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We study the assisted adiabatic passage, and equivalently the transitionless quantum driving, as a quantum brachistochrone trajectory. The optimal Hamiltonian for given constraints is constructed from the quantum brachistochrone equation. We discuss how the adiabatic passage is realized as the solution of the equation. The formulation of the quantum brachistochrone is based on the principle of least action. We utilize it to discuss the stability of the adiabatic passage., Comment: 16 pages, 4 figures; minor changes for v2

We present a prototype of behavior of glassy systems driven by quantum dynamics in a quenching protocol by analyzing the random energy model in a transverse field. We calculate several types of dynamical quantum amplitude and find a freezing transition at some critical time. The behavior is understood by the partition-function zeros in the complex temperature plane. We discuss the properties of the freezing phase as a dynamical chaotic phase, which are contrasted to those of the spin-glass phase in the static system., 6 pages, 5 figures

We investigate partition-function zeros of the many-body interacting spherical spin glass, the so-called $p$-spin spherical model, with respect to the complex temperature in the thermodynamic limit. We use the replica method and extend the procedure of the replica symmetry breaking ansatz to be applicable in the complex-parameter case. We derive the phase diagrams in the complex-temperature plane and calculate the density of zeros in each phase. Near the imaginary axis away from the origin, there is a replica symmetric phase having a large density. On the other hand, we observe no density in the spin-glass phases, irrespective of the replica symmetry breaking. We speculate that this suggests the absence of the temperature chaos. To confirm this, we investigate the multiple many-body interacting case which is known to exhibit the chaos effect. The result shows that the density of zeros actually takes finite values in the spin-glass phase, even on the real axis. These observations indicate that the density of zeros is more closely connected to the chaos effect than the replica symmetry breaking., 22 pages, 8 figures

We study effects of random fluctuations in quantum spin-glass systems. We show that the expression of the magnetic susceptibility is divided into the classical and quantum parts. The former can be analyzed by the standard replica method with the static approximation. The latter incorporates dynamical correlations and is determined by the energy gap distribution. By using the many-body interacting Ising spin-glass model with transverse field, we discuss possible mechanisms of the quantum phase transitions.

We study the effects of random fluctuations on quantum phase transitions by the energy gap analysis. For the infinite-ranged spin-glass models with a transverse field, we find that a strong sample-to-sample fluctuation effect leads to broad distributions of the energy gap. As a result, the linear, spin-glass, and nonlinear susceptibilities behave differently from each other. The power-law tail of the distribution implies a quantum Griffiths-like effect that could be observed in various random quantum systems. We also discuss the mechanisms of the phase transition in terms of the energy gap by comparing the Sherrington-Kirkpatrick model and random energy model, which demonstrate the difference between the continuous and discontinuous phase transitions., Comment: 4 pages, 5 figures; fig.3 replaced, minor changes

We investigate electron transport through quantum dots embedded in an Aharonov–Bohm ring. One or both of the dots are chaotic and are treated by random matrix theory. The conductance and conductance fluctuations are calculated as a function of the ratio of the level broadening to the average level spacing in the random dots using random scattering matrix theory with a Poisson kernel. Several interference mechanisms in the ring are examined. When one random dot and a single resonance level coexist and the multiple reflection between them is taken into account, the conductance is suppressed as the Fermi level of the leads approaches resonance in the large level broadening regime. For coupled random dot systems, characterized by two different ratios, the conductance is sensitive to the difference between the ratios when the multiple scattering inside the ring is disregarded, while it does not depend on the difference when the scattering is effective.

The effects of seasonal changes and sexual maturation on the serum bactericidal activity in rainbow trout Salmo gairdneri were investigated.Two fish populations separated in spawning season were studied. One population reared under natural environmental conditions had spawning period between September and November, while the other reared under controlled day length had spawning period between April and June.The sera collected from trout were pooled together and mixed with an Escherichia coli suspension. This mixture was incubated at 25°C for 6h. After incubation the number of viable bacteria were counted by the plate counting method and the survival rate was calculated.Among the heated (45°C for 30 min) sera, the bacteria multiplied about 10 times during the 6h incubation. In contrast, the bacterial count in the normal sera decreased in number to about one tenth of the initial count after 6h. However, the normal sera sampled during spawning period showed an increase of bacteria. This change of the serum bactericidal activity level was observed in both fish populations. In addition, the bactericidal activity level of the sera from fish before being stripped was lower than that from fish after being stripped. From these results, it is probable that the decrease of the serum bactericidal activity during the spawning period increase the susceptibility to disease in fish.

Seasonal reproductive biology was investigated in 2 species of Archaeomysis, each of which occurs in distinctive habitats, intertidal and infralittoral areas of a sandy beach of NE Japan. The seasonal reproductive patterns of the 2 species are similar, with 3 breeding peaks from spring to autumn. The populations are initially dominated by larger sized overwintering and then smaller sized spring/summer generations. However, intertidal A. kokuboi exhibits a more extended breeding period than infralittoral A. japonica. The brood size (number of Stage I larvae female -1 ) increased with increasing size of females and averaged 12 to 72 for A. kokuboi and 10 to 55 for A. japonica, showing a higher brood size in the overwintering individuals of A. kokuboi. The larval size and development time and the interval between broods decreased with increasing temperature; and development took much longer in A. japonica at the lower temperature range. In overwintering gen- erations, the larval (Stage I) production rate of A. kokuboi (0.9 to 3.4 larvae female -1 d -1 ) was higher than in A. japonica (0.6 to 2.1), while after July the rate of both species fluctuated in almost the same range (0.4 to 1.9). The specific larval production rate of both species was significantly related to water temperature and was 17 to 38% higher in A. kokuboi than in A. japonica throughout the year. This study found that A. kokuboi retains a higher reproductive effort to settle into the intertidal zone of sandy beaches, but does not show any specialization to the basic reproductive features, such as an altered generation pattern or a change in larval size. The retention of a high reproductive potential in A. kokuboi is an adaptation to the intertidal zone of sandy beaches which is characterized by a high mortality rate due to unpredictable events such as storms, while efficient reproduction during the high water temperature season in A. japonica is an adaptation to the infralittoral habitat where more predictable events, such as seasonal variation of temperature, prevail as environmental variables.

We measured field abundances, feeding rates, swimming behavior, and particle colonization of two harpacticoids, the pelagic Microsetella norvegica and the semibenthic Amonardia normanni,to examine (1) if aggregates have a significant role in harpacticoid nutrition and (2) if harpacticoids contribute significantly to aggregate degradation. Neither of the harpacticoids was able to feed efficiently on suspended food, while both grazed well on attached food, indicating that pelagic harpacticoids depend on food attached to surfaces, such as those offered by marine aggregates. We estimated that the two harpacticoids are able to search substantial volumes of water for aggregates (up to 1.2 L d 21 ), and that during bloom conditions in the North Sea, reported aggregate concentrations allow M. norvegica to daily encounter about three aggregates. High short-term hunger-induced feeding rates observed in A. normanni indicate that at least some harpacticoid species can fill their gut during few short visits to aggregates. Harpacticoids may cause substantial degradation of aggregates of ,1 cm (5‐100%) when their abundance exceeds 10 5 m 22 , which is not atypical during summer in temperate waters.

1986年2月, 山梨県魚苗センター忍野幼魚場において飼育中のイワナふ化仔魚に大量斃死が発生した。斃死魚から分離された細菌は, グラム陰性, 偏性好気性で運動性を有し, チトクロームオキシダーゼ, カタラーゼ陽性, グルコースを酸化的に分解し, King B 培地においてフルオレシンを産生した。これらの性状から, 分離菌は, Pseudomonas fluorescens に同定された。また, 攻撃試験の結果, 本菌はイワナ以外に, ニジマス, ヤマメ, アユに対しても病原性を有することが確認され, 今回の斃死の原因菌と判断された。