Pattern formation

图案形成
  • 文章类型: Journal Article
    最近的结果通过混沌参数证明了混合系统中量子混沌的动力学特性,并在凝聚的影响下探测了模式的形成。通过数值模拟确定了所考虑系统的复杂动态行为,并提出了一种有效的技术,该技术研究了包含混沌相干分数的分数系统。这些发现揭示了相干结构与有限相对矩的相关性之间的特殊关联。因此,本研究有助于探索部分混沌混合系统,以激发非线性现象的实验应用。可以通过检查与凝结物具有明确关系的混沌特性来测量相干混沌参数,以证明物理系统的周围环境。我们研究了多重性的影响,混乱,非线性系统在相干-混沌归一化相关性上的动量和温度。相干分数大大抑制了混沌参数,并且在最大冷凝时数字上为零,在理想混沌发射时数字上为零。我们发现,有意义的参数随着非线性系统的多重性而显着减少,并且随着指定状态下的动量而增加。相同的多重性导致考虑相干性,因此其壮观影响内的归一化混沌参数表现出值得认真考虑的意义。这些发现强调了协调相关性在破译非线性系统特征并将非凡的感知赋予复杂系统的复杂本质方面的重要性。预期的方法可以应用于评估和分析非线性系统,这种创新的方法可以计算天体力学的问题,在工程和医疗领域的心跳和化学反应。
    Recent results demonstrate the dynamical peculiarities of the quantum chaos within the hybrid systems by chaotic parameters and probe the pattern formation under the influence of condensation. The complex dynamic behavior of the considered systems was determined with numerical simulation and presented an efficient technique that studied fractional systems comprising chaos-coherence fractions. The findings divulge the peculiar association between the coherence structure and the correlations at finite relative momenta. Thus the present study helps to explore the partially chaos hybrid systems in order to stimulate the experimental applications of nonlinear phenomena. The coherent-chaotic parameters can be measured by examining the chaos peculiarities that possess explicit relations with the condensations to demonstrate the environs of the physical systems. We investigate the influence of the multiplicities, chaos, momentum and temperature of the nonlinear system on the coherent-chaotic normalized correlations. The chaotic parameters are suppressed considerably with the coherence fraction and it appears numerically zero at maximum condensation and one at ideal chaos emissions. We procure that the meaningful parameters decrease significantly with the multiplicity of the nonlinear systems and increase with the momentum in the specified regimes. The identical multiplicity leads to contemplating the coherence and thus the normalized chaotic parameters within its spectacular influences exhibit significance worth contemplating in earnest. The findings underscore the significance of cogitating correlations in deciphering the nonlinear system characteristics and bestowing extraordinary perceptiveness into the convoluted essence of complex systems. The contemplated methodology can be applied to evaluating and analyzing the nonlinear systems and such an innovative approach computes the problems of celestial mechanics, heartbeats and chemical reactions in engineering and medical fields.
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  • 文章类型: Journal Article
    在生物学中,进化博弈论模型经常出现,其中玩家的策略会影响环境状态,策略和周围环境之间的驱动反馈。在这种情况下,合作相互作用可以应用于研究生态系统,动物或微生物种群,和从环境中产生或积极提取生长资源的细胞。我们考虑了具有复制动力学和人口成员从某些外部来源提取的限制增长的公共物品的生态进化博弈论框架。众所周知,合作者和叛逃者的两个子群体可以发展时空模式,从而在共享环境中实现长期共存。调查这一现象并揭示维持合作的机制,我们分析了两种生态进化模型:良好混合的环境和具有空间扩散的异质模型。在后者中,我们将空间扩散整合到复制子动力学中。我们的发现揭示了丰富的战略动态,包括双稳态和分叉,在时间系统和空间稳定性方面,以及图灵不稳定,图灵-霍普夫分叉,扩散系统中的混沌。结果表明,促进合作的有效机制包括增加玩家密度,减少相对时间尺度,控制初始合作者的密度,提高公共产品的扩散率,降低合作者的扩散速率,并提高对合作者的回报。我们提供存在的条件,稳定性,以及两个系统中分叉的发生。我们的分析可以应用于人类决策等领域的动态现象,微生物生长因子分泌,集体狩猎。
    In biology, evolutionary game-theoretical models often arise in which players\' strategies impact the state of the environment, driving feedback between strategy and the surroundings. In this case, cooperative interactions can be applied to studying ecological systems, animal or microorganism populations, and cells producing or actively extracting a growth resource from their environment. We consider the framework of eco-evolutionary game theory with replicator dynamics and growth-limiting public goods extracted by population members from some external source. It is known that the two sub-populations of cooperators and defectors can develop spatio-temporal patterns that enable long-term coexistence in the shared environment. To investigate this phenomenon and unveil the mechanisms that sustain cooperation, we analyze two eco-evolutionary models: a well-mixed environment and a heterogeneous model with spatial diffusion. In the latter, we integrate spatial diffusion into replicator dynamics. Our findings reveal rich strategy dynamics, including bistability and bifurcations, in the temporal system and spatial stability, as well as Turing instability, Turing-Hopf bifurcations, and chaos in the diffusion system. The results indicate that effective mechanisms to promote cooperation include increasing the player density, decreasing the relative timescale, controlling the density of initial cooperators, improving the diffusion rate of the public goods, lowering the diffusion rate of the cooperators, and enhancing the payoffs to the cooperators. We provide the conditions for the existence, stability, and occurrence of bifurcations in both systems. Our analysis can be applied to dynamic phenomena in fields as diverse as human decision-making, microorganism growth factors secretion, and group hunting.
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  • 文章类型: Journal Article
    脉管系统网络向发育中的皮肤中的羽毛芽供应血液。早期皮肤发育过程中的脉管网络是通过从中央脉管系统顺序发芽而形成的,还是首先发生局部血管发生,然后与中央血管树相连?使用转基因日本鹌鹑Tg(TIE1p。H2B-eYFP),我们观察到羽毛原基形成后血管祖细胞出现。然后,脉管系统从每个芽中辐射出来,并与相邻芽的原始血管相连。后来它们与中央脉管系统相连。上皮-间质重组显示局部血管由上皮形成,其表达FGF2和VEGF。干扰noggin表达导致异常血管化。为了研究内皮起源,我们比较了TIE1p的转录组。从皮肤和主动脉收集的H2B-eYFP+细胞。来自皮肤的内皮细胞比来自主动脉的内皮细胞更接近于皮肤真皮细胞。结果表明,发育中的鸡皮脉管系统是通过(1)来自外周组织的生理性血管生成来组装的,和(2)随后与中央脉管系统连接。这项工作表明间充质可塑性和趋同分化在发育中起着重要作用,并且这些过程可以在成人再生期间重新激活。总结声明:我们展示了鸡皮中的脉管系统网络是使用现有的羽毛芽作为模板组装的,和内皮来自局部芽真皮和中央脉管系统。
    A vasculature network supplies blood to feather buds in the developing skin. Does the vasculature network during early skin development form by sequential sprouting from the central vasculature or does local vasculogenesis occur first that then connect with the central vascular tree? Using transgenic Japanese quail Tg(TIE1p.H2B-eYFP), we observe that vascular progenitor cells appear after feather primordia formation. The vasculature then radiates out from each bud and connects with primordial vessels from neighboring buds. Later they connect with the central vasculature. Epithelial-mesenchymal recombination shows local vasculature is patterned by the epithelium, which expresses FGF2 and VEGF. Perturbing noggin expression leads to abnormal vascularization. To study endothelial origin, we compare transcriptomes of TIE1p.H2B-eYFP+ cells collected from the skin and aorta. Endothelial cells from the skin more closely resemble skin dermal cells than those from the aorta. The results show developing chicken skin vasculature is assembled by (1) physiological vasculogenesis from the peripheral tissue, and (2) subsequently connects with the central vasculature. The work implies mesenchymal plasticity and convergent differentiation play significant roles in development, and such processes may be re-activated during adult regeneration. SUMMARY STATEMENT: We show the vasculature network in the chicken skin is assembled using existing feather buds as the template, and endothelia are derived from local bud dermis and central vasculature.
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  • 文章类型: Journal Article
    本文研究了改良的Hindmarsh-Rose(HR)模型的哈密顿能量,以观察其对短期记忆的影响。根据Helmholtz定理,在具有单个节点的简化系统中给出了哈密顿能量函数及其变量函数。我们考虑了耦合强度和神经元之间的联系在模式形成中的作用,以表明当所有神经元同步时,耦合和协作神经元对于产生火或清晰的短期记忆是必要的。然后,我们考虑了其他神经元的程度和外部刺激对短期记忆的出现和消失的影响,这表明产生短期记忆需要大量的能量,耦合强度可以进一步降低能耗。最后,总结了短期记忆产生的动力学机制。
    This paper investigates the Hamiltonian energy of a modified Hindmarsh-Rose (HR) model to observe its effect on short-term memory. A Hamiltonian energy function and its variable function are given in the reduced system with a single node according to Helmholtz\'s theorem. We consider the role of the coupling strength and the links between neurons in the pattern formation to show that the coupling and cooperative neurons are necessary for generating the fire or a clear short-term memory when all the neurons are in sync. Then, we consider the effect of the degree and external stimulus from other neurons on the emergence and disappearance of short-term memory, which illustrates that generating short-term memory requires much energy, and the coupling strength could further reduce energy consumption. Finally, the dynamical mechanisms of the generation of short-term memory are concluded.
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  • 文章类型: Journal Article
    复叶发育的里程碑是早期分离小叶原基的产生,其中涉及两个链接但不同的形态发生事件:小叶起始和小叶分离的边界建立。尽管在理解每个事件的调控途径方面取得了一些进展,目前还不清楚它们是如何内在协调的。这里,我们鉴定了PINNATE样PENTAFOLIATA2(PINNA2)基因,该基因编码了一种新鉴定的苜蓿中的GRAS转录因子。PINNA2转录物优先在器官边界检测。它的功能丧失突变将三叶叶转化为羽状五叶形态。PINNA2直接结合LEAFY直向同源单LEAFLET1(SGL1)的启动子区域,编码小叶启动的关键正调节因子,并下调其表达。进一步的分析显示,PINNA2与SGL1表达的其他两种抑制因子协同作用,BEL1样同源结构域蛋白PINNA1和C2H2锌指蛋白棕榈样PENTAFOLIATA1(PALM1),为了精确定义SGL1在复叶原基中的时空表达,从而保持小叶起始的适当模式。此外,我们表明,富集表达的PINNA2在小叶到小叶的边界是由边界特异性基因MtNAM正调控,这对于小叶边界的形成至关重要。一起,这些结果揭示了边界表达转录因子PINNA2在调节小叶起始中的关键作用,为复杂的发育过程的协调提供分子见解。
    The milestone of compound leaf development is the generation of separate leaflet primordia during the early stages, which involves two linked but distinct morphogenetic events: leaflet initiation and boundary establishment for leaflet separation. Although some progress in understanding the regulatory pathways for each event have been made, it is unclear how they are intrinsically coordinated. Here, we identify the PINNATE-LIKE PENTAFOLIATA2 (PINNA2) gene encoding a newly identified GRAS transcription factor in Medicago truncatula. PINNA2 transcripts are preferentially detected at organ boundaries. Its loss-of-function mutations convert trifoliate leaves into a pinnate pentafoliate pattern. PINNA2 directly binds to the promoter region of the LEAFY orthologue SINGLE LEAFLET1 (SGL1), which encodes a key positive regulator of leaflet initiation, and downregulates its expression. Further analysis revealed that PINNA2 synergizes with two other repressors of SGL1 expression, the BEL1-like homeodomain protein PINNA1 and the C2H2 zinc finger protein PALMATE-LIKE PENTAFOLIATA1 (PALM1), to precisely define the spatiotemporal expression of SGL1 in compound leaf primordia, thereby maintaining a proper pattern of leaflet initiation. Moreover, we showed that the enriched expression of PINNA2 at the leaflet-to-leaflet boundaries is positively regulated by the boundary-specific gene MtNAM, which is essential for leaflet boundary formation. Together, these results unveil a pivotal role of the boundary-expressed transcription factor PINNA2 in regulating leaflet initiation, providing molecular insights into the coordination of intricate developmental processes underlying compound leaf pattern formation.
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  • 文章类型: Journal Article
    一些多细胞生物中细胞分化的空间周期信号是根据图灵模式形成原理产生的。用丝状蓝细菌Nostocsp解决了分裂细胞如何响应分化信号。PCC7120,形成杂环的图案化分布。我们表明,分裂细胞的分化被延迟,直到其分裂完成,只有一个子细胞成为异形细胞。patU3的突变体,它编码异形形成的抑制剂,没有显示出这种延迟,并且从细胞分裂的子细胞中形成了异形对,或者从进行胞质分裂的细胞中形成了哑铃形异形。patA突变体,仅在细丝末端形成杂环,patU3的单核苷酸突变恢复了cal间杂环,patU3/patA和patU3/hetF的双突变体具有patU3突变体的表型。我们提供的证据表明HetF,可以降解PatU3的细胞通过其C末端结构域被募集到细胞分裂体。具有N末端肽酶结构域但缺乏C末端结构域的HetF突变体不能阻止杂环对的形成,这表明需要HetF的分裂体募集来隔离HetF,以延迟分裂细胞的分化。我们的研究表明,PatU3在分化的细胞分裂耦合控制中起着关键作用。
    Spatial periodic signal for cell differentiation in some multicellular organisms is generated according to Turing\'s principle for pattern formation. How a dividing cell responds to the signal of differentiation is addressed with the filamentous cyanobacterium Nostoc sp. PCC 7120, which forms the patterned distribution of heterocysts. We show that differentiation of a dividing cell was delayed until its division was completed and only one daughter cell became heterocyst. A mutant of patU3, which encodes an inhibitor of heterocyst formation, showed no such delay and formed heterocyst pairs from the daughter cells of cell division or dumbbell-shaped heterocysts from the cells undergoing cytokinesis. The patA mutant, which forms heterocysts only at the filament ends, restored intercalary heterocysts by a single nucleotide mutation of patU3, and double mutants of patU3/patA and patU3/hetF had the phenotypes of the patU3 mutant. We provide evidence that HetF, which can degrade PatU3, is recruited to cell divisome through its C-terminal domain. A HetF mutant with its N-terminal peptidase domain but lacking the C-terminal domain could not prevent the formation of heterocyst pairs, suggesting that the divisome recruitment of HetF is needed to sequester HetF for the delay of differentiation in dividing cells. Our study demonstrates that PatU3 plays a key role in cell-division coupled control of differentiation.
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  • 文章类型: Journal Article
    活性材料与几何约束边界之间的相互作用是活性系统中许多新兴现象的关键。对于由动物细胞或活动细菌组成的活性物质,限制边界通常是一个可变形的界面,目前尚不清楚活动诱导的界面动力学如何导致形态发生和模式形成。这里,我们研究了受可变形边界限制的细菌活性物质的进化。我们发现,在界面处出现了有序的形态图案,其特征是周期性间隔开的界面突起;在界面突起之后,细菌游泳者自组织成多细胞簇,显示1/2向列缺陷。随后,从界面突起到爬行分支的分层过渡序列使细菌活性液滴以惊人的自相似分支模式快速侵入周围空间。我们发现这种界面图案在几何上受到界面局部曲率的控制,我们表示为集体曲率感应的现象。使用连续活动模型,我们发现,集体曲率传感是由高曲率区域附近增强的主动应力引起的,有效长度标度设置界面突起之间的特征距离。我们的发现揭示了从突起到分支的过渡是活性物质入侵的独特模式,并提出了一种设计活性物质模式形成的策略。
    Interaction between active materials and the boundaries of geometrical confinement is key to many emergent phenomena in active systems. For living active matter consisting of animal cells or motile bacteria, the confinement boundary is often a deformable interface, and it has been unclear how activity-induced interface dynamics might lead to morphogenesis and pattern formation. Here, we studied the evolution of bacterial active matter confined by a deformable boundary. We found that an ordered morphological pattern emerged at the interface characterized by periodically spaced interfacial protrusions; behind the interfacial protrusions, bacterial swimmers self-organized into multicellular clusters displaying +1/2 nematic defects. Subsequently, a hierarchical sequence of transitions from interfacial protrusions to creeping branches allowed the bacterial active drop to rapidly invade surrounding space with a striking self-similar branch pattern. We found that this interface patterning is geometrically controlled by the local curvature of the interface, a phenomenon we denote as collective curvature sensing. Using a continuum active model, we revealed that the collective curvature sensing arises from enhanced active stresses near high-curvature regions, with the active length scale setting the characteristic distance between the interfacial protrusions. Our findings reveal a protrusion-to-branch transition as a unique mode of active matter invasion and suggest a strategy to engineer pattern formation of active materials.
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  • 文章类型: Journal Article
    在干旱或半干旱的环境中,降水对植被生长起着至关重要的作用。最近的研究表明,植被生长对降水的响应具有滞后效应。为了探索滞后现象背后的机制,我们提出并研究了具有时空非局部效应的水植被模型。结果表明,时间核函数不影响图灵分叉。为了更好地理解滞后效应和非本地竞争对植被格局形成的影响,我们选择了一些特殊的核函数,并获得了一些有见地的结果:(i)时间延迟不会触发植被格局的形成,但是可以推迟植被的进化。此外,在没有扩散的情况下,时间延迟会导致稳定性开关的发生,而在扩散的存在下,可能会出现空间非均匀时间周期解,但没有稳定性开关;(Ii)空间非局部相互作用可能触发水和植被小扩散率的模式开始,并且可以改变孤立植被斑块的数量和大小,以获得较大的扩散率。(iii)时间延迟和空间非局部竞争之间的相互作用可能会导致行波模式的出现,所以植被在太空中保持周期性,而是在时间上振荡。这些结果表明,降水可以显着影响植被的生长和空间分布。
    In an arid or semi-arid environment, precipitation plays a vital role in vegetation growth. Recent researches reveal that the response of vegetation growth to precipitation has a lag effect. To explore the mechanism behind the lag phenomenon, we propose and investigate a water-vegetation model with spatiotemporal nonlocal effects. It is shown that the temporal kernel function does not affect Turing bifurcation. For better understanding the influences of lag effect and nonlocal competition on the vegetation pattern formation, we choose some special kernel functions and obtain some insightful results: (i) Time delay does not trigger the vegetation pattern formation, but can postpone the evolution of vegetation. In addition, in the absence of diffusion, time delay can induce the occurrence of stability switches, while in the presence of diffusion, spatially nonhomogeneous time-periodic solutions may emerge, but there are no stability switches; (ii) The spatial nonlocal interaction may trigger the pattern onset for small diffusion ratio of water and vegetation, and can change the number and size of isolated vegetation patches for large diffusion ratio. (iii) The interaction between time delay and spatial nonlocal competition may induce the emergence of traveling wave patterns, so that the vegetation remains periodic in space, but is oscillating in time. These results demonstrate that precipitation can significantly affect the growth and spatial distribution of vegetation.
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  • 文章类型: Journal Article
    在通信受限的水下环境下,具有机载摄像机的多小型AUV系统的编队建设至关重要。为了快速收敛到领导者-追随者模式,提出了一种混合协调策略。该策略包括两部分:基于时间最优局部位置的控制器(TOLC)和分布式异步离散加权一致性控制器(ADWCC)。TOLC控制器旨在优化给定模式中AUV目的地的分配,并以最短的可行距离将每个AUV引导至其目的地。ADWCC控制器的开发是为了引导被障碍物阻挡的AUV到达目的地,并利用车载摄像机感知到的邻居的信息。从理论上讨论了所提出策略的快速性。在MATLAB和Blender的仿真环境中验证了该算法的有效性。
    Formation building for multi-small-AUV systems with on-board cameras is crucial under the limited communication underwater environment. A hybrid coordination strategy is proposed for the rapid convergence to a leader-follower pattern. The strategy consists of two parts: a time-optimal local-position-based controller (TOLC) and a distributed asynchronous discrete weighted consensus controller (ADWCC). The TOLC controller is designed to optimize the assignation of AUVs\' destinations in the given pattern and guide each AUV to its destination by the shortest feasible distance. The ADWCC controller is developed to direct the AUVs blocked by obstacles to reach their destinations with the information from the perceived neighbors by on-board cameras. The rapidity of the proposed strategy is theoretically discussed. The effectiveness of the proposed algorithm has been verified in the simulation environments in both MATLAB and Blender.
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  • 文章类型: Journal Article
    声誉和互惠是人类社会合作的关键机制,经常携手支持亲社会行为而不是自私行为。在这里,我们回顾了探索这两种机制的物理学和进化博弈论界面的最新研究。我们专注于形象评分作为声誉的承担者,以及各种类型的互惠,包括直接,间接,和网络互惠。我们回顾了声誉和互惠动态的不同定义,我们展示了这些如何影响社会困境中合作的演变。我们考虑一阶,二阶,以及混合和结构化人群中的高阶模型,我们回顾了支持和告知数学建模和模拟结果的实验工作。我们还提供了综述的研究以及六个方向的展望,这些方向似乎特别有希望在未来探索。
    Reputation and reciprocity are key mechanisms for cooperation in human societies, often going hand in hand to favor prosocial behavior over selfish actions. Here we review recent researches at the interface of physics and evolutionary game theory that explored these two mechanisms. We focus on image scoring as the bearer of reputation, as well as on various types of reciprocity, including direct, indirect, and network reciprocity. We review different definitions of reputation and reciprocity dynamics, and we show how these affect the evolution of cooperation in social dilemmas. We consider first-order, second-order, as well as higher-order models in well-mixed and structured populations, and we review experimental works that support and inform the results of mathematical modeling and simulations. We also provide a synthesis of the reviewed researches along with an outlook in terms of six directions that seem particularly promising to explore in the future.
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