Recombination induced hypergraphs: A new approach to mutation-recombination isomorphism

Natural selection acts on genetic variation that comes from two principal sources: mutation and recombination. Because of the inherent differences between mutation and recombination, it is often assumed that they are qualitatively different ways to explore the genotype space. In this paper a new way of constructing recombination spaces is introduced and the topological features of the resulting hypergraphs are analyzed. It is shown that types which are neighbors in the point mutation space are also neighbors in the recombination space, i.e., mutation and recombination spaces are homomorphic. This implies that the shapes of the fitness functions explored by mutation and recombination are similar. However, the potential of one- and two-point recombination operators to explore the fitness landscape may differ dramatically from uniform recombination operators or mutation operators because of the limited number of recombinant types they can produce. © 1996 John Wiley & Sons, Inc.     

Silicon-Modified Carbohydrate Surfactants I: Synthesis of Siloxanyl Moieties Containing Straight-chained Glycosides and Amides

New siloxanyl-modified carbohydrate surfactants of the amide and glycoside type have been synthesized by coupling between defined as well as higher-molecular-weight siloxanes and carbohydrate structures via spacers of different lengths and hydrophilic power. Linear and branched monohydrogen di-, tri-, tetra- and penta-siloxanes and polyhydrogen siloxanes as well as mono- and di-saccharide lactone structures have been found to be good starting materials for the synthesis of amides, often in quantitative yield, whereas glycosides had to be prepared in low-yield multistep sequences including protection/deprotection steps. Selected strategies were applied to polysiloxanes yielding quantitatively a broad variety of carbohydrate-modified comb-like structures. The new substances were characterized by means of ¹³C NMR spectroscopy, GC, capillary GC, GC–MS coupling and elemental analysis.     

Photoemission core level and satellite study of TixRu1−xoxide layers

Combined photoemission core level and satellite structure investigations of pyrolytic titanium-rich Ti_xRu_1−x-oxide layers (0.90 ≦ x ≦ 0.97) and RuO₂ layers on titanium are used to gain structural and compositional information about these electro-catalytically active surfaces. By means of this method deviations from stoichiometry, the formation of carbon interstitials and the growth of anatase by ruthenium loss could be pointed out.     

Mechanism of the oxygen-stimulated deactivation of RuyTi1−y-oxide overlayers on Ti studied by XPS,SEM and electrochemical techniques

By means of wet oxygen exposure the stability of RTO anodes has been observed. The deactivation is due to ruthenium loss via unstable higher surface oxides in a long time regime. As follows after uneffective subsurface annealing procedure the catalytic durability is reduced drastically by erosion stimulated increasing ruthenium loss of inhomogeneous active layer surfaces.     

Crystal Chemistry of Ordered Rocksalt-Type SrCaNF

Journal of Chemical Crystallography - A new Group 2 bimetallic nitride fluoride phase of approximate composition SrCaNF has been prepared and characterized via high resolution single crystal X-ray...