检索结果-南通市图书馆

Environmental and Economic Impact of Forest Fires in Puerto Rico 2013-2014

在线全文

学校读者我要写书评

暂无评论

Open Journal of Forestry 2015年第4期5卷 353-363页

作者： Méndez-Tejeda Rafael Santos-Corrada maría Ortiz-Morales Sergio Claudio-vargas Oscar Natural Science Department Atmospherical Science Laboratory University of Puerto Rico—Carolina Campus Carolina Puerto Rico School of Business and Entrepreneurship University of Turabo Gurabo Puerto Rico

This study presents an analysis of the impact of forest fires in Puerto Rico for the period from 2013-2014. The climatological factors analyzed included precipitation, temperature, relative humidity, and wind. Several factors have combined to the increase of these forest fires, among others, a decrease in precipitation during this period, as well as an increase in the human involvement in these fires from approximately 40% occurs in the night period (5:00 pm to 8:00 am), where the weather conditions do not favor the appearance of these phenomena. An increase in fires of 44% occurred in 2013 compared to 2014, causing an economic loss of $13.8 million. Fire also adversely affected the flora and fauna of the island, but this was not evaluated in this paper.

关键词： Fires Forest Wildfire Economic Impact of Forest fires Precipitation and Weather Conditions

Impacts of fire severity and cattle grazing on early plant dynamics in old-growth Araucaria-Nothofagus forests

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2019年第4期6卷 298-311页

作者： Paola Arroyo-vargas Andres Fuentes-Ramírez Bart muys Aníbal Pauchard Laboratorio de Biometría Departamento de Ciencias ForestalesUniversidad de La FronteraCasilla 54-DTemucoChile Programa de Magíster en Manejo de Recursos Naturales Facultad de Ciencias Agropecuarias y ForestalesUniversidad de La FronteraCasilla 54-DTemucoChile Butamallin Research Center for Global Change Universidad de La FronteraTemucoChile Instituto de Ecología y Biodiversidad(IEB) SantiagoChile Department of Earth and Environmental Sciences University of LeuvenCelestijnenlaan 200EBox 24113001 LeuvenBelgium Laboratorio de Invasiones Biológicas(LIB) Facultad de Ciencias ForestalesUniversidad de ConcepciónCasilla 160-CConcepciónChile.

Background: Fire has historically shaped the dynamics of Araucaria araucana-Nothofagus pumilio forests in the Andean region of South America. Nevertheless, human disturbances and stronger drought events have resulted in increased occurrence and severity of wildfires. Regardless of their conservation relevance, the initial response to fire of Araucaria-Nothofagus forests has not been well documented. Through this research we tested the hypothesis that plant composition of Araucaria-Nothofagus forest after fire will initially differ in its recovery depending on fire severity, but over time, plant similarity will increase among areas with different levels of fire severity. The study was carried out in old-growth Araucaria-Nothofagus forests in south-central Chile(38°S) that were burned in 2015. We studied vegetation response to three levels of fire severity(low(LS), moderate(MS) and high(HS) severity), also including an adjacent unburned forest(UN), which were assessed one, two and three years after fire. We also evaluated the impact of cattle on plant recovery after fire. We measured species richness, abundance, plant diversity and origin of all vascular plant ***: Species richness and plant abundance responded differently to fire severity. Time-since-fire had a significant effect on plant richness and abundance. Plant composition within LS areas was similar to UN areas, but MS and HS areas were significantly less diverse compared to UN and LS. In absence of other major disturbances, similarity in plant composition tended to increase over time across the different levels of fire severity, becoming more similar to UN. We also found a synergetic effect of cattle and fire on species richness. This interaction promotes the establishment of nonnative species and limits the recovery of native species following ***: Fire severity had a significant impact on the plant community of old-growth Araucaria-Nothofagus forests,especially in areas of high fir

关键词： Fire severity gradient Wildfire Post-fire plant recovery Cattle exclusion Synergistic effects of disturbances Araucaria araucana Nothofagus pumilio

Song divergence indicates an unclear relationship between the Neotropical and Nearctic Horned Larks

在线全文

学校读者我要写书评

暂无评论

Avian Research 2021年第2期12卷 161-172页

作者： Jimmy Alexander vargas-Puentes Luis Alejandro Arias-Sosa Carolina Ramos-Montaño Grupo Ecología de Organismos(GEO-UPTC) Escuela de Ciencias BiológicasUniversidad Pedagógica Y Tecnológica de ColombiaTunjaColombia

Background:Some studies have indicated that the Horned Larks(Eremophila alpestris)should be considered as a species *** it split into four species or clades and seven subclades based on genetic,morphological,and biogeographic ***,other aspects like song divergence have not been studied and several subspe-cies have not been evaluated,leading to important information gaps in this group of *** this work,we aimed to assess the differences in song traits and playback response between the Nearctic subclade and the Neotropical or Colombian subspecies ***:We compared six song traits between these groups and performed field playback experiments,to test the response of the Neotropical larks to both *** tested the difference in the variables for separate as well as by principal component analysis(PCA).Results:We found significant differences(p<0.05)in the individual song traits and the PCA analysis between the two ***,the PCA analysis showed a clearer divergence of the Neotropical songs in comparison to the Nearctic songs of different locations within North ***,the playback analysis showed a significantly lower response of *** to the songs of the Nearctic ***:Besides this song divergence,there are important ecological and biogeographic differences between the Neotropical and Nearctic Horned Larks,that indicate an unclear relationship between these two ***,further morphological and genetic studies are required to clarify the taxonomy of the Neotropical Horned Lark and define if they share the same evolutionary history as the other subspecies of the Nearctic subclade.

关键词： Birdsong Eremophila alpestris peregrina Song features Speciation Reproductive barrier

Exploring the size of Andean condor foraging groups along an altitudinal and latitudinal gradient in the Tropical Andes: Ecological and conservation implications

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2024年第2期70卷 225-232页

作者： Diego Mendez Felix Hernan vargas JoséHernan Sarasola Pedro P.Oleaa Departamento de Ecologia Universidad Autonoma de MadridCalle Darwin 228049MadridSpain museo Nacional de Historia Natural Calle 26 s/nCota CotaLa PazBolivia The Peregrine Fund 5668 West Flying Hawk LaneBoiseID 83709USA Centro para el Estudio y Conservacion de Aves Rapaces en Argentina(CECARA) Universidad Nacional de La PampaAvda Uruguay 1516300 Santa RosaLa PampaArgentina Instituto de las Ciencias Ambientales y de la Tierra de La Pampa(INCITAP-CONICET) Avda.Uruguay 1516300 Santa RosaLa PampaArgentina Centro de Investigacion en Biodiversidad y Cambio Global(CIBC-UAM) Universidad Autonoma de MadridMadridCalle Darwin 228049Madrid Snain

Patterns of variation in the size of vulture foraging groups,and their ecological causes and consequences,remain litle explored despite strong links with the carrion recycling service that this key functional group *** documented the group size-frequency pattern of Andean con-dors Vultur gryphus gathered to feed on 42 equine carcasses experimentally placed in Bolivia,between 2012 and 2019,along an elevation range of 1,300-4,500 m *** on the location(altitude and latitude)of the foraging groups,we examined the relationship between their size and species'population parameters(size and trend),habitat conditions,and livestock carcass availability and *** utilized a high frequency(93%)of carcasses forming groups that ranged from 1 to 80 individuals(mean=25,median=18)and shaped a"lazy-J curve"typical pattern of size-frequency distribution whereby few groups(5,12%)were large(>55 individuals)and most(21,50%)were relatively small(<19 individuals).Group size related to altitude in that most larger groups formed at lower sites(below c.3,000 m asl),likely following an altitudinal gradient whereby larger groups are more likely to form around larger carcasses(i.e.,cattle),which are more likely to occur at lower *** of population size,group size could be an adaptive response of condors via local enhancement for improving individual scavenging *** information gaps on this topic still exist,thus we provide a set of questions to address them,especially amidst the unrestricted impacts of human activities that condition vulture survival globally.

关键词： condor andino fusion-fission dynamics group size scavenger social foraging vultures.

Frugivory and seed dispersal in the Galápagos:what is the state of the art?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2011年第2期6卷 110-129页

作者： Ruben HELENO Stephen BLAKE Patricia JARAMILLO Anna TRAVESET Pablo vargas Manuel NOGALES Mediterranean Institute of Advanced Studies(CSIC-UIB) Terrestrial Ecology GroupMallorcaBalearic Islands Royal Botanical Garden Madrid(CSIC-RJB) Madrid Island Ecology and Evolution Research Group(CSIC-IPNA) TenerifeCanary IslandsSpain Max Planck Institute for Ornithology Vogelwarte RadolfzellRadolfzellGermany Charles Darwin Foundation Puerto AyoraSanta CruzGalapagosQuitoEcuador

The Galápagos are considered a model oceanic archipelago,with unique flora and fauna currently threatened by alien invasive *** dispersal is an important ecosystem function with consequences for plant population dynamics and vegetation ***,understanding the seed dispersal abilities of the assemblages of frugivores will inform scientists and managers of the dynamics of plant invasions and improve management *** we provide the first comprehensive review of published information on frugivory and animal seed dispersal in the Galá*** collected data from a variety of sources,including notes of the first naturalist expeditions,gray literature available only in Galápagos collections,and peer-reviewed journal ***–animal frugivorous interactions were retrieved from 43 studies and compiled into an interaction matrix describing 366 unique *** studies focused on fruit consumption as a driving force for natural selection,but seed fate was seldom *** most(71%)of the interactions involved native plants,more than one-quarter(28%)involved introduced *** involving birds are considerably more common than those of reptiles and mammals,probably reflecting a research bias towards *** the historical importance of the archipelago as the laboratory for evolutionary and ecological research,understanding of its seed dispersal systems is *** end the review by suggesting 3 priority areas of research on frugivory and seed dispersal in the Galápagos:(i)target research to close knowledge gaps;(ii)the use of a network approach to frame seed dispersal at the community level;and(iii)evaluation of the effect of seed dispersal as a selective pressure acting upon plants and ***,the output of this research has to be properly delivered to the Galápagos National Park Services to help increase management effectiveness.

关键词： conservation planning oceanic islands plant invasions plant-animal interaction seed predation

Galápagos land iguana(Conolophus subcristatus)as a seed disperser

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2016年第3期11卷 207-213页

作者： Anna TRAVESET Manuel NOGALES Pablo vargas Beatriz RUMEU Jens M.OLESEN Esporles Mallorca 07190Balearic IslandsSpain Island Ecology and Evolution Research Group(CSIC-IPNA) Instituto de Productos Naturales y Agrobiología38206 TenerifeCanary IslandsSpain Real Jardín Botánico(CSIC-RJB) Department of Biodiversity and ConservationPlaza de Murillo 228014 MadridSpain Centre for Functional Ecology Department of Life SciencesUniversity of CoimbraCalçada Martim de FreitasCoimbra 3000-456Portugal Institute of Bioscience Aarhus UniversityAarhusDenmark and 6Charles Darwin FoundationPuerto AyoraSanta CruzGalápagosQuitoEcuador

The role of the most common land iguana(Conolophus subcristatus)in the Galápagos Islands as an effective seed disperser is explored in this study.A total of 5705 seeds of 32 plant species were identified from 160 scats,4545 of which(80%)appeared visually *** trials of 849 seeds from 29 species revealed that at least 10 species remained viable after passing through the iguana’s gut,although only a small proportion of those seeds(4%)*** any case,we argue that *** exerts an important role on the 7 Galapagos islands where it occurs because of its abundance and capacity to ingest and disperse seeds at long *** results strongly suggest that the Galápagos *** plays an important role as a seed disperser of not only of native species but also some introduced plants in the Galápagos Islands.

关键词： Conolophus subcristatus Fernandina Island Galápagos Islands Saurochory seed dispersal

Purification and Partial Characterization of Polyphenol Oxidase from Sapodilla Plum (<i>Achras sapota</i>)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food and Nutrition Sciences 2013年第7期4卷 727-734页

作者： Jorge Tamayo Cortez Carlos Hernán Herrera Méndez Enrique Sauri Duch maría de Lourdes vargas y vargas Sara Solís Pereira Agroindustrial Engineering Department Campus Celaya-Salvatierra Universidad de Guanajuato Salvatierra Mexico. Research and Postgraduate Division Instituto Tecnológico de Mérida Merida Mexico

The browning of fruits can be considered as an enzymatic oxidation which is believed to be one of the main causes of quality loss during post-harvest handling. The enzymes responsible for this are the oxidoreductases;the polyphenol oxidase (PPO) (monophenol, o-diphenol, oxygen oxidoreductase;EC 1.***.18.1) belongs to this group. This enzyme, which is found in the sapodilla plum (Achras sapota), was purified using a phenylsepharose and a SephacrylS-200 columns. The molecular weight of the purified enzyme was estimated to be about 66 kDa by gel filtration and 29 kDa by SDS-PAGE. A single protein band was found using the latter system (SDS-PAGE), which shows that the PPO of the pulp of the sapodilla plum may be composed of two protein subunits with similar molecular weight. The optimum pH was 7.0 and the optimum temperature 60℃. The most effective inhibitors tested were ascorbic acid, sodium metabisulfite and acetic acid.

关键词： Enzymatic System Oxidation Polyphenol Oxidase Browning Process Nutritional Value

Preparation of Rod-like Aluminum Doped Zinc Oxide Powders by Sol-gel Technique Using Metal Chlorides and Acetylacetone Precursors

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 Wuhan University of Technology(Materials Science) 2018年第6期33卷 1293-1297页

作者： KESHTKAR Javad vargas GARCIA Jorge Roberto GALAVIZ PEREZ Jorge marTINEZ TRINIDAD José Escuela Superior de Ingenieria Mecánica y Eléctrica Instituto Politécnico NacionalMéxico07738CDMXMéxico Escuela Superior de Ingenieria Quimica e Industrias Extractivas Instituto Politécnico NacionalMéxico07738CDMXMéxico Universidad Juárez Autònoma de Tabasco DivisiònAcadémica Multidisciplinaria de Jalpa de MéndezRibera AltaJalpa de MéndezTabasco86205México

Al-doped ZnO(AZO) powders were prepared by using metal chloride precursors and the sol-gel technique. IR peaks observed at 1590 cm-1 and 1620 cm-1indicated the formation of metal chelate as a consequence of the addition of acetylacetone to the metal chloride solution. TG-DSC analysis of the AZO gels confirmed the formation of metal chelate as evidenced by the development of several weight loss peaks accompanied by the introduction of new endothermic peaks. The resulting AZO gels were annealed at 500, 600, and 800 ℃ to study the effect of annealing temperature. XRD and SEM results showed that crystallization of AZO gels takes place around 600 ℃. Hexagonal wurtzite structure was identified as the main phase for all the samples. In addition, small shift of the XRD(002) peak coupled with XPS results from the AZO powders confirmed the successful doping of the ZnO powders. Micron sized rod-like AZO powders were uniform in dimension and morphology and remained stable even at 800 ℃.

关键词： aluminum doped ZnO rod-like metal chloride sol gel acetylacetone

Depth to the bottom of magnetic layer in South America and its relationship to Curie isotherm,Moho depth and seismicity behavior

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2018年第1期9卷 93-107页

作者： Javier Idárraga-García Carlos A.vargas Research Group on Geophysics Universidad Nacional de ColombiaBogotáColombia Deportment of Geosciences.Universidad Nacional de Colombia.Bogota.Colombia

We have estimated the DBML（depth to the bottom of the magnetic layer） in South America from the inversion of magnetic anomaly data extracted from the EMAG2 grid. The results show that the DBML values, interpreted as the Curie isotherm, vary between -10 and -60 km. The deepest values（〉-45） are mainly observed forming two anomalous zones in the central part of the Andes Cordillera. To the east of the Andes, in most of the stable cratonic area of South America, intermediate values（between -25 and-45 km） are predominant. The shallowest values（〈-25 km） are present in northwestern corner of South America, southern Patagonia, and in a few sectors to the east of the Andes Cordillera. Based on these results, we estimated the heat flow variations along the study area and found a very good correlation with the DBML. Also striking is the observation that the thermal anomalies of low heat flow are closely related to segments of flat subduction, where the presence of a cold and thick subducting oceanic slab beneath the continent, with a virtual absence of hot mantle wedge, leads to a decrease in the heat transfer from the deeper parts of the *** comparing our results with the Moho depths reported by other authors, we have found that the Curie isotherm is deeper than Moho in most of the South American Platform（northward to -20°S）, which is located in the stable cratonic area at the east of the Andes. This is evidence that the lithospheric mantle here is magnetic and contributes to the long wavelength magnetic signal. Also, our results support the hypothesis that the Curie isotherm may be acting as a boundary above which most of the crustal seismicity is concentrated. Below this boundary the occurrence of seismic events decreases dramatically.

关键词： Magnetic layer depth Curie isotherm Heat flow Crustal seismicity Flat subduction South America