A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

Efeitos dos exercícios resistidos sobre o equilíbrio e a funcionalidade de idosos saudáveis: artigo de atualização Effects of resistance training on balance and functional ability in healthy elderly: an update

A diminuição da força muscular com o envelhecimento e os baixos níveis de atividade física contribuem para défices funcionais e de equilíbrio. Esta revisão sistemática teve como objetivo analisar os estudos que correlacionaram o treino resistido (TR) isolado, o equilíbrio e a função de idosos saudáveis. A busca nas bases do Google Acadêmico e na BVS levou à seleção de 35 estudos controlados. O TR isolado mostrou ser relevante para a função dos idosos (90% dos estudos) devido sobretudo ao ganho de força e mobilidade. Exercícios de baixa e moderada intensidade tiveram melhores resultados sobre a função de idosas, frágeis e sedentários. Em relação ao equilíbrio, apesar da inconsistência dos dados, o TR parece exercer efeitos positivos, sobretudo devido a fatores neuromusculares. Estudos com parâmetros de treino e amostra uniformes são necessários para melhor comparação dos resultados, sobretudo em idosos com padrão funcional elevado.<br>Muscle strength decrease in aging and low physical activity levels may be an indicator of balance deficits and functional limitations. The purpose of this systematic review was to assess the effects of resistance training (RT) alone on balance performance and functional capacity in healthy elderly. The search in Google Scholar and BVS led to selecting 35 controlled trials. The RT alone showed to have positive effects (90% of the studies) on functional tasks in elderly, associated with increases in strength and mobility. Moderate and low-intensity exercise could produce functional capacity benefits in older women, frail and sedentary elderly. Despite the inconsistency of data, resistance training appears to exert positive effects on balance, especially through neuromuscular factors. Standardization of methodology and homogeneity of sampling may ensure greater comparability of results, especially among elderly with high physical functional level