448 research outputs found
Individual tree growth models for eucalyptus in northern Brazil
The diameter and height growth model is one of three submodels used for simulating individual tree growth. In Brazil, there are few studies on the dimensional growth of individual trees be they native or exotic species, despite their potential. This study aimed to evaluate diameter and height growth models for individual trees for eucalyptus stands and to validate the best fitting model. Tree diameter and height data were obtained from 48 permanent plots of unthinned stands of Eucalyptus grandis × Eucalyptus urophylla hybrid located in northern Brazil. The evaluation of the diameter and height growth models was based on adjusted coefficient of determination, standard error of estimate as a percentage, trend, root mean square error and Akaike Information Criterion. Analysis also included distribution of residual percentage, statistical significance and signs of the coefficients. The Lundqvist-Korf model provided the most accurate estimates for diameter and height growth, in comparison with the other models, providing better statistical values, greater proximity to observed values and better distribution of residual percentages. The use of this type of model is feasible and can result in significant improvements in the accuracy of yield estimates
Monte Carlo simulation of hole transport in SiGe alloys
This paper employs Ensemble Monte Carlo method to simulate transport of holes in SiGe alloys. A three-band model was employed to describe the valence band of these alloys. The nonparabolicity and the warping effect of the heavy-hole and light-hole bands were considered in their dispersion relation, while the split-off band was described as parabolic and spherical. We consider phonon and alloy disorder scattering in these calculations. The mobility of holes for a range of SiGe al-loys was calculated at 300K. The simulation mobility results agree with the experimental data, implying that the selected transport model for holes in SiGe alloys is adequate
Cardiopulmonary exercise and 6-min walk tests as predictors of quality of life and long-term mortality among patients with heart failure due to Chagas disease
Universidade Federal de São Paulo, Div Cardiol, São Paulo, BrazilSanta Izabel Hosp, Div Cardiol, Salvador, BrazilBrazilian Clin Res Inst, São Paulo, BrazilDuke Clin Res Inst, Durham, NC USAUniversidade Federal de São Paulo, Div Cardiol, São Paulo, BrazilWeb of Scienc
USE OF QUANTILE REGRESSION AND RANSAC ALGORITHM IN FITTING VOLUME EQUATIONS UNDER THE INFLUENCE OF DISCREPANT DATA
The objective of this study was to evaluate three estimation methods to fit volume equations in the presence of influential or leverage data. To do so, data from the forest inventory carried out by the Centro Tecnológico de Minas Gerais Foundation were used to fit the Schumacher and Hall (1933) model in its nonlinear form for Cerradão forest, considering the quantile regression (QR), the RANSAC algorithm and the nonlinear Ordinary Least Squares (OLS) method. The correlation coefficient ( ) between the observed and estimated volumes, root-mean-square error (RMSE), as well as graphical analysis of the dispersion and distribution of the residuals were used as criteria to evaluate the performance of the methods. After the analysis, the nonlinear least squares method presented a slightly better result in terms of the goodness-of-fit statistics, however it altered the expected trend of the fitted curve due to the presence of influential data, which did not happen with the QR and the RANSAC algorithm, as these were more robust in the presence of discrepant data
EMPOWERMENT OF WOMEN FARMERS MEMBERS TO NETWORK “MÃOS À HORTA”, RIO POMBA/ MG
The research sought to understand gender relations that occur in the women lives farmers that prosumers belong to Network “Mãos a Horta”. This Network it is a alternative form of marketing of Rio Pomba - MG agricultural products, based on solidarity economy principles and strengthening of local family farmers in agroecological transition aimed at producing foods free of pesticides. Gender refers to the socially constructed differences in attributes and opportunities associated with the female or male, and the interactions and social relations between men and women. To analyze whether there is empowerment, we used the prospect of private empowerment (won by the individual) and public empowerment (collectively won). Semi-structured interviews with open and closed questions, interview two models being developed seeking to translate the objectives of the survey were used to collect data. The interview was directed at the women. The interview B was directed to farmers, spouses of these women. Quantitative data were transformed into graphs and tables, and the interviews were recorded with the aid of suitable equipment, and later transcribed. The data obtained were related theory, featuring an explanatory descriptive approach. The analysis of these results led to the conclusion that there are private by empowering these women, but we could not conclude the same about public empowerment
Influência de estimativas de produção de madeira em processos de regulação florestal utilizando programação linear.
The main objective of this work was to evaluate the consequences of the use of yield and growth estimates from different prediction yield and growth models in a Linear Programming model applied to forest regulation. Thus, using data of continuous forest inventory, the yield estimation in future volume was obtained using a yield model based on age, another one based on age and site index, and a third model that used age and site index besides density, which was represented by the basal area per hectare. Also a model based on data of continuous forest inventory which uses data of volume on a period of time to make linear projections of yield for the next period was tested. Next, a simplified forest regulation problem was proposed and solved by the model I by means of Linear Programming, using data from the four volume prediction models. At the end, the conclusion was: a) that models of forest regulation, supplied with estimates from different yield models, when solved by Linear Programming, result in different ways of treating the forests; b) that the matrix of technological coefficients, supplied with different yield data and for a same objective function affects in a significant way the decision making process.Este trabalho teve como principal objetivo avaliar as conseqüências do uso de estimativas de produção oriundas de diferentes modelos de crescimento e produção em um modelo de Programação Linear aplicado à regulação florestal. Assim, utilizando dados de um inventário florestal contínuo, obtiveram-se diferentes estimativas da produção futura em volume, pelo ajuste de um modelo de produção em função da idade, outro em função da idade e do índice de local e por um terceiro modelo que incluiu, além da idade e do índice de local, a densidade, representada pela área basal por hectare. Testou-se também um modelo baseado nos dados de inventário florestal contínuo que utiliza os dados de volume de um período para fazer projeções lineares da produção para o período seguinte. Em seguida, um problema de regulação florestal simplificado foi idealizado e resolvido pelo modelo I por meio de Programação Linear, utilizando dados oriundos dos quatro modelos de predição do volume. Ao final, concluiu-se: a) que modelos de regulação florestal, alimentados por estimativas provenientes de diferentes modelos de produção, quando resolvidos por Programação Linear, resultam em diferentes maneiras de se conduzir a floresta; b) que a matriz de coeficientes tecnológicos, alimentada por diferentes dados de produção e para uma mesma função objetivo, afeta, de maneira significativa, o processo de tomada de decisão
Graduates of Pibid-mathematics: self-evaluation of the first experience of initiation into teaching
The objective of this article is to analyse the process of self-evaluation of undergraduates who are members of the Institutional Program for Scholarship Initiation to Teaching of Mathematics on the first experience of initiation to teaching in Basic Education. The methodological contributions are linked to descriptive research with a qualitative approach. The participants in the research were five undergraduates of the Mathematics Course of Campus IV of the Federal University of Paraíba, who are members of Pibid-Mathematics and work at the Escola Cidadã Integral Senador Rui Carneiro (Mamanguape-PB). The data were collected using an online questionnaire was divided into three categories of analysis: the actions carried out involving the pedagogical workshop; teaching knowledge in the training of the teacher who teaches mathematics; and the narratives regarding the first experience of initiation into teaching and the importance of self-evaluation in pedagogical practice. The results revealed a positive sign in the first class of the graduates, perception and levelled attribution of importance on the knowledge needed for teaching, classification of didactic-pedagogical elements of major concern involved in the experience, and the possibility of giving new meaning to self-assessment, conceiving it as an instrument of regulation in and from initial training.O objetivo deste artigo é analisar o processo de autoavaliação de licenciandos integrantes do Programa Institucional de Bolsas de Iniciação à Docência (Pibid) de Matemática sobre a primeira experiência de iniciação à docência na Educação Básica. Os aportes metodológicos vinculam-se à pesquisa descritiva com abordagem qualitativa. Os participantes da investigação foram cinco Licenciandos do Curso de Matemática do Campus IV – Litoral Norte – Rio Tinto, da Universidade Federal da Paraíba, que são integrantes do Pibid-Matemática e atuam na Escola Cidadã Integral Senador Rui Carneiro (Mamanguape-PB). A coleta de dados utilizou um questionário online, que foi orientado em três categorias de análise: (i) as ações realizadas envolvendo a oficina pedagógica; (ii) os saberes docentes na formação do professor que ensina matemática; e (iii) as narrativas quanto à primeira experiência de iniciação à docência e quanto à importância da autoavaliação na prática pedagógica. Os resultados revelaram um aceno positivo na primeira aula dos pibidianos, percepção e atribuição nivelada de importância sobre os saberes necessários à docência, classificação de elementos didático-pedagógicos de maior inquietação envoltos na experiência e a possibilidade de ressignificar a autoavaliação, concebendo-a como instrumento de regulação na e da formação inicial
Structure of the arboreal component of Cafundó Natural Heritage Private Reserve, Cachoeiro de Itapemirim, Espírito Santo, Brazil
Este estudo teve por objetivo avaliar a estrutura horizontal do componente arbóreo da Reserva Particular do Patrimônio Natural Cafundó, localizada em Cachoeiro de Itapemirim, Espírito Santo. Para tanto, foram alocadas 25 parcelas de 20x50 m (área total: 2,5 hectares) e amostrados todos os indivíduos com DAP ≥5 cm, sendo registrados 4557 indivíduos, distribuídos em 255 espécies, 152 gêneros e 54 famílias. O índice de diversidade (H’) foi de 4,13. Os valores de área basal (33,02 m2.ha-1) e densidade (1823 ind.ha-1) foram próximos aos de outras florestas estacionais semideciduais da região Sudeste. As espécies com maior valor de importância (VI) foram Astronium concinnum, Pseudopiptadenia contorta e Neoraputia alba. O remanescente florestal é composto predominantemente por espécies secundárias tardias, caracterizando-se como um fragmento bem preservado, que detém alta diversidade de espécies e com uma flora arbórea peculiar, ressaltando a importância desta área para conservação na região sul do Espírito Santo.This study aims to evaluate the forest horizontal structure of Cafundó Natural Heritage Private Reserve, located in Cachoeiro de Itapemirim, Espírito Santo. In order to that, twenty five plots were established (total area: 2,5 hectares) and all trees with DBH ≥ 5 cm were surveyed. A total of 4557 individuals were sampled, distributed in 255 species, 152 genera and 54 families. The diversity index (H’) was 4,13. The values of basal area (33,02 m2 .ha-1) and density (1823 ind.ha-1) are closed to the range of other Semideciduous Seasonal Forest in Southeast. The species with the highest importance value (IV) were: Astronium concinnum, Pseudopiptadenia contorta, Neoraputia alba. This forest fragment is composed predominantly by late secondary species and can be characterized as well preserved, with considerable species diversity and peculiar aboreal flora, standing out the ecological importance of this area for conservation in the south region of the Espírito Santo
Methods of estimation of height of trees in Semideciduous Seasonal Forest
O estudo foi realizado na Floresta do Rosal, Guaçuí, ES, para avaliar precisão e tempo de execução de métodos de estimação de altura, em diferentes condições de terreno, com os métodos hipsômetro Vertex (1); clinômetro digital (2); estimação com auxílio de uma régua de 15 metros (3); e estimações visuais com treinamento (4) e sem treinamento (5), em três classes de altura: 1 (15,00-17,99 m); 2 (18,00-20,99 m); e 3 (> 21,00 m). Foram mensurados 124 indivíduos em terreno plano e 87 em terreno inclinado. Os dados de altura foram comparados pelo teste t, análises gráficas de resíduos e estatísticas complementares. Para avaliar o tempo, foi realizado teste t. O método 5 apresentou o pior desempenho quanto à precisão, enquanto que o melhor desempenho foi do método 4. A declividade afetou negativamente o desempenho dos equipamentos digitais e favoreceu o método 3. Houve tendência em subestimar altura com o aumento das classes. Os métodos 4 e 5 consumiram menos tempo e o 3, o maior tempo médio. O efeito da classe no tempo médio em terreno plano foi igual para todos os métodos, à exceção do 2. Em terreno inclinado, os métodos 3 e 4 não tiveram desempenhos alterados.Palavras-chave: Altura total; precisão; tempo.AbstractMethods of estimation of height of trees in Semideciduous Seasonal Forest. The research was conducted in Forest of Rosal, Guaçuí-ES, in order to evaluate accuracy and running time of five height estimating methods in different ground conditions; the methods are as follow: Vertex hypsometer (1); Digital Clinometer (2), estimation with aid of a 15 meters ruler (3), and visual estimation with training (4) and untrained (5) in three height classes: 1 (15.00 - 17.99 m), 2 (18.00 - 20.99 m), and 3 (>21.00 m). It were measured 124 individuals in flat ground and 87 individuals in sloping ground. The height data were compared by t test and residual graphic analysis and additional statistics. To evaluate time, it was improved a t test. The method 5 had the worst performance in terms of accuracy, the best performance was improved by the method 4. The slop affected negatively the digital equipment performance and favored the method 3. There was a tendency to underestimate height as classes increase. The methods 4 and 5 consumed less time and method 3 consumed the highest average time. The class effect on average time on flat ground was the same for all methods but method 2. On slope ground, performance of methods 3 and 4 weren’t altered.Keywords: Height; accuracy; time. AbstractThe research was conducted in Forest of Rosal, Guaçuí-ES, in order to evaluate accuracy and running time of five height estimating methods in different ground conditions; the methods are as follow: Vertex hypsometer (1); Digital Clinometer (2), estimation with aid of a 15 meters ruler (3), and visual estimation with training (4) and untrained (5) in three height classes: 1 (15.00 - 17.99 m), 2 (18.00 - 20.99 m), and 3 (>21.00 m). It were measured 124 individuals in flat ground and 87 individuals in sloping ground. The height data were compared by t test and residual graphic analysis and additional statistics. To evaluate time, it was improved a t test. The method 5 had the worst performance in terms of accuracy, the best performance was improved by the method 4. The slop affected negatively the digital equipment performance and favored the method 3. There was a tendency to underestimate height as classes increase. The methods 4 and 5 consumed less time and method 3 consumed the highest average time. The class effect on average time on flat ground was the same for all methods but method 2. On slope ground, performance of methods 3 and 4 weren’t altered.Keywords: Height; accuracy; time.
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