Acetylcholine receptors in the human retina

International Nuclear Information System (INIS)

Hutchins, J.B.; Hollyfield, J.G.

1985-01-01

Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand 3 H-propylbenzilylcholine mustard ( 3 H-PrBCM) to label muscarinic receptors. 3 H- or 125 I-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic receptors are apparently present in the inner plexiform layer of the retina. Autoradiographic grain densities are reduced in the presence of saturating concentrations of atropine, quinuclidinyl benzilate or scopolamine; this indicates that 3 H-PrBCM binding is specific for a population of muscarinic receptors in the human retina. Binding sites for radiolabeled alpha-BTx are found predominantly in the inner plexiform layer of the retina. Grain densities are reduced in the presence of d-tubocurarine, indicating that alpha-BTx may bind to a pharmacologically relevant nicotinic ACh receptor. This study provides evidence for cholinergic neurotransmission in the human retina

Proyectos en la nube

OpenAIRE

Micó Tormos, Pau

2013-01-01

[ES] En este artículo se pretenden describir de forma clara las principales ventajas y los beneficios obtenidos al utilizar las herramientas ofrecidas en la nube para la elaboración de un proyecto docente de ámbito universitario Micó Tormos, P. (2013). Proyectos en la nube. Revista d'Innovació Docent Universitària. (5):62-69. http://hdl.handle.net/10251/29889 Senia 62 69 5

Rocas bajo el microscopio: acercamiento al estudio en lámina delgada de minerales y rocas

Directory of Open Access Journals (Sweden)

Patricia Acero Salazar

2013-01-01

Full Text Available En este trabajo se presenta una propuesta didáctica destinada a favorecer el acercamiento de los alumnos a una de las técnicas más habituales empleadas para el estudio de las rocas, sedimentos y minerales: la microscopía de luz polarizada. Para conseguir este objetivo, se proporciona a los alumnos un mínimo de conocimientos teóricos que les permite trabajar en grupos notablemente autónomos e identificar algunos de los componentes más frecuentes en distintos tipos de rocas y sedimentos. Con esta actividad, se familiariza a los estudiantes con algunas de las propiedades empleadas en microscopía óptica y con las propiedades de los propios componentes rocosos, y se proporcionan unas herramientas que facilitan el acercamiento a esta faceta del trabajo científico.

Proyecto de abastecimiento a Magallon

OpenAIRE

Pi Bartomeus, David

2012-01-01

Durante el período de Información Pública del “Proyecto de abastecimiento de agua a Zaragoza y su Entorno”, el Ayuntamiento de Magallón solicitó a la Confederación Hidrográfica del Ebro su inclusión en la red de abastecimiento citada. El objeto del presente proyecto es la definición de las obras necesarias para la inclusión del municipio de Magallón en el sistema de abastecimiento de agua a Zaragoza y su entorno. Dado que el objeto de este proyecto es la inclusión de Magallón e...

Proteomic interactions in the mouse vitreous-retina complex.

Directory of Open Access Journals (Sweden)

Jessica M Skeie

Full Text Available Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

Proteomic interactions in the mouse vitreous-retina complex.

Science.gov (United States)

Skeie, Jessica M; Mahajan, Vinit B

2013-01-01

Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina. Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software. We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor. Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

Selective retina therapy (SRT); Selektive Retina-Therapie (SRT)

Energy Technology Data Exchange (ETDEWEB)

Brinkmann, R.; Birngruber, R. [Luebeck Univ. (Germany). Inst. fuer Biomedizinische Optik; Medizinisches Laserzentrum Luebeck GmbH, Luebeck (Germany)

2007-07-01

Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

MI NIETZSCHE EN MÉXICO: HISTORIA DE UN ACERCAMIENTO

Directory of Open Access Journals (Sweden)

Herbert Frey

2014-01-01

Full Text Available El artículo presenta la historia del acercamiento del autor a Friedrich Nietzsche en el contexto del cambio de pa- radigmas en la interpretación internacional del filósofo alemán. Esta historia se teje a partir de la trayectoria vital del autor vinculada con sus distintos usos y apropiaciones de Nietzsche y su relación con América Latina. El autor concluye que en tanto un intérprete subraya determinados aspectos de una filosofía y le da menos valor a otros, se manifiesta a sí mismo y se interpreta a través del filósofo elegido.

Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter.

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Jake Bedore

Full Text Available Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina.A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5 deletion of VAChT (VAChTSix3-Cre-flox/flox and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses.This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina.

¿Espíritu visionario? Geo von Lengerke: proyectos comerciales y de caminos en la segunda mitad del siglo XIX

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Clara Inés Carreño Tarazona

2009-07-01

Full Text Available El trabajo presenta un acercamiento a la relación entre el llamado “sueño de promisión”, promovido por el gobierno federal en las últimas tres décadas del siglo xix, y el papel asignado al alemán Geo von Lengerke para ejecutar este propósito. Se destaca en un primer momento la forma como Lengerke utilizó su posición social y su carácter de foráneo para acceder, a partir de sus propios negocios, al monopolio de las vías comerciales. A continuación, se utiliza el término “sueño de promisión” para señalar que detrás de estos proyectos se consolidó un grupo de individuos vinculados a la explotación quinera, los pleitos, el poder y las influencias. Por último, se examinan los privilegios otorgados durante el proceso de apertura de rutas, especialmente aquellos relacionados con la obtención de títulos de propiedad sobre las tierras baldías cercanas a los caminos.

Information processing in the outer retina of fish

NARCIS (Netherlands)

Endeman, D.

2017-01-01

The retina translates light into neuronal activity. Thus, it renders visual information of the external environment. The retina can only send a limited amount of information to the brain within a given period. To use this amount optimally, light stimuli are strongly processed in the retina. This

An analog silicon retina with multichip configuration.

Science.gov (United States)

Kameda, Seiji; Yagi, Tetsuya

2006-01-01

The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study [1]. The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.

Guía de gestores de proyectos, setiembre 2012

OpenAIRE

Morante Milla, Antoni

2012-01-01

Què és un projecte?, La gestió de projectes, aspectes clau en la definició i gestió d'un projecte, planificació d'un projecte eines informàtiques per a la planificació i gestió de projectes i guia d'ús del programari de gestió de projectes ClockingIT. ¿Qué es un proyecto?, la gestión de proyectos, aspectos clave en la definición y gestión de un proyecto, planificación de un proyecto herramientas informáticas para la planificación y gestión de proyectos y guía de uso del software de gestión...

Acercamiento comunicativo dialógico-textual entre el docente de nivel medio superior del Instituto Politécnico Nacional y el científico.

OpenAIRE

Flores Cervantes, Claudia

2015-01-01

La educación del siglo XXI enfrenta retos relacionados con la digitalización, las políticas gubernamentales, la profesionalización docente, la vinculación, la calidad, evaluaciones internacionales, e incluso, el acercamiento de la ciencia y la tecnología a los contenidos curriculares, a partir de la combinación de conocimientos prácticos y teóricos (UNESCO, 1998). En México se destaca el acercamiento, manejo y transmisión de contenidos científicos y tecnológicos a la vida escolar; en la Refor...

The retina

DEFF Research Database (Denmark)

van Reyk, David M; Gillies, Mark C; Davies, Michael Jonathan

2003-01-01

A prominent and early feature of the retinopathy of diabetes mellitus is a diffuse increase in vascular permeability. As the disease develops, the development of frank macular oedema may result in vision loss. That reactive oxygen species production is likely to be elevated in the retina, and tha...

The infrared retina

International Nuclear Information System (INIS)

Krishna, Sanjay

2009-01-01

As infrared imaging systems have evolved from the first generation of linear devices to the second generation of small format staring arrays to the present 'third-gen' systems, there is an increased emphasis on large area focal plane arrays (FPAs) with multicolour operation and higher operating temperature. In this paper, we discuss how one needs to develop an increased functionality at the pixel level for these next generation FPAs. This functionality could manifest itself as spectral, polarization, phase or dynamic range signatures that could extract more information from a given scene. This leads to the concept of an infrared retina, which is an array that works similarly to the human eye that has a 'single' FPA but multiple cones, which are photoreceptor cells in the retina of the eye that enable the perception of colour. These cones are then coupled with powerful signal processing techniques that allow us to process colour information from a scene, even with a limited basis of colour cones. Unlike present day multi or hyperspectral systems, which are bulky and expensive, the idea would be to build a poor man's 'infrared colour' camera. We use examples such as plasmonic tailoring of the resonance or bias dependent dynamic tuning based on quantum confined Stark effect or incorporation of avalanche gain to achieve embodiments of the infrared retina.

Proyecto innovador: “con+ciencia”

OpenAIRE

Fernández Arroyo, Jorge; Rodríguez Marín, Fátima; González Medina, Sara

2013-01-01

En esta comunicación se expone la experiencia de observación sobre el funcionamiento del proyecto Con+ciencia en los cursos de 5º y 6º de Primaria (tercer ciclo) del centro C.E.I.P. “Príncipe de Asturias” (Sevilla) durante el mes de marzo del 2013. Nuestra participación ha buscado conocer en profundidad este proyecto, observar su aplicación real en el aula y sus implicaciones en el alumnado y el profesorado.

Migración internacional y ciencia histórica: un acercamiento desde la nueva historia

Directory of Open Access Journals (Sweden)

Eduardo Fernández Guzmán

2017-12-01

Full Text Available En el siglo XX asistimos a una continua revisión de los presupuestos epistemológicos y metodológicos del quehacer historiográfico. Fuertes sacudidas sufrieron las visiones positivistas, muy tradicionalistas y reduccionistas en los enfoques, abriendo nuevas perspectivas en cuanto a las fuentes, la temática, las personalidades, los acontecimientos, los tiempos históricos, la objetividad, las escalas. Se problematizó en cuanto a su alcance, legitimidad, el diálogo interdisciplinario, las estructuras que se vinculan en su devenir, la cualidad sintética. Cambio que ha propiciado un acercamiento a lo subalterno, los de abajo, lo microhistórico, lo cotidiano, a la experiencia contemporánea desde la perspectiva de la memoria y lo vivido de los sin voz. La migración internacional como un fenómeno social que afecta a amplios sectores subalternos de la sociedad se ha visto favorecida de esta renovación historiográfica. Nuestro objetivo es hacer un acercamiento teórico preliminar de la historia como ciencia y la migración internacional contemporánea, y en particular la de México- Estados Unidos.

Retina neural circuitry seen with particle detector technology

CERN Multimedia

CERN Bulletin

2010-01-01

Using particle physics techniques, high energy physics researchers have recently provided new insight into neural circuits inside the retina. After uncovering a new type of retinal cell and mapping how the retina deals with colours, the team from Santa Cruz (US), Krakow and Glasgow is now turning its attention to more complex issues such as how the retina gets wired up and how the brain deals with the signals it receives from the retina. All this using technology derived from high-density, multistrip silicon detectors…   Seen from the point of view of a particle physicist, eyes are image detectors that can gather many different types of data: light and dark, different colours, motion, etc. In particular, the retina, a thin tissue that lines the back of the eye, is a biological pixel detector that detects light and converts it to electrical signals that travel through the optic nerve to the brain. Neurobiologists know that many different cell types are involved in these processes, but they...

Propuesta de docencia en la asignatura de Proyectos y Proyectos Fin de Carrera en el nuevo Marco Europeo en Ingeniería de Telecomunicación

OpenAIRE

Álvarez Vaquero, Francisco; Alonso Montes, José Ignacio

2007-01-01

La propuesta de innovacion docente que se pondrá en marcha en la asignatura de Proyectos de 5º curso de Ingeniería de Telecomunicación y en la realización de los Proyectos Fin de Carrera consiste en que los alumnos de quinto curso pueden efectuar el visado de un proyecto elaborado en la asignatura de proyectos de último curso y de su proyecto fin de carrera, siguiendo un procedimiento similar al que realizan los ingenieros de telecomunicación con la firma y visado de trabajos y...

Metodología de gestión de proyectos para la división de infraestructura y proyectos del Banco Popular

OpenAIRE

Ruiz-Moya, José Vidal

2015-01-01

Proyecto de graduación (Maestría en Gerencia de Proyectos) Instituto Tecnológico de Costa Rica, Área Académica de Gerencia de Proyectos, 2015. The Division of infrastructure projects of Banco Popular has among its main functions to manage the institutional infrastructure projects, manage and administer the institutional maintenance of buildings and lease expiration control contracts for leased premises; directing the efforts of these areas to objectives of the Directorate of Administrative...

Proyecto y construcción de restaurantes modulares: "Proyecto Diner"

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Seco Femández, Enrique

2002-04-01

Full Text Available In this article the results of the called "Diner Project" are presented. This project develops the design, construction and the complete equipment of a restaurant built in a factory, including the transportation to its final place. This finished building is composed of a single or everal modules joint together. The only requirement to be done on site is to build the foundations and lo connet the modules with the public services.En este artículo se presentan los resultados del denominado "Proyecto Diner". Este proyecto desarrolla el diseño, la construcción y el equipamiento completo de un restaurante en factoría, que posteriormente se transporta y localiza en su ubicación definitiva. El edificio terminado se compone de un módulo individual o bien de varios unidos entre sí, que sólo requieren en obra la realización de una cimentación y la conexión a las instalaciones públicas.

Desarrollo de herramienta de gestión de proyectos RUP usando metodologías Scrum + XP : gestión del proyecto y requisitos

OpenAIRE

Molina Romero, Javier; Quishpi Betún, Luis

2016-01-01

Una de las principales causas por las que los proyectos de desarrollo software fracasan es la ausencia de metodología en su desarrollo. La motivación que hay detrás de este proyecto es el desarrollo de una aplicación web usando la metodología Rational Unified Process (RUP) y aprender, en una situación real, cómo desarrollar utilizando las metodologías Scrum + XP. El principal objetivo de este proyecto es el seguimiento y documentación de una aplicación web para gestionar proyectos mediant...

Modelo de gestión del tiempo en proyectos viales.

OpenAIRE

Luzuriaga Bojorque, Juan Pablo

2015-01-01

El presente trabajo demuestra la importancia de utilizar un método internacionalmente reconocido para gestionar la terminación de los proyectos viales a tiempo. Tanto entidad contratante como contratistas podrán utilizar las mejores prácticas en gerenciamiento de proyectos para lograr que la construcción de carreteras sean proyectos exitosos. Las entidades contratantes en el Ecuador, evalúan el cumplimiento del cronograma de un proyecto vial, en base de la consecución de un nivel determinado ...

Radioadaptive Cytoprotective Pathways in the Mouse Retina

Science.gov (United States)

Zanello, Susana B.; Wotring, V.; Theriot, C.; Ploutz-Snyder, R.; Zhang, Y.; Wu, H.

2010-01-01

Exposure to cosmic radiation implies a risk of tissue degeneration. Radiation retinopathy is a complication of radiotherapy and exhibits common features with other retinopathies and neuropathies. Exposure to a low radiation dose elicits protective cellular events (radioadaptive response), reducing the stress of a subsequent higher dose. To assess the risk of radiation-induced retinal changes and the extent to which a small priming dose reduces this risk, we used a mouse model exposed to a source of Cs-137-gamma radiation. Gene expression profiling of retinas from non-irradiated control C57BL/6J mice (C) were compared to retinas from mice treated with a low 50 mGy dose (LD), a high 6 Gy dose (HD), and a combined treatment of 50 mGy (priming) and 6 Gy (challenge) doses (LHD). Whole retina RNA was isolated and expression analysis for selected genes performed by RTqPCR. Relevant target genes associated with cell death/survival, oxidative stress, cellular stress response and inflammation pathways, were analyzed. Cellular stress response genes were upregulated at 4 hr after the challenge dose in LHD retinas (Sirt1: 1.5 fold, Hsf1: 1.7 fold, Hspa1a: 2.5 fold; Hif1a: 1.8 fold, Bag1: 1.7). A similar trend was observed in LD animals. Most antioxidant enzymes (Hmox1, Sod2, Prdx1, Cygb, Cat1) and inflammatory mediators (NF B, Ptgs2 and Tgfb1) were upregulated in LHD and LD retinas. Expression of the pro-survival gene Bcl2 was upregulated in LD (6-fold) and LHD (4-fold) retinas. In conclusion, cytoprotective gene networks activation in the retina suggests a radioadaptive response to a priming irradiation dose, with mitigation of the deleterious effects of a subsequent high dose exposure. The enhancement of these cytoprotective mechanisms has potential value as a countermeasure to ocular alterations caused by radiation alone or in combination with other factors in spaceflight environments.

Retina image–based optic disc segmentation

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Ching-Lin Wang

2016-05-01

Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

Almacenamiento de energía mediante aire comprimido: Plantas CAES.

OpenAIRE

Muñoz Diez de la Cortina, Alejandro

2015-01-01

El presente proyecto estudia el estado del arte en cuanto a tecnología CAES se refiere, en un intento de compilación de la información disponible en distintos medios de divulgación científica e ingenieril, y haciendo una presentación de las distintas mejoras y desarrollos posibles de la tecnología así como de un acercamiento a las dos plantas ya existentes que utilizan este medio de almacenamiento de energía. El núcleo del proyecto se encuentra en el estudio de los sistemas ...

El comercio exterior durante la década revolucionaria: un acercamiento preliminar

OpenAIRE

Sandra Kuntz Ficker

2001-01-01

El propósito de este trabajo es realizar un primer acercamiento sistemático al análisis del comercio exterior de México durante la década de 1910. Tal objetivo se ha visto obstaculizado en el pasado por la escasez de fuentes cuantitativas de procedencia mexicana para los años de la revolución. Para suplir esta carencia, este artículo recurre a las estadísticas comerciales publicadas por los principales socios de México durante estos años (Estados Unidos, Gran Bretaña y Francia). A pa...

Imaging of the peripheral retina

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Marcus Kernt

2013-01-01

Full Text Available The technical progress of the recent years has revolutionized imaging in ophthalmology. Scanning laser ophthalmoscopy (SLO, digital angiography, optical coherence tomography (OCT, and detection of fundus autofluorescence (FAF have fundamentally changed our understanding of numerous retinal and choroidal diseases. Besides the tremendous advances in macular diagnostics, there is more and more evidence that central pathologies are often directly linked to changes in the peripheral retina. This review provides a brief overview on current posterior segment imaging techniques with a special focus on the peripheral retina.

PROYECTOS DE I+D, CARACTERIZACIÓN DEL TIPO DE INVESTIGACIÓN Y EL ROL DE GERENTE DE PROYECTOS

Directory of Open Access Journals (Sweden)

Aníbal N. Cassanelli

2014-12-01

Full Text Available En este artículo se pone de manifiesto la importancia del sector de la I+D y su organización fuertemente proyectizada que la convierte en un área clave para la aplicación de metodologías de gestión de proyectos. Se analizan los modelos de procesos de la I+D para proponer un esquema basado en dominios interrelacionados que permite dar pie a la identificación y caracterización de la investigación básica, aplicada, desarrollo e innovación. A partir de ahí, se comparan las competencias entre el gestor de proyectos general y los investigadores principales (gestores de proyectos de I+D de facto. Se concluye que existe una gran diferencia entre conocimientos y competencias requeridos para la gestión. Se muestran las dos tendencias que existen en el sector de I+D y la propuesta de separación del roles y la creación de una nueva figura distintiva del investigador principal que se ocupe de la gestión de proyectos.

Imagen de retina de campo ultra-amplio

Directory of Open Access Journals (Sweden)

Gerardo García-Aguirre

2017-11-01

Conclusión: Las imágenes de campo ultra-amplio han revolucionado la forma en la que estudiamos y entendemos la enfermedad de la retina. A medida que la tecnología para obtenerlas se haga más accesible, formará parte del armamentario de rutina para estudiar las enfermedades de la retina.

Topography of ganglion cell production in the cat's retina

International Nuclear Information System (INIS)

Walsh, C.; Polley, E.H.

1985-01-01

The ganglion cells of the cat's retina form several classes distinguishable in terms of soma size, axon diameter, dendritic morphology, physiological properties, and central connections. Labeling with [ 3 H]thymidine shows that the ganglion cells which survive in the adult are produced as several temporally shifted, overlapping waves: medium-sized cells are produced before large cells, whereas the smallest ganglion cells are produced throughout the period of ganglion cell generation. Large cells and medium-sized cells show the same distinctive pattern of production, forming rough spirals around the area centralis. The oldest cells tend to lie superior and nasal to the area centralis, whereas cells in the inferior nasal retina and inferior temporal retina are, in general, progressively younger. Within each retinal quadrant, cells nearer the area centralis tend to be older than cells in the periphery, but there is substantial overlap. The retinal raphe divides the superior temporal quadrant into two zones with different patterns of cell addition. Superior temporal retina near the vertical meridian adds cells only slightly later than superior nasal retina, whereas superior temporal retina near the horizontal meridian adds cells very late, contemporaneously with inferior temporal retina. The broader wave of production of smaller ganglion cells seems to follow this same spiral pattern at its beginning and end. The presence of the area centralis as a nodal point about which ganglion cell production in the retinal quadrants pivots suggests that the area centralis is already an important retinal landmark even at the earliest stages of retinal development

"El proyecto PARTEA: una experiencia educativa para el desarrollo del diálogo intercultural en Europa" [PARTEA project: an educational experience to develop intercultural dialogue in Europe

Directory of Open Access Journals (Sweden)

Juan Rafael Hernández Bravo

2011-01-01

Full Text Available RESUMEN:El proyecto PARTEA (Padres y Profesores: compañeros en el diálogo intercultural ha sido una experiencia educativa desarrollada en siete países de Europa (España, Dinamarca, Reino Unido, Bélgica, Grecia, Turquía y Rumanía, cuyo objetivo principal ha sido el de identificar y desarrollar métodos en el ámbito escolar para mejorar el diálogo intercultural entre padres de las culturas minoritarias y profesores de los diferentes países europeos participantes en este proyecto. Este proyecto ha sido financiado por el Programa de Aprendizaje Permanente de la Comisión Europea y se ha llevado a cabo durante los cursos académicos 2009 y 2011. Durante el periodo en el que se desarrolló la experiencia, se comprobó la necesidad de mejorar el diálogo intercultural entre los miembros de las comunidades educativas, constatándose que el acercamiento entre padres de diferentes culturas y profesores contribuía al incremento de dicho diálogo. De esta manera, el proyecto ha supuesto también una oportunidad para el intercambio de buenas prácticas educativas entre docentes y el establecimiento de nuevos canales de comunicación e interacción con las familias de diferentes culturas en el marco de una Europa culturalmente diversa.ABSTRACT:The PARTEA project (Parents and Teachers: Partners in intercultural dialogue has been an educational experience developed in seven European countries (Spain, Denmark, the United Kingdom, Belgium, Greece, Turkey and Romania, whose main objective was to identify and develop methods in schools to improve intercultural dialogue among parents of minority cultures and teachers from the different European countries participating in this project. This project, which was funded by the Lifelong Learning Programme of the European Commission, was carried out during two academic years, between 2009 and 2011. Throughout the life-time of the project, we found the need to improve intercultural dialogue among the members of

Helping the Retina Regenerate

Science.gov (United States)

... the retina News Brief 03/30/17 A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored ...

"Diagnóstico de madurez organizacional en gestión de proyectos y propuesta base de una oficina de proyectos en una empresa de sistemas de información"

OpenAIRE

Giraldo-Álvarez, Gloria

2011-01-01

Proyecto de Graduación (Maestría en Gerencia de Proyectos Empresariales y Gerencia de Proyectos de Tecnología de Información) Instituto Tecnológico de Costa Rica. Área acádemica de Gerencia de Proyectos,. Escuela de Administración de Empresas, 2011. ABC (1) es una empresa costarricense especializada en tecnología de información que se encuentra en un proceso de expansión y le interesa de contar con una cultura organizacional orientada a la gestión de proyectos. Con la finalidad de...

Meduloepitelioma teratóide da retina: relato de caso Teratoid medulloepithelioma of the retina: case report

Directory of Open Access Journals (Sweden)

Ramon Coral Ghanem

2004-06-01

Full Text Available O meduloepitelioma é um tumor intra-ocular congênito originário do epitélio medular primitivo que, por sua vez, é responsável pela formação do epitélio não pigmentado do corpo ciliar. Ocorre geralmente na infância, de forma unilateral, acometendo o corpo ciliar. O objetivo deste trabalho é documentar um caso raro de meduloepitelioma teratóide originário da retina. Paciente de nove anos, feminina, apresentava baixa acuidade visual (AV, estrabismo e leucocoria no olho esquerdo (OE. A AV era de 1,0 no olho direito e movimentos de mão no OE. Foi observada tumoração retrocristaliniana branco-acinzentada no OE, aparentemente subretiniana, vascularizada, de grande extensão, com alterações císticas na sua superfície. Foram realizadas tomografia de crânio e órbitas e ecografia ocular. A paciente foi submetida à enucleação com suspeita clínica de retinoblastoma. Pelo aspecto histopatológico foi feito o diagnóstico de meduloepitelioma teratóide benigno originário da retina. Na maioria dos casos apresentados na literatura o meduloepitelioma tem origem a partir do epitélio não pigmentado do corpo ciliar. No nosso caso, a neoplasia parece ter tido origem a partir da retina, já que os cortes revelaram epitélio do corpo ciliar preservado e não foi reconhecida a estrutura normal da retina. Embora o tumor apresentado neste relato tenha sido classificado como benigno, o fato de ser lesão de grandes proporções e de crescimento aparentemente recente, justifica a conduta cirúrgica empregada. O tratamento do meduloepitelioma deve objetivar a intervenção cirúrgica precoce, na tentativa de se evitar a disseminação extra-ocular.Medulloepithelioma is a congenital intraocular tumor that usually arises from the primitive medullary epithelium that is destined to form the nonpigmented ciliary epithelium of the ciliary body. It occurs most frequently in early childhood and is unilateral. This report documents a rare case of

Why has Nature Chosen Lutein and Zeaxanthin to Protect the Retina?

OpenAIRE

Widomska, Justyna; Subczynski, Witold K

2014-01-01

Age-related macular degeneration (AMD) is associated with a low level of macular carotenoids in the eye retina. Only two carotenoids, namely lutein and zeaxanthin are selectively accumulated in the human eye retina from blood plasma where more than twenty other carotenoids are available. The third carotenoid which is found in the human retina, meso-zeaxanthin is formed directly in the retina from lutein. All these carotenoids, named also macular xanthophylls, play key roles in eye health and ...

Rhythmic ganglion cell activity in bleached and blind adult mouse retinas.

Science.gov (United States)

Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

2014-01-01

In retinitis pigmentosa--a degenerative disease which often leads to incurable blindness--the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor's dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the understanding of the degeneration process and may guide future rescue strategies.

Diez pasos para el aprendizaje complejo: Un acercamiento sistemático al diseňo instruccional de los cuatro componentes

NARCIS (Netherlands)

Van Merriënboer, Jeroen; Kirschner, Paul A.

2011-01-01

Van Merriënboer, J. J. G., & Kirschner, P. A. (2010). Diez pasos para el aprendizaje complejo: Un acercamiento sistemático al diseňo instruccional de los cuatro componentes (translation from English). Cuajimalpa, México: Aseguramiento de la Calidad en la Educacion y en el Trabajo.

[Degenerative lesions of the peripheral retina].

Science.gov (United States)

Conart, J-B; Baron, D; Berrod, J-P

2014-01-01

Degenerative lesions of the peripheral retina are present from teenage years onwards and increase with age. These abnormabilities are frequent, some of them being benign while others predispose to retinal tears and detachment. In the latter case, the lesions are rhegmatogenous and may justify prophylactic treatment by laser photocoagulation. We distinguish congenital lesions of the peripheral retina and intraretinal, chorioretinal and vitreoretinal degenerations. The holes and tears observed in 2% of the population consist of round atrophic holes, "horseshoe" tears, oral dialyses and giant tears. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

FPGA-Based Real Time, Multichannel Emulated-Digital Retina Model Implementation

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Zsolt Vörösházi

2009-01-01

Full Text Available The function of the low-level image processing that takes place in the biological retina is to compress only the relevant visual information to a manageable size. The behavior of the layers and different channels of the neuromorphic retina has been successfully modeled by cellular neural/nonlinear networks (CNNs. In this paper, we present an extended, application-specific emulated-digital CNN-universal machine (UM architecture to compute the complex dynamic of this mammalian retina in video real time. The proposed emulated-digital implementation of multichannel retina model is compared to the previously developed models from three key aspects, which are processing speed, number of physical cells, and accuracy. Our primary aim was to build up a simple, real-time test environment with camera input and display output in order to mimic the behavior of retina model implementation on emulated digital CNN by using low-cost, moderate-sized field-programmable gate array (FPGA architectures.

Neurotransmitter properties of the newborn human retina

International Nuclear Information System (INIS)

Hollyfield, J.G.; Frederick, J.M.; Rayborn, M.E.

1983-01-01

Human retinal tissue from a newborn was examined autoradiographically for the presence of high-affinity uptake and localization of the following putative neurotransmitters: dopamine, glycine, GABA, aspartate, and glutamate. In addition, the dopamine content of this newborn retina was measured by high pressure liquid chromatography. Our study reveals that specific uptake mechanisms for 3 H-glycine, 3 H-dopamine, and 3 H-GABA are present at birth. However, the number and distribution of cells labeled with each of these 3 H-transmitters are not identical to those observed in adult human retinas. Furthermore, the amount of endogenous dopamine in the newborn retina is approximately 1/20 the adult level. Photoreceptor-specific uptake of 3 H-glutamate and 3 H-aspartate are not observed. These findings indicate that, while some neurotransmitter-specific properties are present at birth, significant maturation of neurotransmitter systems occurs postnatally

A digital retina-like low-level vision processor.

Science.gov (United States)

Mertoguno, S; Bourbakis, N G

2003-01-01

This correspondence presents the basic design and the simulation of a low level multilayer vision processor that emulates to some degree the functional behavior of a human retina. This retina-like multilayer processor is the lower part of an autonomous self-organized vision system, called Kydon, that could be used on visually impaired people with a damaged visual cerebral cortex. The Kydon vision system, however, is not presented in this paper. The retina-like processor consists of four major layers, where each of them is an array processor based on hexagonal, autonomous processing elements that perform a certain set of low level vision tasks, such as smoothing and light adaptation, edge detection, segmentation, line recognition and region-graph generation. At each layer, the array processor is a 2D array of k/spl times/m hexagonal identical autonomous cells that simultaneously execute certain low level vision tasks. Thus, the hardware design and the simulation at the transistor level of the processing elements (PEs) of the retina-like processor and its simulated functionality with illustrative examples are provided in this paper.

Optimización en las decisiones de financiamiento de proyectos

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Felipe Tomás Muñoz Valdés

2003-07-01

Full Text Available La finalidad de este trabajo es aplicar herramientas de optimización a las decisiones de financiamiento de proyectos de inversión, más específicamente, cómo mejorar el valor actual de un proyecto eligiendo la combinación óptima de fuentes de financiamiento. El carácter de largo plazo de las inversiones de un proyecto exige investigar las opciones de financiamiento para el proyecto, y no cabe duda que mientras más convenientes sean las condiciones que se logren, más atractivo será el proyecto. La búsqueda de la forma de financiar un proyecto de inversión, puede dar como resultado una variedad bastante importante de opciones diferentes. Esta información es de mucha utilidad para el inversionista, porque le permite determinar cómo financiar el proyecto, es decir, cuánto capital propio debe invertir en el proyecto y cómo debe financiar el monto restante de la inversión. Los métodos y modelos que se usan actualmente en esta toma de decisiones tienen deficiencias. Una de las deficiencias más importantes de estos métodos es que suponen que en todos los periodos se tienen utilidades antes de impuestos, calculando impuestos sobre las pérdidas antes de impuesto. También presentan dificultades cuando se tienen muchas alternativas de financiamiento y no permiten buscar combinaciones entre fuentes de financiamiento. A medida que aumenta la cantidad y características de las fuentes de financiamiento, aumenta la cantidad de cálculos de valor actual que se deben realizar, por lo que la aplicación de estas herramientas requiere una gran cantidad de tiempo. Para resolver el problema se recurrió a la teoría económica de Preparación de Proyectos, Evaluación de Proyectos y Programación Matemática, más específicamente a la Programación Mixta, que es una mezcla de Programación Lineal y Programación Entera. El procedimiento que se empleó para desarrollar el modelo de programación matemática, comenzó con la identificación de

The mammalian retina as a clock

Science.gov (United States)

Tosini, Gianluca; Fukuhara, Chiaki

2002-01-01

Many physiological, cellular, and biochemical parameters in the retina of vertebrates show daily rhythms that, in many cases, also persist under constant conditions. This demonstrates that they are driven by a circadian pacemaker. The presence of an autonomous circadian clock in the retina of vertebrates was first demonstrated in Xenopus laevis and then, several years later, in mammals. In X. laevis and in chicken, the retinal circadian pacemaker has been localized in the photoreceptor layer, whereas in mammals, such information is not yet available. Recent advances in molecular techniques have led to the identification of a group of genes that are believed to constitute the molecular core of the circadian clock. These genes are expressed in the retina, although with a slightly different 24-h profile from that observed in the central circadian pacemaker. This result suggests that some difference (at the molecular level) may exist between the retinal clock and the clock located in the suprachiasmatic nuclei of hypothalamus. The present review will focus on the current knowledge of the retinal rhythmicity and the mechanisms responsible for its control.

Selective retina therapy (SRT)

International Nuclear Information System (INIS)

Brinkmann, R.; Birngruber, R.

2007-01-01

Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

Expression of nitric oxide synthase during the development of RCS rat retinas.

Science.gov (United States)

Sharma, R K; Warfvinge, K; Ehinger, B

2001-01-01

Nitric oxide (NO) has been reported to be both neurodestructive and neuroprotective in the central nervous system and could possibly play an important role in neurodegenerative disorders. On the assumption that NO synthesis may influence degenerative processes in the retina, we have examined the development and distribution of nitric-oxide-synthase(NOS)-immunoreactive cells in developing Royal College of Surgeons (RCS) rat retinas, which is an animal model for retinal degeneration. An antibody against constitutive neuronal NOS was used for immunocytochemistry on RCS rat retinas from postnatal (PN) days 3, 7, 10, 14, 35, 70 and 281 and compared with that in the normal rats of PN days 3, 7, 10, 14, 54 and adults. Immunoreactive cells were not seen in PN 3 retinas but were distinctly seen in the PN 7 retina along with a plexus in the inner plexiform layer. In both groups (normal and RCS rats) a distinct sublayering of the plexus in the inner plexiform layer could be seen at PN 10, which became more distinct at PN 14. The immunoreactive cells were detected also in the oldest retina examined, which was PN 281 in the case of RCS rats. In both groups, certain amacrine cells, certain bipolar cells and certain horizontal cells were found to be immunoreactive. In conclusion, the developmental timetable of the NOS immunoreactivity was identical in the normal and the RCS rat retinas. The NOS-immunoreactive cells persisted in the RCS retinas even when the retina had degenerated extensively. Abnormalities with the inducible isoforms of NOS cannot be ruled out from this study. We conclude that the chronological and qualitative development of the constitutive neuronal NOS immunoreactivity is normal in RCS rat retinas. Copyright 2001 S. Karger AG, Basel

Estrategias orientadoras apara la elaboración de proyectos de adultos mayores

OpenAIRE

Ciano, Natalia

2011-01-01

En este trabajo se presenta el proyecto de investigación "estrategias orientadoras para la elaboración de proyectos en adultos mayores" que se propone aplicar las estrategias orientadoras diseñadas en un proyecto anterior a los efectos de analizar el impacto de las mismas en la elaboración de proyectos de adultos mayores. Articula el Modelo de Envejecimiento Activo y el Modelo Teórico Operativo en Orientación. Se parte de los principales resultados obtenidos en la investigación anterior, los ...

Real-time simulation of the retina allowing visualization of each processing stage

Science.gov (United States)

Teeters, Jeffrey L.; Werblin, Frank S.

1991-08-01

The retina computes to let us see, but can we see the retina compute? Until now, the answer has been no, because the unconscious nature of the processing hides it from our view. Here the authors describe a method of seeing computations performed throughout the retina. This is achieved by using neurophysiological data to construct a model of the retina, and using a special-purpose image processing computer (PIPE) to implement the model in real time. Processing in the model is organized into stages corresponding to computations performed by each retinal cell type. The final stage is the transient (change detecting) ganglion cell. A CCD camera forms the input image, and the activity of a selected retinal cell type is the output which is displayed on a TV monitor. By changing the retina cell driving the monitor, the progressive transformations of the image by the retina can be observed. These simulations demonstrate the ubiquitous presence of temporal and spatial variations in the patterns of activity generated by the retina which are fed into the brain. The dynamical aspects make these patterns very different from those generated by the common DOG (Difference of Gaussian) model of receptive field. Because the retina is so successful in biological vision systems, the processing described here may be useful in machine vision.

Proyecto constructivo de la EDAR de Harsova, Rumanía

OpenAIRE

Lloret Batlle, Roger

2012-01-01

El objeto del presente proyecto consiste en la definición precisa de las obras que requerirá la construcción de la EDAR de Harsova. La razón de ser y justificación del proyecto se hace patente ante la necesidad social, medio ambiental y de salubridad de poner fin a los vertidos de aguas residuales sin tratar al cauce público. Es evidente, por tanto, la urgencia de un proyecto de Estación Depuradora de Aguas Residuales (EDAR) para el municipio con una línea de tratamiento ade...

Tu proyecto de vida

OpenAIRE

Ramos, Georgina

2012-01-01

- Párrafo Inicial - Conociendo a Liliana N. - La intervención de la psicóloga Adriana - Tu proyecto de vida - Referencias - Notas de enseñanza o Resumen o Objetivos o Temas relacionados o Plan de aplicación para el aprendizaje o Análisis o Epílogo

Functional Architecture of the Retina: Development and Disease

Science.gov (United States)

Hoon, Mrinalini; Okawa, Haruhisa; Santina, Luca Della; Wong, Rachel O.L.

2014-01-01

Structure and function are highly correlated in the vertebrate retina, a sensory tissue that is organized into cell layers with microcircuits working in parallel and together to encode visual information. All vertebrate retinas share a fundamental plan, comprising five major neuronal cell classes with cell body distributions and connectivity arranged in stereotypic patterns. Conserved features in retinal design have enabled detailed analysis and comparisons of structure, connectivity and function across species. Each species, however, can adopt structural and/or functional retinal specializations, implementing variations to the basic design in order to satisfy unique requirements in visual function. Recent advances in molecular tools, imaging and electrophysiological approaches have greatly facilitated identification of the cellular and molecular mechanisms that establish the fundamental organization of the retina and the specializations of its microcircuits during development. Here, we review advances in our understanding of how these mechanisms act to shape structure and function at the single cell level, to coordinate the assembly of cell populations, and to define their specific circuitry. We also highlight how structure is rearranged and function is disrupted in disease, and discuss current approaches to re-establish the intricate functional architecture of the retina. PMID:24984227

Modeling laser damage to the retina

Science.gov (United States)

Clark, Clifton D.

This dissertation presents recent progress in several areas related to modeling laser damage to the retina. In Chapter 3, we consider the consequences of using the Arrhenius damage model to predict the damage thresholds of multiple pulse, or repetitive pulse, exposures. We have identified a few fundamental trends associated with the multiple pulse damage predictions made by the Arrhenius model. These trends differ from what would be expected by non-thermal mechanisms, and could prove useful in differentiating thermal and non-thermal damage. Chapter 4 presents a new rate equation damage model hypothesized to describe photochemical damage. The model adds a temperature dependent term to the simple rate equation implied by the principle of reciprocity that is characteristic of photochemical damage thresholds. A recent damage threshold study, conducted in-vitro, has revealed a very sharp transition between thermal and photochemical damage threshold trends. For the wavelength used in the experiment (413 nm), thermal damage thresholds were observed at exposure levels that were twice the expected photochemical damage threshold, based on the traditional understanding of photochemical damage. Our model accounts for this observed trend by introducing a temperature dependent quenching, or repair, rate to the photochemical damage rate. For long exposures that give a very small temperature rise, the model reduces to the principle of reciprocity. Near the transition region between thermal and photochemical damage, the model allows the damage threshold to be set by thermal mechanisms, even at exposure above the reciprocity exposure. In Chapter 5, we describe a retina damage model that includes thermal lensing in the eye by coupling beam propagation and heat transfer models together. Thermal lensing has recently been suggested as a contributing factor to the large increase in measured retinal damage thresholds in the near infrared. The transmission of the vitreous decreases

The ciliary margin zone of the mammalian retina generates retinal ganglion cells

Science.gov (United States)

Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

2016-01-01

Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

Illumination-invariant face recognition with a contrast sensitive silicon retina

Energy Technology Data Exchange (ETDEWEB)

Buhmann, J.M. [Rheinische Friedrich-Wilhelms-Univ., Bonn (Germany). Inst. fuer Informatik II; Lades, M. [Bochum Univ. (Germany). Inst. fuer Neuroinformatik; Eeckman, F. [Lawrence Livermore National Lab., CA (United States)

1993-11-29

Changes in lighting conditions strongly effect the performance and reliability of computer vision systems. We report face recognition results under drastically changing lighting conditions for a computer vision system which concurrently uses a contrast sensitive silicon retina and a conventional, gain controlled CCD camera. For both input devices the face recognition system employs an elastic matching algorithm with wavelet based features to classify unknown faces. To assess the effect of analog on-chip preprocessing by the silicon retina the CCD images have been digitally preprocessed with a bandpass filter to adjust the power spectrum. The silicon retina with its ability to adjust sensitivity increases the recognition rate up to 50 percent. These comparative experiments demonstrate that preprocessing with an analog VLSI silicon retina generates image data enriched with object-constant features.

Maturação funcional da retina em bebês prematuros

Directory of Open Access Journals (Sweden)

Adriana Berezovsky

2007-06-01

Full Text Available A retina humana ainda não está totalmente desenvolvida no nascimento. Só após o nascimento é que ocorrem mudanças anatômicas como o aumento na densidade de cones centrais e o alongamento do segmento externo dos fotorreceptores. As mudanças funcionais que ocorrem na retina com a maturação no primeiro ano de vida podem ser avaliadas pela técnica do eletrorretinograma de campo total, que representa a atividade somada da retina distal em resposta à luz. Abordaremos aspectos da maturação funcional da retina avaliada pelo eletrorretinograma em bebês prematuros.

Connecting the Retina to the Brain

Directory of Open Access Journals (Sweden)

Lynda Erskine

2014-12-01

Full Text Available The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.

P+C : Proyecto y Ciudad : revista de temas de arquitectura. Número 8

OpenAIRE

Laborda Yneva, José Eulalio

2017-01-01

Proyecto y Ciudad es una revista científica que publica artículos originales y difunde la intención programática y expresiva del Grupo de Investigación ‘Proyecto y Ciudad’, desde el Área de Proyectos Arquitectónicos de la Universidad Politécnica de Cartagena. La revista está dedicada a la investigación, análisis y crítica sobre temas relacionados con la Arquitectura, entendida ésta como un acto complejo y amplio que reúne pensamiento, reflexión, proyecto, expresión dibujada, aplicación constr...

Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography.

Science.gov (United States)

Garcia, Jose Mauricio Botto de Barros; Isaac, David Leonardo Cruvinel; Sardeiro, Tainara; Aquino, Érika; Avila, Marcos

2017-01-01

This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980), an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography

Directory of Open Access Journals (Sweden)

Jose Mauricio Botto de Barros Garcia

Full Text Available ABSTRACT This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980, an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

Monte Carlo simulation of zinc protoporphyrin fluorescence in the retina

Science.gov (United States)

Chen, Xiaoyan; Lane, Stephen

2010-02-01

We have used Monte Carlo simulation of autofluorescence in the retina to determine that noninvasive detection of nutritional iron deficiency is possible. Nutritional iron deficiency (which leads to iron deficiency anemia) affects more than 2 billion people worldwide, and there is an urgent need for a simple, noninvasive diagnostic test. Zinc protoporphyrin (ZPP) is a fluorescent compound that accumulates in red blood cells and is used as a biomarker for nutritional iron deficiency. We developed a computational model of the eye, using parameters that were identified either by literature search, or by direct experimental measurement to test the possibility of detecting ZPP non-invasively in retina. By incorporating fluorescence into Steven Jacques' original code for multi-layered tissue, we performed Monte Carlo simulation of fluorescence in the retina and determined that if the beam is not focused on a blood vessel in a neural retina layer or if part of light is hitting the vessel, ZPP fluorescence will be 10-200 times higher than background lipofuscin fluorescence coming from the retinal pigment epithelium (RPE) layer directly below. In addition we found that if the light can be focused entirely onto a blood vessel in the neural retina layer, the fluorescence signal comes only from ZPP. The fluorescence from layers below in this second situation does not contribute to the signal. Therefore, the possibility that a device could potentially be built and detect ZPP fluorescence in retina looks very promising.

Administración de proyectos con Excel usando PERT/CPM

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Carlos Azofeifa Zamora

2016-03-01

Full Text Available Se presenta la técnica PERT/CPM de la ciencia administrativa, que ayuda a comprobar y controlar aquellos proyectos que involucran muchas tareas interrelacionadas, mediante la resolución de un problema de la administración de proyectos con la ayuda de la hoja electrónica Excel, además, se realiza un análisis de sus beneficios. También se aplica la técnica PERT/Costos en el control de los costos del proyecto, Nassir Sapag Chain (2001 es una guía especial en este tema.

Genetics of lattice degeneration of the retina.

Science.gov (United States)

Murakami, F; Ohba, N

1982-01-01

First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.

Evaluación de la aplicación de la metodología de gestión de proyectos (PMI) en proyectos de almacenamiento de producto (construcción de tanques) y proyectos de construcción civil de la Gerencia de Refinación de EP PETROECUADOR

OpenAIRE

Melena Heredia, Adriana Graciela; Lara Robayo, Franklin Patricio

2016-01-01

La presente investigación está orientada a evaluar la gestión de proyectos de la Gerencia de Refinación de la EP PETROECUADOR, para determinar las causas de las desviaciones que sufren los proyectos en su ciclo de vida respecto a la planificación inicial; lo que ocasiona que los mismos no concluyan en los plazos previstos, cambiando las condiciones iniciales del proyecto respecto al tiempo, alcance y costo estimados. En virtud de la existencia de variaciones de la línea base de sus proyectos,...

Valoración de la gestión de proyectos en empresas de Bogotá: nivel de madurez en gestión de proyectos

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Sigifredo Arce Labrada

2010-08-01

los análisis de: nivel de metodología, nivel de herramientas, nivel de desarrollo de competencias, nivel de metodología de portafolio, programas y nivel de oficina de gestión de proyectos tendremos una idea más clara acerca de la cultura de proyectos de las empresas bogotanas.

Damage and functional recovery of the mouse retina after exposure to genotoxic agents

International Nuclear Information System (INIS)

Vinogradova, Yu.V.; Tronov, V.A.; Lyakhova, K.N.; Ostrovskij, M.A.

2013-01-01

As is known, the mature retina is characterized by high radiation resistance. We showed earlier that ionizing radiation at a dose of ≥25 Gy and the chemical genotoxic agent methylnitrosourea (MNU) in a concentration of ≥60 mg/kg induce acute retinal degeneration, combined with proapoptotic protein expression. The process has a high genotoxic threshold, below which no degeneration signs were traced. The aim of this work was to study the damaging effect of ionizing radiation and MNU on the functional activity of the retina and its ability to recover after exposure to these genotoxicants. The functional activity of the mouse retina was evaluated with electroretinograms (ERG). In parallel, morphological changes in the retina were controlled, and the TUNEL detection of the death of its cell elements was performed. It has been shown that gamma rays or accelerated proton irradiation below 15 Gy cause no structural or functional changes in the mouse retina, which confirms the mature retina's high radiation resistance. Irradiation with a higher dose of 25 Gy leads to photoreceptor layer destruction. This goes along with an increase in the number of the TUNEL-positive photoreceptors, among which are cells with fragmented nuclei, which are typical of apoptosis. MNU in a concentration of 70 mg/kg caused the irreversible loss of the retina's physiological activity, and the morphological degeneration of photoreceptors and their mass death. In a concentration of 35 mg/kg, however, MNU had no cytotoxic effect on the retina. Moreover, this dose caused a reversible ERG amplitude decrease. Also, adaptive response was observed in the retina, which became apparent after two consecutive MNU injections - first, at a dose of 17 mg/kg; then, at a cytotoxic dose of 70 mg/kg. These results point to the possibility of the neurohormesis effect, which was described concerning the retina's exposure to ionizing radiation and some chemicals.

Distribution of tubulin, kinesin, and dynein in light- and dark-adapted octopus retinas.

Science.gov (United States)

Martinez, J M; Elfarissi, H; De Velasco, B; Ochoa, G H; Miller, A M; Clark, Y M; Matsumoto, B; Robles, L J

2000-01-01

Cephalopod retinas exhibit several responses to light and dark adaptation, including rhabdom size changes, photopigment movements, and pigment granule migration. Light- and dark-directed rearrangements of microfilament and microtubule cytoskeletal transport pathways could drive these changes. Recently, we localized actin-binding proteins in light-/dark-adapted octopus rhabdoms and suggested that actin cytoskeletal rearrangements bring about the formation and degradation of rhabdomere microvilli subsets. To determine if the microtubule cytoskeleton and associated motor proteins control the other light/dark changes, we used immunoblotting and immunocytochemical procedures to map the distribution of tubulin, kinesin, and dynein in dorsal and ventral halves of light- and dark-adapted octopus retinas. Immunoblots detected alpha- and beta-tubulin, dynein intermediate chain, and kinesin heavy chain in extracts of whole retinas. Epifluorescence and confocal microscopy showed that the tubulin proteins were distributed throughout the retina with more immunoreactivity in retinas exposed to light. Kinesin localization was heavy in the pigment layer of light- and dark-adapted ventral retinas but was less prominent in the dorsal region. Dynein distribution also varied in dorsal and ventral retinas with more immunoreactivity in light- and dark-adapted ventral retinas and confocal microscopy emphasized the granular nature of this labeling. We suggest that light may regulate the distribution of microtubule cytoskeletal proteins in the octopus retina and that position, dorsal versus ventral, also influences the distribution of motor proteins. The microtubule cytoskeleton is most likely involved in pigment granule migration in the light and dark and with the movement of transport vesicles from the photoreceptor inner segments to the rhabdoms.

Clonal origins of cells in the pigmented retina of the zebrafish eye

International Nuclear Information System (INIS)

Streisinger, G.; Coale, F.; Taggart, C.; Walker, C.; Grunwald, D.J.

1989-01-01

Mosaic analysis has been used to study the clonal basis of the development of the pigmented retina of the zebrafish, Brachydanio rerio. Zebrafish embryos heterozygous for a recessive mutation at the gol-1 locus were exposed to gamma-irradiation at various developmental stages to create mosaic individuals consisting of wild-type pigmented cells and a clone of pigmentless (golden) cells in the eye. The contribution of individual embryonic cells to the pigmented retina was measured and the total number of cells in the embryo that contributed descendants to this tissue was determined. Until the 32-cell stage, almost every blastomere has some descendants that participate in the formation of the pigmented retina of the zebrafish. During subsequent cell divisions, up to the several thousand-cell stage, the number of ancestral cells is constant: approximately 40 cells are present that will give rise to progeny in the pigmented retina. Analysis of the size of clones in the pigmented retina indicates that the cells of this tissue do not arise through a rigid series of cell divisions originating in the early embryo. The findings that each cleavage stage cell contributes to the pigmented retina and yet the contribution of such cells is highly variable are consistent with the interpretation that clonal descendants of different blastomeres normally intermix extensively prior to formation of the pigmented retina

FACTORES DE ÉXITO EN 68 PROYECTOS COLOMBIANOS

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Luz Marina Sanchez Ayala

2014-12-01

Full Text Available Este trabajo analiza las variables que impactan de manera positiva o negativa la gestión de proyectos, a partir de la revisión teórica de los diferentes informes realizados a nivel internacional. Los resultados obtenidos son estudiados por medio de un análisis descriptivo y exploratorio realizado en el contexto de la realidad empresarial colombiana, detallando las causas más frecuentes de éxitos y fracaso en los proyectos. El estudio por medio de información recolectada, indaga en un grupo de empresas como estas variables son manejadas al interior de las organizaciones y cuáles son los mecanismos que han desarrollado para gestionarlas. Con base en las conclusiones obtenidas, se documentan los lineamientos y mecanismos públicos y privados que brindan apoyo sobre las variables transcendentales y así brindar al proceso de gerencia de proyectos herramientas efectivas para la gestión del riesgo en Colombia.

[Lattice degeneration of the peripheral retina: ultrastructural study].

Science.gov (United States)

Bec, P; Malecaze, F; Arne, J L; Mathis, A

1985-01-01

The ultrastructural study of a case of snail track degeneration shows the presence of lipid inclusions in both the glial and the macrophage cells in every layer of the retina, and the existence of intraretinal fibers different from collagen fibers appearing to be glial filaments similar to those found in astrocytic gliomes and to the Rosenthal fibers observed in senile nervous cells. Other features were thinning of the retina and absence of blood vessels in the retina. There are no abnormalities of the vitreo-retinal juncture. All the lesions are in agreement with those observed by Daicker [Ophthalmologica, Basel 165: 360-365, 1972; Klin. Mbl. Augenheilk. 172: 581-583, 1978] with some differences, however. They are different from those found in lattice degeneration. They show that snail track degeneration is a specific form of peripheral retinal degeneration which is quite different from lattice degeneration and must not be considered similar.

Impact of MCT1 Haploinsufficiency on the Mouse Retina

KAUST Repository

Peachey, Neal S.

2018-05-02

The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

Impact of MCT1 Haploinsufficiency on the Mouse Retina

KAUST Repository

Peachey, Neal S.; Yu, Minzhong; Han, John Y. S.; Lengacher, Sylvain; Magistretti, Pierre J.; Pellerin, Luc; Philp, Nancy J.

2018-01-01

The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

Impact of bronchopulmonary dysplasia on brain and retina

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Annie Wing Hoi Poon

2016-04-01

Full Text Available Many premature newborns develop bronchopulmonary dysplasia (BPD, a chronic lung disease resulting from prolonged mechanical ventilation and hyperoxia. BPD survivors typically suffer long-term injuries not only to the lungs, but also to the brain and retina. However, currently it is not clear whether the brain and retinal injuries in these newborns are related only to their prematurity, or also to BPD. We investigated whether the hyperoxia known to cause histologic changes in the lungs similar to BPD in an animal model also causes brain and retinal injuries. Sprague Dawley rat pups were exposed to hyperoxia (95% O2, ‘BPD’ group or room air (21% O2, ‘control’ group from postnatal day 4–14 (P4–14; the rat pups were housed in room air between P14 and P28. At P28, they were sacrificed, and their lungs, brain, and eyes were extracted. Hematoxylin and eosin staining was performed on lung and brain sections; retinas were stained with Toluidine Blue. Hyperoxia exposure resulted in an increased mean linear intercept in the lungs (P<0.0001. This increase was associated with a decrease in some brain structures [especially the whole-brain surface (P=0.02], as well as a decrease in the thickness of the retinal layers [especially the total retina (P=0.0008], compared to the room air control group. In addition, a significant negative relationship was observed between the lung structures and the brain (r=−0.49, P=0.02 and retina (r=−0.70, P=0.0008 structures. In conclusion, hyperoxia exposure impaired lung, brain, and retina structures. More severe lung injuries correlated with more severe brain and retinal injuries. This result suggests that the same animal model of chronic neonatal hyperoxia can be used to simultaneously study lung, brain and retinal injuries related to hyperoxia.

Spontaneous activity in the developing mammalian retina: Form and function

Science.gov (United States)

Butts, Daniel Allison

Spontaneous neuronal activity is present in the immature mammalian retina during the initial stages of visual system development, before the retina is responsive to light. This activity consists of bursts of action potentials fired by retinal ganglion cells, and propagates in a wavelike manner across the inner plexiform layer of the retina. Unlike waves in other neural systems, retinal waves have large variability in both their rate and direction of propagation, and individual waves only propagate across small regions of the retina. The unique properties of retinal activity arise from dynamic processes within the developing retina, and produce characteristic spatiotemporal properties. These spatiotemporal properties are of particular interest, since they are believed to play a role in visual system development. This dissertation addresses the complex spatiotemporal patterning of the retinal waves from two different perspectives. First, it proposes how the immature circuitry of the developing retina generates these patterns of activity. In order to reproduce the distinct spatiotemporal properties observed in experiments, a model of the immature retinal circuitry must meet certain requirements, which are satisfied by a coarse-grained model of the developing retina that we propose. Second, this dissertation addresses how the particular spatiotemporal patterning of the retinal waves provides information to the rest of the visual system and, as a result, can be used to guide visual system development. By measuring the properties of this information, we place constraints on the developmental mechanisms that use this activity, and show how the particular spatiotemporal properties of the retinal waves provide this information. Together, this dissertation demonstrates how the apparent complexity of retinal wave patterning can be understood both through the immature circuitry that generates it, and through the developmental mechanisms that may use it. The first three

Müller glia provide essential tensile strength to the developing retina

Science.gov (United States)

MacDonald, Ryan B.; Randlett, Owen; Oswald, Julia; Yoshimatsu, Takeshi

2015-01-01

To investigate the cellular basis of tissue integrity in a vertebrate central nervous system (CNS) tissue, we eliminated Müller glial cells (MG) from the zebrafish retina. For well over a century, glial cells have been ascribed a mechanical role in the support of neural tissues, yet this idea has not been specifically tested in vivo. We report here that retinas devoid of MG rip apart, a defect known as retinoschisis. Using atomic force microscopy, we show that retinas without MG have decreased resistance to tensile stress and are softer than controls. Laser ablation of MG processes showed that these cells are under tension in the tissue. Thus, we propose that MG act like springs that hold the neural retina together, finally confirming an active mechanical role of glial cells in the CNS. PMID:26416961

Hacia un proyecto de vida a partir del proyecto constructivo

OpenAIRE

Cremaschi, Gustavo; Marsili, Luciana

2014-01-01

La población de las cárceles bonaerenses, hoy es del orden de las 25000 personas. Mayoritariamente está compuesta por jóvenes con escasa instrucción, poca o nula experiencia laboral, muy pobres, con orígenes familiares complejos, y casi sin excepción con proyecciones muy cortoplacistas de su vida. En particular la idea de la libertad, que anima a la totalidad de la población, pocas veces es correspondida con un proyecto tangible y real. En este panorama la idea de conseguir un trabajo digno p...

Proyecto investigador

OpenAIRE

Molina, Marta

2012-01-01

Proyecto investigador sobre el Estudio de componentes de la competencia algebraica que se sustentan en conocimiento de la estructura de la Aritmética y el Álgebra, enmarcado en la línea “Didáctica de la Matemática. Pensamiento Numérico. Enseñanza y Aprendizaje del Álgebra”. Documento elaborado para optar a la plaza de Profesor Titular de Universidad, código 6/1/2012, adscrita al área de Didáctica de la Matemática, Departamento de Didáctica de la Matemática de la Facultad de Ciencias de la Ed...

Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

Directory of Open Access Journals (Sweden)

ROBERTO PAES-DE-CARVALHO

2002-09-01

Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

Identification of endogenous flurophores in the layered retina

Science.gov (United States)

Xu, Gaixia; Chen, Danni; Sun, Yiwen; Qu, Junle; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

2007-05-01

In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment epithelium cells exhibited strong autofluorescence with as emission peak of 600+/-10nm when excited with 860-nm light. The emission peak of photoreceptors was at 652+/-5nm, and the emission peak of retinal vessels layer was weak and at 640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which suggested that there wasn't only one endogenous fluorophores of tissues excited.

Standard anatomical and visual space for the mouse retina: computational reconstruction and transformation of flattened retinae with the Retistruct package.

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David C Sterratt

Full Text Available The concept of topographic mapping is central to the understanding of the visual system at many levels, from the developmental to the computational. It is important to be able to relate different coordinate systems, e.g. maps of the visual field and maps of the retina. Retinal maps are frequently based on flat-mount preparations. These use dissection and relaxing cuts to render the quasi-spherical retina into a 2D preparation. The variable nature of relaxing cuts and associated tears limits quantitative cross-animal comparisons. We present an algorithm, "Retistruct," that reconstructs retinal flat-mounts by mapping them into a standard, spherical retinal space. This is achieved by: stitching the marked-up cuts of the flat-mount outline; dividing the stitched outline into a mesh whose vertices then are mapped onto a curtailed sphere; and finally moving the vertices so as to minimise a physically-inspired deformation energy function. Our validation studies indicate that the algorithm can estimate the position of a point on the intact adult retina to within 8° of arc (3.6% of nasotemporal axis. The coordinates in reconstructed retinae can be transformed to visuotopic coordinates. Retistruct is used to investigate the organisation of the adult mouse visual system. We orient the retina relative to the nictitating membrane and compare this to eye muscle insertions. To align the retinotopic and visuotopic coordinate systems in the mouse, we utilised the geometry of binocular vision. In standard retinal space, the composite decussation line for the uncrossed retinal projection is located 64° away from the retinal pole. Projecting anatomically defined uncrossed retinal projections into visual space gives binocular congruence if the optical axis of the mouse eye is oriented at 64° azimuth and 22° elevation, in concordance with previous results. Moreover, using these coordinates, the dorsoventral boundary for S-opsin expressing cones closely matches

Localization and Developmental Expression Patterns of CSPG in the RCS Rat Retina

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Li-Feng Chen

2011-05-01

Full Text Available Purpose: Investigate changes in chondroitin sulfate proteoglycan (CSPG distribution in Royal College of Surgeons (RCS rat retinae. Could CSPGs distribution act as a physical barrier to transplanted cell migration in degenerating retinae? Methods: CSPG expression was examined in RCS and Long-Evans rat retinae from birth to postnatal day 150 (PND150 using immunofluorescence and western-blots. Results: Both groups showed a rapid rise in CSPG expression on PND14, which peaked on PND21 before declining to lower levels by PND35. CSPG expression had risen again by PND90 and remained elevated for the duration of the study (PND150. However, from PND21, CSPG expression was significantly higher (p ≤ 0.05, n = 5 in Long-Evans rat retinae. CSPG-positive cells were localized in the ganglion cell layer (GCL and the photoreceptor outer segment debris zone (DZ; CSPG expression in the DZ was the main contributor to the higher expression in older animals for both groups. Conclusions: Increased expression of CSPGs in the DZ may act as a physical barrier following retinal cellular transplantation. CSPGs in the GCL is probably related to dendritic changes. CSPG accumulation in the older retinae suggests that aging influences the microenvironment in the retina, which may affect the efficacy of cell transplantation.

Evaluación de impacto aplicada a un proyecto de mercadeo social

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Luisa J. García

2011-06-01

Full Text Available Actualmente existe una nueva estrategia empresarial en donde el sectorprivado voluntariamente está buscando involucrarse en los temas sociales. Esta estrategia se conoce como Mercadeo Social y consiste básicamente en una actividad comercial en la cual la empresa privada y una entidad sin ánimo de lucro se alían para promover una marca, producto o servicio para mutuo beneficio. Un ejemplo de proyecto de Mercadeo Social en Colombia, consiste en una alianza entre una compañía multinacional y la Consejería Presidencial para la Equidad de la Mujer. Este proyecto busca ofrecer el acceso a microcréditos a mujeres cabeza de familia microempresarias con el fin de garantizar su independencia económica y en esta medida, luchar contra una de las principales causas de la violencia familiar contra la mujer. Tanto este proyecto como otros ejemplos de Mercadeo Social, promueven proyectos sociales que tienen un impacto directo sobre la sociedad que implica cambios en el bienestar de uno o varios grupos de la población afectados por estos proyectos. El objetivo de este trabajo es aplicar el Modelo de Emparejamiento de la metodología de Evaluación de Impacto al proyecto anteriormente mencionado, para determinar si el mismo ha tenido un impacto positivo para las mujeres beneficiarias en su nivel de ingresos en comparación con mujeres similares que no han sido beneficiarias del mismo. Se espera corroborar a partir de este ejercicio, que dicho proyecto si ha contribuido al bienestar económico y social de muchas mujeres colombianas a la luz de la teoría económica.

Bcl-2 expression during the development and degeneration of RCS rat retinae.

Science.gov (United States)

Sharma, R K

2001-12-14

In various hereditary retinal degenerations, including that in Royal College of Surgeons (RCS) rats, the photoreceptors ultimately die by apoptosis. Bcl-2 is one of the genes, which regulates apoptosis and is thought to promote survival of cells. This study has investigated the developmental expression of Bcl-2 in RCS rat, which is a well-studied animal model for hereditary retinal degeneration. An antibody against Bcl-2 was used for its immunohistochemical localization in dystrophic RCS rat retinae from postnatal (PN) days 4, 7, 13, 35, 45, 70, 202 and 14 months. Results were compared with Bcl-2 localization in congenic non-dystrophic rats from PN 4, 7, 13, 44, 202 and 14 months. Bcl-2 immunoreactivity in non-dystrophic retinae was already present in PN 4 retinae in the nerve fiber layer (presumably in the endfeet of immature Müller cells) and in the proximal parts of certain radially aligned neuroepithelial cells/immature Müller cell radial processes. With increasing age the immunoreactivity in relatively more mature Müller cell radial processes spread distally towards the outer retina and between PN 13 and 44 it reached the adult distribution. No cell bodies in the ganglion cell layer were found to be immunoreactive. Expression of Bcl-2 immunoreactivity in dystrophic RCS rat retinae closely resembled that of non-dystrophic retinae. No immunoreactivity was seen in photoreceptors or retinal pigment epithelium in dystrophic or non-dystrophic retinae. In conclusion, Bcl-2 expression is not altered, either in terms of its chronology or the cell type expressing it, during retinal degeneration in RCS rats.

Progranulin regulates neurogenesis in the developing vertebrate retina.

Science.gov (United States)

Walsh, Caroline E; Hitchcock, Peter F

2017-09-01

We evaluated the expression and function of the microglia-specific growth factor, Progranulin-a (Pgrn-a) during developmental neurogenesis in the embryonic retina of zebrafish. At 24 hpf pgrn-a is expressed throughout the forebrain, but by 48 hpf pgrn-a is exclusively expressed by microglia and/or microglial precursors within the brain and retina. Knockdown of Pgrn-a does not alter the onset of neurogenic programs or increase cell death, however, in its absence, neurogenesis is significantly delayed-retinal progenitors fail to exit the cell cycle at the appropriate developmental time and postmitotic cells do not acquire markers of terminal differentiation, and microglial precursors do not colonize the retina. Given the link between Progranulin and cell cycle regulation in peripheral tissues and transformed cells, we analyzed cell cycle kinetics among retinal progenitors following Pgrn-a knockdown. Depleting Pgrn-a results in a significant lengthening of the cell cycle. These data suggest that Pgrn-a plays a dual role during nervous system development by governing the rate at which progenitors progress through the cell cycle and attracting microglial progenitors into the embryonic brain and retina. Collectively, these data show that Pgrn-a governs neurogenesis by regulating cell cycle kinetics and the transition from proliferation to cell cycle exit and differentiation. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 77: 1114-1129, 2017. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.

Protein changes in the retina following experimental retinal detachment in rabbits

DEFF Research Database (Denmark)

Mandal, Nakul; Lewis, Geoffrey P.; Fisher, Steven K.

2011-01-01

Retinal detachment leads to the widespread cellular remodeling of the retina. The purpose of this study was to identify protein changes that accompany these cellular alterations by comparing the proteomic profiles of sham and experimentally detached rabbit retina. Elucidation of the proteins most...

Experiences of success in industrial plants projects Experiencias exitosas en proyectos de plantas industriales

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Nuria Forcada

2008-08-01

Full Text Available Success has always been the ultimate goal of construction projects, and different researchers have tried to evaluate it using different factors. Although specialized industrial construction usually involves very large scale projects with a high degree of technological complexity, research has mostly focused on civil and residential success factors. Experiences in Industrial Plants projects can help to improve project management and productivity in such a specialized sector. In this kind of projects, the contractual arrangement is one of the core differences on Project management and thus project success. This research seeks to develop a schema for classifying critical success factors as well as a methodology for evaluating projects. This methodology was adopted to evaluate critical success factors in Industrial Plants projects with different contractual arrangements. Findings suggest that although the construction stage has been the focus of many studies, the first stages are decisive for the success of projects; contract construction projects consider project planning to be more important; lump sum contract construction projects give greater importance to monitoring the benefits; bidding competition projects consider the available technology with greater rigor, etc. The results indicate that different Industrial Plants projects involve different success factors and management characteristics to achieve project objectives.En cualquier proyecto de construcción el principal objetivo es que sea exitoso y por lo tanto a lo largo del tiempo diferentes investigadores han tratado de evaluar los factores que influyen en el éxito de proyectos. En el ámbito de la construcción estas investigaciones se han enfocado principalmente a obras civiles y residenciales. Este artículo muestra resultados que provienen de proyectos de construcción industrial especializada que incluyen proyectos de gran escala con un alto grado de complejidad tecnol

Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas.

Science.gov (United States)

Chintalapudi, Sumana R; Wang, XiaoFei; Li, Huiling; Lau, Yin H Chan; Williams, Robert W; Jablonski, Monica M

2016-01-01

Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans -acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5 , expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5-immunopositive cones were

Proyecto Leer Bulletin Number 6.

Science.gov (United States)

Tome, Martha V., Ed.

This annotated, cumulative bibliography, developed by the Proyecto Leer Program, of more than 600 selected works in Spanish focuses on works which meet the following criteria: (1) reading difficulty does not exceed 10th grade level, and (2) selections are suitable for a Spanish-American community. Books for children are listed separately from…

EVALUATION OF INHOMOGENEITIES IN HISTOLOGICAL STRUCTURES (CARTILAGE, RETINA

Directory of Open Access Journals (Sweden)

Lutz Muche

2011-05-01

Full Text Available This paper investigates histological tissues by means of image analysis and spatial statistics. For the quantification of cell frequencies and accumulations two statistical characteristics, intensity function and cluster density, are suggested. The samples are histological sections of human articular cartilage and human retina considered in view of changes during the ageing process. The articular cartilage is characterized by continuous changes of both functions, the cell intensity as well as the clusterization. In contrast, the retina is a trilaminar structure formed in the early embryonic stage without changes by ageing.

Ambientes de aprendizaje y proyectos escolares con la comunidad

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Pablo Carranza

2017-01-01

Full Text Available La investigación propende a contribuir con posibilidades de trabajo de una matemática escolar que trascienda los compartimentos estancos de contenidos, las formas mecanizadas de aprehensión y las desvinculaciones con el contexto socio-cultural de los estudiantes. Sienta sus bases en los fundamentos de la Educación Matemática Crítica, particularmente en lo que concierne a ambientes de aprendizaje. El interés está puesto en explorar las potencialidades de proyectos interdisciplinarios como generadores de sentido para los conocimientos escolares. En este caso esto se realiza en el marco de acciones que vinculan a la universidad con la comunidad. En particular, a través de la elaboración de un molino para una pobladora rural (proyecto concluido así como de un secadero solar para una escuela rural (proyecto en ejecución, estando involucrados estudiantes de niveles no universitarios (terciario en el primer caso y secundario en el segundo en ambas acciones. Entre las principales contribuciones de este tipo de trabajo se resalta la “resignificación” de los aprendizajes escolares y del propio sistema escolar por parte de todos los miembros de la comunidad educativa. También se procura identificar fortalezas y debilidades de la experiencia a efectos de elaborar lineamientos para futuros proyectos interdisciplinarios.

Pannexin1 in the outer retina of the zebrafish, Danio rerio

NARCIS (Netherlands)

Prochnow, N.; Hoffmann, S.; Vroman, R.; Klooster, J.; Bunse, S.; Kamermans, M.; Dermietzel, R.; Zoidl, G.

2009-01-01

In the retina, chemical and electrical synapses couple neurons into functional networks. New candidates encoding for electrical synapse proteins have recently emerged. In the present study, we determined the localization of the candidate protein pannexin1 (zfPanx1) in the zebrafish retina and

La planeación en los Proyectos de Inversión Privada

Directory of Open Access Journals (Sweden)

Henry Carmona Vélez

1988-04-01

Full Text Available Normalmente, los proyectos que se piensan, planifican y realizan pretenden cumplir con el objetivo de satisfacer las necesidades del hombre. En este orden de ideas, el pretender cumplir contiene implícitamente la incertidumbre de fallar o tener éxito. Son muchos los proyectos que, en su vida, se formula o propone el hombre v, gr. Proyectos de estudio, de viajes, de matrimonios, de inversiones de capital, y, por qué no decirlo, de envejecer. Dentro del proceso de formularse proyectos el hombre también ha recurrido al objetivo de proponerse metas y para ello, como es lógico, ha adoptado consciente o inconscientemente, el proceso de pensar, anticipadamente, sobre cómo actuar  y los posibles resultados. Esto no es otra cosa que parte del proceso de la planeación, a grandes rasgos.

Optic nerve signals in a neuromorphic chip I: Outer and inner retina models.

Science.gov (United States)

Zaghloul, Kareem A; Boahen, Kwabena

2004-04-01

We present a novel model for the mammalian retina and analyze its behavior. Our outer retina model performs bandpass spatiotemporal filtering. It is comprised of two reciprocally connected resistive grids that model the cone and horizontal cell syncytia. We show analytically that its sensitivity is proportional to the space-constant-ratio of the two grids while its half-max response is set by the local average intensity. Thus, this outer retina model realizes luminance adaptation. Our inner retina model performs high-pass temporal filtering. It features slow negative feedback whose strength is modulated by a locally computed measure of temporal contrast, modeling two kinds of amacrine cells, one narrow-field, the other wide-field. We show analytically that, when the input is spectrally pure, the corner-frequency tracks the input frequency. But when the input is broadband, the corner frequency is proportional to contrast. Thus, this inner retina model realizes temporal frequency adaptation as well as contrast gain control. We present CMOS circuit designs for our retina model in this paper as well. Experimental measurements from the fabricated chip, and validation of our analytical results, are presented in the companion paper [Zaghloul and Boahen (2004)].

relaPro : Base de datos para encontrar relaciones entre proyectos

OpenAIRE

Fortis Urbano, Julio

2015-01-01

Desarrollo de una base de datos para almacenar proyectos y una aplicación web de ejemplo que permite encontrar elementos comunes entre los proyectos almacenados en el sistema. Desenvolupament d'una base de dades per emmagatzemar projectes i una aplicació web d'exemple que permet trobar elements comuns entre els projectes emmagatzemats en el sistema. Bachelor thesis for the Computer Science program on Databases.

¿Cómo hacer un proyecto de tesis doctoral en Ciencias Sociales?

Directory of Open Access Journals (Sweden)

Martín Retamozo

2014-01-01

Full Text Available La elaboración de proyectos de tesis de posgrado se ha constituido en una instancia relevante en el desarrollo de las investigaciones y la formación en ciencias sociales. Con el objetivo de ser de utilidad a los estudiantes y los docentes en la construcción de los proyectos de tesis, este artículo reflexiona a acerca del lugar del proyecto en la investigación y las distintas dimensiones que éste adquiere como género literario académico.

Proyecto integral de urbanización con viviendas sostenibles en Barranquilla, Colombia

OpenAIRE

Archbold Monterrosa, Carlos Andres; Villadiego Carcamo, Luis Alberto

2012-01-01

Mediante el siguiente documento se busca demostrar una alternativa diferente para el sector de la construcción en la ciudad de Barranquilla – Colombia, a través de un proyecto integral de urbanización con viviendas sostenibles basado a partir de la modificación de un proyecto de urbanismo residencial convencional. En él se expondrá los aspectos importantes que se debe tener en cuenta para la concepción de un proyecto de urbanización sostenible, teniendo como base temas legislativos, financier...

Thyroid Hormone Signaling in the Mouse Retina.

Directory of Open Access Journals (Sweden)

Patrick Arbogast

Full Text Available Thyroid hormone is a crucial regulator of gene expression in the developing and adult retina. Here we sought to map sites of thyroid hormone signaling at the cellular level using the transgenic FINDT3 reporter mouse model in which neurons express β-galactosidase (β-gal under the control of a hybrid Gal4-TRα receptor when triiodothyronine (T3 and cofactors of thyroid receptor signaling are present. In the adult retina, nearly all neurons of the ganglion cell layer (GCL, ganglion cells and displaced amacrine cells showed strong β-gal labeling. In the inner nuclear layer (INL, a minority of glycineric and GABAergic amacrine cells showed β-gal labeling, whereas the majority of amacrine cells were unlabeled. At the level of amacrine types, β-gal labeling was found in a large proportion of the glycinergic AII amacrines, but only in a small proportion of the cholinergic/GABAergic 'starburst' amacrines. At postnatal day 10, there also was a high density of strongly β-gal-labeled neurons in the GCL, but only few amacrine cells were labeled in the INL. There was no labeling of bipolar cells, horizontal cells and Müller glia cells at both stages. Most surprisingly, the photoreceptor somata in the outer nuclear layer also showed no β-gal label, although thyroid hormone is known to control cone opsin expression. This is the first record of thyroid hormone signaling in the inner retina of an adult mammal. We hypothesize that T3 levels in photoreceptors are below the detection threshold of the reporter system. The topographical distribution of β-gal-positive cells in the GCL follows the overall neuron distribution in that layer, with more T3-signaling cells in the ventral than the dorsal half-retina.

Modeling and Simulation of Microelectrode-Retina Interactions

Energy Technology Data Exchange (ETDEWEB)

Beckerman, M

2002-11-30

The goal of the retinal prosthesis project is the development of an implantable microelectrode array that can be used to supply visually-driven electrical input to cells in the retina, bypassing nonfunctional rod and cone cells, thereby restoring vision to blind individuals. This goal will be achieved through the study of the fundamentals of electrical engineering, vision research, and biomedical engineering with the aim of acquiring the knowledge needed to engineer a high-density microelectrode-tissue hybrid sensor that will restore vision to millions of blind persons. The modeling and simulation task within this project is intended to address the question how best to stimulate, and communicate with, cells in the retina using implanted microelectrodes.

Dinámicas del relacionamiento comunitario de un proyecto minero localizado en el subtrópico ecuatoriano: el caso del proyecto Curipamba.

OpenAIRE

Hidalgo Mantilla, Elbio Ferdinand

2016-01-01

La presente investigación hace referencia a las dinámicas desarrolladas en los procesos de relacionamiento comunitario del proyecto minero Curipamba, el cual se localiza en el subtrópico de la provincia de Bolívar y pertenece a la empresa minera Curimining S.A., dedicada a la exploración geológica de áreas con potencial minero en el Ecuador. El aspecto primordial de la investigación se enfoca en comprender cómo los actores involucrados en dicho proyecto minero llegaron a establecer interaccio...

Direct transdifferentiation in the vertebrate retina.

Science.gov (United States)

Opas, M; Dziak, E

1998-03-01

Transdifferentiation is the process by which differentiated cells alter their identity to become other, distinct cell types. The conversion of neural retina into lens epithelium is one of the most spectacular examples of transdifferentiation. We show that the redirection of cell fate from neural retina to lens and subsequent transdifferentiation is independent of cell replication as it occurs in growth-arrested cell populations. Using DNA ratiometry of individual cells in these cultures we show that, indeed, individual amitotic cells do transdifferentiate. Hence, choice of fate in transdifferentiating cells does not rely on a "community effect" but instead can be categorized as a leadership effect> For lack of overt lens progenitors, and most importantly, for its mitotic independence, we conclude that lens colony formation in vitro does occur by direct transdifferentiation and not by clonal proliferation of progenitor cells.

Distribution of photon absorption rates across the rat retina.

Science.gov (United States)

Williams, T P; Webbers, J P; Giordano, L; Henderson, R P

1998-04-15

1. An investigation into the distribution of light intensity across the rat retina was carried out on excised, intact rat eyes exposed to Ganzfeld illumination from a helium-neon laser (543 nm). 2. Some of the light entering the eyes exits through the sclera where its intensity can be monitored with an optical 'pick-up' that samples the intensity coming from a small region of external sclera and underlying retina. The spatial resolution of the pick-up is such that it samples light that has passed through ca 2 % of the rods in the rat eye. 3. Some of the laser light is absorbed by the rod pigment, rhodopsin, which gradually bleaches. Bleaching in the retina, in turn, causes an exponential increase in intensity emanating from the sclera. By monitoring this intensity increase, we are able to measure two important parameters in a single bleaching run: the local rhodopsin concentration and the local intensity falling on the rods. 4. With an ocular transmission photometer, we have measured both the local intensity and the local rhodopsin concentration across wide regions of rat retina. Both pigmented and albino rats were studied. 5. The distributions of rhodopsin and intensity were both nearly uniform; consequently, the product, (rhodopsin concentration) x (intensity), was similarly nearly equal across the retina. This means that the initial rate of photon absorption is about the same at all retinal locations. 6. Interpreted in terms of photostasis (the regulation of daily photon catch), this means that the rate of photon absorption is about the same in each rod, viz. 14 400 photons absorbed per rod per second. Since this rate of absorption is sufficient to saturate the rod, one possible purpose of photostasis is to maintain the rod system in a saturated state during daylight hours.

Análisis de una empresa del sector turístico Restaurante El Olivar

Directory of Open Access Journals (Sweden)

Daniel Francisco Calderón Cifuentes

2013-11-01

Full Text Available En la Facultad de Administración de Empresas Turísticas y Hoteleras de la Universidad Externado de Colombia, se realiza un proyecto integrador de todos los espacios académicos competentes en la Facultad. El objetivo principal del proyecto varía cada semestre y en este caso tiene el fin de analizar una empresa del sector turístico, desde su organización y funcionamiento. En esta ocasión la organización con enfoque administrativo seleccionada para el desarrollo del proyecto fue el Restaurante El Olivar. Los resultados obtenidos han sido plenamente satisfactorios, demostrando las características que necesita una organización para ser exitosa y los requerimientos indispensables para llegar a ser un excelente administrador. Así mismo, se logró tener un acercamiento al funcionamiento de la industria turística y comercial de Bogotá.

Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas

Science.gov (United States)

Chintalapudi, Sumana R.; Wang, XiaoFei; Li, Huiling; Lau, Yin H. Chan; Williams, Robert W.; Jablonski, Monica M.

2016-01-01

Purpose Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Methods Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. Results In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans-acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5, expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5

Nutritional manipulation of primate retinas, III: Effects of lutein or zeaxanthin supplementation on adipose tissue and retina of xanthophyll-free monkeys.

Science.gov (United States)

Johnson, Elizabeth J; Neuringer, Martha; Russell, Robert M; Schalch, Wolfgang; Snodderly, D Max

2005-02-01

Macular pigment (MP) is composed of the xanthophylls lutein (L) and zeaxanthin (Z) and may help to prevent age-related macular degeneration or retard its progression. In this study the effects of L or Z supplementation on carotenoid levels was examined in serum, adipose tissue, and retina in rhesus monkeys with no previous intake of xanthophylls. From birth to 7 to 16 years of age, 18 rhesus monkeys were fed semipurified diets containing all essential nutrients but no xanthophylls. Six were supplemented with pure L and 6 with pure Z at 3.9 micromol/kg per day for 24 to 101 weeks. At baseline and at 4- to 12-week intervals, carotenoids in adipose tissue were measured by HPLC. At study completion, carotenoids in serum and retina (central 4 mm, 8-mm annulus, and the periphery) were determined. Results were compared with data from control monkeys fed a standard laboratory diet. Monkeys fed xanthophyll-free diets had no L or Z in serum or tissues. After L or Z supplementation, serum and adipose tissue concentrations significantly increased in the supplemented groups. Both L and 3R,3'S-Z (RSZ or meso-Z, not present in the diet) were incorporated into retinas of monkeys supplemented with L, with RSZ present only in the macula (central 4 mm). All-trans Z, but no RSZ, accumulated in retinas of monkeys supplemented with Z. L is the precursor of RSZ, a major component of macular pigment. Xanthophyll-free monkeys can accumulate retinal xanthophylls and provide a valuable model for examining their uptake and conversion.

Frequency of Toxoplasma gondii in the retina in eye banks in Brazil.

Science.gov (United States)

Costa, Deise F; Nascimento, Heloisa; Sutili, Aline; Nobrega, Fernando A J; Fowler, Flavio; Nobrega, Mario Junqueira; Garrido, Cristina; de Oliveira Dias, Janaina; Adán, Consuelo B D; Rizzo, Luiz Vicente; Silveira, Claudio; Belfort, Rubens; Commodaro, Alessandra G

2017-07-01

Ocular toxoplasmosis is the main cause of posterior uveitis worldwide frequently leading to vision loss. In Brazil, the seroprevalence of Toxoplasma gondii infection ranges from 50 to 80% depending of the region studied. The frequency of toxoplasmic retinal scar may reach 18% of the adults in the South of Brazil. Our goal was to determine the frequency of T. gondii DNA in retinas from eye banks from different regions in Brazil. A total of 162 eyes were obtained from eye banks in Manaus (n = 60), Sao Paulo (n = 60), Chapeco (n = 26), and Joinville (n = 16). The retinas were macroscopically analyzed and collected for DNA extraction. Real-time PCR (qPCR) was performed using the T. gondii B1 marker. By qPCR, a higher frequency of T. gondii DNA in the retinas from the eye bank of Joinville (25%) was found when compared to Manaus (5%). The retinas from Sao Paulo and Chapeco were qPCR negative. Clinical examination determined the retina lesions to be compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), Sao Paulo (6.7%), and Chapeco (15.4%).

P+C : Proyecto y Ciudad : revista de temas de arquitectura. Número 2

OpenAIRE

Universidad Politécnica de Cartagena

2011-01-01

«Proyecto y Ciudad» es una revista científica que publica artículos originales y difunde la intención programática y expresiva del Grupo de Investigación «Cartagena: Proyecto & Ciudad» de la Universidad Politécnica de Cartagena. Está dedicada a la investigación, análisis y crítica sobre temas relacionados con la Arquitectura, entendida ésta como un acto complejo que reúne pensamiento, reflexión, expresión, proyecto, inserción urbana e historia. Va dirigida preferentemente a la comunidad cient...

P+C : Proyecto y Ciudad : revista de temas de arquitectura. Número 3

OpenAIRE

Universidad Politécnica de Cartagena

2012-01-01

«Proyecto y Ciudad» es una revista científica que publica artículos originales y difunde la intención programática y expresiva del Grupo de Investigación «Cartagena: Proyecto & Ciudad» de la Universidad Politécnica de Cartagena. Está dedicada a la investigación, análisis y crítica sobre temas relacionados con la Arquitectura, entendida ésta como un acto complejo que reúne pensamiento, reflexión, expresión, proyecto, inserción urbana e historia. Va dirigida preferentemente a la comunidad cient...

Proyecto comunitario. Comunicándonos hacia el desarrollo

Directory of Open Access Journals (Sweden)

Ana Lorena Malluk Marenco

2009-03-01

Full Text Available El uso de la comunicación en proyectos de desarrollo tiene gran impacto pues es una herramienta primordial de transformación social. La finalidad de este proyecto "AMIGOS DEL PARQUE", de la Facultad de Comunicación Social de la Universidad Pontificia Bolivariana de Montería-Colombia, es involucrar a la comunidad educativa en la investigación, reflexión, discusión y participación de temas y problemáticas coyunturales. La incorporación del uso de la radio más el teatro, el video, el internet fueron importantes para generar los cambios sociales.

Some indications of structural damage in retina by heavy ion radiation

International Nuclear Information System (INIS)

Nelson, A.C.; Hayes, T.L.; Tobias, C.A.; Yang, T.C.

1981-01-01

At the Lawrence Berkeley Laboratory Bevalac Facility, iron nuclei were accelerated to an energy of 600 MeV/amu. The beam of iron thus obtained was used to irradiate living biological specimens in order to study possible microscopic tissue damage with the aid of SEM. The experiments involved total head irradiation of live rats which were subsequently returned to their cages to remain for 1 day and 30 days before further examination. After the 1 day and 30 day waits, both eyes were enucleated and placed in chemical fixative followed by ethanol dehydration and critical point drying. Retinas were carefully removed from the eye cups and loaded separately on aluminum stubs which were sputter coated. SEM of the 1 day and 30 day retinas revealed lesions which were not found at all in control retinas. The 1 day and 30 day retinas manifest regions where outer rod segments were missing or rearranged. A single energetic iron nucleus may be capable of generating a retinal lesion which becomes enlarged as biological processes intervene during the 1 day and 30 day waits. Being composed of highly specialized nerve cells, retinas cannot regenerate following irradiation which severely damages the rod cells. Thus one would expect the observed radiation induced retinal lesions to correspond to permanent tissue damage and possible loss of visual acuity in the intact animal

Insulin-like activity in the retina

International Nuclear Information System (INIS)

Das, A.

1986-01-01

A number of studies have recently demonstrated that insulin or a homologous peptide may be synthesized outside the pancreas also. The present study was designed to investigate whether insulin-like activity exists in the retina, and if it exists, whether it is due to local synthesis of insulin or a similar peptide in the retina. To determine whether the insulin-like immunoreactivity in retinal glial cells is due to binding and uptake or local synthesis of insulin, a combined approach of immunocytochemistry and in situ DNA-RNA hybridization techniques was used on cultured rat retinal glial cells. Insulin-like immunoreactivity was demonstrated in the cytoplasma of these cells. In situ hybridization studies using labeled rat insulin cDNA indicated that these cells contain the mRNA necessary for de novo synthesis of insulin or a closely homologous peptide. Since human retinal cells have, as yet, not been conveniently grown in culture, an ocular tumor cell line, human Y79 retinoblastoma was used as a model to extend these investigations. The presence of insulin-like immunoreactivity as well as insulin-specific mRNA was demonstrated in this cell line. Light microscopic autoradiography following incubation of isolated rat retinal cells with 125 I-insulin showed the presence of insulin binding sites on the photoreceptors and amarcine cells. On the basis of these observations that rat retina glial cells, including Muller cells are sites of synthesis of insulin or a similar peptide, a model for the pathogenesis of dabetic retinopathy is proposed

Rod photoreceptors express GPR55 in the adult vervet monkey retina

DEFF Research Database (Denmark)

Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

2013-01-01

. Yet, its formal classification is still a matter of debate. CB1R and CB2R expression patterns are well described for rodent and monkey retinas. In the monkey retina, CB1R has been localized in its neural (cone photoreceptor, horizontal, bipolar, amacrine and ganglion cells) and CB2R in glial...

Functional and Cellular Responses to Laser Injury in the Rat Snake Retina

National Research Council Canada - National Science Library

Glickman, Randolph D; Elliott, III, W. R; Kumar, Neeru

2007-01-01

.... This animal is of interest for vision research because its eye has an all-cone retina. A linear array of 5 thermal lesions was placed in the retina of anesthetized animals, near the area centralis, using a Nd:VO4 laser (532 nm...

Método para identificar causas de problemas técnicos de proyecto geotécnico

OpenAIRE

Hruškovič, Pavel

2011-01-01

En esta tesis, se estudia con detalle el problema de la identificación de riesgos en los proyectos de construcción, con especial atención en el proyecto geotécnico, entendido en sentido global, como una serie de actividades llevadas a cabo durante las fases de viabilidad, redacción de proyecto, ejecución, explotación, y mantenimiento, cuyo resultado en edificación suele ser una obra de cimentación, mejora del terreno, o contención. Son las fases de viabilidad y redacción de proyecto, en las q...

The Neural Retina in Retinopathy of Prematurity

Science.gov (United States)

Hansen, Ronald M.; Moskowitz, Anne; Akula, James D.; Fulton, Anne B.

2016-01-01

Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP. PMID:27671171

Retina-like sensor image coordinates transformation and display

Science.gov (United States)

Cao, Fengmei; Cao, Nan; Bai, Tingzhu; Song, Shengyu

2015-03-01

For a new kind of retina-like senor camera, the image acquisition, coordinates transformation and interpolation need to be realized. Both of the coordinates transformation and interpolation are computed in polar coordinate due to the sensor's particular pixels distribution. The image interpolation is based on sub-pixel interpolation and its relative weights are got in polar coordinates. The hardware platform is composed of retina-like senor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes the real-time image acquisition, coordinate transformation and interpolation.

A comparison of some organizational characteristics of the mouse central retina and the human macula.

Science.gov (United States)

Volland, Stefanie; Esteve-Rudd, Julian; Hoo, Juyea; Yee, Claudine; Williams, David S

2015-01-01

Mouse models have greatly assisted our understanding of retinal degenerations. However, the mouse retina does not have a macula, leading to the question of whether the mouse is a relevant model for macular degeneration. In the present study, a quantitative comparison between the organization of the central mouse retina and the human macula was made, focusing on some structural characteristics that have been suggested to be important in predisposing the macula to stresses leading to degeneration: photoreceptor density, phagocytic load on the RPE, and the relative thinness of Bruch's membrane. Light and electron microscopy measurements from retinas of two strains of mice, together with published data on human retinas, were used for calculations and subsequent comparisons. As in the human retina, the central region of the mouse retina possesses a higher photoreceptor cell density and a thinner Bruch's membrane than in the periphery; however, the magnitudes of these periphery to center gradients are larger in the human. Of potentially greater relevance is the actual photoreceptor cell density, which is much greater in the mouse central retina than in the human macula, underlying a higher phagocytic load for the mouse RPE. Moreover, at eccentricities that correspond to the peripheral half of the human macula, the rod to cone ratio is similar between mouse and human. Hence, with respect to photoreceptor density and phagocytic load of the RPE, the central mouse retina models at least the more peripheral part of the macula, where macular degeneration is often first evident.

Proyecto de instalación ICT y domotización de vivienda unifamiliar

OpenAIRE

Fusté Gaspar, Meritxell

2008-01-01

Este proyecto pretende dar una idea de la nueva normativa que obliga a crear una infraestructura para facilitar al usuario la llegada de los servicios de telecomunicaciones y para hacer más confortable y segura la vida en una vivienda. El proyecto se divide en dos partes: En la primera parte se encuentra la realización del proyecto de ICT de una vivienda unifamiliar. En la cual se estudian las tecnologías de radiodifusión sonora y recepción de señal de televisión, que hac...

Diagnóstico en la gestión y administración de proyectos para consorcios y coopertivas costarricenses

OpenAIRE

Arce-Sáenz, Carlos; Ramirez-Araya, Ronny

2012-01-01

Proyecto de Graduación (Maestría en Gerencia de Proyectos) Instituto Tecnológico de Costa Rica. Área Académica de Gerencia de Proyectos, 2012. A pesar del gran auge y surgimiento, la administración de proyectos, la mayor parte de la literatura y su aplicabilidad se enfoca hacia sectores de industrias conocidos – tecnologías de información, construcción, ingeniería, gobierno – considerados como tradicionales en gerencia de proyectos. El crecimiento de la gerencia de proyectos se debe a que ...

Cold Shock Proteins Are Expressed in the Retina Following Exposure to Low Temperatures.

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Ignacio M Larrayoz

Full Text Available Hypothermia has been proposed as a therapeutic intervention for some retinal conditions, including ischemic insults. Cold exposure elevates expression of cold-shock proteins (CSP, including RNA-binding motif protein 3 (RBM3 and cold inducible RNA-binding protein (CIRP, but their presence in mammalian retina is so far unknown. Here we show the effects of hypothermia on the expression of these CSPs in retina-derived cell lines and in the retina of newborn and adult rats. Two cell lines of retinal origin, R28 and mRPE, were exposed to 32°C for different time periods and CSP expression was measured by qRT-PCR and Western blotting. Neonatal and adult Sprague-Dawley rats were exposed to a cold environment (8°C and expression of CSPs in their retinas was studied by Western blotting, multiple inmunofluorescence, and confocal microscopy. RBM3 expression was upregulated by cold in both R28 and mRPE cells in a time-dependent fashion. On the other hand, CIRP was upregulated in R28 cells but not in mRPE. In vivo, expression of CSPs was negligible in the retina of newborn and adult rats kept at room temperature (24°C. Exposure to a cold environment elicited a strong expression of both proteins, especially in retinal pigment epithelium cells, photoreceptors, bipolar, amacrine and horizontal cells, Müller cells, and ganglion cells. In conclusion, CSP expression rapidly rises in the mammalian retina following exposure to hypothermia in a cell type-specific pattern. This observation may be at the basis of the molecular mechanism by which hypothermia exerts its therapeutic effects in the retina.

Autofluorescence from the outer retina and subretinal space: hypothesis and review.

Science.gov (United States)

Spaide, Richard

2008-01-01

To review the pathophysiologic principles underlying increased autofluorescence from the outer retina and subretinal space using selected diseases as examples. The ocular imaging information and histopathologic features, when known, were integrated for diseases causing increased autofluorescence from the outer retina and subretinal space. Inferences were taken from this information and used to create a classification scheme. These diseases are principally those that cause separation of the outer retina from the retinal pigment epithelium, thereby preventing proper phagocytosis of photoreceptor outer segments. The separation can arise from increased exudation into the subretinal space or inadequate removal of fluid from the subretinal space. Lack of normal outer segment processing initially leads to increased accumulation of outer segments on the outer retina and subretinal space. Over time, this material is visible as an increasingly thick coating on the outer retina, is yellow, and is autofluorescent. Over time, atrophy develops with thinning of the deposited material and decreasing autofluorescence. The accumulated material is ultimately capable of inducing damage to the retinal pigment epithelium. Diseases causing accumulation of the material include central serous chorioretinopathy, vitelliform macular dystrophy, acute exudative polymorphous vitelliform maculopathy, choroidal tumors, and vitreomacular traction syndrome. The physical separation of the retinal outer segments from the retinal pigment epithelium hinders proper phagocytosis of the outer segments. Accumulation of the shed but not phagocytized outer segments plays a role in disease manifestations for a number of macular diseases.

Proyecto y filosofía (A propósito del proyecto filosófico de Foucault

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Juan Manuel NAVARRO CORDÓN

2009-12-01

Full Text Available RESUMEN: Considerando que la -idea de proyecto» -tal como se deduce de la modernidad y de la filosofía actual- ha conducido a una concepción del hombre como producción de sí, cabe recapitular la crítica de Foucault al somnoliento proyecto antropológico moderno, describiendo su planteamiento (filosofía como arqueología, diagnóstico y refutación como filosofía crítica de la ciencia o de las condiciones en las que el hombre problematiza su entorno y su ser.ABSTRACT: If we consider that the «idea of project» -as deduced from modernity and current philosophy- has led to a conception of the human being as self-production, then it is possible to summarize Foucault's critics to the induced sleepy modern anthropological project by describing its exposition (philosophy as archaeology, diagnosis and rebuttal as a philosophy that criticizes science and the conditions in which man attempts to examine the world-around and his being.

El proyecto "campana educativa para incrementar el consumo de frijoles"

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Ligia Rodr\\u00EDguez

2004-01-01

Full Text Available El proyecto “Campaña educativa para incrementar el consumo de frijoles”. Se describen las diferentes etapas que se siguen en el desarrollo de un proyecto denominado “Campaña educativa para incrementar el consumo de frijoles”. La Campaña tuvo como objetivo “incrementar el consumo de frijoles en la población urbana de clase media de Costa Rica” y contribuir a contrarrestar la disminución en el consumo de este alimento, que se ha presentado en forma muy marcada en el área urbana. El artículo pretende ofrecer una visión global del mencionado proyecto, de manera que le permita al lector la ubicación dentro del proceso, al mismo tiempo que lo refiere a los artículos específicos que ofrecen el detalle de las diferentes etapas y resultados. La metodología describe las características generales del abordaje que se utiliza y la forma en que se desarrolla cada una de las etapas. Los resultados sumarizan los hallazgos de la evaluación y otros aspectos globales del proyecto. Además, ofrece pautas para un abordaje de la educación nutricional focalizada alrededor de un alimento y sustentada en la realidad social y cultural de la población.

Diseño Oficina de Proyectos (PMO) más adecuada para INVERCONST S.A.S.

OpenAIRE

Vargas López, Oscar Fabián

2016-01-01

El presente documento contiene el diseño de una oficina de proyectos tipo básica para la empresa Inverconst S. A. S., como respuesta a la necesidad que tiene la empresa de articular sus proyectos con la estrategia organizacional, a través de proyectos administrados y gestionados de manera ordenada, con procesos de gestión repetibles y estandarizados, facilitando compartir recursos, metodologías, herramientas y técnicas en pro de proyectos exitosos -- El anterior propósito no implica una ofici...

Metodología para especificación de requisitos en proyectos de explotación de información

OpenAIRE

Pollo Cattaneo, María Florencia; Britos, Paola Verónica; Pesado, Patricia Mabel; García Martínez, Ramón

2009-01-01

Este proyecto tiene como objetivo general definir una metodología de educción de requisitos para proyectos de explotación de información que permita ser integral al ciclo de vida de este tipo de proyectos. Se considera que el proyecto implica investigación básica en la definición del proceso de educción de requisitos de este tipo de proyectos.

Complement anaphylatoxin C3a is a potent inducer of embryonic chick retina regeneration

Science.gov (United States)

Haynes, Tracy; Luz-Madrigal, Agustin; Reis, Edimara S.; Echeverri Ruiz, Nancy P.; Grajales-Esquivel, Erika; Tzekou, Apostolia; Tsonis, Panagiotis A.; Lambris, John D.; Del Rio-Tsonis, Katia

2013-01-01

Identifying the initiation signals for tissue regeneration in vertebrates is one of the major challenges in regenerative biology. Much of the research thus far has indicated that certain growth factors have key roles. Here we show that complement fragment C3a is sufficient to induce complete regeneration of the embryonic chick retina from stem/progenitor cells present in the eye, independent of fibroblast growth factor receptor signaling. Instead, C3a induces retina regeneration via STAT3 activation, which in turn activates the injury- and inflammation-responsive factors, IL-6, IL-8 and TNF-α. This activation sets forth regulation of Wnt2b, Six3 and Sox2, genes associated with retina stem and progenitor cells. Thus, our results establish a mechanism for retina regeneration based on injury and inflammation signals. Furthermore, our results indicate a unique function for complement anaphylatoxins that implicate these molecules in the induction and complete regeneration of the retina, opening new avenues of experimentation in the field. PMID:23942241

DIRECTORES DE PROYECTOS DE I+D+I: COMPETENCIAS Y DESAFÍOS

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Marinka Varas Parra

2014-12-01

Full Text Available Para que un proyecto seas terminado con éxito, la planificación y la ejecución deben ser realizadas correctamente. Una mala ejecución no permite lograr la trazabilidad y el aprendizaje de lecciones al equipo de investigación. Este estudio identifica las practicas de gestión de proyectos de I+D+i desde la perspectiva de la calidad, para ello se identificaron cuatro normativas de buenas prácticas aplicables a proyectos de investigación. Luego fueron encuestados 934 directores de grupos de investigación de 20 universidades españolas. Los resultados del estudio revelan que la calidad, el riesgo y el compromiso o apoyo de la universidad son los procesos peor evaluados por los investigadores españoles.

Aplicación Gestión Proyectos Informáticos

OpenAIRE

Navarro Torren, Carlos

2011-01-01

El proyecto a desarrollar consiste en una herramienta para la gestión de proyectos informáticos, cuyo principal objetivo es facilitar el seguimiento y control de las distintas fases por el grupo de trabajo involucrado. Esta herramienta permitirá que los diferentes miembros del equipo de trabajo puedan acceder y gestionar de forma ágil el conjunto de tareas, documentos y otra información asignada, a la vez que la comparten con los demás miembros.

Gestión de riesgos en proyectos: aplicación a campaña batimétrica.

OpenAIRE

Sánchez Pacheco, Lorenzo

2014-01-01

El objetivo global de este proyecto es el estudio del análisis de los riesgos en proyectos. Los temas a tratar serán los siguientes: • Estudiar los métodos y las herramientas de la gestión de análisis de los riesgos en proyectos. • Creación de un proyecto tipo para su posterior aplicación de los procesos de análisis de riesgos, en concreto un proyecto tipo de características sensibles y en nuestro caso una campaña batimétrica. • Diseño de una planificación adecuada y sin inconsistenc...

Análisis de las estrategias de diseminación de resultados de proyectos de investigación e innovación en didáctica de las ciencias : el proyecto Desire

OpenAIRE

Hernández Rodríguez, María Isabel

2013-01-01

En este estudio presentamos un análisis de las estrategias de diseminación de resultados utilizadas en proyectos financiados de didáctica de las ciencias con el fin de identificar las dificultades y necesidades de los diversos agentes implicados: coordinadores de proyectos o investigadores, profesores de ciencias de secundaria, diseñadores de políticas educativas, gestores de proyectos en museos de ciencia y organizadores de eventos de divulgación científica. Con tal objetivo, se diseñaron do...

Proyectos recientes: complejo turístico y residencial de Pingueral

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Roberto Lira Olmo

1997-08-01

Full Text Available Ubicada en el fundo Pingueral, camino a Menque (Comuna de Tomé se encuentra este proyecto de loteo de 150 hectáreas a cargo de la Inmobiliaria Delta Pingueral Ltda. El proyecto incluye 500 lotes, un Club House (750 metros cuadrados construidos más terrazas, una capilla, un anfiteatro para eventos musicales (cap. para 1.000 personas, 5 piscinas de adultos, 3 piscinas de niños, 2 canchas de tenis, 2 canchas de fulbolito, una cancha ecuestre y caballerizas, dos áreas de camping, un snack playero, dos áreas de juegos infantiles, miradores y senderos peatonales, una laguna de río equipada, y áreas verdes en plazoletas. Hasta el momento existen 215 casas construidas con una altura máxima de dos pisos y un proyecto de edificación en altura correspondiente a 5 unidades de departamentos de 90, 110 y 150 metros cuadrados.

"Proyecto Sherezade": Teaching Spanish Literature Interactively.

Science.gov (United States)

Fernandez, Enrique

2001-01-01

Describes "Proyecto Sherezade," an Internet-based project publicly available to anyone. Founded in 1996 by a group of Spanish language and literature academics in Canada and the United States, the project began as an Internet literary magazine that published non-established writers's short stories in Spanish and commentaries sent by readers.…

Training and professional profile of retinologists in Spain: Retina 2 project, Report 4.

Science.gov (United States)

Pastor, J Carlos; Fernández, Itziar; Rojas, Jimena; Coco, Rosa; Sanabria, Maria R; Rodríguez-de la Rúa, Enrique; Sánchez, Diego; Valverde, Carmen; Sala-Puigdollers, Anna

2011-01-01

Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties. After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined. Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%). Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5%) practiced anterior segment surgery, and 78.7% declared skills in vitrectomy. We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.

Gestión de proyecto participativo de centro comunitario intercultural

OpenAIRE

Doble Vía

2012-01-01

La iniciativa, dirigida por la Arq. Karina Cortina, surge como una continuidad del Proyecto “Barrio Intercultural – Lote 27”, en las tierras restituidas en la región de San Martín de los Andes. En esta etapa, el proyecto se centra en la construcción compartida del Centro Comunitario Intercultural, que se construirá con tecnologías apropiadas y sustentables para dicha región. (Párrafo extraído del texto a modo de resumen) Facultad de Arquitectura y Urbanismo

Foreign fighters en ISIS : un acercamiento a las causas del radicalismo Yihadista occidental. Estudio de caso: Francia (2013-2015)

OpenAIRE

Vidal Redondo, Jaime Andres

2016-01-01

El presente documento aborda el debate que se ha generado en diversos escenarios internacionales y particularmente en Francia con relación a la radicalización yihadista de jóvenes franceses y los atentados llevados a cabo al semanario Charlie Hebdo y el Teatro Bataclán en el año 2015. El objetivo es ofrecer un acercamiento a cómo la marginalización y las condiciones socioeconómicas de los musulmanes franceses de segunda y tercera generación contribuyen a procesos de radicalización yihadista y...

Image Signal Transfer Method in Artificial Retina using Laser

Energy Technology Data Exchange (ETDEWEB)

Yoon, I.Y.; Lee, B.H.; Kim, S.J. [Seoul National University, Seoul (Korea)

2002-05-01

Recently, the research on artificial retina for the blind is active. In this paper a new optical link method for the retinal prosthesis is proposed. Laser diode system was chosen to transfer image into the eye in this project and the new optical system was designed and evaluated. The use of laser diode array in artificial retina system makes system simple for lack of signal processing part inside of the eyeball. Designed optical system is enough to focus laser diode array on photodiode array in 20X20 application. (author). 11 refs., 7 figs., 2 tabs.

Clasificación de los proyectos informáticos y establecimiento de sus EDT's

OpenAIRE

Huerta de la Morena, Beatriz

2014-01-01

El objetivo principal del presente proyecto es plasmar una clasificación de los diferentes tipos de proyectos informáticos existentes hoy en día. Presentamos una clasificación basada en algunos criterios diferenciadores para finalmente seleccionar una tipología de proyectos informáticos fuertemente diferenciados entre sí. Posteriormente analizaremos de forma exhaustiva las diferentes etapas y fases de las que se componen, con el fin de conocer las diferentes técnicas de trabajo para la correc...

Consideraciones teórico-prácticas Sobre un proyecto de aula: Un ejemplo desde el lenguaje

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JOSELYN CORREDOR TAPIAS

2007-01-01

Full Text Available En Este artículo se presentan, en principio, algunos planteamientos conceptuales sobre el proyecto de aula – enmarcado en la denominada “pedagogía por proyectos. Posteriormente, se proponen “nuevas definiciones” del proyecto de aula, considerándolo como práctica educativa; enseguida, se dan a conocer y se explican en forma precisa y sucinta las funciones y los elementos básicos de este tipo de proyecto pedagógico; aquí, se hace énfasis en la etapa de la elección y delimitación del tema; la formulación problemática, uno de los momentos cumbres del proyecto de aula. Finalmente, estas urdimbres teóricas se materializan en un caso ejemplificador: un proyecto de aula en el marco del léxico infantil, en donde se puede observar como: Proyecto de aula –interés investigativo- ortografía y léxico infantil constituyen un colectivo dinámico, impulsor e inquietante para producir un breve -pero necesario e interesante intento de diccionario infantil de los niños de 5o. Grado.

Tres experimentos Modernos. El proceso de proyecto del edificio Positano

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Juan Pablo Tuja

2017-04-01

Full Text Available El edificio Positano, proyectado durante la década de 1950 por el arquitecto Luis García Pardo, marca un hito en la arquitectura de la vivienda colectiva moderna en el Uruguay. Para concretar este edificio, el arquitecto -y promotor inmobiliario a la vez- desarrolló una serie de proyectos, identificándose tres proyectos completamente documentados. Esta serie posee un fuerte carácter moderno y experimental, el cual se expresa en la volumetría general, la implantación, en el desarrollo tipológico, el diseño estructural y el diseño de los cerramiento exteriores. El último proyecto, realizado en asociación con el joven arquitecto Adolfo Sommer Smith, comienza a construirse en 1959. La serie de proyectos, evidencia un creciente proceso de “abstracción”, tanto formal como conceptual. Lo cual conducirá por un lado a simplificar formas y reducir elementos, y por otro a diseñar dispositivos de mayor complejidad, capaces de resolver funciones diversas al mismo tiempo. A partir de la búsqueda y clasificación de documentación de época –planos, fotografías, artículos, entre otros–, el presente trabajo intentó ensayar una interpretación proyectual, exponiendo las principales preocupaciones y estrategias de los arquitectos. El ensayo buscó reconocer repeticiones, iteraciones, dudas y certezas de un proceso proyectual intenso, que transitó los bordes de la disciplina.

HB-EGF is necessary and sufficient for Müller glia dedifferentiation and retina regeneration

Science.gov (United States)

Wan, Jin; Ramachandran, Rajesh; Goldman, Daniel

2011-01-01

Summary Müller glia (MG) dedifferentiation into a cycling population of multipotent progenitors is crucial to zebrafish retina regeneration. The mechanisms underlying MG dedifferentiation are unknown. Here we report that heparin-binding epidermal-like growth factor (HB-EGF) is rapidly induced in MG residing at the injury site and that proHB-EGF ectodomain shedding is necessary for retina regeneration. Remarkably, HB-EGF stimulates the formation of multipotent MG-derived progenitors in the uninjured retina. We show that HB-EGF mediates its effects via an EGFR/MAPK signal transduction cascade that regulates the expression of regeneration-associated genes, like ascl1a and pax6b. We also uncover an HB-EGF/Ascl1a/Notch/hb-egfa signaling loop that helps define the zone of injury-responsive MG. Finally, we show that HB-EGF acts upstream of the Wnt/β-catenin signaling cascade that controls progenitor proliferation. These data provide a link between extracellular signaling and regeneration-associated gene expression in the injured retina and suggest strategies for stimulating retina regeneration in mammals. PMID:22340497

Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

Science.gov (United States)

Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

2015-04-01

For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

Frequency spectrum might act as communication code between retina and visual cortex I.

Science.gov (United States)

Yang, Xu; Gong, Bo; Lu, Jian-Wei

2015-01-01

To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1). Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG) and pattern visually evoked potential (PVEP) and fast Fourier transform has been used to analyze the frequency components of those signals. The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

Proyecto Metrotrén: ¿sueño o realidad?

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Guillermo Besser

1997-08-01

Full Text Available Con ocasión de la reciente entrega del estudio de pre-factibilidad del proyecto de metrotrén intercomunal, de alguna manera se revive la idea, ya casi parte de la memoria colectiva de los "pencopolitanos", de implementar un metrotrén en la intercomuna. A través de la siguiente entrevista a Guillermo Besser, Jefe Regional de Rehabilitación de la Empresa de Ferrocarriles del Estado esperamos entregar una visión más profunda sobre el "origen y destino" de este proyecto.

Estrategias de actuación para un aprendizaje participativo en Proyectos Arquitectónicos

OpenAIRE

Bosch Abarca, Jorge; Perez Rodriguez, Marta

2012-01-01

Comunicación presentada a las Jornadas de Innovación Educativa 2012 de la UPV. Descripción de la acción desarrollada por los profesores de Proyectos 2 del Taller H de la Escuela de Arquitectura de la UPV, dirigida a aumentar la participación del estudiante de Proyectos Arquitectónicos en el proceso de enseñanza-aprendizaje. Bosch Abarca, J.; Perez Rodriguez, M. (2012). Estrategias de actuación para un aprendizaje participativo en Proyectos Arquitectónicos. Editorial Universitat Politècn...

Proyecto ejecutivo (prácticum), seguimiento de obra e interiorismo de un local comercial

OpenAIRE

Huerga López, Sandra

2016-01-01

El proyecto del centro comercial que os presento a continuación es un proyecto real en el cual hay partes que las realicé durante mi convenio universidad-empresa (considerando esta parte como un practicum), otra parte que la realicé solo para el Trabajo Final de Grado y la última parte de documentación aportada por la empresa (El segundo cuaderno). Nos centraremos en las dos primeras partes. Los planos del proyecto ejecutivo los realicé en la empresa con la supervisión del ingeniero....

TOPOGRAPHIC ORGANIZATION AND SPECIALIZED AREAS IN THE RETINA OF Callopistes palluma: GANGLION CELL LAYER

OpenAIRE

Inzunza, Oscar; Barros B., Zitta; Bravo, Hermes

1998-01-01

In this paper we analyze the topographic distribution and cell body size of neurons (ganglion and displaced amacrine) of layer 8 of the retina in the chilean reptile Callopistes palluma; using whole mount retinaswith nissl stain. Callopistes palluma retina has an area centralis without fovea in which the ganglion cell density amounts 20.000 cells / µm2 while the displaced amacrine neurons is about 7.000 cells / µm2. This neural density decreased gradually towards the peripheral retina. A hor...

Investigación sobre acondicionamiento ambiental y sostenibilidad en las prospecciones petrolíferas

OpenAIRE

Serna Murillo, José Antonio

2008-01-01

El proyecto de tesis partió del cuestionamiento de conocer los impactos medioambientales causados por las distintas actividades derivadas de la industria petrolera, siendo que las condicionantes y parámetros que inciden de forma directa en sus actividades son hasta cierto punto difíciles de establecer. Como resultado del primer acercamiento realizado, se descubrió que era necesario el desarrollo de una metodología de control que ayudara a resarcir y/o amortiguar los impactos generados por...

NIÑOS INVULNERABLES. FACTORES COTIDIANOS DE PROTECCIÓN QUE FAVORECEN EL DESARROLLO DE LOS NIÑOS QUE VIVEN EN CONTEXTOS DE POBREZA

OpenAIRE

José Amar Amar

2000-01-01

El proyecto Infancia y Calidad de Vida ha adelantado diversas investigaciones, con el fin de solucionar los problemas que enfrenta la niñez en desventaja que vive en condiciones de pobreza extrema. Las investigaciones buscan un acercamiento y un conocimiento adecuado de la realidad de estos niños en su cotidianeidad, para así identificar aquellos factores que los protegen de la adversidad y que les permiten superarse. Los niños que logran superar la adversidad, las consecuen...

Proyecto Aurora: Building a Community of Women.

Science.gov (United States)

Noya, Gladys R. Capella

1997-01-01

Describes the development of Proyecto Aurora, a program to develop and implement educational, support, and research programs to benefit low-income women in Puerto Rico. Portraits of some clients illustrate the rewards and challenges of working with this community and furthering their educational experiences and opportunities. (SLD)

Frequency spectrum might act as communication code between retina and visual cortex I

Directory of Open Access Journals (Sweden)

Xu Yang

2015-12-01

Full Text Available AIM: To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1. METHODS: Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG and pattern visually evoked potential (PVEP and fast Fourier transform has been used to analyze the frequency components of those signals. RESULTS: The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. CONCLUSION: The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

Towards photovoltaic powered artificial retina

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Santiago Silvestre

2011-11-01

Full Text Available The aim of this article is to provide an overview of current and future concepts in the field of retinal prostheses, and is focused on the power supply based on solar energy conversion; we introduce the possibility of using PV minimodules as power supply for a new concept of retinal prostheses: Photovoltaic Powered Artificial Retina (PVAR. Main characteristics of these PV modules are presented showing its potential for this application.

La elicitación de requisitos en el contexto de un proyecto software

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Markus Manies, Uolevis Nikual

2011-12-01

Full Text Available La Elicitación de Requisitos –ER– es la piedra angular en el desarrollo de proyectos software y tiene un impacto muy alto en el diseño y en las demás fases del ciclo de vida del producto. Si se realiza apropiadamente, puede ayudar a reducir los cambios y las correcciones en los requisitos. Además, la calidad de la elicitación determina la exactitud de la retroalimentación al cliente acerca de la integridad y validez de los requisitos. Debido a que esta fase es crítica y de alto impacto en el proyecto, es muy importante que la labor de elicitar se realice lo más cercano posible a la “perfección”. Teniendo en cuenta las diferentes características de los proyectos software, en este trabajo se proponen algunas reglas generales para llevar a cabo la RE con base en la discusión y en la explicación de los procesos relacionados y métodos aplicados en los diferentes tipos de proyectos software.

La experiencia del proyecto EMILIA en Barcelona. El usuario como experto: concepto, modalidades y experiencia desde el Proyecto Emilia.

OpenAIRE

Paz Flores; Carmen Masferrer; Eithne Leahy; Roser Izquierdo; Eduard Palomer

2010-01-01

Se relata la experiencia del proyecto EMILIA y se ofrece una visión global de qué se entiende por “usuario experto” y “implicación de los usuarios” en salud mental. Se discuten sus implicaciones para los profesionales, usuarios y el sistema sanitario.

Training and professional profile of retinologists in Spain: Retina 2 project, Report 4

Directory of Open Access Journals (Sweden)

Pastor JC

2011-04-01

Full Text Available J Carlos Pastor1,3, Itziar Fernández2, Jimena Rojas1, Rosa Coco1, Maria R Sanabria1, Enrique Rodríguez-de la Rúa1,3, Diego Sánchez3, Carmen Valverde3, Anna Sala Puigdollers1,31University Institute of Applied Ophthalmobiology (IOBA, Retina Group, 2Ministry of Science and Innovation CIBER-BBN, Statistics Department, 3Clinic University Hospital, University of Valladolid, Valladolid, SpainBackground: Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties.Methods: After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined.Results: Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%. Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5% practiced anterior segment surgery, and 78.7% declared skills in vitrectomy.Conclusion: We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.Keywords: clinical activity, fellowship, mastership, professional profile, retinologist training

Análisis de las causas determinantes en el desempeño de los proyectos en Alianza de Servicios Sociales de Caldas

OpenAIRE

Salinas Ávila, Sandra Liliana

2011-01-01

El resultado del presente trabajo de investigación, muestra las causas que determinan el desempeño de los proyectos en Alianza de Servicios Sociales de Caldas, se basa en el análisis de factores como gestión de proyectos, contribución de los proyectos a las organizaciones, los proyectos y la planificación estratégica, gestión estratégica, influencia de la estructura y cultura de la organización en la gestión de proyectos y gerente de proyectos. 117 p. Contenido parcial: Los proyectos en...

Nueva era de CIESPAL: Proyecto CIESPAL-FES

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Fausto Jaramillo

2015-01-01

Full Text Available El artículo presenta una breve descripción del Proyecto -CIESPAL-FES- sus objetivos y un resumen de la investigación que dio lugar al desarrollo del pensum para los becarios que habían de capacitarse en la televisión.

Telemedicina en Bolivia: proyecto RAFT-Altiplano, experiencias, perspectivas y recomendaciones

OpenAIRE

Vargas, Alejandro; Ugalde, Miguel; Vargas, Reynaldo; Narvaez, Ramiro; Geissbuhler, Antoine

2014-01-01

OBJETIVO: El objetivo del proyecto RAFT-Altiplano (RAFT, Red Africana Francófona de Telemedicina) es evaluar la viabilidad, potencialidad y riesgos de la implementación y el desarrollo de una red de telemedicina en el contexto de un país en desarrollo, como es el caso del Altiplano de Bolivia, para mejorar el acceso a la atención médica y la formación continua en el área rural. En este estudio se describe el desarrollo de dicho proyecto entre 2011 y 2013. MÉTODOS: Se donaron equipos de teleme...

El mundo matemático digital: el proyecto WDML (World Digital Mathematics Library

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Macías Virgós, Enrique

2007-06-01

Full Text Available We describe the digitization process of the mathematical literature in the framework of the projects WDML and DML-E.Describimos el proceso de digitalización de la literatura matemática de investigación en el marco del proyecto WDML (World Digital Mathematics Library y del proyecto español DML-E.

Programación reactiva en la administración de proyectos: aproximación conceptual y aplicaciones prácticas

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Alexander Garrido

2013-08-01

Full Text Available Rev.esc.adm.neg La incertidumbre en los proyectos es usualmente un aspecto inevitable. Los gerentes de proyectos se previenen de ella gestionando oportunamente los riesgos conocidos en las fases previas a la ejecución del proyecto. Pese a estos esfuerzos, los riesgos no identificados o incontrolables pueden surgir durante la fase de ejecución del proyecto, lo cual afecta negativamente sus Indicadores Claves de Desempeño (ICD y el objetivo propuesto. Bajo estas circunstancias, el gerente de proyecto es forzado a responder a los riesgos incontrolables o no identificados. Una revisión de la literatura actual sobre administración de proyectos, no proporciona ninguna orientación frente al tema. En este artículo se estudia el enfoque de la programación reactiva a través de un proyecto real, como un modo estructurado de afrontar y medir el efecto de los riesgos incontrolables o no identificados en un proyecto y mantener la consistencia de su línea base.

Estimating large complex projects Estimando proyectos grandes y complejos

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Cliff Schexnayder

2007-08-01

Full Text Available Managing large capital construction projects requires the coordination of a multitude of human, organizational, technical, and natural resources. Quite often, the engineering and construction complexities of such projects are overshadowed by economic, societal, and political challenges. The ramifications and effects, which result from differences between early project cost estimates and the bid price or the final project cost, are significant. Over the time span between the initiation of a project and the completion of construction many factors influence a project's final costs. This time span is normally several years in duration but for highly complex and technologically challenging projects, project duration can easily exceed a decade. Over that period, changes to the project scope often occur. The subject here is a presentation of strategies that support realistic cost estimating. Through literature review and interviews with transportation agencies in the U.S. and internationally the authors developed a database of the factors that are the root causes of cost estimation problemsGestionar proyectos de construcción de grandes capitales requiere de la coordinación de una multitud de recursos humanos, organizacionales, técnicos y naturales. Frecuentemente, las complejidades del diseño y construcción de esos grandes proyectos son tapadas por sus desafíos económicos, políticos y sociales. Las ramificaciones y efectos que resultan de las diferencias entre la estimación de costo inicial, el costo de la propuesta adjudicada y el costo final del proyecto son significativas. Hay numerosos factores que inciden en el costo final del proyecto entre su inicio y finalización. La duración es generalmente de varios años y puede incluso superar la década para aquellos especialmente complejos y desafiantes. En ese período de tiempo, cambios en los alcances del proyecto cambian frecuentemente. El tópico del presente artículo es mostrar

Erythropoetin receptor expression in the human diabetic retina

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Tsang Stephen H

2009-11-01

Full Text Available Abstract Background Recent evidence suggests erythropoietin (EPO and the erythropoietin receptor (EPOR may play a direct role in the pathogenesis of diabetic retinopathy. Better characterization of the EPO-EPOR signaling system in the ischemic retina may offer a new therapeutic modality for ischemic ophthalmic diseases. This study was performed to identify EPOR mRNA expression in the human diabetic eye. Findings EPOR antisense RNA probes were validated on human pancreas tissue. In the normal eye, EPOR was expressed in the retinal ganglion cell layer. Minimal expression was observed in the inner and outer nuclear layer. Under conditions of diabetic retinopathy, EPOR expression shifted to photoreceptor cells. Increased expression was also observed in the peripheral retina. Conclusion EPOR expression may be a biomarker or contribute to disease mechanisms in diabetic retinopathy.

Sobre la terapia génica para enfermedades de la retina.

Science.gov (United States)

Fischer, M Dominik

2017-07-11

Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina. © 2017 S. Karger AG, Basel.

Propuesta de Métricas para Proyectos de Explotación de Información

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Diego Basso

2014-08-01

Full Text Available Los Proyectos de Explotación de Información requieren de un proceso de planificación para estimar el esfuerzo, el tiempo y medir diferentes aspectos del producto para garantizar la calidad del mismo. Los procesos de desarrollo tradicionales y las métricas usuales de la Ingeniería de Software y la Ingeniería del Conocimiento no son adecuados para estos proyectos, ya que las etapas de desarrollo y los parámetros utilizados son de naturaleza y características diferentes. En ese contexto, se ha definido un Modelo de Proceso de Desarrollo para Proyectos Explotación de Información. No obstante, existe la necesidad de abordar métricas específicas aplicables a este proceso. En esta investigación se propone un conjunto de métricas aplicables al desarrollo de un proyecto de Explotación de Información para PyMEs, centrado en el Modelo de Proceso de Desarrollo mencionado.

CLRN1 is nonessential in the mouse retina but is required for cochlear hair cell development.

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Scott F Geller

2009-08-01

Full Text Available Mutations in the CLRN1 gene cause Usher syndrome type 3 (USH3, a human disease characterized by progressive blindness and deafness. Clarin 1, the protein product of CLRN1, is a four-transmembrane protein predicted to be associated with ribbon synapses of photoreceptors and cochlear hair cells, and recently demonstrated to be associated with the cytoskeleton. To study Clrn1, we created a Clrn1 knockout (KO mouse and characterized the histological and functional consequences of Clrn1 deletion in the retina and cochlea. Clrn1 KO mice do not develop a retinal degeneration phenotype, but exhibit progressive loss of sensory hair cells in the cochlea and deterioration of the organ of Corti by 4 months. Hair cell stereocilia in KO animals were longer and disorganized by 4 months, and some Clrn1 KO mice exhibited circling behavior by 5-6 months of age. Clrn1 mRNA expression was localized in the retina using in situ hybridization (ISH, laser capture microdissection (LCM, and RT-PCR. Retinal Clrn1 transcripts were found throughout development and adulthood by RT-PCR, although expression peaked at P7 and declined to undetectable levels in adult retina by ISH. LCM localized Clrn1 transcripts to the retinas inner nuclear layer, and WT levels of retinal Clrn1 expression were observed in photoreceptor-less retinas. Examination of Clrn1 KO mice suggests that CLRN1 is unnecessary in the murine retina but essential for normal cochlear development and function. This may reflect a redundancy in the mouse retina not present in human retina. In contrast to mouse KO models of USH1 and USH2, our data indicate that Clrn1 expression in the retina is restricted to the Müller glia. This is a novel finding, as most retinal degeneration associated proteins are expressed in photoreceptors, not in glia. If CLRN1 expression in humans is comparable to the expression pattern observed in mice, this is the first report of an inner retinal protein that, when mutated, causes retinal

Analysis of MTHFR, CBS, Glutathione, Taurine, and Hydrogen Sulfide Levels in Retinas of Hyperhomocysteinemic Mice.

Science.gov (United States)

Cui, Xuezhi; Navneet, Soumya; Wang, Jing; Roon, Penny; Chen, Wei; Xian, Ming; Smith, Sylvia B

2017-04-01

Hyperhomocysteinemia (Hhcy) is implicated in certain retinal neurovascular diseases, although whether it is causative remains uncertain. In isolated ganglion cells (GCs), mild Hhcy induces profound death, whereas retinal phenotypes in Hhcy mice caused by mutations in remethylation (methylene tetrahydrofolatereductase [Mthfr+/-]) or transsulfuration pathways (cystathionine β-synthase [Cbs+/-]) demonstrate mild GC loss and mild vasculopathy. The current work investigated compensation in vivo of one pathway for the other, and, because the transsulfuration pathway yields cysteine necessary for formation of glutathione (GSH), taurine, and hydrogen sulfide (H2S), they were analyzed also. Retinas isolated from wild-type (WT), Mthfr+/-, and Cbs+/- mice (12 and 22 weeks) were analyzed for methylene tetrahydrofolate reductase (MTHFR), cystathionine-β-synthase (CBS), and cystathionase (CTH) RNA/protein levels. Retinas were evaluated for levels of reduced:oxidized GSH (GSH:GSSG), Slc7a11 (xCT), taurine, taurine transporter (TAUT), and H2S. Aside from decreased CBS RNA/protein levels in Cbs+/- retinas, there were minimal alterations in remethylation/transsulfuration pathways in the two mutant mice strains. Glutathione and taurine levels in Mthfr+/- and Cbs+/- retinas were similar to WT, which may be due to robust levels of xCT and TAUT in mutant retinas. Interestingly, levels of H2S were markedly increased in retinas of Mthfr+/- and Cbs+/- mice compared with WT. Ganglion cell loss and vasculopathy observed in Mthfr+/- and Cbs+/- mouse retinas may be milder than expected, not because of compensatory increases of enzymes in remethylation/transsulfuration pathways, but because downstream transsulfuration pathway products GSH, taurine, and H2S are maintained at robust levels. Elevation of H2S is particularly intriguing owing to neuroprotective properties reported for this gasotransmitter.

Telemedicina en Bolivia: proyecto RAFT-Altiplano, experiencias, perspectivas y recomendaciones

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Alejandro Vargas

2014-06-01

Full Text Available OBJETIVO: El objetivo del proyecto RAFT-Altiplano (RAFT, Red Africana Francófona de Telemedicina es evaluar la viabilidad, potencialidad y riesgos de la implementación y el desarrollo de una red de telemedicina en el contexto de un país en desarrollo, como es el caso del Altiplano de Bolivia, para mejorar el acceso a la atención médica y la formación continua en el área rural. En este estudio se describe el desarrollo de dicho proyecto entre 2011 y 2013. MÉTODOS: Se donaron equipos de telemedicina digitales a los centros de salud y se desarrolló una plataforma basada en tecnología Microsoft®integrable con otras tecnologías (con formatos estándares, para gestionar electrónicamente contenidos y documentos clínicos. Se ha capacitado a los profesionales de la salud para realizar las teleconsultas y se ha diseñado un flujo de trabajo de teleconsulta. El sistema de teleenseñanza utilizado es Dudal, porque requiere poco ancho de banda. RESULTADOS: Tras tres años de implementación se dispone de una estructura de trabajo organizada con los diferentes hospitales, instituciones y centros de salud adaptada al contexto latinoamericano para la implementación y utilización de herramientas de teleconsulta y teleenseñanza. El proyecto ha mejorado el acceso a la atención médica especializada en los centros de salud alejados y en los hospitales de tercer nivel de zonas urbanas y ha sido la antesala del desarrollo del proyecto nacional "TeleSalud para Bolivia" promovido por el Ministerio de Salud que contempla la utilización del nuevo satélite boliviano Túpac Katari. CONCLUSIONES: Es viable desarrollar e implementar herramientas de telemedicina en regiones remotas de Bolivia en beneficio de la población cuando se ponen a disposición de las instituciones gubernamentales y municipales de salud y el trabajo entre ellas y los centros asistenciales se realiza de forma coordinada. La comunicación de experiencias, dificultades y riesgos

Adaptive colour contrast coding in the salamander retina efficiently matches natural scene statistics.

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Genadiy Vasserman

Full Text Available The visual system continually adjusts its sensitivity to the statistical properties of the environment through an adaptation process that starts in the retina. Colour perception and processing is commonly thought to occur mainly in high visual areas, and indeed most evidence for chromatic colour contrast adaptation comes from cortical studies. We show that colour contrast adaptation starts in the retina where ganglion cells adjust their responses to the spectral properties of the environment. We demonstrate that the ganglion cells match their responses to red-blue stimulus combinations according to the relative contrast of each of the input channels by rotating their functional response properties in colour space. Using measurements of the chromatic statistics of natural environments, we show that the retina balances inputs from the two (red and blue stimulated colour channels, as would be expected from theoretical optimal behaviour. Our results suggest that colour is encoded in the retina based on the efficient processing of spectral information that matches spectral combinations in natural scenes on the colour processing level.

The Retina Algorithm

CERN Multimedia

CERN. Geneva; PUNZI, Giovanni

2015-01-01

Charge particle reconstruction is one of the most demanding computational tasks found in HEP, and it becomes increasingly important to perform it in real time. We envision that HEP would greatly benefit from achieving a long-term goal of making track reconstruction happen transparently as part of the detector readout ("detector-embedded tracking"). We describe here a track-reconstruction approach based on a massively parallel pattern-recognition algorithm, inspired by studies of the processing of visual images by the brain as it happens in nature ('RETINA algorithm'). It turns out that high-quality tracking in large HEP detectors is possible with very small latencies, when this algorithm is implemented in specialized processors, based on current state-of-the-art, high-speed/high-bandwidth digital devices.

Aspectos relativos a la salud laboral y los riesgos psicosociales de los equipos de proyectos

OpenAIRE

Donate Fernández, Alejandro

2013-01-01

Es el objetivo del presente trabajo presentar una serie de directrices relacionadas con la salud laboral y los riesgos psicosociales de los equipos de proyectos y, en algunos aspectos centrándose en el principal responsable: el director de proyecto.

Glycinergic pathways in the goldfish retina

International Nuclear Information System (INIS)

Marc, R.E.; Lam, D.M.

1981-01-01

Autoradiographic localization of high affinity [3H]glycine uptake in the retina of the goldfish has been used to study some anatomical and physiological properties of potentially glycinergic neurons. There are two classes of retinal cells exhibiting high affinity glycine uptake: Aa amacrine cells and I2 interplexiform cells. Aa amacrine cells constitute about 20% of the somas in the amacrine cell layer and send their dendrites to the middle of the inner plexiform layer. There they are both pre- and postsynaptic primarily to other amacrine cells. Photic modulation of glycine uptake indicates that they are probably red-hyperpolarizing/green-depolarizing neurons. I2 interplexiform cells are a newly discovered type of interplexiform cell; in the outer plexiform layer, they receive direct synaptic input from the somas of red-dominated GABAergic H1 horizontal cells and are apparently presynaptic to dendrites of unidentified types of horizontal cells. The connections of I2 interplexiform cells have not been successfully characterized in the inner plexiform layer. These findings extend our knowledge of neurochemically specific pathways in the cyprinid retina and indicate that glycine, like GABA, is a neurotransmitter primarily involved with circuits coding ''red'' information

Análisis de las causas determinantes en el desempeño de los proyectos en Alianza de Servicios Sociales de Caldas

OpenAIRE

Salinas Ávila, Sandra Liliana

2011-01-01

El resultado del presente trabajo de investigación, muestra las causas que determinan el desempeño de los proyectos en Alianza de Servicios Sociales de Caldas, se basa en el análisis de factores como gestión de proyectos, contribución de los proyectos a las organizaciones, los proyectos y la planificación estratégica, gestión estratégica, influencia de la estructura y cultura de la organización en la gestión de proyectos y gerente de proyectos.

Atrofia girata de coróide e retina : relato de caso

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Oyamaguchi Emerson Kenji

2003-01-01

Full Text Available OBJETIVO: Relatar um caso de atrofia girata de coróide e retina com confirmação por meio da bioquímica do plasma. MÉTODO: Aferiu-se a melhor acuidade visual corrigida de ambos olhos (AO em tabela de Snellen. Foram realizados biomicroscopia do segmento anterior, refração, mapeamento de retina, angiografia fluoresceínica, campo visual e dosagem da ornitina sérica (aminoacidograma. RESULTADOS: Paciente de 22 anos, sexo feminino, cor branca, apresentando alta miopia e acuidade visual (AV 20/100 em AO. À biomicroscopia do segmento anterior apresentava catarata subcapsular posterior em AO. À oftalmoscopia foram verificadas lesões atróficas da coróide e da retina bem delimitadas em meia periferia de AO. O aminoacidograma constatou elevação correspondente ao complexo da ornitina. CONCLUSÃO: Relata-se um caso típico de atrofia girata, distrofia retiniana rara associada a hiperornitinemia.

Proyecto ROSE: relevancia de la educación científica

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Acevedo; J.A.

2005-09-01

Full Text Available Una ciencia escolar con poca relevancia personal y social es, ciertamente, un serio obstáculo para favorecer el interés hacia esta materia y conseguir mejorar su aprendizaje. La revista Eureka ya ha abordado en otro lugar este importante problema curricular en relación con las finalidades educativas de la enseñanza de las ciencias (Acevedo, 2004. En esta ocasión se comentará brevemente un proyecto internacional que se ocupa de esta cuestión clave, el proyecto ROSE.

Linezolid-induced optic neuropathy with a rare pathological change in the inner retina.

Science.gov (United States)

Ishii, Nobuhito; Kinouchi, Reiko; Inoue, Masatomo; Yoshida, Akitoshi

2016-12-01

We report a case of linezolid-induced optic neuropathy with transient microcystic spaces in the inner retina. We observed the retina using Fourier-domain optical coherence tomography (FD-OCT) in a patient with linezolid-induced optic neuropathy. A 49-year-old woman presented to our department with a 1-week history of bilateral photophobia. At the first visit, her best-corrected visual acuity (VA) was 0.6 in the right eye and 0.5 in the left eye. She had moderate optic disk edema and central scotomas bilaterally. FD-OCT showed bilateral microcystic spaces in the retina. Microcystic spaces were seen in the retinal nerve fiber layer (RNFL) and at the border of the RNFL and the retinal ganglion cell layer. Magnetic resonance imaging and laboratory tests showed no positive findings except for an elevated lactic acid level. One week after the first visit, the VA levels decreased to 0.06 and 0.07 in the right and left eyes, respectively. Because the patient had a 7-month history of linezolid treatment for persistent pyogenic arthritis, we suspected linezolid-induced optic neuropathy and immediately terminated treatment with this drug. The optic disk edema and the microcystic spaces in the retina resolved, and the VA improved to 1.2 at 6 weeks after linezolid withdrawal. Microcystic spaces, which resolved with linezolid withdrawal, were observed in linezolid-induced optic neuropathy. The microcystic spaces in the inner retina can be the first retinal sign of some optic neuropathies.

Comparative proteomic analyses of macular and peripheral retina of cynomolgus monkeys (Macaca fascicularis).

Science.gov (United States)

Okamoto, Haru; Umeda, Shinsuke; Nozawa, Takehiro; Suzuki, Michihiro T; Yoshikawa, Yasuhiro; Matsuura, Etsuko T; Iwata, Takeshi

2010-01-01

The central region of the primate retina is called the macula. The fovea is located at the center of the macula, where the photoreceptors are concentrated to create a neural network adapted for high visual acuity. Damage to the fovea, e.g., by macular dystrophies and age-related macular degeneration, can reduce central visual acuity. The molecular mechanisms leading to these diseases are most likely dependent on the proteins in the macula which differ from those in the peripheral retina in expression level. To investigate whether the distribution of proteins in the macula is different from the peripheral retina, proteomic analyses of tissues from these two regions of cynomolgus monkeys were compared. Two-dimensional gel electrophoresis and mass spectrometry identified 26 proteins that were present only in the macular gel spots. The expression levels of five proteins, cone photoreceptor specific arrestin-C, gamma-synuclein, epidermal fatty acid binding protein, tropomyosin 1alpha chain, and heterogeneous nuclear ribonucleoproteins A2/B1, were significantly higher in the macula than in the peripheral retina. Immunostaining of macula sections by antibodies to each identified protein revealed unique localization in the retina, retinal pigment epithelial cells and the choroidal layer. Some of these proteins were located in cells with higher densities in the macula. We suggest that it will be important to study these proteins to determine their contribution to the pathogenesis and progression of macula diseases.

Gestión de Proyectos de Software

OpenAIRE

Sáez Vacas, Fernando

1994-01-01

Apuntes pertenecientes al Programa de Postgrado en Sistemas y Redes de Comunicaciones impartidos en la E.T.S.I. de Telecomunicación. Realizan una introducción intuitiva de la importancia de las técnicas de gestión y de los factores humanos en la gestión de proyectos de software.

MODELO PARA LA EVALUACIÓN Y GESTIÓN DE PROYECTOS TECNOLÓGICOS (NOACH

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Yudit Coromoto Sánchez Meza

2018-01-01

Full Text Available La permanente evolución tecnológica, los complejos patrones de tráfico y altos niveles de disponibilidad y calidad que caracterizan a los sistemas de telecomunicaciones, aunado a los riesgos e incertidumbre inherentes a las tecnologı́as, redundan en una gran complejidad en la evaluación y análisis para cumplir con los múltiples criterios y requerimientos técnicos y económicos, que marcan la toma de decisiones para uso óptimo de los recursos en un proyecto de telecomunicaciones. En este artículo, se desarrolla el sistema Noach, un Modelo para la Evaluación y Gestión de Proyectos Tecnológicos, basado en las mejores prácticas del Grupo de Conocimientos en Administración de Proyectos, Librería de Infraestructura de Tecnologı́as de Información e Integración de Modelos de Madurez de Capacidades para Desarrollo. Se trata de una herramienta computacional desarrollada en software libre, usando arquitectura de tres capas, que captura y procesa los datos asociados a diferentes factores y variables de alta incertidumbre y riesgo, para evaluar proyectos tecnológicos. La estructura de Noach es adaptable a la amplia gama de tecnologı́as de telecomunicaciones y genera generar diferentes escenarios que se podrı́an presentar en el desarrollo del proyecto y contempla el cálculo de los recursos asignados, relación costos/precios, análisis de mercado y calendario de trabajo.

Ultrasound-mediated nanoparticle delivery across ex vivo bovine retina after intravitreal injection.

Science.gov (United States)

Huang, Di; Chen, Ying-Shan; Thakur, Sachin S; Rupenthal, Ilva D

2017-10-01

Intravitreal injection is the most common administration route for the treatment of retinal diseases. However, the vitreous and some of the retinal layers themselves act as significant barriers to efficient delivery of drugs administered intravitreally. This study aimed to improve the diffusive mobility of nanoparticles (NPs) in the vitreous and enhance their permeation across the retina after intravitreal injection by application of ultrasound (US). Ex vivo posterior bovine eye cups were used and the vitreous was either left intact or removed gently from the neural retina. Hyaluronic acid coated human serum albumin NPs were administered into the eye cups and continuous US with a frequency of 1MHz, an intensity of 0.5W/cm 2 , and a duration of 30s was applied once or repeatedly via the transscleral route. After pre-determined time points, fluorescence intensities in the vitreous and the retina were analyzed. Short pulses of US significantly improved the diffusive mobility of NPs through the vitreous as well as their penetration across the neural retina into the retinal pigment epithelium and choroid without causing any detectable damage to the ocular tissues. Therefore, transscleral US could be a powerful and safe tool to enhance retinal delivery of intravitreally injected NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

San Fernando: ¿utopía o proyecto inconcluso?

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Juan Pablo Murillo

2008-06-01

Full Text Available El estudio analiza los distintos proyectos de modernización ocurridos en la Facultad de Medicina de San Fernando, en el contexto de una seria crisis institucional a finales del siglo XX. Para ello, a partir de las categorías de colectivo de pensamiento y estilo de pensamiento propuestos por Ludwick Fleck, se hace un estudio de los procesos socio-históricos relacionados con los distintas iniciativas desplegadas en la más antigua escuela de medicina del Perú. Un análisis de las diferentes iniciativas identificadas nos llevan a la hipótesis de que la crisis de San Fernando, como colectivo académico, se basa en las contradicciones propias de un proyecto institucional inconcluso, que además cíclicamente se manifiesta asincrónico y disfuncional, al complejo y cambiante entorno institucional y cultural de la sociedad peruana. El estudio sistematiza las principales características de los diferentes proyectos de modernización institucional. Luego de un análisis del actual contexto del sector salud peruano, a partir de los procesos identificados, se propone una agenda de desarrollo, orientada a generar un ciclo de acumulación y crecimiento académico, que constituya una etapa de transición de cara a los retos que el siglo XXI plantea a los miembros del colectivo San Fernandino.

Defects in the outer limiting membrane are associated with rosette development in the Nrl-/- retina.

Directory of Open Access Journals (Sweden)

Michael W Stuck

Full Text Available The neural retinal leucine zipper (Nrl knockout mouse is a widely used model to study cone photoreceptor development, physiology, and molecular biology in the absence of rods. In the Nrl(-/- retina, rods are converted into functional cone-like cells. The Nrl(-/- retina is characterized by large undulations of the outer nuclear layer (ONL commonly known as rosettes. Here we explore the mechanism of rosette development in the Nrl(-/- retina. We report that rosettes first appear at postnatal day (P8, and that the structure of nascent rosettes is morphologically distinct from what is seen in the adult retina. The lumen of these nascent rosettes contains a population of aberrant cells protruding into the subretinal space that induce infolding of the ONL. Morphologically adult rosettes do not contain any cell bodies and are first detected at P15. The cells found in nascent rosettes are photoreceptors in origin but lack inner and outer segments. We show that the adherens junctions between photoreceptors and Müller glia which comprise the retinal outer limiting membrane (OLM are not uniformly formed in the Nrl(-/- retina and thus allow protrusion of a population of developing photoreceptors into the subretinal space where their maturation becomes delayed. These data suggest that the rosettes of the Nrl(-/- retina arise due to defects in the OLM and delayed maturation of a subset of photoreceptors, and that rods may play an important role in the proper formation of the OLM.

Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus

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C.L. Tanan

2006-07-01

Full Text Available Methyl mercury (MeHg is highly neurotoxic, affecting visual function in addition to other central nervous system functions. The effect of mercury intoxication on the amplitude of horizontal cell responses to light was studied in the retina of the fish Hoplias malabaricus. Intracellular responses were recorded from horizontal cells of fish previously intoxicated with MeHg by intraperitoneal injection (IP group or by trophic exposure (T group. Only one retina per fish was used. The doses of MeHg chloride administered to the IP group were 0.01, 0.05, 0.1, 1.0, 2.0, and 6.0 mg/kg. The amplitudes of the horizontal cell responses were lower than control in individuals exposed to 0.01 (N = 4 retinas, 0.05 (N = 2 retinas and 0.1 mg/kg (N = 1 retina, whereas no responses were recorded in the 1.0, 2.0, and 6.0 mg/kg groups. T group individuals were fed young specimens of Astyanax sp previously injected with MeHg corresponding to 0.75 (N = 1 retina, 0.075 (N = 8 retinas or 0.0075 (N = 4 retinas mg/kg fish body weight. After 14 doses, one every 5 days, the amplitude of the horizontal cell response was higher than control in individuals exposed to 0.075 and 0.0075 mg/kg, and lower in individuals exposed to 0.75 mg/kg. We conclude that intoxication with MeHg affects the electrophysiological response of the horizontal cells in the retina, either reducing or increasing its amplitude compared to control, and that these effects are related to the dose and/or to the mode of administration.

Diagnóstico de la madurez de la gestión de proyectos en DITRANSA

OpenAIRE

Gómez Acosta, Victoria Eugenia

2014-01-01

Este trabajo propone el uso de la metodología del estándar para administración de proyectos (Organizational Project Management - OPM3) publicado por el Project Management Institute (PMI) -- El estándar permite identificar qué debe hacerse para que las organizaciones puedan plasmar las buenas prácticas en sus proyectos, programas y portafolios y realizar el diagnóstico de la madurez actual en gestión de proyectos de la Compañía de Distribución y Transporte S.A. – Ditransa, una compañía pertene...

Two-photon excited autofluorescence imaging of freshly isolated frog retinas.

Science.gov (United States)

Lu, Rong-Wen; Li, Yi-Chao; Ye, Tong; Strang, Christianne; Keyser, Kent; Curcio, Christine A; Yao, Xin-Cheng

2011-06-01

The purpose of this study was to investigate cellular sources of autofluorescence signals in freshly isolated frog (Rana pipiens) retinas. Equipped with an ultrafast laser, a laser scanning two-photon excitation fluorescence microscope was employed for sub-cellular resolution examination of both sliced and flat-mounted retinas. Two-photon imaging of retinal slices revealed autofluorescence signals over multiple functional layers, including the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Using flat-mounted retinas, depth-resolved imaging of individual retinal layers further confirmed multiple sources of autofluorescence signals. Cellular structures were clearly observed at the PRL, ONL, INL, and GCL. At the PRL, the autofluorescence was dominantly recorded from the intracellular compartment of the photoreceptors; while mixed intracellular and extracellular autofluorescence signals were observed at the ONL, INL, and GCL. High resolution autofluorescence imaging clearly revealed mosaic organization of rod and cone photoreceptors; and sub-cellular bright autofluorescence spots, which might relate to connecting cilium, was observed in the cone photoreceptors only. Moreover, single-cone and double-cone outer segments could be directly differentiated.

Un acercamiento a la didáctica de las lenguas extranjeras para niños. "Para que cante la voz"

OpenAIRE

Delgado de Valencia, Sonia

1998-01-01

Este pequeño texto tiene como objetivo divulgar las experiencias que se han recogido en el área de la didáctica de las lenguas extranjeras para niños, en especial en la enseñanza del inglés y del francés, tanto en la Universidad Nacional de Colombia como en otras instituciones del país y del exterior, a las cuales hemos podido acceder varios profesores colombianos. / Contenido. Preliminares; Capítulo 1 - Un acercamiento a la didáctica de las lenguas extranjeras para niños; Capítulo 2 -...

Hacia un proyecto "democrático-expansivo" de transparencia

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Irma Eréndira Sandoval Ballesteros

2013-01-01

Full Text Available El artículo explora la paradoja que resulta de los avances normativos e institucionales de la transparencia vis-a-vis las insuficiencias prácticas y políticas, a través del lente de una disputa creciente entre tres proyectos distintos y contrapuestos de transparencia: el burocrático, el de ‘relaciones públicas’, y el ‘democrático-expansivo’. La razón principal por la que México no ha podido colmar las promesas de sus reformas institucionales es precisamente la prevalencia de las dos primeras concepciones. México, así como otros países en situación similar, necesita rebasar este tipo de enfoques parciales para adoptar plenamente un proyecto que profundice y expanda la democracia misma.

La escritura de Simone de Beauvoir como proyecto global

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Olga Grau Duhart

2014-05-01

Full Text Available El artículo señala algunas de las propiedades de la escritura de Simone de Beauvoir, escritura que, si bien adopta diversos registros, condensa su preocupación filosófica de afirmación plena de la existencia y del llegar a ser a partir del ejercicio de la acción de escribir. Uno de los conceptos clave del existencialismo es el de proyecto, que en su caso particular se resuelve globalmente como escritura, movida, en particular, por la pulsión de comprensión del mundo y de la manifestación de una voluntad emancipatoria. La escritura de Simone de Beauvoir es medio y fin para el cumplimiento de su proyecto esencial de saber y comprender el mundo y actuar en él.

Circulating Reactive Oxidant Causes Apoptosis of Retinal Pigment Epithelium and Cone Photoreceptors in the Mouse Central Retina

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Wei Wang

2011-01-01

Full Text Available Reactive oxidants damage the retinal pigment epithelium (RPE, which is required for viability of overlying photoreceptors. Smoking which leads to chronic accumulation of reactive oxidants in the circulation is linked to age-related macular degeneration (AMD where RPE death is seen along with photoreceptor loss in the central macular region of the retina. It is unclear why this damage is concentrated in the central retina. We asked whether circulating oxidant might specifically target the central retina. Mice were administered the classic reactive oxidant iodate through tail vein injection, and visual acuity was followed by optokinetic response. Histology and apoptosis was examined by H&E and immunostaining. Iodate indeed selectively damaged the central retina, and this damage was highlighted by early apoptosis of RPE in the central retina followed by apoptosis of photoreceptors adjacent to the region of RPE loss–-cones were lost preferentially. The pattern and extent of this damage was independent of exposure to light. We then conclude that circulating oxidant is sufficient to selectively damage the central retina highlighted by sequential apoptosis of RPE and photoreceptors, with cones being the most sensitivity to this RPE loss.

Preservation of Retina Ganglion Cell Function by Morphine in a Chronic Ocular-Hypertensive Rat Model

OpenAIRE

Husain, Shahid; Abdul, Yasir; Crosson, Craig E.

2012-01-01

Morphine, a broad range opioid-receptors agonist, provides retina neuroprotection against glaucomatous injury in chronic experimental rat model. Morphine-induced retina neuroprotection in glaucoma model is mediated partly via inhibition of TNF-alpha production and caspase-3 and caspase-8 activation.

1922: acercamiento a los contextos y alrededores de Trilce

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Diana Rodríguez Sánchez

2012-05-01

Full Text Available El presente análisis tiene como finalidad realizar un acercamiento al poemario Trilce, de César Vallejo, a partir de su relación con el contexto y las lecturas próximas a 1922, año de su publicación. En los albores del siglo XX, el hombre moderno cuestiona los discursos impuestos por la lógica y la razón, bajo una tradición que hizo de la metafísica el único camino de conocimiento del ser. Los alrededores a los que se acude son el poema La tierra baldía y enfoques que abordan la crisis del sujeto y la posición radical del lenguaje, con el propósito de ofrecer posibles rutas de lectura acerca del poemario. The aim of this analysis is to get a better understanding of the collection of poems Trilce, by César Vallejo, viewing it in relation to the context and writings of its time, about 1922, the year of its publication. At the beginnings of the 20th century, modern man began to question the lessons derived from the logic and reasoning of the metaphysical tradition, at that time the only path to knowledge of being. Trilce will be analysed in light of the following texts and theories: The Waste Land, theories and texts that talk about the crisis of the subject and the radical position of language. The purpose of this analysis will be to offer possible routes of reading for the Trilce collection of poems.

Mejora de Procesos para la Administración de Proyectos en Instituciones de nivel Superior

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Josefina García Durán

2015-02-01

Full Text Available Las instituciones educativas de nivel superior presentan características comunes que obstaculizan la implementación de prácticas eficientes de administración de proyectos, entre las que se puede mencionar: poca estandarización para administrar los proyectos y metodologías deficientes para el control del alcance, tiempo y costos del proyecto. Además, existe una falta de definición de roles y responsabilidades, planificación débil y en algunas ocasiones nula. Como resultado, se definen vagamente los informes, eventos, canales de comunicación y no se documentan las lecciones aprendidas. En este artículo se presenta un marco de trabajo para la definición y mejora de procesos de administración de proyectos basado en la extracción del conocimiento tácito de la institución y tomando como referencia el PMBOK.

Fotocoagulação a laser em pacientes portadores de descolamento de retina regmatogênico periférico

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Paulo Escarião

2013-08-01

Full Text Available OBJETIVO: Relatar uma série de casos de descolamento de retina sem envolvimento macular tratados com fotocoagulação a laser. MÉTODOS: Estudo tipo série de casos envolvendo 14 olhos de 12 pacientes com descolamento de retina regmatogênico sem envolvimento macular, retrospectivo, de intervenção. Olhos com procedimentos cirúrgicos prévios foram excluídos. A fotocoagulação a laser foi aplicada com três fileiras confluentes de spot de 300μm, posterior ao descolamento de retina, se extendendo até a ora serrata. A melhor acuidade visual corrigida pré e pós-operatória e a progressão do descolamento de retina foram registrados durante o estudo. RESULTADOS: Treze olhos necessitaram de apenas uma sessão de laser para conter o descolamento de retina. Apenas um olho necessitou de intervenção adicional por causa da evolução do descolamento de retina. Miopia foi encontrada em 7 olhos. Todos os pacientes mantiveram acuidade visual corrigida igual ou melhor que 20/30. CONCLUSÃO:Em casos bem selecionados, a fotocoagulação a laser pode ser considerada para o tratamento de descolamento de retina regmatogênico.

Los Teres: un asentamiento ordenador del territorio Preguane-Guane. Una aproximación al tema urbano

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Leonardo Moreno González

2013-01-01

Full Text Available Este artículo, es el resultado de una reflexión teórica y de los datos obtenidos en el proyecto arqueológico estudio del patrimonio arqueológico, paisajístico y geo- ambiental de la mesa de los santos. bases para proyectos de eco-desarrollo (código 5254. El proyecto se implementó en el 2012, en la vereda Los Teres, municipio de Los Santos, Santander, Colombia, el cual se desarrolló bajo el marco teórico de la arqueología del paisaje. De los resultados obtenidos, sólo tomamos la parte concerniente a los sitios de vivienda (asentamientos y el arreglo de éstos en el paisaje, con el propósito de comprender la distribución espacial de los asentamientos, en el contexto territorial y, con ello, comprender su estructura física edificada del asentamiento, como fuente primigenia para lograr un acercamiento al tema urbano desde la fuente documental prehispánica.

Simulating the Effects of Laser Damage to the Retina

National Research Council Canada - National Science Library

2001-01-01

This Phase II SBIR brought vision and signal processing researchers from the Air Force, academia and the public sector together to develop a visualization tool for modeling laser damage to the retina...

Excess lead in the neural retina in age-related macular degeneration.

Science.gov (United States)

Erie, Jay C; Good, Jonathan A; Butz, John A

2009-12-01

To measure lead and cadmium in retinal tissues of human donor eyes with and without age-related macular degeneration (AMD). Laboratory investigation. Lead and cadmium concentrations in retinal tissues (neural retina and retinal pigment epithelium [RPE]-choroid complex) in 25 subjects with AMD (50 donor eyes) and 36 normal subjects (72 donor eyes) were determined by using inductively coupled plasma-mass spectrometry. Severity of AMD was graded by using color fundus photographs and the Minnesota Grading System. Differences in metal concentrations were compared by using Wilcoxon rank-sum tests. The neural retinas of subjects with AMD had increased lead concentrations (median, 12.0 ng/g; 25% to 75% interquartile range, 8 to 18 ng/g; n = 25) compared with normal subjects (median, 8.0 ng/g; 25% to 75% interquartile range, 0 to 11 ng/g; P = .04; n = 36). There was no difference in lead concentration in the RPE-choroid complex between subjects with AMD (median, 198 ng/g; 25% to 75% interquartile range, 87 to 381 ng/g) and normal subjects (median, 172 ng/g; 25% to 75% interquartile range, 100 to 288 ng/g; P = .25). Cadmium concentration in the neural retina (median, 0.9 microg/g; 25% to 75% interquartile range, 0.7 to 1.8 microg/g) and RPE-choroid complex (median, 2.2 microg/g; 25% to 75% interquartile range, 1.8 to 3.7 microg/g) in subjects with AMD was not different from concentrations in the neural retina (median, 0.9 microg/g; 25% to 75% interquartile range, 0.7 to 1.4 microg/g; P = .32) and RPE-choroid complex (median, 1.5 microg/g; 25% to 75% interquartile range, 0.9 to 2.5 microg/g; P = .12) of normal subjects. AMD is associated with excess lead in the neural retina, and this relationship suggests that metal homeostasis in AMD eyes is different from normal.

Sutatenza: retos y sueños de un proyecto radial

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Gabriel Gómez Mejía

2012-01-01

Full Text Available Nacida en la mitad del siglo pasado. Radio Sutatenza - y la organización en la que se inserta. Acción Cultural Popular- desempeñó un papel importante en la modernización del país, en particular del país campesino, al tiempo que servía a interese conservadores. Aquí daremos repaso a la forma como este proyecto radial llamado Radio Sutatenza y su correspondiente proyecto social, conocido como Acción Cultural Popular (ACPO, se hicieron eco de los sueños de cambio y transformación que desde su origen provocó el primer medio electrónico en la hitoria de la humanidad.

Myopathy associated with pigmentary degeneration of the retina and high protein content of cerebrospinal fluid Miopatia associada a degeneração pigmentar da retina e hiperproteinorraquia

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José Antonio Levy

1974-06-01

Full Text Available The cases of two brothers suffering from a myopathy associated with pigmentary degeneration of the retina and increase of protein content of the cerebrospinal fluid are reported.Foram estudados dois pacientes, filhos de pais não consanguíneos, com quadro miopático, iniciado na segunda década da vida, com predomínio na musculatura das cinturas e da face. Em ambos os casos havia degeneração pigmentar da retina e aumento da taxa protéica no líquido cefalorraqueano.

Proyecto de viabilidad: creación de una empresa de mantenimiento industrial y gestión energética

OpenAIRE

Morán Rodríguez, Cristian

2012-01-01

El autor de este Proyecto Final de Carrera ha cursado los estudios de Ingeniería en Organización Industrial, es por eso que se plantea un proyecto que englobe los conocimientos adquiridos en esta especialidad. Para la selección de este proyecto, se tuvieron en cuenta diferentes alternativas. Entre todas ellas se optó por un Proyecto de viabilidad para la Creación de una empresa dedicada al mantenimiento industrial y la gestión energética, ya que, teniendo presente el momento so...

Gestión multi-variable inteligente de equipos multidisciplinarios e internacionales de equipos y proyectos de desarrollo de software

OpenAIRE

Luque Calvo, Ana

2013-01-01

Este proyecto abarca por un lado el campo de ingeniería del software, y por otro lado, el campo de la Inteligencia Artificial (IA) dentro de la rama de aprendizaje automático. El objetivo principal de este proyecto ha sido desarrollar un sistema que sea capaz de predecir y calcular la productividad generada por un equipo de trabajo a la hora de desarrollar un proyecto antes de formar el equipo de trabajo y comenzar el desarrollo del proyecto. Además, se predecirá la formació...

Light regulation of the insulin receptor in the retina.

Science.gov (United States)

Rajala, Raju V S; Anderson, Robert E

2003-10-01

The peptide hormone insulin binds its cognate cell-surface receptors to activate a coordinated biochemical-signaling network and to induce intracellular events. The retina is an integral part of the central nervous system and is known to contain insulin receptors, although their function is unknown. This article, describes recent studies that link the photobleaching of rhodopsin to tyrosine phosphorylation of the insulin receptor and subsequent activation of phosphoinositide 3- kinase (PI3K). We recently found a light-dependent increase in tyrosine phosphorylation of the insulin receptor-beta-subunit (IR beta) and an increase in PI3K enzyme activity in isolated rod outer segments (ROS) and in anti-phosphotyrosine (PY) and anti-IR beta immunoprecipitates of retinal homogenates. The light effect, which was localized to photoreceptor neurons, is independent of insulin secretion. Our results suggest that light induces tyrosine phosphorylation of IR beta in outer-segment membranes, which leads to the binding of p85 through its N-terminal SH2 domain and the generation of PI-3,4,5-P3. We suggest that the physiological role of this process may be to provide neuroprotection of the retina against light damage by activating proteins that protect against stress-induced apoptosis. The studies linking PI3K activation through tyrosine phosphorylation of IR beta now provide physiological relevance for the presence of these receptors in the retina.

Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

Science.gov (United States)

Omori, Yoshihiro; Katoh, Kimiko; Sato, Shigeru; Muranishi, Yuki; Chaya, Taro; Onishi, Akishi; Minami, Takashi; Fujikado, Takashi; Furukawa, Takahisa

2011-01-01

In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO) mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

Directory of Open Access Journals (Sweden)

Yoshihiro Omori

Full Text Available In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

Effects of hyperbaric oxygen on crystalline lens and retina in nicotine-exposed rats.

Science.gov (United States)

Ari, Seyhmus; Nergiz, Yusuf; Cingü, Abdullah Kürşat; Atay, Ahmet Engin; Sahin, Alparslan; Cinar, Yasin; Caca, Ihsan

2013-03-01

To determine histopathological changes on crystalline lens and retina of rats after subcutaneous injection of nicotine and to examine the effects of hyperbaric oxygen (HBO) on these changes related to nicotine exposure. Twenty-eight female Sprague-Dawley rats were enrolled in the study and the rats were divided into four equal sized groups randomly (Group N: the rats exposed only to nicotine, group HB: the rats received only HBO, group N+HB: the rats that underwent to nicotine injection and subsequently received HBO, group C: the control group that neither exposed to nicotine nor received HBO). The rats were sacrificed by decapitation method and all were enucleated immediately after scarification. Tissue samples from crystalline lens, lens capsule, and the retina from the right eyes of the rats were examined by light microscopy. While the histological appearances of the retina and the lens was similar in group HB, group N+HB, and the control group; group N showed some pathological changes like decrement in the retinal ganglion cell density, atrophy of the retinal nerve fiber layer, congestion of the vessels in the optic nerve head, thinning of the internal plexiform layer, thinning of the lens capsule, and transformation of the anterior subcapsular epithelium into squamous epithelia. Subcutaneous injection of nicotine was found to be related with some pathological changes in the retina and lens of the Sprague-Dawley rats. However HBO caused no significant negative effect. Furthermore, the histopathological changes related to nicotine exposure in the lens and retina of the rats recovered by the application of HBO.

Ingeniería de proyectos de explotación de información para PyMEs

OpenAIRE

García Martínez, Ramón; Lelli, R.; Merlino, Hernán; Cornachia, Luis; Rodríguez, D.; Pytel, Pablo; Arboleya, Hernán

2011-01-01

Los proyectos de explotación de información poseen características muy distintas a las de los proyectos de desarrollo de software tradicionales. Las clásicas etapas de análisis, diseño, desarrollo, integración y testeo, no encajan con las etapas naturales de los procesos de desarrollo de este tipo de proyectos. En consecuencia, herramientas de la Ingeniería de Software clásica tales como la ingeniería de requerimientos, los modelos de procesos, los ciclos de vida e incluso los mapas de activi...

Effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats

Institute of Scientific and Technical Information of China (English)

Xiao Liu

2016-01-01

ABSTRACT Objective:To study the effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats.Methods:SD rats were selected as experimental animals and divided into control group, model group and ozone group, and after diabetic models were built, ozone enema was conducted. Retina tissue was collected, TUNEL kits were used to detect the number of apoptotic cells, and Elisa kits were used to detect the contents of nerve damage molecules, angiogenesis-related molecules and endoplasmic reticulum stress molecules. Results:The number of apoptotic cells in retina tissue of model group was significantly more than that of control group, and the number of apoptotic cells in retina tissue of ozone group was significantly less than that of model group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of model group were significantly higher than those of control group, and PEDF content was lower than that of control group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of ozone group were significantly lower than those of model group, and PEDF content was higher than that of model group.Conclusion:Ozone therapy can reduce the number of apoptotic cells while reduce nerve cell injury and inhibit angiogenesis and endoplasmic reticulum stress in retina tissue of diabetic rats.

Matemáticas, materiales manipulativos y rutinas Proyecto para segundo de Primaria

OpenAIRE

Fraile-Bravo, Maria

2017-01-01

Este trabajo presenta un proyecto que pretende crear una rutina de trabajo en el aula de segundo de primaria, en la cual se trabajen las matemáticas con materiales manipulativos. Esta forma de trabajar tiene el objetivo de mejorar la competencia matemática de los alumnos y fomentar un espacio en el que los alumnos operen con las matemáticas de manera concreta para después llegar al concepto abstracto correspondiente. Todo lo desarrollado en el proyecto se halla fundamentado en ...

Laureano G?mez Castro y su proyecto de reforma constitucional (1951-1953)

OpenAIRE

Diego Nicol?s, Pardo Motta

2008-01-01

"El gobierno de Laureano G?mez Castro, uno de los m?s controvertidos de la historia de Colombia, se caracteriz? no s?lo por la agudizaci?n de la violencia partidista, sino tambi?n por la elaboraci?n de un proyecto de reforma constitucional, claramente influenciado por ideas de derecha. Dicho proyecto fue olvidado en las bibliotecas a partir del derrocamiento de G?mez. Sin embargo, su an?lisis es profundamente necesario tanto para la revisi?n de la influencia de la derecha en Colombia, como pa...

Effects and Responses to Spaceflight in the Mouse Retina

Science.gov (United States)

Zanello, Susana B.; Theriot, Corey; Westby, Christian; Boyle, Richard

2011-01-01

Several stress environmental factors are combined in a unique fashion during spaceflight, affecting living beings widely across their physiological systems. Recently, attention has been placed on vision changes in astronauts returning from long duration missions. Alterations include hyperoptic shift, globe flattening, choroidal folds and optic disc edema, which are probably associated with increased intracranial pressure. These observations justify a better characterization of the ocular health risks associated with spaceflight. This study investigates the impact of spaceflight on the biology of the mouse retina. Within a successful tissue sharing effort, eyes from albino Balb/cJ mice aboard STS-133 were collected for histological analysis and gene expression profiling of the retina at 1 and 7 days after landing. Both vivarium and AEM (Animal Enclosure Module) mice were used as ground controls. Oxidative stress-induced DNA damage was higher in the flight samples compared to controls on R+1, and decreased on R+7. A trend toward higher oxidative and cellular stress response gene expression was also observed on R+1 compared to AEM controls, and these levels decreased on R+7. Several genes coding for key antioxidant enzymes, namely, heme-oxygenase-1, peroxiredoxin, and catalase, were among those upregulated after flight. Likewise, NF B and TGFbeta1, were upregulated in one flight specimen that overall showed the most elevated oxidative stress markers on R+1. In addition, retinas from vivarium control mice evidenced higher oxidative stress markers, NF B and TGFbeta1, likely due to the more intense illumination in vivarium cages versus the AEM. These preliminary data suggest that spaceflight represents a source of environmental stress that translates into oxidative and cellular stress in the retina, which is partially reversible upon return to Earth. Further work is needed to dissect the contribution of the various spaceflight factors (microgravity, radiation) and to

Mesa redonda sobre nuevos modelos organizativos en la gestión de proyectos digitales

OpenAIRE

Taladriz Mas, Margarita; Magriñá Contreras, Marta; Martín Marichal, Carmen; Cabo Rigol, Mercé; X Workshop Rebiun sobre proyectos digitales. Valencia, 7-8 Octubre de 2010

2010-01-01

Mesa redonda dentro del X Workshop Rebiun sobre proyectos digitales, celebrado en Valencia, 7-8 Ocubre de 2010, sobre: Nuevos modelos organizativos en la gestión de proyectos digitales. Moderador: José Manuel Barrueco (UV). Intervienen: Margarita Taladriz Mas(UC3M), Marta Magriñá Contreras (UNIRIOJA), Carmen Martín Marichal (ULPGC) y Mercé Cabo Rigol (UPF).

Increased expression of IRE1α and stress-related signal transduction proteins in ischemia-reperfusion injured retina

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Natsuyo Hata

2008-08-01

Full Text Available Natsuyo Hata1, Toshiyuki Oshitari1,2, Akiko Yokoyama1,3, Yoshinori Mitamura1, Shuichi Yamamoto11Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chuo-ku, Chiba, Japan; 2Department of Ophthalmology, Kimitsu Central Hospital, Kisarazu City, Chiba, Japan; 3Department of Ophthalmology, Inoue Memorial Hospital, Chuo-ku, Chiba, JapanAbstract: The purpose of this study was to determine whether the expression of ER stress-related factors IRE1α, apoptosis signal-regulating kinase 1 (ASK1, SAPK/ERK kinase 1 (SEK1 and c-Jun N-terminal kinase (JNK is associated with the damaged retinal neurons induced by ischemia-reperfusion injury. After 60 minutes of ischemia, the rat retinas were reperfused, and retinas were isolated and fixed after 6, 9, 12, 18, and 24 hours, and 2, 5, and 9 days of reperfusion. Cryosections were immunostained with Fluoro-Jade B, a degenerating neuron marker to label degenerating neurons. Semi-quantitative analysis of the expression of IRE1α, ASK1, SEK1, and JNK were performed in both control and ischemic retinas. In ischemic retinas, the intensities of IRE1α immunoreactivity in the ganglion cell layer (GCL were significantly higher than in the control retinas. In ischemic retinas, the numbers of SEK1-, ASK1-, and JNK-positive cells were significantly increased in the GCL compared to those in the control retinas. In addition, the cells that were positive for SEK1-, ASK1-, and JNK were also positive for Fluoro-Jade B-positive cells. These results indicate that the increased expression of ER stress-related factors was, in part, associated with the retinal neuronal abnormalities after ischemia-reperfusion injury in rat retinas.Keywords: endoplasmic reticulum, IRE1α, apoptosis signal-regulating kinase 1, SAPK/ERK kinase 1, c-Jun N-terminal kinase, Fluoro-Jade B, ischemia-reperfusion injury

Bipolar cell gap junctions serve major signaling pathways in the human retina.

Science.gov (United States)

Kántor, Orsolya; Varga, Alexandra; Nitschke, Roland; Naumann, Angela; Énzsöly, Anna; Lukáts, Ákos; Szabó, Arnold; Németh, János; Völgyi, Béla

2017-08-01

Connexin36 (Cx36) constituent gap junctions (GJ) throughout the brain connect neurons into functional syncytia. In the retina they underlie the transmission, averaging and correlation of signals prior conveying visual information to the brain. This is the first study that describes retinal bipolar cell (BC) GJs in the human inner retina, whose function is enigmatic even in the examined animal models. Furthermore, a number of unique features (e.g. fovea, trichromacy, midget system) necessitate a reexamination of the animal model results in the human retina. Well-preserved postmortem human samples of this study are allowed to identify Cx36 expressing BCs neurochemically. Results reveal that both rod and cone pathway interneurons display strong Cx36 expression. Rod BC inputs to AII amacrine cells (AC) appear in juxtaposition to AII GJs, thus suggesting a strategic AII cell targeting by rod BCs. Cone BCs serving midget, parasol or koniocellular signaling pathways display a wealth of Cx36 expression to form homologously coupled arrays. In addition, they also establish heterologous GJ contacts to serve an exchange of information between parallel signaling streams. Interestingly, a prominent Cx36 expression was exhibited by midget system BCs that appear to maintain intimate contacts with bistratified BCs serving other pathways. These findings suggest that BC GJs in parallel signaling streams serve both an intra- and inter-pathway exchange of signals in the human retina.

Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain

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Jean-François Bouchard

2016-01-01

Full Text Available Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system. Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function. In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing. The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far. It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells. The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.

[Lattice degeneration of the retina].

Science.gov (United States)

Boĭko, E V; Suetov, A A; Mal'tsev, D S

2014-01-01

Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.

Institutionality around the carbon markets and the mechanisms established by the Kyoto Protoco

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Restrepo Restrepo, Piedad Patricia; Tobón Orozco, David Fernando; Flórez Acosta, Jorge Hernán

2008-01-01

El artículo presenta un acercamiento a las instituciones y regulaciones derivadas de la UNFCCC y el Protocolo de Kioto. Se analiza el comportamiento de los mercados de reducción de emisiones en sus ya casi tres años de funcionamiento, especialmente la inestabilidad de los precios en los diversos mercados europeos y su relación con los CER, estos últimos emitidos gracias a los proyectos provenientes del Mecanismo de Desarrollo Limpio (MDL) desarrollados en los países en vías de desarrollo. Se ...

Mass media, espacio y tiempo en Todos Santos, Baja California Sur

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Rossana Almada

2001-01-01

El artículo que aquí se sintetiza es un primer acercamiento, desde la perspectiva de autores entre los que destaca Manuel Castells, a un proyecto mayor que pretende analizar e interpretar el proceso de transformaciones que ha venido sufriendo el pueblo de Todos Santos, Baja California Sur BCS, debido a la llegada de dos contingentes de inmigrantes: el primero, rocedente de Estados Unidos y Canadá, llegó a comprar las casas del centro del pueblo; algunos con la intención de quedarse e inst...

Las categorías de visualización y los movimientos rígidos en el plano del videojuego: un estudio de caso.

OpenAIRE

Acevedo, Jenny; Camargo, Leonor

2011-01-01

El videojuego hace parte de la realidad de los jóvenes de la actualidad. En procura de aprovechar al máximo beneficios del entorno visual del videojuego como: dinamizar la reflexión, desarrollar, en el aula de matemáticas, competencia de resolución de problemas, estimular capacidad deductiva, entre otros, se desarrolló un proyecto que involucraba dichos beneficios en tareas de acercamiento a los conceptos geométricos de rotación y traslación. En esta comunicación, se muestra el efecto positiv...

La visualización en el plano del videojuego: un estudio de caso

OpenAIRE

Acevedo, Jenny; Camargo, Leonor

2011-01-01

El videojuego hace parte de la realidad de los jóvenes de la actualidad. En procura de aprovechar al máximo beneficios del entorno visual del videojuego como: dinamizar la reflexión, desarrollar competencia de resolución de problemas, estimular capacidad deductiva, entre otros, dentro del aula de clase de matemáticas, se desarrolla un proyecto que involucra dichos beneficios dentro de tareas de acercamiento a los conceptos geométricos de rotación y traslación. Además se muestra el efecto p...

Periodismo gráfico entre democracia y dictadura. El Sol de Quilmes a través de sus editoriales

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Alberico, Anahí; Bernat, María Sofía; Castiglione, María Belén; Taboada, Mirta

2015-01-01

El presente artículo, enmarcado en el proyecto de extensión de la Universidad Nacional de Quilmes, “Universidad por la Identidad”, realiza un primer acercamiento analítico a las editoriales del diario El Sol de la localidad mencionada. El corpus de análisis se limita a los textos correspondientes al primer semestre de 1976, es decir que abarca tanto al gobierno de María Estela Martínez de Perón como los primeros meses de la última dictadura cívico-militar. Se trabaja desde la perspe...

Lipid nanoparticles as drug/gene delivery systems to the retina.

Science.gov (United States)

del Pozo-Rodríguez, Ana; Delgado, Diego; Gascón, Alicia R; Solinís, Maria Ángeles

2013-03-01

This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug/gene delivery systems for retinal diseases. Most drug products for ocular disease treatment are marketed as eye drop formulations but, due to ocular barriers, the drug concentration in the retina hardly ever turns out to be effective. Up to this date, several delivery systems have been designed to deliver drugs to the retina. Drug delivery strategies may be classified into 3 groups: noninvasive techniques, implants, and colloidal carriers. The best known systems for drug delivery to the posterior eye are intravitreal implants; in fact, some of them are being clinically used. However, their long-term accumulation might impact the patient's vision. On the contrary, colloidal drug delivery systems (microparticles, liposomes, or nanoparticles) can be easily administered in a liquid form. Nanoparticular systems diffuse rapidly and are better internalized in ocular tissues than microparticles. In comparison with liposomes, nanoparticles have a higher loading capacity and are more stable in biological fluids and during storage. In addition, their capacity to adhere to the ocular surface and interact with the endothelium makes these drug delivery systems interesting as new therapeutic tools in ophthalmology. Within the group of nanoparticles, those composed of lipids (Solid Lipid Nanoparticles, Nanostructred Lipid Carriers, and Lipid Drug Conjugates) are more biocompatible, easy to produce at large scale, and they may be autoclaved or sterilized. The present review summarizes scientific results that evidence the potential application of lipid nanoparticles as drug delivery systems for the retina and also as nonviral vectors in gene therapy of retina disorders, although much more effort is still needed before these lipidic systems could be available in the market.

Análisis de los proyectos del sector agropecuario financiados por Colciencias durante el año 2010

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Edison Suárez O.

2013-08-01

Full Text Available Objetivo. Analizar los proyectos del sector agropecuario financiados por Colciencias durante el año 2010. Materiales y métodos. Se utilizó la base de datos de registro de proyectos correspondientes al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuarias para identificar las propuestas presentadas, elegibles y financiadas de las convocatorias del año 2010. Los proyectos se clasificaron con base en la nomenclatura Internacional de la UNESCO para los campos de la ciencia y la tecnología. Se identificó la convocatoria, campos, disciplinas, rama productiva, entidades participantes, departamento de ejecución y montos financiados. Resultados. Durante el año 2010 Colciencias recibió un total de 4.725 propuestas para financiación, de éstas, 790 correspondieron al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuaria. Las disciplinas de los proyectos financiados, fueron en su mayoría pertenecientes al subsector agrícola, seguido por el pecuario y el agroindustrial. Las universidades públicas fueron el tipo de entidad ejecutora al que se le financió un mayor número de proyectos. Los departamentos en los cuales se ejecutó la mayoría de las propuestas financiadas fueron Antioquia, Cundinamarca, Boyacá y Tolima. Conclusiones. El Programa Nacional de Ciencia Tecnología e Innovación Agropecuaria recibió el 16.7% del total de proyectos recibidos por Colciencias en sus convocatorias del año 2010. El mayor número de proyectos recibidos, elegibles y financiables fueron del subsector agrícola y estuvieron presentados y ejecutados por universidades públicas. La inversión total de Colciencias en proyectos del sector agropecuario fue de $32.923.594.000 con un aporte de contrapartida de $33.225.740.000.

Avaliação da autofluorescência do fundo de olho nas distrofias de retina com o aparelho Heidelberg Retina Angiograph2 Evaluation of fundus autofluorescence in hereditary retinal diseases using Heidelberg Retina Angiograph2

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Monique Côco

2007-10-01

Full Text Available OBJETIVOS: Definir características do exame de autofluorescência, verificando sua utilidade no diagnóstico e acompanhamento de distrofias retinianas. MÉTODOS: Participaram do estudo, 28 pacientes, adultos, divididos igualmente em quatro grupos com diagnósticos de doença de Stargardt, distrofia de Cones, retinose pigmentar e voluntários saudáveis para estabelecimento do padrão de normalidade. Em média foram obtidas nove imagens com o filtro para angiofluoresceinografia para a formação da imagem autofluorescente no Heidelberg Retina Angiograph2. As imagens de cada grupo de pacientes foram analisadas para verificar características comuns. RESULTADOS: As imagens fundoscópicas autofluorescentes dos voluntários do grupo controle mostraram área foveal hipoautofluorescente em relação à retina do pólo posterior. As imagens dos portadores de doença de Stargardt, em geral, apresentaram lesão hipoautofluorescente, correspondendo à área macular. As principais alterações da autofluorescência em pacientes com distrofia de cones foram hipoautofluorescência macular com halo hiperautofluorescente. Nos portadores de retinose pigmentar, foram encontrados pigmentos periféricos causando hipoautofluorescência. Na região macular, hipoautofluorescência ou apenas desorganização do pigmento. CONCLUSÃO: O estudo mostrou a existência de padrões de autofluorescência de fundo nas distrofias de retina que permitem o diagnóstico e melhor interpretação da fisiopatogenia destas doenças.PURPOSE: To define characteristics of the fundus autofluorescence examination, verifying usefulness in the diagnosis and care of hereditary retinal diseases. METHODS: 28 patients, adults, divided equally into four groups with diagnoses of Stargardt macular dystrophy, cone dystrophy, retinitis pigmentosa and healthy volunteers for the establishment of the normality pattern. An average of nine images with the filter for fluorescein angiography was obtained

An analog VLSI chip emulating polarization vision of Octopus retina.

Science.gov (United States)

Momeni, Massoud; Titus, Albert H

2006-01-01

Biological systems provide a wealth of information which form the basis for human-made artificial systems. In this work, the visual system of Octopus is investigated and its polarization sensitivity mimicked. While in actual Octopus retina, polarization vision is mainly based on the orthogonal arrangement of its photoreceptors, our implementation uses a birefringent micropolarizer made of YVO4 and mounted on a CMOS chip with neuromorphic circuitry to process linearly polarized light. Arranged in an 8 x 5 array with two photodiodes per pixel, each consuming typically 10 microW, this circuitry mimics both the functionality of individual Octopus retina cells by computing the state of polarization and the interconnection of these cells through a bias-controllable resistive network.

Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice

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Yanhe Wang

2017-11-01

Full Text Available Background/Aims: Retinitis pigmentosa (RP is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Methods: Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1 mice. Results: The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Conclusions: Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP.

Estudio de medidas y proyectos de movilidad ambiental en el entorno europeo

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Moya González, Luis

2011-01-01

Índice Introducción Tablas resumen de medidas ambientales sobre movilidad Medidas específicas para ciudades históricas Mejora del transporte públicoGestión de automóvilesVehículos compartidosInnovación en vehículos y carburantesTransporte de mercancíasBicicletasPeatonesGestión: demanda, incentivos, etcOtras medidasMedidas coordinadas y planes integrales Experiencias europeasLa situación en EspañaProgramas y proyectos subvencionados Programas de la Unión EuropeaProyectos internacionales no vin...

Estudio inicial y plan maestro del proyecto de playa de "Las Calas"

OpenAIRE

Gamboa Otero, José Luis; Siucho Dextre, Julián

2016-01-01

El proyecto de desarrollo inmobiliario Las Calas se ubica en el kilómetro 180 de la carretera Panamericana Norte. Asimismo, cuenta con una extensión total de 244 ha, que enmarcan tres playas privadas (Quita Calzón, Lampay y Mirador). Cabe agregar que abarca 3.5 km de litoral y de acantilados. El proyecto se desarrollará en el transcurso de 10 años. En este lapso de tiempo, se proveerá distintos productos inmobiliarios y de uso mixto. El plan maestro consta de lotes, apartamentos, cancha ...

Proyecto de blindaje de un acelerador de electrones con finalidad de radioterapia

OpenAIRE

Jiménez Gordon, David

2010-01-01

El presente proyecto pretende dar cobertura a la reciente revisión de las normativas vigentes (DIN 6847-2, septiembre de 2008 y NCRP Report nº 151, diciembre de 2005) sobre el blindaje de instalaciones de radioterapia equipadas con acelerador lineal. En estas instalaciones el blindaje constituye prácticamente el 100% de la obra civil del proyecto. En los últimos años, en España y a nivel mundial, se ha experimentado un gran aumento de las solicitudes de autorización de este tip...

Aprendiendo a Sentir: Proyecto sobre las emociones para la Escuela El Pilar

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Ortega-Villaizán Abad, Rosa

2017-01-01

En este Trabajo de fin de grado se presenta un proyecto didáctico dirigido a fomentar, en el alumnado de P-4 de la Escuela El Pilar, las habilidades para gestionar las propias emociones y comprender las emociones de los demás. En primer lugar se revisaron los principales modelos teóricos sobre la Educación Emocional. Se analizó la legislación estatal y autonómica, y distintas metodologías para trabajar las emociones. En segundo lugar se elaboró el proyecto, que consta de 12 act...

Estudio de alternativas de almacenamiento en proyectos de análisis predictivo

OpenAIRE

Rodríguez Sevilla, Carlos

2018-01-01

Con este trabajo trataremos de contextualizar las diferencias entre los posibles métodos de almacenamiento de un proyecto de análisis predictivo. Para ello el método seguido incluye el desarrollo en R de un proyecto genérico de análisis predictivo que se utilizará como base para estudiar las consecuencias de la elección del método de almacenamiento. Como opciones se han elegido tres sistemas representando los paradigmas de almacenamiento más comunes que encontramos en la actualidad: PostgreSQ...

Edificio Roca, calle San Vicente, 32 (1934-36) Valencia: proyecto de interiorismo

OpenAIRE

CARBONELL SANTACRUZ, MARÍA DE LA LUZ

2012-01-01

Este Proyecto Final de Grado trata sobre la reutilización del Edificio Roca (1934-36), que está situado en la calle San Vicente, 32, de Valencia y es obra del arquitecto Vicente Valls Gadea (1985-1922). El proyecto se articula en tres fases. La fase inicial comienza con el estudio histórico de la ciudad de Valencia. A continuación trata de la arquitectura europea a partir de la Revolución Industrial y el movimiento arquitectónico racionalista en Valencia. Por último, se estudia la calle...

Degenerações periféricas da retina em pacientes candidatos à cirurgia refrativa Peripheral retina degeneration in patients who are candidates for refractive surgery

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Paulo Henrique de Avila Morales

2001-02-01

Full Text Available Objetivo: O objetivo desse estudo é verificar em indivíduos míopes candidatos à cirurgia refrativa a prevalência dos diferentes tipos de lesões retinianas periféricas degenerativas de acordo com o tipo de miopia. Métodos: De forma prospectiva, no período de um ano, foram examinados os olhos dos pacientes no Setor de Cirurgia Refrativa do Departamento de Oftalmologia da Universidade Federal de São Paulo - Escola Paulista de Medicina que durante a sua consulta inicial apresentassem refração com equivalente esférico superior ou igual a -1,00 dioptria esférica, e não tivessem antecedentes pessoais de doença ou cirurgia ocular no período. Foi investigada a existência de lesões e/ou degenerações periféricas predisponentes ao descolamento regmatogênico de retina. Resultados: O grupo foi composto, em sua maioria, por adultos jovens (média de idade de 31 anos. Foram observados olhos com miopia baixa (263 olhos, 31%, moderada (300 olhos, 36% e alta (277 olhos, 33%; em 35,4% dos pacientes (27% dos olhos foram encontradas degenerações periféricas, sendo o branco com e sem pressão a alteração mais freqüente (23,4% dos pacientes ou 17,5% dos olhos. Entre as lesões predisponentes ao descolamento regmatogênico da retina, a mais encontrada foi a degeneração em treliça (8,6% dos pacientes ou 6% dos olhos. Conclusões: As alterações periféricas predisponentes ou não ao descolamento regmatogênico de retina apresentaram aumento de prevalência de acordo com o aumento do grau de miopia, com exceção das roturas. Todos os pacientes com miopia alta e candidatos à cirurgia refrativa devem ter a periferia retiniana de ambos os olhos examinada.Purpose: To verify, in myopic individuals who are candidates for refractive surgery, the prevalence of different types of peripheral degenerative lesions of the retina, according to the type of myopia. Methods: Prospectively, during a one-year interval, we examined the eyes of patients in

Adaptation of the Central Retina for High Acuity Vision: Cones, the Fovea and the Avascular Zone

Science.gov (United States)

Provis, Jan M; Dubis, Adam M; Maddess, Ted; Carroll, Joseph

2013-01-01

Presence of a fovea centralis is directly linked to molecular specification of an avascular area in central retina, before the fovea (or `pit') begins to form. Modeling suggests that mechanical forces, generated within the eye, initiate formation of a pit within the avascular area, and its later remodeling in the postnatal period. Within the avascular area the retina is dominated by `midget' circuitry, in which signals are transferred from a single cone to a single bipolar cell, then a single ganglion cell. Thus in inner, central retina there are relatively few lateral connections between neurons. This renders the region adaptable to tangential forces, that translocate of ganglion cells laterally / centrifugally, to form the fovea. Optical coherence tomography enables live imaging of the retina, and shows that there is greater variation in the morphology of foveae in humans than previously thought. This variation is associated with differences in size of the avascular area and appears to be genetically based, but can be modified by environmental factors, including prematurity. Even when the fovea is absent (foveal hypoplasia), cones in central retina adopt an elongated and narrow morphology, enabling them to pack more densely to increase the sampling rate, and to act as more effective waveguides. Given these findings, what then is the adaptive advantage of a fovea? We suggest that the advantages of having a pit in central retina are relatively few, and minor, but together work to enhance acuity. PMID:23500068

Instalación domótica sobre un proyecto ICT para un edificio de viviendas residenciales

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Martínez Tàrraga, Alex

2007-01-01

La finalidad de este proyecto consiste en diseñar e implementar una instalación domótica a partir de un proyecto ICT ya realizado, en un conjunto residencial de viviendas ya construidas. El factor principal de este proyecto es mejorar el nivel de vida del usuario final, otorgándole un mayor confort dentro de su hogar, para realizar este propósito se ha diseñado una instalación con las funciones – dispositivos necesarios con capacidad de procesar audio y vídeo, comunicarse vía Internet, tel...

Stereotyped Synaptic Connectivity Is Restored during Circuit Repair in the Adult Mammalian Retina.

Science.gov (United States)

Beier, Corinne; Palanker, Daniel; Sher, Alexander

2018-06-04

Proper function of the central nervous system (CNS) depends on the specificity of synaptic connections between cells of various types. Cellular and molecular mechanisms responsible for the establishment and refinement of these connections during development are the subject of an active area of research [1-6]. However, it is unknown if the adult mammalian CNS can form new type-selective synapses following neural injury or disease. Here, we assess whether selective synaptic connections can be reestablished after circuit disruption in the adult mammalian retina. The stereotyped circuitry at the first synapse in the retina, as well as the relatively short distances new neurites must travel compared to other areas of the CNS, make the retina well suited to probing for synaptic specificity during circuit reassembly. Selective connections between short-wavelength sensitive cone photoreceptors (S-cones) and S-cone bipolar cells provides the foundation of the primordial blue-yellow vision, common to all mammals [7-18]. We take advantage of the ground squirrel retina, which has a one-to-one S-cone-to-S-cone-bipolar-cell connection, to test if this connectivity can be reestablished following local photoreceptor loss [8, 19]. We find that after in vivo selective photoreceptor ablation, deafferented S-cone bipolar cells expand their dendritic trees. The new dendrites randomly explore the proper synaptic layer, bypass medium-wavelength sensitive cone photoreceptors (M-cones), and selectively synapse with S-cones. However, non-connected dendrites are not pruned back to resemble unperturbed S-cone bipolar cells. We show, for the first time, that circuit repair in the adult mammalian retina can recreate stereotypic selective wiring. Copyright © 2018 Elsevier Ltd. All rights reserved.

Post-translational processing of synaptophysin in the rat retina is disrupted by diabetes.

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Travis S D'Cruz

Full Text Available Synaptophysin, is an abundant presynaptic protein involved in synaptic vesicle recycling and neurotransmitter release. Previous work shows that its content is significantly reduced in the rat retina by streptozotocin (STZ-diabetes. This study tested the hypothesis that STZ-diabetes alters synaptophysin protein turnover and glycosylation in the rat retina. Whole explant retinas from male Sprague-Dawley rats were used in this study. Rats were made diabetic by a single intraperitoneal STZ injection (65 mg/kg body weight in 10 mM sodium citrate, pH 4.5. mRNA translation was measured using a (35S-methionine labeling assay followed by synaptophysin immunoprecipitation and autoradiography. A pulse-chase study was used to determine the depletion of newly synthesized synaptophysin. Depletion of total synaptophysin was determined after treatment with cycloheximide. Mannose rich N-glycosylated synaptophysin was detected by treating retinal lysates with endoglycosidase H followed by immunoblot analysis. Synaptophysin mRNA translation was significantly increased after 1 month (p<0.001 and 2 months (p<0.05 of STZ-diabetes, compared to age-matched controls. Newly synthesized synaptophysin degradation was significantly accelerated in the retina after 1 and 2 months of diabetes compared to controls (p<0.05. Mannose rich glycosylated synaptophysin was significantly increased after 1 month of STZ-diabetes compared to controls (p<0.05.These data suggest that diabetes increases mRNA translation of synaptophysin in the retina, resulting in an accumulation of mannose rich glycosylated synaptophysin, a transient post-translational state of the protein. This diabetes-induced irregularity in post-translational processing could explain the accelerated degradation of retinal synaptophysin in diabetes.

Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

Science.gov (United States)

Widomska, Justyna; Zareba, Mariusz; Subczynski, Witold Karol

2016-01-01

Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene) and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin). Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls), are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases. PMID:27030822

Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

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Justyna Widomska

2016-01-01

Full Text Available Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin. Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls, are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases.

Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas - a comparative study

DEFF Research Database (Denmark)

Christiansen, Anders Tolstrup; Kiilgaard, Jens Folke; Klemp, Kristian

2018-01-01

retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY......Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including...... humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy...

Oficina de Gestión de Proyectos Ágil: Control y Seguimiento de Proyectos Ágiles

OpenAIRE

Álvarez Puertas, Luis

2013-01-01

Durante los últimos años en las organizaciones orientadas a proyectos (OOP) han concurrido una serie de tendencias, comúnmente asumidas como buenas prácticas, que sin embargo, necesitan ser personalizadas a cada organización, para que realmente actúen como palancas de cambio y mejora, y no como meros obstáculos burocráticos en el trabajo diario de las organizaciones. Estas tendencias, si bien orientadas a toda la organización a nivel corporativo, consecuentemente, tienen un alto impacto en...

Correlations between specific patterns of spontaneous activity and stimulation efficiency in degenerated retina.

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Christine Haselier

Full Text Available Retinal prostheses that are currently used to restore vision in patients suffering from retinal degeneration are not adjusted to the changes occurring during the remodeling process of the retina. Recent studies revealed abnormal rhythmic activity in the retina of genetic mouse models of retinitis pigmentosa. Here we describe this abnormal activity also in a pharmacologically-induced (MNU mouse model of retinal degeneration. To investigate how this abnormal activity affects the excitability of retinal ganglion cells, we recorded the electrical activity from whole mounted retinas of rd10 mice and MNU-treated mice using a microelectrode array system and applied biphasic current pulses of different amplitude and duration to stimulate ganglion cells electrically. We show that the electrical stimulation efficiency is strongly reduced in degenerated retinas, in particular when abnormal activity such as oscillations and rhythmic firing of bursts of action potentials can be observed. Using a prestimulus pulse sequence, we could abolish rhythmic retinal activity. Under these conditions, the stimulation efficiency was enhanced in a few cases but not in the majority of tested cells. Nevertheless, this approach supports the idea that modified stimulation protocols could help to improve the efficiency of retinal prostheses in the future.

Expression of Endoplasmic Reticulum Stress-Related Factors in the Retinas of Diabetic Rats

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Shu Yan

2012-01-01

Full Text Available Recent reports show that ER stress plays an important role in diabetic retinopathy (DR, but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ. The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP, and synoviolin(HRD1 were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.

Experiencias y limitaciones en el proyecto de intervención educativa la Quinta Dimensión (5D: El proyecto “El Club del mohán”

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Nathalia Andrea Hurtado Manrique

2018-02-01

Full Text Available La educación se ha ubicado como un tema social, económico, político y cultural importante, de preocupación tanto nacional como internacional. Por esto, se han desarrollado diversos proyectos orientados hacia el desarrollo, mejoramiento e intervención en la educación, principalmente en la escolaridad de primaria y secundaria. Uno de estos proyectos es el modelo de la Quinta Dimensión, el cual se decide adaptar en el semillero de Psicología Educativa de la Universidad Icesi denominándolo proyecto "El club del Mohán", con el objetivo principal fue generar una intervención que permitiera aportar en las demandas sociales de la Ludoteca, espacio ubicado en Siloé al que asisten muchos estudiantes para ver clases y realizar actividades extracurriculares. Este documento, de tipo reflexivo, condensa las experiencias resultantes de la adaptación del modelo la 5D, las cuales contienen limitaciones, como el conflicto que se gestaba entre los escolares, la propuesta de actividades que fueron difíciles de comprender, entre otros, así como reflexiones concretas de cada actividad.

Msx1 is expressed in retina endothelial cells at artery branching sites

OpenAIRE

Miguel Lopes; Olivier Goupille; Cécile Saint Cloment; Benoît Robert

2012-01-01

Summary Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1lacZ is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2lacZ is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the ret...

INCUBACIÓN DE PROYECTOS PARA INICIATIVAS EMPRESARIALES EN LA UNIVERSIDAD LIBRE DE CALI

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Luis Fernando Parra Villanueva

2010-12-01

Full Text Available En el trabajo se presenta una experiencia de incubación de proyectos para iniciativas empresariales que fue desarrollada a través de la gestión de proyectos de base tecnológica en la Universidad Libre de Cali, con la participación de estudiantes y profesores de la Universidad. Se formularon 18 proyectos en diferentes actividades económicas, logrando consolidar los planes de negocio e incubar un 38% y formalizar un 17%, con la expectativa de lograr la incubación total de los proyectos pues el nivel de deserción al programa es bajo y los planes de negocio demuestran su viabilidad de mercado, técnica, legal, financiera y económica. AbstractAn experience of project incubation for business initiatives is presented in the paper. That experience was developed by the management of technological based projects at Free University of Cali, with the participation of students and professors of the University. There were formulated 18 projects in different economic activities, managing to reach the business plans, to incubate a 38% and to formalize a 17%, with an expectation about the achievement of the total incubation of the projects; taking into account the low desertion level to the program and the market, technical, legal, financial an economic viability that show the business plans.

GESTIÓN DE UN PROYECTO DE I+D+i EN EL ÁREA DE NANOTECNOLOGÍA

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María Clara Guiridlian Guarino

2014-12-01

Full Text Available El proyecto tiene como objetivo general el desarrollo de cadenas de valor que se sustenten en la comercialización de productos formulados a partir de materiales de alto valor agregado basados en matrices poliméricas, mediante el agregado de NANO-ARCILLAS modificadas incluyendo las etapas de laboratorio, escala piloto y pre-comercial. En el proyecto interactúan el sector industrial, el ámbito académico y el estado a través de sus áreas de fomento al desarrollo científico tecnológico. Si bien en la etapa inicial se utilizó la metodología clásica de Gestión de Proyectos siguiendo los lineamientos del PMBOK surgió la necesidad de aplicar otra metodología complementaria para el trabajo diario. Los proyectos de I+D+i piden básicamente rapidez y calidad, pero para asumir estos retos, es necesario tener agilidad y flexibilidad. Para ello se implementó la metodología ágil SCRUM. La misma está basada en un proceso constructivo iterativo e incremental donde las iteraciones tienen duración fija pero corta que permite hacer entregas parciales que se van complementando en función del avance del proyecto. Este proyecto requiere, como otros de I+D+i, la ejecución de diversos ensayos de laboratorio cuyos resultados determinan los posteriores cursos de acción. Para ello se requería una metodología que estuviera focalizada en la realización de las tareas que integran las distintas fases de desarrollo del proyecto así como una mayor capacidad de respuesta al cambio frente al seguimiento del plan. Se encontró que aplicando esta metodología se puede responder de manera eficiente a los cambios en los productos en desarrollo y se mejoraba la previsibilidad a través de una mejor gestión del riesgo.

The Retinome – Defining a reference transcriptome of the adult mammalian retina/retinal pigment epithelium

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Goetz Thomas

2004-07-01

Full Text Available Abstract Background The mammalian retina is a valuable model system to study neuronal biology in health and disease. To obtain insight into intrinsic processes of the retina, great efforts are directed towards the identification and characterization of transcripts with functional relevance to this tissue. Results With the goal to assemble a first genome-wide reference transcriptome of the adult mammalian retina, referred to as the retinome, we have extracted 13,037 non-redundant annotated genes from nearly 500,000 published datasets on redundant retina/retinal pigment epithelium (RPE transcripts. The data were generated from 27 independent studies employing a wide range of molecular and biocomputational approaches. Comparison to known retina-/RPE-specific pathways and established retinal gene networks suggest that the reference retinome may represent up to 90% of the retinal transcripts. We show that the distribution of retinal genes along the chromosomes is not random but exhibits a higher order organization closely following the previously observed clustering of genes with increased expression. Conclusion The genome wide retinome map offers a rational basis for selecting suggestive candidate genes for hereditary as well as complex retinal diseases facilitating elaborate studies into normal and pathological pathways. To make this unique resource freely available we have built a database providing a query interface to the reference retinome 1.

Análisis retrospectivo de los proyectos de ciencia, tecnología e innovación del subsector pecuario financiados por Colciencias, 1991-2010

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Mónica María Baquero Parra

2012-12-01

Full Text Available Entre las herramientas que ofrece Colciencias para lograr sus objetivos como entidad rectora del Sistema Nacional de Ciencia, Tecnología e Innovación, se encuentran las convocatorias públicas. El objetivo del presente trabajo es identificar y analizar los proyectos financiados por Colciencias durante el periodo 1991-2010 en temáticas correspondientes al subsector pecuario. Para esto se empleó la base de datos de registro de proyectos de Colciencias, a fin de identificar los proyectos del subsector pecuario financiados desde 1991 hasta el 2010. De cada proyecto se identificó el área temática, la especie animal objeto del proyecto, el tipo de entidad ejecutora, el departamento de ejecución y el programa nacional responsable del seguimiento. Durante el periodo de interés, Colciencias financió 4839 proyectos, de los cuales 218 corresponden al subsector pecuario, siendo el 2009 el año con un mayor número de proyectos financiados (23 en este subsector. El área temática con un mayor número de proyectos financiados es acuicultura y pesca seguida de sanidad animal y sistemas de producción, con 86, 39 y 24 proyectos financiados, respectivamente. Las especies objeto del mayor número de proyectos financiados fueron las acuáticas (86 proyectos y los bovinos (80 proyectos. Las entidades ejecutoras fueron en su mayoría universidades públicas, seguidas por institutos de investigación y CENI; los departamentos de ejecución fueron Bogotá, Antioquia y Cundinamarca con 29,55, 13,64 y 13,64 %, respectivamente. Finalmente, los programas nacionales que hicieron seguimiento a un mayor número de proyectos son agropecuario, mar y recursos hidrobiológicos y biotecnología.

La retina para el médico no oftalmólogo

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Clara Leonor Varón Plata, MD

2010-01-01

Full Text Available La retina es un tejido fundamental en el órgano de la visión.En este artículo hacemos una revisión sobre la anatomía yfisiología de esta estructura así como sobre las principalespatologías que la pueden afectar, entre ellas: despren-dimiento de retina, retinopatía diabética y la enfermedadmacular relacionada con la edad. Aunque actualmentecontamos con técnicas médicas y quirúrgicas seguras yefectivas para el manejo de estas patologías, aúnrepresentan un reto para la ciencia médica, y en estadosavanzados comprometen seriamente la función visual, porello es de gran importancia que el médico general tengaclaros los conceptos básicos sobre el diagnóstico de estasenfermedades, para realizar una remisión adecuada y así poder evitar al máximo secuelas visuales en el paciente. En este artículo revisamos libros de texto reconocidos y empleando MEDLINE, algunos artículos representativos sobre este tema, para mostrar un panorama general del estado actual, clínico e investigativo, del diagnóstico y tratamientode las enfermedades más importantes que afectan la retina y el vítreo. ______________________________________________________________________The retina is a fundamental tissue of the visual organ. In this article we make a review of the anatomy and physiology of this structure as well as the main pathologies that may affect it like: retinal detachment, diabetic retinopathy, and age related macular degeneration. Although currently there are safe medical and surgical alternatives for the management of these diseases, they still represent a challenge for the medical science, and in advanced stagesthey seriously compromise visual function. For this reason it is of vital importance that the primary care physician has clear concepts about the diagnosis of these diseases, to perform an adequate referral, avoiding visual sequelae as much as possible. In this article we reviewed recognized textbooks and using MEDLINE we found some

Human cadaver retina model for retinal heating during corneal surgery with a femtosecond laser

Science.gov (United States)

Sun, Hui; Fan, Zhongwei; Yun, Jin; Zhao, Tianzhuo; Yan, Ying; Kurtz, Ron M.; Juhasz, Tibor

2014-02-01

Femtosecond lasers are widely used in everyday clinical procedures to perform minimally invasive corneal refractive surgery. The intralase femtosecond laser (AMO Corp. Santa Ana, CA) is a common example of such a laser. In the present study a numerical simulation was developed to quantify the temperature rise in the retina during femtosecond intracorneal surgery. Also, ex-vivo retinal heating due to laser irradiation was measured with an infrared thermal camera (Fluke Corp. Everett, WA) as a validation of the simulation. A computer simulation was developed using Comsol Multiphysics to calculate the temperature rise in the cadaver retina during femtosecond laser corneal surgery. The simulation showed a temperature rise of less than 0.3 degrees for realistic pulse energies for the various repetition rates. Human cadaver retinas were irradiated with a 150 kHz Intralase femtosecond laser and the temperature rise was measured withan infrared thermal camera. Thermal camera measurements are in agreement with the simulation. During routine femtosecond laser corneal surgery with normal clinical parameters, the temperature rise is well beneath the threshold for retina damage. The simulation predictions are in agreement with thermal measurements providing a level of experimental validation.

Light-modulated release of RFamide-like neuropeptides from nervus terminalis axon terminals in the retina of goldfish.

Science.gov (United States)

Fischer, A J; Stell, W K

1997-03-01

The nervus terminalis of teleosts, a cranial nerve anatomically associated with the olfactory system, projects to visual system targets including retina and optic tectum. It is known to contain gonadotropin-releasing hormone and RFamide-like peptides, but its function remains unknown. We have probed nervus terminalis function in goldfish by measuring peptide content in retina and tectum with a radioimmunoassay for A18Famide (neuropeptide AF; bovine morphine-modulating peptide). We found that retinal peptide content increased in the dark and decreased in the light, whereas tectal peptide content decreased in the dark and increased in the light. In addition, RFamide-like peptide content in the retina was transiently decreased by severing both olfactory tracts, increased in light-adapted eyes treated with a GABAergic agonist (isoguvacine), and decreased in dark-adapted eyes treated with GABAergic antagonists (bicuculline and picrotoxin). We also found that RFamide-like peptide release could be induced in dark-adapted isolated-superfused retinas by exposure to light or a high concentration (102.5 mM) of potassium ions. We interpret the increase and decrease in peptide content as reflecting a decrease and increase, respectively, in rate of peptide release. We propose that the release and accumulation of RFamide-like peptides in axon terminals of nervus terminalis processes in the retina are modulated primarily by neurons intrinsic to the retina and regulated by light. Peptide release appears to be inhibited tonically in the dark by GABA acting through GABAA receptors; light facilitates peptide release by disinhibition due to a reduction in GABA release. In addition, we propose that electrical signals originating outside the retina can override these intrinsic release-modulating influences.

Taurine biosynthesis in frog retina: effects of light and dark adaptations

International Nuclear Information System (INIS)

Nishimura, C.; Ida, S.; Kuriyama, K.

1983-01-01

The retinal uptake and metabolism of cysteine, a precursor for taurine biosynthesis, were analysed using the bull frog. The [ 14 C] cysteine uptake into isolated retina had some specific properties: It was rather temperature independent, required Na ions, was inhibited by ouabain but not by dinitrophenol, and exhibited saturation kinetics composed of two components. When retinal homogenate was incubated with 12-30 microM of L-[U- 14 C]cysteine, the accumulation of labeled alanine, cysteine sulfinic acid (CSA), cysteic acid (CA), hypotaurine, and taurine was detected. The metabolic conversions of [ 14 C] cysteine to labeled alanine, hypotaurine, and taurine were linear over 90 minutes. Prolonged light adaptation (3 weeks) induced a significant reduction in the formation of labeled CA, CSA, hypotaurine, and taurine from [ 14 C] cysteine. On the other hand, it was found that in dark-adapted retinae, the formation of labeled taurine from [ 14 C] cysteine increased significantly in spite of the reduction in the formation of labeled CA. These results indicate that biosynthetic pathways exist for taurine from cysteine in frog retina, and that these metabolic pathways are involved in the regulation of retinal taurine content under continuous visual adaptation

El proyecto pedagógico como estrategia de formación de formadores

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Abelardo Pineda Rodriguez

2014-03-01

Full Text Available Proyecto Pedagógico para la formación de docentes es una innovación nacida en 1993, precedida de corrientes nacionales e internacionales. Su estructura consta de tres ejes básicos (reflexión teórica, investigación y práctica docente que crecen simultáneamente desde el primer semestre, aplicados en tres componentes reales (la escuela, el saber pedagógico y la historia del maestro. Cada estudiante construye su proyecto personal en compañía de un asesor. Su pedagogía se arraiga en el constructivismo, activismo y aprendizaje significativo. El currículo flexible ofrece una gama de seminarios, sin prerrequisitos, que alimentan los proyectos personales. La evaluación cualitativa permanente fomenta la autoevaluación y evaluación. El informe final no es tesis de grado. La innovación impacto positivamente todos Los departamentos caribeños. Esto provoca el sueño pedagogizante futurista del articulista.

Project of renewable energy for agriculture; Proyecto de energia renovable para la agricultura

Energy Technology Data Exchange (ETDEWEB)

Montufar Avilez, Octavio [FIRCO (Mexico)

2005-07-01

The document presents a general design of the hydraulic system, a hydraulic design of cattle ranch and a hydraulic design by dripping. It also discusses the components of the energy project, which are: institutional fortification, promotion and diffusion, market development (studies), specifications and certification, investments, technical support and direction of the project. The objective of this project is to diminish ignorance in the sector, to reduce the investment costs and to obtain a long term-sustainable effect. [Spanish] En este documento se describe un diseno general del sistema hidraulico, un diseno hidraulico de ganaderia, un diseno hidraulico por goteo y los componentes del proyecto de energia que son: fortalecimiento institucional, promocion y difusion, desarrollo del mercado (estudios), especificaciones y certificacion, inversiones, asistencia tecnica y direccion del proyecto. El objetivo de este proyecto es minimizar el desconocimiento en el sector, reducir los costos de inversion y que el efecto sea sostenible a largo plazo.

Proyectos educativos: estudio comparativo entre Venezuela y Colombia

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Mineira Finol

2005-09-01

Full Text Available El Proyecto Educativo Integral Comunitario (PEIC y el Proyecto Educativo Institucional constituyen la categoría de comparación entre Venezuela y Colombia; a tal fin, este estudio de tipo comparativo-documental se centró en determinar congruencias y discrepancias entre PEIC y PEI, utilizando el método comparativo estructurado en cuatro fases: descripción, interpretación, yuxtaposición y comparación, propuesto por Hilker y Bereday (1972 Entre los resultados se tienen: congruencias en cuanto surgen sobre las bases de diagnóstico externos efectuados por organismos internacionales UNESCO, CEPAL ante la inefectividad y baja productividad de ambos países; a nivel interno responden a políticas educativas reformadoras de currículum y leyes,. Discrepancias referidas al tiempo de implementación; en Venezuela a partir de 1996; Colombia en 1992; este último, consolidó las bases para la participación a través del gobierno escolar y de un sistema de evaluación institucional, muy incipiente en Venezuela.

Simple Experiments on the Physics of Vision: The Retina

Science.gov (United States)

Cortel, Adolf

2005-01-01

Many simple experiments can be performed in the classroom to explore the physics of vision. Students can learn of the two types of receptive cells (rods and cones), their distribution on the retina and the existence of the blind spot.

Distribution of [35S] taurine in mouse retina after intravitreal and intravascular injection

International Nuclear Information System (INIS)

Pourcho, R.G.

1977-01-01

The distribution of [ 35 S] taurine in mouse retinae was studied by autoradiographic techniques after either intravitreal or intravascular injection. The route of injection did not affect the final localization. The major sites of label accumulation were the outer nuclear layer, the inner nuclear layer, and Mueller cell processes adjacent to the vitreal surface. The distribution was consistent with the interpretation that taurine was localized within two cellular compartments of mouse retina, photoreceptor cells and Mueller cells. (author)

Proyecto de atención preventiva de mujeres con alto riesgo reproductivo

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A. Cardona Pérez

2017-06-01

El proyecto es una estrategia de mejora en la atención médica de las mujeres en edad reproductiva con enfermedades crónicas o sistémicas, que contempla dos direcciones fundamentales: 1 mejora de los servicios de salud, 2 mejora de la salud de la población. La implementación de este proyecto pretende contribuir en la reducción de la mortalidad materna por causa indirecta, y a través de esta estrategia reducir las brechas existentes en las condiciones de salud entre la población de nuestro país.

Proyecto de ejecución de una nave para almacenamiento de cereales

OpenAIRE

Ramón Jiménez, Beatriz

2013-01-01

TRABAJO RECOMENDADO POR EL CENTRO El proyecto tiene por objeto sentar las bases técnicas para la ejecución de una nave o edificio que se destinará para el almacenaje de cereal, con una superficie construida de 1815 m² y superficie útil 1731 m², para lo cual se dispone de suficiente superficie en concreto en la calle San José Obrero, parcela 1, ubicada en el término municipal de El Burgo de Osma - Ciudad de Osma (Soria) donde se llevará a cabo el proyecto. La construcción de ...

Testbeam results of the first real-time embedded tracking system with artificial retina

Energy Technology Data Exchange (ETDEWEB)

Neri, N., E-mail: nicola.neri@mi.infn.it; Abba, A.; Caponio, F.; Citterio, M.; Coelli, S.; Fu, J.; Merli, A.; Monti, M.; Petruzzo, M.

2017-02-11

We present the testbeam results of the first real-time embedded tracking system based on artificial retina algorithm. The tracking system prototype is capable of fast track reconstruction with a latency of the response below 1 μs and track parameter resolutions that are comparable with the offline results. The artificial retina algorithm was implemented in hardware in a custom data acquisition board based on commercial FPGA. The system was tested successfully using a 180 GeV/c proton beam at the CERN SPS with a maximum track rate of about 280 kHz. Online track parameters were found in good agreement with offline results and with the simulated response. - Highlights: • First real-time tracking system based on artificial retina algorithm tested on beam. • Fast track reconstruction within one microsecond latency and offline like quality. • Fast tracking algorithm implemented in commercial FPGAs.

Adaptive optics parallel spectral domain optical coherence tomography for imaging the living retina

Science.gov (United States)

Zhang, Yan; Rha, Jungtae; Jonnal, Ravi S.; Miller, Donald T.

2005-06-01

Although optical coherence tomography (OCT) can axially resolve and detect reflections from individual cells, there are no reports of imaging cells in the living human retina using OCT. To supplement the axial resolution and sensitivity of OCT with the necessary lateral resolution and speed, we developed a novel spectral domain OCT (SD-OCT) camera based on a free-space parallel illumination architecture and equipped with adaptive optics (AO). Conventional flood illumination, also with AO, was integrated into the camera and provided confirmation of the focus position in the retina with an accuracy of ±10.3 μm. Short bursts of narrow B-scans (100x560 μm) of the living retina were subsequently acquired at 500 Hz during dynamic compensation (up to 14 Hz) that successfully corrected the most significant ocular aberrations across a dilated 6 mm pupil. Camera sensitivity (up to 94 dB) was sufficient for observing reflections from essentially all neural layers of the retina. Signal-to-noise of the detected reflection from the photoreceptor layer was highly sensitive to the level of cular aberrations and defocus with changes of 11.4 and 13.1 dB (single pass) observed when the ocular aberrations (astigmatism, 3rd order and higher) were corrected and when the focus was shifted by 200 μm (0.54 diopters) in the retina, respectively. The 3D resolution of the B-scans (3.0x3.0x5.7 μm) is the highest reported to date in the living human eye and was sufficient to observe the interface between the inner and outer segments of individual photoreceptor cells, resolved in both lateral and axial dimensions. However, high contrast speckle, which is intrinsic to OCT, was present throughout the AO parallel SD-OCT B-scans and obstructed correlating retinal reflections to cell-sized retinal structures.

Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice.

Science.gov (United States)

Wang, Yanhe; Yin, Zhiyuan; Gao, Lixiong; Sun, Dayu; Hu, Xisu; Xue, Langyue; Dai, Jiaman; Zeng, YuXiao; Chen, Siyu; Pan, Boju; Chen, Min; Xie, Jing; Xu, Haiwei

2017-01-01

Retinitis pigmentosa (RP) is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1) mice. The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP. © 2017 The Author(s). Published by S. Karger AG, Basel.

Análisis de los proyectos del sector agropecuario financiados por Colciencias durante el año 2010

OpenAIRE

Suárez O, Edison; Baquero P, Mónica

2013-01-01

RESUMENObjetivo. Analizar los proyectos del sector agropecuario financiados por Colciencias durante el año 2010. Materiales y métodos. Se utilizó la base de datos de registro de proyectos correspondientes al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuarias para identificar las propuestas presentadas, elegibles y financiadas de las convocatorias del año 2010. Los proyectos se clasificaron con base en la nomenclatura Internacional de la UNESCO para los campos de la ciencia y ...

Avaliação ocular multimodal em doenças heredodistróficas e degenerativas da retina Multimodal fundus imaging in heredodystrophic and degenerative diseases of the retina

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Daniela Cavalcanti Ferrara

2009-10-01

Full Text Available A tomografia de coerência óptica incorporou-se gradativamente ao contemporâneo arsenal diagnóstico em Oftalmologia, passando a exercer papel fundamental na investigação e condução de doenças oculares, particularmente na especialidade de Retina e Vítreo. A disponibilização comercial da nova geração de aparelhos, chamada de tomografia de coerência óptica "espectral", baseada em conceito físico distinto que permite a aquisição de imagens em alta velocidade, marcou o início de uma nova era desta tecnologia de investigação auxiliar. Adicionalmente, sua recente combinação com o oftalmoscópio de varredura a laser confocal (confocal scanning laser ophthalmoscope vem propiciando a aquisição de imagens tomográficas guiadas em tempo real pelos diferentes modos de imagem (autofluorescência de fundo, reflectância com luz "infravermelha" e angiografia com fluoresceína ou indocianina verde. A avaliação ocular multimodal (multimodal fundus imaging permite a correlação real e minuciosa de achados da morfologia retiniana e do epitélio pigmentar com dados de estudos angiográficos e de autofluorescência ou reflectância, propiciando assim inferências valiosas sobre a fisiologia do tecido. Neste artigo, discutimos brevemente as possíveis implicações da avaliação ocular multimodal na prática da especialidade de Retina e Vítreo.Optical coherence tomography was progressively incorporated to the contemporary diagnostic arsenal in Ophthalmology, playing a crucial role in the diagnosis and management of eye diseases, particularly in the specialty of retina and vitreous. The commercial availability of the new generation of devices, coined "spectral" optical coherence tomography, which is based in a distinct physical concept that permits high-speed image acquisition, launched a new era for this investigative ancillary tool. In addition, the recent combination of this new technology with a confocal scanning laser ophthalmoscope

A biochemical basis for induction of retina regeneration by antioxidants.

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Echeverri-Ruiz, Nancy; Haynes, Tracy; Landers, Joseph; Woods, Justin; Gemma, Michael J; Hughes, Michael; Del Rio-Tsonis, Katia

2018-01-15

The use of antioxidants in tissue regeneration has been studied, but their mechanism of action is not well understood. Here, we analyze the role of the antioxidant N-acetylcysteine (NAC) in retina regeneration. Embryonic chicks are able to regenerate their retina after its complete removal from retinal stem/progenitor cells present in the ciliary margin (CM) of the eye only if a source of exogenous factors, such as FGF2, is present. This study shows that NAC modifies the redox status of the CM, initiates self-renewal of the stem/progenitor cells, and induces regeneration in the absence of FGF2. NAC works as an antioxidant by scavenging free radicals either independently or through the synthesis of glutathione (GSH), and/or by reducing oxidized proteins through a thiol disulfide exchange activity. We dissected the mechanism used by NAC to induce regeneration through the use of inhibitors of GSH synthesis and the use of other antioxidants with different biochemical structures and modes of action, and found that NAC induces regeneration through its thiol disulfide exchange activity. Thus, our results provide, for the first time, a biochemical basis for induction of retina regeneration. Furthermore, NAC induction was independent of FGF receptor signaling, but dependent on the MAPK (pErk1/2) pathway. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Light pollution: the possible consequences of excessive illumination on retina.

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Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

2016-02-01

Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.

Degenerações periféricas da retina do olho míope X LASIK

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Nassaralla Jr. João J.

2004-01-01

Full Text Available O objetivo deste artigo é apresentar as degenerações periféricas mais comuns na retina dos olhos míopes, discutindo aquelas que oferecem maiores riscos para o descolamento regmatogênico da retina, seu relacionamento com a cirurgia de LASIK e a indicação para o tratamento profilático.

Alterations in energy metabolism, neuroprotection and visual signal transduction in the retina of Parkinsonian, MPTP-treated monkeys.

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Laura Campello

Full Text Available Parkinson disease is mainly characterized by the degeneration of dopaminergic neurons in the central nervous system, including the retina. Different interrelated molecular mechanisms underlying Parkinson disease-associated neuronal death have been put forward in the brain, including oxidative stress and mitochondrial dysfunction. Systemic injection of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP to monkeys elicits the appearance of a parkinsonian syndrome, including morphological and functional impairments in the retina. However, the intracellular events leading to derangement of dopaminergic and other retinal neurons in MPTP-treated animal models have not been so far investigated. Here we have used a comparative proteomics approach to identify proteins differentially expressed in the retina of MPTP-treated monkeys. Proteins were solubilized from the neural retinas of control and MPTP-treated animals, labelled separately with two different cyanine fluorophores and run pairwise on 2D DIGE gels. Out of >700 protein spots resolved and quantified, 36 were found to exhibit statistically significant differences in their expression levels, of at least ± 1.4-fold, in the parkinsonian monkey retina compared with controls. Most of these spots were excised from preparative 2D gels, trypsinized and subjected to MALDI-TOF MS and LC-MS/MS analyses. Data obtained were used for protein sequence database interrogation, and 15 different proteins were successfully identified, of which 13 were underexpressed and 2 overexpressed. These proteins were involved in key cellular functional pathways such as glycolysis and mitochondrial electron transport, neuronal protection against stress and survival, and phototransduction processes. These functional categories underscore that alterations in energy metabolism, neuroprotective mechanisms and signal transduction are involved in MPTP-induced neuronal degeneration in the retina, in similarity to

Diseño de una oficina de dirección de proyectos (PMO) para la empresa OILEC

OpenAIRE

Quishpe Fuertes, Santiago Stalin

2017-01-01

El presente trabajo está enfocado a diseñar una oficina de dirección de proyectos (PMO) para la empresa OILEC, la misma que tendrá el propósito de convertirse en un área estratégica para la organización en lo que respecta a la dirección de proyectos. La empresa se desenvuelve dentro de mercado altamente competitivo, como son los sectores de energía, minería e hidrocarburos, en donde el desarrollo de proyectos requiere del cumplimiento de exigentes estándares y una planificación exhaustiva, ta...

Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye.

Science.gov (United States)

Sharma, Robin; Williams, David R; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J

2016-02-01

Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.

Effect of high-intensity irradiation from dental photopolymerization on the isolated and superfused vertebrate retina.

Science.gov (United States)

Rassaei, Mohammad; Thelen, Martin; Abumuaileq, Ramzi; Hescheler, Jürgen; Lüke, Matthias; Schneider, Toni

2013-03-01

Light or electromagnetic radiation may damage the neurosensory retina during irradiation of photopolymerizing resinous materials. Direct and indirect effects of irradiation emitted from polymerisation curing light may represent a severe risk factor for the eyes and the skin of the lamp operators, as well as for the patient's oral mucosa. Bovine superfused retinas were used to record their light-evoked electroretinogram (ERG) as ex vivo ERGs. Both the a- and the b-waves were used as indicators for retinal damage on the functional level. The isolated retinas were routinely superfused with a standard nutrient solution under normoglycemic conditions (5 mM D-glucose). The change in the a- and b-wave amplitude and implicit time, caused by low and high intensity irradiation, was calculated and followed over time. From the results, it can be deduced that the irradiation from LED high-power lamps affects severely the normal physiological function of the bovine retina. Irradiations of 1,200 lx irreversibly damaged the physiological response. In part, this may be reversible at lower intensities, but curing without using the appropriate filter will bleach the retinal rhodopsin to a large extent within 20 to 40 s of standard application times. Constant exposure to intense ambient irradiation affects phototransduction (a-wave) as well as transretinal signalling. The proper use of the UV- and blue-light filtering device is highly recommended, and may prevent acute and long lasting damage of the neurosensory retina.

costo del capital y evaluación de proyectos en latinoamérica: una clarificación

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Sergio Zúñiga-Jara

2011-09-01

Full Text Available El estudio incluye una introducción, en la que se definen el modelo y los supuestos básicos. a partir de estos se obtiene una serie de resultados aplicables en la valoración de empresas, con implicancias en la evaluación de proyectos. el trabajo concluye con una ilustración numérica. los autores sostienen que resultados conocidos de la teoría de la estructura óptima de capital, pueden ser adaptados y aplicados en la evaluación de proyectos. esto permite aclarar aspectos clave de la evaluación privada de proyectos sobre los cuales en latinoamérica parece existir alguna confusión. Un primer resultado es que el valor actual neto (van es en realidad un concepto muy preciso y concreto, aun cuando el proyecto haya sido financiado con una mezcla de deuda y patrimonio. Un segundo resultado es que el van puede ser formulado de varias formas equivalentes, en el sentido de que su cálculo final es idéntico. Finalmente, se muestra que el punto de vista usado en la evaluación de proyectos no es relevante para estimar el van.

Análisis de los proyectos del sector agropecuario financiados por Colciencias durante el año 2010

OpenAIRE

Edison Suárez O.; Mónica Baquero P.

2013-01-01

Objetivo. Analizar los proyectos del sector agropecuario financiados por Colciencias durante el año 2010. Materiales y métodos. Se utilizó la base de datos de registro de proyectos correspondientes al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuarias para identificar las propuestas presentadas, elegibles y financiadas de las convocatorias del año 2010. Los proyectos se clasificaron con base en la nomenclatura Internacional de la UNESCO para los campos de la ciencia y la tecn...

Avian cone photoreceptors tile the retina as five independent, self-organizing mosaics.

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Yoseph A Kram

2010-02-01

Full Text Available The avian retina possesses one of the most sophisticated cone photoreceptor systems among vertebrates. Birds have five types of cones including four single cones, which support tetrachromatic color vision and a double cone, which is thought to mediate achromatic motion perception. Despite this richness, very little is known about the spatial organization of avian cones and its adaptive significance. Here we show that the five cone types of the chicken independently tile the retina as highly ordered mosaics with a characteristic spacing between cones of the same type. Measures of topological order indicate that double cones are more highly ordered than single cones, possibly reflecting their posited role in motion detection. Although cones show spacing interactions that are cell type-specific, all cone types use the same density-dependent yardstick to measure intercone distance. We propose a simple developmental model that can account for these observations. We also show that a single parameter, the global regularity index, defines the regularity of all five cone mosaics. Lastly, we demonstrate similar cone distributions in three additional avian species, suggesting that these patterning principles are universal among birds. Since regular photoreceptor spacing is critical for uniform sampling of visual space, the cone mosaics of the avian retina represent an elegant example of the emergence of adaptive global patterning secondary to simple local interactions between individual photoreceptors. Our results indicate that the evolutionary pressures that gave rise to the avian retina's various adaptations for enhanced color discrimination also acted to fine-tune its spatial sampling of color and luminance.

In vivo two-photon imaging of retina in rabbits and rats.

Science.gov (United States)

Jayabalan, Gopal Swamy; Wu, Yi-Kai; Bille, Josef F; Kim, Samuel; Mao, Xiao Wen; Gimbel, Howard V; Rauser, Michael E; Fan, Joseph T

2018-01-01

The purpose of this study was to evaluate the retina using near-infrared (NIR) two-photon scanning laser ophthalmoscopy. New Zealand white rabbits, albino rats, and brown Norway rats were used in this study. An autofluorescence image of the retina, including the retinal cells and its associated vasculatures was obtained by a real-time scan using the ophthalmoscope. Furthermore, the retinal vessels, nerve fiber layers and the non-pigmented retina were recorded with two-photon fluorescein angiography (FA); and the choroidal vasculatures were recorded using two-photon indocyanine green angiography (ICGA). Two-photon ICGA was achieved by exciting a second singlet state at ∼398 nm. Simultaneous two-photon FA and two-photon ICGA were performed to characterize the retinal and choroidal vessels with a single injection. The minimum laser power threshold required to elicit two-photon fluorescence was determined. The two-photon ophthalmoscope could serve as a promising tool to detect and monitor the disease progression in animal models. Moreover, these high-resolution images of retinal and choroidal vessels can be acquired in a real-time scan with a single light source, requiring no additional filters for FA or ICGA. The combination of FA and ICGA using the two-photon ophthalmoscope will help researchers to characterize the retinal diseases in animal models, and also to classify the types (classic, occult or mixed) of choroidal neovascularization (CNV) in macular degeneration. Furthermore, the prototype can be adapted to image the retina of rodents and rabbits. Copyright © 2017 Elsevier Ltd. All rights reserved.

Proyecto de radio online para Nájera y comarca: ‘’Ribera del Najerilla’’

OpenAIRE

Aranzubía Lumbreras, Guillermo

2013-01-01

El objetivo de este proyecto es el diseño de un programa de radio online que de forma pionera va a buscar abarcar en Nájera, como núcleo del proyecto y sus pueblos más cercanos, toda la actualidad informativa que acontezca. Queremos centrarnos en el día a día de nuestros ciudadanos, que ellos sean los protagonistas

Tendencias de proyectos de investigación en psicología clínica en Colombia

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César Armando Rey Anacona

2012-01-01

Full Text Available Se examinaron las tendencias de 195 proyectos de investigación de 22 grupos e instituciones vinculados al Nodo Temático de Psicología Clínica, de la Red de Investigadores de Psicología, los cuales se analizaron por medio de cinco categorías deductivas referentes a temas de interés de la psicología clínica. La información se recuperó del sistema de información Scienti de Colciencias en enero de 2011. El número de proyectos por categoría mostró que los temas que generaron mayor atención entre estos proyectos fueron: a La psicoterapia, b la psicopatología y la conducta anormal y c el diagnóstico y la evaluación psicológica, siendo el enfoque teórico y la formación del psicólogo los tópicos que aparentemente despertaron menos interés investigativo. Se discuten otras orientaciones encontradas en los proyectos.

Heterogeneous transgene expression in the retinas of the TH-RFP, TH-Cre, TH-BAC-Cre and DAT-Cre mouse lines.

Science.gov (United States)

Vuong, H E; Pérez de Sevilla Müller, L; Hardi, C N; McMahon, D G; Brecha, N C

2015-10-29

Transgenic mouse lines are essential tools for understanding the connectivity, physiology and function of neuronal circuits, including those in the retina. This report compares transgene expression in the retina of a tyrosine hydroxylase (TH)-red fluorescent protein (RFP) mouse line with three catecholamine-related Cre recombinase mouse lines [TH-bacterial artificial chromosome (BAC)-, TH-, and dopamine transporter (DAT)-Cre] that were crossed with a ROSA26-tdTomato reporter line. Retinas were evaluated and immunostained with commonly used antibodies including those directed to TH, GABA and glycine to characterize the RFP or tdTomato fluorescent-labeled amacrine cells, and an antibody directed to RNA-binding protein with multiple splicing to identify ganglion cells. In TH-RFP retinas, types 1 and 2 dopamine (DA) amacrine cells were identified by their characteristic cellular morphology and type 1 DA cells by their expression of TH immunoreactivity. In the TH-BAC-, TH-, and DAT-tdTomato retinas, less than 1%, ∼ 6%, and 0%, respectively, of the fluorescent cells were the expected type 1 DA amacrine cells. Instead, in the TH-BAC-tdTomato retinas, fluorescently labeled AII amacrine cells were predominant, with some medium diameter ganglion cells. In TH-tdTomato retinas, fluorescence was in multiple neurochemical amacrine cell types, including four types of polyaxonal amacrine cells. In DAT-tdTomato retinas, fluorescence was in GABA immunoreactive amacrine cells, including two types of bistratified and two types of monostratified amacrine cells. Although each of the Cre lines was generated with the intent to specifically label DA cells, our findings show a cellular diversity in Cre expression in the adult retina and indicate the importance of careful characterization of transgene labeling patterns. These mouse lines with their distinctive cellular labeling patterns will be useful tools for future studies of retinal function and visual processing. Published by Elsevier

CHANGES IN NEUROTRANSMITTER GENE EXPRESSION IN THE AGING RETINA.

Science.gov (United States)

To understand mechanisms of neurotoxicity in susceptible populations, we examined age-related changes in constitutive gene expression in the retinas of young (4mos), middle-aged (11 mos) and aged (23 mos) male Long Evans rats. Derived from a pouch of the forebrain during develop...

Parejas en el espacio transnacional: Los proyectos de mujeres que emigran por motivos conyugales

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Yolanda Bodoque Puerta

2010-01-01

Full Text Available Partiendo de una investigación sobre la migración de mujeres a través de una relación sentimental con hombres españoles, se presentan algunos resultados parciales con el objetivo de mostrar una realidad migratoria singular que también puede ser abordada desde la perspectiva transnacional. Se trata de mujeres que salen de su país para llevar a cabo un proyecto migratorio con el fin de formar una familia en el país de destino. Este proyecto, personal e individualizado, por lo general no se vincula a la existencia de redes migratorias de soporte familiar o comunitario. La transnacionalidad de estas mujeres se caracteriza por una incorporación dependiente al país de destino y la negación de su condición migrante, que comporta la ausencia de un proyecto de retorno.

Content Analysis Schedule for Bilingual Education Programs: Proyecto PAL.

Science.gov (United States)

Gonzalez, Castor

This content analysis schedule for "Proyecto PAL" in San Jose, California, presents information on the history, funding, and scope of the project. Included are sociolinguistic process variables such as the native and dominant languages of students and their interaction. Information is provided on staff selection and the linguistic…

The effects of microwave radiation on rabbit's retina

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Mohammad R. Talebnejad

2018-03-01

Conclusions: Histopathologically, cell phone simulated MW irradiation had no significant detrimental effect on the retina. However, ciliary body congestion was observed in greater fraction of those who received higher MW doses. Although there was no significant difference between post-treatment mean ERG values, there were statistically non-significant trends toward greater changes in the MW irradiated eyes.

Un acercamiento al concepto de representación: el caso de las mujeres políticas en el estado de Chihuahua

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Martha Estela Pérez

2013-01-01

Full Text Available En este documento se reflexiona sobre el fenómeno de la representación simbólica y política de las mujeres en el estado de Chihuahua. Este caso se centra en la escasa representación del sexo femenino en la política institucional y, de igual forma, se hace un acercamiento a los esquemas culturales que siguen vigentes en la esfera pública, los cuales no sólo inciden en el quehacer político femenino y masculino, sino que también conllevan a generar espacios de discriminación e inequidad y obstaculizan el empoderamiento femenino.

El horizonte temporal en el proyecto de restauración

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Angela Squassina

2016-12-01

Full Text Available La distancia existente entre el tiempo filosófico y los diversos condicionantes teóricos o prácticos que rodean a la restauración sirve como excusa para este texto de reflexión sobre el papel determinante de la percepción del tiempo para una ampliación del concepto contemporáneo de monumento, entendido como documento de múltiples lecturas que invita a renovar continuamente la experiencia de su fruición. Asumir el tiempo como una peculiar dimensión de la obra, involucrando también los conceptos asociados de integridad y de degradación, induce a introducir intencionalmente el horizonte temporal en el proyecto de restauración, reforzando la idea del proyecto de intervención como un acto de interpretación siempre abierto.

Morphological characterization and topographic analysis of multiple photoreceptor types in the retinae of mesopelagic hatchetfishes with tubular eyes

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Lauren Michelle Biagioni

2016-03-01

Full Text Available Marine hatchetfishes, Argyropelecus spp., are one of the 14 genera of mesopelagic teleosts, which possess tubular eyes. The tubular eyes are positioned dorsally on the head and consist of a main retina, which subtends a large dorsal binocular field, and an accessory retina, which subtends the lateral monocular visual field. The topographic distribution of photoreceptors in the retina of Argyropelecus sladeni, A. affinis and A. aculeatus was determined using a random, unbiased and systematic stereological approach, which consistently revealed a region of high density (area centralis in the central region of the main retina (up to a peak of 96,000 receptors per mm2 and a relatively homogeneous density of photoreceptors in the accessory retina (of approximately 20,000 receptors per mm2. The position of the area centralis in the main retina indicates this retinal region subserves greater spatial resolution in the centre of the dorsal binocular visual field. Light microscopy and transmission electron microscopy also revealed the presence of multiple photoreceptor types (two rod-like and one cone-like based on the size and shape of the inner and outer segments and ultrastructural differences in the ellipsoidal region. The presence of multiple photoreceptor types in these tubular-eyed, mesopelagic hatchetfishes may reflect the need for the visual system to function under different lighting conditions during vertical migratory behavior, especially given their unique dorsally-facing eyes.

Cmin - herramienta case basada en crisp-dm para el soporte de proyectos de minería de datos

OpenAIRE

Cobos, Carlos; Zuñiga, Jhon; Guarin, Juan; León, Elizabeth; Mendoza, Martha

2010-01-01

En este artículo se presenta la CMIN, una herramienta CASE (Computer Aided Software Engineering) integrada (que soporta todas las fases de un proceso) basada en CRISP-DM 1.0 (Cross – Industry Standard Process for Data Mining) para soportar el desarrollo de proyectos de minería de datos.Primero se expone la funcionalidad general de CMIN, lo que incluye la gestión de procesos, plantillas y proyectos, y se destaca la capacidad de CMIN para realizar el seguimiento de los proyectos de una forma fá...

Lattice degeneration of the retina.

Science.gov (United States)

Byer, N E

1979-01-01

Lattice degeneration of the retina is the most important of all clinically distinct entities that effect the peripheral fundus and are related to retinal detachment. The purpose of this review is to survey the extensive literature, to evaluate the many diverse opinions on this subject, and to correlate and summarize all the known facts regarding this disease entity. The disease is fully defined and described, both clinically and histologically. Some aspects of the disease are still poorly understood, and some remain controversial, especially in the area of management. For this reason, the indications for treatment are discussed under eight subsections, with a view toward providing practical guidelines for recommendations in management.

Proceso de Conceptualización del Entendimiento del Negocio para Proyectos de Explotación de Información

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Federico Carlos Peralta

2014-10-01

Full Text Available La disponibilidad y análisis de la información son esenciales para garantizar la correcta toma de decisiones. Debido al excesivo volumen de datos de una organización, resulta imprescindible estructurar y categorizar la masa de información que debe ser relevada para alcanzar la comprensión del negocio. Es fundamental identificar la información crítica para el negocio y obtener la misma desde el comienzo del proyecto de manera sistemática y articulada. En base a la información relevada, el responsable del proyecto podrá realizar estimaciones válidas y gestionar correctamente cada una de las tareas y actividades del proyecto. Cualquier proyecto de software puede fracasar como consecuencia de un entendimiento incorrecto del negocio, lo cual puede tener un fuerte impacto en la operación del negocio respectivo. En este contexto, se propone la construcción de un proceso de conceptualización del entendimiento del negocio para proyectos de Explotación de Información.

CREACIÓN DEL ALGORITMO HEURÍSTICO PARA LA PLANIFICACIÓN Y PROGRAMACIÓN DE CARTERAS DE PROYECTOS CON RECURSOS LIMITADOS

Directory of Open Access Journals (Sweden)

Mª Antonia Simón Rodríguez

2014-12-01

Full Text Available Existen numerosas empresas que tienen implantada una Oficina de Proyectos y los gestionan de manera unificada. Uno de los principales problemas que se encuentran es la asignación de los recursos humanos a los proyectos de cara a cumplir con los plazos establecidos. El objetivo del presente artículo es crear un nuevo algoritmo heurístico que logre resolverlo en un entorno dinámico, que tenga en cuenta las incidencias que van sucediendo, buscando el cumplimiento de hitos intermedios, dando continuidad a los recursos en un mismo proyecto y asignando distintas prioridades. Se ha realizado un estudio de la literatura referente al entorno multiproyecto y para el caso particular de carteras de proyectos. El algoritmo resultante logra satisfacer los objetivos propuestos con gran eficacia y eficiencia, logrando cumplir el plazo para todos los proyectos con prioridad crítica, respetar las fechas intermedias y logrando la nivelación de los recursos humanos disponibles.

Potassium-stimulated release of radiolabelled taurine and glycine from the isolated rat retina

Energy Technology Data Exchange (ETDEWEB)

Smith, L.F.; Pycock, C.J.

1982-09-01

The release of preloaded (/sup 3/H)glycine and (/sup 3/H)taurine in response to a depolarising stimulus (12.5-50 mM KCl) has been studied in the superfused rat retina. High external potassium concentration immediately increased the spontaneous efflux of (/sup 3/H)glycine, the effect of 50 mM K+ apparently being abolished by omitting calcium from the superfusing medium. In contrast, although high potassium concentrations increased the spontaneous efflux of (/sup 3/H)taurine from the superfused rat retina, this release was not evident until the depolarising stimulus was removed from the superfusing medium. The magnitude of this late release of (/sup 3/H)taurine was dependent on external K+ concentrations, and appeared immediately after cessation of the stimulus irrespective of whether it was applied for 4, 8, or 12 min. Potassium (50 mM)-induced release of taurine appeared partially calcium-dependent, being significantly reduced (p less than 0.01) but not abolished by replacing calcium with 1 mM EDTA in the superfusate. High-affinity uptake systems for both (/sup 3/H)glycine and (/sup 3/H)taurine were demonstrated in the rat retina in vitro (Km values, 1.67 microM and 2.97 microM; Vmax values, 19.3 and 23.1 nmol/g wet weight tissue/h, respectively). The results are discussed with respect to the possible neurotransmitter roles of both amino acids in the rat retina.

Base de datos histórica dentro del ámbito de la gestión de proyectos

OpenAIRE

Monge Arroyo, Ramon

2012-01-01

Trabajo de fin de carrera sobre una base de datos histórica de proyectos informáticos para la gestión de proyectos. Treball de fi de carrera sobre una base de dades històrica de projectes informàtics per a la gestió de projectes.

Proyecto integral Marina del Sol S.A.

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Alfredo Palacios Barra

2008-11-01

Full Text Available El megaproyecto Marina del Sol del Gran Concepción, se emplaza en el sector del canal Ifarle a espaldas del Aeropuerto Carriel Sur en la comuna de Talcahuano. Recientemente entró a funcionar el Casino Marina del Sol, el que está inscrito en el marco de los 15 proyectos autorizados en el 2006 por la Superintendencia de Juego que buscan promover el desarrollo de este sector a nivel del país.

Atrévete a innovar. Recetas para diseñar proyectos de innovación docente

OpenAIRE

Pérez Sancho, Carlota; Fernández Díaz, Elia; Martínez De la Muela, Alicia

2014-01-01

Portada e índice del manual de ayuda para comprender con detalle en qué consisten y cómo se elaboran los proyectos de innovación y mejora docente. Portada e índice del manual de ayuda para comprender con detalle en qué consisten y cómo se elaboran los proyectos de innovación y mejora docente.

Diagnostic classification of retinal degenerative diseases São Paulo and Vale Retina groups

OpenAIRE

Unonius, Nichard; Farah, Michel Eid; Sallum, Juliana M. Ferraz

2003-01-01

OBJETIVO:Organizar um banco de dados regional de todos os indivíduos portadores de doenças degenerativas da retina, com o objetivo de classificar cada paciente de acordo com o tipo de distrofia e padrão de herança. MÉTODOS: Durante o encontro do Grupo Retina São Paulo no dia 5 de maio de 2001, duzentas e quarenta e três pessoas foram registradas, sendo que parte forneceu dados de antecedentes oculares, pessoais e familiares e árvore genealógica. Noventa e três pacientes foram questionados qua...

Eye Controlled Simulation of Scotoma Effects on the Retina

Science.gov (United States)

1990-07-01

movements since the central region of the viewing. The PRLs were positioned near the retina, the macula , and its center, the fovea, have scotoma boundary...scotoma area; as macular degeneration increases in size. near to the fovea as possible to maximize acuity, Feedback of failures to detect targets might

Objetos de Aprendizaje para la cátedra de Proyecto I

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Rosanigo, Zulema Beatriz

2010-01-01

Full Text Available Proyecto I es una asignatura de la carrera de Ingeniería Civil que trata sobre el desarrollo de proyecto edilicio, componentes y detalles constructivos y diseño de instalaciones. La problemática constructiva, su desarrollo y aplicación real, es compleja y para una cabal comprensión se requiere de vivencias y experimentación. Las visitas a obra son un recurso didáctico muy valioso pero no siempre es posible de realizar. En este contexto, la generación de un espacio virtual, y la utilización de material de apoyo, lo más real posible, compuesto por videos y fotografías seriadas donde el alumno puede ver y reconocer la forma de realización de cada actividad y los materiales empleados en ella, es una forma de cubrir esa falencia y también de complementarla. Con el fin de compartir los recursos generados y maximizar el número de situaciones educativas en las que pueda ser utilizado, nos hemos propuesto plantearlos como Objetos de Aprendizaje. En este artículo se presenta el marco teórico de los objetos de aprendizaje, se describen las estrategias didácticas adoptadas en la cátedra de Proyecto I y finalmente describe cómo crear el material educativo y convertirlo en objeto de aprendizaje.

Análisis de los proyectos de investigación de financiación pública en Psicología del Deporte

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Aurelio Olmedilla

2013-10-01

Full Text Available El objetivo del presente estudio fue analizar los Proyectos de Investigación I+D+i financiados por el Plan Nacional en el área de gestión de Psicología y en el área de gestión de Deporte, así como los concedidos por el Consejo Superior de Deportes. Para ello se registró de la página web del Ministerio de Innovación y Ciencia los proyectos vinculados con las ciencias del deporte (n=155, así como los vinculados con la psicología (n=646. Además se registraron los proyectos concedidos por el Consejo Superior de Deportes (CSD (n=203. De cada uno de los proyectos concedidos se han analizado las siguientes variables: año de concesión, género del investigador principal, nombre del investigador principal, comunidad autónoma, universidad u organismo, cuantía de la concesión, tipología de proyectos, modalidad de proyectos de Psicología del Deporte y tipo de muestra de los proyectos de Psicología del Deporte. Los resultados indican que es mucho mayor la concesión de proyectos de Psicología del Deporte en las convocatorias del Plan Nacional gestionadas dentro del área de gestión de deporte y del Consejo Superior de Deportes, que los que son gestionados dentro del área de gestión de Psicología, y además en todos ellos es mucho mayor el porcentaje de hombres que de mujeres como investigador principal. Las comunidades autónomas de Cataluña, Comunidad Valenciana, Andalucía y Extremadura se reparten más del 70% de los proyectos concedidos en Psicología del Deporte. Entre la Universidad Autónoma de Barcelona, la Universidad de Extremadura y la Universidad de Valencia, se distribuyen más de un tercio del total de proyectos de Psicología del Deporte. La modalidad de Psicología del Deporte con mayor número de proyectos es la de Salud y Calidad de Vida, seguida de Motivación y Emoción y de Psicobiología del Deporte.

Una experiencia de creación de un entorno personal de aprendizaje. Proyecto DIPRO 2.0

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Margarita R. Rodríguez Gallego

2013-01-01

Full Text Available El proyecto DIPRO 2.0 es una de las pocas experiencias que se han desarrollado respecto a la creación de un entorno personal de aprendizaje. En este artículo describimos los objetivos, la secuencia seguida para la implementación del proyecto y unas valoraciones finales sobre el estado del mismo. Los resultados expuestos sobre el proyecto en desarrollo apuntan a elementos valorativos para poder desarrollar acciones de formación y capacitación del profesorado universitario en TIC y el entorno telemático producido supera la visión tradicional de los PLE, en un enfrentamiento con los LMS, y permite incorporar de forma unificada los dos componentes en acciones formativas institucionales.

Percepciones del impacto de la capacitación, compensación y selección del personal en la eficiencia de los proyectos

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Cynthia Alejandra Rueda Contreras

2015-12-01

Full Text Available Este artículo tiene como objetivo investigar los efectos de tres prácticas de gestión de recursos humanos (capacitación, selección de personal y compensación en el éxito de proyectos, medido bajo las percepciones de los gerentes de proyectos sobre los parámetros de costo, tiempo y calidad (eficiencia de proyectos con los que terminan sus proyectos. Este estudio se llevó a cabo en 108 empresas basadas en proyectos de los municipios de Tampico y Victoria registradas en el Directorio Estadístico Nacional de Unidades Económicas, con un muestreo de conveniencia no probabilístico. La recolección de datos se llevó a cabo mediante la distribución del cuestionario por correo electrónico y de manera personal a gerentes de proyectos; para la contrastación de las hipótesis se utilizó un modelo de regresión lineal múltiple mediante el software SPSS versión 21.0. Este estudio es importante para los investigadores y profesionales, ya que busca contribuir a la teoría sobre los factores críticos de éxito (FCE de proyectos y confirmar la gestión de recursos humanos (GRH como uno de ellos, lo cual ayuda a los gerentes de proyectos a mejorar la ejecución de sus trabajos, obteniendo así mayores posibilidades de éxito en ellos. Los resultados de este análisis muestran una influencia positiva de la capacitación y compensación en la eficiencia de proyectos, la cual tiene implicaciones importantes para los directivos de este tipo de empresas interesados en mejorar la eficiencia de los proyectos que realizan, pues no todos los elementos analizados tienen la misma repercusión sobre sus resultados.

Análisis de materiales didácticos para enseñar Ciencias Sociales en Educación Primaria: “Un camino de ida y vuelta”

OpenAIRE

Mon Alday, Estefanía

2013-01-01

Con este Trabajo de Fin de Grado se pretende un acercamiento al tema del análisis de materiales didácticos para enseñar Ciencias Sociales en Educación Primaria y más concretamente se pretende analizar los materiales utilizados con el alumnado de 5º de primaria durante el desarrollo del Proyecto “Un Camino de Ida y Vuelta” en el Colegio Público de Educación Infantil y Primaria “Marqués de Santillana” en la localidad de Palencia. En la primera parte de este trabajo se realiza una revisión t...

El valor de la experimentación en la enseñanza de las ciencias naturales. el taller de ciencias para niños de la sede del atlántico de la universidad de costa rica: una experiencia para compartir

OpenAIRE

María Elena Arce Urbina

2002-01-01

Desde el año 1997, se viene desarrollando en la Sede del Atlántico de la Universidad de Costa Rica, el proyecto didáctico-recreativo denominado Taller de Ciencias para Niños de Segundo Ciclo, el cual tiene como objetivo principal, permitir el acercamiento de los niños y de las niñas a un sistema diferente de enseñanza de las ciencias naturales, a través de un método más atrayente y efectivo, basado en la experimentación. Se parte del principio de que es en ciencias ...

Comunidades indígenas de la provincia de Chimborazo, Ecuador:: permanencia de la sombra del régimen de hacienda

OpenAIRE

Tuaza Castro, Luis Alberto

2014-01-01

Este ensayo analiza la actual situación política indígena, a partir del acercamiento al proceso histórico de las comunidades indígenas de la zona Totorillas del cantón Guamote, Ecuador. Se argumenta que, después de la disolución de la hacienda, emergieron nuevas formas de liderazgo indígena; sin embargo, señala la compleja pervivencia de las antiguas formas de liderazgo que imposibilita la unidad de las comunidades y la consecución de un proyecto político único de largo alcance. This paper...

Monitoreo ante inundaciones en comunidades de la cuenca baja del Rio Ostúa y Lago Guija, Guatemala

OpenAIRE

Carla Gordillo

2017-01-01

El proyecto de investigación Pridca BC 96: Sistema de Monitoreo ante inundaciones en comunidades de la cuenca baja del Rio Ostúa y Lago de Guija, se desarrolló de julio 2014 a diciembre 2015. Las actividades ejecutadas consistieron en la caracterización de la cuenca, elaboración de mapa de susceptibilidad municipal, campaña de sensibilización y taller de selección de comunidades. Se generó un mapa de amenaza y riesgo ante inundación en toda la cuenca y se logró el acercamiento con las comunid...

La investigación arquitectónica, el proyecto de arquitectura y el acondicionamiento ambiental en el proyecto de adecuación de la planta principal del Palacio de Carlos V de Granada

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Muñoz, S

2007-09-01

Full Text Available The Charles V Palace is located in the Complex of Monuments of the Alhambra in Granada; despite the fact that it appears to be a fi nished building according to the design by Pedro Machuca, actually it was never completed. It is a clear example of what modern history writers would term a “longduration” building. Its main fl oor currently houses the Fine Arts Museum of Granada. The proposal to install this museum here was put forward in the 1940s, after the palace was completed in 1928 by Torres Balbás. The project was implemented by F. Prieto Moreno and the museum was opened in 1958. In 2000, the project to adapt the main fl oor of the Charles V Palace was drawn up. This project has already been implemented, although the museum project is expected to be completed in 2007. Based on architectural research, the abovementioned project includes environmental conditioning of the palace rooms, especially light, hygrothermal and air quality conditioning, as well as the installations required for exposition purposes, which mainly guarantee the visual observation of the works of art on display, conservation conditions of these works, visitors’ comfort and energy effi ciency. This article details the respectful way in which this adaptation project is meeting those objectives.El Palacio de Carlos V, situado en el Conjunto Monumental de la Alhambra de Granada, a pesar de su apariencia de edifi cio concluido de acuerdo a un proyecto, el de Pedro Machuca, no llegó a ser ejecutado en su totalidad. Constituye un claro ejemplo de lo que la historiografía moderna denominaría como edifi cio sujeto a “larga duración”. Su planta principal acoge en la actualidad el Museo de Bellas Artes de Granada. Tras el proyecto de terminación del Palacio realizado por Torres Balbás en 1928, la idea de instalar dicho museo se produce en la década de 1940, con un proyecto realizado por F. Prieto Moreno e inaugurado en 1958. En el año 2000 se redacta

Proyecto de Desarrollo Comunitario de Base Cultural en la Comarca de Sahagún

OpenAIRE

Alonso Fernández, María Dulce

2017-01-01

Éste es un proyecto de desarrollo comunitario en la comarca de Sahagún de Campos, perteneciente a la provincia de León. Se trata de un proyecto en el que el factor cultural se toma como un eje del desarrollo local de esta comarca en declive demográfico y económico. El papel de los educadores sociales en este tipo de intervención puede resultar de interés en la estrategia de las Administraciones autonómicas y locales de lucha contra la despoblación. Grado en Educación Social

Metodologías de desarrollo de proyectos informáticos en entornos web

OpenAIRE

Graña Salgado, Rafael

2011-01-01

El presente TFC tiene dos objetivos principales: 1. Determinar el grado de adaptación de las metodologías ágiles al desarrollo de proyectos web puesta en contexto con la adaptación de las metodologías clásicas a este mismo entorno. 2. Realizar una clasificación de las metodologías de desarrollo de software según el grado de adaptación a los proyectos web. Aquest TFC té dos objectius principals: 1. Pretén determinar el grau d'adaptació de les metodologies àgils al desenvolupament de project...

Transcriptomic analysis across nasal, temporal, and macular regions of human neural retina and RPE/choroid by RNA-Seq

Science.gov (United States)

Whitmore, S. Scott; Wagner, Alex H.; DeLuca, Adam P.; Drack, Arlene V.; Stone, Edwin M.; Tucker, Budd A.; Zeng, Shemin; Braun, Terry A.; Mullins, Robert F.; Scheetz, Todd E.

2014-01-01

Proper spatial differentiation of retinal cell types is necessary for normal human vision. Many retinal diseases, such as Best disease and male germ cell associated kinase (MAK)-associated retinitis pigmentosa, preferentially affect distinct topographic regions of the retina. While much is known about the distribution of cell-types in the retina, the distribution of molecular components across the posterior pole of the eye has not been well-studied. To investigate regional difference in molecular composition of ocular tissues, we assessed differential gene expression across the temporal, macular, and nasal retina and retinal pigment epithelium (RPE)/choroid of human eyes using RNA-Seq. RNA from temporal, macular, and nasal retina and RPE/choroid from four human donor eyes was extracted, poly-A selected, fragmented, and sequenced as 100 bp read pairs. Digital read files were mapped to the human genome and analyzed for differential expression using the Tuxedo software suite. Retina and RPE/choroid samples were clearly distinguishable at the transcriptome level. Numerous transcription factors were differentially expressed between regions of the retina and RPE/choroid. Photoreceptor-specific genes were enriched in the peripheral samples, while ganglion cell and amacrine cell genes were enriched in the macula. Within the RPE/choroid, RPE-specific genes were upregulated at the periphery while endothelium associated genes were upregulated in the macula. Consistent with previous studies, BEST1 expression was lower in macular than extramacular regions. The MAK gene was expressed at lower levels in macula than in extramacular regions, but did not exhibit a significant difference between nasal and temporal retina. The regional molecular distinction is greatest between macula and periphery and decreases between different peripheral regions within a tissue. Datasets such as these can be used to prioritize candidate genes for possible involvement in retinal diseases with

Transcriptomic analysis across nasal, temporal, and macular regions of human neural retina and RPE/choroid by RNA-Seq.

Science.gov (United States)

Whitmore, S Scott; Wagner, Alex H; DeLuca, Adam P; Drack, Arlene V; Stone, Edwin M; Tucker, Budd A; Zeng, Shemin; Braun, Terry A; Mullins, Robert F; Scheetz, Todd E

2014-12-01

Proper spatial differentiation of retinal cell types is necessary for normal human vision. Many retinal diseases, such as Best disease and male germ cell associated kinase (MAK)-associated retinitis pigmentosa, preferentially affect distinct topographic regions of the retina. While much is known about the distribution of cell types in the retina, the distribution of molecular components across the posterior pole of the eye has not been well-studied. To investigate regional difference in molecular composition of ocular tissues, we assessed differential gene expression across the temporal, macular, and nasal retina and retinal pigment epithelium (RPE)/choroid of human eyes using RNA-Seq. RNA from temporal, macular, and nasal retina and RPE/choroid from four human donor eyes was extracted, poly-A selected, fragmented, and sequenced as 100 bp read pairs. Digital read files were mapped to the human genome and analyzed for differential expression using the Tuxedo software suite. Retina and RPE/choroid samples were clearly distinguishable at the transcriptome level. Numerous transcription factors were differentially expressed between regions of the retina and RPE/choroid. Photoreceptor-specific genes were enriched in the peripheral samples, while ganglion cell and amacrine cell genes were enriched in the macula. Within the RPE/choroid, RPE-specific genes were upregulated at the periphery while endothelium associated genes were upregulated in the macula. Consistent with previous studies, BEST1 expression was lower in macular than extramacular regions. The MAK gene was expressed at lower levels in macula than in extramacular regions, but did not exhibit a significant difference between nasal and temporal retina. The regional molecular distinction is greatest between macula and periphery and decreases between different peripheral regions within a tissue. Datasets such as these can be used to prioritize candidate genes for possible involvement in retinal diseases with

Photonic crystal light collectors in fish retina improve vision in turbid water.

Science.gov (United States)

Kreysing, Moritz; Pusch, Roland; Haverkate, Dorothee; Landsberger, Meik; Engelmann, Jacob; Ruiter, Janina; Mora-Ferrer, Carlos; Ulbricht, Elke; Grosche, Jens; Franze, Kristian; Streif, Stefan; Schumacher, Sarah; Makarov, Felix; Kacza, Johannes; Guck, Jochen; Wolburg, Hartwig; Bowmaker, James K; von der Emde, Gerhard; Schuster, Stefan; Wagner, Hans-Joachim; Reichenbach, Andreas; Francke, Mike

2012-06-29

Despite their diversity, vertebrate retinae are specialized to maximize either photon catch or visual acuity. Here, we describe a functional type that is optimized for neither purpose. In the retina of the elephantnose fish (Gnathonemus petersii), cone photoreceptors are grouped together within reflecting, photonic crystal-lined cups acting as macroreceptors, but rod photoreceptors are positioned behind these reflectors. This unusual arrangement matches rod and cone sensitivity for detecting color-mixed stimuli, whereas the photoreceptor grouping renders the fish insensitive to spatial noise; together, this enables more reliable flight reactions in the fish's dim and turbid habitat as compared with fish lacking this retinal specialization.

Utilization of glutamine by the retina: an autoradiographic and metabolic study

Energy Technology Data Exchange (ETDEWEB)

Voaden, M J; Lake, N; Marshall, J; Morjaria, B [Institute of Ophthalmology, London (UK). Dept. of Visual Science

1978-10-01

The cells able to accumulate exogenously applied (/sup 3/H) glutamine in rat, cat, frog, pigeon and guinea pig retinas have been located by autoradiography, and the fate of the labelled glutamine, as regards its incorporation into aspartic, glutamic and ..gamma..-amino-butyric acids, followed for 60 min. The results support the notion of glutamine as a precursor of transmitter amino acids in some neurones. In particular, it would appear to be a source of a relatively stable pool of GABA which may be located, with species variation, in amacrine or ganglion cells. In the pigeon retina glutamate pool incorporates and retains a major percentage of the label, and perikarya in the middle of the inner nuclear layer of the tissue are predominantly labelled.

Proyecto de viviendas de interés social en bahareque encementado para el municipio de Villamaría, Colombia

OpenAIRE

Fuentes Aguilar, Cristian; Marcó Navarro, Júlia

2012-01-01

Este proyecto es el proceso de aprendizaje desde cero en la materia del sistema constructivo tradicional de bahareque en Colombia. El proyecto se estructura en primera parte por la introducción, donde plasmamos nuestra visión y relación con el nuevo territorio al que fuimos. También se definen los conceptos principales de la materia del proyecto, como normativas, información referente a las viviendas de interés social, el bambú, nuestra visión del entorno y pr...

Desarrollo de un modelo de predimensionado de costes de construcción en el proyecto arquitectónico

OpenAIRE

Pina Ruiz, Pedro

2014-01-01

El objetivo de la presente investigación es el desarrollo de un modelo de cálculo rápido, eficiente y preciso, para la estimación de los costes finales de construcción, en las fases preliminares del proyecto arquitectónico. Se trata de una herramienta a utilizar durante el proceso de elaboración de estudios previos, anteproyecto y proyecto básico, no siendo por tanto preciso para calcular el “predimensionado de costes” disponer de la total definición grafica y literal del proyecto. Se parte d...

Evaluación de proyectos de servicio social en una universidad mexicana

Directory of Open Access Journals (Sweden)

Ana María Navarrete-Ramírez

2010-06-01

Full Text Available El objetivo del estudio era determinar la calidad de los proyectos de servicio social en que participan estudiantes de la Universidad Autónoma de Yucatán, considerando la opinión de los prestadores, en relación con seis criterios previamente identificados como pertinentes, de acuerdo con la filosofía institucional. Las licenciaturas se organizaron en tres áreas de conocimiento y la evaluación se realizó por medio de un instrumento diseñado y validado por expertos. Se encontró que los prestadores evalúan los proyectos por encima de la media y que hay diferencias significativas en dos criterios de calidad.

Evaluación de proyectos de servicio social en una universidad mexicana

Directory of Open Access Journals (Sweden)

Ana María Navarrete-Ramírez

2010-01-01

Full Text Available El objetivo del estudio era determinar la calidad de los proyectos de servicio social en que participan estudiantes de la Universidad Autónoma de Yucatán, considerando la opinión de los prestadores, en relación con seis criterios previamente identificados como pertinentes, de acuerdo con la filosofía institucional. Las licenciaturas se organizaron en tres áreas de conocimiento y la evaluación se realizó por medio de un instrumento diseñado y validado por expertos. Se encontró que los prestadores evalúan los proyectos por encima de la media y que hay diferencias significativas en dos criterios de calidad.

Local edge detectors: a substrate for fine spatial vision at low temporal frequencies in rabbit retina.

Science.gov (United States)

van Wyk, Michiel; Taylor, W Rowland; Vaney, David I

2006-12-20

Visual acuity is limited by the size and density of the smallest retinal ganglion cells, which correspond to the midget ganglion cells in primate retina and the beta-ganglion cells in cat retina, both of which have concentric receptive fields that respond at either light-On or light-Off. In contrast, the smallest ganglion cells in the rabbit retina are the local edge detectors (LEDs), which respond to spot illumination at both light-On and light-Off. However, the LEDs do not predominate in the rabbit retina and the question arises, what role do they play in fine spatial vision? We studied the morphology and physiology of LEDs in the isolated rabbit retina and examined how their response properties are shaped by the excitatory and inhibitory inputs. Although the LEDs comprise only approximately 15% of the ganglion cells, neighboring LEDs are separated by 30-40 microm on the visual streak, which is sufficient to account for the grating acuity of the rabbit. The spatial and temporal receptive-field properties of LEDs are generated by distinct inhibitory mechanisms. The strong inhibitory surround acts presynaptically to suppress both the excitation and the inhibition elicited by center stimulation. The temporal properties, characterized by sluggish onset, sustained firing, and low bandwidth, are mediated by the temporal properties of the bipolar cells and by postsynaptic interactions between the excitatory and inhibitory inputs. We propose that the LEDs signal fine spatial detail during visual fixation, when high temporal frequencies are minimal.

Modelos para Asistir la Gestión de Proyectos de Explotación de Información

Directory of Open Access Journals (Sweden)

Pablo Pytel

2013-02-01

Full Text Available Los proyectos de Explotación de Información son un tipo especial de proyecto de Ingeniería en Software. En lugar de requerir desarrollar un software específico, herramientas disponibles son utilizadas que ya incluyen las técnicas y algoritmos necesarios. Pero de todas formas posee problemas similares al existir cuestiones de gestión que todavía deben ser mejorados. Entre estas cuestiones se destaca la necesidad de un análisis de viabilidad que permita identificar los riesgos en forma temprana y un método de estimación de esfuerzo que asista la planificación de actividades y recursos que son necesarios para desarrollar el proyecto. En este contexto, este trabajo tiene como objetivo proponer y estudiar dos modelos para ser utilizados en Pequeñas y Medianas Empresas al comienzo de un proyecto de Explotación de Información y de esta forma buscar reducir los problemas que se pueden presentar.

Flash photolysis of rhodopsin in the cat retina

International Nuclear Information System (INIS)

Ripps, H.; Mehaffey, L.; Siegel, I.M.; Ernst, W.; Kemp, C.M.

1981-01-01

The bleaching of rhodopsin by short-duration flashes of a xenon discharge lamp was studied in vivo in the cat retina with the aid of a rapid, spectral-scan fundus reflectometer. Difference spectra recorded over a broad range of intensities showed that the bleaching efficacy of high-intensity flashes was less than that of longer duration, steady lights delivering the same amount of energy. Both the empirical results and those derived from a theoretical analysis of flash photolysis indicate that, under the conditions of these experiments, the upper limit of the flash bleaching of rhodopsin in cat is approximately 90%. Although the fact that a full bleach could not be attained is attributable to photoreversal, i.e., the photic regeneration of rhodopsin from its light-sensitive intermediates, the 90% limit is considerably higher than the 50% (or lower) value obtained under other experimental circumstances. Thus, it appears that the duration (approximately 1 ms) and spectral composition of the flash, coupled with the kinetic parameters of the thermal and photic reactions in the cat retina, reduce the light-induced regeneration of rhodopsin to approximately 10%

Proyecto "Empiezo a ser bilingüe"

OpenAIRE

Fernández Trujillo, Ruth

2009-01-01

Este proyecto pretende iniciar a los niños del segundo ciclo de Infantil en la lengua inglesa desde una perspectiva bilingüe, es decir, ampliando el uso y aprendizaje de dicho idioma en actividades cotidianas desarrolladas típicamente en la lengua materna (el castellano) a la vez que se introducen nuevos contenidos que adentran a los alumnos en una nueva cultura, la inglesa. En todo este planteamiento, el cual es complementario e independiente de la enseñanza tra...

Sexualidades marginalizadas: un acercamiento a la zona de tolerancia en Cali, 1960-1970

Directory of Open Access Journals (Sweden)

Diana Carolina Gutiérrez Ramírez

2016-01-01

Full Text Available Interesa al presente artículo la zona de tolerancia como receptáculo de sexualidades marginalizadas en el que pululan prácticas, sujetos e imaginarios anormales, inmorales y transgresores a la norma sexual en la ciudad de Cali, entre 1960 y 1970. A partir de lo anterior se posibilitará un acercamiento al Estado como ejecutor de poder y a la zona como un lugar donde habita, vive y existe la diferencia. Teniendo presentes las dinámicas típicas de este espacio, se prestará atención a la forma como este lugar se convirtió en el sitio idóneo de venta y circulación del mercado pornográfico de la época. Esto con el fin de comprender el surgimiento y popularización de la narrativa pornográfica del escritor caleño Hernán Hoyos. En ese momento se realizará una lectura sobre los imaginarios y lugares comunes que se configuran en la obra de este autor. Por último, se intentará comprender al libro pornográfico, y las realidades que allí se tejen, como elemento configurador de la cultura popular.

STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF BENIGN FLECK RETINA USING MULTIMODAL IMAGING.

Science.gov (United States)

Neriyanuri, Srividya; Rao, Chetan; Raman, Rajiv

2017-01-01

To report structural and functional features in a case series of benign fleck retina using multimodal imaging. Four cases with benign fleck retina underwent complete ophthalmic examination that included detailed history, visual acuity, and refractive error testing, FM-100 hue test, dilated fundus evaluation, full field electroretinogram, fundus photography with autofluorescence, fundus fluorescein angiography, and swept-source optical coherence tomography. Age group of the cases ranged from 19 years to 35 years (3 males and 1 female). Parental consanguinity was reported in two cases. All of them were visually asymptomatic with best-corrected visual acuity of 20/20 (moderate astigmatism) in both the eyes. Low color discrimination was seen in two cases. Fundus photography showed pisciform flecks which were compactly placed on posterior pole and were discrete, diverging towards periphery. Lesions were seen as smaller dots within 1500 microns from fovea and were hyperfluorescent on autofluorescence. Palisading retinal pigment epithelium defects were seen in posterior pole on fundus fluorescein angiography imaging; irregular hyper fluorescence was also noted. One case had reduced cone responses on full field electroretinogram; the other three cases had normal electroretinogram. On optical coherence tomography, level of lesions varied from retinal pigment epithelium, inner segment to outer segment extending till external limiting membrane. Functional and structural deficits in benign fleck retina were picked up using multimodal imaging.

Proyectos pilotos WHIX de energía renovable y seguridad ambiental en El Salvador.

OpenAIRE

Ochoa Córdova, Carlos Roberto

2008-01-01

El Programa WHIX aporta proyectos de Energía y Medio Ambiente para abrir un diálogo entre los militares de la Región, organizaciones gubernamentales y no-gubernamentales y sus equivalentes en los EE.UU. Este programa cataliza proyectos de energía renovable y el medioambiente para demostrar y validar estas tecnologías en los países de la región. Al mismo tiempo provee un foro de intercambio internacional de las “Mejores Prácticas” y la oportunidad de trabajar en conjunto en promisorias investi...

Heidelberg Retina Tomograph for the Detection of Glaucoma

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Barbara Cvenkel

2012-06-01

Full Text Available Heidelberg Retina Tomograph (HRT is a confocal scanning laser ophthalmoscope which acquires and analyzes 3-dimensional images of the optic nerve head. The latest instrument HRT3 includes software with larger ethinic-specific normative database. This review summarizes relevant published literature on HRT in diagnosing glaucoma, detecting glaucoma progression, the diagnostic accuracy of HRT among other imaging devices and its role in clinical practice.

Localization and characterization of immunocompetent cells in the human retina

NARCIS (Netherlands)

Yang, P.; Das, P. K.; Kijlstra, A.

2000-01-01

Recent studies have shown that experimental uveitis can be induced by the appropriate administration of various retinal antigens. Little is known about the in-situ interactions between immune cells in the retina as a prerequisite for understanding the mechanisms involving the presentation of

Retina Image Analysis and Ocular Telehealth: The Oak Ridge National Laboratory-Hamilton Eye Institute Case Study

Energy Technology Data Exchange (ETDEWEB)

Karnowski, Thomas Paul [ORNL; Giancardo, Luca [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2013-01-01

Automated retina image analysis has reached a high level of maturity in recent years, and thus the question of how validation is performed in these systems is beginning to grow in importance. One application of retina image analysis is in telemedicine, where an automated system could enable the automated detection of diabetic retinopathy and other eye diseases as a low-cost method for broad-based screening. In this work we discuss our experiences in developing a telemedical network for retina image analysis, including our progression from a manual diagnosis network to a more fully automated one. We pay special attention to how validations of our algorithm steps are performed, both using data from the telemedicine network and other public databases.

Proyecto de desarrollo de una base de datos

OpenAIRE

Boshoff de Jong, Etienne

2013-01-01

Desarrollo de las fases de planificación, análisis, diseño e implementación de un proyecto de desarrollo de una base de datos para un cliente ficticio. Desenvolupament de les fases de planificació, anàlisi, disseny i implementació d'un projecte de desenvolupament d'una base de dades per a un client fictici. Bachelor thesis for the Computer Science program on Databases.

Infrared reflectance as a diagnostic adjunct for subclinical commotio retinae

Directory of Open Access Journals (Sweden)

Nicholas H Andrew

2014-01-01

Full Text Available Commotio retinae (CR is an outer retinal disorder following blunt trauma to the eye. Histologically it is characterized by disruption of the photoreceptor outer segments (OS, typically without injury to other retinal layers. Using spectral-domain optical coherence tomography (OCT the condition is visible as hyper-reflectivity of the OS. Most cases of CR are associated with transient grey-white discoloration of the retina and are easily diagnosed clinically, but there have been reports of OCT-confirmed CR without retinal discoloration. It is likely that this subclinical variant of CR is under-recognized as the OCT features of CR are subtle. Here, we report a case of OCT-confirmed subclinical CR that demonstrated prominent infrared hypo-reflectance, using the infrared protocol of the SPECTRALIS® OCT, Heidelberg Engineering. This case suggests that infrared reflectance may have a role in diagnosing cases of subclinical CR.

Propuesta metodológica para el diseño del proyecto de curso virtual: Aplicación piloto

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Renata Marciniak

2017-09-01

Full Text Available Para que un curso virtual se realice de forma adecuada, debe proyectarse correctamente. El objetivo de este artículo es proporcionar una metodología para diseñar un proyecto de curso virtual, evaluarlo y seguir su realización. La metodología propone el seguimiento de las seis fases siguientes: análisis del problema educativo; justificación y objetivos del proyecto; propuesta de perspectivas del proyecto; planificación pedagógica, operativa y económica; proyección de resultados esperados, evaluación continua y seguimiento del proyecto. De acuerdo con la metodología, se proyectó e implementó el curso virtual “Uso de rúbricas para evaluar las actividades de aprendizaje en línea”, que se impartió en una universidad a distancia en Polonia. Aunque los participantes valoraron el curso positivamente, sus opiniones sugieren la necesidad de mejorar los elementos pedagógicos. Este proyecto permitió obtener respuestas a las preguntas fundamentales que plantean las decisiones centrales implícitas en el proyecto de un curso: ¿qué se piensa hacer?, ¿por qué?, ¿para qué?, ¿cómo?, ¿cuándo?, ¿quiénes lo van a hacer?, ¿cuáles son los recursos con los que se va a desarrollar y financiar? Se concluye que la metodología propuesta puede constituir un marco de referencia para las universidades que pretendan crear un curso virtual de calidad, ya sea en Polonia o en otros países.

PGC-1α determines light damage susceptibility of the murine retina.

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Anna Egger

Full Text Available The peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1 proteins are key regulators of cellular bioenergetics and are accordingly expressed in tissues with a high energetic demand. For example, PGC-1α and PGC-1β control organ function of brown adipose tissue, heart, brain, liver and skeletal muscle. Surprisingly, despite their prominent role in the control of mitochondrial biogenesis and oxidative metabolism, expression and function of the PGC-1 coactivators in the retina, an organ with one of the highest energy demands per tissue weight, are completely unknown. Moreover, the molecular mechanisms that coordinate energy production with repair processes in the damaged retina remain enigmatic. In the present study, we thus investigated the expression and function of the PGC-1 coactivators in the healthy and the damaged retina. We show that PGC-1α and PGC-1β are found at high levels in different structures of the mouse retina, most prominently in the photoreceptors. Furthermore, PGC-1α knockout mice suffer from a striking deterioration in retinal morphology and function upon detrimental light exposure. Gene expression studies revealed dysregulation of all major pathways involved in retinal damage and apoptosis, repair and renewal in the PGC-1α knockouts. The light-induced increase in apoptosis in vivo in the absence of PGC-1α was substantiated in vitro, where overexpression of PGC-1α evoked strong anti-apoptotic effects. Finally, we found that retinal levels of PGC-1 expression are reduced in different mouse models for retinitis pigmentosa. We demonstrate that PGC-1α is a central coordinator of energy production and, importantly, all of the major processes involved in retinal damage and subsequent repair. Together with the observed dysregulation of PGC-1α and PGC-1β in retinitis pigmentosa mouse models, these findings thus imply that PGC-1α might be an attractive target for therapeutic approaches aimed at retinal

Functional characterization of rs2229094 (T>C polymorphism in the tumor necrosis factor locus and lymphotoxin alpha expression in human retina: the Retina 4 project

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Pastor-Idoate S

2017-05-01

Full Text Available Salvador Pastor-Idoate,1,2 Irene Rodríguez-Hernández,2,3 Jimena Rojas,1 Lucia Gonzalez-Buendia,1 Santiago Delgado-Tirado,1,4 Jose Carlos López,1 Rogelio González-Sarmiento,2,3 Jose C Pastor1,4 1IOBA Eye Institute, University of Valladolid, Valladolid, 2Molecular Medicine Unit, Department of Medicine, 3Molecular and Cellular Cancer Biology Institute, High Council of Scientific Research, Biomedical Research Institute of Salamanca, University of Salamanca, Salamanca, 4Department of Ophthalmology, Hospital Clínico Universitario, Valladolid, Spain Purpose: The objective of this study is to determine the expression and localization of lymphotoxin alpha (LTA in human retinas and the functionality of one of its polymorphisms rs2229094 (C13R (T>C, previously associated with proliferative vitreoretinopathy (PVR development.Materials and methods: Total RNA from three healthy human retinas were extracted and subjected to reverse transcription-polymerase chain reaction (RT-PCR analysis, using flanking primers of LTA cDNA. In addition, three human eyes with retinal detachment (RD and three healthy control eyes were subjected to immunohistochemistry (IHC with a specific antibody against LTA. The functionality of T and C alleles was assessed by using pCEFL-Flag expression vector and transient transfection assays in COS-1 cell line. In addition, expression analysis by RT-PCR, Western blot and subcellular localization of both alleles and by immunofluorescence assay was performed.Results: RT-PCR analysis revealed no significant levels of messenger RNA (mRNA LTA in healthy human retinas. Sequential IHC staining showed differences between healthy human and RD retinas. No differences in mRNA and protein expression levels and in subcellular localization between both alleles were found. Both alleles were located in the cytoplasm of COS-1 cells.Conclusion: Although results suggest lack of functionality, the differences found in IHC study and its strong association

Heparin-Binding EGF-like Growth Factor (HB-EGF) stimulates the proliferation of Müller glia-derived progenitor cells in avian and murine retinas

Science.gov (United States)

Todd, Levi; Volkov, Leo I.; Zelinka, Chris; Squires, Natalie; Fischer, Andy J.

2015-01-01

Müller glia can be stimulated to de-differentiate, proliferate and form Müller glia-derived progenitor cells (MGPCs) that regenerate retinal neurons. In the zebrafish retina, Heparin-Binding EGF-like Growth Factor (HB-EGF) may be one of the key factors that stimulate the formation of proliferating MGPCs. Currently nothing is known about the influence of HB-EGF on the proliferative potential of Müller glia in retinas of birds and rodents. In the chick retina, we found that levels of both hb-egf and egf-receptor are rapidly and transiently up-regulated following NMDA-induced damage. Although intraocular injections of HB-EGF failed to stimulate cell-signaling or proliferation of Müller glia in normal retinas, HB-EGF stimulated proliferation of MGPCs in damaged retinas. By comparison, inhibition of the EGF-receptor (EGFR) decreased the proliferation of MGPCs in damaged retinas. HB-EGF failed to act synergistically with FGF2 to stimulate the formation of MGPCs in the undamaged retina and inhibition of EGF-receptor did not suppress FGF2-mediated formation of MGPCs. In the mouse retina, HB-EGF stimulated the proliferation of Müller glia following NMDA-induced damage. Furthermore, HB-EGF stimulated not only MAPK-signaling in Müller glia/MGPCs, but also activated mTor- and Jak/Stat-signaling. We propose that levels of expression of EGFR are rate-limiting to the responses of Müller glia to HB-EGF and the expression of EGFR can be induced by retinal damage, but not by FGF2-treatment. We conclude that HB-EGF is mitogenic to Müller glia in both chick and mouse retinas, and HB-EGF is an important player in the formation of MGPCs in damaged retinas. PMID:26500021

3D finite element modeling of epiretinal stimulation: Impact of prosthetic electrode size and distance from the retina.

Science.gov (United States)

Sui, Xiaohong; Huang, Yu; Feng, Fuchen; Huang, Chenhui; Chan, Leanne Lai Hang; Wang, Guoxing

2015-05-01

A novel 3-dimensional (3D) finite element model was established to systematically investigate the impact of the diameter (Φ) of disc electrodes and the electrode-to-retina distance on the effectiveness of stimulation. The 3D finite element model was established based on a disc platinum stimulating electrode and a 6-layered retinal structure. The ground electrode was placed in the extraocular space in direct attachment with sclera and treated as a distant return electrode. An established criterion of electric-field strength of 1000 Vm-1 was adopted as the activation threshold for RGCs. The threshold current (TC) increased linearly with increasing Φ and electrode-to-retina distance and remained almost unchanged with further increases in diameter. However, the threshold charge density (TCD) increased dramatically with decreasing electrode diameter. TCD exceeded the electrode safety limit for an electrode diameter of 50 µm at an electrode-to-retina distance of 50 to 200 μm. The electric field distributions illustrated that smaller electrode diameters and shorter electrode-to-retina distances were preferred due to more localized excitation of RGC area under stimulation of different threshold currents in terms of varied electrode size and electrode-to-retina distances. Under the condition of same-amplitude current stimulation, a large electrode exhibited an improved potential spatial selectivity at large electrode-to-retina distances. Modeling results were consistent with those reported in animal electrophysiological experiments and clinical trials, validating the 3D finite element model of epiretinal stimulation. The computational model proved to be useful in optimizing the design of an epiretinal stimulating electrode for prosthesis.

Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm

OpenAIRE

Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

2014-01-01

We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same ...

[VEGF expression in dog retina after chorioretinal venous anastomosis].

Science.gov (United States)

Lu, Ning; Li, Zhihui; Sun, Xianli; Wang, Guanglu; Zhang, Feng; Peng, Xiaoyan

2002-09-01

To identify changes in vascular endothelial growth factor (VEGF) expression in the dog retina after laser-induced chorioretinal venous anastomosis (CRVA), in order to find out the relationship between CRVA treatment and the related neovascular complications. Immediately after branch retinal vein occlusion (BRVO) model was made in 5 eyes of 5 normal dogs, CRVA treatment was done over a small tributary vein in the drainage distribution of the occluded vein. In each eye, there were 2 - 3 treatment sites. Four to six weeks later, a repeated treatment was given if the first treatment failed to show the anastomosis. The treatment sites with successful CRVA were divided into two groups: the small laser spot group, which received one treatment and the big laser spot group, which received more than one treatment. The expression of VEGF was investigated immunohistochemically in the treatment sites with successful anastomoses and in the 5 normal fellow eyes (control). There were totally 10 successful anastomoses in the 5 experimental eyes, among which, five received one treatment and the other 5 received more than one treatment. On fundus examination, the small laser spots were round and small, and the big laser spots were large with local proliferation. VEGF immunoreactivity was absent/weak in the normal dog retina, and remained unchanged in the small laser spot group, but somewhat increased in the big laser spot group. No neovascular complications occurred. All immunostaining experiments were accompanied by proper controls and none of the negative controls showed any immunoreactivity. Proper laser treatment can induce CRVA quite safely in nonischemic dog retina, which does not cause changes in the expression of VEGF, but severe laser damage in the treatment site can cause increased VEGF expression which may be related to neovascular complications.

Simulated human eye retina adaptive optics imaging system based on a liquid crystal on silicon device

International Nuclear Information System (INIS)

Jiang Baoguang; Cao Zhaoliang; Mu Quanquan; Hu Lifa; Li Chao; Xuan Li

2008-01-01

In order to obtain a clear image of the retina of model eye, an adaptive optics system used to correct the wave-front error is introduced in this paper. The spatial light modulator that we use here is a liquid crystal on a silicon device instead of a conversional deformable mirror. A paper with carbon granule is used to simulate the retina of human eye. The pupil size of the model eye is adjustable (3-7 mm). A Shack–Hartman wave-front sensor is used to detect the wave-front aberration. With this construction, a value of peak-to-valley is achieved to be 0.086 λ, where λ is wavelength. The modulation transfer functions before and after corrections are compared. And the resolution of this system after correction (691p/m) is very close to the dirraction limit resolution. The carbon granule on the white paper which has a size of 4.7 μm is seen clearly. The size of the retina cell is between 4 and 10 mu;m. So this system has an ability to image the human eye's retina. (classical areas of phenomenology)

Segmentasi Pembuluh Darah Retina Pada Citra Fundus Menggunakan Gradient Based Adaptive Thresholding Dan Region Growing

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Deni Sutaji

2016-07-01

Full Text Available AbstrakSegmentasi pembuluh darah pada citra fundus retina menjadi hal yang substansial dalam dunia kedokteran, karena dapat digunakan untuk mendeteksi penyakit, seperti: diabetic retinopathy, hypertension, dan cardiovascular. Dokter membutuhkan waktu sekitar dua jam untuk mendeteksi pembuluh darah retina, sehingga diperlukan metode yang dapat membantu screening agar lebih cepat.Penelitian sebelumnya mampu melakukan segmentasi pembuluh darah yang sensitif terhadap variasi ukuran lebar pembuluh darah namun masih terjadi over-segmentasi pada area patologi. Oleh karena itu, penelitian ini bertujuan untuk mengembangkan metode segmentasi pembuluh darah pada citra fundus retina yang dapat mengurangi over-segmentasi pada area patologi menggunakan Gradient Based Adaptive Thresholding dan Region Growing.Metode yang diusulkan terdiri dari 3 tahap, yaitu segmentasi pembuluh darah utama, deteksi area patologi dan segmentasi pembuluh darah tipis. Tahap segmentasi pembuluh darah utama menggunakan high-pass filtering dan tophat reconstruction pada kanal hijau citra yang sudah diperbaiki kontrasnya sehingga lebih jelas perbedaan antara pembuluh darah dan background. Tahap deteksi area patologi menggunakan metode Gradient Based Adaptive Thresholding. Tahap segmentasi pembuluh darah tipis menggunakan Region Growing berdasarkan informasi label pembuluh darah utama dan label area patologi. Hasil segmentasi pembuluh darah utama dan pembuluh darah tipis kemudian digabungkan sehingga menjadi keluaran sistem berupa citra biner pembuluh darah. Berdasarkan hasil uji coba, metode ini mampu melakukan segmentasi pembuluh darah retina dengan baik pada citra fundus DRIVE, yaitu dengan akurasi rata-rata 95.25% dan nilai Area Under Curve (AUC pada kurva Relative Operating Characteristic (ROC sebesar 74.28%.                           Kata Kunci: citra fundus retina, gradient based adaptive thresholding, patologi, pembuluh darah retina, region growing

Adaptive Optical System for Retina Imaging Approaches Clinic Applications

Science.gov (United States)

Ling, N.; Zhang, Y.; Rao, X.; Wang, C.; Hu, Y.; Jiang, W.; Jiang, C.

We presented "A small adaptive optical system on table for human retinal imaging" at the 3rd Workshop on Adaptive Optics for Industry and Medicine. In this system, a 19 element small deformable mirror was used as wavefront correction element. High resolution images of photo receptors and capillaries of human retina were obtained. In recent two years, at the base of this system a new adaptive optical system for human retina imaging has been developed. The wavefront correction element is a newly developed 37 element deformable mirror. Some modifications have been adopted for easy operation. Experiments for different imaging wavelengths and axial positions were conducted. Mosaic pictures of photoreceptors and capillaries were obtained. 100 normal and abnormal eyes of different ages have been inspected.The first report in the world concerning the most detailed capillary distribution images cover ±3° by ± 3° field around the fovea has been demonstrated. Some preliminary very early diagnosis experiment has been tried in laboratory. This system is being planned to move to the hospital for clinic experiments.

Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina.

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Tracy Ho

Full Text Available Amyloid precursor protein (APP is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry.

GABA sensitivity of spectrally classified horizontal cells in goldfish retina

NARCIS (Netherlands)

Verweij, J.; Kamermans, M.; Negishi, K.; Spekreijse, H.

1998-01-01

We studied the GABA sensitivity of horizontal cells in the isolated goldfish retina. After the glutamatergic input to the horizontal cells was blocked with DNQX, GABA depolarized the monophasic and biphasic horizontal cells. The pharmacology of these GABA-induced depolarizations was tested with the

Documentación de requisitos en proyectos de explotación de información

OpenAIRE

Pollo Cattaneo, María Florencia; Pytel, Pablo; Diez, Eduardo; Rodríguez, Dario; García Martínez, Ramón; Mansilla, Diego; Vegega, Cinthia

2012-01-01

El proceso de Educción de Requisitos para Proyectos de Explotación de Información, contempla la realización de un conjunto de plantillas que se utilizan para documentar los conceptos educidos durante las primeras fases del proyecto. Por otro lado, la Ingeniería del Conocimiento (INCO) se encarga de la construcción de Sistemas Basados en Conocimientos, intentando representar el conocimiento y comportamiento inteligente de los seres humanos en un sistema artificial. Los Ingenieros del Conocimie...

Diseño de una matriz de análisis para temas ambientales en proyectos de ciencias naturales

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Ana Ilse Benavides Lahnstein

2015-12-01

Full Text Available RESUMEN. En ésta investigación estudiamos los contenidos ambientales de dos proyectos de ciencias naturales del libro de texto para el sexto año de educación primaria en México. El trabajo por proyectos, el cual fue formalmente introducido al sistema de educación básica en el último proceso de reforma, es presentado como una estrategia para consolidar el conocimiento de los estudiantes para alcanzar los aprendizajes esperados. Nuestro estudio se guío por dos preguntas principales: ¿Satisfacen los contenidos ambientales de los proyectos seleccionados los aprendizajes esperados del currículo de ciencias naturales para sexto grado? ¿Son estos contenidos ambientales pertinentes con las problemáticas actuales de la educación ambiental para la sustentabilidad? Para contestarlas realizamos una investigación documental en documentos oficiales y diseñamos un instrumento para la codificación y el análisis del contenido de los proyectos. Los resultados se discutieron en tres unidades de análisis de acuerdo a los tres niveles de complejidad planteados en la matriz. Identificamos en los proyectos contenidos ambientales básicos con referencia a los aprendizajes esperados. Consideramos que el éxito potencial del contenido ambiental depende de las competencias de los docentes y de los estudiantes para ponerlos en práctica efectivamente.

Proyecto curricular institucional: Una alternativa para el cambio

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Ruth Vallejo

2002-01-01

Full Text Available Enfrentar el desafío de la construcción del proyecto curricular institucional representa para la educación de este milenio una prioridad, esto sin lugar a dudas, requiere de un cambio en la estructura organizativa y de gestión en cada plantel; el Currículo Básico Nacional, en marcha, representa un avance significativo, para superar esta situación. Para que esta reforma constituya una alternativa válida, es necesario abordar la formación del docente de forma sistemática, continúa desde su praxis por medio de la investigación-acción, utilizando herramientas metodológicas para el diagnóstico y acompañando todo el proceso con una evaluación institucional que al mismo tiempo que se analiza e implementa permita la formación de los actores involucrados; la revisión y los ajustes permanentes conducen a la construcción de aproximaciones sucesivas que con el trabajo concertado garantizan la viabilidad del proyecto. Se recomienda asumirlo con un carácter cíclico y dinámico para decidir si se puede o no mantener a la luz de los cambios que ocurran dentro y fuera del proceso.

Evaluation of the central macula in commotio retinae not associated with other types of traumatic retinopathy.

Science.gov (United States)

Park, Joo Youn; Nam, Woo Ho; Kim, Seung Hoon; Jang, Sun Young; Ohn, Young-Hoon; Park, Tae Kwann

2011-08-01

To report on the anatomical and functional changes to the macula in nine patients suffering from commotio retinae not accompanied by any other types of traumatic retinopathy. Nine injured eyes with commotio retinae were evaluated soon after ocular trauma with ophthalmic examination, including Spectral-domain optical coherence tomography (SD-OCT). In 12 eyes of 6 patients, Humphrey visual field (HVF) and multifocal electroretinogram (mfERG) were performed. Re-examinations were periodically performed for a mean of 26 days. Data from 9 injured eyes were collected and compared to data collected from the 9 non-affected eyes of the same patients. SD-OCT revealed no significant differences in the foveal thickness and total macular volume between traumatized and intact eyes in all 9 patients. Only 3 out of the 9 injured eyes showed abnormal findings in SD-OCT images such as discontinuity of the inner/outer segment (IS/OS) junction or abnormal hyper-reflectivity from the IS/OS and retinal pigment epithelium (RPE) lines in the macula. HVF and mfERG results did not show any functional deterioration in the injured eyes compared with intact eyes. During follow-up, the commotio retinae resolved in all 9 eyes. The changes to the outer retinal region detected in 3 patients by SD-OCT were also resolved. Acute retinal changes in commotio retinae, not associated with other retinal pathologies, were resolved without histological and functional sequelae. In a few cases of commotio retinae, SD-OCT revealed transient abnormalities mainly observed at the IS/OS and RPE complexes.

Quantitative analysis of retina layer elasticity based on automatic 3D segmentation (Conference Presentation)

Science.gov (United States)

He, Youmin; Qu, Yueqiao; Zhang, Yi; Ma, Teng; Zhu, Jiang; Miao, Yusi; Humayun, Mark; Zhou, Qifa; Chen, Zhongping

2017-02-01

Age-related macular degeneration (AMD) is an eye condition that is considered to be one of the leading causes of blindness among people over 50. Recent studies suggest that the mechanical properties in retina layers are affected during the early onset of disease. Therefore, it is necessary to identify such changes in the individual layers of the retina so as to provide useful information for disease diagnosis. In this study, we propose using an acoustic radiation force optical coherence elastography (ARF-OCE) system to dynamically excite the porcine retina and detect the vibrational displacement with phase resolved Doppler optical coherence tomography. Due to the vibrational mechanism of the tissue response, the image quality is compromised during elastogram acquisition. In order to properly analyze the images, all signals, including the trigger and control signals for excitation, as well as detection and scanning signals, are synchronized within the OCE software and are kept consistent between frames, making it possible for easy phase unwrapping and elasticity analysis. In addition, a combination of segmentation algorithms is used to accommodate the compromised image quality. An automatic 3D segmentation method has been developed to isolate and measure the relative elasticity of every individual retinal layer. Two different segmentation schemes based on random walker and dynamic programming are implemented. The algorithm has been validated using a 3D region of the porcine retina, where individual layers have been isolated and analyzed using statistical methods. The errors compared to manual segmentation will be calculated.

Convenio de contratación para el proyecto de la iglesia Saint-Pierre de Firminy-Vert

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Merwan Chaverra Suárez

2010-12-01

Full Text Available Los pormenores del proceso de contratación para el encargo de la iglesia Saint-Pierre de Firminy-Vert, entre 1960 y 1963, corresponde al desglose de las conversaciones e intercambios de correspondencia entre el arquitecto y sus clientes, que dieron lugar a un número de versiones y variantes del proyecto, así como a dificultades administrativas y económicas, que se prolongaron en el tiempo, hasta la firma del contrato. El proyecto de la iglesia Saint-Pierre de Firminy-Vert cuenta con un dossier completo, guardado y archivado en la Fundación Le Corbusier, que garantiza poder efectuar un análisis total del proyecto, enfocándolo en una metodología que posibilite el entendimiento y la reconstrucción de los hechos a partir de las fuentes primarias.

La evaluación de los riesgos ambientales y su aplicación a los proyectos de desarrollo limpio

OpenAIRE

Alfredo Cabezas Ares

2009-01-01

La ONU a través del PNUMA está auspiciando la financiación de proyectos de inversión que supongan una reducción de la Emisión de Gases de Efecto Invernadero o su absorción. Muchos de estos proyectos se ubican en países en vías de desarrollo, lo cual en esencia es beneficioso desde el punto de vista económico especialmente para las ubicaciones seleccionadas. En este trabajo se estudia como evaluar los riesgos ambientales de los proyectos de Desarrollo Limpio, teniendo especial consideración de...

Near UV radiation effect on the lens and retina

International Nuclear Information System (INIS)

Zigman, S.

1987-01-01

The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

Proyectos de extensión de la facultad

OpenAIRE

Revista Institucional de la Facultad de Ciencias Económicas

2011-01-01

La Secretaria de Extensión Universitaria de la Facultad de Ciencias Económicas, presentó a la convocatoria del año 2010 de proyectos de extensión de la Universidad Nacional de La Plata, siete propuestas que fueron analizadas por un banco de evaluadores encargado de establecer el orden de mérito para la acreditación y subsidio de los mismos. Facultad de Ciencias Económicas

Cannabinoid Receptor Type 1 Expression in the Developing Avian Retina: Morphological and Functional Correlation With the Dopaminergic System

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Luzia da Silva Sampaio

2018-03-01

Full Text Available The avian retina has been used as a model to study signaling by different neuro- and gliotransmitters. It is unclear how dopaminergic and cannabinoid systems are related in the retina. Here we studied the expression of type 1 and 2 cannabinoid receptors (CB1 and CB2, as well as monoacylglycerol lipase (MAGL, the enzyme that degrades 2-arachidonoylglycerol (2-AG, during retina development. Our data show that CB1 receptor is highly expressed from embryonic day 5 (E5 until post hatched day 7 (PE7, decreasing its levels throughout development. CB1 is densely found in the ganglion cell layer (GCL and inner plexiform layer (IPL. CB2 receptor was also found from E5 until PE7 with a decrease in its contents from E9 afterwards. CB2 was mainly present in the lamination of the IPL at PE7. MAGL is expressed in all retinal layers, mainly in the IPL and OPL from E9 to PE7 retina. CB1 and CB2 were found both in neurons and glia cells, but MAGL was only expressed in Müller glia. Older retinas (PE7 show CB1 positive cells mainly in the INL and co-expression of CB1 and tyrosine hydroxylase (TH are shown in a few cells when both systems are mature. CB1 co-localized with TH and was heavily associated to D1 receptor labeling in primary cell cultures. Finally, cyclic AMP (cAMP was activated by the selective D1 agonist SKF38393, and inhibited when cultures were treated with WIN55, 212–2 (WIN in a CB1 dependent manner. The results suggest a correlation between the endocannabinoid and dopaminergic systems (DSs during the avian retina development. Activation of CB1 limits cAMP accumulation via D1 receptor activation and may influence embryological parameters during avian retina differentiation.

El proyecto «escuela: espacio de paz» como elementos de mejora de la convivencia escolar

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M.ª Ángeles DÍAZ LINARES

2010-11-01

Full Text Available En la tesis doctoral presentada se aborda el estudio llevado a cabo en centros públicos y concertados, de distintos niveles educativos no universitarios de la Comunidad Autónoma de Andalucía, con el fin de determinar si los Proyectos «escuela: espacio de Paz» (PeeP son instrumentos capaces de prevenir la violencia y mejorar la convivencia, en el marco del Proyecto educativo de los centros escolares.

Incidencia del proyecto “ASEAN community” en el desarrollo humano de Tailandia (2004-2014)

OpenAIRE

Meneses Mendoza, Lizeth Alejandra

2016-01-01

Esta investigación se interesa en evaluar los logros y retos que ha presentado el proyecto ASEAN Community en cada una de sus tres áreas de acción (Comunidad económica, comunidad de política y seguridad, y comunidad socio-cultural) ante su aplicación en Tailandia. De esta manera, se busca analizar la incidencia que ha tenido el proyecto en el Desarrollo Humano de Tailandia durante el periodo 2004-2014. A través del análisis del estatus actual a la luz del concepto de libertades instrumentale...

Los proyectos de cooperación: una alternativa al tiempo libre de alumnos universitarios

OpenAIRE

Beatriz Núñez Angulo; Rafael Calvo de León; Jesús Mª Álvarez Martínez

2014-01-01

Es sabido por todos que la Universidad ha de fomentar los Proyectos de Cooperación, como función social. Presentamos la trayectoria de un proyecto de Cooperación al Desarrollo de la Universidad de Burgos que, a lo largo de 10 años se ha ido consolidando y ha permitido la participación directa de 88 personas entre profesores y alumnos, siendo una alternativa al tiempo libre del alumnado, tanto en el verano como durante el curso académico. Los resultados avalan el nivel de implicación de los es...

MODELO PARA LA GESTIÓN DEL CONOCIMIENTO ORGANIZACIONAL EN LA SUITE PARA LA DIRECCIÓN INTEGRADA POR PROYECTOS GESPRO

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Anisleiby Fernández Hernández

2014-06-01

Full Text Available La economía mundial se dirige hacia un nuevo modelo basado en el conocimiento, aportando ventajas competitivas gracias a su gestión. La Dirección Integrada por Proyectos requiere de la aplicación de un modelo para la gestión del conocimiento, con el objetivo de garantizar la elevación de la calidad de los nuevos proyectos. En el trabajo se presenta un modelo que combina y complementa diferentes estrategias para identificar, adquirir, retener, desarrollar y utilizar el conocimiento necesario en la realización de los proyectos, apoyadas por el uso de las Tecnologías de la Informática y las Comunicaciones. Este modelo responde y está en correspondencia con la versión 13.05 de la Suite para la Dirección Integrada por Proyectos Gespro de Software libre perteneciente a la Universidad de las Ciencias Informáticas, que se presenta como proceso para la gestión del conocimiento.

La forma en el proyecto urbano moderno

OpenAIRE

Ordóñez Alvarado, Wilson Paúl

2011-01-01

La forma en el proyecto urbano moderno nos introduce al análisis de la supercuadra de Brasilia, la misma que es considerada como el módulo base del planteamiento urbano de vivienda masiva en la modernidad. Se plantea la idea de una correspondencia existente entre la forma moderna expresada en el diseño y el planeamiento urbano, conceptos y pensamiento con los que el arquitecto Lucio Costa procedió a desarrollar el plan piloto con el que se concibió la nueva capital. Se presenta además un brev...

Action of UV-A and blue light on enzymes activity and accumulation of lipid peroxidation products in attached and detached frog retinas

Science.gov (United States)

Lapina, Victoria A.; Doutsov, Alexander E.

1994-07-01

The effect of the UV-A and blue light on the accumulation of lipid peroxidation products and activities of succinate dehydrogenase and superoxide dismutase in the retina was examined in eye cup model of dark and light adapted frogs R. temporaria. Retinas were exposed to UV-A radiation (8 mW/cm2) and blue light (10 to 150 mW/cm2) for periods from 5 min to 1 hr. We have measured TBA-active products both in the retina homogenates and in the reaction media. Enzyme activities was measured in the retina homogenates only. The measurements revealed a significant increase in the endogenous and exogenous forms of lipid peroxidation products in the retina of dark adapted frog (1.6+/- 0.4; 1.4+/- 0.3 nmole TBA-active products per mg protein, respectively) compared to light adapted (0.85+/- 0.16; 0.32+/- 0.06 nmole TBA-active products per mg protein, respectively). In the same conditions succinate dehydrogenase activity was decline more than 50% but superoxide dismutase activity didn't decrease. Disorganized inner and outer segments were observed after 40 min exposures. No light microscopic changes were detected after 5 min exposures. Light damage was significantly higher in the retina of dark adapted frog. The results indicate that the retina from eye cup of dark adapted frog is more susceptible to UV-A and blue light damages.

Early changes in retinal structure and BMP2 expression in the retina and crystalline lens of streptozotocin-induced diabetic pigs.

Science.gov (United States)

Jeong, Jae Seung; Lee, Woon-Kyu; Moon, Yeon Sung; Kim, Na Rae

2017-09-01

This study aims to evaluate early changes in retinal structure and BMP2 expression in the retina and crystalline lens by comparing streptozotocin-induced diabetic pigs and normal control group pigs. Five eye samples from five diabetic Micro-pigs (Medikinetics, Pyeongtaek, Korea) and five eye samples from five control pigs bred in a specific pathogen-free area were used. Diabetes was developed through intravenous injection of nicotinamide and streptozotocin, and the average fasting glucose level was maintained at 250 mg/dL or higher for 16 weeks. To evaluate BMP2 expression in the retina and crystalline lens, Western blotting was performed. In Hematoxylin and Eosin staining, most diabetic pigs showed structural abnormalities in the inner plexiform layer. The number of nuclei in the ganglion cell layer within the range of 10 4 µm 2 was 3.78±0.60 for diabetic pigs and 5.57±1.07 for control group pigs, showing a statistically significant difference. In immunohistochemical staining, diabetic retinas showed an overall increase in BMP2 expression. In Western blotting, the average BMP2/actin level of diabetic retinas was 1.19±0.05, showing a significant increase compared to the 1.06±0.03 of the control group retinas ( P =0.016). The BMP2/actin level of diabetic crystalline lenses was similar to the control group crystalline lenses ( P =0.730). Compared to control group pigs, the number of nuclei in the inner nuclear layer of retinas from streptozotocin-induced diabetic pigs decreased, while an increase in BMP2 expression was observed in the retina of diabetic pigs.

Design of a MEMS-based retina scanning system for biometric authentication

Science.gov (United States)

Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Schelinski, Uwe; Grüger, Heinrich

2014-05-01

There is an increasing need for reliable authentication for a number of applications such as e commerce. Common authentication methods based on ownership (ID card) or knowledge factors (password, PIN) are often prone to manipulations and may therefore be not safe enough. Various inherence factor based methods like fingerprint, retinal pattern or voice identifications are considered more secure. Retina scanning in particular offers both low false rejection rate (FRR) and low false acceptance rate (FAR) with about one in a million. Images of the retina with its characteristic pattern of blood vessels can be made with either a fundus camera or laser scanning methods. The present work describes the optical design of a new compact retina laser scanner which is based on MEMS (Micro Electric Mechanical System) technology. The use of a dual axis micro scanning mirror for laser beam deflection enables a more compact and robust design compared to classical systems. The scanner exhibits a full field of view of 10° which corresponds to an area of 4 mm2 on the retinal surface surrounding the optical disc. The system works in the near infrared and is designed for use under ambient light conditions, which implies a pupil diameter of 1.5 mm. Furthermore it features a long eye relief of 30 mm so that it can be conveniently used by persons wearing glasses. The optical design requirements and the optical performance are discussed in terms of spot diagrams and ray fan plots.

Synaptic Remodeling Generates Synchronous Oscillations in the Degenerated Outer Mouse Retina

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Wadood eHaq

2014-09-01

Full Text Available During neuronal degenerative diseases, neuronal microcircuits undergo severe structural alterations, leading to remodeling of synaptic connectivity. The functional consequences of such remodeling are mostly unknown. For instance, in mutant rd1 mouse retina, a common model for Retinitis Pigmentosa, rod bipolar cells (RBCs establish contacts with remnant cone photoreceptors (cones as a consequence of rod photoreceptor cell death and the resulting lack of presynaptic input. To assess the functional connectivity in the remodeled, light-insensitive outer rd1 retina, we recorded spontaneous population activity in retinal wholemounts using Ca2+ imaging and identified the participating cell types. Focusing on cones, RBCs and horizontal cells (HCs, we found that these cell types display spontaneous oscillatory activity and form synchronously active clusters. Overall activity was modulated by GABAergic inhibition from HCs. Many of the activity clusters comprised both cones and RBCs. Opposite to what is expected from the intact (wild-type cone-ON bipolar cell pathway, cone and RBC activity was positively correlated and, at least partially, mediated by glutamate transporters expressed on RBCs. Deletion of gap junctional coupling between cones reduced the number of clusters, indicating that electrical cone coupling plays a crucial role for generating the observed synchronized oscillations. In conclusion, degeneration-induced synaptic remodeling of the rd1 retina results in a complex self-sustained outer retinal oscillatory network, that complements (and potentially modulates the recently described inner retinal oscillatory network consisting of amacrine, bipolar and ganglion cells.

Uptake and release of [14C] GABA from rabbit retina synaptosomes

International Nuclear Information System (INIS)

Redburn, D.A.

1977-01-01

A partial separation of two synaptosomal fractions was achieved using modifications of conventional homogenization and centrifugation techniques. The two fractions contained morphologically distinct synaptosomal populations, receptor cell synaptosomes (large synaptosomes, P 1 ), and synaptosomes from the other cell types (smaller, conventional-sized synaptosomes, P 2 ). [ 14 C]GABA was bound and released from subcellular fractions from retina under conditions which support its role as a neurotransmitter in retina. On the other hand, [ 3 H]leucine, which is very likely a non-transmitter compound, was bound by retinal fractions but not released to the appropriate stimulation. [ 14 C]GABA binding and release sites were more prevalent in P 2 fractions. [ 14 C]GABA was bound by P 1 fractions containing photoreceptor synaptosomes; however, the K + stimulated release of [ 14 C]GABA appeared to be insensitive to external Ca 2+ . Possible mechanisms are discussed. (author)

Α-Melanocyte-Stimulating Hormone Protects Early Diabetic Retina from Blood-Retinal Barrier Breakdown and Vascular Leakage via MC4R.

Science.gov (United States)

Cai, Siwei; Yang, Qianhui; Hou, Mengzhu; Han, Qian; Zhang, Hanyu; Wang, Jiantao; Qi, Chen; Bo, Qiyu; Ru, Yusha; Yang, Wei; Gu, Zhongxiu; Wei, Ruihua; Cao, Yunshan; Li, Xiaorong; Zhang, Yan

2018-01-01

Blood-retinal barrier (BRB) breakdown and vascular leakage is the leading cause of blindness of diabetic retinopathy (DR). Hyperglycemia-induced oxidative stress and inflammation are primary pathogenic factors of this severe DR complication. An effective interventional modality against the pathogenic factors during early DR is needed to curb BRB breakdown and vascular leakage. This study sought to examine the protective effects of α-Melanocyte-stimulating hormone (α-MSH) on early diabetic retina against vascular hyperpermeability, electrophysiological dysfunction, and morphological deterioration in a rat model of diabetes and probe the mechanisms underlying the α-MSH's anti-hyperpermeability in both rodent retinas and simian retinal vascular endothelial cells (RF6A). Sprague Dawley rats were injected through tail vein with streptozotocin to induce diabetes. The rats were intravitreally injected with α-MSH or saline at Week 1 and 3 after hyperglycemia. In another 2 weeks, Evans blue assay, transmission electron microscopy, electroretinogram (ERG), and hematoxylin and eosin (H&E) staining were performed to examine the protective effects of α-MSH in diabetic retinas. The expression of pro-inflammatory factors and tight junction at mRNA and protein levels in retinas was analyzed. Finally, the α-MSH's anti-hyperpermeability was confirmed in a high glucose (HG)-treated RF6A cell monolayer transwell culture by transendothelial electrical resistance (TEER) measurement and a fluorescein isothiocyanate-Dextran assay. Universal or specific melanocortin receptor (MCR) blockers were also employed to elucidate the MCR subtype mediating α-MSH's protection. Evans blue assay showed that BRB breakdown and vascular leakage was detected, and rescued by α-MSH both qualitatively and quantitatively in early diabetic retinas; electron microscopy revealed substantially improved retinal and choroidal vessel ultrastructures in α-MSH-treated diabetic retinas; scotopic ERG suggested

The utilization of glutamine by the retina: an autoradiographic and metabolic study

International Nuclear Information System (INIS)

Voaden, M.J.; Lake, N.; Marshall, J.; Morjaria, B.

1978-01-01

The cells able to accumulate exogenously applied [ 3 H] glutamine in rat, cat, frog, pigeon and guinea pig retinas have been located by autoradiography, and the fate of the labelled glutamine, as regards its incorporation into aspartic, glutamic and γ-amino-butyric acids, followed for 60 min. The results support the notion of glutamine as a precursor of transmitter amino acids in some neurones. In particular, it would appear to be a source of a relatively stable pool of GABA which may be located, with species variation, in amacrine or ganglion cells. In the pigeon retina glutamate pool incorporates and retains a major percentage of the label, and perikarya in the middle of the inner nuclear layer of the tissue are predominantly labelled. (author)

EL PROYECTO ARKIT. LA VIVIENDA COMO KIT DE MUEBLES / Project Arkit. The home as a furniture kit

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Francisco Javier Terrados Cepeda

2012-05-01

Full Text Available RESUMEN El artículo hace una revisión sintética sobre algunas de las bases conceptuales del llamado “proyecto Arkit” así como sobre sus resultados en forma de proyectos residenciales y construcciones reales. Una primera parte recorre ejemplos de vivienda moderna donde lo que entendemos como mueble, levemente agigantado de escala, ha definido y en algunos casos realmente construido casi con exclusividad el espacio doméstico. Son los “muebles que construyen casas”. En la segunda parte, el artículo reseña los seis proyectos de casas prefabricadas ligeras que se han concebido al amparo del concepto del “kit de muebles” como sistema de prefabricación abierta: las viviendas del CSCAE, el prototipo Campohermoso, el proyecto Arkit, la residencia de Tariquejo, el proyecto Solarkit y el proyecto Arkit 18, de los cuales han sido construidos y analizados el tercero y el quinto: Arkit y su variante con energía solar Solarkit. El proyecto Arkit es una aportación novedosa en el campo de la vivienda prefabricada ligera, adaptada a las condiciones ambientales del sur de Europa, que usa como elementos constitutivos piezas de escala intermedia que están a medio camino entre el tamaño y la versatilidad del mobiliario y la escala de la habitación convencional. El proyecto Arkit permite disposiciones a elección del usuario y, como muestran los ejemplos expuestos, adaptaciones a diferentes programas residenciales. SUMMARY The article makes a summary review of some of the conceptual bases of the “ArtKit project” and their results as housing projects and real buildings. The first part covers examples of modern homes where what we understand as furniture, now rather gigantic in scale, has defined, and in some cases almost exclusively built, the domestic space. This is the “furniture which builds houses”. In the second part, the article reviews the six light prefabricated housing projects that have been designed under the �

Localization of glycine-containing neurons in the Macaca monkey retina

International Nuclear Information System (INIS)

Hendrickson, A.E.; Koontz, M.A.; Pourcho, R.G.; Sarthy, P.V.; Goebel, D.J.

1988-01-01

Autoradiography following 3H-glycine (Gly) uptake and immunocytochemistry with a Gly-specific antiserum were used to identify neurons in Macaca monkey retina that contain a high level of this neurotransmitter. High-affinity uptake of Gly was shown to be sodium dependent whereas release of both endogenous and accumulated Gly was calcium dependent. Neurons labeling for Gly included 40-46% of the amacrine cells and nearly 40% of the bipolars. Synaptic labeling was seen throughout the inner plexiform layer (IPL) but with a preferential distribution in the inner half. Bands of labeled puncta occurred in S2, S4, and S5. Both light and postembedding electron microscopic (EM) immunocytochemistry identified different types of amacrine and bipolar cell bodies and their synaptic terminals. The most heavily labeled Gly+ cell bodies typically were amacrine cells having a single, thick, basal dendrite extending deep into the IPL and, at the EM level, electron-dense cytoplasm and prominent nuclear infoldings. This cell type may be homologous with the Gly2 cell in human retina and the AII/Gly2 of cat retina. Gly+ amacrines synapse most frequently onto Gly- amacrines and both Gly- and Gly+ bipolars. Gly+ bipolar cells appeared to be cone bipolars because their labeled dendrites could be traced only to cone pedicles. The pattern of these labeled dendritic trees indicated that both diffuse and midget types of biopolars were Gly+. The EM distribution of labeled synapses showed Gly+ amacrine synapses throughout the IPL, but these composed only 11-23% of the amacrine population. Most of the Gly+ bipolar terminals were in the inner IPL, where 70% of all bipolar terminals were labeled

Assessment of apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy after grape polyphenols intervention

Institute of Scientific and Technical Information of China (English)

Sheng-Li Zhang

2016-01-01

Objective:To study the effect of grape polyphenols intervention on apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy (DR).Methods: SPF male SD rats were selected as experimental animals and divided into control group, diabetes group and grape polyphenols group, intraperitoneal injection of streptozotocin was adopted to establish diabetic rat models, and grape polyphenols group received intragastric administration of grape polyphenols. 60 d after model establishment, the rats were executed, and the retina tissue was collected to determine apoptosis molecules and oxidative stress indexes.Results:Bax, Caspase-3, c-fos, c-jun, ROS, MDA, 8-OHdG, PARP, Cyclophilin D, Nrf-2, ARE, ERK and PI3K content in retina tissue of diabetes group were significantly higher than those of control group while Bcl-2, CAT, SOD, GSH-Px, HO-1 and NQO1 content were significantly lower than those of control group; Bax, Caspase-3, c-fos, c-jun, ROS, MDA, 8-OHdG, PARP and Cyclophilin D content in retina tissue of grape polyphenols group were significantly lower than those of diabetes group while Bcl-2, CAT, SOD, GSH-Px, HO-1, NQO1, Nrf-2, ARE, ERK and PI3K content were significantly higher those of diabetes group.Conclusions:Grape polyphenols intervention can relieve the apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy.

Spatial organization of lipids in the human retina and optic nerve by MALDI imaging mass spectrometry.

Science.gov (United States)

Zemski Berry, Karin A; Gordon, William C; Murphy, Robert C; Bazan, Nicolas G

2014-03-01

MALDI imaging mass spectrometry (IMS) was used to characterize lipid species within sections of human eyes. Common phospholipids that are abundant in most tissues were not highly localized and observed throughout the accessory tissue, optic nerve, and retina. Triacylglycerols were highly localized in accessory tissue, whereas sulfatide and plasmalogen glycerophosphoethanolamine (PE) lipids with a monounsaturated fatty acid were found enriched in the optic nerve. Additionally, several lipids were associated solely with the inner retina, photoreceptors, or retinal pigment epithelium (RPE); a plasmalogen PE lipid containing DHA (22:6), PE(P-18:0/22:6), was present exclusively in the inner retina, and DHA-containing glycerophosphatidylcholine (PC) and PE lipids were found solely in photoreceptors. PC lipids containing very long chain (VLC)-PUFAs were detected in photoreceptors despite their low abundance in the retina. Ceramide lipids and the bis-retinoid, N-retinylidene-N-retinylethanolamine, was tentatively identified and found only in the RPE. This MALDI IMS study readily revealed the location of many lipids that have been associated with degenerative retinal diseases. Complex lipid localization within retinal tissue provides a global view of lipid organization and initial evidence for specific functions in localized regions, offering opportunities to assess their significance in retinal diseases, such as macular degeneration, where lipids have been implicated in the disease process.

Desarrollo de un modelo de evaluación financiera de proyectos para BAC Credomatic Network

OpenAIRE

Sandí Piedra, Allan Adolfo

2016-01-01

Universidad de Costa Rica. Posgrado en Administración y Dirección de Empresas. Maestría Profesional en Administración y Dirección de Empresas con énfasis en Finanzas, 2016 El presente trabajo final de investigación contiene los aspectos que fundamentan un modelo de Evaluación Financiera de Proyectos que permite solventar la problemática identificada en BAC Credomatic Network respecto al limitado valor agregado del proceso existente de valoración financiera de los proyectos de la empresa. P...

Estado del arte: relación entre la estrategia organizacional y el portafolio de proyectos

OpenAIRE

Torres Villegas, Margarita Cecilia

2016-01-01

El presente estado del arte se orienta a relacionar los aportes más notables que se han registrado en los temas de la estrategia organizacional y el portafolio de proyectos, además de establecer la relación existente entre los dos conceptos; para ello se tomó como base documental, las recientes publicaciones en revistas, testimonios e investigaciones, y los datos de centros de investigación universitaria, también se incluyeron trabajos de grado en las maestría en gerencia de proyectos, en adm...

Guía para la elaboración de proyectos de instalaciones en locales comerciales

OpenAIRE

Sánchez Rodríguez, Carlos

2013-01-01

El objeto del presente proyecto, es la realización de un resumen de las instalaciones y documentos técnicos aplicados para la realización de proyectos de instalaciones en locales comerciales. La estructura del trabajo se ha planteado de la siguiente forma: Bloque 1: Recordatorio de conceptos básicos de los tipos de trámites más habituales en locales comerciales. Clasificación de las actividades según la ley de Prevención y control ambiental de las actividades. Resumen de los pr...

Seguimiento de proyectos de programación. Una aplicación de GitHub en la educación

OpenAIRE

Javier Salazar Zárate; Blanca Hidalgo Ponce; Narcisa Salazar Alvarez; Byron Vaca Barahona

2016-01-01

Esta investigación desarrolla y propone un método para la ejecución y se-guimiento de los proyectos de fin de curso de las materias de lenguajes de programación en carreras de Ingeniería Electrónica soportado tecnológica-mente por GitHub. El objetivo es obtener un método que permita mejorar la calidad de los proyectos. Para la validación del nuevo método se realiza un contraste entre dos grupos de estudiantes, el primer grupo utilizando el mé-todo tradicional de ejecución de proyectos y el se...

Abnormal levels of histone methylation in the retinas of diabetic rats are reversed by minocycline treatment

DEFF Research Database (Denmark)

Wang, Wenjun; Sidoli, Simone; Zhang, Wenquan

2017-01-01

67% of these marks had their relative abundance restored to non-diabetic levels after minocycline treatment. Mono-and di-methylation states of histone H4 lysine 20 (H4K20me1/me2), markers related to DNA damage response, were found to be up-regulated in the retinas of diabetic rats and restored......In this study we quantified the alterations of retinal histone post-translational modifications (PTMs) in diabetic rats using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach. Some diabetic rats were subsequently treated with minocycline, a tetracycline antibiotic, which has...... been shown to inhibit the diabetes-induced chronic inflammation in the retinas of rodents. We quantified 266 differentially modified histone peptides, including 48 out of 83 methylation marks with significantly different abundancein retinas of diabetic rats as compared to non-diabetic controls. About...

Cytogenesis in the monkey retina

International Nuclear Information System (INIS)

La Vail, M.M.; Rapaport, D.H.; Rakic, P.

1991-01-01

Time of cell origin in the retina of the rhesus monkey (Macaca mulatta) was studied by plotting the number of heavily radiolabeled nuclei in autoradiograms prepared from 2- to 6-month-old animals, each of which was exposed to a pulse of 3H-thymidine (3H-TdR) on a single embryonic (E) or postnatal (P) day. Cell birth in the monkey retina begins just after E27, and approximately 96% of cells are generated by E120. The remaining cells are produced during the last (approximately 45) prenatal days and into the first several weeks after birth. Cell genesis begins near the fovea, and proceeds towards the periphery. Cell division largely ceases in the foveal and perifoveal regions by E56. Despite extensive overlap, a class-specific sequence of cell birth was observed. Ganglion and horizontal cells, which are born first, have largely congruent periods of cell genesis with the peak between E38 and E43, and termination around E70. The first labeled cones were apparent by E33, and their highest density was achieved between E43 and E56, tapering to low values at E70, although some cones are generated in the far periphery as late as E110. Amacrine cells are next in the cell birth sequence and begin genesis at E43, reach a peak production between E56 and E85, and cease by E110. Bipolar cell birth begins at the same time as amacrines, but appears to be separate from them temporally since their production reaches a peak between E56 and E102, and persists beyond the day of birth. Mueller cells and rod photoreceptors, which begin to be generated at E45, achieve a peak, and decrease in density at the same time as bipolar cells, but continue genesis at low density on the day of birth. Thus, bipolar, Mueller, and rod cells have a similar time of origin

MEMS scanner mirror based system for retina scanning and in eye projection

Science.gov (United States)

Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Dallmann, Hans-Georg; Schelinski, Uwe; Grüger, Heinrich

2015-02-01

Many applications could benefit from miniaturized systems to scan blood vessels behind the retina in the human eye, so called "retina scanning". This reaches from access control to sophisticated security applications and medical devices. High volume systems for consumer applications require low cost and a user friendly operation. For example this includes no need for removal of glasses and self-adjustment, in turn guidance of focus and point of attraction by simultaneous projection for the user. A new system has been designed based on the well-known resonantly driven 2-d scanner mirror of Fraunhofer IPMS. A combined NIR and VIS laser system illuminates the eye through an eye piece designed for an operating distance allowing the use of glasses and granting sufficient field of view. This usability feature was considered to be more important than highest miniaturization. The modulated VIS laser facilitates the projection of an image directly onto the retina. The backscattered light from the continuous NIR laser contains the information of the blood vessels and is detected by a highly sensitive photo diode. A demonstrational setup has been realized including readout and driving electronics. The laser power was adjusted to an eye-secure level. Additional security features were integrated. Test measurements revealed promising results. In a first demonstration application the detection of biometric pattern of the blood vessels was evaluated for issues authentication in.

Neurite regeneration in adult rat retinas exposed to advanced glycation end-products and regenerative effects of neurotrophin-4.

Science.gov (United States)

Bikbova, Guzel; Oshitari, Toshiyuki; Yamamoto, Shuichi

2013-10-09

The purpose of this study was to determine the effect of low concentrations of advanced glycation end-products on neurite regeneration in isolated rat retinas, and to determine the effects of neurotrophin-4 on regeneration in advanced glycation end-products exposed retinas. Retinal explants of 4 adult Sprague-Dawley rats were cultured on collagen gel and were incubated in; (1) serum-free control culture media, (2) glucose-advanced glycation end-products-bovine serum albumin media, (3) glycolaldehyde-advanced glycation end-products-bovine serum albumin media, (4) glyceraldehyde-advanced glycation end-products-bovine serum albumin media, (5) glucose-advanced glycation end-products+neurotrophin-4 media, (6) glycolaldehyde-advanced glycation end-products+neurotrophin-4 media, or (7) glyceraldehyde-advanced glycation end-products+neurotrophin-4 supplemented culture media. After 7 days, the number of regenerating neurites from the explants was counted. Then, explants were fixed, cryosectioned, and stained for TUNEL. The ratio of TUNEL-positive cells to all cells in the ganglion cell layer was determined. Immunohistochemical examinations for the active-form of caspase-9 and apoptosis-inducing factor were performed. In retinas incubated with advanced glycation end-products containing media, the number of regenerating neurites were fewer than in retinas without advanced glycation end-products, and the number of TUNEL-positive cells and caspase-9- and apoptosis-inducing factor-immunopositive cells was significantly higher than in control media. Neurotrophin-4 supplementation increased the numbers of regenerating neuritis, and the number of TUNEL-positives, caspase-9-, and apoptosis-inducing factor-immunopositive cells were significantly fewer than that in advanced glycation end-products without neurotrophin-4 media. Low doses of advanced glycation end-products impede neurite regeneration in the rat retinas. Neurotrophin-4 significantly enhances neurite regeneration in

Los proyectos de cooperación: una alternativa al tiempo libre de alumnos universitarios

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Beatriz Núñez Angulo

2014-12-01

Full Text Available Es sabido por todos que la Universidad ha de fomentar los Proyectos de Cooperación, como función social. Presentamos la trayectoria de un proyecto de Cooperación al Desarrollo de la Universidad de Burgos que, a lo largo de 10 años se ha ido consolidando y ha permitido la participación directa de 88 personas entre profesores y alumnos, siendo una alternativa al tiempo libre del alumnado, tanto en el verano como durante el curso académico. Los resultados avalan el nivel de implicación de los estudiantes a través de las actividades realizadas en los países de destino como en España. Se destaca el elevado número de personas que han asistido a sus conferencias de sensibilización, así como los recursos materiales y espacios que se ha logrado  financiar a través de diferentes actividades integradas en el proyecto. A todo ello hay que añadir el alto de grado de satisfacción de la Comunidad Universitaria  y de las entidades destinatarias.

Heat shock protein 70 and heat shock protein 90 expression in light- and dark-adapted adult octopus retinas.

Science.gov (United States)

Ochoa, Gina H; Clark, Ying Mei; Matsumoto, Brian; Torres-Ruiz, Jose A; Robles, Laura J

2002-02-01

Light- and dark-adaptation leads to changes in rhabdom morphology and photopigment distribution in the octopus retina. Molecular chaperones, including heat shock proteins (Hsps), may be involved in specific signaling pathways that cause changes in photoreceptor actin- and tubulin-based cytoskeletons and movement of the photopigments, rhodopsin and retinochrome. In this study, we used immunoblotting, in situ RT-PCR, immunofluorescence and confocal microscopy to localize the inducible form of Hsp70 and the larger Hsp90 in light- and dark-adapted and dorsal and ventral halves of adult octopus retinas. The Hsps showed differences in distribution between the light and dark and in dorsal vs. ventral position in the retina. Double labeling confocal microscopy co-localized Hsp70 with actin and tubulin, and Hsp90 with the photopigment, retinochrome. Our results demonstrate the presence of Hsp70 and Hsp90 in otherwise non-stressed light- and dark-adapted octopus retinas. These Hsps may help stabilize the cytoskeleton, important for rhabdom structure, and are perhaps involved in the redistribution of retinochrome in conditions of light and dark.

Distribution of light in the human retina under natural viewing conditions

Science.gov (United States)

Gibert, Jorge C.

Age-related macular degeneration (AMD) is the leading cause of blindness inAmerica. The fact that AMD wreaks most of the damage in the center of the retina raises the question of whether light, integrated over long periods, is more concentrated in the macula. A method, based on eye-tracking, was developed to measure the distribution of light in the retina under natural viewing conditions. The hypothesis was that integrated over time, retinal illumination peaked in the macula. Additionally a possible relationship between age and retinal illumination was investigated. The eye tracker superimposed the subject's gaze position on a video recorded by a scene camera. Five informed subjects were employed in feasibility tests, and 58 naive subjects participated in 5 phases. In phase 1 the subjects viewed a gray-scale image. In phase 2, they observed a sequence of photographic images. In phase 3 they viewed a video. In phase 4, they worked on a computer; in phase 5, the subjects walked around freely. The informed subjects were instructed to gaze at bright objects in the field of view and then at dark objects. Naive subjects were allowed to gaze freely for all phases. Using the subject's gaze coordinates, and the video provided by the scene camera, the cumulative light distribution on the retina was calculated for ˜15° around the fovea. As expected for control subjects, cumulative retinal light distributions peaked and dipped in the fovea when they gazed at bright or dark objects respectively. The light distribution maps obtained from the naive subjects presented a tendency to peak in the macula for phases 1, 2, and 3, a consistent tendency in phase 4 and a variable tendency in phase 5. The feasibility of using an eye-tracker system to measure the distribution of light in the retina was demonstrated, thus helping to understand the role played by light exposure in the etiology of AMD. Results showed that a tendency for light to peak in the macula is a characteristic of some

Estudio comparativo del mercado de las herramientas de gestión de proyectos informáticos

OpenAIRE

Martínez Dufau, Alejandro Gabriel

2012-01-01

El presente estudio se centra en la gestión de proyectos. Dentro de este ámbito el estudio girará entorno a las herramientas de gestión de proyectos que actualmente hay en el mercado destinadas a las grandes empresas. Aquest estudi se centra en la gestió de projectes. Dins d'aquest àmbit l'estudi girarà entorn a les eines de gestió de projectes que actualment hi ha al mercat destinades a les grans empreses.

Neuroprotective effect of bilberry extract in a murine model of photo-stressed retina.

Directory of Open Access Journals (Sweden)

Hideto Osada

Full Text Available Excessive exposure to light promotes degenerative and blinding retinal diseases such as age-related macular degeneration and retinitis pigmentosa. However, the underlying mechanisms of photo-induced retinal degeneration are not fully understood, and a generalizable preventive intervention has not been proposed. Bilberry extract is an antioxidant-rich supplement that ameliorates ocular symptoms. However, its effects on photo-stressed retinas have not been clarified. In this study, we examined the neuroprotective effects of bilberry extract against photo-stress in murine retinas. Light-induced visual function impairment recorded by scotopic and phototopic electroretinograms showing respective rod and cone photoreceptor function was attenuated by oral administration of bilberry extract through a stomach tube in Balb/c mice (750 mg/kg body weight. Bilberry extract also suppressed photo-induced apoptosis in the photoreceptor cell layer and shortening of the outer segments of rod and cone photoreceptors. Levels of photo-induced reactive oxygen species (ROS, oxidative and endoplasmic reticulum (ER stress markers, as measured by real-time reverse transcriptase polymerase chain reaction, were reduced by bilberry extract treatment. Reduction of ROS by N-acetyl-L-cysteine, a well-known antioxidant also suppressed ER stress. Immunohistochemical analysis of activating transcription factor 4 expression showed the presence of ER stress in the retina, and at least in part, in Müller glial cells. The photo-induced disruption of tight junctions in the retinal pigment epithelium was also attenuated by bilberry extract, repressing an oxidative stress marker, although ER stress markers were not repressed. Our results suggest that bilberry extract attenuates photo-induced apoptosis and visual dysfunction most likely, and at least in part, through ROS reduction, and subsequent ER stress attenuation in the retina. This study can help understand the mechanisms of photo

Finestructure of the retina in Garra rufa (cypriniae, Teleostei)

International Nuclear Information System (INIS)

Al-Adhami, A. M.; Mir, S.

1999-01-01

The light - and dark-adapted retina of the freshwater, bottom-dweller tele ost, Ga rra rufa (Heck el, 1843) was studied under light and electron microscopes. The fish is a fist record in having both falcifrom process and vit real blood circulation and the hyaloid artery from which it developers. A number of acute vision areas represented by increased density of ganglion cell soma ta are evident. The dark-adapted retina is characterized by notably large photoreceptor terminals (rod spherules and cone placidas). A rod spherules has single synaptic ribbon, whereas a cone pedicle has three to four. The inner nuclear layer is composed of the so meta of horizontal, bipolar and amsacrine cells in addition to nuclei of Muller cells. The outer nuclear layer, on the other hand, is composed of two-three rows of rod nuclei and one row of cone nuclei. The photoreceptor cells include rods and single and double cones. The rod outer segments have deep and/or shallow incisor. Cone ellipsoid may have ellipsosomes. These are shown to develop from one of the apical mitochondria of the ellipsoid- Retinomotor movement involves both the photoreceptor cells and the pigment epithelium. (authors). 11 refs., 14 figs

Msx1 is expressed in retina endothelial cells at artery branching sites

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Miguel Lopes

2012-02-01

Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1lacZ is expressed in vascular smooth muscle cells (VSMCs and pericytes, and that Msx2lacZ is also expressed in VSMCs as well as in a few endothelial cells (ECs. The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1lacZ and Msx2lacZ reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1lacZ is expressed more broadly and dynamically. At birth Msx1lacZ expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.

Msx1 is expressed in retina endothelial cells at artery branching sites.

Science.gov (United States)

Lopes, Miguel; Goupille, Olivier; Saint Cloment, Cécile; Robert, Benoît

2012-04-15

Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1(lacZ) is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2(lacZ) is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1(lacZ) and Msx2(lacZ) reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1(lacZ) is expressed more broadly and dynamically. At birth Msx1(lacZ) expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.

LA CULTURA EMPRENDEDORA Y LOS PROYECTOS FINANCIADOS

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Rodolfo Ramírez Calvillo

2013-06-01

Full Text Available En el presente estudio se analizan los proyectos productivos apoyados por el Programa 3x1 Para Migrantes en Zacatecas durante el periodo 2002-2007 a fin de determinar dentro del concepto de cultura emprendedora la identificación del giro en que les agradaría emprender a los líderes de los proyectos productivos  y  reconocer el perfil de los emprendedores.Se seleccionó el enfoque de métodos mixtos porque tiende a concepciones pragmáticas del conocimiento. Recurre a preguntas abiertas y cerradas, enfoques emergentes y predeterminados,  datos y los respectivos análisis (Creswell, 2003.La estrategia de indagación que se utilizó fue la secuencial exploratoria, debido a sus características, en la obtención y análisis de los datos cualitativos, seguida por la obtención y análisis de los datos cuantitativos.Los resultados fue que la gran mayoría desea continuar con la actividad en la que actualmente  está trabajando y el nuevo emprendimiento consolidaría su actual situación, emprenderían  en otra rama como la agricultura controlada como el caso del invernadero para evitar las adversidades climatológicas, o como el caso de la fruticultura, el avanzar hacia la envasadora de frutas y las conservas.No hay un solo perfil sino una diversidad con ciertos rasgos característicos propios del entorno del estado de Zacatecas. 

Microscopic hyperspectral imaging studies of normal and diabetic retina of rats

Institute of Scientific and Technical Information of China (English)

2008-01-01

A microscopic hyperspectral imager was developed based on the microscopic technology and the spectral imaging technology. Some microscopic hyperspectral images of retina sections of the normal, the diabetic, and the treated rats were collected by the new imager. Single-band images and pseudo-color images of each group were obtained and the typical transmittance spectrums were ex-tracted. The results showed that the transmittance of outer nuclear layer cells of the diabetic group was generally higher than that of the normal. A small absorption peak appeared near the 180th band in the spectrum of the diabetic group and this peak weakened or disappeared in the spectrum of the treated group. Our findings indicate that the microscopic hyperspectral images include wealthy information of retina sections which is helpful for the ophthalmologist to reveal the pathogenesis of diabetic reti-nopathy and explore the therapeutic effect of drugs.

[Expression of vimentin and GFAP and development of the retina in the trout].

Science.gov (United States)

De Guevara, R; Pairault, C; Pinganaud, G

1994-08-01

The glial cell development was studied during the edification of the retina and the optic tract, in a teleost, the rainbow trout. The intermediate filament proteins, vimentin and glial fibrillary acidic protein (GFAP) were visualized by an indirect immunohistochemical method. Results show that both vimentin and GFAP are early expressed in the developing retina and, particularly in the Müller cells, a coexpression of vimentin and GFAP is observed from embryonic to adult stages. The ganglion cell layer and the optic fiber layer both exhibit GFAP-positive structures. The deep staining for GFAP is also seen in the optic nerve and induces us to credit astrocyte-like cells with a leading role in the pattern formation of this tract.

La inflación y las tasas de retorno en los proyectos de inversión

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Henry Carmona Velez

1989-04-01

Full Text Available RESUMEN El autor  plantea en el presente artículo la necesidad de incluir el proceso inflacionario en todos aquellos factores que intervienen en el presupuesto de capital, y más específicamente en aquellos que inicien en la toma de decisiones y directamente relacionados con los proyectos  de inversión. Se destaca en el artículo la tendencia, muy generalizada, de soslayar los cambios  en los niveles  de precios, en la determinación  de los flujos  de los proyectos y la evaluación  de los mismos. La alternativa planteada, en consecuencia, considera que si bien es incuestionable  la existencia  de la inflación, también deberá ser que  los probables efectos de la misma sean cuantificados e incluidos  en los cálculos inherentes  a la determinación   de los flujos o retornos del proyecto.

Curso CC 2010: Sobre proyectos de cultura científica

OpenAIRE

Ferrando González, Laura; Martínez Cáceres, Rafael

2010-01-01

Breves apuntes sobre los proyectos de cultura científica, su estructura y elementos, elaborados en el marco del curso de formación "Cultura científica: divulgación y comunicación de la ciencia", organizado por la Vicepresidenta Adjunta de Organización y Cultura Científica para personal del CSIC.

Mechanical Stress and Antioxidant Protection in the Retina of Hindlimb Suspended Rats

Science.gov (United States)

Glass, Aziza; Theriot, Corey A.; Alway, Stephen E.; Zanello, Susana B.

2012-01-01

It has been postulated that hindlimb suspension (HS) causes a cephalad fluid shift in quadrupeds similar to that occurring to humans in microgravity. Therefore, HS may provide a suitable animal model in which to recapitulate the ocular changes observed in the human Visual Impairment and Intracranial Pressure (VIIP) syndrome. This work reports preliminary results from a tissue sharing project using 34 week-old Brown Norway rats. Two different experiments compared normal posture controls and HS rats for 2 weeks and rats exposed to HS for 2 weeks but allowed to recover in normal posture for 2 additional weeks. The effects of two nutritional countermeasures, green tea extract (GT) and plant polyphenol resveratrol (Rv), were also evaluated. Green tea contains the antioxidant epigallocatechin gallate (EGCG). qPCR gene expression analysis of selected targets was performed on RNA from isolated retinas, and histologic analysis was done on one fixed eye per rat. The transcription factor early growth response protein 1 (Egr1) was upregulated almost 2-fold in HS retinas relative to controls (P = 0.059), and its expression returned to control levels after 2 weeks of recovery in normal posture (P = 0.023). HS-induced upregulation of Egr1 was attenuated (but not significantly) in retinas from rats fed an antioxidant rich (GT extract) diet. In rats fed the GT-enriched diet, antioxidant enzymes were induced, evidenced by the upregulation of the gene heme oxygenase 1 (Hmox1) (P = 0.042) and the gene superoxide dismutase 2 (Sod2) (P = 0.0001). Egr1 is a stretch-activated transcription factor, and the Egr1 mechanosensitive response to HS may have been caused by a change in the translaminal pressure and/or mechanical deformation of the eye globe. The observed histologic measurements of the various retinal layers in the HS rats were lower in value than those of the control animal (n = 1), however insufficient data were available for statistical analysis. Aquaporin 4, a water

Algunos dibujos de la primera arquitectura de Nueva España: mapas, planos y proyectos de arquitectura del siglo XVI

OpenAIRE

Moya Olmedo, Pilar

2014-01-01

Moya Olmedo, P. (2014). Algunos dibujos de la primera arquitectura de Nueva España: mapas, planos y proyectos de arquitectura del siglo XVI. P+C: proyecto y ciudad: revista de temas de arquitectura (5), 75-88. ISSN 2172-9220 (ISOC; LATINDEX; DIALNET; RESH; DICE; MIAR)

Análisis y Evaluación de Programas Universitarios para Mayores. Informe Final Proyecto Investigación AEPUMA 116/0

OpenAIRE

Bru Ronda, Concepción; Argente del Castillo Ocaña, Concepción; Arnay Puerta, José; Bonete López, Beatriz; Cabedo Manuel, Salvador; Cordero del Castillo, Prisciliano; Domínguez Almellones, María Auxiliadora; Escuder Mollón, Pilar; Fernández Ballesteros, Rocío; Hernández Pedreño, Manuel; Holgado Sánchez, María Adoración; Jiménez Erguizabal, Juan Alfredo; Jiménez Rodríguez, Raquel; López Blanes, Antonio; Lorenzo Vicente, Juan Antonio

2007-01-01

Análisis y Evaluación de Programas Universitarios para Mayores. MINISTERIO DE TRABAJO Y ASUNTOS SOCIALES, Informe Final del proyecto AEPUM (Cod. proyecto 116/2005). Convocatoria I+D+I de la Subdirección general de planificación, ordenación y evaluación del IMSERSO. Pag. 782. El documento que se publica es el Informe Final y resultado del proyecto realizado entre 2005 y 2007 por 19 Universidades y Programas Universitarios para Mayores en España y correspondiente al trabajo desarrollado en ...

Radicals excess in the retina: A model for light flashes in space

International Nuclear Information System (INIS)

Narici, L.; De Martino, A.; Brunetti, V.; Rinaldi, A.; Sannita, W.G.; Paci, M.

2009-01-01

The risk due to cosmic radiation is a major issue in planning future missions to the Moon or Mars and would be critical if inadequately addressed. Functional risks must also be considered. The perception of light flashes reported by astronauts in space, and ascribed mostly to the action of ionizing radiation in the eye (retina), is an evidence for radiation functional interaction. No detailed model of the ion/retina interaction is yet available. Here we present the first model for a generation mechanism compatible with light flashes in space, and the results of in vitro tests supporting it. The model can be a common end point for the interactions between ionizing radiation and visual system in space. It would also support the assessment of functional radiation risks in space.

Ontogenetic expression of the Otx2 and Crx homeobox genes in the retina of the rat

DEFF Research Database (Denmark)

Rath, Martin F; Morin, Fabrice; Shi, Qiong

2007-01-01

. This confirmed the presence of Otx2 mRNA in both the embryonic retinal pigment epithelium and the developing neural retina. During development, the expression of Otx2 persists in the pigment epithelium, whereas Otx2 expression of the neural retina becomes progressively restricted to the outer nuclear layer......Otx2 and Crx are vertebrate orthologs of the orthodenticle family of homeobox genes, which are involved in retinal development. In this study, the temporal expression patterns of Otx2 and Crx in the rat retina during embryonic and postnatal stages of development were analyzed in detail...... and the outer part of the inner nuclear layer. Immunohistochemistry revealed that Otx2 protein is also present in cell bodies of the ganglion cell layer, which does not contain the Otx2 transcript, suggesting that Otx2 protein is synthesized in cell bodies of the bipolar neurons and then transported...

The Endocannabinoid System in the Retina: From Physiology to Practical and Therapeutic Applications

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Thomas Schwitzer

2016-01-01

Full Text Available Cannabis is one of the most prevalent drugs used in industrialized countries. The main effects of Cannabis are mediated by two major exogenous cannabinoids: ∆9-tetrahydroxycannabinol and cannabidiol. They act on specific endocannabinoid receptors, especially types 1 and 2. Mammals are endowed with a functional cannabinoid system including cannabinoid receptors, ligands, and enzymes. This endocannabinoid signaling pathway is involved in both physiological and pathophysiological conditions with a main role in the biology of the central nervous system. As the retina is a part of the central nervous system due to its embryonic origin, we aim at providing the relevance of studying the endocannabinoid system in the retina. Here, we review the distribution of the cannabinoid receptors, ligands, and enzymes in the retina and focus on the role of the cannabinoid system in retinal neurobiology. This review describes the presence of the cannabinoid system in critical stages of retinal processing and its broad involvement in retinal neurotransmission, neuroplasticity, and neuroprotection. Accordingly, we support the use of synthetic cannabinoids as new neuroprotective drugs to prevent and treat retinal diseases. Finally, we argue for the relevance of functional retinal measures in cannabis users to evaluate the impact of cannabis use on human retinal processing.

Instalaciones eléctricas en edificios de viviendas. Proyecto de un edificio.

OpenAIRE

Sánchez Rodríguez, Juan Manuel; Cárcel Carrasco, Francisco Javier

2015-01-01

Sánchez Rodríguez, JM.; Cárcel Carrasco, FJ. (2015). Instalaciones eléctricas en edificios de viviendas. Proyecto de un edificio. Area de Innovación y Desarrollo S.L. http://hdl.handle.net/10251/83665 Senia

Valuación financiera de proyectos de inversión en nuevas tecnologías con opciones reales

Directory of Open Access Journals (Sweden)

Francisco Antonio Álvarez Echeverría

2012-01-01

Full Text Available La valuación financiera de proyectos de inversión que involucran nuevas tecnologías requiere de cierto grado de flexibilidad en la implementación de estrategias futuras de negocio como son la expansión, contracción, posposición y abandono del proyecto; asimismo, incorporar la creciente incertidumbre que presentan las nuevas tecnologías a través de tasas de descuento que tengan una dinámica estocástica y que pueden ser simuladas con diversos modelos de tasas de interés como el de Vasicek y CIR que permiten hacer escenarios alternos para evaluar un proyecto de inversión. En este trabajo se desarrolla y aplica la metodología de opciones reales para la adopción de una tecnología del tipo Wi-Fi; para ello se considera una opción real de expansión con el objeto de estimar los flujos de efectivo esperados, así como la rentabilidad del proyecto dentro de un intervalo de tiempo determinado en comparación con la técnica tradicional del valor presente neto (VPN. La tasa de descuento utilizada en la valuación se desprende de la estructura de plazos estimada mediante los modelos Vasicek (1977 y CIR (1985. Los resultados de la valuación reflejan que desde el tercer periodo los flujos de efectivo con opciones reales son positivos, mientras que el VPN lo hace hasta el séptimo periodo, situación que incrementa la probabilidad de tener un VPN negativo que rechace el proyecto, a pesar de que éste tiene viabilidad financiera, si incorporamos el valor de la flexibilidad en el proyecto, el cual no es cuantificado por las técnicas tradicional como el VPN; por lo tanto, se debe complementar el análisis incluyendo una opción real.

Proyecto Energético Palmdale; Decisión del Permiso Final

Science.gov (United States)

Proyecto Energético Palmdale: EPA Región 9 por el presente emite aviso de su decisión final, el cumplimiento con la Ley Federal de Aire Limpio, para la construcción de una planta generadora de electricidad de ciclo combinado y alimentada por gas natural

Una propuesta de aprendizaje por proyectos en el aula de Español de Negocios

OpenAIRE

Iolanda Nieves de la Vega

2016-01-01

Este artículo tiene como objetivo mostrar las ventajas del aprendizaje por proyectos (APP) como herramienta metodológica en el marco de un curso de Español de Negocios, compartir con otros docentes el planteamiento teórico y el proceso de creación de un proyecto a partir de la realización de un «estudio de mercado» y hacer una serie de consideraciones prácticas que favorezcan la implicación de los estudiantes en la realización de un trabajo cooperativo y la toma de consciencia de la relevanci...

Possible influences of lutein and zeaxanthin on the developing retina.

Science.gov (United States)

Zimmer, J Paul; Hammond, Billy R

2007-03-01

The carotenoids lutein and zeaxanthin (LZ) are found throughout the central nervous system but reach their highest concentration within the macular region of the primate retina where they are commonly referred to as the macular pigments. Although LZ are a major integral feature of the central fovea, no information currently exists regarding the effects of variability in the concentration of these pigments on the developing retina. In particular, the long-term effects of very low levels of macular pigment are not known and potentially meaningful. Macular pigment levels depend upon dietary intake since LZ cannot be synthesized de novo. Infants with low intake of LZ (eg, infants receiving unfortified infant formula or breast milk from mothers with low carotenoid diets) would be expected to have considerably lower macular pigment compared with infants with high LZ intake (eg, breast-fed infants with mothers on carotenoid-rich diets). In this paper we discuss possible implications of this difference and the available evidence suggesting that LZ could influence the developing visual system.

Changes in acetylcholine release from the chick retina are not associated with myopia development

International Nuclear Information System (INIS)

Vessey, K.A.; Cotriall, C.L.; McBrien, N.A.

2002-01-01

Full text: The effectiveness of muscarinic receptor antagonists in inhibiting myopia progression in animal models and humans implicates cholinergic signalling in ocular growth regulation. Therefore to determine if changes in the release of acetylcholine from the retina are involved in myopia development, the efflux of acetylcholine from the in vitro retina of normal and myopic chick eyes was investigated. Chicks were monocularly deprived (MD) of pattern vision with translucent occluders for 2 or 7 days and refractive error of MD groups and age matched normals was monitored using retinoscopy (n=6 each group). 3 H-choline-Cl (1 Ci in 7μL) was injected into the vitreous of each eye under 2.5% halothane anaesthesia. After 1hr, the eyes were enucleated, under terminal anaesthesia (sodium pentobarbital, 120 mg/kg, im). Retinas were flat-mounted on acetate filter discs and superfused with oxygenated physiological saline solution (PSS) for 30min at 0.4mL/min. Five baseline fractions were collected (B1-B5), then three stimulated fractions were collected in the presence of PSS containing 50mM KCl (K1-K3) at 2min intervals. 3 H-acetylcholine ( 3 H-ACh) in each fraction was quantified by liquid scintillation counting. Significant amounts of myopia were induced in MD eyes after 2 (-5.1±0.8D) and 7 days (-18.8±2.4D) relative to control eyes (paired t-test p 3 H-ACh release was 146±15% above basal levels (K2/B1%) from retinas of normal animals. After 2 days MD, there was no significant difference between KCl-evoked release of 3 H-ACh from deprived eyes (147 39%) compared to control eyes (198±61%, paired t-test, p=0.27) or the eyes of normal animals (ANOVA, p>0.5). Similar results were obtained following 7 days MD. The results demonstrate that evoked acetylcholine release from the chick retina of myopic eyes is unaltered relative to control or normal eyes using an in vitro approach. Copyright (2002) Australian Neuroscience Society

Pivotal roles of Fezf2 in differentiation of cone OFF bipolar cells and functional maturation of cone ON bipolar cells in retina.

Science.gov (United States)

Suzuki-Kerr, Haruna; Iwagawa, Toshiro; Sagara, Hiroshi; Mizota, Atsushi; Suzuki, Yutaka; Watanabe, Sumiko

2018-06-01

During development of the retina, common retinal progenitor cells give rise to six classes of neurons that subsequently further diversify into more than 55 subtypes of neuronal subtypes. Here, we have investigated the expression and function of Fezf2, Fez zinc finger family of protein, in the developing mouse retina. Expression of Fezf2 transcripts was strongly observed in the embryonic retinal progenitors at E14.5 and declined quickly in subsequent development of retina. Then, in postnatal stage at around day 8, Fezf2 was transiently expressed then declined again. Loss-of-function analysis using retinas from mice in which Fezf2 coding region was substituted with β-galactosidase showed that Fezf2 is expressed in a subset of cone OFF bipolar cells and required for their differentiation. Using electroretinogram, we found that Fezf2 knockout retina exhibited significantly reduced photopic b-wave, suggesting functional abnormality of cone ON bipolar cells. Furthermore, reduced expression of synaptic protein Trpm1 and structural alteration of ON bipolar cell invagination, both of which affected cone photoreceptor terminal synaptic activity, was identified by transmission electron microscopy and immunohistochemistry, respectively. Taken together, our results show that Fezf2 is indispensable in differentiation of bipolar precursors into cone OFF bipolar cells and in functional maturation of cone ON bipolar cells during development of mouse retina. These results contribute to our understanding of how diversity of neuronal subtypes and hence specificity of neuronal connections are established in the retina by intrinsic cues. Copyright © 2018 Elsevier Ltd. All rights reserved.

Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration.

Science.gov (United States)

Yang, Fan; Ma, Hongwei; Belcher, Joshua; Butler, Michael R; Redmond, T Michael; Boye, Sanford L; Hauswirth, William W; Ding, Xi-Qin

2016-12-01

Recent studies have implicated thyroid hormone (TH) signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we found that antithyroid treatment preserves cones. This work investigates the significance of targeting intracellular TH components locally in the retina. The cellular TH level is mainly regulated by deiodinase iodothyronine (DIO)-2 and -3. DIO2 converts thyroxine (T4) to triiodothyronine (T3), which binds to the TH receptor, whereas DIO3 degrades T3 and T4. We examined cone survival after overexpression of DIO3 and inhibition of DIO2 and demonstrated the benefits of these manipulations. Subretinal delivery of AAV5-IRBP/GNAT2-DIO3, which directs expression of human DIO3 specifically in cones, increased cone density by 30-40% in a Rpe65 -/- mouse model of Lebers congenital amaurosis (LCA) and in a Cpfl1 mouse with Pde6c defect model of achromatopsia, compared with their respective untreated controls. Intravitreal and topical delivery of the DIO2 inhibitor iopanoic acid also significantly improved cone survival in the LCA model mice. Moreover, the expression levels of DIO2 and Slc16a2 were significantly higher in the diseased retinas, suggesting locally elevated TH signaling. We show that targeting DIOs protects cones, and intracellular inhibition of TH components locally in the retina may represent a novel strategy for retinal degeneration management.-Yang, F., Ma, H., Belcher, J., Butler, M. R., Redmond, T. M., Boye, S. L., Hauswirth, W. W., Ding, X.-Q. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration. © FASEB.

Adaptive optics imaging of the retina

Directory of Open Access Journals (Sweden)

Rajani Battu

2014-01-01

Full Text Available Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO and American Academy of Ophthalmology (AAO meetings. In total, 261 relevant publications and 389 conference abstracts were identified.

Análisis de viabilidad Técnica y Económica de un proyecto inmobiliario de Vivienda en el Sector Sur de la Ciudad de Quito

OpenAIRE

Garcia Cabrera, María Teresa

2012-01-01

A pesar de la crisis financiera mundial ocasionada en los últimos años, la construcción de Proyectos Inmobiliarios en el país y especialmente en la ciudad de Quito no se ha detenido, sigue existiendo un amplio mercado lo que permite gestionar proyectos de esta magnitud. El Proyecto Inmobiliario de Vivienda en el Sector Sur de la Ciudad de Quito, denominado Mirador Sur Quitumbe, es un proyecto de 16 viviendas unifamiliares distribuidas en dos bloques de 8 unidades habitacionales cada uno. E...

Circadian rhythms and light responsiveness of mammalian clock gene, Clock and BMAL1, transcripts in the rat retina.

Science.gov (United States)

Namihira, M; Honma, S; Abe, H; Tanahashi, Y; Ikeda, M; Honma, K

1999-08-13

Circadian expression and light-responsiveness of the mammalian clock genes, Clock and BMAL1, in the rat retina were examined by in situ hydbribization under constant darkness. A small but significant daily variation was detected in the Clock transcript level, but not in BMAL1. Light increased the Clock and BMAL1 expressions significantly when examined 60 min after exposure. The light-induced gene expression was phase-dependent for Clock and peaked at ZT2, while rather constant throughout the day for BMAL1. These findings suggest that Clock and BMAL1 play different roles in the generation of circadian rhytm in the retina from those in the suprachiasmatic nucleus. Different roles are also suggested between the two genes in the photic signal transduction in the retina.

“Análisis sociolingüístico en contexto de cotidianidad: un acercamiento a la investigación formativa"

Directory of Open Access Journals (Sweden)

JOSELYN CORREDOR TAPIAS

2006-01-01

Full Text Available El artículo pretende un acercamiento al lenguaje en un contexto social específico –unacafetería– con el fin de, a partir de actos de habla producidos por meseros, colegir elementosde análisis, fundamentados en algunos postulados teóricos sobre la sociolingüística y enciertos principios metodológicos que guiaron este intento de investigación formativa, respectode la recurrencia –o ausencia– de dichos actos. Es un trabajo de campo, sencillo –aunquejuicioso–. El artículo muestra, tanto un corpus lexical de actos de habla compilados meseros(en las ciudades de Tunja y de Sogamoso, como el análisis estadístico –muy básico– einterpretativo de los mismos. El estudio, en general, se centra en la relación lenguaje-contexto sociocultural.

X-ray microprobe analysis of the retina and RPE in sheep with ovine ceroid-lipofuscinosis

International Nuclear Information System (INIS)

Samuelson, D.A.; Armstrong, D.; Jolly, R.

1990-01-01

Ovine ceroid-lipofuscinosis (OCL) is one animal model for the human condition, and because autofluorescent lipopigments are prominent in the brain and eye, it may also prove useful as a model for aging. For example, a progressive decline in electrical recording from brain and retina are observed in both aging and OCL. Samples of retinal and retinal pigment epithelial (RPE) tissues were obtained from a young control. 2 animals with OCL and a normal aged sheep. Specimens were cryo-fractured and examined by scanning electron microscopy/x-ray microanalysis. Measurements made of 6 individual cells in the ganglion layer of OCL specimens, the remainder of the retina, and RPE showed age-related changes in zinc, iron, and copper which were associated with lipopigment accumulation in the RPE. There was marked decrease in phosphate, sulfur, and manganese levels, as photoreceptor cells and their outer segments are lost in the disease process. This is the first report of metal analysis in the retina and RPE in a disease entity, and as a function of normal aging

Electroretinography: A biopotential to assess the function/dysfunction of the retina

Science.gov (United States)

Quintana, Quinteros; Benedetto, M. L.; Maldonado, M. M.; de Payer E., A. C. Vera; Contin, M. A.

2016-04-01

The Electroretinography (ERG) is a noninvasive technique that allows the assessment of functional integrity of the retina. The ERG recordings are biopotencials acquired in the corneal surface as a response of retinal tissue against controlled light stimuli. In clinical ophthalmology ERG is not commonly used but nowadays, because of the high incidence of degenerative diseases of the retina (RD), its use should be increased. Like other biopotentials as electrocardiography (ECG), electroencephalogram (EEG) and electromyography (EMG), ERG is a low amplitude signal, in this case a few hundred of microvolts (µV), which must be fitted and processed. The ERG signals are affected in morphology in the presence of pathologies that affects the integrity of the different retinal cell groups, for example due to some RD. In advanced cases of RD recordings can be abolished in the time domain; and yet in them it is believed that there is relevant clinical information making the ERG a great potential diagnostic tool.

Lactate Transport and Receptor Actions in Retina

DEFF Research Database (Denmark)

Kolko, Miriam; Vosborg, Fia; Henriksen, Jens Ulrik Lütken

2016-01-01

known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions......In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also...

Proyecto de abastecimiento y saneamiento en Villafáfila (Zamora)

OpenAIRE

Segurado Vicente, Javier

2012-01-01

[ES] Documentación para definir y valorar las obras necesarias para la construcción de las redes de abastecimiento y saneamiento de Villafáfila. [EN] Documentation to define and assess the work required to build networks Villafáfila supply and sanitation. Proyecto Fin de Carrera-Universidad de Salamanca, Escuela Politécnica Superior de Zamora, 2012

Sistema web para la gestión de proyectos y el control interno de una empresa

OpenAIRE

Espinosa Martín, Francisco Javier

2011-01-01

[ES] El proyecto tiene su campo de aplicación en la generación de una aplicación web para la gestión de la empresa. El lenguaje de desarrollo PHP con HTML y el servidor web de uso local Appserv. [EN] The project has its field of application in the generation of a web application for managing the company. The PHP development language with HTML and web server for local use Appserv. Proyecto fin de carrera-Universidad de Salamanca, Escuela Politécnica Superior de Zamora, 2011

Proyecto de creación de un restaurante de comida light en la ciudad de Cuenca

OpenAIRE

Avila Guambaña, Mónica Bernardita; Quizhpe Flores, Rosa Isabel

2006-01-01

La presente tesina se desarrolló en vista de que en la ciudad donde se va a llevar a cabo dicho proyecto no existen varias alternativas que brinde este tipo de servicio, por lo tanto la población requiere de un lugar en donde puedan disfrutar alimentándose sana y nutritivamente. Y por ende puedan mantener una salud y el bienestar total. El primer capítulo corresponde al área administrativa, en un primer plano enfocando conceptos sobre los cuales se basará nuestro proyecto como: la nutrición y...

A Retina-Like Dual Band Organic Photosensor Array for Filter-Free Near-Infrared-to-Memory Operations.

Science.gov (United States)

Wang, Hanlin; Liu, Hongtao; Zhao, Qiang; Ni, Zhenjie; Zou, Ye; Yang, Jie; Wang, Lifeng; Sun, Yanqiu; Guo, Yunlong; Hu, Wenping; Liu, Yunqi

2017-08-01

Human eyes use retina photoreceptor cells to absorb and distinguish photons from different wavelengths to construct an image. Mimicry of such a process and extension of its spectral response into the near-infrared (NIR) is indispensable for night surveillance, retinal prosthetics, and medical imaging applications. Currently, NIR organic photosensors demand optical filters to reduce visible interference, thus making filter-free and anti-visible NIR imaging a challenging task. To solve this limitation, a filter-free and conformal, retina-inspired NIR organic photosensor is presented. Featuring an integration of photosensing and floating-gate memory modules, the device possesses an acute color distinguishing capability. In general, the retina-like photosensor transduces NIR (850 nm) into nonvolatile memory and acts as a dynamic photoswitch under green light (550 nm). In doing this, a filter-free but color-distinguishing photosensor is demonstrated that selectively converts NIR optical signals into nonvolatile memory. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proyectos alternativos y diversas opiniones sobre la modificación del ejercicio de la docencia de la Educación Superior

Directory of Open Access Journals (Sweden)

Autores Varios

2012-11-01

Full Text Available Proyecto originalPresentación alternativaOpinión CIN sobre el proyecto de leyOpinión CRUP en la Comisión de Educación HCDNOpinion ADEEPRA y CAIEP en la Comisión de Educación HCDN

Estado de la gerencia de proyectos en PYMES del sector artes gráficas y propuestas de lineamientos para su mejoramiento

Directory of Open Access Journals (Sweden)

Óscar Rubiano Ovalle

2012-06-01

Full Text Available El propósito de este artículo es presentar los resultados de una investigación mediante la cual se diagnosticó el estado de la gerencia de proyectos en un grupo de empresas del sector artes gráficas de la ciudad de Cali. En una población conformada por 30 empresas catalogadas como MIPYME, de acuerdo con la Ley 905 del 2004, se aplicó un instrumento basado en los modelos de madurez de gerencia de proyectos más referenciados, como el Organizational Project Management Maturity Model (OPM3 y el Programme and Project Management Maturity Model (P3M3. El instrumento, respondido en entrevistas personales por gerentes y jefes de producción, permitió detectar que en términos generales existe un bajo nivel de la gerencia de proyectos que permita identificar, evaluar y ejecutar proyectos exitosamente y que a su vez generen un impacto estratégico para las organizaciones. En vista de los resultados, en este artículo se expone un marco de lineamientos que propicie la adherencia de las pequeñas y medianas empresas a una metodología de proyectos aliado a una gestión estratégica.

Evaluación económica de proyectos de inversión basada en la teoría de opciones reales

Directory of Open Access Journals (Sweden)

Ignacio Andres Garrido Concha

2003-07-01

Full Text Available En la presente investigación se analiza un nuevo enfoque, basado en la aplicación de la Teoría de Opciones Reales para realizar la evaluación económica de proyectos de inversión. El mismo, posee el potencial de entregar una aproximación del valor de la flexibilidad que posee un proyecto, permitiendo al evaluador capturar numéricamente el valor de la estrategia. El objetivo fundamental de la presente investigación fue proponer una “Metodología de Evaluación Económica de proyectos de inversión a partir de la Teoría de Opciones Reales”, con el fin de presentarla como una herramienta de evaluación alternativa a los métodos tradicionales. A modo de aplicación de esta metodología, basada en el Método Binomial con Transformada Logarítmica, se realizó la evaluación económica de distintos proyectos reales los cuales corresponden a distintas variaciones del proyecto “Implementación de un Sistema de Información Geográfica (SIG para controlar la cartografía de las plantaciones pertenecientes a Forestal Mininco S.A” estudiadas previamente por Julio Becker.  

Common Variants in the COL4A4 Gene Confer Susceptibility to Lattice Degeneration of the Retina

OpenAIRE

Meguro, Akira; Ideta, Hidenao; Ota, Masao; Ito, Norihiko; Ideta, Ryuichi; Yonemoto, Junichi; Takeuchi, Masaki; Uemoto, Riyo; Nishide, Tadayuki; Iijima, Yasuhito; Kawagoe, Tatsukata; Okada, Eiichi; Shiota, Tomoko; Hagihara, Yuta; Oka, Akira

2012-01-01

Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion predisposing the patient to retinal tears and detachment. The etiology of this degeneration is still uncertain, but it is likely that both genetic and environmental factors play important roles in its development. To identify genetic susceptibility regions for lattice degeneration of the retina, we performed a genome-wide association study (GWAS) using a dense panel of 23,465 microsatellite...

Immunohistochemical Localization of an Isoform of TRK-Fused Gene-Like Protein in the Rat Retina

International Nuclear Information System (INIS)

Masuda, Chiaki; Takeuchi, Shigeko; Bisem, Naomi J.; Vincent, Steven R.; Tooyama, Ikuo

2014-01-01

The TRK-fused gene (TFG) was originally identified in chromosome translocation events, creating a pair of oncogenes in some cancers, and was recently demonstrated as the causal gene of hereditary motor and sensory neuropathy with proximal dominant involvement. Recently, we cloned an alternative splicing variant of Tfg from a cDNA library of the rat retina, tentatively naming it retinal Tfg (rTfg). Although the common form of Tfg is ubiquitously expressed in most rat tissues, rTfg expression is localized to the central nervous system. In this study, we produced an antibody against an rTFG-specific amino acid sequence and used it to examine the localization of rTFG-like protein in the rat retina by immunohistochemistry and Western blots. Western blot analysis showed that the antibody detected a single band of 24 kDa in the rat retina. When we examined rTFG recombinant protein, the antibody detected two bands of about 42 kDa and 24 kDa. The results suggest that the 24 kDa rTFG-like protein is a fragment of rTFG. In our immunohistochemical studies of the rat retina, rTFG-like immunoreactivity was observed in all calbindin D-28K-positive horizontal cells and in some syntaxin 1-positive amacrine cells (ACs). In addition, the rTFG-like immunopositive ACs were actually glycine transporter 1-positive glycinergic or glutamate decarboxylase-positive GABAergic ACs. Our findings indicate that this novel 24 kDa rTFG-like protein may play a specific role in retinal inhibitory interneurons

Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides

KAUST Repository

Busserolles, Fanny de

2017-11-09

Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light conditions; hence, most species have lost their cones in favor of a simplex retina composed exclusively of rods. Although the pearlsides, Maurolicus spp., have such a pure rod retina, their behavior is at odds with this simplex visual system. Contrary to other deep-sea fishes, pearlsides are mostly active during dusk and dawn close to the surface, where light levels are intermediate (twilight or mesopic) and require the use of both rod and cone photoreceptors. This study elucidates this paradox by demonstrating that the pearlside retina does not have rod photoreceptors only; instead, it is composed almost exclusively of transmuted cone photoreceptors. These transmuted cells combine the morphological characteristics of a rod photoreceptor with a cone opsin and a cone phototransduction cascade to form a unique photoreceptor type, a rod-like cone, specifically tuned to the light conditions of the pearlsides\\' habitat (blue-shifted light at mesopic intensities). Combining properties of both rods and cones into a single cell type, instead of using two photoreceptor types that do not function at their full potential under mesopic conditions, is likely to be the most efficient and economical solution to optimize visual performance. These results challenge the standing paradigm of the function and evolution of the vertebrate duplex retina and emphasize the need for a more comprehensive evaluation of visual systems in general.

"Para derribar todas las fronteras": un proyecto realizado con inmigrantes latinoamericanos

OpenAIRE

Lic. Laura Guillermina Moyano Ortiz

1998-01-01

Quería comentarles que este proyecto que comparto hoy con ustedes surge de una idea inicial gestada en el seno de una organización sin fines de lucro, de inspiración cristiana que, creo, algunos de ustedes conocerán probablemente de nombre: Cáritas Arquidiocesana de Córdoba, Argentina.

Simultaneous in vivo imaging of melanin and lipofuscin in the retina with multimodal photoacoustic ophthalmoscopy

Science.gov (United States)

Zhang, Xiangyang; Zhang, Hao F.; Zhou, Lixiang; Jiao, Shuliang

2012-02-01

We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective vs. exacerbate) in the RPE in the aging process. We successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

ALGUNAS HERRAMIENTAS PARA LA TOMA DE DECISIONES DE INVERSIÓN EN PROYECTOS DE ALTO RIESGO

Directory of Open Access Journals (Sweden)

Julio Villarreal

2007-01-01

Full Text Available En este trabajo se presenta un posible aplicación metodológica para la toma de decisiones de inversión en proyectos de alto riesgo como las que típicamente son apoyados por los llamados fondos de capital de riesgo. El objetivo final es mostrar como es posible a través de esta metodología, reducir las asimetrías de información típicas en la relación entre inversionistas de riesgo (accionistas de capital y gestores de proyectos (accionistas industriales. La metodología propuesta se aplica a un plan de negocios real, pero de igual manera se puede aplicar a otros proyectos riesgosos, y muestra cómo una adecuada estructuración de un proceso de decisión, usando los modelos y herramientas adecuadas puede ser muy útil tanto en decisiones de fondos de inversión como en la estructuración de procesos de evaluación de alternativas de decisión estratégicas en las que el riesgo hace inapropiado el tradicional análisis determinístico.

Three dimensional reconstruction of tomographic images of the retina

International Nuclear Information System (INIS)

Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

2007-01-01

The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

Inner neural retina loss in central retinal artery occlusion.

Science.gov (United States)

Ikeda, Fumiko; Kishi, Shoji

2010-09-01

To report morphologic retinal changes and visual outcomes in acute and chronic central retinal artery occlusion (CRAO). We reviewed ten eyes of ten patients with CRAO (age, 65.3 ± 10.2 years) and measured retinal thicknesses at the central fovea and the perifovea using optical coherence tomography (OCT) over 8 ± 4 months. During the acute phase (within 10 days), the mean inner retinal thicknesses were 148% and 139% of normal values at 1 mm nasal and temporal to the fovea. They decreased to 22% and 11% of normal inner retinal thickness during the chronic phase (3 months or later). The retinal thickness at the perifovea decreased linearly until 3 months but was stable during the chronic phase. In contrast, the foveal thickness increased slightly in the acute phase but was equivalent to the normal level during the chronic phase. As a result of inner retinal atrophy, the foveal pit was shallow during the chronic phase. The final visual acuity was correlated positively with retinal thickness at the perifovea during the chronic CRAO phase. OCT showed that inner retinal necrosis with early swelling and late atrophy occurred in CRAO. The fovea and outer retina appeared to be excluded from ischemic change. The residual inner retina at the perifovea determined the final visual outcomes.

Mirar y proyectar: Proyectos 1, Curso 2015-2016

OpenAIRE

Moreno Moreno, María Purificación; Ródenas López, Manuel Alejandro

2016-01-01

Mirar y Proyectar, es un recopilatorio de los trabajos más destacados de los alumnos del Primer Curso de Grado de Fundamentos de Arquitectura en la asignatura de Proyectos 1, desarrollada durante el segundo cuatrimestre del curso 2015-2016. Los ejercicios expuestos, con sus enunciados previos, tratan de responder al objetivo general de acercar al alumno al hecho arquitectónico desde su génesis: de lo más general a lo más particular. Mirar con ojos de arquitecto requiere de un pensamiento abst...

Subthreshold transpupillary thermotherapy reduces experimental choroidal neovascularization in the mouse without collateral damage to the neural retina.

Science.gov (United States)

Ming, Yue; Algvere, Peep V; Odergren, Anne; Berglin, Lennart; van der Ploeg, Ingeborg; Seregard, Stefan; Kvanta, Anders

2004-06-01

Transpupillary thermotherapy (TTT) is currently being evaluated for treatment of choroidal neovascularization (CNV) in age-related macular degeneration. To optimize TTT for CNV, the effect was analyzed of invisible (subthreshold) or visible (threshold) doses of TTT on the normal mouse retina and on experimental CNV. TTT was delivered to the normal retina of 42 mice with a diode laser at increasing power settings (50, 60, 70, or 80 mW), to obtain thermal lesions ranging from invisible (subthreshold) to visible (threshold) burns. CNV was induced in 53 mice by krypton laser photocoagulation of the fundus, after which the CNV lesions were treated with TTT (50, 60, or 80 mW). Eyes were enucleated 7 days after TTT and prepared for histology, and the CNV complex was evaluated on hematoxylin-eosin stained serial sections by measuring the maximum height of the CNV lesions. Ultrastructural changes were examined by transmission electron microscopy. Increasing the TTT laser power yielded gradually more visible effects. At 50 mW, which induced subthreshold burns, no damage was seen in the neural retina, retinal pigment epithelium (RPE), or choroid at any time point. By contrast, eyes treated with higher power exhibited progressively more damage to the neural retina, including a complete disruption of the outer nuclear layer. When TTT was applied to the laser-induced CNV lesions, the height of lesions was significantly reduced (P response to all three power settings at 7 days after treatment. The mean relative thickness of the CNV lesion was 3.29 +/- 0.89 in untreated mice, whereas in TTT-treated mice it was 1.69 +/- 0.35, 1.69 +/- 0.41 and 1.70 +/- 0.17 at power settings of 50, 60, and 80 mW, respectively. The overlying neural retina showed no apparent damage with the 50- or 60-mW settings, whereas outer nuclear layer disruption occurred with a power of 80 mW. Electron microscopy confirmed the presence of vascular occlusion at 1 day and a fibrotic scar at 7 days after TTT

Desarrollo de proyecto progresivo de vivienda de interés social con sistemas tradicionales e industrializados

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Gafaro Briceño, Jorge

1984-06-01

Full Text Available On taking up the development of an architectural project for mass housing, «Proyectos y Construcciones G.E.G. considers that, in the present state of development of the building industry in Colombia and its financial situation, the most convenient thing to do would be to continue using traditional materials and systems, to which would be applied those pertaining to research, planning and organization which are characteristic of any industry enjoying high output, but which are considered by us to be foreign to traditional construction.Al afrontar el desarrollo de un proyecto arquitectónico para vivienda masiva, Proyectos y Construcciones G.E.G. considera que en el estado actual de desarrollo de la industria de la construcción en Colombia y su situación económica, lo más conveniente es continuar usando materiales y sistemas tradicionales, aplicándoles los de estudios, planeación y organización que son propios de cualquier industria de alta productividad, pero que entre nosotros se consideran ajenos a la construcción tradicional.

Proyecto María María

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Prieto Peña, Ana María

2014-01-01

María María es un proyecto que se desarrollara en sector de la Joyería y la Bisutería pero con un fuerte enfoque Cultural y artístico. Nuestro producto es más que un accesorio, por un lado es la belleza y distinción que buscan las mujeres y por otro lado es la experiencia del cliente, quien tendrá la oportunidad de personalizar su accesorio, ser diseñador por un rato y lucir su propia creación. Este accesorio pone en contacto al usuario con el mundo literario; es decir con pequeños universo...

Automatic and manual segmentation of healthy retinas using high-definition optical coherence tomography.

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Golbaz, Isabelle; Ahlers, Christian; Goesseringer, Nina; Stock, Geraldine; Geitzenauer, Wolfgang; Prünte, Christian; Schmidt-Erfurth, Ursula Margarethe

2011-03-01

This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 μm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

Comparative immunolocalization of the plasma membrane calcium pump and calbindin D28K in chicken retina during embryonic development

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N. Tolosa de Talamoni

2010-05-01

Full Text Available The immunolocalization of the plasma membrane calcium pump (PMCA was studied in 4-week-old chick retina in comparison with calbindin D28K (CaBP immunostaining. We have demonstrated that the monoclonal anti-PMCA antibody 5F10 from human erythrocyte plasma membrane crossreacts with a Ca2+ pump epitope of the cells from the neural retina. The immunolocalization of both proteins was also studied during the embryonic development of the chicken retina. At age 4.5 days, the cells of the retina were faintly immunoreactive to PMCA and CaBP antibodies, but the lack of cellular aggregation and differentiation did not allow discrimination between the two proteins. A clear difference in the localization was seen from the tenth day of development through post-hatching with slight variation. PMCA localized mainly in the outer and inner plexiform layers, in some cells in the ganglion layer, in the nerve fiber layer and slightly in the photoreceptor cells. CaBP was intensely stained in cones, cone pedicles and some amacrine cells. The number of CaBP positive amacrine cells declined after hatching. A few ganglion cells and several nerve fibers were CaBP 333 immunoreactive. The role of these proteins in the early stages of retinal development is unknown, but the results suggest that Ca2+ homeostasis in the retina is well regulated, probably to avoid excessive accumulation of Ca2+, which often leads to neurodegeneration.

Creación de base de datos para proyectos multisite de eficiencia energética en el sector de las telecomunicaciones

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Izquierdo Balaciart, Berta

2017-01-01

En este trabajo se pretende crear una base de datos para una ingeniería de eficiencia energética para proyectos en el sector de las telecomunicaciones para optimizar el tratamiento de datos y reducir el tiempo dedicado a ello en cada una de las fases del proyecto.

Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study.

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Christiansen, Anders Tolstrup; Kiilgaard, Jens Folke; Klemp, Kristian; Woldbye, David Paul Drucker; Hannibal, Jens

2018-04-17

Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy and 3D reconstructions, we found NPY to be expressed in GABAergic and calretinin-immunoreactive (-ir) amacrine cells of both species as well as parvalbumin-ir amacrine cells of humans. Furthermore, we identified at least two different types of medium- to wide-field NPY-ir amacrine cells. Finally, we detected likely synaptic appositions between the NPY-ir amacrine cells and melanopsin- and nonmelanopsin-ir ganglion cells, GABAergic and dopaminergic amacrine cells, rod bipolar cells, and horizontal cells, suggesting that NPY-ir cells play diverse roles in modulation of both image and non-image forming retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY signaling in retinal function. © 2018 Wiley Periodicals, Inc.

Municipios por la salud: Proyecto provincial de Ciudad de la Habana

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Ana María Chalgub Moreno

1999-01-01

Full Text Available Los conceptos de Promoción de Salud no son nuevos para los que enfocan la salud como parte de una totalidad y no como un componente aislado, es "proporcionar a los pueblos los medios necesarios para mejorar la salud y ejercer un mayor control sobre ella". Los proyectos de Municipios por la Salud, integran la acción de Promoción y Prevención, pilares fundamentales en el modelo de Atención Primaria en Cuba para el desarrollo de salud ambiental, enfermedades no trasmisibles, trasmisibles y otros daños de la salud. En los municipios donde el gobierno solicita la implantación de estos proyectos, realizará la capacitación en Promoción de Salud a los miembros del Consejo de Administración Municipal, Consejos de Salud Municipales y Populares, personal implicado en el proyecto y a los promotores de la población que se han involucrado en el movimiento; se realizará el análisis de la Situación de Salud con participación comunitaria y determinación de prioridades, utilizando el Método de Hanlon, se caracterizará por todos los organismos, incluyendo salud, el lugar donde se va a trabajar; se confeccionará el proyecto y los subproyectos que saldrán a partir del análisis con la comunidad, se realizará evaluación inicial por medio de encuestas o grupos focales, realizándose monitoreo sistemático para evaluar su marcha. El impacto de estos proyectos se medirá a corto, mediano y largo plazo.The conepts of health promotion are not new for those who consider health as a whole and not as an isolated component. It means to -give peoples the necessary means to improve health and to have a better control of its-. The projects of the municipalites for health are part of the action of Promotion and Prevention, which are the fundamental milestones in the model of Primary Care in Cuba for the development of environmental health, communicable and non- communicable diseases and other health damages. In the municipalities where the goverment thinks

Espacio Comunitario para Lebu (Proyecto de título

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Iván Cartes Siade

1985-12-01

Full Text Available El proyecto Modelo de Espacio Comunitario para una ciudad de Fundación Española, con borde de ribera, aplicado en la ciudad de Lebu, VIII Región, se generó a partir del concurso para estudiantes en el marco de celebración del Bicentenario de la Escuela de Pintura, Escultura y Arquitectura de México y con motivo de la IX Conferencia Latinoamericana de Escuelas y Facultades de Arquitectura (IX CLEFA.

Complex computation in the retina

Science.gov (United States)

Deshmukh, Nikhil Rajiv

Elucidating the general principles of computation in neural circuits is a difficult problem requiring both a tractable model circuit as well as sophisticated measurement tools. This thesis advances our understanding of complex computation in the salamander retina and its underlying circuitry and furthers the development of advanced tools to enable detailed study of neural circuits. The retina provides an ideal model system for neural circuits in general because it is capable of producing complex representations of the visual scene, and both its inputs and outputs are accessible to the experimenter. Chapter 2 describes the biophysical mechanisms that give rise to the omitted stimulus response in retinal ganglion cells described in Schwartz et al., (2007) and Schwartz and Berry, (2008). The extra response to omitted flashes is generated at the input to bipolar cells, and is separable from the characteristic latency shift of the OSR apparent in ganglion cells, which must occur downstream in the circuit. Chapter 3 characterizes the nonlinearities at the first synapse of the ON pathway in response to high contrast flashes and develops a phenomenological model that captures the effect of synaptic activation and intracellular signaling dynamics on flash responses. This work is the first attempt to model the dynamics of the poorly characterized mGluR6 transduction cascade unique to ON bipolar cells, and explains the second lobe of the biphasic flash response. Complementary to the study of neural circuits, recent advances in wafer-scale photolithography have made possible new devices to measure the electrical and mechanical properties of neurons. Chapter 4 reports a novel piezoelectric sensor that facilitates the simultaneous measurement of electrical and mechanical signals in neural tissue. This technology could reveal the relationship between the electrical activity of neurons and their local mechanical environment, which is critical to the study of mechanoreceptors

ACERCAMIENTO AL PROCESO DE SOCIALIZACIÓN DE LA POBLACIÓN INFANTIL CABÉCAR DE CHIRRIPÓ

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Hannia Watson Soto

2015-01-01

Full Text Available Este artículo es producto de la investigación “Acercamiento al proceso de s ocialización de la población infantil cabécar de Chirripó”, que se desarrolló desde el Instituto de Investigación en Educación (INIE. La Universidad de Costa Rica como institución pública de educación superior, ha venido asumiendo la responsabilidad de co ntribuir a través de sus diferentes ámbitos de trabajo, en la resolución de necesidades de la comunidad nacional para la búsqueda de mejores condiciones de vida de todas las personas que la habitan, es así como en los últimos años ha generado reflexiones s obre la urgencia de generar procesos educativos con pertinencia cultural en las comunidades cabécares de Chirripó, este trabajo pretende aportar en este sentido. Para ello se recurre al estudio de los procesos de socialización de este grupo étnico para ide ntificar las prácticas de crianza propias que les permiten construir y resignificar su identidad cultural, las cuales se concluye deben ser consideradas en la educación inicial formal para generar procesos educativos pertinentes y significativos.

Molecular Characterization of Notch1 Positive Progenitor Cells in the Developing Retina.

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Galina Dvoriantchikova

Full Text Available The oscillatory expression of Notch signaling in neural progenitors suggests that both repressors and activators of neural fate specification are expressed in the same progenitors. Since Notch1 regulates photoreceptor differentiation and contributes (together with Notch3 to ganglion cell fate specification, we hypothesized that genes encoding photoreceptor and ganglion cell fate activators would be highly expressed in Notch1 receptor-bearing (Notch1+ progenitors, directing these cells to differentiate into photoreceptors or into ganglion cells when Notch1 activity is diminished. To identify these genes, we used microarray analysis to study expression profiles of whole retinas and isolated from them Notch1+ cells at embryonic day 14 (E14 and postnatal day 0 (P0. To isolate Notch1+ cells, we utilized immunomagnetic cell separation. We also used Notch3 knockout (Notch3KO animals to evaluate the contribution of Notch3 signaling in ganglion cell differentiation. Hierarchical clustering of 6,301 differentially expressed genes showed that Notch1+ cells grouped near the same developmental stage retina cluster. At E14, we found higher expression of repressors (Notch1, Hes5 and activators (Dll3, Atoh7, Otx2 of neuronal differentiation in Notch1+ cells compared to whole retinal cell populations. At P0, Notch1, Hes5, and Dll1 expression was significantly higher in Notch1+ cells than in whole retinas. Otx2 expression was more than thirty times higher than Atoh7 expression in Notch1+ cells at P0. We also observed that retinas of wild type animals had only 14% (P < 0.05 more ganglion cells compared to Notch3KO mice. Since this number is relatively small and Notch1 has been shown to contribute to ganglion cell fate specification, we suggested that Notch1 signaling may play a more significant role in RGC development than the Notch3 signaling cascade. Finally, our findings suggest that Notch1+ progenitors--since they heavily express both pro-ganglion cell (Atoh7

Effect of chronic administration of sildenafil citrate (Viagra) on the histology of the retina and optic nerve of adult male rat.

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Eltony, Sohair A; Abdelhameed, Sally Y

2017-04-01

Abnormal vision has been reported by 3% of patients treated with sildenafil citrate (Viagra). Although many men use Viagra for an extended period for treatment of erectile dysfunction, the implications of the long term-daily use of it on the retina and optic nerve are unclear. To investigate the effect of chronic daily use of sildenafil citrate in a dose equivalent to men preferred therapeutic dose on the histology of the retina and optic nerve of adult male rat. Eighteen adult male Wistar rats were equally divided into three groups. Group I: control. Group II: treated with sildenafil citrate orally (10mg/kg/day) for 8 weeks. Group III (withdrawal): treated as group II and then left for 4 weeks without treatment. Specimens from the retina and optic nerve were processed for light and electron microscopy. In sildenafil citrate treated group, the retina and optic nerve revealed vacuolations and congested blood capillaries with apoptotic endothelial and pericytic cells, and thickened basal lamina. Caspase-3 (apoptotic marker) and CD31 (endothelial marker) expression increased. Glial cells revealed morphological changes: Müller cells lost their processes, activated microglia, astrocytic clasmatodendrosis, degenerated oligodendrocytes surrounded by disintegrated myelin sheathes of the optic nerve fibers. The retina and optic nerve of the withdrawal group revealed less vacuolations and congestion, and partial recovery of the glial cells. Chronic treatment with sildenafil citrate (Viagra) caused toxic effect on the structure of the retina and optic nerve of the rat. Partial recovery was observed after drug withdrawal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pathological alterations typical of human Tay-Sachs disease, in the retina of a deep-sea fish

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Fishelson, L.; Delarea, Yacov; Galil, Bella S.

Micrographs of retinas from the deep-sea fish Cataetyx laticeps revealed visual cells containing membranous whorls in the ellipsoids of the inner segments resulting from stretching and modifications of the mitochondria membranes and their cristae. These pathological structures seem to be homologous to the whorls observed in retinas of human carriers of Tay-Sachs disease. This disease, a genetic disorder, is found in humans and some mammals. Our findings in fish suggest that the gene responsible can be found throughout the vertebrate evolutionary tree, possibly dormant in most taxa.

Descubrimiento de conocimiento en lecciones aprendidas documentadas en los procesos de cierre de proyectos informáticos

OpenAIRE

Eliana Bárbara Ril Valentín; Rafael Rodríguez Puente; Pedro Y. Piñero Pérez; Hugo A. Martínez Noriegas

2013-01-01

La documentación de lecciones aprendidas permite visualizar los errores del pasado y mejorar el trabajo futuro. Aprender de la experiencia de proyectos anteriores contribuye a disminuir los riesgos, evitar problemas ya identificados y reutilizar las buenas prácticas para reducir el número de proyectos no exitosos. El objetivo de esta investigación es descubrir conocimiento a partir de la aplicación de árboles de decisión y tablas de contingencia en lecciones aprendidas documentadas en los pro...

Two classes of astrocytes in the adult human and pig retina in terms of their expression of high affinity NGF receptor (TrkA).

Science.gov (United States)

Ruiz-Ederra, Javier; Hitchcock, Peter F; Vecino, Elena

2003-02-13

Astrocytes have been implicated in axon guidance and synaptic regeneration in the retina and these processes involve activation of the high affinity nerve growth factor receptor, known as the tyrosine kinase A (TrkA) receptor. The purpose of the present study was to characterize the expression of TrkA in astrocytes of the adult pig and human retina. To this end, sections of human and pig retinas were immunolabeled with a combination of antibodies to glial fibrillary acidic protein (GFAP) and TrkA. Our study revealed that most of the GFAP-positive cells express TrkA, whereas a rare, novel subpopulation of astrocytes was found to be devoid of TrkA. Our results support the idea that astrocytes play an important neurotrophic role in the retina.

An artificial retina processor for track reconstruction at the LHC crossing rate

Science.gov (United States)

Bedeschi, F.; Cenci, R.; Marino, P.; Morello, M. J.; Ninci, D.; Piucci, A.; Punzi, G.; Ristori, L.; Spinella, F.; Stracka, S.; Tonelli, D.; Walsh, J.

2017-10-01

The goal of the INFN-RETINA R&D project is to develop and implement a computational methodology that allows to reconstruct events with a large number (> 100) of charged-particle tracks in pixel and silicon strip detectors at 40 MHz, thus matching the requirements for processing LHC events at the full bunch-crossing frequency. Our approach relies on a parallel pattern-recognition algorithm, dubbed artificial retina, inspired by the early stages of image processing by the brain. In order to demonstrate that a track-processing system based on this algorithm is feasible, we built a sizable prototype of a tracking processor tuned to 3 000 patterns, based on already existing readout boards equipped with Altera Stratix III FPGAs. The detailed geometry and charged-particle activity of a large tracking detector currently in operation are used to assess its performances. We report on the test results with such a prototype.

Sonic hedgehog promotes stem-cell potential of Mueller glia in the mammalian retina

International Nuclear Information System (INIS)

Wan Jin; Zheng Hua; Xiao Honglei; She Zhenjue; Zhou Guomin

2007-01-01

Mueller glia have been demonstrated to display stem-cell properties after retinal damage. Here, we report this potential can be regulated by Sonic hedgehog (Shh) signaling. Shh can stimulate proliferation of Mueller glia through its receptor and target gene expressed on them, furthermore, Shh-treated Mueller glia are induced to dedifferentiate by expressing progenitor-specific markers, and then adopt cell fate of rod photoreceptor. Inhibition of signaling by cyclopamine inhibits proliferation and dedifferentiation. Intraocular injection of Shh promotes Mueller glia activation in the photoreceptor-damaged retina, Shh also enhances neurogenic potential by producing more rhodopsin-positive photoreceptors from Mueller glia-derived cells. Together, these results provide evidences that Mueller glia act as potential stem cells in mammalian retina, Shh may have therapeutic effects on these cells for promoting the regeneration of retinal neurons

Sonic hedgehog promotes stem-cell potential of Mueller glia in the mammalian retina

Energy Technology Data Exchange (ETDEWEB)

Jin, Wan; Hua, Zheng; Honglei, Xiao; Zhenjue, She [Department of Anatomy, Histology and Embryology, Shanghai Medical School, Fudan University, 200032 Shanghai (China); Zhou Guomin [Department of Anatomy, Histology and Embryology, Shanghai Medical School, Fudan University, 200032 Shanghai (China)], E-mail: gmzhou185@yahoo.com.cn

2007-11-16

Mueller glia have been demonstrated to display stem-cell properties after retinal damage. Here, we report this potential can be regulated by Sonic hedgehog (Shh) signaling. Shh can stimulate proliferation of Mueller glia through its receptor and target gene expressed on them, furthermore, Shh-treated Mueller glia are induced to dedifferentiate by expressing progenitor-specific markers, and then adopt cell fate of rod photoreceptor. Inhibition of signaling by cyclopamine inhibits proliferation and dedifferentiation. Intraocular injection of Shh promotes Mueller glia activation in the photoreceptor-damaged retina, Shh also enhances neurogenic potential by producing more rhodopsin-positive photoreceptors from Mueller glia-derived cells. Together, these results provide evidences that Mueller glia act as potential stem cells in mammalian retina, Shh may have therapeutic effects on these cells for promoting the regeneration of retinal neurons.

Casas estudio: alternativa pedagógica para el proyecto de fin de carrera

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Edison Henao Carvajal

2011-12-01

Full Text Available Este artículo da cuenta del proceso de elaboración del trabajo de grado de algunos de los estudiantes inscritos en la Línea de Profundización en Proyectos Arquitectónicos, del programa curricular de Arquitectura, de la sede Manizales de la Universidad Nacional de Colombia, durante los semestres segundo del 2009 y primero del 2010. El propósito de la experiencia, coordinada por los autores del artículo, consistió en poner a prueba un método de enseñanza-aprendizaje para el taller de proyectos de fin de carrera, en el marco de una concepción pedagógica basada en la solución de problemas de forma, a partir del reconocimiento y de la asimilación de las soluciones universales presentes en las obras de los grandes maestros de la arquitectura. En contravía de la metodología de concepción arquitectónica contemporánea, basada en “la realización de las ideas del autor”, el taller se centró en recuperar las maneras de operar de la modernidad arquitectónica, en las que tiene mayor importancia la búsqueda de una implantación correcta de la obra, la solución de los requerimientos programáticos del proyecto, su concepción constructiva y el planteamiento consistente de los espacios requeridos, en este caso, para una casa-estudio.

Interventoría ambiental en proyectos de perforación de pozos petroleros

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Hugo Ibsen Zambrano Solarte

2003-01-01

Full Text Available El control sobre el cumplimiento de las normas legales ambientales vigentes, requiere la creación de herramientas o mecanismos tendientes a la preservación y conservación del medio natural y a la protección de la riqueza paleontológica y arqueológica, de tal manera que, permitiendo su utilización, no se ponga en peligro su existencia. Una visión sobre las normas legales, actividades e indicadores de desempeño relacionados con la labor del interventor ambiental de proyectos, la descripción de un plan de manejo ambiental, y el análisis de los procedimientos y etapas para la realización de una interventoría ambiental en proyectos de explotación petrolera, constituyen el tema central del presente trabajo.

Expression of neurotransmitters and neurotrophins in neurogenic inflammation of the rat retina

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E Bronzetti

2009-08-01

Full Text Available Antidromic stimulation of the rat trigeminal ganglion triggers the release of substance P (SP and calcitonin gene-related peptide (CGRP from sensory nerve terminals of the capsaicin sensitive C-fibers. These pro-inflammatory neuropeptides produce a marked hyperemia in the anterior segment of the eye, accompanied by increased intraocular pressure, breakdown of the blood-aqueous barrier and myosis. To assess the effects of neurogenic inflammation on the retina, specifically on the immunostaining of neurotransmitters and neurotrophins, as well as on the expression of neurotrophin receptors in the retina. RT-PCR was also accomplished in control and stimulated animals to confirm the immunohistochemical results. In the electrically stimulated eyes, immunostaining for SP, CGRP, VIP and nNOS demonstrated a marked increase in the RPE/POS (Retinal Pigment Epithelium/Photoreceptor Outer Segments, in the inner and outer granular layers and in the ganglion cells in comparison to the control eyes. CGRP and SP were found increased in stimulated animals and this result has been confirmed by RT- PCR. Changes in neurotrophin immunostaining and in receptor expression were also observed after electric stimulation of trigeminal ganglia. Decrease of BDNF and NT4 in the outer and inner layers and in ganglion cells was particularly marked. In stimulated rat retinas immunostaining and RT-PCR showed a NGF expression increase. Neurotrophin receptors remained substantially unchanged. These studies demonstrated, for the first time, that antidromic stimulation of the trigeminal ganglion and subsequent neurogenic inflammation affect immunostaining of retinal cell neurotransmitter/ neuropeptides and neurotrophins as well as the expression of neurotrophin receptors.

Vision drives correlated activity without patterned spontaneous activity in developing Xenopus retina.

Science.gov (United States)

Demas, James A; Payne, Hannah; Cline, Hollis T

2012-04-01

Developing amphibians need vision to avoid predators and locate food before visual system circuits fully mature. Xenopus tadpoles can respond to visual stimuli as soon as retinal ganglion cells (RGCs) innervate the brain, however, in mammals, chicks and turtles, RGCs reach their central targets many days, or even weeks, before their retinas are capable of vision. In the absence of vision, activity-dependent refinement in these amniote species is mediated by waves of spontaneous activity that periodically spread across the retina, correlating the firing of action potentials in neighboring RGCs. Theory suggests that retinorecipient neurons in the brain use patterned RGC activity to sharpen the retinotopy first established by genetic cues. We find that in both wild type and albino Xenopus tadpoles, RGCs are spontaneously active at all stages of tadpole development studied, but their population activity never coalesces into waves. Even at the earliest stages recorded, visual stimulation dominates over spontaneous activity and can generate patterns of RGC activity similar to the locally correlated spontaneous activity observed in amniotes. In addition, we show that blocking AMPA and NMDA type glutamate receptors significantly decreases spontaneous activity in young Xenopus retina, but that blocking GABA(A) receptor blockers does not. Our findings indicate that vision drives correlated activity required for topographic map formation. They further suggest that developing retinal circuits in the two major subdivisions of tetrapods, amphibians and amniotes, evolved different strategies to supply appropriately patterned RGC activity to drive visual circuit refinement. Copyright © 2011 Wiley Periodicals, Inc.

Un acercamiento hacia la caracterización del mercado potencial del aeropuerto de la Ciudad de Toluca, Estado de México

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María del Consuelo Méndez Sosa

2009-01-01

Full Text Available El presente artículo tiene como objetivo presentar las características del mercado potencial del aeropuerto internacional de la ciudad de Toluca, México, producto del proyecto de investigación- estudio de la oferta y demanda del mismo. Para el desarrollo de este proyecto se utilizó la corriente de pensamiento positivista y como método de trabajo la investigación de mercados propuesta por Philip Kotler; se manejó un muestreo no probabilístico por cuotas, determinando un total de 850 instrumentos aplicados en las principales plazas comerciales de las ciudades de Toluca, Metepec, Distrito Federal y zona conurbada, lo que permitió identificar el perfil del mercado potencial a través de variables demográficas, socioeconómicas, de conducta hacia el producto y psicográficas.

Characterisation of the metabolome of ocular tissues and post-mortem changes in the rat retina.

Science.gov (United States)

Tan, Shi Z; Mullard, Graham; Hollywood, Katherine A; Dunn, Warwick B; Bishop, Paul N

2016-08-01

Time-dependent post-mortem biochemical changes have been demonstrated in donor cornea and vitreous, but there have been no published studies to date that objectively measure post-mortem changes in the retinal metabolome over time. The aim of the study was firstly, to investigate post-mortem, time-dependent changes in the rat retinal metabolome and secondly, to compare the metabolite composition of healthy rat ocular tissues. To study post-mortem changes in the rat retinal metabolome, globes were enucleated and stored at 4 °C and sampled at 0, 2, 4, 8, 24 and 48 h post-mortem. To study the metabolite composition of rat ocular tissues, eyes were dissected immediately after culling to isolate the cornea, lens, vitreous and retina, prior to storing at -80 °C. Tissue extracts were subjected to Gas Chromatograph Mass Spectrometry (GC-MS) and Ultra High Performance Liquid Chromatography Mass Spectrometry (UHPLC-MS). Generally, the metabolic composition of the retina was stable for 8 h post-mortem when eyes were stored at 4 °C, but showed increasing changes thereafter. However, some more rapid changes were observed such as increases in TCA cycle metabolites after 2 h post-mortem, whereas some metabolites such as fatty acids only showed decreases in concentration from 24 h. A total of 42 metabolites were identified across the ocular tissues by GC-MS (MSI level 1) and 2782 metabolites were annotated by UHPLC-MS (MSI level 2) according to MSI reporting standards. Many of the metabolites detected were common to all of the tissues but some metabolites showed partitioning between different ocular structures with 655, 297, 93 and 13 metabolites being uniquely detected in the retina, lens, cornea and vitreous respectively. Only a small percentage (1.6%) of metabolites found in the vitreous were only detected in the retina and not other tissues. In conclusion, mass spectrometry-based techniques have been used for the first time to compare the metabolic composition of

Humedales: proyectos legislativos nacional y bonaerense : Definición e inventario

OpenAIRE

Romero, María Cristina

2017-01-01

Se describen los proyectos de Ley Nacional de Presupuestos Mínimos y de la Provincia de Buenos Aires para la protección y manejo de los humedales; y la situación de gestión para la realización de un inventario de los mismos tanto a nivel nacional como de la Provincia de Buenos Aires.

"Para derribar todas las fronteras": un proyecto realizado con inmigrantes latinoamericanos

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Lic. Laura Guillermina Moyano Ortiz

1998-01-01

Full Text Available Quería comentarles que este proyecto que comparto hoy con ustedes surge de una idea inicial gestada en el seno de una organización sin fines de lucro, de inspiración cristiana que, creo, algunos de ustedes conocerán probablemente de nombre: Cáritas Arquidiocesana de Córdoba, Argentina.

Localisation of the Putative Magnetoreceptive Protein Cryptochrome 1b in the Retinae of Migratory Birds and Homing Pigeons.

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Petra Bolte

Full Text Available Cryptochromes are ubiquitously expressed in various animal tissues including the retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a is so far the only cryptochrome protein that has been localised to specific cell types within the retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins, we show that Cry1b protein is found in the retinae of migratory European robins (Erithacus rubecula, migratory Northern Wheatears (Oenanthe oenanthe and pigeons (Columba livia. In all three species, retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.

Using induced pluripotent stem cell-derived conditional medium to attenuate the light-induced photodamaged retina of rats

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Hua-Ming Chang

2015-03-01

Conclusion: The conditional medium of iPSCs contains plenty of cytoprotective, immune-modulative and rescue chemicals, contributing to the maintenance of neuronal function and retinal layers in light-damaged retina compared with apoptotic iPSC-CM and PBS. The antiapoptotic effect of iPSC-CM also shows promise in restoring damaged neurons. This result demonstrates that iPSC-CM may serve as an alternative to cell therapy alone to treat retinal light damage and maintain functional and structural integrity of the retina.

The noncoding RNA taurine upregulated gene 1 is required for differentiation of the murine retina.

Science.gov (United States)

Young, T L; Matsuda, T; Cepko, C L

2005-03-29

With the advent of genome-wide analyses, it is becoming evident that a large number of noncoding RNAs (ncRNAs) are expressed in vertebrates. However, of the thousands of ncRNAs identified, the functions of relatively few have been established. In a screen for genes upregulated by taurine in developing retinal cells, we identified a gene that appears to be a ncRNA. Taurine Upregulated Gene 1 (TUG1) is a spliced, polyadenylated RNA that does not encode any open reading frame greater than 82 amino acids in its full-length, 6.7 kilobase (kb) RNA sequence. Analyses of Northern blots and in situ hybridization revealed that TUG1 is expressed in the developing retina and brain, as well as in adult tissues. In the newborn retina, knockdown of TUG1 with RNA interference (RNAi) resulted in malformed or nonexistent outer segments of transfected photoreceptors. Immunofluorescent staining and microarray analyses suggested that this loss of proper photoreceptor differentiation is a result of the disregulation of photoreceptor gene expression. A function for a newly identified ncRNA, TUG1, has been established. TUG1 is necessary for the proper formation of photoreceptors in the developing rodent retina.

Un acercamiento a los valores patrimoniales del edificio de la Facultad de Ingeniería de la Universidad de Costa Rica

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Rafael Ángel Venegas Arias

2018-01-01

Full Text Available Este ensayo es un acercamiento al edificio de la Facultad de Ingeniería en la Sede Rodrigo Facio Brenes de la Universidad de Costa Rica para su puesta en valor como patrimonio histórico-arquitectónico. Se hace una revisión histórica del inmueble y paralelamente se analizan distintos valores que pueden ser asignados al mismo, los cuales han sufrido un proceso de invisibilización. Los valores analizados en este ensayo son: simbólico, conjunto, objeto de diseño, documento histórico, espacio público y obra de arte; tomando en cuenta conceptos de política, historia, arquitectura e ideología. Para el desarrollo de este ensayo se utilizan los principios de la semiótica, abordando el edificio como un lenguaje que debe ser analizado e interpretado.

Peripheral Avascular Retina in a Term Male Neonate With Microvillus Inclusion Disease and Pancreatic Insufficiency.

Science.gov (United States)

Paulus, Yannis M; Alcorn, Deborah M; Gaynon, Michael; Moshfeghi, Darius M

2015-05-01

The authors present the first case of peripheral avascular retina in a term male neonate with pancreatic exocrine insufficiency, atypical microvillus inclusion disease, flat tympanograms, and recurrent urinary tract infections. Clinical examination showed avascular peripheral retina to posterior zone II temporally, with a flat stage 1-like demarcation line, and no plus disease. Genetic testing results were normal. The patient developed peripheral neovascularization and underwent panretinal photocoagulation. This case likely represents mild Norrie disease, familial exudative vitreoretinopathy, or incontinentia pigmenti due to a Wnt signaling abnormality. While these conditions are usually more severe, a variable spectrum of Wnt abnormalities exists throughout the body. Copyright 2015, SLACK Incorporated.

Cellular disturbance in the rats retina after irradiation and metabolic errors during the postnatal period

International Nuclear Information System (INIS)

Lierse, W.; Franke, H.D.

1982-01-01

During the first five days of the postnatal period the retina has been vulnerable following administration of DNA blocking drugs and irradiation with conventional X-rays and fast neutrons. During this period the disturbance of lamination accompanied with pycnosis of neurons and neuroblasts has been the important morphologic reaction. During the same phase metabolic errors, like experimental phenylketonuria, have produced a swelling of photoreceptor cells and pigmentepithelium cells. The other neurons of the retina were pycnotic. Structural alterations like rosettes persisted during the rest of life. The relative minor error during the first phase of rats life may result in a persistent disease. (orig.)

Plantillas y artefactos personalización de RUP para proyectos académicos de desarrollo de software

OpenAIRE

López Márquez, Mario Dario; Villa Palacio, Juan Camilo

2012-01-01

En este documento se encontrará información que presenta un marco teórico del proyecto de grado -- Dicho marco proveerá los objetivos generales y específicos, justificaciones, ejemplos y conclusiones que argumentarán el trabajo sobre el tema de metodologías ágiles orientadas a la academia -- El trabajo se realiza con el propósito presentar una serie de plantillas, artefactos y ejemplos cercanos a la vida real de proyectos de desarrollo de software usando la metodología EAFIT-UP (E...

Proyecto de Modernización de la Gestión de Recursos Hídricos: informe de factibilidad

OpenAIRE

Autoridad Nacional del Agua; Proyecto de Modernización de la Gestión de Recursos Hídricos

2009-01-01

Contiene el informe de factibilidad del Proyecto de Modernización de la Gestión de Recursos Hídricos (PMGRH), en este sentido presenta un resumen ejecutivo, aspectos generales y la formulación y evaluación del mismo. El objetivo del proyecto es fortalecer las capacidades de las instituciones responsables de la gestión de los recursos hídricos de nivel nacional, regional y local; para una eficiente y eficaz gestión de los recursos hídricos, procurando el aprovechamiento ambientalmente sostenib...

Proyecto Integral del río Cachi: estudio definitivo, obras 1era. fase (nivel licitación)

OpenAIRE

Corporación de Fomento y Desarrollo Económico y Social de Ayacucho

1984-01-01

Presenta un informe técnico que contiene el estudio a nivel licitación y que abarca las obras correspondientes a una primera fase de desarrollo del Proyecto integral río Cachi. En este sentido desarrolla los siguientes temas: información básica del proyecto, obras de derivación y trasvase, central hidroeléctrica Lambras, equipamiento electromecánico de la central, líneas de trasmisión, centros de transformación, sistemas de telecomunicaciones, caminos de acceso, programación y costo de las ob...

PROYECTO UNIHCOS COHORTE DINÁMICADE ESTUDIANTES UNIVERSITARIOS PARAELESTUDIO DELCONSUMO DE DROGAS Y OTRAS ADICCIONES

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Tania Fernández Villa

2013-01-01

Full Text Available elacionan con la adquisición y/o consolidación de estilos y hábitos de vida que pueden determinar el estado de salud futuro. Una inadecua- da nutrición, un alto nivel de sedentarismo, conductas sexuales de ries- go, el abuso de las nuevas tecnologías o el inicio en el consumo de dro- gas tanto legales como ilegales, son algunas de las conductas más destacables de esta etapa. Con el objeto de conocer cómo se establecen y consolidan los hábitos y estilos de vida en la etapa universitaria y sus efectos sobre la salud futura nace el proyecto uniHcos. Se trata del estu- dio de una cohorte dinámica de estudiantes universitarios que se incor- poran al proyecto durante el primer curso académico y serán seguidos durante su permanencia en la universidad y vida laboral. El seguimien- to se realizará bienalmente y para la captación y recogida de informa- ción se utilizarán las nuevas tecnologías on-line. El objetivo del presen- te trabajo es dar a conocer el proyecto uniHcos a la comunidad científica así como presentar los resultados preliminares encontrados hasta el momento en las dos cohortes establecidas desde el 2011.

Proyectos urbanos en mataderos: persistencias y rupturas en las propuestas sobre un barrio industrial

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Luján Menazzi

2009-12-01

Full Text Available Los planes y proyectos urbanos condensan miradas sobre la ciudad real y la ciudad deseada. Sugieren formas de intervenir y pensar la ciudad, refieren a modos de gestión y postulan ciertas transformaciones como deseables. Definen además, relaciones entre saberes y prácticas, entre lo público y lo privado y entre el estado y la sociedad. El presente trabajo se propone analizar una serie de proyecciones urbanas realizadas para el barrio de Mataderos, barrio industrial de la ciudad de Buenos Aires. Se trata de planes, ideas o proyectos, pensadas para el predio que quedaría luego del traslado del Mercado de Hacienda. Tomaré el concurso “Veinte ideas urbano-arquitectónicas para Buenos Aires” de 1986; el “Plan Urbano Ambiental” confeccionado entre 1997 y 2008; y el “Concurso Nacional de Ideas Urbanísticas del Área Sur” convocado en 2001. El eje de la reflexión será los posibles destinos que se ensayan para este sector de la ciudad y el perfil de ciudad que estos proyectos proponen. También se reflexionará acerca de los modos en que se propone operar sobre el barrio y los cambios en las modalidades de hacer y pensar la ciudad en contextos históricos, políticos y sociales diversos.

CMIN - herramienta case basada en CRISP-DM para el soporte de proyectos de minería de datos

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Carlos Cobos

2010-09-01

Full Text Available En este artículo se presenta la CMIN, una herramienta CASE (Computer Aided Software Engineering integrada (que soporta todas las fases de un proceso basada en CRISP-DM 1.0 (Cross – Industry Standard Process for Data Mining para soportar el desarrollo de proyectos de minería de datos.Primero se expone la funcionalidad general de CMIN, lo que incluye la gestión de procesos, plantillas y proyectos, y se destaca la capacidad de CMIN para realizar el seguimiento de los proyectos de una forma fácil e intuitiva y la manera como CMIN posibilita que el usuario incremente su conocimiento en el uso de CRISP-DM o de cualquier otro proceso que se defina en la herramienta a través de las ayudas e información que se ofrece en cada paso del proceso. Después, se detalla cómo CMIN permite enlazar en tiempo de ejecución (sin necesidad de volver a compilar la herramienta nuevos algoritmos de minería de datos que apoyen la labor de modelado (basada en un flujo de trabajo o workflow en un proyecto de minería de datos. Finalmente, se ofrecen los resultados de dos evaluaciones de la herramienta, las conclusiones y el trabajo futuro.

Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm.

Science.gov (United States)

Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

2014-12-01

We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same rats for four weeks. The images successfully demonstrated lipofuscin accumulation in the retinal pigment epithelium with aging. The experimental results showed that the dual-modal imaging system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

Análisis retrospectivo de los proyectos de ciencia, tecnología e innovación del subsector pecuario financiados por Colciencias, 1991-2010

OpenAIRE

Mónica María Baquero Parra; Edison Hernán Suárez Ortiz

2012-01-01

Entre las herramientas que ofrece Colciencias para lograr sus objetivos como entidad rectora del Sistema Nacional de Ciencia, Tecnología e Innovación, se encuentran las convocatorias públicas. El objetivo del presente trabajo es identificar y analizar los proyectos financiados por Colciencias durante el periodo 1991-2010 en temáticas correspondientes al subsector pecuario. Para esto se empleó la base de datos de registro de proyectos de Colciencias, a fin de identificar los proyectos del subs...

Consideraciones sobre la administración de proyectos de desarrollo de software, con ciclo de vida ágil, en el contexto costarricense

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Anayansie Fallas Badilla

2011-10-01

Full Text Available En Costa Rica, la adopción de metodologías ágiles para el desarrollo de software ha traído consigo nuevas interrogantes para los administradores de proyectos: ¿cómo planificar este tipo de proyectos?, ¿cómo darles control y seguimiento en su ejecución? ¿cuáles competencias son las deseables para quienes tengan que administrar este tipo de proyectos? Este artículo presenta un marco teórico al respecto, da un panorama general del desarrollo de software en Costa Rica y del profesional en tecnologías de la información con que cuenta el país, y a partir de lo anterior enumera una serie de consideraciones que puedan servir como guía para quien requiera administrar proyectos de desarrollo de software con este tipo de metodología en el contexto costarricense.

El Proyecto Genoma Humano: aspectos éticos

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Hernández Yago, José

1999-02-01

Full Text Available Not available.Todo conocimiento científico es positivo en cuanto que su contenido incrementa el control de la realidad. El desciframiento del genoma humano, con la consiguiente identificación y localización de los 50.000 a 100.000 genes que configuran su patrimonio genético, permitirá el progresivo esclarecimiento de los mecanismos reguladores de la expresión génica y pondrá al alcance del hombre posibilidades espléndidas, que requerirá años desentrañar. El acelerado ritmo en la caracterización de nuevos genes está desencadenando la posibilidad de pronosticar un número cada vez mayor de enfermedades genéticas y, por tanto, puede propiciar la práctica de una Medicina preventiva cada vez más rigurosa. Sin embargo, las posibles aplicaciones del conocimiento científico que aporta este proyecto suscitan también importantes inquietudes, desde el momento en que cada ser humano puede convertirse en un ser sin intimidad biológica. Por otra parte, la tecnología del ADN recombinante, al tiempo que aporta la enorme posibilidad de una futura terapia génica, suscita también legítimas preocupaciones sobre el correcto uso de estos conocimientos. En este artículo se abordan algunas de las cuestiones de carácter ético que ya plantea actualmente el Proyecto del Genoma Humano. Se adopta la perspectiva según la cual el respeto al patrimonio genético debería estar siempre presidido por un principio básico: no perder nunca de vista al hombre, esto es, al ser humano y su derecho a la identidad personal propia.

Survey of intravitreal injection techniques among retina specialists in Israel

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Segal O

2016-06-01

Full Text Available Ori Segal,1,2 Yael Segal-Trivitz,1,3 Arie Y Nemet,1,2 Noa Geffen,1,2 Ronit Nesher,1,2 Michael Mimouni4 1Department of Ophthalmology, Meir Medical Center, Kfar Saba, 2The Sackler School of Medicine, Tel Aviv University, Tel Aviv, 3Department of Psychiatry, Geha Psychiatric Hospital, Petah Tikva, 4Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel Purpose: The purpose of this study was to describe antivascular endothelial growth factor intravitreal injection techniques of retinal specialists in order to establish a cornerstone for future practice guidelines. Methods: All members of the Israeli Retina Society were contacted by email to complete an anonymous, 19-question, Internet-based survey regarding their intravitreal injection techniques. Results: Overall, 66% (52/79 completed the survey. Most (98% do not instruct patients to discontinue anticoagulant therapy and 92% prescribe treatment for patients in the waiting room. Three quarters wear sterile gloves and prepare the patient in the supine position. A majority (71% use sterile surgical draping. All respondents apply topical analgesics and a majority (69% measure the distance from the limbus to the injection site. A minority (21% displace the conjunctiva prior to injection. A majority of the survey participants use a 30-gauge needle and the most common quadrant for injection is superotemporal (33%. Less than half routinely assess postinjection optic nerve perfusion (44%. A majority (92% apply prophylactic antibiotics immediately after the injection. Conclusion: The majority of retina specialists perform intravitreal injections similarly. However, a relatively large minority performs this procedure differently. Due to the extremely low percentage of complications, it seems as though such differences do not increase the risk. However, more evidence-based medicine, a cornerstone for practice guidelines, is required in order to identify the intravitreal injection techniques

Distribution of FMRFamide-like immunoreactivity in the brain, retina and nervus terminalis of the sockeye salmon parr, Oncorhynchus nerka.

Science.gov (United States)

Ostholm, T; Ekström, P; Ebbesson, S O

1990-09-01

Neurons displaying FMRFamide(Phe - Met - Arg - Phe - NH2)-like immunoreactivity have recently been implicated in neural plasticity in salmon. We now extend these findings by describing the extent of the FMRF-like immunoreactive (FMRF-IR) system in the brain, retina and olfactory system of sockeye salmon parr using the indirect peroxidase anti-peroxidase technique. FMRF-IR perikarya were found in the periventricular hypothalamus, mesencephalic laminar nucleus, nucleus nervi terminalis and retina (presumed amacrine cells), and along the olfactory nerves. FMRF-IR fibers were distributed throughout the brain with highest densities in the ventral area of the telencephalon, in the medial forebrain bundle, and at the borders between layers III/IV and IV/V in the optic tectum. High densities of immunoreactive fibers were also observed in the area around the torus semicircularis, in the medial hypothalamus, median raphe, ventromedial tegmentum, and central gray. In the retina, immunopositive fibers were localized to the inner plexiform layer, but several fiber elements were also found in the outer plexiform layer. The olfactory system displayed FMRF-IR fibers in the epithelium and along the olfactory nerves. These findings differ from those reported in other species as follows: (i) FMRF-IR cells in the retina have not previously been reported in teleosts; (ii) the presence of FMRF-IR fibers in the outer plexiform layer of the retina is a new finding for any species; (iii) the occurrence of immunopositive cells in the mesencephalic laminar nucleus has to our knowledge not been demonstrated previously.

LA GESTIÓN DE PROYECTOS SOFTWARE, UNA PROSPECTIVA EN LA APLICACIÓN DE ESTRATEGIAS EN LA INGENIERÍA COLABORATIVA

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Jurado-Muñoz, José Luis

2013-06-01

Full Text Available La gestión de proyectos es una disciplina que integra diversas áreas de aplicación como la ingeniería, administración, economía, política, entre otras. Su interpretación y posterior ejecución es una tarea que demanda gran complejidad debido a la tecnicidad y alto número de sus procesos, el director de un proyecto de software y su equipo de apoyo debe tener no solo la experiencia en el campo sino el conocimiento pertinente para aplicar cualquiera de las metodologías que esta disciplina demanda para ser aplicada de la mejor manera. La falta de procedimientos y herramientas formales en su implementación impiden su acertada ejecución generando diversos problemas de índole administrativo y técnico que redundan en la calidad del producto entregado.. En este sentido, el presente artículo busca describir de una manera simplificada, la forma en que se podrían definir procedimientos y herramientas documentales de gestión de proyectos aplicando técnicas de la ingeniería de la colaboración, vistas desde la perspectiva de PMBOK como guía de referencia para la aplicación de buenas prácticas en gestión de proyectos. Asimismo, se presenta una breve descripción de la estructura interna de un modelo de mejora basado en PmCompetisoft, el cual garantiza el ajuste y adaptación de los procesos de gerencia de proyectos a un modelo de referencia establecido y el soporte de un modelo de evaluación para su validación respectiva

Review of Bassi & Hernández (2015, Formulaciones de proyectos de tesis en ciencias sociales

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Carlos Enrique Silva Rios

2016-03-01

Full Text Available Se reseña el libro Formulaciones de proyectos de tesis en ciencias sociales. Manual de supervivencia para estudiantes de pre- y posgrado, de Javier Bassi y Pablo Hernández. El punto de partida de los autores es una inconformidad con los manuales existentes. Para superar esa inconformidad, presentan como alternativa un texto que deja clara la necesidad de tener un posición epistemológica antes de comenzar a formular un proyecto de investigación. Luego, presentan una serie de requisitos, recomendaciones y ejemplos sobre cómo se realiza una tesis. Finalmente, ofrecen una guía sobre cómo redactar el producto final de la investigación.

Modulation of horizontal cell receptive fields in the light adapted goldfish retina

NARCIS (Netherlands)

Verweij, J.; Kamermans, M.; van den Aker, E. C.; Spekreijse, H.

1996-01-01

In the isolated goldfish retina, 700 nm background illumination increases the horizontal cell receptive field size, as measured with 565 nm slits of light, but decreases the receptive field size, when measured with 660 nm slits. These background-induced changes in receptive field size are absent

SISTEMA PARA LA ADMINISTRACIÓN DE MATERIALES EN PROYECTOS DE CONSTRUCCIÓN MASIVA DE VIVIENDA

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José Antonio González Fajardo

2002-07-01

Full Text Available Se propone un sistema para administrar los recursos materiales que intervienen en la construcción masiva de unidades habitacionales o vivienda unifamiliar. Esta propuesta es en sí, un planteamiento global de todas las etapas, fases y procesos administrativos que se consideran importantes integrar para llevar a cabo con éxito la función referida; se considera la administración de los materiales
desde el desarrollo del diseño del proyecto hasta su utilización dentro de los procesos constructivos, pasando a través de las etapas de planeación, programación y control de los mismos.Se estima haber alcanzado un alto nivel de detalle en cada una de las etapas que se definieron. Se aprovechan las características particulares de administración que se presentan en los proyectos de construcción masiva de vivienda, debido al carácter repetitivo de las unidades habitacionales.Para el desarrollo del sistema se tomaron en cuenta aspectos tales como la administración efectiva de proyectos y su impacto en la productividad de las empresas constructoras de este ramo, así como la situación actual, necesidades y opiniones de los ejecutivos de estas empresas.

Non-mydriatic video ophthalmoscope to measure fast temporal changes of the human retina

Science.gov (United States)

Tornow, Ralf P.; Kolář, Radim; Odstrčilík, Jan

2015-07-01

The analysis of fast temporal changes of the human retina can be used to get insight to normal physiological behavior and to detect pathological deviations. This can be important for the early detection of glaucoma and other eye diseases. We developed a small, lightweight, USB powered video ophthalmoscope that allows taking video sequences of the human retina with at least 25 frames per second without dilating the pupil. Short sequences (about 10 s) of the optic nerve head (20° x 15°) are recorded from subjects and registered offline using two-stage process (phase correlation and Lucas-Kanade approach) to compensate for eye movements. From registered video sequences, different parameters can be calculated. Two applications are described here: measurement of (i) cardiac cycle induced pulsatile reflection changes and (ii) eye movements and fixation pattern. Cardiac cycle induced pulsatile reflection changes are caused by changing blood volume in the retina. Waveform and pulse parameters like amplitude and rise time can be measured in any selected areas within the retinal image. Fixation pattern ΔY(ΔX) can be assessed from eye movements during video acquisition. The eye movements ΔX[t], ΔY[t] are derived from image registration results with high temporal (40 ms) and spatial (1,86 arcmin) resolution. Parameters of pulsatile reflection changes and fixation pattern can be affected in beginning glaucoma and the method described here may support early detection of glaucoma and other eye disease.

Institucionalidad en torno a los mercados de carbono y los mecanismos de flexibilización derivados del Protocolo de Kioto

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Piedad Patricia Restrepo

2008-01-01

Full Text Available El artículo presenta un acercamiento a las instituciones y regulaciones derivadas de la UNFCCC y el Protocolo de Kioto. Se analiza el comportamiento de los mercados de reducción de emisiones en sus ya casi tres años de funcionamiento, especialmente la inestabilidad de los precios en los diversos mercados europeos y su relación con los CER, estos últimos emitidos gracias a los proyectos provenientes del Mecanismo de Desarrollo Limpio (MDL desarrollados en los países en vías de desarrollo. Se establecen los alcances y limitaciones del MDL y finalmente se concluye acerca de las perspectivas de estos mercados y sus oportunidades.

Enfrentándonos a nuestros monstruos… el miedo como instrumento para entender el mundo

OpenAIRE

Montalvo Periane, Susana

2010-01-01

En las líneas que siguen, acompañaremos a un grupo de 25 niños y niñas de 4 años que junto a su maestra, se embarcan por primera vez en la aventura de aprender a aprender desde la perspectiva de los proyectos de trabajo y la investigación escolar. Quiere ser una experiencia de innovación escolar que busca la descripción de la práctica fundamentada en la teoría, en un intento de acercamiento a la construcción de un Conocimiento Práctico Profesional (Porlán R. 2008). In this paper, we will a...

Proyecto de mejora de la carretera BV-1415

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Gil Blázquez, Raúl; Jové Galobardes, Pau

2014-01-01

Este proyecto nace de la necesidad de mejorar la carretera BV-1415, unión entre los municipios de Cerdanyola del Vallès y Barcelona. Para ello, se propone el diseño de una nueva vía. Consiste en dar una alternativa viable a los habitantes de ambos municipios, ya que hasta hoy cuentan sólo con la autopista C-58, altamente transitada. Para llevarlo a cabo se ha realizado un levantamiento topográfico de la zona a trabajar, concretamente entre el punto kilométrico 2 y el 4, con la finalidad de...

The area centralis in the chicken retina contains efferent target amacrine cells

Science.gov (United States)

Weller, Cynthia; Lindstrom, Sarah H.; De Grip, Willem J.; Wilson, Martin

2012-01-01

The retinas of birds receive a substantial efferent, or centrifugal, input from a midbrain nucleus. The function of this input is presently unclear but previous work in the pigeon has shown that efferent input is excluded from the area centralis, suggesting that the functions of the area centralis and the efferent system are incompatible. Using an antibody specific to rods, we have identified the area centralis in another species, the chicken, and mapped the distribution of the unique amacrine cells that are the postsynaptic partners of efferent fibers. Efferent target amacrine cells are found within the chicken area centralis and their density is continuous across the border of the area centralis. In contrast to the pigeon retina then, we conclude that the chicken area centralis receives efferent input. We suggest that the difference between the 2 species is attributable to the presence of a fovea within the area centralis of the pigeon and its absence from that of the chicken. PMID:19296862

Proyectos de parcelas con servicios desarrollados por el INVI en la República Dominicana

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Pou Howley, Carlos

1984-07-01

Full Text Available Santo Domingo, the capital of the Dominican Republic, has not escaped the phenomenon of urban growth and the concentration of large slum areas or hovels, mainly due to the migratory movements of the peasants who have been driven from the country. As a viable solution to the enormous problem of housing in this city, INVI, with the participation of the World Bank, is putting forward projects for lots supplied with services in which infrastructure services are installed on urban land and plots or parcels of land are given to families so that they can build or complete their houses. These projects are located in places registering a greater tendency towards development. The urban plan formulated in both projects is of an eminently pedestrian nature with a reduced thoroughfare for vehicles. In the pedestrian precinct, it was possible to lay down what have been called mini-parks, which involve widening the pedestrian thoroughfare and, in addition to constituting green areas distributed throughout the projects, they also reinforce the idea of a neighbourhood. Because of the scope of the projects, a series of installations have been provided to maintain their own community services, as well as commercial and institutional ones, which are distributed strategically.Santo Domingo, capital de la República Dominicana, no ha escapado al fenómeno del crecimiento urbano y a la concentración de grandes tugurios o arrabales, debido principalmente a los movimientos migratorios de los campesinos expulsados del campo. Como una solución viable al gran problema de la vivienda de esta ciudad, el INVI, con la participación del Banco Mundial, plantea proyectos de parcelas con Servicios en los cuales se instalan servicios de infraestructura en tierras urbanas y se proporcionan parcelas o solares a familias para que éstas construyan o completen sus viviendas. Se ubican estos proyectos en sitios que acusan una mayor tendencia de desarrollo. El esquema urbano

James Monroe High School Proyecto Nuevos Horizontes, 1985-1986. OEA Evaluation Report.

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New York City Board of Education, Brooklyn. Office of Educational Assessment.

Proyecto Nuevos Horizontes, a 3-year Title VII-funded bilingual education program, serves 287 Spanish speaking students at James Monroe High School (Bronx, New York). This report evaluates the project's first year of operation, 1985-86. The report contains an introduction describing the school and project goals; information on student…

Protective effect of melatonin in the diabetic rat retina.

Science.gov (United States)

Mehrzadi, Saeed; Motevalian, Manijeh; Rezaei Kanavi, Mozhgan; Fatemi, Iman; Ghaznavi, Habib; Shahriari, Mansoor

2018-03-01

Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes. The aim of this study was to evaluate the effects of melatonin (MEL) on retinal injury in diabetic rats. In this study, 21 rats were randomly divided into three groups: control, diabetic, and diabetic + MEL. Streptozotocin was used to induce diabetes at a dose of 50 mg/kg, i.p., and blood glucose was measured to choose the diabetic rats for the study. MEL (20 mg/kg) was given orally for 7 weeks in diabetic rats starting 1 week after induction of diabetes. After 8 weeks, the groups were compared in terms of mean scores of fluorescein leakage, using fluorescein angiography. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were estimated in retina using commercially available assays. Structural changes in retinas were evaluated by light microscopy. Results showed that diabetes significantly increased the mean scores of fluorescein leakage, and MDA and ROS levels compared to control group. Treatment of the diabetic rats with MEL for 7 weeks prevented the alterations induced by diabetes in comparison with the diabetic control group.Based on these findings, it can be concluded that MEL might have beneficial effects in prevention of DR. © 2018 Société Française de Pharmacologie et de Thérapeutique.

Temporal resolution of misfolded prion protein transport, accumulation, glial activation, and neuronal death in the retinas of mice inoculated with scrapie

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Currently, there is a lack of pathologic landmarks to describe the progression of prion disease in vivo. The goal of this work was to determine the temporal relationship between the transport of misfolded prion protein from the brain to the retina, the accumulation of PrPSc in the retina, the respon...

Expanded progenitor populations, vitreo-retinal abnormalities, and Müller glial reactivity in the zebrafish leprechaun/patched2 retina

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Bibliowicz Jonathan

2009-10-01

Full Text Available Abstract Background The roles of the Hedgehog (Hh pathway in controlling vertebrate retinal development have been studied extensively; however, species- and context-dependent findings have provided differing conclusions. Hh signaling has been shown to control both population size and cell cycle kinetics of proliferating retinal progenitors, and to modulate differentiation within the retina by regulating the timing of cell cycle exit. While cell cycle exit has in turn been shown to control cell fate decisions within the retina, a direct role for the Hh pathway in retinal cell fate decisions has yet to be established in vivo. Results To gain further insight into Hh pathway function in the retina, we have analyzed retinal development in leprechaun/patched2 mutant zebrafish. While lep/ptc2 mutants possessed more cells in their retinas, all cell types, except for Müller glia, were present at identical ratios as those observed in wild-type siblings. lep/ptc2 mutants possessed a localized upregulation of GFAP, a marker for 'reactive' glia, as well as morphological abnormalities at the vitreo-retinal interface, where Müller glial endfeet terminate. In addition, analysis of the over-proliferation phenotype at the ciliary marginal zone (CMZ revealed that the number of proliferating progenitors, but not the rate of proliferation, was increased in lep/ptc2 mutants. Conclusion Our results indicate that Patched2-dependent Hh signaling does not likely play an integral role in neuronal cell fate decisions in the zebrafish retina. ptc2 deficiency in zebrafish results in defects at the vitreo-retinal interface and Müller glial reactivity. These phenotypes are similar to the ocular abnormalities observed in human patients suffering from Basal Cell Naevus Syndrome (BCNS, a disorder that has been linked to mutations in the human PTCH gene (the orthologue of the zebrafish ptc2, and point to the utility of the lep/ptc2 mutant line as a model for the study of BCNS

Proyecto seguridad en la construcción Honduras informe 2005 -2007

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Cálix, Darío; Hernández, Gabriela

2007-01-01

Con el fin de contribuir a la reducción de accidentes en el sector de la construcción en los países centroamericanos, el Programa Salud y Trabajo en América Central (SALTRA) ha desarrollado el Proyecto de "Prevención de Accidentes y Promoción de la Seguridad en el Sector de la Construcción". \

La industria textil del centro de México, un proyecto inconcluso de modernización económica (1830 – 1845

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Carlos Alberto Murgueitio

2015-01-01

Full Text Available El propósito de este trabajo es realizar una aproximación al primer proyecto industrialista mexicano, que abarca un periodo de quince años (1830-1845. Momento en el que los gobiernos de tendencia centralista emprendieron políticas orientadas a la modernización del sector textil a través del apoyo estatal, y de la promoción de políticas comerciales y fiscales de marcado acento proteccionista. El análisis se centrará en la evaluación objetiva del proyecto con el fin de comprender tanto sus aciertos y limitaciones, así como las dificultades que impidieron su consolidación El estudio está fundamentado tanto en la lectura e interpretación de las producciones académicas existentes sobre la materia, como en las memorias de personajes claves para el desarrollo del proyecto industrialista, como Lucas Alamán y Esteban Antuñano, así como de aquellos que lo criticaban, como José María Luis Mora y Mariano Otero. El artículo está dividido en tres partes, la primera trata de mostrar el contexto económico en el que surgió el proyecto industrialista, la segunda parte está dedicada a su implementación, y la tercera parte hace referencia al fracaso de dicho proyecto como resultado de la guerra contra los Estados Unidos de América.

Procesos de certificación de proyectos de captura de gases de efecto invernadero (GEI En los Mercados Internacionales de Carbono

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Sabogal Aguilar Javier

2011-11-01

Full Text Available En el marco de la mitigación al cambio climático, subyacen dos tipos de mecanismos destinados a disminuir las concentraciones de gases efecto invernadero: en primer lugar, la reducción de emisiones por las fuentes contaminantes; y en segundo lugar, el secuestro o captura de los gases de efecto invernadero (GEI cuantificados en CO2 equivalente en proyectos forestales (conocidos como LULUCF.Los proyectos de mitigación se abordan en el presente artículo por la comparación de los procesos de certificación que deben cumplir los proyectos de captura de gases de efecto invernadero, para acceder a los Mercados Internacionales de Carbono, tanto del Mecanismo de Desarrollo Limpio (MDL adoptado por el Protocolo de Kioto, como de los Mercados Voluntarios de Carbono (MVC.Como resultados, se presenta el aporte al desarrollo sustentable "local y regional": social, económico y ambiental en disponibilidad y mantenimiento de bienes y servicios ambientales; se resaltan las críticas a los esquemas de mercado analizados, y la incidencia del aporte a la sustentabilidad regional y local en la aprobación. De acuerdo con a lo anterior, los mercados voluntarios de carbono resultan ser más acordes con proyectos de pequeña y mediana escala mientras que el mecanismo de desarrollo limpio favorece en mayor medida aquellos proyectos de mediana y gran escala.