Aligning and synchronization of MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for DEEP core chronology

The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70���ka and how the results can be correlated with directly/indirectly radiometrically dated Mediterranean marine and continental proxy records. The alternative age model presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition.

(Table 1) Ostracode assemblage parameters in sediments of ODP Hole 113-689

During the late Paleocene thermal maximum (ca. 55.50 Ma) mid-bathyal ostracodes at Maud Rise in the Southern Ocean (Ocean Drilling Program Site 689) underwent a sudden, dramatic turnover synchronous with a global extinction in deep-sea benthic foraminifers and with large-scale, short-lived negative excursions in the stable isotope record of foraminiferal calcite. A previously stable and long-lived ostracode assemblage, dominated by heavily calcified, chiefly epifaunal taxa, was replaced within ~10 k.y. by a taxonomically novel association of small, thin-walled opportunistic and generalist forms that persisted for ~25-40 k.y. Thereafter, ostracode faunas recovered and common bathyal forms returned, although species were smaller and/or less-heavily calcified than before the turnover. The complex fabric of change in ostracode shell morphology and assemblage composition and structure reflects both long-term and sudden perturbations in seawater chemistry at this site. Ostracode data are in agreement with the hypothesis that the latest Paleocene extinctions in the deep sea were caused by a change in the dominant source area of intermediate water mass from high altitudes to the subtropics. These data also suggest that warm saline waters persisted at Maud Rise for the next 100 k.y.

Communication Middleware for Distributed Hard Real-Time Systems in Java

Distributed real-time embedded systems are becoming increasingly important to society. More demands will be made on them and greater reliance will be placed on the delivery of their services. A relevant subset of them is high-integrity or hard real-time systems, where failure can cause loss of life, environmental harm, or signi���cant ���nancial loss. Additionally, the evolution of communication networks and paradigms as well as the necessity of demanding processing power and fault tolerance, motivated the interconnection between electronic devices; many of the communications have the possibility of transferring data at a high speed. The concept of distributed systems emerged as systems where different parts are executed on several nodes that interact with each other via a communication network. Java���s popularity, facilities and platform independence have made it an interesting language for the real-time and embedded community. This was the motivation for the development of RTSJ (Real-Time Speci���cation for Java), which is a language extension intended to allow the development of real-time systems. The use of Java in the development of high-integrity systems requires strict development and testing techniques. However, RTJS includes a number of language features that are forbidden in such systems. In the context of the HIJA project, the HRTJ (Hard Real-Time Java) pro���le was developed to de���ne a robust subset of the language that is amenable to static analysis for high-integrity system certi���cation. Currently, a speci���cation under the Java community process (JSR- 302) is being developed. Its purpose is to de���ne those capabilities needed to create safety critical applications with Java technology called Safety Critical Java (SCJ). However, neither RTSJ nor its pro���les provide facilities to develop distributed realtime applications. This is an important issue, as most of the current and future systems will be distributed. The Distributed RTSJ (DRTSJ) Expert Group was created under the Java community process (JSR-50) in order to de���ne appropriate abstractions to overcome this problem. Currently there is no formal speci���cation. The aim of this thesis is to develop a communication middleware that is suitable for the development of distributed hard real-time systems in Java, based on the integration between the RMI (Remote Method Invocation) model and the HRTJ pro���le. It has been designed and implemented keeping in mind the main requirements such as the predictability and reliability in the timing behavior and the resource usage. iThe design starts with the de���nition of a computational model which identi���es among other things: the communication model, most appropriate underlying network protocols, the analysis model, and a subset of Java for hard real-time systems. In the design, the remote references are the basic means for building distributed applications which are associated with all non-functional parameters and resources needed to implement synchronous or asynchronous remote invocations with real-time attributes. The proposed middleware separates the resource allocation from the execution itself by de���ning two phases and a speci���c threading mechanism that guarantees a suitable timing behavior. It also includes mechanisms to monitor the functional and the timing behavior. It provides independence from network protocol de���ning a network interface and modules. The JRMP protocol was modi���ed to include two phases, non-functional parameters, and message size optimizations. Although serialization is one of the fundamental operations to ensure proper data transmission, current implementations are not suitable for hard real-time systems and there are no alternatives. This thesis proposes a predictable serialization that introduces a new compiler to generate optimized code according to the computational model. The proposed solution has the advantage of allowing us to schedule the communications and to adjust the memory usage at compilation time. In order to validate the design and the implementation a demanding validation process was carried out with emphasis in the functional behavior, the memory usage, the processor usage (the end-to-end response time and the response time in each functional block) and the network usage (real consumption according to the calculated consumption). The results obtained in an industrial application developed by Thales Avionics (a Flight Management System) and in exhaustive tests show that the design and the prototype are reliable for industrial applications with strict timing requirements. Los sistemas empotrados y distribuidos de tiempo real son cada vez m��s importantes para la sociedad. Su demanda aumenta y cada vez m��s dependemos de los servicios que proporcionan. Los sistemas de alta integridad constituyen un subconjunto de gran importancia. Se caracterizan por que un fallo en su funcionamiento puede causar p��rdida de vidas humanas, da��os en el medio ambiente o cuantiosas p��rdidas econ��micas. La necesidad de satisfacer requisitos temporales estrictos, hace m��s complejo su desarrollo. Mientras que los sistemas empotrados se sigan expandiendo en nuestra sociedad, es necesario garantizar un coste de desarrollo ajustado mediante el uso t��cnicas adecuadas en su dise��o, mantenimiento y certi���caci��n. En concreto, se requiere una tecnolog��a ���exible e independiente del hardware. La evoluci��n de las redes y paradigmas de comunicaci��n, as�� como la necesidad de mayor potencia de c��mputo y de tolerancia a fallos, ha motivado la interconexi��n de dispositivos electr��nicos. Los mecanismos de comunicaci��n permiten la transferencia de datos con alta velocidad de transmisi��n. En este contexto, el concepto de sistema distribuido ha emergido como sistemas donde sus componentes se ejecutan en varios nodos en paralelo y que interact��an entre ellos mediante redes de comunicaciones. Un concepto interesante son los sistemas de tiempo real neutrales respecto a la plataforma de ejecuci��n. Se caracterizan por la falta de conocimiento de esta plataforma durante su dise��o. Esta propiedad es relevante, por que conviene que se ejecuten en la mayor variedad de arquitecturas, tienen una vida media mayor de diez anos y el lugar �� donde se ejecutan puede variar. El lenguaje de programaci��n Java es una buena base para el desarrollo de este tipo de sistemas. Por este motivo se ha creado RTSJ (Real-Time Speci���cation for Java), que es una extensi��n del lenguaje para permitir el desarrollo de sistemas de tiempo real. Sin embargo, RTSJ no proporciona facilidades para el desarrollo de aplicaciones distribuidas de tiempo real. Es una limitaci��n importante dado que la mayor��a de los actuales y futuros sistemas ser��n distribuidos. El grupo DRTSJ (DistributedRTSJ) fue creado bajo el proceso de la comunidad de Java (JSR-50) con el ���n de de���nir las abstracciones que aborden dicha limitaci��n, pero en la actualidad aun no existe una especi���cacion formal. El objetivo de esta tesis es desarrollar un middleware de comunicaciones para el desarrollo de sistemas distribuidos de tiempo real en Java, basado en la integraci��n entre el modelo de RMI (Remote Method Invocation) y el per���l HRTJ. Ha sido dise��ado e implementado teniendo en cuenta los requisitos principales, como la predecibilidad y la con���abilidad del comportamiento temporal y el uso de recursos. El dise��o parte de la de���nici��n de un modelo computacional el cual identi���ca entre otras cosas: el modelo de comunicaciones, los protocolos de red subyacentes m��s adecuados, el modelo de an��lisis, y un subconjunto de Java para sistemas de tiempo real cr��tico. En el dise��o, las referencias remotas son el medio b��sico para construcci��n de aplicaciones distribuidas las cuales son asociadas a todos los par��metros no funcionales y los recursos necesarios para la ejecuci��n de invocaciones remotas s��ncronas o as��ncronas con atributos de tiempo real. El middleware propuesto separa la asignaci��n de recursos de la propia ejecuci��n de���niendo dos fases y un mecanismo de hebras especi���co que garantiza un comportamiento temporal adecuado. Adem��s se ha incluido mecanismos para supervisar el comportamiento funcional y temporal. Se ha buscado independencia del protocolo de red de���niendo una interfaz de red y m��dulos espec�����cos. Tambi��n se ha modi���cado el protocolo JRMP para incluir diferentes fases, par��metros no funcionales y optimizaciones de los tama��os de los mensajes. Aunque la serializaci��n es una de las operaciones fundamentales para asegurar la adecuada transmisi��n de datos, las actuales implementaciones no son adecuadas para sistemas cr��ticos y no hay alternativas. Este trabajo propone una serializaci��n predecible que ha implicado el desarrollo de un nuevo compilador para la generaci��n de c��digo optimizado acorde al modelo computacional. La soluci��n propuesta tiene la ventaja que en tiempo de compilaci��n nos permite plani���car las comunicaciones y ajustar el uso de memoria. Con el objetivo de validar el dise��o e implementaci��n se ha llevado a cabo un exigente proceso de validaci��n con ��nfasis en: el comportamiento funcional, el uso de memoria, el uso del procesador (tiempo de respuesta de extremo a extremo y en cada uno de los bloques funcionales) y el uso de la red (consumo real conforme al estimado). Los buenos resultados obtenidos en una aplicaci��n industrial desarrollada por Thales Avionics (un sistema de gesti��n de vuelo) y en las pruebas exhaustivas han demostrado que el dise��o y el prototipo son ���ables para aplicaciones industriales con estrictos requisitos temporales.

Communication-efficient and crash-quiescent Omega with unknown membership

The failure detector class Omega (��) provides an eventual leader election functionality, i.e., eventually all correct processes permanently trust the same correct process. An algorithm is communication-efficient if the number of links that carry messages forever is bounded by n, being n the number of processes in the system. It has been defined that an algorithm is crash-quiescent if it eventually stops sending messages to crashed processes. In this regard, it has been recently shown the impossibility of implementing �� crash quiescently without a majority of correct processes. We say that the membership is unknown if each process pi only knows its own identity and the number of processes in the system (that is, i and n), but pi does not know the identity of the rest of processes of the system. There is a type of link (denoted by ADD link) in which a bounded (but unknown) number of consecutive messages can be delayed or lost. In this work we present the first implementation (to our knowledge) of �� in partially synchronous systems with ADD links and with unknown membership. Furthermore, it is the first implementation of �� that combines two very interesting properties: communication-efficiency and crash-quiescence when the majority of processes are correct. Finally, we also obtain with the same algorithm a failure detector () such that every correct process eventually and permanently outputs the set of all correct processes.

Radiofrequency architectures and technologies for software defined radio

Six-port network is an interesting radiofrequency architecture with multiple possibilities. Since it was firstly introduced in the seventies as an alternative network analyzer, the six-port network has been used for many applications, such as homodyne receivers, radar systems, direction of arrival estimation, UWB (Ultra-Wide-Band), or MIMO (Multiple Input Multiple Output) systems. Currently, it is considered as a one of the best candidates to implement a Software Defined Radio (SDR). This thesis comprises an exhaustive study of this promising architecture, where its fundamentals and the state-of-the-art are also included. In addition, the design and development of a SDR 0.3-6 GHz six-port receiver prototype is presented in this thesis, which is implemented in conventional technology. The system is experimentally characterized and validated for RF signal demodulation with good performance. The analysis of the six-port architecture is complemented by a theoretical and experimental comparison with other radiofrequency architectures suitable for SDR. Some novel contributions are introduced in the present thesis. Such novelties are in the direction of the highly topical issues on six-port technique: development and optimization of real-time I-Q regeneration techniques for multiport networks; and search of new techniques and technologies to contribute to the miniaturization of the six-port architecture. In particular, the novel contributions of this thesis can be summarized as: - Introduction of a new real-time auto-calibration method for multiport receivers, particularly suitable for broadband designs and high data rate applications. - Introduction of a new direct baseband I-Q regeneration technique for five-port receivers. - Contribution to the miniaturization of six-port receivers by the use of the multilayer LTCC (Low Temperature Cofired Ceramic) technology. Implementation of a compact (30x30x1.25 mm) broadband (0.3-6 GHz) six-port receiver in LTTC technology. The results and conclusions derived from this thesis have been satisfactory, and quite fruitful in terms of publications. A total of fourteen works have been published, considering international journals and conferences, and national conferences. Aditionally, a paper has been submitted to an internationally recognized journal, which is currently under review.

High resolution system for nanoparticles hyperthermia efficiency evaluation

A system to evaluate nanoparticles efficiency in hyperthermia applications is presented. The method allows a direct measurement of the power dissipated by the nanoparticles through the determination of the first harmonic component of the in quadrature magnetic moment induced by the applied field. The magnetic moment is measured by using an induction method. To avoid errors and reduce the noise signal a double in phase demodulation technique is used. To test the system viability we have measured nanowires, nanoparticles and copper samples of different volumes to prove by comparing experimental and modeled results

Optimum Design of an Envelope Tracking Buck Converter for RF PA using GaN HEMTs

In this paper, filter design methodology and application of GaN HEMTs for high efficiency Envelope Amplifier in RF transmitters are proposed. The main objectives of the filter design are generation of the envelope reference with the minimum possible distortion and high efficiency of the amplifier obtained by the optimum trade-off between conduction and switching losses. This optimum point was determined using power losses model for synchronous buck with sinusoidal output voltage and experimental results showed good correspondence with the model and verified the proposed methodology. On the other hand, comparing to Si MOSFETs, GaN HEMTs can provide higher efficiency of the envelope amplifier, due to superior conductivity and switching characteristics. Experimental results verified benefits of GaN devices comparing to the appliance of Si switching devices with very good Figure Of Merit, for this particular application

Intelligent context-aware services based on internet of things architectures

La Internet de las Cosas (IoT), como parte de la Futura Internet, se ha convertido en la actualidad en uno de los principales temas de investigaci��n; en parte gracias a la atenci��n que la sociedad est�� poniendo en el desarrollo de determinado tipo de servicios (telemetr��a, generaci��n inteligente de energ��a, telesanidad, etc.) y por las recientes previsiones econ��micas que sit��an a algunos actores, como los operadores de telecomunicaciones (que se encuentran desesperadamente buscando nuevas oportunidades), al frente empujando algunas tecnolog��as interrelacionadas como las comunicaciones M��quina a M��quina (M2M). En este contexto, un importante n��mero de actividades de investigaci��n a nivel mundial se est��n realizando en distintas facetas: comunicaciones de redes de sensores, procesado de informaci��n, almacenamiento de grandes cantidades de datos (big--���data), sem��ntica, arquitecturas de servicio, etc. Todas ellas, de forma independiente, est��n llegando a un nivel de madurez que permiten vislumbrar la realizaci��n de la Internet de las Cosas m��s que como un sue��o, como una realidad tangible. Sin embargo, los servicios anteriormente mencionados no pueden esperar a desarrollarse hasta que las actividades de investigaci��n obtengan soluciones hol��sticas completas. Es importante proporcionar resultados intermedios que eviten soluciones verticales realizadas para desarrollos particulares. En este trabajo, nos hemos focalizado en la creaci��n de una plataforma de servicios que pretende facilitar, por una parte la integraci��n de redes de sensores y actuadores heterog��neas y geogr��ficamente distribuidas, y por otra lado el desarrollo de servicios horizontales utilizando dichas redes y la informaci��n que proporcionan. Este habilitador se utilizar�� para el desarrollo de servicios y para la experimentaci��n en la Internet de las Cosas. Previo a la definici��n de la plataforma, se ha realizado un importante estudio focalizando no s��lo trabajos y proyectos de investigaci��n, sino tambi��n actividades de estandarizaci��n. Los resultados se pueden resumir en las siguientes aseveraciones: a) Los modelos de datos definidos por el grupo ���Sensor Web Enablement��� (SWE���) del ���Open Geospatial Consortium (OGC��)��� representan hoy en d��a la soluci��n m��s completa para describir las redes de sensores y actuadores as�� como las observaciones. b) Las interfaces OGC, a pesar de las limitaciones que requieren cambios y extensiones, podr��an ser utilizadas como las bases para acceder a sensores y datos. c) Las redes de nueva generaci��n (NGN) ofrecen un buen sustrato que facilita la integraci��n de redes de sensores y el desarrollo de servicios. En consecuencia, una nueva plataforma de Servicios, llamada Ubiquitous Sensor Networks (USN), se ha definido en esta Tesis tratando de contribuir a rellenar los huecos previamente mencionados. Los puntos m��s destacados de la plataforma USN son: a) Desde un punto de vista arquitect��nico, sigue una aproximaci��n de dos niveles (Habilitador y Gateway) similar a otros habilitadores que utilizan las NGN (como el OMA Presence). b) Los modelos de datos est��n basado en los est��ndares del OGC SWE. iv c) Est�� integrado en las NGN pero puede ser utilizado sin ellas utilizando infraestructuras IP abiertas. d) Las principales funciones son: Descubrimiento de sensores, Almacenamiento de observaciones, Publicacion--���subscripcion--���notificaci��n, ejecuci��n remota homog��nea, seguridad, gesti��n de diccionarios de datos, facilidades de monitorizaci��n, utilidades de conversi��n de protocolos, interacciones s��ncronas y as��ncronas, soporte para el ���streaming��� y arbitrado b��sico de recursos. Para demostrar las funcionalidades que la Plataforma USN propuesta pueden ofrecer a los futuros escenarios de la Internet de las Cosas, se presentan resultados experimentales de tres pruebas de concepto (telemetr��a, ���Smart Places��� y monitorizaci��n medioambiental) reales a peque��a escala y un estudio sobre sem��ntica (sistema de informaci��n vehicular). Adem��s, se est�� utilizando actualmente como Habilitador para desarrollar tanto experimentaci��n como servicios reales en el proyecto Europeo SmartSantander (que aspira a integrar alrededor de 20.000 dispositivos IoT). v Abstract Internet of Things, as part of the Future Internet, has become one of the main research topics nowadays; in part thanks to the pressure the society is putting on the development of a particular kind of services (Smart metering, Smart Grids, eHealth, etc.), and by the recent business forecasts that situate some players, like Telecom Operators (which are desperately seeking for new opportunities), at the forefront pushing for some interrelated technologies like Machine--���to--���Machine (M2M) communications. Under this context, an important number of research activities are currently taking place worldwide at different levels: sensor network communications, information processing, big--��� data storage, semantics, service level architectures, etc. All of them, isolated, are arriving to a level of maturity that envision the achievement of Internet of Things (IoT) more than a dream, a tangible goal. However, the aforementioned services cannot wait to be developed until the holistic research actions bring complete solutions. It is important to come out with intermediate results that avoid vertical solutions tailored for particular deployments. In the present work, we focus on the creation of a Service--���level platform intended to facilitate, from one side the integration of heterogeneous and geographically disperse Sensors and Actuator Networks (SANs), and from the other the development of horizontal services using them and the information they provide. This enabler will be used for horizontal service development and for IoT experimentation. Prior to the definition of the platform, we have realized an important study targeting not just research works and projects, but also standardization topics. The results can be summarized in the following assertions: a) Open Geospatial Consortium (OGC��) Sensor Web Enablement (SWE���) data models today represent the most complete solution to describe SANs and observations. b) OGC interfaces, despite the limitations that require changes and extensions, could be used as the bases for accessing sensors and data. c) Next Generation Networks (NGN) offer a good substrate that facilitates the integration of SANs and the development of services. Consequently a new Service Layer platform, called Ubiquitous Sensor Networks (USN), has been defined in this Thesis trying to contribute to fill in the previous gaps. The main highlights of the proposed USN Platform are: a) From an architectural point of view, it follows a two--���layer approach (Enabler and Gateway) similar to other enablers that run on top of NGN (like the OMA Presence). b) Data models and interfaces are based on the OGC SWE standards. c) It is integrated in NGN but it can be used without it over open IP infrastructures. d) Main functions are: Sensor Discovery, Observation Storage, Publish--���Subscribe--���Notify, homogeneous remote execution, security, data dictionaries handling, monitoring facilities, authorization support, protocol conversion utilities, synchronous and asynchronous interactions, streaming support and basic resource arbitration. vi In order to demonstrate the functionalities that the proposed USN Platform can offer to future IoT scenarios, some experimental results have been addressed in three real--���life small--���scale proofs--���of concepts (Smart Metering, Smart Places and Environmental monitoring) and a study for semantics (in--���vehicle information system). Furthermore we also present the current use of the proposed USN Platform as an Enabler to develop experimentation and real services in the SmartSantander EU project (that aims at integrating around 20.000 IoT devices).

Historia holocena de los pinares montanos de los sistemas Central y Cant��brico: Un objetivo con dos enfoques, biogeogr��fico y dendroecol��gico

Los estudios paleoecol��gicos holocenos basados en macro- y megaf��siles encierran un gran valor debido a que su informaci��n tiene generalmente car��cter local, su origen es conocido, pueden ser datados directamente mediante el m��todo radiocarb��nico, y pueden identificarse a un nivel taxon��micamente preciso. Sin embargo son pocas las ��reas del Sur de Europa en las que sea conocida una alta densidad de yacimientos con restos le��osos de gran tama��o. En esta tesis, se presentan datos de 53 yacimientos de la sierra de Gredos y de la cordillera Cant��brica (Pen��nsula Ib��rica). Los restos fueron hallados en ambientes variados, como zonas higroturbosas, turberas erosionadas o lagos, y fueron identificadas mediante el estudio de la anatom��a de la madera o mediante rasgos morfol��gicos. En la sierra de Gredos, la evidencia paleobot��nica indica la existencia de un panorama relativamente estable a lo largo del Holoceno medio y principio del Holoceno final y sugiere la persistencia, a lo largo de milenios, de un piso de pinares ampliamente distribu��do en cotas altas de la sierra. La informaci��n obtenida de pi��as y frutos mejoran la informaci��n taxon��mica disponible y revelan la existencia tanto de Pinus sylvestris como de Pinus nigra en estas sierras durante el Holoceno. La dataci��n radiocarb��nica, medici��n de anillos de crecimiento y sincronizaci��n preliminar de 26 secciones de troncos de subf��siles demuestran el potencial de este material de las monta��as de Iberia central en la obtenci��n de cronolog��as holocenas de pino. En la cordillera Cant��brica, los datos aportan informaci��n espacialmente precisa de distribuciones de ciertas especies arb��reas durante el Holoceno. En las zonas centrales de la cordillera, han sido hallados fundamentalmente restos de pino, mientras que en las zonas m��s occidentales los pinos est��s ausentes y los restos encontrados corresponden a otras especies de caducifolios (Betula, Salix, Quercus) y arbustos (Erica, Fabaceae) Esta informaci��n paleobiogeogr��fica constrasta con la distribuci��n natural actual de Pinus sylvestris y Pinus nigra en el ��rea de estudio. En la sierra de Gredos, la naturalidad de las escasos rodales de pinos que a��n persisten ha sido discutida, mientras que en la cordillera Cant��brica, la ��nica especie del grupo que persiste es P. sylvestris y est�� localizada en unos pocos relictos. El clima pudo haber jugado un papel importante en una primera fase de declive de los pinares durante el Holoceno inicial, mostrado en numerosos registros pol��nicos de manera casi sincr��nica y asociada a una expansi��n de frondosas. Sin embargo la informaci��n hist��rica disponible y la comparaci��n entre las ��reas de distribuci��n de los pinares en el presente, modelizada y en momentos anteriores a la la generalizaci��n de la presi��n antr��pica sugiere que durante los ��ltimos dos milenios, la actividad humana ha sido responsable de la desaparici��n de estas especies como ��rboles naturales en ��reas extensas. ABSTRACTMacro- and megafossil studies provide information of great value in palaeoecology because such evidence is spatially precise, directly radiocarbon dated and usually taxon-specific. However, few areas of southern Europe have a high density of sites with Holocene woody remains. Here, local data from 53 sites in the Gredos Mountains and the Cantabrian Range (Iberian Peninsula) is presented. Woody remains were recovered from mires, eroded peat bogs and lakes and were identified by their wood anatomy or morphological traits. In the Gredos Mountains, palaeobotanical evidence portrays a relatively stable picture of tree distribution over the mid- and beggining of the late-Holocene, and suggests the persistence of a widespread belt of pinewoods. Cones and fruits enlarge the taxonomic information available and reveal that both Pinus sylvestris and Pinus nigra were present locally during the Holocene. Radiocarbon dating, tree ring measurement and preliminary cross-dating of 26 pine sub-fossil logs demonstrate the potential of obtaining a long pine chronology from subfossil wood from the mountains of Central Iberia. In the Cantabrian Range the data provide spatially precise evidence of tree distribution in the region during the Holocene. Pines were mostly identified in the central areas, whereas at the western edge no pine evidence was detected and deciduous trees (Betula, Salix, Quercus) and shrubs (Erica, Fabaceae) were identified. This palaeoecological information contrasts with the current natural distribution ranges of P. sylvestris and P. nigra in the study area. In the Gredos Mountains, the naturality of the few pine stands currently growing has been heavily debated. In the Cantabrian Range P. sylvestris is the only pine species that is today present, and its natural presence is now limited to a few enclaves. Climate may have played a key role in the early-Holocene, as pollen archives document a pine demise that is synchronous with the spread of broadleaved taxa. However, available historical data and the comparison of the reconstructed distribution of pinewoods before extensive human forest disturbance with both present and modelled distributions suggests that during the last two millennia, anthropogenic activity may have removed these species as native trees from a large territory.

Foundations of a New Interaction Paradigm for Immersive 3D Multimedia

Immersion and interaction have been identified as key factors influencing the quality of experience in stereoscopic video systems. The work presented here aims to create a new paradigm for 3D Multimedia consumption exploiting these factors in order to increase user involvement. We use a 5-sided CAVETM environment to support 3D panoramic video reproduction, real-time insertion of synthetic objects into the three-dimensional scene and real-time user interaction with the inserted elements. In this paper we describe our system requirements, functionalities, conceptual design and preliminary implementation results emphasizing the most relevant challenges accomplished. The focus is on three main issues: the generation of stereoscopic video panoramas; the synchronous reproduction of immersive 3D video across multiple screens; and, the real-time insertion algorithm implemented for the integration of synthetic objects into the stereoscopic video. These results have been successfully integrated into the graphic engine managing the operation of the CAVETM infrastructure.