Neighborhood mobility: A Long-Gone Pardigm? Approaching proximity and land use mix using data from home based surveys.

El WCTR es un congreso de reconocido prestigio internacional en el ámbito de la investigación del transporte y aunque las actas publicadas están en formato digital y sin ISSN ni ISBN, lo consideramos lo suficientemente importante como para que se considere en los indicadores. Policies trying to increase walking within urban mobility modal split usually highlight the importance of the functional patterns and the environmental quality of the urban space as major drivers of citizens modal choices. Functional characteristics would be mainly associated to an appropriate mix of land uses within neighbourhoods, whereas environmental quality would be associated to the characteristics of urban spaces. The purpose of this research is threefold: first, to identify relevant proxy indicators, which could characterize pedestrian-friendly land use mix and environmental quality. Second, to assess, for both traits, existing disparities among neighbourhoods in a major metropolitan area. And finally, to explore the association between both indicators and children mobility patterns: according to their built environment, which neighbourhoods have a greater proportion of children and, how is their mobility? Using data from the 2004 household mobility survey in the 128 neighbourhoods of the municipality of Madrid, this paper concludes that potentially favourable conditions at the neighbourhood level seem to have only a modest influence in,mobility patterns , in terms of both, selection of closer destinations and a higher share of walking within modal split. The citys policy choices, with intensive investment in road and public transport infrastructure may explain why short-distance mobility is not as important as it could have been expected in those neighbourhoods with more pedestrian-friendly conditions. The metropolitan transport system is providing mobility conditions, which make far-away destinations attractive to most citizens.

Neighbourhood mobility: a longgone Paradigm? Approaching "proximity" and "land use mix" using data from home-based surveys

Policies trying to increase walking within urban mobility modal split usually highlight the importance of the functional patterns and the environmental quality of the urban space as major drivers of citizens modal choices. Functional characteristics would be mainly associated to an appropriate mix of land uses within neighbourhoods, whereas environmental quality would be associated to the characteristics of urban spaces. The purpose of this research is threefold: first, to identify relevant proxy indicators, which could characterize pedestrian-friendly land use mix and environmental quality. Second, to assess, for both traits, existing disparities among neighbourhoods in a major metropolitan area. And finally, to explore the association between both indicators and children mobility patterns: according to their built environment, which neighbourhoods have a greater proportion of children and, how is their mobility? Using data from the 2004 household mobility survey in the 128 neighbourhoods of the municipality of Madrid, this paper concludes that potentially favourable conditions at the neighbourhood level seem to have only a modest influence in,mobility patterns , in terms of both, selection of closer destinations and a higher share of walking within modal split. The city s policy choices, with intensive investment in road and public transport infrastructure may explain why short-distance mobility is not as important as it could have been expected in those neighbourhoods with more pedestrian-friendly conditions. The metropolitan transport system is providing mobility conditions, which make far-away destinations attractive to most citizens.

Integración en la plataforma 4mobile de mecanismos de atención en redes sociales

El presente texto se ha desarrollado como Proyecto Fin de Grado en la Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación de la Universidad Politécnica de Madrid en colaboración con la Consultora Tecnológica everis. El mismo tiene como objetivo realizar un estudio de los requisitos necesarios para poder desplegar un servicio que permita ofrecer a las Operadoras Móviles Virtuales (OMV) soporte técnico a sus clientes a través de las redes sociales. Este módulo establecerá una nueva vía de comunicación entre el consumidor y el cliente de la OMV con la propia OMV, el cual se caracterizará por una alta accesibilidad y una gran rapidez en el servicio permitiendo de este modo, una mayor satisfacción del cliente con su operador móvil y por tanto de una nueva vía para conseguir la fidelización del mismo y la captación de nuevos clientes. Para ello, este proyecto se lleva a cabo sobre el sistema de información 4mobile el cual es comercializado por la mencionada Consultora Tecnológica. Este sistema consiste en una plataforma web la cual permite cubrir todos los procesos de negocio comunes que un OMV necesita gestionar. Es por ello, que el mencionado estudio se centra en la evaluación de los aspectos necesarios para la integración de un módulo de estas características dentro de la plataforma de 4mobile. Este módulo, estará basado en una herramienta software que permitirá gestionar el ciclo de vida completo del comentario realizado por el cliente a través de una red social, desde que es publicado por el cliente, hasta que se haya respondido al mismo y su solución sea considerada como satisfactoria por el cliente. Por ello, y de cara a definir correctamente esta herramienta, será necesario un detallado análisis el cual recoja diversos aspectos y que a lo largo del texto, será denominado como Plan de Marketing de Medios Sociales (PMMS). Estos aspectos versarán tanto de las necesidades tecnológicas para su mencionada integración, como de la serie de características funcionales que una solución basada en servicio técnico a través de las redes sociales deberá poseer con el objetivo de ofrecer un servicio técnico de calidad. Finalmente, estas funcionalidades y necesidades tecnológicas se expondrán en forma de propuesta a everis para su integración en la plataforma 4mobile junto con un análisis de diseño a alto nivel software de la solución a desarrollar. ABSTRACT. This text has been developed as Final Degree Project in the Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación de la Universidad Politécnica de Madrid in collaboration with the Technology Consultant everis, aims to conduct a study of how to provide technical support through social networks and the evaluation of the integration of a social support module within the system platform 4mobile, which cover all business processes that need to manage a Mobile Virtual Network Operator (MVNO), which is marketed by above-mentioned consultant . This module will establish a new communication channel between the consumer and the client with the OMV and itself, which is characterized by high accessibility and great fast service. Thus will allow a higher customer satisfaction with him service and thus a new way to get the same loyalty and attract new customers To this end, this project is performed on the information system 4mobile which is marketed by the consulting part thereof everis. This system is a platform to cover all business processes that need to manage an MVNO. Therefore, the mentioned study focuses on the evaluation of the elements necessary for integrating module these features within the platform 4mobile. This module will be based on a software tool for managing the entire lifecycle of the comment made by the customer via social networking, from the moment it is published, until it has been respond and their solution is considered satisfactory for the customer. So, in order to properly define this tool, a detailed analysis which will be necessary to collect various aspects and throughout the text, it will be referred to as Plan of Social Media Marketing (PMMS). These aspects will be address both: the technological needs for the mentioned integration, and the number of functional characteristics-based service through social networking solution, as this must in order to provide a quality service Finally, these goals and requirements will be discussed as everis offer for integration into the platform 4mobile analysis along with a high level of software design to develop the solution.

Optimization and evaluation in space conditions of multi-GHz optical modulators

Among the different optical modulator technologies available such as polymer, III-V semiconductors, Silicon, the well-known Lithium Niobate (LN) offers the best trade-off in terms of performances, ease of use, and power handling capability [1-9]. The LN technology is still widely deployed within the current high data rate fibre optic communications networks. This technology is also the most mature and guarantees the reliability which is required for space applications [9].In or der to fulfil the target specifications of opto-microwave payloads, an optimization of the design of a Mach-Zehnder (MZ) modulator working at the 1500nm telecom wavelength was performed in the frame of the ESA-ARTES "Multi GigaHertz Optical Modulator" (MGOM) project in order to reach ultra-low optical insertion loss and low effective driving voltage in the Ka band. The selected modulator configuration was the X-cut crystal orientation, associated to high stability Titanium in-diffusion process for the optical waveguide. Starting from an initial modulator configuration exhibiting 9 V drive voltage @ 30 GHz, a complete redesign of the coplanar microwave electrodes was carried out in order to reach a 6 V drive voltage @ 30GHz version. This redesign was associated to an optimization of the interaction between the optical waveguide and the electrodes. Following the optimisation steps, an evaluation program was applied on a lot of 8 identical modulators. A full characterisation was carried out to compare performances, showing small variations between the initial and final functional characteristics. In parallel, two similar modulators were submitted to both gamma (10-100 krad) and proton irradiation (10.109 p/cm²) with minor performance degradation.

Practical case with regard to applying the functional and environmental method to low crest level, detached breakwaters

The research work as presented in this article covers the design of detached breakwaters since they constitute a type of coastal defence work with which to combat many of the erosion problems found on beaches in a stable, sustainable fashion. The main aim of this work is to formulate a functional and environmental (but not structural) design method, enabling the fundamental characteristics of a detached breakwater to be defined as a function of the effect it is wished to induce on the coast, and taking into account variables of a different nature (climate, geomorphology and geometry) influencing the changes the shoreline undergoes after its construction. With this article, it is intended to submit the final result of the investigation undertaken, applying the detached breakwater design method as developed to solving a practical case. Thus it may be shown how the method enables a detached breakwater’s geometric pre-sizing to be tackled at a place on the coast with certain climate, geomorphology and littoral dynamic characteristics, first setting the final state of equilibrium it is wanted to obtain therein after its construction.

Functional and environmental design of detached, low crest level breakwaters

In this article we research the design of detached breakwaters, a type of coastal defence work designed to combat erosion on beaches in a stable, sustainable fashion. Our aim is to formulate a functional and environmental (nonstructural) method of design that defines the fundamental characteristics of a detached breakwater as a function of the desired effect on the coast whilst meeting social demands and preserving or improving the quality of the littoral environment. We aim to make this method generally applicable by considering relations between variables of different natures (climatic, geomorphologic, and geometric) influencing the changes experienced on the coast after the detached breakwater has been built. We carried out the study of the relations between the different variables on the data from 19 actual, existing detached breakwaters on the Spanish Mediterranean coastline, and we followed a methodology based on the implementation of nondimensional monomials and on a search for relations of dependency between them. Finally, we discussed the results obtained and came up with a proposal for a design method that uses some of the graphic relations found between the variables studied and that achieves the main objective. For example, a case of a detached breakwater’s geometric presizing is solved as a practical demonstration of how the method is applied. La investigación que se presenta en este artículo aborda el diseño de los diques exentos, por constituir estos un tipo de obras de defensa costera con el que poder luchar de una forma estable y sostenible contra muchos de los problemas de erosión que existen en las playas. El objetivo principal de este trabajo es la formulación de un método de diseño funcional y ambiental (no estructural) que permita definir las características fundamentales de un dique exento en función del efecto que se quiera inducir en la costa, satisfaciendo las demandas sociales y preservando o mejorando la calidad del medio ambiente litoral. Además, se busca la aplicabilidad general del método mediante la consideración de relaciones entre variables de distinta naturaleza (climáticas, geomorfológicas y geométricas) que tienen influencia en los cambios que se experimentan en la costa tras la construcción del dique exento. El estudio de las relaciones entre las distintas variables se realiza sobre los datos de una base de diecinueve diques exentos reales, existentes en el litoral mediterráneo español, y sigue una metodología basada en el planteamiento de monomios adimensionales y en la búsqueda de relaciones de dependencia entre ellos. Finalmente, la discusión de los resultados obtenidos conduce a la propuesta de un método de diseño que utiliza algunas de las relaciones graficas encontradas entre las variables estudiadas y con el que se consigue el objetivo principal anteriormente expuesto. Para demostrar la aplicación práctica del método se resuelve un caso de predimensionamiento geométrico de un dique exento a modo de ejemplo.

Adaptaciones cardiacas hemodinámicas, estructurales y funcionales a un programa de ejercicio físico supervisado durante el embarazo: ensayo clínico aleatorizado = Hemodynamic, structural and functional cardiac adaptations in a supervised physical exercise program during pregnancy: a randomized controlled trial

Introducción: Diversos cambios ocurren en el sistema cardiovascular materno durante el embarazo, lo que genera un gran estrés sobre este sistema especialmente durante el tercer trimestre, pudiendo acentuarse en presencia de determinados factores de riesgo. Los objetivos de este estudio fueron, valorar las adaptaciones cardiovasculares producidas por un programa específico de ejercicio físico; su seguridad sobre el sistema cardiovascular materno y los resultados del embarazo; y su eficacia en el control de los factores de riesgo cardiovascular. Material y métodos: El diseño del estudio fue un ensayo clínico aleatorizado. 151 gestantes sanas fueron evaluadas mediante un ecocardiograma y un electrocardiograma en la semana 20 y 34 de gestación. Un total de 89 gestantes participaron en un programa de ejercicio físico (GE) desde el primer hasta el tercer trimestre de embarazo, constituido principalmente por 25-30 minutos de trabajo aeróbico (55-60% de la frecuencia cardiaca de reserva), trabajo de fortalecimiento general y específico, y un trabajo de tonificación del suelo pélvico; desarrollado 3 días a la semana con una duración de 55-60 minutos cada sesión. Las gestantes aleatoriamente asignadas al grupo de control (GC; n=62) permanecieron sedentarias durante el embarazo. El estudio fue aprobado por el Comité Ético de investigación clínica del Hospital Universitario de Fuenlabrada. Resultados: Las características basales fueron similares entre ambos grupos. A diferencia del GC, las gestantes del GE evitaron el descenso significativo del gasto cardiaco indexado, entre el 2º y 3ºT de embarazo, y conservaron el patrón geométrico normal del ventrículo izquierdo; mientras que en el GC cambió hacia un patrón de remodelado concéntrico. En la semana 20, las gestantes del GE presentaron valores significativamente menores de frecuencia cardiaca (GC: 79,56±10,76 vs. GE: 76,05±9,34; p=0,04), tensión arterial sistólica (GC: 110,19±10,23 vs. GE: 106,04±12,06; p=0,03); tensión arterial diastólica (GC: 64,56±7,88 vs. GE: 61,81±7,15; p=0,03); tiempo de relajación isovolumétrica (GC: 72,94±14,71 vs. GE: 67,05±16,48; p=0,04); y un mayor tiempo de deceleración de la onda E (GC: 142,09±39,11 vs. GE: 162,10±48,59; p=0,01). En la semana 34, el GE presentó valores significativamente superiores de volumen sistólico (GC: 51,13±11,85 vs. GE: 56,21±12,79 p=0,04), de llenado temprano del ventrículo izquierdo (E) (GC: 78,38±14,07 vs. GE: 85,30±16,62; p=0,02) y de tiempo de deceleración de la onda E (GC: 130,35±37,11 vs. GE: 146,61±43,40; p=0,04). Conclusión: La práctica regular de ejercicio físico durante el embarazo puede producir adaptaciones positivas sobre el sistema cardiovascular materno durante el tercer trimestre de embarazo, además de ayudar en el control de sus factores de riesgo, sin alterar la salud materno-fetal. ABSTRACT Background: Several changes occur in the maternal cardiovascular system during pregnancy. These changes produce a considerable stress in this system, especially during the third trimester, which can be increased in presence of some risk factors. The aims of this study were, to assess the maternal cardiac adaptations in a specific exercise program; its safety on the maternal cardiovascular system and pregnancy outcomes; and its effectiveness in the control of cardiovascular risk factors. Material and methods: A randomized controlled trial was designed. 151 healthy pregnant women were assessed by an echocardiography and electrocardiography at 20 and 34 weeks of gestation. A total of 89 pregnant women participated in a physical exercise program (EG) from the first to the third trimester of pregnancy. It consisted of 25-30 minutes of aerobic conditioning (55-60% of their heart rate reserve), general and specific strength exercises, and a pelvic floor muscles training; 3 times per weeks during 55-60 minutes per session. Pregnant women randomized allocated to the control group (CG) remained sedentary during pregnancy. The study was approved by the Research Ethics Committee of Hospital Universitario de Fuenlabrada. Results: Baseline characteristics were similar between groups. Difference from the CG, pregnant women from the EG prevented the significant decrease of the cardiac output index, between the 2nd and 3rd trimester of pregnancy, and preserved the normal left ventricular pattern; whereas in the CG shifted to concentric remodeling pattern. At 20 weeks, women in the EG had significant lower heart rate (CG: 79,56±10,76 vs. EG: 76,05±9,34; p=0,04), systolic blood pressure (CG: 110,19±10,23 vs. EG: 106,04±12,06; p=0,03); diastolic blood pressure (CG: 64,56±7,88 vs. EG: 61,81±7,15; p=0,03); isovolumetric relaxation time (GC: 72,94±14,71 vs. GE: 67,05±16,48; p=0,04); and a higher deceleration time of E Wave (GC: 142,09±39,11 vs. GE: 162,10±48,59; p=0,01). At 34 weeks, the EG had a significant higher stroke volume (CG: 51,13±11,85 vs. EG: 56,21±12,79 p=0,04), early filling of left ventricular (E) (CG: 78,38±14,07 vs. EG: 85,30±16,62; p=0,02) and deceleration time of E wave (CG: 130,35±37,11 vs. EG:146,61±43,40; p=0,04). Conclusion: Physical regular exercise program during pregnancy may produce positive maternal cardiovascular adaptations during the third trimester of pregnancy. In addition, it helps to control the cardiovascular risk factors without altering maternal and fetus health.

Energy Management and Optimization for Video Decoders based on Functional-oriented Reconfiguration

In recent years, the increasing sophistication of embedded multimedia systems and wireless communication technologies has promoted a widespread utilization of video streaming applications. It has been reported in 2013 that youngsters, aged between 13 and 24, spend around 16.7 hours a week watching online video through social media, business websites, and video streaming sites. Video applications have already been blended into people daily life. Traditionally, video streaming research has focused on performance improvement, namely throughput increase and response time reduction. However, most mobile devices are battery-powered, a technology that grows at a much slower pace than either multimedia or hardware developments. Since battery developments cannot satisfy expanding power demand of mobile devices, research interests on video applications technology has attracted more attention to achieve energy-efficient designs. How to efficiently use the limited battery energy budget becomes a major research challenge. In addition, next generation video standards impel to diversification and personalization. Therefore, it is desirable to have mechanisms to implement energy optimizations with greater flexibility and scalability. In this context, the main goal of this dissertation is to find an energy management and optimization mechanism to reduce the energy consumption of video decoders based on the idea of functional-oriented reconfiguration. System battery life is prolonged as the result of a trade-off between energy consumption and video quality. Functional-oriented reconfiguration takes advantage of the similarities among standards to build video decoders reconnecting existing functional units. If a feedback channel from the decoder to the encoder is available, the former can signal the latter changes in either the encoding parameters or the encoding algorithms for energy-saving adaption. The proposed energy optimization and management mechanism is carried out at the decoder end. This mechanism consists of an energy-aware manager, implemented as an additional block of the reconfiguration engine, an energy estimator, integrated into the decoder, and, if available, a feedback channel connected to the encoder end. The energy-aware manager checks the battery level, selects the new decoder description and signals to build a new decoder to the reconfiguration engine. It is worth noting that the analysis of the energy consumption is fundamental for the success of the energy management and optimization mechanism. In this thesis, an energy estimation method driven by platform event monitoring is proposed. In addition, an event filter is suggested to automate the selection of the most appropriate events that affect the energy consumption. At last, a detailed study on the influence of the training data on the model accuracy is presented. The modeling methodology of the energy estimator has been evaluated on different underlying platforms, single-core and multi-core, with different characteristics of workload. All the results show a good accuracy and low on-line computation overhead. The required modifications on the reconfiguration engine to implement the energy-aware manager have been assessed under different scenarios. The results indicate a possibility to lengthen the battery lifetime of the system in two different use-cases.

Objective metrics for functional evaluation of upper limb during the ADL of drinking: application in SCI

Three-dimensional kinematic analysis provides quantitative assessment of upper limb motion and is used as an outcome measure to evaluate movement disorders. The aim of the present study is to present a set of kinematic metrics for quantifying characteristics of movement performance and the functional status of the subject during the execution of the activity of daily living (ADL) of drinking from a glass. Then, the objective is to apply these metrics in healthy people and a population with cervical spinal cord injury (SCI), and to analyze the metrics ability to discriminate between healthy and pathologic people. 19 people participated in the study: 7 subjects with metameric level C6 tetraplegia, 4 subjects with metameric level C7 tetraplegia and 8 healthy subjects. The movement was recorded with a photogrammetry system. The ADL of drinking was divided into a series of clearly identifiable phases to facilitate analysis. Metrics describing the time of the reaching phase, the range of motion of the joints analyzed, and characteristics of movement performance such as the efficiency, accuracy and smoothness of the distal segment and inter-joint coordination were obtained. The performance of the drinking task was more variable in people with SCI compared to the control group in relation to the metrics measured. Reaching time was longer in SCI groups. The proposed metrics showed capability to discriminate between healthy and pathologic people. Relative deficits in efficiency were larger in SCI people than in controls. These metrics can provide useful information in a clinical setting about the quality of the movement performed by healthy and SCI people during functional activities.

Cycling Dof Factors: Molecular and functional characterization of Arabidopsis thaliana AtCDF3 and tomato (Solanum lycopersicum L.) SlCDF3 in response to abiotic stress

El tomate (Solanum lycopersicum L.) es considerado uno de los cultivos hortícolas de mayor importancia económica en el territorio Español. Sin embargo, su producción está seriamente afectada por condiciones ambientales adversas como, salinidad, sequía y temperaturas extremas. Para resolver los problemas que se presentan en condiciones de estrés, se han empleado una serie de técnicas culturales que disminuyen sus efectos negativos, siendo de gran interés el desarrollo de variedades tolerantes. En este sentido la obtención y análisis de plantas transgénicas, ha supuesto un avance tecnológico, que ha facilitado el estudio y la evaluación de genes seleccionados en relación con la tolerancia al estrés. Estudios recientes han mostrado que el uso de genes reguladores como factores de transcripción (FTs) es una gran herramienta para obtener nuevas variedades de tomate con mayor tolerancia a estreses abióticos. Las proteínas DOF (DNA binding with One Finger) son una familia de FTs específica de plantas (Yangisawa, 2002), que están involucrados en procesos fisiológicos exclusivos de plantas como: asimilación del nitrógeno y fijación del carbono fotosintético, germinación de semilla, metabolismo secundario y respuesta al fotoperiodo pero su preciso rol en la tolerancia a estrés abiótico se desconoce en gran parte. El trabajo descrito en esta tesis tiene como objetivo estudiar genes reguladores tipo DOF para incrementar la tolerancia a estrés abiotico tanto en especies modelo como en tomate. En el primer capítulo de esta tesis se muestra la caracterización funcional del gen CDF3 de Arabidopsis, así como su papel en la respuesta a estrés abiótico y otros procesos del desarrollo. La expresión del gen AtCDF3 es altamente inducido por sequía, temperaturas extremas, salinidad y tratamientos con ácido abscísico (ABA). La línea de inserción T-DNA cdf3-1 es más sensible al estrés por sequía y bajas temperaturas, mientras que líneas transgénicas de Arabidopsis 35S::AtCDF3 aumentan la tolerancia al estrés por sequía, osmótico y bajas temperaturas en comparación con plantas wild-type (WT). Además, estas plantas presentan un incremento en la tasa fotosintética y apertura estomática. El gen AtCDF3 se localiza en el núcleo y que muestran una unión específica al ADN con diferente afinidad a secuencias diana y presentan diversas capacidades de activación transcripcional en ensayos de protoplastos de Arabidopsis. El dominio C-terminal de AtCDF3 es esencial para esta localización y su capacidad activación, la delección de este dominio reduce la tolerancia a sequía en plantas transgénicas 35S::AtCDF3. Análisis por microarray revelan que el AtCDF3 regula un set de genes involucrados en el metabolismo del carbono y nitrógeno. Nuestros resultados demuestran que el gen AtCDF3 juega un doble papel en la regulación de la respuesta a estrés por sequía y bajas temperaturas y en el control del tiempo de floración. En el segundo capítulo de este trabajo se lleva a cabo la identificación de 34 genes Dof en tomate que se pueden clasificar en base a homología de secuencia en cuatro grupos A-D, similares a los descritos en Arabidopsis. Dentro del grupo D se han identificado cinco genes DOF que presentan características similares a los Cycling Dof Factors (CDFs) de Arabidopsis. Estos genes son considerados ortólogos de Arabidopsis CDF1-5, y han sido nombrados como Solanum lycopersicum CDFs o SlCDFs. Los SlCDF1-5 son proteínas nucleares que muestran una unión específica al ADN con diferente afinidad a secuencias diana y presentan diversas capacidades de activación transcripcional in vivo. Análisis de expresión de los genes SlCDF1-5 muestran diferentes patrones de expresión durante el día y son inducidos de forma diferente en respuesta a estrés osmótico, salino, y de altas y bajas temperaturas. Plantas de Arabidopsis que sobre-expresan SlCDF1 y SlCDF3 muestran un incremento de la tolerancia a la sequía y salinidad. Además, de la expresión de varios genes de respuesta estrés como AtCOR15, AtRD29A y AtERD10, son expresados de forma diferente en estas líneas. La sobre-expresión de SlCDF3 en Arabidopsis promueve un retardo en el tiempo de floración a través de la modulación de la expresión de genes que controlan la floración como CONSTANS (CO) y FLOWERING LOCUS T (FT). En general, nuestros datos demuestran que los SlCDFs están asociados a funciones aun no descritas, relacionadas con la tolerancia a estrés abiótico y el control del tiempo de floración a través de la regulación de genes específicos y a un aumento de metabolitos particulares. ABSTRACT Tomato (Solanum lycopersicum L.) is one of the horticultural crops of major economic importance in the Spanish territory. However, its production is being affected by adverse environmental conditions such as salinity, drought and extreme temperatures. To resolve the problems triggered by stress conditions, a number of agricultural techniques that reduce the negative effects of stress are being frequently applied. However, the development of stress tolerant varieties is of a great interest. In this direction, the technological progress in obtaining and analysis of transgenic plants facilitated the study and evaluation of selected genes in relation to stress tolerance. Recent studies have shown that a use of regulatory genes such as transcription factors (TFs) is a great tool to obtain new tomato varieties with greater tolerance to abiotic stresses. The DOF (DNA binding with One Finger) proteins form a family of plant-specific TFs (Yangisawa, 2002) that are involved in the regulation of particular plant processes such as nitrogen assimilation, photosynthetic carbon fixation, seed germination, secondary metabolism and flowering time bur their precise roles in abiotic stress tolerance are largely unknown. The work described in this thesis aims at the study of the DOF type regulatory genes to increase tolerance to abiotic stress in both model species and the tomato. In the first chapter of this thesis, we present molecular characterization of the Arabidopsis CDF3 gene as well as its role in the response to abiotic stress and in other developmental processes. AtCDF3 is highly induced by drought, extreme temperatures, salt and abscisic acid (ABA) treatments. The cdf3-1 T-DNA insertion mutant was more sensitive to drought and low temperature stresses, whereas the AtCDF3 overexpression enhanced the tolerance of transgenic plants to drought, cold and osmotic stress comparing to the wild-type (WT) plants. In addition, these plants exhibit increased photosynthesis rates and stomatal aperture. AtCDF3 is localized in the nuclear region, displays specific binding to the canonical DNA target sequences and has a transcriptional activation activity in Arabidopsis protoplast assays. In addition, the C-terminal domain of AtCDF3 is essential for its localization and activation capabilities and the deletion of this domain significantly reduces the tolerance to drought in transgenic 35S::AtCDF3 overexpressing plants. Microarray analysis revealed that AtCDF3 regulated a set of genes involved in nitrogen and carbon metabolism. Our results demonstrate that AtCDF3 plays dual roles in regulating plant responses to drought and low temperature stress and in control of flowering time in vegetative tissues. In the second chapter this work, we carried out to identification of 34 tomato DOF genes that were classified by sequence similarity into four groups A-D, similar to the situation in Arabidopsis. In the D group we have identified five DOF genes that show similar characteristics to the Cycling Dof Factors (CDFs) of Arabidopsis. These genes were considered orthologous to the Arabidopsis CDF1 - 5 and were named Solanum lycopersicum CDFs or SlCDFs. SlCDF1-5 are nuclear proteins that display specific binding to canonical DNA target sequences and have transcriptional activation capacities in vivo. Expression analysis of SlCDF1-5 genes showed distinct diurnal expression patterns and were differentially induced in response to osmotic, salt and low and high temperature stresses. Arabidopsis plants overexpressing SlCDF1 and SlCDF3 showed increased drought and salt tolerance. In addition, various stress-responsive genes, such as AtCOR15, AtRD29A and AtERD10, were expressed differently in these lines. The overexpression of SlCDF3 in Arabidopsis also results in the late flowering phenotype through the modulation of the expression of flowering control genes such CONSTANS (CO) and FLOWERING LOCUS T (FT). Overall, our data connet SlCDFs to undescribed functions related to abiotic stress tolerance and flowering time through the regulation of specific target genes and an increase in particular metabolites.