A model for vortex formation in magnetic nanodots

We use Monte Carlo simulation to study the vortex nucleation on magnetic nanodots at low temperature. In our simulations, we have considered a simple microscopic two-dimensional anisotropic Heisenberg model with term to describe the anisotropy due to the presence of the nanodot edge. We have considered the thickness of the edge, which was not considered in previous works, introducing a term that controls the energy associated to the edge. Our results clearly show that the thickness of the edge has a considerable influence in the vortex nucleation on magnetic nanodots. We have obtained the hysteresis curve for several values of the surface anisotropy and skin depth parameter ($\xi$). The results are in excellent agreement with experimental data

Constructive spherical codes on layers of flat tori

A new class of spherical codes is constructed by selecting a finite subset of flat tori from a foliation of the unit sphere S^{2L-1} of R^{2L} and designing a structured codebook on each torus layer. The resulting spherical code can be the image of a lattice restricted to a specific hyperbox in R^L in each layer. Group structure and homogeneity, useful for efficient storage and decoding, are inherited from the underlying lattice codebook. A systematic method for constructing such codes are presented and, as an example, the Leech lattice is used to construct a spherical code in R^{48}. Upper and lower bounds on the performance, the asymptotic packing density and a method for decoding are derived.Comment: 9 pages, 5 figures, submitted to IEEE Transactions on Information Theor

Knowledge and attitude towards the gradual reduction of salt in bread – an online survey

Aim: Assess knowledge and attitude towards the gradual reduction of salt in bread and the potential impact on eating habits of children (6-18 years) and their families, as part as a Health Impact Assessment pilot study.N/

Generalized Schmidt decomposition and classification of three-quantum-bit states

We prove for any pure three-quantum-bit state the existence of local bases which allow to build a set of five orthogonal product states in terms of which the state can be written in a unique form. This leads to a canonical form which generalizes the two-quantum-bit Schmidt decomposition. It is uniquely characterized by the five entanglement parameters. It leads to a complete classification of the three-quantum-bit states. It shows that the right outcome of an adequate local measurement always erases all entanglement between the other two parties.Comment: 4 pages, Revtex. Published version, minor changes and new references adde

Tools for online collaboration: Do they contribute to improve teamwork?

In the last decades, the fast growth of Information and Communication Technologies changed our way to communicate and share information. Traditional groups or teams frequently give way to virtual teams, working with tools for online collaboration. Interaction between persons geographically dispersed has become easier. However, the use of new collaboration tools can also bring many challenges. Some technologies, like e-mail, can create delays on reply or even misunderstandings, case the message is not well understood by the recipient. Can these new technologies improve the productivity and enhance the creativity between group members, improving also their confidence and motivation? Although virtual teams have a high capacity to adapt to constant market changes, personal interactions are still important, mainly to clarify tasks and goals. The main purpose of this study is to understand how tools for online collaboration may improve the productivity (and enhance creativity) in teamwork. This study was conducted through an internet platform and the survey was hosted online by SurveyMonkey.com. We intended to verify, among other questions, what users think about different collaboration tools, how often they use these tools, and how they perceive these technologies as adequate ways to communicate, to work with, and to improve productivity. Findings show that e-mail is the most used tool, and personal contact is still more important for teamwork than any tools for online collaboration. Our results contribute to perceive in what extent collaboration tools are indeed an asset or a barrier in teamwork.info:eu-repo/semantics/publishedVersio