999 resultados para Echeverria, Esteban
Resumo:
Maintaining and acquiring the pluripotent cell state in plants is critical to tissue regeneration and vegetative multiplication. Histone-based epigenetic mechanisms are important for regulating this undifferentiated state. Here we report the use of genetic and pharmacological experimental approaches to show that Arabidopsis cell suspensions and calluses specifically repress some genes as a result of promoter DNA hypermethylation. We found that promoters of the MAPK12, GSTU10 and BXL1 genes become hypermethylated in callus cells and that hypermethylation also affects the TTG1, GSTF5, SUVH8, fimbrin and CCD7 genes in cell suspensions. Promoter hypermethylation in undifferentiated cells was associated with histone hypoacetylation and primarily occurred at CpG sites. Accordingly, we found that the process specifically depends on MET1 and DRM2 methyltransferases, as demonstrated with DNA methyltransferase mutants. Our results suggest that promoter DNA methylation may be another important epigenetic mechanism for the establishment and/or maintenance of the undifferentiated state in plant cells.
Resumo:
The Erasmus Mundus Master in Quality in Analytical Laboratories (EMQAL) is a two-year Joint Master Degree. The course is funded by the European Commission through the Erasmus Mundus Programme, providing a number of attractive scholarships for European and non-European students. EMQAL prepares professionals for analytical laboratories, focusing on laboratory management and quality systems, along with complementing their technical knowledge. The EMQAL aims at training students in the most relevant issues concerning quality systems and management in analytical laboratories, and to become an expert in: Quality management, Analytical methods and Data Analysis. EMQAL promotes mobility. The students will attend one academic year of lectures in one of the European universities of the EMQAL consortium, and a 12 months master thesis at other European university, with the possibility to spend three-months in one of the non-EU partners. The language of instruction and examination is English. Further information is available at www.emqal.org.
Resumo:
Capítol 19 del llibre 'Conceptos y técnicas en ecología fluvial' que es refereix a les relacions tròfiques en l'ecosistema fluvial
Resumo:
One of the techniques used to detect faults in dynamic systems is analytical redundancy. An important difficulty in applying this technique to real systems is dealing with the uncertainties associated with the system itself and with the measurements. In this paper, this uncertainty is taken into account by the use of intervals for the parameters of the model and for the measurements. The method that is proposed in this paper checks the consistency between the system's behavior, obtained from the measurements, and the model's behavior; if they are inconsistent, then there is a fault. The problem of detecting faults is stated as a quantified real constraint satisfaction problem, which can be solved using the modal interval analysis (MIA). MIA is used because it provides powerful tools to extend the calculations over real functions to intervals. To improve the results of the detection of the faults, the simultaneous use of several sliding time windows is proposed. The result of implementing this method is semiqualitative tracking (SQualTrack), a fault-detection tool that is robust in the sense that it does not generate false alarms, i.e., if there are false alarms, they indicate either that the interval model does not represent the system adequately or that the interval measurements do not represent the true values of the variables adequately. SQualTrack is currently being used to detect faults in real processes. Some of these applications using real data have been developed within the European project advanced decision support system for chemical/petrochemical manufacturing processes and are also described in this paper
Resumo:
The effect of operational variables and their interaction in TPR profiles was studied using a fractional factorial experimental design. The heating rate and the reducing agent concentration were found to be the most important variables determining the resolution and sensitivity of the technique. They showed opposite effects. Therefore, they should be manipulated preferentially in order to obtain optimized TPR profiles. The effect of sample particle size was also investigated. The tests were carried out within a Cu/Zn/Al2O3 catalyst used for the water-gas shift reaction that presented two distinct species of Cu2+ in TPR profiles.
Resumo:
The reduction kinetics of a CuO/ZnO/Al2O3 catalyst by hydrogen was investigated isothermally and by temperature programmed reduction (TPR). Two reducible Cu2+ species were detected; the first one was identified as CuO bulk and the other as Cu2+ strongly interacting with alumina, possibly in the form of copper aluminate. The activation energies for the reduction of these two species were 60 and 90 kJ mol-1, respectively, and the reaction order with respect to hydrogen was one. The isothermal reduction data showed that the isotropic growth model is the most appropriate to describe the reaction rate data for both Cu2+ species.
Resumo:
The thesis or hypothesis of this paper is that the multiple connections of explicit andimplicit life styles foster the construction of hybrid, multiple or complex identities. Wemean by hybrid identities the confluence of multiple identifications in the personalbiography. If the globalization and cultural diversity are the fundamental forms ofglobal life, the mobility is its principal ingredient. We describe different cultural traitsin Chiapas. Internet, migration to United States, or the North American Free TradeAgreement (NAFTA), between North America, Canada, and Mexico, were hybridizedwith the heterogeneity of identity (ethnic, linguistic, and religious). It is discussed thesocial and political consequences of the hybrid contemporary societies
Resumo:
L'Espai Europeu d'Educació Superior s'ha convertit en un repte, un desafiament que implica assolir una convergència de titulacions universitàries equivalents. Per això es requereix una modificació del tradicional ensenyament, en el nostre cas, de la psicologia. En aquest article s'examina l'ensenyament de la psicologia al Institute of Psychological Sciences de la Universitat de Leeds (metodologia docent; avaluació i contingut curricular)
Resumo:
El estudio utiliza un diseño transversal en el campo de la percepción de la vitalidad etnolingüística. Es el primero que compara la percepción de la vitalidad etnolingüística, así como los factores asociados, entre adultos jóvenes y adultos, en relación con los grupos castellanohablantes y catalanohablantes de la Comunidad Autónoma de Cataluña. Para ello, se aplicó el 'Cuestionario de vitalidad etnolingüística subjetiva' (CVS) a una muestra de 527 participantes, 268 jóvenes y 259 adultos, de los cuales se seleccionó una submuestra de individuos que tenían el catalán como lengua materna y se identificaban como catalanes (n=301). En ambas muestras se aduce una tendencia a descriminar favorablemente la vitalidad percibida por el grupo catalán, aspecto que se acentúa significativa en el grupo de jóvenes estudiados en relación al grupo de edad de los adultos. Se discuten los resultados según las repercusiones teóricas y pragmáticas de los estudios realizados en el ámbito de la comunicación intergrupal
Resumo:
Una de les fites psicològiques més rellevants de l’edat infantil (0-6 anys) és l’anomenada ‘comprensió social’, és a dir, el conjunt de processos que permeten entendre, interpretar i predir el comportament de les persones basant-se en estats intencionals com creure, pensar, desitjar o témer (Carpendale i Lewis, 2006)
Resumo:
Este trabajo pretende, en primer lugar, ilustrar empíricamente las características de las nuevas ecologías de aprendizaje de los estudiantes mediante el análisis pormenorizado de cuatro alumnos de cuarto de la ESO durante una semana de sus vidas. En segundo lugar, analizar los perfiles personales de dichos alumnos desde el análisis de su identidad aprendiz; cómo integran su yo de estudiante en su vida cotidiana y qué posturas sostienen en relación a la escuela y al papel que juega tanto en su vida presente como en su proyecto de vida futura
Resumo:
In this article we present a qualitative study conducted with six indigenous and six mestizos from Intercultural University of Chiapas. The aim of the study is to exemplify the mutual perception between different ethno-linguistic groups, as well as the possible change occurred after the admission to the University. That is, opinions about the other group after and before entering the University. We conclude that a higher education intercultural model can promote mutual understanding and relationship between indigenous and mestizos and thus combat prejudices and stereotypes
Resumo:
This study explored the ethnic identity among 331 emerging adults (144 mestizos and 187 indigenous) from the Intercultural University of Chiapas (México). Scholars suggest that ethnicity is much more salient for ethnic minority adolescents than for adolescents who are members of the ethnic majority. Our aim was to compare the results of the Multigroup Ethnic Identity Measure (MEIM) between the majority ethnic group and the minority group studied. Specifically, the following hypothesis was examined: adolescents who are members of the ethnic minority group (indigenous) will score significantly higher on ethnic identity than adolescents who are members of the ethnic majority group (mestizos). The results supported these hypothesis. We suggest that the effect of an intercultural educative model could explain these results
Resumo:
El propósito de este trabajo es realizar una puesta al día sobre las relaciones entre el desarrollo del lenguaje y el desarrollo de la Teoría de la Mente. Entre las hipótesis propuestas para conceptualizar dichas relaciones, realizamos un examen más exhaustivo de aquellos modelos que apoyan una implicación directa entre lenguaje y Teoría de la Mente. En este contexto, en primer lugar subrayamos la necesidad de ampliar dicha noción para incluir habilidades anteriores y posteriores a la comprensión de la falsa creencia. En segundo lugar, examinamos las diferentes hipótesis acerca de los aspectos del lenguaje más vinculados al desarrollo sociocognitivo, y las principales evidencias empíricas que las sustentan. Finalmente, discutimos un modelo de causalidad recíproca donde los vínculos entre lenguaje y Teoría de la Mente variarán según el momento del desarrollo considerado