From vortex molecules to the Abrikosov lattice in thin mesoscopic superconducting disks

Stable vortex states are studied in large superconducting thin disks (for numerical purposes we considered with radius R = 50 \xi). Configurations containing more than 700 vortices were obtained using two different approaches: the nonlinear Ginzburg-Landau (GL) theory and the London approximation. To obtain better agreement with results from the GL theory we generalized the London theory by including the spatial variation of the order parameter following Clem's ansatz. We find that configurations calculated in the London limit are also stable within the Ginzburg-Landau theory for up to ~ 230 vortices. For large values of the vorticity (typically, L > 100), the vortices are arranged in an Abrikosov lattice in the center of the disk, which is surrounded by at least two circular shells of vortices. A Voronoi construction is used to identify the defects present in the ground state vortex configurations. Such defects cluster near the edge of the disk, but for large L also grain boundaries are found which extend up to the center of the disk.Comment: 15 pages, 10 figures, RevTex4, submitted to Phys. Rev.

Conductivity of Coulomb interacting massless Dirac particles in graphene: Regularization-dependent parameters and symmetry constraints

We compute the Coulomb correction $\mathcal{C}$ to the a. c. conductivity of interacting massless Dirac particles in graphene in the collisionless limit using the polarization tensor approach in a regularization independent framework. Arbitrary parameters stemming from differences between logarithmically divergent integrals are fixed on physical grounds exploiting only spatial $O(2)$ rotational invariance of the model which amounts to transversality of the polarization tensor. Consequently $\mathcal{C}$ is unequivocally determined to be $(19- 6\pi)/12$ within this effective model. We compare our result with explicit regularizations and discuss the origin of others results for $\mathcal{C}$ found in the literature

Tendências na aplicação de tecnologia de membranas no processamento de frutas tropicais.

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A semantic web service-based architecture for the interoperability of e-government services

We propose a semantically-enhanced architecture to address the issues of interoperability and service integration in e-government web information systems. An architecture for a life event portal based on Semantic Web Services (SWS) is described. The architecture includes loosely-coupled modules organized in three distinct layers: User Interaction, Middleware and Web Services. The Middleware provides the semantic infrastructure for ontologies and SWS. In particular a conceptual model for integrating domain knowledge (Life Event Ontology), application knowledge (E-government Ontology) and service description (Service Ontology) is defined. The model has been applied to a use case scenario in e-government and the results of a system prototype have been reported to demonstrate some relevant features of the proposed approach

Erratum: Martins, M.S., et al. Wideband and wIde beam polyvinylidene difluoride (PVDF) acoustic transducer for broadband underwater. Sensors 2019, 19, 3991

The authors wish to make the following erratum to this paper [...].info:eu-repo/semantics/publishedVersio

Rubiaceae family: Flora Argentina, history and evolution

The Rubiaceae family in Argentina is represented by 41 genera and 146 species, of which 9 spp., 2 subspp., and 1 variety are endemic. The highest concentration and endemism are found in the NE ofthe country, in savannas, rainforests, riverside forests, followed by the NW of Argentina, from sea level to 1000-4000 m in the Andes. They also inhabit the heterogeneous landscape of the Center Region of the country, and few species grow in the Patagonian zone. This work is the contribution to the integral study of the Flora of our country. The beginning of knowledge of Argentina’s vegetation dates back to the mid 19th century, with foreign naturalists attracted by the virgin vegetation of the country. The Academy of Science and the first Institute of Botany were founded in Córdoba, where the herbarium and methodical study of native plants began. The first floristic works were carried out, which were enriched in the 20th century, with the improvement of instruments, development of new methods, which changed the analysis and interpretation of data. Fast means of transportation and communication facilitated the exchange of ideas and the increase in botanical expeditions. Despite the advances in the local botany, a comprehensive work on the country’s flora was still missing. It began with species checklists, regional catalogues and flora from various provinces. At the Instituto Botánica Darwinion (IBODA), the project “Flora Argentina” began methodically with the hand-picking of species bibliography, collection and identification activities. Professor Nélida Bacigalupo began to work there in 1949. She worked for more than 60 years and her publications about Rubiaceae taxa were the first in the country. When we met her, we had the privilege of valuing her predisposition and her wisdom as “Teacher”, which led to the transfer of her knowledge to three generations, for which we express our appreciation and gratitude

ELF Teaching in Portuguese Schools: The Not-so-good Old Days Are Back

With the aim of contributing to the comprehension of the changes that have recently been observed in Portuguese EFL school curriculum, this paper is a critical analysis of curricular factors that contribute to the challenges today’s EFL teachers face in schools. The data analysed comprise the documents published by national educational authorities (EFL learning outcomes) as well as the teachers’ examination test required to enter the EFL teaching profession. The educational principles underlying these documents, as well as the teaching practices they support and encourage, are compared to the principles and the methodological recommendations of previous, more progressive, Portuguese EFL syllabi. The methodological trends identified on the current EFL teaching panorama are also contrasted with the principles of the language teachers education programs taught at Portuguese universities