Comparing Regional Cultures Within a Country: Lessons From Brazil

In this joint article we test the common assumption that a measure of culture developed for the national level can also be used for comparing regions within a country. Three different research projects independently measured culture differences within the Federal Republic of Brazil, all three using a version of Hofstede`s Values Survey Module (VSM). The largest provided separate scores for all of Brazil`s 27 states, the next largest for 17 of the more populous states. Factor analyses of VSM item scores across states in both cases only very partly replicated Hofstede`s cross-national dimension structure; only Individualism versus Collectivism reappeared clearly. We attribute this lack of fit to a restriction of range of VSM item scores among states within a common Brazilian national culture. The item scores did show a cultural clustering of states that fairly closely followed the administrative division of the country into five regions. The culture profiles for these regions show remarkable differences between the Northeast with its Afro-Brazilian roots and the North with its native Indian roots. On the issue of comparing regional cultures, we found the VSM, based on global differences, too coarse a net for catching the finer cultural nuances between Brazilian states. Adding locally defined items would have made the studies more meaningful to Brazilians.

Field dependent transition to the non-linear regime in magnetic hyperthermia experiments: Comparison between maghemite, copper, zinc, nickel and cobalt ferrite nanoparticles of similar sizes

Further advances in magnetic hyperthermia might be limited by biological constraints, such as using sufficiently low frequencies and low field amplitudes to inhibit harmful eddy currents inside the patient's body. These incite the need to optimize the heating efficiency of the nanoparticles, referred to as the specific absorption rate (SAR). Among the several properties currently under research, one of particular importance is the transition from the linear to the non-linear regime that takes place as the field amplitude is increased, an aspect where the magnetic anisotropy is expected to play a fundamental role. In this paper we investigate the heating properties of cobalt ferrite and maghemite nanoparticles under the influence of a 500 kHz sinusoidal magnetic field with varying amplitude, up to 134 Oe. The particles were characterized by TEM, XRD, FMR and VSM, from which most relevant morphological, structural and magnetic properties were inferred. Both materials have similar size distributions and saturation magnetization, but strikingly different magnetic anisotropies. From magnetic hyperthermia experiments we found that, while at low fields maghemite is the best nanomaterial for hyperthermia applications, above a critical field, close to the transition from the linear to the non-linear regime, cobalt ferrite becomes more efficient. The results were also analyzed with respect to the energy conversion efficiency and compared with dynamic hysteresis simulations. Additional analysis with nickel, zinc and copper-ferrite nanoparticles of similar sizes confirmed the importance of the magnetic anisotropy and the damping factor. Further, the analysis of the characterization parameters suggested core-shell nanostructures, probably due to a surface passivation process during the nanoparticle synthesis. Finally, we discussed the effect of particle-particle interactions and its consequences, in particular regarding discrepancies between estimated parameters and expected theoretical predictions. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi. org/10.1063/1.4739533]