vol. 10 núm. 1 (2019)

The study was conducted in Mijitayo river, which is located in Pasto municipality, in the south-west of Colombia. The general objective was to apply a methodology based in the ecosystems protection to define round river width and the more suitable species to its recovery, having as main element the life zones identification that are in the study area. With this purpose, some of the phytosociological characteristics were studied, among which are: height, coverage, density and relative frequency, which are useful to determine the Importance Value Index (IVI), fundamental parameter along with the drainage density and the area of the afferent basin.The following life zones were obtained in the study site: the lower montane dry forest (bs-MB), the humid montane forest (bh-M), the very montane forest (bmh-M) and the sub-Andean Paramo (p-SA) with an estimated round river width of 15, 25, 29 and 23 meters, respectively. Finally, the recommended species for recovery were Verbesina arbórea, followed by Fuchsia dependens and Bocconia Frutescens for bs-MB; Tibouchina mollis and Verbesina arbórea for bh-M; Baccharis latifolia followed by Maytenus prunifolia and Cavendishia bracteata for bmh-M and finally, Phyllanthus Salviifolius followed by Munnozia Sp for p-SA.

The objective of the present study was to identify the best sowing date for new experimental varieties of corn and also, to select the best corn genotypes. The work was carried out in the experimental field of the Instituto Tecnologico de Roque, Celaya, Gto., Mexico. The corn genetic material was provided by CIMMYT and evaluated for two sowing dates, June 25th (rainfed) and March 25th (irrigation) of 2016 and 2017, respectively. The following variables were measured: days at male and female flowering, plant height, cob height and yield. The study was conducted as a Latice experimental design with three replicates. Mean comparison was performed by Least Significant Difference (LSD). Statistically significant differences for treatments and sowing dates were detected. The best sowing date was March 27th, favoring a corn grain production of 12.4 t ha-1 (12%, moisture content basis), compared to the 11.1 t ha-1 yield for June 25th sowing date. In grain yield, the genotypes 9 (RS98TLW-5 B) and 6 (RS98TLW-2 B) were the best with recoveries of 13.0 and 14.0 t ha-1, respectively. 

Chromium is a heavy metal widely used at an industrial level and commonly discharged directly into water sources, which leads to their deterioration. Therefore, this research seeks to verify the removal of chromium exerted by physical, chemical and biological treatment in industrial wastewater, in order to determine which alternative is more sustainable.With this aim, three reactors with industrial wastewater from a company in the metal-mechanic sector were tested; Chromium removal was initially evaluated by primary sedimentation achieving 16% removals; subsequently, the effect carried out by chemical precipitation with aluminum sulfate and calcium oxide was verified. Finally, the bio-absorption capacity of the microalga Spirulina sp was evaluated using living and dead biomass within 24 and 96 hours. Results show that there are mechanisms with easy implementation to avoid direct dumping. It was also found that the chemical treatment reduces chromium to values lower than 0.1 mg/l, with removals of 99%, however, it generates more than 30% of sludge and does not help to separate the metal. With the use of biomass, removals of up to 96.5% were achieved in the first 24 hours and a final chromium value of 1.02 mg/l, with the advantage that this method generates less than 10% of sludge and allows the recovery of chromium for its later use. Therefore, the implementation of a physical-biological treatment is recommended, since it allows improving the sustainability of the process.

Generated by the overconsumption of sucrose, diabetes and obesity has led to consumption trends of products with low calorie natural sweeteners. Glycosides of Stevia are an alternative sweetener that has a sweetness 200-400 times greater than sucrose and also have zero calorie. These glycosides have been obtained with conventional extraction techniques that generate high energy consumption and negative environmental impact. This work identifies the most used green extraction techniques for obtaining the glycosides. Some of them like microwaves generate rapid heating due to electric and magnetic fields; ultrasound increases the area of mass transfer due to cavitation, solvents in supercritical conditions have better ability to extraction, and enzymes promote the availability of the analyte breaking the cellulose. Ultrasound presented higher yields with values of 96,46 and 36,92 (mg/g of extract) for stevioside and Rebaudioside-A, respectively. Some of the new extraction techniques based on high pressures and temperatures like the use of accelerated solvents extraction (with yields of up to 63,20 mg/g dry extract, for stevioside), are environmentally friendly technologies with the environment and they have potential industrial uses.

The global interest to know and deal with infectious diseases in humans and animals has led to the development of different models (mathematical, stochastic, discrete), applied to predict the spread of new epidemics, reduce the spread of infectious diseases, evaluate the impact of different disease control strategies and improve the living conditions of individuals. Nowadays, new techniques and tools are being implemented to model infectious diseases, this paper describes the main concepts of this area, current trends and existing challenges, and finally, describes some criteria for the selection of an epidemiological model.

The Waste Electrical and Electronic Equipment - WEEE has become a new source of pollution to the point that approximately 40 to 50 million tons per year are disposed in landfills in developing countries. Those types of hazardous waste are considered of special risk to the environment and humans. Hence, this research analysed the behaviour of generation of hazardous waste in industrial, commercial and service sector in the Neiva city. The regional environmental authority supported this work to identify the hazardous waste generators in the city and a tool Data collection was designed.The processing of this information identified the waste types, quantity, handle and final disposition in the city. It found that, in 2013, WEEE was 133,396 kg/yr and just 25% of the companies whose generated it, consider WEEE like a hazardous waste. This study lay the foundation to another researches related to hazard wastes, allowing to create new mid-term opportunities related to sustainability, innovation and entrepreneurship at local level.

Colombia has 1044 protected natural areas, which are the main tool for the conservation of biodiversity and its ecosystem services. Therefore, the implementation of complementary strategies for the conservation of biological diversity in natural areas is a mechanism to guarantee the functionality of Colombian ecosystems. In the present article, a review was made about the establishment of international strategies known as RAMSAR sites, important areas for Bird Conservation, Shorebird Reserves, Biosphere Reserves and Natural Heritage Sites that have been recognized as interior of the protected natural areas of Colombia, this with the purpose of identifying and providing information on the current state of implementation of these conservation strategies in the National System of Protected Areas of Colombia.

The livestock activity is linked to processes with environmental repercussions. Methane (CH4) and nitrous oxide (N2O) are two important greenhouse gases (GHG) emitted into the atmosphere by livestock during the processes of enteric fermentation and excreta management, which contribute to global warming. The objective of this paper was to review the amount of GHG emitted (kg CO2e) per kg of product generated from the main ruminant species (sheep, goats, buffaloes and bovines) used in tropical areas, under grazing conditions. For small ruminants, according to previous researches, emission intensities (EI) for meat was between 25 - 49.5 kg CO2e and for milk was within 5.5 and 11.2 kg CO2e; for buffaloes, EI was among 2.5 – 5.8 kg CO2e / kg FPCM and 21 – 70 kg CO2e / kg CW; for meat cattle, EI was amid 21- 76 kg CO2e; and for dairy cattle, EI was betwixt 2 – 9 kg CO2e. The differences found between the regional averages and the data for the same area of a country, can be due to different factors such as the quality of the pastures, level of intensification of the systems and climatic conditions.

Caña Flecha (Gynerium saggittatum Aubl.) has become an economic and cultural perpetuation of ancient indigenous peoples of the north coast of Colombia. However, the ignorance of the behavior of this crop in diverse edaphoclimatic conditions, generates low production capacity. In the present work, the fiber and photosynthesis yields of 5 arrow cane genotypes under two levels of fertilization in ten localities of the department of Córdoba were analyzed: Bajo Grande, La Abisinia, San Martin, San Efrain, Tófeme, Buenos Aires, INTECAVI, Bella Cecilia, Chimalito and la Oportunidad, it was used a randomized complete block design with 5x2 factorial arrangement: five (5) genotypes (Criolla, Criolla 1, Criolla 2, Martinera y Costanera), subjected to two (2) fertilization levels without organic fertilization with three (3) replicates. The length of the central rib (LNC) and the rates of gaseous exchange net photosynthesis, internal concentration of CO2, stomatal conductance and transpiration were measured. Fiber yields were analyzed according to the method of Lin y Binns (1988) y Carneiro (1998). Duncan analysis of variance and comparing means at the α = 0.05 level were made according to the proposed design, using SAS 9.1 statistical package. There were higher rates of photosynthesis and fiber yields in the Criolla and Criolla 1 genotypes compared to the rest, as well as a better development of the plants in the localities of Buenos Aires, Bella Cecilia and Chimalito. More stable fiber yields were obtained when organic fertilization was applied. The results suggest to encourage the establishment of Criolla and Criolla 1 genotypes in the localities of Buenos Aires, Bella Cecilia and Chimalito, under the application of organic fertilizers that improve his productivity and avoid the depletion of the soils.

Los sistemas de publicaciones han tomado parte de los principios estadísticos descriptivos para poder evidenciar la importancia de sistemas de medición en las revistas, dentro de las que se destacan: tazas de rechazo, números de pares externos, estadísticas de rebote entre otros, sin embargo, el mayor reto de la mayoría de las revistas es la de propender a las buenas practicas editoriales y estas a su vez a mejorar los criterios de calidad con las que se disponen.

This study analyzes the relevance of the competences developed in undergraduate projects of the students within the Forest Engineering curriculum project at the Francisco Jose de Caldas District University, with respect to the professional profile adopted and approved by the Ministry of Education; hence, the undergraduate dissertation defenses approved between 2015 and 2017 developed by the students trained with the updated curriculum in 2009 to satisfy this career profile were compiled. The projects were classified by competence; for each evaluation criteria were defined, based on the common characteristics of the subjects covered by these projects, with four levels of development of each competence, which proceeded to make the qualification of the undergraduate projects. A total of 67 undergraduate projects with dissertation defense approved until 2017 were found as part of the new curriculum, whose 62 were granted access to develop the evaluation. There was no evidence of proportionality between the development of the demonstrated competences and the number of projects in each one. On the other hand, it was observed that most of the competences cover many subjects whereby they demonstrate generality but lose specificity, which in most cases evidences a very basic development of the skills of a forest engineer trained in the District University.

In the production of sugar from sugarcane, a byproduct called molasses is generated, which is used in the production of fuel alcohol this in turn generates a new residue called vinasse. On average, 10 to 15 liters of vinasse are generated by liter of alcohol produced. Vinasse has a high content of organic matter and micronutrients, which pollute the environment because of an inadequate handled. Within these minerals is potassium between 10 and 18 mg/ml, approximately, which limits the use of vinasse as a fertilizer due to the contamination of water sources and soil with this metal and restring its use as component in the formulations of animal food. In consequence, this paper presents the results of the reduction of potassium in distillation vinasses from a sugarmill from the region by a strong cation exchange resin and then, a sulphuric acid solution (4 %) was used as eluent for regenerate the exchange resin. A reduction between 97 – 98 % was obtained from the initial contain of potassium in the vinase and potassium recovery was 99 % as a potassium sulphate solution, which can be used again as liquid fertilizer. Decationized vinasse could be used as organic fertilizer in higher proportion in the sugarcane crops.