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Search Results: 1 - 10 of 15936 matches for " Guilherme Garcia Holderbaum "
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Rela o da Atividade Profissional com Desvios Posturais e Encurtamentos Musculares Adaptativos
Guilherme Garcia Holderbaum,Cláudia Tarrag? Candotti,Ana Maria Steffens Pressi,Janete Christianus
Movimento , 2002,
Abstract: The purpose of this study was to verify if the bad adopted postures in the work atmosphere, during the accomplishment of professional actívities can favor the appearance of posture deviations. The s ample wasmade up of 19 employees of the cleaning department from UNISINOS. The methodology used in this research was constituted by the accomplishment of posture goniometrícal evaluarions in order to verify the posture alterations and the amplitude of articular movements, respectively. The obtained results showed that 100% of the individuals presented at least a type of posture deviation. These results suggest that professional acdvities when practised n inadequate postures favor the installaüon of posture deviadons. The posture and goniometrícal evaluations, when correlated presented signifícant dirferences (p£0,05)in comparison with the averages of ADM among the individuais with corporal segments inside and out the norma lposture alignment.
Intera o de variáveis biomecanicas na composi o de "feedback" visual aumentado para o ensino do ciclismo Interacción de variables biomecánicas en la composición de feedback visual aumentado para el ense anza del ciclismo Interaction of biomechanical variables in the composition of visual augmented feedback for learning cycling
Guilherme Garcia Holderbaum,Ricardo Demétrio de Souza Petersen,Ant?nio Carlos Stringhini Guimar?es
Revista Brasileira de Educa??o Física e Esporte , 2012, DOI: 10.1590/s1807-55092012000400003
Abstract: O objetivo deste estudo foi testar uma metodologia para o ensino da técnica da pedalada do ciclismo utilizando variáveis biomecánicas para desenvolver um sistema de "feedback" visual aumentado (FVA). Participaram do estudo 19 indivíduos, sem experiência no ciclismo , divididos em grupo experimental (n = 10) e controle (n = 9). Inicialmente foi realizado um pré-teste para determinar o consumo máximo de oxigênio (VO2máx) bem como a carga de trabalho utilizada nas sess es práticas que correspondeu a 60% do VO2máx. Em seguida foram realizadas sete sess es de prática. O grupo experimental foi submetido ao FVA e o grupo controle ao "feedback" aumentado (FA). O teste de reten o mostrou um aumento de 21 % na média do índice de efetividade (IE) do grupo experimental quando comparado ao grupo controle. Os resultados mostraram que variáveis biomecánicas s o apropriadas para o desenvolvimento de FVA e podem contribuir no processo de ensino-aprendizagem da técnica da pedalada do ciclismo. El objetivo de este estudio fue probar una metodología para ense ar la técnica de el ciclismo mediante la utilización de variables biomecánicas para desarrollar un sistema de feedback visual aumentado (FVA). Fue aplicado en 19 personas sin experiencia en el ciclismo, divididos en dos grupos (experimental = 10 y control = 9). Inicialmente se realizó un pre-test para determinar el consumo máximo de oxígeno (VO2max) y la carga de trabajo utilizada en las sesiones de práctica que correspondía al 60% del VO2máx. El grupo experimental fue sometido a la FVA y el control a la feedback aumentado (FA). El ensayo de retención mostró un aumento del 21% en la media del índice de eficacia (IE) en el grupo experimental en comparación con el grupo control. Los resultados mostraron que las variables biomecánicas son apropiadas para el desarrollo de la FVA y puede contribuir al proceso de ense anza y aprendizaje del ciclismo. The aim of this study was to test a methodology to teach the pedaling technique of cycling using biomechanics variables to develop an augmented visual feedback system (AVF). Nineteen subjects divided in two groups (experimental = 10 and control = 9) without experience in cycling were used. A pre-test was conducted to determine the maximal oxygen uptake (VO2máx) , and to establishe the work load to be used during the learning sessions which was defined to be the load that was associated with the 60% of VO2máx . Seven practice sessions were held. The experimental group was submitted to AVF and the control group to augmented feedback (AF). After the practice sessions, the retenti
Optimal Steady Motions for Oriented Vehicles
William Holderbaum,William Holderbaum
Theoretical Mathematics and Applications , 2013,
Abstract: Motivated by the motion planning problem for oriented vehicles travelling in a 3-Dimensional space; Euclidean space E3 , the sphere S3 and Hyperboloid H3. For such problems the orientation of the vehicle is naturally represented by an orthonormal frame over a point in the underlying manifold. The orthonormal frame bundles of the space forms R3 , S3 and H3 correspond with their isometry groups and are the Euclidean group of motion SE(3), the rotation group SO(4) and the Lorentzian group SO(1,3) respectively. Orthonormal frame bundles of space forms coincide with their isometry groups and therefore the focus shifts to left-invariant control systems defined on Lie groups. In this paper a method for integrating these systems is given where the controls are time-independent. For constant twist motions or helical motions, the corresponding curves g(t) ε SE(3) are given in closed form by using the well known Rodrigues’ formula. However, this formula is only applicable to the Euclidean case. This paper gives a method for computing the non-Euclidean screw/helical motions in closed form. This involves decoupling the system into two lower dimensional systems using the double cover properties of Lie groups, then the lower dimensional systems are solved explicitly in closed form.
Cambio climático regional y turismo local: el caso del sur de Brasil
Holderbaum,Breno Storino;
Estudios y perspectivas en turismo , 2010,
Abstract: the article proposes an analysis of the interrelation between the regional climate changes. at first, some indicators of climate change such as average annual temperature, rainfall, frequency of extreme climatic events, maxima and minimum average temperature were taken into account. then, in order to establish an interrelation between these indications and tourism in southern brazil two tourist micro regions were chosen where there is a close relation between tourism and climate: the mountain range of the state of rio grande do sul and the tourist region of the coast of the state of santa catarina, which are two good examples to illustrate the way the actual climate change can affect tourism.
Cambio climático regional y turismo local: el caso del sur de Brasil Regional Climate Change and Tourism: the Case of Southern Brazil
Breno Storino Holderbaum
Estudios y perspectivas en turismo , 2010,
Abstract: El artículo propone un análisis de la interrelación entre el cambio climático y el turismo en el sur de Brasil. Primeramente se tomaron en cuenta los indicios de este cambio climático a nivel regional por lo que se presentan algunos indicadores anómalos como temperatura media anual, precipitación, frecuencia de eventos climáticos extremos, temperatura media máxima y temperatura media mínima. Luego, con el objeto de establecer una relación con el turismo en el sur de Brasil fueron seleccionadas dos micro-regiones turísticas recayendo la designación en la Sierra del Estado de Río Grande do Sul la y en la costa del estado de Santa Catarina. En ambas se observa una estrecha relación entre turismo y clima, tanto en forma directa como indirecta, lo cual permite mostrar ejemplos concretos de núcleos turísticos afectados por los cambios climáticos regionales. The article proposes an analysis of the interrelation between the regional climate changes. At first, some indicators of climate change such as average annual temperature, rainfall, frequency of extreme climatic events, maxima and minimum average temperature were taken into account. Then, in order to establish an interrelation between these indications and tourism in southern Brazil two tourist micro regions were chosen where there is a close relation between tourism and climate: the mountain range of the state of Rio Grande do Sul and the tourist region of the coast of the state of Santa Catarina, which are two good examples to illustrate the way the actual climate change can affect tourism.
COMPORTAMENTO DAS POPULA ES DE Aphidius sp. (BRACONIDE - HYMENOPTERA) E Brevicoryne brassicae (L., 1778) (APHIDIDAE - HOMOPTERA) EM DIFERENTES CULTIVARES DE REPOLHO EM CONDI ES DE CAMPO BEHAVIOR OF Aphidius sp. (BRACONIDAE-HYMENOPTERA) AND Brevicoryne brassicae (L., 1778) (APHIDIDAE-HOMOPTERA) POPULATIONS ON DIFFERENT CABBAGE CULTIVARS IN FIELD CONDITIONS
Ant?nio Henrique Garcia,Guilherme Porta Cattini
Pesquisa Agropecuária Tropical , 2007, DOI: 10.5216/pat.v25i2.2919
Abstract: Estudou-se o comportamento das popula es de Aphidius sp. e B. brassicae nas cultivares de repolho ‘kobayashi’, ‘roxo’, ‘chato de quintal’, ‘cora o de boi’ e ‘matsukase' em infesta es naturais no campo. As amostragens foram mensais, de agosto a dezembro de 1995, coletando-se de cada folha mais infestada um disco foliar de 6,1 cm2 de área, no ponto de maior concentra o de pulg es. O percentual de parasitismo foi determinado contando-se o número de pulg es mumificados em rela o ao total de cada disco foliar. As cultivares ‘roxo’ e ‘kobayashi’ foram as mais infestadas pelo pulg o, no entanto apresentaram o menor índice de parasitismo por Aphidius sp., com 23,3% e 25% respectivamente, enquanto a ‘cora o de boi’ e ‘chato de quintal’ foram as menos infestadas pelo pulg o, mas apresentaram as maiores popula es do parasitóide, com 51,7 e 67,5% de parasitismo. As menores popula es do pulg o e do parasitóide foram observadas na cultivar ‘matsukase’. As cultivares ‘matsukase’, ‘chato de quintal’ e ‘cora o de boi’ apresentaram altas popula es do pulg o e do parasitóide nos meses de agosto, outubro e novembro. Nas cultivares ‘kobayashi’ e ‘roxo’ houve um crescimento de ambas as popula es até novembro. No geral as maiores popula es de B. brassicae e do Aphidius sp. foram observadas nos meses de agosto, outubro e novembro. O parasitismo em B. brassicae observado em todas as cultivares, foi de 36,3% e o maior índice ,55,8%, foi observado no mês de agosto. PALAVRAS-CHAVE: Parasitismo; Aphidius; Brevicoryne brassicae. The behavior of Aphidius sp. and B. brassicae populations on cabbage cultivars Kobayashi, Roxo, Chato de Quintal, Cora o de Boi and Matsukase were studied in natural field conditions. Monthly samples were collected from August to December 1995. Leaf discs measuring 6.1cm2 were taken from sites showing higher aphid concentration from each most infected leaf. The percentage of parasitized insects was determined by the number of mummified aphids among the total on each leaf disc. Although Roxo and Kobayashi cultivars showed the highest aphid infestation, they were the least parasitized by Aphidius sp., with 23.3% and 25% parasitism, respectively. Cora o de Boi and Chato de Quintal cultivars were the least infested by the aphid, but showed the highest parasitoid populations, as 51.7% and 67.5% respectively. The lower aphid and parasitoid populations were observed on Matsukase cultivar. Chato de Quintal, Cora
On singular probability densities generated by extremal dynamics
Guilherme J. M. Garcia,Ronald Dickman
Physics , 2003, DOI: 10.1016/j.physa.2003.09.047
Abstract: Extremal dynamics is the mechanism that drives the Bak-Sneppen model into a (self-organized) critical state, marked by a singular stationary probability density $p(x)$. With the aim of understanding this phenomenon, we study the BS model and several variants via mean-field theory and simulation. In all cases, we find that $p(x)$ is singular at one or more points, as a consequence of extremal dynamics. Furthermore we show that the extremal barrier $x_i$ always belongs to the `prohibited' interval, in which $p(x)=0$. Our simulations indicate that the Bak-Sneppen universality class is robust with regard to changes in the updating rule: we find the same value for the exponent $\pi$ for all variants. Mean-field theory, which furnishes an exact description for the model on a complete graph, reproduces the character of the probability distribution found in simulations. For the modified processes mean-field theory takes the form of a functional equation for $p(x)$.
On the thresholds, probability densities, and critical exponents of Bak-Sneppen-like models
Guilherme J. M. Garcia,Ronald Dickman
Physics , 2004, DOI: 10.1016/j.physa.2004.04.074
Abstract: We report a simple method to accurately determine the threshold and the exponent $\nu$ of the Bak-Sneppen model and also investigate the BS universality class. For the random-neighbor version of the BS model, we find the threshold $x^*=0.33332(3)$, in agreement with the exact result $x^*=1/3$ given by mean-field theory. For the one-dimensional original model, we find $x^*=0.6672(2)$ in good agreement with the results reported in the literature; for the anisotropic BS model we obtain $x^*=0.7240(1)$. We study the finite size effect $x^*(L)-x^*(L \to \infty) \propto L^{-\nu}$, observed in a system with $L$ sites, and find $\nu = 1.00(1)$ for the random-neighbor version, $\nu = 1.40(1)$ for the original model, and $\nu=1.58(1)$ for the anisotropic case. Finally, we discuss the effect of defining the extremal site as the one which minimizes a general function $f(x)$, instead of simply $f(x)=x$ as in the original updating rule. We emphasize that models with extremal dynamics have singular stationary probability distributions $p(x)$. Our simulations indicate the existence of two symmetry-based universality classes.
Absorbing-state phase transitions with extremal dynamics
Ronald Dickman,Guilherme J. M. Garcia
Physics , 2004, DOI: 10.1103/PhysRevE.71.066113
Abstract: Extremal dynamics represents a path to self-organized criticality in which the order parameter is tuned to a value of zero. The order parameter is associated with a phase transition to an absorbing state. Given a process that exhibits a phase transition to an absorbing state, we define an ``extremal absorbing" process, providing the link to the associated extremal (nonabsorbing) process. Stationary properties of the latter correspond to those at the absorbing-state phase transition in the former. Studying the absorbing version of an extremal dynamics model allows to determine certain critical exponents that are not otherwise accessible. In the case of the Bak-Sneppen (BS) model, the absorbing version is closely related to the "$f$-avalanche" introduced by Paczuski, Maslov and Bak [Phys. Rev. E {\bf 53}, 414 (1996)], or, in spreading simulations to the "BS branching process" also studied by these authors. The corresponding nonextremal process belongs to the directed percolation universality class. We revisit the absorbing BS model, obtaining refined estimates for the threshold and critical exponents in one dimension. We also study an extremal version of the usual contact process, using mean-field theory and simulation. The extremal condition slows the spread of activity and modifies the critical behavior radically, defining an ``extremal directed percolation" universality class of absorbing-state phase transitions. Asymmetric updating is a relevant perturbation for this class, even though it is irrelevant for the corresponding nonextremal class.
Asymmetric dynamics and critical behavior in the Bak-Sneppen model
Guilherme J. M. Garcia,Ronald Dickman
Physics , 2004, DOI: 10.1016/j.physa.2004.04.133
Abstract: We investigate, using mean-field theory and simulation, the effect of asymmetry on the critical behavior and probability density of Bak-Sneppen models. Two kinds of anisotropy are investigated: (i) different numbers of sites to the left and right of the central (minimum) site are updated and (ii) sites to the left and right of the central site are renewed in different ways. Of particular interest is the crossover from symmetric to asymmetric scaling for weakly asymmetric dynamics, and the collapse of data with different numbers of updated sites but the same degree of asymmetry. All non-symmetric rules studied fall, independent of the degree of asymmetry, in the same universality class. Conversely, symmetric variants reproduce the exponents of the original model. Our results confirm the existence of two symmetry-based universality classes for extremal dynamics.
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