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Abstract The abundance and species composition of Parmales (Bolidophyceae), a siliceous marine phytoplankton, were investigated in the waters surrounding Hokkaido, North Japan. In the Pacific Ocean, high Parmales abundances were observed in the Oyashio region (84.9–95.2 cells mL−1), in the surrounding area of the cold Oyashio Current, and in the Coastal Oyashio Water (35.1–41.4 cells mL−1) being low temperature and salinity in spring. In the Okhotsk Sea, Parmales abundance was moderate (>5 cells mL−1) in the Intermediate Cold Water, which is formed by convective mixing under the pack ice. On the other hand, their abundance was quite low in warm water masses, such as the Tsushima Warm Current in the Sea of Japan and the Soya Warm Current in the Okhotsk Sea. Parmales cells were also found in the sea ice in the Notoro-ko Lagoon connected to the Okhotsk Sea, suggesting that they have an ice algal life cycle. Triparma spp. were almost dominant in the study areas with the occasional contribution of Tetraparma spp. in the Okhotsk Sea. These results indicate that Parmales abundance and species composition are significantly influenced by water currents. [ABSTRACT FROM AUTHOR]

In order to investigate the crossover from the homogeneous behavior to percolative one for two-dimensional system, the temperature T and magnetic field H dependence of the sheet resistance Rsq have been measured for thin granular aluminum films. In a magnetic field of 5 T, the conductance σ decreases with decreasing T as σ=αTe2/(2π2ℎ) ln T+σ0 due to weak localization effect. The value of αT decreases when Rsq increases beyond 6∼8 kΩ. In the network which does not contain loops smaller than the phase relaxation length, weak localization effect is considered to be suppressed. We have obtained the anomalous T-dependent diffusion constant D from the analysis of the magnetoconductance above TC with use of the fitting parameter D(T). These behaviors can be explained qualitatively by a model of scaling law for percolation. [Copyright &y& Elsevier]

Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2 Hz) stimulation for 15 min applied to layer 4 induces T-type Ca 2+ channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice. We found that 2 Hz stimulation induced LTP of extracellular field potentials evoked by stimulation of layer 4 in layer 2/3 in adulthood as during the critical period. LTP in adulthood was blocked by L-type, but not T-type, Ca 2+ channel antagonists, whereas LTP during the critical period was blocked by T-type, but not L-type, Ca 2+ channel antagonists. This developmental change in LTP was prevented by dark rearing. Under pharmacological blockade of GABA A receptors, T-type Ca 2+ channel-dependent LTP occurred, whereas L-type Ca 2+ channel-dependent LTP did not occur. These results suggest that different forms of synaptic plasticity can contribute separately to experience-dependent modification of visual responses during the critical period and in adulthood. [ABSTRACT FROM AUTHOR]

This study investigated the effects of balance exercise combined with whole-body vibration (WBV) on step performance and lower limb muscle activity during simulated forward falls using the tether-release method in older women. Twenty older women were assigned to either a WBV plus balance exercise group (WBV, n = 10) or a balance exercise without vibration group (standard balance exercise group [STE], n = 10). WBV performed weight-bearing exercises on a WBV platform combined with other balance exercises as a home program, whereas STE performed the same exercises without WBV. The exercise volume was equal in both intervention groups (3×/week for 12 weeks × 30 min/session). The EMG and kinematic data of the stepping leg from the balance recovery step were examined before and after the intervention. While both groups extended step length during forward falls after the intervention, only WBV increased step velocity. EMG analysis of the balance recovery step showed that both groups increased peak EMG of knee flexor and extensor muscles after intervention. After intervention, WBV increased peak EMG of the plantar flexors, which are used to exert the push-off forces just before the leg swing. Balance exercise in older women resulted in significant improvements in the balance recovery step after a simulated forward fall. WBV also had the additional benefit of improved step velocity, which was reflected in increased activity of the plantar flexors in the stepping leg. [ABSTRACT FROM AUTHOR]