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Search Results: 1 - 10 of 233340 matches for " MARCO; ALVIAL C "
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Consecuencias de la tala maderera colonial en los bosques de alerce de Chiloé, sur de Chile (Siglos XVI-XIX)
TORREJóN G,FERNANDO; CISTERNAS V,MARCO; ALVIAL C,INGRID; TORRES R,LAURA;
Magallania (Punta Arenas) , 2011, DOI: 10.4067/S0718-22442011000200006
Abstract: during the spanish settlement processes the wood from the alerce tree was the main economical resource of chiloé (southern chile), generating an important commercial activity in the region. the development of the alerce timber and trading was studied based on historical-documentary analysis including data from the 16th to 19th century. special attention on the environmental effect was assessed based on the original alerce forest conditions. findings allow concluding that the colonial alerce removal it would have caused only a minor disturbance to the original forest, and it would have taken place within the most accessible alerzales (alerce patches) only, contrary to the situation observed at the beginning of the republic period when an enormous alerce exploitation was experimented. therefore, it has been proved that the disappearance and extinction of alerzalesin chiloé, during the colonial domain, did not occur.
Consecuencias de la tala maderera colonial en los bosques de alerce de Chiloé, sur de Chile (Siglos XVI-XIX) Colonial timber felling consequences of the alerce forests in Chiloé, southern Chile (18TH and 19TH centuries)
FERNANDO TORREJóN G,MARCO CISTERNAS V,INGRID ALVIAL C,LAURA TORRES R
Magallania , 2011,
Abstract: Durante el proceso de colonización espa ola la madera de alerce se transformó en el principal recurso económico de Chiloé, generándose una importante actividad mercantil sustentada en la tala de dicha especie arbórea. Mediante un análisis histórico documental, que abarca desde el siglo XVI al XIX, se examinó la evolución de la tala y del comercio maderero local, evaluándose sus efectos ambientales sobre la cobertura boscosa original del territorio. Los resultados obtenidos permiten constatar que la tala colonial del alerce habría generado sólo una moderada alteración de los alerzales más accesibles, en comparación a lo ocurrido en los inicios de la República tras la notoria intensificación de la explotación maderera. En consecuencia se descarta la tradicional idea de la desaparición o extinción de alerzales en Chiloé durante el dominio colonial. During the Spanish settlement processes the wood from the Alerce tree was the main economical resource of Chiloé (Southern Chile), generating an important commercial activity in the region. The development of the Alerce timber and trading was studied based on historical-documentary analysis including data from the 16th to 19th century. Special attention on the environmental effect was assessed based on the original Alerce forest conditions. Findings allow concluding that the colonial Alerce removal it would have caused only a minor disturbance to the original forest, and it would have taken place within the most accessible Alerzales (Alerce patches) only, contrary to the situation observed at the beginning of the republic period when an enormous Alerce exploitation was experimented. Therefore, it has been proved that the disappearance and extinction of Alerzalesin Chiloé, during the colonial domain, did not occur.
Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile L’analyse des macroinvertébrés benthiques et indices biotiques pour évaluer la qualité de l’eau dans les rivières touchées par les activités minières dans le nord du Chili
Alvial I.E.,Tapia D.H.,Castro M.J.,Duran B.C.
Knowledge and Management of Aquatic Ecosystems , 2013, DOI: 10.1051/kmae/2012027
Abstract: Catchments in the semiarid regions are especially susceptible to environmental perturbation associated with water scarcity, hydrological variations and overuse by anthropogenic activities. Using multivariate analysis to relate environmental and biological data, and diversity and biotic indices (ChBMWP, ChIBF), we analyzed the macroinvertebrate composition of 12 rivers of the semiarid region of northern Chile. A non-metric multidimensional scaling for macroinvertebrate taxa and a principal component analysis for environmental variables strongly separated upstream sites (e.g. Vacas Heladas and Malo Rivers), which presented low pH and high dissolved metal concentrations, from other sites. Effectively, CCA showed that metals and low pH, associated with the altitudinal gradient, determined the distributional patterns of macroinvertebrates in the Elqui catchment. The causes of these particular conditions could be related to geological processes and human impact. The biotic indices applied to the sampling sites corroborated and reflected these characteristics, with La Laguna and Turbio Rivers showing a diverse macroinvertebrate community and moderate to good water quality, and the Claro River showing favorable conditions for the development of aquatic biota, indicating its better quality relative to other stations. To the middle and low part of the basin, a change in the composition of the community was observed, with species that suggest an impact by an increase in organic matter, due to agricultural activities and urban settlements concentrated in this area. Our results suggest that macroinvertebrate taxa in northern Chile may be exceptional species, adapted to unfavorable geochemical conditions, and emphasize the need for protection of the semiarid basins of the region. Les bassins versants des régions semi-arides sont particulièrement sensibles aux perturbations de l’environnement associées à la rareté de l’eau, aux variations hydrologiques et à la surexploitation par les activités anthropiques. Utilisant une analyse multivariée pour relier les données environnementales et biologiques, la diversité et des indices biotiques (ChBMWP, ChIBF), nous avons analysé la composition des macroinvertébrés des 12 rivières de la région semi-aride du nord du Chili. Une mise à l’échelle multidimensionnelle non métrique pour des taxons de macroinvertébrés et une analyse en composantes principales des variables environnementales, séparent fortement les sites amont (par exemple Vacas Heladas et rivières Malo), qui présentent un pH faible et des concentrations élevées de métau
Non-Gaussianity of the topological charge distribution in $\mathrm{SU}(3)$ Yang-Mills theory
Marco Cè
Physics , 2015,
Abstract: In Yang-Mills theory, the cumulants of the na\"ive lattice discretization of the topological charge evolved with the Yang-Mills gradient flow coincide, in the continuum limit, with those of the universal definition. We sketch in these proceedings the main points of the proof. By implementing the gradient-flow definition in numerical simulations, we report the results of a precise computation of the second and the fourth cumulant of the $\mathrm{SU}(3)$ Yang-Mills theory topological charge distribution, in order to measure the deviation from Gaussianity. A range of high-statistics Monte Carlo simulations with different lattice volumes and spacings is used to extrapolate the results to the continuum limit with confidence by keeping finite-volume effects negligible with respect to the statistical errors. Our best result for the topological susceptibility is $t_0^2\chi=6.67(7)\times 10^{-4}$, while for the ratio between the fourth and the second cumulant we obtain $R=0.233(45)$.
Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile
INGRID E ALVIAL,FABIOLA J CRUCES,ALBERTO E ARANEDA,GROSJEAN
Revista chilena de historia natural , 2008,
Abstract: En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensue o y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibba In this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensue o and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola and Planothidium lanceolatum. In the assemblages from lakes Galletué, Icalma and Laja planktonic diatoms were more abundant, which are common in alkaline and mesotrophic waters, e.g., Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera and Rhopalodia gibba
Color superconductivity, BPS Zk strings and monopole confinement in N = 2 and N = 4 super Yang-Mills theories
Kneipp, Marco A. C.;
Brazilian Journal of Physics , 2004, DOI: 10.1590/S0103-97332004000700009
Abstract: we review some recent developments on bps string solutions and monopole confinement in the higgs (or color) superconducting phase of = 2 and = 4 super yang-mills theories. in particular, the monopole magnetic fluxes are shown to be always integer linear combinations of string fluxes. moreover, a bound for the threshold length of the string breaking is obtained. when the gauge group su(n) is broken to zn, the bps string tension satisfies the casimir scaling law. furthermore, in the su(3) case the string solutions are such that they allow the formation of a confining system with three monopoles.
Comportamento excêntrico do efeito tuning em sísmica 4D
Schinelli, Marco C.;
Revista Brasileira de Geofísica , 2002, DOI: 10.1590/S0102-261X2002000200002
Abstract: the feasibility analysis of seismic monitoring of fluids flow in reservoirs, through consecutive seismic acquisition (known as 4d or time-lapse seismic), should not involve just the the laboratorial evaluation of modifications on physical response caused by the fluids substitution with the consequent variation of the elastic parameters, but mainly a previous phase of seismic modeling, whose importance is among others, to quantify the impact of the tuning effect that can subvert the expected amplitude variations after the time-lapse. in this sense such effect needs to be carefully investigated because, due to fluids substitution at the reservoirs level, the tuning variation can introduce a very important factor of influence on the seismic amplitudes, what can makes unfeasible the interpretation of the seismic4d.
Teoría de la escalera térmica
Macchiavello C,Marco Aurelio;
Revista chilena de infectología , 2009, DOI: 10.4067/S0716-10182009000500015
Abstract: in this article we raise the possibility of a potential relationship between body temperature of different spe-cies of animáis and the avian flu. we hypothesize that the different valúes of body temperature could act as an enabling mechanism for influenza virus infection through an adaptative mechanism of the virions in the species susceptible to infection, including human beings.
BPS Z(N) String Tensions, Sine Law and Casimir Scaling and Integrable Field Theories
Kneipp, Marco A. C.
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.76.125010
Abstract: We consider a Yang-Mills-Higgs theory with spontaneous symmetry breaking of the gauge group G -> U(1)^r -> C(G), with C(G) being the center of G. We study two vacua solutions of the theory which produce this symmetry breaking. We show that for one of these vacua, the theory in the Coulomb phase has the mass spectrum of particles and monopoles which is exactly the same as the mass spectrum of particles and solitons of two dimensional affine Toda field theory. That result holds also for N=4 Super Yang-Mills theories. On the other hand, in the Higgs phase, we show that for each of the two vacua the ratio of the tensions of the BPS Z(N) strings satisfy either the Casimir scaling or the sine law scaling for G=SU(N). These results are extended to other gauge groups: for the Casimir scaling, the ratios of the tensions are equal to the ratios of the quadratic Casimir constant of specific representations; for the sine law scaling, the tensions are proportional to the components of the left Perron-Frobenius eigenvector of Cartan matrix and the ratios of tensions are equal to the ratios of the soliton masses of affine Toda field theories.
Teoría de la escalera térmica Thermic stairways theory
Marco Aurelio Macchiavello C
Revista chilena de infectología , 2009,
Abstract: En el presente artículo se plantea una posible relación entre la temperatura corporal de diferentes especies animales y la presentación de la Gripe aviar. Se postula que los diferentes valores de temperatura corporal podrían actuar como un mecanismo favorecedor de las infecciones por virus Influenza, mediante un mecanismo de tipo ad-aptativo de los viriones en las diversas especies animales susceptibles a la infección, incluyendo al humano. In this article we raise the possibility of a potential relationship between body temperature of different spe-cies of animáis and the Avian Flu. We hypothesize that the different valúes of body temperature could act as an enabling mechanism for Influenza virus infection through an adaptative mechanism of the virions in the species susceptible to infection, including human beings.
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