Quantifying source-sink relationships in leaf-color modified rice genotypes during grain filling

Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.

The Strange Relationship between the Momentum of a Photon Emitted from an Electron and the Momentum Acquired by the Electron

In quantum mechanics, the energy of a hydrogen atom is minimized when the principal quantum number n is 1. However, the author has previously pointed out that the hydrogen atom has a state where n=0. An electron in the state where n=0has zero rest mass energy. However, a hydrogen atom has an energy level even lower than the n=0state. This is hard to accept from the standpoint of common sense. Thus, the author has previously pointed out that an electron at the energy level where n=0has zero energy because the positive energy mec2and negative energy −mec2cancel each other out. This paper elucidates the strange relationship between the momentum of a photon emitted when a hydrogen atom is formed by an electron with such characteristics, and the momentum acquired by the electron.

基于改进APF-QRRT^(*)策略的移动机器人路径规划

针对Q-RRT^(*)算法在路径规划过程中无法兼顾可达性和安全性的问题,提出一种改进APF-QRRT^(*)(IAPF-QRRT^(*))路径规划策略。IAPF-QRRT^(*)策略通过Q-RRT^(*)算法获得一组连接起点到终点的离散关键路径点,较传统的快速搜索随机树(RRT^(*))算法具备更好的初始解和更快的收敛速度。改进传统人工势场(APF)方法获得一种新的无势正交向量场,在一定条件下使整体排斥向量场与吸引向量场正交,并将其作用于关键路径点,从而提高路径的安全性。将IAPF-QRRT^(*)策略与其他算法比较,通过数值模拟实验证明了所提策略的有效性。

加强型Q460C方钢管间隙N型节点承载力研究

为考察加强构造对N型节点失效机理和承载力的影响规律,对加强节点和基本节点进行了主管轴压静力加载试验,试验结果表明:基本节点的破坏模式为主管上翼缘受拉鼓曲开裂,加强节点破坏模式为加劲板屈曲和覆板焊缝受拉开裂;加强节点的承载力较基本节点提高了9.4%~36.5%;增加覆板厚度,可明显提高节点承载力。采用ABAQUS软件对覆板和加劲板加强的Q460C方钢管间隙N型节点进行了有限元参数研究,考察了主管宽厚比γ、主支管厚度比η、主支管宽度比β、受拉支管与主管夹角θ、支管间距与主管宽度比ξ对节点破坏模式、应力分布、主管荷载-位移曲线和覆板焊缝断裂指数I f的影响规律。根据试验和数值模拟结果,提出了覆板和加劲板加强的Q460C方钢管间隙N型节点承载力计算式和构造设计建议。

Relationship between the use of smart medical services and mental health status

In this editorial,I comment on the article by Zhang et al.To emphasize the importance of the topic,I discuss the relationship between the use of smart medical devices and mental health.Smart medical services have the potential to positively influence mental health by providing monitoring,insights,and inter-ventions.However,they also come with challenges that need to be addressed.Understanding the primary purpose for which individuals use these smart tech-nologies is essential to tailoring them to specific mental health needs and prefe-rences.

Q550E高强钢及焊接接头的疲劳裂纹扩展研究

焊接构造是钢桥的薄弱部位,在反复车辆荷载作用下,疲劳损伤正逐步成为影响桥梁服役安全的关键问题之一。以Q550E高强钢为研究对象,开展母材和对接焊缝接头的静力拉伸和疲劳裂纹扩展试验,建立母材及焊接连接件的疲劳裂纹增长模型,揭示了应力比对高强钢焊接节点疲劳裂纹扩展速率的影响规律;开展基于FRANC3D和ABAQUS的联合仿真模拟分析,通过敏感性分析明确关键影响参数。结果表明:随着应力比的增大,疲劳裂纹扩展速率参数m增大、lg C减小,应力强度因子门槛值减小;对接焊缝m值约为母材的2倍,对接焊缝裂纹门槛值大于母材,且对应力比更敏感;联合仿真方法可准确预测高强钢焊接接头疲劳寿命,高应力比下试件厚度和初始裂纹深度对疲劳扩展影响显著。

基于UPLC-Q-TOF/MS^(E)结合UNIFI质谱数据平台快速表征鉴定天南星中的化学成分

目的:建立天南星中化学成分快速表征的分析方法,并用于该药材的质量控制。方法:采用超高效液相色谱联用四级杆串联飞行时间质谱(UPLC-Q-TOF/MS)结合UNIFI质谱数据分析平台,选择Waters Acquity UPLC HSS T 3 C 18色谱柱,以0.1%甲酸水和0.1%甲酸乙腈为流动相进行梯度洗脱,流速为0.35 mL/min,进样量5μL;选择电喷雾离子源,以MS^(E)模式采集正、负离子下天南星化学成分的质谱数据;通过UNIFI平台自带数据库结合文献检索建立天南星化学成分数据库,并根据化合物的精准分子质量、二级碎片离子信息及与对照品和文献数据等比对进化学成分的鉴定。结果:在正离子模式下鉴定出49个化合物,负离子模式下鉴定16个化合物,主要以有机酸、氨基酸及黄酮苷类化合物为主。其中,35个化合物可能首次从天南星中发现。结论:采用UPLC-Q-TOF/MS结合UNIFI平台的分析方法可快速鉴定天南星的化学成分,该研究结果可为天南星药效物质基础的研究以及质量控制体系建立和产品开发等提供科学依据。

Phylogenetic Relationships and Status Quo of Colonies for Gayal Based on Analysis of Cytochrome b Gene Partial Sequences

Thirty-three mutations and four different haplotypes were found when cytochrome b（Cytb） gene partial sequences of 12 gayals were analyzed. Together with sequences of Bos indicus, Bos taurus, Bos grunniens, and Bos gaurus with Bubalus bubalis as the out group, the partial sequences of Cytb gene of gayals were aligned and base composition and nucleotide variation of Cytb gene were analyzed. The phylogenetic trees were constructed by the NJ method and the MP method respectively, both supporting almost the same topology. Gayal is an independent species of Bos from Bos indicus, Bos taurus, and Bos gaurus. The results also indicate that a great proportion of gayal bloodline was invaded by other species, and the protection of gayal is facing a formidable situation.

Infrageneric and Sectional Relationships in the Genus Rhododendron (Ericaceae) Inferred from ITS Sequence Data

The internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (including 5.8S rRNA) of 15 Rhododendron, species, representing most sections of the genus, one Ledum species and Cassiope fastigiata were sequenced. Together with the ITS sequences of 13 selected Rhododendron species and Bejaria racemosa downloaded from GenBank, we explored the infrageneric and sectional relationships of this important North Temperate genus by employing maximum-parsimony analysis using PAUP software. C. fastigiata and B. racemosa were designated as outgroups. The ITS-based tree inferred that: (1) Rhododendron was a well-supported monophyletic group, while subg. Therorhodion was basal to the rest of the genus; (2) Ledum was a member of Rhododendron, and its close relationship with the lepidote rhododendron was confirmed; (3) the lepidote rhododendron plus Ledum formed a strongly-supported monophyletic clade which was sister to the rest of the elepidote rhododendron; (4) the elepidote rhododendron formed a weakly-supported clade within which the monophyly of subg. Hynwrianthes and subg. Tsutsusi were strongly supported, while subg. Pentanthera and subg. Azaleastrum were polyphyletic; and (5) the monophyly of sect. Choniastnini, (subg. Azaleastrum) was strongly-supported, while subg. Tsutsusi could be sister to a weakly-supported clade composed of two sampled species of sect. Azaleastrum (subg. Azaleastrum) together with R. sentibarbatum, of subg. Mumeazalea.

The Phylogenetic Relationships among Four Subspecies of the Genus Locusta Based on Sequences of Three Subunit of Cytochrome Oxidase

[Objective] The aim was to explore the phylogenetic relationships among four subspecies of the genus Locusta.[Method] The sequences of three subunits of cytochrome oxidase of Locusta migratoria tibetensis and Locusta migratoria manilensis were amplified and sequenced（COⅠ 1 539 bp,COⅡ 684 bp,CO Ⅲ 792 bp,with the total of 3 015 bp）.The corresponding sequenses of Locusta migratoria migratoria and Locusta migratoria migratorioides were obtained from GenBank and constructed a multiple alignment.Phylogenic trees of four subspecies of L.migratoria were constructed by Neighbor-Joining,Maximum-parsimony and Bayesian,respectively.[Result] The average content of A ＋ T in three subunits of four subspecies was 69.57%;the third site of codon showed the highest A ＋ T content,and the COⅠ had the highest A ＋ T content（87.6%）;The nucleotide substitution mainly occurred at the third site of codon,and the nucleotide replacement rate of CO Ⅱ was the highest.The second site of codon was conservative,so the replacement rate was in the range of 5.9%-15%.The start codon of COⅠ was CCG or ACG.Genetic distances among four subspecies were ranged from 0.001 to 0.076.The relationship between L.m.tibetensis and Locusta migratoria manilensis was the closest,followed by L.m.migratorioides and L.m.migratorioides,while the genetic distance between L.m.tibetensis and L.m.migratorioides was the largest.[Conclusion] The phylogenetic relationships among four subspecies of Locusta migratoria is L.m.tibetensis,L.m.manilensis,L.m.migratoria,L.m.migratorioides.

Application of PCA and HCA to the Structure-Activity Relationship Study of Fluoroquinolones

Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analysis （HCA） were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments.

Phylogenetic Relationships of Caragana(Fabaceae) by the Use of nrITS Sequences

[Objective] The aim was to explore the phylogenetic relationships of Cara- gana （Fabaceae） by the use of nrlTS sequences. [Method] Internal transcribed spac- er （ITS） sequences of nuclear ribosomal DNA （nrDNA） from 29 taxa of Caragana species and seven close relatives （all belong to Astralinae （Adens） Benth） were used for phylogenetic analysis. [Result] Length of the entire ITS region ranges from 611 to 614 bp in Caragana species. The aligned sequences nrlTS of Caragana are 655 bp, and 170 sites are variable, with 107 phylogenetically informative sites. The phylogenetically informative sites are 16.3% of the total aligned sequences. The ITS sequences data are useful to resolve some relationships at lower taxonomic levels within Caragana. The Caragana Fabr. is not a monophyletic group with very close connection with Calophaca tianschanica. The ITS data revealed that the species of Sect. tragacanthoides were dispersed in MP tree or ME tree. Although the morphol- ogy of C. ordosica is similar to C. tibetica, the ITS results revealed an unexpectedly close relativeship to C. roborovskyi. The ITS data also indicate C. davazamcii, C. korshinskii, C. intermedia, and C. microphylla are different species. [Conclusion] ITS sequences have an important reference value in exploring the relationships of Cara- gana.

Phylogenetic Relationship of an Extremely Endangered Species, Pinus squamata (Pinaceae) Inferred from Four Sequences of the Chloroplast Genome and ITS of the Nuclear Ribosomal DNA

Pinus squamata X. W. Li, a recently-described species of the Pinaceae, is an extremely endangered pine with only 32 individuals in the wild. This species was thought to be intermediate between P. bungeana Zuec. ex Endl. of subgen. Strobus and P. yunnanensis Franch. of subgen. Pinus by the original author. We made an effort to address the question of the phylogenetic relationship of this peculiar and important species in the context of the major groups of the genus Pinus by using sequences of the rbcL, matK,genes, rpl20-rps18 spacer, trnV intron of the chloroplast genome and the nuclear ribosomal ITS region. The results of the separated analysis and the combined analysis of the four cpDNA sequences and ITS sequence indicated that P. squamata was a stable member of subsect. Gerardianae and P. gerardiana Wall. was the closest species of P. squamata phylogenetically. As a result, the causes of the distribution pattern of subsect. Gerardianae were also discussed.

基于改进DQN算法的应召搜潜无人水面艇路径规划方法

针对应召反潜中无人水面艇航向和航速机动的情形,提出一种基于改进深度Q学习(Deep Q-learning,DQN)算法的无人艇路径规划方法。结合应召搜潜模型,引入改进的深度强化学习(Improved-DQN,I-DQN)算法,通过联合调整无人水面艇(Unmanned Surface Vessel,USV)的动作空间、动作选择策略和奖励等,获取一条最优路径。算法采用时变动态贪婪策略,根据环境和神经网络的学习效果自适应调整USV动作选择,提高全局搜索能力并避免陷入局部最优解;结合USV所处的障碍物环境和当前位置设置分段非线性奖惩函数,保证不避碰的同时提升算法收敛速度;增加贝塞尔算法对路径平滑处理。仿真结果表明,在相同环境下新方法规划效果优于DQN算法、A^(*)算法和人工势场算法,具有更好的稳定性、收敛性和安全性。

认知诊断评估中Q矩阵理论及应用

Q矩阵是认知心理学与心理计量学结合的重要载体,Q矩阵在认知诊断中发挥着十分重要的作用。Q矩阵理论和应用研究近年来取得了重要进展。众多研究者从结构化到非结构化、属性二值到多值、简单到复杂模型、独立到一般结构、0-1到多级评分方面不断深入和拓展Q矩阵理论。Q矩阵理论也广泛应用于测验构念效度评价、计算机化自适应测验选题策略设计、Q矩阵学习和标定、认知诊断测验组卷等。与模型无关的Q矩阵理论和适合特定认知诊断模型下Q矩阵理论,以及最新Q矩阵理论的应用都值得深入研究。

一种基于DQN的去中心化优先级卸载策略

边缘计算(EC)可在网络边缘为用户提供低延迟、高响应的服务。因此,资源利用率高、时延低的任务卸载策略成为研究的热门方向。但大部分现有的任务卸载研究是基于中心化的架构,通过中心化设施制定卸载策略并进行资源调度,容易受到单点故障的影响,且会产生较多的能耗和较高的时延。针对以上问题,提出一种基于深度Q网络(DQN)的去中心化优先级(DP-DQN)卸载策略。首先,设置通信矩阵模拟现实中边缘服务器有限的通信状态;其次,通过对任务设定优先级,使任务可以在不同边缘服务器之间跳转,保证各边缘服务器均可以自主制定卸载策略,完成任务卸载的去中心化;最后,根据任务的跳转次数为任务分配更多的计算资源,提高资源利用效率和优化效果。为了验证所提策略的有效性,针对不同DQN下参数的收敛性能进行了研究对比,实验结果表明,在不同测试情景下,DP-DQN的性能均优于本地算法、完全贪婪算法和多目标任务卸载算法,性能可提升约11%~19%。

La-Ce稀土对Q345D钢夹杂物和冲击性能的影响

通过现场试验,分析了La-Ce稀土处理对Q345D结构钢夹杂物、连铸可浇性和钢种性能的影响。结果表明,RE在Q345D结构钢中的合金收得率为21.5%;与未添加RE的炉次相比,脱硫率提高了37.5%,单位夹杂物密度从80.16个/mm^(2),降低至60.78个/mm^(2);La-Ce稀土处理前钢液中夹杂物主要是MgO-Al_(2)O_(3)-CaO复合夹杂,La-Ce稀土处理对小尺寸(D≤5μm)夹杂物的改性作用较为明显,小尺寸夹杂物改性为(La-Ce-S)和(La-Ce-Al-S-O)稀土类夹杂物;La-Ce稀土处理可以明显降低钢中MnS类夹杂物的纵横比,使MnS类夹杂物在轧制后的形貌更接近椭圆形,而没有长线形,这是Q345D结构钢横向冲击功提高20%的主要原因。

朝鲜日据时期的“阿Q”——以金史良的《Q伯爵》为中心

日据时期的朝鲜作家金史良曾受同时代中国作家鲁迅的影响,并由此创作了《Q伯爵》。金史良《Q伯爵》中“Q伯爵”的原型正是源于鲁迅《阿Q正传》中的“阿Q”,这部作品是对《阿Q正传》加以改造与重塑的一部杰作。“Q伯爵”与“阿Q”在时代背景、身份、性格等方面具有高度相似性,同时,在人物形象等方面又存在着一定差异。其原因可以从时代背景、作家对人物赋予的期待以及与其他人物之间的关系等三个方面得到解释。

基于Q学习的高超声速飞行器自抗扰控制研究

为实现高超声速飞行器姿态自抗扰控制的参数整定,提出一种模糊Q学习算法。首先,采用强化学习中的Q学习算法来实现姿态自抗扰控制参数的离线闭环快速自适应整定;然后,根据模糊控制的思路,将控制参数划分为不同区域,通过设定奖励,不断更新Q表;最后,将训练好的Q表用于飞行器的控制。仿真结果表明,相对于传统的线性自抗扰控制(linear active disturbance rejection control,LADRC)和滑模控制,基于Q学习的LADRC省去了人工调试参数的繁琐过程,且仍具有良好的跟踪效果。蒙特卡罗仿真测试结果验证了基于Q学习的LADRC的鲁棒性。

基于分数阶Zener模型的VTI黏弹性介质频变Q效应数值模拟

黏弹性是地球介质的基本属性.地震波在黏弹性介质中传播会发生振幅衰减和速度频散,导致能量和走时出现变化,影响地震资料的准确成像及解释.因此,研究地震波在黏弹性介质中的传播规律具有重要意义.当前,主要利用常Q(不随频率变化)模型(CQM)表征地震波在地球介质中的传播规律,与高温、高压或含流体介质中观测到的Q随频率变化规律不符.基于分数阶Zener模型(FZM),通过改变分数阶大小,本文研究了Q的频变特性随分数阶的变化规律.考虑速度和Q各向异性,推导了VTI介质的FZM黏弹性波方程,提出了VTI介质的频变Q效应数值模拟方法.数值算例表明:当Q随频率变化较小时,FZM与CQM方法的结果相似;当Q随频率变化剧烈时,FZM与CQM方法的模拟结果差异较大.