Search results for "Costa Rica"

A new Aphid genus and species (Hemiptera: Aphididae: Macrosiphini) living on ferns in Costa Rica and Mexico

2013

AbstractAphid species colonising ferns belong to the subfamily Aphidinae (Hemiptera: Aphididae) and the majority of these to the tribe Macrosiphini. A new genus in this tribe and its type species: Gibbomyzus pteridophytorumnew genus, new species, are established. Apterous and alate viviparous females are described from specimens collected on Blechnum buchtienii Rosenstock (Blechnaceae) in Costa Rica and on Pteridium aquilinum (Linnaeus) Kuhn (Dennstaedtiaceae) and an unidentified fern in Mexico. The taxonomic validity of the two new taxa is discussed based on morphological and molecular data. Morphologically, the new genus is compared with genera with swollen siphunculi recorded in the New …

A social and environmental impact assessment of the Crucitas gold mining project in Costa Rica

2014

In 2008 Costa Rica was facing a critical time in its history. A five year mining moratorium had just ended and mining companies were interested in exploring untapped resources in the country. The country was facing important decisions with which development path to take. The Crucitas Mining Project (CMP) was an issue that the whole country had an opinion on; in fact the Constitutional Court of Costa Rica (SALA IV) was debating what to do with the CMP. The purpose of this study was to assist decision makers by providing a well-rounded assessment of the impacts the CMP would have. The goal of this study was to evaluate whether it would be better for Costa Rica to let the mining operation cont…

Abundance and Distribution Patterns of Thunnus albacares in Isla del Coco National Park through Predictive Habitat Suitability Models

2016

Information on the distribution and habitat preferences of ecologically and commercially important species is essential for their management and protection. This is especially important as climate change, pollution, and overfishing change the structure and functioning of pelagic ecosystems. In this study, we used Bayesian hierarchical spatial-temporal models to map the Essential Fish Habitats of the Yellowfin tuna (Thunnus albacares) in the waters around Isla del Coco National Park, Pacific Costa Rica, based on independent underwater observations from 1993 to 2013. We assessed if observed changes in the distribution and abundance of this species are related with habitat characteristics, fis…

“It’s Practically a Must” : Neoliberal Reasons for Foreign Language Learning

2017

Intercultural competence needs of exchange students coming to or going abroad from the university of Costa Rica

2012

Internationalization of higher education is a process in constant development that has occurred over many years. It involves efforts of the entire academic community and the implementation of diverse strategies. Focusing on the academic exchange, the less developed regions face certain particularities that limit them. The following study portraits this situation from the perspective of intercultural competence, in the context of one Latin American University, the University of Costa Rica (UCR). It explores the intercultural competence needs of exchange students, whose common ground is the UCR. The population considered in the study are regular students of the University of Costa Rica, who p…

Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands

2016

The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abun…

Detection of a synthetic sex steroid in the American crocodile (Crocodylus acutus): Evidence for a novel environmental androgen

2017

Endocrine-disrupting contaminants (EDC's) are well known to alter sexual differentiation among vertebrates via estrogenic effects during development, particularly in organisms characterized by temperature-dependent sex determination. However, substances producing androgenic effects typically lack potency when tested in laboratory settings and are virtually unstudied in field settings. Here, we assay levels of a synthetic androgen, 17a-methyltestosterone (MT), in a heavily male-biased population of American crocodiles in the Tempisque River Basin of Costa Rica based on the recent hypothesis that this chemical is an EDC in developing crocodilian embryos. The presence of MT was documented in a…

Forearc carbon sink reduces long-term volatile recycling into the mantle

2019

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent…

Geosphere-biosphere interactions in bio-activity volcanic lakes: Evidences from Hule and Rìo Cuarto (Costa Rica)

2014

Hule and R ́ıo Cuarto are maar lakes located 11 and 18 km N of Poa ́s volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemica…

Influencia de las tecnologías de Información y comunicación en la motivación para el aprendizaje : el caso de los estudiantes universitarios del Inst…

2013

Luego de determinar que la influencia de las tecnologías de información y comunicación en la motivación en el aprendizaje de los estudiantes alcanza un 53%, otro de los logros de esta investigación ha sido el desarrollo de una escala de medición para la valoración de la motivación en el aprendizaje cuando se usan las TIC. Dicha escala fue sometida a criterios de fiabilidad y validez y los resultados de los cálculos para valorar esos criterios fueron muy satisfactorios. La creación de una herramienta de medición que satisfaga estos criterios de fiabilidad y validez tiene una importancia significativa porque puede ser considerada, seriamente, por investigadores que deseen realizar trabajos re…