Scielo RSS http://www.scielo.sa.cr/rss.php?pid=0379-398220160005&lang=es vol. 29 num. lang. es http://www.scielo.sa.cr/img/en/fbpelogp.gif http://www.scielo.sa.cr http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500003&lng=es&nrm=iso&tlng=es Abstract When discussing pedestrian bridges, it is always useful to consider the latest work done in Colombia. These innovative constructions not only make it possible to cross rivers and roads, but also show how competitive this material is in ecological engineering. The spread of this type of construction throughout the country indicates that Guadua bamboo is already a part of Colombian culture, and that its fresh style is no longer associated only with poverty and social improvement projects. Furthermore, it shows that this material is a perfectly feasible option for a country such as ours, which is exposed to landslides, flooding and earthquakes. Although pedestrian bridges were initially built to shorten distances and overcome natural barriers, during the last several decades they have also become necessary to safeguard pedestrians who have to walk in areas of very high urban growth. However, in spite of the existence of alternative solutions to the same problem, almost all such solutions are postponed, in that they normally involve a State investment. This article addresses a construction technique which originated in South American indigenous populations. Although it was forgotten by several generations, this technique, which has been updated, has multiple benefits. By injecting concrete in bamboo internodes it is possible to build structures that are in harmony with current needs, as well as bridges with more lighting Most importantly, this makes low-impact construction accessible to small communities or private businesses with limited resources. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500014&lng=es&nrm=iso&tlng=es Abstract The current state of water resource management and planning in Latin American and Caribbean countries is described and discussed. The analysis is based on the most recent studies on this subject, which provide elements such as updated and duly verified information on the legislative, institutional and organizational reality in the countries of the region. Integrated planning and management of water resources has been characterized by a great diversity of legal and institutional approaches, including long debates on water bills and constant proposals to amend the few water laws in force (Dourojeanni & Jouravlev, 2002.) Some countries such as Mexico and Chile have been more successful in achieving important goals. However, Continuity in time and appropriate coverage are still required, as they are both lacking for now. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500033&lng=es&nrm=iso&tlng=es Abstract This document presents results of research in which an autochthonous consortium of cyanidedegrading microorganisms was developed for use in the biological treatment of hazardous cyanide waste. These autochthonous microorganisms were lyophilized (freeze dried) in different protective media, such as gelatin and lactose broth, at different temperatures (-35,-45,-55 and -65 oC). The preliminary treatment of cyanide wastes involved pretreatment of sludge for 3-5 days to leach the waste, and a subsequent treatment in aerated lagoons, where the consortium of lyophilized microorganisms was applied. Eight different lyophilized samples were obtained at different temperatures using two protective media for lyophilization, which produced excellent results six months after lyophilization. The consortium of lyophilized microorganisms showed 70% to 80% viability, with cyanide extraction percentages higher than 95%, and can be kept active for long periods of time (for years). Lyophilized microorganisms can be used for biodegradation of cyanide wastes from gold mines or from any other cyanide waste such as that from metallic electroplating baths, or from the jewelry manufacturing industry. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500047&lng=es&nrm=iso&tlng=es Abstract Biodigesters are designed to optimize biogas production using organic wastes, thereby attaining clean, low-cost renewable energy. In 2008, a group of ITCR researchers worked on developing a wireless electronic system for control and protection of biogas production. One of the specific objectives of this work was to find information about methods to increase biogas production. In this review we established the mathematical parameters related to biogas estimation of productivity. We then focused on the influence of chemical factors such as substrate composition, substrate combinations, addition of fat, and presence of inhibitors. We also studied the effect of physical factors such as temperature, solids removal, protein exclusion and phase separation during anaerobic digestion of organic matter. Finally we attempted to determine the role of biological factors such as the addition of thermophilic bacteria and the importance of methanogens. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500054&lng=es&nrm=iso&tlng=es Abstract In the last decade, the adoption of Genetically Modified Crops (GMC) has increased in scale worldwide. The total area planted with biotechnological crops reached 365 million acres in 2010, while the number of farmers around the world who decided to produce crops with this technology increased as well. At a regional level there have been different responses from government agencies, which have formulated rules and regulations in keeping with the realities of these countries. In Central America, the countries that are most involved in the development and cultivation of food biotechnology techniques are Guatemala (papaya), Honduras (beans and maize), and Costa Rica (cotton, soybean and pineapple). At a global level, the latter two were among the 29 countries with the most GMO crops in 2010. Some countries of the region have also implemented governmental regulatory structures through technical committees on Biosafety. The most important characteristics of these crops in terms of trade continue to be the provision of herbicide tolerance or pest resistance. However, the introduction of new modified products with good prospects in the market is also noteworthy. These experiences with cultivation and Biosafety regulation at a regional level could lead to successful and progressive development of agricultural and food biotechnologies in the near future. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500070&lng=es&nrm=iso&tlng=es Abstract Sustainable development is based on ethical principles such as respect for and harmony with nature, political values such as participative democracy and social equity, and moral norms such as environmental rationality. Sustainable development is egalitarian, neutral, and self-managed, able to satisfy the basic needs of people, respecting cultural diversity, and improving the quality of life. The concepts of agriculture and sustainable development refer to the need of minimizing degradation of fertile land, while working to increase production. They include agricultural activities such as soil and water management, crop management, and the conservation of biodiversity, taking into account the provision of food and raw materials. Sustainability of agricultural production systems refers to the capacity of the system to maintain its productivity in spite of economic and natural, external or internal limitations. Sustainability is a function of the natural features of a system and the pressures and interventions it experiences, as well as social, economic, and technical interventions that are carried out in order to fight negative pressures, highlighting the resiliency of the system. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500086&lng=es&nrm=iso&tlng=es Abstract A review was carried out of the physical and chemical properties of flours and starches made from cassava, yam, ñampi, and sweet potatoes. Amyloseamylopectin content, viscosity, nutritional value and fiber content were studied to associate them with their functional and technicalfunctional properties. A relationship was found between amylose-amylopectin, viscosity and fiber content and digestibility of those starches, as well as with glycemic index values. It was found that it is possible to introduce modifications through fermentation to enhance the nutritional value of these starches. Fermentation allows the production of gluten-free bread and energy drinks as an option to diversify products. It was also found that there is a relationship between starch viscosity and a reduction of fat absorption in fried foods. http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0379-39822016000500095&lng=es&nrm=iso&tlng=es Abstract [11] This investigation, “HidroEsta, software for Hydrological Calculations” is oriented towards the creation of a computing tool using Visual Basic intended to facilitate and simplify difficult calculations that must be carried out in hydrological studies. [12] The software allows making calculations of statistical parameters, as well as linear and nonlinear, simple and multiple regression calculations, and polynomial regressions. It is also useful for evaluating if a series of data can be fitted to a series of distributions, and calculating design events with a given probability of occurrence, based on a seasonal variation curve or a duration curve; analyzing a storm and calculating maximum intensities based on pluviograms data; calculating flow measurements taken with windmills or current meters; calculating maximum flows with empirical and statistical methods; calculating evapotranspiration and hydric balance. [13] Several numeric methods were used to solve the equations, selecting the most appropriate one for each case. The results of this work provide civil, agricultural engineers, and agronomists, hydrologists and other specialists who work in this field with a tool that enableZs them to carry out calculations, rapid simulations, and determine flow or precipitation for designs.