Linguagem/discurso como outra dimensão da perspectiva ctsa no ensino das ciências/geociências : ensaiando algumas relações possíveis

A dimensão da linguagem/discurso faz parte de estudos sobre ciência que relacionam ciência, tecnologia e sociedade, apontando para a necessidade da consideração tanto da materialidade da linguagem (sistemas significantes) quanto da sua relação com o contexto histórico-social de sua produção e com as relações entre os sujeitos. Esboçamos uma possível base teórico-metodológica para a construção de abordagens CTSA-discursivas, analisando a concepção de linguagem presente nesses estudos. Apresentamos três casos em que se aplicam elementos dessa base teórica envolvendo a análise de textos (escritos e audiovisuais) da mídia jornalística e de uma atividade em sala de aula envolvendo a linguagem cartográfica. Apontamos a construção discursiva dos sujeitos/atores, a não-neutralidade das produções textuais e o deslocamento para a noção de textualização

Avaliação emergética do sistema de produção integrado de grãos, suínos e peixes em Santa Catarina: seus subsistemas e a intensificação da suínocultura.

Nesta avaliação emergética calculou-se os indicadores de transformidade solar (Tr), renovabilidade (%R), relação do rendimento de emergia (EYR), índice de investimento de emergia (EIR), relação de carga ambiental (ELR) e a relação de troca de emergia (EER) para avaliar os aspectos ambientais do sistema de produção integrado de grãos, suínos e peixes (SPIGSP) em pequenas propriedades rurais do estado de Santa Catarina. Estes resultados foram comparados com os obtidos para os subsistemas (grãos, suínos e peixes) que compõe o sistema integrado trabalhando de forma independente. Alem disso, foi calculado como os indicadores emergéticos do SPIGSP são alterados com intensificação da suinocultura

Electron refraction at lateral atomic interfaces

We present theoretical simulations of electron refraction at the lateral atomic interface between a “homogeneous” Cu(111) surface and the “nanostructured” one-monolayer (ML) Ag/Cu(111) dislocation lattice. Calculations are performed for electron binding energies barely below the 1 ML Ag/ Cu(111) M-point gap (binding energy EB ¼53 meV, below the Fermi level) and slightly above its C -point energy (EB ¼160 meV), both characterized by isotropic/circular constant energy surfaces. Using plane-wave-expansion and boundary-element methods, we show that electron refraction occurs at the interface, the Snell law is obeyed, and a total internal reflection occurs beyond the critical angle. Additionally, a weak negative refraction is observed for EB ¼53 meV electron energy at beam incidence higher than the critical angle. Such an interesting observation stems from the interface phase-matching and momentum conservation with the umklapp bands at the second Brillouin zone of the dislocation lattice. The present analysis is not restricted to our Cu-Ag/Cu model system but can be readily extended to technologically relevant interfaces with spinpolarized, highly featured, and anisotropic constant energy contours, such as those characteristic for Rashba systems and topological insulators. Published by AIP Publishing.Peer ReviewedPostprint (published version

A COVID-19-based modified epidemiological model and technological approaches to help vulnerable individuals emerge from the lockdown in the UK

COVID-19 has shown a relatively low case fatality rate in young healthy individuals, with the majority of this group being asymptomatic or having mild symptoms. However, the severity of the disease among the elderly as well as in individuals with underlying health conditions has caused significant mortality rates worldwide. Understanding this variance amongst different sectors of society and modelling this will enable the different levels of risk to be determined to enable strategies to be applied to different groups. Long-established compartmental epidemiological models like SIR and SEIR do not account for the variability encountered in the severity of the SARS-CoV-2 disease across different population groups. The objective of this study is to investigate how a reduction in the exposure of vulnerable individuals to COVID-19 can minimise the number of deaths caused by the disease, using the UK as a case study. To overcome the limitation of long-established compartmental epidemiological models, it is proposed that a modified model, namely SEIR-v, through which the population is separated into two groups regarding their vulnerability to SARS-CoV-2 is applied. This enables the analysis of the spread of the epidemic when different contention measures are applied to different groups in society regarding their vulnerability to the disease. A Monte Carlo simulation (100,000 runs) along the proposed SEIR-v model is used to study the number of deaths which could be avoided as a function of the decrease in the exposure of vulnerable individuals to the disease. The results indicate a large number of deaths could be avoided by a slight realistic decrease in the exposure of vulnerable groups to the disease. The mean values across the simulations indicate 3681 and 7460 lives could be saved when such exposure is reduced by 10% and 20% respectively. From the encouraging results of the modelling a number of mechanisms are proposed to limit the exposure of vulnerable individuals to the disease. One option could be the provision of a wristband to vulnerable people and those without a smartphone and contact-tracing app, filling the gap created by systems relying on smartphone apps only. By combining very dense contact tracing data from smartphone apps and wristband signals with information about infection status and symptoms, vulnerable people can be protected and kept safer

Análise emergética dos sistemas de pesca no pantanal

Os sistemas de pesca (profissional-artesanal, subsistência e amadora) constituem atividades econômicas muito importantes no Pantanal. Por meio da análise emergética será avaliado seu desempenho. As primeiras análises revelam que a pesca profissional artesanal utiliza amplamente os recursos naturais, com pouca entrada de recursos econômicos externos, e o peixe é vendido para turistas e comunidade local; os fluxos são internos ao ecossistema e as externalidades são mínimas. A pesca de subsistência mostra ser auto-suficiente. A pesca amadora, por outro lado, requer maior infra-estrutura, as articulações com a economia local são limitadas e gera vários tipos de externalidades negativas. In the “Pantanal”, a very big Brazilian wetland, fishery is an important economic activity that is carried out under three modalities: professional-artisanal, subsistence and touristic. Their ecological and thermodynamic performance will be studied using the emergy methodology. As first stage of this analysis, it was realized an information recovery in order to prepare the systems diagrams. The diagrams revealed the dependence of each one of fishery systems with local and external resources. Subsistence fishery is sustainable but doesn’t have product for sale. Professional-artisanal fishery interacts with different markets and uses a small quantity of external inputs. Touristic fishery depends on infra-structure investments and do not interact in adequate form with local economy

Trigonometry of 'complex Hermitian' type homogeneous symmetric spaces

This paper contains a thorough study of the trigonometry of the homogeneous symmetric spaces in the Cayley-Klein-Dickson family of spaces of 'complex Hermitian' type and rank-one. The complex Hermitian elliptic CP^N and hyperbolic CH^N spaces, their analogues with indefinite Hermitian metric and some non-compact symmetric spaces associated to SL(N+1,R) are the generic members in this family. The method encapsulates trigonometry for this whole family of spaces into a single "basic trigonometric group equation", and has 'universality' and '(self)-duality' as its distinctive traits. All previously known results on the trigonometry of CP^N and CH^N follow as particular cases of our general equations. The physical Quantum Space of States of any quantum system belongs, as the complex Hermitian space member, to this parametrised family; hence its trigonometry appears as a rather particular case of the equations we obtain.Comment: 46 pages, LaTe

Linguagem/discurso como outra dimensão da perspectiva ctsa no ensino das ciências/geociências : ensaiando algumas relações possíveis

A dimensão da linguagem/discurso faz parte de estudos sobre ciência que relacionam ciência, tecnologia e sociedade, apontando para a necessidade da consideração tanto da materialidade da linguagem (sistemas significantes) quanto da sua relação com o contexto histórico-social de sua produção e com as relações entre os sujeitos. Esboçamos uma possível base teórico-metodológica para a construção de abordagens CTSA-discursivas, analisando a concepção de linguagem presente nesses estudos. Apresentamos três casos em que se aplicam elementos dessa base teórica envolvendo a análise de textos (escritos e audiovisuais) da mídia jornalística e de uma atividade em sala de aula envolvendo a linguagem cartográfica. Apontamos a construção discursiva dos sujeitos/atores, a não-neutralidade das produções textuais e o deslocamento para a noção de textualização

A Framework for Generalising the Newton Method and Other Iterative Methods from Euclidean Space to Manifolds

The Newton iteration is a popular method for minimising a cost function on Euclidean space. Various generalisations to cost functions defined on manifolds appear in the literature. In each case, the convergence rate of the generalised Newton iteration needed establishing from first principles. The present paper presents a framework for generalising iterative methods from Euclidean space to manifolds that ensures local convergence rates are preserved. It applies to any (memoryless) iterative method computing a coordinate independent property of a function (such as a zero or a local minimum). All possible Newton methods on manifolds are believed to come under this framework. Changes of coordinates, and not any Riemannian structure, are shown to play a natural role in lifting the Newton method to a manifold. The framework also gives new insight into the design of Newton methods in general.Comment: 36 page