Colour-Magnitude Diagrams of candidate age-gap filling LMC clusters

The LMC has a rich star cluster system spanning a wide range of ages and masses. One striking feature of the LMC cluster system is the existence of an age gap between 3-10 Gyrs. Four LMC clusters whose integrated colours are consistent with those of intermediate age simple stellar populations have been imaged with the Optical Imager (SOI) at the Southern Telescope for Astrophysical Research (SOAR). Their colour-magnitude diagrams (CMDs) reach V ~ 24. Isochrone fits, based on Padova evolutionary models, were carried out to these CMDs, after subtraction of field contamination. The preliminary results are as follows: KMK88-38 has an age of ~ 1.3 Gyr, assuming typical LMC metallicity and distance modulus, and a very low redenning. For OGLE-LMC0531, the best eye fits to isochrones yield an age ~ 1.6 Gyr and E(B-V)=0.03. BSDL917 is younger, ~ 150 yrs, and subjected to larger extinction (E(B-V)=0.08). The remaining cluster is currently under analysis. Therefore, we conclude that these clusers are unlikely to fill in the LMC cluster age gap, even when fitting uncertainties in the parameters are considered.Comment: 4 pages, 5 figures, compact form of the poster published online in the proceedings of IAUS256: The Magellanic System: Stars, Gas, and Galaxie

On the self-consistent physical parameters of LMC intermediate-age clusters

The LMC clusters are unique templates of simple stellar population (SSP), being crucial to calibrate models describing the integral light as well as to test the stellar evolution theory. With this in mind we analyzed HST/WFPC2 (V, B--V) colour-magnitude diagrams (CMDs) of 15 populous LMC clusters with ages between ~0.3 Gyr and ~4 Gyr using different stellar evolutionary models (Padova, PEL or Pisa, BaSTI or Teramo). Following the approach described by Kerber, Santiago & Brocato (2007), we determined accurate and self-consistent physical parameters (age, metallicity, distance modulus and reddening) for each cluster by comparing the observed CMDs with synthetic ones. We found significant trends in the physical parameters due to the choice of stellar evolutionary model and treatment of convective core overshooting. In general, models that incorporate overshooting presented more reliable results than those that do not. Comparisons with the results found in the literature demonstrated that our derived metallicities are in good agreement with the ones from the spectroscopy of red giants. We also confirmed that, independent of the adopted stellar evolutionary library, the recovered 3D distribution for these clusters is consistent with a thick disk roughly aligned with the LMC disk as defined by field stars. Finally, we also provide new estimates of distance modulus to the LMC center, that are marginally consistent with the canonical value of 18.50.Comment: 6 pages, 4 figures, conference contribution to IAU Symposium 256, van Loon J.T. & Oliviera J.M., ed

The white dwarf cooling sequence of 47 Tucanae

47 Tucanae is one of the most interesting and well observed and theoretically studied globular clusters. This allows us to study the reliability of our understanding of white dwarf cooling sequences, to confront different methods to determine its age, and to assess other important characteristics, like its star formation history. Here we present a population synthesis study of the cooling sequence of the globular cluster 47 Tucanae. In particular, we study the distribution of effective temperatures, the shape of the color-magnitude diagram, and the corresponding magnitude and color distributions. We do so using an up-to-date population synthesis code based on Monte Carlo techniques, that incorporates the most recent and reliable cooling sequences and an accurate modeling of the observational biases. We find a good agreement between our theoretical models and the observed data. Thus, our study, rules out previous claims that there are still missing physics in the white dwarf cooling models at moderately high effective temperatures. We also derive the age of the cluster using the termination of the cooling sequence, obtaining a good agreement with the age determinations using the main-sequence turn-off. Finally, we find that the star formation history of the cluster is compatible with that btained using main sequence stars, which predict the existence of two distinct populations. We conclude that a correct modeling of the white dwarf population of globular clusters, used in combination with the number counts of main sequence stars provides an unique tool to model the properties of globular clusters.Comment: 6 pages and 4 figures accepted for publication in A &

Circadian and Metabolic Effects of Light: Implications in Weight Homeostasis and Health

Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus (SCN) and peripheral circadian oscillators regulate physiology and metabolism to set temporal variations in homeostatic regulation. Phase coherence of these circadian oscillators is achieved by the entrainment of the SCN to the environmental 24-h light:dark (LD) cycle, coupled through downstream neural, neuroendocrine, and autonomic outputs. The SCN coordinate activity and feeding rhythms, thus setting the timing of food intake, energy expenditure, thermogenesis, and active and basal metabolism. In this work, we will discuss evidences exploring the impact of different photic entrainment conditions on energy metabolism. The steady-state interaction between the LD cycle and the SCN is essential for health and wellbeing, as its chronic misalignment disrupts the circadian organization at different levels. For instance, in nocturnal rodents, non-24 h protocols (i.e., LD cycles of different durations, or chronic jet-lag simulations) might generate forced desynchronization of oscillators from the behavioral to the metabolic level. Even seemingly subtle photic manipulations, as the exposure to a "dim light" scotophase, might lead to similar alterations. The daily amount of light integrated by the clock (i.e., the photophase duration) strongly regulates energy metabolism in photoperiodic species. Removing LD cycles under either constant light or darkness, which are routine protocols in chronobiology, can also affect metabolism, and the same happens with disrupted LD cycles (like shiftwork of jetlag) and artificial light at night in humans. A profound knowledge of the photic and metabolic inputs to the clock, as well as its endocrine and autonomic outputs to peripheral oscillators driving energy metabolism, will help us to understand and alleviate circadian health alterations including cardiometabolic diseases, diabetes, and obesity.Fil: Plano, Santiago Andrés. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Moro, Paula. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Self-consistent physical parameters for MC clusters from CMD modelling: application to SMC clusters observed with the SOAR telescope

The Magellanic Clouds (MCs) present a rich system of stellar clusters that can be used to probe the dynamical and chemical evolution of these neighboring and interacting irregular galaxies. In particular, these stellar clusters (SCs) present combinations of age and metallicity that are not found for this class of objects in the Milky Way, being therefore very useful templates to test and to calibrate integrated light simple stellar population (SSP) models applied to unresolved distance galaxies. On its turn, the age and metallicity for a cluster can be determined spatially resolving its stars, by means of analysis of its colour-magnitude diagrams (CMDs). In this work we present our method to determine self-consistent physical parameters (age, metallicity, distance modulus and reddening) for a stellar cluster, from CMDs modelling of relatively unstudied SCs in the Small Magellanic Cloud (SMC) imaged in the BVI filters with the 4.1 m SOAR telescope. Our preliminary results confirm our expectations that come from a previous integrated spectra and colour analysis: at least one of them (Lindsay 2) is an intermediate-age stellar cluster with ~ 2.6 Gyr and [Fe/H] ~ -1.3, being therefore a new interesting witness regarding the reactivation of the star formation in the MCs in the last 4 Gyr.Comment: 4 pages, 2 figures. To be published in the proceedings of IAUS256: The Magellanic System: Stars, Gas, and Galaxie

The Napoleonic Wars: A Watershed in Spanish History?

The Napoleonic Wars had dramatic consequences for Spain's economy. The Peninsular War had higher demographic impact than any other military conflict, including civil wars, in the modern era. Farmers suffered confiscation of their crops and destruction of their main capital asset, livestock. The shrinking demand, the disruption of international and domestic trade, and the shortage of inputs hampered industry and services. The loss of the American colonies, a by-product of the French invasion, seriously harmed absolutism. In the long run, however, the Napoleonic Wars triggered the dismantling of Ancien Régime institutions and interest groups. Freed from their constraints, the country started a long and painful transition towards the liberal society. The Napoleonic Wars may be deemed, then, a watershed in Spanish history

Fenômeno Juliette: inspirações e reflexões sobre os atributos humanos de um influenciador disruptivo

Este trabalho de pesquisa apresentou uma análise dos seis atributos humanos que geram influência a partir das categorias descritas no livro “Leaders Without Titles” de Stephen J. Sampson (2011): Beleza, Inteligência, Sociabilidade, Emocionalidade, Personalidade, Integridade. Estas características serviram de base para a construção de um questionário com 29 questões abertas e fechadas aplicado a 268 seguidores de Juliette Freire, vencedora do reality show Big Brother Brasil 2021, com o objetivo de entender quais atributos humanos de influência são percebidos por eles e que, portanto, tornaram Juliette uma influenciadora disruptiva. Para tanto, analisou-se quali e quantitativa as características de influência apresentadas por Sampson (2011), juntamente com os conceitos de marketing e marketing de influência. Constatou-se que atributos ligados com “fazer a coisa certa” e ter humildade, mantendo conexão direta e humanizada com os seus seguidores, tais como integridade, emocionalidade e sociabilidade apresentaram um nível alto de concordância entre os respondentes. Concluiu-se que o perfil de Juliette é disruptivo, porque ela apresenta valores sociais consistentes e que esses atributos a fizeram quebrar os padrões apresentados por outros influenciadores

Excesso de adiposidade corporal periférica, central e geral em adolescentes: associação com diferentes contextos de atividade física

TCC (Graduação) - Universidade Federal de Santa Catarina. Centro de Desportos. Educação Física - Bacharelado.Fatores individuais modificáveis do estilo de vida, como a atividade física e hábitos saudáveis apresentam-se como os mais próximos dos profissionais de Educação Física quanto à orientação de como prevenir o excesso de adiposidade. Diferentes contextos de atividade física cercam os adolescentes e entender como se relacionam com a distribuição de adiposidade periférica, central e geral pode ser oportuno para identificação dos grupos de risco e o planejamento de intervenções de combate ao sobrepeso e a obesidade por meio do estímulo da prática regular de atividade física. Portanto, o objetivo deste estudo foi analisar a associação de diferentes contextos de atividade física (aulas de Educação Física, recreio escolar, deslocamento, tempo de lazer e participação em equipe esportiva) com a adiposidade periférica, central e geral em adolescentes estudantes do ensino médio de uma cidade no Sul do Brasil. Estudo transversal com a participação de 1.132 adolescentes (14-19 anos) de ambos os sexos, do município de São José, Santa Catarina. As variáveis dependentes foram a adiposidade periférica obtida por meio da dobra cutâneas do tríceps, adiposidade central investigada por meio da dobra cutânea subescapular e foram classificadas em elevadas a partir do percentil 90 da distribuição de referência do Centers for Disease Control and Prevention. A adiposidade geral foi investigada pela combinação das dobras cutâneas tricipital e subescapular e considerada elevada quando estavam acima do percentil 90, simultaneamente. Os diferentes contextos da atividade física foram investigados por meio de questionário autorreferido. As variáveis de controle foram idade, nível econômico, turno de estudo e maturação sexual. Foi empregada a regressão logística binária com nível de significância p<0,05. As prevalências de excesso de adiposidade periférica, central e geral foram 43,4%, 61,5% e 39,2%, respectivamente, para os adolescentes do sexo masculino e 56,6%, 38,5% e 60,8%, respectivamente para o sexo feminino. As adolescentes do sexo feminino durante o recreio escolar apresentaram maiores chances de ter excesso de adiposidade periférica (OR: 1,53; IC95%: 0,39; 0,85) e os adolescentes do sexo masculino inativos no tempo de lazer apresentaram maiores chances de ter excesso de adiposidade periférica (OR: 3,10; IC95%: 1,56; 6,13) central (OR: 2,38; IC95%: 1,08; 5,26) e geral (OR: 2,25; IC95%: 1,17; 4,50). Portando, conclui-se que adolescentes do sexo feminino apresentaram maiores prevalências de excesso de adiposidade periférica quando inativas durante o recreio escolar. O sexo masculino inativo no lazer apresentou maiores chances de excesso de adiposidade periférica, central e geral

White dwarf constraints on a varying GG

A secular variation of $G$ modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code, an up-to-date pulsational code, and a detailed population synthesis code we demonstrate that the effects of a running $G$ are obvious both in the properties of individual white dwarfs, and in those of the white dwarf populations in clusters. Specifically, we show that the white dwarf evolutionary sequences depend on both the value of $\dot G/G$, and on the value of $G$ when the white dwarf was born. We show as well that the pulsational properties of variable white dwarfs can be used to constrain $\dot G/G$. Finally, we also show that the ensemble properties of of white dwarfs in clusters can also be used to set upper bounds to $\dot G/G$. Precisely, the tightest bound --- $\dot G/G \sim -1.8 10^{-12}$ yr$^{-1}$ --- is obtained studying the population of the old, metal-rich, well populated, open cluster NGC 6791. Less stringent upper limits can be obtained comparing the theoretical results obtained taking into account the effects of a running $G$ with the measured rates of change of the periods of two well studied pulsating white dwarfs, G117--B15A and R548. Using these white dwarfs we obtain $\dot G/G\sim -1.8\times 10^{-10}$ yr$^{-1}$, and $\dot G/G\sim -1.3\times 10^{-10}$ yr$^{-1}$, respectively, which although less restrictive than the previous bound, can be improved measuring the rate of change of the period of massive white dwarfs.Comment: 6 pages, 3 figures. To be published in the proceedings of the conference "Varying fundamental constants and dynamical dark energy" (8 - 13 July 2013, Sexten Center for Astrophysics