1,421 research outputs found
MÉTODOS ESTADÍSTICOS MULTIVARIANTES EN ANTROPOLOGÍA FÍSICA. VARIABLES MÉTRICAS
Furthering our knowledge of interpopulational variability is one important research line in the f ield of Anthropology. Methods based on the statistical treatment of different metric variables have traditionally been used to determine aff inities and similarities among different skeletal series. For comparisons among samples of populations, however, multivariate analyses may supply information that the classic univariate and bivariate statistical methods cannot provide. Such techniques include Principal Component Analysis, Factor Analysis, and Clustering, now commonly used when dealing with metric characters. This study presents a practical example in which a Medieval skeletal series from the Alto Ebro and Alto Duero (northern Spain) is compared with other samples from the Iberian Peninsula and one sample from the North of Africa. Our objective is to provide data that will enhance anthropological understanding of past populations, particularly in terms of interpopulational and intergrupal variability.Profundizar en el conocimiento de la variabilidad interpoblacional es una de las líneas de investigación de la Antropología. Para conocer las af inidades y similitudes entre diversas series esqueléticas, se han empleado tradicionalmente métodos que se basan en el tratamiento estadístico de diferentes variables métricas. Para las comparaciones entre muestras de población se puede recurrir a análisis multivariantes que aportan la información que los métodos estadísticos tradicionales univariantes y bivariantes no pueden proporcionar. Entre las técnicas multivariantes figuran el Análisis de Componentes principales, el Análisis Factorial y el Análisis de Conglomerados (cluster) que son algunas de los más usadas para el tratamiento de caracteres métricos. En el presente trabajo se presenta un ejemplo práctico en el que se comparan una serie esquelética medieval del Alto Ebro y Alto Duero con otras muestras de la Península Ibérica y una del Norte de África. El objetivo es aportar datos para el mejor conocimiento antropológico de las poblaciones del pasado y estudiar la variabilidad interpoblacional e intragrupal
Sustainable one-pot immobilization of enzymes in/on metal-organic framework materials
peer-reviewedThe industrial use of enzymes generally necessitates their immobilization onto solid supports. The well-known high affinity of enzymes for metal-organic framework (MOF) materials, together with the great versatility of MOFs in terms of structure, composition, functionalization and synthetic approaches, has led the scientific community to develop very different strategies for the immobilization of enzymes in/on MOFs. This review focuses on one of these strategies, namely, the one-pot enzyme immobilization within sustainable MOFs, which is particularly enticing as the resultant biocomposite Enzyme@MOFs have the potential to be: (i) prepared in situ, that is, in just one step; (ii) may be synthesized under sustainable conditions: with water as the sole solvent at room
temperature with moderate pHs, etc.; (iii) are able to retain high enzyme loading; (iv) have negligible protein leaching; and (v) give enzymatic activities approaching that given by the corresponding free enzymes. Moreover, this methodology seems to be near-universal, as success has been achieved with different MOFs, with different enzymes and for different applications. So far, the metal ions forming the MOF materials have been chosen according to their low price, low toxicity and, of course, their possibility for generating MOFs at room temperature in water, in order to close the cycle of economic, environmental and energy sustainability in the synthesis, application and disposal life cycle
Teaching and learning mathematics and statistics at an Agricultural Engineering School
This paper focuses on the teaching and learning of mathematical topics at the School of Agricultural Engineering of Barcelona in Spain. The teaching and learning process was hindered by under-achievement, absenteeism and lack of motivation on the student’s side. To overcome such obstacles we decided to set to work a new design for the subjects involved with the help of computer and other technologies. Therefore we devised a methodology based on the use of technical tools aiming at solving standard problems and fostering the communication teacher-student. This paper outlines the activities performed to the purpose, depending on the specific contents of each subject matter and the context where they are conducted. However, the use (and misuse) of technology entails some drawbacks, which can be sorted out by means of other kinds of activities, such as lectures, different types of examination questions or the achievement of a project work. Since the implementation of the sketched methodology absenteeism turns out to decrease, whereas students’ motivation seems to improve. In fact students employ statistical tools more frequently than in previous years to fulfil their final degree project. Likewise this methodology contributes to enhance students’ independent work, which matches perfectly the framework of the European Credit Transfer System.Peer Reviewe
Teaching and learning mathematics and statistics at an agricultural engineering school
Postprint (published version
Computer assisted assessment through Moodle quizzes for calculus in an Engineering Undergraduate Course
The European Higher Education Area (EHEA) furthers a student-centered system based on the student workload required to achieve the objectives of a study program. In the context of EHEA, e-learning tools provide an outstanding opportunity to discuss mathematical activity in the 21st-century classroom. In 2002, the Technical University of Catalonia (UPC) undertook the use of a virtual teaching tool, the virtual campus Atenea. Since 2005 Atenea has been based on Moodle, an open source learning management system designed to help educators create quality online courses and administer learner outcomes. From the wide range of tools offered by Moodle, we are focusing on the quiz module. This module allows the creation of quizzes with different types of question, adapted to the specific objectives to be reached at any step in the teaching-learning process. Moodle quizzes contribute to the development of new strategies not feasible with paper-and-pencil tests. To explore how to apply these new strategies in the development of a substantial bank of quiz questions, we are carrying out projects subsidised by the Institute of Education Sciences of the UPC. This contribution focuses on the assessment of three Moodle quizzes for Calculus topics that were designed to be answered by around 70 first-year students of the School of Civil Engineering (UPC) in the course 2007/2008. In particular, the aims are to analyse students’ answers and to carry out a psychometric analysis to identify the appropriateness of the questions stated in the quizzes.Peer Reviewe
HCT116 cells deficient in p21Waf1 are hypersensitive to tyrosine kinase inhibitors and adriamycin through a mechanism unrelated to p21 and dependent on p53
El pdf del artículo es la versión de autor.-- et al.p21Waf1 (p21) was described as a cyclin-dependent kinase inhibitor, but other p21 activities have subsequently been described, including its ability to inhibit apoptosis in some models. Comparative work on the human colon cancer isogenic cell lines HCT116 and HCT116p21-/- led to the proposal that p21 protects colon cancer cells against apoptosis by genotoxic drugs. We asked whether p21 also protected from cell death induced by non-genotoxic drugs, such as tyrosine kinase inhibitors. We found that p21-deficient cells were dramatically more sensitive towards imatinib and gefitinib than parental cells. Interestingly, HCT116p21-/- also showed higher basal activity of protein kinases as c-Abl, c-Src, and Akt. We generated HCT116p21-/- sublines with inducible p21 expression and found that p21 did not rescue the hypersensitivity to imatinib. Moreover, down-regulation of p21 by enforced c-Myc expression or by p21 siRNA did not sensitize parental HCT116 cells. We found that, in HCT116p21-/- cells, p53 showed higher stability, higher transcriptional activity and phosphorylation in serines associated with p53 activity. Furthermore, silencing of p53 with siRNA and inactivation of p53 with a dominant negative mutant rescued the hypersensitive response to kinases inhibitors, 5-fluorouracil and adriamycin in HCT116p21-/- cells. Consistently, HCT116p53-/- cells are more resistant to imatinib than parental cells, suggesting that imatinib activity is partly dependent on p53 in colon cancer cells. We conclude that high p53 activity, rather than p21 deficiency, is the mechanism responsible for hypersensitivity to drugs of HCT116p21-/- cells. Therefore the role of p21 on apoptosis of HCT116 colon cancer cells should be re-evaluated. © 2008 Elsevier B.V. All rights reserved.N.F. is funded by a predoctoral fellowship from the Spanish Ministry of Education and Science (MEC) and from the University of Cantabria. Work at the laboratory of J.L. is funded by MEC grants SAF2005-00461 and Spanish Ministry of Health and Consume (MSC) grant ISCIII-RETIC-RD06/0020. M.D.D. is funded by MSC grant FIS04-1083, and J.M.P. is funded by grants from Fundación de Investigación Médica Mutua Madrileña and MEC grant SAF2006-00371.Peer Reviewe
A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model
[EN] An implementation and validation of the coupled Sigma-gamma ADF model is presented in this work for reacting Diesel spray CFD simulations under a RANS turbulence modeling approach. An Approximated Diffusion Flamelet (ADF) model Michel et al. (2008) implemented in the OpenFOAM CFD open-source library by Winklinger (2014)15 fed with the spray description, i.e. mixing formation process, provided by the Sigma-gamma Eulerian atomization model Garcia-Oliver et al. (2013). In the present investigation, the Engine Combustion Network Spray A reference configuration is used for validation. Specifically, the model can provide accurate predictions of typical reacting spray metrics, such as the ignition delay and the lift-off length. Moreover, the internal structure is also fairly reproduced in terms of quasi-steady spatial distribution of formaldehyde and OH, related with low and high temperature reactions respectively. Additionally, modeling results have been compared to recent Particle image velocimetry (PIV) measurements Garcia-Oliver et al. (2017) under both inert and reacting conditions. Flow response to heat release is quantitatively predicted by the model, both in terms of local velocity increase as well as radial dilation. The model has been used to understand combustion-induced reduction in entrainment, in particular around the lift-off length location. Flow confinement does not seem to influence the global flame behaviour, even though some changes in the local flow hint can be observed when moving from an open to a closed domain. (C) 2017 Elsevier Ltd. All rights reserved.Authors acknowledge that this work was possible thanks to the Programa de Ayudas de Investigation y Desarrollo (PAID-2013 3198) of the Universitat Politecnica de Valencia. Also this study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF(TRA2014-59483-R) project. Authors thank Gilles Bruneaux from IFPEN for the interesting suggestions and discussions.Pandal-Blanco, A.; García-Oliver, JM.; Novella Rosa, R.; Pastor Enguídanos, JM. (2018). A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model. International Journal of Multiphase Flow. 99:257-272. https://doi.org/10.1016/j.ijmultiphaseflow.2017.10.010S2572729
HPLC–(Q)-TOF-MS-Based Study of Plasma Metabolic Profile Differences Associated with Age in Pediatric Population Using an Animal Model
[EN] A deep knowledge about the biological development of children is essential for appropriate drug administration and dosage in pediatrics. In this sense, the best approximation to study organ maturation is the analysis of tissue samples, but it requires invasive methods. For this reason, surrogate matrices should be explored. Among them, plasma emerges as a potential alternative since it represents a snapshot of global organ metabolism. In this work, plasma metabolic profiles from piglets of different ages (newborns, infants, and children) obtained by HPLC–(Q)-TOF-MS at positive and negative ionization modes were studied. Improved clustering within groups was achieved using multiblock principal component analysis compared to classical principal component analysis. Furthermore, the separation observed among groups was better resolved by using partial least squares-discriminant analysis, which was validated by bootstrapping and permutation testing. Thanks to univariate analysis, 13 metabolites in positive and 21 in negative ionization modes were found to be significant to discriminate the three groups of piglets. From these features, an acylcarnitine and eight glycerophospholipids were annotated and identified as metabolites of interest. The findings indicate that there is a relevant change with age in lipid metabolism in which lysophosphatidylcholines and lysophoshatidylethanolamines play an important role.This research was funded by UPV/EHU (Project GIU16/04) and the Spanish Ministry of Economy and Competitiveness (Project CTQ2013-46179-R)
Reclutamiento y retención de adolescentes en una intervención para prevenir VIH/SIDA
Es importante que toda intervención profesional que
busca modificar conductas que afectan la salud, muestre
su efectividad aplicando una metodología apropiada
que sustente los resultados. En este contexto, el reclutamiento y retención de los participantes es uno de los factores centrales que dan validez a los productos de la intervención. El Programa “Cuídate Promueve tu Salud”,
constituye una experiencia valiosa en donde se mostró
la aplicabilidad exitosa de estrategias relativamente simples
para reclutar y retener participantes.
Toda propuesta de intervención controlada incluye el
plan de reclutamiento y retención de la muestra; sin
embargo, es en la experiencia que éstos toman el contenido
que da validez a la metodología seguida. La sistematización
y la definición de criterios, son las características
que permiten alcanzar calidad, eficiencia y efectividad
en la selección y retención de sujetos participantes
en la investigación. En el Programa “Cuídate”, fue importante decidirnos por reclutar a los adolescentes de las preparatorias de una Universidad Estatal. Esta institución educativa tiene en su alumnado una representación equilibrada de familias de diversos estratos económicos y casi un número igual de hombres y mujeres. Por otro lado, y esto en relación con la retención de sujetos, la estrategia de mantener contacto fue a través de diversos métodos (carta, tarjeta recordatorio y llamada telefónica) a lo largo de la duración de la intervención, fue el factor clave para asegurar el alto porcentaje alcanzado tanto con los adolescentes, como con sus padres
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The genomic diversification of grapevine clones.
BACKGROUND:Vegetatively propagated clones accumulate somatic mutations. The purpose of this study was to better appreciate clone diversity and involved defining the nature of somatic mutations throughout the genome. Fifteen Zinfandel winegrape clone genomes were sequenced and compared to one another using a highly contiguous genome reference produced from one of the clones, Zinfandel 03. RESULTS:Though most heterozygous variants were shared, somatic mutations accumulated in individual and subsets of clones. Overall, heterozygous mutations were most frequent in intergenic space and more frequent in introns than exons. A significantly larger percentage of CpG, CHG, and CHH sites in repetitive intergenic space experienced transition mutations than in genic and non-repetitive intergenic spaces, likely because of higher levels of methylation in the region and because methylated cytosines often spontaneously deaminate. Of the minority of mutations that occurred in exons, larger proportions of these were putatively deleterious when they occurred in relatively few clones. CONCLUSIONS:These data support three major conclusions. First, repetitive intergenic space is a major driver of clone genome diversification. Second, clones accumulate putatively deleterious mutations. Third, the data suggest selection against deleterious variants in coding regions or some mechanism by which mutations are less frequent in coding than noncoding regions of the genome
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