998 resultados para Peruvian Andes
Resumo:
Lycaenid caterpillars (Lepidoptera, Lycaenidae) eating flowers of Dalea pennellii var. chilensis (Fabaceae) in the northern Chilean Andes. The shrub Dalea pennellii var. chilensis (Fabaceae) is reported for the first time as a host plant for three Neotropical Polyommatini (Lepidoptera, Lycaenidae, Polyommatinae): Hemiargus ramon (Dognin, 1887), Leptotes trigemmatus (Butler, 1881) and Nabokovia faga (Dognin, 1895), based on two collections performed in the western slopes of the northern Chilean Andes in two consecutive summers. The relative abundance was always above 90% for N. faga while it was always less than 5% for H. ramon and L. trigemmatus. Furthermore, N. faga was not found on inflorescences of other native Fabaceae examined in the study site. This pattern suggests a close relationship between N. faga and D. pennellii var. chilensis, at least at a local scale.
Resumo:
The research performed a sustainability assessment of supply chains of the anchoveta (Engraulis ringens) in Peru. The corresponding fisheries lands 6.5 million t per year, of which <2% is rendered into products for direct human consumption (DHC) and 98% reduced into feed ingredients (fishmeal and fish oil, FMFO), for export. Several industries compete for the anchoveta resources, generating local and global impacts. The need for understanding these dynamics, towards sustainability-improving management and policy recommendations, determined the development of a sustainability assessment framework: 1) characterisation and modelling of the systems under study (with Life Cycle Assessment and other tools) including local aquaculture, 2) calculation of sustainability indicators (i.e. energy efficiency, nutritional value, socio-economic performances), and 3) sustainability comparison of supply chains; definition and comparison of alternative exploitation scenarios. Future exploitation scenarios were defined by combining an ecosystem and a material flow models: continuation of the status quo (Scenario 1), shift towards increased proportion of DHC production (Scenario 2), and radical reduction of the anchoveta harvest in order for other fish stocks to recover and be exploited for DHC (Scenario 3). Scenario 2 was identified as the most sustainable. Management and policy recommendations include improving of: controls for compliance with management measures, sanitary conditions for DHC, landing infrastructure for small- and medium-scale (SMS) fisheries; the development of a national refrigerated distribution chain; and the assignation of flexible tolerances for discards from different DHC processes.
Resumo:
Objetivo del artículo es reflexionar sobre el llamado «escándalo del Putumayo» estallado en la primera década del siglo XX, en la región objeto de litigio fronterizo entre Perú y Colombia. La denuncia en la prensa internacional de la explotación de los indígenas amazónicos hecha por la empresa «Peruvian Amazon Company», de la que el principal accionista fue el cauchero Julio C. Arana, presentó la región como un nuevo «Congo peruano» y provocó la intervención de Gran Bretaña, Perú, el Vaticano, Colombia y el propio Arana. A partir de repositorios documentales de la cancillería peruana, de los archivos de la Santa Sede, de la folletística y bibliografía publicada por las partes involucradas se plantea una reflexión sobre el escándalo, incidiendo en los argumentos sostenidos por las partes, en particular la peruanización de la región, defendida por Arana y el gobierno peruano.
Resumo:
The majority (60 %) of the soils in the Venezuelan Andes are Inceptisols, a large percentage of which are classified as Dystrustepts by the US Soil Taxonomy, Second Edition of 1999. Some of these soils were classified as Humitropepts (high organic - C-OC-soils) and Dystropepts by the Soil Taxonomy prior to 1999, but no equivalent large group was created for high-OC soils in the new Ustepts suborder. Dystrusepts developed on different materials, relief and vegetation. Their properties are closely related with the parent material. Soils developed on transported deposits or sediments have darker and thicker A horizons, a slightly acid reaction, greater CEC and OC contents than upland slope soils. Based on the previous classification into large groups (Humitropepts and Dystropepts) we found that: Humitropepts have a slightly less acid and higher values of CEC than Dystropepts. These properties or characteristics seem to be related to the fact that Humitropepts have a higher clay and OC content than the Dystropepts. Canonical discrimination analysis showed that the variables that discriminate the two great soil groups from each other are OC and silt. Data for Humitropepts are grouped around the OC vector (defining axis 3, principal component analysis), while Dystropepts are associated with the clay and sand vectors, with significant correlation. Given the importance of OC for soil properties, we propose the creation of a new large group named Humustepts for the order Inceptisol, suborder Ustepts.
Resumo:
El presente volumen, que corresponde a los dos primeros números del volumen 32 de ACTA GEOLOGICA HISPANICA, está dedicado a algunos de los aspectos geológicos más importantes de la zona de los Andes Centrales Argentino-Chilenos, y constituye una recopilación de trabajos de diferentes autores americanos y españoles.
Resumo:
A high-resolution U-Pb zircon geochronological study of plutonic units along the south Peruvian margin between 17 degrees and 18 degrees S allows the integration of the geochemical, geodynamic and tectonic evolution of this part of the Andean margin. This study focuses on the composite Jurassic-early Cretaceous Ilo Batholith that was emplaced along the southern Peruvian coast during two episodes of intrusive magmatism; a first period between 173 and 152 Ma (with a peak in magmatic activity between roughly 168 and 162 Ma) and a second period between 110 and 106 Ma. Emplacement of the Jurassic part of the composite Ilo Batholith shortly post-dated the accumulation of the volcanosedimentary succession it intruded (Chocolate formation), which allows to estimate a subsidence rate for this unit of similar to 3.5 km/Ma. The emplacement of the main peak of Jurassic plutonism of the Ilo Batholith was also closely coeval with widespread and repeated slumping (during deposition of the Cachios Formation) in the back-arc region, suggesting a common causal link between these phenomena, which is discussed in the context of an observed 100 km trenchward arc migration at similar to 175 Ma, and the relation with extensional tectonics that prevailed along the Central Andean margin during Pangaea break-up. (C) 2012 Elsevier B.V. All rights reserved.
Resumo:
Uno de los proyectos de gran envergadura de la Universidad de Los Andes (ULA) es la creación de la Biblioteca Digital de Tesis Electrónicas. Su consecución garantiza elevados niveles de interacción entre los actores internos y externos de la ULA a través de la consulta y publicación de la producción científica e intelectual de la Institución. En este artículo se presenta, en particular, la experiencia en la adaptación de la plataforma TEDE para la publicación de tesis electrónicas. La adaptación de la plataforma TEDE se llevó a cabo en tres etapas, a saber: a) Instalación, configuración y prueba de funcionalidad de la plataforma, b) Configuración y pruebas para el caso ULA, y c) Adaptación de la plataforma a la ULA. El resultado de esta adaptación fue una plataforma única que cumple con los requerimientos básicos establecidos para la publicación de tesis electrónicas en la ULA y que se ajusta perfectamente a cualquier institución académica de Venezuela. Muestra de esta experiencia ULA es su implantación en otras universidades nacionales como la Universidad del Zulia (LUZ), la Universidad Simón Bolívar (USB) y la Universidad Nacional Experimental de los Llanos Ezequiel Zamora (UNELLEZ).
Resumo:
The objective of this study was to characterize the Peruvian isolate of Metarhizium anisopliae var. acridum, CG 863, obtained from the grasshopper Schistocerca interrita, a crop pest in Peru. The characterization was done by comparing this isolate with two other ones of M. anisopliae var. acridum, from Brazil and Australia, and with an isolate of M. anisopliae var. anisopliae. The three M. anisopliae var. acridum isolates had similar growth profiles in agar plates at 25°C and 37°C, and similar RAPD patterns according to the analysis of three primers. However, regarding these parameters and conidial size, these isolates were very distinct when compared to M. anisopliae var. anisopliae isolate. Bioassays indicated that the Peruvian isolate is as pathogenic as the Brazilian isolate against nymphs of Rhammatocerus schistocercoides.
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We report new high-precision U/Pb ages and geochemical data from the Chalten Plutonic Complex to better understand the link between magmatism and tectonics in Southern Patagonia. This small intrusion located in the back-arc region east of the Patagonian Batholith provides important insights on the role of arc migration and subduction erosion. The Chalten Plutonic Complex consists of a suite of calc-alkaline gabbroic to granitic rocks, which were emplaced over 530 kyr between 16.90 +/- 0.05 Ma and 16.37 +/- 0.02 Ma. A synthesis of age and geochemical data from other intrusions in Patagonia reveals (a) striking similarities between the Chalten Plutonic Complex and the Neogene intrusions of the batholith and differences to other back-arc intrusions such as Torres del Paine (b) a distinct E-W trend of calc-alkaline magmatic activity between 20 and 17 Ma. We propose that this trend reflects the eastward migration of the magmatic arc, and the consistent age pattern between the subduction segments north and south of the Chile triple junction suggests a causal relation with a period of fast subduction of the Farallon-Nazca plate during the Early Miocene. Previously proposed flat slab models are not consistent with the present location and morphology of the Southern Patagonian Batholith. We advocate, alternatively, that migration of the magmatic arc is caused by subduction erosion due to the increasing subduction velocities during the Early Miocene.
Resumo:
The results of a coupled, in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb study on zircon and geochemical characterization of the Eastern Cordilleran intrusives of Peru reveal 1.15 Ga of intermittent magmatism along central Western Amazonia, the Earth's oldest active open continental margin. The eastern Peruvian batholiths are volumetrically dominated by plutonism related to the assembly and breakup of Pangea during the Paleozoic-Mesozoic transition. A Carboniferous-Permian (340-285 Ma) continental arc is identified along the regional orogenic strike from the Ecuadorian border (6 degrees S) to the inferred inboard extension of the Arequipa-Antofalla terrane in southern Peru (14 degrees S). Widespread crustal extension and thinning, which affected western Gondwana throughout the Permian and Triassic resulted in the intrusion of the late- to post-tectonic La Merced-San Ramon-type anatectites dated between 275 and 220 Ma, while the emplacement of the southern Cordillera de Carabaya peraluminous granitoids in the Late Triassic to Early Jurassic (220-190 Ma) represents, temporally and regionally, a separate tectonomagmatic event likely related to resuturing of the Arequipa-Antofalla block. Volcano-plutonic complexes and stocks associated with the onset of the present Andean cycle define a compositionally bimodal alkaline suite and cluster between 180 and 170 Ma. A volumetrically minor intrusive pulse of Oligocene age (ca. 30 Ma) is detected near the southwestern Cordilleran border with the Altiplano. Both post-Gondwanide (30-170 Ma), and Precambrian plutonism (691-1123 Ma) are restricted to isolated occurrences spatially comprising less than 15% of the Eastern Cordillera intrusives. Only one remnant of a Late Ordovician intrusive belt is recognized in the Cuzco batholith (446.5 +/- 9.7 Ma) indicating that the Famatinian arc system previously identified in Peru along the north-central Eastern Cordillera and the coastal Arequipa-Antofalla terrane also existed inboard of this parautochthonous crustal fragment. Hitherto unknown occurrences of late Mesoproterozoic and middle Neoproterozoic granitoids from the south-central cordilleran segment define magmatic events at 691 +/- 13 Ma, 751 +/- 8 Ma, 985 +/- 14 Ma, and 1071-1123 +/- 23 Ma that are broadly coeval with the Braziliano and Grenville-Sunsas orogenies, respectively. Our data suggest the existence of a continuous orogenic belt in excess of 3500 km along Western Amazonia during the formation of Rodinia, its ``early'' fragmentation prior to 690 Ma, and support a model of reaccretion of the Paracas-Arequipa-Antofalla terrane to western Gondwana in the Early Ordovician with subsequent detachment of the Paracas segment in form of the Mexican Oaxaquia microcontinent in Middle Ordovician. A tectonomagmatic model involving slab detachment, followed by underplating of cratonic margin by asthenospheric mantle is proposed for the genesis of the volumetrically dominant Late Paleozoic to early Mesozoic Peruvian Cordilleran batholiths.
Resumo:
Bajo el título genérico de"Geología de los Andes Centrales Meridionales: El Noroeste Argentino" se recopilan un conjunto de trabajos realizados en los últimos años en sectores del Noroeste A rgentino. Las investigaciones realizadas se localizan en la región andina de la provincia de Salta y territorios adyacentes. Este volumen monográfico reúne trabajos que constituyen el esfuerzo conjunto de veinticinco autores de diferentes países, europeos y suramericanos, trabajando en proyectos de colaboración internacional .