Search

This paper presents a research study about timber shear walls, with materials commercially available in Costa Rica. With new developments in engineered timber, the Costa Rican Seismic Code included a chapter on timber structures, defining diaphragms and shear walls as part of the lateral resisting system. A research study was then carried out, with the objective of determining the structural behavior of a typical shear wall. Twelve specimens were constructed and tested, varying the nail spacing and anchorage system. The specimens were tested with monotonic and cyclic loading procedures according to ASTM E564 and ASTM E2126 respectively. It was found that the specimens can develop an adequate shear strength and stiffness if the end studs are adequately anchored to the foundation. These results are an important input for the Costa Rican Seismic Code and for the development of engineered timber in Costa Rica. [ABSTRACT FROM AUTHOR]

Energy policies influence the production and living costs of firms and households in a country. New policies require investment and implementation effort. However, not all policy options have equal outcomes and can contribute differently to a country's development. This paper presents a framework to assess how an individual policy performs under economic and environmental criteria -costs and greenhouse gas emissions- and Sustainable Development Goal advancement. The assessment allows comparing policies with a long-term perspective and is applied to Costa Rica. We found that transport sector measures that reduce transport intensity -transport demand per unit of GDP- have the highest benefits and SDG advancement, e.g., modal shift to public transport and passenger rail. However, penetration of zero-emission vehicles (ZEV) in private and freight transport will be necessary to reduce emissions considerably. [ABSTRACT FROM AUTHOR]

Fuel demand during the last 50 years in Costa Rica has increased constantly. Do the price of fuels and Gross National Income contribute to explain these trends? This paper explores the existence of causal relations between economic growth, fuel price, and transport demand (represented by fuel consumption and registered vehicles). Vector autoregression (VAR) models were estimated with a time series of data of 1965-2019. Causal relations were found between fuel demand and income, but not with registered vehicles. The effect of price on demand and income were documented, which is important for policy formulation (in particular, possible taxation of fuel demand as a carbon mitigation strategy). [ABSTRACT FROM AUTHOR]

Objective. To summarize the results of research conducted in Costa Rica in which mathematical and statistical methods were implemented to study the transmission dynamics of mosquito-borne diseases. Methods. Three articles with mathematical and statistical analysis on vector-borne diseases in Costa Rica were selected and reviewed. These papers show the value and relevance of using different quantitative methods to understand disease dynamics and support decision-making. Results. The results of these investigations: 1) show the impact on dengue case reports when a second pathogen emerges, such as chikungunya; 2) recover key parameters in Zika dynamics using Bayesian inference; and 3) show the use of machine learning algorithms and climatic variables to forecast the dengue relative risk in five different locations. Conclusions. Mathematical and statistical modeling enables the description of mosquito-borne disease transmission dynamics, providing quantitative information to support prevention/control methods and resource allocation planning. [ABSTRACT FROM AUTHOR]

Problems in transit fare equity affect the daily commute of specific groups that depend mostly on public transportation. Previous studies showed that some routes present operational characteristics that increased the price charged to the users. To address this issue, a methodology to identify the routes that have fares much higher than expected, after considering operational parameters, is developed. This paper presents a methodology implemented to evaluate fare inequities in public transport networks. The case study is the bus public transport network in Costa Rica. The evaluation is performed using fare per kilometer as independent variable and operational variables, such as route length, monthly ridership and vehicle occupancy by using cluster analysis and Bayesian multilevel modelling. The results indicate that random coefficients models perform better than independent models for clustered data. Furthermore, the routes with higher differences between observed and estimated (i.e., expected) fares are the ones to be addressed first in individual audits, because these are the routes who charge higher operational costs into the fare, increasing inequity among the population. [ABSTRACT FROM AUTHOR]

A precise orthometric height (H) and orthometric height difference (ΔH) determination is required in many fields like Construction, Geodesy and Geophysics. H is often obtained from an ellipsoidal height (h) and geoid height (N) of a geopotential model (GM) because this computation does not have the spirit leveling restrictions on long distances. However, the H accuracy depends on the GM local area adaptation, and current global geopotential models (GGMs) have not been yet evaluated for Costa Rica. Therefore, this paper aims to determine which GGM maintains a better fit with a GPS/levelling baseline that contains the gravity full spectrum. A 74 km baseline was measured using GPS, spirit leveling and gravity measurements to validate the N computed from EGM2008, EIGEN-6C4, GECO, EGM96, GGM05C and GOCO05C. First, an absolute N assessment was made, where geoid height from the GGMs (NGGM) were directly compared to the geometric geoid heights (Ngeo) obtained from GPS and spirit levelling. A bias fit (Nbias) was computed from this comparison to the GGMs with respect to the local vertical reference surface (W0). This Nbias value differs from model to model but the best fit is given by GECO. By subtracting the Nbias, a relative geoid height (ΔN) assessment was designed to compare the differences between GGM relative geoid height (ΔNGGM) and geometric relative geoid height (ΔNgeo) on segments along the baseline. The ΔN comparison shows that EGM2008, EIGEN-6C4 and GECO better represent the Costa Rican Central Pacific Coastal Zone and over long distances, ΔH can be computed with a decimeter to centimeter precision. [ABSTRACT FROM AUTHOR]

This document presents the results of a process of technical review of nearly 60 records of environmental impact assessment (EIA) carried out in recent years as part of the course of Environmental Geology I. The main problems detected and most common indicated in most records. This concludes that there are serious problems in implementing existing procedures and current technical tools, by both environmental consultants and the “Secretaría Técnica Nacional Ambiental” (SETENA). To this situation, the environmental management consultant geologist is not the exception, reason why it is necessary that the above mentioned professionals are aware of the severe legal consequences involved. Finally, this paper proposes five key solutions to correct and improve the serious efficiency problem of the EIA system, which has brought the country to a condition of unsustainable development. [ABSTRACT FROM AUTHOR]

This paper introduces Titan2D, a depth averaged model of an incompressible Coulomb continuum for "shallow water" granular flows. Titan2D has been used successfully at many volcanoes to predict inundation by block-and-ash flows and debris avalanches. It can be run as a stand-alone program or through Vhub, a cyber-infrastructure platform. Practical considerations of choosing appropriate user inputs and the basics of running the model are discussed herein. Both synthetic and natural terrain examples are presented, including simulations of a block-and-ash flow generated from the gravitational collapse of a synthetic dome at Turrialba volcano (Costa Rica). These results suggest that the model should be limited to simulate cases of dense volcanic granular flows, like those produced by gravity-driven dome collapse events, but cannot be used to simulate dilute pyroclastic density currents. Finally, estimation of the Ti-tan2D resistance terms by using empirical relationships provides a good method for reducing model input uncertainties. [ABSTRACT FROM AUTHOR]

The growth of Vochysia guatemalensis in Ultisols and Inceptisols of the Northern Huetar Region of Costa Rica were evaluated. This paper introduces the conditions of the sites, in the region under study where the species is growing. Making use of physical and chemical soil variables, it tries to explain the behavior of the site index (Is) and its relationship with those edaphic variables that show some kind of relation with this indicator of the quality of the land. In addition, working at 2 depths, the factors of the soil which limit or favor the growth of this species are determined, in order to identify the most appropriate, as well as the most inadequate, sites for the species. At to 20 cm depth, the best sites (IS greater than 23), are related to low pH, low calcium concentrations and median concentrations of magnesium, medium sum of bases and medium effective cation exchange capacity, an extractable medium acidity and medium saturation acidity. From 20 to 40 cm, it is observed that the best sites are associated with low apparent density, a high content of clay and iron, and a good amount of organic matter. The soils that show the best chemical condition are those associated with the worst quality of site (IS lesser than 20) for V. guatemalensis. This highlights the low nutritional requirements of this species, V. guatemalensis, which can be considered as adapted to relatively acidic soils of low fertility. [ABSTRACT FROM AUTHOR]

The aim of this paper is to describe a fragment of left mandible of a juvenile specimen of Pliometanastes. That found brings some light about the phyletic relations among Pliometanastes protistus Hirschfeld & Webb, 1968 and ?Pliometanastes galushai Hirschfeld & Webb, 1968, and strongly suggests that Pliometanastes is a monospecific genus. [ABSTRACT FROM AUTHOR]

An integrated approximation of the impact of volcanic eruptions in the period between the years 1953 and 2005 in Costa Rica is presented for the first time. The detail-led damage (bridges, houses, railways, factories), economic losses (agriculture, livestock, drinking water), disruption of activities, loss of life and investments (donations, mitigation measurements), is given. This focuses on the disasters and economic effects, but the sociological and psychological effects were not assessed. Two national emergencies occurred with the eruption of Irazú in 1963-1965 and Arenal in 1968, and several volcanic crises occurred at other volcanoes including Poás (1953-1955, 1989-1994), Rincón de la Vieja (1967, 1991, 1995 and 1998), and again in Arenal (1975, 1988 and 2000), which produced economic losses due acid rain and/or lahars, and loss of life resulting from pyroclastic flows. Volcanic activity is responsible for a loss of at least $48.7 million in the last century, quantity that is necessary scalar in a future study. In this century, the damage due acid rain is more than $200 million. It is certain that 103 people were killed by volcanic activity in the 20th century, and there are no additional reports of deaths or injuries since 1700. This paper is the basis for future work focused on the socio-economic evaluation, risk analyses and future projections. If a new eruption similar to those of Irazú in 1963-1965 or Arenal in 1968 were to happen during the present century, the economic losses can be expected to be larger than previous ones. [ABSTRACT FROM AUTHOR]