Takahito Yoshioka

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Quantitative and qualitative characterizations of dissolved organic matter (DOM) were carried out at the watershed level in central Japan by measuring dissolved organic carbon (DOC) concentration and the three-dimensional excitation–emission matrix (3-D EEM). DOC concentration was low (mean 37 ± 19 µM C) in the upstream waters, whereas, in general, it(More)
Dissolved organic carbon (DOC) and NO 3 − are important forms of C and N in stream water. Hypotheses concerning relationships between DOC and NO 3 − concentrations have been proposed, but there are no reports demonstrating a relationship between them in stream water. We observed 35 natural streams in the Lake Biwa watershed, central Japan, and found an(More)
Color and orientation processing in the macaque monkey first segregates into cytochrome oxidase (CO)-rich blobs and -poor interblobs of area V1, from where the two streams flow through areas V2 and V4. This parallel representation is believed to enhance processing speed by compartmentalizing tasks of similar kinds, though our knowledge of the mechanisms is(More)
A landmark study conducted by Berlin and Kay (Basic Color Terms, University of California Press, Berkeley, 1969, pp. 1-12) demonstrates that well-developed languages contain exactly 11 basic color terms. The basic colors (8 chromatic and 3 achromatic) are situated in specific locations of color space, suggesting a fixed relationship between specific hue and(More)
*Corresponding author (e-mail: yoshioka@kais.kyoto-u.ac.jp) *Present address: Field Science Education and Research Center, Kyoto University, Kitashirakawa, Oiwake, Kyoto 606-8502, Japan. **Present address: Institute of Geochemistry, The Chinese Academy of Sciences, 46 Guanshui Road, Guiyang/Guizhou 550002, China. †Present address: NPO Mori-no-za, Ina(More)
Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO − 3 , and CO 2− 3 ) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The(More)
Fungal infection of the filamentous cyanobacterium Anabaena smithii was observed in Lake Shumarinai in 2004–2006. Two fungal species were found to parasitize the specialized cells of A. smithii. These fungi might not correspond to the chytrid species that the previous studies reported as the parasites for Anabaena species. One fungus showed selective(More)
Distributions of molecular size and fluorescence properties of dissolved organic matter (DOM) in the Lake Biwa and Lake Baikal watersheds were investigated using the cross-flow ultrafiltration technique and three-dimensional fluorescence measurements. From the fluorescence properties, protein-like substances were usually found in the 0.1 μm-GF/F fraction(More)
We investigated soil net nitrogen mineralization rate, above- and belowground biomass allocation, and nitrogen use in a Cryptomeria japonica plantation chronosequence. Total biomass accumulation showed an asymptotic accretion pattern, and the peak total biomass accumulation rate occurred approximately 30 years after afforestation. Soil net nitrogen(More)
This study investigated the sources of organic matter and sediment depositional environment within fluviatile sediments of the Ganges–Meghna (GM) delta plains. The very low contents of trace metals e.g., chromium (Cr), cobalt (Co), scandium (Sc), and vanadium (V), organic carbon content, and cerium (Ce)-anomaly data of sediments indicate the redox(More)