Geotechnical and geochemical assessment of natural sands being used as fine aggregates for construction purposes in Ahanta West and its Environs was carried out, as well as addressing the environmental problems associ...Geotechnical and geochemical assessment of natural sands being used as fine aggregates for construction purposes in Ahanta West and its Environs was carried out, as well as addressing the environmental problems associated with the exploitation of these sand through the sand winning activities. The results from geotechnical and geochemical tests were bench marked with British, American and Ottawa Standards for testing materials. Representative samples were taken from five different sand winning sites namely, Pompuni, Agona Banso, Fretsi, Tumentu stream and Fretsi river. The geotechnical tests carried out were specific gravity, grain size analysis, moisture content, silt content, permeability test using the constant head permeameter method. The photometer (Hydro Test HT 1000) was used to determine silica, sulphate and chloride concentrations in the sand samples. The oxides for the geochemical analysis w</span><span style="font-family:"">ere</span><span style="font-family:""> determined using the X-ray fluorescence (XRF) method. The results from the study areas showed that except for Fretsi, the specific gravity, grain size analysis, moisture content, silt content and permeability tests were within the acceptable range for natural sands. Sand samples from Pumponi and Agona Banso had the required Cu and Cc values of being well graded. Sulphate and chloride concentrations were within standards for all the samples;however, silica was low for all the samples. Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub>, MnO and Na<sub>2</sub>O did not meet the Ottawa sand standard. Natural sand is not recommended to be used for construction purpose</span><span style="font-family:"">s</span><span style="font-family:""> however, these sands may be treated or blended if it is to be used for construction purposes. There are serious environmental implications for the sand</span><span style="font-family:"">-</span><span style="font-family:"">winning activities in the study areas such as stripped overburden, creation of pits and ponds, increased total suspended solids in surface waters, and destruction of aquatic habitats which needs to be addressed.展开更多
The purpose of this research is to identify the historical status of Song Dynasty of China.The historical status of Song Dynasty has been a controversial topic for a long time.Song Dynasty has been remembered in diffe...The purpose of this research is to identify the historical status of Song Dynasty of China.The historical status of Song Dynasty has been a controversial topic for a long time.Song Dynasty has been remembered in different ways in China and in the West at different times.This study will discuss the advantages and disadvantages of Song Dynasty and evaluate Song Dynasty real istically and fairly.展开更多
Background: According to current taxonomy only three out of 27 Sinohimalayan leaf warbler species(Phylloscopidae) are considered genetically uniform across their entire breeding range along the Southeastern margin of ...Background: According to current taxonomy only three out of 27 Sinohimalayan leaf warbler species(Phylloscopidae) are considered genetically uniform across their entire breeding range along the Southeastern margin of the Qinghai-Tibetan Plateau, the Buff-barred Warbler(Phylloscopus pulcher) being one of them. Because marked differentiation among Himalayan and Chinese populations has been recently demonstrated for a number of Phylloscopus species(or sister species) we investigated the intraspecific variation of a mitochondrial gene, songs and morphology of P. pulcher in a phylogeographic approach.Methods: We sequenced a fragment of the mitochondrial cytochrome b, reconstructed haplotype networks and analyzed DNA polymorphism among Himalayan and Chinese populations. We measured time and frequency parameters of two distinct song types and analyzed among population-differentiation in a principal component analysis and a discriminant analysis. We also compared measurements of body size dimensions taken from museum specimens.Results: The mitochondrial haplotype network(cytb) was divided into two distinct clusters corresponding to geographic origin of samples. Pairwise genetic distances among Himalayan and Chinese mt DNA lineages account for 1.3% which coincides with Pleistocene lineage separation at roughly 650,000 years ago. Genetic diversity is slightly higher in the Chinese part of the species' range with respect to haplotype and nucleotide diversity while the less diversified Himalayan population lineage shows signs of recent range expansion. The vocal repertoire of P. pulcher comprises two distinct verse types that are combined with short interspersed click notes to long continuous song displays. Trill verse types showed significant differences among regions in almost all measured frequency and time parameters: Chinese males displayed more rapid and more broad-banded trills at a lower pitch. In contrast,warbling verse types showed a distinctively different structure among regions: Himalayan songs consisted of repeated syllables while Chinese songs comprised repetitions of single, long and strongly modulated elements.Subtle morphological differences among specimens from the two study regions could only be confirmed for plumage coloration but not for metric characters.Conclusions: Based on the genetic and bioacoustic distinctiveness of Chinese Buff-barred Warbler populations,we recommend that the name Phylloscopus pulcher vegetus Bangs, 1913 should be re-validated for this taxon.展开更多
The sedimentary strata and deposition ages of the 'old red sand' distributed along the coasts of south Fujian and west Guangdong are determined by lithostratigraphy, magnetic stratigraphy and earth chemistry c...The sedimentary strata and deposition ages of the 'old red sand' distributed along the coasts of south Fujian and west Guangdong are determined by lithostratigraphy, magnetic stratigraphy and earth chemistry combined with TL, ESR and 14C-dating techniques. The research shows that the 'old red sand' was aeolian sediments deposited from 55 400 to 9 000 aBP, the last glacial period in the middle and later age of Late Pleistocene. Most of them deposited in two periods of 56-42 ka and 30-10 ka. The 'old red sand' deposited in the period of 30-10 ka, the later Wurm glacier substage (Q33), developed on the largest scale with the widest distribution.展开更多
文摘Geotechnical and geochemical assessment of natural sands being used as fine aggregates for construction purposes in Ahanta West and its Environs was carried out, as well as addressing the environmental problems associated with the exploitation of these sand through the sand winning activities. The results from geotechnical and geochemical tests were bench marked with British, American and Ottawa Standards for testing materials. Representative samples were taken from five different sand winning sites namely, Pompuni, Agona Banso, Fretsi, Tumentu stream and Fretsi river. The geotechnical tests carried out were specific gravity, grain size analysis, moisture content, silt content, permeability test using the constant head permeameter method. The photometer (Hydro Test HT 1000) was used to determine silica, sulphate and chloride concentrations in the sand samples. The oxides for the geochemical analysis w</span><span style="font-family:"">ere</span><span style="font-family:""> determined using the X-ray fluorescence (XRF) method. The results from the study areas showed that except for Fretsi, the specific gravity, grain size analysis, moisture content, silt content and permeability tests were within the acceptable range for natural sands. Sand samples from Pumponi and Agona Banso had the required Cu and Cc values of being well graded. Sulphate and chloride concentrations were within standards for all the samples;however, silica was low for all the samples. Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub>, MnO and Na<sub>2</sub>O did not meet the Ottawa sand standard. Natural sand is not recommended to be used for construction purpose</span><span style="font-family:"">s</span><span style="font-family:""> however, these sands may be treated or blended if it is to be used for construction purposes. There are serious environmental implications for the sand</span><span style="font-family:"">-</span><span style="font-family:"">winning activities in the study areas such as stripped overburden, creation of pits and ponds, increased total suspended solids in surface waters, and destruction of aquatic habitats which needs to be addressed.
文摘The purpose of this research is to identify the historical status of Song Dynasty of China.The historical status of Song Dynasty has been a controversial topic for a long time.Song Dynasty has been remembered in different ways in China and in the West at different times.This study will discuss the advantages and disadvantages of Song Dynasty and evaluate Song Dynasty real istically and fairly.
基金performed within the scope of the Deutsche Forschungsgemeinschaft project funding for PA 1818/3-1(M.P.)supported by further grants to Y.-H.Sun from the National Natural Science Foundation of China,project No.31272286
文摘Background: According to current taxonomy only three out of 27 Sinohimalayan leaf warbler species(Phylloscopidae) are considered genetically uniform across their entire breeding range along the Southeastern margin of the Qinghai-Tibetan Plateau, the Buff-barred Warbler(Phylloscopus pulcher) being one of them. Because marked differentiation among Himalayan and Chinese populations has been recently demonstrated for a number of Phylloscopus species(or sister species) we investigated the intraspecific variation of a mitochondrial gene, songs and morphology of P. pulcher in a phylogeographic approach.Methods: We sequenced a fragment of the mitochondrial cytochrome b, reconstructed haplotype networks and analyzed DNA polymorphism among Himalayan and Chinese populations. We measured time and frequency parameters of two distinct song types and analyzed among population-differentiation in a principal component analysis and a discriminant analysis. We also compared measurements of body size dimensions taken from museum specimens.Results: The mitochondrial haplotype network(cytb) was divided into two distinct clusters corresponding to geographic origin of samples. Pairwise genetic distances among Himalayan and Chinese mt DNA lineages account for 1.3% which coincides with Pleistocene lineage separation at roughly 650,000 years ago. Genetic diversity is slightly higher in the Chinese part of the species' range with respect to haplotype and nucleotide diversity while the less diversified Himalayan population lineage shows signs of recent range expansion. The vocal repertoire of P. pulcher comprises two distinct verse types that are combined with short interspersed click notes to long continuous song displays. Trill verse types showed significant differences among regions in almost all measured frequency and time parameters: Chinese males displayed more rapid and more broad-banded trills at a lower pitch. In contrast,warbling verse types showed a distinctively different structure among regions: Himalayan songs consisted of repeated syllables while Chinese songs comprised repetitions of single, long and strongly modulated elements.Subtle morphological differences among specimens from the two study regions could only be confirmed for plumage coloration but not for metric characters.Conclusions: Based on the genetic and bioacoustic distinctiveness of Chinese Buff-barred Warbler populations,we recommend that the name Phylloscopus pulcher vegetus Bangs, 1913 should be re-validated for this taxon.
文摘The sedimentary strata and deposition ages of the 'old red sand' distributed along the coasts of south Fujian and west Guangdong are determined by lithostratigraphy, magnetic stratigraphy and earth chemistry combined with TL, ESR and 14C-dating techniques. The research shows that the 'old red sand' was aeolian sediments deposited from 55 400 to 9 000 aBP, the last glacial period in the middle and later age of Late Pleistocene. Most of them deposited in two periods of 56-42 ka and 30-10 ka. The 'old red sand' deposited in the period of 30-10 ka, the later Wurm glacier substage (Q33), developed on the largest scale with the widest distribution.
