903 research outputs found
Efecto de la activación adrenérgica insular en la neofobia gustatoria
Tesis (Magíster en Biotecnología)Este proyecto ha sido financiado por el Proyecto Fondecyt nº 1130724.La respuesta frente al estrés corresponde a la capacidad de un organismo de
responder frente a un estímulo estresante y volver a su homeostasis. Esta respuesta es
iniciada por la respuesta autonómica, mediada principalmente por actividad adrenérgica,
la cual es modulada por catecolaminas, entre las cuales se destacan la norepinefrina
(NE) a nivel de sistema nervioso central, y epinefrina (EPI) a nivel periférico.
Se conoce una serie de áreas del cerebro asociadas a la respuesta al estrés,
incluyendo la amígdala extendida, locus coeruleus, hipocampo, corteza prefrontal, entre
varias. Una de las áreas del cerebro que ha sido propuesta muy recientemente como
mediadora de la respuesta fisiológica frente al estrés es la corteza insular. Esta área
recibe información emocional, visceral y gustatoria, y aún se desconoce por qué su
actividad se ve alterada en trastornos de ansiedad. Es posible estudiar el rol de la ínsula
en ansiedad usando conductas asociadas a gustos que sean sensibles al estrés y
ansiedad, como la neofobia gustatoria. La neofobia gustatoria se describe como el
miedo a un gusto nuevo, y es exacerbada en ambientes de estrés (hiponeofagia),
siendo una medición de comportamiento tipo ansioso en animales.
Este trabajo tuvo como objetivo evaluar si la actividad adrenérgica en la corteza
insular media el aumento en neofobia gustatoria inducido por la presentación de un
gusto nuevo en un ambiente de alta exaltación. La hipótesis que sustenta este trabajo
es que la actividad adrenérgica en la corteza insular aumenta la neofobia
gustatoria y modula el incremento de neofobia inducida por un ambiente de alta
exaltación. Para probar la hipótesis se usó una combinación de microinyecciones de
NE y propranolol intra insular y de inyecciones subcutáneas de EPI y propranolol, antes
de la presentación del gusto en contextos con alta y baja exaltación. Los resultados
obtenidos apoyan la hipótesis. Nuestros resultados proponen que la actividad
adrenérgica periférica media la respuesta de neofobia gustatoria en ambientes de alta
exaltación, efecto que es modulado por actividad adrenérgica en la corteza insular.The stress response is the ability of an organism to respond to a stressor and
return to homeostasis. The first body's response to stress is the autonomic response,
primarily mediated by adrenergic activity, which is modulated by catecholamines, among
which norepinephrine is the predominant in the central nervous system, and epinephrine
peripherally. Studies show that a dysregulation in the levels of these hormones may lead
to psychiatric disorders including anxiety disorders.
Among several brain areas involved in stress response, including the extended
amygdala, locus coeruleus, hippocampus and prefrontal cortex, the insular cortex has
been recently associated with physiological responses to stress. This area receives
emotional, visceral and gustatory information, but it is still unknown why its activity is
altered in anxiety disorders. It is possible to study the role of the insula in anxiety using
behaviors associated with tastes which are sensitive to stress and anxiety, such as
gustatory neophobia. The gustatory neophobia is the reluctance or fear to try a new
taste, and is exacerbated in arousing contexts (also known as hyponeophagia), being a
widely used to measure anxiety in animals.
This study aimed to evaluate to which extent the adrenergic activity in the medial
insular cortex increases gustatory neofobia induced by arousing novel contexts. The
hypothesis behind this study is that adrenergic activity in the insular cortex increases
taste neophobia and modulates the increment in neophobia induced by an
arousing context. To test this hypothesis we used a combination of intrainsular microinjections
of norepinephrine and propranolol and peripheral injections of epinephrine and
propranolol before presentation of a novel taste in contexts of high and low arousal. Our
results support the hypothesis and suggest that peripheral adrenergic activity mediates
arousal induced increases in neophobia, effect that is mediated by adrenergifc activity in
the insular cortex
An energy-efficient distributed dynamic bandwidth allocation algorithm for Passive Optical Access Networks
The rapid deployment of passive optical access networks (PONs) increases the global energy consumption of networking infrastructure. This paper focuses on the minimization of energy consumption in Ethernet PONs (EPONs). We present an energy-efficient, distributed dynamic bandwidth allocation (DBA) algorithm able to power off the transmitter and receiver of an optical network unit (ONU) when there is no upstream or downstream traffic. Our main contribution is combining the advantages of a distributed DBA (namely, a smaller packet delay compared to centralized DBAs, due to less time being needed to allocate the transmission slot) with energy saving features (that come at a price of longer delays due to the longer queue waiting times when transmitters are switched off). The proposed algorithm analyzes the queue size of the ONUs in order to switch them to doze/sleep mode when there is no upstream/downstream traffic in the network, respectively. Our results show that we minimized the ONU energy consumption across a wide range of network loads while keeping delay bounded.Postprint (published version
Evaluación Intermedia de un proyecto de mediación escolar en Portugal=Avaliaçao Intermédia de um projecto de mediaçao escolar em Portugal
En este artículo se describe la investigación realizada en una escuela portuguesa. Se trató de una evaluación
complementaria al proceso de auto-evaluación existente y referente a tres dimensiones consideradas
esenciales para la toma de decisiones sobre el futuro del proyecto: pertinencia, eficacia y eficiencia.
Se utilizó una metodología mixta, con el respaldo de un paradigma ecléctico, sobre la base de un estudio
de caso simple de subtipo anidado. Fueran elegidas fuentes documentales y entrevistas en profundidad a
informantes privilegiados; la investigación se basó en la análisis documental y de contenido, estadística
descriptiva y un test no paramétrico de chi - cuadrado para testar la independencia entre la expulsión y el
fracaso escolar.___________________________________________O presente artigo descreve a investigação levada a cabo numa escola portuguesaTratou-se de uma avaliação
intermédia, complementar ao processo de auto-avaliação e referente a três dimensões consideradas
essenciais para a tomada de decisões quanto ao futuro do projecto: relevância, eficácia e eficiência.
Foi utilizada uma metodologia mista, sustentada por um paradigma eclético, assente num estudo de caso
simples de subtipo aninhado. Optou-se pelo recurso a fontes documentais e entrevistas em profundidade a
informadores privilegiados; a investigação foi efectuada com base na análise documental e de conteúdo,
estatística descritiva e um teste não paramétrico qui - quadrado para testar a independência entre expulsão
e insucesso escolar
Detección y reconocimiento de guiños basado en análisis EEG utilizando redes neuronales
This paper proposes an automatic eyewink interpretation system based on EEG signal analysis for human-machine interface to benefit people with disabilities. Our system investigates the use of the Emotiv EPOC as a relatively low cost new method for acquiring EEG signals and the implementation of Artificial Neural Networks (ANN) for the classification algorithm. The proposed algorithm has been found effective in detecting and classifying the eyewinks that then can be translated to valid command for human-machine interface. The performance of the proposed approach is investigated using two types of ANN topologies, and the results obtained indicate a high rate of classification accuracy
Influencia de la masa de los muros no estructurales en la fuerza sísmica y en el costo del edificio en concreto reforzado GAIA 104
El presente proyecto se realizó con el fin de determinar la influencia de los muros no estructurales, correspondientes a los muros divisorios y de fachada, en la fuerza sísmica y el costo de un edificio en concreto reforzado. Se tomó como base un edificio construido en la ciudad de Bogotá, con el cual se analizó bajo diferentes escenarios, la variación de materiales utilizados para conformar muros no estructurales, correspondientes a muros divisorios y de fachada. De esta manera, se podrá determinar cómo dicha variación afecta el diseño de los elementos que componen la estructura y la cimentación, en términos de cantidades de acero y concreto. Además, se podrá asegurar que al utilizar este tipo de materiales, aliviará el impacto del costo global de las actividades, a pesar de tener alguna de ellas, costos individuales significativos. Y finalmente, se recomendará a constructores la implementación de este tipo de sistemas, los cuales favorecen los tiempos de ejecución de una obra y dan un parte de garantía al retorno de la inversión realizada en un corto plazo.This project is carried out in order to determine the influence of non-structural, corresponding to the partition walls and facade, in the seismic force and the cost of a building in reinforced concrete s. A building in Bogota was used, which was analyzed under different scenarios, using different types of materials to conform non-structural walls corresponding to partition walls and facade. Thus, you can determine how this variation affects the design of the elements of the structure and foundation, in terms of amounts of steel and concrete. In addition, you can ensure that when using these materials, ease the impact of the global cost of the activities, despite, some of them have a significant individual costs. Finally, recommend to builders the implementation of such systems, which give an advantage on the execution time of a work and give a guarantee of return on investment in the short term.Ingeniero (a) CivilPregrad
Energia hidrelétrica: projeções em um clima em mudança e impactos desta fonte
INTRODUCTION: Hydropower is an extensively used renewable source; in 2016, 159 countries reported benefiting; currently, there are around 9,000 projects in operation due to the competitive cost of generating a similar cost such as thermal energy such as coal, oil, or gas in the range of USD 4 - 5 cents US dollars per kilowatt-hour. OBJECTIVE: Investigate the results of hydroelectric development in the face of the changing climate and the generated impacts, making hydropower a subsector of special attention to discussing the global projection. METHOD: Bibliographic review to reflect on the global context of hydroelectricity based on scientific studies. RESULTS: Hydropower projects a 6% decrease for Europe by 2070, from 20% to 50% throughout the Mediterranean, and a reduction in usable capacity in most hydroelectric plants between 61% for the 2040 scenario– 2069 globally. DISCUSSION AND CONCLUSIONS: Globally, hydropower presents a broad vision of the advantages, and little said about the disadvantages and problems, and only there are specific studies that shown various project studied in a general way. It is shown that hydroelectric production has several implications in the face of the changing climate and impacts generated in ecosystems by the deployment of large infrastructures.Peer ReviewedPostprint (published version
An approach of the hydropower: advantages and impacts. A review
The present review shows a perspective of hydropower development, a renewable source that has a global installed capacity of 1308 GW with 9000 stations around the world. The document showed the advantages and the impacts around the different author’s perspectives. The review method consisted of defining a criterial find of articles, thesis and scientific material to consolidate the knowledge and give a viewpoint of this renewable source. The results show extensible affectations from hydropower expansion and this renewable energy source that requires analysis and study to delineate development sustainable with multidisciplinary areas of reflection. Moreover, the investigated results worldwide show that hydropower is not a pollution source; however, it has environmental impacts, social and cultural; such facilities may affect land, homes, and natural habitats. It concludes that the development of hydroelectric projects brings benefits but entails unavoidable impacts; therefore, it recommends that these affections must evaluate with detailed studies based on sustainability criteria.Peer ReviewedPostprint (published version
Asociación entre anemia ferropénica y parto pretérmino en mujeres de 15 a 49 años en Perú, según ENDES 2020
Identifica si la anemia
ferropénica es un factor de riesgo relacionado con el parto
pretérmino en mujeres de 15 a 49 años según datos “ENDES
2020”. La anemia ferropénica sigue siendo un problema de
salud pública en nuestro medio, siendo además causa de
complicaciones en grupos vulnerables como las gestantes. Dentro
de este grupo de complicaciones el parto prematuro cobra
relevancia debido a los costes públicos y secuelas a largo plazo
tanto para la madre como el feto. Se realizó un estudio transversal analítico a
partir de la información disponible en la basa de datos “ENDES
2020” del Instituto Nacional de Estadística e Informática (INEI). Los
datos fueron analizados por el software SPSS v25 para el análisis
de la correlación de Spearman. El 27.8% de
gestantes presentó anemia ferropénica, de las cuales solo el
64.09% recibió suplemento con sulfato ferroso de manera
adecuada; y el 8.5% de gestantes evaluadas presentaron parto
pretérmino. Se encontró un coeficiente de Spearman igual a 0.738,
el cual indica que existe una relación medianamente significativa
entre ambas variables. Se concluye que la anemia ferropénica es
considerado un factor de riesgo para el parto pretérmino
The American continent hydropower development and the sustainability: a review
The present review compares and takes the main ideas around hydropower development in eight countries of the American continent, identifying its advantages and disadvantages, showing a vision concerning sustainability. It is conclusive that there are impacts for each megawatt produced with hydropower, and the generation structure that uses the water resource of natural currents is not highly clean. Moreover, there is the mistaken criterion for developing a renewable hydropower project related to sustainability, a wrong approach, as demonstrated with the review. The examination in the eight countries of America some analyzes and the most concludes that, before considering a construction with thousands of dollars of investment and water contained in dams, the social and environmental analysis must respond to the restrictions on building new hydropower projects, promoting other unconventional renewable energy sources development. It is recommended to determine an objective quantitative approach of hydropower combining hydrology, energy efficiency, and interaction scenarios of future climate change to know the best energy grids diversifying balanced renewable and no renewable sources for each country.Peer ReviewedPostprint (published version
Are there really any AdS_2 branes in the euclidean (or not) AdS_3?
We do not find any AdS_2 branes, neither in the H_3^+ WZNW model nor the
SL(2,R) WZNW model. We then reexamine the case of the branes that possess a
su(2) symmetry: we speculate that they would have to live on the boundary of
AdS_3. This cannot be realized in an euclidean spacetime, but in the SL(2,R)
WZNW model by analytical continuation.Comment: 7 pages; v2: more explanation
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