Discretization-dependent model for weakly connected excitable media

Pattern formation has been widely observed in extended chemical and biological processes. Although the biochemical systems are highly heterogeneous, homogenized continuum approaches formed by partial differential equations have been employed frequently. Such approaches are usually justified by the difference of scales between the heterogeneities and the characteristic spatial size of the patterns. Under different conditions, for example, under weak coupling, discrete models are more adequate. However, discrete models may be less manageable, for instance, in terms of numerical implementation and mesh generation, than the associated continuum models. Here we study a model to approach discreteness which permits the computer implementation on general unstructured meshes. The model is cast as a partial differential equation but with a parameter that depends not only on heterogeneities sizes, as in the case of quasicontinuum models, but also on the discretization mesh. Therefore, we refer to it as a discretization-dependent model. We validate the approach in a generic excitable media that simulates three different phenomena: the propagation of action membrane potential in cardiac tissue, in myelinated axons of neurons, and concentration waves in chemical microemulsions.We acknowledge the support from CAPES, grant 88881.065002/2014-01 of the Brazilian program Science without borders, FAPEMIG, CNPq, UFJF, and from MINECO of Spain under the Ramon y Cajal program, grant number RYC-2012-11265Peer ReviewedPostprint (published version

Enhancing creativity through Biological Stimuli during new products ideation

The development of new and innovative products consists in a competitive advantage, allowing companies to overcome competitors, maintain or even increase its market share. As the product development cycle is shortening, a greater effort is required at the ideation of new technologies and products. In this context, the bio-inspired design has been receiving attention as a creativity strengthening method. However, the majority of methods and tools proposed in this field present biological stimuli in the form of literature extracts, requiring a great cognitive effort from the design teams in abstracting principles to generate ideas. In this paper a systematic approach to biological stimuli development is presented, as well as its contribution during the ideation process. An experiment was conducted on the context of a product design course. As result, it was evidenced that the biological stimulators contributed to the increase of the ideas\u27 utility and variety, favoring the innovation process

Adequação dos exames de radiologia solicitados por um departamento de emergência: um estudo retrospetivo

Imaging tests are essential for diagnosis in the emergency context and convey clinical information that is essential to assess the appropriateness of the tests and improve their interpretation. Therefore, we aimed to analyze the imaging tests requested by the Emergency Department in a district hospital.info:eu-repo/semantics/publishedVersio

Pólen estocado nos ninhos de abelhas dos gêneros Partamona, Scaura e Trigona (Hymenoptera, Apidae)

Bees and angiosperms established a mutualistic relationship along the evolutionary time. The aim of this study is to contribute for the understanding of this relation analyzing pollen stored by stingless bees colonies distributed along the Rio Negro. Fourteen species of Meliponini from the genera Partamona, Scaura, and Trigona were studied with regard to the content of pollen pots. The pollen material was removed from the pollen pots, homogenized, and prepared according to the usual acetolysis technique. The overlap of the trophic niche and the grouping of species by similarity of niches was calculated. The identification revealed 78 pollen types belonging to 36 families, being 37 types attractive and 16 considered as promoters of a temporary specialization event. With the results, it was possible to indicate a list of important plants for meliponiculture in the Amazon.Abelhas e plantas estabeleceram ao longo do tempo evolutivo uma relação mutualística. Buscando contribuir para o entendimento dessa relação, foi analisado o pólen estocado por colônias de abelhas-sem-ferrão distribuídas ao longo do rio Negro. Foram estudados potes de pólen de 14 espécies de Meliponini dos gêneros Partamona, Scaura e Trigona. O material polínico foi retirado dos potes de pólen, homogeneizado e preparado segundo técnica usual de acetólise. Foram calculados a sobreposição de nicho trófico e o agrupamento das espécies pela similaridade de nichos. Foi identificado o total de 78 tipos polínicos, pertencentes a 36 famílias, sendo 37 destes, considerados atrativos, enquanto 16 foram promotores de eventos de especialização temporária. Com os resultados obtidos foi possível indicar uma lista de plantas de importância para a meliponicultura na Amazônia.361372Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Exploring the chemodynamics of metal-poor stellar populations

Metal-poor stars are key for studying the formation and evolution of the Galaxy. Evidence of the early mergers that built up the Galaxy remains in the distributions of abundances, kinematics, and orbital parameters of its stars. Several substructures resulting from these mergers have been tentatively identified in the literature. We conduct a global analysis of the chemodynamic properties of metal-poor stars. Our aim is to identify signs of accreted and in situ stars in different regions of the parameter space and to investigate their differences and similarities. We selected a sample of about 6600 metal-poor stars with [Fe/H] $\leq$ -0.8 from DR3 of the GALAH survey. We used unsupervised machine learning to separate stars in a parameter space made of two normalised orbital actions, plus [Fe/H] and [Mg/Fe], without additional a priori cuts on stellar properties. We divided the halo stars in four main groups. All groups exhibit a significant fraction of in situ contamination (ISC). Accreted stars of these groups have very similar chemical properties, except for those of the group of stars with very retrograde orbits. This points to at most two main sources of accreted stars in the current sample, the major one related to Gaia-Enceladus (GE) and the other possibly related to Thamnos and/or Sequoia. Stars of GE are r-process enriched at low metallicities, but a contribution of the s-process appears with increasing metallicity. A flat trend of [Eu/Mg] as a function of [Fe/H] suggests that only core collapse supernovae contributed to r-process elements in GE. To better characterise accreted stars in the low metallicity regime, high precision abundances and guidance from chemical evolution models are needed. It is possible that ISC in samples of accreted stars has been underestimated. This can have important consequences for attempts to estimate the properties of the original systems.Comment: 22 pages, 22 figures, Accepted for publication in A&

Linux Based Ethernet Communication for Xilinx FPGAs

This article presents the implementation of an Ethernet communication platform for use on Xilinx FPGAs. The proposed solution relies on a synthesized embedded system to provide network data transfer and control capabilities, for use with synthesizable electronic devices. Most TCP/IP stack services and protocols were implemented and the design is flexible to allow adaptation and/or expansion for different application scenarios. Currently this platform is being used on the development of a FPGA based JTAG controller, with remote access. The embedded system hardware requires a MicroBlaze softcore microprocessor running a Petalinux operating system.info:eu-repo/semantics/publishedVersio

Ray Tracing in Non-Euclidean Spaces

This dissertation describes a method for modeling, simulating and real-time rendering piecewise linear approximations of generic non-Euclidean 3D spaces. The 3D rendering pipeline most commonly used, where one multiplies each vertex coordinate by a 4x4 matrix to project it on the screen does not work for all cases where the space does not obey Euclid’s postulates (non-Euclidean space). Furthermore, while other non-Euclidean rendering tools only work for a limited type of spaces, our approach allows us to model, simulate, and render any isometrically embeddable non-Euclidean space and eventual objects lying therein. We envision at least two main applications for our approach. The first for helping mathematicians get a better understanding of what arbitrary spaces look like (e.g., hyperconical space, hyper-spherical space, and so forth). The second for assisting physicists to visualize and simulate the effects of bent space (e.g., black holes, wormholes, Alcubierre drive, and so forth) on light, and on physical objectsEsta dissertação descreve um método para modelar, simular e renderizar aproximações lineares de espaços não Euclideanos de forma genérica e em tempo real. A técnica de renderização 3D mais comum, que multiplica a matriz de projeção 4 x 4 por cada vértice para determinar as coordenadas do respetivo pixel no ecrã, nem sempre funciona quando o espaço não obedece a um postulado de Euclides (espaço não-Euclideano). Além disso, enquanto outras ferramentas para renderizar espaços não-Euclideanos só funcionam para certos tipos de espaços, a nossa técnica permite modelar, simular e renderizar qualquer espaço não-Euclideano embebível isometricamente, bem como eventuais objetos nele existentes. Antevemos pelo menos dois usos para a nossa técnica. A primeira para ajudar matemáticos a compreender melhor o aspeto de espaços arbitrários (e.g., espaço hiper-cónico, espaço hiper-esférico, etc.). A segunda para ajudar físicos a visualizar e simular os efeitos de espaço curvo (e.g., buracos negros, buracos de minhoca, deformações Alcubierra drive, etc.) em luz e objetos físicos circundantes