Geopotential, dynamic, orthometric and normal height systems and the corrections related to these systems are evaluated in this paper. Along two different routes, with a length of about 5 kilometers, precise leveling ...Geopotential, dynamic, orthometric and normal height systems and the corrections related to these systems are evaluated in this paper. Along two different routes, with a length of about 5 kilometers, precise leveling and gravity measurements are done. One of the routes is in an even field while the other is in a rough field. The magnitudes of orthometric, normal and dynamic corrections are calculated for each route. Orthometric, dynamic, and normal height differences are acquired by adding the corrections to the height differences obtained from geometric leveling. The magnitudes of the corrections between the two routes are compared. In addition, by subtracting orthometric, dynamic, and normal heights from geometric leveling, deviations of these heights from geometric leveling are counted.展开更多
It is a general knowledge that French as a language is widely spoken internationally whereas Urhobo is mainly spoken in the geographical location where it belongs. It is also spoken, and this, sparingly so, by Urhobo ...It is a general knowledge that French as a language is widely spoken internationally whereas Urhobo is mainly spoken in the geographical location where it belongs. It is also spoken, and this, sparingly so, by Urhobo persons in the Diaspora. Presently, Urhobo has become a language of study at the Delta State University, Abraka. It has also been included in the educational curriculum for study at the lower cadre of secondary school education in the Delta State. This situation has triggered the author＇s interest in doing a contrastive phonological study. The significance of this study is that it will highlight the salient differences in some of the grammatical aspects in the languages under consideration and also identify the difficulties that learners experience as a result of these difficulties. The author will also, as much as it is possible, proffer solutions to these learning difficulties.展开更多
The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new...The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new signs of vegetative and reproductive organs have been checked out and elaborated. It leads to the clarifying of new taxonomic status and geographical distribution of certain critical taxa. A set of species are threatened and need special measures which are included into the Red Data Book of Russian Federation. for their conservation. There are 13 species and one variety展开更多
The Chinese yew（Taxus wallichiana）,which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diver...The Chinese yew（Taxus wallichiana）,which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diversity within this species at the genetic and ecological levels,its genetic patterns and range dynamics must first be identified and mapped.This knowledge can then be applied in the development of an effective conservation strategy.Based on molecular data obtained from 48 populations of T.wallichiana,we used GIS-based interpolation approach for the explicit visualization of patterns of genetic divergence and diversity,and a number of potential evolutionary hotspots have been specifically identified within the genetic landscape maps.Within the maps of genetic divergence and diversity,five areas of high inter-population genetic divergence and six areas of high intra-population genetic diversity have been highlighted in a number of separate mountain regions,and these evolutionary hotspots should have the priority to be protected.Furthermore,four geographical barriers have been identified： the eastern Himalayas,the Yunnan Plateau,the Hengduan Mountains and the Taiwan Strait.According to ecological niche modeling（ENM）,the populations of T.wallichiana within the Sino-Himalayan Forest floristic subkingdom experienced westward expansion from the periods of Last Inter-glacial to Last Glacial Maximum（LGM）.Following the LGM,the distribution range overall became reduced and fragmented.These findings challenge the classic mode of contraction-expansion in response to the last glaciation.In conclusion,our findings suggest that the changes in geographical landscapes and climate that occurred during the Quaternary resulted in current genetic landscape patterns.展开更多
Contrasting multiple organisms with similar contemporary distributions, researchers can identify shared evolutionary patterns and provide historical context for community composition. We used three species complexes w...Contrasting multiple organisms with similar contemporary distributions, researchers can identify shared evolutionary patterns and provide historical context for community composition. We used three species complexes with overlapping distributions in Southeastern China and surrounding islands to explore the phylogeographic history of the region. Despite similar geographic distributions, genetic data revealed few congruent patterns, but all complexes displayed genetic divergence for Taiwan Residents populations. Additionally, niche modeling and divergence dating did not find support for diversification associated with the Last Glacial Maximum [Current Zoology 61 （5）： 943-950,2015].展开更多
As an essential component of proteins and genetic material for all organisms, nitrogen(N) is one of the major limiting factors that control the dynamics, biodiversity and functioning of lacustrine wetlands, in which i...As an essential component of proteins and genetic material for all organisms, nitrogen(N) is one of the major limiting factors that control the dynamics, biodiversity and functioning of lacustrine wetlands, in which intensified N biogeochemical activities take place. Reactive N loaded into wetland ecosystems has been doubled due to various human activities, including industrial, agricultural activities and urbanization. The main driving mechanisms of N transport and transformation in lacustrine wetlands are categorized to pushing forces and pulling forces in this study. Geomorphology, wetland age, N concentrations, and temperature are the main pushing forces(passive forces); whereas water table variation, oxygen concentration, other elements availability, oxidation-reduction potential(Eh) and p H, and microorganisms are the predominant pulling forces(active forces). The direction and kinetic energy of reactions are determined by pulling forces and then are stimulated by pushing forces. These two types of forces are analyzed and discussed separately. Based on the analysis of driving mechanisms, possible solutions to wetland N pollutions are proposed at individual, regional and global scales, respectively. Additional research needs are addressed to obtain a thorough understanding of N transport and transformations in wetlands and to reduce detrimental impacts of excessive N on such fragile ecosystems.展开更多
文摘Geopotential, dynamic, orthometric and normal height systems and the corrections related to these systems are evaluated in this paper. Along two different routes, with a length of about 5 kilometers, precise leveling and gravity measurements are done. One of the routes is in an even field while the other is in a rough field. The magnitudes of orthometric, normal and dynamic corrections are calculated for each route. Orthometric, dynamic, and normal height differences are acquired by adding the corrections to the height differences obtained from geometric leveling. The magnitudes of the corrections between the two routes are compared. In addition, by subtracting orthometric, dynamic, and normal heights from geometric leveling, deviations of these heights from geometric leveling are counted.
文摘It is a general knowledge that French as a language is widely spoken internationally whereas Urhobo is mainly spoken in the geographical location where it belongs. It is also spoken, and this, sparingly so, by Urhobo persons in the Diaspora. Presently, Urhobo has become a language of study at the Delta State University, Abraka. It has also been included in the educational curriculum for study at the lower cadre of secondary school education in the Delta State. This situation has triggered the author＇s interest in doing a contrastive phonological study. The significance of this study is that it will highlight the salient differences in some of the grammatical aspects in the languages under consideration and also identify the difficulties that learners experience as a result of these difficulties. The author will also, as much as it is possible, proffer solutions to these learning difficulties.
文摘The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new signs of vegetative and reproductive organs have been checked out and elaborated. It leads to the clarifying of new taxonomic status and geographical distribution of certain critical taxa. A set of species are threatened and need special measures which are included into the Red Data Book of Russian Federation. for their conservation. There are 13 species and one variety
基金National Basic Research Program of China(No.2010CB951704)National Natural Science Foundation of China(No.41271068)
文摘The Chinese yew（Taxus wallichiana）,which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diversity within this species at the genetic and ecological levels,its genetic patterns and range dynamics must first be identified and mapped.This knowledge can then be applied in the development of an effective conservation strategy.Based on molecular data obtained from 48 populations of T.wallichiana,we used GIS-based interpolation approach for the explicit visualization of patterns of genetic divergence and diversity,and a number of potential evolutionary hotspots have been specifically identified within the genetic landscape maps.Within the maps of genetic divergence and diversity,five areas of high inter-population genetic divergence and six areas of high intra-population genetic diversity have been highlighted in a number of separate mountain regions,and these evolutionary hotspots should have the priority to be protected.Furthermore,four geographical barriers have been identified： the eastern Himalayas,the Yunnan Plateau,the Hengduan Mountains and the Taiwan Strait.According to ecological niche modeling（ENM）,the populations of T.wallichiana within the Sino-Himalayan Forest floristic subkingdom experienced westward expansion from the periods of Last Inter-glacial to Last Glacial Maximum（LGM）.Following the LGM,the distribution range overall became reduced and fragmented.These findings challenge the classic mode of contraction-expansion in response to the last glaciation.In conclusion,our findings suggest that the changes in geographical landscapes and climate that occurred during the Quaternary resulted in current genetic landscape patterns.
文摘Contrasting multiple organisms with similar contemporary distributions, researchers can identify shared evolutionary patterns and provide historical context for community composition. We used three species complexes with overlapping distributions in Southeastern China and surrounding islands to explore the phylogeographic history of the region. Despite similar geographic distributions, genetic data revealed few congruent patterns, but all complexes displayed genetic divergence for Taiwan Residents populations. Additionally, niche modeling and divergence dating did not find support for diversification associated with the Last Glacial Maximum [Current Zoology 61 （5）： 943-950,2015].
基金the National Natural Science Foundation of China (Grant No. 41272249)Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20110072110020)
文摘As an essential component of proteins and genetic material for all organisms, nitrogen(N) is one of the major limiting factors that control the dynamics, biodiversity and functioning of lacustrine wetlands, in which intensified N biogeochemical activities take place. Reactive N loaded into wetland ecosystems has been doubled due to various human activities, including industrial, agricultural activities and urbanization. The main driving mechanisms of N transport and transformation in lacustrine wetlands are categorized to pushing forces and pulling forces in this study. Geomorphology, wetland age, N concentrations, and temperature are the main pushing forces(passive forces); whereas water table variation, oxygen concentration, other elements availability, oxidation-reduction potential(Eh) and p H, and microorganisms are the predominant pulling forces(active forces). The direction and kinetic energy of reactions are determined by pulling forces and then are stimulated by pushing forces. These two types of forces are analyzed and discussed separately. Based on the analysis of driving mechanisms, possible solutions to wetland N pollutions are proposed at individual, regional and global scales, respectively. Additional research needs are addressed to obtain a thorough understanding of N transport and transformations in wetlands and to reduce detrimental impacts of excessive N on such fragile ecosystems.
