Para garimpar mais que ouro - uma análise do desempenho olímpico brasileiro

The Olympic Games are sportive events of global relevance. Here, we perform an analysis of the medal table from a general perspective and of the Brazilian performance over the last 10 competitions, and we show that there is no real improvement of such a performance at all. We then try to understand the relationships among the place in the medal table and social aspects of development. We discuss that there is a physiological basis involved in how elite athletes emerge, but without the proper social investment it wouldn’t be possible to select, in a systematic and wide way, these athletes. It is in this sense, of the type of the investment, that gold medals can have a much greater social meaning to the country.As Olimpíadas são eventos esportivos de relevância mundial. No presente artigo, fazemos uma análise da evolução do quadro geral de medalhas em termos mundiais e do desempenho do Brasil ao longo dos últimos 10 eventos, mostrando que não tem havido melhora de tal desempenho. Procuramos, então, entender e estender as relações entre a colocação no quadro geral e aspectos sociais de desenvolvimento. Discutimos que existe uma base fisiológica envolvida em como despontam atletas de elite, mas que sem o devido investimento social, não há como selecionar, de maneira sistemática e ampla, tais atletas. É neste sentido, do tipo de investimento, que a obtenção do ouro olímpico pode ter um significado muito maior, de cunho social, para o país

To mine more than gold – an analysis of the brazilian olympic \ud performance

As Olimpíadas são eventos esportivos de relevância mundial. No presente artigo, fazemos uma análise da evolução do quadro geral de medalhas em termos mundiais e do desempenho do Brasil ao longo dos últimos 10 eventos, mostrando que não tem havido melhora de tal desempenho. Procuramos, então, entender e estender as relações entre a colocação no quadro geral e aspectos sociais de desenvolvimento. Discutimos que existe uma base fisiológica envolvida em como despontam atletas de elite, mas que sem o devido investimento social, não há como selecionar, de maneira sistemática e ampla, tais atletas. É neste sentido, do tipo de investimento, que a obtenção do ouro olímpico pode ter um significado muito maior, de cunho social, para o país.The Olympic Games are sportive events of global relevance. Here, we perform an analysis of the medal table from a general perspective and of the Brazilian performance over the last 10 competitions, and we show that there is no real improvement of such a performance at all. We then try to understand the relationships among the place in the medal table and social aspects of development. We discuss that there is a physiological basis involved in how elite athletes emerge, but without the proper social investment it wouldn’t be possible to select, in a systematic and wide way, these athletes. It is in this sense, of the type of the investment, that gold medals can have a much greater social meaning to the country

The Scaling of Blood Pressure and Volume

The cardiovascular system is an apparatus of mass convection, and changes in organismic size impart changes in variables of this system, namely scaling effects. Blood flow depends on pressure and conductance, and the maintenance of flow results in entropy production, that is, loss of available work. In terms of scaling, it is well known that blood pressure is kept constant while blood volume varies linearly with body mass. Yet, such expected rules have never been proven. The present study shows that these scaling rules derive from the simultaneous optimization of blood flow and entropy production in circulation and how these impact the transition from ecto- to endotermy. Thus, for the first time in almost a century of data collection, these observed relationships are explained from a theoretical standpoint. The demonstration presented herein is a building block to form a solid basis for the other scaling rules of the cardiovascular system as well as of other organic systems. The approach is of wide interest in any area where generalized flow is analyzed in terms of system optimization, giving a broad perspective on change in either engineered or naturally evolving systems

Entropy Generation and Control: Criteria to Calculate Flow Optimization in Biological Systems

Living beings are composite thermodynamic systems in non-equilibrium conditions. Within this context, there are a number of thermodynamic potential differences (forces) between them and the surroundings, as well as internally. These forces lead to flows, which, ultimately, are essential to life itself, but, at the same time, are associated with entropy generation, i.e., a loss of useful work. The maintenance of homeostatic conditions, the tenet of physiology, demands the regulation of these flows by control of variables. However, due to the very nature of these systems, the regulation of flows and control of variables become entangled in closed loops. Here, we show how to combine entropy generation with respect to a process, and control of parameters (in such a process) in order to create a criterium of optimal ways to regulate changes in flows, the coefficient of flow-entropy (CJσ). We demonstrate the restricted possibility to obtain an increase in flow along with a decrease in entropy generation, and the more general situation of increases in flow along with increases in entropy generation of the process. In this scenario, the CJσ aims to identify the best way to combine the gain in flow and the associated loss of useful work. As an example, we analyze the impact of vaccination effort in the spreading of a contagious disease in a population, showing that the higher the vaccination effort the higher the control over the spreading and the lower the loss of useful work by the society

Energy and time optimization during exit from torpor in vertebrate endotherms

Torpor is used in small sized birds and mammals as an energy conservation trait. Considerable effort has been put towards elucidating the mechanisms underlying its entry and maintenance, but little attention has been paid regarding the exit. Firstly, we demonstrate that the arousal phase has a stereotyped dynamic: there is a sharp increase in metabolic rate followed by an increase in body temperature and, then, a damped oscillation in body temperature and metabolism. Moreover, the metabolic peak is around two-fold greater than the corresponding euthermic resting metabolic rate. We then hypothesized that either time or energy could be crucial variables to this event and constructed a model from a collection of first principles of physiology, control engineering and thermodynamics. From the model, we show that the stereotyped pattern of the arousal is a solution to save both time and energy. We extended the analysis to the scaling of the use of torpor by endotherms and show that variables related to the control system of body temperature emerge as relevant to the arousal dynamics. In this sense, the stereotyped dynamics of the arousal phase necessitates a certain profile of these variables which is not maintained as body size increases

Temperature effects on a whole metabolic reaction cannot be inferred from its components.

Changes in temperature affect the kinetic energy of the constituents of a system at the molecular level and have pervasive effects on the physiology of the whole organism. A mechanistic link between these levels of organization has been assumed and made explicit through the use of values of organismal Q10 to infer control of metabolic rate. To be valid this postulate requires linearity and independence of the isolated reaction steps, assumptions not accepted by all. We address this controversy by applying dynamic systems theory and metabolic control analysis to a metabolic pathway model. It is shown that temperature effects on isolated steps cannot rigorously be extrapolated to higher levels of organization

Bouts of exercise elicit discordant testosterone: cortisol ratios in runners and non-runners

ABSTRACT Objective: The testosterone:cortisol ratio (T:C) is suggested to be used in order to examine whether physical exercise generates either a “catabolic environment” or an “anabolic environment”. The present study aims to evaluate the acute time-course profile of cortisol and testosterone due to an episode of physical exercise. A biphasic profile in the T:C ratio response was hypothesized. Materials and methods: Morning sessions of treadmill running at two different intensities (Heart Rate at 65% and 80% of the maximum cardiac reserve) were performed by 6 male non-runners (NR) and 12 trained male runners (subdivided into trained runners T1 and T2). Cortisol and testosterone were measured in saliva. NR and T1 ran for 30 minutes at both intensities, and T2 ran for 46 minutes (± 4.1) at 65% and 42 minutes (± 3.5) at 80%. Results: In the 80% heart rate target, both groups of runners showed the biphasic time-profile, while the non-runners group did not. However, at the 65% level, none of the groups presented the hypothesized biphasic response. Conclusions: A biphasic time-profile in the testosterone:cortisol ratio can be seen in short-bout, high intensity exercise (treadmill running) during the morning in men trained for this specific physical activity