Some dynamical properties of a classical dissipative bouncing ball model with two nonlinearities

Some dynamical properties for a bouncing ball model are studied. We show that when dissipation is introduced the structure of the phase space is changed and attractors appear. Increasing the amount of dissipation, the edges of the basins of attraction of an attracting fixed point touch the chaotic attractor. Consequently the chaotic attractor and its basin of attraction are destroyed given place to a transient described by a power law with exponent -2. The parameter-space is also studied and we show that it presents a rich structure with infinite self-similar structures of shrimp-shape. © 2013 Elsevier B.V. All rights reserved.

Measuring the effects of manipulating stimulus presentation time on sensorimotor alpha and low beta reactivity during hand movement observation

The present study addresses three methodological questions that have been ignored in previous research on EEG indices of the human mirror neuron system (hMNS), particularly in regard to autistic individuals. The first question regards how to elicit the EEG indexed hMNS during movement observation: Is hMNS activation best elicited using long stimulus presentations or multiple short repetitions? The second question regards what EEG sensorimotor frequency bands reflect sensorimotor reactivity during hand movement observation? The third question regards how widespread is the EEG reactivity over the sensorimotor cortex during movement observation? The present study explored sensorimotor alpha and low beta reactivity during hand movement versus static hand or bouncing balls observation and compared two experimental protocols (long exposure vs. multiple repetitions) in the same participants. Results using the multiple repetitions protocol indicated a greater low beta desynchronisation over the sensorimotor cortex during hand movement compared to static hand and bouncing balls observation. This result was not achieved using the long exposure protocol. Therefore, the present study suggests that the multiple repetitions protocol is a more robust protocol to use when exploring the sensorimotor reactivity induced by hand action observation. In addition, sensorimotor low beta desynchronisation was differently modulated during hand movement, static hand and bouncing balls observation (non-biological motion) while it was not the case for sensorimotor alpha and that suggest that low beta may be a more sensitive index of hMNS activation during biological motion observation. In conclusion the present study indicates that sensorimotor reactivity of low beta during hand movement observation was found to be more widespread over the sensorimotor cortex than previously thought.

Clearing the cloudy crystal balls: Hybrid modelling for energy and climate change mitigation scenarios – A case study for Portugal

Dissertação para obtenção do Grau de Doutor em Ambiente

On the Properties and Cosmology of Q-balls

The properties and cosmological importance of a class of non-topological solitons, Q-balls, are studied. Aspects of Q-ball solutions and Q-ball cosmology discussed in the literature are reviewed. Q-balls are particularly considered in the Minimal Supersymmetric Standard Model with supersymmetry broken by a hidden sector mechanism mediated by either gravity or gauge interactions. Q-ball profiles, charge-energy relations and evaporation rates for realistic Q-ball profiles are calculated for general polynomial potentials and for the gravity mediated scenario. In all of the cases, the evaporation rates are found to increase with decreasing charge. Q-ball collisions are studied by numerical means in the two supersymmetry breaking scenarios. It is noted that the collision processes can be divided into three types: fusion, charge transfer and elastic scattering. Cross-sections are calculated for the different types of processes in the different scenarios. The formation of Q-balls from the fragmentation of the Aflieck-Dine -condensate is studied by numerical and analytical means. The charge distribution is found to depend strongly on the initial energy-charge ratio of the condensate. The final state is typically noted to consist of Q- and anti-Q-balls in a state of maximum entropy. By studying the relaxation of excited Q-balls the rate at which excess energy can be emitted is calculated in the gravity mediated scenario. The Q-ball is also found to withstand excess energy well without significant charge loss. The possible cosmological consequences of these Q-ball properties are discussed.

Bouncing Back, Recovery of Fish Productions, 2003

Water fact sheet for Iowa Department of Natural Resources and the Geological Bureau.

Ritme i expressió, balls i danses del món aplicades a l'àmbit escolar. 'Ritmo y expresión, bailes y danzas del mundo aplicadas al ámbito escolar'.

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Bouncing and bending light.

Diseñado para introducir temas científicos de forma accesible, se centra en cómo viaja la luz, cómo se forman sombras y por qué se produce la reflexión y refracción de la luz. Ofrece experimentos que demuestran la reflexión, refracción, interferencia, y la dispersión de la luz por espejos, lentes, y otros materiales.

La festa, memòria col·lectiva d’un poble. Cançons, balls i tonades de Manacor: un recurs a l’aula

Les manifestacions musicals dels actes festius de Manacor són el principal objecte d’estudi d’aquest treball, que pretén unir tres mons: la música i cultura tradicionals, la pedagogia i les noves tecnologies de la informació i la comunicació. Per entendre bé el significat de les cançons, balls i tonades que hem estudiat i organitzat seguint la roda de l’any, hem hagut d’endinsar-nos en les arrels de la nostra història i cultura per poder-les contextualitzar. El fil conductor han estat les festes populars, que guarden gran part de la memòria col·lectiva d’un poble. Hem afavorit l’ús pedagògic mitjançant fitxes d’anàlisi, aplicacions didàctiques i enregistraments de les cançons seleccionades, tot confiant que pugin servir de recurs per a qualsevol docent amb l’objectiu d’aprendre música i cultura tradicionals de Manacor i, per extensió, de les Illes Balears. La necessitat de facilitar el maneig del material que oferim en aquest treball i la voluntat de donar-li difusió han fet que prengués forma de pàgina web. Així, tota la informació —marc historicocultural, fitxes i enregistraments— està organitzada en format de web.

November 2001: Scryers, Crystal Balls, and the Future

http://digitalcommons.winthrop.edu/dacusfocus/1016/thumbnail.jpg

Performance comparisons of the kicking of stationary and rolling balls in a futsal context

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Scaling properties of the regular dynamics for a dissipative bouncing ball model

Some scaling properties of the regular dynamics for a dissipative version of the one-dimensional Fermi accelerator model are studied. The dynamics of the model is given in terms of a two-dimensional nonlinear area contracting map. Our results show that the velocities of saddle fixed points (saddle velocities) can be described using scaling arguments for different values of the control parameter. (c) 2007 Elsevier B.V. All rights reserved.

The Feigenbaum's delta for a high dissipative bouncing ball model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)