1000 resultados para error region
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This thesis deals with the oligochaete taxa (Annelida, Clitellata) from several karst units in the Cantabrian region, northern Iberian Peninsula. Groundwater oligochaetes are still poorly known fauna and the area seems to be a promising hotspot for groundwater taxa. Metodology is based on both morphological and molecular analyses. More than 7,000 specimens were collected from five karst units and >60 taxa were identified. Stygobiont oligochaete fauna in the northern Iberian Peninsula is diverse and mostly endemic (range areas <300 km). Three new stygogiont oligochaete species are described: Gianius navarroi Rodriguez & Achurra, 2010, Isochaetides gianii Rodriguez & Achurra, 2010 and Troglodrilus jugeti Achurra et al., 2012; and another four new taxa will be described in the near future. Taxonomic remarks on Lophochaeta ignota Stolc, 1886 and Troglodrilus galarzai (Giani & Rodriguez, 1988) are provided. The controversial separation of L. ignota and Heterochaeta costata Claparède, 1863 from Tubifex Lamarck, 1816 is corroborated by mitochondrial molecular data. Following the DNA barcoding method, individuals of the stygoxene species Stylodrilus heringianus Claparède, 1862 from different geographic areas are shown to represent a single metapopulation. The first phylogenetic analysis of the subfamily Tubificinae based on molecular data is attemped, which although incompletely resolved, evidences for the first time a close relationship between a stygobiont oligochaete (Troglodrilus Juget et al. 2006) and an estuarine especies (Heterochaeta costata Claparéde, 1863). A marine ancestor is hypothesised for Troglodrilus. Finally, Ereñozar karst unit (Biscay) is suggested to be a hotspot for groundwater oligochaetes (11 stygobiont taxa, of which 4 are endemic to the karst unit) and several biodiversity indices (Species richness, Rarity, Vulnerability and Complementarity) are shown to be useful tools for conservation management of groundwater habitats in that karst area.
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In the process of interferometric testing, the measurement result is influenced by the system structure, which reduces the measurement accuracy. To obtain an accurate test result, it is necessary to analyze the test system, and build the relationship between the measurement error and the system parameters. In this paper, the influences of the system elements which include the collimated lens and the standard surface on the interferometric testing are analyzed, the expressions of phase distribution and wavefront error on the detector are obtained, the method to remove some element errors is introduced, and the optimization structure relationships are given. (C) 2006 Elsevier GmbH. All rights reserved.
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Based on the generalized Huygens-Fresnel diffraction integral theory and the stationary-phase method, we analyze the influence on diffraction-free beam patterns of an elliptical manufacture error in an axicon. The numerical simulation is compared with the beam patterns photographed by using a CCD camera. Theoretical simulation and experimental results indicate that the intensity of the central spot decreases with increasing elliptical manufacture defect and propagation distance. Meanwhile, the bright rings around the central spot are gradually split into four or more symmetrical bright spots. The experimental results fit the theoretical simulation very well. (C) 2008 Society of Photo-Optical Instrumentation Engineers.
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El objeto del presente trabajo, titulado “Aplicación de redes neuronales artificiales para la caracterización del error en trayectorias circulares por WEDM”, es el estudio y posterior optimización del error en trayectorias circulares mecanizadas mediante electroerosión por hilo. Se pretende desarrollar un modelo predictivo de dicho error a través de la implementación de una Red Neuronal Artificial (RNA), que deberá ser alimentada con resultados empíricos resultantes de una batería de ensayos. El modelo desarrollado permitirá conocer a priori los errores que se producirán al cortar formas circulares en distintos espesores y con distintos radios sin necesidad de recurrir a costosas baterías de ensayos.
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A forma e o tamanho de um determinado organismo devem caracterizar aspectos ecológicos, uma vez que a morfometria é resultado da evolução. Diferenças nos caracteres morfológicos podem ter sido causadas por isolamento geográfico, mesmo em períodos de tempo relativamente curtos. O estudo da morfologia ecológica é uma tentativa de compreender a relação funcional entre variação morfológica e a ecologia dos animais. A variação nos atributos morfométricos de tamanho corpóreo entre os sexos pode ser um resultado da ação da seleção sexual. O presente estudo aborda uma comparação intrasexual e entre área continental e insular da morfologia de Conopophaga melanops (Vieillot, 1818), tendo sido realizado em uma área na Ilha Grande e em outra área na Reserva Ecológica Rio das Pedras (ReRP), RJ. A espécie, endêmica de Mata Atlântica e estritamente florestal, apresenta dimorfismo sexual, contudo indivíduos jovens possuem plumagem similar a de fêmeas. As aves foram capturadas com redes neblina, e doze medidas morfométricas foram obtidas de 51 indivíduos. A confirmação do sexo foi realizada por métodos moleculares baseados no DNA em 69 amostras. O percentual de erro na identificação do sexo em campo, pela plumagem, foi de 9,7%. A confirmação molecular do sexo é uma importante ferramenta que têm potencial de revelar padrões demográficos em estudos comportamentais e reprodutivos desta espécie. Na ReRP o comprimento da asa e a variável distância da cabeça até a ponta do bico apresentaram uma diferença significativa, sendo maior para machos do que para fêmeas. Já na Ilha Grande, as únicas variáveis que apresentaram diferença significativa foram comprimento da cauda (maior em machos) e altura do bico na base (maior em fêmeas). As diferenças de tamanho da asa entre os sexos corroboram com padrões de diversas outras espécies Neotropicais. A diferença morfométrica do bico pode estar associada à ecologia alimentar desta espécie. Tanto fêmeas quanto machos foram maiores na ilha do que no continente com relação ao comprimento total e comprimento da asa, além de comprimento da cauda maior para os machos.
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[EN] The objective of this paper is to analyze the incubation strategies developed in the universities of Andalusia, a relatively low-income region of Spain, to promote the creation of university spin-offs. These strategies are also compared to the incubation models noted in the literature. The performance of the university spin-offs created and its relation to the incubation strategies developed by the university are also analysed. The analysis is based on data from a survey of nine public universities that carry out strategies for the promotion of university spin-offs. The result of the analysis shows that university spin-off incubation strategies in Andalusia present specific characteristics not covered by certain models that are well-known in the literature on innovation. Then, a new stage in the process of the university spin-off incubation is proposed. We consider it to be a pre-strategic stage to the academic spin-off incubation strategies. The analysis also finds certain environmental factors associated to those spin-offs promoted by Andalusian universities that achieve the highest level of performance. This result suggests that previous to making any decision involving investment into developing incubation strategies, universities should gauge whether they have sufficient resources and the possibilities of connecting with a Technology Park.
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English: Data obtained from tagging experiments initiated during 1953-1958 and 1969-1981 for skipjack tuna from the coastal eastern Pacific Ocean (EPO) are reanalyzed, using the Schnute generalized growth model. The objective is to provide information that can be used to generate a growth transition matrix for use in a length-structured population dynamics model. The analysis includes statistical approaches to include individual variability in growth as a function of length at release and time at liberty, measurement error, and transcription error. The tagging data are divided into northern and southern regions, and the results suggest that growth rates differ between the two regions. The Schnute model provides a significantly better fit to the data than the von Bertalanffy model, a sub-model of the Schnute model, for the northern region, but not for the southern region. Individual variation in growth is best described as a function of time at liberty and as a function of growth increment for the northern and southern regions, respectively. Measurement error is a significant part of the total variation, but the results suggest that there is no bias caused by the measurement error. Additional information, particularly for small and large fish, is needed to produce an adequate growth transition matrix that can be used in a length-structured population dynamics model for skipjack tuna in the EPO. Spanish: Los datos obtenidos de los experimentos de marcado iniciados durante los períodos de 1953- 1958 y de 1969-1981 para el atún barrilete en las costas del Océano Pacífico Oriental (OPO) fueron analizados nuevamente, utilizando el modelo de crecimiento generalizado de Schnute. El objetivo es brindar información que sea útil para producir una matriz sobre la tran-sición de crecimiento que pueda utilizarse en un modelo de dinámica poblacional estructurado por talla. El análisis usa enfoques estadísticos para poder incluir la variabilidad individual del crecimiento como función de la talla de liberación y tiempo en libertad, el error de medición, y el error de transcripción. Los datos de marcado son divididos en regiones norte y sur, y los resultados sugieren que las tasas de crecimiento en las dos regiones son diferentes. En la región norte, pero no en la región sur, el modelo de Schnute se ajusta significativamente mejor a los datos que el modelo von Bertalanffy, un sub-modelo del modelo de Schnute. La mejor descripción de la variación individual en el crecimiento es como una función del tiempo en libertad y como una función del incremento de crecimiento para las regiones norte y sur, respectivamente. El error de medición es una parte significativa de la variación total, pero los resultados sugieren que no existe un sesgo causado por el error de medición. Se necesita información adicional, particularmente para peces pequeños y grandes, para poder producir una matriz de transición de crecimiento adecuada que pueda utilizarse en el modelo de dinámica poblacional estructurado por tallas para el atún barrilete en el OPO.
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[ES]En la actualidad el proceso de mecanizado mediante electroerosión por hilo (WEDM) posee varias problemáticas a la hora de la ejecución de los cortes para producir diferentes formas, ya sean esquinas, radios de redondeo o de acuerdo y por último la realización de círculos. Es por ello por lo que se elabora el presente trabajo cuya finalidad es llegar a caracterizar los errores cometidos en el corte de desbaste de probetas con trayectorias circulares y tecnología estándar. De esta manera se podrá cuantificar las desviaciones que se producen en las piezas en función del espesor y de sus radios. Toda la información obtenida en el trabajo permitirá una futura actuación en diversos parámetros máquina, elaborando nuevas tecnologías o bien poder mitigarlos realizando correcciones geométricas, ajustando sus tolerancias.
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Only the first- order Doppler frequency shift is considered in current laser dual- frequency interferometers; however; the second- order Doppler frequency shift should be considered when the measurement corner cube ( MCC) moves at high velocity or variable velocity because it can cause considerable error. The influence of the second- order Doppler frequency shift on interferometer error is studied in this paper, and a model of the second- order Doppler error is put forward. Moreover, the model has been simulated with both high velocity and variable velocity motion. The simulated results show that the second- order Doppler error is proportional to the velocity of the MCC when it moves with uniform motion and the measured displacement is certain. When the MCC moves with variable motion, the second- order Doppler error concerns not only velocity but also acceleration. When muzzle velocity is zero the second- order Doppler error caused by an acceleration of 0.6g can be up to 2.5 nm in 0.4 s, which is not negligible in nanometric measurement. Moreover, when the muzzle velocity is nonzero, the accelerated motion may result in a greater error and decelerated motion may result in a smaller error.