Energy balance and cancers

Energy balance results from the exact equilibrium between caloric intake and caloric expenditure. A caloric intake larger than caloric expenditure results in overweight, even obesity, but other determinants, like hormonal dysfunction and/or genetic traits may play a part in obesity syndrome. Obesity, and even overweight, have been recognized as risk factors for the development of cancers. Human epidemiological studies, which have tended to establish the nature of the relationship between energy balance and cancer, are summarized first, with the influence of the various factors which act both on obesity and on cancer risk. Among these factors are the macronutrients responsible for the caloric intake, and some lifestyle factors (physical activity, drinking habits and tobacco use). Second, the animal studies help to distinguish between different relevant factors, and to understand some of the underlying mechanisms. However, the insulin-resistance syndrome, which appears to underlie the relationship between obesity and hormone-dependent cancers, and possibly colon cancer, is only relevant to human physiology because hormonal alterations are part of it. Prevention of hyperinsulinemia, insulin resistance and the accompanying visceral obesity appears to be a major public health task for the prevention of cancers

Energy-balance in stream-flows carrying suspended load

Problem.-— The mechanism by which a flowing fluid transports solid material in suspension has received a great deal of thought. Many avenues of approach have been explored in attempts to gain more insight into the phenomenon. One of these which has been employed with the object of establishing the basic criteria of transportation in suspension has been the study of the energy-balance of the flow. The Transactions of the American Geophysical Union contain important discussions that fall in this category. In 1933, W. W. Rubey [Trans, 1933, p. 497] presented a paper on “Equilibrium-conditions in debris-laden streams” to the Section of Hydrology. This article proposes a general expression of stream-equilibrium in the form of an energy-equation. In this equation the loss in potential-energy of the flowing mixture plus the decrease in kinetic energy of flow is equated to the energy consumed in friction plus the energy consumed in supporting the debris. One of the significant conclusions reached by Rubey on the basis of this analysis, together with pertinent field-data, is that the energy consumed in supporting the debris is normally a very small fraction of the total energy in the flow

Energy-balance climate models

An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed

The global energy balance of Titan

The global energy budget of planets and their moons is a critical factor to influence the climate change on these objects. Here we report the first measurement of the global emitted power of Titan. Long-term (2004–2010) observations conducted by the Composite Infrared Spectrometer (CIRS) onboard Cassini reveal that the total emitted power by Titan is (2.84 ± 0.01) × 10^(14) watts. Together with previous measurements of the global absorbed solar power of Titan, the CIRS measurements indicate that the global energy budget of Titan is in equilibrium within measurement error. The uncertainty in the absorbed solar energy places an upper limit on the energy imbalance of 6.0%

Mechanisms of Energy Balance in Obesity

The proper understanding of obesity requires a multifaceted approach. Behavioral considerations of eating and activity patterns do not account for the large between- and within-subjects variance associated with the energy-balance equation. Sources of adaptive and dispositional variance in metabolic rates are reviewed and suggested to be a likely source of importance for the proper conceptualization and intervention of obesity. Five proposed mechanisms of metabolic variation are reviewed with consideration of the supporting evidence for each mechanism. The generalizability of some of the proposed mechanisms is limited because of the scope of past research. However, the roles of lipoprotein lipase in fat storage and brown adipose tissue in thermogenesis are intriguing possibilities for future research with humans

Energy balance of cosmic rays

Energy dissipation channels of cosmic rays in galaxy and metagalax