Stochastic Estimation of Nuclear Level Density in the Nuclear Shell Model: An Application to Parity-Dependent Level Density in 58^{58}Ni

We introduce a novel method to obtain level densities in large-scale shell-model calculations. Our method is a stochastic estimation of eigenvalue count based on a shifted Krylov-subspace method, which enables us to obtain level densities of huge Hamiltonian matrices. This framework leads to a successful description of both low-lying spectroscopy and the experimentally observed equilibration of $J^\pi=2^+$ and $2^-$ states in $^{58}$Ni in a unified manner.Comment: 13 pages, 4 figure

HAND PROPULSION TECHNIQUE OF SKILLED SPRINT SWIMMERS

This study investigated the technique of skilled sprint front-crawl swimmers in terms of the exertion of hand propulsive forces quantified by the dynamic pressure approach. Four skilled sprint front-crawl swimmers, who can swim a 100 m in less than 49 seconds, swam at a 25 m swimming pool where a motion capture system for above and under water was set up. Pressure sensors were attached on the hand to estimate hydrodynamic forces acting on the hand. The mean propulsions in the downsweep, insweep, and upsweep were 26 ± 4 N, 57 ± 12 N, and 46 ± 9 N, respectively. The four swimmers used propulsive lift of 36 ± 6 N in the downsweep, propulsive drag of 40 ± 7 N in the insweep, and propulsive drag and lift of 25 ± 9 N and 21 ± 10 N in the upsweep while swimming at their race pace

Superlattice formation lifting degeneracy protected by non-symmorphic symmetry through a metal-insulator transition in RuAs

The single crystal of RuAs obtained by Bi-flux method shows obvious successive metal-insulator transitions at T_MI1~255 K and T_MI2~195$ K. The X-ray diffraction measurement reveals a formation of superlattice of 3x3x3 of the original unit cell below T_MI2, accompanied by a change of the crystal system from the orthorhombic structure to the monoclinic one. Simple dimerization of the Ru ions is nor seen in the ground state. The multiple As sites observed in nuclear quadrupole resonance (NQR) spectrum also demonstrate the formation of the superlattice in the ground state, which is clarified to be nonmagnetic. The divergence in 1/T_1 at T_MI1 shows that a symmetry lowering by the metal-insulator transition is accompanied by strong critical fluctuations of some degrees of freedom. Using the structural parameters in the insulating state, the first principle calculation reproduces successfully the reasonable size of nuclear quadrupole frequencies for the multiple As sites, ensuring the high validity of the structural parameters. The calculation also gives a remarkable suppression in the density of states (DOS) near the Fermi level, although the gap opening is insufficient. A coupled modulation of the calculated Ru d electron numbers and the crystal structure proposes a formation of charge density wave (CDW) in RuAs. Some lacking factors remain, but it shows that a lifting of degeneracy protected by the non-symmorphic symmetry through the superlattice formation is a key ingredient for the metal-insulator transition in RuAs.Comment: 10 pages, 10 figure

Explicitly Multi-Modal Benchmarks for Multi-Objective Optimization

In multi-objective optimization, designing good benchmark problems is an important issue for improving solvers. Although many benchmark problems have been proposed and some of them became de facto standards, designing multimodal problems that have a controllable landscape is still an open problem especially for high-dimensional cases. We thus propose the Benchmark with Explicit Multimodality (BEM), which lets the benchmark designer specify the basins of attraction using a graph structure known as the reachability graph. In this article, we focus on the mathematical formulation of the BEM. We will see that the BEM has preferable characteristics such as (i) realizing user-specified local Pareto set, (ii) allowing high-dimensional design spaces and (iii) possessing nonseparability

Pre-steady-state kinetic studies of redox reactions catalysed by Bacillus subtilis ferredoxin-NADP+ oxidoreductase with NADP+/NADPH and ferredoxin

Ferredoxin-NADP+ oxidoreductase ([EC1.18.1.2], FNR) from Bacillus subtilis (BsFNR) is a homodimeric flavoprotein sharing structural homology with bacterial NADPH-thioredoxin reductase. Pre-steady-state kinetics of the reactions of BsFNR with NADP+, NADPH, NADPD (deuterated form) and B. subtilis ferredoxin (BsFd) using stopped-flow spectrophotometry were studied. Mixing BsFNR with NADP+ and NADPH yielded two types of charge-transfer (CT) complexes, oxidized FNR (FNRox)-NADPH and reduced FNR (FNRred)-NADP+, both having CT absorption bands centered at approximately 600 nm. After mixing BsFNRox with about a 10-fold molar excess of NADPH (forward reaction), BsFNR was almost completely reduced at equilibrium. When BsFNRred was mixed with NADP+, the amount of BsFNRox increased with increasing NADP+ concentration, but BsFNRred remained as the major species at equilibrium even with about 50-fold molar excess NADP+. In both directions, the hydride-transfer was the rate-determining step, where the forward direction rate constant (~ 500 s- 1) was much higher than the reverse one (< 10 s- 1). Mixing BsFdred with BsFNRox induced rapid formation of a neutral semiquinone form. This process was almost completed within 1 ms. Subsequently the neutral semiquinone form was reduced to the hydroquinone form with an apparent rate constant of 50 to 70 s- 1 at 10 °C, which increased as BsFdred increased from 40 to 120 μM. The reduction rate of BsFNRox by BsFdred was markedly decreased by premixing BsFNRox with BsFdox, indicating that the dissociation of BsFdox from BsFNRsq is rate-limiting in the reaction. The characteristics of the BsFNR reactions with NADP+/NADPH were compared with those of other types of FNRs. © 2016 Elsevier B.V. All rights reserved.Embargo Period 12 month