convergence

收敛性
  • 文章类型: Journal Article
    强制性宿主限制细菌的基因组遭受积累的轻度有害突变,导致明显的尺寸减小。半翅目是韧皮部吸液昆虫,具有称为细菌组的专门器官,通常包含两个垂直传播的细菌共生体:主要共生体“CandidatusCarsonellaruddii”(Gammaproteobacteria)和次要共生体,该共生体在木虱谱系中具有系统发育多样性。发现几种Carsonella谱系的基因组显着减少(158-174kb),富AT(14.0-17.9%GC),在结构上具有相似的基因库存,专门用于合成韧皮部汁液中稀缺的必需氨基酸。然而,目前在次级共生体上可获得的基因组信息有限。因此,本研究调查了与细菌组相关的双共生体的基因组,二级_AM(伽玛变形杆菌)和Carsonella_AM,在桑树木霉科(Psyllidae)中。获得的结果表明,二级AM基因组小且富含AT(229,822bp,17.3%GC)如卡森氏菌谱系,包括Carsonella_AM(169,120bp,16.2%GC),暗示二级AM是一个进化上古老的义务互助者,Carsonella也是.系统发育学分析表明,次生_AM是Cacopsylaspp的“CandidatusPsylllophilasybiotica”的姐妹。(Psyllidae),最近报道的基因组(221-237GB,17.3-18.6%GC)。次级_AM和Psylophila基因组显示出高度保守的同系性,共享所有基因,以补充Carsonella的不完全色氨酸生物合成途径和合成B族维生素的基因。然而,硫同化和类胡萝卜素合成基因仅保留在次级_AM和Psyllophia中,分别,表明正在进行的基因沉默。平均核苷酸同一性,基因直系同源相似性,全基因组同伦,和替代率表明,次级AM/Psyllophia基因组比卡森氏菌基因组更不稳定。
    The genomes of obligately host-restricted bacteria suffer from accumulating mildly deleterious mutations, resulting in marked size reductions. Psyllids (Hemiptera) are phloem sap-sucking insects with a specialized organ called the bacteriome, which typically harbors two vertically transmitted bacterial symbionts: the primary symbiont \"Candidatus Carsonella ruddii\" (Gammaproteobacteria) and a secondary symbiont that is phylogenetically diverse among psyllid lineages. The genomes of several Carsonella lineages were revealed to be markedly reduced (158-174‍ ‍kb), AT-rich (14.0-17.9% GC), and structurally conserved with similar gene inventories devoted to synthesizing essential amino acids that are scarce in the phloem sap. However, limited genomic information is currently available on secondary symbionts. Therefore, the present study investigated the genomes of the bacteriome-associated dual symbionts, Secondary_AM (Gammaproteobacteria) and Carsonella_AM, in the mulberry psyllid Anomoneura mori (Psyllidae). The results obtained revealed that the Secondary_AM genome is as small and AT-rich (229,822 bp, 17.3% GC) as those of Carsonella lineages, including Carsonella_AM (169,120 bp, 16.2% GC), implying that Secondary_AM is an evolutionarily ancient obligate mutualist, as is Carsonella. Phylogenomic ana-lyses showed that Secondary_AM is sister to \"Candidatus Psyllophila symbiotica\" of Cacopsylla spp. (Psyllidae), the genomes of which were recently reported (221-237‍ ‍kb, 17.3-18.6% GC). The Secondary_AM and Psyllophila genomes showed highly conserved synteny, sharing all genes for complementing the incomplete tryptophan biosynthetic pathway of Carsonella and those for synthesizing B vitamins. However, sulfur assimilation and carotenoid-synthesizing genes were only retained in Secondary_AM and Psyllophila, respectively, indicating ongoing gene silencing. Average nucleotide identity, gene ortholog similarity, genome-wide synteny, and substitution rates suggest that the Secondary_AM/Psyllophila genomes are more labile than Carsonella genomes.
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  • 文章类型: Journal Article
    超过一百个风险基因是自闭症谱系障碍(ASD)风险的基础,但它们在多大程度上聚集在共享的下游目标上以增加ASD风险尚不清楚。为了检验细胞环境影响收敛性质的假设,在这里,我们应用一种混合的CRISPR方法来靶向人类诱导多能干细胞(hiPSC)衍生的神经祖细胞中的29个ASD功能丧失基因,谷氨酸能神经元,和GABA能神经元。两种不同的方法(基因水平和网络水平分析)表明,在成熟的谷氨酸能神经元中收敛最大。收敛效应是动态的,强度不同,composition,和细胞类型之间的生物学作用,随着所检查的ASD基因的功能相似性的增加,并由细胞类型特异性基因共表达模式驱动。ASD基因的分层产生了靶向药物预测,能够逆转人细胞中基因特异性趋同特征和斑马鱼中ASD相关行为。总之,ASD风险基因下游的聚合网络代表了个性化治疗干预的新观点。
    Over a hundred risk genes underlie risk for autism spectrum disorder (ASD) but the extent to which they converge on shared downstream targets to increase ASD risk is unknown. To test the hypothesis that cellular context impacts the nature of convergence, here we apply a pooled CRISPR approach to target 29 ASD loss-of-function genes in human induced pluripotent stem cell (hiPSC)-derived neural progenitor cells, glutamatergic neurons, and GABAergic neurons. Two distinct approaches (gene-level and network-level analyses) demonstrate that convergence is greatest in mature glutamatergic neurons. Convergent effects are dynamic, varying in strength, composition, and biological role between cell types, increasing with functional similarity of the ASD genes examined, and driven by cell-type-specific gene co-expression patterns. Stratification of ASD genes yield targeted drug predictions capable of reversing gene-specific convergent signatures in human cells and ASD-related behaviors in zebrafish. Altogether, convergent networks downstream of ASD risk genes represent novel points of individualized therapeutic intervention.
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  • 文章类型: Journal Article
    对颌骨脊椎动物(gnathostomes)抗体的研究为每个免疫学家提供了人类免疫球蛋白(Igs)如何存在并随后演变成其现有形式的鸟瞰。一方面是一个迷人的达尔文保护历史,另一方面是灵活性,以Ig重链(H)同种型IgM和IgD/W为例,分别。软骨鱼(例如,鲨鱼)Igs提供了“一切是如何离开地面的,\“而两栖动物(例如,Xenopus模型)揭示了适应性免疫系统如何随着Ig同种型转换和IgG样结构/功能的出现而产生变化。粘膜Igs的进化是对延展性的迷人解释,收敛,和保护,并呼吁未来的研究!在这两者之间有关于每一类脊椎动物抗体进化的引人入胜的编年史,以及抗体如何适应占据生态位的令人难以置信的故事,例如,单结构域可变区,冷适应的Ig,抑制抗体功能的汇聚机制,提供粘膜防御,还有更多。这里的目的不是提供抗体进化的百科全书式检查,而是要达到高点,吸引读者欣赏“事物”的出现。\"
    The study of antibodies in jawed vertebrates (gnathostomes) provides every immunologist with a bird\'s eye view of how human immunoglobulins (Igs) came into existence and subsequently evolved into their present forms. It is a fascinating Darwinian history of conservation on the one hand and flexibility on the other, exemplified by the Ig heavy chain (H) isotypes IgM and IgD/W, respectively. The cartilaginous fish (e.g., sharks) Igs provide a glimpse of \"how everything got off the ground,\" while the amphibians (e.g., the model Xenopus) reveal how the adaptive immune system made an about face with the emergence of Ig isotype switching and IgG-like structure/function. The evolution of mucosal Igs is a captivating account of malleability, convergence, and conservation, and a call to arms for future study! In between there are spellbinding chronicles of antibody evolution in each class of vertebrates and rather incredible stories of how antibodies can adapt to occupy niches, for example, single-domain variable regions, cold-adapted Igs, convergent mechanisms to dampen antibody function, provision of mucosal defense, and many more. The purpose here is not to provide an encyclopedic examination of antibody evolution, but rather to hit the high points and entice readers to appreciate how things \"came to be.\"
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  • 文章类型: Journal Article
    复值卷积神经网络(CVCNN)已被证明在对复杂信号和合成孔径雷达(SAR)图像进行分类方面的有效性。然而,由于引入了复值参数,CVCNNs往往变得冗余,浮点运算繁重。模型稀疏性是一种有效的方法,可以消除冗余而不会损失太多性能。目前,关于CVCNN稀疏性问题的研究很少。因此,针对稀疏CVCNN的设计,提出了一种复值软对数阈值重加权(CV-SLTR)算法,以减少权重参数的数量,简化CVCNN的结构。一方面,考虑到复数和实数之间的区别,我们重新定义和推导了复值对数和阈值方法。另一方面,通过考虑CVCNNs的复值卷积(CConv)层和复值全连接(CFC)层的独特特征,分别开发了复值软和对数和阈值方法,以在前向传播过程中修剪不同层的权重,并且在后向传播期间通过引入稀疏度预算来优化稀疏度阈值。此外,不同的优化器可以与CV-SLTR集成。当使用随机梯度下降(SGD)时,如果满足Lipschitzian连续性,则证明了CV-SLTR的收敛性。在RadioML2016.10A和S1SLC-CVDL数据集上的实验表明,该算法对CVCNN的稀疏性有效。值得注意的是,该算法在保持较高分类精度的同时,具有较快的稀疏性速度。这些证明了CV-SLTR算法的可行性和潜力。
    Complex-valued convolutional neural networks (CVCNNs) have been demonstrated effectiveness in classifying complex signals and synthetic aperture radar (SAR) images. However, due to the introduction of complex-valued parameters, CVCNNs tend to become redundant with heavy floating-point operations. Model sparsity is emerged as an efficient method of removing the redundancy without much loss of performance. Currently, there are few studies on the sparsity problem of CVCNNs. Therefore, a complex-valued soft-log threshold reweighting (CV-SLTR) algorithm is proposed for the design of sparse CVCNN to reduce the number of weight parameters and simplify the structure of CVCNN. On one hand, considering the difference between complex and real numbers, we redefine and derive the complex-valued log-sum threshold method. On the other hand, by considering the distinctive characteristics of complex-valued convolutional (CConv) layers and complex-valued fully connected (CFC) layers of CVCNNs, the complex-valued soft and log-sum threshold methods are respectively developed to prune the weights of different layers during the forward propagation, and the sparsity thresholds are optimized during the backward propagation by inducing a sparsity budget. Furthermore, different optimizers can be integrated with CV-SLTR. When stochastic gradient descent (SGD) is used, the convergence of CV-SLTR is proved if Lipschitzian continuity is satisfied. Experiments on the RadioML 2016.10A and S1SLC-CVDL datasets show that the proposed algorithm is efficient for the sparsity of CVCNNs. It is worth noting that the proposed algorithm has fast sparsity speed while maintaining high classification accuracy. These demonstrate the feasibility and potential of the CV-SLTR algorithm.
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  • 文章类型: Journal Article
    背景:研究与基础间歇性外斜视(IXT)患者的调节和收敛以及轴向伸长相关的参数之间的关联,以及轴向长度(AL)增长的潜在临床预测因子。
    方法:本研究共招募140名基础IXT患者。选择不同年龄段AL生长的中位数,将受试者分为A组(轴向伸长较慢组,n=69)和B组(轴向伸长较快的组,n=71)。在12个月的随访期间,比较和分析了显性和非显性眼的参数。参数,包括基线折射,偏差角,纽卡斯尔得分(NCS),调节振幅(AMP),住宿设施(AMF),宽松的反应,正或负相对调节(PRA/NRA),和近收敛点(NPC),通过单因素和多因素回归分析。
    结果:轴向伸长较快组的受试者倾向于具有更多的近视球面当量(t=3.956,P<.001),优势眼的调节幅度更大(t=-2.238,P=.027),近收敛点(t=2.347,P=.020)比轴向伸长较慢组。对于占优势的眼睛,Logistic和线性回归分析显示,较多的负球形当量(OR=0.603,P<.001;β=-0.045,P<.001),较大的调节幅度(OR=1.201,P=.027;β=0.023,P=.010)和较小的收敛点(OR=0.883,P=.021;β=-0.012,P=.019)与较快的轴向伸长率相关。对于非占优势的眼睛,通过回归分析,更近视的球面当量(OR=0.682;P=.001;β=-0.029,P=.005)是与更快的轴向伸长率相关的唯一参数。
    结论:在患有基本间歇性外斜视的儿童中,优势眼中更快的轴向伸长与更近视的球面等效物有关,更大的调节振幅,和较低的收敛点附近。除了眼轴长度之外,这些调节参数可以用作监测近视进展的潜在临床指标。
    BACKGROUND: The aim of the study was to investigate the association of parameters related to accommodation and convergence and axial elongation in basic intermittent exotropia (IXT) patients and the potential clinical predictors of axial length (AL) growth.
    METHODS: A total of 140 basic IXT patients were recruited in this study. The medians of AL growth in different age brackets were chosen to divide the subjects into group A (slower axial elongation group, n = 69) and group B (faster axial elongation group, n = 71). Parameters of dominant and nondominant eyes were compared and analyzed during the 12-month follow-up period. The parameters, including baseline refraction, angle of deviation, Newcastle control score (NCS), accommodative amplitude (AMP), accommodative facility (AMF), accommodative response, positive or negative relative accommodation (PRA/NRA), and near point of convergence (NPC), were analyzed via univariate and multivariate regression.
    RESULTS: Subjects in the faster axial elongation group tended to have more myopic spherical equivalents (t = 3.956, p < 0.001), greater AMPs of dominant eyes (t = -2.238, p = 0.027), and fewer near points of convergence (t = 2.347, p = 0.020) than in the slower axial elongation group. For dominant eyes, logistic and linear regression analysis revealed that more negative spherical equivalents (OR = 0.603, p < 0.001; β = -0.045, p < 0.001), greater AMPs (OR = 1.201, p = 0.027; β = 0.023, p = 0.010), and less near points of convergence (OR = 0.883, p = 0.021; β = -0.012, p = 0.019) were correlated with the faster axial elongation. For nondominant eyes, a more myopic spherical equivalent (OR = 0.682; p = 0.001; β = -0.029, p = 0.005) was the only parameter correlated with faster axial elongation through regression analysis.
    CONCLUSIONS: In children with basic IXT, faster axial elongation in the dominant eyes was associated with more myopic spherical equivalents, greater AMPs, and lower NPCs. These accommodative parameters can serve as potential clinical indicators for monitoring myopia progression in addition to AL.
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  • 文章类型: Journal Article
    我们引入了一个分析方法框架,该框架使用基准方法,尤其是链网络DEA技术,将2000-2018年期间199个欧洲地区的知识生成效率与经济效率以及相应的环境影响联系起来。在知识生成效率和生产绩效之间存在明显的权衡。与其他地区相比,表现出高创新效率的欧洲地区享有更高的整体绩效。在第二阶段,我们针对估计效率的所有三个方面调查了被检查区域的收敛模式,其中揭示了多类型收敛俱乐部的共存。
    We introduce an analytical methodological framework that links knowledge generation efficiency with economic efficiency and the corresponding environmental impact for 199 European Regions during 2000-2018, using a benchmarking approach and especially a chain network DEA technique. A clear trade-off between knowledge generation efficiency and productive performance emerges. European regions which exhibit high innovation efficiency enjoy higher overall performance compared to their counterparts. In a second stage, we investigate the convergence patterns of the examined regions with respect to all the three facets of the estimated efficiency where the coexistence of multi-type convergence clubs is revealed.
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  • 文章类型: Journal Article
    构建了求解凸二次多目标规划问题(CQMPP)的神经网络模型。首先通过加权和方法将CQMPP转换为等效的单目标凸二次规划问题,其中帕累托最优解(POS)是通过使权重值多样化来给出的。然后,对于给定的各种值权重,采用多投影神经网络搜索Pareto最优解。基于李雅普诺夫理论,所提出的神经网络方法在Lyapunov的意义上是稳定的,并且全局收敛到单目标问题的精确最优解。仿真结果也表明了该模型的可行性和有效性。
    A neural network model is constructed to solve convex quadratic multi-objective programming problem (CQMPP). The CQMPP is first converted into an equivalent single-objective convex quadratic programming problem by the mean of the weighted sum method, where the Pareto optimal solution (POS) are given by diversifying values of weights. Then, for given various values weights, multiple projection neural networks are employded to search for Pareto optimal solutions. Based on employing Lyapunov theory, the proposed neural network approach is established to be stable in the sense of Lyapunov and it is globally convergent to an exact optimal solution of the single-objective problem. The simulation results also show that the presented model is feasible and efficient.
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  • 文章类型: Journal Article
    农业劳动力向非农部门的转移与中国经济发展同步,导致劳动力成本相对于资本的大幅上升。因此,农业生产已经向资本密集型做法转变。资本深化与中国粮食产量的大幅增加相吻合,而中国粮食产量中资本深化的主要原因却知之甚少。本研究考察了各种资本投资的增加对中国主产区粮食产量增长和增长收敛的影响。基于从农产品成本效益数据汇编(CCBDAP)数据集中收集的数据。结果表明,化肥用量的增加,农药和机械投入对粮食增产起到了关键作用。对于早稻,粳稻,小麦和玉米,平均土地产出具有β收敛。这些发现表明,更多的资本投资应该加速单位土地粮食产量的增长,以实行耕地占补跨省均衡制度为契机。此外,建议对粮食种植空间分布进行战略调整,以最大限度地利用有限的耕地资源,同时坚持国家粮食安全目标。
    The shift of agricultural labor force to non-agricultural sectors has paralleled China\'s economic development, leading to a substantial rise in labor costs relative to capital. Consequently, the agricultural production has witnessed a shift towards capital-intensive practices. The capital deepening coincides with the significant increase in China\'s grain output while the main cause of capital deepening in China\'s grain production is poorly understood. This study examines the effect of increasing in various capital investments on the grain yield growth and growth convergence in China\'s main production areas, based on the data collected from the data set of the Compilation of Cost-Benefit Data of Agricultural Products (CCBDAP). Results show that the increases of chemical fertilizer, pesticide and machinery input have played key roles in the increase of grain yield. For early indica rice, japonica rice, wheat and maize, the average land output bears a β convergence. These findings suggest that more capital investments are supposed to accelerate the growth of grain yield per unit of land, take the opportunity of practicing the cross-provincial balance system of occupation and compensation of cultivated land. Moreover, strategic adjustments to the spatial distribution of grain cultivation are recommended to maximize the utilization of limited arable land resources while upholding national food security objectives.
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  • 文章类型: Journal Article
    作为网罗的蜘蛛网是最迷人和丰富的动物建筑类型之一。在许多情况下,它们包括丝线的粘合剂涂层-所谓的粘性丝-用于捕获猎物。从形成固体纤维的丝分泌物到柔软的水性粘合剂的进化转变仍然是理解蜘蛛丝进化的一个悬而未决的问题。在这里,我们在功能和化学上对两种类型的丝腺的分泌物及其在地窖蜘蛛中的行为使用进行了表征,蝴蝶兰。两者都来自相同的祖先腺体类型,该类型产生带有固化胶水涂层的纤维,这两种类型分别产生一种快速凝固的胶水,应用在螺纹锚固和猎物包裹上,或部署在网罗中的永久粘性胶水。我们发现,后者的特点是高浓度的有机盐和减少的脊髓素含量,通过吸湿盐介导的固化粘合剂的水合作用,揭示了粘滞特性演变的可能途径。了解材料特性中这种自由基转换的潜在分子基础不仅有助于更好地理解生态影响的蜘蛛网结构的进化起源和多功能性。而且还告知具有定制特性的蜘蛛丝基产品的生物工程。
    Spider webs that serve as snares are one of the most fascinating and abundant type of animal architectures. In many cases they include an adhesive coating of silk lines-so-called viscid silk-for prey capture. The evolutionary switch from silk secretions forming solid fibres to soft aqueous adhesives remains an open question in the understanding of spider silk evolution. Here we functionally and chemically characterized the secretions of two types of silk glands and their behavioural use in the cellar spider, Pholcus phalangioides. Both being derived from the same ancestral gland type that produces fibres with a solidifying glue coat, the two types produce respectively a quickly solidifying glue applied in thread anchorages and prey wraps, or a permanently tacky glue deployed in snares. We found that the latter is characterized by a high concentration of organic salts and reduced spidroin content, showing up a possible pathway for the evolution of viscid properties by hygroscopic-salt-mediated hydration of solidifying adhesives. Understanding the underlying molecular basis for such radical switches in material properties not only helps to better understand the evolutionary origins and versatility of ecologically impactful spider web architectures, but also informs the bioengineering of spider silk-based products with tailored properties.
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  • 文章类型: Journal Article
    Eurypterids-古生代海洋和淡水节肢动物,通常被称为海蝎子-反复进化到显着的大小(长度超过0.5m),并多次定居大陆水生栖息地。我们汇总了大多数eurypterid物种的数据,并探索了先前提出的对该群体中巨型进化的几种解释,包括栖息地的潜在作用,海面温度和溶解的海面氧水平,使用一种新的尖端树的系统发育比较方法。没有令人信服的证据表明巨大尺寸的演变是由温度或氧气水平驱动的,也没有加上大陆水生环境的入侵,纬度或当地动物区系多样性。Eurypterid体型大小演变的最佳特征是与栖息地或环境条件无关的快速变化。内在因素在确定大型龙的融合起源中起着重要作用。
    Eurypterids-Palaeozoic marine and freshwater arthropods commonly known as sea scorpions-repeatedly evolved to remarkable sizes (over 0.5 m in length) and colonized continental aquatic habitats multiple times. We compiled data on the majority of eurypterid species and explored several previously proposed explanations for the evolution of giant size in the group, including the potential role of habitat, sea surface temperature and dissolved sea surface oxygen levels, using a phylogenetic comparative approach with a new tip-dated tree. There is no compelling evidence that the evolution of giant size was driven by temperature or oxygen levels, nor that it was coupled with the invasion of continental aquatic environments, latitude or local faunal diversity. Eurypterid body size evolution is best characterized by rapid bursts of change that occurred independently of habitat or environmental conditions. Intrinsic factors played a major role in determining the convergent origin of gigantism in eurypterids.
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