Critical dynamics of the Potts model: short-time Monte Carlo simulations

We calculate the new dinamic exponent $\theta$ of the 4-state Potts model, using short-time simulations. Our estimates $\theta_{1}=-0.0471(33)$ and $\theta_{2}=$ $-0.0429(11)$ obtained by following the behavior of the magnetization or measuring the evolution of the time correlation function of the magnetization corroborate the conjecture by Okano et. al. In addition, these values agree with previous estimate of the same dynamic exponent for the two-dimensional Ising model with three-spin interactions in one direction, that is known to belong to the same universality class as the 4-state Potts model. The anomalous dimension of initial magnetization $$ is calculated by an alternative way that mixes two different initial conditions. We have also estimated the values of the static exponents $\beta$ and $\nu$. They are in complete agreement with the pertinent results of the literature.Comment: 12 pages, 7 figure

Scaling behavior of the directed percolation universality class

In this work we consider five different lattice models which exhibit continuous phase transitions into absorbing states. By measuring certain universal functions, which characterize the steady state as well as the dynamical scaling behavior, we present clear numerical evidence that all models belong to the universality class of directed percolation. Since the considered models are characterized by different interaction details the obtained universal scaling plots are an impressive manifestation of the universality of directed percolation.Comment: 24 pages, 7 figures, accepted for publication in Nuclear Physics

An alternative order parameter for the 4-state Potts model

We have investigated the dynamic critical behavior of the two-dimensional 4-state Potts model using an alternative order parameter first used by Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of the Z(5) model. We have estimated the global persistence exponent $\theta_g$ by following the time evolution of the probability $P(t)$ that the considered order parameter does not change its sign up to time $t$. We have also obtained the critical exponents $\theta$, $z$, $\nu$, and $\beta$ using this alternative definition of the order parameter and our results are in complete agreement with available values found in literature.Comment: 6 pages, 6 figure

A comparative study of the dynamic critical behavior of the four-state Potts like models

We investigate the short-time critical dynamics of the Baxter-Wu (BW) and $n=3$ Turban (3TU) models to estimate their global persistence exponent $\theta _{g}$. We conclude that this new dynamical exponent can be useful in detecting differences between the critical behavior of these models which are very difficult to obtain in usual simulations. In addition, we estimate again the dynamical exponents of the four-state Potts (FSP) model in order to compare them with results previously obtained for the BW and 3TU models and to decide between two sets of estimates presented in the current literature. We also revisit the short-time dynamics of the 3TU model in order to check if, as already found for the FSP model, the anomalous dimension of the initial magnetization $x_{0}$ could be equal to zero

Global persistence exponent of the two-dimensional Blume-Capel model

The global persistence exponent $\theta_g$ is calculated for the two-dimensional Blume-Capel model following a quench to the critical point from both disordered states and such with small initial magnetizations. Estimates are obtained for the nonequilibrium critical dynamics on the critical line and at the tricritical point. Ising-like universality is observed along the critical line and a different value $\theta_g =1.080(4)$ is found at the tricritical point.Comment: 7 pages with 3 figure

Levy distribution and long correlation times in supermarket sales

Sales data in a commodity market (supermarket sales to consumers) has been analysed by studying the fluctuation spectrum and noise correlations. Three related products (ketchup, mayonnaise and curry sauce) have been analysed. Most noise in sales is caused by promotions, but here we focus on the fluctuations in baseline sales. These characterise the dynamics of the market. Four hitherto unnoticed effects have been found that are difficult to explain from simple econometric models. These effects are: (1) the noise level in baseline sales is much higher than can be expected for uncorrelated sales events; (2) weekly baseline sales differences are distributed according to a broad non-Gaussian function with fat tails; (3) these fluctuations follow a Levy distribution of exponent alpha = 1.4, similar to financial exchange markets and in stock markets; and (4) this noise is correlated over a period of 10 to 11 weeks, or shows an apparent power law spectrum. The similarity to stock markets suggests that models developed to describe these markets may be applied to describe the collective behaviour of consumers.Comment: 19 pages, 7 figures, accepted for publication in Physica

La Educación Rural en el contexto de América Latina y las Escuelas con Clases Multigrado: Otras reflexiones desde los Estudios Poscoloniales

O presente texto é fruto de uma pesquisa de mestrado concluída. Dissertação esta que buscou compreender as expectativas da comunidade campesina sobre a escola com turmas multisseriadas do campo. Desta forma, este artigo teve por objetivo compreender os sentidos da Educação do Campo no contexto da América Latina e as concepções que alicerçam a construção de Escola, Escola do Campo e Escola com turmas multisseriadas do campo. As reflexões aqui realizadas tomaram como lente teórico-metodológica os Estudos Pós-Coloniais, por nos possibilitar problematizar os processos de inferiorização e silenciamento impostos aos povos campesinos, a seus territórios e os seus processos de escolarização. Apontamos como resultados que Educação do Campo no cenário da América Latina necessita ser compreendida como uma possibilidade outra de romper as heranças coloniais impostas pela lógica eurocêntrica e urbanocêntrica. A América Latina constitui-se enquanto um espaço-tempo plural com saberes-fazeres outros válidos que protagonizam ações decoloniais ao reivindicarem e ressignificarem seu lugar-tempo na história e na construção educacional. Consideramos, nessa direção, que os povos do campo reconhecem a escola enquanto uma instituição que contribui na formação dos sujeitos, pois isso seguem reivindicando por uma escola socialmente referenciada em seus sujeitos-territórios. Assim, no bojo dessa discussão, consideramos que a organização das escolas do campo, a partir da multisseriação, configura-se enquanto uma possibilidade de se manterem ativas as instituições educacionais no território campesino e que, a partir de uma prática curricular e pedagógica alinhada com a realidade dos(as) estudantes de diferentes idades/anos-série, é possível promover processos de ensino e aprendizagem críticos, reflexivos e decolonais.This text is the result of a completed master's research. This dissertation sought to understand the expectations of the peasant community about the school with multigrade classes in the countryside. In this way, this article aimed to understand the meanings of Rural Education in the context of Latin America and the conceptions that underpin the construction of School, Rural School and School with multigrade rural classes. The reflections carried out here took Post-Colonial Studies as a theoretical-methodological lens, as it allows us to problematize the processes of inferiorization and silencing imposed on peasant peoples, their territories and their schooling processes. We point out as results that Rural Education in the Latin American scenario needs to be understood as another possibility to break the colonial inheritances imposed by the Eurocentric and urbancentric logic. Latin America is constituted as a plural space-time with other valid know-hows that carry out decolonial actions by claiming and re-signifying their place-time in history and in educational construction. In this sense, we consider that rural people recognize the school as an institution that contributes to the formation of subjects, as they continue to demand a school that is socially referenced in their subject-territories. Thus, in the midst of this discussion, we consider that the organization of rural schools, based on multiseriation, is configured as a possibility of keeping educational institutions active in the rural territory and that, based on a curricular and pedagogical practice aligned with the reality of students of different ages/grades, it is possible to promote critical, reflexive and decolonial teaching and learning processes.Este texto es el resultado de una investigación de maestría finalizada. Esta disertación buscó comprender las expectativas de la comunidad campesina sobre la escuela con clases multigrado en el campo. De esta forma, este artículo tuvo como objetivo comprender los significados de la Educación Rural en el contexto de América Latina y las concepciones que sustentan la construcción de Escuela, Escuela Rural y Escuela con clases rurales multigrado. Las reflexiones aquí realizadas tomaron como lente teórico-metodológico los Estudios Poscoloniales, en tanto permiten problematizar los procesos de inferiorización y silenciamiento impuestos a los pueblos campesinos, sus territorios y sus procesos de escolarización. Señalamos como resultados que la Educación Rural en el escenario latinoamericano necesita ser entendida como una posibilidad más para romper con las herencias coloniales impuestas por las lógicas eurocéntricas y urbancéntricas. América Latina se constituye como un espacio-tiempo plural con otros saberes válidos que realizan acciones decoloniales al reclamar y resignificar su lugar-tiempo en la historia y en la construcción educativa. En ese sentido, consideramos que la población rural reconoce a la escuela como una institución que contribuye a la formación de sujetos, pues siguen demandando una escuela socialmente referenciada en sus territorios-sujetos. Así, en medio de esta discusión, consideramos que la organización de las escuelas rurales, a partir de la multiseriación, se configura como una posibilidad de mantener activas las instituciones educativas en el territorio rural y que, a partir de una práctica curricular y pedagógica alineada con la realidad de estudiantes de diferentes edades/grados, es posible promover procesos de enseñanza y aprendizaje críticos, reflexivos y decoloniales

Diretrizes sustentáveis na concepção da habitação: integração entre o social, o econômico e o ambiental

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. ArquiteturaTCC sem resumo

Validade do limiar de variabilidade da frequência cardíaca para a estimativa do primeiro limiar ventilatório em mulheres jovens

Tese (doutorado)—Universidade de Brasília, Faculdade de Educação Física, Programa de Pós-Graduação em Educação Física, 2021.Introdução: A medida do 1° limiar ventilatório (LV1) permite a individualização das zonas funcionais de treinamento cardiorrespiratório e a predição de saúde e desempenho físico em algumas modalidades esportivas. No entanto o alto custo operacional torna essa medida inacessível à grande parte da população. Assim, o limiar de variabilidade da frequência cardíaca (LVFC) surge como uma alternativa prática e de baixo para a estimativa do LV1 a partir do registro dos intervalos R-R durante um teste de esforço incremental. Entretanto, a validade do LVFC ainda precisa ser confirmada em mulheres, sendo também necessário investigar potenciais fatores que possam influenciar a concordância entre o LVFC e o LV1. Objetivos: Avaliar a concordância entre o LVFC e o LV1 em mulheres submetidas a um teste incremental cardiopulmonar máximo e investigar os possíveis efeitos do perfil antropométrico, nível de aptidão cardiorrespiratória e grau de modulação cardiovagal dos avaliados sobre a concordância entre as técnicas. Métodos: 61 mulheres foram submetidas ao teste incremental cardiopulmonar máximo, em esteira rolante, onde as varáveis ventilatórias e a dinâmica cardiovagal foram continuamente analisadas. O LV1 foi identificado a partir da inflexão do equivalente ventilatório do oxigênio sem aumento recíproco do equivalente ventilatório de CO2, e o LVFC foi determinado a partir da estabilização do índice SD1 da Plotagem de Poincaré avaliada por 4 diferentes critérios: inspeção visual (LVFCVisual), Dmax (LVFCDmax), 1° estágio com valores de SD1 < 3ms (LVFC3ms) e estágio em que as duas variações subsequentes do SD1 foram inferiores a 1 ms (LVFC1ms). As comparações entre o LV1 e os diferentes métodos de determinação do LVFC foram realizadas por meio do teste t dependente (p < 0,05) e a concordância entre as técnicas analisada por meio do método de Bland-Altman. Resultados: Não foram observadas diferenças entre as cargas correspondentes às diferentes técnicas de determinação do LVFC e o LV1 (p > 0,05), exceto para LVFC1ms (p= 0,01). Quanto à análise de concordância, foram observados os seguintes desfechos [viés (limites de concordância)]: LVFCVisual: -0,09 (-1,6 a 1,4), LVFCDmax: -0,09 (-1,6 a 1,4), LVFC3ms: -0,01 (-2,1 a 2,1) e LVFC1ms: 0,42 (-1,8 a 2,7). Os limites de concordância foram menores em participantes com alta aptidão cardiorrespiratória e maior grau de modulação cardiovagal, mas sem efeitos consistentes do IMC. Conclusão: A concordância entre o LVFC e o LV1 é dependente do método utilizado para a identificação da estabilização do índice SD1, com valores mais promissores identificados para os métodos LVFCVisual e LVFCDmax. Por fim, a concordância entre as técnicas é mais promissora em mulheres com alto grau modulação vagal sobre o coração e nível de aptidão cardiorrespiratória.Introduction: The measurement of the 1st ventilatory threshold (LV1) allows the individualization of the functional areas of cardiorespiratory training and the prediction of health and physical performance in some sports. However, the high operational cost makes this measure inaccessible to a large part of the population. Thus, the heart rate variability threshold (LVFC) emerges as a practical and low-cost alternative for estimating LV1 from the record of R-R intervals during an incremental exercise test. However, the validity of the LVFC still needs to be confirmed in women, and it is also necessary to investigate potential factors that may influence the agreement between the LVFC and the LV1. Objectives: To evaluate the agreement between the LVFC and the LV1 in women submitted to a maximum incremental cardiopulmonary test and to investigate the possible effects of the anthropometric profile, level of cardiorespiratory fitness, and degree of cardiovascular modulation of those evaluated on the agreement between the techniques. Methods: 61 women were submitted to the maximum incremental cardiopulmonary test on a treadmill, where the ventilatory variables and cardiovascular dynamics were continuously analyzed. LV1 was identified from the inflection of the oxygen ventilatory equivalent without a reciprocal increase in the ventilatory equivalent of CO2. The LVFC was determined from the stabilization of the SD1 index of the Poincaré plot evaluated by 4 different criteria: visual inspection (LVFCVisual), Dmax (LVFCDmax), 1st stage with SD1 values <3ms (LVFC3ms), and stage where the two subsequent variations of SD1 were less than 1 ms (LVFC1ms). The comparisons between LV1 and the different methods of determining the LVFC were performed using the dependent t-test (p <0.05). The agreement between the techniques was analyzed using the Bland-Altman method. Results: There were no differences between the loads corresponding to the different techniques for determining LVFC and LV1 (p> 0.05), except for LVFC1ms (p = 0.01). As for the analysis of agreement, the following outcomes were observed [bias (limits of agreement)]: LVFCVisual: - 0.09 (-1.6 to 1.4), LVFCDmax: -0.09 (-1.6 to 1.4), LVFC3ms: -0.01 (-2.1 to 2.1) and LVFC1ms: 0.42 (-1.8 to 2.7). The limits of agreement were lower in participants with high cardiorespiratory fitness and a higher degree of cardiovagal modulation, but without consistent effects of BMI. Conclusion: The agreement between the LVFC and LV1 is dependent on the method used to identify the stabilization of the SD1 index, with the LVFCVisual and LVFCDmax methods being more promising than the others. Finally, the techniques' agreement is more promising in women with a high degree of vagal modulation over the heart and level of cardiorespiratory fitness