999 resultados para Von Neumann regularity
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In this thesis we consider systems of finitely many particles moving on paths given by a strong Markov process and undergoing branching and reproduction at random times. The branching rate of a particle, its number of offspring and their spatial distribution are allowed to depend on the particle's position and possibly on the configuration of coexisting particles. In addition there is immigration of new particles, with the rate of immigration and the distribution of immigrants possibly depending on the configuration of pre-existing particles as well. In the first two chapters of this work, we concentrate on the case that the joint motion of particles is governed by a diffusion with interacting components. The resulting process of particle configurations was studied by E. Löcherbach (2002, 2004) and is known as a branching diffusion with immigration (BDI). Chapter 1 contains a detailed introduction of the basic model assumptions, in particular an assumption of ergodicity which guarantees that the BDI process is positive Harris recurrent with finite invariant measure on the configuration space. This object and a closely related quantity, namely the invariant occupation measure on the single-particle space, are investigated in Chapter 2 where we study the problem of the existence of Lebesgue-densities with nice regularity properties. For example, it turns out that the existence of a continuous density for the invariant measure depends on the mechanism by which newborn particles are distributed in space, namely whether branching particles reproduce at their death position or their offspring are distributed according to an absolutely continuous transition kernel. In Chapter 3, we assume that the quantities defining the model depend only on the spatial position but not on the configuration of coexisting particles. In this framework (which was considered by Höpfner and Löcherbach (2005) in the special case that branching particles reproduce at their death position), the particle motions are independent, and we can allow for more general Markov processes instead of diffusions. The resulting configuration process is a branching Markov process in the sense introduced by Ikeda, Nagasawa and Watanabe (1968), complemented by an immigration mechanism. Generalizing results obtained by Höpfner and Löcherbach (2005), we give sufficient conditions for ergodicity in the sense of positive recurrence of the configuration process and finiteness of the invariant occupation measure in the case of general particle motions and offspring distributions.
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The rupture of intracranial aneurysms leads to subarachnoid hemorrhage, which is often associated with poor outcome. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the lack of candidate genes precludes identifying patients at risk by genetic analyses. We observed intracranial aneurysms in 2 patients with von Hippel-Lindau (VHL) disease and the known disease-causing mutation c.292T > C (p.Tyr98His) in the VHL tumor suppressor gene. This study investigates whether the VHL gene is a possible candidate gene for aneurysm formation.
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von Imm. Mor. Neumann
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von S. Neumann
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[S. Neumann]
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von Wilhelm Münz
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von Simon Neumann. Hrsg. vom Hauptbüro d. Jüd. Nationalfonds, Cöln
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Welsch (Projektbearbeiter): Kampfgedicht gegen den am 22. März 1848 nach England geflohenen Prinzen von Preußen, die Symbolfigur der bewaffneten Reaktion
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Welsch (Projektbearbeiter): Kritische Kommentierung der gewalttätigen Ausschreitungen von Teilen der Bevölkerung Charlottenburgs gegen die beabsichtigte Gründung eines Demokratischen Vereins am 20. August 1848: "Strafen müssen wir die Dorfdeibels, sonst wächst uns de Reakzion übern Kopp, und wir sind sammt unsre Freiheit belämmert." Bei den angesprochenen Todesfällen in Düsseldorf handelt es sich um einen "längere[n] Schußwechsel zwischen Bürgern und Soldaten, der erst durch ... Eingreifen der Bürgergarde beendet werden konnte" und der sich aus einer anläßlich eines Besuchs Friedrich Wilhelms IV. veranstalteten Katzenmusik entwickelte (14. August 1848). [Niemann, Dietmar: Die Revolution von 1848/49 in Düsseldorf; Düsseldorf 1993, S. 154/55] In der Form einer Unterhaltung der drei Berliner Bürger Neumann, Piesecke und Brennecke
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Welsch (Projektbearbeiter): Karikaturen auf den österreichischen Partikularismus sowie auf die Furcht der Repräsentanten des vormärzlichen Systems während des dritten Wiener Aufstandes (26. Mai 1848)
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Welsch (Projektbearbeiter): Karikaturen auf den Opportunismus vormärzlicher Funktionsträger sowie auf einen reaktionären Bezirkschef (laut handschriftlicher Eintragung ein gewisser "Director Carl". Möglicherweise der Theaterdirektor Carl Bernbrunn?)