Diseño y aplicación de un sistema de medida polivalente para la realización de ensayos de dispersión electromagnética sobre materiales y recubrimientos

En las últimas décadas, el uso de campos electromagnéticos se ha generalizado en multitud de campos científicos y tecnológicos. Así, las plataformas aeronáuticas, tanto civiles como militares los vienen utilizando intensivamente o han sufrido su uso, siendo además pioneras en muchas de sus aplicaciones. En paralelo, los materiales y recubrimientos usados en las citadas plataformas están sufriendo una transformación constante para mejorar sus prestaciones. Por tanto, resultará imprescindible caracterizar el comportamiento de dichos materiales no sólo a nivel mecánico, térmico, etc. sino en relación a los citados campos electromagnéticos. De esta manera, el diseño e implementación de instalaciones y métodos de medida novedosos que mejoren esta caracterización resulta de gran utilidad. Y no sólo eso, sino que una concepción versátil que permita una gran variedad de ensayos en una misma instalación parece el camino a seguir en el escenario económico actual por el consiguiente ahorro de costes. En este ámbito tecnológico destaca sin duda el radar, que detectará todo objeto cuyo eco reflejado llegue a su receptor con una potencia superior a un umbral. Así, la reflectividad de un blanco viene caracterizada por su sección transversal radar o Radar Cross Section (RCS), por lo que su determinación, análisis y control resulta de gran interés, sobre todo en el ámbito militar. Y no sólo para configuración monoestática, ampliamente extendida en los sistemas radar operativos, sino también para configuración biestática, actualmente en auge entre la comunidad científica y militar por su capacidad para detectar los denominados blancos stealth. Por otro lado, un sistema capaz de caracterizar electromagnéticamente materiales de interés comparte muchas características con una instalación de medida de RCS, por lo que cobra todo el sentido diseñar un sistema versátil capaz de realizar no sólo ensayos de RCS, sino de medir la capacidad de un material para absorber la energía electromagnética, estimar su permitividad eléctrica y su permeabilidad magnética o comprobar el efecto de radomos y recubrimientos de antenas sobre su diagrama de radiación. Además, la misma instalación puede ser diseñada para permitir la implementación de medidas en campo cercano (y su posterior transformación a lejano) para antenas y, adicionalmente, la investigación de procedimientos para replicar este tipo de transformaciones en el ámbito de la RCS. Así, esta tesis gira en torno a una instalación de medida singular e innovadora denominada BIstatic ANechoic CHAmber (BIANCHA), concebida, diseñada y construida para posibilitar la realización de todos esos tipos de ensayos, que se incluyen en las líneas de investigación del Laboratorio de Detectabilidad y Guerra Electrónica del Instituto Nacional de Técnica Aeroespacial (INTA). Dicha instalación ha sido diseñada con un carácter versátil y polivalente, de modo que posibilita la realización sencilla de medidas mono y biestáticas tanto en reflexión como en transmisión, lo que permite implementar todos los tipos de ensayo enumerados. Entre las distintas aplicaciones, la tesis se centra en la investigación y desarrollo de nuevos métodos de medida de parámetros de radiación y dispersión aplicados a la determinación del comportamiento a nivel electromagnético de materiales y recubrimientos no metálicos avanzados usados en el ámbito aeronáutico, mostrándose no sólo la metodología seguida para cada caso concreto sino resultados de medida que demuestran la validez del diseño e implementación de la instalación

Reorganization of Northern Peri-Gondwanan Terranes at Cambrian–Ordovician Times: Insights from the Detrital Zircon Record of the Ossa-Morena Zone (SW Iberian Massif)

The Ossa-Morena Zone constitutes a fringe Gondwana-related terrane all along the Paleozoic. This continental block has been classically interpreted as being attached to a portion of the northern Gondwanan margin located close to the West African Craton. We report here the results of U-Pb dating on detrital zircon grains from 15 metasedimentary rocks collected in two well-exposed and well-dated Cambrian sections (Córdoba and Zafra) of the Ossa-Morena Zone. The studied samples show a dominant late Tonian-Ediacaran population peaked at c. 600 Ma. Secondary populations are Rhyacian-early Orosirian and late Orosirian-Statherian in age, with maxima at c. 2.1 and 1.9 Ga. Minor detrital zircon populations are Mesoarchean-early Siderian in age, with peaks between c. 3.05 and 2.45 Ga. Most of the studied samples lack a Stenian-early Tonian population, except for two of them with a minor peak at c. 1 Ga. Our results corroborate previous studies that locate the Ossa-Morena Zone close to the West African Craton and/or the Tuareg Shield (i.e., in a western position with respect to other Variscan zones of the Iberian Massif) at the onset of the rifting stage that opened the Rheic Ocean. Nevertheless, the absence of a significant Stenian-early Tonian population in the Cambrian Ossa-Morena rocks contrasts with the reported results on middle Ordovician-Lower Devonian rocks of this zone, which systematically contain an important population with a peak at c. 1 Ga. We relate this change to the latest Ediacaran-early Ordovician paleogeographic/paleotectonic evolution of the Ossa-Morena Zone, which might have recorded a significant eastward displacement, together with a reorganization of the drainage systems. Thus, the vanishing stages of the Cadomian orogeny could have translated eastward the Ossa-Morena Zone terrane at latest Ediacaran-earliest Cambrian time due to change in plate kinematics from subduction to right-lateral shearing. This translation would have shifted the Ossa-Morena Zone from an Ediacaran location close to the West African Craton to a Cambrian position close to the Tuareg Shield. Finally, the rift-to-drift transition occurred at late Cambrian-early Ordovician time along the northern Gondwanan margin would have reorganized the drainage systems, facilitating sediment supply from an eastern source with abundant Stenian-early Tonian detrital zircon grains, probably the Saharan Metacraton.Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades de la Junta de Andalucia P20_00063 PY20-01387Ministry of Science and Innovation, Spain (MICINN) Spanish Government PID2020-118822GB-I00 PID2020-119651RB-I0

The role of population change in the increased economic differences in mortality: a study of premature death from all causes and major groups of causes of death in Spain, 1980-2010

Background: An increase has been observed in differences in mortality between the richest and poorest areas of rich countries. This study assesses whether one of the proposed explanations, i.e., population change, might be responsible for this increase in Spain. Methods: Observational study based on average income, population change and mortality at provincial level. The premature mortality rate (ages 0-74 years) was estimated for all causes and for cancer, cardiovascular disease and external causes across the period 1980-2010. In the years analysed, provinces were grouped into tertiles based on provincial income, with the mortality rate ratio (MMR) being estimated by taking the tertile of highest-income provinces as reference. Population change was then controlled for to ascertain whether it would modify the rate ratio. Results: In all-cause mortality, the magnitude of the MRR for provinces in the poorest versus the richest tertile was 1.01 in 1980 and 1.12 in 2010; in cardiovascular mortality, the MMRs for these same years were 1.08 and 1.31 respectively; and in the case of cancer and external-cause mortality, MMR magnitude was similar in 1980 and 2010. The magnitude of the MMR remained unchanged in response to adjustment for population change, with the single exception of 1980, when it increased in all-cause and cardiovascular mortality. Conclusion: The increase in the difference in premature mortality between the richest and poorest areas in Spain is due to the increased difference in cardiovascular mortality. This increase is not accounted for by population change. In rich countries, more empirical evidence is thus needed to test other alternative explanations for the increase in economic differences in mortality.This study was conducted thanks to support from the Research Project PI12/01459 “Population change and geographical inequalities in mortality” financed by the Ministry of Science and Innovation

Seismic structure and composition of the southern central Iberian crust: The ALCUDIA wide angle seismic reflection transect

The authors thank the Associated Editor and the anonymous reviewers for their thoroughly valuable suggestions and comments that improved the manuscript. Seismic data were collected in 2012 with funding provided by the Spanish Ministry of Science and Innovation (grants: CGL2004-04623/BTE, CGL2007-63101/BTE, CGL2011-24101, CSD2006-00041). Instrumentation was provided by the IRIS-PASSCAL instrument center, Socorro, New Mexico, USA. The seismic data, including experiment geometry are stored in the IRIS-PASSCAL facilities and can be accessed through the IRIS-PASSCAL data management center. I.P. is funded by the Spanish Government and the Universidad de Salamanca with a Beatriz Galindo grant (BEGAL 18/00090). S.A. Ehsan is funded by the European Commission grant Marie Curie Actions (264517-TOPOMOD-FP7-PEOPLE-2010-ITN). We thank Instituto Geologico y Minero de Espana for providing the logistic help and an academic crew for data acquisition. GMT was used to prepare some of the figures shown in the paper.The nature of the crust beneath central Iberia was estimated by a wide-angle seismic reflection/refraction transect, ALCUDIA-WA, which sampled the southern half of the Variscan Central Iberian Zone, covered in the north by the Cenozoic Tajo Basin. The shot gathers recorded by vertical component sensors revealed well defined P- and S-wave phases. These arrivals were modeled by an iterative forward approach providing 2D crustal models showing variations in the velocity distribution with upper crustal P- and S-wave velocities increasing northwards. The lower crust P-wave velocities are homogeneous along the profile while the S-wave velocities slightly increase northwards. The Moho is placed at 32 km depth in the southern edge of the profile, deepening northward down to 35 km beneath the Tajo Basin. The Poisson's ratio, calculated from P- and S-wave velocities, varies along the profile at upper crustal depths. The highest values are located below the Mora and Pedroches batholiths. These resulting physical properties can serve to constrain the crustal composition by comparing them with laboratory measurements on rock samples. Our results suggest that the upper crust in the southern and central segments of the ALCUDIA profile is made up of low-grade metasedimentary rocks, while the northern segment is dominated by igneous rocks, in agreement with the surface geology. Separated by a sharp boundary located between 12 km (south) and 18 km (north) depth, the lower crust is more homogeneous and shows low Poisson’ ratios compatible with a rather felsic composition. However, outstanding lamination described in coincident vertical incidence data indicates some degree of intercalation with mafic components.Spanish Government CGL2004-04623/BTE CGL2007-63101/BTE CGL2011-24101 CSD2006-00041Spanish GovernmentEuropean Commission BEGAL 18/00090Universidad de Salamanca BEGAL 18/00090European Commission grant Marie Curie Actions 264517-TOPOMOD-FP7-PEOPLE-2010-IT

From the surface Topography to the Upper mantle beneath Central-Iberian-Zone. The ALCUDIA Seismic Experiments

American Geophysical Union, Fall Meeting 15-19 December, 2014, San FranciscoMulti-seismic experiments acquired across the central and southern part of the Iberian Peninsula provide a new insight into the structure and nature of the lithosphere beneath these areas. Normal incidence and wide-angle seismic reflection data acquired in the area resolve the internal architecture and constrain the distribution of the physical properties along an almost 280 km long transect that samples the major tectonic domains of the Central Iberian Zone (CIZ) and the associated suture (e.g., the Central Unit, CU). A high quality image, ~230 km long, down to 45 km depth (~15 s TWTT) is provided by the normal incidence data set. Based on the reflectivity characteristics, the image can be divided into an upper and mid-lower crust, ~13 km and ~18 km thick, respectively. The wide-angle seismic transect extended the crustal section towards the north across the Madrid Basin. This, latter data set also sample the CIZ until the CU. This is ~280 km long profile which provides very strong constraints on the distribution of physical properties (P wave and S wave velocities, Poisson's ratio) of the upper lithosphere. The PiP and PmP seismic phases constrain two discontinuities: the brittle to ductile discontinuity at ~13-19 km and the Moho boundary at ~31-35.5 km. Currently both appear to act as decoupling surfaces and are interpreted to represent levels of lithological/rheological variations. The internal structure of the Moho is further discussed taking into account the characteristics of the PmP reflections. Furthermore, low fold wide-angle P and S wave stacks reveal a marked crust-mantle transition which is most probably 5-6 km thick and relatively complex structure. The geometrical relationships of this structure with the crustal fabrics of the normal incidence image suggest that the Moho is most probably a result of the re-equilibration and/or other lithospheric processes active after the Variscan collision

The role of defoliation and root rot pathogen infection in driving the mode of drought-related physiological decline in Scots pine (Pinus sylvestris L.)

Drought-related tree die-off episodes have been observed in all vegetated continents. Despite much research effort, however, the multiple interactions between carbon starvation, hydraulic failure and biotic agents in driving tree mortality under field conditions are still not well understood. We analysed the seasonal variability of non-structural carbohydrates (NSCs) in four organs (leaves, branches, trunk and roots), the vulnerability to embolism in roots and branches, native embolism (percentage loss of hydraulic conductivity (PLC)) in branches and the presence of root rot pathogens in defoliated and non-defoliated individuals in a declining Scots pine (Pinus sylvestris L.) population in the NE Iberian Peninsula in 2012, which included a particularly dry and warm summer. No differences were observed between defoliated and non-defoliated pines in hydraulic parameters, except for a higher vulnerability to embolism at pressures below -2 MPa in roots of defoliated pines. No differences were found between defoliation classes in branch PLC. Total NSC (TNSC, soluble sugars plus starch) values decreased during drought, particularly in leaves. Defoliation reduced TNSC levels across tree organs, especially just before (June) and during (August) drought. Root rot infection by the fungal pathogen Onnia P. Karst spp. was detected but it did not appear to be associated to tree defoliation. However, Onnia infection was associated with reduced leaf-specific hydraulic conductivity and sapwood depth, and thus contributed to hydraulic impairment, especially in defoliated pines. Infection was also associated with virtually depleted root starch reserves during and after drought in defoliated pines. Moreover, defoliated and infected trees tended to show lower basal area increment. Overall, our results show the intertwined nature of physiological mechanisms leading to drought-induced mortality and the inherent difficulty of isolating their contribution under field conditions

Systematics of detrital zircon U–Pb ages from Cambrian–Lower Devonian rocks of northern Morocco with implications for the northern Gondwanan passive margin

This study was found by the Ministerio de Economia y Competitividad (MINECO) of Spain through the project PANGEATOR (CGL2015-71692) and the Pre-Doctoral scholarship BES-2016-078168. We are indebted to Mike Hall and Brad McDonald for their assistance and technical support on sample preparation and the LA-ICPMS, respectively. The CL imaging was carried out on the Curtin University's Microscopy & Microanalysis Facility, whose instrumentation has been partially funded by the University, State and Commonwealth Governments, and the Scanning Electron Microscope (SEM) Facility at the University of Edinburgh. Analysis in the SHRIMP and GeoHistory Facilities, JdLC, Curtin University were enabled by AuScope (auscope.org.au) and the Australian Government via the National Collaborative Research Infrastructure Strategy (NCRIS) and an Australian Geophysical Observing System grant provided to AuScope Pty Ltd. by the AQ44 Australian Education Investment Fund program, respectively. The NPII multi-collector was obtained via funding from the Australian Research Council LIEF program (LE150100013). The SIMS analyses were performed at the NERC Ion Microprobe Facility of the University of Edinburgh (UK). Comments from two anonymous reviewers and editorial handling by Prof. Victoria Pease are acknowledged. Funding for open access charge: YUniversidad de Granada / CBUA.The systematic acquisition of U–Pb geochronological data from detrital zircon grains has become an essential tool in tectonic studies focused on reconstructing the pre–Variscan geography of the northern Gondwanan passive margin. New detrital zircon ages for 16 samples from the Cambrian–Lower Devonian succession of the Moroccan Mesetas (northern Morocco) are reported here. The results, combined with previously published data, reassert the strong West African Craton affinity of the Paleozoic sedimentary rocks, characterized by dominant Cadomian/Pan–African (c. 850–540 Ma) and Eburnean (c. 2.2–1.9 Ga) detrital zircon populations and a minor Leonian/Liberian (c. 2.5 Ga) population. Primary sources of these zircon grains are well established as the West African Craton located just to the south, but also in the Precambrian basement that locally crops out in the Moroccan Mesetas themselves. During the Cambrian–Early Ordovician, erosion preferentially dismantled Cadomian (c. 590–540 Ma) arc–derived rocks of the Gondwanan continental margin, while later, the slightly older Pan–African (c. 650–600 Ma) basement became the main sediment source. In the studied samples, irregularly present minor detrital zircon populations suggest additional sediment provenance from secondary sources such as: (i) remote northeastern African cratons (e.g., Saharan Metacraton and/or Arabian–Nubian Shield) that likely could have provided the c. 1.1–0.9 Ga and, possibly, the c. 1.9–1.7 Ga zircon grains, and (ii) rift–related Cambrian–Early Ordovician volcanic centers in the Moroccan Mesetas that supplied heterogeneously distributed – although locally dominant in small areas – sedimentary detritus before rift abortion and burial underneath the overlying passive margin sedimentary succession.Ministerio de Economia y Competitividad (MINECO) of Spain through the project PANGEATOR CGL2015-71692Scanning Electron Microscope (SEM) Facility at the University of EdinburghAustralian Geophysical Observing System grant by AQ44 Australian Education Investment Fund programAustralian Research Council LE150100013Universidad de Granada / CBUA BES-2016-07816

Mixed and recycled detrital zircons in the Paleozoic rocks of the Eastern Moroccan Meseta: Paleogeographic inferences

Ministerio de Economía y Competividad (MINECO) of Spain through the project CGL2015-71692-P and the Pre-Doctoral scholarship BES-2016-078168. Zircon analyses and imaging were carried out on the SHRIMP II, LA-ICPMS and SEM facilities at the John de Laeter Centre, Curtin University, with the financial support of the Australian Research Council (LE150100013) and Auscope NCRIS (AQ44 Australian Education Investment Fund program)The paleogeographic evolution of the Moroccan Variscides has been a matter of discussion for several decades, with current theoriesmostly based on classical geological correlations. In this regard, the scarce number of studies devoted to U-Pb geochronological analyses of detrital zircon populations is particularly limiting when trying to ascribe the different domains to a single continental piece either derived from the West African Craton or to different sources, with some located in the Nubian Shield or the SaharanMetacraton. In thiswork, detrital zircon grains from 10 samples of sandstones from the Paleozoic (Ordovician to Devonian) sequence of the Eastern Meseta andMiddle Atlaswere dated in order to identify possible sediment sources and elucidate the paleogeography of this easternmost portion of the Moroccan Variscides. The main detrital zircon populations have Ediacaran-Cryogenian ages (610–670 Ma, related to the Cadomian and/or Pan-African orogeny) and middle Paleoproterozoic ages (1980–2080 Ma, related to the Eburnean orogeny), which are in agreement with previous data from the Western Meseta, suggesting similarity between both Mesetas, and strong West African Craton affinity. Such an affinity verifies themost accepted paleogeographic interpretation considering that theMoroccan Mesetas remained attached to northern Gondwana during the entire Paleozoic period. The main differences between our samples and those from the Western Meseta concern the minor detrital zircon populations, such as the Cambro-Ordovician and the Tonian-Stenian ones. In particular, Eastern Meseta and Middle Atlas samples lack a Cambro-Ordovician detrital zircon population, usually interpreted as related to the rifting that opened the Rheic Ocean. This population is locally reported in the Western Meseta and widely described in southwestern Europe, where magmatism of this age is well known. Furthermore, the most northeastern samples are also characterized by a Tonian-Stenian detrital zircon population (up to 30% of the data), which might imply northeastern African sources (Saharan Metacraton and/or Arabian-Nubian Shield)Ministerio de Economía y Competividad (MINECO) of Spain CGL2015-71692-P, BES-2016-078168Australian Research Council (LE150100013)Auscope NCRIS (AQ44 Australian Education Investment Fund program