214 research outputs found

    Héðinsdalsjökull, northern Iceland: geomorphology recording the recent complex evolution of a glacier

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    The objective of this work is to conduct a detailed mapping of the Héðinsdalsjökull foreland, northern Iceland (65°39′N, 18°55′W). This cirque currently shows a variety of glacial and periglacial landforms derived from a complex deglaciation. Mapping was performed combining traditional hand-drawn and digital mapping. A hand-drawn sketch was georeferenced in ArcMap 10.7.1, supported on an aerial photograph (year 2000). Its vectorization, symbolization and final design were done in the computer-aided design (CAD) software MicroStation Connect. Complementary high-resolution Digital Surface Models were obtained from historical aerial photographs and ground-view field photographs through the application of Structure from Motion (SfM) photogrammetry. To improve the topographic expression of the geomorphological map, a photorealistic 3D view has been generated. The final map highlights the complexity of the foreland and the coexistence existence of a range of different units and landforms. The map will ease future studies on the transformation of receding glaciers.info:eu-repo/semantics/publishedVersio

    Semantically enabling UPnP Networks of Multimedia Home Content

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    There is plenty of multimedia content available in our homes, stored in multimedia disk drives, personal computers, or digital cameras. Protocols like Universal Plug and Play (UPnP) allow sharing this content among storage devices and displaying them in multimedia renderers in the local area networks of our homes. However, UPnP does not provide native support for the exchange of resources across homes neither does it provide means to describe multimedia content so as to facilitate search across multimedia resources. In this paper we describe a set of extensions to the UPnP protocol to provide a uniform access to multimedia content belonging to different homes, as well as mechanisms to create tag-based and ontology-based metadata, allowing search and Linked-Data publishing of these multimedia resources

    Técnicas de teledetección aplicadas al estudio de los ríos Tinto y Odiel

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    En este trabajo se presentan los resultados del tratamiento de imágenes Landsat TM y ATM Daedalus-1268 dirigido a la caracterización de la calidad del agua y al estudio de la hidrodinámica del estuario de los ríos Tinto y Odiel. La metodología aplicada se basa en la correlación de los parámetros físico-químicos y biológicos del agua con los valores radiométricos de las imágenes. El tratamiento de imágenes Landsat TM ha permitido estudiar la hidrodinámica del estuario, obteniendo la zonificación del mismo atendiendo a su homogeneidad temporal. Asimismo, se han aplicado técnicas de regresión múltiple y geoestadísticas (Cokrigeaje) para estimar la distribución espacial de parámetros de calidad. A partir del procesamiento de las imágenes ATM se ha obtenido una primera aproximación del contenido en clorofila, y de la distribución de temperaturas en el estuario.In this work we present the results of the Landsat TM and Daedalus image processing focus on the characterization of the water quality and on the study of the estuary hydrodynamic of the Tinto and Odiel rivers. The applied methodology is based on the correlation between parameters of water quality and the radiometric values of the images. The processing of a image set has allowed us to study the estuary hydrodynamic, obtaining the estuariny zones according to the degree of temporal homogeneity. Also, multiple regression and geostatistic techniques (Cokriging) has been applied to estimate the spatial distribution of quality water parameters. The ATM Daedalus image processing has enable us to obtain a first approximation of the chlorophyll and temperature distribution in the estuary

    9320 Bosques de Olea y Ceratonia

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    Dynamic bonding of metallic nanocontacts: Insights from experiments and atomistic simulations

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    The conductance across an atomically narrow metallic contact can be measured by using scanning tunneling microscopy. In certain situations, a jump in the conductance is observed right at the point of contact between the tip and the surface, which is known as “jump to contact” (JC). Such behavior provides a way to explore, at a fundamental level, how bonding between metallic atoms occurs dynamically. This phenomenon depends not only on the type of metal but also on the geometry of the two electrodes. For example, while some authors always find JC when approaching two atomically sharp tips of Cu, others find that a smooth transition occurs when approaching a Cu tip to an adatom on a flat surface of Cu. In an attempt to show that all these results are consistent, we make use of atomistic simulations; in particular, classical molecular dynamics together with density functional theory transport calculations to explore a number of possible scenarios. Simulations are performed for two different materials: Cu and Au in a [100] crystal orientation and at a temperature of 4.2 K. These simulations allow us to study the contribution of short- and long-range interactions to the process of bonding between metallic atoms, as well as to compare directly with experimental measurements of conductance, giving a plausible explanation for the different experimental observations. Moreover, we show a correlation between the cohesive energy of the metal, its Young's modulus, and the frequency of occurrence of a jump to contact.W. Dednam acknowledges support from the National Research Foundation of South Africa through the Scarce Skills Masters scholarship funding programme (Grant Unique Number 92138). This work is supported by the Generalitat Valenciana through Grant Reference PROMETEO2012/011 and MINECO under Grant No. FIS2013-47328, by European Union structural funds and the Comunidad de Madrid Programs S2013/MIT-3007 and P2013/MIT-2850. This work is also part of the research programme of the Foundation for Fundamental Research on Matter (FOM), which is financially supported by the Netherlands Organisation for Scientific Research (NWO)

    Reversible glacial-periglacial transition in response to climate changes and paraglacial dynamics: a case study from Héðinsdalsjökull (northern Iceland)

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    The objective of this work is to chronologically establish the origin of the different glacial and rock glacier complex landforms deposited by Héðinsdalsjökull glacier (65°39′ N, 18°55′ W), in the Héðinsdalur valley (Skagafjörður fjord, Tröllaskagi peninsula, central northern Iceland). Multiple methods were applied: geomorphological analysis and mapping, glacier reconstruction and equilibrium-line altitude calculation, Cosmic-Ray Exposure dating (in situ cosmogenic 36Cl), and lichenometric dating. The results reveal that a debris-free glacier receded around 6.6 ± 0.6 ka, during the Holocene Thermal Maximum. The retreat of the glacier exposed its headwall and accelerated paraglacial dynamics. As a result, the glacier terminus evolved into a debris-covered glacier and a rock glacier at a slightly higher elevation. The front of this rock glacier stabilized shortly after it formed, although nuclide inheritance is possible, but its sector close the valley head stabilized between 1.5 and 0.6 ka. The lowest part of the debris-covered glacier (between 600 and 820 m altitude) collapsed at ca. 2.4 ka. Since then, periods of glacial advance and retreat have alternated, particularly during the Little Ice Age. The maximum advance during this phase occurred in the 15th to 17th centuries with subsequent re-advances, namely at the beginning of the 19th and 20th centuries. After a significant retreat during the first decades of the 20th century, the glacier advanced in the 1960s to 1990s, and then retreated again, in accordance with the local climatic evolution. The internal ice of both the debris-covered and the rock glacier have survived until the present day, although enhanced subsidence provides evidence of their gradual degradation. A new rock glacier developed from an ice-cored moraine from around 1940–1950 CE. Thus, the Holocene coupling between paraglacial and climatic shifts has resulted in a complex evolution of Héðinsdalsjökull, which is conflicting with previously proposed models: a glacier, which had first evolved into a debris-covered and rock glacier, could later be transformed into a debris-free glacier, with a higher sensitivity to climatic variability.info:eu-repo/semantics/publishedVersio

    Implementation of multi-layer techniques using FEDERICA, PASITO and OneLab network infrastructures

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    Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. López, J. L. Añamuro, V. Moreno, J. E. L. De Vergara, J. Aracil, C. García, J. P. Fernández-Palacios, and M. Izal, "Implementation of multi-layer techniques using FEDERICA, PASITO and OneLab network infrastructures", in 17th IEEE International Conference on Networks, ICON 2011, p. 89-94This paper describes an implementation of multilayer techniques using the network infrastructure provided by FEDERICA, PASITO and OneLab projects. FEDERICA project provides a network infrastructure, based on virtualization capabilities in both network and computing resources, which creates custom-made virtual environments. PASITO is a layer- 2 network that connects universities and research centers in Spain. OneLab measurements tools allow carrying out highaccuracy active network measurements. Thanks to FEDERICA and PASITO, we have a multi-layer architecture where the traffic is routed based on the measurements of OneLab equipment. To carry out this experiment, we have developed a Multi-layer Traffic Engineering manager and an implementation of the Path Computation Element Protocol to solve the lack of a control plane in IP oriented networks. This work shows the feasibility of multilayer techniques as a convenient solution for network operators and it validates our Path Computation Element implementation.This work has been partially funded by the Spanish Ministry of Education and Science under project ANFORA (TEC2009-13385), by the Spanish Ministry of Industry, Tourism and Trade under PASITO project, and by the European Union under project OneLab2 (FP7-224263). Authors would like to thank Mauro Campanella (GARR, the project coordinator of FEDERICA) and Miguel Angel Sotos (RedIris) for their support to carry out this work

    Aproximación a la estima de la biomasa y producción primaria neta aéreas en una estación de la Laurisilva tinerfeña

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    Se realiza una primera aproximación a la estima de algunos parámetros tróficos en una estación de laurisilva en Tenerife. Los resultados son congruentes con los estimados para bosques similares en otras partes del mundo. La biomasa aérea se estimó a través de la técnica del análisis dimensional, mientras que la evaluación de la Producción Primaria Neta (pPN) se basó en el seguimiento de la caída de hojarasca durante un aIIO mediante bandej as. Se discute la validez de esta última técnica para determinar la PPN de los ecosistemas maduros.A first approach to the assesment of some trophics parameters of a laurel forest station in Tenerife is given. The results are congruent with those to be expected for similar forests of the world. The aereal biomass was calculated through the technique of dimensional analysis, while the evaluation ofNet Primary Production (NPP) was based in the study of the litter fall, using litter bags, during one year. The validity ofthis last technique to evaluate the NPP of mature ecosystems is discussed

    The origin and collapse of rock glaciers during the Bølling-Allerød interstadial: A new study case from the Cantabrian Mountains (Spain)

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    .During the Late Pleistocene, the main mountain ranges of the Iberian Peninsula were covered by small icefields and cirque and alpine glaciers. The deglaciation triggered paraglacial processes that generated landforms, mostly within the ice-free glacial cirques. In this research we analyse the deglaciation process in the Muxivén Cirque (42°15′N – 6°16′W), in the upper Sil River Basin, which includes some of the largest relict rock glaciers of the Cantabrian Mountains. We addressed this objective by means of accurate geomorphological reconstructions, sedimentological analysis, Schmidt-hammer surface weathering measurements and a dataset of 10 10Be Cosmic-Ray Exposure ages. Results reveal that after ~16 ka, glaciers retreated to the bottom of the cirques at the headwaters of the valley, leaving the walls free of ice and triggering rock avalanches onto the remnants of these glaciers. This paraglacial process supplied debris to a small glacier within Muxivén Cirque, which transformed in two rock glaciers. These debris isolated the ice inside the rock glaciers only for a very short period of time and ended up melting completely before the Younger Dryas. The lower sector of the largest one stabilized at 14.5 ± 1.5 ka, while the upper sector remained active until 13.5 ± 0.8 ka. Previous to the stabilization of the lower sector of the northern rock glacier, at its margin a high-energy debris avalanche occurred at ~14.0 ± 0.9 ka. These data agree with previous research, corroborating the paraglacial origin of most Iberian rock glaciers during the Bølling-Allerød interstadial.S

    Revista de Vertebrados de la Estación Biológica de Doñana

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    Captura de Petromyzon marinus lo en las Marismas del GuadalquivirEstudio sobre la Lagartiia de Valverde Algyroides marchi (Reptilia, Lacertidae)Dimorfismo sexual en Psammodromuus algirus (Reptilia, Lacertidae)Mecanismos de parasitización por Clamator glandarius y defensa por Pica pica.Nidificación de Cyanopica cyana en Doñana.Reproducción de la Urraca (P.pica) en DoñanaNesting relationship between Columba palambus and Milvus migransBiometría y dimorfismo sexual en el Calamón (Polphyrio porphyrio).Sobre sexo, mecanismos y proceso de reproducciónen el Buitre Leonado (Gyps fulvus)Aves anilladas por la Estación Biológica de Doñana. Informe Nº 1. (Años 1964 a 1971)Dimorfismo sexual y diferenciación de edades en Sturnus unicolor Temm.Contribución al estudio de la biología y ecología del Lirón Careto, Eliomys quercinus Linnaeus 1766, en Iberia Central, Parte 1: Crecimiento, Reproducción y Nidificación.Sobre el Lobo (Canis lupus) ibérico:1. Dimorfismo sexual en cráneosMorfología y dimorfismo sexual de la pelvis de Pitymys duodecimcostatusAlgunos aspectos del diformismo sexual en el cráneo de las Ginetas españolas, (Genetta genetta) (L.) 1758Peer reviewe
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