787 resultados para SFS-EN ISO 3834


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Age-related macular degeneration, a major cause of blindness for which no satisfactory treatments exist, leads to a gradual decrease in central high acuity vision. The accumulation of fluorescent materials, called lipofuscin, in retinal pigment epithelial cells of the aging retina is most pronounced in the macula. One of the fluorophores of retinal pigment epithelial lipofuscin has been characterized as A2E, a pyridinium bis-retinoid, which is derived from two molecules of vitamin A aldehyde and one molecule of ethanolamine. An investigation aimed at optimizing the in vitro synthesis of A2E has resulted in the one-step biomimetic preparation of this pigment in 49% yield, readily producing more than 50 mg in one step. These results have allowed for the optimization of HPLC conditions so that nanogram quantities of A2E can be detected from extracts of tissue samples. By using 5% of the extract from individual aged human eyes, this protocol has led to the quantification of A2E and the characterization of iso-A2E, a new A2E double bond isomer; all-trans-retinol and 13-cis-retinol also have been identified in these HPLC chromatograms. Exposure of either A2E or iso-A2E to light gives rise to 4:1 A2E:iso-A2E equilibrium mixtures, similar to the composition of these two pigments in eye extracts. A2E and iso-A2E may exhibit surfactant properties arising from their unique wedge-shaped structures.

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The isozyme form of eukaryotic initiation factor 4F [eIF-(iso)4F] from wheat germ is composed of a p28 subunit that binds the 7-methylguanine cap of mRNA and a p86 subunit having unknown function. The p86 subunit was found to have limited sequence similarity to a kinesin-like protein encoded by the katA gene of Arabidopsis thaliana. Native wheat germ eIF-(iso)4F and bacterially expressed p86 subunit and p86-p28 complex bound to taxol-stabilized maize microtubules (MTs) in vitro. Binding saturation occurred at 1 mol of p86 per 5-6 mol of polymerized tubulin dimer, demonstrating a substoichiometric interaction of p86 with MTs. No evidence was found for a direct interaction of the p28 subunit with MTs. Unlike kinesin, cosedimentation of eIF-(iso)4F with MTs was neither reduced by MgATP nor enhanced by adenosine 5'-[gamma-imido]triphosphate. Both p86 subunit and p86-p28 complex induced the bundling of MTs in vitro. The p86 subunit was immunolocalized to the cytosol in root maize cells and existed in three forms: fine particles, coarse particles, and linear patches. Many coarse particles and linear patches were colocalized or closely associated with cortical MT bundles in interphase cells. The results indicate that the p86 subunit of eIF-(iso)4F is a MT-associated protein that may simultaneously link the translational machinery to the cytoskeleton and regulate MT disposition in plant cells.

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En la presente tesis se propone un modelo de gestión de redes que incorpora en su definición la gestión y difusión masiva de la información sobre redes no propietarias como Internet. Este modelo viene a solucionar uno de los problemas más comunes para cualquier aplicación, tanto de gestión como de usuario, proporcionando un mecanismo sencillo, intuitivo y normalizado para transferir grandes volúmenes de información, con independencia de su localización o los protocolos de acceso. Algunas de las características más notables del modelo se pueden sintetizar en las siguientes ideas. La creación de herramientas siguiendo el modelo permite que los desarrolladores de aplicaciones puedan centrarse en la lógica de la aplicación, en lugar de tener que resolver, generalmente a medida, el problema de la transferencia de grandes volúmenes de información. El modelo se ha concebido para ser compatible con los estándares existentes, tomando como base el marco de trabajo definido por ISO/IEC para sistemas OSI. Para que la difusión de la información se realice de forma escalable y con el menor impacto posible sobre la red de comunicaciones se ha propuesto un método de difusión fundamentando en técnicas colaborativas y de multicast. Las principales áreas de aplicaciones del modelo se encuentran en: los sistemas de gestión como las copias de seguridad en red, sistemas para la continuidad en el negocio y alta disponibilidad o los sistemas de mantenimiento de redes de computadoras; aplicaciones de usuario como las aplicaciones eBusiness, sistemas de compartición de archivos o sistemas multimedia; y, en general, cualquier tipo de aplicación que conlleve la transferencia de importantes volúmenes de información a través de redes de área amplia como Internet. Los principales resultados de la investigación son: un modelo de gestión de redes, un mecanismo de difusión de la información concretado en un protocolo de transporte y otro de usuario y una librería que implementa los protocolos propuestos. Para validar la propuesta se ha construido un escenario de pruebas real y se ha implementado el prototipo de un sistema de recuperación integral de nodos basado en el modelo y utilizando las librerías creadas. Las pruebas de escalabilidad, carga y tiempos de transferencia realizados sobre el prototipo han permitido verificar la validez e idoneidad de la propuesta comprobando que su aplicación es escalable respecto del tamaño del sistema gestionado, sencillo de implantar y compatible con los sistemas existentes.

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Criterios de conformidad de la Norma Técnica Ecuatoriana NTE INEN-ISO/IEC 40500 que se deben tener en cuenta durante la fase de diseño de un sitio web. Estos criterios se deben tener en cuenta antes de la codificación de una página web, durante su diseño visual mediante la creación de prototipos visuales (mockups).

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Esta base de datos es uno de los resultados obtenidos durante la realización del Trabajo Fin de Grado del Grado de Ingeniería Informática de la Universidad de Alicante, de la alumna Patricia Pérez Sallán y dirigido por el Dr. José Vicente Berná Martínez.

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The study of the Neogene (Miocene to Holocene) stratigraphic record on the glaciated Atlantic margin of NW Europe has, to date, largely been undertaken on an ad-hoc basis. Whereas a systematic approach to understanding the stratigraphic development of Palaeogene and older strata has been undertaken in areas such as the North Sea, West of Shetland and Norway, the problem of establishing a Neogene framework has been only partly addressed by academia and the oil industry. In most cases where a Neogene stratigraphy has been constructed, this has been largely in response to problem solving and risk assessment in a restricted area. Nevertheless, in the past few years it has become increasingly apparent that there is a common history in the Neogene development of the passive Atlantic margin of NW Europe, between mid-Norway and SW Ireland. The inspection and interpretation of an extensive geophysical and geological database has identified several regionally significant and correlatable unconformities along this continental margin. Thus, a regional approach to the stratigraphical development of the Neogene succession on the glaciated European Atlantic margin is undertaken in this volume.

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2002 Mathematics Subject Classification: 62P30, 62P10.

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This research inquires into the value of two common ‘management technologies’, namely ISO 9001 and project management. To avoid certain methodological problems, we study the value of these micro-level practices by inductively analysing macro-level data, specifically the intensity of project management and ISO 9001 certification (termed project management score and ISO 9001 score) in different countries against national measures of wealth and innovation. There is no correlation between ISO 9001 score and innovation, while high ISO 9001 scores are correlated with decreasing levels of wealth. The project management score is positively correlated with wealth and with innovation, though very high project management scores are negatively correlated with innovation. The study includes a cluster analysis which finds that, with one exception, countries tend to adopt either project management or ISO 9001 but not both. The analysis indicates that project management is more likely to be associated with high innovation and high wealth than ISO 9001.

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We describe the contemporary hydrography of the pan-Arctic land area draining into the Arctic Ocean, northern Bering Sea, and Hudson Bay on the basis of observational records of river discharge and computed runoff. The Regional Arctic Hydrographic Network data set, R-ArcticNET, is presented, which is based on 3754 recording stations drawn from Russian, Canadian, European, and U.S. archives. R-ArcticNET represents the single largest data compendium of observed discharge in the Arctic. Approximately 73% of the nonglaciated area of the pan-Arctic is monitored by at least one river discharge gage giving a mean gage density of 168 gages per 106 km2. Average annual runoff is 212 mm yr?1 with approximately 60% of the river discharge occurring from April to July. Gridded runoff surfaces are generated for the gaged portion of the pan-Arctic region to investigate global change signals. Siberia and Alaska showed increases in winter runoff during the 1980s relative to the 1960s and 1970s during annual and seasonal periods. These changes are consistent with observations of change in the climatology of the region. Western Canada experienced decreased spring and summer runoff.

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The aim of this paper is to deepen in the terminology of Records Management established by ISO standards, through a concrete example such as an interlinguistic comparison between UNE ISO 15489-1 and DIN ISO 15489-1, that is, between the Spanish and German versions of the ISO 15489-1. For that, the text is divided into two major and complementary parts, which are similar to both analytical perspectives adopted: the semantic one and the pragmatic one. The first one compares the words per se, taking into account the significant or word form as well as the significance or meaning. In the second part, examples of use from both languages are discussed, concerning the three terms considered essential in the text (Record, Records Management System and Records Management). The main conclusion lies in understanding how important the language is as a discrete tool of work for all information scientists, specially concerning to the standards, where the translators must show their best linguistic strategies to go unnoticed.

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Single-page applications have historically been subject to strong market forces driving fast development and deployment in lieu of quality control and changeable code, which are important factors for maintainability. In this report we develop two functionally equivalent applications using AngularJS and React and compare their maintainability as defined by ISO/IEC 9126. AngularJS and React represent two distinct approaches to web development, with AngularJS being a general framework providing rich base functionality and React a small specialized library for efficient view rendering. The quality comparison was accomplished by calculating Maintainability Index for each application. Version control analysis was used to determine quality indicators during development and subsequent maintenance where new functionality was added in two steps. The results show no major differences in maintainability in the initial applications. As more functionality is added the Maintainability Index decreases faster in the AngularJS application, indicating a steeper increase in complexity compared to the React application. Source code analysis reveals that changes in data flow requires significantly larger modifications of the AngularJS application due to its inherent architecture for data flow. We conclude that frameworks are useful when they facilitate development of known requirements but less so when applications and systems grow in size. Sammanfattning: Ensidesapplikationer har historiskt sett påverkats av starka marknadskrafter som pådriver snabba utvecklingscykler och leveranser. Detta medför att kvalitetskontroll och förändringsbar kod, som är viktiga faktorer för förvaltningsbarhet, blir lidande. I denna rapport utvecklar vi två funktionellt ekvi-valenta ensidesapplikationer med AngularJS och React samt jämför dessa applikationers förvaltningsbarhet enligt ISO/IEC 9126. AngularJS och React representerar två distinkta angreppsätt på webbutveckling, där AngularJS är ett ramverk med mycket färdig funktionalitet och React ett mindre bibliotek specialiserat på vyrendering. Kvalitetsjämförelsen utfördes genom att beräkna förvaltningsbarhetsindex för respektive applikation. Versionshanteringsanalys användes för att bestämma andra kvalitetsindikatorer efter den initiala utvecklingen samt två efterföljande underhållsarbeten. Resultaten visar inga markanta skillnader i förvaltningsbarhet för de initiala applikationerna. I takt med att mer funktionalitet lades till sjönk förvaltnings-barhetsindex snabbare för AngularJS-applikationen, vilket motsvarar en kraftigare ökning i komplexitet jämfört med React-applikationen. Versionshanteringsanalys visar att ändringar i dataflödet kräver större modifikationer för AngularJS-applikationen på grund av dess förbestämda arkitektur. Utifrån detta drar vi slutsatsen att ramverk är användbara när de understödjer utvecklingen mot kända krav men att deras nytta blir begränsad ju mer en applikation växer i storlek.

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Full Text / Article complet

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Programa de doctorado: Ingeniería ambiental y desalinización. La fecha de publicación es la fecha de lectura