998 resultados para Mingan Islands


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Despite the professed claims of microcredit alleviating poverty, little is known about what kind of credit contract is suitable for extremely poor households, also called the ultra-poor. To fill this knowledge gap, we initiated a field experiment in the river islands of northern Bangladesh, where a substantial portion of dwellers could be categorized as ultra-poor due to cyclic floods. We randomly offered four types of loans to such dwellers: regular small cash loans with one-year maturity, large cash loans with three-year maturity both with and without a one-year grace period, and in-kind livestock loans with three-year maturity and a one-year grace period. We compared uptake rates as well as the determinants of uptake and found that the uptake rate is the lowest for the regular contract, followed by the in-kind contract. Contrary to prior belief, we also found that the microcredit demand by the ultra-poor is not necessarily small, and in particular the ultra-poor are significantly more likely to join a microcredit program than the moderately poor if a grace period with longer maturity is attached to a large amount of credit, irrespective of whether the credit is provided in cash or in kind. This paper provides evidence that a typical microcredit contract with one-year maturity and without a grace period is not attractive to the ultra-poor. Microfinance institutions may need to design better credit contracts to address the poor's needs.

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Geodetic volcano monitoring in Tenerife has mainly focused on the Las Cañadas Caldera, where a geodetic micronetwork and a levelling profile are located. A sensitivity test of this geodetic network showed that it should be extended to cover the whole island for volcano monitoring purposes. Furthermore, InSAR allowed detecting two unexpected movements that were beyond the scope of the traditional geodetic network. These two facts prompted us to design and observe a GPS network covering the whole of Tenerife that was monitored in August 2000. The results obtained were accurate to one centimetre, and confirm one of the deformations, although they were not definitive enough to confirm the second one. Furthermore, new cases of possible subsidence have been detected in areas where InSAR could not be used to measure deformation due to low coherence. A first modelling attempt has been made using a very simple model and its results seem to indicate that the deformation observed and the groundwater level variation in the island may be related. Future observations will be necessary for further validation and to study the time evolution of the displacements, carry out interpretation work using different types of data (gravity, gases, etc) and develop models that represent the island more closely. The results obtained are important because they might affect the geodetic volcano monitoring on the island, which will only be really useful if it is capable of distinguishing between displacements that might be linked to volcanic activity and those produced by other causes. One important result in this work is that a new geodetic monitoring system based on two complementary techniques, InSAR and GPS, has been set up on Tenerife island. This the first time that the whole surface of any of the volcanic Canary Islands has been covered with a single network for this purpose. This research has displayed the need for further similar studies in the Canary Islands, at least on the islands which pose a greater risk of volcanic reactivation, such as Lanzarote and La Palma, where InSAR techniques have been used already.

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The accuracy of Tomás López´s historical cartography of the Canary Islands included in the “Atlas Particular” of the Kingdoms of Spain, Portugal and Adjacent Islands” is analyzed. For this purpose, we propose a methodology based on Geographic Information Systems (GIS), a comparison of digitized historical cartography population centres with current ones. This study shows that the lineal error value is small for the smaller islands: Lanzarote, El Hierro, La Palma and La Gomera. In the large islands of Tenerife, Fuerteventura and Gran Canaria, the error is smaller in central zones but increases towards the coast. This indicates that Tomás López began his cartography starting from central island zones, accumulating errors due to lack of geodetic references as he moved toward the coast.

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In volcanic islands, the rainfall regime and its torrential nature, together with the steep slopes and the soil types present are considered to be some of the main factors affecting forest hydrology and soil conservation. In such environments, rain regime is generally irregular and characterized by short and intense rainfalls, which could cause destructive flows at times, followed by long periods of rain absence. The volcanic nature of these islands have as a direct resultant steep slopes which influences the runoff volume and speed, as well as the amount of topsoil susceptible to be detached and transported downstream. The soil type also affects the susceptibility to erosion processes. Andisols are the most typical soil on volcanic islands. Their particularities derive their mineral constituents, called short-range-order products, which provide these soils with an increased structural stability, which in turn reduces their susceptibility to erosion. However, the land use changes and the environmental factors such as rain regime and steep slopes may be determinant factor in destabilizing these soils and ultimately a cause for soil erosion and runoffs, which become a threat to the population downstream. Green barriers have been traditionally used to prevent or reduce these processes, also to enhance the dew effect and the fog water collection, and as a firebreak which acts as a barrier to slow or stop the progress of a wildfire. Wooded species present and subsequently their performance have a major influence on their effectiveness. The use of this natural erosion and fire control methods on volcanic islands is discussed in this paper.

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Massive integration of renewable energy sources in electrical power systems of remote islands is a subject of current interest. The increasing cost of fossil fuels, transport costs to isolated sites and environmental concerns constitute a serious drawback to the use of conventional fossil fuel plants. In a weak electrical grid, as it is typical on an island, if a large amount of conventional generation is substituted by renewable energy sources, power system safety and stability can be compromised, in the case of large grid disturbances. In this work, a model for transient stability analysis of an isolated electrical grid exclusively fed from a combination of renewable energy sources has been studied. This new generation model will be installed in El Hierro Island, in Spain. Additionally, an operation strategy to coordinate the generation units (wind, hydro) is also established. Attention is given to the assessment of inertial energy and reactive current to guarantee power system stability against large disturbances. The effectiveness of the proposed strategy is shown by means of simulation results.

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In 2005 the Directorate General for Industrial Development and Technological Innovation of the Canary Islands proceeded to carry out a project to measure the behavioral skills of various government agencies and companies in the Canary Islands in order to prepare a White Paper to assess the most effective measures for the stimulation of innovation in this autonomous community and to facilitate the objectives of public subsidies. This paper shows a portion of the work performed comparing the activity oriented towards innovation and the one aimed at sustaining the status quo of the organizations in the sample.

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More than 20 mega-landslides have been described in the Canary Islands affecting the flanks of the volcanic edifices. Gliimar and La Orotava landslides, in Tenerife, are two exceptional cases due to their huge dimensions and outstanding geomorphological features. The estimated volume of these landslides exceed tens of cubic km. Tsunami deposits have been also identified in some of the islands of the archipelago probably associated to the large landslides of the islands flanks. An investigation has been carried out to explain the causes of these large instability processes and their failure mechanisms. One of the main aspects investigated was the geomechanical characteristics of the volcanic rock masses, specially the hyaloclastite rocks forming the substratum underlying the emerged volcanic building. The low strength and high deformability properties of these rocks have played a fundamental role on the stability of the island flanks. The results have shown the gravitational origin of these instability processes as the main failure mechanism. Volcanic eruptions or large earthquakes could be contributing factors to the instability, but according with the data obtained in Gliimar and La Orotava cases they are not necessary as triggering factors. As a result of the field work carried out in the frame of the project, three large tsunami deposits have been identified in the islands of Lanzarote, Tenerifc and Gran Canaria attributed to rnega-Iandslides, possibly related to Guimar and La Orotava. A Sumrnary of their main features is described.

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Análisis del riesgo volcánico. We show the preliminary results of the study of 561 volcanic bombs ejected from a pyroclastic cone during the 1730-1736 Timanfaya eruption (Lanzarote, Canary Islands). This cone displays the highest concentration of big bombs (major axis higher than 1 m) of Timanfaya. More than 560 bombs have been studied to calculate their reach. The results suggest that bombs of 1t have a reach of 409 m, while bombs up to 28 t have a reach of 248 m. These data may be used to define a security area once a vent has been opened, but also to calculate other data such the initial velocity of ejection. The geomorphological analysis and the study of the deposits also contribute to better understand an undocumented episode of the Timanfaya eruption and also provide important data for volcanic bombs modeling for volcanic hazard analysis.

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Se ha realizado un estudio dendrogeomorfológico utilizando las heridas de los árboles como indicadores de paleoinundaciones.