A simple graph is reflexive if its second largest eigenvalue λ2 is less than or equal to 2. A graph is a cactus, or a treelike graph, if any pair of its cycles (circuits) has at most one common vertex. For a lot of cactuses the property λ2 ≤ 2 can be tested by identifying and deleting a single cut-vetex (Theorem 1). if this theorem cannot be applied to a connected reflexive cactus and if all it...

Durch den andauernden Preisverfall von CD-Rohlingen und CD-Brennern bzw. durch die zunehmende Verbreitung von Internettauschbörsen sah sich die Musikindustrie gezwungen, effektive Kopierschutzverfahren für Audio-CDs zu entwickeln. Auf der einen Seite stellen sich nun Urheber die Frage nach der Wirksamkeit der Verfahren. Auf der anderen Seite befürchten Käufer eine Einschränkung der legalen Nutz...

The Drosophila NF-κB protein Dorsal is expressed at the larval neuromuscular junction, where its expression appears unrelated to known Dorsal functions in embryonic patterning and innate immunity. Using confocal microscopy with domain-specific antisera, we demonstrate that larval muscle expresses only the B isoform of Dorsal, which arises by intron retention. We find that Dorsal B interacts wit...

An Euclidean greedy embedding of a graph is a straight-line embedding in the plane, such that for every pair of vertices s and t, the vertex s has a neighbor v with smaller distance to t than s. This drawing style is motivated by greedy geometric routing in wireless sensor networks. A Christmas cactus is a connected graph in which every two simple cycles have at most one vertex in common and in...

In the world of cactus & succulent (C S) literature, books suitable for children to young adults have been a little-recognised resource. This paper is first systematic treatment this subject. 116 C S were identified and analysed. Of these, 82% are educational, or non-fiction; 18% fiction 15% based around poetry, with 10% activity colouring books. The most productive place publication US which a...