Phylogenetic diversity of eastern Asia-eastern North America disjunct plants is mainly associated with divergence time

The underlying causes of biodiversity disparities among geographic regions have long been a fundamental theme in ecology and evolution.However,the patterns of phylogenetic diversity(PD) and phylogenetic beta diversity(PBD) of congeners that are disjunctly distributed between eastern Asia-eastern North America(EA-ENA disjuncts) and their associated factors remain unknown.Here we investigated the standardized effect size of PD(SES-PD),PBD,and potentially associated factors in 11natural mixed forest sites(five in EA and six in ENA) where abundant EA-ENA disjuncts occur.We found that the disjuncts in ENA possessed higher SES-PD than those in EA at the continental scale(1.96vs-1.12),even though the number of disjunct species in ENA is much lower than in EA(128 vs 263).SESPD of the EA-ENA disjuncts tended to decrease with increasing latitude in 11 sites.The latitudinal diversity gradient of SES-PD was stronger in EA sites than in ENA sites.Based on the unweighted unique fraction metric(UniFrac) distance and the phylogenetic community dissimilarity,PBD showed that the two northern sites in EA were more similar to the six-site ENA group than to the remaining southern EA sites.Based on the standardized effect size of mean pairwise distances(SES-MPD),nine of eleven studied sites showed a neutral community structure(-1.96 ≤SES-MPD ≤1.96).Both Pearson’s r and structural equation modeling suggested that SES-PD of the EA-ENA disjuncts was mostly associated with mean divergence time.Moreover,SES-PD of the EA-ENA disjuncts was positively correlated with temperaturerelated climatic factors,although negatively correlated with mean diversification rate and community structure.By applying approaches from phylogenetics and community ecology,our work sheds light on historical patterns of the EA-ENA disjunction and paves the way for further research.

Divergence time, historical biogeography and evolutionary rate estimation of the order Bangiales (Rhodophyta) inferred from multilocus data

Bangiales is the only order of the Bangiophyceae and has been suggested to be monophyletic. This order contains approximately 190 species and is distributed worldwide. Previous molecular studies have produced robust phylogenies among the red algae, but the divergence times, historical biogeography and evolutionary rates of Bangiales have rarely been studied. Phylogenetic relationships within the Bangiales were examined using the concatenated gene sets from all available organellar genomes. This analysis has revealed the topology((( Bangia, Porphyra) Pyropia) Wildemania). Molecular dating indicates that Bangiales diversifi ed approximately 246.40 million years ago(95% highest posterior density(HPD)= 194.78–318.24 Ma, posterior probability(PP)=0.99) in the Late Permian and Early Triassic, and that the ancestral species most likely originated from eastern Gondwanaland(currently New Zealand and Australia) and subsequently began to spread and evolve worldwide. Based on pairwise comparisons, we found a slower rate of nucleotide substitutions and lower rates of diversifi cation in Bangiales relative to Florideophyceae. Compared with Viridiplantae(green algae and land plants), the evolutionary rates of Bangiales and other Rhodophyte groups were found to be dramatically faster, by more than 3-fold for plastid genome(ptDNA) and 15-fold for mitochondrial genome(mtDNA). In addition, an average 2.5-fold lower dN/dS was found for the algae than for the land plants, which indicates purifying selection of the algae.

面向稀疏数据的协同过滤算法相似度

针对数据稀疏加剧导致传统相似度模型的推荐准确性低的问题,提出一种混合的协同过滤相似度模型。引入Jensen-Shannon(JS)散度作为基函数,利用全局评级概率分布衡量用户间评级偏好相似度。定义融合评级值的结构型相似度作为权重因子,针对用户的共同评级项目设计差异化的相似度计算方式,提高相似用户的区分度,得到基于相对区间跨度的相似度。在不同稀疏度数据集上与7种具有代表性的相似度方法进行对比实验,其结果表明了所提方法在预测和推荐准确性指标上均有良好性能。

基于K-L散度的核磁共振波谱数据尺度缩放方法

在基于核磁共振(NMR)的代谢组学数据分析中,尺度缩放是关键的预处理步骤之一,其主要目的是通过调整数据的方差结构,改善后续的多变量统计分析的结果。从信息熵的角度出发,利用KullbackLeibler(K-L)散度来度量不同实验分组的生物样品的1 H NMR波谱数据的差异程度,并结合单位方差缩放法,提出一种基于K-L散度的尺度缩放方法。该方法先利用单位方差法将数据各变量的标准差调整到同一水平上,再利用K-L散度对各变量进行有监督地加权,增强重要变量、减弱无关变量。由于K-L散度是在概率分布的意义上度量数据间的差异程度,且对于高斯和非高斯分布的数据均适用,因此能更准确地度量不同实验分组样品的1 H NMR波谱数据的差异性,从而更有效地地对谱数据的重要变量进行识别和加权。人群尿液1 H NMR波谱数据的分析结果表明,基于K-L散度的尺度缩放方法能有效抑制噪声变量,同时很好地区分特征变量和非特征变量;提高主成分回归(PCR)模型的判别能力;改善偏最小二乘回归判别分析(PLS-DA)模型的解释能力、预测能力以及对特征代谢物的辨识能力。

ESG评级分歧与企业权益资本成本

基于2009—2021年间中国A股上市公司的研究样本,实证检验了ESG评级分歧对企业权益资本成本的影响,结果发现,ESG评级分歧导致了企业权益资本成本的增加,即ESG评级分歧越大企业的权益资本成本越高。异质性检验表明,与ESG评级高的企业相比,ESG评级分歧对企业权益资本成本的不利影响在ESG评级低的企业中表现得更加明显。研究结论丰富了企业权益资本成本影响因素的相关研究,为进一步完善ESG评级体系和降低企业权益资本成本提供了新的依据与思路。

ESG评级分歧与企业经营风险

随着ESG意识的提高和可持续发展的重要性日益突显,ESG评级已成为学术界和实务界讨论的重点问题,但目前中国ESG评级标准并不统一,不同评级机构给出的评分有较大分歧,这是否会对企业经营风险产生影响?基于此,本文以2015—2022年中国A股上市公司为样本,使用华证、万德、富时罗素、商道融绿、盟浪、彭博6家评级机构的评级结果构建ESG评级分歧指标,实证检验了ESG评级分歧对企业经营风险的影响。结果显示,ESG评级分歧显著提高了企业经营风险,这一结论在经过一系列内生性稳健性检验后依然成立。机制检验发现,ESG评级分歧通过加剧信息不对称以及抑制投资者情绪进而提高企业经营风险。异质性分析表明,ESG评级分歧对企业经营风险的提升作用在非国有企业、信息质量较差的企业和高市场化企业更强。进一步研究发现,相比于ESG评级机构间分析差异,被评级企业本身ESG信息披露不规范是ESG评级分歧加剧企业经营风险的主要原因。研究结论为监管机构规范ESG评级标准以引导企业规范披露,推动中国ESG评级体系建设提供了重要借鉴。

ESG评级分歧与企业劳动雇佣

企业是吸纳就业的主力军,而ESG评级分歧引致企业未来可持续发展的不确定性,可能会对企业的劳动雇佣决策产生影响。本文利用2015—2022年中国沪深A股上市企业样本,研究发现ESG评级分歧抑制了企业劳动雇佣。机制检验发现,ESG评级分歧一方面在劳动力需求端增加企业融资约束和经营风险,另一方面在劳动力供给端损害企业信息透明度和声誉,降低对劳动力的吸引力,从而减少企业劳动雇佣规模。异质性分析发现,ESG评级分歧抑制企业雇佣的效应主要存在于非国有企业、小规模企业、上市年限较短的企业和重污染行业企业。进一步研究表明,ESG评级分歧还会影响企业人力资本结构,导致企业雇佣更多高技能员工,减少雇佣低技能员工。此外,ESG评级分歧也促使企业支付高薪酬以增加对高技能人才的吸引力。本文的研究丰富了ESG评级分歧经济后果和企业劳动雇佣影响因素的相关文献,对于规范ESG信息披露标准、促进高质量充分就业也具有重要的启示。

上市公司ESG评级分歧的审计溢价效应——基于信息生产的视角

近年来,ESG评级发挥着日益重要的审计定价功能并影响着审计质量,但囿于缺乏完善的评级体系,不同评级机构间存在明显分歧,导致其对审计溢价产生不确定性影响。基于此,以2015—2020年沪深A股上市企业为样本,实证探究ESG评级分歧的审计溢价效应。研究发现,ESG评级分歧会显著提高审计定价,但是审计费用的增加并未显著改善审计质量。机制检验发现,ESG评级分歧延长了审计时滞、增加了关键审计事项的披露篇幅,并加剧了企业的财务风险和舞弊风险,即审计费用的增加是对其工作量及风险增加的补偿,而未能显著提升审计质量。异质分析发现,企业及时的信息披露、分析师的准确预测以及审计师的丰富经验能够缓解ESG评级分歧的负面冲击。

The Physiological Response during Divergent Thinking

Our research studied the physiological response of participants during a creative task to investigate if a person’s psychophysiological state was correlated with divergent thinking performance. We used heart rate variability as our physiological measure. We asked 50 participants to perform a cognitive task that assessed their divergent thinking skills and recorded their heart rate and heart rate variability (HRV) before and during the task. Frequency domain analysis was performed on the HRV. The results showed that there was a significant negative correlation between log-transformed low frequency HRV power and the number of “divergent thinking” words generated. Our results suggest that a person’s psychophysiological state is correlated with their divergent thinking performance, and that attention and motivation may be important factors, however this needs further research. Our findings also suggest that being in a relaxed state before the start of a creative task is not a predictor of creative performance.

RATE OF CONVERGENCE AND EXPANSION OF RNYI ENTROPIC CENTRAL LIMIT THEOREM

We obtain the expansion of Renyi divergence of order α （0 〈 α 〈 1） between the normalized sum of IID continuous random variables and the Caussian limit under minimal moment conditions via Edgeworth-type expansion. The rate is faster than that of Shannon case, which can be used to improve the rate of convergence in total variance norm.

ESG评级分歧与股价同步性

随着对可持续发展的日益重视,ESG评级结果已经成为投资者进行决策时的重要参考,但目前国内外各ESG评级机构的评级结果各异,存在较大分歧。以2015—2021年中国A股上市公司为样本,使用商道融绿、和讯、润灵环球和彭博4家评级机构的评级结果构建ESG评级分歧衡量指标,实证检验了ESG评级分歧对股价同步性的影响。研究发现:ESG评级分歧显著提高了被评级企业的股价同步性,表明ESG评级分歧存在“噪音效应”。在经过一系列稳健性检验后结论依然成立。进一步研究发现:ESG评级分歧对股价同步性的正向影响在于加剧了市场信息不对称;当上市公司信息环境较好,以及投资者具备较强的信息解读和分析能力时,可以缓解ESG评级分歧产生的“噪音效应”。研究结论为监管机构规范ESG评级标准,推动资本市场定价效率提升提供政策建议。

ESG评级分歧与分析师盈余预测准确性

ESG评级是分析师盈余预测的重要参考依据,然而不同评级机构提供的评级信息却存在较大分歧。基于此,以中国资本市场2009—2021年A股上市公司为样本,实证检验ESG评级分歧对分析师盈余预测准确性的影响。研究发现:(1)ESG评级分歧显著降低了分析师盈余预测准确性。(2)机制检验显示,ESG评级分歧通过增加分析师信息处理成本,进而对盈余预测准确性产生负向影响。(3)异质性分析表明,经济政策不确定性会加剧ESG评级分歧对分析师盈余预测准确性的消极影响,而良好的内部控制能够缓解ESG评级分歧对分析师盈余预测准确性的负向影响。(4)经济后果检验揭示,ESG评级分歧对分析师盈余预测准确性的抑制作用加剧了企业融资约束。研究结论有助于深入理解ESG评级分歧的信息价值和经济后果,同时丰富了分析师盈余预测质量影响因素的相关文献。

ESG评级分歧与审计风险溢价

ESG评级分歧反映了不同机构对同一企业ESG表现的评价差异,这可能导致利益相关者对企业ESG表现的认知偏差。本文以2009-2021年我国资本市场A股上市公司为样本,从审计风险溢价视角研究了ESG评级分歧的经济后果。研究发现,ESG评级分歧越大,企业的审计风险溢价越高。机制检验发现,审计风险在ESG评级分歧与风险溢价之间发挥了部分中介作用。异质性分析表明,在治理水平较高的企业中,ESG评级分歧与审计风险溢价之间的正向关系被削弱;而市场竞争地位、地区法制环境增强了上述正向关系。本文将ESG表现延伸至ESG评级分歧,对理论界和实务界深入理解ESG评级分歧具有重要的参考价值,丰富了审计风险溢价影响因素相关研究。

ESG评级分歧影响审计师风险应对行为吗?——基于关键审计事项披露的视角

不同评级机构对同一家公司给出的ESG评级存在分歧,这会给企业带来怎样的冲击?本文以2015—2021年沪深A股上市公司作为研究样本,从关键审计事项披露的视角切入,实证检验ESG评级分歧对审计师风险应对行为的影响。研究发现:ESG评级分歧促使审计师披露更多的关键审计事项来应对风险;机制检验表明,ESG评级分歧通过提高经营风险、代理成本和声誉风险促进关键审计事项披露数量的提升;进一步研究发现,对非国有企业和市场化水平较高地区的企业而言,ESG评级分歧与关键审计事项披露的正向关系更加显著。本文弥补了国内ESG评级分歧相关研究的不足,也为审计师规避风险、保障审计监督质量提供了重要借鉴。

ESG评级分歧的国内外表现、原因及对策

ESG(Environmental、Social和Governance)评级是投资者和管理层决策的重要依据。然而,大型评级机构的ESG评级出现了严重的分歧,这导致使用不同数据库的ESG评级数据可能得出完全不同的结论。这一现象引发了学界和业界的广泛关注和批评。文章旨在梳理研究ESG分歧现象的若干关键文献,总结ESG分歧的具体来源和深层次原因,并对我国的ESG评级分歧现象进行实证分析。最后,提出了若干应用ESG评级数据的建议。

ESG评级体系的差异与优化研究——来自彭博和万得的证据

完备的ESG评级体系是实现我国“双碳”目标和引导资本市场绿色发展的重要抓手。本文以2018—2020年彭博和万得的ESG评级数据为样本,采用差异分解和权重估计等方法,实证分析了ESG评级差异细分机制。研究发现:彭博和万得的ESG评级在分项E的指标得分和赋权上具有较强的一致性,分项S的指标得分相对权重差异较大,分项G的权重差异贡献率较高;两家ESG评级均具有较强的时间效应和行业异质性,而在区域异质性方面,彭博ESG评级较弱。

Accurate estimation of the largest divergence rate for a class of the 3rd-order switched linear systems

The largest divergence rate is a characterization of the stability behavior for dynamic systems, which has been proven to be equal to the least possible common matrix set measure （extreme measure） of switched linear systems. To determine the largest divergence rate is an interesting and open problem. In this paper, an algorithm is introduced to estimate the largest divergence rate for a class of the 3rd-order switched linear systems, by which any desired accurate estimation could be derived. It explores a way to determine the largest divergence rate for the 3rd-order switched linear systems. Furthermore, the accurate estimation provides a qualitative and quantitative analysis for guaranteed stability of switched linear systems.

Testing relative evolutionary rates and estimating divergence times among six genera of Rhizophoraceae using cpDNA and nrDNA sequences

The molecular phylogenetic trees of 10 species representing 6 genera of the family Rhizophoraceae have been constructed using the sequences of chloroplast genes ma/K and rbcL as well as the ITS regions of nuclear ribosomal DMA. Relative-rate tests between lineages in these phylogenetic trees have been performed. On the basis of the results of the relative-rate tests and related molecular evolutionary rate data, the divergence times between the lineages are estimated as follows: ( i) the first divergence time in these genera is 132.25 million years ago (mya); (ii) the average divergence time between two tribes, i.e. inland Legnotideae (except Carallia brachiata) and mangrove Rhizophoreae, is 64.13 mya; and (iii) the average divergence time between two inland species, C. garciniaefolia and C. pectinifolia, is 19.92 mya.

DIVERGENCE RATE OF STATE OF AR SYSTEMS WITH UNSTABLE UNIT ROOTS

为随机的系统的噪音顺序的加权的和的顺序被在概率使用限制理论估计。然后，鞅差别顺序的噪音驾驶的不稳定的 ARsystem 的状态的分叉率被建立。

羊草两个趋异类型的光合生理生态特性比较的初步研究

对羊草（Ａｎｅｕｒｏｌｅｐｉｄｉｕｍ ｃｈｉｎｅｎｓｅ）种群的两个趋异类型——灰绿型羊草与黄绿型羊草的光合生理生态特性进行了研究，比较了同一生境条件下，两种趋异类型羊草的光合速率、蒸腾速率的日变化，以及两个羊草趋异类型的光合速率对光辐射强度、气温、相对湿度、叶温与气孔扩散阻力的响应。结果表明，同一生境条件下，灰绿型羊草的光合速率与蒸腾速率相对较高，两者的饱和光合速率分别为２３．２与１８．８μｍ ｏｌＣＯ２／ｍ ２·ｓ，光饱和点分别为１３６７．６与１３８７．９μｍ ｏｌ／ｍ ２·ｓ，光补偿点分别为９．８与１４．０μｍ ｏｌ／ｍ ２·ｓ；灰绿型羊草与黄绿型羊草对光强度、气温、相对湿度、叶温、气孔扩散阻力的响应均有显著差异。实验测得的结果说明，同一生境条件下羊草两个趋异类型的光合生理特性变异是明显的，羊草这种生理上的变异为确定两个趋异类型是否为两个生态型提供了一些生理学方面的证据。