期刊文献+
共找到187篇文章
< 1 2 10 >
每页显示 20 50 100
Prioritization of erosion prone sub-watersheds using morphometric analysis and RUSLE-based approaches:A case of Hare Watershed,Abaya Chamo Sub-basin,Ethiopia
1
作者 Tegegn Takele MANA Samuel Dagalo HATIYE 《Journal of Mountain Science》 2025年第2期537-555,共19页
Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model tec... Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model techniques to quantify soil erosion and thereby prioritize impacted areas.This work used an automated GIS-based tool(SWPT)to prioritize crucial areas based on topohydrological and morphometric factors and predict soil loss in sub-watersheds using the RUSLE model.Land use/cover data were obtained from Landsat imagery,while slope and morphometric information were extracted from digital elevation data with a resolution of 12.5 m.Soil erodibility was determined using Ethiopian soil maps,and rainfall erosivity was computed using meteorological data.An average annual soil loss of 49 t ha-1 yr-1 was observed in the Hare watershed.Sub-watershed 11 was found to be the most affected,with an average annual soil loss of 85.12 t ha-1 yr-1and a compound parameter value(CPV)of 0.059.Subwatershed 17 has the least amount of soil loss,with 3.67t ha-1 yr-1 and a CPV of 1.32.The study emphasizes the usefulness of integrating RUSLE and morphometric analysis for soil and water conservation planning,suggesting a variety of modeling tools in data-sparse locations to quantify and prioritize erosion-prone areas. 展开更多
关键词 Erosion prioritization GIS-based tool(SWPT) Hare watershed Land degradation morphometric analysis RUSLE model
原文传递
Diversity and Morphometrics of Palm Weevils of the Genus Rhynchophorus in Maniema Province, Democratic Republic of Congo
2
作者 Angundji Yumbi Chérif Muhigwa Bahananga Jean-Berckmans +2 位作者 Manga Tshomba Joseph Dieudonné Cikwanine Murhabale Cisirika Bertin 《Advances in Entomology》 2025年第1期152-173,共22页
An inventory of Rhynchophorus species was carried out to determine their diversity, biogeographical variability and morphometrics. A shotgun trapping method was used at nine sites in three districts over a four-month ... An inventory of Rhynchophorus species was carried out to determine their diversity, biogeographical variability and morphometrics. A shotgun trapping method was used at nine sites in three districts over a four-month period, identifying three species: R. quadrangulus, R. phoenicis, R. ferrugineus and a probable variant of R. phoenicis. Of these species, R. phoenicis stands out as the most widespread palm weevil, while the probable variant of R. phoenicis is considered the rarest subspecies in the Maniema region. The color of the head and elytra is a criterion for distinguishing the different species of Rhynchophorus spp. Morphological criteria indicate that the probable subspecies of R. phoenicis is the largest palm weevil in the Maniema region and even globally. It is followed by R. quadrangulus and, by far, by R. phoenicis. The smallest palm weevil in Maniema is R. ferrugineus. Moreover, these criteria reveal that, for all three species identified, the female is generally larger than the male. This study has the merit of extending the distribution of R. ferrugineus from the Maghreb to the central East of the DRC, and highlighting a subspecies of R. phoenicis. Recognition of the sexes on the basis of the shape of the tip of the abdomen (oval in the male and flat in the female) is an additional contribution. 展开更多
关键词 INVENTORY DIVERSITY morphometricS Palm Weevils
在线阅读 下载PDF
Sub-Watershed Prioritization of Chambal River Basin Using Morphometric and Topo-Hydrological Parameters
3
作者 Teja Ram Nitharwal Vipin Chandra Lal +4 位作者 Arun Pratap Mishra Kaushalendra Kumar Karvendu Rashmi Singh Geeta Kumari Ashvini Kumar 《Journal of Environmental & Earth Sciences》 2025年第5期117-129,共13页
Natural resource management is essential to sustain human well-being and the environment.Water and soil are two of the most important natural resources that require careful management.The western part of India faces m... Natural resource management is essential to sustain human well-being and the environment.Water and soil are two of the most important natural resources that require careful management.The western part of India faces multiple challenges,including climatic variability,soil degradation,water scarcity,deforestation,etc.The basin’s sub-watersheds are delineated and prioritised using the Soil and Water Assessment Tool(SWAT)and Sub Watershed Prioritization Tool(SWPT),respectively,using morphometric and topo-hydrological characteristics,and the sub-watersheds are further ranked using Weighted Sum Analysis(WSA).The findings indicate that SWS19,SWS18,SWS1,SWS17,SWS16,and SWS15,which are drained by the rivers Chambal,Kali Sindh,Mashi,Parbati,Parwan,and Beradi,are highly vulnerable sub-watersheds.By integrating remote sensing,GIS techniques,and quantitative morphometric analysis,parameters such as drainage density,stream frequency,bifurcation ratio,and slope gradient were evaluated.The analysis revealed critical sub-watersheds characterized by steep slopes,high drainage density,and poor vegetation cover,indicating their susceptibility to erosion and runoff.The findings underscore the necessity for targeted soil conservation measures,such as contour bunding,afforestation,and water retention structures.This study highlights the utility of geospatial tools for sustainable watershed management and provides a replicable framework for prioritizing sub-watersheds in similar regions. 展开更多
关键词 morphometric Analysis Topo-Hydrology Sub-Watershed Prioritization Tool(SWPT) Natural Resource Management Soil and Water Weighted Sum Analysis(WSA) Chambal River Basin
在线阅读 下载PDF
Kinematic and morphometric evidence for recent reactivation of the Kale-Yeşilyurt fault zone within the East Anatolian Fault System 被引量:1
4
作者 Elif AKGÜN 《Journal of Mountain Science》 SCIE CSCD 2024年第12期4149-4176,共28页
The Kale-Yeşilyurt Fault Zone(KYFZ)exhibits recent tectonic reactivation,which is critical for understanding regional seismicity and the geodynamic evolution of the East Anatolian Fault System(EAFS).This study integra... The Kale-Yeşilyurt Fault Zone(KYFZ)exhibits recent tectonic reactivation,which is critical for understanding regional seismicity and the geodynamic evolution of the East Anatolian Fault System(EAFS).This study integrates kinematic and morphometric analyses to explore the reactivation processes along the fault.Kinematic analysis,incorporating fault-slip data and stress inversion,reveals complex deformation patterns characterized by strike-slip and extensional movements,with NE-SW trending minimum stress axes.February 6,2023,earthquake sequence highlighted significant stress accumulation along the Kale-Yeşilyurt and Göksun segments.Fieldwork and morphometric analyses,including mountain front sinuosity(Smf)and drainage basin analysis,suggest variable uplift rates and tectonic forces,with an asymmetric westward-directed uplift along the KYFZ.HI-HC index analysis underscores rapid uplift,particularly in the western basin,signaling ongoing tectonic and geomorphic activity.The normalized channel steepness index(Ksn)values reveal variations in erosion rates,providing insight into regional uplift patterns and knickpoint distribution.While morphometric indicators collectively point to high tectonic activity along the Yeşilyurt segment,the Kale segment exhibits particularly intense activity with a dominant normal fault component.The 2020 Sivrice earthquake and the 2023 earthquake doublet further emphasize the structural complexity of the fault system and underscore the KYFZ’s pivotal role in the active tectonics of the EAFS.Future research incorporating advanced geospatial technologies is vital for improving our understanding of tectonic processes,mitigating earthquake hazards,and enhancing seismic risk assessments. 展开更多
关键词 Kinematic analyses morphometric analyses Kale-Yeşilyurt Fault Zone(KYFZ) East Anatolian Fault System(EAFS)
原文传递
Normal sperm head morphometric reference values in fertile Asian males 被引量:1
5
作者 Ye-Lin Jia Ying-Bi Wu +6 位作者 Lin Yu Yan Zheng Ting-Ting Yang Yan-Yun Wang Bin Zhou Lin Zhang Fu-Ping Li 《Asian Journal of Andrology》 SCIE CAS CSCD 2024年第3期315-320,共6页
Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential.Severalcriteria are available to analyze sperm head morphology,but they are limited by poor methodol... Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential.Severalcriteria are available to analyze sperm head morphology,but they are limited by poor methodology comparability and populationapplicability.This study aimed to explore comprehensive and new normal morphometric reference values for spermatozoa heads infertile Asian males.An automated sperm morphology analysis system captured 23152 stained spermatozoa from confirmed fertilemales.Of these samples,1856 sperm head images were annotated by three experienced laboratory technicians as“normal”.Weemployed 14 novel morphometric features to describe sperm head size(head length,head width,length/width ratio,and girth),shape(ellipse intersection over union,girth intersection over union,short-axis symmetry,and long-axis symmetry),area(head,acrosome,postacrosomal areas,and acrosome area ratio),and degrees of acrosome and nuclear uniformity.This straight-forwardmethod for the morphometric analysis of sperm by accurate visual measurements is clinically applicable.The measured parameterspresent valuable information to establish morphometric reference intervals for normal sperm heads in fertile Asian males.Thepresented detailed measurement data will be valuable for interlaboratory comparisons and technician training.In vitro fertilizationand andrology laboratory technicians can use these parameters to perform objective morphology evaluation when assessing malefertilization potential. 展开更多
关键词 fertile Asian males head morphometric reference value normal spermatozoa
原文传递
Morphometric analysis and watershed delineation of the Karnaphuli river basin:A comparative study using different DEMs in Chittagong,Bangladesh 被引量:1
6
作者 Sujit Kumar Roy Md.Arif Chowdhury 《River》 2024年第4期426-437,共12页
The present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed,Bangladesh,using different digital elevation models(DEMs).Two DEMs,the shuttle radar... The present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed,Bangladesh,using different digital elevation models(DEMs).Two DEMs,the shuttle radar topographic mission(SRTM)and the terra advanced spaceborne thermal emission and reflection radiometer(ASTER),were employed to delineate watershed boundaries and evaluate various morphometric characteristics.Raster data such as fill sinks,flow direction,and flow accumulation were utilized to delineate the watershed.The morphometric analysis included the estimation of linear,areal,and relief parameters.The findings revealed a noticeable difference between the datasets;ASTER delineated a larger watershed area than SRTM.Regarding stream order,there were streams ranging from 1st to 6th order,encompassing numerous small,medium,and main channels of the river.Drainage density was calculated as 0.52 km/km^(2)for SRTM and 0.51 km/km^(2)for ASTER,both having a spatial resolution of 30m.The bifurcation ratio ranged from 1.94 for SRTM to 2.45 for ASTER,indicating varying degrees of structural disturbance influenced by geological factors.The form factor indicated an elongated shape of the study area.The overall dimensions of the streams and the watershed extent suggest moderate mean annual rainfall discharge.The watershed exhibited relatively high denudation rates,attributed to the basin relief.A low drainage density indicated the importance of infiltration processes.The findings of this study provide valuable insights into the spatial variability of watershed characteristics,highlighting the need for tailored management strategies for the Karnaphuli River.Implementing targeted conservation measures and watershed management practices based on these morphometric parameters can enhance water resource sustainability and ecological health in the region. 展开更多
关键词 ASTER DEM Drainage network Karnaphuli river morphometric analysis SRTM Watershed
在线阅读 下载PDF
Intraspecific leaf morphological variation in Quercus dentata Thunb.:a comparison of traditional and geometric morphometric methods,a pilot study 被引量:1
7
作者 Kaiyu Yang Jianghao Wu +4 位作者 Xinman Li Xinbo Pang Yangchen Yuan Guohui Qi Minsheng Yang 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第6期1751-1764,共14页
To compare the application of traditional morphometric methods(TMMs)and geometric morphometric methods(GMMs)in the study of intraspecific leaf morphological characters of Quercus dentata,fifteen linear measurement ind... To compare the application of traditional morphometric methods(TMMs)and geometric morphometric methods(GMMs)in the study of intraspecific leaf morphological characters of Quercus dentata,fifteen linear measurement indices and thirteen landmarks of leaves were used to study leaf morphology of three provenances(H1,H2,and H3).In TMMs,principal component analysis(PCA)showed that leaf size–related indices played an important role in population classification.Partial least square(PLS)analysis showed that the main morphological characters affecting leaf size were the average depth of the lobes and the length–width ratios.However,the important indices to distinguish the provenances were circularity,leaf width,and length–width ratio.The results of discriminant analysis(DA)showed that 74.0%of H1,68.0%of H2,and 74.0%of H3 were correctly classified.Cluster analysis showed that the Mahalanobis distances between H1 and H2,H1 and H3,and H2 and H3 were 4.3761,11.4629,and 10.2067,respectively.In GMMs,PCA based on symmetrical components showed that the difference in leaf morphology was mainly due to the changing trend of the leaf apex and base,petiole length,and degree of leaf cracking.PLS analysis showed that there was a significant covariation between the leaf symmetrical components and size:as the leaf enlarged,the widest part gradually moved up,and the shape changed from nearly oval to lanceolate.DA results showed that 86.0%and 78.0%of H1 and H2,70.0%and 80.0%of H1 and H3,and 82.0%and 76.0%of H2 and H3 were correctly classified.Canonical variate analysis results showed that the Mahalanobis distances between H1 and H2,H1 and H3,and H2 and H3 were 1.7238,1.5380,and 1.6329,respectively.Both GMMs and TMMs showed significant differences in morphology among the three Q.dentata provenances,but GMMs had higher classification accuracy and could provide more information about leaf shape,whereas TMMs could provide more information about leaf size.Based on our results,GMMs are promising in the study of leaf morphological variation within Q.dentata provenances. 展开更多
关键词 Traditional morphometrics Geometric morphometrics Leaf morphology variation Quercus dentata INTRASPECIFIC
在线阅读 下载PDF
Morphometrics analysis on the hind wing of Tetrigides(Orthoptera) and its application in taxonomy 被引量:1
8
作者 张荣娇 周善义 邓维安 《Entomotaxonomia》 CSCD 2016年第3期175-183,共9页
The morphological characteristics of the hind wing venation of tetrigids were analyzed on the basis of morphometric measurement, with 20 species and 18 different variables selected for this study. Results show that th... The morphological characteristics of the hind wing venation of tetrigids were analyzed on the basis of morphometric measurement, with 20 species and 18 different variables selected for this study. Results show that three principal components have a higher load at the length between the starting point of the costal vein and the tip of the fourth anal vein, between the tip of the costal vein and the tip of the third anal vein, and between the tip of the costal vein and the tip of the eleventh anal vein. There exists a contrast between wing length and width. 展开更多
关键词 morphometric measurement insect morphology evolutionary development
原文传递
The levels of serum fibrosis marks and morphometric quantitative measurement of hepatic fibrosis 被引量:13
9
作者 Shi-Bin Xie Ji-Lu Yao +2 位作者 Shu-Sen Zheng Chun-Lan Yao Rong-Qin Zheng From the Department of Infectious Diseases, Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2002年第2期202-206,共5页
Objective: To study the relationship between the ser- um levels of hyaluronic acid (HA), procollagen type Ⅲ (PCⅢ), collagen type Ⅳ (CIV) and the histologi- cal degree of hepatic fibrosis evaluated by image analysis... Objective: To study the relationship between the ser- um levels of hyaluronic acid (HA), procollagen type Ⅲ (PCⅢ), collagen type Ⅳ (CIV) and the histologi- cal degree of hepatic fibrosis evaluated by image analysis, and the clinical significance of serum HA, PC Ⅲ, C Ⅳ in the diagnosis of hepatic fibrosis in pa- tients with chronic viral hepatitis. Methods: The concentrations of serum HA, PC Ⅲ, C Ⅳ in 151 patients with chronic viral hepatitis were measured by radioimmunoassay. Liver biopsies were performed in all the patients. Histological sections of 4 μm thickness were stained with Masson's trichrome for fibrosis assessment. Morphometric quantitative measurements for hepatic fibrosis assessment in the 4 μm sections were performed using a fully automated image analysis system. Serum levels of HA, PC Ⅲ, and C Ⅳ were analyzed at different stages of liver pa- thology and compared with the morphometric quanti- tative measurements of hepatic fibrosis. Results: The serum levels of HA, PC Ⅲ, C Ⅳ all ele- vated gradually with the progression of the disease, and all reached the highest in patients with liver cir- rhosis. There was a significant difference in the levels of these 3 components between liver cirrhosis group and the other groups (P<0.05). They all increased steadily with the histological stages of hepatic fibrosis, and reached the highest levels in stage Ⅳ. The serum levels of HA, PC Ⅲ, C Ⅳ were all positive- ly correlated with the histological stages of liver sec- tions and the morphometric measurement (P< 0.001). The coefficients with stages were 0.694, 0.493, 0.552 (P<0.001), respectively and with sur- face density of total collagen on liver biopsy sections by image analysis were 0. 715, 0. 595, 0. 573 (P< 0.001), respectively. Conclusion: The serum levels of HA, PC Ⅲ, C Ⅳ were in consistent with the degree of hepatic fibrosis, and the determination of these marks is valuable for detecting hepatic fibrosis. 展开更多
关键词 hyaluronic acid procollagen type collagen type hepatic fibrosis morphometric measurement
暂未订购
Morphometric discrimination of wild from farmed Dybowski’s frog (Rana dybowskii) based on hindlimb length 被引量:5
10
作者 XIA Rui HUANG Xiao-ming +3 位作者 YANG Shu-hui XU Yan-chun Ying Lu Thomas D. Dahmer 《Journal of Forestry Research》 SCIE CAS CSCD 2011年第2期269-274,共6页
Commercial farming of anuran species that are declining in the wild raises a need to discriminate wild from farmed frogs.We hypothesized wild frogs might have extended hindlimbs due to greater frequency or intensity o... Commercial farming of anuran species that are declining in the wild raises a need to discriminate wild from farmed frogs.We hypothesized wild frogs might have extended hindlimbs due to greater frequency or intensity of jumping relative to farmed frogs,highlighting a morphometric approach to discrimination of wild from farmed frogs using hindlimb length.In the present study,Dybowski's frog(Rana dybowskii) was used to test this hypothesis.We measured body mass(Mb) and hindlimb length(Lh) of 2-year old farmed frogs and wild frogs aged 2 to 5 years.Dybowski's frog demonstrated significant dimorphism in Mb and Lh.Mb was significantly greater among farmed 2-year old frogs in both sexes(p=0.000),while only among females was Lh significantly greater for wild frogs(p=0.000).Lh/Mb was used as an index for origin discrimination to eliminate the influence of Mb due to variation of husbandry conditions among farms.Mean Lh/Mb for farmed frogs was significantly lower than for wild frogs(p=0.000) in the 2-year old age class.Discrimination correctly classified 84.4% of farmed and 96.3% of wild male frogs.Among females,92.9% of farmed frogs and 90.1% wild frogs were correctly classified.The overall correctness of classification was 92.1% and 90.8% for males and females,respectively.However,Lh/Mb revealed variation with age,resulting in reduced discriminative power for frogs ≥3 years old.We introduced a coefficient Ce to adjust the Lh/Mb of frogs ≥3 years to the level equivalent to 2-year frogs.The adjustment achieved 89.5% for overall correctness of origin for wild males and 92.4% for wild females ≥3 years old.These results show that Lh/Mb is an effective index to discriminate wild from farmed Dybowski's frog.Since the physical demands of jumping are common among anurans,this index is also potentially applicable to other anuran species. 展开更多
关键词 Dybowski's frog morphometric discrimination WILD FARMED Rana dybowskii
在线阅读 下载PDF
Morphometrics:History,development methods and prospects 被引量:6
11
作者 Norman MacLeod 《Zoological Systematics》 CSCD 2017年第1期4-33,共30页
Morphometrics has been pursued by graphical and computational means since the European Renaissance, drawing on core geometric principles first discovered in China and Classical Greece. Through the late 1800s, two dist... Morphometrics has been pursued by graphical and computational means since the European Renaissance, drawing on core geometric principles first discovered in China and Classical Greece. Through the late 1800s, two distinct approaches to such analyses were pursued: a deformationist approach, epitomized by D'Arcy Thompson's graphical trans-formation grids and the statistical approach popularized by Francis Galton, Karl Pearson, and Julian Huxley in which Cartesian spaces were employed to summarize patterns of variation in size and/or shape variables. Unification of these approaches was an off-stated goal throughout the 20th century, but proved elusive until the mid-1980s when David Kendall, Fred Bookstein, and Colin Goodall proposed a radically new way of understanding form -- as the locations of configurations of landmarks on the surfaces of a nested series of hyperdimensional manifolds. Once this new mathematics of form was understood development of basic concepts, procedures, graphical tools, and statistical tests followed quickly such that the core of the long-hoped for synthesis took less than a decade to achieve. The result-- geometric morphometrics -- continues to develop into an ever-more extensive toolkit that can be used by researchers to describe and understand a wide range of problems involving the characterization of morphological similarities and differences in all of their many and varied contexts. In particular, the new approaches involving the direct analysis of image pixels and new tools such as machine learning and artificial intelligence are set to reinvigorate (and possibly to revolutionize) the field once again. 展开更多
关键词 morphometricS FORM size SHAPE biology geometry.
原文传递
Geometric morphometric analysis of Eysarcoris guttiger,E.annamita and E.ventralis(Hemiptera:Pentatomidae) 被引量:7
12
作者 Rongrong Li Hufang Zhang +1 位作者 Shengcai Li Ming Bai 《Zoological Systematics》 CSCD 2017年第1期90-101,共12页
The genus Eysarcoris can be easily distinguished from other genera through the two spots in the basal angle of the scutellum. Nevertheless, Eysarcoris species show complex variances. Geometric morphometric methods hav... The genus Eysarcoris can be easily distinguished from other genera through the two spots in the basal angle of the scutellum. Nevertheless, Eysarcoris species show complex variances. Geometric morphometric methods have been increasingly applied to distinguish species and to define the boundary of genera among insects. In the present study, geometric morphometric approach was firstly employed to evaluate the shape variation of three characters (fore wing, hind wing and pygophore) of E. guttiger, E. annamita and E. ventralis using E. aeneus as outgroup to ascertain whether this approach is a reliable method for the taxonomy of Eysarcoris. Analysis was conducted on the landmarks of the three characters of these species. Multivariate regression of procrustes coordinates against centroid size was conducted to test the presence of allometry. Principal component analysis (PCA), canonical variate analysis (CVA) and cluster analysis were utilized to describe variations in shapes among the studied species. For all of the three characters, though PCA analysis showed some overlap among species, p-values for procrustes distance and mahalanobis distance were all less than 0.0001. The distribution of the three studied species corresponds with their species status. This study demonstrates that the geometric morphometrics of both the fore wing and the hind wing might represent a possible tool for the identification of species within this genus. 展开更多
关键词 Geometric morphometrics principal component analysis canonical variateanalysis cluster analysis.
原文传递
Prioritization of Semi-Arid Agricultural Watershed Using Morphometric and Principal Component Analysis, Remote Sensing, and GIS Techniques, the Zerqa River Watershed, Northern Jordan 被引量:7
13
作者 Yahya Farhan Ali Anbar +1 位作者 Nisrin Al-Shaikh Rami Mousa 《Agricultural Sciences》 2017年第1期113-148,共36页
Remote sensing and GIS techniques were employed for prioritization of the Zerqa River watershed. Forty-three 4th order sub-watersheds were prioritized based on morphometric and Principal Component Analysis (PCA), in o... Remote sensing and GIS techniques were employed for prioritization of the Zerqa River watershed. Forty-three 4th order sub-watersheds were prioritized based on morphometric and Principal Component Analysis (PCA), in order to examine the effectiveness of morphometric parameters in watershed prioritization. A comparison has been carried out between the results achieved through applying the two methods of analysis (morphometric and PCA). Afterwards, suitable measures are proposed for soil and water conservation. Topo sheets and ASTER DEM have been employed to demarcate the 43 sub-watersheds, to extract the drainage networks, and to compile the required thematic maps such as slope categories and elevation. LANDSAT 8 image (April-2015) is employed to generate land use/cover maps using ENVI (v 5.1) software. The soil map of the watershed has been digitized using Arc GIS software. Prioritization of the 43 sub-watersheds was performed using ten linear and shape parameters, and three parameters which are highly correlated with components 1 and 2. Subsequently, different sub-watersheds were prioritized by ascribing ranks based on the calculated compound parameters (Cp) using the two approaches. Comparison of the results revealed that prioritization of watersheds based on morphometric analysis is more consistent and serves for better decision making in conservation planning as compared with the PCA approach. The recommended soil conservation measures are prescribed in accordance with the specified priority, in order to avoid undesirable effects on land and environment. Sub-watersheds classified under high priority class are subjected to high erosion risk, thus, creating an urgent need for applying soil and water conservation measures. It is expected that decision makers will pay sufficient attention to the present results/information, activate programs encouraging soil conservation, integrated watershed management, and will continue working on the afforestation of the government-owned sloping lands. Such a viable approach can be applied at different parts of the rainfed highland areas to minimize soil erosion loss, and to increase infiltration and soil moisture in the soil profile, thus, reducing the impact of recurrent droughts and the possibility of flooding hazards. 展开更多
关键词 PRIORITIZATION morphometric ANALYSIS Principal Component ANALYSIS Soil Conservation Land Use/Cover GIS
暂未订购
Cranial variation in allactagine jerboas(Allactaginae,Dipodidae, Rodentia): a geometric morphometric study 被引量:3
14
作者 Bader H.Alhajeri 《Zoological Research》 SCIE CAS CSCD 2021年第2期182-194,共13页
Allactaginae is a subfamily of dipodids consisting of four-and five-toed jerboas(Allactaga, Allactodipus,Orientallactaga, Pygeretmus, Scarturus) found in open habitats of Asia and North Africa. Recent molecular phylog... Allactaginae is a subfamily of dipodids consisting of four-and five-toed jerboas(Allactaga, Allactodipus,Orientallactaga, Pygeretmus, Scarturus) found in open habitats of Asia and North Africa. Recent molecular phylogenies have upended our understanding of this group's systematics across taxonomic scales. Here, I used cranial geometric morphometrics to examine variation across 219 specimens of 14 allactagine species(Allactaga major, A. severtzovi, Orientallactaga balikunica, O.bullata, O. sibirica, Pygeretmus platyurus, P. pumilio,P. shitkovi, Scarturus aralychensis, S. euphraticus,S. hotsoni, S. indicus, S. tetradactylus, S. williamsi)in light of their revised taxonomy. Results showed no significant sexual size or shape dimorphism. Species significantly differed in cranial size and shape both overall and as species pairs. Species identity had a strong effect on both cranial size and shape. Only a small part of cranial shape variation was allometric,with no evidence of unique species allometries, and most specimens fit closely to the common allometric regression vector. Allactaga was the largest,followed by Orientallactaga, Scarturus, and finally Pygeretmus. Principal component 1(PC1) separated O. bullata+O. balikunica+S. hotsoni(with inflated bullae along with reduced zygomatic arches and rostra) from A. major+A. severtzovi+O. sibirica(with converse patterns), while PC2 differentiated Orientallactaga(with enlarged cranial bases and rostra along with reduced zygomatic arches and foramina magna) from Scarturus+Pygeretmus(with the opposite patterns). Clustering based on the unweighted pair group method with arithmetic mean(UPGMA) contained the four genera, but S. hotsoni clustered with O. bullata+O. balikunica and O.sibirica clustered with A. major+A. severtzovi, likely due to convergence and allometry, respectively. 展开更多
关键词 Allactaga Cranial morphometrics Five-toed jerboas Orientallactaga Pygeretmus Scarturus
在线阅读 下载PDF
Geometric morphometrics:Current and future in China 被引量:3
15
作者 Ming Bai 《Zoological Systematics》 CSCD 2017年第1期1-3,共3页
Although there were many ancient Chinese mathematicians contributed a lot on geometry, Geometric morphometrics (GM) in modern concept was not firstly proposed by Chinese. The super capability of geometric morphometr... Although there were many ancient Chinese mathematicians contributed a lot on geometry, Geometric morphometrics (GM) in modern concept was not firstly proposed by Chinese. The super capability of geometric morphometries in scientific computing and problem solving has gained a lot of attentions in the world. Until early of 21 centuries, geometric morphometries was introduced into China. Since then, GM was rapidly applied in many research fields. However, it is a pity that GM is still not well-known in China as many works are published out of China. Thus, the special issue "Geometric morphometrics: Current shape and future directions" is organized. The present issue presents a series of contributions in this scientific field. In future, there will be many considerable new developing fields on GM needed to pay more attentions, for instances, 3D geometric morphometrics, 4D analysis, visualization of amber, new machine developing, new software developing, automatic identification system, etc. Once these technical bottle-necks on 3D data collecting and merging geometric morphometric data from multiple characters could be solved, the automatic identification system and other fields based on Big Data would come true. 展开更多
关键词 Geometric morphometrics 3D LED-SIM VISUALIZATION multiple characters.
原文传递
Current status and potential of morphometric sperm analysis 被引量:2
16
作者 Alejandro Maroto-Morales Olga Garcia-Alvarez +4 位作者 Manuel Ramon Felipe Martinez-Pastor M Rocio Fernandez-Santos A Josefa Soler Jose Julian Garde 《Asian Journal of Andrology》 SCIE CAS CSCD 2016年第6期863-870,共8页
The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different... The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cryoresistance and male fertility is also discussed. For this, the evaluation of patterns of change of sperm head morphometry throughout a process, instead of the study of the morphometric characteristics of the sperm head at different stages, allows a better identification of the males with different sperm cryoconservation ability. These new approaches, together with more studies employing a greater number of individuals, are needed to obtain novel results concerning the role of sperm morphometry on sperm function. Future studies should aim at understanding the causes of sperm design diversity and the mechanisms that generate them, giving increased attention to other sperm structures besides the sperm head. The implementation of scientific and technological advances could benefit the simultaneous examination of sperm phenotype and sperm function, demonstrating that sperm morphometry could be a useful tool for sperm assessment. 展开更多
关键词 computer-assisted sperm morphometric analysis MAMMALS sperm function sperm morphometry
原文传递
Watershed Prioritization of Palar Sub-watershed Based on the Morphometric and Land Use Analysis 被引量:2
17
作者 Evangelin Ramani SUJATHA Radhakrishnan SELVAKUMAR Balasubramaniam RAJASIMMAN 《Journal of Mountain Science》 SCIE CSCD 2014年第4期906-916,共11页
Morphometric analysis is an indispensable tool for hydrological investigation that involves the development and management of drainage basin. This study characterizes the micro watersheds in the Palar sub-watershed us... Morphometric analysis is an indispensable tool for hydrological investigation that involves the development and management of drainage basin. This study characterizes the micro watersheds in the Palar sub-watershed using morphometric analysis and assesses its risk by land use and land cover features in a particular micro watershed. Palar sub-watershed is divided into 6 micro watersheds for prioritization based on morphometric and land use analysis. Several morphometric parameters (linear, shape and relief) are determined from the drainage map; ranks are assigned based on their capacity to induce erodability and degradation. Final ranking is based on the composite index calculated from the sum of the ranks of each morphometric parameter. Morphometric analysis reveals micro watersheds 5 and 6 as most susceptible and 2 and 3 as low susceptible. Land use is mapped using IRS ID LISS III satellite data. The risk in terms of watershed degradation involved to each micro watershed is based on the ranks of each land use feature, obtained from a similar composite index as that of morphometric analysis. Land use analysis shows that micro watersheds 2 and 4 fall under high priority category while 5 and 6 under low priority category. Integration of the morphometric and land use analysis shows that only microwatershed 1 falls under the same category in both analyses. Control measures are suggested to contain degradation depending on its specific land use pattern and morphometric features. This study ean be used to prepare a comprehensive watershed plan for the development or for planning resource conservation strategies, by integrating land use features with the drainage characteristics of the region, in particular for a hill ecosystem as the prioritization is at micro level. 展开更多
关键词 morphometric analysis Watersheddeterioration risk Land use Palar sub-watershed Kodaikkkanal
原文传递
Relation between basin morphometric features and dynamic characteristics of debris flows——a case study in Siberia, Russia 被引量:2
18
作者 Artem A.RYBCHENKO Alena V.KADETOVA Elena A.KOZIREVA 《Journal of Mountain Science》 SCIE CSCD 2018年第3期618-630,共13页
Extreme and prolonged rainfall in the Tunka Ridge caused several debris flows in the vicinity of the Arshan village(Siberia, Russia) on June 28, 2014. These debris flows, in spite of similar geological conditions, had... Extreme and prolonged rainfall in the Tunka Ridge caused several debris flows in the vicinity of the Arshan village(Siberia, Russia) on June 28, 2014. These debris flows, in spite of similar geological conditions, had different velocity, peak discharge and alluvial fan volume values. The flow velocity was from 3.5 m/s to 19.6 m/s, the peak discharge ranged from 63 m3/s to 13566 m3/s, and the alluvial fan volume varied from 4.13×103 to 8.45×105 m3. Such a great range of values is due to the morphometric parameters of the debris flow basins. The article deals with the influence of morphometric parameters of debris flow basins, such as the basin area, the average slope, Melton ratio, relief ratio on the debris flow velocity, peak discharge and volume of alluvial fans. In this debris flow event the average values of slope angle and total basin relief of the debris flow basins did not affect the values of debris flow velocity, peak discharge and alluvial fan volume. The highest correlations were observed with the debris flow basin area that was connected with the water inflow volume into the debris flow basins during the rainfall. The unequal water distribution among debris flow basins also had an impact on the debris flow velocity, peak discharge and volume of alluvial fans. 展开更多
关键词 Central Asia Debris flow morphometric analysis Natural Hazards Tunka Ridge
原文传递
Geomorphological analysis of the morphometric characteristics that determine the volume of sediment yield of Wadi AI-Arja, South Jordan 被引量:2
19
作者 Ali Hamdi ABU SALIM 《Journal of Geographical Sciences》 SCIE CSCD 2014年第3期457-474,共18页
This study addresses the morphometric variables that determine the sediment yield in Wadi AI-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sedi... This study addresses the morphometric variables that determine the sediment yield in Wadi AI-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its mor- phometric and hydrological characteristics. The study found several results, most notably: The classification of Wadi AI-Arja basin according to the hypsometric integral value (72.1%) within an uneven topography, which in- creases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield. The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi AI-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05. 展开更多
关键词 sediment yield Wadi AI-Arja morphometric characteristics: hypsometric integral JORDAN
原文传递
Three-dimensional Morphometric Analyses of Hominoid Lower Molars from Yuanmou in Yunnan Province,China 被引量:2
20
作者 Alan Walker 《人类学学报》 CSCD 北大核心 2002年第S1期1-13,共13页
Analysis of 3D measurements of 13 landmarks on 72 Yuanmou Hominoid lower molars and some comparative samples, using Euclidean Distance Matrix Analysis (EDMA), show that the 3D morphometric features of Yuanmou Homi noi... Analysis of 3D measurements of 13 landmarks on 72 Yuanmou Hominoid lower molars and some comparative samples, using Euclidean Distance Matrix Analysis (EDMA), show that the 3D morphometric features of Yuanmou Homi noid lower molars largely resemble those of Lufengpithecus. Compared with extant great apes and humans, both Yuanmou Hominoid and Lufengpithecus differ markedly from humans, whereas they show much resemblance to apes. The two Chinese hominoids and extant great apes are different from humans in many of the same ways. Moreover, 3D morphometric features of Yuanmou Hominoid lower molars differ from those of each of the three extant great apes in similar ways. Of the three, the orangutan is the closest match to Yuanmou Hominoid in tooth morphology. However, the exact implications of these similarities and differences remain to be determined. 展开更多
关键词 Yuanmou Hominoid Lufengpithecus morphometricS 3D analysis EDMA
在线阅读 下载PDF
上一页 1 2 10 下一页 到第
使用帮助 返回顶部