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Glutamate oxaloacetate transaminase 1 (GOT1) enzyme plays a critical role in the cell metabolism by participating in the carbohydrate and amino acid metabolism. In ischemic stroke, we have demonstrated that recombinant GOT1 acts as a novel neuroprotective treatment against the excess of extracellular glutamate that accumulates in the brain following ischemic stroke. In this study, we investigated the inhibitory effect of GOT1 on brain metabolism and on the ischemic damage in a rat model of ischemic stroke by means of a specific antibody developed against this enzyme. Inhibition of GOT1 caused higher brain glutamate and lactate levels and this response was associated with larger ischemic lesion. This study represents the first demonstration that the inhibition of the blood GOT1 activity leads to more severe ischemic damage and poorer outcome and supports the protective role of GOT1 against ischemic insults. [ABSTRACT FROM AUTHOR]

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One of the most important concerns within the field of urban hydraulic engineers is the right management of water resources. When there is more than one water source, there is a question that must be answered: How much water should be provided by each water source according to the demand curve of the network? This work proposes a methodology that solves this question. It involves an energy analysis of the water network based on the concept of the setpoint curve. The setpoint curve gives, for every supplied flow, the minimum head needed to satisfy pressure requirements in the network. In this sense, the setpoint curve of every source relates two variables: supplied flow and minimum required head. Energy consumption in every source is evaluated by means of the product of these two variables. Then flow distribution among sources is optimized and minimum heads are obtained from the setpoint curve. The optimization process has been validated in two different ways. On one hand, a discrete method has been used, where a predefined combination of flow distributions are evaluated. On the other hand, the solution is found by means of Hooke-Jeeves and Nelder-Mead optimization algorithms. To apply these methods EPANET and its Toolkit has been applied to the mathematical model of the network. The optimization process can be applied to networks models with and without leakages. Finally, the methodology is applied to two cases, one academic network and real network where maximum flow limitations of every sources were also taken into account. [ABSTRACT FROM AUTHOR]

The optimal sizing in water distribution networks (WDN) is of great interest because it allows the selection of alternative economical solutions that ensure design requirements at nodes (demands and pressure) and at lines (velocities). Among all the available design methodologies, this work analyzes those based on evolutionary algorithms (EAs). EAs are a combination of deterministic and random approaches, and the performance of the algorithm depends on the searching process. Each EA features specific parameters, and a proper calibration helps to reduce the randomness factor and improves the effectiveness of the search for minima. More specifically, the only common parameter to all techniques is the initial size of the random population ( P ). It is well known that population size should be large enough to guarantee the diversity of solutions and must grow with the number of decision variables. However, the larger the population size, the slower the convergence process. This work attempts to determine the population size that yields better solutions in less time. In order to get that, the work applies a method based on the concept of efficiency ( E ) of an algorithm. This efficiency relates the quality of the obtained solution with the computational effort that every EA requires to find the final design solution. This ratio E also represents an objective indicator to compare the performance of different algorithms applied to WDN optimization. The proposed methodology is applied to the pipe-sizing problem of three medium-sized benchmark networks, such as Hanoi, New York Tunnel and GoYang networks. Thus, from the currently available algorithms, this work includes evolutionary methodologies based on a Pseudo-Genetic Algorithm (PGA), Particle Swarm Optimization (PSO) and Harmony Search (HS). First, the different algorithm parameters for each network are calibrated. The values used for every EA are those that have been calculated in previous works. Secondly, specific parameters remain constant and the population size is modified. After more than 500,000 simulations, the influence of the population size is statistically analyzed in the final solutions. Finally, the efficiency was analyzed for each network and algorithm. The results ensure the best possible configuration based on the quality of the solutions and the convergence speed of the algorithm, depending of the population size. [ABSTRACT FROM AUTHOR]

One of the main concerns in many cities is the need to rehabilitate or expand their drainage systems. Increasing rainfall intensities related with climate change, uncontrolled growth and excessive waterproofing of cities causes that original drainage networks design have became insufficient. Inadequate drainage networks make necessary to develop rehabilitation models of existing networks. This models should be compatible with them. This paper presents an optimization methodology to generate different solutions for the existing network improvement. This methodology uses as starting point a model of the actual storm water network. In this paper the SWMM model is used to perform the hydraulic analysis of the network. Also a Pseudo-Genetic Algorithm (PGA) is used as optimization engine. This PGA model has been previously developed for other hydraulic optimization problems. The developed optimization model includes as decision variables: the rehabilitation or replacement of existing pipes, the potential location of stormwater retention tanks at certain points and their size, the initial state of the existing pumping units, and the start and stop levels of each pump. To evaluate each solution during the optimization process it has been necessary to develop a series of costs functions: a) a cost function or damage function relating the flood level and associated damage costs; b) a cost function of stormwater retention tanks which relates the investment cost in the construction of the tank with its volume; c) a pipeline rehabilitation cost function that relates the cost of rehabilitation or replacement of a pipe with its nominal diameter; d) a cost function for each pump unit giving the cost of the electrical energy consumed during the operation. Finally, the methodology developed has been applied to solve the flooding problems of a small section of the drainage network of the city of Bogota (Colombia). [ABSTRACT FROM AUTHOR]

A mathematical model is a powerful tool for simulating different scenarios that occur in a water distribution network without making physical experimentation. According to the objectives, a model can be classified into three categories: layout, design and operation. Furthermore, the level of detail is strongly related to the objective that the model tries to achieve. However, bigger amount of information does not mean better accuracy. For example, a fully detailed mathematical model of the network would lead to know every single connection. Usually, this information is so difficult to compile as imprecise. Therefore, one of the most important stages in elaborating a model consists of the model simplification, also known as skeletonization. During the works made for model skeletonization some assumptions are made. Most of the times, these assumptions may produce significant errors. Among the different techniques for network skeletonization, series pipe removal is one of the most used. It consists of replacing several adjacent pipes with a single one which must present the same head losses than the pipes being substituted. When there are no intermediate consumptions the problem has been effectively solved. The problem arises when a demand appears in one of the pipes being removed. It has been demonstrated that methods which assume constant roughness coefficients (either Hazen-Williams or Darcy equations) produce errors in the head losses. These errors may be even higher if travel time is included as a restriction, for example in water quality models. This paper reviews the most common techniques for serial pipes association. The error will be evaluated in both hydraulic and quality models. Finally, a method for exact substitution of serial pipes with intermediate demands is proposed. This method imposes two restrictions (head losses and travel time) and gives exact results when the flow direction is known. The method is tested with an example that highlights the results. [ABSTRACT FROM AUTHOR]

EPANET is probably the most widespread model for water distribution network (WDN). More than twenty years after its appearance, it has become a global reference both for hydraulic and quality analysis of water networks. In 2000, EPANET 2 appears, which includes as most important computational feature a new Toolkit. This toolkit was a library of functions allowing the modification of network data and reading results without access to the appropriate files. Over time, the use of this library has been the communication protocol for every application developers who use the method propose by Todini and Pilati to analyze the behavior of WDN. This library also provides interface tools that allow the execution of a simulation from an external application, as long as the network characteristics had been previously defined. This paper presents a change in the original EPANET model, including a new menu in the graphical user interface (GUI). This menu allows users to set up a personal collection of Add-In tools, which use both project data and simulation results. These tools can be customized and allows to extend the analysis capability of EPANET. All of them can access EPANET functions through the Toolkit and were developed by the authors during the Spanish translation of EPANET, taking into account the homologous Add-in tools developed for SWMM model. As an example of the operation and capabilities of this new menu, several applications integrated as EPANET add-in tools are presented. These tools perform tasks such as importing data network from both CAD and GIS systems, the design of WDNs using genetic algorithms, automatic assignment of initial water quality to network nodes; the skeletonization of a network or optimization of pumping schedule in the network in order to achieve a minimum energy cost. [ABSTRACT FROM AUTHOR]

Hydraulic models of water supply networks are widely used by utility companies to assist in decision making. The reliability of the model strongly depends on the quality of its calibration, that is, the correspondence between the measure variables and the calculated ones. When dealing the model is static, the calibration is easy to reach for average values of the variables. On the contrary, dynamic models need to spatially allocate demands and distribute them among the nodes of the network, which complicate the problem. The paper proposes a methodology for preliminary calibration of hydraulic models based on advanced calibration techniques. This methodology is applied to models with both pressure-dependent and independent demands. Pressure-dependent demands are related to leakages and are spatially distributed according to the length of the pipes and volumetric efficiency of the district metering area (DMA) being considered. In order to model leakages, the Germanopoulos model has been chosen. Thus, leakage flow is a function of the length of the pipes and the pressure along them. The equation to quantify the volume of leakage is a modification of the orifice equation. From this leakage model, a calibration process is proposed. It consists in three steps. First, a global leakage coefficient is calculated in order to satisfy daily mass balance of produced unaccounted and consumed water. In the second step, a time demand pattern is calculated. After these two steps a preliminary model is obtained. Finally, a conventional calibration process is done using discrepancies between pressure measurements and model result to adjust both roughness and minor losses coefficients. In order to validate this calibration methodology, a case study was used in Guayaquil (Ecuador) in which three DMA were studied. The results showed that the method converges very quickly and is effective regardless the volumetric efficiency of the network. [ABSTRACT FROM AUTHOR]

Storm tanks are an increasingly solution used to control floods caused by the increase of runoff flows generated by rain. To expedite the construction of these infrastructures and reduce downtime of urban supplies plastic modular elements as basic building structures are used. This paper presents the characterization of this sort of modular elements determining its energy dissipation to the passage of the water and comparing the hydraulic behavior of modular deposits to conventional ones. This paper justifies the use of computational fluid dynamic techniques (CFD) for characterizing hydraulic behavior of these modular elements based on three-dimensional models. These models have been validated by an experimental prototype built in laboratory. This one consists of a channel along which various completely monitored modular blocks are disposed in order to analyze both, circulating flows and water levels reached at different points of the system. The final result is a validated and calibrated model that allows to represent the behavior of this kind of infrastructures against strong intensity storms. A one-dimensional model of such structures is proposed as a way to join it with a specific computational model of drainage networks analysis as is the case of SWMM. Finally, a comparison between the results obtained by CFD techniques and those obtained after adjustment in SWMM is shown. [ABSTRACT FROM AUTHOR]