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Search Results: 1 - 10 of 122609 matches for " ANA I MEDINA "
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Composición y abundancia de Chironomidae (Diptera) en un río serrano de zona semiárida (San Luis, Argentina)
Medina,Ana I.; Paggi,Analía C.;
Revista de la Sociedad Entomol?3gica Argentina , 2004,
Abstract: species abundance of chironomidae (diptera) has often been excluded from studies of benthic river communities because of the difficulties associated with the identification of larvae. the composition and seasonal abundance of the chironomid larvae assemblage in the upper reaches of the grande river were studied. twenty-four genera belonging to the subfamilies chironominae, tanypodinae and orthocladiinae were collected. chironominae showed the most generic richness (11 taxa), followed by tanypodinae (8) and, orthocladiinae (5). likewise, tanytarsini showed the highest density, followed by pentaneurini and orthocladiini. the faunistic distribution of chironomidae found in the grande river showed a considerable number of taxa in common with the amazonic fauna, especifically regarding the subfamilies richness and generic composition. new ecological characteristics related to the habitat of some chironomidae genera were observed.
Composición y abundancia de Chironomidae (Diptera) en un río serrano de zona semiárida (San Luis, Argentina) Composition and abundance of Chironomidae (Diptera) in a semiarid stream (San Luis, Argentina)
Ana I. Medina,Analía C. Paggi
Revista de la Sociedad Entomol?3gica Argentina , 2004,
Abstract: En numerosas investigaciones acerca de las comunidades bentónicas de ambientes lóticos ha quedado excluído el estudio de la diversidad y abundancia de la familia Chironomidae (Diptera), debido a las dificultades que presenta la taxonomía de los estados inmaduros. En este trabajo se estudió la composición y abundancia larval de la familia Chironomidae en el tramo no-regulado del río Grande. Se identificaron 24 géneros correspondientes a tres subfamilias; Chironominae, Tanypodinae y Orthocladiinae. Chironominae fue la subfamilia con mayor riqueza genérica (11), siguiéndole Tanypodinae (8) y por último Orthocladiinae con sólo cinco. En la misma secuencia la tribu Tanytarsini fue la más abundante, seguidas de Pentaneurini y Orthocladiini. La distribución faunística de Chironomidae hallada en el río Grande mostró semejanzas con la fauna amazónica, en cuanto a la riqueza de cada subfamilia y a su composición genérica. Se describen características ecológicas hasta ahora no descriptas con respecto al hábitat que ocupan algunos géneros de Chironomidae. Species abundance of Chironomidae (Diptera) has often been excluded from studies of benthic river communities because of the difficulties associated with the identification of larvae. The composition and seasonal abundance of the chironomid larvae assemblage in the upper reaches of the Grande river were studied. Twenty-four genera belonging to the subfamilies Chironominae, Tanypodinae and Orthocladiinae were collected. Chironominae showed the most generic richness (11 taxa), followed by Tanypodinae (8) and, Orthocladiinae (5). Likewise, Tanytarsini showed the highest density, followed by Pentaneurini and Orthocladiini. The faunistic distribution of Chironomidae found in the Grande river showed a considerable number of taxa in common with the Amazonic fauna, especifically regarding the subfamilies richness and generic composition. New ecological characteristics related to the habitat of some Chironomidae genera were observed.
Patrones de actividad forrajera y tama o de nido de Acromyrmex lobicornis (Hymenoptera: Formicidae) en una zona urbana de San Luis, Argentina Foraging activity patterns and nest size of Acromyrmex lobicornis (Hymenoptera: Formicidae) in an urban zone of San Luis, Argentina
Laura E. Jofré,Ana I. Medina
Revista de la Sociedad Entomol?3gica Argentina , 2012,
Abstract: Diversos factores pueden influir sobre la actividad de forrajeo de las hormigas cortadoras de hojas. Sin embargo, los factores climáticos, especialmente la temperatura, pueden ser considerados los más importantes en las regiones templadas. Se midió la actividad de forrajeo y el tama o del nido en cuatro colonias de Acromyrmex lobicornis Emery en la localidad de Juana Koslay, San Luis. La actividad forrajera se determinó a partir del número de hormigas que ingresan al nido cargadas con fragmentos vegetales por unidad de tiempo, a lo largo de un a o. Se midió la temperatura del aire y el suelo en cada oportunidad. Para estimar el tama o del nido, se midió el área de forrajeo, el diámetro del túmulo y el número de obreras en cada colonia. Se encontraron asociaciones entre la actividad de forrajeo y las temperaturas del aire y del suelo en todos los meses del a o, a excepción de febrero, julio y diciembre. Esta asociación fue positiva en los meses de octubre, mayo, junio, agosto y setiembre; pero negativa en los meses de noviembre, enero, marzo y abril. Las colonias mostraron actividad diurna en invierno y nocturna en verano. La temperatura y el tama o del nido son factores que influyen sobre la actividad de forrajeo de A. lobicornis. Many factors can affect the foraging activity of leaf-cutting ants. However, climatic factors, especially temperature, could be considered the most important in temperate regions. In this work, we measured foraging activity and nest size in four colonies of Acromyrmex lobicornis Emery located in Juana Koslay, San Luis. Foraging activity was determined by the number of ants carrying plant fragments that entered the nest per unit time during a year. In each opportunity air and soil temperature were measured. To estimate nest size we used foraging area, mound diameter and number of workers in each colony Foraging activity and air and soil temperature correlated in every month of the year except February, July and December. However, the correlation was positive during October, May, June, August and September, and negative in November, January, March and April. The nests showed activity all the year, but diurnal in winter and nocturnal in summer. The temperature and the nest size are factors that influence the foraging activity of A. lobicornis.
Distribución de Chironomidae (Diptera) en dos sistemas fluviales ritrónicos (Andino-serrano) de Argentina
Medina,Ana I.; Scheibler,Erica E.; Paggi,Analía C.;
Revista de la Sociedad Entomol?3gica Argentina , 2008,
Abstract: the first records are presented concerning the current status of faunal composition for chironomidae larvae (diptera) from two river systems: mendoza river (mendoza) and grande river (san luis), at the same latitude in the cuyo region. distribution patterns were analyzed and larvae assemblage compared with similar rhitronic river systems. in the case of mendoza river, the subfamily orthocladiinae exhibited the highest generic richness (5) followed by podonominae with three genera; whereas the other subfamilies found, composed of: chironominae (2), diamesinae (2) and tanypodinae (1), exhibited the lowest generic densities. in the grande river, the distribution pattern of subfamilies always showed the highest generic density for chironominae (11), followed by tanypodinae (8) and finally orthocladiinae (5). differences between these two environments were found among taxonomic groups in generic richness and relative abundance for the neotropical region. the faunal composition found in the mendoza river was made up of patagonian elements and the grande river was dominated by brasilic elements.
Exposure to creosote bush phenolic resin causes avoidance in the leaf-cutting ant Acromyrmex lobicornis (Formicidae: Attini) La exposición a la resina fenólica de jarilla causa deterrencia en la hormiga cortadora de hojas Acromyrmex lobicornis (Formicidae: Attini)
ANA I MEDINA,ANTONIO M MANGIONE,MATíAS GARCíA
Revista chilena de historia natural , 2012,
Abstract: We focused our study on the effects of Larrea cuneifolia phenolic resin on leaf-cutting ants from two populations (Sierra de las Quijadas National Park and San Roque) of Acromyrmex lobicornis in San Luis, Argentina. We conducted two bioassays of food choice (field and laboratory) to compare the effects of phenolic resin on ant workers from these two populations. Results of the field experiment indicated that there were no differences in preference for either leaves treated with resin or untreated leaves among colonies from both localities. However, results of the laboratory experiments with individual ants indicated a significant effect of population and treatment on the time spent in different treatments. While leaf-cutting individual workers from Quijadas preferred the phenolic resin, workers from San Roque avoided it. These results evidence that ants respond according to time of exposure to chemicals from plants (presence or absence) and that the effects of resin among a population can be observed and measured on individual ant workers, even in the absence of fungus garden influences in the nest. Este estudio se ha centrado en los efectos que produce la resina fenólica de Larrea cuneifolia sobre dos poblaciones distintas (Parque Nacional de Sierra de las Quijadas y la localidad de San Roque) de Acromyrmex lobicornis en San Luis, Argentina. Se disenaron dos tipos de bioensayos (a campo y en laboratorio) para comparar los efectos de la resina fenólica sobre las hormigas obreras de estas dos poblaciones. Los resultados de los experimentos de elección de la oferta alimentaria en el campo, indicaron que no hubo ninguna diferencia de preferencia entre las colonias, ni por las hojas tratadas con resina ni por las hojas sin tratar para ambas localidades. Sin embargo, los resultados de los experimentos de laboratorio con las hormigas obreras individualmente indicaron efectos significativos entre las poblaciones y entre los tratamientos. Mientras que las hormigas obreras de Quijadas prefirieron la resina fenólica, las obreras de San Roque la rechazaron. Estos resultados evidencian que las hormigas responden de acuerdo al tiempo de exposición a los productos naturales de las plantas (presencia y ausencia) y que los efectos de la resina entre poblaciones, puede ser observada y medida en las hormigas obreras aun en ausencia de la influencia del jardín de hongos de la colonia.
Distribución de Chironomidae (Diptera) en dos sistemas fluviales ritrónicos (Andino-serrano) de Argentina Chironomidae (Diptera) distribution in two fluvial rhitronic systems (Andean and hilly streams), Argentina
Ana I. Medina,Erica E. Scheibler,Analía C. Paggi
Revista de la Sociedad Entomol?3gica Argentina , 2008,
Abstract: Se presentan los primeros registros sobre el estado actual de la composición faunística de larvas de la familia Chironomidae (Diptera) en dos sistemas fluviales: río Mendoza (Mendoza) y río Grande (San Luis), a la misma latitud en una zona cuyana. Se analizaron los patrones de distribución y se comparó su taxocenosis con sistemas fluviales similares de tipo ritrónicas. En el caso del río Mendoza la subfamilia Orthocladiinae presentó la mayor riqueza genérica (5), siguiéndole Podonominae con tres géneros; mientras que el resto de las subfamilias halladas exhibieron las densidades genéricas más bajas, éstas compuestas por: Chironominae (2), Diamesinae (2) y Tanypodinae (1). En el río Grande, el patrón de distribución de las subfamilias mostró que la riqueza genérica máxima la obtuvo siempre Chironominae (11), le siguió Tanypodinae (8) y por último Orthocladiinae (5). Se encontraron diferencias tanto entre los grupos taxanómico y la riqueza genérica como en la abundancia relativa de las subfamilias para la región Neotropical. En cuanto a la composición faunística, ambos ríos muestran una marcada diferencia, el río Mendoza está predominantemente constituido por elementos patagónicos, en cambio la fauna encontrada en el río Grande está constituida por elementos brasílicos. The first records are presented concerning the current status of faunal composition for Chironomidae larvae (Diptera) from two river systems: Mendoza River (Mendoza) and Grande River (San Luis), at the same latitude in the Cuyo region. Distribution patterns were analyzed and larvae assemblage compared with similar rhitronic river systems. In the case of Mendoza River, the subfamily Orthocladiinae exhibited the highest generic richness (5) followed by Podonominae with three genera; whereas the other subfamilies found, composed of: Chironominae (2), Diamesinae (2) and Tanypodinae (1), exhibited the lowest generic densities. In the Grande River, the distribution pattern of subfamilies always showed the highest generic density for Chironominae (11), followed by Tanypodinae (8) and finally Orthocladiinae (5). Differences between these two environments were found among taxonomic groups in generic richness and relative abundance for the Neotropical region. The faunal composition found in the Mendoza River was made up of Patagonian elements and the Grande River was dominated by brasilic elements.
Gravitational and magnetic field variations synergize to cause subtle variations in the global transcriptional state of Arabidopsis in vitro callus cultures
Ana I Manzano, Jack JWA van Loon, Peter CM Christianen, Juana M Gonzalez-Rubio, F Javier Medina, Raul Herranz
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-105
Abstract: Using diamagnetic levitation, we exposed Arabidopsis thaliana in vitro callus cultures to five environments with different levels of effective gravity and magnetic field strengths. The environments included levitation, i.e. simulated μg* (close to 0 g* at B = 10.1 T), intermediate g* (0.1 g* at B = 14.7 T) and enhanced gravity levels (1.9 g* at B = 14.7 T and 2 g* at B = 10.1 T) plus an internal 1 g* control (B = 16.5 T). The asterisk denotes the presence of the background magnetic field, as opposed to the effective gravity environments in the absence of an applied magnetic field, created using a Random Position Machine (simulated μg) and a Large Diameter Centrifuge (2 g).Microarray analysis indicates that changes in the overall gene expression of cultured cells exposed to these unusual environments barely reach significance using an FDR algorithm. However, it was found that gravitational and magnetic fields produce synergistic variations in the steady state of the transcriptional profile of plants. Transcriptomic results confirm that high gradient magnetic fields (i.e. to create μg* and 2 g* conditions) have a significant effect, mainly on structural, abiotic stress genes and secondary metabolism genes, but these subtle gravitational effects are only observable using clustering methodologies.A detailed microarray dataset analysis, based on clustering of similarly expressed genes (GEDI software), can detect underlying global-scale responses, which cannot be detected by means of individual gene expression techniques using raw or corrected p values (FDR). A subtle, but consistent, genome-scale response to hypogravity environments was found, which was opposite to the response in a hypergravity environment.Since the beginning of life on Earth, organisms have lived under the influence of the Earth's physical parameters including its almost constant gravitational and magnetic fields. Therefore, evolution has had to provide a number of different solutions to meet the mecha
Estructura financiera de las empresas del clúster servicios médicos y odontológicos del Valle de Aburrá en ambientes cambiantes
Medina O.,Ana Milena;
Perfil de Coyuntura Económica , 2011,
Abstract: the aim of this study is to characterize the financial structure of the large and medium companies located at aburrá valley, belonging to the medical and dental services cluster. it wants to determine whether the behavior of this structure coincides with the position of pecking older theory (myer, 1984) and also, if it has variations during the economic recession period. the results suggest that the large company's financing decisions can be explained from the studied theory, with doesn't find a support in the case of medium companies that changes its financing structure during the economic crisis period, in which intensifies the use of short-term liabilities.
Representaciones del Cáncer en Estudiantes de Medicina: Implicaciones para la Práctica y la Ense?anza
Medina,Ana María;
Revista de Salud Pública , 2007, DOI: 10.1590/S0124-00642007000300005
Abstract: objective this study was aimed at reconstructing social representations regarding cancer formed by a group of health personnel (medical students) as part of a long-term study and how such representations affect relationships with patients and family members and their medical practice. methods the investigation integrated qualitative methods from social psychology and anthropology in medical education. four focal groups formed by medical students were applied throughout 2003 and 2004 for developing this phase. results for first semester medical students cancer was seen as being an entity independent of the person being afflicted by it, acquiring anthropomorphic or zoomorphic qualities, associated with a loss of limits and control. cancer patients were represented as being people without a future who would lose their social and affective links. discussion social representations must become changed in our immediate setting, leading to new ways of relating to cancer patients in medical services.
Roberto Suárez et al. Las rickettsias como agentes etiológicos de entidades febriles no diagnosticadas en Colombia
Medina Ana María
Maguaré , 2009,
Abstract: Rese a
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