Tilted boxes on inclined planes

We propose the study of a box placed on an inclined plane, with an initial tilt with respect to the plane. This is a paradigmatic example of the role played by friction as a link between translational and rotational motion. This example has two advantages over the usual example of a sphere (or cylinder) rolling down an inclined plane. First, it provides a good model for a much greater variety of "real-life" situations. Second, it exhibits a much richer structure in parameter space, even when the box starts from rest. (C) 2000 American Association of Physics Teachers.

O poder e a moda vestimentar

Nas mutações da moda, sendo também Influenciadas por acontecimentos políticos e espirituais, é a acção condicionante de certos indivíduos que é determinante. Limitando-se ao campo do vestuário, investigação das interferências, proporcionais à força dos regimes, do poder sobre a moda, tanto pela lei como pelo exemplo; desde a corte do Duque de Borgonha às legislações sumptuárias e ao caso paradigmático de Luís XIV, até à China de Mao, referindo casos da sociedade portuguesa. ABSTRACT - Mutations in fashion are influenced by the action of certain people. The research is limited to the field of clothing, the connections between power and fashion, both by law and by example, from the court of the Duke of Burgundy to the laws that restraint luxury, and the paradigmatic study cases of Louis XIV and the China under the rule of Mao Tse Tung. Some cases of the Portuguese society are also referred.

Word learning and text organisation: an intervention case

In the present study we focus on the interaction between the acquisition of new words and text organisation. In the acquisition of new words we emphasise the acquisition of paradigmatic relations such as hyponymy, meronymy and semantic sets. We work with a group of girls attending a private school for adolescents in serious difficulties. The subjects are from disadvantaged families. Their writing skills were very poor. When asked to describe a garden, they write a short text of a single paragraph, the lexical items were generic, there were no adjectives, and all of them use mainly existential verbs. The intervention plan assumed that subjects must to be exposed to new words, working out its meaning. In presence of referents subjects were taught new words making explicit the intended relation of the new term to a term already known. In the classroom subjects were asked to write all the words they knew drawing the relationships among them. They talk about the words specifying the relation making explicit pragmatic directions like is a kind of, is a part of or are all x. After that subjects were exposed to the task of choosing perspective. The work presented in this paper accounts for significant differences in the text of the subjects before and after the intervention. While working new words subjects were organising their lexicon and learning to present a whole entity in perspective.

On the analytical solutions of the Hindmarsh-Rose neuronal model

In this article we analytically solve the Hindmarsh-Rose model (Proc R Soc Lond B221:87-102, 1984) by means of a technique developed for strongly nonlinear problems-the step homotopy analysis method. This analytical algorithm, based on a modification of the standard homotopy analysis method, allows us to obtain a one-parameter family of explicit series solutions for the studied neuronal model. The Hindmarsh-Rose system represents a paradigmatic example of models developed to qualitatively reproduce the electrical activity of cell membranes. By using the homotopy solutions, we investigate the dynamical effect of two chosen biologically meaningful bifurcation parameters: the injected current I and the parameter r, representing the ratio of time scales between spiking (fast dynamics) and resting (slow dynamics). The auxiliary parameter involved in the analytical method provides us with an elegant way to ensure convergent series solutions of the neuronal model. Our analytical results are found to be in excellent agreement with the numerical simulations.

Óbidos, literary village: innovation in the creative industries?

The village of Óbidos was recognized in 2015 as a creative city in the area of literature, becoming a member of the UNESCO Creative Cities Network. The attribution of the title depends on the fulfillment of a number of criteria the regions have to integrate. In addition to Óbidos, UNESCO attributed the same title in the same year to other European cities, including Barcelona, Nottingham, Ljubljana, Tartu and Lviv. This article intends to co nduct a case study to the cultural and artistic offer, as well as the cultural and literary legacy that different cities provide to be able to inquire the innovation of the proposals. The study aims to assess how much Óbidos, compared to other cities with the same title, is creative. Knowing that the concept of creative city (Landry and Bianchini, 1995) results from the emergence of new technologies and a new type of economy based on creativity and innovation and that creativity implies removing economic or social value of the creative work or talent, the study aims to determine to what extent the processes generated gave rise to new ideas (creativity) and what processes led to its implementation (innovation). Being innovation in the creative industries asso ciated with product, process, positioning, paradigmatic and social innovation (Storsul and Krumsvik, 2013), it is concluded that, in Óbidos, the entrepreneurship initiatives are more focused on tourists who occasionally visit the village and the business o pportunities that are generated there. New innovative and creative spaces were created, promoting literature and adding value and quality to urban space. This urban intervention resulted in the attraction of individuals who streamlined new habits of being and acting in the village