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11.
Rivero JC Inoue Y Murakami N Horii Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(6):519-521
The effects of host age and sex on susceptibility to Strongyloides venezuelensis in Wistar rats were examined by counting larvae recovered from the lungs of animals 3 days after infection. The susceptibility of female rats to S. venezuelensis rapidly decreased with age and elevated estrogen. Resistance in female rats inoculated at 6 and 10 weeks of age was nine and twenty-fold higher, respectively than that in the youngest group (3 weeks). In contrast, the susceptibility of male animals was lowest in the youngest group, then increased with age and elevated testosterone. Sex differences in susceptibility were not evident in the youngest group, but became apparent with age. 相似文献
12.
Nakagawa K Takemura N Machida N Kawamura M Amasaki H Hirose H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(7):619-621
A spayed female mixed cat (case 1) and its female offspring, the result of a pairing between case 1 and its male sibling, were diagnosed with hypertrophic cardiomyopathy (HCM). A pedigree survey revealed that the prevalence of HCM was at least 12.5% in the family, which was considered to be significantly higher than that in a hospital-based population (approximately 1.6%). Thus, this finding seems to support the suspected occurrence of familial HCM in this group of related cats. 相似文献
13.
Rivero JC Inoue Y Murakami N Horii Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(6):457-461
The effects of male and female sex hormones on the protective capacity of Wistar rats against infection with Strongyloides venezuelensis were investigated. Male rats were more susceptible than females in terms of worm recovery from the lungs. Orchidectomy of male animals significantly reduced the plasma testosterone concentration and increased host resistance to the migratory stages of S. venezuelensis larvae. In contrast, ovariectomy of female animals significantly decreased host resistance in association with a significant reduction of estrogen levels. To examine the direct effect of sex hormones, exogenous testosterone and estrogen were implanted into animals. Susceptibility significantly increased or decreased in ovariectomized females given testosterone or estrogen, respectively. These results suggest that male and female sex hormones are important in the down- and up-regulation of host resistance against S. venezuelensis in Wistar rats. 相似文献
14.
内蒙古中东部野生扁蓿豆种子硬实性的研究 总被引:1,自引:0,他引:1
扁蓿豆是抗逆性极强的优良牧草,但其种子发芽率低,具有65 %~75 %的硬实。在恒温25℃时发芽率较高,在变温20 ~30℃时发芽率最高,若温度超过30℃或低于15℃时发芽被抑制,但短时间高温处理有利于促进发芽。采用机械或浓硫酸处理,发芽率分别比对照高40.6 %和45.6 %。野生种子的硬实率与采集地气温,特别是与7月份温度有着很高的正相关关系,而且不同产地的种子表现出较大的差异,以赤峰市北部采到的居群硬实率最高,比呼和浩特市采集的居群高9 %。随着储藏年限的推移,种子的硬实率不断下降,发芽率增加,储藏3.5年的种子发芽率达到了67.0 %,表明扁蓿豆种子采集后通过室温储藏可以达到提高发芽率的效果。 相似文献
15.
Journal of Plant Diseases and Protection - The antagonistic rhizobacterium, Pseudomonas fluorescens strain LRB3W1, controls cabbage Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans... 相似文献
16.
Kraft pulp bleaching effluent supplemented with glucose was decolorized by a newly isolated fungusGeotrichum candidum Dec 1 (Dec 1) that showed a wide decolorizing spectrum to synthetic dyes. When the glucose concentration in the effluent was 30 g/l, the color removal and the reduction of absorbable organic halogens were 78% and 43% after 7 days culture, respectively. The average molecular weight of colored substances measured by gel filtration chromatography was lowered to less than 3000 from 5600 after 7 days culture. As the contribution of extracellular enzymes such as peroxidase (DyP), manganese peroxidase, and laccase to the decolorization of the kraft pulp bleaching effluent was small, Dec 1 appears to have a different mechanism of decolorizing kraft pulp bleaching effluent when compared with enzymes used to decolorize synthetic dyes. 相似文献
17.
In Japan, the lifetime cycle of most housing lasts around 20–30 years. A governing factor in this respect is poor durability
due to old-fashioned use of the house. As a solution of this problem, houses can be built with a skeleton structure that allows
free partition of spaces by future owners. To develop the skeleton structure effectively, multistory frames with spans of
6 to 10 m are required. For this reason, attention has been focused on the behavior of multistory timber frame structures.
In this article, two types of wooden portal frame structures are proposed. Both structures have improved vertical columns
with short horizontal members glued in. The aim of this study was to investigate structurally effective solutions with these
types of columns. The first type of the new structure changed the location of the moment-transmitting ductile connection with
the improved columns. The second type of structure used an extended panel zone. Nine portal frame specimens were tested. The
stiffness values were improved by around 1.7 and 3.5 times when compared with the control, and the strength was improved by
around 1.25 and 1.45 times. 相似文献
18.
Spatially distributed morphological characteristics of macropores in forest soils of Hitachi Ohta Experimental Watershed, Japan 总被引:1,自引:0,他引:1
Shoji Noguchi Yoshio Tsuboyama Roy C. Sidle Ikuhiro Hosoda 《Journal of Forest Research》1997,2(4):207-215
Morphological characteristics of macropores in forest soil profiles were investigated at Hitachi Ohta Experimental Watershed
in Japan. Nine individual profiles at different locations (various spatial scales in a catchment) and twenty profiles at one
site (a small spatial scale) were excavated to the bedrock to investigate density, origin, diameter, direction, and gradient
of macropores. Macropore densities in a soil profile ranged from 3.5 to 29.1 per m and from 5.4 to 75.1 per m2, respectively. Subsurface erosion, root channels, and interactions between subsurface erosion and root channels accounted
for 36.9, 36.5, and 19.0%, of the described macropores. The mean macropore diameter in organic-rich soil layer (17–20 mm)
was larger than in the B horizon (11–14 mm) at both spatial scales. The dominant gradients of all macropores in the organic-rich
soil layer and B horizon were at negative oblique angles. Approximately 90% of the macropores in the organic-rich soil layer
and approximately 80% of the macropores in the B horizon fell within the range between −50 and 50 degree planar direction.
Subsurface flow and root systems are believed to play important roles in determining the morphological characteristics of
macropores. These characteristics appear to have variable influences in different soil horizons rather than at different spatial
scales.
A part of this paper was presented at the 103th (1992) and 105th (1994) Annual Meetings of Japanese Forestry Society. 相似文献
19.
Tomo’omi Kumagai Koichiro Kuraji Hironori Noguchi Yuri Tanaka Katsunori Tanaka Masakazu Suzuki 《Journal of Forest Research》2001,6(4):257-264
Environmental factors, such as global solar radiation, wind speed, air temperature, humidity, and CO2 concentration, were measured above and within the canopy of a tropical rainforest in Lambir Hills National Park, Sarawak,
Malaysia. Few data concerning the environment of this forest have been reported. Intensive observations were carried out in
1998, 1999, and 2000 with the following results: (1) The fraction of global solar radiation reaching the upper layer of the
canopy varied with global solar radiation above the canopy. Even though the global solar radiation above the canopy fluctuated,
the fraction of that reaching the lower canopy and the ground was constantly approximately 5%. (2) The fraction of wind speed
reaching each layer of the canopy increased with wind speed above the canopy. Little wind was usually present at the lower
canopy. (3) The daytime air temperature at the canopy top was higher than that near the ground. The maximum difference between
the air temperature at the canopy top and that at the ground was about 5°C, and the diurnal temperature ranges at the canopy
top and those at the ground were about 8°C and about 5°C, respectively. The highest daytime water vapor pressure occurred
within the canopy and particularly near the ground. Vertical gradients of water vapor pressure during the day were steep,
probably because of high transpiration. (4) In the 1998 observation the minimum and the maximum CO2 concentrations were 360 ppm in the day and 450 ppm at night, while in the 2000 observation the minimum and the maximum CO2 concentrations were 350 ppm in the day and 540 ppm at night. The higher CO2 concentration in the daytime and the lower concentration at night observed during the 1998 observation period were probably
due to reduced photosynthesis and soil respiration caused by exceptional dry conditions during the observation period. 相似文献
20.
Summary The acoustic emissions (AEs) under partially compression were monitored with two softwood and one hardwood specimens in very eary stages of decay by a brown- and a white-rot fungus. Even slightly decayed specimens emitted AEs immediately after beginning of loading, typically when partial compression stress was applied to brown-rotted wood with the flat-headed attachment. With sound specimens of three wood species, only a few AEs were generated until the load reached at the proportional limit. These results suggest that AE monitoring will be one of the feasible means to detect the incipient stages of decay in a field test.The authors thank the Weyerhaeuser Research Grants Program for its aid in this investigation 相似文献