Showing papers by "Universidade Federal de Santa Catarina published in 2023"

Equation of state for strange quark matter: Linking the Nambu–Jona-Lasinio model to perturbative QCD

Abstract: Neutron star constraints and {\it ab initio} pQCD evaluations require the EoS representing cold quark matter to be stiff at intermediate baryonic densities and soft at high-$n_B$. Here, I suggest that the three flavor NJL model with a density dependent repulsive coupling, $G_V(\mu)$, can generate an EoS which interpolates between these two regimes. Such an interpolation requires repulsion to start decreasing with the chemical potential just after chiral transition takes place. The conjecture behind this mechanism is that repulsion should be necessary only as long as the quark condensates, which dress the effective masses, have non-vanishing values. This assumption guarantees that an initially hard EoS suffers a conspicuous change of slope at ${\cal E} \simeq 0.7 \,{\rm GeV fm^{-3}}$ converging to the pQCD results at higher energy densities. Then, the speed of sound naturally reaches a non-conformal maximum at $n_B = 3.23 \, n_0 = 0.52 \, {\rm fm}^{-3}$ while the trace anomaly remains positive for all densities, in agreement with recent investigations. These non-trivial results {\it cannot} be simultaneously obtained when $G_V$ vanishes or has a fixed value. Therefore, the simple model proposed here is able to link the (non-perturbative) region of intermediate densities to the region where pQCD becomes reliable.

Regimes of literacy as regimes of truth about Africa: language ideologies and southern voices

Abstract: In this chapter we discuss and problematize the colonial and contemporary connections between regimes of literacy—including ideologies of writing—and regimes of truth about Africa. This means considering the process of knowledge production, dissemination and reception as politically and economically controlled, contributing to a continuous remodeling of power relations. By situating our arguments in African colonial contexts, we explore the role played by ideologies of literacy, mainly centered on the alphabetic script, in defining what counts as language—taken as fixed and named codes-, which consequently shaped the ideological beliefs about the nature of knowledge production and knowledge transmission which is carried out via extant codes. This chapter is on literacy in Africa, colonial regime of literacy, regime of truth, authorship, standpoint, politics of knowledge production, oral tradition, politics of citation and editorial politics. The bigger proposition we are making goes beyond simply identifying insights in Africa; rather, we seek to understand how such insights affected the nature of literacy in the Global Norths as well.

Duality Principles and Numerical Procedures for a Large Class of Non-convex Models in the Calculus of Variations

Abstract: This article develops duality principles and numerical results for a large class of non-convex variational models. The main results are based on fundamental tools of convex analysis, duality theory and calculus of variations. More specifically the approach is established for a class of non-convex functionals similar as those found in some models in phase transition. Finally, in the last section we present a concerning numerical example and the respective software.

Remando nas águas de Amsterdam. Fragmentos do meu diário de campo

Abstract: Neste capítulo o autor compartilha uma parte de suas experiências como pesquisador morando em Amsterdam, estudando as infraestruturas de saneamento da cidade. Também elabora algumas reflexões que são atravessadas pelos conceitos de “estrangeiro” e “diferenças”, que constantemente se fazem presentes nessa vida que começou a construir na capital neerlandesa, para pensar na provocação que esse livro faz sobre uma etnografia além-mar.

On Duality Principles and Related Convex Dual Formulations Suitable for Local and Global Non-Convex Variational Optimization

Abstract: This article develops duality principles and related convex dual formulations suitable for the local and global optimization of non-convex primal formulations for a large class of models in physics and engineering. The results are based on standard tools of functional analysis, calculus of variations and duality theory. In particular, we develop applications to a Ginzburg-Landau type equation.

Approximate Numerical Procedures for the Navier-Stokes System Through the Generalized Method of Lines

Abstract: This article develops applications of the generalized method of lines to numerical solutions of the time-independent, incompressible Navier-Stokes system in fluid mechanics. We recall that for such a method, the domain of the partial differential equation in question is discretized in lines (or more generally in curves), and the concerning solutions are written on these lines as functions of the boundary conditions and the domain boundary shape.

Approximate Numerical Procedures for the Navier-Stokes System Through the Generalized Method of Lines

Abstract: This article develops applications of the generalized method of lines to numerical solutions of the time-independent, incompressible Navier-Stokes system in fluid mechanics. We recall that for such a method, the domain of the partial differential equation in question is discretized in lines (or more generally in curves), and the concerning solutions are written on these lines as functions of the boundary conditions and the domain boundary shape.

Duality Principles and Numerical Procedures for a Large Class of Non-convex Models in the Calculus of Variations

Abstract: This article develops duality principles and numerical results for a large class of non-convex variational models. The main results are based on fundamental tools of convex analysis, duality theory and calculus of variations. More specifically the approach is established for a class of non-convex functionals similar as those found in some models in phase transition. Finally, in the last section we present a concerning numerical example and the respective software.

Geological and climatic controls of low flows in Brazil

Abstract: Low flows are generated by the interplay of climatic variability and basin water storage dynamics, which depend on basin attributes such as geology and soil properties. Even though low flows have been predicted worldwide, their controls and generation mechanisms remain elusive in many regions, such as South America. Here, we investigate the relative importance of climate and basin attributes in the spatial variability of minimum annual 7-day streamflow magnitudes (Qmin) of 1412 river basins in Brazil. We analyze time series of observed daily streamflow, precipitation and evaporation from 1980-2020; geology such as rock type and hydraulic conductivity; topography; soil properties such as sand content and class; and land cover. We estimate Qmin with a simple conceptual model that separates the roles of climate and basin attributes in regulating low flows. For each river basin, we identify the longest annual dry spells and estimate Qmin using an exponential decay model with three components: (i) initial flow, which indicates the basin’s water storage at the dry spell onset; (ii) dry spell length (Tdry), representing climate seasonality, computed from a 31-day precipitation minus evaporation series; and (iii) flow recession rate (Qrec), indicating how quickly the basin releases the water stored. We estimate the initial flow component with the fraction (β) of mean annual precipitation minus evaporation (PEm) that recharges the aquifer. This fraction is estimated from basin attributes using model-based recursive partitioning, a method similar to regression trees, in which we found soil properties as the predominant attributes. The flow recession component is estimated likewise, in which we found rock type and composition as the predominant attributes. We found that the model explains 56% of the variance in observed Qmin. The large-scale patterns show a close match. Results show that the relative importance of climate and basin attributes depends on the spatial scale of analysis. Climate and basin attributes are similarly important at the national scale, in which changing PEm, Tdry, Qrec, and β by one spatial standard deviation change estimated Qmin on average by 41%, 57%, 66%, and 31% respectively. On the other hand, basin attributes control low flow variability on subnational scales. Analyzing blocks sized 300 by 300 km, changing PEm, Tdry, Qrec, and β by one spatial standard deviation in each block change estimated Qmin on average by 19%, 11%, 36%, and 19%. Our interpretation is that the spatial variability of low flows is regulated mainly by the basin’s water storage capacity, here driven by rock type and composition, which even compensates for the highly seasonal climate from the South American monsoons. For example, most of the highest low flows (i.e., Qmin above 1 mm/d) are located in high-storage sandstone aquifers, a common aquifer type in Brazil. These highest low flows rarely occur in low-storage aquifers, which require a combination of high annual precipitation (i.e., above 3000 mm/yr) and the absence of a dry season such as in northwestern Amazonia. These findings can contribute to water security by estimating the impacts of climate change and variability on droughts.

Becoming a wandering body: education and body in tim ingold's thought

Abstract: ABSTRACT: The article deals with the place of the body and education in the thought of Scottish anthropologist Timothy Ingold. We present the author's main metatheoretical assumptions, highlighting those central to our argument: the pairs nature-culture, body-mind, and animality-humanity. Ingold's thought is a wager on a human education based on becoming, understood as a singular insertion in a tradition always situated on historicity and immanence. It does not have a pre-defined direction but rather establishes itself through wandering, starting from a relationship of attention and perception of the world mediated by others who are already present in it. The body is conceived as a constitutive dimension of the human being, without which it is impossible to understand the way of being-with-others in the world. Thus, human potential is realized, and attention and perception are crucial. By problematizing the consequences of this thought for human education and body education, we found powerful conceptual tools to criticize the modern tradition of education, as well as to envision another way of conceiving human and body education, which are not understood as a transmission of the knowledge with which one operates logically, nor as the education of a material body that should perform as much as possible. Contrarywise, it is conceived as the transmission of a singular form of perception and (re) creation of the world and as an instance of creating paths wandering, respectively.

Approximate Numerical Procedures for the Navier-Stokes System Through the Generalized Method of Lines

Abstract: This article develops applications of the generalized method of lines to numerical solutions of the time-independent, incompressible Navier-Stokes system in fluid mechanics. We recall that for such a method, the domain of the partial differential equation in question is discretized in lines (or more generally in curves), and the concerning solutions are written on these lines as functions of the boundary conditions and the domain boundary shape.

Variabilidade da frequência cardíaca e tolerância ao exercício físico na doença pulmonar obstrutiva crônica

Abstract: Alterações ventilatórias e cardiovasculares podem ser observadas em pacientes com Doença Pulmonar Obstrutiva Crônica. A adequada interação entre a biomecânica ventilatória e o sistema cardiovascular interfere no controle autonômico desses pacientes e essa interação pode ser verificada através da variabilidade da frequência cardíaca. A intolerância ao exercício está diretamente relacionada à qualidade de vida e prognóstico do paciente DPOC, a alteração simpática parece limitar essa tolerância, dessa forma o objetivo geral desse trabalho, foi revisar a influência da disfunção autonômica na tolerância ao exercício no indivíduo com Doença Pulmonar Obstrutiva Crônica. Tratou-se de um estudo de revisão de literatura de abordagem narrativa. A busca da literatura foi realizada nas bases de dados PubMed e Lilacs, sem restrições de data e idiomas. Foram identificados na base de dados PubMed 188 artigos e na base de dados Lilacs 65 artigos, após a remoção de duplicatas tivemos o total de 178 artigos, ao final da seleção 15 artigos foram incluídos para a análise qualitativa. A capacidade ao exercício é afetada devido as alterações da variabilidade da frequência cardíaca, e os pacientes DPOC apresentam níveis significativamente mais baixos de VFC, tanto de fatores simpáticos quanto parassimpáticos. Porém, a influência destes fatores na tolerância ao exercício ainda não estão bem elucidadas e podem representar um marcador prognóstico útil e preciso no avanço e prevenção da doença, assim como na tolerância ao exercício físico nesses indivíduos.

Apresentação

Abstract: Apresentação - v.19, n.4, 2022

Ketogenic diets, exercise performance, and training adaptations

Abstract: The ketogenic diet has been proposed as a nutritional strategy in sports. This review was undertaken to provide an overview of the recent literature concerning the effects of ketogenic diet on exercise performance and training adaptations.Most recent literature on the ketogenic diet and exercise performance showed no beneficial effects, especially for trained individuals. During a period of intensified training, performance was clearly impaired during the ketogenic intervention, while a diet with high carbohydrates maintained physical performance. The main effect of the ketogenic diet resides in metabolic flexibility, inducing the metabolism to oxidize more fat for ATP resynthesis regardless of submaximal exercise intensities.The ketogenic diet is not a reasonable nutritional strategy, as it has no advantage over normal/high carbohydrate-based diets on physical performance and training adaptations even when used only in a specific training/nutritional periodization stage.

On Duality Principles and Related Convex Dual Formulations Suitable for Local and Global Non-Convex Variational Optimization

Abstract: This article develops duality principles and related convex dual formulations suitable for the local and global optimization of non-convex primal formulations for a large class of models in physics and engineering. The results are based on standard tools of functional analysis, calculus of variations and duality theory. In particular, we develop applications to a Ginzburg-Landau type equation.