The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of ...The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].展开更多
The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negati...The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data(as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979(116.47 × 10~3 ha) to 2012(2205.65 × 10~3 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13 th Five-Year Fisheries Planning' is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.展开更多
Historically Turks had always relied on military power. The culture is rich with martial values to this day. Even each civilian is somewhat soldierly in a sense, in general. Nevertheless, in a more detailed analysis, ...Historically Turks had always relied on military power. The culture is rich with martial values to this day. Even each civilian is somewhat soldierly in a sense, in general. Nevertheless, in a more detailed analysis, in some territories of the country, the prestige enjoyed by the military is more intensive than the average, while in some other territories, respect for military people is much below the average tendency. One might infer that in the former category, it is a question of the regions where the inhabitants are mild, soft-spoken, and compatible. They accordingly admire discipline and display obedient attitudes vis-a-vis governmental authority ever since the Ottoman times, merely as a cultural and traditional trait. Those regions are certainly places where military people today are held in high esteem. In such locations, even the ideal profession for a little boy is indoctrinated as a military career, by the whole family or the surrounding social environment. It should be mentioned that in certain cities and towns, a substantial percentage of the population are represented by immigrants, who got re-patriated along the course of the near history, as the former Ottoman Empire began shrinking in territory due to loss of land, during successive wars. The crushing majority of the Muslim Ottoman subjects in those lost territories preferred leaving their property and escaping into the Anatolian mainland, rather than renouncing their belief and assimilating to the new political regime. Having suffered at the hands of foreign powers, those people have also been especially appreciative of the value of their own soldiers. As for the latter category, dislike of discipline and authority can be mainly attributed to the special social structure and historical circumstances.展开更多
Since China's reform and accession to the world trade organization (WTO), the international labor division, cooperation, and communication of production have been a direction of the global productivity development....Since China's reform and accession to the world trade organization (WTO), the international labor division, cooperation, and communication of production have been a direction of the global productivity development. The expansion of the world trade organization and the growth of multinational corporations have promoted China's market economy to head for internationalization; the exchanges of all countries' science and technology, culture, and education have become increasingly frequent and beyond the borders very early, so opening-up has become a world trend. China is playing an important role in this historical process. In this situation, the importance of language translation is increasing day by day, and an unprecedented prosperous situation has especially appeared to the interpretation. In order to accord with this new historical situation, many colleges and universities have set up language translation program and have offered interpretation course. To promote the economic development of China and train more senior interpreters, the studies of interpretation teaching and the improvement of interpretation teaching quality have been particularly important. In this paper, the relationship among memory, note-taking, and psychological factors are analyzed.展开更多
Through synthetic researches of multi-index geological records of Niya section, which are of high resolution in southern margin of Tarim Basin, this paper has reconstructed the sequences of paleoclimate in this region...Through synthetic researches of multi-index geological records of Niya section, which are of high resolution in southern margin of Tarim Basin, this paper has reconstructed the sequences of paleoclimate in this region during historical times (since about 4000a B.P.). During the last 4000 years, the area has experienced alternations of relative cold-moisture and relative warm-dry periods. Three evident cold-moisture periods and three warm-dry periods are identifing. The study shows that the human activities have an intimate relation with the evolution of paleoclimate in the southern Xinjiang. Paleoclimate has played very important role in influencing human being′s agricultural activities.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
In this article the crucial role of the Lutheran Church in Sweden in neighboring Lutheran Danish enemies in the province of Scania into the pseudo-indigenization process of making loyal Swedish citizen after the peace...In this article the crucial role of the Lutheran Church in Sweden in neighboring Lutheran Danish enemies in the province of Scania into the pseudo-indigenization process of making loyal Swedish citizen after the peace treaty of Roskilde 1658, and more pronounced after 1678, is described and discussed. The process included educational, pedagogical, judicial, liturgical and theological-rhetorical means and had significant, invaluable, and long lasting consequences. The province remains as a part of the Kingdom of Sweden. From a historical perspective, the process was fast and successful, even though some modem historians question the speediness of the process and thereby want to modify the picture of a fast and non-problematic Swedification or pseudo-indigenization process.展开更多
A central tenet of coevolutionary theory,including theory of the coevolutionary relationship between brood parasites and their hosts,is that temporal and spatial patterns may reveal important information about ecologi...A central tenet of coevolutionary theory,including theory of the coevolutionary relationship between brood parasites and their hosts,is that temporal and spatial patterns may reveal important information about ecological and evolutionary dynamics.For instance,level of genetic structure of populations provides important information about the role of genetics and gene ow in determining local patterns of selection on hosts due to parasitism(i.e.,egg rejection) and on parasites due to selection by hosts(i.e.,egg mimicry).Furthermore,abiotic(i.e.,climatic conditions) and biotic(phenotypic characteristics of animals) factors that also vary spatially may directly or indirectly a ect populations of hosts and brood parasites and,therefore,their interaction.By reviewing the literature,we found considerable evidence for an e ect of the spatially and temporally structured abiotic environment on the phenotype of both parasite and host eggs and the degree of mimicry.Moreover,we found examples suggesting that speci c life history characteristics of hosts that vary geographically and/or temporally may a ect the probability of initial colonization of a new host species and the direction and the speed of coevolution.We provide an exhaustive review of studies investigating temporal and spatial patterns of the interaction between brood parasites and their hosts.Such temporal and spatial trends in parasite and host traits are,together with genetic information on rejection and signi cant e ects of gene ow,consistent with coevolutionary dynamics.However,gene ow and changes in the temporal and spatial patterns of abundance of both parasites and hosts may result in frequent cases of counter-intuitive relationships between the phenotype of the parasite and that of the host(i.e.,poor or no mimicry),which may suggest limits to the degree of adaptation.We provide a list of scienti c questions in need of further investigation,concluding that studies of brood parasites and their hosts may play a central role in testing the geographic theory of coevolution and several alternative hypotheses.展开更多
CCPIT is a professional promo- tion in international business exchange.We draw this con- clusion not only because of its vast geography coverage by 16 overseas representative offices,50
The silkworm,Bombyx mori,played an important role in the old Silk Road that connected ancient Asia and Europe.However,to date,there have been few studies of the origins and domestication of this species using molecula...The silkworm,Bombyx mori,played an important role in the old Silk Road that connected ancient Asia and Europe.However,to date,there have been few studies of the origins and domestication of this species using molecular methods.In this study,DNA sequences of mitochondrial and nuclear loci were used to infer the phylogeny and evolutionary history of the domesticated silkworm and its relatives.All of the phylogenetic analyses indicated a close relationship between the domesticated silkworm and the Chinese wild silkworm.Domestication was estimated to have occurred about 4100 years ago(ya),and the radiation of the different geographic strains of B.mori about 2000 ya.The Chinese wild silkworm and the Japanese wild silkworm split about 23600 ya.These estimates are in good agreement with the fossil evidence and historical records.In addition,we show that the domesticated silkworm experienced a population expansion around 1000 ya.The divergence times and the population dynamics of silkworms presented in this study will be useful for studies of lepidopteran phylogenetics,in the genetic analysis of domestic animals,and for understanding the spread of human civilizations.展开更多
The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major adva...The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major advances in the last few decades,the evolutionary history and possible mechanisms of Eocene climate change in the northeastern Tibetan Plateau remain unclear.The Xining Basin in the northeastern Tibetan Plateau contains a continuous sequence of Early to Late Eocene non-marine sediments which provides the opportunity to resolve long-term climate changes during this period. In this study, we report the results of analyses of lithofacies, sediment color and geochemistry of bulk samples collected from the Xijigou section of the Xining Basin. An abrupt lithofacies change between the Early(~52–40 Ma) and Late Eocene(~40–34 Ma) indicates a change in the depositional environment from a shallow lake to a playa lake in response to a significant climatic shift. During ~52–40 Ma,higher values of sediment redness(a*), redness/lightness(a*/L*) and higher modified Chemical Index of Weathering(CIW′)indicate a relatively warm and humid climate, while from ~40–34 Ma the lower values of a*, a*/L*and lower CIW′ imply subhumid to semi-arid climatic conditions. The paleoclimatic records indicate a long-term(~52–34 Ma) trend of decreasing chemical weathering, consistent with global climate change. An abrupt sharp excursion of the proxy records during ~42–40 Ma suggests a relatively brief warm interval, corresponding to the Middle Eocene Climatic Optimum(MECO). We suggest that global cooling substantially reduced humidity in inner Asia, resulting in sub-humid to semi-arid climatic conditions after 40 Ma in the Xining Basin, which may have been responsible for the long-term trend of decreasing chemical weathering during the Eocene.展开更多
The NE-to NNE-striking Tan-Lu Fault Zone(TLFZ) is the largest fault zone in East China, and a typical representative for the circum-Pacific tectonics. Its late Mesozoic evolution resulted from subduction of the Paleo-...The NE-to NNE-striking Tan-Lu Fault Zone(TLFZ) is the largest fault zone in East China, and a typical representative for the circum-Pacific tectonics. Its late Mesozoic evolution resulted from subduction of the Paleo-Pacific Plate,and can be used for indication to the subduction history. The TLFZ reactivated at the end of Middle Jurassic since its origination in Middle Triassic. This phase of sinistral motion can only be recognized along the eastern edge of the Dabie-Sulu orogenis,and indicates initiation of the Paleo-Pacific(Izanagi) Plate subduction beneath the East China continent. After the Late Jurassic standstill, the fault zone experienced intense sinistral faulting again at the beginning of Early Cretaceous under N-S compression that resulted from the NNW-ward, low-angle, high-speed subduction of the Izanagi Plate. It turned into normal faulting in the rest of Early Cretaceous, which was simultaneous with the peak destruction of the North China Craton caused by backarc extension that resulted from rollback of the subducting Izanagi Plate. The TLFZ was subjected to sinistral, transpressive displacement again at the end of Early Cretaceous. This shortening event led to termination of the North China Craton destruction. The fault zone suffered local normal faulting in Late Cretaceous due to the far-field, weak backarc extension. The late Mesozoic evolution of the TLFZ show repeated alternation between the transpressive strike-slip motion and normal faulting. Each of the sinistral faulting event took place in a relatively short period whereas every normal faulting event lasted in a longer period, which are related to the subduction way and history of the Paleo-Pacific Plates.展开更多
文摘The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].
基金Under the auspices of National Key Basic Research Program of China(No.2013CB430401)National Key Research and Development Program of China(No.2016YFC0500404-4)Youth Innovation Promotion Association CAS(No.2017274)
文摘The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data(as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979(116.47 × 10~3 ha) to 2012(2205.65 × 10~3 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13 th Five-Year Fisheries Planning' is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.
文摘Historically Turks had always relied on military power. The culture is rich with martial values to this day. Even each civilian is somewhat soldierly in a sense, in general. Nevertheless, in a more detailed analysis, in some territories of the country, the prestige enjoyed by the military is more intensive than the average, while in some other territories, respect for military people is much below the average tendency. One might infer that in the former category, it is a question of the regions where the inhabitants are mild, soft-spoken, and compatible. They accordingly admire discipline and display obedient attitudes vis-a-vis governmental authority ever since the Ottoman times, merely as a cultural and traditional trait. Those regions are certainly places where military people today are held in high esteem. In such locations, even the ideal profession for a little boy is indoctrinated as a military career, by the whole family or the surrounding social environment. It should be mentioned that in certain cities and towns, a substantial percentage of the population are represented by immigrants, who got re-patriated along the course of the near history, as the former Ottoman Empire began shrinking in territory due to loss of land, during successive wars. The crushing majority of the Muslim Ottoman subjects in those lost territories preferred leaving their property and escaping into the Anatolian mainland, rather than renouncing their belief and assimilating to the new political regime. Having suffered at the hands of foreign powers, those people have also been especially appreciative of the value of their own soldiers. As for the latter category, dislike of discipline and authority can be mainly attributed to the special social structure and historical circumstances.
文摘Since China's reform and accession to the world trade organization (WTO), the international labor division, cooperation, and communication of production have been a direction of the global productivity development. The expansion of the world trade organization and the growth of multinational corporations have promoted China's market economy to head for internationalization; the exchanges of all countries' science and technology, culture, and education have become increasingly frequent and beyond the borders very early, so opening-up has become a world trend. China is playing an important role in this historical process. In this situation, the importance of language translation is increasing day by day, and an unprecedented prosperous situation has especially appeared to the interpretation. In order to accord with this new historical situation, many colleges and universities have set up language translation program and have offered interpretation course. To promote the economic development of China and train more senior interpreters, the studies of interpretation teaching and the improvement of interpretation teaching quality have been particularly important. In this paper, the relationship among memory, note-taking, and psychological factors are analyzed.
基金Great Base Project of National Natural Science Foundation of China (No.49761007 and 49861005) International Science Research As
文摘Through synthetic researches of multi-index geological records of Niya section, which are of high resolution in southern margin of Tarim Basin, this paper has reconstructed the sequences of paleoclimate in this region during historical times (since about 4000a B.P.). During the last 4000 years, the area has experienced alternations of relative cold-moisture and relative warm-dry periods. Three evident cold-moisture periods and three warm-dry periods are identifing. The study shows that the human activities have an intimate relation with the evolution of paleoclimate in the southern Xinjiang. Paleoclimate has played very important role in influencing human being′s agricultural activities.
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In this article the crucial role of the Lutheran Church in Sweden in neighboring Lutheran Danish enemies in the province of Scania into the pseudo-indigenization process of making loyal Swedish citizen after the peace treaty of Roskilde 1658, and more pronounced after 1678, is described and discussed. The process included educational, pedagogical, judicial, liturgical and theological-rhetorical means and had significant, invaluable, and long lasting consequences. The province remains as a part of the Kingdom of Sweden. From a historical perspective, the process was fast and successful, even though some modem historians question the speediness of the process and thereby want to modify the picture of a fast and non-problematic Swedification or pseudo-indigenization process.
文摘A central tenet of coevolutionary theory,including theory of the coevolutionary relationship between brood parasites and their hosts,is that temporal and spatial patterns may reveal important information about ecological and evolutionary dynamics.For instance,level of genetic structure of populations provides important information about the role of genetics and gene ow in determining local patterns of selection on hosts due to parasitism(i.e.,egg rejection) and on parasites due to selection by hosts(i.e.,egg mimicry).Furthermore,abiotic(i.e.,climatic conditions) and biotic(phenotypic characteristics of animals) factors that also vary spatially may directly or indirectly a ect populations of hosts and brood parasites and,therefore,their interaction.By reviewing the literature,we found considerable evidence for an e ect of the spatially and temporally structured abiotic environment on the phenotype of both parasite and host eggs and the degree of mimicry.Moreover,we found examples suggesting that speci c life history characteristics of hosts that vary geographically and/or temporally may a ect the probability of initial colonization of a new host species and the direction and the speed of coevolution.We provide an exhaustive review of studies investigating temporal and spatial patterns of the interaction between brood parasites and their hosts.Such temporal and spatial trends in parasite and host traits are,together with genetic information on rejection and signi cant e ects of gene ow,consistent with coevolutionary dynamics.However,gene ow and changes in the temporal and spatial patterns of abundance of both parasites and hosts may result in frequent cases of counter-intuitive relationships between the phenotype of the parasite and that of the host(i.e.,poor or no mimicry),which may suggest limits to the degree of adaptation.We provide a list of scienti c questions in need of further investigation,concluding that studies of brood parasites and their hosts may play a central role in testing the geographic theory of coevolution and several alternative hypotheses.
文摘CCPIT is a professional promo- tion in international business exchange.We draw this con- clusion not only because of its vast geography coverage by 16 overseas representative offices,50
基金supported by the National Natural Science Foundation of China(Grant No. 30671587)the Programme for Introducing Talents of Discipline to Universities(Grant No.B07045)+1 种基金the Doctorial Innovation Fund of Southwest University(Grant No.Kb2009019)supported by grants from the U.S.National Science Foundation(Grant Nos.0531769, 0531626,and DEB-0212910)
文摘The silkworm,Bombyx mori,played an important role in the old Silk Road that connected ancient Asia and Europe.However,to date,there have been few studies of the origins and domestication of this species using molecular methods.In this study,DNA sequences of mitochondrial and nuclear loci were used to infer the phylogeny and evolutionary history of the domesticated silkworm and its relatives.All of the phylogenetic analyses indicated a close relationship between the domesticated silkworm and the Chinese wild silkworm.Domestication was estimated to have occurred about 4100 years ago(ya),and the radiation of the different geographic strains of B.mori about 2000 ya.The Chinese wild silkworm and the Japanese wild silkworm split about 23600 ya.These estimates are in good agreement with the fossil evidence and historical records.In addition,we show that the domesticated silkworm experienced a population expansion around 1000 ya.The divergence times and the population dynamics of silkworms presented in this study will be useful for studies of lepidopteran phylogenetics,in the genetic analysis of domestic animals,and for understanding the spread of human civilizations.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41430531 & 41690114)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26020201)the International Partnership Program of Chinese Academy of Sciences (Grant No. 131C11KYSB20160061)
文摘The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major advances in the last few decades,the evolutionary history and possible mechanisms of Eocene climate change in the northeastern Tibetan Plateau remain unclear.The Xining Basin in the northeastern Tibetan Plateau contains a continuous sequence of Early to Late Eocene non-marine sediments which provides the opportunity to resolve long-term climate changes during this period. In this study, we report the results of analyses of lithofacies, sediment color and geochemistry of bulk samples collected from the Xijigou section of the Xining Basin. An abrupt lithofacies change between the Early(~52–40 Ma) and Late Eocene(~40–34 Ma) indicates a change in the depositional environment from a shallow lake to a playa lake in response to a significant climatic shift. During ~52–40 Ma,higher values of sediment redness(a*), redness/lightness(a*/L*) and higher modified Chemical Index of Weathering(CIW′)indicate a relatively warm and humid climate, while from ~40–34 Ma the lower values of a*, a*/L*and lower CIW′ imply subhumid to semi-arid climatic conditions. The paleoclimatic records indicate a long-term(~52–34 Ma) trend of decreasing chemical weathering, consistent with global climate change. An abrupt sharp excursion of the proxy records during ~42–40 Ma suggests a relatively brief warm interval, corresponding to the Middle Eocene Climatic Optimum(MECO). We suggest that global cooling substantially reduced humidity in inner Asia, resulting in sub-humid to semi-arid climatic conditions after 40 Ma in the Xining Basin, which may have been responsible for the long-term trend of decreasing chemical weathering during the Eocene.
基金supported by the National Natural Science Foundation of China(Grant Nos.41472186&91414301)the National Key Basic Research Program of China(Grant No.2016YFC0600102)
文摘The NE-to NNE-striking Tan-Lu Fault Zone(TLFZ) is the largest fault zone in East China, and a typical representative for the circum-Pacific tectonics. Its late Mesozoic evolution resulted from subduction of the Paleo-Pacific Plate,and can be used for indication to the subduction history. The TLFZ reactivated at the end of Middle Jurassic since its origination in Middle Triassic. This phase of sinistral motion can only be recognized along the eastern edge of the Dabie-Sulu orogenis,and indicates initiation of the Paleo-Pacific(Izanagi) Plate subduction beneath the East China continent. After the Late Jurassic standstill, the fault zone experienced intense sinistral faulting again at the beginning of Early Cretaceous under N-S compression that resulted from the NNW-ward, low-angle, high-speed subduction of the Izanagi Plate. It turned into normal faulting in the rest of Early Cretaceous, which was simultaneous with the peak destruction of the North China Craton caused by backarc extension that resulted from rollback of the subducting Izanagi Plate. The TLFZ was subjected to sinistral, transpressive displacement again at the end of Early Cretaceous. This shortening event led to termination of the North China Craton destruction. The fault zone suffered local normal faulting in Late Cretaceous due to the far-field, weak backarc extension. The late Mesozoic evolution of the TLFZ show repeated alternation between the transpressive strike-slip motion and normal faulting. Each of the sinistral faulting event took place in a relatively short period whereas every normal faulting event lasted in a longer period, which are related to the subduction way and history of the Paleo-Pacific Plates.