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排序方式: 共有325条查询结果,搜索用时 15 毫秒
51.
Healthy and comfortable dormitory environment has a major impact on students daily life. Indoor thermal environment parameters and CO2 concentration of typical student dormitories under natural ventilation during cold spell was studied through a 29-day co 相似文献
52.
Zhi-Qiang Chen Karl Lundén Bo Karlsson Ingrid Vos Åke Olson Sven-Olof Lundqvist Jan Stenlid Harry X. Wu María Rosario García Gil Malin Elfstrand 《European Journal of Forest Research》2018,137(4):517-525
Infections with Heterobasidion parviporum devalue the Norway spruce timber as the decayed wood does not meet the necessary quality requirements for sawing. To evaluate the incorporation of disease resistance in the Norway spruce breeding strategy, an inoculation experiment with H. parviporum on 2-year-old progenies of 466 open-pollinated families was conducted under greenhouse (nursery) conditions. Lesion length in the phloem (LL), fungal growth in sapwood (FG) and growth (D) were measured on an average of 10 seedlings for each family. The genetic variation and genetic correlations between both LL, FG and growth in the nursery trial and wood quality traits measured previously from 21-year old trees in two progeny trials, including solid-wood quality traits (wood density, and modulus of elasticity) and fiber properties traits (radial fiber width, tangential fiber width, fiber wall thickness, fiber coarseness, microfibril angle and fiber length). For both LL and FG, large coefficients of phenotypic variation (>?26%) and genetic variation (>?46%) were detected. Heritabilities of LL and FG were 0.33 and 0.42, respectively. We found no significant correlations between wood quality traits and growth in the field progeny trials with neither LL nor FG in the nursery trial. Our data suggest that the genetic gains may reach 41 and 52% from mass selection by LL and FG, respectively. Early selection for resistance to H. parviporum based on assessments of fungal spread in the sapwood in nursery material, FG, will not adversely affect growth and wood quality traits in late-age performance. 相似文献
53.
M. Gyuranecz K. Erdlyi L. Fodor K. Jnosi B. Szpe M. Füleki I. Szke B. Dnes L. Makrai 《Zoonoses and public health》2010,57(6):417-422
Thirteen Francisella tularensis strains were isolated from 22 seropositive brown hares (Lepus europaeus) originating from different parts of Hungary, and further two from a patas monkey (Erythrocebus patas) and vervet monkey (Chlorocebus aethiops). The isolates were identified as F. tularensis ssp. holarctica on the basis of culture, morphological and biochemical characteristics. The identification was verified by polymerase chain reaction and the sequencing of the partial 16S rRNA gene. Utilization of carbon sources of the 15 F. tularensis strains was characterized with the Biolog system. The system was able to identify the strains already after 4 h of incubation, not only after the standard 24 h. After the analysis and comparison of the metabolic profiles of our strains with the Biolog database, it was concluded that not all carbon sources indicated in the database were utilized by our isolates. The Biolog software fails to distinguish the highly virulent F. tularensis ssp. tularensis and the moderately virulent F. tularensis ssp. holarctica but the Biolog microplates can be manually read to differentiate the two subspecies based on glycerol source utilization. As all the studied strains were unable to use glycerol, they could be identified as F. tularensis ssp. holarctica. The dendrogram based on the metabolic relationship of the strains shows that the isolates are very similar to each other, which correlates with the conservative genetic character of F. tularensis ssp. holarctica. 相似文献
54.
为了明确新疆冬春麦区小麦春化和光周期基因的分布特点,利用STS标记对185份品种(系)的重要春化基因Vrn-A1、Vrn-B1、Vrn-D1、Vrn-B3和光周期基因Ppd-D1位点的等位变异组成进行了检测和分析。结果表明,在新疆小麦品种中,春化和光周期基因位点显性等位变异分布频率不同。含有春化显性等位变异Vrn-A1的品种47个,占供试品种(系)的25.4%;Vrn-B1为43个,占23.3%;Vrn-D1为38个,占20.5%;Vrn-B3位点不存在显性等位变异。春化显性等位变异Vrn-A1、Vrn-B1和Vrn-D1在冬、春性小麦内的分布比例也不同。在春性小麦品种(系)中,显性等位变异Vrn-A1出现的频率较高(55.3%);其次为Vrn-B1,占50.6%;Vrn-D1占44.7%。在冬性小麦中,仅有显性等位变异Vrn-B1出现,占2.0%。在光周期基因Ppd-D1位点,80.0%的品种(系)携带光不敏感显性等位变异Ppd-D1a;其中在春性和冬性小麦品种(系)中,Ppd-D1a出现的频率分别为83.5%和77.0%。新疆小麦品种(系)中,存在11种春化和光周期基因显性等位变异组合。 相似文献
55.
为了从蛋白质水平进一步揭示小麦抗旱机理,以旱地小麦品种晋麦47为试验材料,采用蛋白质双向电泳技术,结合质谱鉴定技术,研究幼苗在正常供水与水分胁迫(-0.5 MPa的PEG-6000溶液处理48h)后叶片蛋白质组表达谱间的差异,分析水分胁迫差异表达的蛋白种类及其功能.研究发现,在正常供水和水分胁迫处理两种条件下,幼苗叶片蛋白的双向电泳图谱均可重复检测到850个蛋白点;31个蛋白点在两种供水水平间表达量存在显著差异,其中17个蛋白点在水分胁迫处理下表达量明显增加,14个蛋白点表达量明显减少.对这些蛋白点进行肽指纹图谱分析,并利用Mascot软件在NCBInr数据库搜索,最终有26个蛋白点被成功鉴定;其中,未知功能蛋白7个;已知功能蛋白19个,主要涉及能量、代谢、抗病与防御、细胞结构、转录与翻译以及信号转导等功能类别.结果表明,小麦体内的多个代谢及调控途径参与了对干旱的应激反应.最后,本文还对鉴定到的差异蛋白点与水分胁迫的关系进行了分析和讨论. 相似文献
56.
Various antioxidant assays are used to characterize fruits consumed fresh or processed although an easy, reliable and cheap assay is not available to follow the changes in antioxidant power. This study tested the applicability of a recently developed antioxidant measuring system, Water-soluble (ACW) and Lipid-soluble (ACL) Antioxidant Capacity, using the PHOTOCHEM® instrument. Initially, 13 cultivars of 4 berry species were assayed with Photochem and compared with widely used methods based on single electron transfer reactions like ferric reducing ability of plasma, total polyphenolic content (TPC) and 2,2′-diphenyl-1-picrylhydrazyl radical-scavenging capacity. Assays based on hydrogen atom transfer reactions were also carried out including total radical-scavenger capacity (TRSC). The correlations among the results were all significant at P ≤ 0.05, except the one between TPC and ACW. The overall antioxidant capacity ranked on the order of strawberry < red currant < raspberry < black currant. However, significant differences could have been detected among genotypes and antioxidants assays used for the analysis. The Photochem instrument is not suitable for easy, cheap and high-throughput routine analysis of berry antioxidant capacity and hence is not preferable to other assays. 相似文献
57.
首先采用直接由材料本构关系形成单元M-N-Φ本构矩阵的方法推导出钢筋混凝土构件的单元刚度矩阵,编制了可以同时考虑材料和几何双重大量线性影响的有限元程序,与独立柱和框架柱的试验结果相比,计算结果吻合较好;然后,采用该分析程序对一榀二跨七层的规则框架算例进行分析,计算了各柱单元控制截面的二阶弯矩,并分析了二阶弯矩随各影响因素的变化规律;最后,以现行设计规范中标准柱偏心距增大系数的原型公式在本研究程序条件下修正公式为基点,分析了所选算例各柱单元的计算长度随各影响因素的变化规律。 相似文献
58.
59.
60.
【目的】研究裹包全混合日粮(Total mixed ration,TMR)中添加不同水平的双乙酸钠(SDA)对贮存效果的影响。【方法】在裹包TMR中分别添加鲜重质量分数0,0.1%,0.3%和0.5%的SDA,于贮存后第0,3,7,15和30天,对裹包TMR的感官、营养成分、发酵指标和有氧稳定性进行分析。【结果】0.3%和0.5%SDA添加组的裹包TMR可以良好贮存30 d。SDA添加水平越高,裹包TMR的有氧稳定性越好。添加SDA对裹包TMR的感官和营养成分影响差异较小。与其他2个处理相比,0.3%和0.5%SDA添加水平可以显著降低裹包TMR的pH值(P<0.05)和NH3-N/TN值(P<0.05)。【结论】从经济效益和添加效果考虑,在裹包TMR中添加0.3%SDA为适宜水平。 相似文献