An adaptive load stepping algorithm for path-dependent problems based on estimated convergence rates

A new adaptive (automatic) time stepping algorithm, called RCA (Rate of Convergence Algorithm) is presented. The new algorithm was applied in nonlinear finite element analysis of path-dependent problems. The step size is adjusted by monitoring the estimated convergence rate of the nonlinear iterative process. The RCA algorithm is relatively simple to implement, robust and its performance is comparable to, and in some cases better than, the automatic load incrementaion algorithm existent in commercial codes. Discussions about the convergence rate of nonlinear iterative processes, an estimation of the rate and a study of the parameters of the RCA algorithm are presented. To show the capacity of the algorithm to adjust the increment size, detailed discussions based on results for different limit load analyses are presented. The results obtained by RCA algorithm are compared with those by ABAQUS®, one of the most powerful nonlinear FEA (Finite Element Analysis) commercial software, in order to verify the capability of RCA algorithm to adjust the increment size along nonlinear analyses

Necessidades de irrigação suplementar em soja nas condições edafoclimáticas do Planalto Médio e Missões, RS.

Este trabalho foi conduzido com a finalidade de estimar as necessidades estocásticas de irrigação suplementar por aspersão na cultura da soja (Glycine max L. Merrill), nas regiões agroecológicas do Estado do Rio Grande do Sul, denominadas de Planalto Médio e Missões. As necessidades foram simuladas em relação à combinação entre locais, épocas de semeadura, níveis de manejo da irrigação e entre níveis de ocorrência . As necessidades de irrigação suplementar foram máximas na semeadura de 15 de outubro, e os menores valores foram encontrados na semeadura de 15 de dezembro; as necessidades de irrigação suplementar foram maiores nas condições agroecológicas das Missões quando comparadas com as do Planalto Médio; as lâminas de irrigação suplementar estimadas aumentaram à medida que o nível de risco diminuiu

Area spectrum and quasinormal modes of black holes

We demonstrate that an equidistant area spectrum for the link variables in loop quantum gravity can reproduce both the thermodynamics and the quasinormal mode properties of black holes.Comment: 11 pages, no figures; references adde

Simulating maize yield in sub-tropical conditions of southern Brazil using Glam model

The objective of this work was to evaluate the feasibility of simulating maize yield in a sub‑tropical region of southern Brazil using the general large area model (Glam). A 16‑year time series of daily weather data were used. The model was adjusted and tested as an alternative for simulating maize yield at small and large spatial scales. Simulated and observed grain yields were highly correlated (r above 0.8; p<0.01) at large scales (greater than 100,000 km2), with variable and mostly lower correlations (r from 0.65 to 0.87; p<0.1) at small spatial scales (lower than 10,000 km2). Large area models can contribute to monitoring or forecasting regional patterns of variability in maize production in the region, providing a basis for agricultural decision making, and Glam‑Maize is one of the alternatives

Short-term add-on therapy with angiotensin receptor blocker for end-stage inotrope-dependent heart failure patients: B-type natriuretic peptide reduction in a randomized clinical trial

OBJECTIVE: We aimed to evaluate angiotensin receptor blocker add-on therapy in patients with low cardiac output during decompensated heart failure. METHODS: We selected patients with decompensated heart failure, low cardiac output, dobutamine dependence, and an ejection fractio

Emotional, hyperactivity and inattention problems in adolescents with immunocompromising chronic diseases during the COVID-19 pandemic

Objective: To assess factors associated with emotional changes and Hyperactivity/Inattention (HI) motivated by COVID-19 quarantine in adolescents with immunocompromising diseases. Methods: A cross-sectional study included&nbsp;343&nbsp;adolescents with immunocompromising diseases and 108&nbsp;healthy adolescents. Online questionnaires were answered including socio-demographic data and self-rated healthcare routine during COVID-19 quarantine and validated surveys: Strengths and Difficulties Questionnaire (SDQ), Pittsburgh Sleep Quality Index (PSQI), Pediatric Quality of Life Inventory 4.0 (PedsQL4.0). Results: The frequencies of abnormal emotional SDQ scores from adolescents with chronic diseases were similar to those of healthy subjects (110/343&nbsp;[32%] vs.&nbsp;38/108 [35%], p&nbsp;=&nbsp;0.548), as well as abnormal hyperactivity/inattention SDQ scores (79/343 [23%] vs.&nbsp;29/108 [27%], p&nbsp;=&nbsp;0.417). Logistic regression analysis of independent variables associated with abnormal emotional scores from adolescents with chronic diseases showed: female sex (Odds Ratio [OR&nbsp;=&nbsp;3.76]; 95%&nbsp;Confidence Interval (95%&nbsp;CI) 2.00‒7.05; p &lt; 0.001), poor sleep quality (OR&nbsp;=&nbsp;2.05; 95%&nbsp;CI&nbsp;1.08‒3.88; p&nbsp;=&nbsp;0.028) and intrafamilial violence during pandemic (OR&nbsp;=&nbsp;2.17; 95%&nbsp;CI&nbsp;1.12‒4.19; p&nbsp;=&nbsp;0.021) as independently associated with abnormal emotional scores, whereas total PedsQL score was inversely associated with abnormal emotional scores (OR&nbsp;=&nbsp;0.95; 95%&nbsp;CI&nbsp;0.93‒0.96; p &lt; 0.0001). Logistic regression analysis associated with abnormal HI scores from patients evidenced that total PedsQL score (OR&nbsp;=&nbsp;0.97; 95%&nbsp;CI&nbsp;0.95‒0.99; p&nbsp;=&nbsp;0.010], changes in medical appointments during the pandemic (OR&nbsp;=&nbsp;0.39; 95%&nbsp;CI&nbsp;0.19-0.79; p&nbsp;=&nbsp;0.021), and reliable COVID-19 information (OR&nbsp;=&nbsp;0.35; 95%&nbsp;CI&nbsp;0.16‒0.77; p&nbsp;=&nbsp;0.026) remained inversely associated with abnormal HI scores. Conclusion: The present study showed emotional and HI disturbances in adolescents with chronic immunosuppressive diseases during the COVID-19 pandemic. It reinforces the need to promptly implement a longitudinal program to protect the mental health of adolescents with and without chronic illnesses during future pandemics

Adaptação e avaliação do modelo infocrop para simulação do rendimento de grãos da cultura do arroz irrigado

Este trabalho teve como objetivo adaptar e avaliar o modelo InfoCrop para simulação do rendimento de grãos da cultura do arroz irrigado, em Santa Maria - RS. O rendimento de grãos da cultura do arroz irrigado foi simulado, considerando-se três versões do modelo InfoCrop com adaptações para cultivares locais. Os rendimentos simulados foram comparados com os rendimentos observados no município de Santa Maria, no período 1996/1997 a 2008/2009, disponibilizados pelo Instituto Riograndense do Arroz (IRGA), e com rendimentos de experimentos realizados na Universidade Federal de Santa Maria (UFSM), entre os anos agrícolas de 1998/1999 e 2005/2006. O modelo InfoCrop capturou a variação interanual do rendimento de grãos de arroz irrigado para o município de Santa Maria e dos experimentos realizados na UFSM. A raiz do erro quadrático médio da simulação de rendimento de grãos com a Versão 3 do modelo InfoCrop (melhor desempenho), considerando todo o conjunto de dados observados, foi de 0,850 Mg ha-1, com tendência de superestimativa, que pode ter ocorrido pelo fato de o modelo considerar uma situação de rendimento potencial, o que nem sempre acontece em lavouras comerciais.This study aimed to adapt and evaluate the InfoCrop model for simulating grain yield of irrigated rice in Santa Maria, state of Rio Grande do Sul, Brazil. The grain yield of irrigated rice was simulated considering three versions of the InfoCrop model with adaptations for local rice cultivars. Simulated yields were compared to the yields observed in the Santa Maria county surveyed by the Instituto Riograndense do Arroz (Institute of Rice of Rio Grande do Sul - IRGA) from 1996/97 to 2008/09, and to the yields of experiments conducted at the Universidade Federal de Santa Maria (Federal University of Santa Maria - UFSM) from 1998/1999 to 2005/2006. The InfoCrop model captured the interannual variability of the grain yield of irrigated rice for the Santa Maria county and the experiments conducted at UFSM. The root mean squared error of the simulation of grain yield using the Version 3 of the InfoCrop model (better performance), considering all data observed, was 0.850 Mg ha-1, with overestimation trend, which may have occurred because the model considers a situation of potential yield, which does not always occur in commercial farming