Detrital zircon from a late Paleozoic accretionary complex of SW Iberia (Variscan Belt): History of crustal growth and recycling at the Rheic convergent margin

In this study we present new U-Pb ages of detrital zircons from greywackes and quartzites of the Pulo do Lobo Anticline (PLA) that have been interpreted to represent a Late Paleozoic accretionary complex in SW Iberia. The PLA separates the Ossa Morena Zone, which has a North- Gondwana affinity throughout Late Ediacaran and Early Paleozoic times, from the South Portuguese Zone, which is considered to be underlain by Laurussia basement. The PLA stratigraphy most likely represents a synorogenic basin that records the closure of the Late Paleozoic Rheic Ocean and the amalgamation of Pangaea. The youngest formations of the PLA contain upper Devonian microfossils.The results obtained indicate that the detrital zircons from the PLA represent a wide range of Precambrian and Paleozoic crystallization ages. Recycling of older sedimentary units of the Late Ediacaran active margin (Cadomian/Pan-African orogenies) as well as of the Early Paleozoic rifting and passive margin (Rheic Ocean) stages, accounts for the older populations with North-Gondwana affinity (Cambrian, Neoproterozoic, Paleoproterozoic and Archean, with a gap of Mesoproterozoic-age). However, the Mesoproterozoic detrital zircon ages found in the greywackes of the Pulo do Lobo Formation (< 7%) that do not correspond to any substantial source within North-Gondwana, could come from recycled sedimentary deposits or from denudation of Grenville-age basement (Laurussia?). The more recent formations present in the northern limb (Ferreira-Ficalho Group) of the PLA show a significant age cluster in the upper Devonian (c. 378 Ma), whereas on the southern limb (Chança Group), samples have from base to top of the stratigraphic sequence: a minor age cluster in the middle Devonian (c. 390 Ma), a significant age cluster in upper Devonian (c. 380 Ma) and very significant age cluster in the upper Devonian (c. 372 Ma). The presence of middle-upper Devonian detrital zircons in combination with very low abundances of Mesoproterozoic detrital zircon suggests that the PLA sedimentary rocks were not derived from exotic sources but rather have a North-Gondwanan origin. The zircon population in the interval c. 390-380 Ma has no identified corresponding magmatic or stratigraphic source in SW Iberia. Considering that, during the development of the upper Devonian basins of SW Iberia, Laurussia basement was not exposed and that there was no magmatic arc on the North-Gondwana margin, we suggest that the c. 390- 380 Ma detrital zircons are most probably derived from denudation of a (intra-oceanic) magmatic arc related to the closure of the Rheic Ocean

How hole defects modify vortex dynamics in ferromagnetic nanodisks

Defects introduced in ferromagnetic nanodisks may deeply affect the structure and dynamics of stable vortex-like magnetization. Here, analytical techniques are used for studying, among other dynamical aspects, how a small cylindrical cavity modify the oscillatory modes of the vortex. For instance, we have realized that if the vortex is nucleated out from the hole its gyrotropic frequencies are shifted below. Modifications become even more pronounced when the vortex core is partially or completely captured by the hole. In these cases, the gyrovector can be partially or completely suppressed, so that the associated frequencies increase considerably, say, from some times to several powers. Possible relevance of our results for understanding other aspects of vortex dynamics in the presence of cavities and/or structural defects are also discussed.Comment: 9 pages, 4 page

User acceptance of open enterprise solution: the OSS-ERP case

Organizations implement Enterprise Resource Planning (ERP) systems with the objective of reaching operational efficiency and the incorporation to new markets through the information flow control on time of the entire organization. However, ERP systems are complex tools, mainly for the small and medium size enterprises (SMEs). For these reason, new ERP configurations have arisen for SMEs such as Open Source Software-ERP (OSS-ERP). OSS-ERP is a research topic barely analyzed by the literature. Specifically, this paper’s aim is to focus on the OSS-ERP users’ acceptance and use. The authors have developed a research model based on the Technology Acceptance Model (TAM) for testing the users’ behavior toward OSS-ERP.Las organizaciones implantan Sistemas Integrados de Gestión (ERP, acrónimo de Enterprise Resource Planning) con el objetivo de alcanzar eficiencias operativas y la incorporación a nuevos mercados mediante un mayor control del flujo de información de toda la empresa a tiempo real. Sin embargo, los sistemas ERP son herramientas complejas, principalmente la pequeña y mediana empresa (PYME). Por esta razón, están surgiendo nuevas configuraciones de sistemas ERP para PYME como los sistemas ERP de código abierto (OSS-ERP). OSS-ERP es un tópico de investigación escasamente analizado en la literatura. Concretamente, este artículo se centra en el y aceptación de los usuarios a los sistemas OSS-ERP. Los autores han desarrollado un modelo de investigación basado en Metamodelo de Aceptación de la Tecnología (TAM) para testar el comportamiento de los usuarios hacia los sistemas OSS-ERP

Effective lagrangian for a mass dimension one fermionic field in curved spacetime

In this work we use momentum-space techniques to evaluate the propagator $G(x,x^{\prime})$ for a spin $1/2$ mass dimension one spinor field on a curved Friedmann-Robertson-Walker spacetime. As a consequence, we built the one-loop correction to the effective lagrangian in the coincidence limit. Going further we compute the effective lagrangian in the finite temperature regime. We arrive at interesting cosmological consequences, as time-dependent cosmological `constant', fully explaining the functional form of previous cosmological models.Comment: 9 pages, 0 figure

Effect of user experience on technology acceptance: the case of foss

Free and open source software (FOSS) movement essentially arises like answer to the evolution occurred in the market from the software, characterized by the closing of the source code. Furthermore, some FOSS characteristics, such as (1) the advance of this movement and (2) the attractiveness that contributes the voluntary and cooperative work, have increased the interest of the users towards free software. Traditionally, research in FOSS has focused on identifying individual personal motives for participating in the development of a FOSS project, analyzing specific FOSS solutions, or the FOSS movement itself. Nevertheless, the advantages of the FOSS for users and the effect of the demographic dimensions on user acceptance for FOSS have been two research topics with little attention. Specifically, this paper’s aim is to focus on the influence of the user experience with FOSS the FOSS acceptance. Based on the literature, user experience is an essential demographic dimension for explaining the Information Systems acceptance. With this purpose, the authors have developed a research model based on the Technological Acceptance Model (TAM).El movimiento asociado al software de código abierto (FOSS) surge como una respuesta a la evolución acontecida en el mercado del software, caracterizado por el cierre del código fuente. Además, algunas características del FOSS como (1) el avance de este movimiento y (2) el atractivo que suscita debido a que se construye bajo la filosofía de trabajo voluntario y cooperativo, ha incrementado el interés de los usuarios hacia FOSS. Tradicionalmente las investigaciones en FOSS han estado centradas en identificar las motivaciones personales de participar en el desarrollo de un proyecto FOSS. Mientras que las ventajas del FOSS para los usuarios y el efecto de las dimensiones demográficas en la aceptación de FOSS han sido dos tópicos de investigación con poca atención. Concretamente, este artículo se centra en analizar la influencia de la experiencia con FOSS en la propia aceptación de FOSS. Basado en la literatura, la experiencia del usuario es una dimensión demográfica esencial para explicar la aceptación de los Sistemas de Información. Con este propósito, los autores han desarrollado un modelo de investigación basado en el Metamodelo de Aceptación de la Tecnología (TAM)