The degeneration of Bashang inland lake wetland in Hebei Province is caused by both some natural reasons,such as temperature rises and violent pathogenic wind,and some human factors like the large increase of populati...The degeneration of Bashang inland lake wetland in Hebei Province is caused by both some natural reasons,such as temperature rises and violent pathogenic wind,and some human factors like the large increase of population and arable area,the production of season-staggered vegetable,which have increased the water utilization and made many lakes dry up completely or partly.Based on the degeneration reasons,the related measures for restoring the function of Bashang wetland ecosystem were proposed in this paper.展开更多
An ecological regionalization index system was established for Bashang inland lake wetland based on ecological and environmental factors,with landform,geomorphy,vegetation types and climate as primary indices,micro-la...An ecological regionalization index system was established for Bashang inland lake wetland based on ecological and environmental factors,with landform,geomorphy,vegetation types and climate as primary indices,micro-landform,vegetation type,soil type,climate,ecosystem types,wetland features and human activities as secondary indices. Based on these index systems,the area was divided into three eco-environment regions and nine sub eco-environment regions. An eco-regional map of Bashang inland lake wetland was drawn by using GIS. The ecological characteristics,existing problems and control measures of each region were described. This study will supply guidance for the construction of local ecological environment and regulation of industrial structure,promoting sustainable development of Bashang inland lake wetland.展开更多
[Objective] This study aimed to investigate the pollen morphology of nine major crops in Bashang Plateau of Hebei Province. [Method] By using an optical microscope, pollen morphology of nine major crops in Bashang Pla...[Objective] This study aimed to investigate the pollen morphology of nine major crops in Bashang Plateau of Hebei Province. [Method] By using an optical microscope, pollen morphology of nine major crops in Bashang Plateau of Hebei Province was observed and compared. [Result] Pollen grains were spherical, nearly spherical or prolate; pollen grains of Cucurbita pepo were the largest, and those of Brassica campestris were the smallest; P/E value of Vicia faba was the maximum of 1.77, and that of Avena chinsis was the minimum of 1.00; there were six types of germinal apertures, including single-aperture, scattered-aperture, 3-aperture, 3-groove, 3-colporate and 3-4-colporate; there were four types of exine ornamentation, including reticulate ornamentation, warty ornamentation, spinulose ornamentation and granular ornamentation. [Conclusion] This study not only provided standard maps and related information for the identification of crop pollens in different strata, but also provided modern palynological evidence for extracting information of synarthropic plants (cultivated crops mostly) in different strata, deducing the natural environment ancient human lived in, and understanding the relationship between human and environmental changes.展开更多
Natural conditions in Bashang area are characterized by zonal transitions which are liable to be impacted by natural disasters and intensified human activities. The extremely fragile eco-environment is also liable to ...Natural conditions in Bashang area are characterized by zonal transitions which are liable to be impacted by natural disasters and intensified human activities. The extremely fragile eco-environment is also liable to have desertification formed and developed. In the 18 years from 1978 to 1996, the desertified land area of Bashang within the scope of the map nearly doubled, a total increase of 2199.11 km2, averaging an increase of 122.17 km2 per year. Moreover, the seriously desertified area increases rapidly. Land desertification in Bashang is the combined result of natural factors and irrational human economic activities. Cultivated land expansion, population growth, and overgrazing aggrevate desertification development.展开更多
The Bashang area is a water source area and ecological barrier zone for Beijing and Tianjin. The area is located at 200 km from Beijing and Tianjin and is a typical agriculture pasture interlacing zone, in which th...The Bashang area is a water source area and ecological barrier zone for Beijing and Tianjin. The area is located at 200 km from Beijing and Tianjin and is a typical agriculture pasture interlacing zone, in which the eco environment is vulnerable and hence it is sensitive to environmental change. The area is relatively lagged in social and economic development, where the traditional cultivation mode is predominated in agriculture and animal husbandry, but the disturbance by human activity is relatively small. Therefore, in order to reveal the interrelation between eco environmental change in the area and environmental change in Beijing and Tianjin area, it is fairly necessary to study the effect of land use and land cover change on nutrients in soil in this area. According to the actual situation of changed land use for the limited time period, five series of changed land plots were selected and 4 samples were collected from each series for the study. The samples were collected from different soil forming levels at the same site in different time. Analysis of the collected samples indicates that in the process of change of land use and land cover, the nutrients in soil, such as organic matter, total N, total P, total K, and available N, P, K, and B, Mo, Mn, Zn, Cu, and Fe, have regularly changed. When the land had changed from grassland and non irrigated farmland into woodland, and from non irrigated farmland into irrigated field, the nutrients in soil totally increased. But there exists some exception, i.e. quick acting N, P, K, and some microelements have appeared to be inconsistent with the mentioned above regularity in some cases.展开更多
Brooding is a major breeding investment of parental birds during the early nestling stage, and has important effects on the development and survival of nestlings. Investigating brooding behavior can help to understand...Brooding is a major breeding investment of parental birds during the early nestling stage, and has important effects on the development and survival of nestlings. Investigating brooding behavior can help to understand avian breeding investment strategies. From January to June in 2013 and 2014, we studied the brooding behaviors of long-tailed tits (Aegithalos caudatus glaucogularis) in Dongzhai National Nature Reserve, Henan Province, China. We analyzed the relationships between parental diurnal brooding duration and nestling age, brood size, temperature, relative breeding season, time of day and nestling frequencies during brooding duration. Results showed that female and male long-tailed tit parents had different breeding investment strategies during the early nestling stage. Female parents bore most of the brooding investment, while male parents performed most of the nestling feedings. In addition, helpers were not found to brood nestlings at the two cooperative breeding nests. Parental brooding duration was significantly associated with the food delivered to nestlings (F=86.10, dr=l, 193.94, P〈0.001), and was longer when the nestlings received more food. We found that parental brooding duration declined significantly as nestlings aged (F=5.99, dr=-1, 50.13, P=0.018). When nestlings were six days old, daytime parental brooding almost ceased, implying that long- tailed tit nestlings might be able to maintain their own body temperature by this age. In addition, brooding duration was affected by both brood size (F=12.74, dr=-1,32.08, P=0.001) and temperature (F=5.83, df=-l, 39.59, P=-0.021), with it being shorter in larger broods and when ambient temperature was higher.展开更多
Jinfengopteryx is a newly uncovered Archaeopteryx-like avialan bird outside Germany, which was found from the Jehol Biota of northern Hebei in northeastern China. It shares many characters only with Archaeopteryx by t...Jinfengopteryx is a newly uncovered Archaeopteryx-like avialan bird outside Germany, which was found from the Jehol Biota of northern Hebei in northeastern China. It shares many characters only with Archaeopteryx by the possession of three fenestrae in the antorbital cavity, 23 caudal vertebrae and long tail feathers attached to all the caudal vertebrae. But the former differs from the latter in the relatively short and high preorbital region of skull, more and closely packed teeth, much shorter forelimb compared to hindlimb. Such differences indicate Jinfengopteryx is even slightly more primitive than Archaeopteryx, although both birds can be placed at the root position of the avialan tree based on cladistic analysis. Shenzhouraptor is suggested to be slightly more advanced than Jinfengopteryx + Archaeopteryx, supported by some derived features in teeth, shoulder girdles and forelimbs such as the reduction of tooth number, dorsolaterally directed glenoid facet, very long forelimb and comparatively short manus. Meanwhile, the tail of Shenzhouraptor shows more primitive characters than those of Jinfengopteryx and Archaeopteryx, e.g., the strikingly longer tail composed of more caudal vertebrae and the long tail feathers attached only to distal caudal segments. The mixed primitive and advanced characters reveal the evident mosaic evolution among long-tailed avialan birds.展开更多
The Bashang region is a typical vulnerable eco-environmental zone. Our analysis of paleodunes, paleosol profiles, and lake changes taking place during last ten thousands years indicated that: (1) 10 - 6.9 ka B. P. was...The Bashang region is a typical vulnerable eco-environmental zone. Our analysis of paleodunes, paleosol profiles, and lake changes taking place during last ten thousands years indicated that: (1) 10 - 6.9 ka B. P. was a post-glacial temperature-increasing stage, in which lakes had their high water level; (2) 6.9 - 3.0 ka B. P. was a large warm stage, during which four paleosol layers were developed and climate fluctuation has assumed 4 - 5 small cold-humid and cold-dry alternations. Since 5.4 ka B. P, the lakes tended to gradually shrink; and by 2.1 ka B. P., water level has fallen by 2.7 m; (3) since 3.0 ka B. P. a general trend of the region was to change into a dry, warm-dry and cold-dry environment.展开更多
The repeated effects of vulnerable habitat and unreasonable human activities on the Bashang Plateau of China led the chestnut soil to degrade. It expresses in reducing soil CEC, decreasing nutrient content, decomposi...The repeated effects of vulnerable habitat and unreasonable human activities on the Bashang Plateau of China led the chestnut soil to degrade. It expresses in reducing soil CEC, decreasing nutrient content, decomposing organic complexes, and reducing humus in loose, steady and tight bond forms, respectively. The percentage of three forms are 21%—34%, 44%—55% and 5%—6.2%, respectively.展开更多
Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 198...Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 1984 to 2015 were selected to monitor the area of lakes in the Bashang Plateau and to analyze the spatiotemporal evolution and driving forces of lakes in the Bashang Plateau. The results showed that there were 47 lakes in the Bashang Plateau in 2015, with a total area of 37.63 km2, mainly distributed in the central and western regions of the region. From 1984 to 2015, the lakes in Bashang Plateau showed a shrinking trend. At the same time, there are obvious stage differences in lake changes. During 1984-1996, the number of lakes increased by 99 and the total area increased by 124.43 km2. From 1996 to 2015, the number of lakes decreased by 142, and the total area decreased by 183.96 km2. Before 1996, climate change was the dominant factor. However, the shrinkage of lakes after 1996 is the result of climate change and human activities. Among them, the large-scale planting of water consuming crops such as vegetables is the main human activity mode leading to lake shrinkage. This study will help to understand the expansion and contraction factors of the Bashang Plateau lakes in Hebei province and provide a reference for the future protection and management of the lakes.展开更多
Leveraging deep learning-based techniques to classify diseases has attracted extensive research interest in recent years.Nevertheless,most of the current studies only consider single-modal medical images,and the numbe...Leveraging deep learning-based techniques to classify diseases has attracted extensive research interest in recent years.Nevertheless,most of the current studies only consider single-modal medical images,and the number of ophthalmic diseases that can be classified is relatively small.Moreover,imbalanced data distribution of different ophthalmic diseases is not taken into consideration,which limits the application of deep learning techniques in realistic clinical scenes.In this paper,we propose a Multimodal Multi-disease Long-tailed Classification Network(M^(2)LC-Net)in response to the challenges mentioned above.M^(2)LC-Net leverages ResNet18-CBAM to extract features from fundus images and Optical Coherence Tomography(OCT)images,respectively,and conduct feature fusion to classify 11 common ophthalmic diseases.Moreover,Class Activation Mapping(CAM)is employed to visualize each mode to improve interpretability of M^(2)LC-Net.We conduct comprehensive experiments on realistic dataset collected from a Grade III Level A ophthalmology hospital in China,including 34,396 images of 11 disease labels.Experimental results demonstrate effectiveness of our proposed model M^(2)LC-Net.Compared with the stateof-the-art,various performance metrics have been improved significantly.Specifically,Cohen’s kappa coefficient κ has been improved by 3.21%,which is a remarkable improvement.展开更多
Objective To explore the semi-supervised learning(SSL) algorithm for long-tail endoscopic image classification with limited annotations.Method We explored semi-supervised long-tail endoscopic image classification in H...Objective To explore the semi-supervised learning(SSL) algorithm for long-tail endoscopic image classification with limited annotations.Method We explored semi-supervised long-tail endoscopic image classification in HyperKvasir,the largest gastrointestinal public dataset with 23 diverse classes.Semi-supervised learning algorithm FixMatch was applied based on consistency regularization and pseudo-labeling.After splitting the training dataset and the test dataset at a ratio of 4:1,we sampled 20%,50%,and 100% labeled training data to test the classification with limited annotations.Results The classification performance was evaluated by micro-average and macro-average evaluation metrics,with the Mathews correlation coefficient(MCC) as the overall evaluation.SSL algorithm improved the classification performance,with MCC increasing from 0.8761 to 0.8850,from 0.8983 to 0.8994,and from 0.9075 to 0.9095 with 20%,50%,and 100% ratio of labeled training data,respectively.With a 20% ratio of labeled training data,SSL improved both the micro-average and macro-average classification performance;while for the ratio of 50% and 100%,SSL improved the micro-average performance but hurt macro-average performance.Through analyzing the confusion matrix and labeling bias in each class,we found that the pseudo-based SSL algorithm exacerbated the classifier’ s preference for the head class,resulting in improved performance in the head class and degenerated performance in the tail class.Conclusion SSL can improve the classification performance for semi-supervised long-tail endoscopic image classification,especially when the labeled data is extremely limited,which may benefit the building of assisted diagnosis systems for low-volume hospitals.However,the pseudo-labeling strategy may amplify the effect of class imbalance,which hurts the classification performance for the tail class.展开更多
The study examines a water exploration and poverty alleviation project in Guyuan county.The study analyzes correlations between aquifers and multiple induced polarization(IP)parameters,including resistivity,polarizabi...The study examines a water exploration and poverty alleviation project in Guyuan county.The study analyzes correlations between aquifers and multiple induced polarization(IP)parameters,including resistivity,polarizability,deviation,half decay time,water-bearing factors,and Kc,a new parameter refined in this study.Based on the study,the well was placed accurately,and its maximum water inflow reached 30 m3/h.Kc value highlights the rate of change at early stages of IP secondary field.Kc value served as a quick indicator in this groundwater prospecting and is validated in practice.Progress has been made in finding new parameters in exploring water with IP method.Thanks to the project,local people have access to water and poverty alleviation has scored some achievements.展开更多
It is very suitable for planting quinoa in Bashang area of Hebei Province,but the local varieties of quinoa are disordered,which affects the development of quinoa industry.In this experiment,five quinoa varieties were...It is very suitable for planting quinoa in Bashang area of Hebei Province,but the local varieties of quinoa are disordered,which affects the development of quinoa industry.In this experiment,five quinoa varieties were selected and planted in Guyuan County.After two years of experiment,scientific conclusions were drawn on the yield,agronomic characters,economic characters,stress resistance and regional adaptability of these five varieties,and objective evaluation of variety characteristics and production and utilization value was conducted,which can provide scientific basis for variety identification,variety distribution and application of quinoa,and provide feedback information for promoting the development of quinoa industry.展开更多
[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three differe...[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three different types of returning farmland to forest(Hippophae rhamnoides Linn.forest,Caragana korshinskii forest and Ulmus pumila L.forest)were analyzed by taking the enclosed grassland as comparison in Bashang area of northern Hebei Province.[Result]The results showed that there were significant differences among different types.Order of the bulk density of soil:H.rhamnoides Linn.forest(1.17 g/cm^3)<U.pumila L.forest(1.24 g/cm^3)<C.korshinskii forest(1.26 g/cm^3)<enclosed grassland(1.61 g/cm^3);order of the total porosity of soil:H.rhamnoides Linn.forest(55.29%)>U.pumila L.forest(52.55%)>C.korshinskii forest(51.93%)<enclosed grassland(38.85%);order of the organic matter content of soil:H.rhamnoides Linn.forest(3.191%)>C.korshinskii forest(3.128%)>U.pumila L.forest(2.804%)>enclosed grassland(2.536%).[Conclusion]After returning farmland to forest,vegetation played a positive role in physicochemical properties of soil.There were significant differences in physicochemical properties of soil among different modes of returning farmland to forest,and the improvement effect of H.rhamnoides Linn.forest on physicochemical properties of soil was the best.展开更多
With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Alth...With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Although they can significantly promote the classifier learning of deep networks, they will unexpectedly impair the representative ability of the learned deep features to a certain extent. Therefore, this paper proposes a dual-channel learning algorithm with involution neural networks (DC-Invo) to take care of representation learning and classifier learning concurrently. In this work, the most important thing is to combine ResNet and involution to obtain higher classification accuracy because of involution’s wider coverage in the spatial dimension. The paper conducted extensive experiments on several benchmark vision tasks including Cifar-LT, Imagenet-LT, and Places-LT, showing that DC-Invo is able to achieve significant performance gained on long-tailed datasets.展开更多
基金Supported by Foundation Project of Hebei Province(D2009000299)~~
文摘The degeneration of Bashang inland lake wetland in Hebei Province is caused by both some natural reasons,such as temperature rises and violent pathogenic wind,and some human factors like the large increase of population and arable area,the production of season-staggered vegetable,which have increased the water utilization and made many lakes dry up completely or partly.Based on the degeneration reasons,the related measures for restoring the function of Bashang wetland ecosystem were proposed in this paper.
基金Supported by Science and Technology Research and Development Plan Project of Hebei Province (07276706D)Science and Technology Plan Project of Hebei Academy of Science (10104)~~
文摘An ecological regionalization index system was established for Bashang inland lake wetland based on ecological and environmental factors,with landform,geomorphy,vegetation types and climate as primary indices,micro-landform,vegetation type,soil type,climate,ecosystem types,wetland features and human activities as secondary indices. Based on these index systems,the area was divided into three eco-environment regions and nine sub eco-environment regions. An eco-regional map of Bashang inland lake wetland was drawn by using GIS. The ecological characteristics,existing problems and control measures of each region were described. This study will supply guidance for the construction of local ecological environment and regulation of industrial structure,promoting sustainable development of Bashang inland lake wetland.
基金Supported by Natural Science Foundation of Hebei Province (D2012302007)Science and Technology Project of Hebei Academy of Sciences (2013055507)+1 种基金Personnel Training Project of Hebei Province (2012)Talent Project of Hebei Academy of Sciences (2013045333-4)~~
文摘[Objective] This study aimed to investigate the pollen morphology of nine major crops in Bashang Plateau of Hebei Province. [Method] By using an optical microscope, pollen morphology of nine major crops in Bashang Plateau of Hebei Province was observed and compared. [Result] Pollen grains were spherical, nearly spherical or prolate; pollen grains of Cucurbita pepo were the largest, and those of Brassica campestris were the smallest; P/E value of Vicia faba was the maximum of 1.77, and that of Avena chinsis was the minimum of 1.00; there were six types of germinal apertures, including single-aperture, scattered-aperture, 3-aperture, 3-groove, 3-colporate and 3-4-colporate; there were four types of exine ornamentation, including reticulate ornamentation, warty ornamentation, spinulose ornamentation and granular ornamentation. [Conclusion] This study not only provided standard maps and related information for the identification of crop pollens in different strata, but also provided modern palynological evidence for extracting information of synarthropic plants (cultivated crops mostly) in different strata, deducing the natural environment ancient human lived in, and understanding the relationship between human and environmental changes.
基金National Natural Science Foundation of China No. 49894170
文摘Natural conditions in Bashang area are characterized by zonal transitions which are liable to be impacted by natural disasters and intensified human activities. The extremely fragile eco-environment is also liable to have desertification formed and developed. In the 18 years from 1978 to 1996, the desertified land area of Bashang within the scope of the map nearly doubled, a total increase of 2199.11 km2, averaging an increase of 122.17 km2 per year. Moreover, the seriously desertified area increases rapidly. Land desertification in Bashang is the combined result of natural factors and irrational human economic activities. Cultivated land expansion, population growth, and overgrazing aggrevate desertification development.
文摘The Bashang area is a water source area and ecological barrier zone for Beijing and Tianjin. The area is located at 200 km from Beijing and Tianjin and is a typical agriculture pasture interlacing zone, in which the eco environment is vulnerable and hence it is sensitive to environmental change. The area is relatively lagged in social and economic development, where the traditional cultivation mode is predominated in agriculture and animal husbandry, but the disturbance by human activity is relatively small. Therefore, in order to reveal the interrelation between eco environmental change in the area and environmental change in Beijing and Tianjin area, it is fairly necessary to study the effect of land use and land cover change on nutrients in soil in this area. According to the actual situation of changed land use for the limited time period, five series of changed land plots were selected and 4 samples were collected from each series for the study. The samples were collected from different soil forming levels at the same site in different time. Analysis of the collected samples indicates that in the process of change of land use and land cover, the nutrients in soil, such as organic matter, total N, total P, total K, and available N, P, K, and B, Mo, Mn, Zn, Cu, and Fe, have regularly changed. When the land had changed from grassland and non irrigated farmland into woodland, and from non irrigated farmland into irrigated field, the nutrients in soil totally increased. But there exists some exception, i.e. quick acting N, P, K, and some microelements have appeared to be inconsistent with the mentioned above regularity in some cases.
基金Foundation item: This study was supported by the National Natural Science Foundation of China (31472011)ACKNOWLEDGEMENTS We are grateful to Peng ZHANG, Zheng CHEN, Jia-Hui WANG, and Hui-Jia YUAN of Beijing Normal University for field assistance, and staff from Henan Dongzhai National Nature Reserve for help during field work. We also thank editor for revising the English, and the two reviewers for their constructive comments, which have helped to improve the manuscript.
文摘Brooding is a major breeding investment of parental birds during the early nestling stage, and has important effects on the development and survival of nestlings. Investigating brooding behavior can help to understand avian breeding investment strategies. From January to June in 2013 and 2014, we studied the brooding behaviors of long-tailed tits (Aegithalos caudatus glaucogularis) in Dongzhai National Nature Reserve, Henan Province, China. We analyzed the relationships between parental diurnal brooding duration and nestling age, brood size, temperature, relative breeding season, time of day and nestling frequencies during brooding duration. Results showed that female and male long-tailed tit parents had different breeding investment strategies during the early nestling stage. Female parents bore most of the brooding investment, while male parents performed most of the nestling feedings. In addition, helpers were not found to brood nestlings at the two cooperative breeding nests. Parental brooding duration was significantly associated with the food delivered to nestlings (F=86.10, dr=l, 193.94, P〈0.001), and was longer when the nestlings received more food. We found that parental brooding duration declined significantly as nestlings aged (F=5.99, dr=-1, 50.13, P=0.018). When nestlings were six days old, daytime parental brooding almost ceased, implying that long- tailed tit nestlings might be able to maintain their own body temperature by this age. In addition, brooding duration was affected by both brood size (F=12.74, dr=-1,32.08, P=0.001) and temperature (F=5.83, df=-l, 39.59, P=-0.021), with it being shorter in larger broods and when ambient temperature was higher.
基金financially supported by the National Basic Research Program of China(973 Project,Grant No.2006CB701405)the China Geological Survey,and the National Natural Science Foundation of China(Grant No.40272008).
文摘Jinfengopteryx is a newly uncovered Archaeopteryx-like avialan bird outside Germany, which was found from the Jehol Biota of northern Hebei in northeastern China. It shares many characters only with Archaeopteryx by the possession of three fenestrae in the antorbital cavity, 23 caudal vertebrae and long tail feathers attached to all the caudal vertebrae. But the former differs from the latter in the relatively short and high preorbital region of skull, more and closely packed teeth, much shorter forelimb compared to hindlimb. Such differences indicate Jinfengopteryx is even slightly more primitive than Archaeopteryx, although both birds can be placed at the root position of the avialan tree based on cladistic analysis. Shenzhouraptor is suggested to be slightly more advanced than Jinfengopteryx + Archaeopteryx, supported by some derived features in teeth, shoulder girdles and forelimbs such as the reduction of tooth number, dorsolaterally directed glenoid facet, very long forelimb and comparatively short manus. Meanwhile, the tail of Shenzhouraptor shows more primitive characters than those of Jinfengopteryx and Archaeopteryx, e.g., the strikingly longer tail composed of more caudal vertebrae and the long tail feathers attached only to distal caudal segments. The mixed primitive and advanced characters reveal the evident mosaic evolution among long-tailed avialan birds.
基金The National Natural Science Foundation of China(No.49872094andNo.40072097)
文摘The Bashang region is a typical vulnerable eco-environmental zone. Our analysis of paleodunes, paleosol profiles, and lake changes taking place during last ten thousands years indicated that: (1) 10 - 6.9 ka B. P. was a post-glacial temperature-increasing stage, in which lakes had their high water level; (2) 6.9 - 3.0 ka B. P. was a large warm stage, during which four paleosol layers were developed and climate fluctuation has assumed 4 - 5 small cold-humid and cold-dry alternations. Since 5.4 ka B. P, the lakes tended to gradually shrink; and by 2.1 ka B. P., water level has fallen by 2.7 m; (3) since 3.0 ka B. P. a general trend of the region was to change into a dry, warm-dry and cold-dry environment.
文摘The repeated effects of vulnerable habitat and unreasonable human activities on the Bashang Plateau of China led the chestnut soil to degrade. It expresses in reducing soil CEC, decreasing nutrient content, decomposing organic complexes, and reducing humus in loose, steady and tight bond forms, respectively. The percentage of three forms are 21%—34%, 44%—55% and 5%—6.2%, respectively.
文摘Lakes are important ecological water sources in the Bashang Plateau. Its expansion or shrinkage directly affects the ecological security of the plateau and its surrounding areas. In this study, Landsat images from 1984 to 2015 were selected to monitor the area of lakes in the Bashang Plateau and to analyze the spatiotemporal evolution and driving forces of lakes in the Bashang Plateau. The results showed that there were 47 lakes in the Bashang Plateau in 2015, with a total area of 37.63 km2, mainly distributed in the central and western regions of the region. From 1984 to 2015, the lakes in Bashang Plateau showed a shrinking trend. At the same time, there are obvious stage differences in lake changes. During 1984-1996, the number of lakes increased by 99 and the total area increased by 124.43 km2. From 1996 to 2015, the number of lakes decreased by 142, and the total area decreased by 183.96 km2. Before 1996, climate change was the dominant factor. However, the shrinkage of lakes after 1996 is the result of climate change and human activities. Among them, the large-scale planting of water consuming crops such as vegetables is the main human activity mode leading to lake shrinkage. This study will help to understand the expansion and contraction factors of the Bashang Plateau lakes in Hebei province and provide a reference for the future protection and management of the lakes.
基金the National Natural Science Foundation of China(No.62076035)。
文摘Leveraging deep learning-based techniques to classify diseases has attracted extensive research interest in recent years.Nevertheless,most of the current studies only consider single-modal medical images,and the number of ophthalmic diseases that can be classified is relatively small.Moreover,imbalanced data distribution of different ophthalmic diseases is not taken into consideration,which limits the application of deep learning techniques in realistic clinical scenes.In this paper,we propose a Multimodal Multi-disease Long-tailed Classification Network(M^(2)LC-Net)in response to the challenges mentioned above.M^(2)LC-Net leverages ResNet18-CBAM to extract features from fundus images and Optical Coherence Tomography(OCT)images,respectively,and conduct feature fusion to classify 11 common ophthalmic diseases.Moreover,Class Activation Mapping(CAM)is employed to visualize each mode to improve interpretability of M^(2)LC-Net.We conduct comprehensive experiments on realistic dataset collected from a Grade III Level A ophthalmology hospital in China,including 34,396 images of 11 disease labels.Experimental results demonstrate effectiveness of our proposed model M^(2)LC-Net.Compared with the stateof-the-art,various performance metrics have been improved significantly.Specifically,Cohen’s kappa coefficient κ has been improved by 3.21%,which is a remarkable improvement.
文摘Objective To explore the semi-supervised learning(SSL) algorithm for long-tail endoscopic image classification with limited annotations.Method We explored semi-supervised long-tail endoscopic image classification in HyperKvasir,the largest gastrointestinal public dataset with 23 diverse classes.Semi-supervised learning algorithm FixMatch was applied based on consistency regularization and pseudo-labeling.After splitting the training dataset and the test dataset at a ratio of 4:1,we sampled 20%,50%,and 100% labeled training data to test the classification with limited annotations.Results The classification performance was evaluated by micro-average and macro-average evaluation metrics,with the Mathews correlation coefficient(MCC) as the overall evaluation.SSL algorithm improved the classification performance,with MCC increasing from 0.8761 to 0.8850,from 0.8983 to 0.8994,and from 0.9075 to 0.9095 with 20%,50%,and 100% ratio of labeled training data,respectively.With a 20% ratio of labeled training data,SSL improved both the micro-average and macro-average classification performance;while for the ratio of 50% and 100%,SSL improved the micro-average performance but hurt macro-average performance.Through analyzing the confusion matrix and labeling bias in each class,we found that the pseudo-based SSL algorithm exacerbated the classifier’ s preference for the head class,resulting in improved performance in the head class and degenerated performance in the tail class.Conclusion SSL can improve the classification performance for semi-supervised long-tail endoscopic image classification,especially when the labeled data is extremely limited,which may benefit the building of assisted diagnosis systems for low-volume hospitals.However,the pseudo-labeling strategy may amplify the effect of class imbalance,which hurts the classification performance for the tail class.
基金This study was supported by 1:50000 Scale Regional Geological Survey of Mantouyying,Duikounao,Zhangbei County,Daxirang in Hebei Province(2200113).
文摘The study examines a water exploration and poverty alleviation project in Guyuan county.The study analyzes correlations between aquifers and multiple induced polarization(IP)parameters,including resistivity,polarizability,deviation,half decay time,water-bearing factors,and Kc,a new parameter refined in this study.Based on the study,the well was placed accurately,and its maximum water inflow reached 30 m3/h.Kc value highlights the rate of change at early stages of IP secondary field.Kc value served as a quick indicator in this groundwater prospecting and is validated in practice.Progress has been made in finding new parameters in exploring water with IP method.Thanks to the project,local people have access to water and poverty alleviation has scored some achievements.
基金Supported by Project of Hebei Provincial Department of Science and Technology(19227527D)。
文摘It is very suitable for planting quinoa in Bashang area of Hebei Province,but the local varieties of quinoa are disordered,which affects the development of quinoa industry.In this experiment,five quinoa varieties were selected and planted in Guyuan County.After two years of experiment,scientific conclusions were drawn on the yield,agronomic characters,economic characters,stress resistance and regional adaptability of these five varieties,and objective evaluation of variety characteristics and production and utilization value was conducted,which can provide scientific basis for variety identification,variety distribution and application of quinoa,and provide feedback information for promoting the development of quinoa industry.
基金Supported by Science and Technology Research Project of Colleges and Universities in Hebei Province(QN2015320)Natural Science Foundation of Hebei Province(C2015101020,E2019101012)Project of Chengde Finance Bureau(CZ2013011).
文摘[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three different types of returning farmland to forest(Hippophae rhamnoides Linn.forest,Caragana korshinskii forest and Ulmus pumila L.forest)were analyzed by taking the enclosed grassland as comparison in Bashang area of northern Hebei Province.[Result]The results showed that there were significant differences among different types.Order of the bulk density of soil:H.rhamnoides Linn.forest(1.17 g/cm^3)<U.pumila L.forest(1.24 g/cm^3)<C.korshinskii forest(1.26 g/cm^3)<enclosed grassland(1.61 g/cm^3);order of the total porosity of soil:H.rhamnoides Linn.forest(55.29%)>U.pumila L.forest(52.55%)>C.korshinskii forest(51.93%)<enclosed grassland(38.85%);order of the organic matter content of soil:H.rhamnoides Linn.forest(3.191%)>C.korshinskii forest(3.128%)>U.pumila L.forest(2.804%)>enclosed grassland(2.536%).[Conclusion]After returning farmland to forest,vegetation played a positive role in physicochemical properties of soil.There were significant differences in physicochemical properties of soil among different modes of returning farmland to forest,and the improvement effect of H.rhamnoides Linn.forest on physicochemical properties of soil was the best.
文摘With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Although they can significantly promote the classifier learning of deep networks, they will unexpectedly impair the representative ability of the learned deep features to a certain extent. Therefore, this paper proposes a dual-channel learning algorithm with involution neural networks (DC-Invo) to take care of representation learning and classifier learning concurrently. In this work, the most important thing is to combine ResNet and involution to obtain higher classification accuracy because of involution’s wider coverage in the spatial dimension. The paper conducted extensive experiments on several benchmark vision tasks including Cifar-LT, Imagenet-LT, and Places-LT, showing that DC-Invo is able to achieve significant performance gained on long-tailed datasets.