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In order to control rates of response and inbreeding, mate selection using fuzzy selective mating criteria (FMC) was investigated in adult multiple ovulation and embryo transfer nucleus schemes for dairy cattle. Stochastic simulation was used to model the closed nucleus scheme. This mate selection was examined in four alternative mating and male selection schemes: (i) a hierarchical scheme; (ii) a hierarchical sibship scheme (two males per sibship); (iii) a factorial scheme (two sires per dam); and (iv) a factorial sibship scheme (two males per sibship and two sires per dam). Genetic response and inbreeding rate tended to be reduced by increasing the trade-off parameter of FMC between the expected breeding value and inbreeding of progeny. Inbreeding rates in all schemes were reduced by reducing the variance of family size through selection and the average coancestry of mating pairs through mate allocation.  相似文献   
3.
A Cucumber mosaic virus was newly isolated from Silene armeria and was characterized by biological, serological and molecular biological methods. Received 4 July 2001/ Accepted in revised form 28 August 2001  相似文献   
4.
Colonic mucosal mast cells are implicated in the pathogenesis of visceral hypersensitivity associated with irritable bowel syndromes. This study was designed to investigate the roles of mucosal mast cells in development of an experimental visceral hypersensitivity induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in rats. TNBS, when injected into the proximal colon through laparotomy, produced a significant decrease in pain threshold of the distal colon to mechanical distention, indicating a visceral hypersensitivity. In the proximal colon that was directly insulted by TNBS, mucosal necrosis and extensive inflammatory cell infiltration were observed with concomitant increase in tissue myeloperoxide (MPO) activity. In the distal colon where distention stimuli were applied, the number of mucosal mast cells significantly increased following TNBS treatment, although neither mucosal injury nor increase in tissue MPO activity was observed. In an organ culture, spontaneous release of a mucosal mast cell-specific protease (RMCP-2) from the distal colon tissue of TNBS-treated rats was significantly larger than that of sham animals. Furthermore, TNBS-induced visceral hypersensitivity was significantly suppressed by subcutaneous pretreatment with a mast cell stabilizer doxantrazole in a dose-dependent manner. These findings suggest that prominent colonic mast cell infiltration associated with an enhanced spontaneous mediator release is responsible, at least partly, for development of visceral hypersensitivity induced by TNBS in rats.  相似文献   
5.
Sakhalin taimen Hucho perryi populations have decreased drastically to near extinction. It is urgent to establish an effective conservation strategy based on an understanding of the characteristics of migration and habitat use of this species. We examined the migration history of anadromous Sakhalin taimen captured off the Sarufutsu coast, northern Hokkaido, Japan, using otolith Sr:Ca ratios and also examined the relationship between their otolith Sr:Ca ratios during freshwater and seawater residence in a rearing experiment. Otolith Sr:Ca ratios of some fish from the Sarufutsu coast showed freshwater levels (0.5–4.0 × 10−3) near the core, which thereafter increased to brackish water levels (4.0–6.0 × 10−3), and then to seawater levels (6.0–10.0 × 10−3) in the outermost regions. Those findings indicate that specimens from the Sarufutsu coast migrated to the brackish water region or the sea and spent most of their lives there. The anadromous migration pattern including the timing of downstream migration seems to be flexible among individuals in the species. They migrate between freshwater and seawater or brackish water several times during their lives, showing extensive habitat use. It is essential to secure the continuity among the freshwater, brackish water, and seawater areas for their effective conservation.  相似文献   
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In this study, the durability of wood-based panels was evaluated by comparing the internal bond (IB) strength retention after five different laboratory-based accelerated aging tests with the IB retention after 5 years of outdoor exposure in Shizuoka City. In each accelerated aging test, the IB retention of MDI-bonded panels showed high retention compared to other panels. Outdoor exposure in Shizuoka City resulted in an IB retention value for particleboard (PF) and oriented strandboard (aspen) of less than 10% after the 5-year exposure period. Medium-density fiberboards maintained their initial IB strength over the same period. Calculation of the mean IB retention for all board types allowed comparison of the severity of aging between the accelerated test methods and outdoor exposure. The ASTM six-cycle test method was the most severe among the standard treatment cycles applied.  相似文献   
8.
In the present study, the daily excretion of potassium (K) in urine (urinary K(UK)) was estimated from a 6 h urine sample using urinary creatinine (UC) as the index substance. All urine was collected from six pregnant Holstein cows at 6 h intervals for 24 h on 3 days of the 4th, 2nd and final week before the expected date of parturition. In total, 72 6 h urine samples were obtained. Daily UC excretion (mg/day per kg bodyweight (BW)) was almost the same for the three sampling days. Daily UC excretion varied among cows from 22.1 to 24.3 mg/day per kg BW with a mean of 22.8 mg/day per kg BW with no significant difference. Thus, daily UC excretion was confirmed to be constant throughout the prepartum period with no differences among individuals. The concentration ratios of K to creatinine ((UK mg/dL)/(UC mg/dL) (UK/UC)) correlated strongly to the hourly K excretions (mg/h per kg BW) (r = 0.952, P < 0.01) in the 6 h urine samples. The differences in the UK/UC ratio between sampling periods were not significant within each cow. Therefore, daily UK excretion (mg/day) can be estimated using the equation: daily UK excretion (mg/day) = daily UC excretion (mg/day per kg BW) × BW (kg) × 6 h urine sample UK/UC, where daily UC excretion can be a given value.  相似文献   
9.
Phylogenetic analysis of sugarcane rusts based on sequences of ITS and the 5.8 S rDNA revealed two highly divergent ITS groups among isolates of Puccinia sp. sensu Muta, 1987 and P. kuehnii specimens. Although there is sufficient divergence (exceeding normal intraspecific variation) between the ITS regions of the two groups to support separation into different species, unusually high homology of the ITS group I sequences with those of members of Cronartium and identical sequences of the D1/D2 regions of the LSU rDNA for all the isolates of “Puccinia sp.” and P. kuehnii that otherwise exhibited different ITS sequences, suggest that the two highly divergent sequences may have resulted from abnormal genetic events leading to non-orthologous, intraspeciflc polymorphisms. The other sugarcane rust, P. melanocephala and the grass rusts, P. miscanthi and P. rufipes, were separated from “Puccinia sp.” and P. kuehnii and from each other in D1/D2 region analyses, indicating that D1/D2 region sequences may more correctly reflect phylogenetic relationships in these rusts than do the ITS regions. Further studies to examine differences in patho-genicity or finer morphological features within P. kuehnii that may be correlated with the high divergence in ITS sequences and experiments to determine if these two sequence types represent intraspeciflc polymorphism are necessary. Received 11 October 2000/ Accepted in revised form 24 November 2000  相似文献   
10.
Basidiocarps of the violet root rot fungus, Helicobasidium mompa, are less frequently used for isolation than are mycelial strands and sclerotia even though the basidiocarps are conspicuously produced at the trunk base of diseased plants. Basidiocarps are also more suitable for storage. This paper describes an improved method for obtaining pure cultures from basidiocarps using microcentrifuge tubes to facilitate the awkward steps of rinsing fungal materials under a dissecting microscope. Received 28 June 2000/ Accepted in revised form 4 August 2000  相似文献   
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