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81.
This study was conducted to evaluate the effect of ethanolic extract of propolis (EEP) on growth performance and plasma biochemical
parameters of rainbow trout (Oncorhynchus mykiss). Graded levels of EEP [0 (control), 1, 2, and 4 g kg−1 diet] were fed to trout juveniles (mean weight 7.73 ± 0.17 g) for 10 weeks. Dietary EEP supplementation regardless of inclusion
level significantly improved the specific growth rate of fish. Similarly, supplemental EEP generally improved the feed efficiency
ratio and protein efficiency ratio, but no significant differences were observed between the 1 g kg−1 EEP group and the control group. In addition, dietary EEP supplementation generally increased the plasma superoxide dismutase,
lysozyme, total antioxidant capacity, glutathione peroxidase, and catalase activities, but decreased the plasma malondialdehyde
level. The plasma triglycerides level was significantly lower in the 1 or 4 g kg−1 EEP group as compared with the control group. Dietary EEP supplementation generally decreased the plasma aspartate aminotransferase
and alanine aminotransferase activities, but increased the hepatic aspartate aminotransferase and alanine aminotransferase
activities. These results indicate the potential to use the EEP as a growth promoter, hepatoprotective agent, and immunostimulant
for rainbow trout. 相似文献
82.
The effect of understory removal on microclimate and soil properties in two subtropical lumber plantations 总被引:1,自引:0,他引:1
Understory vegetation is an important component in forest ecosystems. However, the effects of understory on soil properties in subtropical forests are not fully understood. We thus conducted an experimental manipulative study in two young fast-growing plantations—Eucalyptus urophylla and Acacia crassicarpa—in southern China, by removing understory vegetation in both plantations, to estimate the effects of understory vegetation on microclimate, soil properties and N mineralization. Our data showed that, after 6 months, understory removal (UR) in both plantations had greatly increased soil surface luminous intensity (90–500 cd) and temperature (0.5–0.8 °C); soil moisture was reduced in the Eucalyptus plantation but not in the Acacia plantation. Understory removal also reduced soil organic matter (SOM), but had little impact on other soil chemical properties, including total phosphorus, C/N, pH, exchangeable cations (K, Ca, Mg), available P, ande extractable NH4–N and NO3–N. We found a significant decline of soil N mineralization and nitrification rates in the 0–5 cm soils of UR in both plantations. The decline of SOM in UR may contribute to the lower N transformations rates. This study indicates that a better understanding of understory vegetation effects on soil N cycling would be beneficial to forest management decisions and could provide a critical foundation for advancing management practices. 相似文献
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The UV curing reaction of the difference between allyl abietate(AA) and allyl isopimarate(AI) was studied. The conversion rate of the vinyl double bond was characterized and detected by FT-IR analysis. Results showed that conversion of double bonds are firstly increased then decreased with the increases of the dosage of initiators. Conversion of double bonds firstly increased and then leveling off with the increases of the illumination time, and AA is higher before the 200 s. AA is higher then AI under the same illumination intensity. Surface drying time of AA is shorter than AI, and relative curing speed become faster at the same conditions. Under the conditions of 2-hydroxy-2-methylpropiophenone(Darocure-1173)as photo initiator and dosage 6%, illumination time 200 s, illumination distance 4.5 cm and illumination intensity 100%, number average molecular weight of cure products of AA and AI are 4 176 and 9 407 with polymerisation degrees of 12 and 28, respectively. The obtained UV cured coating all have smooth and transparent appearance. It represented some superior properties in flexibility, mechanical impact strength, adhesive power, hardness, acid resistance, alkali resistance, salt resistance, water resistance, etc.. The hardness of AA and AI cured products are H and HB, respectively. 相似文献
85.
虾池沉积物中3类主要细菌的垂直分布特征 总被引:1,自引:0,他引:1
采用平板涂布法和MPN法测定了虾池底质下 0到 30cm深度范围内 3类主要细菌类群的垂直分布情况。结果表明 ,底泥中细菌主要集中于 0到 5cm的表层范围内 ,随深度增加 ,数量急剧减少 ,至 30cm深处所测到菌量已很少。底泥中的总菌量随养殖时间推移 ,逐渐增加 ,到养殖中后期 ,表层菌量增加至 10 6CFU/g ,表层以下 10~2 0cm的总异养菌量和硝酸盐还原菌数量也增加至 10 5CFU/ g以上。弧菌仍集中于表层。细菌的垂直分布主要受各层有机物和溶解氧含量的影响 相似文献
86.
稻瘟病菌(Magnaporthe oryzae)共有11个假定的Rab蛋白家族成员,本文选取了MoYpt51(MGG_06241)和MoYpt52(MGG_01185)进行了生物信息学分析。通过搜索多个大型蛋白互作数据库和文献,共得到数百个与核心蛋白互作的蛋白和互作对。利用信息处理技术和高效制图平台将这些蛋白互作对构建成互作网络,得到若干个具有生物学意义的模块。结果表明,筛选得到的互作蛋白中,有的参与了蛋白降解的泛素途径(MGG_04053等)、囊泡介导的蛋白胞内运输(MGG_01238等),有的在蛋白、染色体的组装和修饰等过程(MGG_03677等)起重要作用。大部分假定互作蛋白定位于细胞质和质膜上,为其与目标蛋白互作提供了空间可能性。 相似文献
87.
植被恢复和覆土厚度对砒砂岩区土壤水分及养分的影响 总被引:1,自引:0,他引:1
[目的]研究植被恢复对砒砂岩区土壤水分和养分的影响状况,明确对于砒砂岩地区土壤保水保肥效果最佳的植被恢复类型,为砒砂岩区的生态修复和区域水土流失治理提供理论依据。[方法]选取准格尔旗暖水乡裸露砒砂岩向覆土砒砂岩过渡区域,以黄土—砒砂岩交界带不同人工恢复植被和自然恢复草地的土壤为研究对象,测定土壤水分和养分含量,分析不同植被恢复和覆土厚度对砒砂岩区土壤水分和养分特征的影响(其中天然草地作为对照)。[结果](1)裸露砒砂岩向覆土砒砂岩过渡区域土壤水分含量主要受黄土厚度影响,黄土的持水性能优于砒砂岩土壤,养分含量主要受植被恢复类型影响;(2)研究区土壤各指标均属于中等变异程度,其中土壤水分、碳、氮含量自北向南随覆土厚度增加逐渐增加,磷素分布则相反;(3)对比天然草地,沙棘和油松恢复对砒砂岩区土壤碳、氮含量的提升效果最好,土壤有机质含量分别提高了43.12%和34.27%,全氮提高了78.95%和42.11%,铵态氮提高25.64%和46.15%,硝态氮提高69.44%和42.22%。其中油松恢复下土壤水分含量高于天然草地54.55%,但人工植被恢复后的土壤磷素水平并没有提升。[结论]黄土较砒... 相似文献
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90.
在众多的数据挖掘算法中,贝叶斯算法因为准确性高,运算性能强而得到广泛应用。利用日常生活中的例子深入浅出的阐述了贝叶斯算法的基本原理,并应用SQL Server 2005数据挖掘工具,对2009年收集的农安地力评价的数据进行了分析,同时应用贝叶斯算法对地力等级进行了预测。 相似文献