Dos desvios das médias dos grupos contemporâneos aos modelos animais

O objetivo deste trabalho foi apresentar a reparametrização de um modelo de desvios das médias dos grupos contemporâneos até um modelo animal não-restrito (equações dos modelos mistos de Lush - EMML). Aplicando restrições sobre as EMML, foi obtido o modelo animal segundo Henderson (equações dos modelos mistos de Henderson - EMMH). Para obter as EMMH, restrições do tipo X'A-1λ aH = 0 foram impostas e estas geraram a necessidade de pressuposições fortes, como ausência de seleção, para que as propriedades das EMMH pudessem ser provadas. Para diferentes situações examinadas, as restrições foram confirmadas. O somatório destas restrições pode ser erroneamente interpretado como propriedade das soluções de um modelo animal de que os animais-base tenham a soma dos seus valores genéticos igual a zero.

Curvas de lactação em rebanhos da raça holandesa no estado de Minas Gerais. Escolha do modelo de melhor ajuste

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Uniform estimates of attracting sets of extended Lurie systems using LMIs

This research presents a systematic procedure to obtain estimates, via extended Lyapunov functions, of attracting sets of a class of nonlinear systems, as well as an estimate of their stability regions. The considered class of nonlinear systems, called in this note the extended Lurie system, consists of nonlinear systems like those of the Lurie problem where one of the nonlinear functions can violate the sector conditions of the Lurie problem around the origin. In case of nonautonomous systems the concept of absolute stability is extended and uniform estimates of the attracting set are obtained. Two classical nonlinear systems, the forced duffing equation and the Van der Pol system, are analyzed with the proposed procedure.

Efeito da irrigação na produtividade da cultura do trigo

Estudou-se o efeito da irrigação na produtividade final da cultura do trigo por meio de um ensaio, com duração variável do período em que foram feitas as irrigações. Todos os períodos tiveram início na data do plantio. O ensaio foi instalado em Botucatu, Estado de São Paulo, em Latossolo Roxo, plano, de baixada, sem adubação e sem calagem, usando a cultivar BH 1146. A cultura se desenvolveu sob boas condições climáticas, tendo completado o ciclo de 118 dias. Correlacionou-se a produtividade final da cultura com a água aplicada em períodos com durações que variaram de 20 a 110 dias. Foram obtidas 49 equações lineares simples entre a altura de água aplicada e a produtividade de grifos de trigo. Estudou-se a variação da produtividade da cultura para aumentos de 1 mm na altura de água aplicada nos períodos referidos, encontrando-se uma variação de 767.7% na taxa de aproveitamento da água. Analisou-se o incremento de produtividade da cultura para a aplicação de 1 mm de altura d'água em cada dez dias de duração do período considerado. Os incrementos de produtividade apresentaram uma variação de 600,5%. Por fim, estimou-se o nível de irrigação necessário para atingir determinados níveis de produtividade de trigo.

Comparação entre a adiposidade subcutânea dos hemicorpos direito e esquerdo

O objetivo deste estudo foi comparar os níveis de adiposidade subcutânea dos hemicorpos direito e esquerdo e, posteriormente, analisar o impacto dessas informações para o estudo da composição corporal. Setenta e seis indivíduos fisicamente ativos, 47 homens (21,6 ± 4,3 anos) e 29 mulheres (21,0 ± 2,6 anos), fizeram parte da amostra. As espessuras das dobras cutâneas abdominal, suprailíaca, subescapular, tricipital, bicipital, axilar média e perna medial foram mensuradas com um compasso Lange. Em valores médios absolutos, as maiores diferenças verificadas foram de 0,9mm (6,9%) e 0,8mm (6,8%), na dobra cutânea suprailíaca de homens e mulheres, respectivamente. Entretanto, nenhuma diferença estatisticamente significante foi encontrada na comparação entre os lados, em ambos os sexos, nas sete dobras cutâneas analisadas (P > 0,05). Similarmente, quando os valores medidos foram aplicados em equações preditivas para a determinação da gordura corporal relativa, de acordo com o sexo, nenhuma diferença significante foi encontrada (P > 0,05). Os resultados sugerem que fatores como o erro técnico de medida do avaliador, o tipo de compasso e a escolha da equação preditiva a ser utilizada, provavelmente tenham maior impacto para a estimativa da composição corporal pelo método de espessura de dobras cutâneas do que o lado a ser adotado como referência para a obtenção das medidas.

A Short Note on a Nonlinear System vibrations under Two Non-Ideal Excitations

This paper describes a nonlinear phenomenon in the dynamical behavior of a nonlinear system under two non-ideal excitations: the self-synchronization of unbalanced direct current motors. The considered model is taken as a Duffing system that is excited by two unbalanced direct current motors with limited power supplies. The results obtained by using numerical simulations are discussed in details.

On numerical simulations of a nonlinear self-excited system with two non-ideal sources

In this work, the dynamic behavior of self-synchronization and synchronization through mechanical interactions between the nonlinear self-excited oscillating system and two non-ideal sources are examined by numerical simulations. The physical model of the system vibrating consists of a non-linear spring of Duffing type and a nonlinear damping described by Rayleigh's term. This system is additional forced by two unbalanced identical direct current motors with limited power (non-ideal excitations). The present work mathematically implements the parametric excitation described by two periodically changing stiffness of Mathieu type that are switched on/off. Copyright © 2005 by ASME.

Optimal linear and nonlinear control design for chaotic systems

In this work, the linear and nonlinear feedback control techniques for chaotic systems were been considered. The optimal nonlinear control design problem has been resolved by using Dynamic Programming that reduced this problem to a solution of the Hamilton-Jacobi-Bellman equation. In present work the linear feedback control problem has been reformulated under optimal control theory viewpoint. The formulated Theorem expresses explicitly the form of minimized functional and gives the sufficient conditions that allow using the linear feedback control for nonlinear system. The numerical simulations for the Rössler system and the Duffing oscillator are provided to show the effectiveness of this method. Copyright © 2005 by ASME.

On the dynamic behaviour of a nonlinear system weakly connected to a linear single degree-of-freedom system

This paper discusses the dynamic behaviour of a nonlinear two degree-of-freedom system consisting of a harmonically excited linear oscillator weakly connected to a nonlinear attachment that behaves as a hardening Duffing oscillator. A system which behaves in this way could be a shaker (linear system) driving a nonlinear isolator. The mass of the nonlinear system is taken to be much less than that in the linear system and thus the nonlinear system has little effect on the dynamics of the linear system. Of particular interest is the situation when the linear natural frequency of the nonlinear system is less than the natural frequency of the linear system such that the frequency response curve of the nonlinear system bends to higher frequencies and thus interacts with the resonance frequency of the linear system. It is shown that for some values of the system parameters a complicated frequency response curve for the nonlinear system can occur; closed detached curves can appear as a part of the overall amplitude-frequency response. The reason why these detached curves appear is presented and approximate analytical expressions for the jump-up and jump-down frequencies of the system under investigation are given.

Perda de carga em mangueiras gotejadoras novas e usadas

This paper aims to determine the importance of emitter ́s local head loss in the hydraulic design of hose drip lines, as well as comparing the result of equations that calculate the local head loss; besides verifying the influence of iron precipitated at the hose head loss made in Brazil. The result found that localized head loss represents 23% of the total head loss; the equations showed significant results and the total head loss increased in an average of 20% after the irrigation system was used with water rich in iron.

Predição da potência aeróbia (VO 2máx) de crianças e adolescentes em teste incremental na esteira rolante

The maximal oxygen uptake (VO2max) is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO 2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO 2max: VO2max (ml/min) = -1574.06 + (141.38 x Vpeak) + (48.34 * Body mass), with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min) and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

Análise química da folha d de abacaxizeiro cv. smooth cayenne antes e após a indução floral em função de doses e parcelamentos de nitrogênio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Acúmulo e exportação de nutrientes em cenoura 'Forto'

In order to quantify the growth, accumulation and exportation of macronutrients by carrot 'Forto', and obtain equations that best represent them, it was conducted an experiment in the São Gotardo (MG), from May to September 2004. Samples were taken at 40, 50, 60, 70, 80, 90, 100, 110 and 120 days after sowing (DAS) to determine dry matter and accumulation of macronutrients in leaves and roots. At 40 DAS, five days after thinning, the plants had 0.18 g and 0.04 g in dry leaves (LDM) and of roots (RDM), respectively. From then, until 88 DAS, the partitioning of photoassimilates and accumulation of matter in the shoots were more pronounced. The RDM was low until 80 DAS, which corresponded to two thirds of the crop cycle, from when the amount of material allocated in this part of the plant had strong growth, surpassing, at 88 DAS, the amount of LDM. The nutrient accumulation was small in the first 60 DAS, coinciding with the period of lower dry matter accumulation. The order of decreasing macronutrient accumulation by the crop were: K > N > Ca > P > S > Mg, in the amounts of 906.7, 438, 155.46, 87.4, 58 and 37.63 mg plant-1, respectively. The root participated with 60.5% of the accumulation of N, 86.1% of P, 58% of K, 25.5% of Ca, 55.6% of Mg and 65.5% of S. Considering a population of 590,000 plants per hectare, the total quantity of nutrients by the crop of carrots was 258.3, 51.6, 534.8, 91.7, 22.2 and 34.2 kg N ha-1, P, K, Ca, Mg and S, respectively.

A non-ideal portal frame energy harvester controlled using a pendulum

A model of energy harvester based on a simple portal frame structure is presented. The system is considered to be non-ideal system (NIS) due to interaction with the energy source, a DC motor with limited power supply and the system structure. The nonlinearities present in the piezoelectric material are considered in the piezoelectric coupling mathematical model. The system is a bi-stable Duffing oscillator presenting a chaotic behavior. Analyzing the average power variation, and bifurcation diagrams, the value of the control variable that optimizes power or average value that stabilizes the chaotic system in the periodic orbit is determined. The control sensitivity is determined to parametric errors in the damping and stiffness parameters of the portal frame. The proposed passive control technique uses a simple pendulum to tuned to the vibration of the structure to improve the energy harvesting. The results show that with the implementation of the control strategy it is possible to eliminate the need for active or semi active control, usually more complex. The control also provides a way to regulate the energy captured to a desired operating frequency. © 2013 EDP Sciences and Springer.

Potencial produtivo de cultivares de cana-de-açúcar sob os manejos irrigado e sequeiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)