Application of nanofiltration for pool water treatment: Assessing reduction potential of disinfection by-products

Disinfection of water is mandatory for swimming pools. Most of them use Chlorine or its derivates for that purpose. When entering the pool bathers bring substances such as sweat, hairs and cosmetics that react with disinfectants and form disinfection by-products (DBPs) which are known to be harmful for human health. In order to avoid the formation of these undesirable products new technologies for pool water treatment must be developed or alternatively a control system of the DBPs in the pool. The most important DBPs and their precursors are organic. Nanofiltration (NF) comes up as a possible solution for the problem as it is capable of rejecting organic matter. A nanofiltration filtration plant was installed in an indoor pool in Germany. The existed pool water treatment included flocculation, powdered activated carbon adsorption and ultrafiltration. During this study a branch current was treated by the new NF plant. The nanofiltration plant treated 0.3% of the global recycle flow, meaning approximately 9.7m3/day. During 110 days the of dissolved organic carbon (DOC), trihalomethanes (THM), adsorbable organic halogens (AOX), Ions, UV-absorbance, electrical conductivity and pH were measured every day from different key positions of the water treatment process. This intensive analysis of the effects and behaviour of the nanofiltration plant in a real scale application and its subsequent interpretation were carried out and the obtained information can be relevant for future applications in swimming pool water treatment. The rejection of DOC by the membrane has been shown to be 84% ± 4% while THM and AOX were 70% ± 11% and 95% ± 2% respectively. Ion rejection ranged from 57% to 99% depending on charge and size. THM and AOX formation potentials before and after nanofiltration were also evaluated, showing a significant decrease in 78% and 93% respectively. Umu-tests were also carried out in order to assess possible genotoxicity effects of the pool water. All results obtained were negative in genotoxicity. Despite of the high rejections shown by nanofiltration no significant decrease of THM concentration in pool water was achieved. THM showed a positive correlation with DOC with time delay and high variability in its concentrations. AOX showed an increase after the activated carbon shutdown. But compared to previous research AOX was also reduced in a 49% by NF. During the study the membrane presented an increasing flow decline. By the end of the investigation losses of 17.5% from the initial permeate flow were observed. Nanofiltration has shown its potential as a suitable pool water treatment process. Later studies should further investigate the operational settings needed in order to provide further improvement of water quality, the development of more fouling and chemical resistant membranes and more suitable cleaning strategies

Participación ciudadana en los servicios públicos domiciliarios y sus mecanismos a la luz de la Constitución de 1991, de la ley 142 de 1994 y demás decretos concordantes

80 páginas incluye ilustraciones y diagramasLa participación ciudadana en la prestación de los servicios públicos domiciliarios es un tema de gran trascendencia para la vida comunitaria del país por una parte, en cuanto incide de manera sustancial en la calidad de vida de la población, ya que esta redunda en el bienestar, la vida y la salud de los colombianos; y por otra, dada la cobertura poblacional, en cuanto afecta las necesidades básicas de todos los usuarios, suscriptores y potenciales suscriptores de estos servicios. Dada la amplitud de este campo temático, la presente investigación tiene el siguiente objeto : Establecimiento de la participación ciudadana en los servicios públicos domiciliarios y sus mecanismos tanto individuales como comuntarios

Morfología de los estadios larvarios de una población Mediterránea del cangrejo alóctono, Dyspanopeus sayi (Decapoda: Brachyura: Panopeidae)

[EN] In this study the complete larval development (including four zoeal stages and a megalopa stage) of Dyspanopeus sayi is described and illustrated in detail based on larvae reared in the laboratory. Ovigerous females were collected in Alfacs Bay, Ebro Delta (NW Mediterranean) where the species was recently introduced. These larval stages were compared with others collected in the plankton from the same area, the larval stages described previously for this species and the larval stages of the two other Panopeidae that inhabit the Iberian Peninsula: Panopeus africanus and Rhithropanopeus harrisii. Differences were found in both zoeal and megalopal larval characters between D. sayi and the other two species, which could raise doubt about their placement in the same family.[ES] En este estudio se describe e ilustra en detalle el desarrollo larvario (4 estadios zoea y un estadio megalopa) de Dyspanopeus sayi , a partir de larvas cultivadas en el laboratorio. Las hembras ovígeras fueron capturadas en la Bahía de Alfacs (NO Mediterráneo), donde la especie ha sido recientemente introducida. Los estadios larvarios descritos han sido comparados con larvas del plancton capturadas en la misma zona, con descripciones previas de esta especie y con descripciones de los estadios larvarios de las otras dos especies de Panopeidae que habitan en la Península Ibérica: Panopeus africanus y Rhithropanopeus harrisii. Se han encontrado diferencias destacables en algunos caracteres de los estadios, zoea y megalopa, lo cual podría poner en duda la posición de estas especies dentro de la misma familia.This study was funded by the Spanish “Ministerio de Ciencia e Innovación, Plan Nacional I+D” and the European FEDER funds through project MEGALO - PADN (CGL2009-11225). The “Ministerio de Ciencia e Innovación” also supported a FPI PhD grant to EMH (BES-2010-033297); results here presented are part of her PhD thesis project. Financial support to GG (post-doctoral fellowship; INIA) was provided by the Ministry of Science and Research.Peer reviewe

Morphology of the larval stages of a Mediterranean population of the allochthonous Say’s mud crab, Dyspanopeus sayi (Decapoda: Brachyura: Panopeidae)

In this study the complete larval development (including four zoeal stages and a megalopa stage) of Dyspanopeus sayi is described and illustrated in detail based on larvae reared in the laboratory. Ovigerous females were collected in Alfacs Bay, Ebro Delta (NW Mediterranean) where the species was recently introduced. These larval stages were compared with others collected in the plankton from the same area, the larval stages described previously for this species and the larval stages of the two other Panopeidae that inhabit the Iberian Peninsula: Panopeus africanus and Rhithropanopeus harrisii. Differences were found in both zoeal and megalopal larval characters between D. sayi and the other two species, which could raise doubt about their placement in the same family

Comparison of the power of four statistics in repeated measures design in the absence of sphericity with and without serial autocorrelation

The present article examines the behaviour of four univariate statistics for analyzing data in a mixed repeated measures design, the procedures of Greenhouse and Geisser (1959), of Lecoutre (1991), of Hearne, Clark and Hatch (1983) and of Jones (1985), which differ in how they approach the absence of sphericity, assuming either arbitrary correlation or serial autocorrelation. These four approaches were compared with respect to empirical power in conditions of multivariate normality and absence of normality, and of different underlying structures of covariance. Overall, when the distribution is normal, Monte Carlo comparisons indicate that when the matrix is stationary autoregressive or structured non-stationary autoregressive, the Lecoutre and Hearne et al. statistics are more powerful, the former enjoying slightly higher empirical power, with no large differences between the two in either direction of the autocorrelation (positive and negative first-order serial correlation). For an arbitrary non-stationary matrix, the Hearne et al. procedure is considerably more powerful than the Lecoutre statistic when the deviation of the sphericity is slight and severe, both in the two directions of the autocorrelation (positive and negative first-order serial correlation) and when it is arbitrary (correlation=0). When the data are underlain by a non-normal distribution, the HCH procedure is that with the greatest empirical power when the serial correlation is positive, and the JN procedure when the serial correlation is negative whatever the underlying deviation matrix

Datos perdidos y propiedades psicométricas en los tests de personalidad

The aim of this study was to analyze the influence of missing values on the psychometric properties of personality tests. An applied approach was used, trying to simulate conditions similar to those found in the professional practice. Two simulation studies were designed, based on actual data from the administration of ESQUIZO-Q test, which assesses schizotypy. In the first study a large sample was used (N=3056), and in the second one a smaller sample (N=200) was analyzed. In both cases four levels of missing values, and eight procedures for handling missing values were simulated. The influence of these conditions on the estimates of Cronbach's α, the factor structure of the test, and the arrangement of test scores were analyzed. The results suggest that in the presence of low levels of missing values, even the simplest imputation methods offer appropriate solutions from a applied point of view. From a statistical perspective the Expectation-Maximization (EM) method is the one with a better overall performance in the different criteria handled. Also noteworthy is the poor performance of replacement procedures when using the value of the previous or posterior item in order to maintain the factor structure of the data.Se investigó la influencia que tienen los valores perdidos sobre las propiedades psicométricas de los tests de personalidad. Se ha utilizado un enfoque  aplicado, simulando situaciones que puedan tener relevancia cara a la práctica profesional.  Se diseñaron dos estudios de simulación a partir de datos reales obtenidos de la aplicación de la prueba ESQUIZO-Q que evalúa esquizotipia. En el primero de ellos se utilizó una muestra de 3056 personas y en el segundo una de 200; en ambos casos se emplearon cuatro niveles de pérdida de respuestas y ocho procedimientos de imputación de los valores perdidos.Se estudió su influencia sobre las estimaciones del coeficiente α de Cronbach, la estructura factorial de la prueba y la ordenación de las puntuaciones en el cuestionario. Los resultados apuntan a que en presencia de niveles bajos de valores perdidos, incluso los métodos más simples, ofrecen soluciones muy razonables desde el punto de vista práctico. Desde la perspectiva más estadística el procedimiento de Expectación-Maximización (EM) es el que presenta un mejor comportamiento global en los diferentes criterios manejados. Destaca también el  pobre comportamiento de los métodos de sustitución por el valor anterior o posterior de cara a mantener la estructura factorial de los datos

Perfil fisiológico del ciclista y factores determinantes del rendimiento en el ciclista de ruta

148 p

Diseño de una red lpwan para la implementación de medidores inteligentes en cantón San Cristóbal provincia de Galápagos

El cambio climático que el planeta ha sufrido en el último siglo, debido al impacto ambiental de las actividades humanas ha puesto en riesgo el frágil equilibrio de los ecosistemas alrededor de todo el planeta. Esto es especialmente peligroso en ecosistemas aislados, donde se ha desarrollado una flora y fauna única, las cuales no están preparadas para los rápidos cambios en los patrones ambientales que se han dado en las últimas décadas. En este contexto, el cuidado del Parque Nacional Galápagos, declarado un patrimonio natural de la humanidad es una prioridad tanto para organizaciones gubernamentales como para ONG. El presente proyecto nace como una solución a la problemática de la contaminación ambiental ocasionada por el uso de combustibles fósiles dentro de la capital de la provincia, el cual es mayormente utilizado en la generación de energía eléctrica para el uso doméstico y las actividades económicas de sus residentes. Se busca aplicar los conocimientos adquiridos en redes de telecomunicaciones para brindar herramientas que permitan monitorear el uso de la de energía eléctrica en el sector residencial por parte del usuario final, en tiempo real, mediante el diseño de una red de capa 2, capaz de interconectar diferentes medidores inteligentes con el data center de la central eléctrica, con el objetivo de brindar un servicio de consulta en tiempo real del consumo eléctrico para promover un consumo responsable, evitar el uso indebido y excesivo de la energía generada, y transparentar el proceso de facturación de energía al consumidor final, logrando de esta manera un ahorro energético y evitar la quema de combustibles fósiles en la central térmica de la isla.The climate change that the planet has suffered in the last century due to the environmental impact of human activities has put at risk the fragile balance of ecosystems around the entire planet. This is especially dangerous in isolated ecosystems, where unique flora and fauna have developed, unprepared for the rapid changes in environmental patterns that have occurred in recent decades. In this context, the care of the Galapagos National Park, declared a natural heritage of humanity, is a priority for both government organizations and NGOs. This project was born as a solution to the problem of environmental pollution caused by the use of fossil fuels within the capital of the province, which is mainly used in the generation of electrical energy for domestic use and the economic activities of its residents. It seeks to apply the knowledge acquired in telecommunications networks to provide tools that allow monitoring the use of electrical energy in the residential sector by the end user in real time through the design of a layer 2 network capable of interconnecting different smart meters with the data center of the power plant, with the aim of providing a real-time consultation service of electricity consumption to promote responsible consumption, avoid the improper and excessive use of the energy generated and make the energy billing process transparent to the consumer final, thus achieving energy savings and avoiding the burning of fossil fuels in the island's thermal power plant