123 research outputs found

    Unified charge transport in disordered organic field-effect transistors and light-emitting diodes

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    De ontdekking dat plastics zich als halfgeleiders kunnen gedragen heeft hun toepassingsgebied verruimd van speelgoed, tassen of meubilair naar elektronische producten zoals flexibele beeldschermen, radiofrequentie identificatie labels, fotocellen and chemische sensoren. In dit proefschrift bestuderen we de geleiding in wanorderlijke organische halfgeleiders. Deze materialen zijn bestudeerd onder de omstandigheden zoals ze in licht emitterende diodes (LEDs) en veldeffect transistoren (FETs) gebruikt worden. Een belangrijke parameter voor de beschrijving van de prestatie van deze applicaties is de mobiliteit van de ladingsdragers, hetgeen een maat is voor de snelheid waarmee de ladingsdragers door de polymeerfilm bewegen. Wij analyseren de mobiliteit van ladingsdragers als functie van temperatuur, elektrisch veld en ladingsdragerdichtheid. We laten zien dat een geunificeerd model voor zowel LEDs als FETs gebruikt kan worden, waarin de afhankelijkheid van de mobiliteit van de ladingsdragerdichtheid wordt meegenomen. Deze resultaten worden vervolgens gebruikt om de oorzaak van de sterke toename van de ruimteladingsbegrensde gatenstroom in poly(pphenylene vinylene) (PPV)-achtige polymeren bij hoge aangelegde spanningen te onderzoeken. We tonen aan dat de toename van de stroomdichtheid in ruimteladingsbegrensde diodes bij kamertemperatuur gedomineerd wordt door de dichtheidsafhankelijkheid van de gatenmobiliteit. Dit is in tegenspraak met de in de literatuur algemeen geaccepteerde aanname dat de bijdrage van het elektrische veld overheerst. Het ladingstransport van verschillende PPV derivaten zijn bestudeerd als functie van de chemische structuur en proces condities. Er wordt aangetoond dat d.m.v. chemische modificatie van asymmetrische naar volledig symmetrische gesubstitueerde PPVs de mobiliteit significant verbeterd kan worden. Een nieuw concept voor efficiente dubbellaag polymeren LEDs wordt gedemonstreerd. Een dergelijke LED bevat een polymeer met een hoge gatenmobiliteit, die de gaten efficient naar een sterk luminescerende laag transporteert.

    Programa de educación para la salud sobre la violencia de género dirigido al colectivo adolescente

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    Introducción: la violencia de género es un problema de salud pública que está presente en todas las culturas y países del mundo, indiferentemente del estatus social, nivel de estudios o religión. Actualmente, este tipo de violencia afecta cada vez más al colectivo adolescente, y las creencias erróneas sobre este tema constituyen un impedimento para su comprensión y suponen un factor de riesgo para su tolerancia. Las consecuencias negativas que acarrea sobre la salud de las víctimas una vez instaurada, hacen necesaria una actuación temprana con el fin de erradicar este problema. Objetivo principal: diseñar un programa de educación para la salud dirigido a adolescentes para la prevención de violencia de género en Zaragoza. Metodología: se ha realizado una búsqueda bibliográfica en diferentes fuentes de información: bases de datos y páginas web. Los artículos seleccionados han sido publicados entre 2008-2017. Conclusión: la repercusión de la violencia de género en la salud y en la calidad de vida de las mujeres que lo padecen, hace necesario, por parte del colectivo enfermero, una prevención primaria mediante la educación para la salud, con el fin de reducir este problema.<br /

    Renal Anomalies

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    This chapter is dedicated to the main renal anomalies detectable by ultrasound. Anomalies of the lower urinary tract will be addressed in a separate chapter. The anomalies presented are renal agenesis, renal development variants, autosomal recessive polycystic kidney disease, multicystic dysplastic kidney disease, autosomal dominant polycystic kidney disease, obstructive cystic dysplasia, pelvis dilatation, renal tumors, and nonchromosomal syndromes associated with renal anomalies. All chapters are structured similar into definition, incidence, pathology, ultrasound findings, differential diagnosis, and clinical facts

    Mortality and recruitment of fire-tolerant eucalypts as influenced by wildfire severity and recent prescribed fire

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    Mixed-species eucalypt forests of temperate Australia are assumed tolerant of most fire regimes based on the impressive capacity of the dominant eucalypts to resprout. However, empirical data to test this assumption are rare, limiting capacity to predict forest tolerance to emerging fire regimes including more frequent severe wildfires and extensive use of prescribed fire. We quantified tree mortality and regeneration in mixed-species eucalypt forests five years after an extensive wildfire that burnt under extreme fire weather. To examine combined site-level effects of wildfire and prescribed fire, our study included factorial replications of three wildfire severities, assessed as crown scorch and understorey consumption shortly after the wildfire (Unburnt, Low, High), and two times since last preceding fire (30 years since any fire). Our data indicate that while most trees survived low-severity wildfire through epicormic resprouting, this capacity was tested by high-severity wildfire. Five years after the wildfire, percentage mortalities of eucalypts in all size intervals from 10 to >70 cm diameter were significantly greater at High severity than Unburnt or Low severity sites, and included the near loss of the 10&#8211;20 cm cohort (93% mortality). Prolific seedling regeneration at High severity sites, and unreliable basal resprouting, indicated the importance of seedling recruitment to the resilience of these firetolerant forests. Recent prescribed fire had no clear effect on forest resistance (as tree survival) to wildfire, but decreased site-level resilience (as recruitment) by increasing mortalities of small stems. Our study indicates that high-severity wildfire has the potential to cause transitions to more open, simplified stand structures through increased tree mortality, including disproportionate losses in some size cohorts. Dependence on seedling recruitment could increase vulnerabilities to subsequent fires and future climates, potentially requiring direct management interventions to bolster forest resilience.Australian Governmen

    Remote sensing for the Spanish forests in the 21st century: a review of advances, needs, and opportunities

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    [EN] Forest ecosystems provide a host of services and societal benefits, including carbon storage, habitat for fauna, recreation, and provision of wood or non-wood products. In a context of complex demands on forest resources, identifying priorities for biodiversity and carbon budgets require accurate tools with sufficient temporal frequency. Moreover, understanding long term forest dynamics is necessary for sustainable planning and management. Remote sensing (RS) is a powerful means for analysis, synthesis and report, providing insights and contributing to inform decisions upon forest ecosystems. In this communication we review current applications of RS techniques in Spanish forests, examining possible trends, needs, and opportunities offered by RS in a forestry context. Currently, wall-to-wall optical and LiDAR data are extensively used for a wide range of applications—many times in combination—whilst radar or hyperspectral data are rarely used in the analysis of Spanish forests. Unmanned Aerial Vehicles (UAVs) carrying visible and infrared sensors are gaining ground in acquisition of data locally and at small scale, particularly for health assessments. Forest fire identification and characterization are prevalent applications at the landscape scale, whereas structural assessments are the most widespread analyses carried out at limited extents. Unparalleled opportunities are offered by the availability of diverse RS data like those provided by the European Copernicus programme and recent satellite LiDAR launches, processing capacity, and synergies with other ancillary sources to produce information of our forests. Overall, we live in times of unprecedented opportunities for monitoring forest ecosystems with a growing support from RS technologies.SIPart of this work was funded by the Spanish Ministry of Science, Innovation and University through the project AGL2016-76769-C2-1-R “Influence of natural disturbance regimes and management on forests dynamics, structure and carbon balance (FORESTCHANGE)”

    Remote sensing for the Spanish forests in the 21st century: a review of advances, needs, and opportunities

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    [EN] Forest ecosystems provide a host of services and societal benefits, including carbon storage, habitat for fauna, recreation, and provision of wood or non-wood products. In a context of complex demands on forest resources, identifying priorities for biodiversity and carbon budgets require accurate tools with sufficient temporal frequency. Moreover, understanding long term forest dynamics is necessary for sustainable planning and management. Remote sensing (RS) is a powerful means for analysis, synthesis, and report, providing insights and contributing to inform decisions upon forest ecosystems. In this communication we review current applications of RS techniques in Spanish forests, examining possible trends, needs, and opportunities offered by RS in a forestry context. Currently, wall-to-wall optical and LiDAR data are extensively used for a wide range of applications-many times in combination-whilst radar or hyperspectral data are rarely used in the analysis of Spanish forests. Unmanned Aerial Vehicles (UAVs) carrying visible and infrared sensors are gaining ground in acquisition of data locally and at small scale, particularly for health assessments. Forest fire identification and characterization are prevalent applications at the landscape scale, whereas structural assessments are the most widespread analyses carried out at limited extents. Unparalleled opportunities are offered by the availability of diverse RS data like those provided by the European Copernicus programme and recent satellite LiDAR launches, processing capacity, and synergies with other ancillary sources to produce information of our forests. Overall, we live in times of unprecedented opportunities for monitoring forest ecosystems with a growing support from RS technologies.Part of this work was funded by the Spanish Ministry of Science, innovation and University through the project AGL2016-76769-C2-1-R "Influence of natural disturbance regimes and management on forests dynamics. structure and carbon balance (FORESTCHANGE)".Gómez, C.; Alejandro, P.; Hermosilla, T.; Montes, F.; Pascual, C.; Ruiz Fernández, LÁ.; Álvarez-Taboada, F.... (2019). Remote sensing for the Spanish forests in the 21st century: a review of advances, needs, and opportunities. Forest Systems. 28(1):1-33. https://doi.org/10.5424/fs/2019281-14221S133281Ungar S, Pearlman J, Mendenhall J, Reuter D, 2003. Overview of the Earth Observing-1 (EO-1) mission. IEEE T Geosci Remote 41: 1149−1159.Valbuena R, Mauro F, Arjonilla FJ, Manzanera JA, 2011. Comparing Airborne Laser Scanning-Imagery Fusion Methods Based on Geometric Accuracy in Forested Areas. 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    Charge transport in disordered organic field-effect transistors

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