984 resultados para Population Dynamics


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This study aims to understand the sociospatial transformations resulting from the depopulation of the fields and their effects on the rural landscape of Arroio do Só in Santa Maria - RS. To this end, we attempted to identify changes in the way of life of rural people, their activities and relationships and understand how this process has occurred, its causes and its impact on quality of life and social structure of the population that remained in place. The discussion on the modernization of agriculture is key to understanding this process. This district was chosen as a research site because it is a town that, in the past, had a very big socioeconomic dynamism, and now, according to the bankruptcy of several companies and the consequent emigration of much of the population, the sociospatial dynamic has changed. It was collected data from a secondary source of FIBGE and FEE in order to periodize population dynamics of the district, county and state. The qualitative research was conducted through interviews with the subjects in the field and their representatives, with the help of the Field Diary

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La década de 1990 significó para Argentina la profundización de la práctica de un nuevo orden que respondía al modelo neoliberal. Dicho modelo creó condiciones de inestabilidad, corrupción, aumento de la desocupación y concentración de la riqueza, lo cual tendría una reconocida incidencia en la evolución de la miseria en el Norte Grande Argentino (NGA), el área más carente del país según distintas variables sociodemográficas. En este territorio se identificaron los núcleos más críticos en relación a la concentración de miseria a principios y finales de dicha década. Uno de estos núcleos corresponde al Chaco Aborigen. La miseria presentó avances, persistencias y descenso en este núcleo. En este trabajo se analizan los principales procesos territoriales ocurridos en la década en cada uno de estos sectores, los cuales podrían asociarse con determinados comportamientos. Dentro de tales procesos se pretende indagar sobre los cambios en las grandes masas de cultivo, la ganadería, la cantidad y superficie de las explotaciones agropecuarias y la dinámica de la población. Como fuentes de información se utilizaron los Censos Nacionales de Población, Hogares y Viviendas de 1991 y 2001, los Censos Nacionales Agropecuarios de 1988 y 2002 y las estadísticas vitales del periodo intercensal.

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This study aims to understand the sociospatial transformations resulting from the depopulation of the fields and their effects on the rural landscape of Arroio do Só in Santa Maria - RS. To this end, we attempted to identify changes in the way of life of rural people, their activities and relationships and understand how this process has occurred, its causes and its impact on quality of life and social structure of the population that remained in place. The discussion on the modernization of agriculture is key to understanding this process. This district was chosen as a research site because it is a town that, in the past, had a very big socioeconomic dynamism, and now, according to the bankruptcy of several companies and the consequent emigration of much of the population, the sociospatial dynamic has changed. It was collected data from a secondary source of FIBGE and FEE in order to periodize population dynamics of the district, county and state. The qualitative research was conducted through interviews with the subjects in the field and their representatives, with the help of the Field Diary

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La década de 1990 significó para Argentina la profundización de la práctica de un nuevo orden que respondía al modelo neoliberal. Dicho modelo creó condiciones de inestabilidad, corrupción, aumento de la desocupación y concentración de la riqueza, lo cual tendría una reconocida incidencia en la evolución de la miseria en el Norte Grande Argentino (NGA), el área más carente del país según distintas variables sociodemográficas. En este territorio se identificaron los núcleos más críticos en relación a la concentración de miseria a principios y finales de dicha década. Uno de estos núcleos corresponde al Chaco Aborigen. La miseria presentó avances, persistencias y descenso en este núcleo. En este trabajo se analizan los principales procesos territoriales ocurridos en la década en cada uno de estos sectores, los cuales podrían asociarse con determinados comportamientos. Dentro de tales procesos se pretende indagar sobre los cambios en las grandes masas de cultivo, la ganadería, la cantidad y superficie de las explotaciones agropecuarias y la dinámica de la población. Como fuentes de información se utilizaron los Censos Nacionales de Población, Hogares y Viviendas de 1991 y 2001, los Censos Nacionales Agropecuarios de 1988 y 2002 y las estadísticas vitales del periodo intercensal.

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The development of the ecosystem approach and models for the management of ocean marine resources requires easy access to standard validated datasets of historical catch data for the main exploited species, together with the model estimates achieved from these data, allowing models inter-comparison and evaluation of model skills. North Atlantic albacore tuna is exploited all year round by longline and in summer and autumn by surface fisheries and fishery statistics compiled by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Catch and effort with geographical coordinates at monthly spatial resolution of 1° or 5° squares were extracted for this species with a careful definition of fisheries and data screening. Length frequencies of catch were also extracted according to the definition of fisheries for the period 1956-2010. Using these data, an application of the spatial ecosystem and population dynamics model (SEAPODYM) was developed for the North Atlantic albacore population and fisheries and provided the first spatially explicit estimate of albacore density in the North Atlantic by life stage. These densities by life stage (larval recruits, young immature fish adult mature fish and total biomass) are provided in gridded file (Netcdf) at resolution of 2° x 2° x month.

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This study aims to understand the sociospatial transformations resulting from the depopulation of the fields and their effects on the rural landscape of Arroio do Só in Santa Maria - RS. To this end, we attempted to identify changes in the way of life of rural people, their activities and relationships and understand how this process has occurred, its causes and its impact on quality of life and social structure of the population that remained in place. The discussion on the modernization of agriculture is key to understanding this process. This district was chosen as a research site because it is a town that, in the past, had a very big socioeconomic dynamism, and now, according to the bankruptcy of several companies and the consequent emigration of much of the population, the sociospatial dynamic has changed. It was collected data from a secondary source of FIBGE and FEE in order to periodize population dynamics of the district, county and state. The qualitative research was conducted through interviews with the subjects in the field and their representatives, with the help of the Field Diary

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La década de 1990 significó para Argentina la profundización de la práctica de un nuevo orden que respondía al modelo neoliberal. Dicho modelo creó condiciones de inestabilidad, corrupción, aumento de la desocupación y concentración de la riqueza, lo cual tendría una reconocida incidencia en la evolución de la miseria en el Norte Grande Argentino (NGA), el área más carente del país según distintas variables sociodemográficas. En este territorio se identificaron los núcleos más críticos en relación a la concentración de miseria a principios y finales de dicha década. Uno de estos núcleos corresponde al Chaco Aborigen. La miseria presentó avances, persistencias y descenso en este núcleo. En este trabajo se analizan los principales procesos territoriales ocurridos en la década en cada uno de estos sectores, los cuales podrían asociarse con determinados comportamientos. Dentro de tales procesos se pretende indagar sobre los cambios en las grandes masas de cultivo, la ganadería, la cantidad y superficie de las explotaciones agropecuarias y la dinámica de la población. Como fuentes de información se utilizaron los Censos Nacionales de Población, Hogares y Viviendas de 1991 y 2001, los Censos Nacionales Agropecuarios de 1988 y 2002 y las estadísticas vitales del periodo intercensal.

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The spatial and temporal dynamics of seagrasses have been well studied at the leaf to patch scales, however, the link to large spatial extent landscape and population dynamics is still unresolved in seagrass ecology. Traditional remote sensing approaches have lacked the temporal resolution and consistency to appropriately address this issue. This study uses two high temporal resolution time-series of thematic seagrass cover maps to examine the spatial and temporal dynamics of seagrass at both an inter- and intra-annual time scales, one of the first globally to do so at this scale. Previous work by the authors developed an object-based approach to map seagrass cover level distribution from a long term archive of Landsat TM and ETM+ images on the Eastern Banks (~200 km**2), Moreton Bay, Australia. In this work a range of trend and time-series analysis methods are demonstrated for a time-series of 23 annual maps from 1988 to 2010 and a time-series of 16 monthly maps during 2008-2010. Significant new insight was presented regarding the inter- and intra-annual dynamics of seagrass persistence over time, seagrass cover level variability, seagrass cover level trajectory, and change in area of seagrass and cover levels over time. Overall we found that there was no significant decline in total seagrass area on the Eastern Banks, but there was a significant decline in seagrass cover level condition. A case study of two smaller communities within the Eastern Banks that experienced a decline in both overall seagrass area and condition are examined in detail, highlighting possible differences in environmental and process drivers. We demonstrate how trend and time-series analysis enabled seagrass distribution to be appropriately assessed in context of its spatial and temporal history and provides the ability to not only quantify change, but also describe the type of change. We also demonstrate the potential use of time-series analysis products to investigate seagrass growth and decline as well as the processes that drive it. This study demonstrates clear benefits over traditional seagrass mapping and monitoring approaches, and provides a proof of concept for the use of trend and time-series analysis of remotely sensed seagrass products to benefit current endeavours in seagrass ecology.

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Snow cover has dramatic effects on the structure and functioning of Arctic ecosystems in winter. In the tundra, the subnivean space is the primary habitat of wintering small mammals and may be critical for their survival and reproduction. We have investigated the effects of snow cover and habitat features on the distributions of collared lemming (Dicrostonyx groenlandicus) and brown lemming (Lemmus trimucronatus) winter nests, as well as on their probabilities of reproduction and predation by stoats (Mustela erminea) and arctic foxes (Vulpes lagopus). We sampled 193 lemming winter nests and measured habitat features at all of these nests and at random sites at two spatial scales. We also monitored overwinter ground temperature at a subsample of nest and random sites. Our results demonstrate that nests were primarily located in areas with high micro-topography heterogeneity, steep slopes, deep snow cover providing thermal protection (reduced daily temperature fluctuations) and a high abundance of mosses. The probability of reproduction increased in collared lemming nests at low elevation and in brown lemming nests with high availability of some graminoid species. The probability of predation by stoats was density dependent and was higher in nests used by collared lemmings. Snow cover did not affect the probability of predation of lemming nests by stoats, but deep snow cover limited predation attempts by arctic foxes. We conclude that snow cover plays a key role in the spatial structure of wintering lemming populations and potentially in their population dynamics in the Arctic.