Revisiting 2D numerical models for the 19th century outbursts of eta Carinae

We present here new results of two-dimensional hydrodynamical simulations of the eruptive events of the 1840s (the great) and the 1890s (the minor) eruptions suffered by the massive star eta Carinae (Car). The two bipolar nebulae commonly known as the Homunculus and the little Homunculus (LH) were formed from the interaction of these eruptive events with the underlying stellar wind. We assume here an interacting, non-spherical multiple-phase wind scenario to explain the shape and the kinematics of both Homunculi, but adopt a more realistic parametrization of the phases of the wind. During the 1890s eruptive event, the outflow speed decreased for a short period of time. This fact suggests that the LH is formed when the eruption ends, from the impact of the post-outburst eta Car wind (that follows the 1890s event) with the eruptive flow (rather than by the collision of the eruptive flow with the pre-outburst wind, as claimed in previous models; Gonzalez et al.). Our simulations reproduce quite well the shape and the observed expansion speed of the large Homunculus. The LH (which is embedded within the large Homunculus) becomes Rayleigh-Taylor unstable and develop filamentary structures that resemble the spatial features observed in the polar caps. In addition, we find that the interior cavity between the two Homunculi is partially filled by material that is expelled during the decades following the great eruption. This result may be connected with the observed double-shell structure in the polar lobes of the eta Car nebula. Finally, as in previous work, we find the formation of tenuous, equatorial, high-speed features that seem to be related to the observed equatorial skirt of eta Car.

The perception of accessibility in Web development by academy, industry and government: a survey of the Brazilian scenario

Accessibility has become a serious issue to be considered by various sectors of the society. However, what are the differences between the perception of accessibility by academy, government and industry? In this paper, we present an analysis of this issue based on a large survey carried out with 613 participants involved with Web development, from all of the 27 Brazilian states. The paper presents results from the data analysis for each sector, along with statistical tests regarding the main different issues related to each of the sectors, such as: government and law, industry and techniques, academy and education. The concern about accessibility law is poor even amongst people from government sector. The analyses have also pointed out that the academy has not been addressing accessibility training accordingly. The knowledge about proper techniques to produce accessible contents is better than other sectors`, but still limited in industry. Stronger investments in training and in the promotion of consciousness about the law may be pointed as the most important tools to help a more effective policy on Web accessibility in Brazil.