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Taxonomic Distinctness of Macrofauna as an Ecological Indicator in Laizhou Bay and Adjacent Waters 被引量:9
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作者 ZHOU Hong HUA Er ZHANG Zhinan 《Journal of Ocean University of China》 SCIE CAS 2010年第4期350-358,共9页
In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tes... In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising. 展开更多
关键词 Taxonomic distinctness MACROFAUNA ecological indicator BIODIVERSITY Laizhou Bay Bohai Sea
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Preparation of the UPOV Guidelines for the Conduct of Tests for Distinctness, Uniformity and Stability–Tea Plant [Camellia sinensis (L.) O. Kuntze] 被引量:8
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作者 CHEN Liang YU Fu-lian +3 位作者 YAO Ming-zhe Lü Bo YANG Kun DU Yuan-yuan 《Agricultural Sciences in China》 CAS CSCD 2008年第2期224-231,共8页
Distinctness, Uniformity and Stability (DUS) testing is the technical base of Plant Variety Protection (PVP) and the scientific basis for the approval of Plant Breeder's Rights (PBR). DUS Test Guidelines are no... Distinctness, Uniformity and Stability (DUS) testing is the technical base of Plant Variety Protection (PVP) and the scientific basis for the approval of Plant Breeder's Rights (PBR). DUS Test Guidelines are not only the technical manuals for the DUS testing authorities to conduct the testing, but also the technical standards for the competent authorities to examine the DUS of new varieties of plants. Tea plant, originated from Yunnan Province, China, is a very important woody cash species in the world. The International Union for the Protection of New Varieties of Plants (UPOV) DUS Test Guidelines for tea plant is the first Test Guidelines prepared by China for the UPOV. In this article, the subject, selection, and determination of characteristics, states of expression of characteristics and the selection of example varieties, assessment of the UPOV DUS Test Guidelines for tea plant were elucidated in detail. Finally, the proposal of PVP for tea plant in China was also proposed. The preparation of UPOV DUS Test Guidelines for tea plant will have important significance both for promoting the development of PVP and increasing the status of international PVP fields for China. 展开更多
关键词 distinctness Uniformity and Stability Plant Variety Protection tea plant Test Guidelines International Union for the Protection of New Varieties of Plants (UPOV)
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Assessment of wheat variety distinctness using SSR markers 被引量:3
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作者 WANG Li-xin QIU Jun +4 位作者 CHANG Li-fang LIU Li-hua LI Hong-bo PANG Bin-shuang ZHAO Chang-ping 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第10期1923-1935,共13页
Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair ... Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat(SSR) markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value(GSV) ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably. 展开更多
关键词 wheat variety distinctness assessment SSR markers
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Construction of EST-SSR Databases for Effective Cultivar Identification and Their Applicability to Complement for Lettuce (Lactuca sativa L.) Distinctness Test 被引量:4
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作者 Jee-Hwa Hong Yong-Sham Kwon +1 位作者 Raghvendra Kumar Mishra Doo Hwan Kim 《American Journal of Plant Sciences》 2015年第1期113-125,共13页
The objectives of this study were to construct a database of expressed sequence tag (EST)-simple sequence repeat (SSR) markers to identify lettuce cultivars. A set of 370 EST-SSR primer pairs were applied for fingerpr... The objectives of this study were to construct a database of expressed sequence tag (EST)-simple sequence repeat (SSR) markers to identify lettuce cultivars. A set of 370 EST-SSR primer pairs were applied for fingerprinting the lettuce cultivars. Fifty-eight EST-SSR markers showed hy-per-variability and were able to differentiate 92 cultivars. A total of 176 polymorphic amplified fragments were obtained by the 58 markers, and two to eight SSR alleles were detected for each l&degCus with an average of three alleles per locus. Average polymorphism information content (PIC) was 0.425, ranging from 0.022 to 0.743. Cluster analysis was based on Jaccard’s distance coefficients using the method of unweighted pair group. In this method we used arithmetical averages (UPGMA) algorithm categorized 4 major groups, which were in accordance to morphological traits. The eight cultivars of three groups with 100% genetic similarity through SSR analysis were investigated by phenotypic traits. These cultivars including these pairs are very similar in 27 morphological characteristics. Therefore, these EST-SSR markers could be used to select similar cultivars through management of reference collection to complement distinctiveness test of lettuce cultivars. 展开更多
关键词 Expressed SEQUENCE Tags Simple SEQUENCE REPEATS Cultivar Identification distinctness TEST
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Taxonomic Distinctness of the Intertidal Fish Community on the Pacific Coast of Baja California Sur, México 被引量:2
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作者 Emelio Barjau-González José Ange Armenta-Quintana +1 位作者 Juan Manuel López-Viva Eleonora Romero-Vadillo 《Open Journal of Marine Science》 2019年第2期86-97,共12页
The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such... The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such as temperature and salinity are highly variable. Fish communities that inhabit these tide pools are also exposed to environmental variability;therefore it is important to look at fish community structure in relation to important environmental factors such as temperature, salinity and dissolved oxygen on tide pools during spring tides, time of greater exposure to air. Therefore, the aim of the present study was to analyze the variation of the taxonomic distinctness of intertidal fish communities considering temperature, salinity and dissolved oxygen of the water that remains trapped in the tide pools during low tide. Visual census surveys were carried out monthly, from January to December 2015, in the intertidal zone of El Faro during spring tides on full moon days, when fluctuations of environmental variables are significant. Total extension of the census surveys was 156 × 5 m (780 m2). A total of 145 tide pools were sampled and divided in three groups (small, medium and large) according to size and depths that ranged from 20 to 45 cm. Temperature, salinity and dissolved oxygen fluctuate throughout the year of study. Thermal difference between open ocean and tide pools ranged from 3.5°C to 4.5°C. A total of 3757 organisms from 22 species, 12 families, four orders and one class were recorded. When comparing taxonomic distinctness and average taxonomic distinctness between months and tide pools of different sizes, values fell within the confidence intervals in the tunnel and were located close to the mean. 展开更多
关键词 TAXONOMIC distinctness EXPOSED COAST CLIMATE CHANGE
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Relationship between species richness,taxonomic distinctness,functional diversity,and local contribution toβdiversity and effects of habitat disturbance in the riparian spider community of the Ganga River,India 被引量:1
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作者 Kritish De Amar Paul Singh +4 位作者 Arkojyoti Sarkar Kritika Singh Manju Siliwal Virendra Prasad Uniyal Syed Ainul Hussain 《Ecological Processes》 SCIE EI CSCD 2023年第1期204-216,共13页
Background In the riverine riparian ecosystem,particularly in India,the knowledge of the effects of habitat disturbance on taxonomic distinctness,functional diversity,and local contribution toβdiversity(LCBD)of spide... Background In the riverine riparian ecosystem,particularly in India,the knowledge of the effects of habitat disturbance on taxonomic distinctness,functional diversity,and local contribution toβdiversity(LCBD)of spider community is elusive.The present study examined the relationships between the index of taxonomic distinctness(Δ^(+)),index of variation in taxonomic distinctness(λ^(+)),functional evenness(FEve),functional divergence(FDiv),functional dispersion(FDis),and LCBD of spider community of the Ganga River and the effects of habitat disturbance on these indices.A total of 27 sampling sites were selected along the bank of the Ganga River.Based on the rating of the disturbance scores,the sites were classified into lowly,moderately,and highly disturbed sites.To understand the relationships between species richness,Δ^(+),λ^(+),FDis,FDiv,FEve,LCBD,and habitat disturbance score,Pearson’s correlation was calculated,followed by the linear regression model.The one-way multivariate analysis of variance was used to find differences in taxonomic distinctness and functional diversity in the different disturbed sites.Results Significant relationships were found betweenλ^(+)andΔ^(+),FDis andΔ^(+),FDis andλ^(+),FDiv and species richness,FEve and species richness,FEve andλ^(+),FEve and habitat disturbance,LCBD and FEve,and LCBD and habitat disturbance.A significant difference was present in the indices of functional diversity between the lowly,moderately,and highly disturbed sites.Agriculture,garbage dump,human settlement,and created embankment influenced the spider community’sλ^(+),FEve,and LCBD.Conclusion Unrestrained anthropogenic activities exacerbate habitat disturbance by affecting ecological processes.Thus,understanding linkages between ecosystem disturbance,taxonomic,functional,andβdiversity can be fundamental to managing and conserving natural resources.This work highlights the importance of including taxonomic and functional diversity to comprehend the impact of habitat disturbance on riverine riparian spiders beyond just the number of species.An integrated taxonomic and functional diversity approach coupled withβdiversity can be used to support environmental assessment,restoration,and conservation planning of the biological resources of the Ganges River. 展开更多
关键词 Habitat disturbance Taxonomic distinctness Functional evenness Functional divergence Functional dispersion Local contribution to beta diversity Spider community Riparian area Ganga River
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CDS:A Fold-change Based Statistical Test for Concomitant Identification of Distinctness and Similarity in Gene Expression Analysis
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作者 Nicolas Tchitchek José Felipe Golib Dzib +3 位作者 Brice Targat Sebastian Noth Arndt Benecke Annick Lesne 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2012年第3期127-135,共9页
The problem of identifying differential activity such as in gene expression is a major defeat in biostatistics and bioinformatics. Equally important, however much less frequently studied, is the question of similar ac... The problem of identifying differential activity such as in gene expression is a major defeat in biostatistics and bioinformatics. Equally important, however much less frequently studied, is the question of similar activity from one biological condition to another. The fold- change, or ratio, is usually considered a relevant criterion for stating difference and similarity between measurements. Importantly, no statistical method for concomitant evaluation of similarity and distinctness currently exists for biological applications. Modern micro- array, digital PCR (dPCR), and Next-Generation Sequencing (NGS) technologies frequently provide a means of coeff^cient of variation estimation for individual measurements. Using fold-change, and by making the assumption that measurements are normally distributed with known variances, we designed a novel statistical test that allows us to detect concomitantly, thus using the same formalism, differ- entially and similarly expressed genes (http:]]cds.ihes.fr). Given two sets of gene measurements in different biological conditions, the probabilities of making type I and type II errors in stating that a gene is differentially or similarly expressed from one condition to the other can be calculated. Furthermore, a confidence interval for the fold-change can be delineated. Finally, we demonstrate that the assumption of normality can be relaxed to consider arbitrary distributions numerically. The Concomitant evaluation of Distinctness and Similarity (CDS) statistical test correctly estimates similarities and differences between measurements of gene expression. The imple- mentation, being time and memory efficient, allows the use of the CDS test in high-throughput data analysis such as microarray, dPCR, and NGS experiments. Importantly, the CDS test can be applied to the comparison of single measurements (N = 1) provided the var- iance (or coefficient of variation) of the signals is known, making CDS a valuable tool also in biomedical analysis where typically a single measurement per subject is available. 展开更多
关键词 Statistical test Fold-change distinctness SIMILARITY Gene expression Single measurement Patient study
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Wellbore breakouts in heavily fractured rocks:A coupled discrete fracture network-distinct element method analysis 被引量:1
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作者 Yongcun Feng Yaoran Wei +4 位作者 Zhenlai Tan Tianyu Yang Xiaorong Li Jincai Zhang Jingen Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1685-1699,共15页
Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout a... Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout analyses were based on continuum mechanics.In addition to failure in intact rocks,wellbore breakouts can also be initiated along natural discontinuities,e.g.weak planes and fractures.Furthermore,the conventional models in wellbore breakouts with uniform distribution fractures could not reflect the real drilling situation.This paper presents a fully coupled hydro-mechanical model of the SB-X well in the Tarim Basin,China for evaluating wellbore breakouts in heavily fractured rocks under anisotropic stress states using the distinct element method(DEM)and the discrete fracture network(DFN).The developed model was validated against caliper log measurement,and its stability study was carried out by stress and displacement analyses.A parametric study was performed to investigate the effects of the characteristics of fracture distribution(orientation and length)on borehole stability by sensitivity studies.Simulation results demonstrate that the increase of the standard deviation of orientation when the fracture direction aligns parallel or perpendicular to the principal stress direction aggravates borehole instability.Moreover,an elevation in the average fracture length causes the borehole failure to change from the direction of the minimum in-situ horizontal principal stress(i.e.the direction of wellbore breakouts)towards alternative directions,ultimately leading to the whole wellbore failure.These findings provide theoretical insights for predicting wellbore breakouts in heavily fractured rocks. 展开更多
关键词 Wellbore breakout Discrete fracture network(DFN) Distinct element method(DEM) Heavily fractured rocks
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A Comparison of Phonemes Between Chinese and Italian and Its Application in Pronunciation Teaching
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作者 Yilun Tang 《Journal of Contemporary Educational Research》 2025年第8期229-236,共8页
This paper examines the phonemes of Chinese and Italian,conducting a statistical analysis and comparing their distinctive feature oppositions to identify challenges in phonetic learning,thereby offering suggestions fo... This paper examines the phonemes of Chinese and Italian,conducting a statistical analysis and comparing their distinctive feature oppositions to identify challenges in phonetic learning,thereby offering suggestions for teaching Chinese and Italian pronunciation.The study is divided into four parts:the first introduces the phonological definition of phonemes and delineates their scope in this context;the second compares the vowel and consonant systems of both languages,presenting foundational data on their similarities;the third analyzes the phonemic oppositions unique to each language,highlighting key differences;and the fourth proposes methods and recommendations for mastering the phonetic systems of both languages based on these differences. 展开更多
关键词 CHINESE ITALIAN PHONEME Distinctive phonological features Pronunciation teaching
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Positive and negative risk-taking behaviors in adolescents:Distinct characteristics,interrelationships,and influencing factors
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作者 Jun-Jie Zhang En-Na Wang 《World Journal of Psychiatry》 2025年第6期21-33,共13页
Adolescence is a crucial period marked by significant developmental changes,during which risk-taking behaviors can be both a normative part of development and a potential source of concern.However,prior research has f... Adolescence is a crucial period marked by significant developmental changes,during which risk-taking behaviors can be both a normative part of development and a potential source of concern.However,prior research has focused predominantly on the adverse aspects of risk-taking(i.e.,negative risk-taking),overlooked the positive counterpart(i.e.,positive risk-taking),and lacked a detailed examination of both.This study aims to elucidate the distinct characteristics and interrelationships of positive and negative risk-taking behaviors among adoles-cents and to identify the key factors that influence these behaviors.Through a comprehensive synthesis of theoretical and empirical literature,we explore the multifaceted nature of risk-taking,highlighting its complex influencing factors,including individual traits,family dynamics,peer influence,school environment,and broader community contexts.By identifying the shared and unique factors contributing to positive and negative risk-taking behaviors,we can enable adolescents to navigate this complex stage of life and design targeted interventions.Future research directions include the application of person-centered approaches,the implementation of longitudinal tracking and the interactive effects of influencing factors,among other aspects. 展开更多
关键词 ADOLESCENCE Positive risk-taking Negative risk-taking Distinct characteristics INTERRELATIONSHIPS Influencing factors
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Exploring Distinct Ethical Challenges Deriving from AI-RPA Technical Characteristics
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作者 Jelle Tuls 《Journal of Computer and Communications》 2025年第2期16-27,共12页
Addressing the existing gap in ethical research surrounding distinct technical characteristics of Robotic Process Automation enhanced with Artificial Intelligence (AI-RPA), this analysis examines the unique ethical di... Addressing the existing gap in ethical research surrounding distinct technical characteristics of Robotic Process Automation enhanced with Artificial Intelligence (AI-RPA), this analysis examines the unique ethical dimensions by positioning AI-RPA as a distinct technological subdivision. From an analytical perspective, this study highlights key characteristics such as minimal reliance on programming, rapid development cycles, and restricted algorithmic control, which differentiate AI-RPA from traditional AI systems. These characteristics underscore the need for tailored ethical considerations, to identify ethical perils within AI-RPA’s technological origins. By positioning AI-RPA as a distinct subdivision and examining its unique characteristics alongside their emerging ethical challenges, this paper enriches the evolving discourse on AI ethics, providing valuable insights for researchers, policymakers, and organizations implementing AI-RPA technologies. 展开更多
关键词 Robotic Process Automation Artificial Intelligence AI-RPA Digital Ethics Distinct Characteristics
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Environmental and evolutionary factors jointly shape life-history trait diversity of terrestrial vertebrates across China
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作者 Zi-Jian Sun Bao-Jun Sun +5 位作者 Yan-Ping Wang Guo-Huan Su Jia-Tang Li Jian-Ping Jiang Sheng-Qi Su Tian Zhao 《Zoological Research》 2025年第5期983-995,共13页
Life-history traits represent evolutionary adaptations that mediate responses to external environments.Analyzing variation in these traits provides valuable insights into macroecological processes and supports the dev... Life-history traits represent evolutionary adaptations that mediate responses to external environments.Analyzing variation in these traits provides valuable insights into macroecological processes and supports the development of effective conservation and restoration strategies.However,large-scale biogeographic patterns in life-history trait diversity among terrestrial vertebrates remain insufficiently characterized,and the processes shaping these patterns are not well understood.This study integrated life-history and spatial distribution data for 2334 terrestrial vertebrate species in China,including 398 amphibians,211 reptiles,541 mammals,and 1184 birds,to evaluate spatial patterns of trait diversity and identify underlying drivers.Assemblages in South and Southwest China exhibited high species richness,substantial assemblage-level evolutionary distinctiveness,expanded trait volumes,and elevated trait densities compared to null expectations,indicating roles as both evolutionary museums and cradles.In contrast,assemblages on the Tibetan Plateau showed expanded trait volumes but low trait densities,reflecting niche expansion among limited taxa.These findings emphasize the importance of niche packing before assemblages reach environmental carrying limits.Assemblages with high evolutionary distinctiveness tended to display high trait volumes and low trait densities,suggesting a consistent relationship between phylogenetic structure and functional diversification.Among the four groups,amphibians showed the highest sensitivity to environmental variation,highlighting the need for focused conservation efforts.Overall,this study revealed pronounced spatial heterogeneity in trait diversity across China,shaped by species richness,evolutionary distinctiveness,and environmental variation,providing valuable insights for refining conservation priorities for terrestrial vertebrate taxa. 展开更多
关键词 Trait density Trait variance Evolutionary distinctiveness Niche expansion Cross-taxon congruence
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Effect of Pressure on the Metal-Insulator Transition of the Cubic Pyrochlore Tl_(2)Ru_(2)O_(7)
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作者 Yuanyuan Jiao Ziyi Liu +3 位作者 Ningning Wang Bosen Wang Jianping Sun Jinguang Cheng 《Chinese Physics Letters》 2025年第5期169-175,共7页
The cubic pyrochlore Tl_(2)Ru_(2)O_(7) undergoes concurrently a metal–insulator transition (MIT) and a first-order structural transition at T_(MIT)≈120 K,below which the system was found to form one-dimensional spin... The cubic pyrochlore Tl_(2)Ru_(2)O_(7) undergoes concurrently a metal–insulator transition (MIT) and a first-order structural transition at T_(MIT)≈120 K,below which the system was found to form one-dimensional spin-one Haldane chains associated with an orbital ordering of Ru-4d electrons.With an aim to tune and access distinct ground states with strong entanglements of multiple degrees of freedom,i.e.,spin,orbital,charge,and lattice,we utilize a high-pressure approach to regulate the MIT of this system.Our detailed resistivityρ(T) measurements on the polycrystalline Tl_(2)Ru_(2)O_(7) samples under various hydrostatic pressures indeed reveal an unusual evolution of the electronic ground states.At first,the MIT is suppressed monotonically from 120 K at ambient to about 70 K at 1.5 GPa and then vanishes suddenly at about 1.8 GPa without achieving a metallic ground state.Meanwhile,the system evolves into a semiconducting ground state with magnitude ofρ(T) in the entire temperature range enhanced gradually by further increasing pressure.Prior to the abrupt disappearance of MIT,a new electronic order manifested as a kink-like anomaly inρ(T) emerges at T_(0)>T_(MIT) at 1.2 GPa and it continues to increase with pressure,producing a tricritical-point-like behavior in the T–P phase diagram of Tl_(2)Ru_(2)O_(7).The presence of two successive transitions at T_(0 )and T_(MIT )in the pressure range 1.2–1.5 GPa indicates an inhomogeneous electronic state nearby the tricritical point.At P≥3 GPa,another broad anomaly emerges inρ(T) at T_(1)>T_(0),and T_(1)continuously increases with pressure,dividing the semiconductingρ(T) into distinct thermally activated regions.These rich phenomena in the pressurized Tl_(2)Ru_(2)O_(7) should originate from the complex interplay of strongly entangled multiple quantum degrees of freedom in the system near the localized-to-itinerant crossover regime. 展开更多
关键词 Tl Ru O electronic ground states metal insulator transition tune access distinct ground states orbital ordering cubic pyrochlore pressure
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An intelligent algorithm to fast and accurately detect chaotic correlation dimension
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作者 Mengyan Shen Miaomiao Ma +1 位作者 Zhicheng Su Xuejun Zhang 《River》 2025年第2期253-264,共12页
Detecting the complexity of natural systems,such as hydrological systems,can help improve our understanding of complex interactions and feedback between variables in these systems.The correlation dimension method,as o... Detecting the complexity of natural systems,such as hydrological systems,can help improve our understanding of complex interactions and feedback between variables in these systems.The correlation dimension method,as one of the most useful methods,has been applied in many studies to investigate the chaos and detect the intrinsic dimensions of underlying dynamic systems.However,this method often relies on manual inspection due to uncertainties from iden-tifying the scaling region,making the correlation dimension value calculation troublesome and subjective.Therefore,it is necessary to propose a fast and intelligent algorithm to solve the above problem.This study implies the distinct windows tracking technique and fuzzy C-means clustering algorithm to accu-rately identify the scaling range and estimate the correlation dimension values.The proposed method is verified using the classic Lorenz chaotic system and 10 streamflow series in the Daling River basin of Liaoning Province,China.The results reveal that the proposed method is an intelligent and robust method for rapidly and accurately calculating the correlation dimension values,and the average operation efficiency of the proposed algorithm is 30 times faster than that of the original Grassberger-Procaccia algorithm. 展开更多
关键词 chaotic time series correlation dimension distinct windows tracking fuzzy C-means clustering
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Parametric study to implement a water-weakening process in UDEC
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作者 Fengchang Bu Michel Jaboyedoff +3 位作者 Marc-Henri Derron Lei Xue Yuan Cui Chao Xu 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1378-1386,共9页
Despite the prevalence and validity of the universal distinct element code(UDEC)in simulations in geotechnics domain,water-weakening process of rock models remains elusive.Prior research has made positive contribution... Despite the prevalence and validity of the universal distinct element code(UDEC)in simulations in geotechnics domain,water-weakening process of rock models remains elusive.Prior research has made positive contributions to a presupposed link between modelling parameters and saturation degree,Sr.Nevertheless,this effort presents inaccurate results and limited implications owing to the misleading interpretation,that is,devoid of the basic logic in UDEC that modelling parameters should be calibrated by tested macroscopic properties in contrast to a presupposed relation with Sr.To fill this gap,a new methodology is proposed by coupling a computationally efficient parametric study with the simulation of water-weakening mechanisms.More specifically,tested macroscopic properties with different Sr values are input into parametric relations to acquire initial modelling parameters that are sequentially calibrated and modulated until simulations are in line with geomechanical tests.Illustrative example reveals that numerical water-weakening effects on macroscopic properties,mechanical behaviours,and failure configurations are highly consistent with tested ones with noticeable computational expediency,implying the feasibility and simplicity of this methodology.Furthermore,with compatibility across various numerical models,the proposed methodology substantially extends the applicability of UDEC in simulating water-weakening geotechnical problems. 展开更多
关键词 Parametric analysis Universal distinct element code(UDEC) Water-weakening Rock strength
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Qinghai Quartet:Ecological Poem Composed of Salt Lake,Danxia Landscape,Aiken Spring,and Elves of Grassland
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作者 Bi Ran(Text/Photos) 《China's Tibet》 2025年第4期66-69,共4页
Editor’s Note:On the northeastern edge of the Qinghai-Xizang Plateau,Qinghai weaves a dynamic ecological symphony composed of four distinct natural languages.Here,one can find not only solidified waves-represented by... Editor’s Note:On the northeastern edge of the Qinghai-Xizang Plateau,Qinghai weaves a dynamic ecological symphony composed of four distinct natural languages.Here,one can find not only solidified waves-represented by the crystal-clear Qarhan Salt Lake-but also flowing flames-the passionate hues of the Guide Danxia landscape. 展开更多
关键词 qarhan salt lake Qinghai Plateau guide danxia landscape Salt Lake Danxia Landscapes ecological symphony four distinct natural languageshereone flowing flames
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采动影响下山区地表裂隙发育通用离散单元法模拟研究 被引量:4
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作者 张明清 桂庆军 范少华 《科学技术与工程》 北大核心 2014年第22期14-16,22,共4页
贵州响水煤矿3#煤层12309回采工作面停采后,离工作面较近地表未发现裂隙,远离工作面地表反而出现明显裂隙,针对这一现象,运用UDEC软件对12309采面进行了仿真数值模拟实验,通过模拟实验得到:采深172 m的开切眼前后出现两组裂隙,裂隙呈&qu... 贵州响水煤矿3#煤层12309回采工作面停采后,离工作面较近地表未发现裂隙,远离工作面地表反而出现明显裂隙,针对这一现象,运用UDEC软件对12309采面进行了仿真数值模拟实验,通过模拟实验得到:采深172 m的开切眼前后出现两组裂隙,裂隙呈"V"字形;停采线处,水平离层裂隙和竖向破断裂隙贯通至地表冲沟;变坡面裂隙发育,稳定性差,会发生滑坡。 展开更多
关键词 煤矿 裂隙 山区 通用离散单元法(universal DISTINCT ELEMENT code UDEC)软件
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Freeliving marine nematodes as a pollution indicator of the Bohai Sea 被引量:9
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作者 GUOYu-qing R.M.Warwick +1 位作者 ZHANGZhi-nan MUFang-hong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2002年第4期558-562,共5页
A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes... A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and unpolluted. 展开更多
关键词 taxonomic distinctness index Δ + freeliving marine nematodes the Bohai Sea
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Responses of diff erent biodiversity indices to subsampling efforts in lotic macroinvertebrate assemblages 被引量:1
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作者 WANG Jun LI Zhengfei +3 位作者 SONG Zhuoyan ZHANG Yun JIANG Xiaoming XIE Zhicai 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第1期122-133,共12页
As a less time-consuming procedure, subsampling technology has been widely used in biological monitoring and assessment programs. It is clear that subsampling counts af fect the value of traditional biodiversity indic... As a less time-consuming procedure, subsampling technology has been widely used in biological monitoring and assessment programs. It is clear that subsampling counts af fect the value of traditional biodiversity indices, but its ef fect on taxonomic distinctness(TD) indices is less well studied. Here, we examined the responses of traditional(species richness, Shannon-Wiener diversity) and TD(average taxonomic distinctness: Δ +, and variation in taxonomic distinctness: Λ +) indices to subsample counts using a random subsampling procedure from 50 to 400 individuals, based on macroinvertebrate datasets from three dif ferent river systems in China. At regional scale, taxa richness asymptotically increased with ?xed-count size; ≥250–300 individuals to express 95% information of the raw data. In contrast, TD indices were less sensitive to the subsampling procedure. At local scale, TD indices were more stable and had less deviation than species richness and Shannon-Wiener index, even at low subsample counts, with ≥100 individuals needed to estimate 95% of the information of the actual Δ + and Λ + in the three river basins. We also found that abundance had a certain ef fect on diversity indices during the subsampling procedure, with dif ferent subsampling counts for species richness and TD indices varying by regions. Therefore, we suggest that TD indices are suitable for biodiversity assessment and environment monitoring. Meanwhile, pilot analyses are necessary when to determine the appropriate subsample counts for bioassessment in a new region or habitat type. 展开更多
关键词 SUBSAMPLING MACROINVERTEBRATES TAXONOMIC distinctness indices TAXA richness Shannon-Wiener index
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Morphological and molecular diversity of arbuscular mycorrhizal fungi in revegetated iron-mining site has the same magnitude of adjacent pristine ecosystems 被引量:1
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作者 Caroline Krug Vieira Matheus Nicoletti Marascalchi +2 位作者 Arthur Vinicius Rodrigues Rafael Dutra de Armas Sidney Luiz Stürmer 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第5期330-343,共14页
Arbuscular mycorrhizal fungi(AMF) are important during revegetation of mining sites, but few studies compared AMF community in revegetated sites with pristine adjacent ecosystems. The aim of this study was to assess... Arbuscular mycorrhizal fungi(AMF) are important during revegetation of mining sites, but few studies compared AMF community in revegetated sites with pristine adjacent ecosystems. The aim of this study was to assess AMF species richness in a revegetated iron-mining site and adjacent ecosystems and to relate AMF occurrence to soil chemical parameters. Soil samples were collected in dry and rainy seasons in a revegetated iron-mining site(RA) and compared with pristine ecosystems of forest(FL), canga(NG),and Cerrado(CE). AMF species were identified by spore morphology from field and trap cultures and by LSU r DNA sequencing using Illumina. A total of 62 AMF species were recovered, pertaining to 18 genera and nine families of Glomeromycota. The largest number of species and families were detected in RA, and Acaulospora mellea and Glomus sp1 were the most frequent species. Species belonging to Glomeraceae and Acaulosporaceae accounted for 42%–48% of total species richness. Total number of spores and mycorrhizal inoculum potential tended to be higher in the dry than in the rainy season, except in RA. Sequences of uncultured Glomerales were dominant in all sites and seasons and five species were detected exclusively by DNA-based identification. Redundancy analysis evidenced soil p H,organic matter, aluminum, and iron as main factors influencing AMF presence. In conclusion, revegetation of the iron-mining site seems to be effective in maintaining a diverse AMF community and different approaches are complementary to reveal AMF species, despite the larger number of species being identified by traditional identification of field spores. 展开更多
关键词 Community structure GLOMEROMYCOTA ILLUMINA LSU rDNA Spore morphology Taxonomic distinctness index
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