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Nitrogen addition promotes soil carbon accumulation globally

Science China Life Sciences 2025年第1期 284-293页

作者： xuemei yang Suhui Ma Erhan Huang Danhua Zhang Guoping Chen Jiangling Zhu Chengjun Ji Biao Zhu Lingli Liu Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China School of Ecology and Environmental ScienceYunnan University State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences

Soil is the largest carbon(C) reservoir in terrestrial ecosystems and plays a crucial role in regulating the global C cycle and climate *** nitrogen(N) deposition has been widely considered as a critical factor affecting soil organic carbon(SOC) storage, but its effect on SOC components with different stability remains unclear. Here, we analyzed extensive empirical data from 304 sites worldwide to investigate how SOC and its components respond to N addition. Our analysis showed that N addition led to a significant increase in bulk SOC(6.7%), with greater increases in croplands(10.6%) and forests(6.0%) compared to grasslands(2.1%). Regarding SOC components, N addition promoted the accumulation of plant-derived C(9.7%–28.5%) over microbial-derived C(0.2%), as well as labile(5.7%) over recalcitrant components(–1.2%), resulting in a shift towards increased accumulation of plant-derived labile C. Consistently, N addition led to a greater increase in particulate organic C(11.9%) than mineral-associated organic C(3.6%), suggesting that N addition promotes C accumulation across all pools, with more increase in unstable than stable pools. The responses of SOC and its components were best predicted by the N addition rate and net primary productivity. Overall, our findings suggest that N enrichment could promote the accumulation of plant-derived and non-mineral associated C and a subsequent decrease in the overall stability of soil C pool, which underscores the importance of considering the effects of N enrichment on SOC components for a better understanding of C dynamics in soils.

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Tungstophosphoric heteropolyacid supported onto neutral alumina: characterization and synthesis of acetals and ketals

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Rare Metals 2007年第2期26卷 152-157页

作者： GAO Jinzhang WEI Yunxia WANG xuemei yang Wu Chemistry ＆ Chemical Engineering College Northwest Normal University Lanzhou 730070 China

Tungstophosphoric acid （HPW） catalyst supported on the neural alumina was studied. It was prepared by means of an equilibrium and incipient wetness impregnation technique. Solution of HPW in 50% V/V ethanol-water was used to impregnate Al2O3 at 25℃. It was found that the catalyst containing 30% PW by calcination at 500℃ showed a higher catalytic activity in the synthesis of acetals and/or ketals. In the following condition, that is, the molar ratio of aldehyde/ketone to glycol being 1：1.5, the mass fraction of the catalyst used was 0.5%, and the reaction time was 1.0 h; the yields of ketals and acetals could reach up to 60.5%-86.7%. Moreover, it could be easily recovered and reused.

关键词： heteropolyacid tungstophosphodc catalyst catalytic activity acetal ketal.

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Assessment of desertification in Eritrea: land degradation based on Landsat images

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Journal of Arid Land 2019年第3期11卷 319-331页

作者： Mihretab G GHEBREZGABHER yang Taibao yang xuemei WANG Congqiang Institute of Glaciology and Eco-Geography College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China College of Business and Social Sciences Adi Keihi 59Eritrea Gansu Desert Control Research Institute Lanzhou 730070China

Remote sensing is an effective way in monitoring desertification dynamics in arid and semi-arid *** this study,we used a decision tree method based on NDVI(normalized difference vegetation index),SAVI(soil adjusted vegetation index),and vegetation cover proportion to quantify and analyze the desertification in Eritrea using Landsat data of the 1970 s,1980 s and *** results demonstrate that the NDVI value and the annual mean precipitation declined while the temperature increased over the past 40 *** desertified land increased from 4.82×10^4 km^2(38.5%)in the 1970 s to 8.38×10^4 km^2(66.9%)in 2014:approximately 85%of the land of the country was under serious desertification,which significantly occurred in arid and semi-arid lowlands of the country(eastern,northern,and western lowlands)with relatively scarce precipitation and high *** non-desertified area,mostly located in the sub-humid eastern escarpment,also declined from approximately 2.1%to 0.5%.The study concludes that the desertification is a cause of serious land degradation in Eritrea and may link to climate changes,such as low and unpredictable precipitation,and prolonged drought.

关键词： desertification Landsat images NDVI index SPI analysis Eritrea

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Integrating host biological and ecological variables to predict probability of haemosporidian infection in raptors

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Avian Research 2024年第2期15卷 255-264页

作者： Kai Gao xuemei yang Xi Huang Wenhong Deng Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijing100875China

Variations in host traits that influence their exposure and susceptibility may impact probability of vector-transmitted ***,identifying the predictors of infection probability is necessary to understand the risk of disease outbreaks during expanding environmental ***,we conducted a large survey based on microscopic examination and molecular analysis of haemosporidian parasite infection in raptors rescued at the Beijing Raptor Rescue *** these data with biological and ecological variables of the raptors,we determined predictors that affect the probability of haemosporidian infection using generalized linear mixed models and multimodel *** results showed that infection probability exhibited considerable variation across host species in raptors,and body mass,sex,and evolutionary history played relatively weaker roles in driving infection ***,activity pattern,age,geographic range size,migration distance,and nest type were important predictors of the probability of haemosporidian infection,and the role of each predictor differed in the three main haemosporidian genera(Plasmodium,Haemoproteus,and Leucocytozoon).This macro-ecological analysis will add to our understanding of host traits that influence the probability of avian haemosporidian infection and will help inform risk of emerging diseases.

关键词： Activity pattern Emerging infectious diseases Infection probability Interspecific variation Migratory exposure

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Research on Multi-Scale Feature Fusion Network Algorithm Based on Brain Tumor Medical Image Classification

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Computers, Materials & Continua 2024年第6期79卷 5313-5333页

作者： Yuting Zhou xuemei yang Junping Yin Shiqi Liu Graduate School China Academy of Engineering PhysicsBeijing100000China Department of Computational Mathematics Beijing Institute of Applied Physics and Computational MathematicsBeijing100000China National Key Laboratory of Computational Physics Beijing100088China Shanghai Zhangjiang Institute of Mathematics Shanghai201203China

Gliomas have the highest mortality rate of all brain *** classifying the glioma risk period can help doctors make reasonable treatment plans and improve patients’survival *** paper proposes a hierarchical multi-scale attention feature fusion medical image classification network(HMAC-Net),which effectively combines global features and local *** network framework consists of three parallel layers:The global feature extraction layer,the local feature extraction layer,and the multi-scale feature fusion layer.A linear sparse attention mechanism is designed in the global feature extraction layer to reduce information *** the local feature extraction layer,a bilateral local attention mechanism is introduced to improve the extraction of relevant information between adjacent *** the multi-scale feature fusion layer,a channel fusion block combining convolutional attention mechanism and residual inverse multi-layer perceptron is proposed to prevent gradient disappearance and network degradation and improve feature representation *** double-branch iterative multi-scale classification block is used to improve the classification *** the brain glioma risk grading dataset,the results of the ablation experiment and comparison experiment show that the proposed HMAC-Net has the best performance in both qualitative analysis of heat maps and quantitative analysis of evaluation *** the dataset of skin cancer classification,the generalization experiment results show that the proposed HMAC-Net has a good generalization effect.

关键词： Medical image classification feature fusion transformer

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Practicing the concept of “structuring” processing in the manufacture of polymer films

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Science China Chemistry 2023年第4期66卷 993-1010页

作者： Tong Wu Ke Wang Xiufeng Chen xuemei yang Ming Xiang Qiang Fu State Key Laboratory of Polymer Materials Engineering Sichuan UniversityChengdu 610065China Shenzhen Senior Technology Material Co. Ltd.Shenzhen 518127China

Polymer processing is a technology used to transfer raw materials into products with different shapes and functionalities and is a key step for polymer *** years of development,the polymer processing task has changed from traditional processing,which mainly addresses the specific shapes of articles and focuses on the effect of processing on the structures and properties of polymers,to modern processing,which directly transforms a“designed structure”into commercial products via *** is the so-called“structuring”*** to the unique long-chain nature and slow topological relaxation,polymers are always driven and frozen into different nonequilibrium conformations,providing an effective way to design a given polymer material with desired structure and tunable performances via *** the endless number of processing techniques,film casting is a prototypical pathway involving high supercooling or/and a strong flow field,based on which diverse thin polymer films have been successfully *** this review,taking isotactic polypropylene(i PP)film as an example,we highlight the strategy of“structuring”processing,in which we transform various crystalline structures of i PP into diverse commercial film products.

关键词： structuring processing film casting dimensional uniformity crystalline structure biaxially oriented film lithium-ion batteryseparator

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Low-complexity 2D coherently distributed sources decoupled DOAs estimation method

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Science in China(Series F) 2009年第5期52卷 835-842页

作者： GUO XianSheng WAN Qun yang WanLin LEI xuemei Department of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 China

The existing directions-of-arrival （DOAs） estimation methods for two-dimensional （2D） coherently distributed sources need one- or two-dimensional search, and the computational complexities of them are high. In addition, most of them are designed for special angular signal distribution functions. As a result, their performances will degenerate when deal with different sources with different angular signal distribution functions or unknown angular signal distribution functions. In this paper, a low-complexity decoupled DOAs estimation method without searching using two parallel uniform linear arrays （ULAs） is proposed for coherently distributed sources, as well as a novel parameter matching method. It can resolve the problems mentioned above efficiently. Simulation results validate the effectiveness of our approach.

关键词： 2D coherently distributed source uniform linear array direction-of-arrival (DOA) decoupled estimation quadric rotational invariance property (QRIP)

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民族地区生态旅游环境承载力评价研究

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南阳师范学院学报 2025年第1期24卷 9-17页

作者：杨雪梅摆利军秦宏毅兰州文理学院旅游学院甘肃兰州730000 兰州文理学院文旅产业高质量发展研究院文旅融合发展研究中心甘肃兰州730000

随着旅游业的快速发展,高强度的自然资源开发利用对民族地区社会、环境的影响受到广泛关注,而生态旅游环境承载力研究大多基于政策制定者或经营管理者角度展开,缺乏消费者视角的观察与反馈,导致评价结果出现向好偏差。此外,对民族地区... 详细信息

随着旅游业的快速发展,高强度的自然资源开发利用对民族地区社会、环境的影响受到广泛关注,而生态旅游环境承载力研究大多基于政策制定者或经营管理者角度展开,缺乏消费者视角的观察与反馈,导致评价结果出现向好偏差。此外,对民族地区地方性以及社会心理等因素考虑相对较少。以旅游资源富集但生态环境脆弱且经济相对落后的黄河上游甘南藏族自治州为例,构建生态旅游环境承载力评价指标,开展基于消费者观察视角的旅游环境承载力评价研究。结果显示:研究区综合旅游环境处于亚承载状态,具有较大的生态旅游开发空间。自然资源既是当地旅游业发展的竞争优势,也是最大的掣肘因素,迫切需要加大绿色转型发展、资金投入与高素质管理人才引进力度。此外,当地民族民俗文化旅游资源开发程度较低,旅游交通运输、餐饮、住宿接待能力以及基础设施条件需要提升。本研究是生态旅游环境承载力多视角信息挖掘、重组与评价的探索尝试,可为当地旅游资源优化配置与旅游业高质量发展提供借鉴。

关键词：生态旅游环境承载力游客感知甘南藏族自治州

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Cloning and Characterization of a New κ-Carrageenase Gene from Marine Bacterium Pseudoalteromonas sp. QY203

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Journal of Ocean University of China 2015年第6期14卷 1082-1086页

作者： XU Xiaoyan LI Shangyong yang xuemei YU Wengong HAN Feng Key Laboratory of Marine Drugs of Chinese Ministry of Education Provincial Key Laboratory of Glycoscience & Glycotechnology of Shandong School of Medicine and Pharmacy Ocean University of China Department of Stomatology The Affiliated Hospital of Qingdao University

kappa-carrageenan oligosaccharides exhibit various biological activities. Enzymatic degradation by kappa-carrageenase is safe and controllable. Therefore, kappa-carrageenases have captured more and more attentions. In this study, a kappa-carrageenase encoding gene, cgkX, was cloned from Pseudoalteromonas sp. QY203 with degenerate and inverse PCR. It comprised an ORF of 1194 bp in length, encoding a protein with 397 amino acid residues. CgkX is a new member of glycoside hydrolase family 16. The deduced amino acid sequence shared a high similarity with CgkX of Pseudoalteromonas kappa-carrageenase; however, the recombinant CgkX showed different biochemical characteristics. The recombinant enzyme was most active at pH 7.0 and 55A degrees C in the presence of 300 mmol L-1 NaCl. It was stable in a broad range of acidity ranging from pH 3.0 to pH 10.0 when temperature was below 40A degrees C. More than 80% of its activity was maintained after being incubated at pH 3.6-10.0 and 4A degrees C for 24 h. CgkX retained more than 90% of activity after being incubated at 40A degrees C for 1 h. EDTA and SDS (1 mmol L-1) did not inhibit its activity. CgkX hydrolyzed kappa-carrageenan into disaccharide and tetrasaccharide as an endo-cleaver. All these characteristics demonstrated that CgkX is applicable to both kappa-carrageenan oligosaccharide production and kappa-carrageenase structure-function research.

关键词： kappa-carrageenase cloning expression characterization Pseudoalteromonas

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Hyper-spectral characteristics of rolled-leaf desert vegetation in the Hexi Corridor, China

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Journal of Arid Land 2019年第3期11卷 332-344页

作者： WEI Huaidong yang xuemei ZHANG Bo DING Feng ZHANG Weixing LIU Shizeng CHEN Fang College of Geography and Environment Science Northwest Normal UniversityLanzhou 730070China State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating Gansu Desert Control Research InstituteLanzhou 730070China Key Laboratory of Remote Sensing of Gansu Province Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Desert plants survive harsh environment using a variety of drought-resistant structural modifications and physio-ecological ***-leaf plants roll up their leaves during periods of drought,making it difficult to distinguish between the external structures of various types of plants,it is therefore necessary to carry out spectral characteristics analysis for species identification of these rolled-leaf *** on hyper-spectral data measured in the field,we analyzed the spectral characteristics of seven types of typical temperate zone rolled-leaf desert plants in the Hexi Corridor,China using a variety of mathematical transformation *** results show that:(1)during the vigorous growth period in July and August,the locations of the red valleys,green peaks,and three-edge parameters,namely,the red edge,the blue edge,and the yellow edge of well-developed rolled-leaf desert plants are essentially consistent with those of the majority of terrestrial vegetation types;(2)the absorption regions of liquid water,i.e.,1400-1500 and 1600-1700 nm,are the optimal bands for distinguishing various types of rolled-leaf desert plants;(3)in the leaf reflectance regions of 700-1250 nm,which is controlled by cellular structure,it is difficult to select the characteristic bands for differentiation rolled-leaf desert vegetation;and(4)after processing the spectral reflectance curves using a first-order differential,the envelope removal method,and the normalized differential ratio,we identify the other characteristic bands and parameters that can be used for identifying various types of temperate zone rolled-leaf desert plants,i.e.,the 510-560,650-700 and 1330-1380 nm regions,and the red edge *** general,the mathematical transformation methods in the study are effective tools to capture useful spectral information for species identification of rolled-leaf plants in the Hexi Corridor.

关键词： rolled-leaf desert vegetation spectral characteristics mathematical transformation vegetation identification Hexi Corridor

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