Optimising water distribution systems using a weighted penalty in a genetic algorithm

Genetic algorithms (GAs) have become the preferred water system design optimisation technique for many researchers and practitioners. The main reason for using GAs is their ability to deal with nonlinear complex optimisation problems. The optimal decision in terms of designing, expansion/extending, addition or rehabilitation of water supply systems has to review possible options and select a cost-effective and efficient solution. This paper presents a new approach in determining a penalty value depending on the degree of failure, of the set pressure criteria, and the importance of the link supplying a specific node. Further modifications are also made in the cross-over and mutation procedures to ensure an increase in algorithm convergence. EPANET, a widely used water distribution network simulation model, is used in conjunction with the proposed newly developed GA for the optimisation of water distribution systems. The developed GA procedure has been incorporated in a software package called GANEO, which can be used to design new networks, analyse existing networks and prioritise improvements on existing networks. The developed GA has been tested on several international benchmark problems and has proved to be very efficient and robust. The EPANET hydraulic modelling software as well as the developed GANEO software, which performs the optimisation of the water distribution network, is freeware. The software provides a tool for consulting engineers to optimise the design or rehabilitation of a water distribution network.Keywords: optimising, water distribution system, genetic algorith

EXERCISE-INDUCED SYMPATHETIC FFA MOBILIZATION IN VMH-LESIONED RATS IS NORMALIZED BY FASTING

This study investigates whether reduced sympathetic responses during physical exercise in ventromedial hypothalamus (VMH)-lesioned obese rats are the direct result of damage to hypothalamic circuits or a secondary effect of the altered metabolism in obesity. Obese, VMH-lesioned rats and lean controls were deprived of food for 48 h and submitted to 15 min of swimming. Food-deprived lean and obese rats displayed increased free fatty acid mobilization and utilization, whereas blood glucose concentrations were decreased. Basal plasma insulin levels were reduced by fasting in both groups, when compared with the ad libitum situation, but remained higher in the obese animals. Fasting augmented the norepinephrine response of the obese rats, resulting in equal profiles in lean and obese animals. These results indicate that VMH-lesioned animals are able to increase the sympathetic activation of adipose tissue during exercise to overcome an energy deficiency. Therefore, the function of the VMH in the regulation of the sympathetic nervous system controlling metabolism can be taken over by redundant mechanisms. The reduced sympathetic activity in ad libitum fed VMH-lesioned animals is therefore likely to be the result of the altered metabolism

EXERCISE-INDUCED SYMPATHETIC FFA MOBILIZATION IN VMH-LESIONED RATS IS NORMALIZED BY FASTING

This study investigates whether reduced sympathetic responses during physical exercise in ventromedial hypothalamus (VMH)-lesioned obese rats are the direct result of damage to hypothalamic circuits or a secondary effect of the altered metabolism in obesity. Obese, VMH-lesioned rats and lean controls were deprived of food for 48 h and submitted to 15 min of swimming. Food-deprived lean and obese rats displayed increased free fatty acid mobilization and utilization, whereas blood glucose concentrations were decreased. Basal plasma insulin levels were reduced by fasting in both groups, when compared with the ad libitum situation, but remained higher in the obese animals. Fasting augmented the norepinephrine response of the obese rats, resulting in equal profiles in lean and obese animals. These results indicate that VMH-lesioned animals are able to increase the sympathetic activation of adipose tissue during exercise to overcome an energy deficiency. Therefore, the function of the VMH in the regulation of the sympathetic nervous system controlling metabolism can be taken over by redundant mechanisms. The reduced sympathetic activity in ad libitum fed VMH-lesioned animals is therefore likely to be the result of the altered metabolism.</p

EXERCISE-INDUCED SYMPATHETIC FFA MOBILIZATION IN VMH-LESIONED RATS IS NORMALIZED BY FASTING

This study investigates whether reduced sympathetic responses during physical exercise in ventromedial hypothalamus (VMH)-lesioned obese rats are the direct result of damage to hypothalamic circuits or a secondary effect of the altered metabolism in obesity. Obese, VMH-lesioned rats and lean controls were deprived of food for 48 h and submitted to 15 min of swimming. Food-deprived lean and obese rats displayed increased free fatty acid mobilization and utilization, whereas blood glucose concentrations were decreased. Basal plasma insulin levels were reduced by fasting in both groups, when compared with the ad libitum situation, but remained higher in the obese animals. Fasting augmented the norepinephrine response of the obese rats, resulting in equal profiles in lean and obese animals. These results indicate that VMH-lesioned animals are able to increase the sympathetic activation of adipose tissue during exercise to overcome an energy deficiency. Therefore, the function of the VMH in the regulation of the sympathetic nervous system controlling metabolism can be taken over by redundant mechanisms. The reduced sympathetic activity in ad libitum fed VMH-lesioned animals is therefore likely to be the result of the altered metabolism.</p

Functional capillary density decreases after the first week of life in term neonates

Background: Changes in the microcirculation have been recognized to play a crucial role in many disease processes. In premature neonates, functional capillary density (FCD) decreases during the first months of life. Objectives: The aims of this study were to obtain microcirculatory parameters in term neonates and older children who did not present with compromised respir

Estimating non-response bias in a survey on alcohol consumption: comparison of response waves

AIMS: According to 'the continuum of resistance model' late respondents can be used as a proxy for non-respondents in estimating non-response bias. In the present study, the validity of this model was explored and tested in three surveys on alcohol consumption. METHODS: The three studies collected their data by means of mailed questionnaires on alcohol consumption whereby two studies also performed a non-response follow-up. RESULTS: Comparisons of early respondents, late respondents and non-respondents in one study showed some support for 'the continuum of resistance model', although another study could not confirm this result. Comparison of alcohol consumption between three time response groups showed no significant linear pattern of differences between response waves. CONCLUSIONS: The hypothesis that late respondents are more similar to non-respondents than early respondents, could not be confirmed or rejected. Repeated mailings are effective in obtaining a greater sample size, but seem ineffective in improving the representativeness of alcohol consumption surveys

Hepatitis C elimination in the Netherlands (CELINE): Study protocol for nationwide retrieval of lost to follow-up patients with chronic hepatitis C

Background The Netherlands has a low hepatitis C virus (HCV) prevalence, estimated at 0.16%. Previous studies have shown that up to 30% of the diagnosed HCV population in the Netherlands has been lost to follow-up (LTFU). Retrieval of these patients could halt progression of liver disease in infected patients, reduce the number of infected individuals and limit HCV transmission. Several regional Dutch retrieval projects have already been executed, which demonstrated that retrieval is feasible. Therefore, we initiated a nationwide retrieval project, aiming to achieve microelimination in previously diagnosed but LTFU patients with chronic HCV through retrieval. Methods Laboratory records will be used to identify possible patients with chronic hepatitis C, defined as either a positive most recent HCV RNA or positive HCV antibodies without known RNA result. Reviewing patient records and obtaining current contact information from municipality databases will identify LTFU patients who ar