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Climatic niche divergence and long-distance dispersal contributed to the pantropical intercontinental disjunctions of a liana lineage(Uncaria,Rubiaceae)
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作者 Xian-Han Huang Jing-Yi Peng +11 位作者 Nan Lin Jian Liu Jun-Tong Chen Qun Liu Xin-Jian Zhang Quan-Sheng Fu Peng-Rui Luo Zhi-Yu Wang Shiou Yih Lee Qiang Zhou Hang Sun Tao Deng 《Plant Diversity》 2025年第5期772-783,共12页
The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined ... The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined in herbs,shrubs,and trees,and less commonly studied in interlayer plant taxa.Here we examined evolutionary processes that resulted in the PID of a pantropical woody liana,Uncaria(Rubiaceae).We first constructed a comprehensive phylogeny by employing 73 plastid protein-coding sequences from 29 accessions of Uncaria(including 16 newly sequenced)from different continents.We then inferred divergence time,history and ecological niche evolution of this genus.Our results showed that Uncaria consisted of four well-supported clades that belonged to two geographically distinct lineages:the Asia-Oceania lineage and the Afro-Neotropical lineage.Biogeographic reconstruction showed this genus likely originated in Asia during the early Miocene(ca.19.03 Ma)and the Middle Miocene Climatic Optimum may have triggered the early diversification of Uncaria.Due to its recent origin and small seeds with long wings,wind or water-mediated long-distance dispersal may have contributed to the distribution of Uncaria in tropical Oceania(via stepping-stone dispersal)and tropical Africa and America(by transoceanic dispersal).Our findings also indicate that diversification of Uncaria was primarily driven by ecological niche divergence,particularly climatic factors.Our study emphasizes the dual role of climatic niche divergence and long-distance dispersal in shaping the PID of Uncaria,providing references for many other extant lineages with similar distributions. 展开更多
关键词 Niche evolution Long-distance dispersal Pantropical intercontinental disjunction Miocene Woody lianas Uncaria
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Evolution of the Madrean-Tethyan disjunctions and the North and South American amphitropical disjunctions in plants 被引量:14
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作者 Jun WEN Stefanie M. ICKERT-BOND 《Journal of Systematics and Evolution》 SCIE CSCD 北大核心 2009年第5期331-348,共18页
The present paper reviews advances in the study of two major intercontinental disjunct biogeographic patterns: (i) between Eurasian and western North American deserts with the Mediterranean climate (the Madrean- T... The present paper reviews advances in the study of two major intercontinental disjunct biogeographic patterns: (i) between Eurasian and western North American deserts with the Mediterranean climate (the Madrean- Tethyan disjunctions); and (ii) between the temperate regions of North and South America (the amphitropical disjunctions). Both disjunct patterns have multiple times of origin. The amphitropical disjunctions have largely resulted from long-distance dispersal, primarily from the Miocene to the Holocene, with available data indicating that most lineages dispersed from North to South America. Results of recent studies on the Mediterranean disjuncts between the deserts of Eurasia and western North America support the multiple modes of origin and are mostly consistent with hypotheses of long-distance dispersal and the North Atlantic migration. Axelrod's Madrean-Tethyan hypothesis, which implies vicariance between the two regions in the early Tertiary, has been favored by a few studies. The Beringian migration corridor for semiarid taxa is also supported in some cases. 展开更多
关键词 amphitropical disjunctions BIOGEOGRAPHY Madrean-Tethyan disjunctions Mediterranean disjuncts North-South American disjunctions.
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Phylogenetic analysis of Toxicodendron(Anacardiaceae) and its biogeographic implications on the evolution of north temperate and tropical intercontinental disjunctions 被引量:6
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作者 Ze-Long NIE Hang SUN +1 位作者 Ying MENG Jun WEN 《Journal of Systematics and Evolution》 SCIE CSCD 北大核心 2009年第5期416-430,共15页
Toxicodendron is a genus in the Rhus complex of Anacardiaceae with a disjunct distribution between eastern Asia and North America, extending to southeastern Asia and the neotropics. Nuclear (internal transcribed spac... Toxicodendron is a genus in the Rhus complex of Anacardiaceae with a disjunct distribution between eastern Asia and North America, extending to southeastern Asia and the neotropics. Nuclear (internal transcribed spacer, external transcribed spacer, and NIA-i3) and chloroplast (ndhF and trnL-F) sequences were used to construct phylogenetic relationships of Toxicodendron. Phylogenetic analysis of these data strongly support Toxieodendron as a monophyletic group distinct from other genera of the Rhus complex, and the phylogeny does not fully corroborate classification at the sectional level. Two temperate disjunct lineages were detected, one from section Toxicodendron and the other between the eastern North American Toxicodendron vernix and the eastern Asian Toxicodendron vernieifluum. Their divergence times were estimated to be 13.46 (7.95-19.42) and 7.53 (2.76-12.86) mya, respectively. The disjunction between section Griffithii (taxa from warm temperate to tropical Asia) and Toxieodendron striatum (from the neotropics) was supported and their divergence time was estimated to be 20.84 (11.1 6-30.52) mya in the early Miocene. Our biogeographic results and the paleontological data support the Bering land bridge as the most likely route to explain the temperate disjunctions, yet the tropical disjunction in Toxicodendron seems to be best explained by the North Atlantic land bridge hypothesis. 展开更多
关键词 ANACARDIACEAE biogeography DISJUNCTION eastern Asia NEOTROPICS North America PHYLOGENETICS Toxicodendron.
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自然口语对话中的“还是” 被引量:2
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作者 方梅 《汉语学报》 北大核心 2025年第1期2-14,共13页
自然口语对话中,由“还是”构成的选择问句有多种形式,由“还是”系连的并列项不仅在结构上会呈现出不对称性,其功能也呈现出多样性。虽然“或者”与“还是”在书面语中的差异或许体现为“标准析取并列”与“疑问析取并列”的对立,但是... 自然口语对话中,由“还是”构成的选择问句有多种形式,由“还是”系连的并列项不仅在结构上会呈现出不对称性,其功能也呈现出多样性。虽然“或者”与“还是”在书面语中的差异或许体现为“标准析取并列”与“疑问析取并列”的对立,但是在自然口语对话中,用于追加信息时,这种对立有可能被中和;而出现于回应话轮之首的“或者”,用于提出建议,即便采用疑问句法,也不能被“还是”替换。当“还是”位于话轮末形成不完整话轮或单独用作一个话轮时,原有的句法功能弱化、语义被漂白,仅体现言者的互动意图。它作为特定互动行为的载体,具有位置敏感性。“疑问析取并列”不能完全概括“还是”的用法,但能为理解“还是”的功能扩展路径提供可能的解释。 展开更多
关键词 自然口语对话 “还是” “或者” 疑问析取并列 互动行为
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观察性研究中的因果图和混杂因素的识别和选择准则
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作者 刘慧珍 周小芹 +1 位作者 王婷 康德英 《药物流行病学杂志》 2025年第10期1206-1212,共7页
在观察性研究中,准确可靠地估计暴露对结局的因果效应是其核心目标,而确定并充分矫正混杂因素是实现这一目标的关键前提和核心挑战。混杂因素控制不当——无论是遗漏关键混杂(导致残余混杂),还是过度调整无关变量(引入碰撞偏倚等)——... 在观察性研究中,准确可靠地估计暴露对结局的因果效应是其核心目标,而确定并充分矫正混杂因素是实现这一目标的关键前提和核心挑战。混杂因素控制不当——无论是遗漏关键混杂(导致残余混杂),还是过度调整无关变量(引入碰撞偏倚等)——都会直接扭曲效应估计结果,进而可能产生误导性的科学结论和临床决策。因此,开发并应用系统、透明且可重复的混杂因素识别与选择策略,对提升观察性研究因果推断的效度与可靠性具有根本性意义。本文通过系统综述有向无环图(DAGs)这一强大的可视化因果建模工具,并深入评析3种基于DAGs的主流混杂因素选择准则(Pre-exposure准则、Common cause准则、Modified disjunctive cause准则),为研究者提供一个结构化、理论依据充分的混杂因素识别与选择框架,以期显著优化观察性研究中因果效应的估计过程。 展开更多
关键词 混杂因素 混杂 有向无环图 Pre-exposure准则 Common cause准则 Modified disjunctive cause准则
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改进PPO算法求解柔性作业车间调度问题 被引量:2
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作者 吴昊泽 李艳武 谢辉 《计算机集成制造系统》 北大核心 2025年第8期2894-2904,共11页
柔性作业车间需要提高调度效率,缩短生产周期。为此以最小化最大完工时间为目标,采用机器选择和工件工序调整两种调度策略,建立混合整数规划模型,并提出了一种基于策略和图神经网络的深度强化学习算法来求解。该算法利用图神经网络获取... 柔性作业车间需要提高调度效率,缩短生产周期。为此以最小化最大完工时间为目标,采用机器选择和工件工序调整两种调度策略,建立混合整数规划模型,并提出了一种基于策略和图神经网络的深度强化学习算法来求解。该算法利用图神经网络获取和分析析取图的信息,为强化学习提供决策依据;提出了使用多近端策略优化和多指针图网络学习作业操作动作策略和机器动作策略,设计两个编码器-解码器定义两个动作策略,并将图神经网络嵌入到局部状态,增强局部搜索能力。实验结果表明所提出的算法在求解性能和泛化能力方面显著优于对比算法。 展开更多
关键词 深度强化学习 柔性作业车间调度问题 析取图 图神经网络 多近端策略优化算法
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十大功劳属(小檗科)叶结构分型新体系
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作者 赵白龙 李业亮 +1 位作者 王宇飞 孙斌 《植物学报》 北大核心 2025年第4期562-572,共11页
小檗科十大功劳属(Mahonia)是典型的东亚–北美洲际间断分布属,在北半球新生代地层中有丰富的叶化石记录。其叶结构特征特殊,易与其它被子植物类群区分,有潜力成为一个独特的生物代用指标或模式植物,用于追踪东亚–北美物种间断分布格... 小檗科十大功劳属(Mahonia)是典型的东亚–北美洲际间断分布属,在北半球新生代地层中有丰富的叶化石记录。其叶结构特征特殊,易与其它被子植物类群区分,有潜力成为一个独特的生物代用指标或模式植物,用于追踪东亚–北美物种间断分布格局形成过程。传统分类依据叶结构特征将十大功劳属分为掌状脉的东方组和羽状脉的西方组。在前人研究的基础上,依据详细的叶结构特征将该属进一步细分为东方组的7个叶片类型(Microphylla类型、Japonica类型、Cardiophylla类型、Bodinieri类型、Polyodonta类型、Fortunei类型和Nervosa类型)和西方组的6个叶片类型(Chochoco类型、Dictyota类型、Volcania类型、Pumila类型、Lanceolata类型和Aquifolium类型)。新建的十大功劳属叶结构分型体系将有极大潜力服务于该属化石叶的分型及追踪其叶形态演化和洲际间断分布式样的形成。 展开更多
关键词 十大功劳属 叶结构 分型 形态演化 东亚–北美间断分布
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基于深度强化学习算法的协同制造调度优化 被引量:1
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作者 唐亮 匡理霖 《计算机集成制造系统》 北大核心 2025年第8期2857-2869,共13页
针对主导制造商将多个流程外包给协同制造商的协同调度问题,考虑同类产品不同订单在协同制造网络中的分配与调度,以多种成本之和的最小化为目标,提出了一种结合析取图的深度强化学习算法框架。根据输入的订单状态学习动作策略,将析取图... 针对主导制造商将多个流程外包给协同制造商的协同调度问题,考虑同类产品不同订单在协同制造网络中的分配与调度,以多种成本之和的最小化为目标,提出了一种结合析取图的深度强化学习算法框架。根据输入的订单状态学习动作策略,将析取图的调度过程转化为一个多阶段的序列决策过程;利用基于析取图的状态空间,将协同制造订单的状态视为多通道图像输入网络,并依据状态转移的特点设计了包含订单选择规则和协同制造商指派规则的二维动作空间。根据问题的目标构造了关于成本的奖励函数,以指导智能体与环境交互,获取每个决策步最佳策略。实验结果表明,深度强化学习算法优于单一调度规则,与遗传算法相比较,在平均求解效果上表现更为优越。 展开更多
关键词 协同制造 析取图 深度强化学习 调度 马尔可夫决策过程
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Peak-heat-flux entry test trajectory optimization by disjunctive programming
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作者 Zexiao DENG Luhua LIU 《Chinese Journal of Aeronautics》 2025年第11期207-227,共21页
To evaluate the heat performance of the lifting-body entry vehicle during the hypersonic gliding phase,entry flight heat tests involving the determination of the maximum peak-heat-flux entry trajectory with complex co... To evaluate the heat performance of the lifting-body entry vehicle during the hypersonic gliding phase,entry flight heat tests involving the determination of the maximum peak-heat-flux entry trajectory with complex constraints are essential.A significant obstacle is the uncertainty of passage time or energy states of the maximum peak entry heat flux point and waypoints.This paper showcases an endeavour to leverage disjunctive programming and combinatorial theory for the max-max type(maximum peak-heat-flux)Entry Trajectory Optimization(ETO)problems with complex constraints such as dynamic pressure,normal load,waypoints,and no-fly zones.The concept of a"generalized waypoint"is introduced,and the maximum peak-heat-flux point is regarded as a"generalized waypoint".Through the application of propositional calculus rules,the derivation of generalized waypoints incorporating various physical quantities and magnitudes such as heat flux density,longitude,and latitude is actualized in one disjunctive normal form,enabling resolution via a unified method.Consequently,a novel method based on combinatorial prior rules is proposed,utilizing Successive Mixed-Integer Nonlinear Programming(SMINLP)to optimize various heat entry test flight trajectories.Numerical experiments are provided to show the computational accuracy,stability,and adaptability of the proposed method in solving maxmax type entry optimal control problems. 展开更多
关键词 Disjunctive programming Entry trajectory optimization Max-max type cost function Peak-heat-flux test trajectory Waypoint constraints
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