Revisión bibliográfica sobre desarrollo y validación de un sistema automatizado para invernaderos

Abstract: In western Huila (Colombia) the agricultural sector in greenhouse crops shows a low use of technology. There is a need to develop jobs that allow farmers improve crop conditions in greenhouses, implementing new low–cost technologies that increase crop performance. The objective of this bibliographic revision is to establish the state of the art, in order to structure the project “Validation of an automatized greenhouse system to improve the tomato crop’s productivity in La Plata, Huila”. Scientific articles from specialized databases and technical documents were reviewed from state entities devoted to agricultural research were reviewed with the aim of learning about national and international research about the design, methodology and system development, control models and automatization applied to precision agriculture, production of tomato’s under cover crops in controlled environments and agroecologic conditions included  their respective cost and prices in the colombian market. The results of the review  show in detail the metodology, development platforms, electronic devices, variety of  selected tomatoes, type of greenhouse and watering systems that will be used for the  development of the project previously mentioned.Resumen: En el Occidente del Huila (Colombia) se evidencia baja utilización de tecnología por parte del sector agrícola en los cultivos manejados bajo invernadero; se hace necesario desarrollar trabajos que permitan al agricultor mejorar las condiciones de los  cultivos bajo cubierta, implementando nuevas tecnologías a menor costo que incrementen el rendimiento de sus cultivos. El objetivo de la presente revisión bibliográfica  es establecer el estado del arte, con el fin de estructurar el proyecto Validación de un sistema automatizado de invernadero para mejorar el rendimiento del cultivo de tomate  en La Plata, Huila. Se consultaron artículos científicos en bases de datos especializadas  y documentos técnicos de entidades estatales dedicadas a la investigación en temas agropecuarios, con el fin de conocer trabajos a nivel nacional e internacional realizados  sobre metodologías de diseño y desarrollo de sistemas, modelos de control y automatización aplicados en agricultura de precisión, producción de tomate bajo cubierta  en ambientes controlados y condiciones agroecológicas con sus respectivos costos y precios en el mercado colombiano. Los resultados de dicha revisión presentan, de  manera detallada, la metodología, plataformas de desarrollo, dispositivos electrónicos,  variedad de tomate seleccionado, tipo de invernadero y riego, datos que se utilizarán para el desarrollo del proyecto mencionado

Fish Ecology of the Alto Madre de Dios River Basin (Peru): Notes on Electrofishing Surveys, Elevation, Palm Swamp and Headwater Fishes

Our study analyzes the distribution of fish communities related to the environmental variables of the Alto Madre de Dios River, an Andean-Amazon watershed of southern Peru, between 300 and 2811 m a.s.l. within the Manu Biosphere Reserve. We provide new ecological and diversity data on fishes for these poorly studied rivers and new data for palm swamp habitats. With electric fishing techniques, we collected a total of 1934 fish specimens belonging to 78 species, 42 genera and 15 families. To assess main patterns of diversity we combined SIMPER and ANOSIM with canonical correspondence analysis to obtain an overview of the community structure of fish and their distribution related to aquatic habitats. Our results show an important shift on fish diversity at 700 m a.s.l. separating headwater and middle-lowland communities. Electrofishing was a hindrance due to the depth, flow and low conductivity of the rivers, but also allowed us to capture fish not observed with other techniques. We also compared the use of elevation with slope as an alternative variable for statistical analysis. Our results show that slope offers a solid and equivalent explanation for fish distribution variability, avoids redundance, and instead of giving geographical data offers ecologically solid information

A database of freshwater fish species of the Amazon Basin

The Amazon Basin is an unquestionable biodiversity hotspot, containing the highest freshwater biodiversity on earth and facing off a recent increase in anthropogenic threats. The current knowledge on the spatial distribution of the freshwater fish species is greatly deficient in this basin, preventing a comprehensive understanding of this hyper-diverse ecosystem as a whole. Filling this gap was the priority of a transnational collaborative project, i.e. the AmazonFish project - https://www.amazon-fish.com/. Relying on the outputs of this project, we provide the most complete fish species distribution records covering the whole Amazon drainage. The database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project. This database, delivered at both georeferenced localities (21,500 localities) and sub-drainages grains (144 units), represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation

Electrical signalling of dominance in a wild population of electric fish

Animals often use signals to communicate their dominance status and avoid the costs of combat. We investigated whether the frequency of the electric organ discharge (EOD) of the weakly electric fish, Sternarchorhynchus sp., signals the dominance status of individuals. We correlated EOD frequency with body size and found a strong positive relationship. We then performed a competition experiment in which we found that higher frequency individuals were dominant over lower frequency ones. Finally, we conducted an electrical playback experiment and found that subjects more readily approached and attacked the stimulus electrodes when they played low-frequency signals than high-frequency ones. We propose that EOD frequency communicates dominance status in this gymnotiform species

Exilio y migración forzada : tendencias latinoamericanas

La presente obra que lleva por título Exilio y migración forzada: tendencias latinoamericanas, presenta un panorama de la dinámica de los referidos temas en América Latina y el Caribe. Se trata de dos de las características políticas más relevantes en el escenario regional desde el siglo xix. Los textos que conforman el libro ofrecen un enfoque analítico de ambos fenómenos desde la política, la sociología y la economía con una visión latinoamericana y ponen el acento en determinados actores exiliados, desterrados y migrantes forzados de nuestra América.Trabajo realizado con el apoyo del Programa UNAM DGAPA-PAPIIT IG40011

Evaluating the influence of environmental variables on fish assemblages along Tropical Andes: considerations from ecology to conservation

The lack of knowledge about freshwater biodiversity in remote areas like montane Andean rivers is noticeable and hinder the development of efficient conservation plans for aquatic ecosystems. Habitat requirements of tropical Andean fishes have been poorly analysed, despite the relevance of these ecological features on the fish conservation strategies. The present study aimed to examine fish assemblages along the altitudinal gradient in tropical Andean rivers and their relationship to habitat features to detect the most relevant abiotic factors and their implication on conservation. This study was conducted on a regional scale, along six basins located in tropical Andes (500 to 2,692 m a.s.l.). We studied fish diversity and distribution and their habitats along these elevation gradients. We found 6,320 specimens from 53 genera. Our analysis for the six most common and widely distributed genera (Astroblepus, Brycon, Bryconamericus, Chaetostoma, Pimelodella and Trichomycterus) underlines the relevance of hydromorphological variables on fish community structure in the Andean montane rivers, whereas human alterations seem to be less significant. These findings could be useful for current management and conservation strategies considering present threats over tropical montane rivers