Locating Multiple Leaks in Water Distribution Networks Combining Physically Based and Data-Driven Models and High-Performance Computing

Water utilities are urged to decrease their real water losses, not only to reduce costs but also to assure long-term sustainability. Hardware- and software-based techniques have been broadly used to locate leaks; within the latter, previous works that have used data-driven models mostly focused on single leaks. This paper presents a methodology to locate multiple leaks in water distribution networks employing pressure residuals. It consists of two phases: one is to produce training data for the data-driven model and cluster the nodes based on their leak-flow-rate-independent signatures using an adapted hierarchical agglomerative algorithm; the second is to locate the leaks using a top-down approach. To identify the leaking clusters and nodes, we employed a custom-built k-nearest neighbor (k-NN) algorithm that compares the test instances with the generated training data. This instance-to-instance comparison requires substantial computational resources for classification, which was overcome by the use of high-performance computing. The methodology was applied to a real network located in a European town, comprising 144 nodes and a total length of pipes of 24 km. Although its multiple inlets add redundancy to the network increasing the challenge of leak location, the method proved to obtain acceptable results to guide the field pinpointing activities. Nearly 70% of the areas determined by the clusters were identified with an accuracy of over 90% for leak flows above 3.0 L/s, and the leaking nodes were accurately detected over 50% of the time for leak flows above 4.0 L/

Modelamiento y control de velocidad de motor DC mediante algoritmo PID basado en reglas de Ziegler - Nichols

En la presente tesis de investigación se realiza el Modelamiento Matemático y el control de velocidad angular de un Motor DC mediante algoritmo P-I-D (proporcional-integral-derivativo) basado en las reglas de sintonización de Ziegler – Nichols. En el Modelamiento Matemático de un motor DC de armadura en tiempo continuo, se aplica la transformada de Laplace. La velocidad angular (RPM) de un disco acoplado en el eje del motor DC se mide con un sensor óptico, la cual se compara con la velocidad deseada (set-point), esta diferencia de error, es necesaria para que el controlador P-I-D ajuste la velocidad en la salida. Todo el sistema de control es de lazo cerrado. Previamente el controlador P-I-D, se implementó en un microcontrolador ATMega 328, se sintonizó con sus respectivos parámetros Kp, Ti y Td mediante el método de la última ganancia de Ziegler- Nichols. Simultáneamente, se realizó la simulación de los parámetros mediante la sintonización utilizando Matlab. Para lograr esto, se implementó un prototipo del sistema electrónico en una tarjeta de circuito impreso que contiene el sensor de pulsos, el motor DC, el ajuste del set-point y todo el circuito eléctrico necesario para comunicarse con el controlador P-I-D. El trabajo se desarrolla usando un modelo matemático analítico de primer orden valido para un motor DC de armadura y el análisis de sistemas de tiempo continuo.Tesi

Compromiso parental en estudiantes con necesidades educativas especiales en el contexto del aislamiento social en Chimbote 2020

La presente investigación titulada “Compromiso parental en estudiantes con necesidades educativas especiales en el contexto del aislamiento social en Chimbote 2020” tuvo como objetivo general conocer y describir el compromiso parental en los estudiantes con NEE en el contexto del aislamiento social generado por la pandemia del COVID–19. Esta investigación es de tipo básica, con un diseño descriptivo. Para este estudio, la población estuvo conformada por 371 padres de familia de los estudiantes con necesidades educativas especiales de los Centros de Educación Básica Especial de Chimbote, de los cuales se consideró a 230 como parte de la muestra. Para el recojo de la información se administró un cuestionario confiable (Alpha de Cronbach) y validado por expertos. Se concluyó que el nivel de compromiso parental en estudiantes con necesidades educativas especiales de los Centros de Educación Básica Especial de Chimbote en el contexto del aislamiento social es alto. Esto significa que, en la modalidad virtual, los padres de familia han adoptado de manera flexible su rol, tomando en consideración las necesidades evolutivas y educativas de sus hijos, así como los estándares que demanda la sociedad

Bile Salt Deconjugation by Three Strains of Lactobacillus Acidophilus and Characterization of Their Bile Salt Hydrolase

Food Scienc

Development of a prototype for submarine communications in shallow waters

The Telecommunications Marine Laboratory (TML) of the University of Cádiz takes part in a research project to study the intertidal sediments of the Bay of Cádiz. The collection of samples from the seabed and the transmission of data to the surface are performed by a Mini Profiler with four channels (MP4), which is supplied by UNISENSE. Each channel processes the samples collected by a single sensor. For power, control, and data transmission, a special wiring that connects the submerged subsystem with the surface subsystem is used. The tension transmitted by the cable to the MP4 structure makes its handling and positioning under water more difficult. This article explains the technological solution developed by the TML to replace some wiring from the MP4. For the prototype, two underwater acoustic modems have been used and an electronic system has been developed based on the Arduino platform, in order to multiplex, digitize, and transmit the data collected by the MP4 sensors, eliminating the need to use wiring. The submerged subsystem has an autonomous power supply by a battery.Peer Reviewe

Impacto de las acumulaciones de macroalgas en la comunidad biológica intermareal

Los efectos de la acumulación de macroalgas verdes en la comunidad biológica intermareal del caño Sancti Petri se siguieron a lo largo de un ciclo anual. La medida con microelectrodos selectivos de O2 y H2S permitió obtener perfiles detallados de la distribución vertical de estos parámetros. Los cambios en la microflora bentónica se estudiaron en la zona superficial del sedimento mediante microscopia óptica. Los cambios en la meiofauna se estudiaron tanto en la capa de macroalgas como en el interior del sedimento. La acumulación de macroalgas produce fenómenos de hipoxia/anoxia tanto en el sedimento como en el interior de la capa de macroalgas, que se acentúan en periodos de oscuridad, favoreciendo la acumulación de H2S en zonas cercanas a la superficie del sedimento. En estas condiciones se produce una reducción del 96.7% en la población de microalgas bentónicas y un cambio en la comunidad, pasando de estar dominada por diatomeas a estarlo por cianobacterias. La meiofauna incrementa su densidad de población en un 845 ± 535%. El grupo con mayor crecimiento fueron los nematodos, cuya población es 9 veces superior al control, pasando a dominar completamente la meiofauna con un 92 ± 1% del número total de individuos, lo que produce una gran reducción de la diversidad.Ministerio de Educacion y Ciencia, proyectos: REN2002-01281/MAR y CTM2006-04015Acciones Marie Curie: HPMF-CT-2000-0099

Cyanobacterial calcite cementation in a tidal channel of the Bay of Cadiz Natural Park

A study of the carbonated crust located in a tidal channel close to a hypersaline tidal lagoon of the Nature area of the Bay of Cádiz has been done. A textural, mineralogical, and an experimental study, including O2 y pH measurements have been conducted during a period of a month and a tidal cycle in four different locations along the channel. The results of the mineralogical and textural study and those from the microelectrodes, show how the photosynthetic activity of biofilms dominated by cyanobacteria and diatoms growing in the sediment surface seems to control the calcite precipitation on the intertidal sediments. Although bacterial remains are rarely preserved in beachrocks, this study shows how bacterial activity should be taken into account in beachrock development in coastal environmentsMinisterio de Educación y Ciencia, proyecto MICROBENTOS (CTM2006-04015/MAR

Microbenthic Net Metabolism Along Intertidal Gradients (Cadiz Bay, SW Spain): Spatio-Temporal Patterns and Environmental Factors

Microphytobenthos (MPB), the photosynthetic primary producing component of microbenthos, shows variable patterns in its biomass distribution along the intertidal gradient as a result of the interactions of factors such as light, tides, temperature, and grazing pressure. These patterns have been studied more extensively in northern European estuaries than southern European coastal systems. Even less information is available regarding temporal changes in MPB primary production rates in these systems. For this reason, we followed the seasonal changes in net production in light and dark respiration rates (determined by oxygen microelectrodes) and MPB biomass (estimated by sediment chlorophyll a) along the intertidal gradient of the inner Cadiz Bay during a year. Sediment cores were collected along two transects (five sampling stations per transect) with distinct sediment granulometry: one muddy [Puerto Real (PR)] and one muddy-sandy transect [San Fernando (SF)]. Our results show that MPB biomass and net production increased seawards reaching their maxima in winter. In contrast to what is observed in northern European systems, the higher solar irradiance and temperatures occurring in summer in southern Spain likely inhibit MPB production. In Cadiz Bay, spatial patterns of MPB biomass and net production depended on season and location due to the environmental heterogeneity observed. Environmental variables, analyzed by principal component analysis (PCA), were used to explain the variability of MPB metabolism by multiple regression. Selected principal component (PC) axes explained 60% of the net production in light and 41% of the dark respiration rates variability in PR, while they only accounted for 25% of the same rates in SF. The differences observed between transects and the variability in the environmental variables explaining them highlight the importance of considering the spatial heterogeneity of our system to estimate the contribution of MPB to the inner Cadiz Bay productivity. In our case, this contribution is significant accounting for up to 49% of the total benthic production of the inner Cadiz Bay intertidal sediments, confirming previous global estimates

Kinetics of Indigenous Nitrate Reducing Sulfide Oxidizing Activity in Microaerophilic Wastewater Biofilms

23 páginas.-- 10 figuras.-- 2 tablas.-- 74 referencias.-- Supporting Information: Dataset. in http://dx.doi.org/10.1371/journal.pone.0149096Nitrate decreases sulfide release in wastewater treatment plants (WWTP), but little is known on how it affects the microzonation and kinetics of related microbial processes within the biofilm. The effect of nitrate addition on these properties for sulfate reduction, sulfide oxidation, and oxygen respiration were studied with the use of microelectrodes in microaerophilic wastewater biofilms. Mass balance calaculations and community composition analysis were also performed. At basal WWTP conditions, the biofilm presented a double-layer system. The upper microaerophilic layer (~300 μm) showed low sulfide production (0.31 μmol cm-3 h-1) and oxygen consumption rates (0.01 μmol cm-3 h-1). The anoxic lower layer showed high sulfide production (2.7 μmol cm-3 h-1). Nitrate addition decreased net sulfide production rates, caused by an increase in sulfide oxidation rates (SOR) in the upper layer, rather than an inhibition of sulfate reducing bacteria (SRB). This suggests that the indigenous nitrate reducing-sulfide oxidizing bacteria (NR-SOB) were immediately activated by nitrate. The functional vertical structure of the biofilm changed to a triple-layer system, where the previously upper sulfide-producing layer in the absence of nitrate split into two new layers: 1) an upper sulfide-consuming layer, whose thickness is probably determined by the nitrate penetration depth within the biofilm, and 2) a middle layer producing sulfide at an even higher rate than in the absence of nitrate in some cases. Below these layers, the lower net sulfide-producing layer remained unaffected. Net SOR varied from 0.05 to 0.72 μmol cm-3 h-1 depending on nitrate and sulfate availability. Addition of low nitrate concentrations likely increased sulfate availability within the biofilm and resulted in an increase of both net sulfate reduction and net sulfide oxidation by overcoming sulfate diffusional limitation from the water phase and the strong coupling between SRB and NR-SOB syntrophic relationshipAC was funded by projects P06-RNM-01787, P11-RNM-7199, the PAI group RNM-214 from Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía and CTM2013-43857-R from the Spanish Ministry of Economy and Competitiveness. JMG was funded by the PAI group BIO-288 from Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

LA HIPERTRIGLICERIDEMIA EN LA ENFERMEDAD CORONARIA ¿ES UN FACTOR DE RIESGO?

La asociación entre hipertrigliceridemia y enfermedad arterial coronaria (EAC) es controvertida. Objetivo: establecer la  relación entre  el nivel  de triglicéridos  en pacientes con  enfermedad  coronaria, relacionar los valores elevados de triglicéridos con colesterol total, colesterol HDL, colesterol LDL,   sobrepeso   y obesidad en pacientes coronarios. Material  Y Métodos: Se evaluaron retrospectivamente pacientes  con y sin enfermedad coronaria demostrable que fueron asistidos en la consulta pública y privada  en la Cátedra de Medicina I Unidad Académica de Medicina Interna Nº 3 del Hospital Córdoba  y el Servicio de Cardiología de la Clínica Sucre de la ciudad de Córdoba, entre en 1 de enero y 31 de diciembre de 2009. Se consideró pacientes con enfermedad coronaria (casos) aquellos que tuvieron lesiones coronarias significativas las que mostraron una disminución de la luz arterial &gt;50% `por medio de cinecoronariografía. (15)(16) y un grupo control sin enfermedad coronaria objetivable. . Se incluyeron pacientes  entre 30 y 60 años de edad que tuvieran historia clínica completa. Resultados: El número total de pacientes incluidos fue de 100 casos,  64 casos en el grupo de  pacientes coronarios y  36 en los no coronarios. 74% de sexo  masculino, predominancia masculina en pacientes coronarios y femenina en no coronarios.  68%  era mayor de 50 años.  Los valores del lipidograma   no mostraron diferencias estadísticamente significativas en pacientes no coronarios y coronarios Los valores promedio  de TG fueron levemente más elevados en el grupo de no coronarios, aunque no mostraron diferencias estadísticamente significativas (p=0,7162). Conclusión: La hipertrigliceridemia no fue mayor en los pacientes coronarios y no se relacionó con  el índice de masa corporal, en pacientes con sobrepeso y obesos.  Summary: Hypercholesterolemia is a well known risk factor for  coronary cardiovascular disease (CVD). However, the role of triglycerides in CVD risk remains controversial. Objective: to study triglyceride level and its relationship with Cholesterol, HDL and LDL Cholesterol level, obesity and overweight in patients with and without CVD. Material and Methods: we retrospectively studied patients with and without CVD who attended to Córdoba Hospital  and Cardiology unit of Clínica Sucre  at Córdoba city between 1° January to 31 st of December of 2009. We included patients with age between 30 to 60 years old with CVD and a control group. Results: 100 patients were included, 64 with CVD and 36 as a control group. 74% were male and 68% older than 50 years old. Lipid values were not statistically significant in both groups. Triglyceride level was higher in the control group, although the difference was not statistically significant (p=0, 7162). Conclusion: Triglyceride level was not higher in patients with CVD. </pre