Twisted flavors and tribimaximal neutrino mixing

A new framework for handling flavor symmetry breaking in the neutrino sector is discussed where the source of symmetry breaking is traced to the global property of right-handed neutrinos in extra-dimensional space. Light neutrino phenomenology has rich and robust predictions such as the tribimaximal form of generation mixing, controlled mass spectrum, and no need of flavor mixing couplings in the theory.     

Surface carboxylation of porous regenerated cellulose beads by 4-acetamide-TEMPO/NaClO/NaClO2 system

A commercial regenerated bead cellulose was suspended in water at pH 4.8, and oxidized with NaClO₂ used as a primary oxidant and catalytic amounts of NaClO and 4-acetamide-2,2,6,6-tetramethylpiperidinyl-1-oxyl radical. Carboxylate groups were formed up to 1.87 mmol/g in the beads by the oxidation of C6 primary hydroxyls to carboxylates without significant weight losses or morphological changes. The spherical shapes, highly porous surface structures consisting of nano-sized fibrils, and the cellulose II crystal structure of the original beads were mostly maintained by the oxidation, indicating that the carboxylate groups formed are predominantly present on the fibril surfaces. Cation-exchange behavior of the TEMPO-oxidized cellulose beads was compared with carboxymethylated cellulose beads, showing that the former was characteristic and superior to the latter in terms of adsorption of metal ions and cationic polymers. Especially, the TEMPO-oxidized cellulose beads had high adsorption behavior of lead ion and high-molecular-weight cationic polymers.     

Bacterial memetic algorithm for offline path planning of mobile robots

The goal of the path planning problem is to determine an optimal collision-free path between a start and a target point for a mobile robot in an environment surrounded by obstacles. This problem belongs to the group of combinatorial optimization problems which are approached by modern optimization techniques such as evolutionary algorithms. In this paper the bacterial memetic algorithm is proposed for path planning of a mobile robot. The objective is to minimize the path length and the number of turns without colliding with an obstacle. The representation used in the paper fits well to the algorithm. Memetic algorithms combine evolutionary algorithms with local search heuristics in order to speed up the evolutionary process. The bacterial memetic algorithm applies the bacterial operators instead of the genetic algorithm??s crossover and mutation operator. One advantage of these operators is that they easily can handle individuals with different length. The method is able to generate a collision-free path for the robot even in complicated search spaces. The proposed algorithm is tested in real environment.     

Ab initio GB study of chemical intermediates in solution; Ethylenesulfonium ion in hydrolysis of 2-chloroethyl methyl sulfide

Ab initio MO theory including solvent effects has been applied to the structure and reactivity of methyl ethylenesulfonium ion, 1 , in aqueous solution as a model of the three-membered cyclic sulfonium intermediate expected in the toxic action of sulfur mustard. The 6-31 + G* geometry optimization of the cyclic sulfonium ion 1 suggested that the ring size of 1 is expanded slightly by solvation. The contour lines map of the interaction energy between 1 and Cl⁻ has a very shallow and wide well at 5–6 Å distance from 1 . This is the solvent-separated ion pair, and the contact ion pair was not found between 1 and Cl⁻. The calculated energy diagrams for the S_N2-type reactions of 1 with Cl⁻, H₂O, and OH⁻ that give ring-opened compounds indicated the following: (1) The energy of the 1 + Cl⁻ system is similar to that of chloroethyl methyl sulfide (CEMS, 2 ), and the interconversion between 1 + Cl⁻ and 2 occurs easily in aqueous solution. The 3-21 + G(*) and 6-31 + G* activation energies for the 2 → 1 + Cl⁻ reaction, 20–22 kcal/mol, agree well with the experimental enthalpy of activation for the hydrolysis of 2 . (2) The reaction of 1 with OH⁻ gives a very stable hydroxyl compound, 4 , and no transition state was found. (3) The reaction of 1 with H₂O gives an unstable addition product that is expected to be converted to 4 with the assistance of another H₂O molecule. This mechanism is consistent with that proposed by Bartlett and Swain in their pioneering work on the hydrolysis of sulfur mustard. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:503–510, 1998