840 research outputs found
Nonequilibrium corrections in the pressure tensor due to an energy flux
The physical interpretation of the nonequilibrium corrections in the pressure
tensor for radiation submitted to an energy flux obtained in some previous
works is revisited. Such pressure tensor is shown to describe a moving
equilibrium system but not a real nonequilibrium situation.Comment: 4 pages, REVTeX, Brief Report to appear in PRE Dec 9
Variational Principles for Stellar Structure
The four equations of stellar structure are reformulated as two alternate
pairs of variational principles. Different thermodynamic representations lead
to the same hydromechanical equations, but the thermal equations require, not
the entropy, but the temperature as the thermal field variable. Our treatment
emphasizes the hydrostatic energy and the entropy production rate of luminosity
produced and transported. The conceptual and calculational advantages of
integral over differential formulations of stellar structure are discussed
along with the difficulties in describing stellar chemical evolution by
variational principles.Comment: 28 pages, LaTeX, requires AASTeX, 1 PostScript figure, revisions:
erratum; accepted by Astrophysical Journa
Information theory in the study of anisotropic radiation
Information theory is used to perform a thermodynamic study of non
equilibrium anisotropic radiation. We limit our analysis to a second-order
truncation of the moments, obtaining a distribution function which leads to a
natural closure of the hierarchy of radiative transfer equations in the
so-called variable Eddington factor scheme. Some Eddington factors appearing in
the literature can be recovered as particular cases of our two-parameter
Eddington factor. We focus our attention in the study of the thermodynamic
properties of such systems and relate it to recent nonequilibrium thermodynamic
theories. Finally we comment the possibility of introducing a nonequilibrium
chemical potential for photons.Comment: 1 eps figure upon request by e-mail, to appear in Journal of Physics
The Balloon Analog Insurance Task (BAIT): A Behavioral Measure of Protective Risk Management
Prior methods used to assess individual differences related to risk have not focused on an important component of risk management: how willing individuals are to pay for or take actions to insure what they already have. It is not clear whether this type of protective risk management taps into the same individual differences as does risk taking propensity measured by existing risk taking tasks. We developed a novel task to assess protective risk management, the Balloon Analog Insurance Task (BAIT), which is modeled after the Balloon Analog Risk Task (BART). In the BAIT, individuals are forced to decide how much money they are willing to pay in order to insure a specific fraction of their prior winnings given changing but imprecise levels of risk of monetary loss. Participants completed the BART and BAIT for real monetary rewards, and completed six self report questionnaires. The amount of insurance purchased on the BAIT was positively correlated with scores on the Intolerance of Uncertainty Scale and on the Checking scale of the revised Obsessive Compulsive Inventory. Conversely, the amount of insurance purchased was negatively correlated with scores on the Domain Specific Risk Taking Questionnaire, and on the Psychopathic Personality Inventory (PPI). Furthermore, relationships between insurance purchased and these scales remained significant after controlling for the BART in linear regression analyses, and the BART was only a significant predictor for measures on one scale - the PPI. Our results reveal that behavior on the BAIT taps into a number of individual differences that are not related to behavior on another measure of risk taking. We propose that the BAIT may provide a useful complement to the BART in the assessment of risk management style
Consuming Lines of Difference: The Politics of Wealth and Poverty along the Color Line
Commentators on African American life have often focused on poverty, evaded African American wealth, and ignored the ways genteel affluence and impoverishment were constructed along turn-of-the-century color lines. Documentary research and archaeology at the Madam CJ Walker home in Indianapolis, Indiana illuminates how the continuum of wealth and poverty was defined and negotiated by one of African America’s wealthiest early 20th century entrepreneurs. The project provides an opportunity to compare the ways in which wealth was defined and experienced along the color line in the early 20th century and how such
notions of Black affluence shaped racialized definitions of poverty and materialit
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