La difficile prise en main des petits périmètres irrigués par les agriculteurs en Algérie : cas du périmètre de Ladrat

Un enjeu important pour la réussite du transfert de gestion des systèmes irrigués à des associations d'irrigants est l'appropriation par les agriculteurs de ces nouvelles organisations. Cet enjeu est en particulier présent dans les pays qui ont connu une forte intervention de l'État dans le secteur agricole. En Algérie, les pouvoirs publics ont entamé, à la fin des années 1990, un processus de concession des ouvrages d'irrigation de petite et moyenne hydraulique à des associations d'irrigants. La présente étude analyse le fonctionnement et la gouvernance de l'association d'irrigants qui gère le périmètre irrigué de Ladrat, dans la wilaya de Médéa. Le bureau exécutif de l'association perpétue des pratiques de gestion très administratives. L'association a une capacité d'action limitée, qui se traduit notamment par un taux élevé de non-paiement du service de l'eau. Les conflits ne sont pas gérés par une négociation au niveau de l'association, qui fait souvent appel à l'administration. Tout cela traduit une faible appropriation de l'association par les agriculteurs. Malgré toutes ces difficultés, les agriculteurs se déclarent majoritairement favorables à une gestion associative. Ils critiquent plutôt le fonctionnement administratif de l'association et leur manque d'implication dans la gouvernance. Le manque d'appropriation par les agriculteurs des associations d'irrigants constituées par l'État n'implique ainsi pas nécessairement que ces agriculteurs refusent le principe d'une gestion des périmètres irrigués par des associations d'irrigants. (Résumé d'auteur

Genetic ablation of calcium-independent phospholipase A2γ induces glomerular injury in mice

Glomerular visceral epithelial cells (podocytes) play a critical role in the maintenance of glomerular permselectivity. Podocyte injury, manifesting as proteinuria, is the cause of many glomerular diseases. We reported previously that calcium-independent phospholipase A(2)γ (iPLA(2)γ) is cytoprotective against complement-mediated glomerular epithelial cell injury. Studies in iPLA(2)γ KO mice have demonstrated an important role for iPLA(2)γ in mitochondrial lipid turnover, membrane structure, and metabolism. The aim of the present study was to employ iPLA(2)γ KO mice to better understand the role of iPLA(2)γ in normal glomerular and podocyte function as well as in glomerular injury. We show that deletion of iPLA(2)γ did not cause detectable albuminuria; however, it resulted in mitochondrial structural abnormalities and enhanced autophagy in podocytes as well as loss of podocytes in aging KO mice. Moreover, after induction of anti-glomerular basement membrane nephritis in young mice, iPLA(2)γ KO mice exhibited significantly increased levels of albuminuria, podocyte injury, and loss of podocytes compared with wild type. Thus, iPLA(2)γ has a protective functional role in the normal glomerulus and in glomerulonephritis. Understanding the role of iPLA(2)γ in glomerular pathophysiology provides opportunities for the development of novel therapeutic approaches to glomerular injury and proteinuria

Efficient solar heterogeneous photocatalytic degradation of metronidazole using heterojunction semiconductors hybrid nanocomposite, layered double hydroxides

This study focuses on the synthesis of various nanocomposites with heterojunction structures, MgAl-LDH (LDH ¼ layered double hydroxides) hybrid with semiconductor such as MoO3 and CuO. These solids were synthesized by co-precipitation method at constant pH and have been characterized extensively using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and transmission electron microscopy-energy dispersive X-ray (TEMEDX) methods. The catalytic activity of nanocomposites was tested in the photocatalytic degradation under solar irradiation of emerging pollutants as the pharmaceutical metronidazole (MNZ). The experimental parameters, including initial MNZ concentration, the nature of oxide incorporate in the photocatalyst, catalyst loading were explored. All the synthesized samples showed high photocatalytic performances; the highest photocatalysis efficiency was achieved with the photocatalyst dose 1.5 g/L and initial MNZ concentration of 10 mg/L at neutral pH. The photocatalytic experimental results were fitted very well to the Langmuir-Hinshelwood model. From the obtained results the calcined LDH/semiconductors could be efficient for the photocatalytic process under solar irradiation of pharmaceuticals and may contribute in environmental remediation

Inhibiting ERK Activation with CI-1040 Leads to Compensatory Upregulation of Alternate MAPKs and Plasminogen Activator Inhibitor-1 following Subtotal Nephrectomy with No Impact on Kidney Fibrosis

Extracellular-signal regulated kinase (ERK) activation by MEK plays a key role in many of the cellular processes that underlie progressive kidney fibrosis including cell proliferation, apoptosis and transforming growth factor β1-mediated epithelial to mesenchymal transition. We therefore assessed the therapeutic impact of ERK1/2 inhibition using a MEK inhibitor in the rat 5/6 subtotal nephrectomy (SNx) model of kidney fibrosis. There was a twentyfold upregulation in phospho-ERK1/2 expression in the kidney after SNx in Male Wistar rats. Rats undergoing SNx became hypertensive, proteinuric and developed progressive kidney failure with reduced creatinine clearance. Treatment with the MEK inhibitor, CI-1040 abolished phospho- ERK1/2 expression in kidney tissue and prevented phospho-ERK1/2 expression in peripheral lymphocytes during the entire course of therapy. CI-1040 had no impact on creatinine clearance, proteinuria, glomerular and tubular fibrosis, and α-smooth muscle actin expression. However, inhibition of ERK1/2 activation led to significant compensatory upregulation of the MAP kinases, p38 and JNK in kidney tissue. CI-1040 also increased the expression of plasminogen activator inhibitor-1 (PAI-1), a key inhibitor of plasmin-dependent matrix metalloproteinases. Thus inhibition of ERK1/2 activation has no therapeutic effect on kidney fibrosis in SNx possibly due to increased compensatory activation of the p38 and JNK signalling pathways with subsequent upregulation of PAI-1

Planification de la maintenance d'un parc de turbines-alternateurs par programmation mathématique

RÉSUMÉ Une population grandissante de groupes turbines-alternateurs dans les centrales hydroélectriques arrive à sa fin de vie utile et les gestionnaires appréhendent la concurrence des arrêts pour des rénovations majeures avec un nombre tel que les ressources disponibles dans une même période ne seraient pas suffisantes. Ces retraits du réseau peuvent durer jusqu'à une année entière et mobilisent des ressources importantes en plus de la perte de production électrique. Les prévisions à la hausse des ventes à l'export et des rythmes de production sévères font craindre la mise à l'arrêt de beaucoup de groupes en même temps. Actuellement, le jugement des experts est au coeur des décisions des retraits qui se basent essentiellement sur des inspections périodiques et des mesures effectuées in-situ et dont les résultats sont centralisés chez l'équipe de planification des retraits. La nature aléatoire des phénomènes de dégradations qui ont lieu, font en sorte que la capacité de prévision de l'usure par l'inspection a un caractère de court-terme. Une vision des rénovations majeures sur le long terme est activement recherchée par les gestionnaires dans un souci de justification et de rationalisation des ressources budgétaires allouées aux rénovations. Les gestionnaires disposent d’une quantité impressionnante de données. Parmi elles, figurent la production horaire de chaque groupe depuis plusieurs années, l'historique des réparations sur chaque organe ainsi que les retraits majeurs effectués depuis les années 1950. Dans ce projet de recherche, nous nous proposons de résoudre le problème de planification de la maintenance d’un parc de 90 groupes turbines-alternateurs du réseau de production d'Hydro- Québec sur un horizon de 50 ans. Nous développons une méthodologie scientifique et rationnelle de préparation des plans des retraits qui serviront de support à la prise de décision en exploitant les données de mesures et les historiques disponibles tout en respectant un ensemble de contraintes techniques et économiques. Pour respecter la confidentialité de certaines données, toutes les dénominations originales ont été modifiées pour les rendre anonymes. Ce problème de planification est traité comme un problème d’optimisation avec contraintes. D'abord, un groupe est étudié pour ressortir les organes les plus influents. Un modèle de taux de défaillance est développé pour prendre en compte les caractéristiques technologiques de l'organe et d'utilisation du groupe. Ensuite, des stratégies de remplacements et de réparations sont----------ABSTRACT A growing number of Hydro-Québec's hydro generators are at the end of their useful life and maintenance managers fear to face a number of overhauls exceeding what can be handled. Maintenance crews and budgets are limited and these withdrawals may take up to a full year and mobilize significant resources in addition to the loss of electricity production. In addition, increased export sales forecasts and severe production patterns are expected to speed up wear that can lead to halting many units at the same time. Currently, expert judgment is at the heart of withdrawals which rely primarily on periodic inspections and in-situ measurements and the results are sent to the maintenance planning team who coordinate all the withdrawals decisions. The degradations phenomena taking place is random in nature and the prediction capability of wear using only inspections is limited to shortterm at best. A long term planning of major overhauls is sought by managers for the sake of justifying and rationalizing budgets and resources. The maintenance managers are able to provide a huge amount of data. Among them, is the hourly production of each unit for several years, the repairs history on each part of a unit as well as major withdrawals since the 1950's. In this research, we tackle the problem of long term maintenance planning for a fleet of 90 hydro generators at Hydro-Québec over a 50 years planning horizon period. We lay a scientific and rational framework to support withdrawals decisions by using part of the available data and maintenance history while fulfilling a set of technical and economic constraints. We propose a planning approach based on a constrained optimization framework. We begin by decomposing and sorting hydro generator components to highlight the most influential parts. A failure rate model is developed to take into account the technical characteristics and unit utilization. Then, replacement and repair policies are evaluated for each of the components then strategies are derived for the whole unit. Traditional univariate policies such as the age replacement policy and the minimal repair policy are calculated. These policies are extended to build alternative bivariate maintenance policy as well as a repair strategy where the state of a component after a repair is rejuvenated by a constant coefficient

Cations extraction of sandy-clay soils from Cavado valley, Portugal, using sodium salts solutions

Cases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. Samples taken from various sites, after physico-chemical characterisation, were subjected to clay dissolution tests, using sodium salts of different ionic forces, to detect the relationship between certain physico-chemical parameters of water, such as pH, nitrate, chloride and sulphate content, in the dissolution of clay and the subsequent extraction of such cations as Al, Fe and K. In acidic sandy clay soils, the mineralogical composition of which was characterised by a predominance of quartz, micas, kaolinite and K-feldspars, decreases of the clay material/water pH ratio increases dissolution of the micaceous and K-feldspars phases. The presence of nitrates in the aqueous solution apparently advanced the extraction of all three cations Al, Fe and K. The specific surface area of the clay material showed a significant correlation with the main kinetic parameters of cation extraction.Têm ocorrido casos de contaminações de águas de poços, por metais, no vale do Rio Cávado, região noroeste de Portugal. A princípio, poderiam ser explicáveis pela elevada lixiviação dos solos arenoargilosos da região, quando da prática de adubações intensivas de nitrogênio em áreas agrícolas. Assim, estudaram-se as características do intemperismo natural dos solos, particularmente da fração argila, característica da margem norte do rio Cávado. Coletaram-se amostras de vários locais, que foram submetidas, após caracterização físico-química, a ensaios de dissolução a partir de soluções de sais de sódio com diferentes forças iônicas. O objetivo foi observar as relações de determinados parâmetros físico-químicos da água, tais como: pH, nitratos, cloretos e sulfatos na dissolução das argilas e a conseqüente extração de espécies químicas tais como Al, K e Fe. Para solos areno-argilosos, ácidos, cuja composição mineralógica se caracteriza por um predomínio de quartzo, micas, caulinita e feldspato-K, o abaixamento do pH da suspensão solo/água promove a solubilização das fases micáceas e feldspáticas. A presença do nitrato nas soluções aquosas promoveu aparentemente a extração de todos os três cátions: Al, K e Fe. O efeito da área superfícial específica das partículas dos solos condicionou fortemente vários dos parâmetros cinéticos estudados relativos à extração dos cátions.(undefined

Software and Hardware for managing Scratch Pad Memory

This paper proposes a low-cost architecture to improve the management SPM (Scratch Pad Memory) in dynamic and multitasking modes. In this context, our management strategy SPM based on Programmable Automaton implemented in Xilinx Vertex-5 FPGA is entirely different from prior research works. SPM is generally managed by software (by a strong programming logic or by compilation). But our Programmable Automaton facilitates access to SPM in order to move code or data and liberates space in SPM. After this step, software takes over content management of SPM (what part of code or data should be placed in SPM, locates spaces of Heap and Stack). So the performance of the programs is actually improved thanks to minimization of the access latency at the DRAM (Dynamic Random Access Memory or Main Memory)

Using Oxford’s Strategy Inventory of Language Learning (SILL) to Assess the Strategy Use of a Group of First and Third Year EFL Algerian University Students

The present study aims at investigating the patterns of language learning strategy use employed by two groups of students enrolled in a three-year English degree course in the department of English of the University of Algiers 2, each one including 56 learners among first and third-year students. To reach this objective, Oxford’s Strategy Inventory of Language Learning (SILL) (1990) along with a background questionnaire (a modified version of Oxford’s background questionnaire) administered to first-year and third-year students. The findings indicate that participants from both years use language learning strategies, but with differences in type and frequency. Third-year students reported a high frequent use of metacognitive strategies, whereas first-year students reported a high use of compensation strategies. The results also indicate that female subjects’ strategy use was higher than that of male subjects in all the types and categories of the Strategy Inventory of Language Learning. Based on the findings of the present study, some pedagogical implication were suggested to encourage students to reflect on their own strengths and weaknesses in skills and content courses and self-regulate learning so as to make progress with teachers’ assistance