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Search Results: 1 - 10 of 334354 matches for " Patricia Padilla Cortés "
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Selective and constructive mechanisms contribute to neural circuit formation in the barrel cortex of the developing rat  [PDF]
Eileen Uribe-Querol, Eduardo Martínez-Martínez, Luis Rodrigo Hernández, Patricia Padilla Cortés, Horacio Merchant-Larios, Gabriel Gutiérrez-Ospinac
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.47103
Abstract: The cellular strategy leading to formation of neuronal circuits in the rodent barrel cortex is still a matter of controversy. Both selective and constructive mechanisms have been proposed. The selective mechanism involves an overproduction of neuronal processes and synapses followed by activity dependent pruning. Conversely, a constructive mechanism would increase the number of axons, dendrites, and synapses during development to match functionality. In order to discern the contributions of these two mechanisms in establishing a neuronal circuit in the somatosensory cortex, morphometric analysis of dendritic and axonal arbor growth was performed. Also, the number of synapses was followed by electron microscopy during the first month of life. We observed that axonal and dendritic arbors retracted distal branches, and elongated proximal branches, resulting in increased arbor complexity. This neuronal remodeling was accompanied by the steady increase in the number of synapses within barrel hollows. Similarly, the content of molecular markers for dendrites, axons and synapses also increased during this period. Finally, cytochrome oxidase activity rose with age in barrels indicating that the arbors became more complex while synapse density and metabolic demands increased. Our results support the simultaneous use of both selective and constructive mechanisms in establishing the barrel cortex circuitry.

Las elites y la institucionalización de los partidos políticos
Ricardo Cortés Padilla
Espacios Públicos , 2007,
Abstract: En este ensayo de investigación se estudia el análisis del marco teórico sobre las elites políticas, se hace alusión a los aportes de los principales autores más representativos en la materia; además, se analiza la estructura interna de los partidos políticos, que determina su grado de institucionalización, en específico el relativo a la conformación y renovaci ón de sus elites partidistas.
La agudización de las contradicciones del presidencialismo mexicano
Ricardo Cortés Padilla
Espacios Públicos , 2008,
Abstract: Este artículo presenta un análisis de la pertinencia del presidencialismo en México, a la luz de los fundamentos teóricos en los que descansan los regímenes de gobierno presidencial parlamentario y semipresidencial, de cara a los nuevos retos de pluralidad democrática que enfrenta nuestro país hoy en día.
Sensory neurons in the spinal cord of nominal female embryos in the marine turtle Lepidochelys olivacea respond to shifts in incubation temperature: implications for temperature dependent sex determination  [PDF]
Francisco Jiménez-Trejo, Leonora Olivos-Cisneros, Julieta Mendoza-Torreblanca, Sofía Díaz-Cintra, Esperanza Meléndez-Herrera, Armida Báez-Salda?a, Patricia Padilla Cortés, Gabriel Gutiérrez-Ospina, Alma Lilia Fuentes-Farías
Advances in Bioscience and Biotechnology (ABB) , 2011, DOI: 10.4236/abb.2011.21001
Abstract: Gonadal determination in marine turtles depends on incubation temperature. The mechanisms that spark off this process remain unclear. Previously, we proposed that sensory nerves reaching the gonadal primordium in nominal female embryos of Lepidochelys (L) olivacea may sense and signal incubation temperature. These nerves could later trigger ovarian determination by releasing neurotransmitters in a code constructed based on the thermal information (Gutierrez-Ospina et al., Acetylcholinesterase-positive innervation is present at the undifferentiated stages of the sea turtle Lepidochelys olivacea embryo gonads: implications for temperature-dependent sex determination, J. Comp. Neurol. 410 (1999) 90-98). The hypothesis briefly described, however, has been recently refuted under weak theoretical grounds and experimental misinterpretations (see introduction). Here, we present preliminary results that show that nominal female embryos have sensory neurons located in the dorsal horn laminae I and II of the lumbar spinal cord that display increased c-Fos-like immuno-staining after being incubated either at 15°C or 50°C. Because these spinal neurons are the primary central target of dorsal root ganglion neurons that innervate the urogential crest, these observations keep open the possibility that gonadal sensory nerves indeed signal thermal information that could later be used to trigger or instruct ovarian specification in marine turtles.
Análisis de las patologías con mayor prevalencia en las Unidades Móviles de Rehabilitación y Fisioterapia de la provincia de Almería
López-Liria,Remedios; Padilla-Gógora,David; Catalán-Matamoros,Daniel J.; Rocamora-Pérez,Patricia; Martínez-Cortés,M.a del Carmen; Rodríguez-Martín,César R.;
Gaceta Sanitaria , 2012, DOI: 10.1016/j.gaceta.2011.09.017
Abstract: objectives: to describe the most prevalent disorders in 1753 patients referred to home rehabilitation and home physiotherapy units. method: we carried out a cross-sectional descriptive study. the variables analyzed were age, gender, main diagnosis, functional capacity (barthel index), physiotherapeutic objectives, the treatment applied and the number of sessions. results: the main diagnoses were immobilization effects (29%), hip fracture (16.5%), stroke (13.7%), knee replacement (11.9%), hip replacement (4.7%), chronic obstructive pulmonary disease (2.6%), and alzheimer's disease (2.4%). the lowest barthel index was obtained in alzheimer's disease, stroke and immobilization effects and the highest in patients with knee replacement. the process requiring the highest number of sessions for complete recovery was stroke. conclusions: significant improvements were confirmed in pre- and post- barthel index scores for each of the above-mentioned diagnoses, demonstrating greater functional independence among patients.
Differential Expression of Serotonin, Tryptophan Hydroxylase and Monoamine Oxidase A in the Mammary Gland of the Myotis velifer Bat
Cristián Vela Hinojosa, Miguel Angel León Galván, Miguel Tapia Rodríguez, Gerardo López Ortega, Marco Antonio Cerbón Cervantes, Carmen Adriana Mendoza Rodríguez, Patricia Padilla Cortés, Luis Antonio Martínez Méndez, Francisco Javier Jiménez Trejo
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0075062
Abstract: The mammary gland has long drawn the attention of the scientific community due to the limited knowledge of some fundamental aspects involved in the control of its function. Myotis velifer, a microchiropteran species, provides an interesting model to study some of the regulatory factors involved in the control of the mammary gland cycle. Having an asynchronous, monoestrous reproductive pattern, female M. velifer bats undergo drastic morphological changes of the breast during the reproductive cycle. Current research on non-chiropteran mammals indicates that serotonin (5-HT) plays a major role in the intraluminal volume homeostasis of the mammary gland during lactation; however, an analysis of both the expression and localization of the main components of the serotonergic system in the bat mammary gland is lacking. Thus, the objectives of the present study were: to describe the gross and histological anatomy of the mammary gland of M. velifer to establish the lactation period for this species; to analyze the distribution and expression of the main serotonergic components in the mammary tissues of these bats under the physiological conditions of lactation, involution and the resting phase; and to provide information on the involvement of 5-HT in the regulation of the physiological function of this organ. To assess the expression and localization of serotonergic components, multiple immunofluorescence, Western blot and HPLC methods were used. 5-HT and the enzyme that catalyzes its synthesis (TPH) were located in both myoepithelial and luminal epithelial cells, while the enzyme responsible for the catabolism of this neurohormone (MAO A) was found in luminal epithelial cells as well as in secreted products. We also found an increased expression of serotonergic components during lactation, indicating that elements of the serotonergic system may play an important role in lactation in this species of bat in a way similar to that of other mammal species.
Shifts in Developmental Timing, and Not Increased Levels of Experience-Dependent Neuronal Activity, Promote Barrel Expansion in the Primary Somatosensory Cortex of Rats Enucleated at Birth
Ingrid Fetter-Pruneda, Helga Geovannini-Acu?a, Cecilia Santiago, Ana Sofía Ibarrarán-Viniegra, Eduardo Martínez-Martínez, Marcela Sandoval-Velasco, Laura Uribe-Figueroa, Patricia Padilla-Cortés, Gabriela Mercado-Célis, Gabriel Gutiérrez-Ospina
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054940
Abstract: Birth-enucleated rodents display enlarged representations of whiskers (i.e., barrels of the posteromedial subfield) in the primary somatosensory cortex. Although the historical view maintains that barrel expansion is due to incremental increases in neuronal activity along the trigeminal pathway during postnatal development, recent evidence obtained in experimental models of intramodal plasticity challenges this view. Here, we re-evaluate the role of experience-dependent neuronal activity on barrel expansion in birth-enucleated rats by combining various anatomical methods and sensory deprivation paradigms. We show that barrels in birth-enucleated rats were already enlarged by the end of the first week of life and had levels of metabolic activity comparable to those in control rats at different ages. Dewhiskering after the postnatal period of barrel formation did not prevent barrel expansion in adult, birth-enucleated rats. Further, dark rearing and enucleation after barrel formation did not lead to expanded barrels in adult brains. Because incremental increases of somatosensory experience did not promote barrel expansion in birth-enucleated rats, we explored whether shifts of the developmental timing could better explain barrel expansion during the first week of life. Accordingly, birth-enucleated rats show earlier formation of barrels, accelerated growth of somatosensory thalamocortical afferents, and an earlier H4 deacetylation. Interestingly, when H4 deacetylation was prevented with a histone deacetylases inhibitor (valproic acid), barrel specification timing returned to normal and barrel expansion did not occur. Thus, we provide evidence supporting that shifts in developmental timing modulated through epigenetic mechanisms, and not increased levels of experience dependent neuronal activity, promote barrel expansion in the primary somatosensory cortex of rats enucleated at birth.
Takeuchi Tam,Caori Patricia; Cortés Cortés,Juan Carlos;
Revista Facultad Nacional de Agronomía, Medellín , 2011,
Abstract: in this paper, the process of cutting the bamboo guadua, the production of slats, the manufacture of laminates and results of tests in slats and laminated samples made with four types of glue: -melamine, resorcinol, polyvinyl acetate and natural glue are presented. it was found that the longitudinal shrinkage of the bamboo guadua slats is relatively low and the relationship between the tangential and radial shrinkage was close to one showing the feasibility of using bamboo for laminated processes. the following average values of resistance were found: for parallel shear 47 kg?cm-2 (melamine), 51 kg?cm-2 (resorcinol), 17 kg?cm-2 (pva) and 32 mpa kg?cm-2 (kola); for perpendicular shear 50 kg?cm-2 (melamine), 43 kg?cm-2 (resorcinol), 49 kg?cm-2 (pva) and 37 kg?cm-2 (kola); for perpendicular tension 8,3 kg?cm-2 (melamine), 4,9 kg?cm-2 (resorcinol), 1,7 kg?cm-2 (pva) and 3,7 mpa kg?cm-2 (kola); for parallel compression 419 kg?cm-2 (melamine), 424 kg?cm-2 (resorcinol), 506 kg?cm-2 (pva) and 375 kg?cm-2 (kola) and for perpendicular compression 216 kg?cm-2 (melamine), 206 kg?cm-2 (resorcinol), 245 kg?cm-2 (pva) and 240 kg?cm-2 (kola). in general, the specimens made with melamine and resorcinol showed a better mechanical performance.
Caori Patricia Takeuchi Tam,Juan Carlos Cortés Cortés
Revista Facultad Nacional de Agronomía, Medellín , 2011,
Abstract: Se presentan los procesos de corte del bambú guadua, la obtención de láminas, la fabricación de laminados y los resultados de ensayos en láminas y probetas laminadas elaboradas con cuatro tipos de pegantes: melamina, resorcinol, acetato de polivinilo y cola natural. Se encontró que la retracción longitudinal de las láminas es relativamente baja y la relación entre las retracciones tangencial y radial fue cercana a 1,0 mostrando la viabilidad del uso del bambú guadua para procesos de laminado. Se encontraron los siguientes valores de resistencia promedio: a corte paralelo 47 kg cm-2 (melamina), 51 kg cm-2 (resorcinol), 17 kg cm-2 (PVA) y 32 kg cm-2 MPa (cola); a corte perpendicular 50 kg cm-2 (melamina), 43 kg cm-2 (resorcinol), 49 kg cm-2 (PVA) y 37 kg cm-2 (cola); a tracción perpendicular 8,3 kg cm-2 (melamina), 4,9 kg cm-2 (resorcinol), 1,7 kg cm-2 (PVA) y 3,7 kg cm-2 MPa (cola); a compresión paralela 419 kg cm-2 (melamina), 424 kg cm-2 (resorcinol), 506 kg cm-2 (PVA) y 375 kg cm-2 (cola) y a compresión perpendicular 216 kg cm-2 (melamina), 206 kg cm-2 (resorcinol), 245 kg cm-2 (PVA) y 240 kg cm-2 (cola). Se observó que en general las probetas elaboradas con melamina y resorcinol presentaron un mejor comportamiento mecánico. In this paper, the process of cutting the bamboo guadua, the production of slats, the manufacture of laminates and results of tests in slats and laminated samples made with four types of glue: -melamine, resorcinol, polyvinyl acetate and natural glue are presented. It was found that the longitudinal shrinkage of the bamboo guadua slats is relatively low and the relationship between the tangential and radial shrinkage was close to one showing the feasibility of using bamboo for laminated processes. The following average values of resistance were found: for parallel shear 47 kg cm-2 (melamine), 51 kg cm-2 (resorcinol), 17 kg cm-2 (PVA) and 32 MPa kg cm-2 (kola); for perpendicular shear 50 kg cm-2 (melamine), 43 kg cm-2 (resorcinol), 49 kg cm-2 (PVA) and 37 kg cm-2 (kola); for perpendicular tension 8,3 kg cm-2 (melamine), 4,9 kg cm-2 (resorcinol), 1,7 kg cm-2 (PVA) and 3,7 MPa kg cm-2 (kola); for parallel compression 419 kg cm-2 (melamine), 424 kg cm-2 (resorcinol), 506 kg cm-2 (PVA) and 375 kg cm-2 (kola) and for perpendicular compression 216 kg cm-2 (melamine), 206 kg cm-2 (resorcinol), 245 kg cm-2 (PVA) and 240 kg cm-2 (kola). In general, the specimens made with melamine and resorcinol showed a better mechanical performance.
Motivación y rendimiento en una carrera del área de química de la Universidad Católica del Norte - Chile
Pedro Ramírez,Patricia Cortés
Psicoperspectivas : Individuo y Sociedad , 2008,
Abstract: Este artículo corresponde a un extracto de uno de los informes técnicos (Ramírez, Cortés, 2002c) desarrollados el a o 2002 dentro del contexto de continuidad del Proyecto “Estilo Cognoscitivo y Permanencia en una Carrera Universitaria: la perspectiva de un análisis multivariado para las Universidades de la Segunda Región”, explora y describe el efecto que tiene la motivación por la carrera sobre el rendimiento académico de un alumno de primer a o y su permanencia en la carrera en que se ha matriculado. El proyecto mencionado tiene como objetivo describir el efecto de la motivación por la carrera a la que han ingresado, vía PAA, los alumnos de la cohorte de admisión de cada una de las carreras observadas, con el propósito de producir información que puedan utilizar tanto jefes de carrera, profesores tutores y otros profesionales que se relacionan con los alumnos de manera formal, como los niveles superiores de las entidades universitarias responsables de la determinación de políticas de selección, admisión y desarrollo académico de los estudiantes que ingresan a una Universidad. (Ramírez,Yany, 1993). Bajo un dise o de investigación no experimental, transeccional, descriptivo, los investigadores presentan el resultado de una de las nueve observaciones de motivación, bajo la concepción teórica de Vroom, realizadas el primer semestre académico del a o 2002, describiendo la motivación de los estudiantes de primer a o, cohorte 2002, hacia la carrera “Plan Común de Química” de la Facultad de Ciencias de la U. Católica del Norte, Sede Antofagasta, a partir de los datos motivacionales y sociodemográficos que se recogen durante la aplicación del “Inventario V.E.I. 02”. La información que proporciona el inventario permite reconocer, inmediatamente, el potencial de autoselección como estudiantes de “bajo rendimiento” que posee la población bajo estudio y predecir, a partir de un análisis de regresión lineal múltiple, su eventual rendimiento académico en el curso inmediato de sus estudios universitarios. La motivación, para los alumnos de primer a o del Plan Común de Química, ingreso 2002, fue 0,29, dentro de un rango que va desde –1 hasta 1. Mientras, la ecuación de regresión lineal para la variable dependiente, Rendimiento académico (RA) y las 10 variables independientes que consideró el modelo, es: RA = 0,000824043 * NEM + 0,00432805 * PAA + 0,0610368 * OPP – 0,00172809 * AE + 0,0189326 * RO + 0,264077 * OP + 0,384012 * VA + 0,689646 * IN – 0,584943 * M + 0,269981 * CC
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