4 resultados para Two-photon sources
em Acceda, el repositorio institucional de la Universidad de Las Palmas de Gran Canaria. España
Resumo:
[ES]El spam, o correo no deseado enviado masivamente, es una amenaza que afecta al correo electrónico y otros medios de comunicación telemática. Su alto volumen de circulación genera pérdidas temporales y económicas considerables. Se presenta una solución a este problema: un sistema inteligente híbrido de filtrado antispam, basado en redes neuronales artificiales (RNA) no supervisadas. Consta de una etapa de preprocesado y de otra de procesado, basadas en distintos modelos de computación: programada (con 2 fases: manual y computacional) y neuronal (mediante mapas autoorganizados de Kohonen, SOM), respectivamente. Este sistema ha sido optimizado usando, como cuerpo de datos, ham de “Enron Email” y spam de dos fuentes diferentes. Se analiza la calidad y el rendimiento del mismo mediante diferentes métricas.
Resumo:
Máster Universitario International en Acuicultura. Trabajo presentado como requisito parcial para la obtención del Título de Máster Universitario Internacional en Acuicultura, otorgado por la Universidad de Las Palmas de Gran Canaria (ULPGC), el Instituto Canario de Ciencias Marinas (ICCM), y el Centro Internacional de Altos Estudios Agronómicos Mediterráneos de Zaragoza (CIHEAM)
Resumo:
[EN] Background: Culicoides (Diptera: Ceratopogonidae) biting midges are vectors for a diversity of pathogens including bluetongue virus (BTV) that generate important economic losses. BTV has expanded its range in recent decades, probably due to the expansion of its main vector and the presence of other autochthonous competent vectors. Although the Canary Islands are still free of bluetongue disease (BTD), Spain and Europe have had to face up to a spread of bluetongue with disastrous consequences. Therefore, it is essential to identify the distribution of biting midges and understand their feeding patterns in areas susceptible to BTD. To that end, we captured biting midges on two farms in the Canary Islands (i) to identify the midge species in question and characterize their COI barcoding region and (ii) to ascertain the source of their bloodmeals using molecular tools.Methods: Biting midges were captured using CDC traps baited with a 4-W blacklight (UV) bulb on Gran Canaria and on Tenerife. Biting midges were quantified and identified according to their wing patterns. A 688 bp segment of the mitochondrial COI gene of 20 biting midges (11 from Gran Canaria and 9 from Tenerife) were PCR amplified using the primers LCO1490 and HCO2198. Moreover, after selected all available females showing any rest of blood in their abdomen, a nested-PCR approach was used to amplify a fragment of the COI gene from vertebrate DNA contained in bloodmeals. The origin of bloodmeals was identified by comparison with the nucleotide-nucleotide basic alignment search tool (BLAST). Results: The morphological identification of 491 female biting midges revealed the presence of a single morphospecies belonging to the Obsoletus group. When sequencing the barcoding region of the 20 females used to check genetic variability, we identified two haplotypes differing in a single base. Comparison analysis using the nucleotide-nucleotide basic alignment search tool (BLAST) showed that both haplotypes belong to Culicoides obsoletus, a potential BTV vector. As well, using molecular tools we identified the feeding sources of 136 biting midges and were able to confirm that C. obsoletus females feed on goats and sheep on both islands.Conclusions: These results confirm that the feeding pattern of C. obsoletus is a potentially important factor in BTV transmission to susceptible hosts in case of introduction into the archipelago. Consequently, in the Canary Islands it is essential to maintain vigilance of Culicoides-transmitted viruses such as BTV and the novel Schmallenberg virus.
Resumo:
[EN]Notwithstanding their scarcity and uneven distribution, zooarchaeological and stable isotope data sets on the Early and Middle Neolithic (5500–3200 cal BC) in the region of Estremadura in Central Portugal strongly suggest that two succeeding stages in subsistence strategies took place: sheep and goat itinerant pastoralism (across large areas) and/or renewed focus on wild food sources (cervid hunting, harvesting marine and freshwater food) which replaced livestock farming within smaller areas and less specialised hunting practices. This economic shift seems to have coincided with two other dramatic changes: the 5.9 kyr cal BP climate event and the onset of megalithism. Possible correlations between these past cultural and palaeoenvironmental phenomena are herein preliminarily outlined. [ES] A pesar de su escasez y distribución desigual, el conjunto de datos arqueozoológicos y de isótopos estables para el Neolítico Antiguo y Medio de la región de Estremadura en el centro de Portugal (5500-3200 a. C. cal), sugiere con claridad dos etapas sucesivas en las estrategias de subsistencia: pastoreo itinerante de ovejas y cabras (ocupando grandes territorios) y/o un renovado interés por los recursos alimenticios silvestres (caza de cérvidos, recolección de alimentos marinos y de agua dulce), que reemplazó otras formas de ganadería más confinadas en el espacio acciones con regímenes de mantenimiento reducidos y unas prácticas de caza menos especializadas. Este cambio económico parece haber ocurrido junto con otros dos cambios dramáticos, el evento climático 5.9 k BP (cal.) y el inicio del megalitismo. Aquí se esbozan de forma preliminar las posibles correlaciones entre estos fenómenos culturales y paleoambientales del pasado.