An Efficient FEM-SFEM Iterative Coupling Procedure for Elastodynamic Problems

In the present work, an efficient iterative coupling methodology between the Finite Element Method (FEM) and the Spectral Finite Element Method (SFEM) for the modeling of elastodynamic problems in the time domain is presented. The methodology allows the use of a nonconforming mesh at the interface between the subdomains, as well as independent time-step sizes within each subdomain. By minimizing a square error functional, an adaptive strategy for the relaxation parameter can be established in the iterative process, increasing the efficiency of the FEM-SFEM coupled analysis. Numerical simulations are presented in order to illustrate the accuracy and potentialities of the proposed methodology.Publicado en: Mecánica Computacional vol. XXXV no.33Facultad de Ingenierí

Eigenfunctions and fundamental solutions of the Caputo fractional Laplace and Dirac operators

In this paper, by using the method of separation of variables, we obtain eigenfunctions and fundamental solutions for the three parameter fractional Laplace operator defined via fractional Caputo derivatives. The solutions are expressed using the Mittag-Leffler function and we show some graphical representations for some parameters. A family of fundamental solutions of the corresponding fractional Dirac operator is also obtained. Particular cases are considered in both cases

Eigenfunctions and fundamental solutions for the Fractional Laplacian in 3 dimensions

Recently there has been a surge of interest in PDEs involving fractional derivatives in different fields of engineering. In this extended abstract we present some of the results developed in \cite{FV}. We compute the fundamental solution for the three-parameter fractional Laplace operator $\Delta^{(\alpha,\beta,\gamma)}$ with $(\alpha, \beta, \gamma) \in \,]0,1]^3$ by transforming the eigenfunction equation into an integral equation and applying the method of separation of variables. The obtained solutions are expressed in terms of Mittag-Leffer functions. For more details we refer the interested reader to \cite{FV} where it is also presented an operational approach based on the two Laplace transform

Multidimensional time fractional diffusion equation

In this paper we present integral and series representations for the fundamental solution of the time fractional diffusion equation in an arbitrary dimension. The series representation obtained depends on the parity of the dimension. As an application of our results we study the diffusion and stress in the axially symmetric case for plane deformation associated to generalized thermoelasticity theory

Fundamental solution of the multi-dimensional time fractional telegraph equation

In this paper we study the fundamental solution (FS) of the multidimensional time-fractional telegraph equation with time-fractional derivatives of orders $\alpha \in ]0,1]$ and $\beta \in ]1,2]$ in the Caputo sense. Using the Fourier transform we obtain an integral representation of the FS expressed in terms of a multivariate Mittag-Leffler function in the Fourier domain. The Fourier inversion leads to a double Mellin-Barnes type integral representation and consequently to a H-function of two variables. An explicit series representation of the FS, depending on the parity of the dimension, is also obtained. As an application, we study a telegraph process with Brownian time. Finally, we present some moments of integer order of the FS, and some plots of the FS for some particular values of the dimension $n$ and of the fractional parameters $\alpha$ and $\beta$

Determinação de fósforo biodisponível em rações de peixes utilizando extração assistida por ultra-som e espectrofotometria no visível

The aim of the present work was to develop and optimize a method for determination of bioavailable phosphorus in samples of feces and fish feed using ultrasound extraction and subsequent quantification by visible spectrophotometry. Using as extractor solution HNO3 0.50 mol L-1, the great conditions of extraction established were: sample mass - 100 mg, samples granulometry - < 60 µm, sonification time - five cycles of 40 s and ultrasound potency - 136 W. The proposed method was applied in studies of digestibility of this nutrient in different feeds used in diets of juvenile of Nile tilapia

Spontaneous perirenal hematoma in a lupic patient on haemodialysis treatment and with renal cysts

The spontaneous perirenal hemorrhage usually presents as sudden pain in the side ipsilateral, no history of trauma. Acquired cystic kidney disease is a common finding in chronic hemodialysis patients. However, spontaneous bleeding from the rupture of the cyst is a rare clinical entity. We describe the case of a female patient, 45 years old, with controlled hypertension for 8 years, chronic renal failure for 15 years and lupus nephritis 2 years ago, undergoing hemodialysis three times a week since 2006, and who presented concurrently acquired cystic kidney disease. She was admitted to the emergency department complaining of sudden onset of pain in the thoraco-abdominal left. Perirenal hematoma was diagnosed by ultrasound and computed tomography of the abdomen. The patient underwent embolization of left renal artery, with good evolution.A hemorragia perirrenal espontânea apresenta-se mais comumente como dor súbita no flanco ipsilateral, sem história de trauma. A doença renal cística adquirida é um achado frequente em pacientes sob tratamento hemodialítico crônico. Entretanto, a hemorragia espontânea proveniente da ruptura dos cistos é uma entidade clínica rara. Descrevemos o caso de uma paciente do sexo feminino, 45 anos, portadora de hipertensão arterial sistêmica controlada há 8 anos, de insuficiência renal crônica por 15 anos e de nefrite lúpica há 2 anos, em tratamento hemodialítico três vezes por semana desde 2006, e que apresentava concomitantemente doença renal cística adquirida. Foi admitida no setor de emergência queixando-se de aparecimento súbito de dor em região toracoabdominal esquerda. Diagnosticou-se hematoma perirrenal por meio de ultrassonografia e tomografia computadorizada de abdômen. A paciente foi submetida à embolização da artéria renal esquerda, com boa evolução.Escola Paulista de MedicinaUNIFESP, EPMSciEL

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio