The bacterial flora and biomass in mountain snow from the Tateyama Mountains, Toyama Prefecture, Japan, one of the heaviest snowfall regions in the world, were analyzed by amplified ribosomal DNA restriction analysis followed by 16S rRNA gene sequencing and DNA quantification by real-time PCR. Samples of surface snow collected in various months during the melting season contained a psychrophilic bacterium, Cryobacterium psychrophilum, and two psychrotrophic bacteria, Variovorax paradoxus and Janthinobacterium lividum. Bacterial colonies that developed in an in situ meltwater medium at 4°C were revealed to be V. paradoxus. The biomasses of C. psychrophilum, J. lividum, and V. paradoxus, as estimated by real-time PCR, showed large increases during the melting season from March to October (2.0 ؋ 10 5 -fold, 1.5 ؋ 10 5 -fold, and 1.0 ؋ 10 4 -fold increases, respectively), suggesting their rapid growth in the surface snow. The biomasses of C. psychrophilum and J. lividum increased significantly from March to April, reached a maximum in August, and dropped at the end of the melting season. In contrast, the biomass of V. paradoxus did not increase as rapidly during the early melting season but continued to increase from June until October. The differences in development observed among these bacterial species suggest that their growth was promoted by different nutrients and/or environmental conditions in the snow. Since these three types of bacteria have also been reported to be present in a glacier in Antarctica and a Greenland ice core, they seem to be specialized members of the snow biota that are distributed in snow and ice environments in various parts of the world.
We investigated electron transport kinetics in terms of electron diffusion coefficient (D) and electron lifetime (tau) in coumarin-dye-sensitized nanocrystalline TiO2 electrodes by intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS). We found that the values of tau for coumarin-dye-sensitized TiO2 electrodes were much shorter than that for an electrode coated with a Ru complex (N719 dye), suggesting that the back-electron-transfer process corresponding to recombination between conduction-band electrons in the TiO2 and I3- ions in the electrolyte occurs more easily in coumarin-dye-sensitized solar cells. In addition, the values of tau depended on the kind of coumarin dye, each of which has a different number of thiophene moieties, suggesting that the molecular structure of the adsorbed dyes also affects the kinetics of electron transport in the TiO2 electrodes.
A large number of studies have used firm-level data to examine whether foreign direct investment (FDI) generates knowledge spillovers to domestically owned firms in less developed countries. However, the results are mixed. In this study, Indonesian plant-level panel data are used to test whether the often-ignored local R&D activities of foreign-owned firms in the host country enhance knowledge spillovers from FDI. The analysis found positive spillovers from R&D-performing foreign-owned firms, while spillovers from non-R&D-performing foreign-owned firms were absent.
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