Lignite samples collected from Vastan, Rajpardi and Tadkeshwar lignite mines of Cambay basin (Gujarat) were subjected to organic petrographic investigations and geochemical analyses and the data, thus generated, is ...Lignite samples collected from Vastan, Rajpardi and Tadkeshwar lignite mines of Cambay basin (Gujarat) were subjected to organic petrographic investigations and geochemical analyses and the data, thus generated, is used to reconstruct the paleodepositional history of these lignite sequences. The lignites of Cambay basin dominantly comprise huminite maceral group (71.6%-86.3%) followed by liptinite (10.1%-19.3%) and inertinite (3.6%-11.0%) maceral groups. The mineral matter varies from 9.0% to 20.0%. The petrography based facies model indicates that these lignites have high values of gelification index (GI) and low tissue preservation index revealing a continuous wet condition in the basin and a relatively slower rate of subsidence during the decay of organic matter. On several occasions, during the formation of seams in Tadkeshwar, Rajpardi and Vastan mines, the value of GI exceeded 10 which indicates a forest permanently flooded and the cause of pronounced degree of degradation. However, few sections in Tadkeshwar seam had relatively drier spells of environmental conditions due to fluctuation in the water table as revealed by moderately high content of inertinite macerals. This is specially indicated by the occurrence of funginite which normally thrives in the upper oxy- genated peatigenic layer and indicates prevalence of oxic conditions during plant deposition. Such conditions prevailed during a transgressive phase but there were intermittent fluvial activities also giving rise to supratidal flood plain as reflected in the form of associated carbonaceous shales in the basin.展开更多
Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the p...Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr^(-1)) were calculated on the basis of ln(^(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ^(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.展开更多
Sequencing technology has developed rapidly in recent years. Complete or nearly complete mitochondrial genomes(mitogenomes) of 155 species from 47 families in Heteroptera have been sequenced. However, the amounts of m...Sequencing technology has developed rapidly in recent years. Complete or nearly complete mitochondrial genomes(mitogenomes) of 155 species from 47 families in Heteroptera have been sequenced. However, the amounts of mitogenomes between those families are unbalanced, which makes it difficult to correctly discern the patterns of mitogenome rearrangement in Heteroptera. Among 21 species from ten families, ten variations in mitogenome rearrangement had been previously reported, among which the translocation between tRNA-Thr and tRNA-Pro was considered as a synapomorphy of Pyrrhocoroidea based on two mitogenomes. As only one mitogenome in each of Largidae and Pyrrhocoridae had been sequenced to conclude the synapomorphy, more mitogenomes of Pyrrhocoroidea need to be explored. In this study, additional two mitogenomes of Pyrrhocoroidea(Macrocheraia grandis grandis(Gray, 1832) and Myrmoplasta mira Gerst-cker, 1892) were sequenced. Both of them also possess the same translocation between tRNA-Thr and tRNA-Pro, which reaffirms that this kind of rearrangement is a molecular synapomorphy of Pyrrhocoroidea. Moreover, we discovered a more complex rearrangement in Myrmoplasta mira, in which six nearly identical duplications of tRNA-Thr were found located downstream of tRNA-Pro. Considering the high biodiversity of Heteroptera, more mitogenomic studies are needed to improve our knowledge about mitogenome rearrangements and the potential synapomorphies.展开更多
Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve ...Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve the life of the dies in cold rotary forging.The purpose of this work is to reveal the contact force responses in cold rotary forging through the modelling and simulation.For this purpose,a 3D elastic-plastic dynamic explicit FE model of cold rotary forging is developed using the FE code ABAQUS/Explicit.Through the modelling and simulation,the distribution and evolution of the contact force in cold rotary forging is investigated in detail.The experiment has been conducted and the validity of the 3D FE model of cold rotary forging has been verified.The results show that: 1) The contact force distribution is complex and exhibits an obvious non-uniform characteristic in the radial and circumferential directions; 2) The maximum contact force between the upper die and the workpiece is much larger than that between the lower die and the workpiece; 3) The contact force evolution history is periodic and every period experiences three different stages; 4) The total normal contact force is much larger than the total shear contact force at any given time.展开更多
In order to reconstruct the paleoproductivity evolution history of the West Philippine Sea during the last 700 ka, the vertical gradient of Δδ13C in dissolved inorganic carbon Δδ13C between those of foraminifera P...In order to reconstruct the paleoproductivity evolution history of the West Philippine Sea during the last 700 ka, the vertical gradient of Δδ13C in dissolved inorganic carbon Δδ13C between those of foraminifera Pulleniatina obliquiloculata and Cibicidoides wuellerstorfi) and planktonic foraminiferal assemblages were analysed in piston Core MD06-3047 retrieved from the Benham Rise (east of the Luzon Island). Paleoproductivity evolution in the West Philippine Sea during the last 700 ka is closely related to glacial-interglacial cycles and precession-controlled insolation. Controlling factors ofpaleoproductivity could have been both thermocline fluctuations related with ENSO-Iike processes and eolian input associated with East Asian winter monsoon, and the former could have been the primary factor. A higher productivity and a shallower thermocline coeval with the occurrence of low CO2 concentrations in the EPICA Dome C ice core might indicate that biological export production in the low-latitude could act as a significant sink in the global carbon cycle, and modify atmospheric CO2 concentrations. Spectral analysis further reveals that the paleoproductivity is mainly controlled by thermocline fluctuations subjected to ENSO processes responding to processional variability of insolation. High coherences in eccentricity, obliquity and precession periods fiuther revealing the close link between thermocline fluctuations, paleoproductivity and atmospheric CO2 levels.展开更多
The history of the formation and development of Chinese civilization is also a civilization history of water conservancy. Water not only gives birth to Chinese civilization but also gives birth to the unique regional ...The history of the formation and development of Chinese civilization is also a civilization history of water conservancy. Water not only gives birth to Chinese civilization but also gives birth to the unique regional culture in Lingnan. In the past thousands of year, from the ancient myths and legends of Lingnan water conservancy culture to the digging of efficacious Canal's integration of the nationalities in Lingnan, to the blending of water and culture of the Xijiang River and the North River of the Zhujiang water system and the formation of urban river culture, development of its generation, deduction and inheritance has the mutual penetration with the formation of water system and the variation of water conservancy which mutually influence the historical evolvement of Lingnan regional culture.展开更多
The content of China's economic transformation is not single, and this article argues that it includes three parts. The first is the reform of economic system, the second is the change in the pattern of economic grow...The content of China's economic transformation is not single, and this article argues that it includes three parts. The first is the reform of economic system, the second is the change in the pattern of economic growth, and the third is the adjustment of economic structure. Government is the leading force of China's economic transformation, and repeated reform of government institutions has brought about some changes to government functions. But problems are obvious that lag changes of government functions have become an obstacle in China's economic transformation. This article describes the historical evolution and the reality of China's economic transformation, and analyzes the main reasons of lag changes in government functions, and reveals that the transformation of government functions is the key for successful transformation of China's economy.展开更多
This article from the perspective of sports science and sociology to explain the origin and development ofansai waist drum, analyzes the historical evolution of ansai waist drum, analysis of ansai waist drum in proble...This article from the perspective of sports science and sociology to explain the origin and development ofansai waist drum, analyzes the historical evolution of ansai waist drum, analysis of ansai waist drum in problems existing in the process of development, and according to the analysis and the reality put forward the countermeasures of development of ansai waist drum inheritance: transmission of ansai waist drum based on school, and innovation of art form, "waist drum troupe" building, the establishment of various rules and regulations and the drummer cultivation mechanism and strengthening network, books, magazines and other publicity and performances.展开更多
There are over 100 historically black colleges and universities (HBCUs) in the United States. The majority of these HBCUs are located in the southeast section of the United States. HBCUs are a major supplier of cert...There are over 100 historically black colleges and universities (HBCUs) in the United States. The majority of these HBCUs are located in the southeast section of the United States. HBCUs are a major supplier of certified public accountants (CPAs) to the profession. Therefore, the performance of candidates from HBCUs should be of interest to various constituents including educators, employers, parents, students, and other stakeholders. The purpose of this paper is to provide statistical performance on the 2011 CPA examination for large, middle, and small HBCUs based upon the number of testing events taken. Taking a testing event is not the same as passing a testing event. This was the dichotomy between quantity and quality of HBCUs' performances. For large HBCUs, Morehouse University, North Carolina Agricultural and Technical State University (NC A&T), and Tennessee State University (TSU) were cited. For middle HBCUs, Albany State University, Norfolk State University (NSU), and North Carolina Central University (NCCU) were cited. For small HBCUs, Alcorn State University, Fisk University, and University of Maryland Eastern Shore (UMES) were cited. The dichotomy between quantity and quality is real.展开更多
This paper aims to compare and contrast two site-specific performance productions, both designed to grapple with processes of cultural remembrance, whilst also operating as successful tourist attractions. The narrativ...This paper aims to compare and contrast two site-specific performance productions, both designed to grapple with processes of cultural remembrance, whilst also operating as successful tourist attractions. The narratives encompassed by both productions revolve around shared Australian histories, for audiences attracted by place and what it is able to represent. Re-enactments of past events call into the present a consideration of what still remains, with both shows enabling new subjective interpretations of earlier times. The defining difference between the two, however, rests in the context of each performance, in the one case as a commodification of heritage and in the other case as the desire to produce an artistic yet popular theatrical product. Ballarat's, Sovereign Hill's light and sound show, Blood on the Southern Cross celebrates and commemorates, in mega-spectacle style, the Eureka Stockade, one of Australia's key historical events. Using a mechanised display of the original goldmining site of the Eureka rebellion, the performance is operated by computers with video-projection, multi-phonic sound, and moving model forms, with audiences moved around the massive site on transporters. The Piccolo Tales, a contrasting performance most notably in terms of size, unfolds the history of Kings Cross, through its setting in the miniscule iconic Piccolo Bar, in one of the tiny side streets of Sydney's bustling and densest suburb. This paper encompasses an investigation of how the cultural inscriptions of the two specific sites interweave with the performance styles, materials, political and social positioning of the works. Previous performance studies examining site-specificity are utilised, including the author's analysis of particular festival performances as "place-making" (Hayes, 2012, 2013). Smith's (2009) model of "signposts" is used to consider acting within site-specific productions in a new light, whilst both performances are more completely analysed through Schneider's (2011) concept of incomplete pasts forming "cycles of memory".展开更多
Mortars are among the first building materials used in constructions, even from prehistoric times (8th millennium BC). Their study reveals a great source of information regarding the evolution of their technological...Mortars are among the first building materials used in constructions, even from prehistoric times (8th millennium BC). Their study reveals a great source of information regarding the evolution of their technological characteristics and application techniques, the availability and exploitation of raw materials, as well the wider socio-economic aspects of each era. The aim of this paper is to comparatively evaluate the analysis results from approximately 1,000 structural mortar samples taken from various monuments and historic buildings of Greece, dated from the Hellenistic period, until the beginning of the 20th century. The analysis focused in the determination of their physico-mechanical and chemical properties, such as porosity, apparent specific gravity, mechanical strength, aggregates type and granulometry and chemical composition. Through the results' evaluation, significant remarks can be made upon the evolution of the raw materials used (binding system, aggregates, additives), as well as regarding the final properties of historic structural mortars. It is concluded that hydrated lime was the main binding agent used for a long-lasting period of 2.5 millenniums, while mixed type binding systems based on lime and natural pozzolan were systematically used for producing durable mortars, resistant to humidity. In any case, it seems that ancient masons were fully aware of the significant role of mortars in constructions and were capable of exploiting the available raw materials and application techniques to the maximum.展开更多
The feasibility analysis of projects for the preservation of the historical heritage buildings is an important problem concerning the evaluation of "the total cost of intervention", which includes all the future dam...The feasibility analysis of projects for the preservation of the historical heritage buildings is an important problem concerning the evaluation of "the total cost of intervention", which includes all the future damage costs. The total cost of intervention represents a suitable measure of the expected deterioration risk and its evolution obviously depends on the damage process which buildings are subjected to. That damage phenomena affecting masonry buildings pleased into an aggressive environment are suitably modelled by renewal processes: this happens both in the case of catastrophic events, or in the case of the so-called "natural aging", in which damage comes off gradually in time. In the hypothesis ofa Markovian renewal process (Mrp) describing the damage process, the total cost of all the future damage is evaluated taking into account both the damage aspects: damages due to catastrophic aspects and damages due to aggressive environment, supposing different maintenance and/or rehabilitation scenarios. A semi-Markov process (s-Mp) is defined to model the damage rehabilitation history of buildings in presence of seismic events, natural ageing and rehabilitation strategies. The expected rewards connected to the process are defined; they represent a significant measure of the risk.展开更多
As an ecosystem in geological history, palaeocommunity has the essence of thermodynamics. This paper introduces the concept of entropy into the study of the evolution of palaeo-community, and proposes four parameters ...As an ecosystem in geological history, palaeocommunity has the essence of thermodynamics. This paper introduces the concept of entropy into the study of the evolution of palaeo-community, and proposes four parameters to represent the structure feature of palaeo-community. This theory is used to calculate the evolution mode of branchipod community of Maokou formation in Liziya area, Huaying Moumtain, Sichuan.展开更多
Dongting Lake is the largest lake in the middle reaches of the Yangtze River in China. For centuries, people inhabiting the Dongting Lake area have been reclaiming land and constructing dams for flood resistance, agri...Dongting Lake is the largest lake in the middle reaches of the Yangtze River in China. For centuries, people inhabiting the Dongting Lake area have been reclaiming land and constructing dams for flood resistance, agricultural production, and rural settlement, forming geographical entities known as polders. In this study, the regional spatial distributions of polders in the Dongting Lake area in 1949, 1998, and 2013 were obtained using historical maps and modern remotely sensed data, revealing changes since the establishment of the People's Republic of China. Nanxian County was then selected to demonstrate polder changes at the county level, because it has undergone the most dramatic changes in the area. Different polder change models for the Datonghu, Yule, and Renhe polders were analyzed for eight periods: 1644(the early Qing Dynasty), 1911(the late Qing Dynasty), 1930(the Republic of China), 1949(the People's Republic of China), 1963, 1970, 1998, and 2013. Three resulting polder evolution models are: 1) reclaiming polders from lakes, 2) integrating polders by stream merging, and 3) abandoning polders for flood release. The polder evolution models demonstrate the wisdom of local people in using land resources according to the specific regional conditions. Throughout their long-term historical evolution, the spatial distribution of polders in the Dongting Lake area tended to be homogeneous, and the degree of human disturbance tended to be stable. However, a shift occurred, from pure polder area growth or removal to more comprehensive management and protection of the regional environment.展开更多
The 2015/16 El Nio developed from weak warm conditions in late 2014 and NINO3.4 reached 3℃ in November 2015. We describe the characteristics of the evolution of the 2015/16 El Nio using various data sets including ...The 2015/16 El Nio developed from weak warm conditions in late 2014 and NINO3.4 reached 3℃ in November 2015. We describe the characteristics of the evolution of the 2015/16 El Nio using various data sets including SST, surface winds,outgoing longwave radiation and subsurface temperature from an ensemble operational ocean reanalyses, and place this event in the context of historical ENSO events since 1979. One salient feature about the 2015/16 El Nio was a large number of westerly wind bursts and downwelling oceanic Kelvin waves(DWKVs). Four DWKVs were observed in April-November 2015 that initiated and enhanced the eastern-central Pacific warming. Eastward zonal current anomalies associated with DWKVs advected the warm pool water eastward in spring/summer. An upwelling Kelvin wave(UWKV) emerged in early November 2015 leading to a rapid decline of the event. Another outstanding feature was that NINO4 reached a historical high(1.7℃), which was 1℃(0.8℃) higher than that of the 1982/83(1997/98) El Nio . Although NINO3 was comparable to that of the 1982/83 and 1997/98 El Nio , NINO1+2 was much weaker. Consistently, enhanced convection was displaced 20 degree westward, and the maximum D20 anomaly was about 1/3.1/2 of that in 1997 and 1982 near the west coast of South America.展开更多
Clay mineral assemblages and crystallinities in sediments from IODP Site 1340 in the Bering Sea were analyzed in order to trace sediment sources and reconstruct the paleoclimatic history of the Bering Sea since Plioce...Clay mineral assemblages and crystallinities in sediments from IODP Site 1340 in the Bering Sea were analyzed in order to trace sediment sources and reconstruct the paleoclimatic history of the Bering Sea since Pliocene (the last -4.3 Ma). The re- sults show that clay minerals at Site U1340 are dominated by illite, with a moderate amount of smectite and chlorite, and minor kaolinite. Sediment source studies suggest that the clay mineral assemblages and their sources in the studied core are controlled primarily by the climate conditions. During the warm periods, clay minerals originated mainly from the adjacent Aleutian Is- lands, and smectite/(illite+chlorite) ratios increased. During the cold periods, clay minerals from the Alaskan region distinctly increased, and smectite/(illite+chlorite) ratios declined. Based on smectite/(illite+chlorite) ratios and clay mineral crystallinities the evolutionary history of the paleoclimate was revealed in the Bering Sea. In general, the Bering Sea was characterized by warm and wet climate condition from 4.3 to 3.94 Ma, and then cold and dry condition associated with the enhanced volcanism from 3.94 to 3.6 Ma. Thereafter, the climate gradually became cold and wet, and then was dominated by a cold and dry condi- tion since 2.74 Ma, probably induced by the intensification of the Northern Hemisphere Glaciation. The interval from 1.95 to 1.07 Ma was a transitional period of the climate gradually becoming cold and wet. After the middle Pleistocene transition (1.07 to 0.8 Ma), the Bering Sea was governed mainly by cold and wet climate with several intervals of warm climate at -0.42 Ma (MIS 11), -0.33 Ma (MIS 9) and ~0.12 Ma (MIS 5), respectively. During the last 9.21 ka (the Holocene), the Bering Sea was characterized primarily by relatively warm and wet climatic conditions.展开更多
文摘Lignite samples collected from Vastan, Rajpardi and Tadkeshwar lignite mines of Cambay basin (Gujarat) were subjected to organic petrographic investigations and geochemical analyses and the data, thus generated, is used to reconstruct the paleodepositional history of these lignite sequences. The lignites of Cambay basin dominantly comprise huminite maceral group (71.6%-86.3%) followed by liptinite (10.1%-19.3%) and inertinite (3.6%-11.0%) maceral groups. The mineral matter varies from 9.0% to 20.0%. The petrography based facies model indicates that these lignites have high values of gelification index (GI) and low tissue preservation index revealing a continuous wet condition in the basin and a relatively slower rate of subsidence during the decay of organic matter. On several occasions, during the formation of seams in Tadkeshwar, Rajpardi and Vastan mines, the value of GI exceeded 10 which indicates a forest permanently flooded and the cause of pronounced degree of degradation. However, few sections in Tadkeshwar seam had relatively drier spells of environmental conditions due to fluctuation in the water table as revealed by moderately high content of inertinite macerals. This is specially indicated by the occurrence of funginite which normally thrives in the upper oxy- genated peatigenic layer and indicates prevalence of oxic conditions during plant deposition. Such conditions prevailed during a transgressive phase but there were intermittent fluvial activities also giving rise to supratidal flood plain as reflected in the form of associated carbonaceous shales in the basin.
基金supported by the National Key Scientific Research Project on Global Climate Change (Grant No. 2010CB 951203)the National Natural Science Foundation of China (Grant Nos. 41206057, 41576067, 41376075 and 41576061)
文摘Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr^(-1)) were calculated on the basis of ln(^(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ^(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.
基金financially supported by the Ministry of Culture of the Czech Republic(DKRVO 2019/5.I.a,National Museum,00023272)
文摘Sequencing technology has developed rapidly in recent years. Complete or nearly complete mitochondrial genomes(mitogenomes) of 155 species from 47 families in Heteroptera have been sequenced. However, the amounts of mitogenomes between those families are unbalanced, which makes it difficult to correctly discern the patterns of mitogenome rearrangement in Heteroptera. Among 21 species from ten families, ten variations in mitogenome rearrangement had been previously reported, among which the translocation between tRNA-Thr and tRNA-Pro was considered as a synapomorphy of Pyrrhocoroidea based on two mitogenomes. As only one mitogenome in each of Largidae and Pyrrhocoridae had been sequenced to conclude the synapomorphy, more mitogenomes of Pyrrhocoroidea need to be explored. In this study, additional two mitogenomes of Pyrrhocoroidea(Macrocheraia grandis grandis(Gray, 1832) and Myrmoplasta mira Gerst-cker, 1892) were sequenced. Both of them also possess the same translocation between tRNA-Thr and tRNA-Pro, which reaffirms that this kind of rearrangement is a molecular synapomorphy of Pyrrhocoroidea. Moreover, we discovered a more complex rearrangement in Myrmoplasta mira, in which six nearly identical duplications of tRNA-Thr were found located downstream of tRNA-Pro. Considering the high biodiversity of Heteroptera, more mitogenomic studies are needed to improve our knowledge about mitogenome rearrangements and the potential synapomorphies.
基金Project(51105287)supported by the National Natural Science Foundation of ChinaProject(2012BAA08003)supported by the Key Research and Development Project of New Products and New Technologies of Hubei Province,ChinaProject(2013M531750)supported by China Postdoctoral Science Foundation
文摘Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve the life of the dies in cold rotary forging.The purpose of this work is to reveal the contact force responses in cold rotary forging through the modelling and simulation.For this purpose,a 3D elastic-plastic dynamic explicit FE model of cold rotary forging is developed using the FE code ABAQUS/Explicit.Through the modelling and simulation,the distribution and evolution of the contact force in cold rotary forging is investigated in detail.The experiment has been conducted and the validity of the 3D FE model of cold rotary forging has been verified.The results show that: 1) The contact force distribution is complex and exhibits an obvious non-uniform characteristic in the radial and circumferential directions; 2) The maximum contact force between the upper die and the workpiece is much larger than that between the lower die and the workpiece; 3) The contact force evolution history is periodic and every period experiences three different stages; 4) The total normal contact force is much larger than the total shear contact force at any given time.
基金Supported by the National Natural Science Foundation of China(Nos.41230959,41076030,40906038,41106042,41006032)the Pilot Project of the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-221)the Foundation of Key Laboratory of Marine Geology and Environment of Chinese Academy of Sciences(No.MGE2011KG01)
文摘In order to reconstruct the paleoproductivity evolution history of the West Philippine Sea during the last 700 ka, the vertical gradient of Δδ13C in dissolved inorganic carbon Δδ13C between those of foraminifera Pulleniatina obliquiloculata and Cibicidoides wuellerstorfi) and planktonic foraminiferal assemblages were analysed in piston Core MD06-3047 retrieved from the Benham Rise (east of the Luzon Island). Paleoproductivity evolution in the West Philippine Sea during the last 700 ka is closely related to glacial-interglacial cycles and precession-controlled insolation. Controlling factors ofpaleoproductivity could have been both thermocline fluctuations related with ENSO-Iike processes and eolian input associated with East Asian winter monsoon, and the former could have been the primary factor. A higher productivity and a shallower thermocline coeval with the occurrence of low CO2 concentrations in the EPICA Dome C ice core might indicate that biological export production in the low-latitude could act as a significant sink in the global carbon cycle, and modify atmospheric CO2 concentrations. Spectral analysis further reveals that the paleoproductivity is mainly controlled by thermocline fluctuations subjected to ENSO processes responding to processional variability of insolation. High coherences in eccentricity, obliquity and precession periods fiuther revealing the close link between thermocline fluctuations, paleoproductivity and atmospheric CO2 levels.
文摘The history of the formation and development of Chinese civilization is also a civilization history of water conservancy. Water not only gives birth to Chinese civilization but also gives birth to the unique regional culture in Lingnan. In the past thousands of year, from the ancient myths and legends of Lingnan water conservancy culture to the digging of efficacious Canal's integration of the nationalities in Lingnan, to the blending of water and culture of the Xijiang River and the North River of the Zhujiang water system and the formation of urban river culture, development of its generation, deduction and inheritance has the mutual penetration with the formation of water system and the variation of water conservancy which mutually influence the historical evolvement of Lingnan regional culture.
文摘The content of China's economic transformation is not single, and this article argues that it includes three parts. The first is the reform of economic system, the second is the change in the pattern of economic growth, and the third is the adjustment of economic structure. Government is the leading force of China's economic transformation, and repeated reform of government institutions has brought about some changes to government functions. But problems are obvious that lag changes of government functions have become an obstacle in China's economic transformation. This article describes the historical evolution and the reality of China's economic transformation, and analyzes the main reasons of lag changes in government functions, and reveals that the transformation of government functions is the key for successful transformation of China's economy.
文摘This article from the perspective of sports science and sociology to explain the origin and development ofansai waist drum, analyzes the historical evolution of ansai waist drum, analysis of ansai waist drum in problems existing in the process of development, and according to the analysis and the reality put forward the countermeasures of development of ansai waist drum inheritance: transmission of ansai waist drum based on school, and innovation of art form, "waist drum troupe" building, the establishment of various rules and regulations and the drummer cultivation mechanism and strengthening network, books, magazines and other publicity and performances.
文摘There are over 100 historically black colleges and universities (HBCUs) in the United States. The majority of these HBCUs are located in the southeast section of the United States. HBCUs are a major supplier of certified public accountants (CPAs) to the profession. Therefore, the performance of candidates from HBCUs should be of interest to various constituents including educators, employers, parents, students, and other stakeholders. The purpose of this paper is to provide statistical performance on the 2011 CPA examination for large, middle, and small HBCUs based upon the number of testing events taken. Taking a testing event is not the same as passing a testing event. This was the dichotomy between quantity and quality of HBCUs' performances. For large HBCUs, Morehouse University, North Carolina Agricultural and Technical State University (NC A&T), and Tennessee State University (TSU) were cited. For middle HBCUs, Albany State University, Norfolk State University (NSU), and North Carolina Central University (NCCU) were cited. For small HBCUs, Alcorn State University, Fisk University, and University of Maryland Eastern Shore (UMES) were cited. The dichotomy between quantity and quality is real.
文摘This paper aims to compare and contrast two site-specific performance productions, both designed to grapple with processes of cultural remembrance, whilst also operating as successful tourist attractions. The narratives encompassed by both productions revolve around shared Australian histories, for audiences attracted by place and what it is able to represent. Re-enactments of past events call into the present a consideration of what still remains, with both shows enabling new subjective interpretations of earlier times. The defining difference between the two, however, rests in the context of each performance, in the one case as a commodification of heritage and in the other case as the desire to produce an artistic yet popular theatrical product. Ballarat's, Sovereign Hill's light and sound show, Blood on the Southern Cross celebrates and commemorates, in mega-spectacle style, the Eureka Stockade, one of Australia's key historical events. Using a mechanised display of the original goldmining site of the Eureka rebellion, the performance is operated by computers with video-projection, multi-phonic sound, and moving model forms, with audiences moved around the massive site on transporters. The Piccolo Tales, a contrasting performance most notably in terms of size, unfolds the history of Kings Cross, through its setting in the miniscule iconic Piccolo Bar, in one of the tiny side streets of Sydney's bustling and densest suburb. This paper encompasses an investigation of how the cultural inscriptions of the two specific sites interweave with the performance styles, materials, political and social positioning of the works. Previous performance studies examining site-specificity are utilised, including the author's analysis of particular festival performances as "place-making" (Hayes, 2012, 2013). Smith's (2009) model of "signposts" is used to consider acting within site-specific productions in a new light, whilst both performances are more completely analysed through Schneider's (2011) concept of incomplete pasts forming "cycles of memory".
文摘Mortars are among the first building materials used in constructions, even from prehistoric times (8th millennium BC). Their study reveals a great source of information regarding the evolution of their technological characteristics and application techniques, the availability and exploitation of raw materials, as well the wider socio-economic aspects of each era. The aim of this paper is to comparatively evaluate the analysis results from approximately 1,000 structural mortar samples taken from various monuments and historic buildings of Greece, dated from the Hellenistic period, until the beginning of the 20th century. The analysis focused in the determination of their physico-mechanical and chemical properties, such as porosity, apparent specific gravity, mechanical strength, aggregates type and granulometry and chemical composition. Through the results' evaluation, significant remarks can be made upon the evolution of the raw materials used (binding system, aggregates, additives), as well as regarding the final properties of historic structural mortars. It is concluded that hydrated lime was the main binding agent used for a long-lasting period of 2.5 millenniums, while mixed type binding systems based on lime and natural pozzolan were systematically used for producing durable mortars, resistant to humidity. In any case, it seems that ancient masons were fully aware of the significant role of mortars in constructions and were capable of exploiting the available raw materials and application techniques to the maximum.
文摘The feasibility analysis of projects for the preservation of the historical heritage buildings is an important problem concerning the evaluation of "the total cost of intervention", which includes all the future damage costs. The total cost of intervention represents a suitable measure of the expected deterioration risk and its evolution obviously depends on the damage process which buildings are subjected to. That damage phenomena affecting masonry buildings pleased into an aggressive environment are suitably modelled by renewal processes: this happens both in the case of catastrophic events, or in the case of the so-called "natural aging", in which damage comes off gradually in time. In the hypothesis ofa Markovian renewal process (Mrp) describing the damage process, the total cost of all the future damage is evaluated taking into account both the damage aspects: damages due to catastrophic aspects and damages due to aggressive environment, supposing different maintenance and/or rehabilitation scenarios. A semi-Markov process (s-Mp) is defined to model the damage rehabilitation history of buildings in presence of seismic events, natural ageing and rehabilitation strategies. The expected rewards connected to the process are defined; they represent a significant measure of the risk.
基金National Natural Science Foundation of China(40242012,50134040)
文摘As an ecosystem in geological history, palaeocommunity has the essence of thermodynamics. This paper introduces the concept of entropy into the study of the evolution of palaeo-community, and proposes four parameters to represent the structure feature of palaeo-community. This theory is used to calculate the evolution mode of branchipod community of Maokou formation in Liziya area, Huaying Moumtain, Sichuan.
基金Science & Technology Basic Research Program of China,No.2011FY110400,No.2013FY114600National Natural Science Foundation of China,No.41301474+1 种基金China Postdoctoral Science Foundation,No.2014T70114Disaster Risk Reduction Knowledge Service of IKCEST,CKCEST-2016-3-7
文摘Dongting Lake is the largest lake in the middle reaches of the Yangtze River in China. For centuries, people inhabiting the Dongting Lake area have been reclaiming land and constructing dams for flood resistance, agricultural production, and rural settlement, forming geographical entities known as polders. In this study, the regional spatial distributions of polders in the Dongting Lake area in 1949, 1998, and 2013 were obtained using historical maps and modern remotely sensed data, revealing changes since the establishment of the People's Republic of China. Nanxian County was then selected to demonstrate polder changes at the county level, because it has undergone the most dramatic changes in the area. Different polder change models for the Datonghu, Yule, and Renhe polders were analyzed for eight periods: 1644(the early Qing Dynasty), 1911(the late Qing Dynasty), 1930(the Republic of China), 1949(the People's Republic of China), 1963, 1970, 1998, and 2013. Three resulting polder evolution models are: 1) reclaiming polders from lakes, 2) integrating polders by stream merging, and 3) abandoning polders for flood release. The polder evolution models demonstrate the wisdom of local people in using land resources according to the specific regional conditions. Throughout their long-term historical evolution, the spatial distribution of polders in the Dongting Lake area tended to be homogeneous, and the degree of human disturbance tended to be stable. However, a shift occurred, from pure polder area growth or removal to more comprehensive management and protection of the regional environment.
文摘The 2015/16 El Nio developed from weak warm conditions in late 2014 and NINO3.4 reached 3℃ in November 2015. We describe the characteristics of the evolution of the 2015/16 El Nio using various data sets including SST, surface winds,outgoing longwave radiation and subsurface temperature from an ensemble operational ocean reanalyses, and place this event in the context of historical ENSO events since 1979. One salient feature about the 2015/16 El Nio was a large number of westerly wind bursts and downwelling oceanic Kelvin waves(DWKVs). Four DWKVs were observed in April-November 2015 that initiated and enhanced the eastern-central Pacific warming. Eastward zonal current anomalies associated with DWKVs advected the warm pool water eastward in spring/summer. An upwelling Kelvin wave(UWKV) emerged in early November 2015 leading to a rapid decline of the event. Another outstanding feature was that NINO4 reached a historical high(1.7℃), which was 1℃(0.8℃) higher than that of the 1982/83(1997/98) El Nio . Although NINO3 was comparable to that of the 1982/83 and 1997/98 El Nio , NINO1+2 was much weaker. Consistently, enhanced convection was displaced 20 degree westward, and the maximum D20 anomaly was about 1/3.1/2 of that in 1997 and 1982 near the west coast of South America.
基金supported by National Natural Science Foundation of China(Grant Nos.41476037,41076026,41276051 and 91228207)the National Key Basic Research Program of China(Grant No.2013CB956102)IODP-China
文摘Clay mineral assemblages and crystallinities in sediments from IODP Site 1340 in the Bering Sea were analyzed in order to trace sediment sources and reconstruct the paleoclimatic history of the Bering Sea since Pliocene (the last -4.3 Ma). The re- sults show that clay minerals at Site U1340 are dominated by illite, with a moderate amount of smectite and chlorite, and minor kaolinite. Sediment source studies suggest that the clay mineral assemblages and their sources in the studied core are controlled primarily by the climate conditions. During the warm periods, clay minerals originated mainly from the adjacent Aleutian Is- lands, and smectite/(illite+chlorite) ratios increased. During the cold periods, clay minerals from the Alaskan region distinctly increased, and smectite/(illite+chlorite) ratios declined. Based on smectite/(illite+chlorite) ratios and clay mineral crystallinities the evolutionary history of the paleoclimate was revealed in the Bering Sea. In general, the Bering Sea was characterized by warm and wet climate condition from 4.3 to 3.94 Ma, and then cold and dry condition associated with the enhanced volcanism from 3.94 to 3.6 Ma. Thereafter, the climate gradually became cold and wet, and then was dominated by a cold and dry condi- tion since 2.74 Ma, probably induced by the intensification of the Northern Hemisphere Glaciation. The interval from 1.95 to 1.07 Ma was a transitional period of the climate gradually becoming cold and wet. After the middle Pleistocene transition (1.07 to 0.8 Ma), the Bering Sea was governed mainly by cold and wet climate with several intervals of warm climate at -0.42 Ma (MIS 11), -0.33 Ma (MIS 9) and ~0.12 Ma (MIS 5), respectively. During the last 9.21 ka (the Holocene), the Bering Sea was characterized primarily by relatively warm and wet climatic conditions.