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The role of genomic structural variation in the genetic improvement of polyploid crops 预览
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作者 Sarah-Veronica Schiessl Elvis Katche +2 位作者 Elizabeth Ihien Harmeet Singh Chawla Annaliese S. Mason 《作物学报:英文版》 CAS CSCD 2019年第2期127-140,共14页
Many of our major crop species are polyploids,containing more than one genome or set of chromosomes.Polyploid crops present unique challenges,including difficulties in genome assembly,in discriminating between multipl... Many of our major crop species are polyploids,containing more than one genome or set of chromosomes.Polyploid crops present unique challenges,including difficulties in genome assembly,in discriminating between multiple gene and sequence copies,and in genetic mapping,hindering use of genomic data for genetics and breeding.Polyploid genomes may also bemore prone to containing structural variation,such as loss of gene copies or sequences (presence–absence variation) and the presence of genes or sequences inmultiple copies (copynumber variation).Although the two main types of genomic structural variation commonly identified are presence–absence variation and copy-number variation,we propose that homeologous exchanges constitute a third major form of genomic structural variation in polyploids.Homeologous exchanges involve the replacement of one genomic segment by a similar copy from another genome or ancestrally duplicated region,and are known to be extremely common in polyploids.Detecting all kinds of genomic structural variation is challenging,but recent advances such as optical mapping and long-read sequencing offer potential strategies to help identify structural variants even in complex polyploid genomes.All three major types of genomic structural variation (presence–absence,copy-number,and homeologous exchange) are now known to influence phenotypes in crop plants,with examples of flowering time,frost tolerance,and adaptive and agronomic traits.In this review,we summarize the challenges of genome analysis in polyploid crops,describe the various types of genomic structural variation and the genomics technologies and data that can be used to detect them,and collate information produced to date related to the impact of genomic structural variation on crop phenotypes.We highlight the importance of genomic structural variation for the future genetic improvement of polyploid crops. 展开更多
关键词 Presence–absence VARIATION COPY-NUMBER VARIATION Homeologous exchanges Genome structure PAN-GENOME
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Spatial and seasonal distribution of intertidal macrobenthos with their biomass and functional feeding guilds in the Naf River estuary,Bangladesh 预览
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作者 Md. Abu NOMAN MAMUNUR Rashid +1 位作者 M SHAHANUL Islam M. Belal HOSSAIN 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第3期1010-1023,共14页
The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic animals.However,detailed information on macrobenthic communities... The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic animals.However,detailed information on macrobenthic communities is rarely available in this area.Our study focused on the seasonal and spatial variability of macrobenthic community structure with their biomass and functional guilds.In total,fortyseven taxa were identified under nine major groups and seven functional feeding guilds.Among macrobenthic taxa,Polychaeta was dominant in both seasons and all over the estuary contributing 60%of total benthos.The mean abundance of macrobenthos was higher during the pre-monsoon(2 972±1 994 inds./m^2)than the monsoon(1 572±361 inds./m^2)being maximum at mid-estuary region and minimum at upper and lower estuary regions.Of the diversity indices,density(P=0.01,P=0.003),the number of taxa(P=0.000 3,P=0.000 9)and Margalef′s Index(P=0.000 4,P=0.001)of macrobenthos were significantly different among stations and seasons.Shannon-Weiner index(P=0.009,P=0.12)and Pielou’s evenness index(P=0.03,P=0.14)had significant differences among stations but not among seasons.Cluster analysis suggested that distribution of macrofauna is strongly influenced by seasonality.Among the feeding types,carnivorous were found to be dominant at the upper and mid-estuarine regions,and herbivorous were at lower estuarine regions.Carnivorous species were dominant in both seasons.Omnivores have shown to be the most abundant feeding type in terms of biomass though herbivores were highest during monsoon. 展开更多
关键词 MACROBENTHOS seasonal VARIATION SPATIAL VARIATION feeding GUILDS BIOMASS NAF River estuary
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流域尺度下地形属性对土壤质地类型变异的影响——以重庆市彭水县一小流域为例 预览
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作者 马冉 刘洪斌 武伟 《农业资源与环境学报》 CAS 北大核心 2019年第3期279-286,共8页
为探究流域尺度下地形属性对土壤质地类型变异的影响,以西南地区重庆市彭水县的一个流域为研究区,基于成土母质和地形因子,运用分类回归树(Classification and regression tree,CART)模型,对研究区1165个样点数据进行分析。结果表明:成... 为探究流域尺度下地形属性对土壤质地类型变异的影响,以西南地区重庆市彭水县的一个流域为研究区,基于成土母质和地形因子,运用分类回归树(Classification and regression tree,CART)模型,对研究区1165个样点数据进行分析。结果表明:成土母质和地形因子均对土壤质地类型有重要影响,相对重要性较高的因子排序:成土母质(PAR)>风效应(WindEff)>地形湿度指数(SAGATWI);不同母质、不同质地之间地形因子存在显著差异,风效应(WindEff)和漫射辐射(DiffuseIns)分别是奥陶系和志留系母质条件下影响土壤质地分类的相对重要性最高的地形因子;流域尺度CART模型解释率为86.3%,说明CART模型对土壤质地分类精度高。研究表明,基于成土母质和地形因子构建的模型解释效果好,影响显著,可为该地区土壤利用区划和管理提供科学依据。 展开更多
关键词 流域尺度 CART模型 母质 地形因子 土壤质地类型 变异
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红锥优树二代家系抗逆性苗期选择研究 预览
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作者 申文辉 谭长强 +4 位作者 劳庆祥 郝海坤 曹艳云 郑威 黄志玲 《西南林业大学学报》 CAS 北大核心 2019年第2期11-17,共7页
通过对29个红锥优树二代家系苗高、地径及抗性生理指标进行测定,运用隶属函数法对抗逆性优良家系进行筛选和评价。结果表明:各指标29个家系间均存在较大差异。苗高为36.5~74.8 cm,地径为5.03~8.58 mm,可溶性糖含量为3.37%~5.84%,淀粉含... 通过对29个红锥优树二代家系苗高、地径及抗性生理指标进行测定,运用隶属函数法对抗逆性优良家系进行筛选和评价。结果表明:各指标29个家系间均存在较大差异。苗高为36.5~74.8 cm,地径为5.03~8.58 mm,可溶性糖含量为3.37%~5.84%,淀粉含量为2.01%~4.09%,可溶性蛋白含量为20.4~38.1 mg/g,脯氨酸含量为2.66~5.04μg/g,丙二醛含量为15.6~87.5 nmol/g,过氧化物酶含量为12.3~88.0μ/(g·min),超氧化物歧化酶含量为53.2~82.9 U/g。各抗逆性指标各红锥家系间均存在显著差异。采用多指标的综合评价方法筛选出10个家系为抗逆性优良家系,同时结合苗高及地径生长指标,进一步筛选出P3、B2、A7、B5家系的速生抗逆性最强。 展开更多
关键词 红锥 家系 苗期 变异 选择 抗性生理
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Identifying Intraspecific Variation in Venom Yield of Chinese Cobra(Naja atra) from Ten Populations in Mainland China
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作者 Jianfang GAO Yin YIN +4 位作者 Yanfu QU Jin WANG Longhui LIN Hongliang LU Xiang JI 《亚洲两栖爬行动物研究:英文版》 SCIE CSCD 2019年第1期32-40,共9页
Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venom... Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venomous snake commonly found in southeastern China, where it causes a heavy burden of snakebites. To examine the effects of various factors(morphology, sex, age, season, and geographical origin) on the venom yield in this snake, we collected venom samples of 446 individuals(426 adults and 20 neonates) from 10 populations of N. atra over an eightyear period. We used two variables, lyophilized venom mass(venom yield) and solid content of venom(% solids), to quantify the venom yield. We used linear regression analysis to check if venom yield was related to morphological factors, one-way ANOVA and one-way ANCOVA to detect the sexual, ontogenetic, and geographic variation in venom yield, and repeated-measures ANOVA to examine seasonal shifts in venom yield. Our results indicate that venom yield of N. atra is positively related to the morphological traits examined, with male snakes expelling more venom than females. Venom yield in N. atra was age-related, with elder snakes always expelling more venom than younger ones. Geographic variation in venom yield was also observed, while seasonal variation was not. The solid content of venom was lower in males than in females, but this was not related to morphology, season, age, or geography. Our findings suggest that venom yield in N. atra is influenced by multiple factors, as well as by the interactions among these factors. 展开更多
关键词 Naja atra VENOM YIELD INTRASPECIFIC variation SNAKEBITE
Molecular test shows the color pattern is not so reliable in diagnostic of genus Dysphaea Selys(Odonata:Euphaeidae)
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作者 Yao Ji Xin Yu 《动物分类学报:英文版》 CSCD 2019年第2期91-99,共9页
A molecular study based on COI, 16S and 28S genes reveals that a batch of specimens(7 males and 4 females) of Dysphaea Selys, 1853 collected from central Vietnam,which include different color patterns of wings and bod... A molecular study based on COI, 16S and 28S genes reveals that a batch of specimens(7 males and 4 females) of Dysphaea Selys, 1853 collected from central Vietnam,which include different color patterns of wings and body, and were originally identified as three different species, are all the same species. This study implies that, in some group of Odonata,identification only depending on color pattern may be unreliable, no matter what huge variations there are. 展开更多
关键词 ODONATA DRAGONFLY wing color pattern variation MOLECULAR PHYLOGENY
2012-2017年山东省菏泽市流行性感冒疫情特点与病毒类型监测结果
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作者 马永旭 戴洪柱 +2 位作者 李晓寒 马敬仓 徐凌忠 《医学动物防制》 2019年第2期125-129,133共6页
目的了解2012-2017年菏泽市流行性感冒(简称流感)疫情特点与病毒类型,指导菏泽市流感防控工作。方法利用'中国疾病预防控制信息系统'选取2012-2017年菏泽市流行性感冒监测病例,对流行性感冒疫情的三间分布特征及流行性感冒病毒... 目的了解2012-2017年菏泽市流行性感冒(简称流感)疫情特点与病毒类型,指导菏泽市流感防控工作。方法利用'中国疾病预防控制信息系统'选取2012-2017年菏泽市流行性感冒监测病例,对流行性感冒疫情的三间分布特征及流行性感冒病毒病原学特点进行描述性分析。流行性感冒病毒的分离和鉴定采用细胞培养方法。结果 2012-2017年菏泽市共报告流感病例4 014例,年均发病率7. 94/10万;采集1 334例流感样病例咽拭子标本,检出流感病毒329株,阳性率为24. 66%。共监测到H3N2亚型、BY型、BV型和新甲H1N1型4个病毒类型。结论 2012-2017年菏泽市流感疫情相对稳定,流感流行主要集中在冬春季,县区分布、年龄分布、月份分布均不平衡,每年的优势流行株均不相同,先后以H3N2型、BY型、H3N2型、BV型为优势株。为预防流感疫情的发生,今后要加强流感疫苗接种,是预防流感最有效的方式。要扩大流感监测范围,不断提高流感防控水平。 展开更多
关键词 流行性感冒 病毒 变异 流感样病例 监测
一例先天性鱼鳞病患儿的临床表现及TGM1基因变异分析
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作者 胡清华 易丽君 +4 位作者 陈卡 周菁 陈丽萍 曾丽春 李红 《中华医学遗传学杂志》 CAS CSCD 2019年第4期357-359,共3页
目的探讨1例先天性鱼鳞病患儿的遗传学病因。方法通过对1例疑似的先天性鱼鳞病患儿进行Panel测序,用Sanger测序对筛查出的可疑致病变异进行验证。结果先证者TGM1基因存在c.327delG(p.Met109Ilefs*2)和c.791G>A(p.Arg264Gln)复合杂合... 目的探讨1例先天性鱼鳞病患儿的遗传学病因。方法通过对1例疑似的先天性鱼鳞病患儿进行Panel测序,用Sanger测序对筛查出的可疑致病变异进行验证。结果先证者TGM1基因存在c.327delG(p.Met109Ilefs*2)和c.791G>A(p.Arg264Gln)复合杂合变异,其父亲携带c.791G>A杂合变异,母亲携带c.327delG杂合变异。在101名正常对照中未检测到上述变异。c.327delG变异为未报道过的新变异。上述变异均可能导致TGase-1蛋白质功能受损,可能为致病性变异。结论TGM1基因c.327delG及c.791G>A复合杂合变异可能为先证者的致病原因。 展开更多
关键词 先天鱼鳞病 TGM1基因 基因变异
长江荆江三口环境流变化研究 预览
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作者 王鸿翔 李萌萌 +1 位作者 马志军 郭文献 《水力发电》 北大核心 2019年第5期1-6,共6页
为了综合评价长江荆江三口的环境流指标在人类活动干扰前后的变化特征,选取了荆江三口主要水文站1955年~2016年逐日流量资料,运用Mann-Kendall法、累积距平法检验以及滑动T检验法检验时间径流序列的突变性,将时间径流序列划分为累积效... 为了综合评价长江荆江三口的环境流指标在人类活动干扰前后的变化特征,选取了荆江三口主要水文站1955年~2016年逐日流量资料,运用Mann-Kendall法、累积距平法检验以及滑动T检验法检验时间径流序列的突变性,将时间径流序列划分为累积效应不显著阶段与累积效应显著阶段,并以IHA软件为平台计算分析了荆江三口在人类活动影响前后环境流的变化情况。结果表明,长江荆江三口3个水文站的环境流组成在人类干扰前后呈不同程度的变化;环境流组成呈单一化趋势,枯水流量事件、大洪水事件和小洪水事件变化较大,15个环境流指标影响较大。 展开更多
关键词 环境流指标 变化 分析 洞庭湖 荆江三口
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窑洞建筑景观基因的识别及其变异
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作者 祁剑青 邓运员 +1 位作者 郑文武 刘沛林 《干旱区资源与环境》 CSSCI CSCD 北大核心 2019年第6期84-89,共6页
以黄土高原为研究区域,运用聚落景观基因理论与方法,对窑洞建筑的景观基因进行识别并对基因的变异进行分析。遵循内在唯一性原则、外在唯一性原则、局部唯一性原则以及总体优势性原则,将窑洞的景观基因要素分解为立面形态基因、平面布... 以黄土高原为研究区域,运用聚落景观基因理论与方法,对窑洞建筑的景观基因进行识别并对基因的变异进行分析。遵循内在唯一性原则、外在唯一性原则、局部唯一性原则以及总体优势性原则,将窑洞的景观基因要素分解为立面形态基因、平面布局基因、建筑材料基因、局部装饰基因等四个方面。拱形窑脸是窑洞区别于其他民居建筑的主要标志性特征,因而主体基因为立面形态基因,其余皆为附属基因。在'向心+围合'的中国传统聚落景观形态的大背景下,窑洞的平面布局基因随地形条件的不同产生了变异。为适应不同区域的黄土土质与气候环境,立面形态基因发生了变异。随着建筑技术的进步,窑洞由靠崖窑衍生出了地坑窑、锢窑等形态,建筑材料由原先的生土扩大为土坯、砖、石,在一定程度上对窑洞形态的变异产生影响。 展开更多
关键词 黄土高原 窑洞 景观基因 识别 变异
基于区域增长和统一化水平集CT分割重建在肝动脉变异中的应用 预览
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作者 陈良 张学昌 +2 位作者 朱杰 郑四鸣 刘艳芳 《浙江医学》 CAS 2019年第6期542-546,共5页
目的探讨基于区域增长和统一化水平集的半自动肝脏及其管道CT分割重建方法的可行性,评价该三维重建技术在诊断肝动脉变异中的准确性。方法选取拟行肝切除术的患者300例,术前均接受腹部增强CT检查,应用区域增长和统一化水平集的半自动肝... 目的探讨基于区域增长和统一化水平集的半自动肝脏及其管道CT分割重建方法的可行性,评价该三维重建技术在诊断肝动脉变异中的准确性。方法选取拟行肝切除术的患者300例,术前均接受腹部增强CT检查,应用区域增长和统一化水平集的半自动肝脏及其管道分割重建方法构建3D肝动脉重建模型,并根据Michels分型标准进行分型。所有患者均接受手术治疗,记录术中肝动脉变异情况以及手术、病理和术后资料,并比较模型的可靠性。结果所有患者均顺利完成手术,且无术中及术后死亡病例。在所有患者中,最常见的肝动脉分型为Ⅰ型(76.6%),Ⅲ型(7.3%)、Ⅴ型(4%)、Ⅵ型(4%)、Ⅱ型(2.6%)、Ⅸ型(2.6%)、Ⅳ型(0.6%),无Ⅶ型、Ⅷ型、Ⅹ型肝动脉分型患者,其他类型占比为2%。通过与术中实际情况进行对照发现,区域增长和统一化水平集的半自动肝脏及其管道分割重建方法构建的3D肝动脉重建模型准确率为100%。结论通过螺旋CT检查并应用区域增长和统一化水平集的半自动肝脏及其管道分割重建方法构建3D肝动脉重建模型,能对肝动脉进行准确分型,而了解异常的肝动脉分型无论对于外科手术和介入性肝脏手术都起到了重要的作用。 展开更多
关键词 区域增长 水平集 肝动脉 三维重建 变异 肝切除
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右下肺静脉及其属支分布与汇合模式分型的多层螺旋CT影像解剖学研究
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作者 王晓妮 王晨辰 +2 位作者 李祥彤 张正峰 刘林祥 《中华解剖与临床杂志》 2019年第2期138-144,共7页
目的探讨右下肺静脉(RLL)属支的多层螺旋CT血管造影(MSCTA)影像解剖学分布特征、汇合模式分型及其临床应用价值。方法采用回顾性横断面研究方法。自2017年3月—2018年7月泰山医学院附属医院行MSCTA检查的病例中,筛选肺静脉及属支显示优... 目的探讨右下肺静脉(RLL)属支的多层螺旋CT血管造影(MSCTA)影像解剖学分布特征、汇合模式分型及其临床应用价值。方法采用回顾性横断面研究方法。自2017年3月—2018年7月泰山医学院附属医院行MSCTA检查的病例中,筛选肺静脉及属支显示优良者100例,其中男54例、女46例,年龄24~86(58.9±13.54)岁。将MSCTA原始图像传到后处理工作站,进行容积再现(VR)和多平面重组(MPR),观察右下肺静脉属支数目、分布特征及汇合方式,进而对其进行命名和分型。结果右下肺静脉整体汇合方式分型有RLLⅠ型(2支型)、RLLⅡ型(3支型)、RLLⅢ型(4支型),分别占67%(67/100)、28%(28/100)、5%(5/100)。RLLⅠ型最常见,有2种汇合方式、5种分型;RLLⅡ型最复杂,有6种汇合方式、7种分型;RLLⅢ型最少见,有4种汇合方式、4种分型。少见的静脉引流模式中,异位中叶静脉(异位V4、异位V4+V5)和异位上叶静脉(异位V2)分别占7%(7/100)和4%(4/100)。上段静脉分为单干型和双干型,分别占88%(88/100)、12%(12/100)。内侧底段静脉(V7)为最细小的底段静脉,其汇入处无规律,共统计了10种汇入情况。前段静脉(V8)、外侧底段静脉(V9)、后底段静脉(V110)有二分支型、三分支型和四分支型3种型式,分别占95%(95/100)、4%(4/100)和1%(1/100)。结论右下肺静脉属支引流及汇合模式复杂多变;手术前MSCTA可清晰显示肺静脉属支的分布规律,从而提高胸腔镜下解剖性肺段切除术的安全性。 展开更多
关键词 肺静脉 分型 变异 体层摄影术 X线计算机 血管造影 电视胸腔镜手术
Further analyses of variation of ribosome DNA copy number and polymorphism in ciliates provide insights relevant to studies of both molecular ecology and phylogeny
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作者 Yurui Wang Chundi Wang +3 位作者 Yaohan Jiang Laura A.Katz Feng Gao Ying Yan 《中国科学:生命科学英文版》 SCIE CAS CSCD 2019年第2期203-214,共12页
Sequence-based approaches, such as analyses of ribosome DNA(rDNA) clone libraries and high-throughput amplicon sequencing, have been used extensively to infer evolutionary relationships and elucidate the biodiversity ... Sequence-based approaches, such as analyses of ribosome DNA(rDNA) clone libraries and high-throughput amplicon sequencing, have been used extensively to infer evolutionary relationships and elucidate the biodiversity in microbial communities.However, recent studies demonstrate both r DNA copy number variation and intra-individual(intra-genomic) sequence variation in many organisms, which challenges the application of the rDNA-based surveys. In ciliates, an ecologically important clade of microbial eukaryotes, rDNA copy number and sequence variation are rarely studied. In the present study, we estimate the intraindividual small subunit rDNA(SSU r DNA) copy number and sequence variation in a wide range of taxa covering nine classes and 18 orders of the phylum Ciliophora. Our studies reveal that:(i) intra-individual sequence variation of SSU rDNA is ubiquitous in all groups of ciliates detected and the polymorphic level varies among taxa;(ii) there is a most common version of SSU rDNA sequence in each cell that is highly predominant and may represent the germline micronuclear template;(iii)compared with the most common version, other variant sequences differ in only 1–3 nucleotides, likely generated during macronuclear(somatic) amplification;(iv) the intra-cell sequence variation is unlikely to impact phylogenetic analyses;(v) the rDNA copy number in ciliates is highly variable, ranging from 103 to 106, with the highest record in Stentor roeselii. Overall,these analyses indicate the need for careful consideration of SSU r DNAvariation in analyses of the role of ciliates in ecosystems. 展开更多
关键词 CILIATES SSU RDNA sequence VARIATION phylogenetic ANALYSES RDNA copy number ecological significance
Selection of female parents with high fertility and high combining abilities for cross-breeding Populus tomentosa 预览
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作者 Feng-ying Bai Ning Kang +1 位作者 Ping-dong Zhang Xiang-yang Kang 《林业研究:英文版》 CAS CSCD 2019年第2期445-450,共6页
To select maternal parents with high fertility and high combining ability during cross breeding of Populus tomentosa Carr.,the ploidy level of 75 female clones was determined using flow cytometry.In addition,genetic v... To select maternal parents with high fertility and high combining ability during cross breeding of Populus tomentosa Carr.,the ploidy level of 75 female clones was determined using flow cytometry.In addition,genetic variations and phenotypic correlations of seed traits and early growth traits,as well as the general combining ability(GCA)for seedling height(SH)and basal diameter(BD)of all diploid half-sib families were examined.A total of 26 natural triploid clones were identified.For all diploid families,family effects were significant for inflorescence length(IL),thousand kernel weight(TKW),seedling emergence rate(SER),and for SH and BD.There was a positive correlation between TKW and other traits,excluding IL.The seed-bearing coefficient(NS 9 SER)ranged from zero to 32.4%.Clones 3-10-2,2-8,3119,3206,and 3-10-1 had the best performance of the GCA for SH and BD.Based on the fertility and GCA for SH and BD,clone 3-10-2 and clone 3119 could be used as female parents for controlled cross-breeding of P.tomentosa. 展开更多
关键词 FERTILITY ABILITY General COMBINING ABILITY GENETIC VARIATION Half-sib family POPULUS tomentosa
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Variation in allelic frequencies at loci associated with kernel weight and their effects on kernel weight-related traits in winter wheat 预览
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作者 Teng Li Hongwei Liu +8 位作者 Chunyan Mai Guangjun Yu Huili Li Lingzhi Meng Dawei Jian Li Yang Yang Zhou Hongjun Zhang Hongjie Li 《作物学报:英文版》 CAS CSCD 2019年第1期30-37,共8页
Knowledge of allelic frequencies at loci associated with kernel weight and effects on kernel weight-related traits is crucial for yield improvement in wheat.Kernel weight-related traits were evaluated in 200 Chinese w... Knowledge of allelic frequencies at loci associated with kernel weight and effects on kernel weight-related traits is crucial for yield improvement in wheat.Kernel weight-related traits were evaluated in 200 Chinese winter wheat cultivars(lines)grown at the Xinxiang Experimental Station,Chinese Academy of Agricultural Sciences,Xinxiang in Henan Province,for three consecutive years from 2014 to 2016.Alleles associated with kernel weight at nine loci,TaCKX6-D1,TaCwi-A1,TaCWI-4A,TaGS1a,TaGS5-A1,TaGS3-3A,TaGW2-6A,TaSus2-2B,and TaTGW6-A1,were determined for all cultivars(lines).ANOVA showed that genotypes,years and their interactions had significant effects on thousand-kernel weight(TKW),kernel length(KL)and kernel width(KW).The overall mean frequencies of alleles conferring high and low TKW at the nine loci were 65.9%and 33.4%,with the ranges of 37.0%–85.0%and 13.5%–63.0%for single loci.The frequencies of high-TKW alleles were over 50.0%at eight of the loci.Genotypes at each locus with the high-TKW allele had higher TKW than those with the low-TKW allele.The high-TKW allele Hap-H at the TaSus2-2B locus can be preferably used to increase grain yield due to its high TKW(49.32 g).A total of 18 main allelic combinations(ACs)at nine loci were detected.Three ACs(AC1–AC3)had significantly higher TKW than AC6 with high-TKW alleles at all nine loci even though they contained some low-TKW alleles.This indicated that other loci controlling kernel weight were present in the high-TKW cultivars.This work provides important information for parental selection and marker-assisted selection for breeding. 展开更多
关键词 Allelic frequency Allelic VARIATION Functional MARKERS TRITICUM AESTIVUM
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Dimensional Variation Modeling of Aircraft Compliant Part Assembly Considering Clamping Force Change 预览
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作者 TAN Changbai ZHANG Wei WANG Zhiguo 《南京航空航天大学学报:英文版》 EI CSCD 2019年第2期298-305,共8页
Compliant parts are widely applied to aircraft structures.Due to the ease of deformation of compliant parts in assembly,the prediction of assembly variation is especially important for assembly quality control.A dimen... Compliant parts are widely applied to aircraft structures.Due to the ease of deformation of compliant parts in assembly,the prediction of assembly variation is especially important for assembly quality control.A dimensional variation model considering the clamping force change in assembly is proposed based on the method of influence coefficient(MIC).First,the assembly process is decomposed into several steps including positioning,clamping,joining,and spring-back.Then,the force-displacement relationship is formulated according to the varied force conditions on the parts in each assembly step.Finally,two examples are illustrated to validate the proposed assembly variation model.The results show the impact of clamping force change is significant on the assembly variation,and the proposed model can predict the assembly variation more accurately than the referred method without clamping force correction at the over-constrained locating points of fixture. 展开更多
关键词 AIRCRAFT dimensional variation compliant parts CLAMPING force CHANGE method of influence coefficient(MIC)
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基于DI指数的佛山市气象干旱变化趋势分析 预览
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作者 麦雪湖 梁华玲 +1 位作者 麦文强 程银琳 《中低纬山地气象》 2019年第3期75-77,共3页
该文根据逐日气象干旱指数DI指数统计佛山1959—2017年气象干旱日数,采用“二项式系数加权平均法”进行趋势分析,结合M-K检验和小波分析等方法分析气候突变和周期变化,对佛山市59a的气象干旱日数变化趋势进行分析研究。结果表明:近59a... 该文根据逐日气象干旱指数DI指数统计佛山1959—2017年气象干旱日数,采用“二项式系数加权平均法”进行趋势分析,结合M-K检验和小波分析等方法分析气候突变和周期变化,对佛山市59a的气象干旱日数变化趋势进行分析研究。结果表明:近59a佛山年气象干旱日数总体呈减少的趋势,2015年以后年气象干旱日数呈显著减少的趋势,2010—2011年是气象干旱日数突变减少的开始时段;年气象干旱日数存在着3a、7a及20a的周期时间尺度,准3a的短周期存在于1980年前,准7a的周期出现在1980年后,20a的周期有着最强的振荡,是年气象干旱日数变化的首要主周期。 展开更多
关键词 气象干旱 变化趋势 佛山
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Using proximal sensor data for soil salinity management and mapping 预览
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作者 GUO Yan ZHOU Yin +5 位作者 ZHOU Lian-qing LIU Ting WANG Lai-gang CHENG Yong-zheng HE Jia ZHENG Guo-qing 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第2期340-349,共10页
Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China’s coastline. However, information about the spa... Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China’s coastline. However, information about the spatio–temporal variation of soil salinity in these reclaimed regions is limited. As such, obtaining this information is crucial for mapping the variation in saline areas and to identify suitable salinity management strategies. In this study, we employed EM38 data to conduct digital soil mapping of spatio–temporal variation and map these variations of different site-specific zones. The results indicated that the distribution of soil salinity was heterogeneous in the middle of, and that the leaching of salts was significant at the edges of, the study field. Afterwards, fuzzy-k means algorithm was used to divide the site-specific management zones within the time series apparent soil electrical conductivity(ECa) data and the spatial correlations of variation. We concluded that two management zones are optimal to guide precision management. Zone A had an average salinity level of about 165 mS m–1, in which salt-tolerant crops, such as cotton and barley can grow normally, while crops such as soybean and cowpeas may be planted using leaching and increasing the mulching film methods to reduce the accumulation of salt in surface soil. In Zone B, there was a low salinity level with a mean of 89 mS m–1 for ECa, which allows for rice, wheat, and a wide range of vegetables to be grown normally. In such situations, measures such as an optimized combination of irrigation and drainage, as well as soil amendment can be taken to adjust and control the salt content. Particularly, flattening the land with a large-scale machine was used to improve the ability of micro-topography to influence salt migration;rice and other dry, land crops were planted in rotation in combination with utilizing salt-leaching multiple times to speed up desalinization. 展开更多
关键词 apparent SOIL electrical conductivity(ECa) SOIL SALINITY EM38 spatial variation MANAGEMENT zone
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Characteristics of volatile organic compounds,NO2, and effects on ozone formation at a site with high ozone level in Chengdu
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作者 Yuanyuan Deng Jing Li +2 位作者 Yaqi Li Rongrong Wu Shaodong Xie 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第1期334-345,共12页
Chengdu is a megacity in the southwest of China with high ozone (O3) mixing ratio. Observation of volatile organic compounds (VOCs),NO2 and O3 with high temporal resolution was conducted in Chengdu to investigate the ... Chengdu is a megacity in the southwest of China with high ozone (O3) mixing ratio. Observation of volatile organic compounds (VOCs),NO2 and O3 with high temporal resolution was conducted in Chengdu to investigate the chemical processes and causes of high O3 levels.The hourly mixing ratios of VOCs,NO2,and Os were monitored by an online system from 28 August to 7 October,2016.According to meteorological conditions, Chengdu,with relative warm weather and low wind speed,is favorable to O3 formation. Part of the O3 in Chengdu may be transported from the downtown area.In O3 episodes, the average mixing ratios of NO2 and O3 were 20.20 ppbv and 47.95ppbv,respectively.In non-O3 episodes,the average mixing ratios of NO2 and O3 were 16.38 ppbv and 35.15 ppbv, respectively.The average mixing ratio of total VOCs (TVOCs)was 40.29ppbv in non-O3 episodes,which was lower than that in O3 episodes (53.19ppbv).Alkenes comprised 51.7% of the total O3formation potential (OFP)in Chengdu,followed by aromatics which accounted for 24.2%.Ethylene,trans-pentene,propene,and BTEX (benzene,ethylbenzene, toluene,rn/p-xylene,o-xylene)were also major contributors to the OFP in Chengdu.In O3 episodes,intensive secondary formations were observed during the campaign.Oxygenated VOCs (OVOCs),such as acetone,Methylethylketone (MEK),and Methylvinylketone (MVK) were abundant.Isoprene rapidly converted to MVK and Methacrolein (MACR)during O3 episodes.Acetone was mainly the oxidant of C3-C5 hydrocarbons. 展开更多
关键词 OZONE FORMATION VOCs NO2 OFP DIURNAL VARIATION
2014-2017年中国部分地区PEDV流行株S基因遗传进化分析
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作者 郑慧华 张鸿鑫 +3 位作者 韩昊莹 乔涵 赵宇 陈红英 《安徽农业大学学报》 CAS CSCD 2019年第2期249-255,共7页
参考GenBank中PEDV经典CV777毒株基因组序列设计特异性引物,采用RT-PCR方法对临床采集的疑似PEDV样品进行S基因扩增、克隆和测序,拼接获得30条完整S基因序列,并进行遗传进化及同源性分析。结果显示,获得的30条PEDV S基因与25个参考株S... 参考GenBank中PEDV经典CV777毒株基因组序列设计特异性引物,采用RT-PCR方法对临床采集的疑似PEDV样品进行S基因扩增、克隆和测序,拼接获得30条完整S基因序列,并进行遗传进化及同源性分析。结果显示,获得的30条PEDV S基因与25个参考株S基因的核苷酸相似性介于93.6%~99.8%;且各流行毒株与经典毒株比较,具有多处的点突变、插入和缺失。与其他参考株相比,S1区存在157个氨基酸突变位点,占总数的65.7%(157/239),暗示PEDV的S1区域比S2区域易发生变异;表明目前中国PEDV流行株已经发生了变异,在一定程度揭示了免疫猪群仍然发病的原因。 展开更多
关键词 PEDV S基因 遗传进化分析 变异
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