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1.
Atmospheric lead and cadmium deposition in bulk precipitation and throughfall was investigated at four forests in the Kanto
district, Japan, to assess the impact of human activities on the environmental health of forests. Annual lead and cadmium
depositions in bulk precipitation ranged from 8.9 to 25.7 g ha−1 year−1 and from 0.77 to 1.30 g ha−1 year−1, respectively. Lead and cadmium deposition increased in the summer at every forest due to large amounts of rainfall. At one
of the forests, the depositions were also high in the winter due to heavy snowfall. These depositions were similar to recent
depositions observed at other rural and urban sites in Japan and several forests in Europe and North America after 1990. These
results indicate that although anthropogenic lead and cadmium are deposited at these rates over wide areas, depositions are
still higher than in remote areas. 相似文献
2.
Yi Min Wei Bunichiro Tomita Yasushi Hiramatsu Atsushi Miyatake Tsuyoshi Fujii Tomoyuki Fujii Shuichiro Yoshinaga 《Journal of Wood Science》2003,49(4):317-326
Poor compatibility was found between exploded wood fiber strand (WFS) and cement due to the excessive presence of water-soluble degraded polysaccharides in extractives of exploded WFS obtained from weathered wood waste treated by the water-vapor explosion process (WVEP). This study presents some comparative results from a continuing investigation on the compressive strengths of exploded WFS–cement mixtures. Based on results previously obtained with the hydration test, the relation between hydration behavior and compressive strength of the mixture was explored. In addition, the effect of the curing age on compressive strength development of the mixture with selected additive chemicals was examined. The results supported the results of early studies with hydration tests indicating that adding MgCl2 to the mixtures of exploded WFS mixed with quick-curing cement or ordinary Portland cement and a composite of MgCl2 + CaO added to the mixture of exploded WFS and furnace-slag cement effectively improved the hydration behaviors; it greatly enhanced the compressive strengths of mixtures as well. Compressive strengths were strongly correlated to maximum hydration temperatures (Tmax) of wood–cement mixtures influenced by the cement type, wood wastes (treated or not with WVEP), additive chemicals, and their content levels. The results also indicated that adding selected chemicals had no significant effect on compressive strength among the mixtures of exploded WFS mixed, respectively, with three types of cement at a curing age of 180 days. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to identify the hydration products and to probe the element distribution of the mixture in the wood–cement interface zone from a fractured surface.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002 相似文献
3.
Nitrogen-fixing activity in decomposing litter of three tree species at a watershed in eastern Japan
Takashi Yamanaka Keizo Hirai Shuhei Aizawa Shuichiro Yoshinaga Masamichi Takahashi 《Journal of Forest Research》2011,16(1):1-7
Nitrogen fixation during litter decomposition was studied for 34 months using litterbags containing newly fallen litter of
coniferous species Cryptomeria japonica and Pinus densiflora and that of deciduous species Quercus serrata. Litterbags were set in contact with the forest floor in a deciduous broad-leaved forest near the top of a slope and in a
C. japonica stand at the middle of the slope at a watershed in eastern Japan. Nitrogen-fixing activity, estimated by acetylene reduction
after 16 and 19 months of incubation, was 62.65–3.86 nmoles C2H4 h−1 g−1 DW in Cryptomeria litter, but only 1.07–0.09 in Pinus and 0.72–0.04 in Quercus. The rate of N increase in decomposing litter was highest in Cryptomeria. Fungal biomass in decomposing litter, estimated by ergosterol content, increased during the initial 16 months of incubation
in Cryptomeria and Quercus, and during the initial 19 months of incubation in Pinus. The litter decomposition rate was highest in Cryptomeria among the three species, due to increased N content and fungal biomass in Cryptomeria litter. Thus, N increase in decomposing Cryptomeria litter affects the subsequent N dynamics and decomposition pattern. 相似文献
4.
5.
Kodama R Okazaki T Sato T Iwashige S Tanigawa Y Fujishima J Moriyama A Yamashita N Sasaki Y Yoshikawa T Kamimura Y Maeda H 《Journal of toxicologic pathology》2012,25(1):55-61
We investigated chronological changes in immunohistochemical phenotyping in the thymus and spleen in Crl:CD rats up to the age of about one year. In the thymus, T cells increased markedly from 3 to 4 weeks of age. Proliferating cells also increased markedly at these points. B cells tended towards an increase with age. In the spleen, white pulp increased until 9 weeks of age and remained fairly stable thereafter. In the periarteriolar lymphoid sheath and marginal zone, T cells gradually increased until 9 weeks of age and became almost flat thereafter. In the lymph follicle, T cells increased with age. B cells tended towards an increase with age in all areas of the spleen. It was concluded that development of the thymus was most marked from 3 to 4 weeks of age and that both the thymus and spleen had matured by 9 weeks of age. 相似文献
6.
Water management methods regulate water temperature in paddy fields, which affects rice growth and the environment. To understand the effect of irrigation conditions on water temperature in a paddy field, water temperature distribution under 42 different irrigation models including the use of ICT water management, which enables remote and automatic irrigation, was simulated using a physical model of heat balance. The following results were obtained: (1) Irrigation water temperature had a more significant effect on paddy water temperature close to the inlet. As the distance from the inlet increased, the water temperature converged to an equilibrium, which was determined by meteorological conditions and changes in water depth. (2) Increasing the irrigation rate with higher irrigation water amount increased the extent and magnitude of the effects of the irrigation water temperature. (3) When total irrigation water amount was the same, increasing the irrigation rate decreased the time-averaged temperature gradient effect over time across the paddy field. (4) Irrigation during the lowest and highest paddy water temperatures effectively decreased and increased the equilibrium water temperature, respectively. The results indicate that irrigation management can be used to alter and control water temperature in paddy fields, and showed the potential of ICT water management in enhancing the effect of water management in paddy fields. Our results demonstrated that a numerical simulation using a physical model for water temperature distribution is useful for revealing effective water management techniques under various irrigation methods and meteorological conditions.
相似文献7.
Kodama R Yang X Araki T Sato M Iwashige S Tanigawa Y Uchimura M Ishimaru K Sasaki Y Kamimura Y Maeda H 《Journal of toxicologic pathology》2010,23(1):53-58
In a seven-year-old male cynomolgus monkey, erythema of the upper eyelid and forehead and corneal opacity, edema and conical protrusion in the eye were observed. At necropsy, ophthalmological and serological examinations revealed binocular corneal opacity and conical protrusion and a high IgE level, respectively. Thinning of the epithelium and stroma of the cornea were noted histopathologically. At the center of the corneal epithelium, the number of epithelial cells was reduced, their cytoplasm was poorer and the basal cells were flatter than at the periphery. Bowman's membrane was folded with partial loss or breakage. Collagen fibers were compacted or disarranged, and the keratocytes were increased in the stroma, with focal pyknosis or loss of the endothelium and folding of Descemet's membrane. Electron microscopical examination revealed atrophy of the corneal epithelial basal cells. This is the first report of a case of keratoconus in a cynomolgus monkey. 相似文献
8.
Tsuyoshi Yamada Shuichiro Yoshinaga Kazuhito Morisada Keizo Hirai 《Water, air, and soil pollution》2001,130(1-4):1115-1120
To assess the influence of acidic deposition on the forest ecosystem, it is necessary to evaluate the gross amount of acidic deposition. In this paper, we discuss the variation of sulfate (SO4 2?) and nitrate (NO3 ?) loads as well as related concentration from 1991 to 1999 in the Hinoki (Chamaecyparis obtusa) plantation in Kochi, southwest Japan. The annual precipitation varied significantly from 1,700 to 3,900 mm during the study period. The annual sulfate concentration of rainfall was about 15 µmol L?1, including about 80% non sea salt sulfate, while the annual nitrate concentration of rainfall was increased. The sulfate and nitrate concentrations of the through fall and the nitrate concentration of the stem flow were equal to or slightly higher than those of rainfall. However, the sulfate concentration of the stem flow was higher than that of rainfall, 21 to 55 µmol L?1. The sulfate and nitrate loads of rainfall were measured to be 27 to 46 and 14 to 43 mmol m?2 y?1, respectively. The sulfate and nitrate loads of the through fall were the same or slightly higher than those of rainfall. In contrast, the sulfate and nitrate loads of the stem flow were less than those of rainfall. Combined sulfate loads of the through fall and the stem flow reached about 1.5 times that of the sulfate load of rainfall. 相似文献
9.
Sasaki Y Kodama R Iwashige S Fujishima J Yoshikawa T Kamimura Y Maeda H 《Journal of toxicologic pathology》2011,24(1):69-73
Severe bilateral cataract was found in a 7 year-old naïve female cynomolgus monkey
(Macaca fascicularis) 3 months before necropsy. During macroscopic
examination, severe opacity and thinning of the lens were observed in both eyes.
Histopathology revealed that the lens nuclei and majority of cortex lens fibers had
disappeared and become excavated, while the lens fibers in the subcapsular area were
swollen and distorted. Other observations included atrophy and vacuolation in the lens
epithelial cells and proliferation of spindle cells and collagen fiber beneath the
anterior capsule of the right eye. Immunohistochemical staining of these spindle cells
revealed the presence of vimentin, cytokeratin and α-smooth muscle actin (α-SMA), which
were considered to be derived from lens epithelial cells. This is a rare case of
spontaneous, bilateral, hypermature cataract in a cynomolgus monkey. 相似文献
10.
Tomoaki Morishita Shuhei Aizawa Shuichiro Yoshinaga Shinji Kaneko 《Journal of Forest Research》2011,16(5):386-393
Temperate forest soils are one source of nitrous oxide (N2O), which is an important greenhouse gas and the most important ozone-depleting substance. To clarify N2O flux mechanisms in relation to soil temperature, moisture, and nitrification activity, we measured N2O fluxes and net nitrification rates over 3 years at the lower (Japanese cedar) and upper (deciduous broad-leaved trees) parts
of a hill slope in a small forest catchment in the northern Kanto region of Japan. The N2O flux was measured by the closed-chamber technique every month, along with soil temperature and water-filled pore space (WFPS).
At the lower slope, the N2O flux increased with increasing soil temperature (r
2 = 0.383, P < 0.01) owing to an increase in the nitrification rate. At the upper slope, no positive linear correlation of N2O flux with soil temperature, WFPS, or nitrification rate was observed. The low N2O flux at the upper slope during summer was caused by the low summertime WFPS there. We attributed the higher mean N2O fluxes observed at the lower slope (median 2.36 μg N m−2 h−1) than at the upper slope (median 1.10 μg N m−2 h−1) to a high soil moisture during summer season in the surface soil of the lower slope. 相似文献