Polarized electron capture by3He2+ at 20–28 keV

Nuclear polarization was measured by means of beam foil spectroscopy for a³He⁺ ion produced by an electron capture process of a³He²⁺ from a polarized sodium atom in an incident energy range from 20 to 28 keV. Assuming that a polarized electron of a sodium atom is predominantly captured to the 3d orbital of a³He⁺ ion andcascades down to the 1s ground state via the 2p orbital, an alignment factorA ₀ ^col (L=2) for the 3d orbital of a³He⁺ ion was extracted by comparing the observed initial sodium polarization andfinal nuclear polarization. The observedA ₀ ^col (L=2) showed a less pronounced energy dependence andwere qualitatively reproduced by the theoretical calculation.     

Quasi-classical limit of Toda hierarchy andW-infinity symmetries

Previous results on quasi-classical limit of the KP hierarchy and itsW-infinity symmetries are extended to the Toda hierarchy. The Planck constant now emerges as the spacing unit of difference operators in the Lax formalism. Basic notions, such as dressing operators, Baker-Akhiezer functions, and tau function, are redefined.W _{1 +} symmetries of the Toda hierarchy are realized by suitable rescaling of the Date-Jimbo-Kashiara-Miwa vertex operators. These symmetries are contracted tow _{1 +} symmetries of the dispersionless hierarchy through their action on the tau function.     

Nuclear spin dependence of polarization enhancement by multi-tilted foils studied by short-lived beta-emitters8B and12B

In order to study the basic mechanism of polarization enhancement realized by the multitilted foil technique, nuclear polarization of short-lived beta-emitter⁸B(T_1/2=769 ms,I =2⁺) was induced. Utilizing up to ten tilted foils, the polarization enhancement was measured as a function of the foil numbers. The observed enhancement for⁸B was combined with the previous results for¹²B(I =1⁺,T _1/2=20 ms) which has the same atomic configurations but different nuclear spin. Analyzing these results in the framework of the classical vector model, the essential features of the enhancement depending on the nuclear spin was disclosed.     

Traffic dispersion induced by noise in off-lattice model

We study the dispersion of vehicles induced by speed fluctuation on a single-lane highway under open boundary. We extend the cellular automaton model on one-dimensional lattice to the real-variable model on off-lattice (continuous-in space model) in order to take into account the fluctuation of vehicular speed. Vehicles extend over the highway when moving forward. The characteristics of traffic dispersion are derived. It is shown that vehicular traffic exhibits scaling property. When a vehicle accelerates for following the vehicle ahead, vehicles move forming a cluster without dispersion. The relationship between the width of vehicular cluster and acceleration rate is clarified.     

Imprinting modulates processing of visual information in the visual wulst of chicks

Background  

Imprinting behavior is one form of learning and memory in precocial birds. With the aim of elucidating of the neural basis for visual imprinting, we focused on visual information processing.