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Search Results: 1 - 10 of 186260 matches for " MARCELO E KUN "
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Infestación de Megastigmus aculeatus (Hymenoptera: Chalcidoidea) en las semillas de rosas exóticas invasoras de comunidades naturales de la Patagonia andina de Argentina
LEDIUK,KAREN D; DAMASCOS,MARíA A; KUN,MARCELO E;
Revista chilena de historia natural , 2012, DOI: 10.4067/S0716-078X2012000100012
Abstract: megastigmus aculeatus swederus (hymenoptera: chalcidoidea) infest rosa species seeds both at the origin and invasion areas. the wasp larvae develop by consuming the entire seed. the m. aculeatus infestation was analyzed at different rosa canina l. and rosa rubiginosa l. populations and at isolated plants of rosa multiflora thunb. at norwestern patagonian natural areas of argentina. in r. rubiginosa, the most abundant species, we studied the wasp infestation prevalence and success and the possible infestation effect on fruit size. in this paper we registered the first records of r. canina and r. rubiginosa as host plants for m. aculeatus in wild areas of argentina and we verified the absence of the wasp in r. multiflora fruits. in r. canina the percentage of infected fruits by m. aculeatus was low (0-1 % per site) not being probably a conditioning factor of its actual reduced spread. in r. rubiginosa, the percentage was high (31-75 % of infested fruits per sites), but only the 2-8 % of achenes were infected. considering the analyzed sites, the distribution of m. aculeatus infestation at regional level in rose studied species was reduced. the fruit size was not affected by the insect infestation. the results of this work show a low actual impact of m. aculeatus in the control of rose invasion at andean region of argentina. however, since m. aculeatus populations could be affect by the temperature, a change of this variable could increase the seeds infestation prevalence in the medium and long term.
Infestación de Megastigmus aculeatus (Hymenoptera: Chalcidoidea) en las semillas de rosas exóticas invasoras de comunidades naturales de la Patagonia andina de Argentina Megastigmus aculeatus infestation on seeds of exotic roses invading wild communities of Andean Patagonia from Argentina
KAREN D LEDIUK,MARíA A DAMASCOS,MARCELO E KUN
Revista chilena de historia natural , 2012,
Abstract: Megastigmus aculeatus Swederus (Hymenoptera: Chalcidoidea) infesta las semillas de especies de Rosa tanto en las áreas de origen como en las de invasión. La larva de la avispa se desarrolla consumiendo la totalidad de la semilla. Se analizó la infestación de M. aculeatus en diferentes poblaciones de Rosa rubiginosa L. y Rosa canina L. y en plantas aisladas de Rosa multiflora Thunb. en áreas naturales del Noroeste de la Patagonia, Argentina. En R. rubiginosa, la especie más abundante, estudiamos la prevalencia y éxito de infestación por la avispa y el posible efecto sobre el tama o del fruto. En este trabajo se presentan los primeros registros de R. rubiginosa y R. canina como especies hospedadoras de M. aculeatus en Argentina y se verifica su ausencia en las semillas de R. multiflora. En R. canina, el porcentaje de frutos infestados por M. aculeatus fue bajo (0-1 % por sitio), no siendo probablemente un factor condicionante de la reducida distribución de la planta. En R. rubiginosa, ese porcentaje fue alto (31-75 % de frutos infestados por sitio), pero solo el 2-8 % de los aquenios estaban infestados. Considerando los sitios analizados, la distribución a nivel regional de la infestación por M. aculeatus en las especies de rosas estudiadas es reducida. El tama o del fruto no es afectado por la infestación del insecto. Los resultados de este trabajo muestran un bajo impacto actual de M. aculeatus en el control natural de la invasión de las rosas en la región andina de Argentina. Sin embargo, dado que las poblaciones de M. aculeatus podrían ser afectadas por la temperatura, un cambio en esta variable podría incrementar la prevalencia de infestación de las semillas de estos arbustos a mediano y largo plazo. Megastigmus aculeatus Swederus (Hymenoptera: Chalcidoidea) infest Rosa species seeds both at the origin and invasion areas. The wasp larvae develop by consuming the entire seed. The M. aculeatus infestation was analyzed at different Rosa canina L. and Rosa rubiginosa L. populations and at isolated plants of Rosa multiflora Thunb. at Norwestern Patagonian natural areas of Argentina. In R. rubiginosa, the most abundant species, we studied the wasp infestation prevalence and success and the possible infestation effect on fruit size. In this paper we registered the first records of R. canina and R. rubiginosa as host plants for M. aculeatus in wild areas of Argentina and we verified the absence of the wasp in R. multiflora fruits. In R. canina the percentage of infected fruits by M. aculeatus was low (0-1 % per site) not being probably a conditioning factor
Dietary analysis of Homonota darwini (Squamata: Gekkoni-dae) in Northern Patagonia
Marcelo E. KUN, Carla PIANTONI, John D. KRENZ, Nora R. IBARGüENGOYTíA
Current Zoology , 2010,
Abstract: Our study investigated the diet of the southernmost gecko in the world, Homonota darwini. Fifty-three specimens were captured during spring and summer in four locations in Patagonia, Argentina. The stomach contents of the specimens were identified, and we found that prey consisted of six main groups: Coleoptera, Hymenoptera, Homoptera and Araneae, and the adults and larvae of moth Lepidoptera. Lepidoptera was the major dietary component. The presence of ants and moths as common prey suggests an ambush feeding strategy. In spring, females consumed more ants than males although no other dietary differences between males and females were evident. We found nine geckos with empty stomachs and six parasitized by nematodes. Presence of empty stomachs corroborates previous observations of other nocturnal geckos and non-gecko lizards. Reduced foraging success of nocturnal lizards could be due to difficulty in prey detection due to dim light, reduced or erratic activity of insect prey at night, or shorter activity times of geckos relative to diurnal success. Sex and season were not associated with the incidence of empty stomachs. Principal component analysis showed that four food alternatives correlated with season. The constraint of nocturnality, coupled with low night-time temperatures restricting feeding to only a few hours after sunset, appear to have caused a generality of diet which may limit energy acquisition. We conclude that H. darwini is an arthropod generalist and likely an ambush forager, as are many other nocturnal gekkonids [Current Zoology 56 (4): 406–410, 2010].
Dieta del águila Mora (Geranoaetus melanoleucus) en una transecta oeste-este en el ecotono norpatagónico
Trejo,Ana; Kun,Marcelo; Seijas,Susana;
El hornero , 2006,
Abstract: the diet of black-chested buzzard-eagle (geranoaetus melanoleucus) was studied during 2002-2003 breeding season in five sites located on a west-east transect in the ecotone between the subantarctic forests and the patagonian steppe, in andean río negro province, argentina. this area is characterized by a heterogeneous habitat determined by a west-east decreasing precipitation gradient. we identified 525 preys from 271 pellets collected under perches or nests. prey composition (considering the total sample) was: 51% rodents (mostly native sigmodontine rodents under 200 g), 25% lagomorphs, 3% other mammals, 8% birds, 1% reptiles, and 12% arthropods. our results contrast with those of the rest of the studies on this bird made both in chile and argentina, where lagomorphs predominate in the diet and sigmodontine rodents made up a lesser proportion. analyzing the diet from different localities, the western (more humid) sites presented rodent-dominated diets, whereas the eastern (more arid) ones presented lagomorph-dominated diets. we attribute these differences to the abundance of sigmodontine rodents in the more humid sites due to habitat heterogeneity, and to the eagle's opportunistic feeding behaviour.
Myiasis gastrointestinal humana por Eristalis tenax
Kun,Marcelo; Kreiter,Ana; Semenas,Liliana;
Revista de Saúde Pública , 1998, DOI: 10.1590/S0034-89101998000400009
Abstract: the myiasis observed in bariloche are characterized and the probable conditions under which the infestations took place established. the larvae obtained from faeces of 2 patients were identified as eristalis tenax (diptera: syrphidae) according to hartley (1961) and organización panamericana de la salud keys (1962). these 2 cases of human gastrointestinal myiasis were the first to be registered in bariloche (patagonia, argentina) and their characteristics were similar to those described for this species in other parts of the world. the lack of specific control measures in the domestic water supply system was the most probable cause of the infestation. this event extends the distribution of e. tenax and human gastrointestinal myiasis in south america to 41o 03' s.
The occurrence of Pachytullbergia scabra (Collembola: Pachytullbergiidae) on Pseudocyphellaria granulata (lichenized Ascomycota)
Messuti,María Inés; Kun,Marcelo;
Revista de la Sociedad Entomol?3gica Argentina , 2007,
Abstract: the springtail species pachytullbergia scabra bonet (pachytullbergiidae), previously recorded in austral america inhabiting the surfaces of nothofagus dombeyi (mirb.) oerst. bark, has been collected growing on the epiphytic lichen species pseudocyphellaria granulata (c. bab.) malme. this is the first record of an arthropod-lichen association in the cool temperate forest of argentina.
Myiasis gastrointestinal humana por Eristalis tenax
Kun Marcelo,Kreiter Ana,Semenas Liliana
Revista de Saúde Pública , 1998,
Abstract: Son caracterizadas las myiasis registradas en Bariloche y establecidas las condiciones probables bajo las cuales se produjeron las infestaciones. Las larvas obtenidas a partir de heces de 2 pacientes fueron identificadas como Eristalis tenax (Diptera: Syrphidae) de acuerdo a las claves de Hartley (1961) y Organización Panamericana de la Salud (1962). Estos 2 casos de myiasis gastrointestinal humana constituyen los primeros registrados en Bariloche (Patagonia, Argentina) y sus características responden a las registradas para esta especie de Díptera en otras partes del mundo. La falta de control específico en el sistema domiciliario de suministro de agua ha sido la causa más probable de la infestación. Este registro extiende la distribución de E. tenax y de las myiasis gastrointestinales humanas en América del Sur hasta los 41o 03' S.
The occurrence of Pachytullbergia scabra (Collembola: Pachytullbergiidae) on Pseudocyphellaria granulata (lichenized Ascomycota) La presencia de Pachytullbergia scabra (Collembola: Pachytullbergiidae) sobre Pseudocyphellaria granulata (Ascomycota liquenizados)
María Inés Messuti,Marcelo Kun
Revista de la Sociedad Entomol?3gica Argentina , 2007,
Abstract: The springtail species Pachytullbergia scabra Bonet (Pachytullbergiidae), previously recorded in austral America inhabiting the surfaces of Nothofagus dombeyi (Mirb.) Oerst. bark, has been collected growing on the epiphytic lichen species Pseudocyphellaria granulata (C. Bab.) Malme. This is the first record of an arthropod-lichen association in the cool temperate forest of Argentina. El colémbolo Pachytullbergia scabra Bonet (Pachytullbergiidae), previamente registrada en América austral como habitante de la superficie de la corteza de Nothofagus dombeyi (Mirb.) Oerst., fue coleccionada sobre la especie liquénica Pseudocyphellaria granulata (C. Bab.) Malme. éste es el primer registro de una asociación artrópodo-líquen en los bosques templado-fríos de la Argentina.
Formación institucional y poder: investigando la construcción social de la ciudad
Zunino E.,Hugo Marcelo;
EURE (Santiago) , 2002, DOI: 10.4067/S0250-71612002008400006
Abstract: this article develops a conceptual and methodological framework to study the formation of institutions designed to intervene on fragments of the urban landscape. using some theoretical insights from giddens and foucault, i reformulate the notion of institution, which is here understood as a set of rules operating across functional levels. this approach allows accounting for the power relations that they represent as well as for the channels open for the exercise of power over the population and urban space. likewise, this methodological strategy permits to relate the local conditions under which specific projects are executed and national or global policies. in this vein, i suggest using the typology of social rules suggested by ostrom in a five-stage research strategy. finally, i discuss the theoretical implications of this line of investigation, stressing its utility to decipher power relations implicated in processes of urban change
Parasitic castration in Fissurella crassa (Archaeogastropoda) due to an adult Digenea, Proctoeces lintoni (Fellodistomidae)
Oliva, Marcelo E.;
Memórias do Instituto Oswaldo Cruz , 1992, DOI: 10.1590/S0074-02761992000100007
Abstract: specimens of fissurella crassa (archaeogastropoda) from ilo, southern perú, are infected with the adult stage of the digenetic trematode proctoeces lintoni (fellodistomidae). the histopatological analysis of the male and female gonads show a strong effect of the parasite on the structure and function of these organs. p. lintoni live unencysted in the gonads, and the main mechanical damage is originated by the action of a well developed acetabulum. chemical actions of parasitic secretions may also be involved. the infected gonads show altered structure and the gametogenic processes is aborted. there is no evidence of hemocytic response, but leucocite infiltration is evident at least in male infected gonads. an increased content of polysaccarides is evident in infected gonads.
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