The ultrafast active cavitation imaging(UACI)based on plane wave transmission and delay-and-sum(DAS)beamforming has been developed to monitor cavitation events with a high frame rate.However,DAS beamforming leads to i...The ultrafast active cavitation imaging(UACI)based on plane wave transmission and delay-and-sum(DAS)beamforming has been developed to monitor cavitation events with a high frame rate.However,DAS beamforming leads to images with limited resolution and contrast.In this paper,minimum variance(M V)adaptive beamforming and coherence factor(CF)weighting are combined to achieve an MVCF-based UACI,which can improve the cavitation imaging quality.The detailed algorithm evaluation has been investigated from both simulation and experimental data The simulation data include10point targets and a cyst,while the experimental data are obtained by detecting the dissipation of cavitation bubbles in water excited by a single element transducer with frequency of1.2MHz.The advantages of the proposed methodology as well as the comparison with conventional B-mode,DAS?M V,DAS-CF and MV on the basis of compressive sensing(CS)(called MVCS)beamformers are discussed.The results show that MVCF beamformer has a significant improvement in terms of both resolutions and signal-to-noise ratio(SN R).The MVCF-based UACI has a SNR at21.82dB higher,lateral and axial resolution at2.69times and1.93times?respectively,which were compared with those of B-mode active cavitation mapping.The MVCF-based UACI can be used to image the residual cavitation bubbles with a higher SNR and better spatial resolution展开更多
By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for ...By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Nino-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Nino, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a 'Southern Flood and Northern Drought' pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a 'Northern Flood and Southern Drought' pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over the east of China. The third mode is positively correlated with the tropical SSTA in the Indian Ocean from the spring of preceding year(-1) to the winter of following year(+1), but not related to the ENSO events. The positive SSTA in the South China Sea and the Philippine Sea persists from spring to autumn, leading to weak north-south and land-sea thermal contrasts, which may weaken the intensity of the East Asia summer monsoon. The weakened rainfall over the northern Indian monsoon region may link to the third spatial mode through the 'Silk Road' teleconnection or a part of circumglobal teleconnection (CGT). The physical mechanisms that reveal these linkages remain elusive and invite further investigation.展开更多
Load-Unload Response Ratio (LURR) is a new promising approach to earthquake prediction. In the previous years, a series of successful medium-term predictions have been made for strong earthquakes on the Chinese mainla...Load-Unload Response Ratio (LURR) is a new promising approach to earthquake prediction. In the previous years, a series of successful medium-term predictions have been made for strong earthquakes on the Chinese mainland using this method. In order to investigate whether the LURR method applies to different tectonic regimes, i.e., whether it is universal, the San Andreas Fault and its vicinities are chosen as the study region in this paper. The spatial variation of LURR in the western United States (30°～50°N, 100°～130°W) is studied in detail and the earthquake tendency in this region is discussed based on historic earthquake cases.展开更多
Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford App...Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford Approach(CASA) model to estimate the NPP of plant communities in Hengduan Mountains area of China, and to explore the relationship between NPP and altitude in this region. We examined the mechanisms underlying vegetation growth responses to climate change and quantitatively assessed the effects of ecological protection measures by partitioning the contributions of climate change and human activities to NPP changes. The results demonstrated that: 1) the average total and annual NPP values over the years were 209.15 Tg C and 468.06 g C/(m2·yr), respectively. Their trend increasingly fluctuated, with spatial distribution strongly linked to altitude(i.e., lower and higher NPP in high altitude and low altitude areas, respectively) and 2400 m represented the marginal altitude for vegetation differentiation; 2) areas where climate was the main factor affecting NPP accounted for 18.2% of the total research area, whereas human activities were the primary factor influencing NPP in 81.8% of the total research area, which indicated that human activity was the main force driving changes in NPP. Areas where climatic factors(i.e., temperature and precipitation) were the main driving factors occupied 13.6%(temperature) and 6.0%(precipitation) of the total research area, respectively. Therefore, the effect of temperature on NPP changes was stronger than that of precipitation; and 3) the majority of NPP residuals from 2001 to 2014 were positive, with human activities playing an active role in determining regional vegetation growth, possibly due to the return of farmland back to forest and natural forest protection. However, this positive trend is decreasing. This clearly shows the periodical nature of ecological projects and a lack of long-term effectiveness.展开更多
This paper aims at investigating architectural and urban heritage from the sociocultural point of view, which stands on the human asset of traditional sites such as the hawari of old Cairo. It analyzes the social prac...This paper aims at investigating architectural and urban heritage from the sociocultural point of view, which stands on the human asset of traditional sites such as the hawari of old Cairo. It analyzes the social practice of everyday life in one of the oldest Cairene hawari, Haret al Darb al Asfar. The focus is on architectural and spatial organization of outdoor and indoor spaces that coordinate the spatial practices of local community. A daily monitoring of people＇s activities and interviews was conducted in an investigation of how local people perceive their built environment between the house＇s interior and the outdoor shared space. It emerges that people construct their own field of private spheres according to complex patterns of daily activities that are not in line with the classical segregation between private and public in Islamic cities. This paper reports that the harah is basically a construct of social spheres that are organized spatially by the flexible development of individual buildings over time and in response to changes in individuals＇ needs and capabilities. In order to achieve sustainability in old urban quarters, the paper concludes, the focus should be directed towards the local organization of activities and a comprehensive upgrading of deteriorating buildings to match the changing needs of current population.展开更多
The term geopoetics has a wide interpretation. It is defined as a project of the cultural activity aimed at creating and changing territorial myths and research path, which considers the interaction between literary c...The term geopoetics has a wide interpretation. It is defined as a project of the cultural activity aimed at creating and changing territorial myths and research path, which considers the interaction between literary creativity and geographical space. Defining this term, it is possible to introduce a geopoetical analysis diagram based on three interconnected positions： the writer＇s personality, the universe of an artwork and its characters. The Last Novik--A historical novel by Lazhechnikov analysis example presented on a diagram reveals the relationship between time and space in the literary work, as well as the author＇s interaction with the described events.展开更多
A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotrans...A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.展开更多
Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper ...Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.展开更多
Temporal and spatial evolution of proto-basins and magmatism in the North China Craton might provide information of its destruction.Overall,the destruction of the North China Craton is a heterogeneous process of botto...Temporal and spatial evolution of proto-basins and magmatism in the North China Craton might provide information of its destruction.Overall,the destruction of the North China Craton is a heterogeneous process of bottom upward and from margin toward interior,related to multiple interactions between the craton and its surrounding plates.The interior of craton would be initially destructed during the Early-Middle Jurassic.Subduction of the Paleo-Asian Ocean Plate may have destructed the northern margin of the North China Craton.Collision of the Yangtze Plate with the North China Craton is significant for the magmatic and tectonic activities during the Late Triassic-Middle Jurassic.Subductions of the Izanagi and Paleo-Pacific plates lead to the ultimate destruction of the North China Craton.Temporal and spatial evolution of the proto-basins and related magmatism in the North China Craton indicate that the dominant mechanism of the cratonic destruction may be thermal mechanical-chemical erosion.展开更多
The growth rate of solar activity in the early phase of a solar cycle has been known to be well correlated with the subsequent amplitude （solar maximum）. It provides very useful information for a new solar cycle as ...The growth rate of solar activity in the early phase of a solar cycle has been known to be well correlated with the subsequent amplitude （solar maximum）. It provides very useful information for a new solar cycle as its variation reflects the temporal evolution of the dynamic process of solar magnetic activities from the initial phase to the peak phase of the cycle. The correlation coefficient between the solar maximum （Rmax） and the rising rate （βa） at Am months after the solar minimum （Rmin） is studied and shown to increase as the cycle progresses with an inflection point （r = 0.83） at about Am = 20 months. The prediction error of Rmax based on βa is found within estimation at the 90% level of confidence and the relative prediction error will be less than 20% when Am ≥ 20. From the above relationship, the current cycle （24） is preliminarily predicted to peak around October, 2013 with a size of Rmax = 84 ＋ 33 at the 90% level of confidence.展开更多
Key Biodiversity Areas(KBAs)are ecological conservation priorities proposed by IUCN and widely recognized by most countries.Evaluating the changes in the ecological characteristics in KBAs is important for biodiversit...Key Biodiversity Areas(KBAs)are ecological conservation priorities proposed by IUCN and widely recognized by most countries.Evaluating the changes in the ecological characteristics in KBAs is important for biodiversity conservation and the construction of Protected Areas(PAs).There are various ecosystem types in the Belt and Road Initiative(BRI)region,which has an extremely high value of biodiversity conservation,and the KBAs should be the prime targets of ecological protection efforts.Using the data of land cover,NDVI and Nighttime Light(NTL),we analyzed the ecological conditions of the KBAs in the BRI region,and their temporal and spatial variations,from the perspectives of vegetation coverage and human activities.The conclusions are:(1)There is generally no significant difference in the land cover of the KBAs,among which forest,wilderness and grassland are the main types;(2)The NDVI of the KBAs showed an increase,indicating that the vegetation was gradually improving,while a few KBAs presenting vegetation degradation were mainly distributed in the Indochina Peninsula,Qinghai-Tibet Plateau and Central and Western Asia;and(3)The NTL in the KBAs was very low,indicating that the human pressure on the natural ecosystems was limited,and only a few KBAs distributed in Central and Eastern Europe,India,and the Indochina Peninsula have high human activity intensity which also showed an increase.This study emphasizes that we should make full use of the biome succession law,and limit the interference of human activities on natural ecosystems for ecological protection of the KBAs,so as to continuously make new breakthroughs in the construction of Protected Areas(PA)in the BRI region.展开更多
There is growing evidence that individual animals show consistent differences in behavior. For example, individual threespined stickleback fish differ in how they react to predators and how aggressive they are during ...There is growing evidence that individual animals show consistent differences in behavior. For example, individual threespined stickleback fish differ in how they react to predators and how aggressive they are during social interactions with con- specifics. A relatively unexplored but potentially important axis of variation is parental behavior. In sticklebacks, fathers provide all of the parental care that is necessary for offspring survival; therefore paternal care is directly tied to fitness. In this study, we assessed whether individual male sticklebacks differ consistently from each other in parental behavior. We recorded visits to nest, total time fanning, and activity levels of 11 individual males every day throughout one clutch, and then allowed the males to breed again. Half of the males were exposed to predation risk while parenting during the first clutch, and the other half of the males ex- perienced predation risk during the second clutch. We detected dranlatic temporal changes in parental behaviors over the course of the clutch： for example, total time fanning increased six-fold prior to eggs hatching, then decreased to approximately zero. De- spite these temporal changes, males retained their individually-distinctive parenting styles within a clutch that could not be ex- plained by differences in body size or egg mass. Moreover, individual differences in parenting were maintained when males re- produced for a second time. Males that were exposed to simulated predation risk briefly decreased fanning and increased activity levels. Altogether, these results show that individual sticklebacks consistently differ from each other in how they behave as parents [Current Zoology 58 （1）： 45-52, 2012].展开更多
基金National Natural Science Foundation of China(No.11604305)Key Research and Development Projects from Ministry of Science and Technology of the People’s Republic of China(No.2016YFC0101605)
文摘The ultrafast active cavitation imaging(UACI)based on plane wave transmission and delay-and-sum(DAS)beamforming has been developed to monitor cavitation events with a high frame rate.However,DAS beamforming leads to images with limited resolution and contrast.In this paper,minimum variance(M V)adaptive beamforming and coherence factor(CF)weighting are combined to achieve an MVCF-based UACI,which can improve the cavitation imaging quality.The detailed algorithm evaluation has been investigated from both simulation and experimental data The simulation data include10point targets and a cyst,while the experimental data are obtained by detecting the dissipation of cavitation bubbles in water excited by a single element transducer with frequency of1.2MHz.The advantages of the proposed methodology as well as the comparison with conventional B-mode,DAS?M V,DAS-CF and MV on the basis of compressive sensing(CS)(called MVCS)beamformers are discussed.The results show that MVCF beamformer has a significant improvement in terms of both resolutions and signal-to-noise ratio(SN R).The MVCF-based UACI has a SNR at21.82dB higher,lateral and axial resolution at2.69times and1.93times?respectively,which were compared with those of B-mode active cavitation mapping.The MVCF-based UACI can be used to image the residual cavitation bubbles with a higher SNR and better spatial resolution
基金supported by the National Basic Research Program of China (973 Program) (No. 2012CB955604)the National Natural Science Foundation of China (Nos. 40975038, 40830106)+1 种基金the CMA Program (GYHY200906008)the 111 Project (B07036)
文摘By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Nino-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Nino, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a 'Southern Flood and Northern Drought' pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a 'Northern Flood and Southern Drought' pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over the east of China. The third mode is positively correlated with the tropical SSTA in the Indian Ocean from the spring of preceding year(-1) to the winter of following year(+1), but not related to the ENSO events. The positive SSTA in the South China Sea and the Philippine Sea persists from spring to autumn, leading to weak north-south and land-sea thermal contrasts, which may weaken the intensity of the East Asia summer monsoon. The weakened rainfall over the northern Indian monsoon region may link to the third spatial mode through the 'Silk Road' teleconnection or a part of circumglobal teleconnection (CGT). The physical mechanisms that reveal these linkages remain elusive and invite further investigation.
文摘Load-Unload Response Ratio (LURR) is a new promising approach to earthquake prediction. In the previous years, a series of successful medium-term predictions have been made for strong earthquakes on the Chinese mainland using this method. In order to investigate whether the LURR method applies to different tectonic regimes, i.e., whether it is universal, the San Andreas Fault and its vicinities are chosen as the study region in this paper. The spatial variation of LURR in the western United States (30°～50°N, 100°～130°W) is studied in detail and the earthquake tendency in this region is discussed based on historic earthquake cases.
基金Under the auspices of National Key Basic Research Program of China(No.2015CB452706)National Natural Science Foundation of China(No.41401198,41571527)+1 种基金Youth Talent Team Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(No.SDSQB-2015-01)Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2016332)
文摘Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford Approach(CASA) model to estimate the NPP of plant communities in Hengduan Mountains area of China, and to explore the relationship between NPP and altitude in this region. We examined the mechanisms underlying vegetation growth responses to climate change and quantitatively assessed the effects of ecological protection measures by partitioning the contributions of climate change and human activities to NPP changes. The results demonstrated that: 1) the average total and annual NPP values over the years were 209.15 Tg C and 468.06 g C/(m2·yr), respectively. Their trend increasingly fluctuated, with spatial distribution strongly linked to altitude(i.e., lower and higher NPP in high altitude and low altitude areas, respectively) and 2400 m represented the marginal altitude for vegetation differentiation; 2) areas where climate was the main factor affecting NPP accounted for 18.2% of the total research area, whereas human activities were the primary factor influencing NPP in 81.8% of the total research area, which indicated that human activity was the main force driving changes in NPP. Areas where climatic factors(i.e., temperature and precipitation) were the main driving factors occupied 13.6%(temperature) and 6.0%(precipitation) of the total research area, respectively. Therefore, the effect of temperature on NPP changes was stronger than that of precipitation; and 3) the majority of NPP residuals from 2001 to 2014 were positive, with human activities playing an active role in determining regional vegetation growth, possibly due to the return of farmland back to forest and natural forest protection. However, this positive trend is decreasing. This clearly shows the periodical nature of ecological projects and a lack of long-term effectiveness.
文摘This paper aims at investigating architectural and urban heritage from the sociocultural point of view, which stands on the human asset of traditional sites such as the hawari of old Cairo. It analyzes the social practice of everyday life in one of the oldest Cairene hawari, Haret al Darb al Asfar. The focus is on architectural and spatial organization of outdoor and indoor spaces that coordinate the spatial practices of local community. A daily monitoring of people＇s activities and interviews was conducted in an investigation of how local people perceive their built environment between the house＇s interior and the outdoor shared space. It emerges that people construct their own field of private spheres according to complex patterns of daily activities that are not in line with the classical segregation between private and public in Islamic cities. This paper reports that the harah is basically a construct of social spheres that are organized spatially by the flexible development of individual buildings over time and in response to changes in individuals＇ needs and capabilities. In order to achieve sustainability in old urban quarters, the paper concludes, the focus should be directed towards the local organization of activities and a comprehensive upgrading of deteriorating buildings to match the changing needs of current population.
文摘The term geopoetics has a wide interpretation. It is defined as a project of the cultural activity aimed at creating and changing territorial myths and research path, which considers the interaction between literary creativity and geographical space. Defining this term, it is possible to introduce a geopoetical analysis diagram based on three interconnected positions： the writer＇s personality, the universe of an artwork and its characters. The Last Novik--A historical novel by Lazhechnikov analysis example presented on a diagram reveals the relationship between time and space in the literary work, as well as the author＇s interaction with the described events.
基金partially supported and funded by Chongqing Research Program of Basic Research and Frontier Technology (Grant No. cstc2017jcyj B0317)Chongqing University Innovation Team Building Plan (Grant No. CXTDX201601017)Science and Technology Project of Chongqing Municipal Education Commission (Grant No. KJ1738462)
文摘A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.
基金supported by the National Science and Technology Program of China Earthquake Administration (No. 2006BAC01B02-01-05)Anhui Provincial Science and Technique Foundation (No. 08010302204)Joint Earthquake Science Fundation (A08077)
文摘Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.
基金supported by National Natural Science Foundation of China(Grant Nos.41003017,41273042,70914001)Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KZCX1-YW-15-1)
文摘Temporal and spatial evolution of proto-basins and magmatism in the North China Craton might provide information of its destruction.Overall,the destruction of the North China Craton is a heterogeneous process of bottom upward and from margin toward interior,related to multiple interactions between the craton and its surrounding plates.The interior of craton would be initially destructed during the Early-Middle Jurassic.Subduction of the Paleo-Asian Ocean Plate may have destructed the northern margin of the North China Craton.Collision of the Yangtze Plate with the North China Craton is significant for the magmatic and tectonic activities during the Late Triassic-Middle Jurassic.Subductions of the Izanagi and Paleo-Pacific plates lead to the ultimate destruction of the North China Craton.Temporal and spatial evolution of the proto-basins and related magmatism in the North China Craton indicate that the dominant mechanism of the cratonic destruction may be thermal mechanical-chemical erosion.
基金supported by the National Natural Science Foundation of China (Grant Nos.10973020,40890161 and 10921303)the National Basic Research Program of China (Grant No.2011CB811406)the China Meteorological Administration (Grant No.GYHY201106011)
文摘The growth rate of solar activity in the early phase of a solar cycle has been known to be well correlated with the subsequent amplitude （solar maximum）. It provides very useful information for a new solar cycle as its variation reflects the temporal evolution of the dynamic process of solar magnetic activities from the initial phase to the peak phase of the cycle. The correlation coefficient between the solar maximum （Rmax） and the rising rate （βa） at Am months after the solar minimum （Rmin） is studied and shown to increase as the cycle progresses with an inflection point （r = 0.83） at about Am = 20 months. The prediction error of Rmax based on βa is found within estimation at the 90% level of confidence and the relative prediction error will be less than 20% when Am ≥ 20. From the above relationship, the current cycle （24） is preliminarily predicted to peak around October, 2013 with a size of Rmax = 84 ＋ 33 at the 90% level of confidence.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20010202)The National Key Research and Development Program of China(2016YFC0503505)。
文摘Key Biodiversity Areas(KBAs)are ecological conservation priorities proposed by IUCN and widely recognized by most countries.Evaluating the changes in the ecological characteristics in KBAs is important for biodiversity conservation and the construction of Protected Areas(PAs).There are various ecosystem types in the Belt and Road Initiative(BRI)region,which has an extremely high value of biodiversity conservation,and the KBAs should be the prime targets of ecological protection efforts.Using the data of land cover,NDVI and Nighttime Light(NTL),we analyzed the ecological conditions of the KBAs in the BRI region,and their temporal and spatial variations,from the perspectives of vegetation coverage and human activities.The conclusions are:(1)There is generally no significant difference in the land cover of the KBAs,among which forest,wilderness and grassland are the main types;(2)The NDVI of the KBAs showed an increase,indicating that the vegetation was gradually improving,while a few KBAs presenting vegetation degradation were mainly distributed in the Indochina Peninsula,Qinghai-Tibet Plateau and Central and Western Asia;and(3)The NTL in the KBAs was very low,indicating that the human pressure on the natural ecosystems was limited,and only a few KBAs distributed in Central and Eastern Europe,India,and the Indochina Peninsula have high human activity intensity which also showed an increase.This study emphasizes that we should make full use of the biome succession law,and limit the interference of human activities on natural ecosystems for ecological protection of the KBAs,so as to continuously make new breakthroughs in the construction of Protected Areas(PA)in the BRI region.
文摘There is growing evidence that individual animals show consistent differences in behavior. For example, individual threespined stickleback fish differ in how they react to predators and how aggressive they are during social interactions with con- specifics. A relatively unexplored but potentially important axis of variation is parental behavior. In sticklebacks, fathers provide all of the parental care that is necessary for offspring survival; therefore paternal care is directly tied to fitness. In this study, we assessed whether individual male sticklebacks differ consistently from each other in parental behavior. We recorded visits to nest, total time fanning, and activity levels of 11 individual males every day throughout one clutch, and then allowed the males to breed again. Half of the males were exposed to predation risk while parenting during the first clutch, and the other half of the males ex- perienced predation risk during the second clutch. We detected dranlatic temporal changes in parental behaviors over the course of the clutch： for example, total time fanning increased six-fold prior to eggs hatching, then decreased to approximately zero. De- spite these temporal changes, males retained their individually-distinctive parenting styles within a clutch that could not be ex- plained by differences in body size or egg mass. Moreover, individual differences in parenting were maintained when males re- produced for a second time. Males that were exposed to simulated predation risk briefly decreased fanning and increased activity levels. Altogether, these results show that individual sticklebacks consistently differ from each other in how they behave as parents [Current Zoology 58 （1）： 45-52, 2012].
