986 resultados para 2 Samuel 7
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青杨组(Section Tacamahaca Spach)杨树是我国重要的乡土经济树种,目前对其分子遗传变异和系统进化的研究还很少,尤其是在青杨组杨树遗传资源极为丰富的川西地区,杨树的分子进化及亲缘关系的研究极为缺乏,非常不利于该树种遗传资源的开发和利用。本研究从川西地区收集了青杨(Populus cathayana)、青海杨(P. prezewalskii)、滇杨(P. yunnanensis)、康定杨(P. kangdingensis)、西南杨(P. schneideri)、小叶杨(P.simonii)和三脉青杨(P. trinervis)这7 个青杨组树种的10 个群体,利用多种分子标记手段对其种间的亲缘关系进行比较,并结合形态和地史资料进行了全面的研究和评价,得到了如下的主要研究结果: 1. SSR 和ISSR 位点变异丰富。通过10 对引物对50 个杨树个体的DNA 样品进行了SSR 分析,所有位点展现了丰富的群体间和种间的多态性,多态位点率达到了100%,每位点的等位基因数变化范围为5 ~ 17,平均为11.9 个;通过11 条ISSR 随机引物对供试的混合DNA 样品进行分析,共检测到130 个标记,其中多态性标记为119 个,多态百分率为91.5%。研究认为,SSR 单个标记能展现高水平信息,而ISSR 单个引物能探测更多数量多态性。通过两个标记的遗传距离、聚类图和PCA 分析,表明:同一种内不同群体间的同源性最高;康定杨和西南杨有较近的亲缘关系;小叶杨和三脉青杨聚合在一起,显示了其相互较近的亲缘关系;滇杨与其它杨树种可能存在着较远的亲缘关系。 2. 采用4 对选择性引物对7 个青杨组杨树种10 个群体进行AFLP 分析,总共扩增出284 个位点,其中200 个位点显示出了多态性,多态位点百分比为70.4%,平均多态带为50 条。TE-AFLP 的分析总共扩增出192 个位点,其中139 个位点显示出了多态性,多态位点百分比为72.4%,平均多态带为34.7 条。比较的结果表明AFLP、TE-AFLP 的遗传信息含量比较接近,略小于ISSR,大约仅为SSR 的1/3;但这两个基于AFLP 的标记系统的信息探察能力也远大于ISSR 和SSR 标记系统。这两个分子标记的聚类结果,显示小叶杨、三脉青杨和滇杨三个种聚为一组,其中小叶杨与三脉青杨的亲缘关系更近;其它几个杨树种聚为一类,西南杨与青杨表现出较近的亲缘关系。 3. 所有7 对cpSSR 引物中,仅有4 个叶绿体位点在种间具有多态性,而在种内群体中并不具有多态性,共检测出13 个条带,组合成了4 种不同的单倍型;对于cpDNA的5 对引物,共检测出了73 条酶切片段,其中52 条是多态带,组合成了9 种不同的单倍型;而5 对mtDNA 通用引物未能检测出多态性的条带,表现出线粒体的保守性。叶绿体的聚类分析认为,小叶杨、三脉青杨和滇杨有较近的母性起源,且依次聚合;其余四种杨树聚为一类,并且康定杨与西南杨表现出最近的亲缘关系,并依次与青杨和青海杨聚合。 4. 根据本文的分子数据,结合形态和生境分布资料分析认为:青杨组杨树种内群体间的遗传变异程度是小于种间的遗传差异,显示了与传统分类一致的结果;三脉青杨和小叶杨有很近的亲缘关系,可能拥有相同的祖先类群;滇杨与小叶杨和三脉青杨之间具有一定的亲缘关系,特别是在其母性祖先的起源上有着一定的同源性;西南杨与青杨和康定杨均保持着较近的亲缘关系,且有可能是这两个种原始祖先杂交后所形成的。 Although western Sichuan is regarded as a natural distribution and variation center forthe Section Tacahamaca of the Populus species in China, little is currently known about themajority of poplar species occurring in this region. In the present study, molecular data wereutilized to determine the genetic relationships among Populus species in Section Tacamahacain western Sichuan including P. cathayana, P. prezewalskii, P. yunnanensis, P. kangdingensis,P. schneideri, P. simonii and P.trinervis. The results are as fellows: 1. The genetic variation at SSR and ISSR loci was abundant. All the 10 SSR loci werepolymorphic, and the number of alleles per locus varied from 5 to 17 with a mean valueequaling 11.9. Based on the 11 ISSR primers, 130 clear and reproducible DNA fragmentswere generated, of which 119 (91.5%) were polymorphic. Our results reveal that single SSRlocus can present more genetic information, while more polymorphic bands can be detectedby single ISSR primer. Moreover, the genetic distance, cluster and PCA analysisdemonstrated that: a close relationship among accessions of the same species and suggestedmonophyly in P. przewalskii and P. cathayana; P. schneideri is genetically highly similar to P.kangdingensis; P. trinervis and P. simonii have a close genetic affinity; P. yunnanensis isdistinct from the other species. 2. Genetic relationships of poplar species in Section Tacamahaca from western Sichuanwere evaluated by means of AFLP and TE-AFLP. For four AFLP primer combinations, atotal of 284 bands were obtained of which 200 (70.4%) were polymorphic with the average of50 polymorphic bands. For four TE-AFLP primer combinations, a total of 192 band wereobtained of which 139 (72.4%) were polymorphic with the average of 34.7 polymorphicbands. Our results indicate that the genetic information of AFLP is similar to that ofTE-AFLP, and little less than that of ISSR, but only about 1/3 of that of SSR. However, theability of information detection of the two AFLP-based markers is much higher than that ofISSR and SSR. In addition, the cluster analysis of AFLP, TE-AFLP and combined data revealthat: P. yunnanensis, P. trinervis and P. simonii clustered together, and P. trinervis and P.simonii showed more closed affinity; the other four poplar species clustered together, P.cathayana and P. schneideri showed more closed origin especially. 3. The cpSSR analysis for seven Populus species belonging to the Section Tacamahaca.Four out of the seven analyzed chloroplast loci were polymorphic, whereas none of the lociwere polymorphic across the accessions within a species. 13 bands and 4 different kinds ofhaplotypes were reduced. Based on 5 pairs of cpDNA primers, 73 fragments (52 polymorphic)and 9 kinds of haplotypes were produced. However, none of the polymorphic was detected bythe 5 mtDNA primer pairs, revealing conservation of mtDNA region. The cluster analysis ofcpDNA revealed that: similar maternal phylogeny among P. yunnanensis, P. trinervis and P.simonii; the other four species clustered together, P. schneideri and P. kangdingensis showedmore closed maternal lineage especially. 4. Our molecular data, morphological characters and nature habitat revealed that: sameto the traditional taxonomy assignment, genetic variation within a same Populus species islower than that among Populus species in Section Tacamahaca; P. yunnanensis may share itschloroplast ancestor with P. trinervis and P. simonii; moreover, sister genetic relationship of P.trinervis and P. simonii indicated their similar origin; P. schneideri clustered with P.kangdingensis and P. cathayana, respectively, and may have derived from an ancienthybridization event involving the ancestors of the two species.
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棘蛙族(Tribe Paini)隶两栖纲(Amphibia)、无尾目(Anura)、蛙科(Ranidae)、叉舌蛙亚科(Dicroglossinae),由棘蛙属(Paa)、倭蛙属(Nanorana) 和沙巴蛙属(Chaparana)构成(Dubois,1992)。由于特殊的形态特征和染色体核型,棘蛙族受到国内外学者的广泛重视和研究,但是到目前为止,棘蛙族的系统发育关系尚未明晰,族下属种的分类和归属问题还有待进一步研究和新的证据出现。本文通过光学显微镜、电子显微镜和石蜡切片对棘蛙族10 物种的精子和精巢进行研究,旨在了解棘蛙族精子的形态、量度、超微结构特征及不同季节精巢结构的变化规律,同时为棘蛙族的系统研究提供新的依据,也为棘蛙族濒危物种的保护和经济物种的繁殖提供基础资料。研究结果表明:棘蛙族各属物种精子的形态基本相似,精子整体呈线形,由头部、中片和尾部构成。精子头部呈长条状,顶体呈锥状,位于头部顶端并向前伸出,中片较长,尾部波动弯曲。棘蛙族各属物种精子量度差异较大,将各属物种精子头部、中片、尾部、头宽、尾宽的量度数据进行聚类分析,结果表明棘蛙族10 物种可分为三类:第一类包括棘侧蛙、合江棘蛙、小棘蛙、棘腹蛙和棘胸蛙,特点是精子较短,全长在72.6~103.35µm 之间;第二类包括倭蛙、高山倭蛙、腹斑倭蛙,特点是精子较长,全长在107.74~129.75µm 之间;第三类包括隆肛蛙和双团棘胸蛙,特点是精子最长,全长在145.89~165.84µm 之间。棘蛙族各属精子超微结构基本相似:精子头部由顶体、细胞核构成;中片由中心粒、线粒体构成;尾部由单根轴丝构成。精子顶体横切呈圆环状,细胞核电子密度高;线粒体为卵圆形,呈环状围绕轴丝排列,线粒体数目较多,约30层;尾部轴丝为典型的9+2结构,即由2根中央微管和9对外周微管组成。不同季节的倭蛙精巢结构变化表明倭蛙精巢每年只有一个生精周期,生精周期始于7 月,繁殖季节从5 月到6 月,生精高峰期为9 月;根据倭蛙不同季节精巢结构的变化,可将生精周期分为3 个阶段:第一阶段从7 月到9 月,为精子形成期;第二阶段从10 月到翌年4 月,为精子的贮存阶段,也即倭蛙的冬眠期;第三阶段从5 月到6 月,为精子的排放阶段,即倭蛙的繁殖期。不同季节的隆肛蛙精巢结构变化表明5 月为隆肛蛙的繁殖高峰期。根据棘蛙族各属精子的形态、量度和超微结构特征,结合已有的棘蛙族形态学、生态学、染色体核型及系统学研究成果,本文认为:1.基于精子数据对棘蛙族的划分和基于形态学及分子系统学数据对棘蛙族的划分均有相同之处,精子形态结构可为棘蛙族的系统研究提供新的证据。2. 棘蛙族各属精子的形态、量度及超微结构不仅与蛙科其他属种有明显差异,而且在无尾类中也较为特殊,精子学研究结果支持将棘蛙族从蛙科中分离出来,归隶于叉舌蛙科的叉舌蛙亚科的系统学修正。3. 精子的顶体、细胞核、中片的形态结构及量度可作为蛙科的分类指标。On the base of unique morphological and kyrotype characters, Dubois(1992)recognized three genera Paa, Narnorana, Chaparana as tribe Paini, which is amember of Dicroglossinae, Ranidae. In present study, the sperm shape, size andultrastructure of 10 paini species were investigated through the light and electronmicroscope, and testis structure of N. pleskei and F. quadrana was also studied. Wesuppose this study could offer some spermatological evidence to phylogeny andreproduction study of tribe Paini. The results were as follows:The sperm shape of tribe paini is homologically similar, the spermatozoa arefiliform, composed of elongate head, long mid-piece and waved tail. The acrosome isapically associated with the nucleus and extend anteriorly.The sperm length of tribe paini differ remarkably among genera. Cluster for thelength of sperm head, mid-piece, tail, total length, head-width, tail-width of ten painifrogs indicated the 10 species could be separated into three groups: GroupⅠcontainsP. shini, P. robertingeri, P. spinosa, P. exilispinosa, P. boulengeri, the spermatozoa ischaracterized with short in total length, ranging from 72.6µm to 103.35µm; GroupⅡcontains N. pleskei, N. parkeri, N. ventripunctata, the spermatozoa ischaracterized with relatively long in total length, ranging from 107.74µm to129.75µm; Group Ⅲ contains F. quadrana and P. yunnanensis, the spermatozoa is characterized with longest in total length, ranging from 145.89µm to 165.84µm. thethree groups based on spermatological data is partially match the classification basedon morphological and molecular data.The ultrastructure of spermatozoa in tribe paini is also basic similar, includingacrosome vescile, nuleus of the head proper, centriole, mitochondriol of themid-pieces, axoneme of the tail. The acrosome vescle is circle in TEM transversesection, the density of nucleus is high; The mitochondrions is oval, surrounding theaxial filament with about 30 layers of mitochondria; The axoneme has the typical 9+2pattern of microtubules.The seasonal changes in testis of N. pleskei indicates it has only onespermatogenesis circle, which begin in July, the reproduction season is from May toJune, the spermatogenesis is active in September. On the base of seasonal changes intestis, the spermatogenesis circle can be separated into three stages: In stageⅠfromJuly to September, spermatids are formed; In stage Ⅱ from October to April next year,the spermatozoa are stored in testis,which is the hibernated period; In stage Ⅲ fromMay to June, mature spermatozoa were released from the testis, which is thereproduction season of N. pleskei. As to F. quadrana, reproduction is active in May.With the previous study of morphology, ecology, karyotypes and phylogenyresearch of tribe Paini, the spermatological data in present study suggests:1. The spermatological classification of tribe paini is partially consistant with themorphological and molecular classification respectively.2.The sperm morphology and ultrustructure of tribe paini is unique not only inthe family Ranida but also in Anura, which suggest the tribe paini is monophyletic andmight be transfered from the family Ranida to the family Dicroglossidae based onmolecular evidence.3. The acrosome, nuleus, shape, length and ultrastructure of mid-piece can beused as an alternative taxonomic character in Anura.
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利用在束γ谱学技术和173Yb(18O,4n)熔合蒸发反应研究了187Pt的高自旋态能级结构.建立了包括3个转动带的187Pt高自旋态能级纲图.基于187Pt周围核结构的系统学和比较带内B(M1)/B(E2)比率的实验值和理论值,建议上述3个转动带的组态分别为11/2+[615],7/2-[503]和1/2-[521].对各转动带的带交叉频率、顺排增益、旋称劈裂等进行了讨论.
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利用能量为 16 4— 180MeV的3 5Cl束流 ,通过14 9Sm(3 5Cl,p4n)反应研究了179Pt的高自旋态能级结构 .进行了γ射线的激发函数、X γ和γ γ t符合测量 ,建立了基于 1 2 -[5 2 1],5 2 -[5 12 ]和7 2 + [6 33]组态的 3个转动带 .实验上观测到 1 2 -[5 2 1]带在ω =0 2 7MeV附近顺排角动量突然增大 ,且 7 2 + [6 33]带具有较大的旋称劈裂 .通过比较奇APt同位素和179Pt的同中子素能级结构的系统性 ,对相关现象进行了分析和讨论 .
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利用14 MeV中子轰击天然铂靶,通过~(198)Pt(n,2p)~(197)Os反应产生锇的一种同位素~(197)Os,以γ(X)谱学方法鉴别了它,同时研究了它的衰变性质。观测到了能量为41.2、50.7、196.8、199.6、223.9、233.1、250.2、342.1、403.6和406.4keV的10条新γ射线,并指定为~(197)Os的衰变。测定它的半衰期为2.8±0.6 min。
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利用在束γ谱学方法,通过~(124)Sn(~7Li,α2n)反应研究了~(125)Sb的激发态,首次建立了~(125)Sb的高自旋能级纲图,其中包括21条新γ跃迁和14个新能级。发现1970,2110和2470 keV3个能级为同质异能态,基于延迟符合测量确定了它们的寿命范围,并确定其自旋、宇称分别为15/2~-,19/2~-和23/2~+。根据粒子-核芯耦合图像和经验壳模型计算解释了~(125)Sb的能级结构,3个同质异能态的组态分别被指定为πg_(7/2)(×)V(h_(11/2)s_(1/2))_(5~-),πg_(7/2)(×)V(h_(11/2)d_(3/2))_(7~-)和πg_(7/2)(×)V(h_(11/2)~2)_(10~+),
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介绍了在线同位素分离器使用激光离子源的重要性、激光离子源原理和相关激光技术 ,以及热毛细管激光离子源和靶室的结构 .在首次在线实验中使用 50MeV u1 8O + natTa→1 67Yb(T1 2 =1 7.5m)反应道 ,实现了加速器、分离器和激光系统的联合运行 .通过测量分离后产物的γ谱 ,确定了分离后的 1 67Yb的产额 ,并与从产生截面、束流强度、收集时间和靶厚度计算得到的产生率相比 ,得到总分离效率约为 0 .2 % .通过有激光与无激光条件下测量的γ谱中 1 67Yb与 1 67Lu相应峰下面积比值K得到元素选择性η为 3 .2 .发现了新的 1 67Yb的长寿命高自旋的同质异能态 ,分析了提高效率的途径 .
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通过熔合蒸发反应12 8Te( 19F ,4nγ)布居了143Pm的高自旋态 ,利用在束γ谱学方法 ,对143Pm的高自旋态核结构进行了研究 .测量了γ射线单谱和γ -γ符合谱 ,并进行了γ射线各向异性以及DCO比率分析 ,建立了激发能高达1 0 53 5 4keV的能级纲图 ,其中包括新发现的 3 2条γ射线和 1 7个新能级 .用弱耦合模型对143Pm的晕态能级结构进行了解释
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利用 10 2MeV16O6+束轰击同位素靶117Sn ,通过熔合蒸发 4n反应产生核素12 9Ce.由氦喷嘴快速带传输系统将反应产物送到低本底区 .通过化学分离来制备待测的Ce样品 ,与此同时用16O束轰击117Sn的两种相邻的同位素靶118Sn和116Sn ,并比较上述 3种反应中的产物来进一步区分元素Ce的不同的同位素 .结果一种半衰期为 4.1min的活性被鉴定为12 9Ce.基于X -γ -t和γ -γ -t符合测量 ,建议了包括 5 1条射线在内的12 9Ce的 (EC/ β+)衰变纲图 .其中 ,12 9Ce基态直接馈送到12 9La基态的份额 ( 2 6± 7) %是用观测到的12 9La衰变的 2 78.6keV的γ射线的生长和衰变曲线估计出来的 .另外还给出了用La Kα X射线和6 8.2keVγ射线开门的γ谱以及典型的衰变γ射线的时间谱
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介绍了一种同位旋相关的输运方程 ,研究了在入射能量为 2 8.7和 6 0 .0MeV/u时 12 C +12 C的反应 ,对模型进行检验 ,发现计算结果较好地符合实验结果 ,说明了方程的可靠性 .利用该模型研究了在入射能量为 2 8.7MeV/u下反应系统17— 2 0 ,2 2 Ne+12 C中核素19Na的产生截面 ,发现缺中子核引起的反应 ,具有更大19Na的产生截面 ,为新核素的探测找到了理论依据 .
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We briefly introduce the current status and progress in the field of radioactive ion beam physics and the study of super-heavy nuclei. Some important problems and research directions are outlined, such as the sub-barrier fusion reaction, the direct reaction at Fermi energy and high energies, the property of nuclei at drip-lines, new magic numbers and new collective motion modes for unstable nuclei and the synthesis and study of the super-heavy nuclei.
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High-spin states in Pt-187 have been studied experimentally using the Yb-173(O-18, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the nu i(13/2),nu 7/2(-)[503], and nu i(13/2)(2)nu j configurations have been extended to high-spin states, and new rotational bands associated with the nu 3/2(-)[512] and nu 1/2(-)[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus Pt-187 is very soft with respect to beta and gamma deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i(13/2) neutrons or of h(9/2) protons. Importantly, evidence is presented for a pi h(9/2) alignment at very low frequency in the nu 7/2(-)[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I -> I-1)/B(E2;I -> I-2) ratios with the theoretical values from the semiclassical Donau and Frauendof approach.
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The high-spin states in Pt-187 have been studied experimentally by means of in-beam gamma-ray spectroscopy techniques via the Yb-173(O-18, 4n) fusion-evaporation reaction. The high-spin level scheme of Pt-187 has been established, including three rotational bands. Based on the systematics of level structure in neighboring nuclei and by comparing the experimental and theoretical B(M1)/B(E2) ratios, configurations of 11/2+ [615], 7/2(-)[5031 and 1/2(-)[521] have been proposed for the three rotational bands, respectively. Band properties of band crossing frequency, alignment gain and signature splitting have been discussed.
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本论文分为两部分,分别沿自旋和同位旋自由度开展研究工作。第一部分介绍原子核高自旋态研究的相关背景知识、基础理论等,描述在束γ谱学研究的实验技术和方法,分析和讨论形变核179Pt转动带能级结构的特性,并采用相关理论对其进行分析。通过融合蒸发反应149sm(35cl,P4n)布居奇A核179Pt的高自旋激发态。指认179Pt的组态为1/2-[521],5/2-[512〕和7/2+〔633〕的三条转动带。在hco=0.27 Mev附近,观测到1/2-〔521]带内顺排角动量突然增大,建议该现象是由一对113/2中子发生顺排造成的。另外观察到在7/2+〔633]带中出现较大的旋称劈裂。建议由于三轴形变加强了波函数中来自几=1/2轨道的组分,从而导致较大的旋称劈裂的出现。论文第二部分介绍重丰中子核衰变性质研究以及新核素合成、鉴别工作的相关背景知识、理论基础及实验技术。并对相关的研究工作分别进行阐述。通过快中子反应合成并鉴别了新核素19705和新的同核异能素186rnTa,利用γ(x)谱学方法首次建立了19705的部分衰变纲图。测得它们的半衰期分别为2.8士0.6 min和1.50.1 min,并与理论计算结果进行了比较;进行了原子核基态β延发裂变(pDF)的实验研究,经测量首次发现了230Ac的两个pDF事件,测得23OAc的pDF几率为(1.19±0.40)
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利用重离子辐照技术对甜高粱种子进行不同剂量的诱变处理,并分析辐照后代的农艺性状、生理生化特性及基因组DNA的多态性差异,旨在选育出含糖量高、生物量高及抗逆性强的新品种,为发展生物质燃料乙醇产业提供优质的原料,并阐明重离子对甜高粱的诱变机理。主要结果如下: 1.甜高粱在田间的存活曲线表现为“类马鞍型”,随着辐照剂量的增加,其存活率先降后升再下降。 2.筛选出株高、单秆重、糖锤度、早熟型、茎粗等突变类型的材料,尤其是80Gy辐照剂量下从BJ0602中得到的早熟突变材料KFJT-1,生育期缩短了20天左右。 3.和未辐照株KFJT-CK相比,辐照突变株KFJT-1的萌芽指标表现为极显著差异(p<0.01),其发芽势、发芽指数、活力指数和子叶长度、胚根鲜重及子叶鲜重分别下降了24%、12.69%、0.8108%和15.32%、76.27%、27.08%。 4. 利用RAPD技术对不同剂量的辐照处理检测出的多态性差异表明,不同剂量的碳离子束辐照后,不同辐照剂量对应的5种处理材料的DNA突变率分别0%、11.4%、12.2%、18.7%和17.7%。 重离子辐照可引起甜高粱各个方向的突变,有些突变材料生物量和含糖量均高,而有些突变材料表现出生长点消失、叶片扭曲、黄化等表型性状