosmo’s characterization of type isomorphisms for system F.This approach leads to a geometrical comprehension on the question of second-order type isomorphisms, which can be easily extended to some other polymorphic calculi including additional programming features. (shrink)

Centrosomes are the main microtubule organizing centers in animal cells. In particular during embryogenesis, they ensure faithful spindle formation and proper cell divisions. As metazoan centrosomes are eliminated during oogenesis, they have to be reassembled upon fertilization. Most metazoans use the sperm centrioles as templates for new centrosome biogenesis while the egg's cytoplasm re-prepares all components for on-going centrosome duplication in rapidly dividing embryonic cells. We discuss our knowledge and the experimental challenges to analyze zygotic centrosome reformation, which requires genetic (...) experiments to enable scrutinizing respective male and female contributions. Male and female knockout animals and mRNA injection to mimic maternal expression of centrosomal proteins could point a way to the systematic molecular dissection of the process. The most recent data suggest that timely expression of centrosome components in oocytes is the key to zygotic centrosome reformation that uses male sperm as coordinators for de novo centrosome production. Centrosome reformation at fertilization is essential for metazoan development. It requires a complicated interplay of sperm centrioles and the cytoplasm of the oocyte, which has eliminated its centrioles during oogenesis. The male centrioles launch centrosome duplication using female centrosome proteins for the first metazoan cell divisions. (shrink)

​„Plessner in Wiesbaden“ schildert das Leben und Werk eines Philosophen und Soziologen (1892-1985), der das 20. Jahrhundert durchlebt, durchlitten und durchdacht hat. Ausgangspunkt ist das jüngere Interesse seiner Geburts- und Heimatstadt an dem großen Sohn der Stadt, das sich in der Stiftung eines „Wiesbadener Plessner Preises“ manifestiert. Damit wird ein Schlüsseldenker der modernen Philosophischen Anthropologie gewürdigt. Neben einigen Beiträgen zu Plessner in Wiesbaden enthält der Band auch Beiträge zu Plessners anderen Lebens- und Wirkungsstationen wie Heidelberg, Erlangen, Köln, Groningen, Göttingen, New (...) York, Zürich. In diesen Stationen und ihren Facetten wird deutlich, warum Helmuth Plessner einer der maßgebenden Intellektuellen der Bundesrepublik Deutschland werden konnte.​. (shrink)

Bd. 1. Yoga für Anfänger.-- Bd. 8. Yoga als Lebenskraft und Lebenshilfe.

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be (...) preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)