An analysis of a regular black hole interior model

We analyze the thermodynamical properties of the regular static and spherically symmetric black hole interior model presented by Mboyne and Kazanas. Equations for the thermodynamical quantities valid for an arbitrary density profile are deduced, and from them we show that the model is thermodynamically unstable. Evidence is also presented pointing to its dynamical instability. The gravitational entropy of this solution based on the Weyl curvature conjecture is calculated, following the recipe given by Rudjord, Gr$\varnothing$n and Sigbj$\varnothing$rn, and it is shown to have the expected behavior.Comment: 22 pages, 17 figures, accepted for publication in International Journal of Theoretical Physic

Gravitational entropy of black holes and wormholes

Pure thermodynamical considerations to describe the entropic evolution of the universe seem to violate the Second Law of Thermodynamics. This suggests that the gravitational field itself has entropy. In this paper we expand recent work done by Rudjord, Gr{\O}n and Sigbj{\O}rn where they suggested a method to calculate the gravitational entropy in black holes based on the so-called `Weyl curvature conjecture'. We study the formulation of an estimator for the gravitational entropy of Reissner-Nordstr\"om, Kerr, Kerr-Newman black holes, and a simple case of wormhole. We calculate in each case the entropy for both horizons and the interior entropy density. Then, we analyse whether the functions obtained have the expected behaviour for an appropriate description of the gravitational entropy density.Comment: 11 pages, 11 figures, accepted for publication in International Journal of Theoretical Physic

An analysis of a regular black hole interior model

We analyze the thermodynamical properties of the regular static and spherically symmetric black hole interior model presented by Mbonye and Kazanas. Equations for the thermodynamical quantities valid for an arbitrary density profile are deduced, and from them we show that the model is thermodynamically unstable. Evidence is also presented pointing to its dynamical instability. The gravitational entropy of this solution based on the Weyl curvature conjecture is calculated, following the recipe given by Rudjord, Grøn and Sigbjørn, and it is shown to have the expected behavior.Facultad de Ciencias Astronómicas y Geofísica

Efficiency, equality and reciprocity in social preferences: A comparison of students and a representative population.

The debate between Engelmann and Strobel (2004, 2006) and Fehr, Naef, and Schmidt (2006) highlights the important question of the extent to which lab experiments on student populations can serve to identify the motivational forces present in society at large. We address this question by comparing the lab behavior of a student group and a non-student group, where the non-student group on all observable factors is almost identical to the representative adult population in Norway. All participants take part in exactly the same lab experiment. Our study shows that students may not be informative of the role of social preferences in the broader population. We nd that the representative participants differ fundamentally from students both in their level of selfishness and in the relative importance assigned to different moral motives. It is also interesting to note that while we do not find any substantial gender differences among the students, males and females in the representative group differ fundamentally in their moral motivation.Representative sample; Social preferences; Laboratory experiment.

Los consejeros de Castilla : eruditos y escritores (1759-1788)

En este artículo estudio la actividad intelectual de los consejeros de Castilla durante el reinado de Carlos III, en concreto, su formación erudita como escritores. Con ello continuo la línea de investigación comenzada por Janine Fayard quien en su excelente monografía sobre los consejeros de Castilla refleja numerosos datos acerca de sus vidas: lugar de nacimiento, formación universitaria como colegiales o manteístas, cursus administrativo antes y después de acceder al Consejo de Castilla, familias con las que emparentan, bienes que dejan en sus testamentos, etc. que confirman la importancia de este cargo en la administración del Antiguo Régimen.In this article, I study the intellectual activity of the Castilian counsellors during Carlos III's reign, exactly, their erudite education as writers. Along with that, I continue my research line started by Janine Fayard who, in her excellent monograph about the Castilian counsellors, reflect several data about their lives: birthplace, academic formation as collegian or "manteístas", administrative cursus (before and after taking part in the Consejo de Castilla), families to whom the become related by marriage, goods left in their wills, and so on, which confirm the importance of his charge in the Ancient Regime administration

Diet overlap between North-East Arctic cod and haddock in the southern part of the Barents Sea in 1984-1986

The diet composition of North-East Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are examined from stomach content data. Fish were collected in the southern part of the Barents Sea from 1984 to 1986. A total of 4790 cods and 1361 haddocks were divided according to season (winter, spring and fall) and fish size in 10 cm size classes. Only fish bigger than 10 cm length were considered. Diet overlap between the two species for each size group in each season was calculated using the Schoener's index. North-East Arctic cod show a size dependent shift in the diet. Fish smaller than 20 cm prey mainly on crustaceans (euphauiids, deep sea shrimp and amphipods). Above 20 cm, cod incorporate fish in the diet to a larger degree, the degree increasing with the size of the predator. Some seasonal changes are described. Haddock, a less ichthiophagous, bivalves and polychaetes. In general the diet overlap is low except in spring and fall when the smaller size groups of both species prey on euphausiids. The results are compared with previous information on cod-haddock interaction

Critical response of elastic-plastic SDOF systems with nonlinear viscous damping under simulated earthquake ground motions

Multi impulse with constant time interval is used as a representative of a long-duration earthquake ground motion. An analytical expression is derived for the elastic-plastic response of a single-degree-of-freedom (SDOF) model with nonlinear viscous damping subjected to the “critical multi impulse” which maximizes the response. The fact that only free vibration appears under such multi impulse enables the smart application of an energy approach in deriving the analytical expression for a complicated elastic-plastic response with nonlinear viscous damping. The nonlinear viscous damping characteristic for deformation is approximated in terms of a quadratic or elliptical function. The critical timing of the impulses is found to correspond to the zero restoring-force timing or the maximum velocity timing depending on the input level. It is shown that the nonlinearity in viscous damping causes a remarkable influence on the earthquake response in some cases. The reliability and accuracy of the proposed theory are investigated through the comparison with the results by the time-history response analysis to the tuned sine wave as a representative of the long-duration earthquake ground motion

An analysis of a regular black hole interior

In this work we address the issue of the thermodynamic behavior of a non-singular spherically-symmetric black hole model introduced by Mbonye and Kanzanas (2005). This spacetime is described by Schwarschild's solution at large radius and by a de Sitter-like solution at small radius. The interior of the black hole consists of matter fields with sound speed bounded by the speed of light. The matter transits smoothly between normal matter and a core of an exotic fluid with an equation of state that approaches p = -ρ when r → 0. We derive the general equations of the thermodynamic quantities for an arbitrary matter density profile, and adjust the results to the specific regular black hole. We also calculate the Weyl and Kretschmann scalars and analyse the behaviour of the gravitational field in connection with the thermodynamics of the matter fields. Finally, we study whether the regular behaviour at the center affects the thermodynamics of the black hole, and we discuss a possible physical interpretation of the state of regular black hole interiors.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Immoral criminals? An experimental study of social preferences among prisoners.

This paper studies the pro-social preferences of criminals by comparing the behavior of a group of prisoners in a lab experiment with the behavior of a benchmark group recruited from the general population. We find a striking similarity in the importance the two groups attach to pro-social preferences in both in strategic and non-strategic situations. This result also holds when the two groups interact. Data from a large internet experiment,matched with official criminal records, suggest that our main finding from the lab experiment is not influenced by the additional scrutiny experienced by participants in prison.Pro-social preferences; Criminals; Lab experiment

Diet overlap between North-East Arctic cod and haddock in the southern part of the Barents Sea in 1984-1986

The diet composition of North-East Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are examined from stomach content data. Fish were collected in the southern part of the Barents Sea from 1984 to 1986. A total of 4790 cods and 1361 haddocks were divided according to season (winter, spring and fall) and fish size in 10 cm size classes. Only fish bigger than 10 cm length were considered. Diet overlap between the two species for each size group in each season was calculated using the Schoener's index. North-East Arctic cod show a size dependent shift in the diet. Fish smaller than 20 cm prey mainly on crustaceans (euphauiids, deep sea shrimp and amphipods). Above 20 cm, cod incorporate fish in the diet to a larger degree, the degree increasing with the size of the predator. Some seasonal changes are described. Haddock, a less ichthiophagous, bivalves and polychaetes. In general the diet overlap is low except in spring and fall when the smaller size groups of both species prey on euphausiids. The results are compared with previous information on cod-haddock interaction