检索结果-南通市图书馆

Sub-stand diameter distribution types vary along an old-growth Douglas-fir chronosequence into the horizontal diversification development stage

引用

Journal of Forestry Research 2023年第2期34卷 415-424页

作者： JeriLynn E.Peck Eric K.Zenner Department of ecosystem science and management The Pennsylvania State UniversityUniversity ParkPA 16802USA

Managing mature Douglas-fir[Pseudotsuga menziesii(Mirb.)Franco]stands to emulate the structural complexity of natural old-growth forest requires identifying structural targets at the sub-stand level at which neighborhood dynamics and patchy disturbance shape *** therefore sought to describe the archetypal shapes of predominant sub-stand diameter distribution types(DDTs)observed in natural tree neighborhoods in stands comprising a chronosequence(ca.120-450+yrs)encompassing mature,vertical diversification,and horizontal diversification development *** ten 1.0 ha stands are located in the southcentral Oregon Cascades,*** on the known spatial position of each tree,natural tree neighborhoods were identified using the floating neighborhood approach based on spatial tessellation connecting neighboring trees at the first-(mean 61 m2)through fifth-(mean 2058 m2)order *** analysis was then used to objectively identify the most predominant DDTs among the relative tree size distributions observed in the trans-scale neighborhoods within each *** measures regression was used to classify each DDT to one of six observed archetypal shapes:negative exponential,unimodal,rotated sigmoid,bimodal,concave,or *** three of the 81 observed DDTs deviated by50%(maximum 83%).Within each stand,five to ten predominant DDTs were observed,which deviated from the stand average by 30-48%and were characterized by two to five different archetypal ***,in some stands the majority of tree neighborhoods were best characterized by a different shape from that assigned at the stand *** from the stand average increased from the youngest stand in the mature development stage through the middle stands in the vertical diversification stage to the oldest stands in the horizontal diversification *** complexity of DDT shapes tended to increas

关键词： Diameter distribution type Floating neighborhood Restoration silviculture Small-scale Structural complexity

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

Relationship between apparent redox potential discontinuity (aRPD) depth and environmental variables in soft-sediment habitats

引用

International Journal of Sediment Research 2017年第4期32卷 472-480页

作者： Travis G.Gerwing Alyssa M.Allen Gerwing Kieran Cox Francis Juanes Sarah E.Dudas ecosystem science and management program University of Northern British Columbia Department of Biology University of Victoria Department of Biology Vancouver Island University

As global temperatures increase and dissolved oxygen(DO) content decreases in marine systems, indices assessing sediment DO content in benthic habitats are becoming increasingly useful. One such measure is the depth to the apparent redox potential discontinuity(aRPD), a transition of sediment color that serves as a relative measure of sediment DO content. We examined spatiotemporal variation of aRPD depth, and the nature of the relationships between aRPD depth and biotic(infauna and epibenthic predators) and abiotic variables(sediment properties), as well as the availability of resources(chlorophyll a concentration, and organic matter content) in the intertidal mudflats of the Bay of Fundy, Canada. aRPD depth varied significantly through space and time, and a combination of biotic(sessile and errant infauna, as well as epibenthic predators), and abiotic(exposure time of a plot, sediment particle size,penetrability, and water content) variables, as well as the availability of resources(sediment organic matter content, and chlorophyll a concentration) were correlated with aRPD depth. As such, knowledge of both biotic and abiotic variables are required for a holistic understanding of sediment DO *** variables likely dictate a suite of potential aRPD depth conditions, while biota and resource availability, via bioturbation and respiration, strongly influence the observed aRPD depth. As DO conditions in marine systems will continue to change due to global climate change, elucidating these relationships are a key first step in predicting the influence decreasing DO content may have upon marine benthos.

关键词： Relationship between apparent redox potential discontinuity depth and environmental variables in soft-sediment habitats DO

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Alkaline leaching mechanism of MSWI bottom ash: the pivotal role of Si(Al) chemical bonding environments

引用

science China Technological sciences 2025年

作者： Ningning SHAO Zekun JIAO Weipeng FENG Yu JIN Fanlong KONG Zhijun DONG Zuotai ZHANG Institute of Technology for Marine Civil Engineering Shenzhen Institute of Information Technology (SZIIT) Guizhou NASH Ecological Technology Co. LTD School of Environmental science and Engineering Key Laboratory of Municipal Solid Waste Recycling Technology and Management of Shenzhen City Southern University of Science and Technology (SUSTech)

Municipal solid waste incineration bottom ash(MSWIBA) is a complex assemblage of aluminosilicate materials encompassing diverse solid wastes. Thus, its complexity poses great challenges to their resource utilization. For the sake of the alkali activation use of MSWIBA, this work focused on the characterizations and alkaline leaching experiments of various classified MSWIBA after sorting. Among the different categories of MSWIBA, waste glass(BA-G) and other unidentified slags(BA-O) were identified as potential precursors for alkali activation use. The alkaline leaching experiments proved that alkaline concentration, reaction temperature, reaction time, and raw material classification influenced the leaching process and results. Among these, the Si/Al chemical bonding environments from the material type played a pivotal role. When the materials had Qn(n>2) as the primary bonding structure, steric hindrance by the chain frameworks affected the alkali dissolution process, resulting in gradual disintegration from the outer layers inward. For the materials dominated by Q1frameworks, OH-could penetrate the frameworks, leading to their rapid depolymerization and outward dissolution. Overall, the Si/Al bonding environment played a crucial role in alkaline dissolution, providing theoretical guidance for classifying the alkali-activation utilization of MSWIBA and other aluminosilicate solid wastes.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Discrete Numerical Study on Type II Fracture of Partially Detached Concrete Panels in Cold Region

引用

Structural Durability & Health Monitoring 2025年第1期19卷 167-191页

作者： Huayi Zhang Maobin Song Lei Shen Nizar Faisal Alkayem Maosen Cao College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210024China Haihe River Huaihe River and Xiaoqinghe River Basin Water Conservancy Management and Service Center of Shandong ProvinceJinan250100China College of Mechanics and Engineering science Hohai UniversityNanjing211100China

When the upper chord beam of the beam-string structure(BSS)is made of concrete-ﬁlled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on the design of the tensioning plans and selection of control measures for the *** order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during con-struction,the inﬂuence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of concrete,and friction coefﬁcient on the bending stiffness are analyzed parametrically by the numerical simula-tion technology based on an actual *** calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical ***,the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS,respectively,and the mechanical properties such as prestress-tensioning control value,structural deformation,and internal force of key members are comparatively analyzed when adopting two different construction ***,the optimal construction plan of concrete placementﬁrst and then prestress-tensioning is proposed.

关键词： Beam-string structure(BSS) concrete-ﬁlled steel tube(CFST) bending stiffness timing of concrete placement prestress-tensioning

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

A Latency-Aware and Fault-Tolerant Framework for Resource Scheduling and Data management in Fog-Enabled Smart City Transportation Systems

引用

Computers, Materials & Continua 2025年第1期82卷 1377-1399页

作者： Ibrar Afzal Noor ul Amin Zulfiqar Ahmad Abdulmohsen Algarni Department of Computer science and Information Technology Hazara UniversityMansehra21300Pakistan Department of Computer science King Khalid UniversityAbha61421Saudi Arabia

Thedeployment of the Internet of Things(IoT)with smart sensors has facilitated the emergence of fog computing as an important technology for delivering services to smart environments such as campuses,smart cities,and smart transportation *** computing tackles a range of challenges,including processing,storage,bandwidth,latency,and reliability,by locally distributing secure information through end *** of endpoints,fog nodes,and back-end cloud infrastructure,it provides advanced capabilities beyond traditional cloud *** smart environments,particularly within smart city transportation systems,the abundance of devices and nodes poses significant challenges related to power consumption and system *** address the challenges of latency,energy consumption,and fault tolerance in these environments,this paper proposes a latency-aware,faulttolerant framework for resource scheduling and data management,referred to as the FORD framework,for smart cities in fog *** framework is designed to meet the demands of time-sensitive applications,such as those in smart transportation *** FORD framework incorporates latency-aware resource scheduling to optimize task execution in smart city environments,leveraging resources from both fog and cloud *** simulation-based executions,tasks are allocated to the nearest available nodes with minimum *** the event of execution failure,a fault-tolerantmechanism is employed to ensure the successful completion of *** successful execution,data is efficiently stored in the cloud data center,ensuring data integrity and reliability within the smart city ecosystem.

关键词： Fog computing smart cities smart transportation data management fault tolerance resource scheduling

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

Depth to the apparent redox potential discontinuity(aRPD)as a parameter of interest in marine benthic habitat quality models

引用

International Journal of Sediment Research 2018年第2期33卷 149-156页

作者： Travis G.Gerwing Kieran Cox Alyssa M.Allen Gerwing Charmaine N.Carr-Harris Sarah E.Dudas Francis Juanes ecosystem science and management program University of Northern British Columbia Department of Biology University of Victoria Skeena Fisheries Commission 4. Department of Biology Vancouver Island University

The usefulness of the apparent redox potential discontinuity(aRPD) in assessments of marine benthic habitat quality was explored at two intertidal mudflats along the north Pacific coast of Canada. Two transects were established at each intertidal site, with three sediment biogeochemistry cores collected from each transect four times over the summer of 2016. Measurements of the sediment pore water dissolved oxygen(DO) content and redox(Eh) conditions were taken at the surface of the core(measured vertically), as well as at increasing depths(1 cm between readings) into the sediment(measured horizontally through predrilled holes in the biogeochemistry corer). While oxic, anoxic, oxidized, and reduced sediment pore water was observed above and below the aRPD, in general, sediment above the aRPD had higher DO content, and higher Eh values than sediment below the aRPD. Therefore, the aRPD depth can be used as a relative indicator of sediment pore water DO and Eh conditions: sediment with a deeper aRPD depth has more available DO, and the pore water has higher Eh values(more oxidized or less reduced) than sediment with a shallower aRPD depth. As such, the aRPD depth is a useful parameter to include in models that assess the quality of marine benthic habitats.

关键词： Anoxia Apparent redox potential discontinuity(aRPD) Dissolved oxygen Habitat quality Hypoxia Intertidal Marine benthos Sediment pore water

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Levels of Germinable Seed in Topsoil and Yak Dung on an Alpine Meadow on the North-East Qinghai-Tibetan Plateau

引用

Journal of Integrative Agriculture 2013年第12期12卷 2243-2249页

作者： YU Xiao-jun XU Chang-lin WANG Fang SHANG Zhan-huan LONG Rui-jun College of Grassland science Gansu Agricultural University/Key Laboratory of Grassland EcosystemMinistry of Education/Sino-U.S.Center for Grassland Ecosystem Sustainability College of Agronomy Gansu Agricultural University International Centre for Tibetan Plateau ecosystem management Lanzhou University

In order to clarify the interactive mechanism between grazing yak and alpine meadow on the Qinghai-Tibetan Plateau,our study assessed seed density（by species） in the topsoil of alpine meadow with different grazing intensities in the Tianzhu area,north-eastern margins of the Qinghai-Tibetan Plateau and their rates of occurrence in yak *** density in the topsoil of the lightly grazed,moderately grazed,heavily grazed and extremely grazed alpine meadows in November,2010 were 1 551,1 692,2 660 and 1 830 grains m-2,while in the same meadows in April,2011 densities were 1 530,2 404,2 530 and 2 692 grains m-2,*** the cold season pasture,mean seed density in yak dung from November to April in the lightly grazed,moderately grazed,heavily grazed and extremely grazed sites were 121,127,187,and 120 grains kg-1of dry yak *** proportion of total seed numbers in yak dung to soil seed bank in lightly grazed,moderately grazed,heavily grazed and extremely grazed alpine meadow was 1.40,2.62,0.69,and 0.90%.12 species out of the 47 were not found in topsoil but were found in yak dung,10 species out of 45 were not found in yak dung but were found in the *** dispersal by yaks is therefore very important for soil seed bank and plant biodiversity and population dynamics in alpine meadows.

关键词： alpine meadow seeds endozoochory seed density soil seed bank yak dung

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

Epiphytic orchids and their ecological niche under anthropogenic influence in central Himalayas,Nepal

引用

Journal of Mountain science 2016年第5期13卷 774-784页

作者： ADHIKARI Yagya Prasad FISCHER Anton FISCHER Hagen Siegfried Geobotany Department of Ecology and Ecosystem ManagementTechnische Universit?t München

The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions：（1） What is the ecological niche of the different epiphytic orchid species？（2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （PCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.

关键词： Host characteristics Epiphytic orchids Anthropogenic disturbances Canopy ecosystem Ecological niche Himalayas

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

FHL2 deficiency aggravates Candida albicans infection through decreased myelopoiesis

引用

science China Life sciences 2025年

作者： Rongmei Gao Kanchao Chen Yimin Wang Rongxia Guo Xiaoyu Zhang Peng Wu Weili Wang Qingxiang Huang Xuemei Xie Shangda Yang Yanling Lü Qian Ren Fei Liu Song Chen Fengxia Ma Tao Cheng Hui Cheng State Key Laboratory of Experimental Hematology National Clinical Research Center for Blood Diseases Haihe Laboratory of Cell Ecosystem Institute of Hematology & Blood Diseases Hospital Chinese Academy of Medical Sciences & Peking Union Medical College CAMS Center for Stem Cell Medicine PUMC Department of Stem Cell and Regenerative Medicine

Hematopoiesis is a finely tuned process that generates all blood cell types through self-renewal and differentiation, which is crucial for maintaining homeostasis. Acute infections can prompt a hematopoietic response known as emergency myelopoiesis. In this study, using a Candida albicans (C. albicans) infection model, we demonstrated for the first time that disruption of Fhl2 led to increased fungal burden,heightened inflammatory response and reduced survival rates. Impaired myeloid hematopoiesis and immune cell production were evident, as proved by the decreased numbers of hematopoietic stem and progenitor cells (HSPCs) and granulocytes in the bone marrow of Fhl2-deficient mice. In conclusion, FHL2 regulated emergency myelopoiesis in response to C. albicans, affecting the host’s defense against pathogens.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Mitigating People-Park Conflicts on Resource Use through Ecotourism:A Case of the Nanda Devi Biosphere Reserve,Indian Himalaya

引用

Journal of Mountain science 2011年第1期8卷 87-95页

作者： Chandra Prakash KALA Rakesh Kumar MAIKHURI ecosystem and Environment management Indian Institute of Forest Management G.B.Pant Institute of Himalayan Environment and Development Post.

Eeotourism aims to deliver the philosophy of sustainable development through environmental conservation as well as socio-economic development. Areas with rich biodiversity and scenic beauty, like the Indian Himalayan region, have been one of the major destination centers for nature lovers from historical time. In view of conserving the rich biodiversity and natural heritage of the Himalayan region 92 protected areas have been set aside, of these Nanda Devi Biosphere Reserve （NDBR） is a well known world heritage site. Over a period of time establishing NDBR has invited conficts between the local people and reserve authorities on the management approaches and utilization criteria of the natural resources, especially banning the traditional bio-resource collection rights of local community, expeditions, trekking, and other anthropogenic activities in the core zones. The present study aims to understand and analyze the various people - park conflicts, and also to suggest ways to mitigate such conflicts in view of biodiversity conservation and improvement of economic status of local people by promoting eeotourism. With this view the study further discusses the various aspects of eeotourism, its pros and cons, and the avenues of developing appropriate strategies for promotion of ecotourism in buffer zone areas of NDBR.

关键词： Eeo-tourism Indian Himalaya NandaDevi Biosphere Reserve Nature conservation People-park conflicts

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：