Problemas de sistemas de ecuaciones lineales en libros de texto de 3º ESO

La resolución de problemas en matemáticas ha sido uno de los principales focos de investigación y discusión en los últimos 30 años. Las propuestas curriculares para la educación primaria y secundaria la recogen como eje transversal. El libro de texto es agente fundamental en el proceso de enseñanza aprendizaje, y en el trabajo en el aula. En este estudio se analiza cómo se plasma la resolución de problemas en un libro de texto, centrando la atención en el tema de Sistemas de Ecuaciones lineales del tercer curso de la Educación Secundaria Obligatoria. Se concluye que existen importantes características que son poco coherentes con lo especificado en el currículo oficial

Comparative study of dopaminergic activity of tetrahydro-1H-[3]-benzazepines and their precursors

The discovery of the tetrahydro-1H-[3]-benzazepine SCH23390 [1], represented one of the most important advances in the study of dopaminergic receptors due to their behavior as a selective D1 receptor antagonist. The high affinity and selectivity of this tetrahydro-1H-[3]-benzazepine has led to the search for new structures because of their potential dopaminergic activity, especially 1-aryl-substituted tetrahydro-1H-[3]-benzazepines. Furthermore, their precursors, the tetrahydroisoquinolines 1-substituted have shown to have activity for D1 and D2 dopaminergic receptors.[2] We have carried out the synthesis of tetrahydro-1H-[3]-benzazepines 1,2-di-substituted by Stevens rearrangement (SR) on tetrahydroisoquinolinium salts. Stevens rearrangement is an efficient regio- and diastereoselective synthetic methodology. [3a,b] As part of our studies, we have performed the synthesis of benzazepines with modifications at the C-1 and C-2 positions with chlorine and hydroxyl groups at A-ring which is an important factor to modulate affinity at dopaminergic receptors. The interaction of these molecules with D1 and D2 dopaminergic receptors have been studied to establish a structure-activity relationship by radioligand binding assays.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Thermorresponsive magnetic nanoparticles as target drug delivery for cancer treatment

In this research, temperature sensitive microgels with magnetic core for controlled release of 5-fluoruracil was synthesized. Magnetic nanoparticles (Fe3O4) were prepared by coprecipitation method and the surface was functionalized by acrylic acid. Polymer poly(N-isopropylacrylamide) (PNIPAM) were grown by free radical polymerization in presence of cross-liker and initiator. The size of the polymer was manipulated by changing the mole percent of the crosslinker and evaluated for their morphology (TEM), particle size, zeta potential, loading efficiency, drug content and drug release. Furthermore, microgels were tagged with FITC, a fluorochrome which could be applied for cell imaging. Cytotoxicity studies revealed that the microgels were not toxic. These complex nanoparticles (Fe3O4/pNIPAM/FITC/5-Fu) appear to be a great promise to be used in controlled drug delivery and tumor targeting.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Synthesis of New Analogues of the Bengamides to encapsulate in magnetic nanoparticles

The development and identification of new antitumoral has become a research area of great interest and maximum priority due to secondary effects of current antitumoral and the appearance of tumours resistant to these agents. Marine sponges corresponding to the Jaspidae family have proved to be a prolific source of bioactive natural products. Among these, the Bengamides have showed an important biological profile, including antitumor, antibiotic and anthelmintic properties. Due to the interest of theses natural products, we describe a study directed towards the total synthesis of this class of compounds. Then we encapsulate Bengamides in temperature sensitive microgels with a magnetic core. Magnetic nanoparticles (Fe3O 4) were prepared by coprecipitation method and the surface was functionalized by acrylic acid. Polymer poly(N-isopropylacrylamide) (PNIPAM) were grown by free radical polymerization in presence of cross-liker and initiator.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Burnout en el Supermercado: evaluando la importancia de la personalidad y situaciones de estrés

The well-known burnout syndrome includes psychological facets that have been analyzed with respect to professions with systematic and persistent social contact. However, the context is just one side of the coin, albeit important. There might be some differential vulnerability to the development of the syndrome (the other side of the coin). The study reported here is based on a previous research that observed high levels of the syndrome in cashiers of several supermarkets. Going one step further, here (a) 13 cashiers were compared with 13 workers from other sections of a supermarket, and (b) the personality traits considered by the Big Five Model were measured for estimating the efficient use of knowledge and skills required for achieving social goals (P factor).  These were the results: (a) no group differences in the syndrome between cashiers and other sections, and (b) negative correlations between the P factor and burnout scores. It is concluded that individual differences in personality might interact with the occupational context for promoting (or preventing) the burnout syndrome

Actividad antioxidante y perfiles de compuestos fenólicos en harinas de Prosopis Chileno

52 p.Las harinas de los frutos “vainas” del género Prosopis han sido utilizadas en Sud-América desde tiempos pre-hispánicos. En Chile podemos encontrar distribuida esta especie en las zonas áridas del norte del País, a partir de la harina se han elaborado diferentes productos derivados de las vainas de Prosopis, sin embargo, poco se conoce sobre sus componentes químicos con potencial nutracéutico.En la presente investigación se describen las principales características morfológicas de las vainas de Prosopis, rendimiento de las harinas y de los extractos metanólicos obtenidos. A partir de los extractos se evaluaron el contenido de fenólicos y flavonoides totales, relacionándolos con la actividad antioxidante (FRAP, TEAC y DPPH). Mediante cromatografía líquida de alta eficiencia (HPLC) acoplada con un detector de arreglo de diodo (DAD) se logró obtener los perfiles cromatográficos de cada uno de los extractos, encontrando similitudes y diferencias entre ellas. En este estudio se logró establecer las condiciones cromatográficas para la posterior identificación tentativa de los compuestos

Modelling the change in the oxidation coefficient during the aerobic degradation of phenol by acclimated activated sludge

In this work the aerobic degradation of phenol by acclimated activated sludge was studied. Results demonstrate that while the phenol removal rate by acclimated activated sludge follows the Monod model, the oxygen uptake rate obeys a Haldane-type equation. The phenol oxidation coefficient obtained at different intial phenol concentrations ranged from 1.9 to 2.6 mol O2 · mol-1 phenol. A mathematical model based on a simplified version of the catalytic mechanism of the enzyme phenol 2-monooxygenase was developed to predict transient phenol concentrations and oxygen requirements by phenol-acclimated activated sludge in batch reactors under different initial phenol concentrations. The proposed model not only adequately represents the experimental results of the present paper, but also those reported by other authors. Particular cases of the proposed model are discussed.Centro de Investigación y Desarrollo en Criotecnología de Alimento

The application of different techniques to determine activated sludge kinetic parameters in a food industry wastewater

In the present work, a continuous-feed system under steady state conditions (classical method) and a respirometric technique based on oxygen consumption measurements, were used to compare microbial parameters using a wastewater model system of a potato processing plant. The effects of the operating conditions in the continuous aerobic reactor on microbial growth and flora composition were also analysed. Continuous-feed experiments allowed for the calculation of the following biodegradation parameters: maximum substrate consumption specific rate (qSmax) = 0.19 mgCOD (mgVSS)-1·h-1, saturation constant (Ks) = 8.3 mgCOD·l-1, biomass yield (YX/S) = 0.61 mgVSS (mgCOD)-1, biomass decay constant (kd) = 0.04·h-1 and maximum oxygen consumption specific rate (qO2max) = 0.03 mgCOD (mgVSS)-1·h-1.The respirometric technique also allowed for the calculation of kinetic parameters. However, these parameters depended on dilution rate (D) and / or on dissolved oxygen concentration (DO). Values of qO2max and Ks increased with D; qO2max ranged between 0.05 and 0.13 mgO2 (mgVSS)-1·h-1 and Ks between 2 and 26 mgCOD·ℓ-1 for D values varying between 0.01 and 0.15·h-1. Microscope observations showed that sludge composition was a function of dilution rate. Low D values (low soluble organic matter (Ss) and high DO concentrations) yielded sludges mainly formed by floc-forming bacteria; high D values (high Ss and low DO concentrations) yielded sludges mainly formed by filamentous micro-organisms. Since the low substrate / biomass ratios used in the respirometric method limit the growth of micro-organisms maintaining the initial physiological state of the original biomass, the observed differences in the respirometric parameters reflected the actual microbial composition.Fil: Contreras, Edgardo Martin. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Bertola, Nora Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; ArgentinaFil: Zaritzky, Noemi Elisabet. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; Argentin

Valor de la tomografía computarizada volumétrica en el estudio de la enfermedad pulmonar obstructiva crónica

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid. Facultad de Medicina. Departamento de Medicina. Fecha de lectura: 13 de abril, 201