926 resultados para CORDILLERA CENTRAL DE COSTA RICA
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The crescent increasing demand of the electric power in Brazil has stimulated the implantation of Small Central Hydroelectric Power (SCHP) in several regions of the country. However, the silting up of the reservoirs is one of the main problems faced by hydroelectric power plants and SCHP. In this context, this research aimed evaluate the phenomenology and propose the enforcement of appropriate bioengineering techniques to control the intense erosive process of the hydrographical basin of the “Alto Rio Sucuriú,” that cause silting up of the reservoirs of the SCHP Costa Rica, located in the municipal district of Costa Rica (MS). In order to identify the phenomenology of the main falling in of this basin, a diagnosis of the conditions of the physical environment of the region (climate, geology, pedology, hydrology, and use of the ground) was realized. A surveying was also realized to specify the geometric feature of the falling in using the Total Station of the Ruide brand, series RTS 860R and the geodetic GPS of the Ashtech brand and the data obtained was used on the preparation of the Digital Elevation Model (DEM) of the falling in. Based on this diagnosis an official register of the falling in was done with identification of the different types of present erosion. Due to the advanced erosive stage of the falling in researched, the use of bioengineering techniques could be the best solution considering that the traditional engineering techniques make use of heavy material like concrete, iron and large machines that besides causing higher impact to the natural and esthetic aspects of the environment also require a higher investment of capital. This research establish a great cooperation to the knowledge of the erosive process and of the rehabilitation of the degraded areas with application of bioengineering techniques not only hydrographical basin of “Alto Rio Sucuriú” but also to other basins that show similar situation
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Pós-graduação em Engenharia Mecânica - FEG
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An updated checklist of the Cerambycidae of Costa Rica is presented. This new version includes 1,071 species and subspecies in 429 genera, 69 tribes, and six subfamilies. Of these, 181 are new country records and 136 species are known only from Costa Rica. In addition, provincial distribution data are provided for each species. The checklist supports a wealth of scientific literature in many other groups of flora and fauna indicating Costa Rica has high species richness of cerambycid beetles. Se presenta una lista actualizada de los Cerambycidae de Costa Rica. Esta nueva versión incluye 1.071 especies y subespecies en 429 géneros, 69 tribus, y seis subfamilias. De estas, 181 son nuevos registros para el país y 136 especies se conocen solamente de Costa Rica. Adicionalmente, para cada especie se incluyen datos sobre su presencia en las diferentes provincias. La lista concuerda con una gran cantidad de literatura científica en muchos otros grupos de flora y fauna que muestran que Costa Rica tiene una alta riqueza de especies.
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This thesis explores adolescent pregnancy in San Jose, Costa Rica and examines a school-based pregnancy prevention intervention. The relationships between school, gender and risk of adolescent pregnancy are also analyzed, and recommendations are made for effective pregnancy prevention programming. The Purral region of Guadalupe on the outskirts of San Jose, Costa Rica, suffers a higher rate of adolescent pregnancy compared to the rest of the country. In response to this problem, the International Health Central American Institute (IHCAI) implemented a sexual health education program in two local secondary schools in 2006. Very little information about the program is available. It is known that the program was initially evaluated through assessments of the participants’ knowledge before and after the educational sessions. There was no evaluation of the youth attitudes or behaviors, adolescent pregnancies, or long-term impact. The author worked with IHCAI in San Jose, Costa Rica to perform an assessment of the longer term effects of this sexual health education program. They developed a questionnaire to evaluate the knowledge, attitudes, and behaviors surrounding sexual health of youth in the Purral community. Researchers at IHCAI later used this survey to collect data from adolescents who had participated in the educational intervention and those who had not. This thesis analyzes the data collected by IHCAI to assess the effectiveness of the - 2 - educational intervention and the influence of other factors on the knowledge, attitudes, and behaviors of adolescents in the Purral region. The thesis begins with an overview of adolescent pregnancy, Costa Rica and the Purral region, and a description of the education intervention implemented by IHCAI. The research goal, logic model, and methods are then described. The results are reported, and the thesis then concludes with discussion of the results as well as study limitations and recommendations for future research and intervention. This thesis will be used to guide IHCAI’s continuation and expansion of adolescent pregnancy prevention programming.
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Resolving flow geometry in the mantle wedge is central to understanding the thermal and chemical structure of subduction zones, subducting plate dehydration, and melting that leads to arc volcanism, which can threaten large populations and alter climate through gas and particle emission. Here we show that isotope geochemistry and seismic velocity anisotropy provide strong evidence for trench-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua. This finding contradicts classical models, which predict trench-normal flow owing to the overlying wedge mantle being dragged downwards by the subducting plate. The isotopic signature of central Costa Rican volcanic rocks is not consistent with its derivation from the mantle wedge (Feigenson et al., 2004, doi:10.1029/2003GC000621; Herrstom et al., 1995, doi:10.1130/0091-7613(1995)023<0617:VILCAW>2.3.CO;2; Abratis and Woerner, 2001) or eroded fore-arc complexes (Goss and Kay, 2006, doi:10.1029/2005GC001163) but instead from seamounts of the Galapagos hotspot track on the subducting Cocos plate. This isotopic signature decreases continuously from central Costa Rica to northwestern Nicaragua. As the age of the isotopic signature beneath Costa Rica can be constrained and its transport distance is known, minimum northwestward flow rates can be estimated (~63-190 mm/yr) and are comparable to the magnitude of subducting Cocos plate motion (approx85 mm/yr). Trench-parallel flow needs to be taken into account in models evaluating thermal and chemical structure and melt generation in subduction zones.
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Water is fundamental to human life and the availability of freshwater is often a constraint on human welfare and economic development. Consequently, the potential effects of global changes on hydrology and water resources are considered among the most severe and vital ones. Water scarcity is one of the main problems in the rural communities of Central America, as a result of an important degradation of catchment areas and the over-exploitation of aquifers. The present Thesis is focused on two critical aspects of global changes over water resources: (1) the potential effects of climate change on water quantity and (2) the impacts of land cover and land use changes on the hydrological processes and water cycle. Costa Rica is among the few developing countries that have recently achieved a land use transition with a net increase in forest cover. Osa Region in South Pacific Costa Rica is an appealing study site to assess water supply management plans and to measure the effects of deforestation, forest transitions and climate change projections reported in the region. Rural Community Water Supply systems (ASADAS) in Osa are dealing with an increasing demand of freshwater due to the growing population and the change in the way of life in the rural livelihoods. Land cover mosaics which have resulted from the above mentioned processes are characterized by the abandonment of marginal farmland with the spread over these former grasslands of high return crops and the expansion of secondary forests due to reforestation initiatives. These land use changes have a significant impact on runoff generation in priority water-supply catchments in the humid tropics, as evidenced by the analysis of the Tinoco Experimental Catchment in the Southern Pacific area of Costa Rica. The monitoring system assesses the effects of the different land uses on the runoff responses and on the general water cycle of the basin. Runoff responses at plot scale are analyzed for secondary forests, oil palm plantations, forest plantations and grasslands. The Oil palm plantation plot presented the highest runoff coefficient (mean RC=32.6%), twice that measured under grasslands (mean RC=15.3%) and 20-fold greater than in secondary forest (mean RC=1.7%). A Thornthwaite-type water balance is proposed to assess the impact of land cover and climate change scenarios over water availability for rural communities in Osa Region. Climate change projections were obtained by the downscaling of BCM2, CNCM3 and ECHAM5 models. Precipitation and temperature were averaged and conveyed by the A1B, A2 and B1 IPCC climate scenario for 2030, 2060 and 2080. Precipitation simulations exhibit a positive increase during the dry season for the three scenarios and a decrease during the rainy season, with the highest magnitude (up to 25%) by the end of the 21st century under scenario B1. Monthly mean temperature simulations increase for the three scenarios throughout the year with a maximum increase during the dry season of 5% under A1B and A2 scenarios and 4% under B1 scenario. The Thornthwaite-type Water Balance model indicates important decreases of water surplus for the three climate scenarios during the rainy season, with a maximum decrease on May, which under A1B scenario drop up to 20%, under A2 up to 40% and under B1 scenario drop up to almost 60%. Land cover scenarios were created taking into account current land cover dynamics of the region. Land cover scenario 1 projects a deforestation situation, with forests decreasing up to 15% due to urbanization of the upper catchment areas; land cover scenario 2 projects a forest recovery situation where forested areas increase due to grassland abandonment on areas with more than 30% of slope. Deforestation scenario projects an annual water surplus decrease of 15% while the reforestation scenario projects a water surplus increase of almost 25%. This water balance analysis indicates that climate scenarios are equal contributors as land cover scenarios to future water resource estimations.
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La investigación tiene como objetivo central la confección de dos estudios de caso de las políticas de igualdad de Chile y Costa Rica, que enfatizan en sus concepciones de igualdad y estrategias, con el propósito de explicitar las bases conceptuales y programáticas de la igualdad entre mujeres y hombres como problema público. Las políticas de igualdad son relativamente recientes en América Latina y el Caribe. Su desarrollo toma fuerza en la década de los noventa del siglo pasado y son motivadas principalmente por un marco de compromisos y acuerdos supranacionales (mundiales y regionales) de carácter jurídico, que emanan de Convenciones y legislación nacional y político, que derivan de la IV Conferencia Mundial de la Mujer (Beijing 1995) y su Plataforma de Acción, Conferencias Mundiales y Conferencias Regionales. El énfasis se pone en la fase de formulación de las políticas de igualdad, que comprende la definición de su modelo causal y la formulación de su programa de actuación político– administrativo, en concreto el análisis de los objetivos, instrumentos y procesos que deberán ponerse en práctica para el logro de la igualdad entre mujeres y hombres. Para tal efecto y utilizando el estudio de casos como método de investigación, se construyen y analizan los casos de políticas de igualdad de Chile y Costa Rica, tomando como referente una estructura y orientaciones metodológicas similares. El marco conceptual de la investigación profundiza en las definiciones y elementos que caracterizan a las políticas públicas; el género como categoría de análisis; la delimitación y alcance de los conceptos de no discriminación, equidad e igualdad; las definiciones de políticas de igualdad de oportunidades, políticas de equidad de género y políticas de igualdad de género; y la transversalidad de género como estrategia de política pública...
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The wild cats and the livestock farmers are part of the space conflict in the rural areas in Latin America. In this sense, this conflict causes a discomfort among the livestock producers due to the loss of animals and, consequently, it also causes a negative reaction towards the wild cats leading such reaction into the elimination of the wild cats per se. Although, there have been some initiatives have tried to approach such conflict by recommending mitigation and prevention measurements to the producers, these measurements are undertaken without coordination. For this reason, the following project presents a planning tool that can ease the coordination processes undertaken for the solving of the conflict between human beings and wild cats.
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Isla del Coco (Cocos Island) is a small volcanic island located in the Pacific 500 km west of Costa Rica. Three collecting trips to Isla del Coco, in addition to herbarium research, were completed in order to assess the floristic diversity of the island. The current flora of Isla del Coco contains 262 plant species of which 37 (19.4%) are endemic. This study reports 58 species as new to the island. Seventy-one species (27.1%) were identified as introduced by humans. In addition, five potentially invasive plant species are identified. Seven vegetation types are identified on the island: bayshore, coastal cliff, riparian, low elevation humid forest, high elevation cloud forest, landslide and islet. ^ The biogeographic affinities of the native and endemic species are with Central America/northern South America and to a lesser extent, the Caribbean. Endemic species in the genus Epidendrum were investigated to determine whether an insular radiation event had produced two species found on Isla del Coco. Phylogenetic analysis of the internal transcribed spacer (ITS) of nuclear ribosomal DNA was not able to disprove that the endemic species in this genus are not sister species. Molecular biogeographic analyses of ITS sequence data determined that the Isla del Coco endemic species in the genera Epidendrum, Pilea and Psychotria are most closely related to Central American/northern South American taxa. No biogeographical links were found between the floras of Isla del Coco and the Galápagos Islands. ^ The native and endemic plant diversity of Isla del Coco is threatened with habitat degradation by introduced pigs and deer, and to a lesser extent, by exotic plant species. The IUCN Red List and RAREplants criteria were used to assess the extinction threat for the 37 endemic plant taxa found on the island. All of the endemic species are considered threatened with extinction at the Critically Endangered (CR) by the IUCN criteria or either CR or Endangered (EN) using RAREplants methodology. ^
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Amphibian populations are declining even in pristine areas in many parts of the world, and in the Neotropics most such enigmatic amphibian declines have occurred in mid- to high-elevation sites. However, amphibian populations have also declined at La Selva Biological Station in the lowlands of Costa Rica, and similar declines in populations of lizards have occurred at the site as well. To set the stage for describing amphibian declines at La Selva, I thoroughly review knowledge of amphibian decline and amphibian conservation in Central America: I describe general patterns in biodiversity, evaluate major patterns in and ecological correlates of threat status, review trends in basic and applied conservation literature, and recommend directions for future research. I then synthesize data on population densities of amphibians, as well as ecologically similar reptiles, over a 35-year periods using quantitative datasets from a range of studies. This synthesis identifies assemblage-wide declines of approximately 75% for both amphibians and reptiles between 1970 and 2005. Because these declines defy patterns most commonly reported in the Neotropics, it is difficult to assess causality evoking known processes associated with enigmatic decline events. I conduct a 12-month pathogen surveillance program to evaluate infection of frogs by the amphibian chytrid fungus, an emerging pathogen linked to decline events worldwide Although lowland forests are generally believed to be too warm for presence or adverse population effects of chytridiomycosis, I present evidence for seasonal patterns in infection prevalence with highest prevalence in the coolest parts of the year. Finally, I conducted a 16-month field experiment to explore the role of changes to dynamics of leaf litter, a critical resource for both frogs and lizards. Population responses by frogs and lizards indicate that litter regulates population densities of frogs and lizards, particularly those species with the highest decline rate. My work illustrates that sites that are assumed to be pristine are likely impacted by a variety of novel stressors, and that even fauna within protected areas may be suffering unexpected declines.