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1.
Genome‐wide association mapping for complex traits in cattle populations is a powerful, but expensive, selection tool. The DNA pooling technique can potentially reduce the cost of genome‐wide association studies. However, in DNA pooling design, the additional variance generated by pooling‐specific errors must be taken into account. Therefore, this study aimed to investigate factors such as: (i) the accuracy of allele frequency estimation; (ii) the magnitude of errors in pooling construction and in the array; and (iii) the effect of the number of replicate arrays on P‐values estimated by a genome‐wide association study. Results showed that the Illumina correction method is the most effective method to correct the allele frequency estimation; pooling errors, especially array variance, should be taken into account in DNA pooling design; and the risk of a type I error can be reduced by using at least two replicate arrays. These results indicate the practical capability and cost‐effectiveness of pool‐based genome‐wide association studies using the BovineSNP50 array in a cattle population.  相似文献   
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Femoral trochleoplasties resurfaced with autogenous free periosteal grafts in six dogs were compared to femoral trochleoplasties performed without grafts in six dogs. The grafts produced cartilage as early as 4 weeks after surgery; however, it was fibrocartilage rather than normal hyaline articular cartilage. The trochleoplasties not resurfaced with periosteum also healed with fibrocartilage but not until 40 weeks postoperatively. The grafted stifles had less patellar cartilage damage when compared to trochleoplasties left to heal without resurfacing.  相似文献   
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Tillage for the "complete inversion" of soil, that is, overturning soil slices 180° was proposed, a "spot plow" was developed and tested to accomplish the task, and a simulation model was evaluated to demonstrate the efficacy of the plow on weed control. A 360 mm wide spot plow was designed to operate at a speed of 1.9 m s−1 for the spot plowing with the least possible lateral displacement of the soil slice by utilizing the inertia of the soil slice and securely rotating it. In field experiments, complete spot inversion required an operating speed of at least 1.6 m s−1; at lower speeds, a portion of the soil block was left half-inverted and further lowering led to considerable lateral displacement. The displacement in the forward and lateral directions was minimal, implying that spot plowing is suitable for potential application to and verification of the weed population dynamics model in the field. A simple linear matrix model of the population dynamics of annual weeds was proposed, whereby four layers of soil were set to describe tillage and other ecological events. The effect of tillage on weed control was evaluated by the equilibrium reproduction rate allowed to sustain a stable population of weeds. The simulation model showed that alternately changing the depth of spot plowing had a significant effect on controlling weeds of low-survival-rate seeds, even when some incomplete inversion of the soil slice was taken into account.  相似文献   
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The abundance and stomach contents of salmonids (Oncorhynchus spp.) and the biomass of prey organisms were examined in the central subarctic Pacific and Bering Sea in the summer of 1991 and 1992. Salmonids were caught by surface longline using the same level of fishing effort. Chum (O. keta) and pink (O. gorbuscha) salmon were the predominant species, representing 44% and 36% sof the total catch (n = 1275) in 1991. In 1992, chum salmon composed 85% of the total catch (n = 603), but the catch of pink salmon decreased to 1% of the total catch due to the odd/even year fluctuation of Asian pink salmon abundance in the study area. It was found that chum salmon changed their dominant diet from gelatinous zooplankton (pteropods, appendicular-ians, jellyfishes, chaetognaths, polychaetes and unidentified materials) in 1991, when pink salmon were abundant, to a diet of crustaceans (euphausiids, cope-pods, amphipods, ostracods, mysids and decapods) in 1992, when pink salmon were less abundant. Local crustacean biomass (wet weight; mg m-3) had significant negative correlation with the CPUE (catch number per 30 hachi) of pink salmon in 1991 (r = -0.586; P = 0.026) and that of chum salmon in 1992 (r =–0.616; P = 0.014). There may be a limitation in the available prey resource for production of salmonids.  相似文献   
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Gene expression was compared under favorable germination conditions between dormant and non-dormant seeds of rice paddy Echinochloa weeds and a domesticated Echinochloa species lacking dormancy. Two dormancy-specific cDNAs, Ecd1 and Ecd2 , were identified by differential display. Northern blot analysis revealed that these genes were more strongly expressed in dormant seeds than in non-dormant seeds. A database search for the Ecd1 sequence revealed no significant homology with any known proteins, but the Ecd2 sequence was highly homologous with the α-chain of mitochondrial H+-transporting adenosine triphosphate (ATP) synthase in rice ( Oryza sativa L.). These findings indicate that the gene encoding the enzyme associated with conventional aerobic respiration is more abundantly transcribed in dormant seeds. The results reported in the present study suggest that dormant seeds of paddy Echinochloa weeds, which appear during the period when paddy soil becomes aerobic by drainage, may maintain viability primarily by efficient conventional aerobic respiration, including ATP synthesis catalyzed by the mitochondrial H+-transporting ATP synthase.  相似文献   
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REIJI  MASUDA  JUN  SHOJI  MITSUHIRO  AOYAMA  MASARU  TANAKA 《Fisheries Science》2002,68(2):320-324
ABSTRACT: Developmental changes of swimming speed were analysed in the chub mackerel Scomber japonicus raised on two distinct dietary regimens. One group was fed only zooplankton such as rotifers and Artemia nauplii (R group) and the other group was fed rotifers plus red sea bream Pagrus major larvae (Pm group). Fish from the Pm group grew faster than those from the R group, and both the cruise and burst swimming speeds were faster for the Pm group even when match-sized comparisons were made. Fish in the Pm group attained a standard length (SL) of 17.5 mm by day 14 and their cruise and burst swimming speeds were 5.39 SL/s and 18.45 SL/s, whereas the R group attained 17.35 mm SL by day 17 and their cruise and burst swimming speeds were 4.28 SL/s and 13.98 SL/s. The results suggest that the swimming speed of chub mackerel in the wild would develop differently depending on the food resources they happen to encounter.  相似文献   
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Following an "over-the-top" reconstruction of the cranial cruciate ligament using fascia lata and the lateral one-third of the patellar ligament, joint instability was measured using an in vitro laxity testing device. Cranlocaudal drawer increased between zero and four weeks, then returned to initial values at 26 weeks.  相似文献   
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