910 resultados para Vespucci, Amerigo, 1451-1512.


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Lake sturgeon (Acipenser fulvescens) were historically abundant in the Huron-Erie Corridor (HEC), a 160 km river/channel network composed of the St. Clair River, Lake St. Clair, and the Detroit River that connects Lake Huron to Lake Erie. In the HEC, most natural lake sturgeon spawning substrates have been eliminated or degraded as a result of channelization and dredging. To address significant habitat loss in HEC, multi-agency restoration efforts are underway to restore spawning substrate by constructing artificial spawning reefs. The main objective of this study was to conduct post-construction monitoring of lake sturgeon egg deposition and larval emergence near two of these artificial reef projects; Fighting Island Reef in the Detroit River, and Middle Channel Spawning Reef in the lower St. Clair River. We also investigated seasonal and nightly timing of larval emergence, growth, and vertical distribution in the water column at these sites, and an additional site in the St. Clair River where lake sturgeon are known to spawn on a bed of ~100 year old coal clinkers. From 2010-12, we collected viable eggs and larvae at all three sites indicating that these artificial reefs are creating conditions suitable for egg deposition, fertilization, incubation, and larval emergence. The construction methods and materials, and physical site conditions present in HEC artificial reef projects can be used to inform future spawning habitat restoration or enhancement efforts. The results from this study have also identified the likelihood of additional uncharacterized natural spawning sites in the St. Clair River. In addition to the field study, we conducted a laboratory experiment involving actual substrate materials that have been used in artificial reef construction in this system. Although coal clinkers are chemically inert, some trace elements can be reincorporated with the clinker material during the combustion process. Since lake sturgeon eggs and larvae are developing in close proximity to this material, it is important to measure the concentration of potentially toxic trace elements. This study focused on arsenic, which occurs naturally in coal and can be toxic to fishes. Total arsenic concentration was measured in samples taken from four substrate treatments submerged in distilled water; limestone cobble, rinsed limestone cobble, coal clinker, and rinsed coal clinker. Samples were taken at three time intervals: 24 hours, 11 days, and 21 days. ICP-MS analysis showed that concentrations of total arsenic were below the EPA drinking water standard (10 ppb) for all samples. However, at the 24 hour sampling interval, a two way repeated measures ANOVA with a Holm-Sidak post hoc analysis (α= 0.05) showed that the mean arsenic concentration was significantly higher in the coal clinker substrate treatment then in the rinsed coal clinker treatment (p=0.006), the limestone cobble treatment (p

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Melanocytes, pigment-producing cells, derive from the neural crest (NC), a population of pluripotent cells that arise from the dorsal aspect of the neural tube during embryogenesis. Many genes required for melanocyte development were identified using mouse pigmentation mutants. The deletion of the transcription factor Ets1 in mice results in hypopigmentation; nevertheless, the function of Ets1 in melanocyte development is unknown. The goal of the present study was to establish the temporal requirement and role of Ets1 in murine melanocyte development. In the mouse, Ets1 is widely expressed in developing organs and tissues, including the NC. In the chick cranial NC, Ets1 is required for the expression of Sox10, a transcription factor critical for the development of melanocytes, enteric ganglia, and other NC derivatives. Using a combination of immunofluorescence and cell survival assays Ets1 was found to be required between embryonic days 10 and 11, when it regulates NC cell and melanocyte precursor (melanoblast) survival. Given the requirement of Ets1 for Sox10 expression in the chick cranial NC, a potential interaction between these genes was investigated. Using genetic crosses, a synergistic genetic interaction between Ets1 and Sox10 in melanocyte development was found. Since Sox10 is essential for enteric ganglia formation, the importance of Ets1 on gut innervation was also examined. In mice, Ets1 deletion led to decreased gut innervation, which was exacerbated by Sox10 heterozygosity. At the molecular level, Ets1 was found to activate a Sox10 enhancer critical for Sox10 expression in melanoblasts. Furthermore, mutating Ets1 at a site I characterized in the spontaneous variable spotting mouse pigmentation mutant, led to a 2-fold decrease in enhancer activation. Overexpression and knockdown of Ets1 did not affect Sox10 expression; nonetheless, Ets1 knockdown led to a 6-fold upregulation of the transcription factor Sox9, a gene required for melanocyte and chondrocyte development, but which impairs melanocyte development when its expression is prolonged. Together, these results suggest that Ets1 is required early during melanocyte development for NC cell and melanoblast survival, possibly acting upstream of Sox10. The transcription factor Ets1 may also act indirectly in melanocyte fate specification by repressing Sox9 expression, and consequently cartilage fate.

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Introducción: Entre las diferentes herramientas clínicas para evaluar la presencia de enfermedad coronaria mediante puntajes, la más usada es la Escala de Riesgo cardiovascular de Framingham. Desde hace unos años, se creó el puntaje de calcio coronario el cual mide el riesgo cardiovascular según la presencia de placas ateromatosas vistas por tomografía computarizada. Se evaluó la asociación entre la escala de Framigham y el puntaje de calcio coronario en una población de sujetos sanos asintomáticos. Metodología: Se realizó un estudio transversal para evaluar la asociación entre el puntaje de calcio coronario y la escala de Framingham en sujetos asintomáticos que se practicaron exámen médico preventivo en la Fundación Cardioinfantil- Instituto de Cardiología (FCI-IC) en el periodo comprendido entre 1 de Julio 2011 hasta el 31 de octubre de 2015. Resultados: Se evaluaron 262 pacientes en total. La prevalencia de riesgo cardiovascular fue bajo en un 77.86% de la población, medio en 18.70% y alto en 3.44%, según la escala de Framingham. El riesgo cardiovascular según el puntaje de Calcio coronario fue nulo 70.99%, bajo en 21.75%, medio en 4.19%, severo en 3.05%. Se encontró una asociación entre ambos puntajes para riesgo estadísticamente significativa (p0,00001) Discusión: El riesgo cardiovascular establecido por escala de Framingham se relaciona de forma significativa con la presencia de placas aterioscleróticas. El estudio demostró que en una muestra de sujetos asintomáticos, hay una alteración estructural coronaria temprana.

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El Boletín Tendencia Editorial es un proyecto que nació en 2010 con motivo de la Feria Internacional del Libro de Bogotá para construir y hacer visibles diferentes saberes desde la academia y la edición. Para 2014, el cambio de periodicidad coincidió con uno de los eventos más importantes para la edición universitaria, la Feria Internacional del Libro de Guadalajara donde anualmente se realiza el encuentro de Editores Universitarios Latinoamericanos, el proyecto pasó de su fase nacional a ser pensado en red. Las líneas temáticas traspasan fronteras locales y convocan, en un mismo espacio, las voces de los gestores y especialistas, cuya labor y experiencia permiten cada día mejorar la edición universitaria, lo que posibilita acabar con el mito que concibe a la Universidad como ente ajeno a la sociedad, cuando en realidad esta es la forjadora de líderes, investigadores y emprendedores.

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La concepción de Estado moderno está íntimamente vinculada al ejercicio del monopolio legítimo de la fuerza, en tanto supone que la violencia es una de las principales prerrogativas que el Estado pretende detentar, para constituirse en una organización política de poder que perdure en la sociedad en la que se instaura. En este sentido, el proyecto de investigación tiene como uno de sus objetivos específicos, identificar, caracterizar y analizar los daños antijurídicos por los cuales el Comité de Conciliación del Ministerio de Defensa Nacional autoriza el ejercicio de la acción de repetición contra los funcionarios o ex-funcionarios de las Fuerzas Militares, limitando el análisis al periodo transcurrido durante los años 2010 a 2016. Lo anterior, con el fin de establecer cuáles son las causas generadoras de responsabilidad más frecuentes en las que han incurrido los agentes de la entidad, para luego observar su impacto en el erario de la nación y verificar cómo se constituyen en una necesidad de imposición de límites al ejercicio de la fuerza del Estado.

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Em 1512 Gil Vicente levou ao palco o seu Auto do Velho da Horta, anunciado como farsa na didascália inicial. O género e também o enredo aí resumido (os amores de um velho por uma moça, os enganos da alcoviteira) prefiguram uma peça cómica e prometem risos. Revemos neste artigo alguns aspetos do cómico na peça, à luz da bibliografia e das diferentes leituras de que foi objeto. Julgamos que persistem interrogações pertinentes sobre a prevalência, ou não, da dimensão lúdica da peça, veículo facilitador da ação moralizadora que se pretendia exercer no espaço da corte, e sobre uma matriz mais universalista que lhe está subjacente na abordagem de tópicos literários como o do mundo às avessas ou o da loucura amorosa.

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Community participation has been considered strategic in order to achieve effectiveness in political, economical, social, educational and cultural change processes as a mean of guarantying effectiveness, quality and sustainability in social policy. Accordingly, this participation must be stimulated and promoted through national legislation since it has traditionally and historically been imposed and undemocratic. Education, as an essentially human act, is a first order instrument that societies must take advantage of in order to develop and stimulate democratic participation. Therefore, education may represent a new culture: one of democratic participation as a fundamental way to empower and develop a Peace culture.

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Recibido 26 de octubre de 2009 • Aceptado 02 de diciembre de 2009 • Corregido 17 de febrero de 2010 En el constante cambio que vivimos, la Pedagogía, en tanto ciencia de la educación, ciencia de la relacionalidad entre seres humanos, es el producto de acuerdos, de procesos comunicativos, procesos socioculturales entrelazados de forma compleja. La atención a la diversidad es una preocupación creciente en ambientes y sociedades plurales, y el lenguaje, como rasgo cultural permite describir nuestras circunstancias y reflexionar sobre ellas para comprenderlas, redimensionar el presente, valorar el pasado e imaginar el futuro. Si tenemos en cuenta que el habla es sólo una de las manifestaciones del lenguaje, si las diversas formas de expresión del cuerpo constituyen formas de lenguaje, se impone la necesidad de pensar cómo nos comunicamos en los procesos pedagógicos.

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The purpose of this essay is to raise the educational development that has been experienced in our country, outlining influential frames such as political, social, religious and economical ones. It aims to report statistical data as indicators of the development of our educational system, in areas of coverage, average education, repetition, desertion, among others. It is imperative to achieve changes and restructuring in our education system at all levels, from kindergarten to university, so it should take into account the contribution of all stakeholders in the education sector, as the human resource is valuable and all the innovative proposals should be heard, especially those that seek to build together and not ideas imposed that hinder the development of education in our country. Improvements must be necessary because there is an existing desire by many people of improving and achieving a true enrichment in our education.