Synthesis and Reactivity of Tricarbonyl(1-ethoxy-carbonyl-2-methylpentadienyl)iron(1+) Cation

The title cation was prepared in two steps from the known (ethyl 3-methyl-6-oxo-2,4-hexadienoate)Fe(CO)3. Reation of the cation with NaBH3CN, methyl cuprate, phthalimide, water, PPh3, or malonate anions gave predominantly the products from nucleophilic attack at the C5 pentadienyl carbon

The evolution of body size, horn shape and social behaviour in crown Antilopini - an ancestral character state analysis

The earliest known bovids, commonly placed in the genus Eotragus, are small species with short straight horns that are located above the orbits. Among living bovids there are several species that show a similar horn morphology. These dwarf antelopes were historically united in the group „Neotragini“, which is now known to be a polyphyletic assemblage. The species in the genera Ourebia, Raphicerus, Dorcatragus, Madoqua, Oreotragus, Nesotragus, and Neotragus are scattered across the bovid phylogenetic tree. Nevertheless, the shared similarities, not only in body size and horn length but also in their social organisation, are interpreted to represent shared plesiomorphic traits that were present in the most recent common ancestor of Antilopinae. Most dwarf antelopes are closely related to gazelles and their allies, placed in the taxon Antilopini. Using a species level phylogeny of this group, I reconstructed ancestral states of several characters for the most recent common ancestor of Antilopini. While the results for the reconstruction of ancestral social organisation of the dwarf species are inconclusive, the small body size and short horns of Ourebia, Raphicerus, Dorcatragus, and Madoqua are most likely derived traits. The habitus of the ancestor of Antilopini was probably very similar to modern gazelles, consistent with the placement of the earliest fossil Antilopini in the genus Gazella

Unternehmen setzen Standards

Wenn global agierende Unternehmen einen konkreten Beitrag zu einer nachhaltigen Entwicklung leisten wollen, muß sich ihr Handeln weltweit als umwelt- und sozialverträglich erweisen. Zum Unternehmenskonzept der BSH Bosch und Siemens Hausgeräte GmbH gehört es daher, hier bereits etablierte Umweltschutzstandards auch im Ausland einzuhalten und so zu deren Verbreitung auf den globalen Märkten beizutragen

Enhancements of Discretization Approaches for Non-Convex Mixed-Integer Quadratically Constraint Quadratic Programming

We study mixed-integer programming (MIP) relaxation techniques for the solution of non-convex mixed-integer quadratically constrained quadratic programs (MIQCQPs). We present two MIP relaxation methods for non-convex continuous variable products that enhance existing approaches. One is based on a separable reformulation, while the other extends the well-known MIP relaxation normalized multiparametric disaggregation technique (NMDT). In addition, we introduce a logarithmic MIP relaxation for univariate quadratic terms, called sawtooth relaxation, based on [4]. We combine the latter with the separable reformulation to derive MIP relaxations of MIQCQPs. We provide a comprehensive theoretical analysis of these techniques, and perform a broad computational study to demonstrate the effectiveness of the enhanced MIP relaxations in terms producing tight dual bounds for MIQCQP