Une approche pour la comparaison, du point de vue fonctionnement hydraulique, de propositions d'extension d'un réseau d'assainissement

Les outils informatiques développés dans le cadre de la conception des réseaux d'assainissement permettent de concevoir plusieurs solutions de réseaux pour un même problème. Il revient ensuite au décideur de choisir quelle solution retenir. Le problème qui se pose alors est la comparaison des propositions selon des critères économiques, écologiques, de fonctionnement, de maintenance, .... La difficulté vient du fait que certains de ces critères sont difficiles à évaluer. Nous présentons dans cet article une méthode permettant d'évaluer l'un de ces critères : le fonctionnement global d'un réseau d'assainissement suite à l'extension de ce dernier. Cette méthode est basée sur des simulations hydrauliques. Or ces simulations donnent des informations en chaque noeud du réseau (histogrammes de vitesses, débits ou hauteurs de charge) et non une indication sur la qualité de fonctionnement du réseau dans son ensemble. Il nous a donc fallu élaborer une technique d'agrégation permettant de passer de l'élément isolé (le tronçon) à l'ensemble organisé (le réseau). Cette technique d'agrégation utilise les notions de "période d'insuffisance" d'un tronçon qui est la période de retour d'une pluie pour laquelle ce tronçon dépasse un certain seuil de dysfonctionnement (dans notre cas, le débordement) et de sensibilité du tissu urbain à un dysfonctionnement hydraulique du réseau. Cette dernière notion est nécessaire car certains tronçons peuvent très bien déborder sans induire de désordres apparents s'ils ont, par exemple, une capacité d'écoulement faible et/ou s'ils se trouvent dans une zone non bâtie. Les informations nécessaires à l'utilisation de cette méthode étant souvent de qualité inégale en termes de précision, nous avons pris le parti de raisonner non sur des valeurs déterminées ais sur des classes d'appartenance modélisées sous forme de sous-ensembles flous.Software packages developed for the design of urban storm drainage networks allow several solutions to be proposed for the same problem. It then falls to the designer to choose which solution to use, the main problem being the evaluation of the efficiency (quality) of each solution. A multi-criteria approach represents one theoretical solution to the problem. This necessitates the determination of which criteria to use and how to evaluate them. In this paper, we present a method of evaluation of the criteria related directly to the functioning of an urban storm drainage network after its extension. This method is developed on the basis of hydraulic simulations of the network. These simulations produce results (histograms of discharge, water levels, rates of filling, hydraulic head, ...) for each pipe. Given these results, the designer must be able to assess whether the proposed solution is satisfactory, and then compare it with other solutions. The problem is therefore to be able to evaluate a complete network, whereas the results of conventional simulations present a fragmented and partial view of its functioning (pipe by pipe). A solution to this problem is proposed in the form of a tool, able to calculate a single combined value from the simulation results. The following calculation steps are proposed:1. First we model the effectiveness of each pipe. To do that, we determine the "return period of failure" of a pipe which is the return period of a rainfall for which the pipe passes a certain level of failure (in this paper, we take the level of failure as the state of overflow). The rainfall model used is the same one used for the design of the network. Then we attribute a numerical value (S) for the operation of a pipe according to its return period of failure by way of a satisfaction function. 2. Secondly we model the weighting given to each pipe. This weighting is constructed from the discharge capacity of the pipe and the sensitivity of the urban fabric (in proximity to the pipe) to system failure. The discharge capacity is calculated using Manning's formula on the basis of diameter, slope and internal roughness. The value of the coefficient (R), which indicates the sensitivity, necessitates a good knowledge of the urban fabric. Among the important variables related to this factor, we can identify the population density, the traffic density and the density of land use -DLU- (this variable is identified by the density of residential land use, the density of commercial land use, ...). We can then write R=f(density of population, density of traffic, DLU,...). Considering the difficulty of the identification of (f), we preferred to explore an expert approach. The rules have been identified from a bibliographical analysis and limited expertise. An example of theses rules is presented here : IF density of population is high and density of commercial land use is average THEN the degree of sensibility is average. The examination of the identified rules shows the use of words like low, average and high. To model this linguistic qualifying information, we have chosen fuzzy sets. Also the inferences of fuzzy information are treated by using operations of fuzzy logic. 3. Finally, we aggregate the results with the following equation:     nC=∑QaixRix∆Si  i=1where DSi=Si - Si' represents a measure of the effect of network modification upon the operation of the pipe i (Si and Si' are the effectiveness of the pipe respectively before and after the proposed modification), Qai is the discharge capacity of the pipe i, Ri is the coefficient of sensitivity of the area to failure associated with pipe i and C is a factor which quantifies the effect on the general operation of the network. With the coefficient C, the designer is now able to classify the different solutions of extension of an existing urban drainage network according to their impacts on its functioning and to introduce this classification order in a multi-criteria method

Recommender Thermometer for Measuring the Preparedness for Flood Resilience Management

A range of various thermometers and similar scales are employed in different human and resilience management activities: Distress Thermometer, Panic Thermometer, Fear Thermometer, fire danger rating, hurricane scales, earthquake scales (Richter Magnitude Scale, Mercalli Scale), Anxiety Thermometer, Help Thermometer, Problem Thermometer, Emotion Thermometer, Depression Thermometer, the Torino scale (assessing asteroid/comet impact prediction), Excessive Heat Watch, etc. Extensive financing of the preparedness for flood resilience management with overheated full-scale resilience management might be compared to someone ill running a fever of 41°C. As the financial crisis hits and resilience management financing cools down it reminds a sick person whose body temperature is too low. The degree indicated by the Recommender Thermometer for Measuring the Preparedness for Flood Resilience Management with a scale between Tmin=34,0° and Tmax=42,0° shows either cool or overheated preparedness for flood resilience management. The formalized presentation of this research shows how changes in the micro, meso and macro environment of resilience management and the extent to which the goals pursued by various interested parties are met cause corresponding changes in the “temperature” of the preparedness for resilience management. Global innovative aspects of the Recommender Thermometer developed by the authors of this paper are, primarily, its capacity to measure the “temperature” of the preparedness for flood resilience management automatically, to compile multiple alternative recommendations (preparedness for floods, including preparing your home for floods, taking precautions against a threat of floods, retrofitting for flood-prone areas, checking your house insurance; preparedness for bushfires, preparedness for cyclones, preparedness for severe storms, preparedness for heat waves, etc.) customised for a specific user, to perform multiple criteria analysis of the recommendations, and to select the ten most rational ones for that user. Across the world, no other system offers these functions yet. The Recommender Thermometer was developed and fine-tuned in the course of the Android (Academic Network for Disaster Resilience to Optimise educational Development) project

Aldosterone Antagonists in Monotherapy Are Protective against Streptozotocin-Induced Diabetic Nephropathy in Rats

Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers

Genetic studies of IgA nephropathy: past, present, and future

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and an important cause of kidney disease in young adults. Highly variable clinical presentation and outcome of IgAN suggest that this diagnosis may encompass multiple subsets of disease that are not distinguishable by currently available clinical tools. Marked differences in disease prevalence between individuals of European, Asian, and African ancestry suggest the existence of susceptibility genes that are present at variable frequencies in these populations. Familial forms of IgAN have also been reported throughout the world but are probably underrecognized because associated urinary abnormalities are often intermittent in affected family members. Of the many pathogenic mechanisms reported, defects in IgA1 glycosylation that lead to formation of immune complexes have been consistently demonstrated. Recent data indicates that these IgA1 glycosylation defects are inherited and constitute a heritable risk factor for IgAN. Because of the complex genetic architecture of IgAN, the efforts to map disease susceptibility genes have been difficult, and no causative mutations have yet been identified. Linkage-based approaches have been hindered by disease heterogeneity and lack of a reliable noninvasive diagnostic test for screening family members at risk of IgAN. Many candidate-gene association studies have been published, but most suffer from small sample size and methodological problems, and none of the results have been convincingly validated. New genomic approaches, including genome-wide association studies currently under way, offer promising tools for elucidating the genetic basis of IgAN

Brain energy rescue:an emerging therapeutic concept for neurodegenerative disorders of ageing

The brain requires a continuous supply of energy in the form of ATP, most of which is produced from glucose by oxidative phosphorylation in mitochondria, complemented by aerobic glycolysis in the cytoplasm. When glucose levels are limited, ketone bodies generated in the liver and lactate derived from exercising skeletal muscle can also become important energy substrates for the brain. In neurodegenerative disorders of ageing, brain glucose metabolism deteriorates in a progressive, region-specific and disease-specific manner — a problem that is best characterized in Alzheimer disease, where it begins presymptomatically. This Review discusses the status and prospects of therapeutic strategies for countering neurodegenerative disorders of ageing by improving, preserving or rescuing brain energetics. The approaches described include restoring oxidative phosphorylation and glycolysis, increasing insulin sensitivity, correcting mitochondrial dysfunction, ketone-based interventions, acting via hormones that modulate cerebral energetics, RNA therapeutics and complementary multimodal lifestyle changes

Geographic Differences in Genetic Susceptibility to IgA Nephropathy: GWAS Replication Study and Geospatial Risk Analysis

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