An accurate formula for the period of a simple pendulum oscillating beyond the small-angle regime

A simple approximation formula is derived here for the dependence of the period of a simple pendulum on amplitude that only requires a pocket calculator and furnishes an error of less than 0.25% with respect to the exact period. It is shown that this formula describes the increase of the pendulum period with amplitude better than other simple formulas found in literature. A good agreement with experimental data for a low air-resistance pendulum is also verified and it suggests, together with the current availability/precision of timers and detectors, that the proposed formula is useful for extending the pendulum experiment beyond the usual small-angle oscillations.Comment: 15 pages and 4 figures. to appear in American Journal of Physic

Uma nova abordagem para diagnóstico de doenças via web.

RESUMO: Neste trabalho é apresentada e discutida a nova plataforma do módulo de diagnóstico de doenças (módulo produtor) do sistema Diagnose Virtual que foi desenvolvida para integrar ao portal WebAgritec. O WebAgritec é uma plataforma, concretizada na forma de um website com uma interface mais interativa para transferência das tecnologias da Embrapa para os extensionistas e produtores rurais. Esta plataforma, baseada nos conceitos de Web 2.0, visa o planejamento, previsão e monitoramento da produção agrícola e reúne informações sobre as culturas de arroz, feijão, milho, soja e trigo.SBIAgro 2011

Sistema Diagnose Virtual: módulo produtor: manual do usuário

O sistema Diagnose Virtual é um ambiente virtual na WEB para diagnóstico de doenças de plantas e enfermidades de animais que se utiliza de mecanismos de inferência (investigação) aplicados sobre o conhecimento de especialistas previamente categorizado. Este documento tem por objetivo orientar o usuário do sistema Diagnose Virtual no procedimento para sua utilização visando obter resultados corretos com menor esforço. O sistema é também dotado de ajuda online, na qual cada funcionalidade do sistema é descrita de forma sucinta mostrada desde que o ponteiro do mouse fique parado por um instante em cima da funcionalidade. Outra forma de ajuda pode ser obtida a cada tela, clicando o símbolo de interrogação no canto inferior direito. O documento aborda o módulo do usuário/produtor, no qual são exploradas as características de um problema (um caso) de uma determinada cultura até obter-se o diagnóstico. Como resultados são fornecidas as possíveis desordens com seus respectivos graus de certeza.bitstream/item/11858/1/doc85.pd

The role of background music in the visitors’ experience of art exhibition: music, memory, and art appraisal

This study explores the effect of background music on the perception and memory of an art exhibition in two experiments involving art evaluation, memory and behavioural intentions. The first (N = 234), a laboratory experiment conducted in a virtual art gallery, shows that background music helps people remember artworks but negatively influences evaluation of them in terms of arousal, valence and liking. The second (N = 238), a field experiment conducted in seven art galleries, shows that the gallery experience facilitates behavioural intentions through the mediation of positive emotions and memory; background music again acts as an ambivalent stimulus, as it amplifies the link between memory and behavioural intentions while attenuating the link between pleasant arousal (i.e., the emotional evaluation component) and behavioural intentions. This study contributes to the literature by investigating an under-researched subject (experiencing art). It shows that, contrary to the results reported in the literature, music may have adverse effects. It also expands the stimulus-organism-response model by introducing memory into atmospheric research on music. Art galleries can benefit from the favourable effects of music, but the music needs to match the style of the artwork so that its stimulus does not overlap that of the art.info:eu-repo/semantics/acceptedVersio

Numerical Simulation of Magnetic Interactions in Polycrystalline YFeO3

The magnetic behavior of polycrystalline yttrium orthoferrite was studied from the experimental and theoretical points of view. Magnetization measurements up to 170 kOe were carried out on a single-phase YFeO3 sample synthesized from heterobimetallic alkoxides. The complex interplay between weak-ferromagnetic and antiferromagnetic interactions, observed in the experimental M(H) curves, was successfully simulated by locally minimizing the magnetic energy of two interacting Fe sublattices. The resulting values of exchange field (H_E = 5590 kOe), anisotropy field (H_A = 0.5 kOe) and Dzyaloshinsky-Moriya antisymmetric field (H_D = 149 kOe) are in good agreement with previous reports on this system.Comment: 26 pages, 9 figure