Regular black holes in f(G)f(G) gravity

In this work, we study the possibility of generalizing solutions of regular black holes with an electric charge, constructed in general relativity, for the $f(G)$ theory, where $G$ is the Gauss-Bonnet invariant. This type of solution arises due to the coupling between gravitational theory and nonlinear electrodynamics. We construct the formalism in terms of a mass function and it results in different gravitational and electromagnetic theories for which mass function. The electric field of these solutions are always regular and the strong energy condition is violated in some region inside the event horizon. For some solutions, we get an analytical form for the $f(G)$ function. Imposing the limit of some constant going to zero in the $f(G)$ function we recovered the linear case, making the general relativity a particular case.Comment: 22 pages, 25 figures.Version published in EPJ

Equilibrium dynamics in two-sector models of endogenous growth

This paper presents an account of the dynamics of endogenous growth models with physical capital and human capital. We consider some important extensions of the basic framework of Lucas (1988) and Uzawa (1964), including physical capital in the human capital technology and leisure activities as an additional argument of agents' welfare

A two-sector model of endogenous growth with leisure

In this paper we analyze a class of endogenous growth models with physical and human capital and with three altematives uses of time: unqualified leisure, work and education. In contrast to some other related models, we find that, even in the absence of technological extemalities, there could be multiple balanced paths. We provide a characterization of the qualitative behavior of consumption, leísure, work and education over those balanced paths, and study their transitional dynamics

Equilibrium dynamics in two-sector models of endogenous growth.

This paper presents an account of the dynamics of endogenous growth models with physical capital and human capital. We consider some important extensions of the basic framework of Lucas (1988) and Uzawa (1964), including physical capital in the human capital technology and leisure activities as an additional argument of agents' welfare.Endogenous growth; Physical capital; Human capital; Long-term growth; Transitional dynamics;

A two-sector model of endogenous growth with leisure.

In this paper we analyze a class of endogenous growth models with physical and human capital and with three altematives uses of time: unqualified leisure, work and education. In contrast to some other related models, we find that, even in the absence of technological extemalities, there could be multiple balanced paths. We provide a characterization of the qualitative behavior of consumption, leísure, work and education over those balanced paths, and study their transitional dynamics.

Stable isotopes reveal differences in diet among reed bunting subspecies that vary in bill size

Reed bunting Emberiza schoeniclus subspecies vary considerably in bill size and shape and seem to be at an early stage of speciation, in which bill might be indirectly causing reproductive isolation. Hence, we evaluated whether bill size, as well as age and sex, are associated with foraging niche in three west European subspecies of reed bunting: the thin-billed schoeniclus, the intermediate-billed lusitanica and the thick-billed witherbyi. Blood sampling was undertaken at three sites in southwest Europe during the winter (when these subspecies co-occur), and stable isotope analyses (carbon and nitrogen) were performed to assess their foraging niches. Stable isotope analyses of potential food items confirmed uniform baseline isotopic composition among sites. schoeniclus showed a significantly broader isotopic niche than lusitanica and witherbyi, which seemed otherwise similar despite the fact that witherbyi is more divergent in bill traits. Stable isotope ratios were consistent with the latter two subspecies feeding on C3-plant-feeding insects, whereas schoeniclus diet also included C4 plant material. Despite its lower sexual dimorphism, sex and age differences were found only in schoeniclus, but these differences vary between locations in a complex manner. Our results suggest that bill size and shape differentiated between northern, migratory and southern, resident subspecies as a consequence of natural selection through competition during the winter, which is now reflected in isotopic niche divergence between subspecies. The potential roles of sexual selection, reed thickness and summer temperature on the difference in bill size (and greater sexual dimorphism) between lusitanica and witherbyi are discussed