检索结果-南通市图书馆

维普期刊数据库

Construction of Dulac functions for mathematical models in population biology

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2015年第3期8卷 135-154页

作者： Osvaldo osuna Cruz Vargas-De-Leon Instituto de Fisica y Matematicas Universidad MichoacanaEdif. C-3 Cd. Universitaria CP 58040 Morelia Michoacan Mexico Unidad de Medicina Experimental Hospital General de Mexico "Dr. Eduardo Liceaga" DF 06726 Mdxieo

In this paper, we present a method for constructing a Dulac function for mathematical models in population biology, in the form of systems of ordinary differential equations in the plane.

关键词： Population models epidemic models chemostat models Dulac function nonexistence of periodic orbits.

Priority areas for watershed service conservation in the Guapi-Macacu region of Rio de Janeiro,Atlantic Forest,Brazil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2014年第1期3卷 95-115页

作者： Vanesa Rodriguez osuna Jan Borner Udo Nehren Rachel Bardy Prado Hartmut Gaese Jurgen Heinrich Center for Development Research(ZEF) Department of Economic and Technological ChangeUniversity of BonnWalter-Flex-Str.353117 BonnGermany Institute for Technology and Resources Management in the Tropics and Subtropics(ITT) Cologne University of Applied SciencesBetzdorfer Str.250679 CologneGermany Empresa Brasileira de Pesquisa Agropecuária(EMBRAPA Soils) Brazilian Enterprise for Agricultural ResearchGeotechnologies and Environmental MonitoringRua Jardim BotanicoCEP 22460-000 Rio de JaneiroBrazil Institute for Geography Department of Physical GeographyUniversity of LeipzigJohannisallee 19a04103 LeipzigGermany

Introduction:Land use intensification and urbanisation processes are degrading hydrological ecosystem services in the Guapi-Macacu watershed of Rio de Janeiro.A proposal to pay farmers to restore natural watershed services might be an alternative to securing the water supply in the long-term for the around 2.5 million urban water users in the study *** study quantifies the costs of changing current land use patterns to enhance watershed services and compares these costs to the avoided costs associated with water treatment for public ***:We use farm-household data to estimate the opportunity costs of abandoning current land uses for the recovery of natural vegetation;a process that is very likely to improve water quality in terms of turbidity due to reduced inputs from *** cost estimates are extrapolated to the watershed scale based on remote sensing land use classifications and vulnerability analysis to identify priority zones for watershed management *** assess the potential demand for watershed services,we analyse water quality and treatment cost data from the main local water treatment ***:Changing agricultural land uses for watershed services provision generally comes at high opportunity costs in our study area near to the metropolis of Rio de *** low cost watershed conservation options do exist in the livestock production *** options have the potential to directly reduce the amount of sediments and nutrients reaching the water bodies,and in turn decrease the costs of treatment needed for drinking *** cover changes at the scale needed to improve water quality will,nonetheless,likely exceed the cost of additional investments in water ***:The state water utility company’s willingness to pay for watershed services alone will not be enough to induce provision of additional watershed *** conclude that monetary incentives conditioned on specific adjustme

关键词： Water services Drinking water treatment Water quality Incentive-based watershed management

China in the past 100 years

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Voice of Friendship 2021年第3期 38-39页

作者： Jesus osuna Sanz Spain-China Friendship Association

July 1 is the official anniversary of the Communist Party of China,but the first national congress of the CPC was held from July 23 to August 3,*** quarters of a century ago,in February 1948,the first edition of the M... 详细信息

关键词： anniversary Communist congress

Alginate modifies the physiological impact of CeO2nanoparticles in corn seedlings cultivated in soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第2期26卷 382-389页

作者： Lijuan Zhao Jose R.Peralta-Videa Bo Peng Susmita Bandyopadhyay Baltazar Corral-Diaz Pedro osuna-Avila Milka O.Montes Arturo A.Keller Jorge L.Gardea-Torresdey Chemistry Department The University of Texas at El Paso 500 West University Avenue University of California Center for Environmental Implications of Nanotechnology The University of Texas at El Paso 500 West University Avenue Environmental Science and Engineering PhD program The University of Texas at El Paso 500 West University Avenue Department of Biological Sciences The University of Texas at El Paso 500 West University Avenue Universidad Aut'onoma De Ciudad Ju'arez Plutarco Elias Calles # 1210 Fovissste Chamizal. Ciudad Juarez Chihuahua 32310 Mexico Chemistry Department University of Texas of the Permian Basin Odessa Bren School of Environmental Sciences and Management 3420 Bren Hall University of California

Alginates are naturally occurring components of organic matter in natural soil whose effects on nanoparticle （NP） toxicity to plants is not well understood. In the present study, corn plants were grown for one month in soil spiked with 400 mg/kg CeO2 NPs with various alginate concentrations. After one month of growth in the NPs impacted soil, plants were harvested and analyzed for Ce and mineral element concentrations. Chlorophyll concentration and heat shock protein 70, used as biomarkers for oxidative stress, were also evaluated. Results showed that, compared to CeO2 NPs treatment, alginate at 10, 50, and 100 mg/kg increased Ce concentration in roots by approximately 46%, 38%, and 29% and by 115%, 45%, and 56% in shoots, respectively. CeO 2 NPs without alginate increased Mn accumulation in roots by 34% compared to control. CeO2 NPs with low and medium alginate increased Mn by ca. 92% respect to NPs without alginate and by ca. 155% respect to control. CeO2 NPs without/with alginate significantly increased accumulation of Fe and Al in roots. In addition, alginate at 50 mg/kg increased Zn accumulation in roots by 52% compared to control. In shoots, K increased at all NP treatments but the accumulation of other elements was not affected. Alginate enlarged the impact of CeO2 NPs to corn plants by reducing chlorophyll a content and triggering overexpression of heat shock protein 70.

关键词： CeO2 NPs alginate nutrient uptake chlorophyll heat shock protein

维普期刊数据库

Mineralogical signatures and sources of recent sediment in a large tropical lake

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2018年第2期33卷 183-190页

作者： Jorge Feliciano Ontiveros-Cuadras Ana Carolina Ruiz-Fernández Joan-Albert Sanchez-Cabeza Libia Hascibe Pérez-Bernal Michel Preda Federico Páez-osuna Polytechnic University of Sinaloa (UPSIN) Mazatlan Academic Unit Institute of Marine Sciences and LimnologyNational Autonomous University of Mexico (UNAM) Oceanic and Coastal Processes Academic Unit Institute of Marine Sciences and LimnologyNational Autonomous University of Mexico (UNAM).University City Department of Earth and Atmospheric Sciences University of Quebec in Montreal (UQAM)

Two lead-210(210Pb) dated sediment cores from Chapala Lake were studied to identify the mineral composition of the sediments and to discuss its relation with trace metals. Minerals and trace metals reflected the domain of volcanic rocks(i.e. basalts, rhyolite and andesite) that characterize Chapala Lake and the Lerma River watershed. Redundancy analyses(RDA) were used to identify the sedimentary variables(magnetic susceptibility, organic matter, sand content, and mineral composition) that could be related to elemental composition. Despite the distance between the two cores(7.3 km) and hydrodynamic circulation the RDA showed that the main mechanism that controls the input of mineral species,and, therefore, element distributions in the lacustrine sediment of Chapala Lake, is related to the weathering of volcanic rocks in the Lerma-Chapala watershed, the consequent runoff and transport of fine grained catchment materials, and later in-lake processes. These findings highlight the importance of controlling watershed erosion to contribute to the improvement of the environmental quality of the lake.

关键词： Chapala Lake Trace metals Mineralogy Lacustrine sediments

Phenotypic Variation among and within Three Peppers Species(Capsicum)from Mexico

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2021年第1期90卷 259-275页

作者： Carlos Eduardo Ornelas-Ramírez Sergio Hernández-Verdugo Jesús Enrique Retes-Manjarrez Angel Valdez-Ortiz Antonio Pacheco-Olvera Tomás osuna-Enciso Flor Porras Facultad de Agronomía Universidad Autónoma de SinaloaCuliacánSinaloa80000México Programa Regional de Posgrado en Biotecnología Facultad de Ciencias Químico-BiológicasUniversidad Autónoma de SinaloaCuliacánSinaloa80030México Centro de Investigación en Alimentación y Desarrollo A.C.Unidad Culiacán CuliacánSinaloa80110México

The phenotypic variation and its distribution among species,morphotypes,and among and within populations was estimated in 71 populations pertaining to 15 morphotypes of three domesticated species of Capsicum from *** were made in the states of Sinaloa,Nayarit,Oaxaca,Tabasco,and Yucatán in two agroecosystems:Backyard-garden and *** phenotypic characteristics were analyzed through one-way variance analysis and multivariate analyses of principal components analysis(PCA)and hierarchical clustering using Ward’s *** study was performed in a uniform greenhouse experiment.A high variation was found among and within populations in all the measured *** the total variation,13.0%was distributed among species,27.9%among morphotypes,8.1%among populations,and 51.0%within *** plants grew in a uniform environment,these results indicate that the differences observed among and within species,morphotypes,and populations have a genetic *** and multivariate analyses clearly differentiated morphotypes,suggesting that the category of morphotypes must be used to nominate the infraspecific variation in the domesticated *** principal components analysis identified a total of 15 principal components that contributed to explain the total *** first two components explained 59.64%of the total variation and seven components explained more than 90%of the total *** the measured characteristics,number of seed per fruit,weight of the fruit,width of the fruit,length of the fruit,stem diameter,days to flowering,and height of the plant contributed to component 1 variation,whereas width of the leaf,length of the leaf,and number of locules,number of fruits and number of seeds per plant contributed to component *** hierarchical clustering separated the populations and the morphotypes in two large different *** group consisted of populations collected in monoculture conditions and the oth

关键词： Phenotypic variation Capsicum annuum Capsicum chinense Capsicum frutescens morphotype

Comparing the biogeochemical functioning of two arid subtropical coastal lagoons:the effect of wastewater discharges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2021年第1期7卷 49-60页

作者： Julio Medina-Galván Carmen Cristina osuna-Martínez Gustavo Padilla-Arredondo Martín Gabriel Frías-Espericueta Ramón Héctor Barraza-Guardado JoséAlfredo Arreola-Lizárraga Facultad de Ciencias del Mar Universidad Autónoma de SinaloaMazatlánMéxico Programa de Planeación Ambiental y Conservación Centro de Investigaciones Biológicas del NoroesteS.C.GuaymasMéxico Departamento de Investigaciones Científicas y Tecnológicas de la Universidad de Sonora HermosilloMéxico

Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly *** processes were evaluated with the LOICZ *** time was<2 days in both *** fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the *** showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm *** fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal *** and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the *** dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.

关键词： Coastal lagoons nutrient budgets net ecosystem metabolism Gulf of California

Transcriptome-wide mapping of pea seed ageing reveals a pivotal role for genes related to oxidative stress and programmed cell death

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transcriptome-wide mapping of pea seed ageing reveals a pivo...

生态文明建设中的植物学：现在与未来——中国植物学会第十五届会员代表大会暨八十周年学术年会

作者： Hongying Chen Louise Colville Daniel osuna Ilse Kranner Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of Sciences Seed Conservation Department Royal Botanic Gardens Departamento de Fisiología Vegetal Centro Hispano-Luso de Investigaciones Agrarias(CIALE)Facultad de Biología.Universidad de SalamancaC/Río Duero 1237185 SalamancaSpain

Understanding of seed ageing,which leads to viability loss during storage,is vital for ex situ plant conservation and agriculture *** the potential for regulation at the transcriptional level has not been fully ***,we studied the relationship between seed viability,gene expression and glutathione redox status during artificial ageing of pea(Pisum sativum) ***-wide analysis using microarrays was complemented with qRT-PCR analysis of selected genes and a multilevel analysis of the antioxidant *** degradation of DNA and RNA occurred from the onset of artificial ageing at 60% RH and 50℃,and transcriptome profiling showed that the expression of genes associated with programmed cell death,oxidative stress and protein ubiquitination were altered prior to any sign of viability *** 25 days of ageing viability started to decline in conjunction with progressively oxidising cellular conditions,as indicated by a shift of the glutathione redox state towards more positive values(>-180 mV).The unravelling of the molecular basis of seed ageing revealed that transcriptome reprogramming is a key component of the ageing process,which influences the progression of programmed cell death and decline in antioxidant capacity that ultimately lead to seed viability loss.

关键词： seed ageing programmed cell death glutathione transcriptome

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

狗切口抗菌敷料和术前PI消毒效果比较

国外兽医学（畜禽疾病） 1993年第3期4卷 23-26页

作者： Debora J osuna 马保华

本文比较了醇消毒1分钟后使用粘性抗菌敷料与吡咯烷酮一碘(Povidone-iodine,PI)进行狗术前皮肤消毒的抗菌效果。两法均用于15只成年狗两体侧皮肤的剪毛区域。皮肤消毒前、后立即及1hr后均测定皮肤细菌数。皮肤的主要细菌用拭子采集。计... 详细信息

本文比较了醇消毒1分钟后使用粘性抗菌敷料与吡咯烷酮一碘(Povidone-iodine,PI)进行狗术前皮肤消毒的抗菌效果。两法均用于15只成年狗两体侧皮肤的剪毛区域。皮肤消毒前、后立即及1hr后均测定皮肤细菌数。皮肤的主要细菌用拭子采集。计算消毒后立即及1hr后的细菌减少百分数、阴性培养结果百分数、大于5个菌落形成单位的百分数及皮肤反应率并统计分析。主观评价敷料粘性。与人医比较,两法的细菌数均显著减少,而敷料的效果则显著低于PI。66％的敷料发生翘起但与高细菌数无关。PI消毒后严重皮炎发生率较高。两法间皮肤潜在消源体的出现没有差异。作者认为,用醇确毒1分钟后使用抗菌敷料对于减少狗皮肤细菌数而言不如PI消毒有效。

关键词：犬病抗菌敷料消毒吡咯烷酮-碘

维普期刊数据库