Se evaluo el efecto de la luz ultravioleta sobre la poblacion de coliformes fecales presentes en agua. Para la calibracion del equipo se realizaron pruebas con muestras de agua previamente contaminadas obteniendose concentraciones conocidas. Con los resultados se construyeron curvas de calibracion donde se relaciono la dosis aplicada y la poblacion de coliformes fecales presente en el agua luego de ser expuesta a la luz ultravioleta. Posteriormente se tomaron muestras de agua en tres estaciones del rio Chillan, en los puentes El Saque, Nebuco y Vista Bella. La concentracion de coliformes vario en cada estacion, siendo el punto de mayor concentracion el puente Vista Bella, luego le sigue Nebuco y finalmente El Saque. Cada muestra se dividio para la aplicacion de tres dosis de luz ultravioleta 0,155, 0,224, 0,376 J cm-2. Al aumentar la dosis aplicada, la poblacion de coliformes fecales disminuye, sin embargo la diferencia entre tratamientos no es estadisticamente significativa. En consecuencia la mejor dosis para la desinfeccion de aguas usadas para el riego de frutas y hortalizas que crecen a ras de suelo es de 0,155 J cm-2

En Cuba el cultivo protegido constituye una tecnología promisoria para extender los calendarios de cosechas de las hortalizas. Estas condiciones favorables también lo son para el desarrollo de los nematodos del género Meloidogyne. Numerosas alternativas se emplean para la reducción de esta plaga. En la agricultura se han realizado estudios de la utilización del riego con agua tratada magnéticamente, con el propósito de lograr mayores rendimientos en los cultivos. La investigación se realizó con el objetivo de evaluar el efecto que ejerce el agua tratada con campo magnético estático con inducciones entre 005 y 007 Tesla sobre Meloidogyne spp. en el cultivo del pepino (Cucumis sativus), se utilizaron los híbridos HA 454 y HA 436 en la campaña de primavera del 2008 bajo condiciones de Cultivo Protegido, en la Unidad Hortícola de Campo Antena en Santiago de Cuba. Los resultados de la investigación arrojaron que Meloidogyne spp afectó más al área sin magnetismo que la tratada con inducción magnética, con diferencias significativas entre tratamientos, alcanzando medias de 3.25 y 3.00 en el testigo y medias de 2.00 y 1.50 en el área tratada, logrando además, mayor longitud de la guía, de la raíz y mejor calidad de los frutos, incrementándose los rendimientos. El uso de esta tecnología resulta una alternativa positiva en el manejo de los nematodos en cultivo protegido, al permitir mejor, asimilación de los nutrientes promoviendo mayor tolerancia a la planta de las plagas y enfermedades contribuyendo a la protección del medio ambiente. | In Cuba the greenhouse constitutes a technology in order to extend the calendars of crops of the vegetables. The favourable conditions that this system of cultivation offers to the plantations also are it for the development of the nematodes of the Meloidogyne genus. Numerous alternating they are employed for the reduction of the levels of infection of this pest, in our country the utilization of the watering with water tried magnetically has reached great repercussion in the agriculture, there is been carrying out numerous studies with the purpose of improve of crop yield. The investigation was carried out with the objective of evaluating the effect that exercises the water had dealings with magnetic static field with inductions between 005-007 Tesla on Meloidogyne spp. in cucumber (Cucumis sativus) crop in conditions of greenhouse, in the Horticultural Unit of Field Antenna in Santiago from Cuba. The experiment was carried out there in the spring of the 2008 with the hybrid it Is HA 454 and there it Is HA 436. The outputs of the investigation reported that Melodogyne spp affected more to the area without magnetism that she had dealings with magnetic induction, achieving greater longitude of the guide, diameter of the shaft, and quality of the fruits, incrementing of yield. The use of this technology results a positive alternative in the control of nematodes in greenhouses, upon permitting better, assimilation of nutritious promoting greater tolerance of the plant to the pest and diseases and contributing to the protection of the environment.

The optimum temperature and exposure time necessary to obtain Probit 9(99.9968 % mortality) for third instar larvae of Anastrepha striata Schiner, when these are immersed in hot water, determined. Treatments were 39.0, 39.6 and 40.0 deg C for periods of 30 to 180 minutes at intervals of 30 min and 42.0 deg C for periods of 30 to 60 minutes at intervals of 10 min. The immersion times estimated to obtain Probit 9 were 154' 53", 137' 50", 124' 41" and 48' 00", respectively. The temperatures estimated to obtain Probit 9 from treatments for 90 and 120 min, were 41.53 and 39.67 deg C, respectively. These results allow to predict the feasibility of applying a quarantine heat treatment for fruits infested with A. striata, as well as to select the time and temperature most appropriate to treat sensitive fruits. | Se determino la temperatura y tiempo optimo de exposicion para obtener la Probita 9 (99.9968 % de mortalidad) para larvas de tercer instar de Anastrepha striata Schiner cuando se sumergen en forma directa en agua caliente. Los tratamientos fueron 39.0, 39.6 y 40.0 grados C por periodos de 30 a 180 minutos en intervalos de 30 min, y 42.0 grados C por periodos de 30 a 60 minutos en intervalos de 10 min. Los tiempos estimados para obtener la Probita 9 fueron 154' 53", 137' 50", 124' 41" y 48' 00", respectivamente. El analisis de los datos de mortalidad obtenidos con los tratamientos con duracion de 90 y 120 minutos estimo temperaturas de 41.53 y 39.67 grados C, respectivamente. Estos resultados permiten predecir la factibilidad de aplicar un tratamiento termico cuarentenario para frutos infestados por A. striata y ademas permiten elegir la dosis de tiempo y temperatura mas adecuada para frutos sensibles.

This work presents analysis of groundwater flow conditions and groundwater control measures for Vazante underground mine located in the state of Minas Gerais, Brazil. According to field observations, groundwater flow processes in this mine are highly influenced by the presence of karst features located in the near-surface terrain next to Santa Catarina River. The karstic features, such as caves, sinkholes, dolines and conduits, have direct contact with the aquifer and tend to increase water flow into the mine. These effects are more acute in areas under the influence of groundwater-level drawdown by pumping. Numerical analyses of this condition were carried out using the computer program FEFLOW. This program represents karstic features as one-dimensional discrete flow conduits inside a three-dimensional finite element structure representing the geologic medium following a combined discrete-continuum approach for representing the karst system. These features create preferential flow paths between the river and mine; their incorporation into the model is able to more realistically represent the hydrogeological environment of the mine surroundings. In order to mitigate the water-inflow problems, impermeabilization of the river through construction of a reinforced concrete channel was incorporated in the developed hydrogeological model. Different scenarios for channelization lengths for the most critical zones along the river were studied. Obtained results were able to compare effectiveness of different river channelization scenarios. It was also possible to determine whether the use of these impermeabilization measures would be able to reduce, in large part, the elevated costs of pumping inside the mine.

The impact of groundwater withdrawals on the interaction between multi-layered aquifers with different water qualities in the Viterbo geothermal area (central Italy) was studied. In this area, deep thermal waters are used to supply thermal spas and public pools. A shallow overlying aquifer carries cold and fresh water, used for irrigation and the local drinking-water supply. Starting with a conceptual hydrogeological model, two simplified numerical models were implemented: a steady-state flow model of the entire groundwater system, and a steady-state flow and heat transport model of a representative area, which included complex interactions between the aquifers. The impact of increased withdrawals associated with potential future development of the thermal aquifer must be considered in terms of the water temperature of the existing thermal sources. However, withdrawals from the shallow aquifer might also influence the discharge of thermal sources and quality of the water withdrawn from the shallow wells. The exploitation of the two aquifers is dependent on the hydraulic conductivity and thickness of the intervening aquitard, which maintains the delicate hydrogeological equilibrium. Effective methods to control this equilibrium include monitoring the vertical gradient between the two aquifers and the residual discharge of natural thermal springs.