University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

Protected Areas and Conservation of Biodiversity in the Tropics

Abstract: We compared deforestation rates and the extent of fragmentation inside and outside protected ar- eas in the Sarapiqui region of Costa Rica. We determined deforestation rates using remotely sensed images with supervised classification. We georeferenced the processed images and then transformed them to vector format for final mapping and parameter quantification. The deforestation rate in protected areas was low and declined sharply from 0.56% annually between 1976 and 1986 to 0.16% from 1991 to 1995. Outside the protected areas, the rate decreased from 3.6% in 1976-1986 to 2.8% in 1986-1991, but it increased again to 3.2% in 1991-1995. Fragmentation outside the protected areas increased considerably: the number of patches increased from 537 in 1976 to 1231 in 1996, while during the same period the average size of patches de- creased from 0.95 to 0.25 km 2 . Forest landscapes in the Sarapiqui region are likely to lose considerable biodi- versity because of the past forest loss and fragmentation even without further increases in deforestation and fragmentation.

Motivación: perspectivas teóricas y algunas consideraciones de su importancia en el ámbito educativo

Abstract: This article has for objective to review the concept of motivation, its historical development, and the three main approaches about it: behavioral, cognitive and humanistic, and some important aspects of the motivation on the educational ambit. The first approach emphasizes that people are motivated by the profit or reward they can receive. The humanistic underlines the qualities of human beings, their ability to grow and their freedom of choice. This approach looks at the motivational theories: Hierarchy of Needs by Maslow, Existence, Relation and Growth Theory by Alderfer and McClelland's Theory of Needs. The cognitive approach points out that the thought we think might happen determines what happens. Thoughts guide motivation. From this approach we review the Expectations Theory of Vroom, the Equity Theory Adams and the Model Setting Goals and Objectives from Trechera. Especially in the field of education examines the relationship between emotion and motivation, and the relationship between the Theory of Attributions and academic performance. Are some reasons that can guide student behavior and finally explores the intrinsic and extrinsic motivation and its influence in the academic performance of the students.

Vocal dialects, sex-biased dispersal, and microsatellite population structure in the parrot Amazona auropalliata.

Abstract: Geographic variation in microsatellite allele frequencies was assessed at nine sites in two regional vocal dialects of the parrot Amazona auropalliata (yellow-naped amazon) to test for correspondence between dialects and population structure. There was no relationship between the genetic distances between individuals and their dialect membership. High rates of gene flow were estimated between vocal dialects based on genetic differentiation. In addition, 5.5% of pairs of individuals compared across the dialect boundary were estimated to be related at the level of half siblings, indicating that dispersal is ongoing. The number of effective migrants per generation between dialects estimated with the microsatellite data was roughly one-seventh the number estimated with mitochondrial control region sequence data from the same individuals, suggesting that gene flow may be female-biased. Together, these results suggest that the observed mosaic pattern of geographic variation in vocalizations is maintained by learning of local call types by immigrant birds after dispersal. We found no evidence that ongoing habitat fragmentation has contributed to cryptic population structure.

Energy budget analysis for Poás crater lake: implications for predicting volcanic activity

Abstract: AWORKING model for many active stratovolcanoes involves a magma column with a frozen cap, cooled by a meteoric-water hydrothermal system. Systems with such high latent and specific heat capacities may easily buffer internal temperatures and apparent surface activity during short-term changes in power output. The surface manifestation of volcanic hydrothermal systems takes the form of boiling mud pools, hot springs, fumaroles, and in about 20–30 cases worldwide, hot crater lakes1–7. The latter are rare because they require special conditions to exist: high water supply, confined fumarole discharge, low permeability substratum and effective sub-surface heat transport. Crater lakes at active volcanoes are in a state of dynamic equilibrium whereby annual water losses through evaporation and infiltration are balanced by additions due to, for example, rainfall and runoff. Any change in volcano power output will directly affect the internal energy and surface heat loss of the lake. Vaporization of water within the hydrothermal system, leading to enhanced steam discharge from fumaroles, can also absorb increased power output. For long-term (months to years) power changes, we propose that crater-lake and fumarole discharge variations may well occur before significant signals on seismic and tilt networks are detected. As an illustration of these ideas, we consider here the recent activity at Poas volcano, Costa Rica.

Latin American Study of Nutrition and Health (ELANS): rationale and study design

Abstract: Obesity is growing at an alarming rate in Latin America. Lifestyle behaviours such as physical activity and dietary intake have been largely associated with obesity in many countries; however studies that combine nutrition and physical activity assessment in representative samples of Latin American countries are lacking. The aim of this study is to present the design rationale of the Latin American Study of Nutrition and Health/Estudio Latinoamericano de Nutricion y Salud (ELANS) with a particular focus on its quality control procedures and recruitment processes.