1000 resultados para CALIDAD TOTAL


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A sensitive and simple system was proposed for the in situ measurement of total aldehyde in outdoor or indoor ambient. The method is based on the use of a reagent drop as an useful interface to preconcentrate the sample prior to determination of total aldehyde as formaldehyde. The drop is formed at the tip of a cylindrical tube that contains two optical fibers placed on opposite sides and in contact with the reagent solution. One optical fiber carries the red light to the drop form a light emitting diode (LED). The transmitted light is measured by a second optical fiber/photodiode system. The analytical signal is read and converted into absorbance. The reagent solution of 3-methyl-2-benzothiazoline hydrazone (MBTH) forms a blue cation during reaction with formaldehyde that can be measured at 660 nm. Some aspects of kinetics reaction formation of dye were reevaluated. The formaldehyde reacts with MBTH and forms the azine in about 12 min. The oxidation of MBTH by Fe (III) and the formation of dye requires 3 min. The absorbance of the reagent drop is proportional to the sampling time and to the analyte concentration. The absorbance signal increases with increased sample gas flow until a maximum is reached then decreases until it forms a plateau. The proposed method was evaluated using both outdoor and indoor samples, and it was shown to viable provide an accurate measure of total aldehyde.

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Este trabajo de investigación abarca el estudio, implementación y evaluación de diferentes herramientas, metodologías y procesos para la producción de software libre en el campo del desarrollo rápido de aplicaciones (RAD, precursor de metodologías ágiles como Scrum).

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Infection is one of the most serious complications after total knee arthroplasty (TKA). The current incidence of prosthetic knee infection is 1-3%, depending on the series(.) For treatment and control to be more cost effective, multidisciplinary groups made up of professionals from different specialities who can work together to eradicate these kinds of infections need to be assembled. About the microbiology, Staphylococcus aureus and coagulase-negative staphylococcus were among the most frequent microorganisms involved (74%). Anamnesis and clinical examination are of primary importance in order to determine whether the problem may point to a possible acute septic complication. The first diagnosis may then be supported by increased CRP and ESR levels. The surgical treatment for a chronic prosthetic knee infection has been perfectly defined and standardized, and consists in a two-stage implant revision process. In contrast, the treatment for acute prosthetic knee infection is currently under debate. Considering the different surgical techniques that already exist, surgical debridement with conservation of the prosthesis and polythene revision appears to be an attractive option for both surgeon and patient, as it is less aggressive than the two-stage revision process and has lower initial costs. The different results obtained from this technique, along with prognosis factors and conclusions to keep in mind when it is indicated for an acute prosthetic infection, whether post-operative or haematogenous, will be analysed by the authors.

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Larnellarins are a group of marine natural products isolated from the prosobranch mollusc Lamellaria sp., the ascidian Didemnum sp., and the sponge Dendrilla Cactos. Several of them exhibit interesting biological activities. Natural as well as synthetic lamellarins should be excellent candidates for the development of new drugs due to their unique skeletal structure and their important biological activities especially as antitumor agents. Lamelarin O has been recently characterized as a topoisomerase 1-targeted anti tumor agent. A variety of synthetic approaches have been developed for this family of alkaloids. Herein we describe a new route to the synthesis of Lamellarin D, from a methyl 2-pyrrolecarboxylate. Transformation of the starting material into the scaffold, a substituted 5,6-dihydropyrrolo (2,l ­a)isoquinoline (5,6-DHPl), was afforded by N-alkylation followed by intramolecular Heck cyclization. From this scaffold the synthetic strategy is based on two sequential regioselective bromination!Suzuki cross-coupling reactions which permitted the introduction of differently substituted aryl groups on positions 1 and 2 followed by oxidation, deprotection, and lactonization.

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Quality of life is increasingly becoming a concept researched empirically and theoretically in the field of economics. In urban economics in particular, this increasing interest stems mainly from the fact that quality of life affects urban competitiveness and urban growth: research shows that when households and businesses decide where to locate, quality of life considerations can play a very important role. The purpose of the present paper is to examine the way economic literature and urban economic literature in particular, have adopted quality of life considerations in the economic thinking. Moreover, it presents the ways various studies have attempted to capture the multidimensional nature of the concept, and quantify it for the purposes of empirical research. Additionally we focus on the state of the art in Spain. Looking at the experiences in the last years we see very important possibilities of developing new studies in the field.

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This paper investigates the extent to which the gap in total factor productivity between small and large firms is due to differences in the endowment of factors determining productivity and to the returns associated with these factors. We place particular emphasis on the contribution of differences in the propensity to innovate and in the use of skilled labor across firms of different size. Empirical evidence from a representative sample of Spanish manufacturing firms corroborates that both differences in endowments and returns to innovation and skilled labor significantly contribute to the productivity gap between small and large firms. In addition, it is observed that the contribution of innovation to this gap is caused only by differences in quantity, while differences in returns have no effect; in the case of human capital, however, most of the effect can be attributed to increasing differences in returns between small and large firms.

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The monitoring of the pollution status of the Brazilian coast is hampered by the lack of a consistent environmental indicator. We propose Hg as an environmental proxy to anthropogenic pollution of coastal regions due to its absence in the Brazilian geology, its ubiquity in anthropogenic effluents, and its toxicity. Available data suggest Hg "backgrounds" in coastal sediments of 1-10 ng g-1, in the East and 15-30 ng g-1 in the South. We suggest short sediment cores to establish these values estimating a geo-accumulation index to compare all areas. The distribution of index values showed the majority of southern coast at least moderately contaminated whereas many eastern areas are still pristine.

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Thermospray flame furnace Atomic Absorption Spectrometry (TS-FF-AAS) was used for the total determination of Cd, Pb and Zn in fresh water and seawater samples at µg L-1 levels, and in marine sediment samples at µg g-1 levels. Using a sample loop of 50 µL and a peristaltic pump the samples were transported into the metallic tube placed over an air/acetylene flame, through a ceramic capillary (o.d. = 3.2 mm) containing two parallel internal orifices (i.d = 0.5 mm). The detection limits determined for Cd, Pb and Zn using a synthetic water matrix (2.5% m/v NaCl, 0.5% m/v MgCl2 and 0.8% m/v CaCl2) were 0.32 µg L-1; 2.6 µg L-1 and 0.21 µg L-1 respectively. The methodology by TS-FF-AAS was validated by determination of Cd, Pb and Zn in certified reference materials of water and marine sediment, and the t-test for differences between means was applied. No statistically significant differences were established in fresh water and seawater (p>0.05), whereas differences became apparent in marine sediment (p<0.03).

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La calidad de vida en la población universitaria adquiere una especial importancia ya que permite obtener información sobre las condiciones de vida de los universitarios y, sobre todo, de cómo éstos las perciben. Objetivo: Evaluar la calidad de vida de los universitarios que cursan estudios en ciencias de la salud y su relación con diferentes factores tales como: hábitos de vida, parámetros antropométricos y la influencia de las distintas variables sobre su percepción. Material y Método: Estudio transversal de una muestra de 1.753 estudiantes de ciencias de la salud de nueve universidades españolas con diseño muestral aleatorio y estatrificado según curso y facultad al que se le aplicó un cuestionaro ad hoc que recogía todas las variables a estudio. Resultados: La calidad de vida percibida por los participantes fue Me = 75. Los factores explorados de la calidad de vida se co-relacionaron significativamente con la percepción global de calidad de vida de los estudiantes (p<0,001). Se establecieron 3 dimensiones y el impacto de cada una de ellas sobre la percepción de calidad de vida global fue p<0,001. Los varones percibieron mejor calidad de vida que las mujeres y también los estudiantes con menor Índice de Masa Corporal (IMC). Conclusión: Los universitarios son una población clave para realizar actividades de promoción y prevención de la salud por lo que resulta necesario crear mejores infraestucturas y recursos educativos para mejorar la CV y fomentar hábitos y estilos de vida saludable con especial atención en la alimentación y la realización de una adecuada actividad física.

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El presente informe tiene por objeto exponer los resultados correspondientes al segundo año de andadura de la Cátedra UB – Fundación Adecco para la Integración Laboral de Personas con Discapacidad (http://www.ub.edu/catedrainlab/).