4,150 research outputs found

    Testimonios de un siglo de migraciones a Brasil

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    El poblamiento calcolítico en la vega del Harnina (Badajoz): documentación y discusión del modelo sociopolítico y económico

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    Este artículo da a conocer un estudio sobre el poblamiento calcolítico de la vega del arroyo Harnina, en la comarca de Tierra de Barros, realizado desde los planteamientos de la Arqueología del Territorio. La abundancia de restos, la desatención de la investigación y el serio peligro que corrían los yacimientos, nos llevaron a acometer una prospección sistemática que se ha concretado en una carta arqueológica. Del estudio de los yacimientos y de su inserción en las dinámicas culturales del Guadiana Medio se derivan unas conclusiones que sin duda enriquecerán el debate sobre la visión de un tiempo particularmente complejo, un verdadero reto para la investigación.This article shows a investigation about the Chalcolithic in the Basin of the stream Harnina, in Tierra de Barros. It was made with a methodology according to the Territorial Archaeology. The abundance of remains, the inattention from other investigators, and the danger to the ancient settlements, led us to develope a sistematic archaeologic search to create a catalogue. Our conclusions about the Chalcolitic of Harnina and its integration in the middle basin of the river Guadiana will increase the knowledge about this complex period, a challenge for archaeologists.peerReviewe

    Diseño de un manual de proveedores en la empresa Lumamexglo S.A. de C.V. de la ciudad de Chihuahua, México.

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    La presente investigación muestra la aplicación de procedimientos, requerimientos y estándares estipulados para realizar Selección y Evaluación de Proveedores acorde a las necesidades y los objetivos propuestos en la empresa LUMAMEXGLO S.A de C.V de Chihuahua, México. La investigación se basó en un diagnóstico previo el cual indicaba que la empresa no contaba con herramientas establecidas o estructuradas para una correcta y minuciosa selección de proveedores, esto necesario para obtener resultados positivos y prósperos para la empresa. De esta manera se implementó procedimientos, estándares y documentación pertinente que permitiera identificar el proveedor idóneo para la empresa, mediante la búsqueda, selección, documentación y posterior evaluación de proveedores, buscando así que estos representen los objetivos y metas a alcanzar, contribuyendo al crecimiento interno de la empresa y del mismo proveedor afianzando relaciones y así contribuyendo a mejoras continuas

    The CRYO-EM structure of RNA polymerase I stalled at UV light-induced damage unravels a new molecular mechanism to identify lesions on ribosomal DNA

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 25-10-2019In eukaryotic cells, three RNA polymerases transcribe the genome, each specialized in transcribing a specific set of genes. Pol II synthesizes mRNA, Pol III produces short untranslated RNAs and Pol I transcribes ribosomal DNA (rDNA). The latter produces the rRNA precursor, which after maturation constitutes the backbone of the ribosome. Pol I accounts for approximately 60% of the total transcriptional activity in growing cells and also carries out the supervision of rDNA integrity. Therefore, it is a key determinant for the control of the normal function of the cell. Environmental threats can generate DNA lesions that are cytotoxic for the cell and one of the most known is UV-light. The principal DNA damage produced by this external agent is cis-syn cyclobutane pyrimidine dimers (CPDs), a bulky DNA lesion that can introduce distortions in the DNA helix, thus obstructing fundamental processes such as transcription. The main goal of this Ph.D. Thesis is understanding the structural basis of Pol I stalled at UV light-induced DNA damage. The principal contribution is the cryo-EM structure at 3.6 Å resolution and the derived atomic model of Pol I in elongation complex containing a CPD lesion at the DNA TS. This structure shows that the CPD lesion induces an early translocation intermediate, along with several conformational rearrangements in Pol I structural elements inside the DNA binding cleft, which contribute to enzyme stalling. The structure revealed that the BH residue R1015 plays a relevant role for enzyme arresting, which was confirmed by mutational analysis using E.coli RNA polymerase as a model system. In vitro transcription assays comparing the Pol I and Pol II behavior in the presence of CPD reveal that, while Pol II can slowly bypass the lesion, Pol I stalls right before the lesion due to the balance between a slow nucleotide incorporation and a fast-intrinsic RNA cleavage activity. Altogether, our results reveal the molecular mechanism of Pol I stalling at CPD lesions, which is distinct from Pol II arrest. This PhD Thesis opens the avenue to unravel the molecular mechanisms underlying cell endurance to lesions on rDNATesis realizada gracias a la ayuda BES-2014-070708 del Ministerio de Ciencia, Innovación y Universidade

    Strategies for implementation of smart boards in schools of Bogota

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    Con el paso de los años, la sociedad ha venido evolucionado en el ámbito tecnológico facilitando la vida de la comunidad, y el ámbito escolar no es la excepción, donde se ve como progresivamente, se ha estado implementando las pizarras interactivas. En la actualidad, específicamente en Bogotá existen muy pocos colegios que utilicen las pizarras interactivas en sus aulas de clase como ayuda metodológica, es por esto que se presenta los múltiples beneficios que posee la utilización de esta herramienta, tales como la habilidad para el desarrollo de temas complejos, el acercamiento entre el estudiante y el profesor, la facilidad de aprendizaje mediante el uso de la pizarra en aquellos estudiantes con problemas físicos, entre otros. Así mismo, el docente encuentra múltiples herramientas para crear sus propios contenidos interactivos y que las clases resulten amenas y motiven la participación y comprensión del estudiante.Over the years, society has been evolution in the technological field making life of communities more convenient, and the educational field is not the exception, in which we can see the continuous implementation of interactive boards. Nowadays, specifically in Bogota are just a few schools that use Smart boards in their classrooms as a methodology tool. This is why we are presenting the several benefits that the use of this tool has such as the ability to develop complex topics in class, the relations between students and teachers, the help in getting knowledge using smarts boards by students with physical decease, and so on. In addition, teachers could find multiples tolos to créate their classroom interactive contentes in order to make their clases more comfortable and to encourage their student’s participation and comprehension

    The CRYO-EM structure of RNA polymerase I stalled at UV light-induced damage unravels a new molecular mechanism to identify lesions on ribosomal DNA

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 25-10-2019In eukaryotic cells, three RNA polymerases transcribe the genome, each specialized in transcribing a specific set of genes. Pol II synthesizes mRNA, Pol III produces short untranslated RNAs and Pol I transcribes ribosomal DNA (rDNA). The latter produces the rRNA precursor, which after maturation constitutes the backbone of the ribosome. Pol I accounts for approximately 60% of the total transcriptional activity in growing cells and also carries out the supervision of rDNA integrity. Therefore, it is a key determinant for the control of the normal function of the cell. Environmental threats can generate DNA lesions that are cytotoxic for the cell and one of the most known is UV-light. The principal DNA damage produced by this external agent is cis-syn cyclobutane pyrimidine dimers (CPDs), a bulky DNA lesion that can introduce distortions in the DNA helix, thus obstructing fundamental processes such as transcription. The main goal of this Ph.D. Thesis is understanding the structural basis of Pol I stalled at UV light-induced DNA damage. The principal contribution is the cryo-EM structure at 3.6 Å resolution and the derived atomic model of Pol I in elongation complex containing a CPD lesion at the DNA TS. This structure shows that the CPD lesion induces an early translocation intermediate, along with several conformational rearrangements in Pol I structural elements inside the DNA binding cleft, which contribute to enzyme stalling. The structure revealed that the BH residue R1015 plays a relevant role for enzyme arresting, which was confirmed by mutational analysis using E.coli RNA polymerase as a model system. In vitro transcription assays comparing the Pol I and Pol II behavior in the presence of CPD reveal that, while Pol II can slowly bypass the lesion, Pol I stalls right before the lesion due to the balance between a slow nucleotide incorporation and a fast-intrinsic RNA cleavage activity. Altogether, our results reveal the molecular mechanism of Pol I stalling at CPD lesions, which is distinct from Pol II arrest. This PhD Thesis opens the avenue to unravel the molecular mechanisms underlying cell endurance to lesions on rDNATesis realizada gracias a la ayuda BES-2014-070708 del Ministerio de Ciencia, Innovación y Universidade

    Publicaciones cervantinas de autoría femenina (1905-1916)

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    La aportación de la mujer al ensayo cervantino de principios del siglo XX apenas ha merecido atención. En este trabajo se analizan las diferentes perspectivas desde las que las mujeres intelectuales enfocan tanto la obra de Cervantes como a su autor, al hilo de los centenarios cervantinos (1905-1916). La crítica literaria estricta convive con la recreación de los personajes principales del Quijote en los ensayos de María Lejárraga, Matilde Ras, Concha Espina y Carmen de Burgos. Varias de las autoras estudiadas incluyen en sus textos sus preocupaciones sociales, como el feminismo, y dejan su opinión sobre los conflictos políticos y doctrinales que marcaron el fin de siglo.Women's participation in Cervantine criticism at the beginning of the twentieth century (1905-1906) has barely received recognition. This paper analyses the different perspectives women authors used to approach both Cervantes and his work. Strict literary criticism coexists with the exploration of Don Quixote's main characters in the philosophical and literary essays of María Lejárraga, Matilde Ras, Concha Espina and Carmen de Burgos. The authors studied include intheirs texts their social concerns and feminist ideology and give their opinion about key political and intellectual debates affecting society at the beginning of the twentieth century
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