oalib
Search Results: 1 - 10 of 78 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /78
Display every page Item
EFECTO DEL GRADIENTE ALTITUDINAL SOBRE ASPECTOS AUTOECOLóGICOS DE ESPELETIA PYCNOPHYLLA ssp. ANGELENSIS CUATREC. (ASTERACEAE) EN EL PáRAMO EL INFIERNILLO (NARI?O-COLOMBIA)
Benavides-Martínez,Iván F.; Burbano-Martínez,Diana L.; Urbano-Apráez,Sandra M.; Solarte-Cruz,María E.;
Actualidades Biológicas , 2007,
Abstract: some autoecological features of espeletia pycnophylla ssp. angelensis cuatrec. such as its demographic structure, population density, spatial pattern of dispersion, production of reproductive structures, adult morphometry and survivorship, were studied in an altitudinal gradient on a dry paramo of nari?o (colombia). hypothesis proposed by other authors about a linear effect caused by the elevation on these variables were completely rejected. the elevation induces an ecoclinal effect on population density, and this density correlates negatively with both production of reproductive structures and adult sizes. these results elucidate an unequivocal effect of density-dependence phenomena on population fitness. the intermediate zone of the altitudinal gradient exhibits a high population density, but on the other hand show reduced corporal adult sizes, minimal production of reproductive structures and the probability of juveniles reaching advanced ages is low. evidently, this intermediate elevation can have favorable ecological conditions for the seedling establishment, wich increments population densities at long term. we propose that other author's generalizations about the influence of elevation on the autoecology of these plants are limited, because the particular life and disturbance stories of paramos and the spatial, ecological and genetic isolating are explicative factors impossible to take away from the context. the demographic structure of the population fitted the logarithmic model, revealing its early regeneration state from the last fire event on 2003 and the similarity of the survivorship curves among every elevation, probed a high demographic stability.
Inferring possible population divergence in Espeletia pycnophylla (Asteraceae) through morphometric and paleogeographic approaches  [cached]
Felipe Benavides,Jorge Burbano,Diana Burbano,Rodrigo Prieto
Revista de Biología Tropical , 2010,
Abstract: The phenotypic structure within and between plant populations is generally influenced by their distribution patterns in space and time; therefore, the study of their divergence is a central issue for the understanding of their microevolutive processes. We boarded the hypothesis that three populations of Espeletia pycnophylla show phenotypic divergence as one of the possible implications of their geographic isolation in the Southern Colombian Andes. We used the Elliptic Fourier Descriptors (leaf shape) and traditional leaf morphometry (leaf size) of 347 leaves to measure inter and intra-population variation and a comparison between a paleogeographic reconstruction with an actual estimate of the distribution areas of E. pycnophylla in order to identify their main changes during the last 14 000 years. The three populations showed significant differences in leaf morphometry and a positive correlation between the matrices of morphometric and geographic dissimilarities, indicating that the inter-population divergence increases between further populations, so that the morphometric structure reflects their spatial distribution. The geographical and paleogeographical estimates evidenced a conspicuous process of reduction and fragmentation of the distribution area of E. pycnophylla since the Late-Glacial until the Holocene. We suggest that these results support possible scenarios of vicariance events, which allow us to approach the divergence of these populations in terms of their historic biogeographic relations. However, genetic analyses are still needed to support these results. Rev. Biol. Trop. 58 (4): 1261-1270. Epub 2010 December 01. La estructuración fenotípica entre y dentro de poblaciones vegetales responde generalmente a sus patrones de distribución espacio-temporales, por lo tanto, el estudio de su divergencia es un tema central dentro de sus procesos microevolutivos. En esta investigación abordamos la hipótesis que tres poblaciones de Espeletia pycnophylla presentan divergencia fenotípica como uno de los posibles efectos de su aislamiento geográfico en los Paramos del suroeste de Colombia. Utilizamos los Descriptores Elípticos de Fourier (forma foliar) de 117 hojas y algunas medidas morfológicas tradicionales (tama o foliar) como indicadores de la variación intra e inter-poblacional, además de una comparación entre una reconstrucción paleogeográfica con una estimación del área de distribución actual de la especie para identificar sus principales cambios durante los últimos 14 000 a os. Todas las poblaciones mostraron diferencias significativas y ademá
Inferring possible population divergence in Espeletia pycnophylla (Asteraceae) through morphometric and paleogeographic approaches
Benavides,Felipe; Burbano,Jorge; Burbano,Diana; Prieto,Rodrigo; Torres,Carlos;
Revista de Biología Tropical , 2010,
Abstract: the phenotypic structure within and between plant populations is generally influenced by their distribution patterns in space and time; therefore, the study of their divergence is a central issue for the understanding of their microevolutive processes. we boarded the hypothesis that three populations of espeletia pycnophylla show phenotypic divergence as one of the possible implications of their geographic isolation in the southern colombian andes. we used the elliptic fourier descriptors (leaf shape) and traditional leaf morphometry (leaf size) of 347 leaves to measure inter and intra-population variation and a comparison between a paleogeographic reconstruction with an actual estimate of the distribution areas of e. pycnophylla in order to identify their main changes during the last 14 000 years. the three populations showed significant differences in leaf morphometry and a positive correlation between the matrices of morphometric and geographic dissimilarities, indicating that the inter-population divergence increases between further populations, so that the morphometric structure reflects their spatial distribution. the geographical and paleogeographical estimates evidenced a conspicuous process of reduction and fragmentation of the distribution area of e. pycnophylla since the late-glacial until the holocene. we suggest that these results support possible scenarios of vicariance events, which allow us to approach the divergence of these populations in terms of their historic biogeographic relations. however, genetic analyses are still needed to support these results. rev. biol. trop. 58 (4): 1261-1270. epub 2010 december 01.
A nomenclator for the frailejones (Espeletiinae Cuatrec., Asteraceae)
Mauricio Diazgranados
PhytoKeys , 2012, DOI: 10.3897/phytokeys.16.3186
Abstract: The páramos and high Andean forests of the tropical Andes are largely dominated by frailejones (Espeletiinae Cuatrec., Asteraceae). These plants are ecologically and culturally essential for both ecosystems and local inhabitants. The frailejones have been studied for over two centuries, but the taxonomic knowledge is still sparse and incomplete. The inedited monograph by Cuatrecasas contains only ca. 70% of the species known today, and publications in the last decade disagree regarding the number of taxa within the group, with estimates ranging from 3 genera and 90 species to 8 genera and 154 species. Moreover the literature contains inexact information about their distribution. As part of a study of the phylogenetic and biogeographic relationships of the group, a thorough revision of the nomenclature was needed as a first step. Currently the subtribe has 8 recognized genera, 141 species, 17 subspecies, 22 varieties, 8 forms, 33 recognized hybrids, 142 synonyms and 5 invalid names, for a total of 368 names (autonyms not counted). The most current list of taxa is presented here, along with some notes and Spanish names. Tamananthus crinitus V.M.Badillo is not included within the subtribe. Various previous species or infraspecific taxa (i.e. Carramboa tachirensis (Aristeg.) Cuatrec., Espeletia algodonosa Aristeg., E. aurantia Aristeg., E. brassicoidea var. macroclada, E. brassicoidea var. pedunculata, E. garcibarrigae Cuatrec. and Espeletiopsis cristalinensis (Cuatrec.) Cuatrec.) are proposed or confirmed as hybrids. Two new records for Colombia are mentioned: Ruilopezia cardonae (Cuatrec.) Cuatrec., which is the first report of Ruilopezia for that country, and Espeletia steyermarkii Cuatrec. Observations regarding the frequency of hybrids in the subtribe are also given.
Estructura primaria del sistema radical de Coespeletia Cuatrec.
Luque Arias,Rebeca;
Interciencia , 2004,
Abstract: the morphology and primary root structure of the species coespeletia cuatrec. that grow in the mountains of piedras blancas and sierra nevada, mérida, venezuela, are shown. the species are coespeletia alba, c. lutesecens, c. moritziana, c. spicata and c. timotensis. the presence of common characters such as monostratified epidermis that is rapidly replaced by the exodermis, presence of secretory cavities associated to the endodermis and the secretory nature of endodermis, were detected. differential characters were detected as well, such as cortex structure, number of primary xylem arcs, and number of cavities occurring opposite the phloem.
Sand Waves Generation: A Numerical Investigation of the Infiernillo Channel in the Gulf of California  [PDF]
Yovani Monta?o Ley, Noel Carbajal
Open Journal of Marine Science (OJMS) , 2016, DOI: 10.4236/ojms.2016.63035
Abstract: The effect of the coastal geometry on sand bed forms generation has been investigated for a tidal dominated area. Different hypothetical geometries of coastal channels with flat bottoms and unlimited sediment availability were exposed to strong oscillatory tidal currents to simulate the interaction of hydrodynamics and the bedload sediment transport. The hypothetical geometries stand for the idealization of the principal geographic features of the Infiernillo Channel, a coastal area of the Gulf of California where sandbanks and sand waves have been observed. A depth integrated hydrodynamic-numerical model and a parameterized formula to estimate the bedload sediment transport were applied coupled with a sediment conservation equation to determine the sea bottom morphodynamics. Model predictions in the Infiernillo Channel were compared to available satellite imagery. This investigation demonstrates that a vertical integrated numerical model is able to reproduce the development of incipient sand waves that exist in the Infiernillo Channel. Incipient sandbanks and shoals were also simulated. Sand waves with wavelengths of about 200 m were calculated on the same locations where sand waves actually exist. A crucial finding of this research was to show that the geometry of a shallow water basin and the presence of tidal velocity gradients associated with abrupt changes in the coastline alignment were critical in determining the sand-bed pattern generation. We demonstrate that a vertical variation of tidal currents is not necessary to generate sand waves.
ACTIVIDAD ANTIBACTERIANA DE Diplostephium tolimense Cuatrec. (ASTERACEAE) FRENTE A Staphylococcus aureus ANTIBACTERIAL ACTIVITY OF Diplostephium tolimense Cuatrec. (ASTERACEAE) AGAINST Staphylococcus aures  [cached]
Liliana áVILA,Eduard BAQUERO,Amparo VI?A,Elizabeth MURILLO
Vitae , 2006,
Abstract: Se presenta el estudio de la actividad antibacteriana de la especie vegetal Diplostephium tolimense Cuatrec. (Asteraceae), colectada en el páramo del nevado del Tolima, la cual cuenta con pocos estudios químicos y farmacológicos, al igual que muchas otras especies de este ecosistema. A partir de un extracto etanólico crudo y mediante partición biodirigida se obtiene la fracción más simple de mayor actividad frente a Staphylococcus aureus (ATCC 25923). Paralelamente se realizan análisis fitoquímicos a las porciones de mayor bioactividad obtenidas durante todo el proceso. Se observa que la acción antibacteriana se incrementa al aumentar la simplicidad química del extracto y que terpenos y flavonoides parecen estar relacionados con la acción revelada. Se trata del primer reporte, hasta la fecha conocido, de actividad antibacteriana in vitro para D. tolimense. A study of antibacterial activity of the Diplostephium tolimense Cuatrec (Asteraceae) vegetal species, which was collected in the paramo of Tolima, is presented. This species, as many others of this ecosystem, has had few chemical and pharmacological studies. The simplest fraction with the largest activity against Staphylococcus aureus (ATCC 25923), is obtained starting from a raw ethanol extract and by means of bioassay guided partition. Parallelly, phytochemical analyses to the portions of greater bioactivity, obtained during the whole process, are carried out. It is observed that antibacterial action increases as the chemical simplicity increases and that the presence of terpenes and flavonoids seems to be related with this action. This is the first report, so far well-known, of in vitro antibacterial activity for D. tolimense.
Antimicrobial activity of bergenin from Endopleura uchi (Huber) Cuatrec
Silva, Saulo L. da;Oliveira, Viviane Guedes de;Yano, Tomomasa;Nunomura, Rita de Cássia Saraiva;
Acta Amazonica , 2009, DOI: 10.1590/S0044-59672009000100019
Abstract: endopleura uchi (huber) cuatrec. is an amazon species traditionally used as treatment for inflammations and female disorders. bergenin was isolated from ethyl acetate fraction of bark of e. uchi by using column chromatography over sephadex lh-20 and then silica gel 60 flash. its structure was identified on the basis of its nmr spectra. the antimicrobial activity of bergenin and fractions of methanol extract of e. uchi were evaluated against atcc microorganisms (escherichia coli, salmonella enteritidis, pseudomonas aeruginosa, enterococcus faecalis, staphylococcus aureus, candida albicans, c. guilliermondii, aspergillus flavus, a. nidulans). clinically isolated strains of all of these microorganisms, along with c. tropicalis, a. niger, shigella sonnei, serratia marcenses and klebsiella pneumoniae were also evaluated. the growth inhibition caused by bergenin, extracts and fractions of e. uchi against atcc microorganisms were similar to the inhibition to microorganisms clinically isolated. the ethyl acetate fraction and the isolate bergenin inhibit the growth of the yeasts c. albicans, c. tropicalis, and c. guilliermondii, but present lower activity against filamentous fungi aspergillus flavus, a. nidulans, a. niger, and did not inhibit the gram positive and gram negative bacteria. the activity of the ethyl acetate fraction and bergenin are in agreement wit its high concentration found in bark extract of e. uchi. moreover, the selective activity against three candida species helps to understand its traditional use against infections that affect women.
Caracterización de un entierro humano en la Quebrada de Los Corrales (El Infiernillo, Tucumán) Characterization Of A Human Burial In Quebrada De Los Corrales, El Infiernillo, Tucumán  [cached]
Nurit Oliszewski,C. Matías Gramajo Bühler,Eduardo P. Mauri,Gabriel E. Miguez
Intersecciones en Antropología , 2010,
Abstract: En la presente nota se dan a conocer las características generales del hallazgo de un entierro en la Quebrada de Los Corrales (El Infiernillo, Tucumán). Se trata de un entierro directo en cista de un único individuo adulto de sexo masculino. Una datación por AMS realizada sobre el mismo arrojó un fechado de ca. 1560 a os AP. Junto a los restos óseos humanos se registró la asociación de dos vasijas asignables a los estilos cerámicos Tafí y Candelaria. In this article the general characteristics of a burial site in the Quebrada de Los Corrales, El Infiernillo, Tucumán, are presented. This is a direct cist burial of an adult male. AMS radiocarbon dating established a date of ca. 1560 years BP. Two vases were recorded in association with the human remains, assignable to the Tafi and Candelaria ceramic styles.
Caracterización de un entierro humano en la Quebrada de Los Corrales (El Infiernillo, Tucumán)
Oliszewski,Nurit; Gramajo Bühler,C. Matías; Mauri,Eduardo P.; Miguez,Gabriel E.; Muntaner,Ana C.; Pantorrilla Rivas,Martín M.;
Intersecciones en antropolog?-a , 2010,
Abstract: in this article the general characteristics of a burial site in the quebrada de los corrales, el infiernillo, tucumán, are presented. this is a direct cist burial of an adult male. ams radiocarbon dating established a date of ca. 1560 years bp. two vases were recorded in association with the human remains, assignable to the tafi and candelaria ceramic styles.
Page 1 /78
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.