931 resultados para Murillo, Bartolomé Esteban, 1617-1682.


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Socio-economic development in Europe has exerted increasing pressure on the marine environment. Eutrophication, caused by nutrient enrichment, is evident in regions of all European seas. Its severity varies but has, in places, adversely impacted socio-economic activities. This paper aims to evaluate the effectiveness of recently adopted policies to reduce anthropogenic nutrient inputs to European seas. Nitrogen and phosphorus budgets were constructed for three different periods (prior to severe eutrophication, during severe eutrophication and contemporary) to capture changes in the relative importance of different nutrient sources in four European seas suffering from eutrophication (Baltic Proper, coastal North Sea, Northern Adriatic and North-Western Black Sea Shelf). Policy success is evident for point sources, notably for P in the Baltic and North Seas, but reduction of diffuse sources has been more problematic.

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We present the first remotely operated vehicle investigation of megabenthic communities (1004-1695 m water depth) on the Hebrides Terrace Seamount (Northeast Atlantic). Conductivity-temperature-depth casts showed rapid light attenuation below the summit and an oceanographic regime on the flanks consistent with an internal tide, and high short-term variability in water temperature, salinity, light attenuation, aragonite and oxygen down to 1500 m deep. Minor changes in species composition (3-14%) were explained by changes in depth, substratum and oceanographic stability, whereas environmental variability explained substantially more variation in species richness (40-56%). Two peaks in species richness occurred, the first at 1300-1400 m where cooler Wyville Thomson Overflow Water (WTOW) mixes with subtropical gyre waters and the second at 1500-1600 m where WTOW mixes with subpolar mode waters. Our results suggest that internal tides, substrate heterogeneity and oceanographic interfaces may enhance biological diversity on this and adjacent seamounts in the Rockall Trough.

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Se aportan datos del hábitat y distribución de diez especies del género Melanelia y cinco del género Neofuscelia en el Centro de España (provincias de Avila, Madrid y Segovia). Consideramos que son nuevas citas: Melanelia disjunta, M. elegantula y Neofuscelia delisei, para la provincia de Avila; y M. subargentifera, M. tominii, N. delisei, N. glabrans y N. verruculifera, para la provincia de Madrid. Además. se ha elaborado una clave para la identificación de estas especies.

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Se estudia la influencia de los siguientes factores sobre el valor del cociente de feofitinización DO 435 nm/DO 415 nm en el líquen Anaptychia ciliaris (L.) Kórber: edad del líquen, concentración final de pigmentos, trasplante de los líquenes a áreas distintas sobre sustratos diferentes o similares y el valor de pH del sustrato original o el adoptado tras el trasplante. Se discute la utilización de A. ciliaris como un bioindicador de la presencia de factorcs acidificantes en la atmósfera o en el agua de lluvia que provoquen la feofitinización de las clorofilas.

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Se describen los caracteres químicos encontrados en ejemplares de Evernia prunastri (L.) Ach.y Parmelina tiliacea (Hoffm.) Hale recogidos en la provincia de Madrid siguiendo un gradiente altitudinal.

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Se estudia la distribución peninsular y la composición en derivados del b-orcinol de Melanelia acetabulum (Neck.) Essl. Las muestras mediterráneas analizadas presentan constantemente ácidos connorestícticos y norestíctico, careciendo de ácido salacínico y atranorina. Las muestras de la única localidad eurosiberiana estudiada presentan las mismas depsidonas, pero además contienen pequeñas cantidades de atranorina. Se discute, en base a estos resultados, la relación entre Melanelia acetabulum y M. koflerae (Clauzade & Poelt) Essl.

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El uso de agroquímicos en Argentina se ha fortalecido junto con la expansión agrícola. El objetivo de este trabajo es la elaboración de una metodología para calcular el impacto ambiental que los pesticidas causan en el medio ambiente teniendo en cuenta los siguientes factores: "ecotoxicología": categoría toxicológica, toxicidad en abejas, aves y peces; "Toxicidad humana": carcinogenicidad, neurotoxicidad, alteraciones endocrinas, genotoxicidad y capacidad irritativa; "Comportamiento ambiental": la persistencia en el agua / sedimento, persistencia en el suelo y bioconcentración. Estos factores fueron clasificados como bajo, medio, alto o muy alto, de acuerdo con su nivel de toxicidad. Los resultados indican que los plaguicidas más tóxicos son los insecticidas. La mayoría de los pesticidas utilizados son la toxicidad media (43,75%), seguido de baja y alta toxicidad (21,88%) y, los de muy alta toxicidad (12,5%). La metodología propuesta podría ser utilizada como una herramienta de monitoreo, gestión o educación ambiental.

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Capacitation is essential for fertilization of ovulated oocytes. Capacitation is correlated with activation of a signal transduction pathway leading to protein tyrosine phosphorylation, an essential prerequisite for fertilization. Oviductin has been shown to bind to the acrosomal cap and the equatorial segment region of the sperm head. In light of findings reported in previous studies, we hypothesized that estrus stage-specific oviductin (EOV) enhances tyrosine phosphorylation. Immunofluorescent detection by light and confocal microscopy and immunogold labeling by electron microscopy and surface replica techniques were used to localize tyrosine phosphorylated proteins to the equatorial segment region and midpiece after incubation in medium in the presence or absence of EOV. In the presence of EOV, an increase in tyrosine phosphorylation in the equatorial segment region was observed as early as 5 minutes after incubation. On prolonging incubation in medium containing EOV immunostaining further increased, indicative of increased levels of tyrosine phosphorylation of sperm proteins as capacitation proceeds. Regardless of the presence or absence of EOV, phosphotyrosine expression was observed along the tail, specifically at the midpiece. However, this reactivity was enhanced in the presence of EOV. Western blot analysis of NP-40 extractable and non-extractable sperm proteins confirmed these observations. NP-40 extractable sperm proteins (25, 37, 44kDa) and non-extractable sperm proteins (70, 83, 90kDa) showed increased intensity when sperm were capacitated in the presence of EOV after 5-, 60-, 120- and 180-minutes of capacitation. Mass spectrophotometric analysis identified enolase, ATP-specific succinyl CoA, succinate CoA ligase, zona pellucida binding protein, heat shock protein 90, aconitase and hexokinase as proteins that undergo enhancement in tyrosine phosphorylation in the presence of EOV. The proteins identified are known to be involved in specific functions including cellular metabolism, molecular chaperoning and normal sperm development. In summary, the present investigation has provided new evidence showing that sperm capacitated in vitro in the presence of EOV display an enhanced expression of tyrosine phosphorylation compared to sperm incubated in capacitating medium alone. These results indicate that inclusion of oviductin in media used for in vitro fertilization (IVF) may improve success rates of IVF by enhancing the signaling pathways involved in sperm capacitation.

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La información es el elemento primordial en una Institución, sea del carácter que sea. Fluye de cualquier departamento que la integra y esta información hay que recopilarla, ordenarla, sintetizarla, tratarla y por último y más relevante hay que distribuirla. No se puede retener ni ocultar, se debe canalizar para que todos los integrantes de esa empresa la conozcan, la entiendan, la asuman y la hagan suya. Es así como funcionan bien los organismos conociendo lo que trabajan, sus objetivos, sus límites, sus avances y sus logros. Los gabinetes de comunicación son el motor de la documentación. Gestionan los contenidos, crean archivos de datos y documentos y difunden la información, no solo entre los diferentes componentes de la empresa sino también entre los distintos estamentos de la sociedad, proyectando al exterior la imagen de la Institución para la que trabajan.

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The journalistic boom that occurred in Argentina from the second half of the nineteenth century saw the emergence of an active afroporteña press that defend the interests of the black community. This paper, in addition to reviewing the history of the Afro-Argentines newspapers, emphasizes the role played by the elite of African descent in the promotion of modernity among his brothers, while exploring the possible bases for an identity in the ideas spread.

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This paper aims to demonstrate how in the constitutional rule of law the right of resistance plays a key role in its development, its adaptation to the changing reality of society and the satisfaction of the interests of all the people involved in this common project. Firstly, we will analyze how individuals or social groups must act when they suffer injustices due to state acts or laws that violate their most basic rights. In some cases, we believe that they have the right to exercise any form of weak resistance that they deem appropriate to present at the public scene a cause that must be socially and politically recognized. Secondly, we will see what happens when the rule of law itself is in danger. In that case, we believe that society will have not only the right but the duty to exercise the resistance in its most extreme form to defend the existing constitutional order of any illegitimate authority that seeks to impose itself on it and the sovereignty of the people.

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The aim of this article is to analyze the social policy in Latin America in a context of emerging welfare states. To understand the changes one takes into consideration the theories about institutional reform and the transformations produced in the XX century and the beginning of the XXI to substitute a social security regime mainly based on segmentation of benefi ts and on programs to fi ght poverty by another with an institutional and redistributive nature. The paper pays attention in particular to the path of the most developed welfare states of Latin America: Costa Rica, Chile, Argentina, Brasil y Uruguay.