Search results for " Capa"
showing 10 items of 1248 documents
Étude sur les réformes curriculaires par l'approche par compétences en Afrique
2009
Cette étude vise trois objectifs : réaliser un état des lieux des processus de réformes curriculaires en éducation de base en Afrique pour identifier les problèmes rencontrés, les résultats positifs et les "bonnes pratiques", aider les responsables des systèmes éducatifs à prendre des mesures pertinentes et accompagner les réformes et enfin aider les bailleurs de fonds à mieux comprendre les effets de leur aide et à mieux cibler les projets de réforme en termes de coût et d'efficacité à tous les niveaux des systèmes éducatifs impliqués.
Taller virtual de resolución de problemas
2017
En esta comunicación presentamos una experiencia diseñada e implementada para analizar la resolución de problemas de un grupo de cinco estudiantes con altas capacidades matemáticas a través de videoconferencia. Se describen varias sesiones en la que se conectaron tres estudiantes de Granada con dos de Valencia de 1º y 2º de E.S.O. en un taller virtual de enriquecimiento matemático basado en la resolución de problemas en grupo para iniciar a los estudiantes en la demostración matemática. En las investigaciones se ha reconocido el trabajo en grupo como una forma de atención recomendada para este colectivo de estudiantes. El uso de plataformas como Google Hangout o Skype, que permiten hacer vi…
Volumes, heat capacities and solubilities of amyl compounds in decyltrimethylammonium bromide aqueous solutions
1989
Apparent molar heat capacities and volumes of amylamine (PentNH2) 0.02m, capronitrile (PentCN) 0.02m and nitropentane (PentNO2) 0.009m in decyltrimethylammonium bromide (DeTAB) micellar solutions, in water and in octane were measured at 25°C. By assuming that their concentration approaches the standard infinite dilution state, heat capacities and volumes were rationalized by means of previously reported equations following which the distribution constant between the aqueous and the micellar phase and heat capacity and volume of the additives in both phases are simultaneously derived. The present results are compared to those we have previously obtained for pentanol (PentOH). The thermodynam…
Binding between (Ethylene Oxide)13−(Propylene Oxide)30−(Ethylene Oxide)13 and Sodium Decanoate. Volume, Enthalpy, and Heat Capacity Studies
2002
Volume, enthalpy, and heat capacity of transfer (ΔYt) of (ethylene oxide)13−(propylene oxide)30−(ethylene oxide)13 (L64), at some concentrations, from water to the aqueous sodium decanoate (NaDec) solutions as functions of the surfactant concentration (mS) were determined at 298 K. The copolymer was studied in both the unassociated and associated forms. For a given L64 concentration (mC), the ΔYt vs mS profiles for the volume and the enthalpy are equal but different from that of the heat capacity because the latter contains also the relaxation terms. The experimental data were analyzed by assuming the distribution of L64 between the aqueous and the micellar phases and the shift of micelliza…
Heat Capacity of Transfer of (Ethylene oxide)13-(propylene oxide)30-(ethylene oxide)13 from Water to the Aqueous Anionic Surfactant Solutions at 298 …
2004
Heat capacities of transfer (ACpt) of unimeric (ethylene oxide)(13)-(propylene oxide)(30)-(ethylene oxide)(13) from water to the aqueous surfactant solutions as functions of the surfactant concentrations (m(S)) were determined at 298 K. The surfactants investigated are sodium hexanoate, sodium heptanoate, sodium octanoate, sodium undecanoate, and sodium dodecanoate. For short alkyl chain surfactants, the profiles of the DeltaCp(t) versus ms curves show maxima and minima; for long alkyl chain surfactants, the maximum becomes sharper and moved to lower ms values whereas the minimum tends to disappear. These experimental trends are different from those of the enthalpy in agreement with the fac…
Thermodynamics of Solubilization of Pentanol in Sodium Dodecyl Sulfate-Dodecyldimethylamine Oxide Mixed Micelles
1994
Abstract Heat capacity and density measurements of pentanol (PeOH)-sodium dodecyl sulfate (NaDS)-dodecyldimethylamine oxide-water mixtures were carried out at 0.03 m PeOH as a function of the total surfactants concentration (mc) at different ratios (XNaDS). From experimental data, the apparent molar volumes (VΦ,R) and heat capacities (CΦ,R) of PeOH in the surfactants mixture solutions were calculated. As a general feature, at a given mixture composition, VΦ,R increases monotonically with mt as observed in pure surfactants. In the cases of XNaDS = 0.1 and 0.3, VΦ,R drops at about 0.1 and 0.15 mt respectively. The decreasing CΦ,R VS mt curve shows peculiarities which were ascribed to the pres…
Thermodynamic properties of water-β-cyclodextrin-dodecylsurfactant ternary systems
1995
Densities, heat capacities and conductivities of water-surfactant-β-cyclodextrin (β-CD) ternary systems were determined at 25°C. The surfactants studied were sodium dodecylsulfate (NaDS) and dodecyltrimethylammonium bromide (DTAB). From conductivity data, apparent critical micelle concentrations (cmc*) and degree of ionization of micelles were obtained at a fixed β-CD concentration (mCD). From the cmc* value and that in water (cmc) the stoichiometry of the surfactant-β-CD complex was calculated. At a given mCD, the apparent molar volume Vϕ,CD and heat capacity Cϕ,CD of β-CD in the two surfactants were calculated as functions of surfactant concentration mS. For both NaDS and DTAB, Vϕ,CD incr…
Enzyme replacement therapy for mucopolysaccharidosis VI: evaluation of long-term pulmonary function in patients treated with recombinant human N-acet…
2010
Pulmonary function is impaired in untreated mucopolysaccharidosis type VI (MPS VI). Pulmonary function was studied in patients during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB; rhN-acetylgalactosamine 4-sulfatase). Pulmonary function tests prior to and for up to 240 weeks of weekly infusions of rhASB at 1 mg/kg were completed in 56 patients during Phase 1/2, Phase 2, Phase 3 and Phase 3 Extension trials of rhASB and the Survey Study. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and, in a subset of patients, maximum voluntary ventilation (MVV), were analyzed as absolute volume in liters. FEV1 and FVC showed little change f…
Antioxidant capacity of infant fruit beverages: influence of storage and in vitro gastrointestinal digestion
2008
Reyes.Barbera@uv.es; M.J.Lagarda@uv.es; Rosaura.Farre@uv.es The total antioxidant capacity of three beverages based on fruit juice, milk and cereals, intended for infants and young children up to 3 years of age was evaluated by two methods Trolox Equivalent Antioxidant Capacity and Oxygen Radical Absorption Capacity. Results: According to the total antioxidant values obtained by both methods, the beverages can be ranked as follows: grape-orange-banana > peach-apple > pineapple-banana. Ascorbic acid was the main contributor (60%) to the total antioxidant capacity, while the contribution of skimmed milk was less than 1.2%. After one month of storage at -20 ºC, significant losses (p < 0.05) in…
Deferiprone and idebenone rescue frataxin depletion phenotypes in a Drosophila model of Friedreich's ataxia
2013
Friedreich's ataxia (FRDA), the most common inherited ataxia, is a neurodegenerative disease caused by a reduction in the levels of the mitochondrial protein frataxin, the function of which remains a controversial matter. Several therapeutic approaches are being developed to increase frataxin expression and reduce the intramitochondrial iron aggregates and oxidative damage found in this disease. In this study, we tested separately the response of a Drosophila RNAi model of FRDA ( Llorens et al., 2007) to treatment with the iron chelator deferiprone (DFP) and the antioxidant idebenone (IDE), which are both in clinical trials. The FRDA flies have a shortened life span and impaired motor coord…