44 research outputs found

    Seismic source in the Iberian-African plate boundary

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    The plate boundary between Iberia and Africa has been studied using data on seismicity and focal mechanisms. The region has been divided into three areas: A; the Gulf of Cadiz; B, the Betics, Alboran Sea and northern Morocco; and C, Algeria. Seismicity shows a complex behavior, large shallow earthquakes (h < 30 km) occur in areas A and C and moderate shocks in area B; intermediate-depth activity (30 < h < 150 km) is located in the depth earthquakes (h » 650 km) are located to the south of Granada. Moment rate, slip velocity and b values have been estimated for shallow shocks, and show similar characteristics for the Gulf of Cadiz and Algeria, and quite different ones for the central region. Focal mechanisms of 80 selected shallow earthquakes (8 ‡ mb ‡ 4) show thrust faulting in the Gulf of Cadiz and Algeria with horizontal NNW-SSE compression, and normal faulting in the Alboran Sea with E-W extension. Focal mechanisms of 26 intermediate-depth earthquakes in the Alboran Sea display vertical motions, with a predominant plane trending E-W. Solutions for very deep shocks correspond to vertical dip-slip along N-S trends. Frohlich diagrams and seismic moment tensors show different behavior in the Gulf of Cadiz, Betic-Alboran Sea and northern Morocco, and northern Algeria for shallow events. The stress pattern of intermediate-depth and very deep earthquakes has different directions: vertical extension in the NW-SE direction for intermediate depth earthquakes, and tension and pressure axes dipping about 45 ° for very deep earthquakes. Regional stress pattern may result from the collision between the African plate and Iberia, with extension and subduction of lithospheric material in the Alboran Sea at intermediate depth. The very deep seismicity may be correlated with older subduction processes

    Electrical resistivity tomography: fundamentals and applications

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    En este cuaderno se describe el método de tomografía eléctrica y sus principales aplicaciones, mostrándose como ejemplo algunos de los resultados obtenidos en diversos estudios. El método de tomografía eléctrica se utiliza ampliamente en estudios de geología, de geotecnia y de hidrogeología. Al tratarse de un método no destructivo, es muy apropiado en estudios arqueológicos, ofreciendo resultados con un alto grado de detalle.This notebook describes the method of electrical resistivity tomography and its main applications and provides examples of the results obtained in various studies. Geological, geotechnical and hydrogeological studies often use the electrical resistivity tomography method. As it is a non-destructive method, it is very appropriate in archaeological studies, offering results with a high degree of detail.Parte de la realización de estos cuadernos ha sido financiada a través del proyecto GR18028 (Grupo de investigación RNM026) el cual ha sido cofinanciado por los Fondos Europeos de Desarrollo Regional (FEDER) y el Gobierno de Extremadura

    Tomografía eléctrica: Fundamentos y aplicaciones

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    En este cuaderno se describe el método de tomografía eléctrica y sus principales aplicaciones, mostrándose como ejemplo algunos de los resultados obtenidos en diversos estudios. El método de tomografía eléctrica se utiliza ampliamente en estudios de geología, de geotecnia y de hidrogeología. Al tratarse de un método no destructivo, es muy apropiado en estudios arqueológicos, ofreciendo resultados con un alto grado de detalle.This notebook describes the method of electrical resistivity tomography and its main applications and provides examples of the results obtained in various studies. Geological, geotechnical and hydrogeological studies often use the electrical resistivity tomography method. As it is a non-destructive method, it is very appropriate in archaeological studies, offering results with a high degree of detail.Parte de la realización de estos cuadernos ha sido financiada a través del proyecto GR18028 (Grupo de investigación RNM026) el cual ha sido cofinanciado por los Fondos Europeos de Desarrollo Regional (FEDER) y el Gobierno de Extremadura

    Early geomagnetic data from the Astronomical Observatory of Madrid (1879–1901)

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    La recuperación de los primeros datos geomagnéticos es esencial para mejorar el conocimiento de la evolución del campo geomagnético. Se describe un conjunto de datos recuperados recientemente que incluye valores medios decádicos (10 días) de la declinación geomagnética y algunos valores dispersos de inclinación geomagnética medidos en el Observatorio Astronómico de Madrid desde 1879 hasta 1901. Estos datos recuperados se comparan directamente con los resultados obtenidos de un modelo geomagnético. Los datos se han puesto ahora a disposición de la comunidad científica en forma digital.The recovery of early geomagnetic data is essential to improve knowledge of the evolution of the geomagnetic field. A recently recovered dataset is described that includes mean decadal (10 days) values of the geomagnetic declination and some disperse values of geomagnetic inclination measured at the Astronomical Observatory of Madrid from 1879 to 1901. These recovered data are compared directly with the results obtained from a geomagnetic model. The data have now been made accessible for the scientific community in digital form.• Ministerio de Economía y Competitividad. Becas AYA2014-57556-P y CGL201787917-P • Junta de Extremadura. Beca GR15137 e IB16127peerReviewe

    Prospecção geoarqueológica de estruturas megalíticas com recurso a georadar (Almendralejo, Espanha)

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    In 1980, in Almendralejo, Spain, it was discovered the Tomb of Huerta Montero, a megalithic funerary monument, the best preserved in the Iberian Peninsula, dating from the Chalcolithic (Copper Age, about 4650 BC). According to the opinion of archaeologists, it is quite probable that there are similar buried monuments in the vicinity of the known tomb. This suspicion led to the geophysical study, carried out with the aim of identifying new structures in the vicinity of the necropolis discovered. The choice of geophysical method it was the GPR, because it is a non-invasive technique, accurate and rapid in its implementation. The results obtained allow us to conclude that there may be a structure of circular shape, with a diameter of about 7 m which may to correspond to a funeral monument as there are a few meters, with a temporal thickness ranging between 13 and 21 ns deep. In the northern part of the structure there are two protrusions that may match an entry in the building or even the rest of the tunnel entrance

    ¿Qué aprenden unos estudiantes en una experiencia formativa de Didáctica de las Ciencias Experimentales en el Grado de Educación Infantil?

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    This research aims to find out if the initial knowledge of Early Childhood Education teachers in their initial training in science teaching evolves. The experience was carried out with students in the 3rd year of the Degree in Early Childhood Education, after working on the proposal ?How to teach the human body and healthy habits in Early Childhood Education. We have used a non-experimental quantitative design with pretest and posttest. The results show the achievements, but also reveal, worryingly, the shortcomings with which teachers present and the insufficient evolution after this first intervention. This is a wake-up call to ask what we can do to improve their initial training

    Duration of estrus and preovulatory surge of LH in Boer x Nubian goats synchronized with various hormones in tropical latitude of Mexico

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    The objective was to determine the duration of estrus, preovulatory surge of luteinizing hormone (LH), fertility and prolificacy of Boer x Nubian goats in tropical Mexico (19º29’LN) synchronized with fluorogestone acetate (FGA) and prostaglandin F2 (PGF2) combined with gonadotrophin-releasing hormone (GnRH) or equine chorionic gonadotrophin (eCG). The treatments were: T1 (FGA, n = 5), T2 (FGA + GnRH, n = 7), T3 (FGA + eCG, n = 8), T4 (PGF2 + GnRH, n = 5) and T5 (PGF2 + eCG, n = 7). The responses measured were percentage of animals showing estrus, duration of estrus (h), fertility (%), prolificacy (kids/parturition); intervals (h) from end of treatment til estrus and til peak preovulatory LH concentration, from onset of estrus til peak LH; duration of peak LH (h), and LH concentration (ng/mL). Duration of estrus was longest in goats of T3 (35.2 ± 1.4). Onset of estrus differed (P&lt;0.05) between T2 and T3 (27.9 ± 1.2 vs. 17.2 ± 1.2). Use of PGF2 (T4 and T5) delayed onset of estrus compared with T2 and T3. Interval between sponge withdrawal and onset of LH peak was shorter in T3 than T2 (P&lt;0.05), while that from onset of estrus to LH peak was shorter (P&lt;0.05) with eCG, injection than with GnRH. There were no differences in length and breadth neither of the preovulatory LH surge nor in fertility or litter size (P&gt;0.05). The use of GnRH, either with PGF2 or FGA, increased the time from onset of estrus to LH peak, whereas the use of eCG shortened it

    Radiografía de un castro de la Edad del Hierro: arqueología no invasiva en el asentamiento de Villasviejas del Tamuja (Botija, Cáceres)

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    The aim of this paper is to present the progress that has been made in the study of the hillfort of Villasviejas del Tamuja (Botija, in the province of Cáceres), based on a combination of non-destructive techniques. The possibility of cross-referencing the results obtained with different geophysical methods (magnetometry, georadar and electric tomography) raises the opportunity to formulate a reliable diagnosis on the spatial organization of this site. The most relevant results are described, and their contribution to a general interpretation of the urban structure and morphology of domestic spaces is analyzed. This information is contrasted with previously available excavation data and its framing is analysed within the existing knowledge on this type of settlements. In addition, elements of interest about the diachronic evolution of the site are added, which are relevant in relation to the hypotheses formulated about the impact of the Roman conquest. Ultimately, the potential of this type of research strategy for the study and revaluation of large and complex archaeological zones is considered.El objetivo de este trabajo es proporcionar un primer avance del estudio del castro de Villasviejas del Tamuja (Botija, provincia de Cáceres) a partir de la combinación de técnicas no destructivas. La posibilidad de cruzar los resultados obtenidos con diversos métodos geofísicos (magnetometría, georradar y tomografía eléctrica) plantea la oportunidad de formular un diagnóstico fiable sobre la organización espacial de este enclave.Se describen los resultados más relevantes, y se valora su aportación para una interpretación general de la estructura urbana y la morfología de los espacios domésticos. Esta información es contrastada con los datos de excavación previamente disponibles, y se analiza su encuadre dentro del conocimiento actualmente existente sobre este tipo de asentamientos. Asimismo, se añaden elementos de interés acerca de la evolución diacrónica del sitio, que son relevantes en relación con las hipótesis formuladas acerca del impacto de la conquista romana.En última instancia se pondera el potencial de este tipo de estrategias de investigación para el estudio y revalorización de zonas arqueológicas grandes y complejas

    Caracteristicas reproductivas de ovejas Pelibuey sincronizadas e inducidas a la pubertad

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    El objetivo del experimento fue analizar las características reproductivas de ovejas Pelibuey sincronizadas (T1: n = 7) e inducidas a la pubertad (T2: n = 7). Las ovejas del T1 se presincronizaron, siete días después se aplicó a todas las ovejas FGA intravaginal durante 12 d y dos días antes de retirar el FGA se aplicó eCG. La incidencia de estro fue de 100 % en T1 y T2. El inicio del estro no fue diferente (P&gt;0.05) con valores 21.4 ± 2.2 h y 24.2 ± 3.2 h para T1 y T2. La duración del estro fue de 60.5 ± 6.6 y 41.3 ± 3.6 para T1 y T2 (P&lt;0.05). El inicio, duración y amplitud del pulso preovulatorio de LH no mostró diferencias con valores de 24.5 ± 1.7 y 24.2 ± 4.7 h, 13.4 ± 1.2 y 14.0 ± 0.6 h, 18.1 ± 2.7 y 21.3 ± 3.1 ng mL-1 para T1 y T2 respectivamente. La tasa de gestación no fue diferente con 100 y 85.71 % para T1 y T2. La tasa ovulatoria y prolificidad fue diferente (P&lt;0.05) con valores de 4.4 ± 1.2 y 2.7 ± 0.4 y 2.5 ± 0.2 y 1.4 ± 0.4, para el T1 y T2 respectivamente. Se concluyó que el uso de FGA y eCG en ovejas Pelibuey es recomendable para inducir la pubertad, ya que las características reproductivas analizadas son aceptables, su implementación puede ser factible en programas de inseminación a tiempo fijo

    Non invasive exploration of a late republican fortified settlement in the mid Tagus valley. The site of Cerro de la Breña (Talaván, Cáceres)

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    En este trabajo se muestran los primeros resultados de una exploración del asentamiento fortificado del Cerro de la Breña (Talaván, Cáceres), principalmente mediante la combinación de una batería de sistemas de registro no invasivos (prospección geomagnética, georradar, tomografía eléctrica y LiDAR). Los resultados acreditan la existencia de un complejo sistema defensivo, que encerraría una trama urbana densa y regular. Estos datos son valorados a la luz del conocimiento previo que existía sobre el sitio, para así poder avanzar una lectura en términos históricos del sentido de este asentamiento. Este marco se define como un proceso de transformación de la estructura territorial del valle medio del Tajo (actual Alta Extremadura) a caballo entre el final de la Edad del Hierro y los primeros momentos de la dominación romana. Se valora en este sentido el contexto geográfico y la evidencia disponible sobre otros sitios arqueológicos del entorno. La propuesta de interpretación se orienta a considerar al Cerro de la Breña como un asentamiento directamente vinculado con la implantación romana entre finales del siglo II e inicios del siglo I a.C.This paper shows the first results of an exploration of the fortified settlement of Cerro de la Breña (Talaván, Cáceres), mainly through the combination of non-invasive methods (geomagnetic survey, GPR, electric tomography and Li- DAR). The results prove the existence of a complex defensive system, which would enclose a dense and regular urban layout. These data are valued in light of the previous knowledge about the site, in order to advance an interpretative proposal in functional and historical terms about this settlement. This framework is the process of transformation of the territorial structure of the middle Tagus valley (now Alta Extremadura) between the end of the Iron Age and the first moments of Roman domination. In this sense, the geographical context and the available evidence on other archaeological sites in the area are valued. The interpretation is oriented to consider Cerro de la Breña as a settlement directly linked to the Roman implantation between the end of the 2nd century and the beginning of the 1st century BC
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