4,043 research outputs found

    In vitro approach to the study of chronic exposure to low doses of x-rays

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    El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Fil: Ponzinibbio, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Seoane, Analia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin

    International migration and its consequences on the social construction of gender: a case study of a Mexican rural town

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    This thesis is the result of ethnographic research conducted in a sending community in the state of Hidalgo, Mexico. This study calls into question the stereotypical view of Mexican women as passive and traditional. There are several conclusions reached during this study. First, the results reject Menjivar's (1999) and Levitt's (1998) argument. In the community studies, an unfulfilled economic or emotional absence encourages women to challenge the system of practice of Nurangi (participation in the labor force) even in the absence of a migration experience. Second, the analysis shows that contrary to our hypothesis, the physical absence of the male is not a trigger mechanism for women's participation in the labor force. Third, women from both migrant and non-migrant related groups have increased their human capital. However, migrant and non-migrant related women who participated in market activities not only expanded their human capital but also gained an economic and emotional benefit. Finally, the interviews have also shown that contrary to some literature that views Mexican women as passive and subordinate agents, the women in the Nurangi community are active agents, and what is sometimes perceived as a static gender division of labor is rather a fluid

    ETCS Experiences in Zoology: Under and Postgraduate Courses

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    Evaluación del idioma inglés como competencia transversal en las asignaturas de matemáticas en la educación superior

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    Entre las competencias clave que la Unión Europea ha definido se encuentran la comunicación en lenguas extranjeras y la matemática. El conjunto de todas estas competencias clave representan una combinación de conocimientos, habilidades y actitudes consideradas necesarias para la realización y el desarrollo personal, la ciudadanía activa, la inclusión social y el empleo. La evaluación juega un papel decisivo en el diagnóstico de la calidad y la relevancia de las competencias adquiridas. El estándar internacional (MCER) que define la competencia lingüística y describe de forma integradora lo que tiene que conocer un estudiante de lengua extranjera con el fin de utilizarla para comunicarse, define los niveles de dominio de la lengua que permiten comprobar el avance del alumno en cada fase del aprendizaje y a lo largo de su vida. Sin embargo, no se ha diseñado un método de evaluación de la competencia de inglés como competencia transversal en las asignaturas de matemáticas en la educación superior, que permita medir la capacidad de los alumnos para aplicar sus conocimientos de la lengua inglesa de forma contextualizada. En este trabajo se analiza la competencia genérica de la lengua inglesa con fines académicos (IFA) y su evaluación. PALABRAS CLAVE: Evaluación, competencia genérica, IFA inglés con fines académicosPostprint (published version

    Real-time audio interaction in serious games for music learning

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    In this LBD, we present several Apps for playing while learning music or for learning music while playing. The core of all the games is based on the good performance of the real-time audio interaction algorithms developed by the ATIC group at Universidad de Ma ́laga (SPAIN).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been funded by the Ministerio de Econom ıa y Competitividad of the Spanish Government under Project No. TIN2013-47276-C6-2-R and by the Junta de Andalucía under Project No. P11-TIC-7154

    Clinkering and hydration study of non-active and active Belite-Alite-Ye'elimite (BAY) cements

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    The aim of AIM is to promote industry-driven, interdisciplinary research in material science and engineering in order to provide leading-edge, sustainable solutions to the challenges facing engineers in today’s changing society and environment. http://www.ucl.ac.uk/aim/conference-info/37ccsThe manufacturing process of ye'elimite rich cements emit about 15-37% less CO2 to the atmosphere than OPC. Cements that contain belite, ye’elimite and ferrite, known as BYF cements, are promising eco-friendly binders. However, belite, their main phase, shows a slow hydrating behaviour; therefore the corresponding mortars present lower mechanical strengths than OPC at early ages. To solve this problem, BYF clinkers can be activated by: i) forming alite jointly with belite and ye’elimite during clinkering, known as BAY clinkers. The alite and ye’elimite reaction with water should develop high mechanical strengths at early ages, besides, belite contributes to later curing times. ii) A second activation is based on the stabilisation of alpha forms of belite by dopants. The objective of this work is to obtain two types of BAY clinkers (standard and active BAY) using CaF2 as mineraliser and borax as dopant agent to stabilize alpha forms of belite phase. After that, anhydrite was added as sulphate source to obtain the corresponding cements. The hydration behaviour of these cements has been studied through rheological and x-ray diffraction measurements, the latter combined with Rietveld quantitative phase analysis. In addition, mechanical and dimensional properties of BAY mortars are also presented and discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Advanced synchrotron studies of ye'elimite-based cement pastes

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    Synchrotron characterization techniques [1] are being used to study Portland-based cements and recently also CSA and related cements. A key property of these techniques is that they do not require sample preparation, so the microstructures of the pastes can be preserved. The classical application of synchrotron tools is powder diffraction used to determine the crystalline phase content evolution with hydration including the overall amorphous fraction. Furthermore, other most advanced techniques are being applied to ye'elimite-containing pastes such as i) Total Scattering Synchrotron Powder Diffraction (TS-SXPD), and ii) Ptychographic Synchrotron X-ray Computed Tomography (PSXCT). All these applications will be reviewed here. TS-SXPD data coupled with the Pair Distribution Function (PDF) analysis methodology [2] allows having a better insight about the nanocrystalline/amorphous atomic arrangements in the gels. It has been very recently shown that nanogibbsite with very small particles, 3nm, is the main constituent of ye'elimite-gypsum hydration paste [2]. Nanogibbsite particles being smaller than those originated from the hydration of monocalcium aluminate. In addition, PSXCT is a tomographic technique that profits from the partly coherent nature of the synchrotron beam to provide better (smaller) resolution, which can be lower than 100 nm. It also provides the mass densities if the chemical stoichiometries are known. This technique has been applied to ye'elimite hydration to determine the microstructure and chiefly the bulk densities of nanogibbsite [3]. The microstructure evolution at early age was also followed [4]. Figure 1 shows an example of a slide of the electron density tomogram for a ye'elimite paste at 8 days of hydration and the corresponding histogram for the full volume with all phases identified.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.This work has been supported by Spanish MINECO through BIA2014-57658-C2 and BIA2017-82391-R, which are co-funded by FEDER

    Early hydration study of standard and doped Alite-Belite-Ye’elimite (ABY) cements through Synchrotron Radiation

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    The manufacturing of ye'elimite-rich cements releases from 15 to 37%, depending on their composition, less CO2 to the atmosphere than ordinary Portland cement (OPC). BYF cements containing belite, ye’elimite and ferrite as main crystalline phases, are promising eco-friendly binders. Nevertheless, belite, its main phase, shows a slow hydrating behaviour and the mechanical strengths are lower than OPC at early ages. Some alternatives to solve this problem are: i) forming alite jointly with belite and ye’elimite during clinkering, Alite Belite Ye’elimite (ABY) clinkers. The hydration of alite and ye’elimite would develop high mechanical strengths at early ages, and belite contributes to later curing times; ii) a second alternative is the stabilisation of alpha forms of belite using dopants such as boron named here after dABY. In this work, two different types of ABY clinkers (standard and doped) have been prepared and characterized to understand their different hydration mechanisms at the same water-to-cement (w/c) ratio. The clinkers have been prepared using CaF2 and ZnO as mineralizers, and borax as dopant agent to stabilize alpha forms of belite (’H-C2S). Afterwards, 14 wt% of anhydrite (as soluble sulphate source) was added to prepare the corresponding cements. Finally, the hydration study was performed at w/c ratio of 0.5. Here, an in-situ hydration study using synchrotron X-ray powder diffraction (SXRPD) for the first 14 hours of hydration is reported. Moreover, these results will be combined with the ex-situ laboratory X-ray powder diffraction study (LXRPD) at 1 day of hydration and calorimetric results. Rietveld quantitative phase analysis has been used to establish the phase evolution across the time.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO ( BIA2017-82391-R), co-funded by FEDER, and I3 [IEDI-2016-0079]

    Water-to-cement ratio influence on low-carbon cements performances

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    Portland Cement (PC) is the most important active ingredient in most of the construction concrete. However, the PC production is associated with a high carbon dioxide release (around 1 ton of CO2 per ton of PC). One approach to reduce CO2 emissions consists on the reformulation of the clinker with less calcite demanding phases, such as, belite rich clinkers. The drawback of this kind of clinkers is the low reactivity of belite (beta-belite). In order to compensate this problem, belite rich clinkers can be prepared with ye’elimite and ferrite or with alite [known as belite-ye’elimite-ferrite (BYF) and belite-alite-ye’elimite (BAY), respectively]. In addition, it can be improved by using a high reactive belite polymorph, such as alpha-belite. In this work, the hydration and mechanical behaviour of BYF and BAY cements (with beta and/or alpha-belite) with different water-to-cement ratios have been studied. The clinkers were produced using natural raw materials, and were mixed with anhydrite (CaSO4) to prepare the corresponding cements. At early ages, the main hydration products of these cements were ettringite, calcium monosulfoaluminate and amorphous aluminium hydroxide. At later ages, stratlingite, katoite and amorphous C-S-H were found. The compressive strength values of the corresponding mortars were correlated with the mineralogy evolution of the pastes (mainly obtained by XRD and TGA).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. I3-Ramón y Cajal Universidad de Malag

    Modeling spectral changes in singing voice for pitch modification

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    We present an advanced method to achieve natural modifications when applying a pitch shifting process to singing voice by modifying the spectral envelope of the audio ex- cerpt. To this end, an all-pole spectral envelope model has been selected to describe the global variations of the spectral envelope with the changes of the pitch. We performed a pitch shifting process of some sustained vowels with the envelope processing and without it, and compared both by means of a survey open to volunteers in our website.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been funded by the Ministerio de Economía y Competitividad of the Spanish Government under Project No. TIN2013-47276-C6-2-R and by the Junta de Andalucía under Project No. P11-TIC-7154
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