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Crypton transposons: identification of new diverse families and ancient domestication events
Kenji K Kojima, Jerzy Jurka
Mobile DNA , 2011, DOI: 10.1186/1759-8753-2-12
Abstract: Herein we report new Cryptons from animals, fungi, oomycetes and diatom, as well as widely conserved genes derived from ancient Crypton domestication events. Phylogenetic analysis based on the YR sequences supports four deep divisions of Crypton elements. We found that the domain of unknown function 3504 (DUF3504) in eukaryotes is derived from Crypton YR. DUF3504 is similar to YR but lacks most of the residues of the catalytic tetrad (R-H-R-Y). Genes containing the DUF3504 domain are potassium channel tetramerization domain containing 1 (KCTD1), KIAA1958, zinc finger MYM type 2 (ZMYM2), ZMYM3, ZMYM4, glutamine-rich protein 1 (QRICH1) and "without children" (WOC). The DUF3504 genes are highly conserved and are found in almost all jawed vertebrates. The sequence, domain structure, intron positions and synteny blocks support the view that ZMYM2, ZMYM3, ZMYM4, and possibly QRICH1, were derived from WOC through two rounds of genome duplication in early vertebrate evolution. WOC is observed widely among bilaterians. There could be four independent events of Crypton domestication, and one of them, generating WOC/ZMYM, predated the birth of bilaterian animals. This is the third-oldest domestication event known to date, following the domestication generating telomerase reverse transcriptase (TERT) and Prp8. Many Crypton-derived genes are transcriptional regulators with additional DNA-binding domains, and the acquisition of the DUF3504 domain could have added new regulatory pathways via protein-DNA or protein-protein interactions.Cryptons have contributed to animal evolution through domestication of their YR sequences. The DUF3504 domains are domesticated YRs of animal Crypton elements.The structural and mechanistic variety of transposable elements (TEs) is well-documented [1]. They encode proteins that include diverse functional domains involved in catalysis or interaction with DNA, RNA and other proteins. Because of this diverse repertoire, TEs can supply functional modules
击顶制导  [PDF]
兵工学报 , 1992,
Abstract: ?论述了反坦克导弹精确制导发展的一个重要问题:击顶制导。给出了准三点导引法和适用于遥控反坦克导弹的掠飞击顶制导律;准比例导引法和适用于自寻的反坦克导弹的俯冲击顶制导律;以及实现上述两种击顶制导律的三通道参数最优击顶数字控制器。
浸水对击实黄土的压缩变形影响的试验研究
Experimental Study on Compression Deformation of Compacted
 [PDF]

杨晶,邓美林,白晓红
- , 2017,
Abstract: 摘要 回填地基或路基在施工运营后产生沉降变形往往与浸水有关。通过对轻型和重型击实黄土的试验研究,分析比较了浸水和不浸水条件下击实黄土的压缩变形随压力变化的规律,定义了浸水压缩变形影响系数,通过该系数反映击实黄土的水稳定性,结果表明,重型击实土的水稳定性优于轻型击实土,当击实土的含水量为相应击实能对应的最优含水量时,无论是轻型击实土或是重型击实土均表现良好的水稳定性;含水量低于最优含水量时,压实黄土遇水膨胀软化,水稳定性差;含水量高于最优含水量时,压实黄土遇水不膨胀,但浸水压缩变形影响系数仍较最优含水量试样的值要大些。
直接水击公式研究  [PDF]
马跃先,周琼,李世英,吴昊
人民黄河 , 2007,
Abstract: ?对joukowsky水击公式推导过程进行了分析,认为其推导过程中忽略了不该忽略的二阶微量.以动量定理为基础建立微分方程,考虑水体可压缩性和管壁弹性,得到不同于joukowsky水击公式的直接水击公式,与相关研究文献进行比较后认为,所建公式比joukowsky公式更合理.
悼楊樹达(遇夫)先生  [PDF]
罗常培
科学通报 , 1956,
Abstract: 自从1937年我和遇夫先生分手后,我們离別已經20年了。去年10月間,遇夫先生來北京出席現代漢語規范問題学術会議,我們才重新見了面。
悼楊樹达(遇夫)先生
罗常培
科学通报 , 1956,
Abstract: 自从1937年我和遇夫先生分手后,我們离別已經20年了。去年10月間,遇夫先生來北京出席現代漢語規范問題学術会議,我們才重新見了面。从外表上看起來,他是顯得有些蒼老,可是看他那么健談,追敘我們当年在清華大学同事时的一些瑣
周期受击简谐振子系统的经典与量子动力学  [PDF]
杨双波,韦栋
南京师范大学学报(自然科学版) , 2011,
Abstract: 研究一个周期受击简谐振子系统的经典与量子动力学.研究发现,随着打击强度κ的增加,经典相空间发生分形时,一步时间演化算符的本征值分布也从单位圆的圆周上朝着圆心扩散.而当本征值归一化后,归一化后的本征值分布又回到单位圆周上.
攻顶反坦克武器威力与精度分析  [PDF]
宋振铎
兵工学报 , 1992,
Abstract: ?计算了攻顶反坦克弹在两类典型目标上的分布,提出了巡航、曲射与抛散弹道威力要求的计算式,分析了攻顶武器射击精度的要求。
乒乓球直拍反手反面攻新技术  [PDF]
马铭宏?
天津体育学院学报 , 1993,
Abstract: 乒乓球直拍反手反面攻新技术,包括:反面快拔、反面攻球、反面弧圈、反面挑近网短球.动作结构合理、简炼,易于掌握。
稳定的常遇洪水是推求稀遇洪水的基础  [PDF]
慕平,关红兵,夏燕青
人民黄河 , 2007,
Abstract: ?较短实测洪水系列中的最大洪水属不稳定频率点据,尤其是特大值的重现期不易准确确定,若在频率适线时明显脱离多数实测洪水点据,按不确定、不稳定的特大洪水或实测最大洪水的频率点据定线,则由此推算的稀遇洪水偏差较大.当洪水系列达到一定长度、洪水系列中20年一遇以下的常遇洪水相对趋于稳定时,联动调整洪水系列的均值、cv、cs/cv,使理论频率曲线基本上通过较稳定的洪水频率点据,由此外延推估稀遇洪水,其稳定性、可靠性将增大.
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