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31.
Toru Kohama Nobuya Mizoue Satoshi Ito Akio Inoue Kotaro Sakuta Hiroyuki Okada 《Journal of Forest Research》2006,11(4):235-242
We examined the extent to which direct and indirect measures of light and microsite conditions could explain variation in
tree height and diameter at the base of 6-year-old Cryptomeria japonica trees planted in a group selection opening of about 0.32 ha on a steep slope at Shiiba, Miyazaki Prefecture, southern Japan.
We first used the gap light index (GLI) and soil thickness (ST) as directly measured indices. For an indirect measure of light, we used a between-cohort competition index (BCI) estimated from the position and total height of residual trees. For indirect measures of microsite, we examined topographic
indices (slope, plan and profile curvature, average slope gradient, and relative elevation) derived from digital elevation
models (DEMs) with different resolutions ranging from 2 to 10 m. The multiple linear regression using GLI and ST explained about 45% of variation in tree size, while simple regression using only GLI explained about 35%. The contribution of ST was about half of GLI. The multiple regressions using BCI and the topographic indices did not explain any more variation than using BCI alone (R
2 of about 0.26). We conclude that microsite conditions with shallower soil and steeper slope have negative effects on tree
growth in group selection openings, although the relative importance is smaller than light conditions. More comprehensive
studies considering several openings with more heterogeneous topography including different species are needed to generalize
our growth prediction using the indirect measures, which are useful for practical forest management. 相似文献
32.
Rashmi Kumari Hirokazu Ito Masahiro Takatani Miho Uchiyama Tadashi Okamoto 《Journal of Wood Science》2007,53(6):470-480
Although wood/cellulose-plastic composites (WPC) of low wood/cellulose content have been more accepted worldwide and are promoted
as low-maintenance, high-durability building products, composites containing high wood/cellulose content are not yet developed
on an industrial scale. In this study, flow properties, mechanical properties, and water absorption properties of the compounds
of cellulose microfiber/polypropylene (PP) and maleic anhydride-grafted polypropylene (MAPP) were investigated to understand
effects of the high cellulose content and the dimensions of the cellulose microfiber. The molding processes studied included
compression, injection, and extrusion. It was found that fluidity is not only dependent on resin content but also on the dimension
of the filler; fluidity of the compound declined with increased fiber length with the same resin content. Dispersion of the
composite was monitored by charge-coupled device (CCD) microscope. Increasing the plastic content in the cellulose-plastic
formulation improved the strength of mold in addition to the bond development between resin and filler, and the tangle of
fibers. The processing mode affected the physicomechanical properties of the cellulosic plastic. Compression-molded samples
exhibited the lowest modulus of rupture (MOR) and modulus of elasticity (MOE) and the highest water absorption, while samples
that were injection-molded exhibited the highest MOR (70 MPa) and MOE (7 GPa) and low water absorption (2%). 相似文献
33.
Tetsuji Ota Tsuyoshi Kajisa Nobuya Mizoue Shigejiro Yoshida Gen Takao Yasumasa Hirata Naoyuki Furuya Takio Sano Raul Ponce-Hernandez Oumer S. Ahmed Heng Sokh Vuthy Ma Eriko Ito Jumpei Toriyama Yukako Monda Hideki Saito Yoshiyuki Kiyono Sophal Chann Nang Ket 《Journal of Forest Research》2015,20(6):484-492
34.
35.
Tadanori Yamaguchi Shiro Ito Katsuyuki Hamasaki Shuichi Kitada 《Fisheries Science》2006,72(2):233-238
ABSTRACT: To evaluate the stocking effectiveness of the kuruma prawn Penaeus japonicus , a two-stage sampling survey of Gensiki bottom-drift-netters was carried out in Ariake Sound, Saga Prefecture, Japan. A total of 471 000 hatchery-produced juveniles, marked by cutting off the right uropods, was released. Thirty-three fishing days were randomly drawn from four boats, which were selected from the 80 boats operating in the fishery. All prawns caught on the selected days were examined, and the hatchery-produced individuals were identified by their regenerated uropods. A telephone survey of all boats was also conducted, to determine the number of fishing days. A total of 286 marked prawns were caught on the survey days for the Saga area in Ariake Sound, from the last half of July to the first half of September 2002. The recapture rate and standard error were estimated at 0.76 ± 0.52%. Economic efficiency was estimated at 0.28 ± 0.02. Strategies for sampling schemes and stock recovery are also discussed. 相似文献
36.
37.
Tsutomu Hattori Yoji Narimatsu Masaki Ito Yuji Ueda Kunihiro Fujiwara Daiji Kitagawa 《Fisheries Science》2007,73(2):341-347
ABSTRACT: The biomass of bighand thornyhead Sebastolobus macrochir was increased by the high recruitment success of the 1999–2002 year classes off the Pacific coast of northern Honshu, Japan. In this study, the growth of bighand thornyhead was examined over a 9-year period from 1996 to 2004 in this area. The growth of the 1999 year class and the 2000–2002 year classes was reduced at 3 and 2 years old, respectively, while the 1999–2002 year classes were smaller than the 1993–1998 year classes. In 2-, 3- and 4-year-old fish, the relationship between abundance and mean standard length was expressed by negative linear regressions, while fish became smaller when abundance of the year class was larger. Mean bottom temperatures were stable at depths of 350–900 m; variations in water temperature were small in the main distribution area of bighand thornyhead. We discuss the factors affecting the growth of bighand thornyhead via changes in the demersal fish community and feeding habits. 相似文献
38.
Katsuji Uetake Yumi Une Shu Ito Marino Yamabe Toshio Tanaka 《Animal Science Journal》2014,85(10):915-918
To assess the stress level of cheetahs reared in Japan and to identify the prime components of the climatic conditions that affect their thermal stress, fecal corticosterone was monitored for 8 months from May to the following January. A total of 203 fecal samples were gathered in the morning from seven adult cheetahs that were kept at a zoological garden in Wakayama, Japan. Cheetahs were on exhibit singly or together with a harmonious conspecific during the day, but housed singly at night. Although the monthly fluctuation in corticosterone concentrations was not significant, the concentrations were relatively low during the summer season. Individual differences among cheetahs and the interaction effect between individual and month on the corticosterone concentrations were significant. Whereas the corticosterone concentrations negatively correlated with air temperature, they were positively correlated with the amount of rainfall. The highest air temperature and the amount of rainfall were extracted as the prime factors affecting corticosterone concentrations. These results suggest that cheetahs reared in Japan are somewhat subjected to thermal stress, particularly on cooler and/or rainy days. 相似文献
39.
A total of 39 Holstein cattle were grazed in tracts of wild grassland on account of shortage in pasture grass. Twenty-nine cattle were affected and 26 of them died during a 21-day period. The main signs were depression, anorexia, ascites, and oliguria. There was elevated serum urea nitrogen and sugar and protein in the urine. Pathological examination revealed turbid swelling of the kidney, an increase in the amount of fluid in the body cavity, edema in the perirenal adipose tissue and hemorrhage in various visceral organs and tissues. Histologically, acute tubular necrosis in the kidney, hypoplasia of the erythroblast series in the bone marrow, atrophy and degeneration of the lymphatic tissue and focal necrosis of the liver were observed in many of the cattle. Among cows experimentally fed Narthecium asiaticum Maxim., Polygonum sachalinense Fr. Schum., and Vitis coignetiae Pulliat which were presumed to have been ingested in large amounts by grazing cattle in the field, the cows fed N. asiaticum revealed the clinical, biochemical and pathological changes similar to those noticed in naturally affected cattle. Cows fed P. sachalinense and V. coignetiae showed no distinct systemic symptoms except transient anorexia and hypothermia. 相似文献
40.
Rabies is an enzootic viral disease widespread throughout the world. Although it is a vaccine-preventable disease, the annual number of human deaths caused by rabies is estimated to be 32,000 in Asia. Phylogenetic analysis based on sequence data of the partial N gene of rabies viruses in Asia has shown that the viruses are divided into five genogroups, distributed in Middle East, South Asia, South East Asia, Malay, and Arctic regions. The genetic relationships among these rabies viruses agree basically with the results of previous studies. Meanwhile, new types of vaccines are being developed by applying gene manipulation techniques to rabies virus in order to overcome the disadvantages of current vaccines. This article reviews the molecular epidemiology of rabies in Asia and progress made in the development of new-generation rabies vaccines with the goal of elimination or control of rabies in Asia. 相似文献