检索结果-南通市图书馆

Understory seedlings of Quercus mongolica survive by phenological escape

Forest Ecosystems 2024年第2期11卷 236-246页

作者： Shixiong Wu Ying Liu Lulu He Wei Zeng Qijing Liu College of forestry Beijing Forestry UniversityBeijing100083China

Understanding understory seedling regeneration mechanisms is important for the sustainable development of temperate primary forests in the context of increasingly intense climate warming *** poor regeneration of dominant tree species,however,is one of the biggest challenges it faces at the ***,the regeneration of the shade-intolerant Quercus mongolica seedling is difficult in primary forests,which contrasts with the extreme abundance of understory seedlings in secondary *** mechanism behind the interesting phenomenon is still *** study used in-situ monitoring and nursery-controlled experiment to investigate the survival rate,growth performance,as well as nonstructural carbohydrate (NSC) concentrations and pools of various organ tissues of seedlings for two consecutive years,further analyze the understory light availability and simulate the foliage carbon (C) gain in the secondary and primary *** suggested that seedlings in the secondary forest had greater biomass allocation aboveground,height and specific leaf area (SLA) in summer,which allowed the seedling to survive longer in the canopy closure *** light availability and positive C gain in early spring and late autumn are key factors affecting the growth and survival of understory seedlings in the secondary forest,whereas seedlings in the primary forest had annual negative carbon *** the growing season,the total NSC concentrations of seedlings gradually decreased,whereas those of seedlings in the secondary forest increased significantly in autumn,and were mainly stored in roots for winter consumption and the following year's summer shade period,which was verified by the nursery-controlled experiment that simulated autumn enhanced light availability improved seedling survival rate and NSC *** conclusion,our results revealed the survival trade-off strategies of Quercus mongolica seedlings and highlighted the necessity of high light availability d

关键词： Carbon gain Nonstructural carbohydrate Recruitment Trade-off Biomass allocation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reconstructing historical forest fire risk in the non-satellite era using the improved forest fire danger index and long short-term memory deep learning-a case study in Sichuan Province,southwestern China

引用

Forest Ecosystems 2024年第1期11卷 87-99页

作者： Yuwen Peng Huiyi Su Min Sun Mingshi Li Co-Innovation Center for Sustainable forestry in Southern China Nanjing Forestry UniversityNanjing 210037China College of forestry Nanjing Forestry UniversityNanjing 210037China

Historical forest fire risk databases are vital for evaluating the effectiveness of past forest management approaches,enhancing forest fire warnings and emergency response capabilities,and accurately budgeting potential carbon emissions resulting from ***,due to the unavailability of spatial information technology,such databases are extremely difficult to build reliably and completely in the non-satellite *** study presented an improved forest fire risk reconstruction framework that integrates a deep learning-based time series prediction model and spatial interpolation to address the challenge in Sichuan Province,southwestern ***,the forest fire danger index(FFDI)was improved by supplementing slope and aspect *** compared the performances of three time series models,namely,the autoregressive integrated moving average(ARIMA),Prophet and long short-term memory(LSTM)in predicting the modified forest fire danger index(MFFDI).The bestperforming model was used to retrace the MFFDI of individual stations from 1941 to *** this,the Anusplin spatial interpolation method was used to map the distributions of the MFFDI at five-year intervals,which were then subjected to weighted overlay with the distance-to-river layer to generate forest fire risk maps for reconstructing the forest fire danger *** results revealed LSTM as the most accurate in fitting and predicting the historical MFFDI,with a fitting determination coefficient(R^2)of 0.709,mean square error(MSE)of0.047,and validation R^2 and MSE of 0.508 and 0.11,*** validation of the predicted forest fire risk maps indicated that 5 out of 7 historical forest fire events were located in forest fire-prone areas,which is higher than the results determined from the original FFDI(2 out of 7).This proves the effectiveness of the improved MFFDI and indicates a high level of reliability of the historical forest fire risk reconstruction method proposed in this stu

关键词： Forest fire risk reconstruction MFFDI Time series models LSTM ARIMA Prophet Anusplin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of drought on non-structural carbohydrates and C,N,and P stoichiometric characteristics of Pinus yunnanensis seedlings

引用

Journal of forestry Research 2024年第1期35卷 90-102页

作者： Zhijuan Zhao Lina Wang Yuanxi Liu Jianli Sun Jiandong Xiao Qiong Dong Lianfang Li Wanjie Zhang Chao Wang Junwen Wu College of forestry Southwest Forestry UniversityKunming 650224YunnanPeople’s Republic of China

To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant *** results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress *** utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe *** was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each *** in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that *** seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization ***,these results suggest that the physiological activities of all organs of *** seedlings are restricted under drought and that trade-offs exist between different physiological indicators and *** findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in *** seedlings.

关键词： Pinus yunnanensis seedlings Drought Non-structural carbohydrates C,N,P stoichiometric characteristics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Three-dimensional(3D)parametric measurements of individual gravels in the Gobi region using point cloud technique

引用

Journal of Arid Land 2024年第4期16卷 500-517页

作者： JING Xiangyu HUANG Weiyi KAN Jiangming College of Engineering Beijing Forestry UniversityBeijing 100083China Key Laboratory of State forestry Administration on forestry Equipment and Automation Beijing 100083China

Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed *** presence significantly influences the movement of sand and ***,the complex origins and diverse materials constituting the Gobi result in notable differences in saltation processes across various Gobi *** is challenging to describe these processes according to a uniform ***,it becomes imperative to articulate surface characteristics through parameters such as the three-dimensional(3D)size and shape of *** morphology information for Gobi gravels is essential for studying its genesis and sand *** enhance the efficiency and information yield of gravel parameter measurements,this study conducted field experiments in the Gobi region across Dunhuang City,Guazhou County,and Yumen City(administrated by Jiuquan City),Gansu Province,China in March 2023.A research framework and methodology for measuring 3D parameters of gravel using point cloud were developed,alongside improved calculation formulas for 3D parameters including gravel grain size,volume,flatness,roundness,sphericity,and equivalent grain *** multi-view geometry technology for 3D reconstruction allowed for establishing an optimal data acquisition scheme characterized by high point cloud reconstruction efficiency and clear ***,the proposed methodology incorporated point cloud clustering,segmentation,and filtering techniques to isolate individual gravel point *** point cloud algorithms,including the Oriented Bounding Box(OBB),point cloud slicing method,and point cloud triangulation,were then deployed to calculate the 3D parameters of individual *** systematic processes allow precise and detailed characterization of individual *** gravel grain size and volume,the correlation coefficients between point cloud and manual measurements all exceeded 0.9000,confirming the feasibility of the proposed methodol

关键词： Gobi gravels three-dimensional(3D)parameters point cloud 3D reconstruction Random Sample Consensus(RANSAC)algorithm Density-Based Spatial Clustering of Applications with Noise(DBSCAN)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spatio-temporal Evolution Characteristics and Driving Forces of Winter Urban Heat Island:A Case Study of Rapid Urbanization Area of Fuzhou City,China

引用

Chinese Geographical Science 2024年第1期34卷 135-148页

作者： WANG Zili LU Chunyan SU Yanlin SU Yue YU Qianru LI Wenzhe YANG Nuocheng College of Computer and Information Sciences Fujian Agriculture and Forestry UniversityFuzhou350002China Key Laboratory of Smart Agriculture and forestry(Fujian Agriculture and forestry University) Fujian Province UniversityFuzhou350002China College of forestry Fujian Agriculture and Forestry UniversityFuzhou350002China

Under the influence of anthropogenic and climate change,the problems caused by urban heat island(UHI)has become increasingly *** order to promote urban sustainable development and improve the quality of human settlements,it is significant for exploring the evolution characteristics of urban thermal environment and analyzing its driving *** the Landsat series images as the basic data sources,the winter land surface temperature(LST)of the rapid urbanization area of Fuzhou City in China was quantitatively retrieved from 2001 to *** comprehensively the standard deviation ellipse model,profile analysis and GeoDetector model,the spatio-temporal evolution characteristics and influencing factors of the winter urban thermal environment were systematically *** results showed that the winter LST presented an increasing trend in the study area during 2001–2021,and the winter LST of the central urban regions was significantly higher than the *** was a strong UHI effect from 2001 to 2021with an expansion trend from the central urban regions to the suburbs and coastal areas in space *** LST of green lands and wetlands are significantly lower than croplands,artificial surface and unvegetated *** and water bodies had a significant mitigation effect on UHI,especially in the *** winter UHI had been jointly driven by the underlying surface and socio-economic factors in a nonlinear or two-factor interactive enhancement mode,and socio-economic factors had played a leading *** research could provide data support and decision-making references for rationally planning urban layout and promoting sustainable urban development.

关键词： winter urban heat island(UHI) rapid urbanization area land surface temperature(LST)retrieval profile analysis GeoDetector model Fuzhou City,China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Design of multi-section luffing apple pruning equipment and cutting test of the key components

引用

International Journal of Agricultural and Biological Engineering 2024年第1期17卷 109-117页

作者： Siyuan Tong Wenbin Li Yaxiong Wang Lei Zhang Feng Kang School of Technology Beijing Forestry UniversityKey Lab of State Forestry and Grassland Administration for Forestry Equipment and AutomationBeijing 100083China

In order to reduce the labor intensity and improve the efficiency of pruning,this study designed a multi-section luffing apple pruning equipment suitable for apple orchards in hilly and mountainous areas of *** the essay,the structure and working principle of the equipment are expounded,the cutter was analyzed,and the parameters were *** the self-made test bench to simulate the field experiment,this study selected the ratio of cutting speed to feeding speed and feeding speed as the influencing factors and took the cut-off rate,cutting efficiency and cutting power as the objectives to carry out single factor experiment and quadratic regression orthogonal *** test results show that the cutting power increases with the increase of ratio of cutting speed to feeding speed,and the cut-off rate and cutting efficiency first increase and then *** the feeding speed increases,the cutting efficiency and power increase,and the cut-off rate *** the cutoff rate was greater than 80%,the optimal combination of operating parameters was the feeding speed of 0.55 m/s and ratio of cutting speed to feeding speed of *** this combination,the cut-off rate was 84.9%,the cutting efficiency was 13.1,and the cutting power was 175.7 *** error between the predicted target value of the model and the average measured target value was less than 7%,so the test results are *** to the obtained optimal operating parameters,the actual cutting experiment of the pruning equipment in the field was carried out,and the cutting rate was 96.3%,which meet the design *** study can also meet the needs of mechanized pruning of fruit trees with different crown shapes,improve the applicability of pruning equipment,and provide support for the development of mechanized pruning equipment in China.

关键词： apple pruning equipment cutting test optimal parameters regression analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Identification of Phenylalanine Ammonia-Lyase(PAL)Genes from Pinus yunnanensis and an Analysis of Enzyme Activity in vitro

引用

Phyton-International Journal of Experimental Botany 2024年第3期93卷 503-516页

作者： Dejin Mu Lin Chen Heze Wang Zhaoliu Hu Sihui Chen Shi Chen Nianhui Cai Yulan Xu Junrong Tang Key Laboratory of National forestry and Grassland Administration on Biodiversity Conservation in Southwest China Southwest Forestry UniversityKunming650224China College of forestry Southwest Forestry UniversityKunming650224China

Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus *** the present study,three PAL genes were cloned and identiﬁed from *** seedlings for theﬁrst time,namely,PyPAL-1,PyPAL-2,and *** results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 *** tree analysis revealed that PyPALs have high homology with other known PAL genes in other *** vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric *** PyPAL genes were expressed in different tissues in 1-year-old ***,and such genes had different expression *** study lays a foundation for further understanding of the biosynthesis of secondary metabolites in ***.

关键词： Pinus yunnanensis phenylalanine ammonia-lyase enzyme activity in vitro functional analysis secondary metabolites

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Predicting Users’ Latent Suicidal Risk in Social Media: An Ensemble Model Based on Social Network Relationships

引用

Computers, Materials & Continua 2024年第6期79卷 4259-4281页

作者： Xiuyang Meng Chunling Wang Jingran Yang Mairui Li Yue Zhang Luo Wang School of Information Science and Technology Beijing Forestry UniversityBeijing100083China Engineering Research Center for forestry-Oriented Intelligent Information Processing of National forestry and Grassland Administration Beijing100083China

Suicide has become a critical concern,necessitating the development of effective preventative *** media platforms offer a valuable resource for identifying signs of suicidal *** progress in detecting suicidal ideation on social media,accurately identifying individuals who express suicidal thoughts less openly or infrequently poses a significant *** tackle this,we have developed a dataset focused on Chinese suicide narratives from Weibo’s Tree Hole feature and introduced an ensemble model named Text Convolutional Neural Network based on Social Network relationships(TCNN-SN).This model enhances predictive performance by leveraging social network relationship features and applying correction factors within a weighted linear fusion *** is specifically designed to identify key individuals who can help uncover hidden suicidal users and *** model,assessed using the bespoke dataset and benchmarked against alternative classification approaches,demonstrates superior accuracy,F1-score and AUC metrics,achieving 88.57%,88.75%and 94.25%,respectively,outperforming traditional TextCNN models by 12.18%,10.84%and 10.85%.We assert that our methodology offers a significant advancement in the predictive identification of individuals at risk,thereby contributing to the prevention and reduction of suicide incidences.

关键词： Suicide risk prediction social media social network relationships Weibo Tree Hole deep learning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nonlinear Registration of Brain Magnetic Resonance Images with Cross Constraints of Intensity and Structure

引用

Computers, Materials & Continua 2024年第5期79卷 2295-2313页

作者： Han Zhou HongtaoXu Xinyue Chang Wei Zhang Heng Dong Digital Fujian Research Institute of Big Data forAgriculture and forestry Fujian Agriculture and Forestry UniversityFuzhou350002China College of Computer and Information Science Fujian Agriculture and Forestry UniversityFuzhou350002China

Many deep learning-based registration methods rely on a single-stream encoder-decoder network for computing deformation fields between 3D ***,these methods often lack constraint information and overlook semantic consistency,limiting their *** address these issues,we present a novel approach for medical image registration called theDual-VoxelMorph,featuring a dual-channel cross-constraint *** innovative network utilizes both intensity and segmentation images,which share identical semantic information and feature *** encoder-decoder structures calculate deformation fields for intensity and segmentation images,as generated by the dual-channel cross-constraint *** design facilitates bidirectional communication between grayscale and segmentation information,enabling the model to better learn the corresponding grayscale and segmentation details of the same anatomical *** ensure semantic and directional consistency,we introduce constraints and apply the cosine similarity function to enhance semantic *** on four public datasets demonstrates superior performance compared to the baselinemethod,achieving Dice scores of 79.9%,64.5%,69.9%,and 63.5%for OASIS-1,OASIS-3,LPBA40,and ADNI,respectively.

关键词： Medical image registration cross constraint semantic consistency directional consistency dual-channel

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Afforestation with an age-sequence of Mongolian pine plantation promotes soil microbial residue accumulation in the Horqin Sandy Land, China

引用

Journal of Arid Land 2024年第4期16卷 567-579页

作者： GUO Jingwen SONG Xueshu WANG Xiao DU Zhangliu LU Sen State Key Laboratory of Efficient Production of Forest Resources Research Institute of ForestryChinese Academy of ForestryBeijing 100091China Co-Innovation Center for Sustainable forestry in Southern China Nanjing Forestry UniversityNanjing 210037China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China

Land use change affects the balance of organic carbon(C)reserves and the global C *** residues are essential constituents of stable soil organic C(SOC).However,it remains unclear how microbial residue changes over time following *** this study,16-,23-,52-,and 62-year-old Mongolian pine stands and 16-year-old cropland were studied in the Horqin Sandy Land,*** analyzed changes in SOC,amino sugar content,and microbial parameters to assess how microbial communities influence soil C transformation and *** results showed that SOC storage increased with stand age in the early stage of afforestation but remained unchanged at about 1.27-1.29 kg/m2 after 52 ***,there were consistent increases in amino sugars and microbial residues with increasing stand *** stand age increased from 16 to 62 a,soil pH decreased from 6.84 to 5.71,and the concentration of total amino sugars increased from 178.53 to 509.99 mg/kg.A significant negative correlation between soil pH and the concentration of specific and total amino sugars was observed,indicating that the effects of soil acidification promote amino sugar stabilization during *** contrast to the Mongolian pine plantation of the same age,the cropland accumulated more SOC and microbial residues because of fertilizer *** Mongolian pine plantation with different ages,there was no significant change in calculated contribution of bacterial or fungal residues to SOC,suggesting that fungi were consistently the dominant contributors to SOC with increasing *** results indicate that afforestation in the Horqin Sandy Land promotes efficient microbial growth and residue accumulation in SOC stocks and has a consistent positive impact on SOC persistence.

关键词： soil organic matter stand age biomarker amino sugars microbial residues

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：