Evolution of the ISM of Starburst galaxies: the SN heating efficiency

The interstellar medium heated by SN explosions may acquire an expansion velocity larger than the escape velocity and leave the galaxy through a supersonic wind. SN ejecta are transported out of the galaxies by such winds which thus affect the chemical evolution of the galaxies. The effectiveness of the processes mentioned above depends on the heating efficiency (HE) of the SNe, that is a matter of debate. We have constructed a simple semi-analytic model, considering the essential ingredients of a SB environment which is able to qualitatively trace the thermalisation history of the ISM in a SB region and determine the HE evolution. We find that, as long as the mass-loss rate of the clouds remains larger than the rate at which the SNRs interact one with each other, the SN heating efficiency remains very small, as radiative cooling of the gas dominates. We conclude that the HE value has a time-dependent trend that is sensitive to the initial conditions of the system.Comment: 17 pages, 18 figures, A&A accepte

A vision of Macau’s football through the symbolic legacy of the Portuguese presence

This paper analyses the sociocultural background, and the nature of the cultural legacy of the Portuguese, in the diffusion and promotion of football in Macau. The paper seeks to examine why men’s football in Macau’s remains poorly developed at domestic, regional and international levels. Many factors could explain this lack of development, ranging from the limited degree of organizational specialization inherited from the Portuguese administration, problems regarding implementing rules and tournament organization, the lack of sports facilities, and the tension between the national governing body and the national team athletes. Nevertheless, there has also been some important progress, such as the recruitment of young footballers and the inclusion of local Portuguese talented players. These developments are discussed in a multidisciplinary approach, based on academic literature and harnessing comprehensive documentary analysis derived from official documents and website information of sports associations.info:eu-repo/semantics/acceptedVersio

An intercultural sporting event as part of soft power strategy: Macao’s 1st Lusophony Games

The instrumental impact of sport has experienced an increasing complexity, especially in its relations between society and culture, economy, and politics. The study focused on the Macao Lusophony Games, an intercultural sports event that aims to strengthen ties with Portuguese-speaking countries, or Lusophony. Based on a literature review in interrelated fields such as cultural heritage, language, legacy effects, and soft power, a qualitative approach was undertaken, informed by empirical material from various textual sources. The evidence shows that the Games created ties based on linguistic and cultural reciprocity, expressed as a soft power resource as well as Macao’s realignment within the Lusophone world, as an international political strategy that benefits China’s economic development.info:eu-repo/semantics/publishedVersio

Multidimensional Hydrodynamical Simulations of radiative cooling SNRs-clouds interactions: an application to Starburst Environments

In this work we are interested to study the by-products of SNR-clouds in a starburst (SB) system. These interactions can have an important role in the recycling of matter from the clouds to the ISM and vice-versa. In the present work, we have focused our attention on the global effects of the interactions between clouds and SN shock waves in the ISM of SB environments, and performed 3-D radiative cooling hydrodynamical simulations with the adaptive YGUAZU grid code. We have also considered the effects of the photo-evaporation due to the presence of a high number of UV photons from hot stars and supernovae (SNe). The results have shown that, in the presence of radiative cooling, instead of an efficient gas mixing with the diffuse ISM, the interactions cause the fragmentation of the clouds into smaller ones. The results have also revealed that the SNR-clouds interactions are less efficient at producing substantial mass loss from the clouds to the diffuse ISM than mechanisms such as the photo-evaporation caused by the UV flux from the hot stars.Comment: 15 pages, 25 figures. Figures with higher resolution at the page: http://www.astro.iag.usp.br/~dalpino/ Astronomy & Astrophysics accepte

On the Influence of Magnetic Fields on the Structure of Protostellar Jets

We here present the first results of fully three-dimensional (3-D) MHD simulations of radiative cooling pulsed (time-variable) jets for a set of parameters which are suitable for protostellar outflows. Considering different initial magnetic field topologies in approximate $equipartition$ with the thermal gas, i.e., (i) a longitudinal, and (ii) a helical field, both of which permeating the jet and the ambient medium; and (iii) a purely toroidal field permeating only the jet, we find that the overall morphology of the pulsed jet is not very much affected by the presence of the different magnetic field geometries in comparison to a nonmagnetic calculation. Instead, the magnetic fields tend to affect essentially the detailed structure and emission properties behind the shocks at the head and at the pulse-induced internal knots, particularly for the helical and toroidal geometries. In these cases, we find, for example, that the $H_\alpha$ emissivity behind the internal knots can be about three to four times larger than that of the purely hydrodynamical jet. We also find that some features, like the nose cones that often develop at the jet head in 2-D calculations involving toroidal magnetic fields, are smoothed out or absent in the 3-D calculations.Comment: 13 pages, 3 figures, Accepted by ApJ Letters after minor corrections (for high resolution figures, see http://www.iagusp.usp.br/~adriano/h.tar

The precession of the giant HH34 outflow: a possible jet deceleration mechanism

The giant jets represent a fundamental trace of the historical evolution of the outflow activity over timescales which are comparable to the accretion time of the outflow sources in their main protostellar phase. The study of such huge jets provides the possibility of retrieving important elements related to the life of the outflow sources. In this paper, we study the role of precession (combined with jet velocity-variability and the resulting enhanced interaction with the surrounding environment) as a deceleration mechanism for giant jets using a numerical approach. We obtain predictions of H alpha intensity maps and position-velocity diagrams from 3D simulations of the giant HH 34 jet (including an appropriate ejection velocity time-variability and a precession of the outflow axis), and we compare them with previously published observations of this object. Our simulations represent a step forward from previous numerical studies of HH objects, in that the use of a 7-level, binary adaptive grid has allowed us to compute models which appropiately cover all relevant scales of a giant jet, from the ~ 100 AU jet radius close to the source to the ~ 1 pc length of the outflow. A good qualitative and quantitative agreement is found between the model predictions and the observations. Moreover, we show that a critical parameter for obtaining a better or worse agreement with the observations is the ratio rho_j/rho_a between the jet and the environmental densities. The implications of this result in the context of the current star formation models are discussed (ABRIDGED).Comment: 19 pages, 8 eps figs.,uses aaspp4; accepted by the Ap

Professional football in Portugal: preparing to resume after the COVID-19 pandemic

This article offers a theoretical reflection on how the First Portuguese Football League is preparing to return to competition, after the suspension and mandatory confinement, as well as the security measures adopted in response to the pandemic caused by the new coronavirus. Despite the paper is descriptive and theoretical, our discussion draws particularly on the documentary analysis of mass media/journalist reports, official almanacs, and academic works. The first purpose of this paper, therefore, is to address the way in which professional football is financially exposed and vulnerable to the main sponsors, who seek to exert power and influence. Second, we seek to explore the increasing asymmetrical power relations of the broadcaster’s rights that are increasingly using strategies for wielding power than act a business partner. The implications arising from the study are considered for sport-governing bodies and clubs, in addition to future research directions.info:eu-repo/semantics/publishedVersio