The category of Urysohn spaces is not cowellpowered

AbstractIt is shown that the category of Urysohn spaces and continuous maps is not cowellpowered. To this end we will construct for each ordinal number β a Urysohn space Yβ with card (Yβ = ℵ0⋅ card (β) and a continuous map eβ:Q → Yβ from the rationals into Yβ. It turns out that eβ is an external monomorphism in the category of Hausdorff spaces and an epimorphism in the category of Urysohn spaces

Delannoy and tetrahedral numbers

summary:We establish an identity between Delannoy numbers and tetrahedral numbers of arbitrary dimension

Stilbene synthase from Scots pine (Pinus sylvestris)

AbstractStilbene synthases are named according to their substrate preferences. By this definition, enzymes preferring cinnamoyl-CoA are pinosylvin synthases, and proteins with a preference for phenylpropionyl-CoA are dihydropinosylvin synthases. We investigated the assignment of a stilbene synthase cloned from Scots pine (Pinus sylvestris) as dihydropinosylvin synthase and the proposal of an additional pinosylvin synthase [1992, Plant Mol. Biol. 18, 439–503]. The results show that the previous interpretation was misled by several unexpected factors. Firstly, we found that the substrate preference and the activity of the plant-specific protein expressed in E. coli was influenced by bacterial factors. This was reduced by improvement of the expression system, and the subsequent kinetic analysis revealed that cinnamoyl-CoA rather than phenylpropionyl-CoA is the preferred substrate of the cloned stilbene synthase. Secondly, mixing experiments showed that extracts from P. sylvestris contain factor(s) which selectively influenced the substrate preference, i.e. the activity was reduced with phenylpropionyl-CoA, but not with cinnamoyl-CoA. This explained the apparent differences between plant extracts and the cloned enzyme expressed in E. coli. Taken together, the results indicate that the cloned enzyme is a pinosylvin synthase, and there is no evidence for a second stilbene synthase. This study cautions that factors in the natural and in new hosts may complicate the functional identification of cloned sequences

"Barrierefreiheit" und Heterogenität - eine erweiterte Perspektive auf Zugänglichkeit und Nutzung Neuer Medien

Das politische Konzept der Barrierefreiheit zielt auf die Gestaltung Neuer Medien – insbesondere des Internets. Es ist eine Reaktion auf deren Bedeutungszuwachs sowie auf die Wahrnehmung eines anhaltenden, konstruktionsbedingten Ausschlusses von deren Nutzung, vor allem von bestimmten Gruppe Behinderter. Dies gilt in vergleichbarer Weise aber ebenso für weitere soziale Gruppen. Für das Ziel einer realen Nutzung dieses Mediums durch alle ist es sinnvoll, es als sozialen Raum zu interpretieren, in dem bestimmte Bedingungen zur Teilhabe herrschen und der sozial differenzierende Wirkungen hat

Cinnamate 4-hydroxylase from Catharanthus roseus and a strategy for the functional expression of plant cytochrome P450 proteins as translational fusions with P450 reductase in Escherichia coli

AbstractA PCR-based approach was used to isolate cDNAs for cinnamate 4-hydroxylase (C4H) from Catharanthus roseus cell cultures. The protein shared 75.9% identity with C4H from other plants and the transcription was induced under various stress conditions. The cloned protein was used to investigate the functional expression of plant P450/P450-reductase fusions in E. coli. Fusions containing a modified N-terminal membrane anchor were located in the membrane and possessed C4H activity without solubilization or addition of other factors. The results indicate that the fusion protein strategy provides a useful tool to analyze the activities encoded in the rapidly increasing number of plant P450 sequences of uncertain or unknown function. We also discuss critical elements of the strategy: the choice of the E. coli host strain, the N-terminal membrane anchor, and the conditions for protein expression

From Siberia with love or angst in the city? On the idea of merging research projects in Novosibirsk and co-teaching in Hamburg and Berlin

Angst in the City is the title that the authors of these lines chose for a joint research project and seminar looking into expressions of emotion and social exclusion in diverse urban environments. The title serves as a shorthand for apprehensive feelings that individuals or groups perceive when physically or imaginarily finding themselves in certain spaces in the fabric of the city that they inhabit. The concept of fear will be discussed in more detail below (pp. 7-9). This article has four goals: first, to lay out how this research cooperation on the perception of urban space came into being; second, how it proceeded and what initial results emerged from it; and third, how the research generated the idea of jointly organized teaching. Students who participated in Angst in the City conducted small research projects on their own in Hamburg, Schwerin and Berlin, and four of their essays have been adopted for publication in this special issue of Ethnoscripts. To prepare the conceptual ground for these four contributions is the fourth goal of this article. It closes with a remark on how the students’ projects feed back into our own plans for further research

From Siberia with love or angst in the city? On the idea of merging research projects in Novosibirsk and co-teaching in Hamburg and Berlin

Angst in the City is the title that the authors of these lines chose for a joint research project and seminar looking into expressions of emotion and social exclusion in diverse urban environments. The title serves as a shorthand for apprehensive feelings that individuals or groups perceive when physically or imaginarily finding themselves in certain spaces in the fabric of the city that they inhabit. The concept of fear will be discussed in more detail below (pp. 7-9). This article has four goals: first, to lay out how this research cooperation on the perception of urban space came into being; second, how it proceeded and what initial results emerged from it; and third, how the research generated the idea of jointly organized teaching. Students who participated in Angst in the City conducted small research projects on their own in Hamburg, Schwerin and Berlin, and four of their essays have been adopted for publication in this special issue of Ethnoscripts. To prepare the conceptual ground for these four contributions is the fourth goal of this article. It closes with a remark on how the students’ projects feed back into our own plans for further research

From Siberia with Love or Angst in the City? On the Idea of Merging Research Projects in Novosibirsk and Co-Teaching in Hamburg and Berlin

Angst in the City is the title that the authors of these lines chose for a jointresearch project and seminar looking into expressions of emotion and socialexclusion in diverse urban environments. The title serves as a shorthand forapprehensive feelings that individuals or groups perceive when physically orimaginarily finding themselves in certain spaces in the fabric of the city thatthey inhabit. The concept of fear will be discussed in more detail below (pp.7-9). This article has four goals: first, to lay out how this research cooperation on the perception of urban space came into being; second, how it proceeded and what initial results emerged from it; and third, how the research generated the idea of jointly organized teaching. Students who participated in Angst in the City conducted small research projects on their own in Hamburg, Schwerin and Berlin, and four of their essays have been adopted for publication in this special issue of Ethnoscripts. To prepare the conceptual ground for these four contributions is the fourth goal of this article. It closes with a remark on how the students’ projects feed back into our own plans for further research

From Siberia with Love or Angst in the City? On the Idea of Merging Research Projects in Novosibirsk and Co-Teaching in Hamburg and Berlin

Angst in the City is the title that the authors of these lines chose for a jointresearch project and seminar looking into expressions of emotion and socialexclusion in diverse urban environments. The title serves as a shorthand forapprehensive feelings that individuals or groups perceive when physically orimaginarily finding themselves in certain spaces in the fabric of the city thatthey inhabit. The concept of fear will be discussed in more detail below (pp.7-9). This article has four goals: first, to lay out how this research cooperation on the perception of urban space came into being; second, how it proceeded and what initial results emerged from it; and third, how the research generated the idea of jointly organized teaching. Students who participated in Angst in the City conducted small research projects on their own in Hamburg, Schwerin and Berlin, and four of their essays have been adopted for publication in this special issue of Ethnoscripts. To prepare the conceptual ground for these four contributions is the fourth goal of this article. It closes with a remark on how the students’ projects feed back into our own plans for further research