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61.
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
62.
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
63.
Kent MORI Satoshi SUZUKI Daisuke KOYABU Junpei KIMURA Sung-Yong HAN Hideki ENDO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(5):571-578
Although the sea otter (Enhydra lutris) is a complete aquatic species,
spending its entire life in the ocean, it has been considered morphologically to be a
semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and
functional adaptations of E. lutris in comparison to other Mustelidae
species. We compared muscle mass and bone measurements of five Mustelidae species: the sea
otter, Eurasian river otter (Lutra lutra), American mink
(Neovison vison), Japanese weasel (Mustela itatsi) and
Siberian weasel (M. sibirica). In comparison with the other 4 species,
E. lutris possessed significantly larger gluteus, popliteus and
peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may
act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the
fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle
of E. lutris were fused with those of the tensor fasciae latae muscle and
gluteofemoralis muscles, and they may play a role in femur abduction. These results
suggest that E. lutris uses the abducted femur, medially rotated crus,
eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful
propulsion generator. Therefore, we conclude that E. lutris is a complete
aquatic animal, possessing differences in the proportions of the hindlimb muscles compared
with those in other semi-aquatic and terrestrial mustelids. 相似文献
64.
Ayano OMURA Wataru ANZAI Daisuke KOYABU Hideki ENDO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(9):1043-1048
Clarification of the trunk structure in Urodela is important in understanding the
locomotive evolution of basal tetrapods. The components of the muscular trunk wall among
Urodela using different modes of locomotion were compared. Since the whole trunk may be
used for swimming and the effect of limbs may be small in the more aquatic species, they
showed smaller differences in the trunk muscles among anterior, middle and posterior
sections of the trunk. By contrast, in the more terrestrial species, the dorsal and
abdominal muscles are larger in the middle section than those in the anterior and
posterior sections. High compressive stresses occur in the supporting limbs and their
insertion at the trunk on the ventral side, and spread from the forelimbs along the back
to the supporting hindlimbs on the dorsal side. Tensile stresses occur in the middle
ventral part. The components of the trunk muscles among the three sections may reflect
differences in stresses occurring in the trunk of the more terrestrial species. The
findings also suggest that in the middle section, larger dorsal muscles for stiffening the
back to maintain posture and larger abdominal muscles are responsible for balancing the
body weight while it is supported by the limbs in the more terrestrial species. 相似文献
65.
Yojiro YANAGAWA Yukiko MATSUURA Masatsugu SUZUKI Shin-ichi SAGA Hideto OKUYAMA Daisuke FUKUI Gen BANDO Masashi NAGANO Seiji KATAGIRI Yoshiyuki TAKAHASHI Toshio TSUBOTA 《The Journal of reproduction and development》2015,61(1):61-66
Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation. 相似文献
66.
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
67.
68.
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
69.
70.
Noritaka ADACHI Daisuke YAMAGUCHI Akiyuki WATANABE Narumi MIURA Seiji SUNAGA Hitoshi OISHI Michiko HASHIMOTO Takatsugu OISHI Masaki IWAMOTO Hirofumi HANADA Masanori KUBO Akira ONISHI 《The Journal of reproduction and development》2014,60(2):100-105
The objective of this study was to examine the health and meat production of cloned sows
and their progenies in order to demonstrate the application of somatic cell cloning to the
pig industry. This study compared the growth, reproductive performance, carcass
characteristics and meat quality of Landrace cloned sows, F1 progenies and F2 progenies.
We measured their body weight, growth rate and feed conversion and performed a
pathological analysis of their anatomy to detect abnormalities. Three of the five cloned
pigs were used for a growth test. Cloned pigs grew normally and had characteristics
similar to those of the control purebred Landrace pigs. Two cloned gilts were bred with a
Landrace boar and used for a progeny test. F1 progenies had characteristics similar to
those of the controls. Two of the F1 progeny gilts were bred with a Duroc or Large White
boar and used for the progeny test. F2 progenies grew normally. There were no biological
differences in growth, carcass characteristics and amino acid composition among cloned
sows, F1 progenies, F2 progenies and conventional pigs. The cloned sows and F1 progenies
showed normal reproductive performance. No specific abnormalities were observed by
pathological analysis, with the exception of periarteritis in the F1 progenies. All pigs
had a normal karyotype. These results demonstrate that cloned female pigs and their
progenies have similar growth, reproductive performance and carcass quality
characteristics and that somatic cell cloning could be a useful technique for conserving
superior pig breeds in conventional meat production. 相似文献