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71.
The salt and water balances at Konanki pilot area in Nagarjunasagar project right canal command in Andhra Pradesh State of India were analysed using SALTMOD. The model was calibrated by using two-year data collected in the pilot area. From the calibration, the leaching efficiencies of the root and transition zone were estimated as 65% and the out going natural sub-surface drainage was determined as 50 mm per year. The model predicts that the root zone soil water salinity will be reduced to 4, 3 and 2.5 dS/m (from an initial value of 11.5 dS/m) during the first, second and third seasons within six years after installation of the drainage system. Next, the situation prior to the installation of the drainage system was reconstructed using the model. Finally, sensitivity analyses were made to study the effects of varying drain depth, spacing and amount of irrigation water applied on root zone salinity and depth to water table. Here, the model predicted that closer than the present spacing or further deepening of the drains from the present depth of 1 m to 1.4 m will not have any better influence on the reduction of the root zone salinity than in the present situation. These simulations also suggested that by applying 80% of the present amount of irrigation water, the root zone salinity can be brought down to 5 and 4 dS/m by second and fourth years, respectively and this will in turn reduce the problem of water logging and salinity to some extent.  相似文献   
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An ecological community's species diversity tends to erode through time as a result of stochastic extinction, competitive exclusion, and unstable host-enemy dynamics. This erosion of diversity can be prevented over the short term if recruits are highly diverse as a result of preferential recruitment of rare species or, alternatively, if rare species survive preferentially, which increases diversity as the ages of the individuals increase. Here, we present census data from seven New and Old World tropical forest dynamics plots that all show the latter pattern. Within local areas, the trees that survived were as a group more diverse than those that were recruited or those that died. The larger (and therefore on average older) survivors were more diverse within local areas than the smaller survivors. When species were rare in a local area, they had a higher survival rate than when they were common, resulting in enrichment for rare species and increasing diversity with age and size class in these complex ecosystems.  相似文献   
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In this study, we demonstrate the antibacterial activity of P128 on Staphylococcus isolates responsible for canine pyoderma. Eighty seven swabs were collected from dogs suffering from pyoderma and subjected to antibiotic sensitivity test and 46 Staphylococcus strains were isolated and characterized. In-vitro antimicrobial susceptibility testing with P128 was done by Minimum Inhibitory Concentration (MIC) method as per CLSI guidelines. All the Staphylococci isolated from the dogs with pyoderma, although showed resistance to various antibiotics tested, were lysed by P128. Clinical efficacy of P128 was examined in 17 dogs with pyoderma by application of the P128 hydrogel twice daily for 8 days and the results indicated complete healing of all the lesions of all the dogs under treatment. Under the conditions of this study, P128 was found to be a potent convenient proteinaceous drug for the treatment of staphylococcal pyoderma in dogs.  相似文献   
76.
The aim of the present study was to examine the role of oxytocin (OT) in the progesterone (P4) and prostaglandins (PGs) pathway to induce oocyte meiotic resumption. Cumulus–oocyte complexes were co‐cultured with follicular hemisections for 15 h to determine the effects of different doses of OT or atosiban (ATO; oxytocin receptor antagonist) on oocyte meiotic resumption. In another experiment, we examined the effect of the interaction between P4, OT and PGs on the regulatory cascade of the oocyte meiotic resumption. Oxytocin at 1 μm was effective in inducing meiotic resumption in oocytes co‐cultured with follicular cells (84.0%), not differing from the positive control group (74.4%). Atosiban inhibited in a dose‐dependent manner the positive effect of OT on the meiotic resumption (27.6% metaphase I with 10 μm of ATO, which did not differ from the 25.5% of the negative control group). Furthermore, a third experiment showed that P4 was able to induce oocyte meiotic resumption, which was inhibited by ATO. However, the OT positive effect was not blocked by mifepristone (P4 antagonist), but was inhibited by indomethacin (a non‐selective PTGS2 inhibitor). Collectively, these data suggest a sequential role of P4, OT and PGs in the induction of oocyte meiotic resumption.  相似文献   
77.
动物疫苗及其合理使用(一)   总被引:2,自引:0,他引:2  
疫苗接种是预防动物传染病发生的重要举措。依据免疫学理论,疫苗作为抗原,通过激发动物机体免疫系统,产生特异的体液免疫和细胞免疫,从而获得针对某种疾病的特异性免疫。疫苗一般分为细菌疫苗、病毒疫苗和类毒素疫苗等。用于防病治病的各种疫苗、菌苗又是特殊的生物药品,与普通化学药品具有完全不同的成分、功能和特性,疫苗中含有多种蛋白质(除细菌或病毒外,有的还含有保护剂、鸡胚尿囊液或细胞培养液),它们均适合许多病原体的生长,有些制品还是活的微生物,一旦污染后果不堪设想。疫苗在保存、运输和使用时有其特别要求。如果方法不当,不但会使活性物质失活,起不到免疫防病作用;而且还可能适得其反,引发动物新的疾病,造成重大损失。  相似文献   
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79.
Experiments conducted during 1981/82 and 1983/84 in a tobacco nursery showed that the male moth catch ofSpodoptera litura F. was significantly higher in pheromone traps 2.0 m above ground level, than at lower or higher elevations.  相似文献   
80.
During mating, the male ofSpodoptera litura F. (Noctuidae: Lepidoptera) deposits a portion of the secretions from the primary simplex into the bursa of the female, after which the simplex becomes flaccid. Subsequently, the secretions in the primary simplex remain either colorless or light yellow. The newly mated males can not be differentiated from 0- or 1-day-old virgins, as the color of the simplex is quite similar in both cases. In such situations the width of the simplex can be used as a quantitative character to differentiate mated males from virgins. In laboratory studies, the width of the primary simplex was found to be less than 435 μm in 96.7% of mated males, whereas it was more than 451 μm in 94.65% of virgin males. The percentage falling in the range of 435-451 μm is only 3.31 and 5.35 in mated and virgin males, respectively. In the trapped males also, the percentage of males with this range is only 8.63.  相似文献   
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