496 research outputs found

    El entorno, una herramienta did?ctica para desarrollar el pensamiento y la competencia cient?fica en los ni?os y ni?as de 5 a 7 a?os

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    214 p. Recurso Electr?nicoEl presente trabajo investigativo se llev? a cabo en una instituci?n educativa del municipio de Pereira, en donde se observaron e intervinieron ni?os y ni?as de 5 a 7 a?os desde el desarrollo del pensamiento cient?fico, partiendo de una caracterizaci?n de los estudiantes, evidenciando que los estudiantes no se planteaban, ni les planteaban propuestas para que ellos construyeran sus propios conceptos partiendo de la experiencia; falencia que se ten?a en los procesos de construcci?n de pensamiento por parte de los ni?os, que buscan el conocimiento de su entorno a trav?s del m?todo experimental. La meta del proyecto es favorecer a los educandos en su proceso de formaci?n, partiendo de los conocimientos previos e involucrarlos en la construcci?n del pensamiento cient?fico, en donde se pretende potencializar las habilidades y competencias que les brinde la capacidad de saber, saber hacer y poder hacer en su entorno y este se d? a trav?s de la investigaci?n acci?n-participaci?n, por medio del cual se dio origen a un Proyecto Pedag?gico de Aula, cuyo eje articulador de todo el proceso de formaci?n cient?fica fue el mariposario escolar, generando un espacio de aprendizaje significativo en el que los ni?os est?n en la posibilidad de hacer ciencia mediante la manipulaci?n, experimentaci?n, hip?tesis y conclusiones que obtiene de ser actor protagonista de su propio proceso. Uno de los prop?sitos del trabajo es organizar un ambiente de aprendizaje que fuera significativo para los educandos basado en la observaci?n, formulaci?n de hip?tesis, experimentaci?n y la conclusi?n, es decir el pensamiento cient?fico permitiendo a su vez buscar la manipulaci?n de elementos del entorno, vivencias y aplicaci?n de saberes previos, para poder as? generar una comunicaci?n asertiva donde las conclusiones se dieran a partir de los procesos desarrollados. Palabras Clave: entorno, pensamiento cient?fico, m?todo cient?fico, creatividad, experimentaci?n, conocimiento com?n, conocimiento cient?fico.Pedagogical project in a classroom took place in an institution educational of the municipality of Pereira, where is observed e intervened children and girls from 5 to 7 years from the development about scientific thought, starting of a characterization of them students where is showed the flaw that is had in them processes of construction of thought from the children in the knowledge about their environment through the medium experimental i.e. not raised proposals so that they build their own concepts based on their experience. The project?s goal is to assist learners in their learning process on the basis of previous knowledge and engage them in the construction of scientific thinking where is intended to enhance the skills and competencies that to deliver the ability to know, do, and can do in their environment and this is given through the action - participation research whereby gave rise to the school butterfly as the articulator axis of the entire training process scientific, generating a space of learning significant in which them children are in the possibility of make science through the manipulation, experimentation, hypothesis and conclusions that obtains of be actor protagonist of its own process. Also it had got organize an environment significant of learning, based us in observation, formulation, hypothesis, experimentation and finally the conclusion, to its time it manipulation of elements of this environment, experiences and knowledge previous, reaching thus to generate a communication assertive where each an of them parts presents their questions and their conclusions starting from them processes developed. KeyWords: environment, scientific, thinking, scientific method, creativity, experimentation, common knowledge, scientific knowledge

    Las guardianas de la lengua: mujeres indígenas y educación intercultural bilingüe en Ecuador

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    El presente documento propone ahondar en la comprensión de las relaciones que existen entre la demanda del derecho a la educación intercultural bilingüe en el Ecuador desde la década de los cuarenta, y el nacimiento y consolidación de organizaciones y liderazgos de mujeres indígenas que constituyen una sociabilidad emergente desde lo que entendemos como una suerte de feminismo práctico-comunitario-anticapitalista. En primera instancia, con el fin de enmarcar nuestra discusión y abrir el debate, se presentarán algunas relaciones conceptuales posibles entre género, feminismos e interculturalidad. Posteriormente, se presentará una tentativa de genealogía de la resistencia de las mujeres indígenas en Ecuador para dar cuenta del lugar de las mujeres en la historia de las luchas indígenas en el país, haciendo énfasis en la agencia encaminada hacia la educación propia, intercultural y bilingüe. En un tercer momento, analizaremos la política pública educativa de la última década con relación a las Escuelas del Milenio y daremos ejemplos de cómo las mujeres indígenas del Cañar han mantenido las Escuelas Comunitarias como proceso de resistencia en la estela de las luchas históricas de las mujeres indígenas del Ecuador. Finalmente, a manera de conclusión, daremos cuenta de las potencialidades y retos para un feminismo (práctico-comunitario-anticapitalista) indígena en Ecuador

    Al2O3-3YTZP-Graphene multilayers produced by tape casting and spark plasma sintering

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    This work aims to establish a colloidal route to obtain laminates of alumina zirconia combining layers with and without graphene. Green tapes of alumina, alumina with 5 vol.% of 3Y-TZP and alumina with 5 vol.% of 3Y-TZP and graphene-oxide (2 vol.%) were obtained by aqueous tape casting. It is possible to design materials for different structural applications with a controlled microstructure with a high number of different layers. The tapes were punched into 20-mm discs, joined to form laminates alternating up to 18-layers, and sintered in one-step by spark plasma sintering (SPS) at 1400 degrees C. It has demonstrated that there is a significant graphite diffusion provoked by the required graphite holders into the SPS-furnace. Dense laminates with layer thicknesses similar to 100 mu m and good cohesion between layers were obtained. Nanoindentation results showed that hardness and elastic modulus values were higher than 27 GPa and 300 GPa, respectively, and similar for all layers. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.This work has been supported by Spanish Ministry of Economy and Competitiviness (MAT2012-31090). A. S. A. Chinelatto thanks to CAPES - Programa Ciencias sem Fronteiras (Brazil) for the concession of a fellowship for post-doctoral sabbatical grant in ICV-CSIC, Spain. A. Borrell, acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva contract (JCI-2011-10498) and the Generalitat Valenciana by the financial support for the BEST/2012/302 grant. Authors thank to Nanoinnova Technologies (Spain) for supplying the graphene oxide and helpful discussions.Rincón, A.; Moreno, R.; Chinelatto, ASA.; Gutierrez-Gonzalez, CF.; Rayón Encinas, E.; Salvador Moya, MD.; Borrell Tomás, MA. (2014). Al2O3-3YTZP-Graphene multilayers produced by tape casting and spark plasma sintering. Journal of the European Ceramic Society. 34(10):2427-2434. https://doi.org/10.1016/j.jeurceramsoc.2014.02.011S24272434341

    A quantitative PCR approach for determining the ribosomal DNA copy number in the genome of Agave tequila Weber

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    Background: Agave tequilana has a great economic importance in Mexico in order to produce alcoholic beverages and bioenergy. However, in this species the structure and organization of the rDNAs in the genome are limited, and it represents an obstacle both in their genetic research and improvement as well. rDNA copy number variations per eukaryotic genome have been considered as a source of genetic rearrangements. In this study, the copy number of 18S and 5S rDNAs in the A. tequilana genome was estimated, and an absolute quantitative qPCR assay and genome size was used. In addition, an association between the rDNAs copy number and physical mapping was performed to confirm our results. Results: The analysis were successfully applied to determine copy number of 18S and 5S rDNAs in A. tequilana genome, showing high reproducibility with coefficient of variation (CV) values of 0.014\u20130.0129%, respectively. A variation of 51 times in the copy number the 18s regarding 5s rDNA was found, thus contributing to genome size of 1.47 and 8.38 7 10-3%, respectively. Similarly, data show a linear relationship (R [2] = 0.992) between rDNA copy number and the detected signals for each of the loci by FISH. The comparison of the rDNA copy number of agave showed differential relationship with other organisms and it may be due to evolutionary ecology. Conclusions: Results show that the proposed method a) can correctly detect the rDNA copy number, b) could be used as species-specific markers and c) might help in understanding the genetic diversity, genome organization and evolution of this species

    Desarrollo y validación de un método multiresiduo para el análisis de plaguicidas en miel por UFLC-MS

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    Se desarrolló un método para la determinación de residuos de plaguicidas en miel de abejas mediante cromatografía líquida ultra rápida acoplada a espectrometría de masas (cuádruplo sencillo). Se partió del método QuEChERS, evaluando las siguientes variables: (i) cantidad de muestra, (ii) tipo de sal para el control de pH, (iii) valor de pH del buffer y (iv) mezclas de limpieza. Adicionalmente y con el propósito de demostrar la confiabilidad del método, se evaluaron diferentes parámetros como exactitud, límites de detección y cuantificación, linealidad y selectividad. Los resultados mostraron que, mediante las modificaciones realizadas, se logró obtener un método más selectivo y se mejoró la exactitud de 19 plaguicidas respecto al método QuEChERS original. Por otro lado, mediante el proceso de validación, se encontró que el método es apto para el análisis de 50 plaguicidas (de 56 que se emplearon). Se obtuvieron porcentajes de recuperación entre el 70 y 120% y coeficientes de variación inferiores al 15%.A method for the determination of pesticide residues in honey by ultra fast liquid chromatography coupled with mass spectrometry was developed. For this purpose, different variations of the QuECHERS method were performed: (i) amount of sample, (ii) type of salt to control pH, (iii) buffer pH, and (iv) different mixtures for cleaning-up. In addition, to demonstrate that the method is reliable, different validation parameters were studied: accuracy, limits of detection and quantification, linearity and selectivity. The results showed that by means of the changes introduced it was possible to get a more selective method that improves the accuracy of about 19 pesticides selected from the original method. It was found that the method is suitable for the analysis of 50 pesticides, out of 56. Furthermore, with the developed method recoveries between 70 and 120% and relative standard deviation below 15% were found

    Molecular mechanism for the subversion of the retromer coat by the Legionella effector RidL

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    Microbial pathogens employ sophisticated virulence strategies to cause infections in humans. The intracellular pathogen Legionella pneumophila encodes RidL to hijack the host scaffold protein VPS29, a component of retromer and retriever complexes critical for endosomal cargo recycling. Here, we determined the crystal structure of L. pneumophila RidL in complex with the human VPS29?VPS35 retromer subcomplex. A hairpin loop protruding from RidL inserts into a conserved pocket on VPS29 that is also used by cellular ligands, such as Tre-2/Bub2/Cdc16 domain family member 5 (TBC1D5) and VPS9-ankyrin repeat protein for VPS29 binding. Consistent with the idea of molecular mimicry in protein interactions, RidL outcompeted TBC1D5 for binding to VPS29. Furthermore, the interaction of RidL with retromer did not interfere with retromer dimerization but was essential for association of RidL with retromer-coated vacuolar and tubular endosomes. Our work thus provides structural and mechanistic evidence into how RidL is targeted to endosomal membranes.ACKNOWLEDGMENTS: We thank Ander Vidaurrazaga (Centro de Investigación Cooperativa en Biociencias) for technical assistance and Devanand Bondage (National Institute of Child Health and Human Development) for proliferation assays of Legionella pneumophila. This study made use of the Diamond Light Source (Oxfordshire, United Kingdom), the European Synchrotron Radiation Facility (Grenoble, France), and the ALBA synchrotron beamline BL13-XALOC, funded in part by the Horizon 2020 programme of the European Union, iNEXT (H2020 Grant 653706). We thank all the staff from these facilities for technical and human support. This work was supported by the Spanish Ministry of Economy and Competitiveness Grant BFU2014-59759-R (to A.H.); the Severo Ochoa Excellence Accreditation SEV-2016-0644; and the Intramural Program of the Eunice Kennedy Shriver National Institute of Child Health and Human development (Projects ZIA HD001607 and ZIA HD008893). M.R.-M. is supported by a pre-doctoral fellowship from the Basque Government (PRE_2016_2_0249)

    Combination of Pneumococcal Surface Protein A (PspA) with Whole Cell Pertussis Vaccine Increases Protection Against Pneumococcal Challenge in Mice

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    Streptococcus pneumoniae is the leading cause of respiratory acute infections around the world. In Latin America, approximately 20,000 children under 5 years of age die of pneumococcal diseases annually. Pneumococcal surface protein A (PspA) is among the best-characterized pneumococcal antigens that confer protection in animal models of pneumococcal infections and, as such, is a good alternative for the currently available conjugated vaccines. Efficient immune responses directed to PspA in animal models have already been described. Nevertheless, few low cost adjuvants for a subunit pneumococcal vaccine have been proposed to date. Here, we have tested the adjuvant properties of the whole cell Bordetella pertussis vaccine (wP) that is currently part of the DTP (diphtheria-tetanus-pertussis) vaccine administrated to children in several countries, as an adjuvant to PspA. Nasal immunization of BALB/c mice with a combination of PspA5 and wP or wPlow – a new generation vaccine that contains low levels of B. pertussis LPS – conferred protection against a respiratory lethal challenge with S. pneumoniae. Both PspA5-wP and PspA5-wPlow vaccines induced high levels of systemic and mucosal antibodies against PspA5, with similar profile, indicating no essential requirement for B. pertussis LPS in the adjuvant properties of wP. Accordingly, nasal immunization of C3H/HeJ mice with PspA5-wP conferred protection against the pneumococcal challenge, thus ruling out a role for TLR4 responses in the adjuvant activity and the protection mechanisms triggered by the vaccines. The high levels of anti-PspA5 antibodies correlated with increased cross-reactivity against PspAs from different clades and also reflected in cross-protection. In addition, passive immunization experiments indicated that antibodies played an important role in protection in this model. Finally, subcutaneous immunization with a combination of PspA5 with DTPlow protected mice against challenge with two different pneumococcal strains, opening the possibility for the development of a combined infant vaccine composed of DTP and PspA

    Il6 gene promoter polymorphism (-174G/C) influences the association between fat mass and cardiovascular risk factors

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    During the last decades, the prevalence of obesity has increased rapidly among young people. A polymorphism in the promoter region of the IL6 gene (-174G/C), has been previously reported to be involved in obesity and metabolic syndrome development. Therefore, the aim of the study was to examine whether the IL6 -174G/C polymorphism influence the association of body fat with low-grade inflammatory markers and blood lipids and lipoproteins in Spanish adolescents. 504 Spanish adolescents participating in the AVENA study were genotyped for the -174G/C polymorphism of the IL6 gene. Anthropometric and body composition measurements were taken and blood samples were collected for plasma molecules determinations. No differences between genotypes were observed in anthropometric values, body composition measurements and plasma markers concentration. Physical activity level differ between genotypes with subjects carrying the C allele of the polymorphism being significantly (p<0.05) more active than GG subjects. The association between body fat mass and plasma glucose was influenced by the -174G/C polymorphism of the IL6 gene. Subjects carrying the C allele of the mutation seem to have higher values of lipoprotein (a) and C-reactive protein as their percentage of body fat mass increase. Our results suggest that this promoter polymorphism influences the association between adiposity and some plasma markers

    Breaking through an epigenetic wall: Re-activation ofOct4by KRAB-containing designer zinc finger transcription factors

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    The gene Oct4 encodes a transcription factor critical for the maintenance of pluripotency and self-renewal in embryonic stem cells. In addition, improper re-activation of Oct4 contributes to oncogenic processes. Herein, we describe a novel designer zinc finger protein (ZFP) capable of upregulating the endogenous Oct4 promoter in a panel of breast and ovarian cell lines carrying a silenced gene. In some ovarian tumor lines, the ZFP triggered a strong reactivation of Oct4, with levels of expression comparable with exogenous Oct4 cDNA delivery. Surprisingly, the reactivation of Oct4 required a KRAB domain for effective upregulation of the endogenous gene. While KRAB-containing ZFPs are traditionally described as transcriptional repressors, our results suggest that these proteins could, in certain genomic contexts, function as potent activators and, thus, outline an emerging novel function of KRAB-ZFPs. In addition, we document a novel ZFP that could be used for the epigenetic reprograming of cancer cells
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