999 resultados para Vasilachis, Irene
Resumo:
Thin Cd(2)Nb(2)O(7) films were grown on single-crystal p-type SiO(2)/Si substrates by the metallo-organic decomposition (MOD) technique. The films were investigated by X-ray diffraction, X-ray energy-dispersive spectroscopy, and field emission scanning electron microscopy, and showed a single phase (cubic pyrochlore), a crack-free spherical grain structure, and nanoparticles with a mean size of about 68 nm. A Cauchy model was also used in order to obtain the thickness and index of refraction of the stack layers (transparent layer/SiO(2)/Si) by spectroscopic ellipsometry (SE). The dielectric constant (K) of the films was calculated to be about 25 from the capacitance-voltage (C-V) measurements. (c) 2008 Elsevier Ltd. All rights reserved.
Resumo:
Results of the study of Argiudolls in two localities (Zarate and Veronica) of the Pampean plain, Argentina, are presented in this contribution. This is a typical area covered by loess. The magnetic studies carried out allowed to determine the presence of detrital magnetite and titanomagnetite, as well as maghemite, pedogenic goethite and superparamagnetic particles (SP). In Veronica soils, a depletion of ferromagnetic minerals is recorded The dominant process in these soils has been the reductive loss of detrital magnetite and titanomagnetite. This is associated with a greater degree of evolution of the soil, which is determined by the concentration and type of detected clays. The higher clay concentration in these soils facilitated reducing conditions and a greater loss of detrital magnetic particles. The loss is reinforced under poor drainage conditions. In the poorly drained soil of Zarate, a concentration of magnetic particles is observed in the Bt horizon, which is associated with an illuviation process. The well drained soil of the same locality shows neoformation of SP particles. These particles would have an ephemeral life until a new wet period in the annual cycle occurs. Although some characteristics of the magnetic signal appear reinforced by the conditions of drainage, this aspect does not seem to be too significant, at least in the Pampean region with low topographic gradients.
Resumo:
Magnetic fabric and rock magnetism studies were performed on apparently isotropic granite facies from the main intrusion of the Lavras do Sul Intrusive Complex pluton (LSIC, Rio Grande do Sul, South Brazil). This intrusion is roughly circular (similar to 12 x 13.5 km), composed of alkali-calcic and alkaline granitoids, with the latter occupying the margin of the pluton. Magnetic fabrics were determined by applying both anisotropy of low-field magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM). The two fabrics are coaxial. The parallelism between AMS and AARM tensors excludes the presence of a single domain (SD) effect on the AMS fabric of the granites. Several rock-magnetism experiments performed in one specimen from each sampled site show that for all sites the magnetic susceptibility is dominantly carried by ferromagnetic minerals, while mainly magnetite carries the magnetic fabrics. Lineations and foliations in the granite facies were successful determined by applying magnetic methods. Magnetic lineations are gently plunging and roughly parallel to the boundaries of the pluton facies, except at the few sites in the central facies which have a radial orientation pattern. In contrast, the magnetic foliations tend to follow the contacts between the different granite facies. They are gently outerward-dipping inside the pluton, and become either steeply southwesterly dipping or vertical towards its margin. The lack of solid-state and subsolidus deformations at outcrop scale and in thin sections precludes deformation after full crystallization of the pluton. This evidence allows us to interpret the observed magnetic fabrics as primary in origin (magmatic) acquired when the rocks were solidified as a result of processes reflecting magma flow. The foliation pattern displays a dome-shaped form for the main LSIC-pluton. However, the alkaline granites which outcrop in the southern part of the studied area have an inward-dipping foliation, and the steeply plunging magnetic lineation suggests that this area could be part of a feeder zone. The magma ascent probably occurred due to ring-diking. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
Magnetic fabric and rock magnetism studies were performed on 25 unmetamorphosed mafic dikes of the Meso-Late Proterozoic (similar to 1.02 Ga) dike swarm from Salvador (Bahia State, NE Brazil). This area lies in the north-eastern part of the Sao Francisco Craton, which was dominantly formed/reworked during the Transamazonian orogeny (2.14-1.94 Ga). The dikes crop out along the beaches and in quarries around Salvador city, and cut across both amphibolite dikes and granulites. Their widths range from a few centimeters up to 30 m with an average of similar to 4 m, and show two main trends N 140-190 and N 100-120 with vertical dips. Magnetic fabrics were determined using both anisotropy of low-field magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM). The magnetic mineralogy was investigated by many experiments including remanent magnetization measurements at variable low temperatures (10-300 K), Mossbauer spectroscopy, high temperature magnetization curves (25-700 degrees C) and scanning electron microscopy (SEM). The rock magnetism study suggests pseudo-single-domain magnetite grains carrying the bulk magnetic susceptibility and AARM fabrics. The magnetite grains found in these dikes are large and we discard the presence of single-domain grains. Its composition is close to stoichiometric with low Ti substitution, and its Verwey transition occurs around 120 K. The main AMS fabric recognized in the swarm is so-called normal, in which the K(max)-K(int) plane is parallel to the dike plane and the magnetic foliation pole K(min)) is perpendicular to it. This fabric is interpreted as due to magma flow, and analysis of the K m inclination permitted to infer that approximately 80% of the dikes were fed by horizontal or sub-horizontal flows (K(max) < 30 degrees). This interpretation is supported by structural field evidence found in five dikes. In addition, based on the plunge of K(max), two mantle sources could be inferred; one of them which fed about 80% of the swarm would be located in the southern part of the region, and the other underlied the Valeria quarry. However, for all dikes the AARM tensors are not coaxial with AMS fabrics and show a magnetic lineation (AARM(max)) oriented to N30-60E, suggesting that magnetite grains were rotated clockwise from dike plane. The orientation of AARM lineation is similar to the orientation of a system of faults in which the Salvador normal fault is the most important. These faults were formed during Cretaceous rifting in the Reconcavo-Tucano-jatoba assemblage that corresponds to an aborted intra-continental rift formed during the opening of the South Atlantic. Therefore, the AARM fabric found for the Salvador dikes is probably tectonic in origin and suggests that the dike swarm was affected by the important tectonic event responsible for the break-up of the Gondwanaland. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
Comfort and Remus [W.W. Comfort, D. Remus, Abelian torsion groups with a pseudo-compact group topology, Forum Math. 6 (3) (1994) 323-337] characterized algebraically the Abelian torsion groups that admit a pseudocompact group topology using the Ulm-Kaplansky invariants. We show, under a condition weaker than the Generalized Continuum Hypothesis, that an Abelian torsion group (of any cardinality) admits a pseudocompact group topology if and only if it admits a countably compact group topology. Dikranjan and Tkachenko [D. Dikranjan. M. Tkachenko, Algebraic structure of small countably compact Abelian groups, Forum Math. 15 (6) (2003) 811-837], and Dikranjan and Shakhmatov [D. Dikranjan. D. Shakhmatov, Forcing hereditarily separable compact-like group topologies on Abelian groups, Topology Appl. 151 (1-3) (2005) 2-54] showed this equivalence for groups of cardinality not greater than 2(c). We also show, from the existence of a selective ultrafilter, that there are countably compact groups without non-trivial convergent sequences of cardinality kappa(omega), for any infinite cardinal kappa. In particular, it is consistent that for every cardinal kappa there are countably compact groups without non-trivial convergent sequences whose weight lambda has countable cofinality and lambda > kappa. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
XACb0070 is an uncharacterized protein coded by the two large plasmids isolated from Xanthomonas axonopodis pv. cirri, the agent of citrus canker and responsible for important economical losses in citrus world production. XACb0070 presents sequence homology only with other hypothetical proteins belonging to plant pathogens, none of which have their structure determined. The NMR-derived solution structure reveals this protein is a homodimer in which each monomer presents two domains with different structural and dynamic properties: a folded N-terminal domain with beta alpha alpha topology which mediates dimerization and a long disordered C-terminal tail. The folded domain shows high structural similarity to the ribbon-helix-helix transcriptional repressors, a family of DNA-binding proteins of conserved 3D fold but low sequence homology: indeed XACb0070 binds DNA. Primary sequence and fold comparison of XACb0070 with other proteins of the ribbon-helix-helix family together with examination of the genes in the vicinity of xacb0070 suggest the protein might be the component of a toxin-antitoxin system. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
Most approaches to Duffy’s work have been a feminist reading of poetry, focusing on the portrayal of women within the theoretical framework of feminism. However, little attention has been paid to the religious elements in Duffy’s work, something that Duffy herself has recognized. This essay will therefore focus on the centrality of religion in Duffy’s work, and will argue that her poems constitute an arena where religion is redefined and female experience and theology are reconciled. The poems under focus, “Delilah”, “Salome”, “Pilate’s wife”, “Pope Joan”, “Mrs Lazarous” and “Queen Herod” are examined in two separate sections: their portrayal of love and sexuality, and their portrayal of motherhood respectively, within the theoretical framework of feminist theology.
Resumo:
This special issue of Nordic Journal of English Studies is devoted to the research in Irish Studies being carried out in Scandinavia by a group of scholars based in Denmark, Norway and Sweden, as well as scholars associated—in one way or another—with Scandinavia. Denmark is represented by the University of Aalborg; Norway, by scholars affiliated to the Universities of Agder, the Artic University of Norway, Bergen, and Stavanger; and Sweden is represented by scholars from the universities of Dalarna, Göteborg, Stockholm, Södertörn and Umeå. Included also in this special issue is the work of two former students, who completed their Masters’ degree in Irish literature at DUCIS (Dalarna University Centre for Irish Studies), Sweden—from Norway and China respectively. The collection also contains an article by Dara Waldron, Limerick Institute of Technology, Ireland, whof recently presented his research at the Higher Seminar in Dalarna. Contributions by the Irish poet, Mary O’Donnell, who participated in the Nordic Irish Studies Network (NISN) conference, hosted by DUCIS in December 2012, are also included.
Resumo:
Abstract This article addresses the theme of place in the poetry of W. B. Yeats and Patrick Kavanagh, focusing on the concept of place as a physical and psychological entity. The article explores place as a creative force in the work of these two poets, in relation to the act of writing. Seamus Heaney, in his essay “The Sense of Place,” talks about the “history of our sensibilities” that looks to the stable element of the land for continuity: “We are dwellers, we are namers, we are lovers, we make homes and search for our histories” (Heaney 1980: 148-9). Thus, in a physical sense, place is understood as a site in which identity is located and defined, but in a metaphysical sense, place is also an imaginative space that maps the landscapes of the mind. This article compares the different ways in which Yeats and Kavanagh relate to their place of writing, physically and artistically, where place is understood as a physical lived space, and as a liberating site for an exploration of poetic voice, where the poet creates his own country of the mind.
Resumo:
This special issue of Nordic Journal of English Studies is devoted to the research in Irish Studies being carried out in Scandinavia by a group of scholars based in Denmark, Norway and Sweden, as well as scholars associated—in one way or another—with Scandinavia. Denmark is represented by the University of Aalborg; Norway, by scholars affiliated to the Universities of Agder, the Artic University of Norway, Bergen, and Stavanger; and Sweden is represented by scholars from the universities of Dalarna, Göteborg, Stockholm, Södertörn and Umeå. Included also in this special issue is the work of two former students, who completed their Masters’ degree in Irish literature at DUCIS (Dalarna University Centre for Irish Studies), Sweden—from Norway and China respectively. The collection also contains an article by Dara Waldron, Limerick Institute of Technology, Ireland, whof recently presented his research at the Higher Seminar in Dalarna. Contributions by the Irish poet, Mary O’Donnell, who participated in the Nordic Irish Studies Network (NISN) conference, hosted by DUCIS in December 2012, are also included.
Resumo:
This article addresses the theme of place in the poetry of W. B. Yeats and Patrick Kavanagh, focusing on the concept of place as a physical and psychological entity. The article explores place as a creative force in the work of these two poets, in relation to the act of writing. Seamus Heaney, in his essay “The Sense of Place,” talks about the “history of our sensibilities” that looks to the stable element of the land for continuity: “We are dwellers, we are namers, we are lovers, we make homes and search for our histories” (Heaney 1980: 148-9). Thus, in a physical sense, place is understood as a site in which identity is located and defined, but in a metaphysical sense, place is also an imaginative space that maps the landscapes of the mind. This article compares the different ways in which Yeats and Kavanagh relate to their place of writing, physically and artistically, where place is understood as a physical lived space, and as a liberating site for an exploration of poetic voice, where the poet creates his own country of the mind.