667 research outputs found

    Bilan hydrologique et envasement du barrage Saboun (Maroc)

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    La présente étude s'inscrit dans le cadre d'un programme de recherche sur la gestion des lacs et barrages collinaires en zone méditerranéenne HYDROMED. Elle a pour objectif le suivi hydrologique et la sédimentation du barrage collinaire Saboun, situé dans la zone de Tanger au Nord-Ouest du Maroc. Un dispositif hydro-pluviométrique automatique a été installé à ce sujet depuis novembre1997. Il a permis le suivi du bilan en eau de la retenue et l'analyse de son fonctionnement hydrologique. ParallÚlement, une étude de la bathymétrie par sondage ponctuel a montré que le taux de sédimentation est de l'ordre de 2% par an. Cette perte en eau de la capacité totale de la retenue est une conséquence directe d'une forte dégradation des sols du bassin versant estimée à 115 T/ha/an.It is proposed that many Mediterranean countries could make better use of their water resources by constructing small hill reservoirs. Since 1980, Morocco has built more than 158 small dams in order to meet the requirements of rural population water use. Due to both environmental degradation and bad management, these small infrastructures are now in a critical situation. Furthermore, pollution and siltation, resulting in a deterioration of water quality and a reduction of water capacity, are problems at these sites.The present study is part of the HYDROMED research program on the hydrological balance of small dams in the Mediterranean area. Its objective is the monitoring of hydrological balance and siltation of a small dam, Saboun, located in Tangier in Northwest Morocco. A remote hydrological station was installed in November 1997. This station allowed the examination of the dam water balance and analyses of its hydrological function.The analyses of water balance demonstrated that the volume of water stored in the Saboun reservoir increased rapidly in November 1997, and was then followed by a progressive decrease. The load factor varied from 1.9 in 1997/98 to approximately 2 times the current capacity of reservoir, to only 0.3 in the following year 1998/99. These results show that even for a short hydrological period (2 years), the hydrological balance of the Saboun reservoir varied greatly as a result of the irregularity of its hydrological parameters. The essential reasons for this variability were the rainfall characteristics that control the runoff from the watershed and bad management practices.In addition, a bathymetric survey was carried out by a punctual method to estimate the rate of dam siltation and sedimentation from the watershed. The results of this control demonstrated that the dam siltation rate was about 2 % per year. This loss of total water retention capacity of the dam is the consequence of high specific soil degradation of the watershed. The rate of sediment delivered from watershed and deposited in the reservoir was estimated at 37 T/ha/year. The total soil erosion for watershed was estimated at 115 T/ha/year by integrating both the sediment evacuated at the time of dam overflow and the sediment deposited in stream flow. This erosion, which comes essentially from cultivated soil (95 % of the watershed surface), may have serious effects on the hydrological balance of the dam, particularly by reducing the reservoir capacity of the dam, and on the reservoir water quality

    Deterministic KPZ-type equations with nonlocal “gradient terms”

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    The main goal of this paper is to prove existence and non-existence results for deterministic Kardar–Parisi–Zhang type equations involving non-local “gradient terms”. More precisely, let Ω ⊂ RN, N≄ 2 , be a bounded domain with boundary ∂Ω of class C2. For s∈ (0 , 1) , we consider problems of the form {(-Δ)su=ÎŒ(x)|D(u)|q+λf(x),inΩ,u=0,inRN\Ω,(KPZ)where q> 1 and λ> 0 are real parameters, f belongs to a suitable Lebesgue space, Ό∈ L∞(Ω) and D represents a nonlocal “gradient term”. Depending on the size of λ> 0 , we derive existence and non-existence results. In particular, we solve several open problems posed in [Abdellaoui in Nonlinearity 31(4): 1260-1298 (2018), Section 6] and [Abdellaoui in Proc Roy Soc Edinburgh Sect A 150(5): 2682-2718 (2020), Section 7]. © 2022, Fondazione Annali di Matematica Pura ed Applicata and Springer-Verlag GmbH Germany, part of Springer Nature

    DEGENERESCENCE MALIGNE D’UN KYSTE DERMOIDE

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    Les tĂ©ratomes ovariens reprĂ©sentent 10 Ă  20℅ de l’ensemble des kystes ovariens bĂ©nins. La transformation maligne de l’un ou de plusieurs composants du tĂ©ratome est rare, elle reprĂ©sente 1 Ă  3℅ des tĂ©ratomes matures kystiques [1,2]. Le type carcinome epidermoide est retrouvĂ© dans 80℅ des cas environ [1-4], mais d’autres types sont possibles comme le mĂ©lanome et l’adĂ©nocarcinome surtout chez les femmes mĂ©nopausĂ©es

    Fifty-kDa Hyaluronic Acid Upregulates Some Epidermal Genes without Changing TNF-α Expression in Reconstituted Epidermis

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    Background: Due to its strong water binding potential, hyaluronic acid (HA) is a well-known active ingredient for cosmetic applications. However, based on its varying molecular size, skin penetration of HA may be limited. Recent studies have demonstrated that low-molecular-weight HA (LMW HA) may show a certain proinflammatory activity. We thus aimed to characterize an LMW-sized HA molecule that combines strong anti-aging abilities with efficient skin penetration but lacks potential proinflammatory effects. Methods: Total RNA and total protein were isolated from reconstituted human epidermis following incubation with HAs of various molecular weights (20, 50, 130, 300, 800 and 1,500 kDa). Tumor necrosis factor-alpha expression was determined using quantitative PCR. Genonnic and proteomic expression of various junctional proteins was determined using Affymetrix and common Western blotting techniques. Results: LMW HA of approximately 50 kDa did not significantly alter tumor necrosis factor-alpha expression compared to 20-kDa HA, but revealed significantly higher skin penetration rates than larger sized HA associated with increased expression of genes and proteins known to be involved in tight junction formation and keratinocyte cohesion. Conclusion: LMW HA of approximately 50 kDa shows better penetration abilities than larger-sized HA. In addition, LMW HA influences the expression of various genes including those contributing to keratinocyte differentiation and formation of intercellular tight junction complexes without showing proinflammatory activity. These observations contribute to current knowledge on the effects of LMW HA on keratinocyte biology and cutaneous physiology. Copyright (C) 2011 S. Karger AG, Base

    Copepod community along the Mediterranean coast of Morocco (Southwestern Alboran Sea) during spring

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    Copepod community along the Mediterranean Moroccan coast was investigated, for the first time, during April 2013. Total abundance varied from 53 to 4557 ind. m-3 and high values were found in coastal waters. Oithona nana and Paracalanus parvus dominated in the entire area and species diversity was decreasing from the West to the East. Hierarchical clustering revealed three groups of stations, depending on their geographic position (western, central and eastern areas). Indicator species analysis pointed out that Clausocalanus furcatus and Gaetanus sp. were significantly associated with Group I, Clausocalanus sp., Centropages sp. and Centropages chierchiae with Group II, whereas Temora longicornis was significantly associated with Group III. Detrended Correspondence Analysis based on the species abundance and environmental variables (temperature, salinity, chlorophyll-a), highlighted a more or less similar setting of stations which was related to salinity and temperature. The presence of three anticyclonic gyres at the northern part of the study area is suggested as the major factor acting on the variability of copepod community along the Mediterranean Moroccan coast

    Elemental (im-)miscibility determines phase formation of multinary nanoparticles co-sputtered in ionic liquids

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    Non-equilibrium synthesis methods allow to alloy bulk-immiscible elements into multinary nanoparticles, which broadens the design space for new materials.Whereas sputtering onto solid substrates can combine immiscible elements into thin film solid solutions, this is not clear for sputtering of nanoparticles in ionicliquids. Thus, the suitability of sputtering in ionic liquids for producing nanoparticles of immiscible elements is investigated by co-sputtering the systems Au-Cu (miscible), Au-Ru and Cu-Ru (both immiscible), and Au-Cu-Ru on the surface of the ionic liquid 1-butyl-3-methylimidazolium bis-trifluoromethylsulfonyl)imide [Bmim][(Tf)2N]. The sputtered nanoparticles were analyzed to obtain (i) knowledge concerning the general formation process ofnanoparticles when sputtering onto ionic liquid surfaces and (ii) information, if alloy nanoparticles of immiscible elements can be synthesized as well as (iii)evidence if the Hume-Rothery rules for solid solubility are valid for sputtered nanoparticles. Accompanying atomistic simulations using density-functional theoryfor clusters of different size and ordering confirm that the miscibility of Au-Cu and the immiscibility of Au-Ru and Cu-Ru govern the thermodynamic stabilityof the nanoparticles. Based on the matching experimental and theoretical results for the NP/IL-systems concerning NP stability, a formation model of multinaryNPs in ILs was developed

    Nonlinear elliptic problem related to the Hardy inequality with singular term at the boundary

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    Let Ω ⊂ ℝNbe a bounded regular domain of ℝNand 1 &lt; p &lt; ∞. The paper is divided into two main parts. In the first part, we prove the following improved Hardy inequality for convex domains. Namely, for all [Formula: see text], we have [Formula: see text] where d(x) = dist (x, ∂Ω), [Formula: see text] and C is a positive constant depending only on p, N and Ω. The optimality of the exponent of the logarithmic term is also proved. In the second part, we consider the following class of elliptic problem [Formula: see text] where 0 &lt; q ≀ 2* - 1. We investigate the question of existence and nonexistence of positive solutions depending on the range of the exponent q.</jats:p
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