检索结果-南通市图书馆

Rock joint coefficients and their computerized classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining science and Technology 2019年第5期29卷 701-709页

作者： tomás Ficker Faculty of Civil Engineering Brno University of Technology60200 BrnoCzech Republic

A computerized method for determining rock joint coefficients is presented.Two relative similarity indicators are introduced to classify surface morphology of rock joints.The classification enables to compare investigated and database rock joints.such a comparison aims at finding the couple of surfaces that are distinguished by the highest dynamical conformity.The first absolute indicator results from the Fourier matrix and evaluates wavy shapes of surfaces.The second absolute indicator quantifies the heights of surface reliefs and is defined as the root mean square height of the surface outline.Numerical reliability of these indicators is tested within the surface analysis of a series of limestone specimens.Besides the computerized assessment,25 people have performed visual assessment of these limestone specimens.The results of visual assessments have been statistically processed and compared to the results received from the computerized procedure.The newly introduced absolute indicators have proved to be prospective numerical tools for evaluating joint rock coefficients.

关键词： Rock joints shear strength Joint rock coefficients Numerical indicators Computerized assessment

维普期刊数据库

草本植物的进化:解决难题的关键在于忍耐而非逃避

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2021年第5期14卷 911-919页

作者： Adam Klimes Martin Weiser tomás Koubek tomás Herben Department of Botany Faculty of ScienceCharles UniversityBenatska 212801 PragueCzech Republic Department of Functional Ecology Institute of BotanyCzech Academy of SciencesDukclska 13537901 TrehonCzecli Republic Department of Population Ecology Institute of BotanyCzech Academy of SciencesZamek 125243 PruhoniceCzech Republic

木本植物延续了其祖先被子植物的生长形态,而草本植物则不断地从中进化演变。虽然关于驱动草本植物习性进化的因素已有许多假设,但是通过舍弃地上生物质从而避免冬季冻害的能力常常被认为是促使其进化的主要力量。然而,鉴于草本植物在... 详细信息

木本植物延续了其祖先被子植物的生长形态,而草本植物则不断地从中进化演变。虽然关于驱动草本植物习性进化的因素已有许多假设,但是通过舍弃地上生物质从而避免冬季冻害的能力常常被认为是促使其进化的主要力量。然而,鉴于草本植物在反复干扰中依旧能够轻松存活,我们提出了不可预测的干扰可能比季节性霜冻更为重要的假设。我们通过比较草本植物和木本植物应对3种模拟干扰(容易预测的冬季冰冻、不易预测的春季冰冻和食草作用)的能力来验证这一假设。通过比较20种不同植物在同质园实验中的表现,我们评估了这些干扰对植物死亡和再生方面的影响。研究结果表明,在冬季冰冻条件下,比起木本植物,草本植物在存活率上并没有优势。在不易预测的春季冰冻条件下,草本植物比木本植物的存活率更高。而在模拟食草作用的条件下,草本植物的这种生存优势更大。在不可预测的条件下,草本植物相较于木本植物的生存优势表明,草本植物的生长形式可能是对不可预测的干扰的适应,这种逆境忍耐通过其损失地上生物质也能够生存的能力得以实现。因此,哺乳动物的食草行为或火灾等原因或许最有可能是木本植物向草本植物过渡的因素。

关键词：同质园实验食草作用预测性春季冰冻冬季冰冻

Following New Philanthropy by Network Ethnography:How Did the Varkey Foundation Land and Expand in Latin America?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

ECNU Review of Education 2023年第4期6卷 541-567页

作者： Iván Matovich tomás Esper Monash University Columbia University

Purpose:New philanthropy develops new forms of policy“problem-solving”through the influx of private actors’money and ideas.It adopts singular configurations across different policy spaces,with implications for education governance.We address this phenomenon by analyzing the Varkey Foundation’s(VF)“landing”and“expansion”in Latin America.VF is a global philanthropic organization registered in the United Kingdom in 2011 with a main hub in Argentina,where it landed in 2017.Design/Approach/Methods:We use network ethnography to examine the influence of new philanthropy on education governance as this phenomenon demands new methods to grasp the“realities”of governing beyond conventional ways and understanding policy mobilities.Findings:Results indicate how VF“landed”in a little pro-market space via productive uses of policy networks.The second phase of data collection and analysis presents further consolidation of VF in Argentina,its expansion into Latin America,and its establishment as a legitimate education policy actor.Originality/Value:This study provides new evidence and insights into how policy networks enable new philanthropy to land and consolidate within national boundaries and,later,across the region as a legitimate actor in education.

关键词： Education policy policy networks network ethnography new philanthropy Varkey Foundation

stochastic Models to Mitigate sparse sensor Attacks in Continuous-Time Non-Linear Cyber-Physical systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第9期76卷 3189-3218页

作者： Borja Bordel sánchez Ramón Alcarria tomás Robles Information Technologies Department Universidad Politécnica de MadridMadrid28031Spain Geospatial Information Department Universidad Politécnica de MadridMadrid28031Spain

Cyber-Physical systems are very vulnerable to sparse sensor attacks.But current protection mechanisms employ linear and deterministic models which cannot detect attacks precisely.Therefore,in this paper,we propose a new non-linear generalized model to describe Cyber-Physical systems.This model includes unknown multivariable discrete and continuous-time functions and different multiplicative noises to represent the evolution of physical processes and randomeffects in the physical and computationalworlds.Besides,the digitalization stage in hardware devices is represented too.Attackers and most critical sparse sensor attacks are described through a stochastic process.The reconstruction and protectionmechanisms are based on aweighted stochasticmodel.Error probability in data samples is estimated through different indicators commonly employed in non-linear dynamics(such as the Fourier transform,first-return maps,or the probability density function).A decision algorithm calculates the final reconstructed value considering the previous error probability.An experimental validation based on simulation tools and real deployments is also carried out.Both,the new technology performance and scalability are studied.Results prove that the proposed solution protects Cyber-Physical systems against up to 92%of attacks and perturbations,with a computational delay below 2.5 s.The proposed model shows a linear complexity,as recursive or iterative structures are not employed,just algebraic and probabilistic functions.In conclusion,the new model and reconstructionmechanism can protect successfully Cyber-Physical systems against sparse sensor attacks,even in dense or pervasive deployments and scenarios.

关键词： Cyber-physical systems sparse sensor attack non-linear models stochastic models security

Porphyrinic Acceptors forFullerene-Free MolecularPhotovoltaics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CCs Chemistry 2024年第2期6卷 276-296页

作者： Jorge Labella Juan Laforga-Martin tomás Torres Department of Organic Chemistry Universidad Aut´onoma de Madrid28049 Madrid Institute for Advanced Research in Chemical sciences Universidad Aut´onoma de MadridMadrid IMDEA—Nanociencia 28049 Madrid

Over the past few years,the development of nonfullerene acceptors(NFAs)has become a prominent focus in both organic and perovskite solar cell(OsCs and PsCs,respectively)research fields.In this context,porphyrinoids,compounds structurally related to porphyrins,have emerged as promising solar cell candidates.In contrast to the widely used fullerene acceptors,porphyrinoids exhibit strong,broad absorption properties across the UV–vis/NIR spectrum,which can be easily tuned through chemical modifications.Furthermore,they can be prepared and derivatized using cost-effective and straightforward methodologies,allowing for convenient adjustments in thin-film morphology,processability,supramolecular organization,and energy levels.Additionally,these compounds offer higher thermal and photochemical stability,resulting in longer device lifetimes compared to their fullerene-based counterparts.In this review,we outline the utilization of porphyrinoids as NFAs in OsCs and PsCs,discussing essential aspects such as design guidelines,molecular properties,and device configuration.Our goal is to inspire and further promote the development of n-type porphyrinoids,which have not yet fully unleashed their potential.

关键词： fullerene-free molecular photovoltaics nonfullerene acceptors porphyrinic acceptors n-type porphyrinoids organic and perovskite solar cells

CD34^(+ )progenitor cells as diagnostic and therapeutic targets in Alzheimer's disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第3期18卷 535-536页

作者： Daniel Romaus-sanjurjo Antía Custodia Alberto Ouro tomás sobrino NeuroAging Group(NEURAL) Clinical Neurosciences Research Laboratory(LINC)Health Research Institute of Santiago de Compostela(IDIS)Santiago de CompostelaSpain

Alzheimer’s disease(AD)is the main neurodegenerative disease leading to dementia and cognitive impairment in the elderly.Considering AD to be an epidemic,an increase from the current 50 million to more than 150 milli... 详细信息

关键词： Alzheimer progenitor impairment

维普期刊数据库

Multispecies coalescent and its applications to infer species phylogenies and cross-species gene flow

在线全文

学校读者我要写书评

暂无评论

National science Review 2021年第12期8卷 86-103页

作者： Xiyun Jiao tomá■ Flouri Ziheng Yang Department of Genetics Evolution and EnvironmentUniversity College London Department of statistics and Data science Southern University of Science and Technology

Multispecies coalescent(MsC) is the extension of the single-population coalescent model to multiple species. It integrates the phylogenetic process of species divergences and the population genetic process of coalescent, and provides a powerful framework for a number of inference problems using genomic sequence data from multiple species, including estimation of species divergence times and population sizes,estimation of species trees accommodating discordant gene trees, inference of cross-species gene flow and species delimitation. In this review, we introduce the major features of the MsC model, discuss full-likelihood and heuristic methods of species tree estimation and summarize recent methodological advances in inference of cross-species gene flow. We discuss the statistical and computational challenges in the field and research directions where breakthroughs may be likely in the next few years.

关键词： anomaly zone BPP deep coalescence gene flow Markov chain Monte Carlo multispecies coalescent species tree

Evolutionary importance of the relationship between cytogeography and climate:New insights on creosote bushes from North and south America

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2022年第5期44卷 492-498页

作者： Romina Vidal-Russell Mariana Tadey Romana Urfusova tomás Urfus Cintia Paola souto Laboratorio Ecotono-INIBIOMA(CONICET-UNComahue) Quintral1250BarilocheRío NegroArgentina Department of Botany Faculty of ScienceCharles UniversityBenátská212800PragueCzech Republic

Relationships between genome size and environmental variables suggest that DNA content might be adaptive and of evolutionary importance in plants.The genus Larrea provides an interesting system to test this hypothesis,since it shows both intra-and interspecific variation in genome size.Larrea has an amphitropical distribution in North and south American deserts,where it is most speciose.Larrea tridentata in North America shows a gradient of increasing autopolyploidy;while three of the four studied south American species are diploids,Larrea divaricata,Larrea nitida,Larrea ameghinoi,and the fourth is an allopolyploid,Larrea cuneifolia.We downloaded available focal species’georeferenced records from seven data reservoirs.We used these records to extract biologically relevant environmental variables from WorldClim at 30 arc seconds scale,to have a broad characterization of the variable climatic conditions of both regions,and a climatic envelope for each species.We estimated relative DNA content index and relative monoploid genome values,by flow cytometry,of four most abundant Larrea species throughout their respective ranges.Then we winnow the bioclimatic dataset down to uncorrelated variables and sampled locales,to analyse the degree of association between both intra-and interspecific relative DNA content and climatic variables that are functionally relevant in arid environments using Pearson correlations,general linear and mixed effects models.Within the genus Larrea,relative DNA content increases with rising temperature and decreases with rising precipitation.At the intraspecific level,all four species show relative DNA content variation across climatic conditions.Larrea is a genus that shows genome size variation correlated with climate.Our results are also consistent with the hypothesis that extreme environmental pressures may have facilitated repeated whole genome duplication events in North America,while in south America,reticulate evolution,as allopolyploidization,and speciation might have been climate-depend

关键词： DNA content Drylands Genome size Jarilla Larrea Zygophyllaceae

维普期刊数据库

structure and Activity of strigolactones： New Plant Hormones with a Rich Future

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2013年第1期6卷 38-62页

作者： Binne Zwanenburg tomás Pospísil Radboud University Nijmegen Institute for Molecules and Materials Cluster of Organic Chemistry Heyendaalseweg 135 6525AJ Nijmegen TheNetherlands Palacky University Faculty of Science Centre of the Region Haná for Biotechnological and Agricultural Research Department of Growth Regulators~lechtiteICJ 11 CZ-783 71 Olomouc Czech Republic

strigolactones (sL ) 组成作为为 striga， Orobanche，和 Pelipanchi spp 的寄生杂草的种子的萌芽兴奋剂活跃的植物荷尔蒙的一个新班，在 arbuscular mycorrhizal (AM ) 的菌丝的分叉真菌并且作为射击分叉的禁止者。在这评论，焦点在... 详细信息

strigolactones (sL ) 组成作为为 striga， Orobanche，和 Pelipanchi spp 的寄生杂草的种子的萌芽兴奋剂活跃的植物荷尔蒙的一个新班，在 arbuscular mycorrhizal (AM ) 的菌丝的分叉真菌并且作为射击分叉的禁止者。在这评论，焦点在这些 sL 的分子的特征上。在主人植物的根流出物的 sL 的出现被描述。为根据纯、适用的化学(国际理论和应用化学联合会) 规则和 at 的国际联合，一个一瞥方法被解释的 sL 的说出的协议。一些自然 sL 的全部的合成为 strigol 的所有八立体异构与细节被描述。与分配自然 sL 的正确结构遇到的问题为 orobanchol， alectrol，和 solanacol 被分析。sL 的 structureactivity 关系作为萌芽兴奋剂导致 sL 的 bioactiphore 的鉴定。和一试验为行动的模式的机制，一个模型被导出那能被用来设计并且准备活跃 sL 类似物。这个工作模型被用于象 Nijmegen-1 那样的一系列新 sL 类似物的准备，并且类似物源于简单酉同类， keto enols，并且糖。sL 的意外收获的发现模仿哪个从在 sL (适当地代替的 butenolides ) 搀被导出被报导。因为 sL 模仿，行动的一个模式也被建议。最近的新结果支持这个建议。向水解作用的 sL 和 sL 类似物的稳定性被描述，水解作用的机制的一些细节也被讨论。为有关自然 sL 的生合成的萌芽和当前的地位的蛋白质受体的尝试的隔离简短被讨论。发芽代理人被提及的某 non-sLs。为在 AM 真菌的菌丝的分叉并且在射击分叉的压抑的 sL 的 structureactivity 关系也被分析。为每原则功能，为新活跃 sL 类似物的设计的一个工作模型被描述，它的适用性和含意被讨论。三主要功能使用一个不同感觉系统，这被显示出。为 bioactivity 的立体化学的重要性为各种各样的功能被描述了。

关键词：活性关系分支结构植物激素内酯金种子发芽水解机制 AM真菌