482 research outputs found

    Gender studies and feminist film theory as a theoretical and methodological framework for research in Audiovisual Culture

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    El artículo presenta como objetivo fundamental la reivindicación de la teoría fílmica feminista y de los Estudios de Género como un marco teórico competente y unas metodologías adecuadas para la investigación en Comunicación Audiovisual. Para ello desarrolla un análisis de las fuentes así como un discernimiento sobre el valor de las metodologías y una puesta en diálogo de las diferentes líneas de investigación que confluyen en los estudios audiovisuales (como, por ejemplo, el estructuralismo, la semiótica, el psicoanálisis, la hermenéutica, la fenomenología, estética y el análisis textual) posicionando, en dicho contexto, la aportación de los Estudios de Género y de la Teoría Fílmica Feminista y mostrando como resultado, de este modo, su validez metodológica más allá de ciertos posicionamientos positivistas, en lo que Casetti ha venido en denominar “teorías de campo”. Dicho de otra manera, se muestra la posibilidad de una vuelta a posiciones metodológicas de corte teórico y que profundizan en un sentido crítico desde una investigación posicionada que pretende dar con las preguntas adecuadas para su objeto de estudio que tiene que ver con la visión, la representación, la construcción de la subjetividad y de la identidad, el placer y la cultura contemporánea así como la lógica interna, los procesos de significación y el análisis de contenido de los textos audiovisuales, afirmando tanto su interdisciplinariedad como su apertura comprehensiva propiciando ver la práctica del audiovisual como una práctica de producción de significado que envuelve tanto al director como al espectador en una relación dialéctica como una práctica social (Johnston).The fundamental objective that this paper presents is the vindication of the feminist film theory and gender etudies as a competent theoretical framework with adequate research methodologies in audiovisual communication. It develops an analysis of the sources as well as an insight into the value of the methodologies and a commissioning in dialogue of the different lines of research that converge in media studies (for example, Structuralism, Semiotics, Psychoanalysis, Hermeneutics, Phenomenology, Aesthetics and Textual Analysis) positioning, in this context, the contribution of gender studies and the feminist film theory and showing as a result, thereby, their methodological validity beyond certain positivist positions, in what Casetti has come to call “field theories”. In other words, it shows the possibility of a return to theoretical methodological positions and a deepening into a critical sense from a positioned research that aims to find the right questions to its subject matter which is related to the vision, representation, the construction of subjectivity and identity, pleasure and contemporary culture as well as the internal logic, the processes of meaning and content analysis of audiovisual texts, claiming both its interdisciplinarity and its comprehensive opening in favour of seeing the audiovisual practice as a ‘meaning production’ practice that surrounds both the director and the audience in a dialectical relationship as a social practice (Johnston) audiovisual production “as a practice of meaning-production involving both filmmaker and filmviewer in a dialectical relationship — as a social practice” (Johnston)

    Critical behavior of the ferromagnetic transition in GdSc(Si,Ge) intermetallic compounds

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    A complete study on the critical behavior of the paramagnetic to ferromagnetic transition in intermetallics GdScSi, GdScGe, GdSc(Si0.5Ge0.5) and Gd(Sc0.5Ti0.5)Ge has been carried out by means of magnetic as well as calorimetric measurements, using a high resolution ac photopyroelectric technique. The critical exponents alfa, beta, gamma, delta and the ratio of the critical coefficients A+/A- have been independently obtained for the four samples. It has been proved that the magnetic interactions are short range as the values of the critical parameters correspond to the 3D-Heisenberg class, stating an isotropic ordering of the Gd spins. In some cases, there are small deviations of some of the critical parameters from the theoretical values which have been discussed on the basis of the variation of the d states hybridization between the rare earth and the transition metal, as well as the presence of small magnetocrystalline anisotropies arising from spin-orbit coupling effects.This work has been supported by Universidad del País Vasco UPV/EHU (GIU16/93)

    Las asociaciones de microfauna como indicadores de cambios paleoambientales en los ciclos fluvio-lacustres Miocenos (NE de la Cuenca del Duero, España)

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    The siliclastic and carbonate deposits are interbedded in the Villadiego area (Miocene, NE Duero Basin). They have been subdivided into two high-rank depositional sequences: DDS and CDS. The sedimentary analysis of these units and the study of the microfauna content, mainly ostracods, led to the identification of lacustrine-fluvial interaction systems. The sedimentary characteristics reveal the existence of fluvial systems of gravel, flood plains and lacustrine systems that were interconnected and intimately related in north-south direction. In the sedimentological analysis, thirteen types of fluvial and lacustrine lithofacies and six genetic facies associations were recognized. The top of DDS is the result of lake level risings. The CDS shows a deepening-shallowing cycle. The ostracod micropaleontological analysis of the sediments have been studied, with the aim of reconstructing the palaeoenvironmental evolution of this area. These microfauna assemblages integrated with the analysis of the sedimentary facies allowed to conclude the existence of lakes with a water-bearing level of few tens of meters. A change in the chemical conditions of the waters, which evolved from oligohaline and carbonated to mesohaline and sulphated is concluded.Los depósitos siliciclásticos y carbonatados se encuentran intercalados en el área de Villadiego (Mioceno, NE cuenca del Duero). Se han subdividido en dos secuencias de depósito de alto rango: DDS y CDS. El análisis de estas unidades sedimentarias y el estudio del contenido de microfauna, principalmente ostrácodos, condujo a la identificación de sistemas de interacción lacustre-fluvial. Las características sedimentarias revelan la existencia de los sistemas fluviales de grava, llanuras de inundación y sistemas lacustres que estaban interconectados e íntimamente relacionados en dirección N-S. En el análisis sedimentológico se reconocieron trece tipos de litofacies fluviales y lacustres y seis asociaciones de facies genéticas. La parte superior del DDS es el resultado de levantamientos del nivel del lago. El CDS muestra un ciclo de profundización-somerización. Los sedimentos se han estudiado mediatne análisis micropaleontológico de ostrácodos, con el objetivo de reconstruir la evolución paleoambiental de esta zona. Estos conjuntos de microfauna integrados con el análisis de las facies sedimentarias permiten concluir la existencia de lagos con un nivel acuífero de pocas decenas de metros. Se concluye que existió un cambio en las condiciones químicas de las aguas, que evolucionaron a partir de oligohalinos y sin gas a mesohalino y sulfatadas

    A multi-wavelength view of the central kiloparsec region in the Luminous Infrared Galaxy NGC1614

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    The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Pa-alpha, optical, and X-ray observations of NGC1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array (VLA) and the Gemini/T-ReCS 8.7 micron emission, as well as the Pa-alpha line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used an HST/NICMOS Pa-alpha map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power-law for each individual region within the central kpc of NGC1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an AGN, but rather by a compact (r < 90 pc) starburst. Chandra X-ray data also show that the central kpc region is dominated by starburst activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the starburst ring and a putative AGN in NGC1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.Comment: 13 pages, 7 figures, 5 tables. Accepted for publication in Ap

    Study of the magnetocaloric effect in intermetallics RTX (R = Nd, Gd; T = Sc, Ti ; X = Si, Ge)

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    A detailed study of the magnetocaloric properties of six compounds of the intermetallic family RTX (R = Nd, Gd; T = Sc, Ti ; X = Si, Ge) has been undertaken: NdScSi, NdScGe, GdScSi, GdScGe, GdSc(Si0.5Ge0.5) and Gd(Sc0.5Ti0.5)Ge. The magnetic entropy changes at the Curie temperature TC and the refrigerant capacities signal that they are competitive magnetocaloric materials, showing that an improvement can be obtained by tuning the composition, as Gd(Sc0.5Ti0.5)Ge presents the best properties. These magnetocaloric variables fulfill the scaling equations with the critical parameters corresponding to the universality classes to which the ferromagnetic transitions belong (3D-XY, 3D-Heisenberg, Mean field). For each compound, a universal curve has been found for the rescaled magnetic entropy changes obtained at different applied fields, whose behavior at temperatures below TC indicate the relevance of taking into account the demagnetization field. Finally, it has been demonstrated that the rescaled magnetic entropy changes for the compounds which share the same universality class collapse onto a single universal curve.This work has been supported by Universidad del País Vasco UPV/EHU (GIU16/93)

    Petrophysical characterization of the Dolomitic Member of the Boñar Formation (Upper Cretaceous; Duero Basin, Spain) as a potential CO2 reservoir

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    La Formación Boñar (Cretácico Superior) es una sucesión carbonática que aflora al Norte de la Cuenca del Duero (España). Según datos previos, el Miembro Dolomítico de esta formación es el que muestra características petrográficas más favorables para almacenamiento geológico de CO2. El principal objetivo de este trabajo es el aporte de elementos de juicio que apoyen, clarifiquen y concreten –a un nivel de estudio preliminar– la potencialidad del Miembro Dolomítico de la Formación Boñar como roca almacén. La Formación Boñar (Cretácico Superior) es una sucesión carbonática que aflora al Norte de la Cuenca del Duero (España). Según datos previos, el Miembro Dolomítico de esta formación es el que muestra características petrográficas más favorables para almacenamiento geológico de CO2. El principal objetivo de este trabajo es el aporte de elementos de juicio que apoyen, clarifiquen y concreten –a un nivel de estudio preliminar– la potencialidad del Miembro Dolomítico de la Formación Boñar como roca almacén.Boñar Formation (Upper Cretaceous) is a mainly carbonate succession, which outcrops in the North of Duero Basin (Spain). According to the existing data, the Dolomitic Member of this formation appears to be the most suitable for geological storage of CO2. The main objective of this study is to find evidence to support, clarify and specify –at an initial level– the potential of the Dolomitic Member of the Boñar Formation as a geological reservoir. The study covers density, porosity and permeability tests on samples obtained from the outcrop of the succession near the village of Boñar (León). According to the analysis and interpretation of the mentioned petrophysical properties, the porosity of the Dolomitic Member is within the acceptable range for CO2 geological storage, but the permeability values are far too low. This minimizes the possibilities of the Dolomitic Member –and probably of the whole Boñar Formation– to become an appropriate CO2 reservoir

    Peculiar magnetocaloric properties and critical behavior in antiferromagnetic Tb3Ni with complex magnetic structure

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    A study on the magnetocaloric properties of a Tb3Ni single crystal (which crystallizes in the orthorhombic Pnma space group) has been undertaken and combined with the study of the character and critical behavior of its magnetic transitions. It presents two important magnetocaloric effects in the temperature range 3–90 K due to the richness and variety of its temperature and magnetic field induced phase transitions. There is a conventional (direct) magnetocaloric effect with a maximum at 65 K and very competitive properties:  = 16.6 J/kgK, RCFWHM = 432 J/kg, with a 50 K span, for μ0ΔH = 5 T, which is due to the transition from a magnetically ordered state to the paramagnetic (PM) state with a combined antiferromagnetic to ferromagnetic (AFM-FM) metamagnetic transition. Besides, it also presents an inverse magnetocaloric effect at very low temperature for which the presence of metamagnetic transitions between AFM and FM states is responsible (=19.9 J/kgK, RCFWHM = 245 J/kg, with a 15 K span, for μ0ΔH = 5 T). At low field (<2 T), the character of the AFM-PM transition which takes place at ≈ 61 K has been well established to be second order and governed by short range order interactions, as the critical parameters α, A+/A- obtained from the specific heat at μ0H = 0 T point to the 3D-Heisenberg universality class. Conversely, the metamagnetic transitions between AFM and FM states, which appear for magnetic fields higher than 2 T, have a first order character, as proved by the magnetization behavior as a function of field and temperature. These properties make this material extremely interesting for magnetic refrigeration applications in the gas liquefaction range 4–77 K.This work has been supported by Universidad del País Vasco UPV/EHU (GIU16/93). A. Herrero thanks the Department of Education of the Basque Government as grantee of the programme “Programa Predoctoral de Formación de Personal Investigador No Doctor”. The authors thank for technical and human support provided by SGIker of UPV/EHU. This work was also supported by Russian Science Foundation (project No. 18-72-10022)

    Critical behavior study of magnetic transitions in Dy3Co single crystals

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    An ac photopyroelectric calorimeter has been used to study the critical behaviour of the magnetic transitions in Dy3Co measuring thermal diffusivity, specific heat and thermal conductivity, at low temperature. There are two phase transitions, both of which present singularities in the three variables. The antiferromagnetic to paramagnetic phase transition at 42 K complies with the short range, isotropic universality class, 3D-Heisenberg (alfaexp = -0.133 for specific heat, bexp = -0.145 for thermal diffusivity, alfatheor = btheor = -0.13). In the case of the lower transition where there is a rearrangement of the antiferromagnetic spin ordering at 32 K the critical behavior shows a deviation from isotropy. These results are linked to magnetic measurements already found in literature.This work has been supported by Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU-GIU16/93) and also partially supported by FASO of Russia (themes No 01201463328 and 01201463334)

    Magnetocaloric properties, magnetic interactions and critical behavior in Ho6(Fe,Mn)Bi2 intermetallics

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    Four polycrystaline Fe2P-type Ho6(Fe,Mn)Bi2 intermetallic compounds (space group , No. 189, hP9) have been studied using magnetic techniques in order to explore their ability as magnetocaloric materials, and study the critical behavior of the paramagnetic (PM) to ferromagnetic (FM) transitions to obtain a deeper understanding of the range of the magnetic interactions. The obtained critical exponents β, γ and δ for the four compounds studied (Ho6MnBi2, Ho6FeBi2, Ho6(Mn0.5Fe0.5)Bi2, Ho6(Mn0.75Fe0.25)Bi2) point to long-range order interactions, as they are close to those of the Mean Field Universality class. All of the compounds show relevant magnetocaloric properties over a very broad temperature range, limited by the PM-FM transition and a spin-reorientation one, well separated in all cases. They present very high values of the refrigerant capacities (from 520 J/kg to 709 J/kg at 5 T), good magnetic entropy changes (from 3.4 to 5.7 J/(kgK) at 5 T), and a flat and wide temperature span for the working temperature range (nearly 200 K for Ho6MnBi2, 80 K for Ho6FeBi2 at 5T). The change in properties with composition proves that the magnetocaloric properties can be tuned in Fe2P-type compounds to accommodate different refrigeration applications. Finally, the magnetocaloric scaling laws have been successfully tested and universal curves for the magnetic entropy change have also been obtained in the PM-FM transition region.This work has been supported by Universidad del País Vasco UPV/EHU (GIU16/93)

    Magnetocaloric properties and unconventional critical behavior in (Gd,Tb)6(Fe,Mn)Bi2 intermetallics

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    The magnetic and magnetocaloric properties of the intermetallic family (Gd,Tb)6(Fe,Mn)Bi2 have been studied from 2 K to temperatures above the respective Curie temperatures TC. The substitution of Gd by Tb (Gd6FeBi2, Gd3Tb3FeBi2, Tb6FeBi2) tunes TC in the range 350-250 K and favors the apparition of a metamagnetic transition at very low temperature (below 10 K) from a complex magnetic state to a ferromagnetic one, as well as a spin reorientation transition below Tm = 72 K. As a consequence, an important inverse magnetocaloric effect (IMCE) appears below 20 K and an interesting direct magnetocaloric effect (DMCE) appears over a wide temperature span between TC and Tm with maxima at those temperatures. The partial substitution of Fe by Mn in Tb6Fe0.5Mn0.5Bi2 shifts these effects upwards in temperature while expanding the region of the direct magnetocaloric effect between 70 and 400 K. The combination of adjoint IMCE and DMCE as well as the wide span of the latter shows that tuning this family allows to locate the magnetocaloric effect in different regions of interest. The critical behavior of the PM-FM transitions has been studied obtaining the critical exponents α, β, γ, δ and checking that the respective magnetocaloric effects also scale with the critical parameters n and δ. The transition in Gd6FeBi2 belongs to the Heisenberg universality class with deviations due to magnetocrystalline anisotropies; the critical exponents for Gd3Tb3FeBi2 (in agreement with the Mean Field model) suggest the presence of long range order magnetic interactions, while Tb6FeBi2 and Tb6Fe0.5Mn0.5Bi2 present an unconventional critical behavior aligned with long range order interactions.This work has been supported by Universidad del País Vasco UPV/EHU (project GIU19/305) and the Russian Fund for Basic Research (project N° 20-03-00209-a). A. Herrero thanks the Department of Education of the Basque Government as grantee of the programme “Programa Predoctoral de Formación de Personal Investigador No Doctor”. The authors thank for technical and human support provided by SGIker of UPV/EHU
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