Determination of Boundary Scattering, Intermagnon Scattering, and the Haldane Gap in Heisenberg Chains

Low-lying magnon dispersion in a S=1 Heisenberg antiferromagnetic (AF) chain is analyzed using the non-Abelian DMRG method. The scattering length $a_{\rm b}$ of the boundary coupling and the inter-magnon scattering length $a$ are determined. The scattering length $a_{\rm b}$ is found to exhibit a characteristic diverging behavior at the crossover point. In contrast, the Haldane gap $\Delta$, the magnon velocity $v$, and $a$ remain constant at the crossover. Our method allowed estimation of the gap of the S=2 AF chain to be $\Delta = 0.0891623(9)$ using a chain length longer than the correlation length $\xi$.Comment: 6 pages, 3 figures, 1 table, accepted in Phys. Rev.

Shoot growth chronology of alpine dwarf pine (Pinus pumila) in relation to shoot size and climatic conditions: a reassessment

Shoot growth chronology of alpine dwarf pine (Pinus pumila) was examined near the summit of Mount Norikura in central Japan, in relation to shoot size and climatic conditions. Shoot growth was investigated in 70 shoots with various shoot lengths between 18 and 273cm, and the examined 70 shoots were divided into three size classes (shoot length 140cm). A shoot growth chronology was developed for each of the three size classes, but was not statistically different among them. It is suggested that the size dependency of shoot growth chronology was rather weak or negligible. Thus, a single shoot growth chronology was developed again, irrespective of shoot size. Climatic factors affecting the shoot growth were analyzed by using monthly climatic data (mean temperature, insolation duration and sum of precipitation). The shoot growth chronology was positively correlated with the June temperature of the current year, suggesting that the high temperature of this month increases the shoot growth by prolonging the growing season. The shoot growth chronology was also positively correlated with the temperatures from July to October of the previous year, suggesting that the growth of P. pumila largely depends on the photosynthetic production of the previous year. The mean temperature during July to October of the previous year explained 30% of the variation of the shoot growth chronology. These results showed that the shoot growth of P. pumila is largely regulated by temperature during the growing season, irrespective of shoot size

Seasonal changes in soil temperature on an upper windy ridge and lower leeward slope in Pinus pumila scrub on Mt. Shogigashira, central Japan

The seasonal changes in soil temperature at 5 cm below the surface were monitored on an upper windy ridge (2675 m a.s.l.) and lower leeward slope (2640 m a.s.l.) in Pinus pumila scrub on Mt. Shogigashira in central Japan, from October 2001 to September 2002. The scrub heights were ca. 20 cm and 100 cm on the upper windy ridge and lower leeward slope, respectively. The soil temperature on the upper windy ridge decreased from the autumn to mid-February and increased thenceforth. The soil temperature was sometimes lower than -10°C in winter. In contrast, the soil temperature on the lower leeward slope was relatively stable at about -1°C during the winter. It appears that accumulation of snow prevented cooling of the soil surface. In the snow-free period, the daily maximum soil-temperature was higher on the upper windy ridge than on the lower leeward slope. This difference was evident in May after the snowmelt, and decreased gradually toward the autumn. The solar radiation was highest at around the summer solstice. Much solar radiation penetrated to the soil surface on the upper windy ridge because of its poorly developed canopy, which increased the soil temperature. Thus, this study shows that seasonal changes in soil temperature are different between the upper windy ridge and lower leeward slope due to snow accumulation, canopy development and seasonal changes in solar radiation

Information theoretic interpretation of frequency domain connectivity measures

To provide adequate multivariate measures of information flow between neural structures, modified expressions of Partial Directed Coherence (PDC) and Directed Transfer Function (DTF), two popular multivariate connectivity measures employed in neuroscience, are introduced and their formal relationship to mutual information rates are proved.Comment: 17 pages, 1 figur

木材の腐朽機構に関する研究(第2報) : 腐朽にともなうブナおよびスギ材の赤外スペクトルの変化

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました

Action of Soft Rot- and White Rot Fungi on Partially Delignified Softwoods

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Fourty-four species of softwoods were partially delignified with acidified sodium chlorite for 6 hours at 40℃ and exposed to a soft rot fungus, Chaetomium globosum KUNZE, for 8 weeks at 28℃. The weight losses after the chlorite treatment considerably varied with species. The lowest weight loss was 1.6 % for Chamaecyparis obtusa and the highest was 21.9 % for Larix gmelini. The weight losses after the exposure to Ch. globosum noticeably increased in proportion to the degree of delignification. The highest weight loss was 58.2 % for Picea glehnii and the lowest was 6.2 % for Chamaecyparis obtusa. Furthermore, the pattern of acceleration of wood decay by the chlorite treatment has been studied for two softwoods and one hardwood, with reference to the decrease of total lignin content, using Ch. globosum and a white rot fungus, Coriolus versicolor QUEL. The results showed that the effect of delignification was positively observed in all woods for both fungi but considerably varied with wood and fungal species. In the case of Pinus densiflora, the maximum level of wood decay was reached at about 43 % of delignification for Ch. globosum and at greater stage of delignification for Co. versicolor. In Cryptomeria japonica, the maximum level was at 50 % or more for Ch. globosum and at about 18 % for Co. versicolor. Maximum levels in both woods for Ch. globosum were higher than those for Co. versicolor, in spite of lower attacking capacity of the former on original woods. In Fagus crenata, highly susceptible to both fungi, acceleration was not greater than in the two softwoods