127 research outputs found

    Drought as a possible contributor to the Visigothic Kingdom crisis and Islamic expansion in the Iberian Peninsula

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    The Muslim expansion in the Mediterranean basin was one the most relevant and rapid cultural changes in human history. This expansion reached the Iberian Peninsula with the replacement of the Visigothic Kingdom by the Muslim Umayyad Caliphate and the Muslim Emirate of Córdoba during the 8th century CE. In this study we made a compilation of western Mediterranean pollen records to gain insight about past climate conditions when this expansion took place. The pollen stack results, together with other paleohydrological records, archaeological data and historical sources, indicate that the statistically significant strongest droughts between the mid-5th and mid-10th centuries CE (450–950 CE) occurred at 545–570, 695–725, 755–770 and 900–935 CE, which could have contributed to the instability of the Visigothic and Muslim reigns in the Iberian Peninsula. Our study supports the great sensitivity of the agriculture-based economy and socio-political unrest of Early Medieval kingdoms to climatic variationsMinistry of Science and Innovation of the Government of Spain, Agencia Estatal de Investigación /10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional - A way ofmaking Europe, in particular the grant numbers FJC2020-044215- IThe grant number Retos P20_00059The action Proyectos I + D + i del Programa Operativo FEDER 2018 (grant number A-RNM-336-UGR20Research group RNM-190 from the Junta de Andalucía (Regional Government of Andalusia)The project SBPLY/21/ 180501/000205Scientific Research and Technology Transfer Projects of the Junta deComunidades de Castilla-La Mancha (Regional Government of Castilla-La Mancha

    Long-term performance of magnetic force microscopy tips grown by focused electron beam induced deposition

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    High-resolution micro- and nanostructures can be grown using Focused Electron Beam Induced Deposition (FEBID), a direct-write, resist-free nanolithography technology which allows additive patterning, typically with sub-100 nm lateral resolution, and down to 10 nm in optimal conditions. This technique has been used to grow magnetic tips for use in Magnetic Force Microscopy (MFM). Due to their high aspect ratio and good magnetic behavior, these FEBID magnetic tips provide several advantages over commercial magnetic tips when used for simultaneous topographical and magnetic measurements. Here, we report a study of the durability of these excellent candidates for high-resolution MFM measurements. A batch of FEBID-grown magnetic tips was subjected to a systematic analysis of MFM magnetic contrast for 30 weeks, using magnetic storage tape as a test specimen. Our results indicate that these FEBID magnetic tips operate effectively over a long period of time. The magnetic signal was well preserved, with a maximum reduction of 60% after 21 weeks of recurrent use. No significant contrast degradation was observed after 30 weeks in storage

    Laguna Seca sediments reveal environmental and climate change during the latest Pleistocene and Holocene in Sierra Nevada, southern Iberian Peninsula

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    This study was supported by the I + D + i projects CGL2013-47038- R, CGL2017-85415-R, PID2019-1049449GB-I00, and PID2021- 125619OB-C21/C22 funded by Ministerio Ciencia e Innovación/Agencia Estatal de Investigación/ 10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa”, I + D + i projects A-RNM-336-UGR20 and P20_00059 of the action “Proyectos I + D + i del Programa Operativo FEDER - Junta de Andalucía - UGR” and the research group RNM-190. This research is part of the project “Thematic Center on Mountain Ecosystem & Remote sensing, Deep learning- AI e-Services University of Granada-Sierra Nevada” (LifeWatch-2019- 10-UGR-01), which has been co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action line. José Carrión was supported by the I + D + I project PID2019-1049449 GB-I00 funded by MCIN/AEI/ 10.13039/501100011033/ and FEDER “Una manera de hacer Europa” and the fellowship 20788/PI/18 of Fundación Séneca. We thank Javier Jaimez for his help with the core drilling in Laguna Seca and Alejandro Navarro and Aurora Baquera for the sediment sampling. ALA acknowledges the predoctoral fellowship BES- 2018-084293 provide by the MCIN/ AEI/ 10.13039/5011000110 33/. CLB acknowledges the European Union for her Marie Sklodowska-Curie grant agreement number 892487 under Horizon 2020 funds. JC acknowledges the Ministerio de Ciencia e Innovación of the Spanish Government for the grant number FJC2020-044215-I of the Juan de la Cierva Formación postdoctoral program.Sedimentation in most glacial lakes and wetlands in the Sierra Nevada (southern Iberian Peninsula) began after the last deglaciation and since the Younger Dryas (YD)-Early Holocene (EH) transition. Therefore, until now, studies on older sedimentary records were lacking in this alpine area, which limits the paleoenvironmental and paleoclimatic information to the Holocene. In this study, we studied palynomorphs from the alpine record from Laguna Seca (LS), the longest and oldest (∼18,000 cal yr BP = 18 kyr) sedimentary record in the Sierra Nevada to investigate the response of forests and lake environments in the western Mediterranean area to climate changes and human impact during the latest Pleistocene and Holocene. The deepest lake conditions occurred during the last deglaciation, indicated by the occurrence of Pediastrum algae, which showed highest abundances during the Heinrich Stadial 1 (HS1) and Bølling-Allerød (B-A) transition. Xerophyte herbs such as Artemisia, Ephedra, and Amaranthaceae were highest during the late B-A and YD indicating regional aridity. Poaceae (grasses) were maxima in the B-A and EH, probably indicating expansion in the barren areas after deglaciation. Maximum in temperature and humidity during the EH and cooling and aridification in the Middle (MH) and Late Holocene (LH) are indicated by the changes in the abundance of deciduous Quercus and Pinus forest species. Botryococcus algae increased during the Early Holocene, while the rest of the algae almost vanished, which could indicate that the lake became very productive but shallower until 8.2 kyr. The lake level lowered and became seasonal in the Middle-Late Holocene transition, coinciding with the regional climate aridification. Microcharcoal analysis done on the palynological preparations agrees with the vegetation changes, showing maxima in the EH and MH, related with the maximum in regional forest occurrence, and a decrease in the LH when the Mediterranean vegetation, and thus fuel availability, diminished. This record shows evidence of anthropogenic impact in the last centuries by cultivation, reforestation, cattle grazing, enhanced erosion and eutrophication.I + D + i projects CGL2013-47038- R, CGL2017-85415-R, PID2019-1049449GB-I00, and PID2021- 125619OB-C21/C22 funded by Ministerio Ciencia e Innovación/Agencia Estatal de Investigación/ 10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa”I + D + i projects A-RNM-336-UGR20 and P20_00059 of the action “Proyectos I + D + i del Programa Operativo FEDER - Junta de Andalucía - UGR” and the research group RNM-190Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action lineI + D + I project PID2019-1049449 GB-I00 funded by MCIN/AEI/ 10.13039/501100011033/ and FEDER “Una manera de hacer Europa” and the fellowship 20788/PI/18 of Fundación SénecaPredoctoral fellowship BES- 2018-084293 provide by the MCIN/ AEI/ 10.13039/5011000110 33/European Union for her Marie Sklodowska-Curie grant agreement number 892487 under Horizon 2020 fundsMinisterio de Ciencia e Innovación of the Spanish Government for the grant number FJC2020-044215-I of the Juan de la Cierva Formación postdoctoral progra

    Evidences of the Blake and Iceland Basin magnetic excursions in southeastern Iberia and chronological implications for the Padul sedimentary record

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    Acknowledgments This study was supported by the project B-RNM-144-UGR18 and ARNM- 336-UGR20 of the action “Proyectos I + D + i del Programa Operativo FEDER 2018 - Junta de Andalucía-UGR”, the projects CGL2013-47038-R and CGL2017-85415-R, of the “Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER”, and the research group RNM-190 (Junta de Andalucía), and the projects P18-RT-871 and Retos P20_00059 of Junta de Andalucia. A.G.-A. was also supported by a Ram´on y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economía y Competividad). A.L.-A PhD is funded by BES-2018-084293 (Ministerio de Economía y Competividad). We thank the Paleomagnetic Laboratory CCiTUB-Geo3Bcn CSIC for the support on paleomagnetic analysis. LV and EB thank the Geomodels Research Institute (UB). We are very grateful to two anonymous reviewers and to the editor Christian Zeeden.The Padul-15-05 sediment core provides an exceptional perspective of the paleoenvironmental and climate change in the Western Mediterranean region for the last ca. 200 kyr. However, even though a robust chronology mainly relying on radiometric dating is available for the last 50 ka, the chronology for the older sediments is not yet fully resolved. Ages for the bottom part of the core (>21 m) were previously inferred from amino-acid racemization dating and sediment accumulation rates. In this work, we provide a more accurate chronology for the older part (>100 kyr) of the Padul-15-05 sediment core record based on the recognition of past Earth's magnetic excursions. We identify an interval prone of reversed polarity samples close to MIS-5e/5 d transition that we correlate to the Blake geomagnetic excursion (116.5 kyr–112 kyr). In addition, we identify an interval of low inclinations and two reversed samples that we interpret as the Iceland Basin geomagnetic excursion (192.7 kyr–187.7 kyr: wide scenario of VGP <40°). Our new results, which include IRM acquisition curves that contribute to understand the magnetic mineralogy, enhances the robustness of the age model for the Padul-15-05 sedimentary sequence by adding an independent age dataset with new accurate tie-points. Our refined age control together with the available paleoenvironmental and paleoclimate multiproxy data provide insightful information to unveil the response of the western Mediterranean environments to regional environmental and climate change.Project B-RNM-144-UGR18 and ARNM- 336-UGR20 of the action “Proyectos I + D + i del Programa Operativo FEDER 2018 - Junta de Andalucía-UGR”Projects CGL2013-47038-R and CGL2017-85415-R, of the “Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER”Research group RNM-190 (Junta de Andalucía)Projects P18-RT-871 and Retos P20_00059 of Junta de AndaluciaRamón y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economía y Competividad)Funded by BES-2018-084293 (Ministerio de Economía y Competividad

    Millennial-scale cyclical environment and climate variability during the Holocene in the western Mediterranean region deduced from a new multi-proxy analysis from the Padul record (Sierra Nevada, Spain)

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    A high-resolution multi-proxy approach, integrating pollen, inorganic and organic geochemical and sedimentological analyses, has been carried out on the Holocene section of the Padul sedimentary record in the southern Iberian Peninsula reconstructing vegetation, environment and climate throughout the last ~ 11.6 cal kyr BP in the western Mediterranean. The study of the entire Holocene allows us to determine the significant climate shift that occurred during the middle-to-late Holocene transition. The highest occurrence of deciduous forest in the Padul area from ~ 9.5 to 7.6 cal kyr BP represents the Holocene humidity optimum probably due to enhanced winter precipitation during a phase of highest seasonal anomaly and maximum summer insolation. Locally, insolation maxima induced high evaporation, counterbalancing the effect of relatively high precipitation, and triggered very low water table in Padul and the deposition of peat sediments. A transitional environmental change towards more regional aridity occurred from ~ 7.6 to 4.7 cal kyr BP and then aridification enhanced in the late Holocene most likely related to decreasing summer insolation. This translated into higher water levels and a sedimentary change at ~ 4.7 cal kyr BP in the Padul wetland, probably related to reduced evaporation during summer in response to decreased in seasonality. Millennial-scale variability is superimposed on the Holocene long-term trends. The Mediterranean forest regional climate proxy studied here shows significant cold-arid events around ~ 9.6, 8.5, 7.5, 6.5 and 5.4 cal kyr BP with cyclical periodicities (~1100 and 2100 yr) during the early and middle Holocene. A change is observed in the periodicity of these cold-arid events towards ~1430 yr in the late Holocene, with forest declines around ~ 4.7–4, 2.7 and 1.3 cal kyr BP. The comparison between the Padul-15-05 data with published North Atlantic and Mediterranean paleoclimate records suggests common triggers for the observed climate variability, with the early and middle Holocene forest declines at least partially controlled by external forcing (i.e. solar activity) and the late Holocene variability associated with internal mechanisms (oceanic-atmospheric)

    Asistencia a mujeres embarazadas con VIH/sida en Fortaleza, Ceará, Brasil

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    The objective of this study is to analyze the perinatal results of the prophylactic measures adopted in the prevention of the vertical transmission of HIV. The study was carried out using the medical records of 168 women with HIV and their newborns in a public maternity unit of Fortaleza, in the state of Ceará, from 2005 to 2009. The data was obtained between the months of March and September 2010 and was analyzed using the program SPSS 10.0. The women diagnosed before pregnancy received timely care that permitted them an effective antiretroviral therapy and a greater number of check-ups (p&lt;0,05). Antiretroviral therapy was administered to 97.6% of the pregnant women, and triple therapy in 88.7%. AZT was administered intrapartum in 95.2% of the women and oral AZT in syrup to 100% of the newborns. Birth by cesarean section was predominant (92.8%) and was associated to the intrapartum use of AZT when compared to vaginal birth (p&lt;0.001). Cesarean section favored intrapartum administration of AZT.El objetivo de este estudio es analizar los resultados perinatales de las medidas profilácticas adoptadas en la prevención de la transmisión vertical del VIH. Se realizó una investigación de las historias clínicas de 168 mujeres con VIH y sus recién nacidos en una maternidad pública de Fortaleza, estado de Ceará, entre 2005 y 2009. Los datos se obtuvieron entre los meses de marzo y septiembre de 2010 y fueron analizados con el programa SPSS 10.0. Las embarazadas que conocían el diagnóstico en forma previa al embarazo tuvieron una rápida atención que permitió una terapia antirretroviral eficaz y un mayor número de controles (p&lt;0,05). Se administró terapia antirretroviral al 97,6% de las embarazadas, triple esquema al 88,7%; AZT intraparto al 95,2% y AZT oral en jarabe al 100% de los recién nacidos. Predominó la cesárea (92,8%) asociada al AZT intraparto al ser cotejada con el parto vaginal (p&lt;0,001). La cesárea proporcionó mayor administración de AZT intraparto

    Orbital-scale environmental and climatic changes recorded in a new ∼200,000-year-long multiproxy sedimentary record from Padul, southern Iberian Peninsula

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    Padul is one of the few wetland sites in southern Europe and the Mediterranean region that exhibits an unusually large temporal span (&gt;100 kyr) and continuous Quaternary sedimentary record. Previous core-based studies from Padul yielded paleoecological datasets (i.e., pollen and organic geochemistry), but with a poor age control that resulted in rather arbitrary climate inferences. Therefore, precise age control and a multidisciplinary approach is necessary to understand long-term regional environmental and climate change and the associated local response of the Padul wetland environment. Here we present a new long sediment record (Padul-15-05) from this wetland in the southern Iberian Peninsula with the aim of improving the age control of the sedimentary sequence and carrying out up-to-date high-resolution multiproxy analyses. In this study the age control is based on 61 AMS radiocarbon dates for the last ca. 50 kyr BP and on the extent of amino acid racemization (AAR) in mollusc shells extending back ∼118 kyr BP. No numerical ages are available for the bottom part of the core but the sediment accumulation rates (SAR) and the cyclostratigraphic analysis of the multiproxy data suggest that the core preserves a continuous record of the last ∼197 kyr (from late MIS 7 to present) with millennial-scale time resolution. Sedimentological (lithology, magnetic susceptibility, XRD, color), geochemical (XRF, TOC, C/N, % carbonate content) and paleontological (pollen, charophytes, gastropods) data show co-varying cyclical paleoenvironmental changes linked to orbital-scale climatic variability. Silicon, magnetic susceptibility (MS) and total organic carbon (TOC) data show periodicities between ∼26.2–19.6 kyr linked to insolation, which is strongly dominated by precession cycles at this latitude. High values of Si and MS data have been related to high siliciclastic/detrital input from Sierra Nevada range during minima in insolation due to enhanced soil weathering/erosion during regional aridity and lower forest cover recorded by the arboreal pollen, which could also be favored by a minor biogenic productivity. In addition, warm climate conditions during maxima in insolation mostly resulted in negative precipitation/evapotranspiration balance and low lake levels, while cold glacial and stadial periods were mainly characterized by positive precipitation/evapotranspiration balance, and therefore, high lake levels. The improved chronology of the Padul sedimentary sequence along with a multiproxy study permitted us to better relate environmental and vegetation changes to climatic events and to demonstrate how both local (i.e., lake level, sedimentation) and regional (i.e., vegetation) environments responded to orbital-scale climate changes

    Quality Control of Motor Unit Number Index (MUNIX) Measurements in 6 Muscles in a Single-Subject “Round-Robin” Setup

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    Background Motor Unit Number Index (MUNIX) is a neurophysiological measure that provides an index of the number of lower motor neurons in a muscle. Its performance across centres in healthy subjects and patients with Amyotrophic Lateral Sclerosis (ALS) has been established, but inter-rater variability between multiple raters in one single subject has not been investigated. Objective To assess reliability in a set of 6 muscles in a single subject among 12 examiners (6 experienced with MUNIX, 6 less experienced) and to determine variables associated with variability of measurements. Methods Twelve raters applied MUNIX in six different muscles (abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibialis anterior (TA), extensor dig. brevis (EDB), abductor hallucis (AH)) twice in one single volunteer on consecutive days. All raters visited at least one training course prior to measurements. Intra- and inter-rater variability as determined by the coefficient of variation (COV) between different raters and their levels of experience with MUNIX were compared. Results Mean intra-rater COV of MUNIX was 14.0% (±6.4) ranging from 5.8 (APB) to 30.3% (EDB). Mean inter-rater COV was 18.1 (±5.4) ranging from 8.0 (BB) to 31.7 (AH). No significant differences of variability between experienced and less experienced raters were detected. Conclusion We provide evidence that quality control for neurophysiological methods can be performed with similar standards as in laboratory medicine. Intra- and inter-rater variability of MUNIX is muscle-dependent and mainly below 20%. Experienced neurophysiologists can easily adopt MUNIX and adequate teaching ensures reliable utilization of this method

    Ecoescuelas: una estrategia de inclusión de la dimensión ambiental

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    A lo largo de la historia, el resultado de la actividad industrial y la insostenibilidad de los modelos de producción han generado hábitos de consumo no responsables, explosión demográfica, pobreza en sectores urbanos, abandono del sector rural y establecimiento de modelos productivos extractivos; aspectos que han derivado en problemáticas ambientales que han impactado negativamente los ecosistemas y que han producido agotamiento paulatino de los recursos naturales, pérdida de biodiversidad, gestión inadecuada del recurso hídrico, de la energía y de los resi - duos sólidos producidos por el mismo sistema económico, el cual se ha centrado en la concepción de desarrollo como crecimiento económico. Por lo anterior, se evi - dencia la necesidad de transformar la situación descrita y llevar a cabo procesos educativos de manera más concreta, específicamente con los Proyectos Ambien - tales Escolares (PRAE), cuyo fortalecimiento ha constituido una política nacional a partir del Decreto 1743 de 1994. Teniendo en cuenta que la Universidad Libre, desde el Consultorio Ambiental, ha estado asesorando a instituciones educativas en este sentido, además de la experiencia adquirida a partir de los convenios con la Corporación Autónoma Regional, se plantea como objetivo general de investigación: implementar la es - trategia Ecoescuelas para la inclusión de la dimensión ambiental en el currículo y el fortalecimiento de los PRAE en instituciones educativas del departamento de Cundinamarca, involucrando aspectos de gestión pedagógica y ambiental. En este sentido, el libro es una recopilación de las experiencias significativas producto de los procesos de intervención y fortalecimiento de la dimensión ambiental, en el contexto de la investigación-acción participativa, cuyo fin es describir los resultados de aplicación de las herramientas de análisis y diálogo permanente entre los actores educativos desde su rol y área de conocimiento. Se incorporaron aspectos conceptuales, metodológicos y técnicos que permiten la interpretación y el planteamiento de alternativas de solución a problemáticas ambientales. La ambientalización del currículo o inclusión de la dimensión ambiental estipulada en la Política Nacional de Educación Ambiental implica introducir contenidos ambientales en las diferentes áreas del conocimiento como parte del diseño, desarrollo y evaluación de los PRAE, y desde este marco se sustenta el estudio. Por lo anterior, los objetivos específicos que orientaron el proceso partieron de la identificación de las problemáticas ambientales prioritarias del entorno escolar y del análisis documental del Proyecto Educativo Institucional y de los componentes del PRAE de las instituciones educativas, empleando herramientas de diagnóstico participativo. Posteriormente, se implementó un proceso de formación con los docentes de las instituciones educativas, en el cual se abordaron temáticas de construcción de los PRAE, ecoeficiencia y ambientalización curricular y construcción de matrices de transversalización; así como la instalación, puesta en marcha y seguimiento de estrategias técnicas de gestión ambiental en los componentes de ahorro y uso eficiente del agua, de la energía, del manejo adecuado de residuos sólidos, del mejoramiento del entorno y de la biodiversidad y la gestión del riesgo. El libro está organizado en dos partes: la primera se centra en aspectos metodológicos, en la que se describen las etapas de la estrategia empleada durante la intervención en las instituciones educativas. También describe (capítulo 2) el referente teórico del proyecto, plantea el problema de investigación y presenta un análisis de resultados de inclusión de la dimensión ambiental en 33 instituciones educativas de Cundinamarca, desde el enfoque de Ecoescuelas, así como las contribuciones del proyecto. El enfoque mencionado se ubica en el contexto de la sostenibilidad, y concibe la escuela como un sistema complejo donde se visibiliza una oportunidad para la innovación curricular y la integración de aspectos ecológicos ambientales con el quehacer y las buenas prácticas ejecutadas por la comunidad educativa. La segunda parte del libro presenta seis experiencias concretas de intervención, que constituyeron el trabajo de grado en Ingeniería Ambiental de estudiantes participantes en el proyecto. Finalmente, se presentan las conclusiones del estudio realizado. Por cada institución se describen diferentes iniciativas a partir de la aplicación de las cuatro etapas de la estrategia metodológica propuesta, teniendo en cuenta aspectos como ubicación (ya sea rural o urbana), resultados del diagnóstico, características de los documentos institucionales, componentes ambientalespriorizados y necesidad de estrategias técnicas para el fortalecimiento del proceso ambiental institucional. Los resultados han permitido generar planes de acción a corto, mediano y largo plazo en las instituciones educativas, teniendo como fundamento el PRAE y su fortalecimiento desde las dimensiones pedagógica, social y técnica con un enfoque de gestión ambiental como aporte para la transformación en escuelas ecoeficientes, orientadas hacia modelos ambientalmente sostenible

    Repli-Fósil-3D: Aplicación técnicas de replicación 3D para la mejora de las colecciones utilizadas en la docencia práctica del área de Paleontología

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    En este proyecto se ha pretendido perfeccionar la docencia práctica de las asignaturas del ámbito de la Paleontología y de las actividades divulgativas impartidas por el departamento de Estratigrafía y Paleontología, y por lo tanto mejorar el grado de aprendizaje del alumnado, mediante el uso de modelos y réplicas impresas en 3D de diferentes grupos fósiles que, por diversos motivos (escasez de muestras en nuestros laboratorios, tamaño o fragilidad), no pueden ser correctamente observados y/o manipulados por el alumnado. Esto ha permitido al profesorado del área de Paleontología adaptar las prácticas docentes y actividades divulgativas a los requerimientos de la sociedad y universidad actuales.The aim of this project has been to improve the practical teaching of subjects in the field of Paleontology and in other dissemination activities carried out by the Department of Stratigraphy and Paleontology, in order to enhance the student learning. To do so, this project printed 3D models and replicas of different fossil groups which, for various reasons (scarcity of samples in our laboratories, size or fragility), cannot be correctly observed and/or manipulated by students. This has allowed the teaching staff of the Paleontology area to adapt their teaching practices and dissemination activities to the requirements of today's society and university
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