The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central ...The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation.展开更多
The State Intellectual Poperty Office has announcedan amendment to Sec.5,Paragrph 4.2.of Chapter 7 ofExamination Guidelines.According to the newregulations,for making a respon to an office actionduring the prosecution...The State Intellectual Poperty Office has announcedan amendment to Sec.5,Paragrph 4.2.of Chapter 7 ofExamination Guidelines.According to the newregulations,for making a respon to an office actionduring the prosecution of a patent application,only a firstrequest for a two-month extension of time can be basicallyallowed upon payment of official fee of RMB300(aboutUSD36).For further extension after the first one,onlyanother request for one or two months,at most twomonths,would be possibly petitioned together with a copyof the client’s instructions of the further extension and展开更多
Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glac...Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glacier changes are also of great significance to the regulation of regional water resources.This study selected the Hala Lake Basin in the northeastern Qinhai-Tibet Plateau as a study area,and examined the relationships between the temporal and spatial change of glaciers in the northeastern Qinghai-Tibet Plateau and climate change based on remote sensing imagery,climatological data,and topographic data during the past 30 years.Results showed that glacier area in the Hala Lake basin fluctuated and decreased from106.24 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·yr-1.The number of glacier patches,mean patch area,and largest patch index all decreased from 1986 to 2015,while the splitting index increased from 1986 to 2015,indicating that the landscape fragmentation of glacier in the Hala Lake Basin was increasing significantly during the study period.Glacier area change was mainly concentrated in the slopes>25°with an altitude of 4500-5000 m,and the retreating rate of glacier of sunny slope was obviously higher than that of shady slope.Geometric center of glacier in the basin moved from southwest to northeast towards high altitude.Results of the response of glacier extent to climate change showed that temperature was the dominant factor affecting glacier area dynamic change in the Hala Lake Basin.It is predicted that in future several years,the glacier area will decrease and fragment continually as a result of global warming on the Tibetan Plateau.展开更多
Background: Purpose of this study was to evaluate various parameters of meningioma after surgical treatment and analyze predictive factors for recurrence. Methods: During 1992-2007, 353 patients were operated for intr...Background: Purpose of this study was to evaluate various parameters of meningioma after surgical treatment and analyze predictive factors for recurrence. Methods: During 1992-2007, 353 patients were operated for intracranial meningioma in our department. They were followed since, and related data were combined with parameters such as tumor histology (WHO system), tumor location and the extent of tumor resection (Simpson’s scale). The results were analyzed with respect to tumor reappearance. This study was approved by the ethics committee of G. Papanikolaou Hospital. Results: The mean follow up period was 6.45 years. The overall percentage of recurrence was 21.52%. Grade 1 meningiomas (benign) recurred at a rate of 19.1%, grade 2 tumors (atypical) showed 41.7% rate of recurrence and grade 3 meningiomas (malignant) recurred at a rate of 75%. Tumor histopathology was not significant to recurrence (p > 0.001). The location of meningiomas was not found to be significant to recurrence (p > 0.001). Complete tumor resection was accomplished in 269 patients (76.2%). Incomplete resection (Simpson grades 2-5) took place in 84 cases (23.8%). The recurrence rate after complete resection was 13.8%, while the rate for cases with incomplete resection was 46.7%. The extent of removal was significantly associated with recurrence (p < 0.001). Conclusions: Tumor recurrence was observed at 21.5% of patients in our series of intracranial meningioma surgery. The rate of recurrence was related primarily to the extent of surgical removal. Neither tumor site, nor tumor histology were predictive factors for recurrence (ma-lignant meningiomas excluded).展开更多
Bangladesh is a land of wetlands. Basically, most of them are freshwater wetlands and have great influence on the primary economic activities such as agriculture and fisheries of the country. Due to its important role...Bangladesh is a land of wetlands. Basically, most of them are freshwater wetlands and have great influence on the primary economic activities such as agriculture and fisheries of the country. Due to its important role in the harmonizing ecosystem, wetlands demand much attention as a significant part of our environment. Matasagar and Sukhsagar are very important historical wetlands of Bangladesh. But those are endangered today due to lack of public awareness of the dangers of their activities to the environment and unbridled profit making activities of the commercial users of the wetlands. Comparisons of maps and Google images from 1933 to present have shown that the forest areas of the wetlands have been progressively destroyed, and these have greatly affected the biodiversity of these areas mentioned. GIS (Geographic Information System) and remote sensing techniques are used to identify the changes in the aerial extent of those wetlands. This study also tried to explore present environmental conditions by in-situ observation. This is high time;some serious steps should be taken to ensure the conservation and preservation of these areas mentioned.展开更多
1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Pal...1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Paleogene,under the control of the planetary winds and the north subtropical high pressure belts,a ribbon arid。展开更多
Previous studies have shown evidence of atmospheric extratropical wave trains modulating sea ice area in the Weddell and Amundsen/Bellingshausen seas on intraseasonal time-scales(20–100 d). Here we investigate mechan...Previous studies have shown evidence of atmospheric extratropical wave trains modulating sea ice area in the Weddell and Amundsen/Bellingshausen seas on intraseasonal time-scales(20–100 d). Here we investigate mechanisms relating intraseasonal extreme sea ice extent and Ekman layer dynamics with emphasis on the Weddell Sea. This study extends from 1989 to 2013 and focuses on the winter season. Wind stress τ is calculated with winds from the Climate Forecast System reanalysis(CFSR) to evaluate momentum transfer between the atmosphere and the Ekman layer. Lag-composites of the anomalies of Ekman transport and the Ekman pumping indicate that divergence of mass in the Ekman layer and upwelling lead the occurrence of extreme sea ice contraction on intraseasonal time-scales in the Weddell Sea. Opposite conditions(i.e., convergence of the mass and downwelling) lead extreme sea ice expansion on intraseasonal time-scales. This study suggests that the Ekman pumping resulting from the anomalous wind stress on intraseasonal time-scales can transport these warmer waters to the surface contributing to sea ice melting. Additionally, high resolution sea ice fraction and ocean currents obtained from satellite and in situ data are used to investigate in detail mechanisms associated with persistent extreme sea ice expansion and contraction on intraseasonal time-scales. These case studies reveal that atmospheric circumpolar waves on intraseasonal time-scales can induce contrasting anomalies of about ±20% in sea ice concentration at the Weddell and western Antarctica Peninsula margins within less than 30 d. This study shows that extreme anomalies in sea ice may lag between 5–25 d(1–5 pentads) the ocean-atmospheric forcing on intraseasonal time-scales.展开更多
The mathematical model of peripheral twist extent(PTE) length was set up by studying the kinematics anddynamics of the yarn in rotor groove. The value of PTElength was calculated by using numerical method, andthe fact...The mathematical model of peripheral twist extent(PTE) length was set up by studying the kinematics anddynamics of the yarn in rotor groove. The value of PTElength was calculated by using numerical method, andthe factors affecting the PTE length were also discussed.The results show that the theoretical predicted value ofPTE length seems to be consistent with the measured val-ue. The yarn linear density and rotor speed have re-markable effects on PTE length. The parameters includ-展开更多
<strong>Background: </strong>Given the increase in the numbers of expatriates in Saudi Arabia and the shortage of information about expatriates’ oral health and periodontal disease severity and progressio...<strong>Background: </strong>Given the increase in the numbers of expatriates in Saudi Arabia and the shortage of information about expatriates’ oral health and periodontal disease severity and progression. <strong>Objectives: </strong>This study aimed to evaluate the effects of the racial differences on oral health and periodontal disease extent, staging, and grading among the multi-ethnic expatriates in the Aseer region, Saudi Arabia. <strong>Materials and Methods:</strong> This cross-sectional study was carried out on 300 expatriates in Aseer region, Saudi Arabia. They were divided into three equal racial different groups (n = 100), Arabs (AR), Asians (AS), and Africans (AF). The interviews of all participants were completed then the clinical examinations of periodontal diseases extent, staging, and grading parameters were performed. Statistical analysis was done by ANOVA test, Tukey’s test, and Chi-square test. The statistical significance level was determined at p < 0.05. <strong>Results: </strong>There were statistically significant differences in the comparison between the three ethnic/racial groups in clinical parameters except in GBI, PCR, FI, TFO, and BC, where there were no statistically significant differences in the comparison between the three ethnic/racial groups. There were differences associated with age, gender, smoking, and diabetes, without statistically significant differences among the three racial groups.<strong> Conclusion:</strong> We concluded that most participants in this study had a generalized severe grade 4 plaque-induced gingivitis and localized periodontitis stage III grade B.展开更多
Recently the explored reserves submitted in the oil field mainly situate at the end of deposit in delta front area. During the exploitation and production, problems mainly show on lithologic deposit, for example, rese...Recently the explored reserves submitted in the oil field mainly situate at the end of deposit in delta front area. During the exploitation and production, problems mainly show on lithologic deposit, for example, reserves are low and difficulty of producing is huge. Based on results of sand body dissection of dense well network of developed oil deposit, and combined with explored reserves, this article researches a relation between extent of well control and reserves precision of explored reserves of lithologic deposit in delta front area by well diluted method. This article has significant influence on objectively understanding our unexploited展开更多
Education is to learn or to gain knowledge of something through being taught by others or through self-learning. The two most important words about education are teaching and learning. By definition, teachers are lead...Education is to learn or to gain knowledge of something through being taught by others or through self-learning. The two most important words about education are teaching and learning. By definition, teachers are leaders, and to put it simply leaders lead. Teachers lead their students along the path of knowledge. As for students, they who can be equipped with academic knowledge and a set of practical skills can be useful members of society and make a contribution to the economic development of a nation and even the world. In this sense, we should keep in mind that to consistently improve the quality of education is to promise a bright future for the nation.展开更多
A sea ice extent retrieval algorithm over the polar area based on scatterometer data of HY-2A satellite has been established.Four parameters are used for distinguishing between sea ice and ocean with Fisher's line...A sea ice extent retrieval algorithm over the polar area based on scatterometer data of HY-2A satellite has been established.Four parameters are used for distinguishing between sea ice and ocean with Fisher's linear discriminant analysis method.The method is used to generate polar sea ice extent maps of the Arctic and Antarctic regions of the full 2013–2014 from the scatterometer aboard HY-2A(HY-2A-SCAT) backscatter data.The time series of the ice mapped imagery shows ice edge evolution and indicates a similar seasonal change trend with total ice area from DMSP-F17 Special Sensor Microwave Imager/Sounder(SSMIS) sea ice concentration data.For both hemispheres,the HY-2A-SCAT extent correlates very well with SSMIS 15% extent for the whole year period.Compared with Synthetic Aperture Radar(SAR) imagery,the HY-2A-SCAT ice extent shows good correlation with the Sentinel-1 SAR ice edge.Over some ice edge area,the difference is very evident because sea ice edges can be very dynamic and move several kilometers in a single day.展开更多
Satellite records show the minimum Arctic sea ice extents(SIEs) were observed in the Septembers of 2007 and2012, but the spatial distributions of sea ice concentration reduction in these two years were quite different...Satellite records show the minimum Arctic sea ice extents(SIEs) were observed in the Septembers of 2007 and2012, but the spatial distributions of sea ice concentration reduction in these two years were quite different.Atmospheric circulation pattern and the upper-ocean state in summer were investigated to explain the difference.By employing the ice-temperature and ice-specific humidity(SH) positive feedbacks in the Arctic Ocean, this paper shows that in 2007 and 2012 the higher surface air temperature(SAT) and sea level pressure(SLP)accompanied by more surface SH and higher sea surface temperature(SST), as a consequence, the strengthened poleward wind was favorable for melting summer Arctic sea ice in different regions in these two years. SAT was the dominant factor influencing the distribution of Arctic sea ice melting. The correlation coefficient is –0.84 between SAT anomalies in summer and the Arctic SIE anomalies in autumn. The increase SAT in different regions in the summers of 2007 and 2012 corresponded to a quicker melting of sea ice in the Arctic. The SLP and related wind were promoting factors connected with SAT. Strengthening poleward winds brought warm moist air to the Arctic and accelerated the melting of sea ice in different regions in the summers of 2007 and 2012. Associated with the rising air temperature, the higher surface SH and SST also played a positive role in reducing summer Arctic sea ice in different regions in these two years, which form two positive feedbacks mechanism.展开更多
The spatial database management system of China geological survey extent is a social service system. Its aim is to help the government and the whole social public to expediently use the spatial database, such as query...The spatial database management system of China geological survey extent is a social service system. Its aim is to help the government and the whole social public to expediently use the spatial database, such as querying, indexing, mapping and product outputting. The management system has been developed based on MAPGIS6.x SDK and Visual C++, considering the spatial database contents and structure and the requirements of users. This paper introduces the software structure, the data flow chart and some key techniques of software development.展开更多
Studying the relationship between climate factors and soil organic carbon(SOC) is vitally important. However, how SOC responses to climate(temperature and precipitation) at cohesive extents is poorly studied. Two tran...Studying the relationship between climate factors and soil organic carbon(SOC) is vitally important. However, how SOC responses to climate(temperature and precipitation) at cohesive extents is poorly studied. Two transects of approximately the same length(transect P and transect T) were selected to examine the variation of SOC content in relation to mean annual temperature(MAT) and mean annual precipitation(MAP). The coefficients of partial correlation between SOC density and MAT(Rt) and MAP(Rp) were determined to quantify the relationships between SOC density and the two climate factors. The results indicated that for transect T, Rt was statistically significant once the extent level was greater than or equal to two fundamental extent units, while for transect P, Rp showed statistical significance only at extent levels which were greater than two fundamental extent units. At the same extent levels but in different transects, Rts exhibited no zonal difference, but Rps did once the extent level was greater than two fundamental extent units. Therefore, to study the relationship between SOC density and different climate factors, different minimum extent levels should be examined. The results of this paper could deepen the understanding of the impacts that SOC pool has on terrestrial ecosystem and global carbon cycling.展开更多
The interannual variability of the boreal winter Hadley circulation extents during the period of 1979e2014 and its links to El Ni^no-Southern Oscillation(ENSO) were investigated by using reanalysis datasets. Results s...The interannual variability of the boreal winter Hadley circulation extents during the period of 1979e2014 and its links to El Ni^no-Southern Oscillation(ENSO) were investigated by using reanalysis datasets. Results showed that the El Ni^no(La Ni^na) events can induce the shrinking(expansion) of Hadley circulation extent in the Southern Hemisphere. For the Northern Hemisphere, El Ni^no(La Ni^na) mainly leads to shrinking(expansion) of the Hadley circulation extent in the middle and lower troposphere and expansion(shrinking) of the Hadley circulation extent in the upper troposphere. The ENSO associated meridional temperature gradients have close relationship with the Hadley circulation extents in both Hemispheres. But in the Northern Hemisphere, the ENSO associated eddy momentum flux divergence plays more important role in affecting the Hadley circulation extent than the meridional temperature gradient because of the small local Rossby number. In the Southern Hemisphere, as the ENSO induced eddy momentum flux divergence is small, the meridional temperature gradient dominates the change of the Hadley circulation extent.展开更多
文摘The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation.
文摘The State Intellectual Poperty Office has announcedan amendment to Sec.5,Paragrph 4.2.of Chapter 7 ofExamination Guidelines.According to the newregulations,for making a respon to an office actionduring the prosecution of a patent application,only a firstrequest for a two-month extension of time can be basicallyallowed upon payment of official fee of RMB300(aboutUSD36).For further extension after the first one,onlyanother request for one or two months,at most twomonths,would be possibly petitioned together with a copyof the client’s instructions of the further extension and
基金supported by the National Science Foundation of China (41730854, 41877157, 41530854)the Project supported by State Key Laboratory of Loess and Quaternary Geology (SKLLQG1604)+2 种基金the Project supported by State Key Laboratory of Earth Surface Processes and Resource Ecology (2017-KF-15)the Project of Shandong Province Higher Educational Science and Technology Program (J17KA192)the National Key Research and Development Plan of Shandong Province (2018GSF117021)
文摘Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glacier changes are also of great significance to the regulation of regional water resources.This study selected the Hala Lake Basin in the northeastern Qinhai-Tibet Plateau as a study area,and examined the relationships between the temporal and spatial change of glaciers in the northeastern Qinghai-Tibet Plateau and climate change based on remote sensing imagery,climatological data,and topographic data during the past 30 years.Results showed that glacier area in the Hala Lake basin fluctuated and decreased from106.24 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·yr-1.The number of glacier patches,mean patch area,and largest patch index all decreased from 1986 to 2015,while the splitting index increased from 1986 to 2015,indicating that the landscape fragmentation of glacier in the Hala Lake Basin was increasing significantly during the study period.Glacier area change was mainly concentrated in the slopes>25°with an altitude of 4500-5000 m,and the retreating rate of glacier of sunny slope was obviously higher than that of shady slope.Geometric center of glacier in the basin moved from southwest to northeast towards high altitude.Results of the response of glacier extent to climate change showed that temperature was the dominant factor affecting glacier area dynamic change in the Hala Lake Basin.It is predicted that in future several years,the glacier area will decrease and fragment continually as a result of global warming on the Tibetan Plateau.
文摘Background: Purpose of this study was to evaluate various parameters of meningioma after surgical treatment and analyze predictive factors for recurrence. Methods: During 1992-2007, 353 patients were operated for intracranial meningioma in our department. They were followed since, and related data were combined with parameters such as tumor histology (WHO system), tumor location and the extent of tumor resection (Simpson’s scale). The results were analyzed with respect to tumor reappearance. This study was approved by the ethics committee of G. Papanikolaou Hospital. Results: The mean follow up period was 6.45 years. The overall percentage of recurrence was 21.52%. Grade 1 meningiomas (benign) recurred at a rate of 19.1%, grade 2 tumors (atypical) showed 41.7% rate of recurrence and grade 3 meningiomas (malignant) recurred at a rate of 75%. Tumor histopathology was not significant to recurrence (p > 0.001). The location of meningiomas was not found to be significant to recurrence (p > 0.001). Complete tumor resection was accomplished in 269 patients (76.2%). Incomplete resection (Simpson grades 2-5) took place in 84 cases (23.8%). The recurrence rate after complete resection was 13.8%, while the rate for cases with incomplete resection was 46.7%. The extent of removal was significantly associated with recurrence (p < 0.001). Conclusions: Tumor recurrence was observed at 21.5% of patients in our series of intracranial meningioma surgery. The rate of recurrence was related primarily to the extent of surgical removal. Neither tumor site, nor tumor histology were predictive factors for recurrence (ma-lignant meningiomas excluded).
文摘Bangladesh is a land of wetlands. Basically, most of them are freshwater wetlands and have great influence on the primary economic activities such as agriculture and fisheries of the country. Due to its important role in the harmonizing ecosystem, wetlands demand much attention as a significant part of our environment. Matasagar and Sukhsagar are very important historical wetlands of Bangladesh. But those are endangered today due to lack of public awareness of the dangers of their activities to the environment and unbridled profit making activities of the commercial users of the wetlands. Comparisons of maps and Google images from 1933 to present have shown that the forest areas of the wetlands have been progressively destroyed, and these have greatly affected the biodiversity of these areas mentioned. GIS (Geographic Information System) and remote sensing techniques are used to identify the changes in the aerial extent of those wetlands. This study also tried to explore present environmental conditions by in-situ observation. This is high time;some serious steps should be taken to ensure the conservation and preservation of these areas mentioned.
文摘1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Paleogene,under the control of the planetary winds and the north subtropical high pressure belts,a ribbon arid。
文摘Previous studies have shown evidence of atmospheric extratropical wave trains modulating sea ice area in the Weddell and Amundsen/Bellingshausen seas on intraseasonal time-scales(20–100 d). Here we investigate mechanisms relating intraseasonal extreme sea ice extent and Ekman layer dynamics with emphasis on the Weddell Sea. This study extends from 1989 to 2013 and focuses on the winter season. Wind stress τ is calculated with winds from the Climate Forecast System reanalysis(CFSR) to evaluate momentum transfer between the atmosphere and the Ekman layer. Lag-composites of the anomalies of Ekman transport and the Ekman pumping indicate that divergence of mass in the Ekman layer and upwelling lead the occurrence of extreme sea ice contraction on intraseasonal time-scales in the Weddell Sea. Opposite conditions(i.e., convergence of the mass and downwelling) lead extreme sea ice expansion on intraseasonal time-scales. This study suggests that the Ekman pumping resulting from the anomalous wind stress on intraseasonal time-scales can transport these warmer waters to the surface contributing to sea ice melting. Additionally, high resolution sea ice fraction and ocean currents obtained from satellite and in situ data are used to investigate in detail mechanisms associated with persistent extreme sea ice expansion and contraction on intraseasonal time-scales. These case studies reveal that atmospheric circumpolar waves on intraseasonal time-scales can induce contrasting anomalies of about ±20% in sea ice concentration at the Weddell and western Antarctica Peninsula margins within less than 30 d. This study shows that extreme anomalies in sea ice may lag between 5–25 d(1–5 pentads) the ocean-atmospheric forcing on intraseasonal time-scales.
文摘The mathematical model of peripheral twist extent(PTE) length was set up by studying the kinematics anddynamics of the yarn in rotor groove. The value of PTElength was calculated by using numerical method, andthe factors affecting the PTE length were also discussed.The results show that the theoretical predicted value ofPTE length seems to be consistent with the measured val-ue. The yarn linear density and rotor speed have re-markable effects on PTE length. The parameters includ-
文摘<strong>Background: </strong>Given the increase in the numbers of expatriates in Saudi Arabia and the shortage of information about expatriates’ oral health and periodontal disease severity and progression. <strong>Objectives: </strong>This study aimed to evaluate the effects of the racial differences on oral health and periodontal disease extent, staging, and grading among the multi-ethnic expatriates in the Aseer region, Saudi Arabia. <strong>Materials and Methods:</strong> This cross-sectional study was carried out on 300 expatriates in Aseer region, Saudi Arabia. They were divided into three equal racial different groups (n = 100), Arabs (AR), Asians (AS), and Africans (AF). The interviews of all participants were completed then the clinical examinations of periodontal diseases extent, staging, and grading parameters were performed. Statistical analysis was done by ANOVA test, Tukey’s test, and Chi-square test. The statistical significance level was determined at p < 0.05. <strong>Results: </strong>There were statistically significant differences in the comparison between the three ethnic/racial groups in clinical parameters except in GBI, PCR, FI, TFO, and BC, where there were no statistically significant differences in the comparison between the three ethnic/racial groups. There were differences associated with age, gender, smoking, and diabetes, without statistically significant differences among the three racial groups.<strong> Conclusion:</strong> We concluded that most participants in this study had a generalized severe grade 4 plaque-induced gingivitis and localized periodontitis stage III grade B.
文摘Recently the explored reserves submitted in the oil field mainly situate at the end of deposit in delta front area. During the exploitation and production, problems mainly show on lithologic deposit, for example, reserves are low and difficulty of producing is huge. Based on results of sand body dissection of dense well network of developed oil deposit, and combined with explored reserves, this article researches a relation between extent of well control and reserves precision of explored reserves of lithologic deposit in delta front area by well diluted method. This article has significant influence on objectively understanding our unexploited
文摘Education is to learn or to gain knowledge of something through being taught by others or through self-learning. The two most important words about education are teaching and learning. By definition, teachers are leaders, and to put it simply leaders lead. Teachers lead their students along the path of knowledge. As for students, they who can be equipped with academic knowledge and a set of practical skills can be useful members of society and make a contribution to the economic development of a nation and even the world. In this sense, we should keep in mind that to consistently improve the quality of education is to promise a bright future for the nation.
基金The National Key Research and Development Program of China under contract Nos 2016YFC1402704 and 2016YFC1401007the Open Research Fund of Key Laboratory of Digital Earth Science,Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences under contract No.2014LDE009+2 种基金the International Science and Technology Cooperation Project of China under contract No.2011DFA22260the National Natural Science Foundation of China under contract Nos U1606405 and41276181the Chinese Polar Environment Comprehensive Investigation&Assessment Program by the State Oceanic Administration under contract Nos 2015-02-04 and 2015-04-03-02
文摘A sea ice extent retrieval algorithm over the polar area based on scatterometer data of HY-2A satellite has been established.Four parameters are used for distinguishing between sea ice and ocean with Fisher's linear discriminant analysis method.The method is used to generate polar sea ice extent maps of the Arctic and Antarctic regions of the full 2013–2014 from the scatterometer aboard HY-2A(HY-2A-SCAT) backscatter data.The time series of the ice mapped imagery shows ice edge evolution and indicates a similar seasonal change trend with total ice area from DMSP-F17 Special Sensor Microwave Imager/Sounder(SSMIS) sea ice concentration data.For both hemispheres,the HY-2A-SCAT extent correlates very well with SSMIS 15% extent for the whole year period.Compared with Synthetic Aperture Radar(SAR) imagery,the HY-2A-SCAT ice extent shows good correlation with the Sentinel-1 SAR ice edge.Over some ice edge area,the difference is very evident because sea ice edges can be very dynamic and move several kilometers in a single day.
基金The Project of Comprehensive Evaluation of Polar Areas on Global and Regional Climate Changes under contract No.CHINARE2015-04-04the National Natural Science Foundation of China under contract No.41406027
文摘Satellite records show the minimum Arctic sea ice extents(SIEs) were observed in the Septembers of 2007 and2012, but the spatial distributions of sea ice concentration reduction in these two years were quite different.Atmospheric circulation pattern and the upper-ocean state in summer were investigated to explain the difference.By employing the ice-temperature and ice-specific humidity(SH) positive feedbacks in the Arctic Ocean, this paper shows that in 2007 and 2012 the higher surface air temperature(SAT) and sea level pressure(SLP)accompanied by more surface SH and higher sea surface temperature(SST), as a consequence, the strengthened poleward wind was favorable for melting summer Arctic sea ice in different regions in these two years. SAT was the dominant factor influencing the distribution of Arctic sea ice melting. The correlation coefficient is –0.84 between SAT anomalies in summer and the Arctic SIE anomalies in autumn. The increase SAT in different regions in the summers of 2007 and 2012 corresponded to a quicker melting of sea ice in the Arctic. The SLP and related wind were promoting factors connected with SAT. Strengthening poleward winds brought warm moist air to the Arctic and accelerated the melting of sea ice in different regions in the summers of 2007 and 2012. Associated with the rising air temperature, the higher surface SH and SST also played a positive role in reducing summer Arctic sea ice in different regions in these two years, which form two positive feedbacks mechanism.
文摘The spatial database management system of China geological survey extent is a social service system. Its aim is to help the government and the whole social public to expediently use the spatial database, such as querying, indexing, mapping and product outputting. The management system has been developed based on MAPGIS6.x SDK and Visual C++, considering the spatial database contents and structure and the requirements of users. This paper introduces the software structure, the data flow chart and some key techniques of software development.
基金Under the auspices of Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues of Chinese Academy of Sciences(No.XDA05050503)National Key Technology Research and Development Program of China(No.2013BAD11B00)National Natural Science Foundation of China(No.41301242)
文摘Studying the relationship between climate factors and soil organic carbon(SOC) is vitally important. However, how SOC responses to climate(temperature and precipitation) at cohesive extents is poorly studied. Two transects of approximately the same length(transect P and transect T) were selected to examine the variation of SOC content in relation to mean annual temperature(MAT) and mean annual precipitation(MAP). The coefficients of partial correlation between SOC density and MAT(Rt) and MAP(Rp) were determined to quantify the relationships between SOC density and the two climate factors. The results indicated that for transect T, Rt was statistically significant once the extent level was greater than or equal to two fundamental extent units, while for transect P, Rp showed statistical significance only at extent levels which were greater than two fundamental extent units. At the same extent levels but in different transects, Rts exhibited no zonal difference, but Rps did once the extent level was greater than two fundamental extent units. Therefore, to study the relationship between SOC density and different climate factors, different minimum extent levels should be examined. The results of this paper could deepen the understanding of the impacts that SOC pool has on terrestrial ecosystem and global carbon cycling.
基金supported by the National Natural Science Foundation of China (41530424)
文摘The interannual variability of the boreal winter Hadley circulation extents during the period of 1979e2014 and its links to El Ni^no-Southern Oscillation(ENSO) were investigated by using reanalysis datasets. Results showed that the El Ni^no(La Ni^na) events can induce the shrinking(expansion) of Hadley circulation extent in the Southern Hemisphere. For the Northern Hemisphere, El Ni^no(La Ni^na) mainly leads to shrinking(expansion) of the Hadley circulation extent in the middle and lower troposphere and expansion(shrinking) of the Hadley circulation extent in the upper troposphere. The ENSO associated meridional temperature gradients have close relationship with the Hadley circulation extents in both Hemispheres. But in the Northern Hemisphere, the ENSO associated eddy momentum flux divergence plays more important role in affecting the Hadley circulation extent than the meridional temperature gradient because of the small local Rossby number. In the Southern Hemisphere, as the ENSO induced eddy momentum flux divergence is small, the meridional temperature gradient dominates the change of the Hadley circulation extent.
