检索结果-南通市图书馆

Deforestation and fragmentation trends of seasonal dry tropical forest in Ecuador: impact on conservation

Forest Ecosystems 2021年第3期8卷 615-627页

作者： Carlos A.Rivas JoséGuerrero-Casado rafael m.navarro-cerillo Instituto de Ciencias Básicas Universidad Técnica de ManabíPortoviejoManabíEcuador Department of Forest Engineering Laboratory of DendrochronologySilviculture and Global Change–DendrodatLab–ERSAFUniversity of CordobaCampus de RabanalesCrta.IVkm.396E-14071 CordobaSpain Departamento de medicina Veterinaria Facultad de Ciencias VeterinariasUniversidad Técnica de ManabíPortoviejoManabíEcuador Department of Zoology University of CordobaCampus de Rabanales14071 CordobaSpain

Background:Fragmentation and deforestation are one of the greatest threats to forests,and these processes are of even more concern in the tropics,where the seasonal dry forest is possibly one of the most threatened ecosystems with the least remaining surface ***:The deforestation and fragmentation patterns that had occurred in Ecuadorian seasonal dry forests between 1990 and 2018 were verified,while geographic information systems and land cover shapes provided by the Ecuadorian ministry of the Environment were employed to classify and evaluate three types of seasonal dry forests:deciduous,semi-deciduous,and *** study area was tessellated into 10 km2 hexagons,in which six fragmentation parameters were measured:number of patches,mean patch size,median patch size,total edge,edge density and reticular fragmentation index(RFI).The RFI was also measured both outside and inside protected natural areas(unprotected,national protected areas and protected forest).moreover,the areas with the best and worst conservation status,connectivity and risk of disappearance values were identified by means of a Getis-Ord Gi*statistical ***:The deforestation of seasonal dry forests affected 27.04%of the original surface area still remaining in 1990,with an annual deforestation rate of−1.12%between 1990 and *** RFI has increased by 11.61%as a result of the fact that small fragments of forest have tended to disappear,while the large fragments have been fragmented into smaller *** semi-deciduous forest had the highest levels of fragmentation in *** three categories of protection had significantly different levels of fragmentation,with lower RFI values in national protected areas and greater values in protected ***:The seasonal dry forest is fragmenting,deforesting and disappearing in some *** increased protection and conservation of the Ecuadorian seasonal dry forest is,therefore,necessary owing to the fact that not all prot

关键词： Deciduous forest Semi-deciduous forest Remnant forest Patch isolation Habitat loss Protected areas

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

Disturbance and forest recovery in the monarch Butterfly Biosphere Reserve,mexico

引用

Journal of Forestry Research 2020年第5期31卷 1551-1566页

作者： Jose Lopez-Garcıa rafael m.navarro-Cerrillo Instituto de Geografıa Universidad Nacional Autonoma de MexicoCiudad UniversitariaC.P.04510 CoyoacanDFMexico Departamento de Ingenierıa Forestal Universidad de CordobaCampus de RabanalesCarretera Nacional IV km 39614014 CordobaSpain

Analysis of the change in forest cover is important to determine stand dynamics and the processes involved in disturbance and *** of the core zone of the monarch Butterfly Biosphere Reserve were studied using photo interpretation techniques,considering biennial changes between 1999 and 2013 and changes over the whole period of study 1999–*** matrices were elaborated to determine the processes of change involved in both recovery and *** biennial changes for the whole period amounted to 2274 ha;343 ha accounted as degraded in more than one biennial *** total changes in forest cover between 1999 and 2013 involved 4902 ha,out of which,2912 ha were affected by disturbance,and 1990 ha were *** density and 2013 vegetation cover maps,the overall accuracy was 95.6%and 90.2%,*** combining both maps,gradual processes were revealed that were not evident in separate *** methodology is useful for the management and conservation of natural protected areas.

关键词： Illegal logging Forest density change Forest recovery Conifer forests monarch Butterfly Biosphere Reserve

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

Amyloid-beta pathology-induced nanoscale synaptic disruption:the case of the GABA_B-GIRK assembly

引用

Neural Regeneration Research 2025年第5期20卷 1409-1410页

作者： rafael Lujan Alejandro martín-Belmonte Sergi Ferré Francisco Ciruela Synaptic Structure Laboratory Instituto de Biomedicina de la UCLM(IB-UCLM)Departamento de Ciencias MédicasInstituto de Investigación en Salud de Castilla-La Mancha(IDISCAM)Facultad de MedicinaUniversidad Castilla-La ManchaCampus BiosanitarioC/AlmansaAlbaceteSpain Integrative Neurobiology Section National Institute on Drug AbuseIntramural Research ProgramNational Institutes of HealthBaltimoreMDUSA Pharmacology Unit Department of Pathology and Experimental TherapeuticsSchool of Medicine and Health SciencesInstitute of NeurosciencesUniversity of BarcelonaNeuropharmacology&Pain GroupNeuroscience ProgramBellvitge Institute for Biomedical ResearchL’Hospitalet de LlobregatSpain

Alzheimer's disease (AD) is characterized by an imbalance between excitatory and inhibitory brain networks,leading to aberrant homeostatic synaptic *** has progressively been recognized as syna ptopathy and syna ptic dysfunction has been identified as a key component of its pathogenesis (Schirinzi et al.,2020).Syna ptic dysfunction is believed to precede synapse loss,a primary biological correlate of cognitive decline in AD,inevita bly associated with neuronal death.

关键词： Alzheimer pathology

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

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第2期10卷 112-119页

作者： manuel TORALIBAEZ margarita CARU miguel A. HERRERA Luis GONZALEZ Luis m. mARTIN Jorge mIRANDA rafael m. navarro-CERRILLO Department of Forest management Faculty of ForestryUniversity of Chile Santa Rosa 11315La PintanaSantiagoChile Department of Ecological Sciences Faculty of SciencesUniversity of ChileSanta Rosa 11315La PintanaSantiagoChile Department of Forestry School of Agriculture and Forestry University of Córdoba14080 CórdobaSpain Department of Genetic School of Agriculture and ForestryUniversity of Córdoba14080 CórdobaSpain Department of Forest management Faculty of ForestryUniversity of ChileSanta Rosa 11315La PintanaSantiagoChile

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was con- structed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGmA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geo- graphic origin.

关键词： Sequoia sempervirens (D. Don) Endl. Random amplified polymorphic DNAs (PCR-RAPDs) molecular markers Clone assays Chile Genetic relationships

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

Land cover changes and fragmentation in mountain neotropical ecosystems of Oaxaca, mexico under community forest management

引用

Journal of Forestry Research 2019年第1期30卷 143-155页

作者： rafael m~a navarro Cerrillo Dennis J.Esteves Vieira Susana Ochoa-Gaona Bernardus H.J.de Jong m~a del mar Delgado Serrano Depto. Ingeniería Forestal Laboratorio de SelviculturaDendrocronología y Cambio Climático.Dendrodat Lab-ERSAF Universidad de Córdoba Depto. de Engenharia Florestal Faculdade de Engenharia Florestal Laboratório de Sensoriamento Remoto e Geotecnologia Universidade Federal de Mato Grosso Departamento de Ciencias de la Sustentabilidad El Colegio de la Frontera Sur-Unidad Campeche Depto. Economía Sociología y Política Agrarias Grupo de Evaluación y Restauración de Sistemas Agrícolas y Forestales-ERSAF Universidad de Córdoba

Changes in land cover have a direct impact on forest ecosystem goods and services. In this study, changes in land cover in Sierra de Juarez–Oaxaca ecosystems were estimated using a consistent processing of Landsat images and OBIA methodology. Additionally, landscape analyses using FRAGSTAT were conducted. In 2014, Sierra de Juarez–Oaxaca was covered by approximately 84% of forests, mainly pine-oak and cloud forests. After extensive deforestation until 2001, this trend was reversed and the forest cover surface area in 2014 was slightly higher than in 1979. The comparison of the landscape structure of the forested and agricultural lands suggests an increase in habitat heterogeneity. However, interspersion and juxtaposition indices, showing the patch shape by patch area and perimeter, were similar throughout the study period(1979–2014). Social and economic drivers can explain this situation: namely, community organization, forest enterprises, payment for ecosystem services programs, and changes of agricultural activity. Communities in the Sierra of Oaxaca have reforested degraded lands, created community forest enterprises, and preserved the forest under conservation schemes like those proposed by the mexican payment for ecosystem services programs. However, their sustainable management faces internal challenges and has become highly dependent on political and institutional decisions beyond their control.

关键词： Tropical and temperate forests Social forestry Land uses segmentation OBIA FRAGSTAT

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

Distribution of malpighia mexicana in mexico and its implications for Barranca del Río Santiago

引用

Journal of Forestry Research 2021年第3期32卷 1095-1103页

作者： martín Tena meza rafael m.navarro-Cerrillo Diego Brizuela Torres Instituto de Botánica Centro Universitario de Ciencias Biológicas y AgropecuariasUniversidad de GuadalajaraMéxicoCamino Ramón Padilla Sánchez No.2100.Nextipac45200 ZapopanJaliscoMexico Depto.Ingeniería Forestal Laboratorio de SelviculturaDendrocronología y Cambio ClimáticoDendrodatLab-ERSAFUniversidad de CórdobaCampus de RabanalesCtra.N-IVkm.39614071 CórdobaSpain Departamento de Producción Forestal Centro Universitario de CienciasBiológicas y AgropecuariasUniversidad de GuadalajaraMéxicoCamino Ramón Padilla Sánchez No.2100 Nextipac45200 ZapopanJaliscoMexico

Wild plants represent relatively unexplored resource of high economic potential,especially as an alternative to developing new crops and,even more relevant,for improving existing crops and contributing to nutrition and *** wild species m alpighia mexicana(manzanita)has a wide tradition of food,medicinal and ornamental use in *** is part of the American-origin group of tropical shrubs that produce edible red fruits,such as A cerola,which is considered the most important natural source of vitamin C in the *** the role played by *** in mexico,and particularly in Barranca del Río Santiago(Santiago River Canyon),we modelled its potential distribution in both geographical *** used species'records from databases,local herbaria and records collected by the authors as well as climatic variables representing long term average,variability and extreme conditions of temperature and *** fit the models we used the modelling algorithm maxent and selected an adequate configuration by testing a range of model complexity *** results indicate a clear species preference for warm-dry tropical forest,most extensively in the Balsas river depression and the central valleys of *** probability of the species presence in the western region was also high,although the probability was also high for smaller surface areas,such as the region of Santiago river canyons,which are covered by warm-dry tropical forests.

关键词： malpighia mexicana maxent Warmdry tropical forest Río Santiago Genetic resources Ecological niche model manzanita

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

On the nonclassical dynamics of cavity-assisted four-channel nonlinear coupler

引用

Chinese Physics B 2018年第11期27卷 498-505页

作者： rafael Julius Abdel-Baset m A Ibrahim Pankaj Kumar Choudhury Hichem Eleuch Faculty of Applied Sciences Universiti Teknologi MARA (UiTM) Faculty of Applied Sciences Universiti Teknologi Mara (UiTM) Perak Tapah Campus Institute of microengineering and Nanoelectronics Universiti Kebangsaan Malaysia Department of Applied Sciences and mathematics College of Arts and Sciences Abu Dhabi University Institute for Quantum Science and Engineering Texas A&M University College Station

The non-classical properties of light propagating in four-channel Kerr waveguides, confined in an optical cavity, are studied. The solution to the Hamiltonian of field operators is obtained semi-analytically by using symmetrically ordered phase-space representation. Full quantum analysis of the input coherent fields displays a strong transition of photon property between the super-Poissonian and sub-Poissonian statistics. It is found that the cavity-assisted multichannel system exhibits enhanced squeezing both in single-and compound-mode. This multichannel system may be utilized as an efficient quantumlight generator.

关键词： squeezed states Kerr effects Langevin equation

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

Beacon-Less Geographic Routing in Real Wireless Sensor Networks

引用

Journal of Computer Science & Technology 2008年第3期23卷 438-450页

作者： Juan A.Sánchez rafael marín-Pérez Pedro m.Ruiz Department of Information and Communications Engineering University of MurciaSpain

Geographic Routing （GR） algorithms require nodes to periodically transmit HELLO messages to allow neighbors to know their positions （beaconing mechanism）. Beacon-less routing algorithms have recently been proposed to reduce the control overheads due to these messages. However, existing beacon-less algorithms have not considered realistic physical layers. Therefore, those algorithms cannot work properly in realistic scenarios. In this paper we present a new beacon-less routing protocol called BOSS. Its design is based on the conclusions of our open-field experiments using Tmote-sky sensors. BOSS is adapted to error-prone networks and incorporates a new mechanism to reduce collisions and duplicate messages produced during the selection of the next forwarder node. We compare BOSS with Beacon-Less Routing （BLR） and Contention-Based Forwarding （CBF） algorithms through extensive simulations. The results show that our scheme is able to *** almost perfect packet delivery ratio （like BLR） while having a low bandwidth consumption （even lower than CBF）. Additionally, we carried out an empirical evaluation in a real testbed that shows the correctness of our simulation results.

关键词： geographic routing beacon-less forwarding performance evaluation real deployment

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

multiple ecological strategies explain the distribution of exotic and native C_(4) grasses in heterogeneous early successional sites in Hawai’i

引用

Journal of Plant Ecology 2017年第3期10卷 426-439页

作者： rafael de Oliveira Xavier Carla m.D’Antonio Ecology and Conservation Lab Department of HydrobiologyFederal University of São CarlosWashington Luís Highwaykm 235São CarlosSão Paulo 13565-905Brazil Environmental Studies Program 4312-L Bren University of CaliforniaSanta BarbaraCA 93106USA

Aims Biotic homogenization results in novel communities contain-ing multiple exotic *** attributes that contribute to the dominance of invaders and increase invasibility of communities have been identified,but rarely have factors governing the domi-nance of co-occurring invaders been *** we assess the presence and performance of five exotic and one native C_(4) grass species across local(microsite)and more broad-scale variation in fire history,soil age,altitude and *** ask whether species show preferences for the same conditions,whether all are constrained by poor soil development,and how their performance changes when alone versus *** addition to providing information useful to managers who want to control some of these species,such information can help to predict how distributions might change with climate change methods We measured percent cover and plant height of each grass species in 64 plots in each of 15 sites,located in young volcanic substrates across environmental gradients in Hawai’i Volcanoes National Park,Hawai’i,*** varied in fire history and soil age,across altitu-dinal and precipitation *** estimated microsite heteroge-neity by measuring rock cover and soil depth,where each species was present and in plots as a *** analyzed effects of pos-sible controlling variables using chi-square tests and Generalized Additive mixed *** Findings Two species(Schizachyrium condensatum and Hyparrhenia rufa)were absent in shallow soil,restricted to more mesic sites and showed increasing performance with soil *** contrast,two other species(Andropogon virginicus and melinis repens)tended to occur in shal-low soil with high rock cover across a wide range of *** addi-tional species(melinis minutiflora)was weakly affected by soil depth and was the dominant at higher elevation(more mesic)and on burned sites,especially in old *** species was largely absent from lower elevation si

关键词： elevation gradient fire invasive species melinis minutiflora soil depth

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

TWO NOVEL GRADIENT mETHODS WITH OPTImAL STEP SIZES

引用

Journal of Computational mathematics 2021年第3期39卷 375-391页

作者： Harry Oviedo Oscar Dalmau rafael Herrera Centro de Investigacion en matematicas CIMAT A.C.GuanajuatoGto.Mexico

In this work we introduce two new Barzilai and Borwein-like steps sizes for the classical gradient method for strictly convex quadratic optimization *** proposed step sizes employ second-order information in order to obtain faster gradient-type *** step sizes are derived from two unconstrained optimization models that involve approximate information of the Hessian of the objective function.A convergence analysis of the proposed algorithm is *** numerical experiments are performed in order to compare the efficiency and effectiveness of the proposed methods with similar methods in the ***,it is observed that our proposals accelerate the gradient method at nearly no extra computational cost,which makes our proposal a good alternative to solve large-scale problems.

关键词： Gradient methods Convex quadratic optimization Hessian spectral properties Steplength selection

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

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：