993 resultados para intra-guild predation


Relevância:

20.00% 20.00%

Publicador:

Resumo:

En este trabajo se intenta dar cuenta del proceso de construcción de nuestro objeto de estudio. Si bien, se parte de una preocupación que se vincula con la acción pública en materia habitacional, se propone un análisis desde la perspectiva de lugar de la vivienda social en la ciudad. Para ello, se tiene en cuenta tanto los procesos estructurales que se desenvuelven en el mercado suelo urbano, como los efectos de lugar perspectiva desde la perspectiva de los habitantes que residen en los nuevos barrios. Los interrogantes que organizan esta propuesta son: ¿Qué idea de ciudad se configura entorno a la política habitacional actual? ¿Cuál es el lugar asignado a la vivienda social en el mercado residencial de localizaciones intra-urbanas? ¿Cómo estos lugares son reconstruidos desde las trayectorias habitacionales de los habitantes?

Relevância:

20.00% 20.00%

Publicador:

Resumo:

El objetivo de esta tesis es analizar el lugar de la vivienda social en la ciudad, partiendo del recorte que propone el Plan Federal de Construcción de Viviendas en el Area Metropolitana de Buenos Aires en el período 2003-2010. Dicho análisis se centra en la identificación de la posición de la vivienda social en el mercado residencial de localizaciones intra-urbanas y la lectura de los efectos de lugar generados por la política en las trayectorias habitacionales de los habitantes. Para ello, por un lado, se considera el lugar asignado a la vivienda social en la ciudad a través de la posición residencial que los nuevos barrios adquieren en la matriz o la estructura externalidades urbanas, considerando el efecto de los mecanismos de mercado en la adquisición de tierra para la construcción de vivienda social. Por otro lado, se analiza el modo en el cual dichos lugares son (re)construidos, apropiados y percibidos por los habitantes a partir de la mudanza a los barrios de viviendas social y las implicancias que la acción pública tiene en la movilidad residencial de los adjudicatarios. Si bien, este estudio parte de una análisis de la política habitacional, el aporte central se encuentra dirigido a indagar el lugar de la vivienda social desde una mirada que considera el mercado de localizaciones intra-urbanas y las trayectorias residenciales de los habitantes. Esta estrategia metodológica descentrada de los núcleos decisionales centrales de la política habitacioanl, busca poner en evidencia la ausencia de la discusión del papel que juega el suelo y localización en el abordaje de la política habitacional y su relación con la dinámica del hábitat popular. Por otro lado, cuestiona la configuración de una política sin sujeto, la cual se encuentra orientada desde una lógica sectorial a la contrucción a un producto-objeto que continúa mostrando diversas limitaciones

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fil: Del Río, Juan Pablo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

El objetivo de este trabajo es comenzar una indagación en la variación de pronombres clíticos acusativos átonos que se hallan vaciados de distinción genérica. En el uso del español de la Argentina, observamos las siguientes expresiones con clíticos acusativos átonos en un mismo hablante: 1.Mi juego es pasarla bien: ir ensayar y bailar. 2.Estoy re enfocada en pasarlo bien. Nos interesa comenzar a indagar en qué casos el hablante elige la forma masculina y en qué casos la femenina. Y, ya que el referente en el discurso queda descartado, ¿cuál es el significado básico de las formas lo y la?, ¿en qué contextos se usa una y otra?, ¿qué quiere comunicar el hablante cuando usa una y cuando usa otra? Con respecto al corpus, las formas en variación que aquí estudiamos pertenecen al registro coloquial. Por este motivo, hemos seleccionado un corpus compuesto por blogs, artículos periodísticos de interés general, entrevistas y foros de discusión de la Argentina.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Downcore cyclic variation in high-resolution nannofossil abundance records from mid-Pliocene equatorial Atlantic ODP Sites 662 and 926 demonstrate the direct response by several Pliocene taxa (notably Discoaster, Sphenolithus and Florisphaera profunda) to orbitally forced climatic variation. In particular, these records display strong obliquity and precessional signals reflecting primarily high latitude, Southern hemisphere changes influencing upwelling intensity and local low-latitude, insolation-driven climatic changes (via the productivity and/or turbidity influence of Amazon-sourced terrigenous material) at Sites 622 and 926 respectively. In seasonal studies of coccolithophorid assemblages, only part of the variation observed can be explained by abiotic processes, so it is perhaps not surprising that in this study few Pliocene nannofossil taxa demonstrate significant correlations with each other or with physical environmental parameters. Only some variance in nannofossil abundances can be explained by the primary controls of temperature and productivity. The rest is attributed to nonlinear responses to climatic changes; biotic processes such as grazing, predation, viral infection and competition, and/or, abiotic factors for which there is no readily available proxy (e.g. salinity). The lack of strong, consistent intra- and inter-relationships of the nannoflora and the environment reflects an ecologically complex, differentiated original community producing a complex integrated signal transmitted into the fossil record.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Seabirds feed heavily on Arctic cod Boreogadus saida during the summer in the Canadian Arctic but little is known of the interactions among birds while foraging and the factors that drive feeding behaviour. The objective of this study was to describe the relationship between seabirds and Arctic cod in a productive feeding area distant from breeding colonies. Transect surveys were completed using standardized count protocols to determine the density of seabirds in Allen Bay, Cornwallis Island, Nunavut. Shore-based observation sites determined seabird foraging behaviour associated with the presence of schools and environmental variables. The density of birds (156 bird/km**2) was high compared to that of other locations in the Canadian Arctic. Several bird species were more active early in the morning and with winds from the south, possibly due to an increase in Arctic cod feeding on zooplankton at the surface. Northern fulmars Fulmarus glacialis and black-legged kittiwakes Rissa tridactyla captured Arctic cod directly from the water; however, they lost nearly 25% of captures to glaucous gulls Larus hyperboreus and parasitic jaegers Stercorarius parasiticus. These kleptoparasitic seabirds benefited the most in Allen Bay obtaining as much as 8 times more Arctic cod than species capturing cod directly. Northern fulmars captured 3 times more Arctic cod from schools, and black-legged kittiwakes captured similar proportions of schooling and non-schooling cod. We conclude that non-schooling Arctic cod are as important as schooling cod as an energy source for seabirds in nearshore areas, such as Allen Bay, during the summer.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Soft corals of the family Xeniidae are particularly abundant in Red Sea coral reefs. Their success may be partly due to a strong defense mechanism against fish predation. To test this, we conducted field and aquarium experiments in which we assessed the antifeeding effect of secondary metabolites of 2 common xeniid species, Ovabunda crenata and Heteroxenia ghardaqensis. In the field experiment, the metabolites of both investigated species reduced feeding on experimental food pellets in the natural population of Red Sea reef fishes by 86 and 92% for O. crenata and H. ghardaqensis, respectively. In the aquarium experiment, natural concentration of crude extract reduced feeding on experimental food pellets in the common reef fish Thalassoma lunare (moon wrasse) by 83 and 85%, respectively. Moon wrasse feeding was even reduced at extract concentrations as low as 12.5% of the natural concentration in living soft coral tissues. To assess the potential of a structural anti-feeding defence, sclerites of O. crenata were extracted and mixed into food pellets at natural, doubled and reduced concentration without and in combination with crude extract at 25% of natural concentration, and tested in an aquarium experiment. The sclerites did not show any effect on the feeding behavior of the moon wrasse indicating that sclerites provide structural support rather than antifeeding defense. H. ghardaqensis lacks sclerites. We conclude that the conspicuous abundance of xeniid soft coral species in the Red Sea is likely a consequence of a strong chemical defence, rather than physical defences, against potential predators.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We investigated the local bird community in Central Sulawesi (Indonesia), with focus on insectivorous species in the agroforestry landscapes adjacent to the Lore Lindu National Park. All study sites were situated at the northern tip of Napu Valley in Central Sulawesi, Indonesia. After an initial mapping of the study area, we selected 15 smallholder cacao plantations as sites for our study in March 2010. These sides were mainly used for bird and bat exclosure experiments. All sited were situated along a local gradient (shade availability on each plantation) and a landscape gradient (distance to primary forest), which were independent from each other. In September 2010 and from February until June 2011, we assessed the bird community on our 15 study sites using monthly point count and mist netting sampling. Point count (20 minutes between 07 am and 10 am and in between the net checking hours) and mist netting surveys (12 hours, between 05:30 am and 17:30 pm) were conducted simultaneously but only once per month on each study site, to avoid habituation of the local bird community to our surveys. Further, point counts were conducted at least 100 m apart from the mist netting sites, to avoid potential disturbance between the two methods. We discarded all observations beyond 50 m (including those individuals that flew over the canopy) from the statistical analysis, as well as recaptures of individuals within identical mist netting rounds.