Comparing metrics at large: harmonic vs quo-harmonic coordinates

To compare two space-times on large domains, and in particular the global structure of their manifolds, requires using identical frames of reference and associated coordinate conditions. In this paper we use and compare two classes of time-like congruences and corresponding adapted coordinates: the harmonic and quo-harmonic classes. Besides the intrinsic definition and some of their intrinsic properties and differences we consider with some detail their differences at the level of the linearized approximation of the field equations. The hard part of this paper is an explicit and general determination of the harmonic and quo-harmonic coordinates adapted to the stationary character of three well-know metrics, Schwarzschild's, Curzon's and Kerr's, to order five of their asymptotic expansions. It also contains some relevant remarks on such problems as defining the multipoles of vacuum solutions or matching interior and exterior solutions.Comment: 27 pages, no figure

Ethical communication and intercultural responsibility: a philosophical perspective

The ethical dimension of dialogue represents a major concern in the context of current research in intercultural responsibility. In this paper, I discuss the modalities in which the notion of competence is used to conceptualise responsibility and the relationship between self and other in intercultural research, in order to critique the Cartesian presuppositions of intercultural communication theory. I argue that models of competence and responsibility that are employed to design intercultural training operate within the paradigm of the autonomous rational agent that informs Kantian ethical thinking. I contrast the model of the competent intercultural speaker that emerges in intercultural research with the distinction proposed by Levinas between the saying and the said (le dire and le dit, meaning the event of speech and the content of speech), to suggest two scenarios of intercultural interaction that show two different approaches to responsibility, one operating in the dimension of the said and the other in the dimension of the saying. Thus, in this paper, I discuss the implications of Levinas's reflection on the nature of language for the development of an ethical framework that addresses the limitations of current conceptualisations in intercultural communication theory of competence and responsibility

Adubação da soja: VI - Efeitos do enxôfre e de vários micronutrientes (Zn, Cu, B, Mn, Fe e Mo), em solo Latosol Roxo com vegetação de cerrado Fertilizing soybeans: VI- Effects of sulfur and some micro-nutrients in a latosol soil with "cerrado" vegetation

Os efeitos do enxôfre e dos micronutrientes estudados (zinco, cobre, boro, manganês, ferro e molibdênio) sôbre a produção da soja foram testados em uma área de Latosol Roxo com vegetação de cerrado. O enxôfre, quer adicionado, sob a forma de gêsso, a superfosfato triplo, quer veiculado por superfosfato simples, proporcionou substanciais e significativos aumentos de produção, ao passo que as respostas aos micronutrientes foram pequenas e não significativas.<br>The responses of soybeans to sulfur, zinc, copper, boron, manganese, iron and molybdenum were tested in an area of latosol soil previously covered with "cerrado" vegetation. Sulfur increased considerably the seed yield, but no significant effects of the indicated micro-nutrients were observed