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Search Results: 1 - 10 of 282618 matches for " Juan Carlos Raya Pérez "
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Las Bases Moleculares del Cáncer Las Bases Moleculares del Cáncer
Juan Carlos Raya Pérez
Acta Universitaria , 2012,
Abstract: El estudio del cáncer a nivel molecular ha permitido el descubrimiento de gran cantidad de genes mutados relacionados con esta enfermedad. Estos genes son supresores de tumores u oncogenes, que tienen con ver la proliferación celular, la metástasis y/o la capacidad de las células para inducir la vascularización del tejido. La búsqueda de terapias ha llevado al descubrimiento de muchas moléculas capaces de inhibir el crecimiento de las células cancerosas, aunque la mejor opción sigue siendo la revisión periódica y la prevención. Al parecer, pese a los avances, los marcadores moleculares fallan en un alto porcentaje al tratar de diagnosticar un cáncer, así como al tratar de dar un pronóstico. Esto podría deberse al hecho de que se esta abordando el problema a nivel de célula. Cancer research has allowed us to discover many genes implied in development of this disease. These genes are suppressors or oncogenes that participate in cellular proliferation, methastasis and/or capacity of cell to induce vascularization of the tissue. Also, it has allowed the discovery of molecules able to inhibit the growth of cells cancerous. However, periodic checkups continues to be the best prevention against cancer. At molecular level is difficult to diagnose it, perhaps because is necessary to go to the tissue level. Molecular markers are not yet a reliable method in order to obtain a diagnosis or forecast cancer, maybe because one forgets the tissue level.
La Estructura de la Cromatina y la Regulación de la Transcripción La Estructura de la Cromatina y la Regulación de la Transcripción
Juan Carlos Raya Pérez
Acta Universitaria , 2012,
Abstract: Transcription in eucaryotes is aprocess investigated with great interest because is one of the crucial steps to understand how the DNA information is transformed in a complex organism. In this paper some of the most important steps in the genetic transcription control are revised giving some illustrative examples. La transcripción en eucariotas son eventos a los que se les investiga con gran interés, pues es uno de los pasos cruciales para tratar de entender cómo la información del DNA es transformada en un organismo complejo. Aquí se revisan algunos de los pasos más importantes del control de la transcripción genética, haciendo énfasis en la estructura de la cromatina. Se dan algunos ejemplos ilustrativos.
El Fototropismo en Plantas El Fototropismo en Plantas
Juan Carlos Raya Pérez
Acta Universitaria , 2012,
Abstract: El estudio del fototropismo ha llevado al aislamiento del gen que codifica para la fototropina. También se ha logrado el aislamiento de otros genes relacionados, como nph4, nph3 y rpt2. Es de esperarse que en los próximos a os se establezca la vía de se alización en que participan las fototropinas, vías poco dilucidadas hasta ahora. Studies on the molecular basis of phototropism have led to the isolation of the phototropin gene. Others genes involved in the phototropic response such as nph4, nph3 and rpt2 have also been isolated. It isexpected that in the near future it will be established what is the participation of the phototropins, unknown until know, by means of signalling.
De los Genomas, los Animales, los Humanos y la Etología De los Genomas, los Animales, los Humanos y la Etología
Juan Carlos Raya Pérez
Acta Universitaria , 2012,
Abstract: La secuenciación de los genomas abre la posibilidad de la búsqueda de genes relacionados con enfermedades y con alteraciones de la conducta. Será interesante averiguar, con la herramienta de la genómica y de la proteómica, cómo se heredan las pautas de conducta. Las secuencias de los genes y la estructura y función de las proteínas nos confirman que compartimos las mismas moléculas con casi todos los organismos vivos. Esto cambiará la visión que tengamos acerca de nosotros mismos y de las otras criaturas, lo que debe motivar una reflexión acerca de la relación entre la bioética y la ciencia. Genomic sequentiation opens the possibility for searching genes related to diseases and behavior alterations. It should be interesting, using the genomic and proteomic tools, to investigate how patterns of behavior are inherited. Gene sequences and the structure and functions of the proteins confirm that we share the same molecules with the rest of the living organisms. These facts will change the vision that we have about us and other living creatures and should motivate to reflect about the relationship between bioethics and science.
Calidad física y fisiológica de semilla en función de la densidad de población en dos híbridos de maíz Physical and physiological seed quality in function of the density of population in two maize hybrids
Juan Carlos Raya Pérez,César Leobardo Aguirre Mancilla,J. Guadalupe Medina Ortíz,Juan Gabriel Ramírez Pimentel
Revista mexicana de ciencias agrícolas , 2012,
Abstract: La densidad de población afecta algunos caracteres agronómicos en las variedades, como la calidad física y fisiológica de la semilla. Con el objetivo de evaluar este efecto, se sembraron dos genotipos hembra de dos híbridos comerciales de maíz (Zea mays L.); las densidades evaluadas fueron 52 630, 65 789, 78 789, 92 013 y 105 263 plantas ha-1 en el campo experimental del Instituto Tecnológico de Roque, Guanajuato. Se eligió un experimento factorial con dise o de bloques completos al azar con cuatro repeticiones. Se evaluó altura de planta, de mazorca, días a floración femenina, hojas fotosintéticamente activas, amacollamiento, ataque de Fusarium spp., acame de tallo, plantas ''horras'' y rendimiento de grano; la calidad de la semilla fue evaluada mediante peso volumétrico, análisis de pureza, peso de 1 000 semillas y clases de semilla. La calidad fisiológica, a través de la germinación estándar y el vigor. Los resultados obtenidos muestran que la densidad de población tuvo efectos estadísticamente significativos en las siguientes variables agronómicas: altura de planta y de mazorca, número de hojas fotosintéticamente activas, amacollamiento, porcentaje de plantas ''horras'' y rendimiento de grano; así, al menos una densidad es superior o permite observar diferencias entre ellas; en ninguna variable de este grupo se presentó efectos de interacción entre genotipos y densidades, indicando independencia entre estos factores. Population density affects some agronomic traits in varieties such as physical and physiological quality of the seed. In order to assess this effect, two female genotypes were grown of two commercial hybrids of maize (Zea mays L.); the evaluated densities were 52 630,65 789,78 789,92 013 and 105 263 plants ha-1 in the experimental field of Roque Institute of Technology, Guanajuato. A factorial experiment was chosen, using arandomized complete block design with four replications. We evaluated plant height, ear size, days to silking, photosynthetically active leaves, tillering, attack of Fusarium spp., stalk lodging, plant ''horras'' and grain yield; seed quality was evaluated by volumetric weight, purity analysis, weight of 1000 seeds and seed classes. The physiological quality, through the standard germination and vigor. The results show that, the density of population had statistically significant effects on the following agronomic traits: plant height and ear size, photosynthetically active leaf number, tillering, percentage of plants ''horras'' and grain yield; so, at least one density is higher or allow to see differences between th
El museo, la museología y la fuente de información museística
Linarez Pérez,Juan Carlos;
ACIMED , 2008,
Abstract: the training of information professionals requires an integrative vision that assesses the meaning and importance museums have had and still have. the history of the museums has evolved just as the history of humanity; the origin of the term mouseion, dates back to the worship to the muses in the old greek regions of tracia and beocia. in america, as opposed to europe, the museums consolidated the nationalist and historic feelings. museology is the field of knowledge that confers formality and scientific rigorousness to the museum activity. starting from the dimensions of analysis proposed by van mensch (1995), the most significant elements of museum knowledge can be established; nevertheless, these dimensions cannot be seen as an abstract atomization of the knowledge in museology; they are, on the contrary, complementary verifiable elements. while the theoretical-empirical approach is of an especially heuristic character, that of the functional rationality aims to the design of behavior strategies, whereas the critic-philosophical approach seeks to develop a definitive point of view of paradigmatic connotations.
Juicios y cambios políticos: una visión epistémica
Pérez Toribio,Juan Carlos;
Argos , 2009,
Abstract: as a result of the profound political upheavals that have been and continue to be witnessed in some latin american countries over the last few years, we attempt to show the difficulties involved in describing social events in such circumstances, giving rise to what we might call a conflict of interpretations. in this sense, we explore the epistemological and epistemic possibilities that should be taken into account to allow us to consider certain judgments as true or otherwise. we also stress the importance of values and language in terms of what are finally considered as "facts" after weighing up both the rationality and reasonableness that judgments should be provided with.
El museo, la museología y la fuente de información museística Museums, museology and the sources of museum information
Juan Carlos Linarez Pérez
ACIMED , 2008,
Abstract: La formación de profesionales de la información requiere de una visión integradora que valore la significación e importancia que han tenido y aún conservan los museos. La historia de los museos ha transcurrido en forma paralela con la historia de la humanidad. El origen del término mouseion, se remonta al culto que se rendía a las musas en las antiguas regiones griegas de Tracia y Beocia. En América, a diferencia de Europa, los museos sirvieron para el afianzamiento de los sentimientos históricos y nacionalistas. La museología se erige como campo del conocimiento que confiere formalidad y rigurosidad científica a la actividad museística. Partiendo de las dimensiones de análisis que propone van Mensch (1995), pueden establecerse los elementos más significativos del conocimiento museológico; sin embargo, estas dimensiones no pueden verse como una atomización abstracta del conocimiento en la museología; son, por el contrario, elementos que se complementan, verificables. En tanto la aproximación teórico-empírica es de carácter eminentemente heurístico, la de la racionalidad funcional apunta hacia el dise o de estrategias de comportamiento y la crítico-filosófica busca el desarrollo de un punto de vista definitivo de connotaciones paradigmáticas. The training of information professionals requires an integrative vision that assesses the meaning and importance museums have had and still have. The history of the museums has evolved just as the history of humanity; the origin of the term mouseion, dates back to the worship to the muses in the old Greek regions of Tracia and Beocia. In America, as opposed to Europe, the museums consolidated the nationalist and historic feelings. Museology is the field of knowledge that confers formality and scientific rigorousness to the museum activity. Starting from the dimensions of analysis proposed by van Mensch (1995), the most significant elements of museum knowledge can be established; nevertheless, these dimensions cannot be seen as an abstract atomization of the knowledge in Museology; they are, on the contrary, complementary verifiable elements. While the theoretical-empirical approach is of an especially heuristic character, that of the functional rationality aims to the design of behavior strategies, whereas the critic-philosophical approach seeks to develop a definitive point of view of paradigmatic connotations.
Real Hypersurfaces in Complex Two-Plane Grassmannians Whose Jacobi Operators Corresponding to -Directions are of Codazzi Type  [PDF]
Carlos J. G. Machado, Juan de Dios Pérez, Young Jin Suh
Advances in Pure Mathematics (APM) , 2011, DOI: 10.4236/apm.2011.13015
Abstract: We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators or the Jacobi corresponding to the directions in the distribution are of Codazzi type if they satisfy a further condition. We obtain that that they must be either of type (A) or of type (B) (see [2]), but no one of these satisfies our condition. As a consequence, we obtain the non-existence of Hopf real hypersurfaces in such ambient spaces whose Jacobi operators corresponding to -directions are parallel with the same further condition.
INFLUENCIA DE LAS TARJETAS DE DEBITO SOBRE LA DEMANDA DE EFECTIVO
Pérez Velasco Pavón,Juan Carlos;
Cuadernos de economía , 2002, DOI: 10.4067/S0717-68212002011600003
Abstract: within by the electronic money definition, the plastics have a significant place, both the debit cards and the new option, even in the experimental stage known as the electronic purse or prepayment. the advanced technological changes, especially the incorporated microchips into plastics and the internet have facilitated the payment system. these circumstances (the facilities with plastics) have generated the acceptation on the debit card and the electronic purse by the people, and it has altered and transformed several habits deeply rooted in our customs, in particular in latin america. the goal of this work is to develop a demand model of bills and coins model, such as the baumol-tobin inventory model. it includes the option of the buyers to buy their items with cash or debit cards. the sellers cash demand is added to the model because it is a necessary condition in order to find the solution. the sellers could accept debit card only if they have a machine capable of making the necessary transactions between the bank account's client and bank account's seller. if they don't have a machine, they will only accept cash. if we incorporate the sellers cash demand, we will be able to find the proportion of debit card expenditure. this share depends on the quantity of sellers with debit card machine. the benefit of this model is that we can study the debit cards as substitution of cash
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