Patterns of Inter-Chromosomal Gene Conversion on the Male-Specific Region of the Human Y Chromosome

The male-specific region of the human Y chromosome (MSY) is characterized by the lack of meiotic recombination and it has long been considered an evolutionary independent region of the human genome. In recent years, however, the idea that human MSY did not have an independent evolutionary history begun to emerge with the discovery that inter-chromosomal gene conversion (ICGC) can modulate the genetic diversity of some portions of this genomic region. Despite the study of the dynamics of this molecular mechanism in humans is still in its infancy, some peculiar features and consequences of it can be summarized. The main effect of ICGC is to increase the allelic diversity of MSY by generating a significant excess of clustered single nucleotide polymorphisms (SNPs) (defined as groups of two or more SNPs occurring in close proximity and on the same branch of the Y phylogeny). On the human MSY, 13 inter-chromosomal gene conversion hotspots (GCHs) have been identified so far, involving donor sequences mainly from the X-chromosome and, to a lesser extent, from autosomes. Most of the GCHs are evolutionary conserved and overlap with regions involved in aberrant X-Y crossing-over. This review mainly focuses on the dynamics and the current knowledge concerning the recombinational landscape of the human MSY in the form of ICGC, on how this molecular mechanism may influence the evolution of the MSY, and on how it could affect the information enclosed within a genomic region which, until recently, appeared to be an evolutionary independent unit

Does graph disclosure bias reduce the cost of equity?

Research on disclosure and capital markets focuses primarily on the amount of information provided but pays little attention to the presentation format of this information. This paper examines the impact of graph utilization and graph quality (distortion) on the cost of equity capital, controlling for the interaction between disclosure and graph distortion. Despite the advantages of graphs in communicating information, our results show that graph utilization does not have a significant impact on users’ decisions. However we observe a significant (negative) association between graph distortion and the exante cost of equity. This effect though, disappears if we use realised returns as a measure of expost cost of equity. Moreover, we find that disclosure and graph distortion interact so that the impact of disclosure on the cost of capital depends on graph integrity. For low level of overall disclosure, graph distortion reduces the exante cost of equity. However for high level of disclosure graph distortion increases the exante cost of equity.

Disclosure and liquidity

The purpose of this paper is to test empirically the relationship between two important concepts: disclosure and liquidity. Using a sample of Spanish quoted firms between 1994 and 2000 we show that the estimation of the relationship between disclosure and liquidity depends crucially on two factors: a) the multidimensionality of the concept of liquidity; b) the use of an econometric methodology that deals properly with the features of the sample used. However the use of the Amihud (2002) illiquidity measure provides evidence in favour of a positive relationship between disclosure and liquidity

DISCLOSURE AND LIQUIDITY

The purpose of this paper is to test empirically the relationship between two important concepts: disclosure and liquidity. Using a sample of Spanish quoted firms between 1994 and 2000 we show that the estimation of the relationship between disclosure and liquidity depends crucially on two factors: a) the multidimensionality of the concept of liquidity; b) the use of an econometric methodology that deals properly with the features of the sample used. However the use of the Amihud (2002) illiquidity measure provides evidence in favour of a positive relationship between disclosure and liquidity.

Adjustment curves for binary responses associated to stochastic processes

Functional Data, Random Multiplicative Cascade, Adjustment Curve, Stochastic Process

O(N)O(N) model in Euclidean de Sitter space: beyond the leading infrared approximation

We consider an $O(N)$ scalar field model with quartic interaction in $d$-dimensional Euclidean de Sitter space. In order to avoid the problems of the standard perturbative calculations for light and massless fields, we generalize to the $O(N)$ theory a systematic method introduced previously for a single field, which treats the zero modes exactly and the nonzero modes perturbatively. We compute the two-point functions taking into account not only the leading infrared contribution, coming from the self-interaction of the zero modes, but also corrections due to the interaction of the ultraviolet modes. For the model defined in the corresponding Lorentzian de Sitter spacetime, we obtain the two-point functions by analytical continuation. We point out that a partial resummation of the leading secular terms (which necessarily involves nonzero modes) is required to obtain a decay at large distances for massless fields. We implement this resummation along with a systematic double expansion in an effective coupling constant $\sqrt\lambda$ and in 1/N. We explicitly perform the calculation up to the next-to-next-to-leading order in $\sqrt\lambda$ and up to next-to-leading order in 1/N. The results reduce to those known in the leading infrared approximation. We also show that they coincide with the ones obtained directly in Lorentzian de Sitter spacetime in the large N limit, provided the same renormalization scheme is used.Comment: 31 pages, 5 figures. Minor changes. Published versio

Movilidad de ingresos y movimientos demográficos en América Latina

In this paper, we contribute to the study of short run income mobility in Latin America by assessing the importance of demographic movements in household income fluctuations. We exploit the rotating scheme of household surveys from seven Latin American countries to build short panels that allow us to quantify the size and relevance of household compositional changes in yearly time windows. We find evidence of a small but significant weight of demographic movements as an explicative factor of short-term income mobility. Additionally, we explore the existence of household strategies to smooth the evolution of per capita income as a response to demographic shocks, consisting of entrance to or exit from the labor market.En este trabajo contribuimos al estudio de la movilidad de ingresos de corto plazo en América Latina computando la importancia de los movimientos demográficos en las fluctuaciones del ingreso familiar. Explotando el esquema rotativo de las encuestas de hogares de siete países latinoamericanos, construimos paneles cortos que permiten cuantificar el tamaño y relevancia de los cambios de composición de los hogares en ventanas temporales anuales. Encontramos evidencia de un peso pequeño pero significativo de los movimientos demográficos como factor explicativo de la movilidad de ingresos en el corto plazo. Adicionalmente, exploramos la existencia de estrategias de los hogares para suavizar la evolución de su ingreso per cápita ante movimientos demográficos que se pueden interpretar como shocks exógeno

Lifshitz scalar fields: one loop renormalization in curved backgrounds

We consider an interacting Lifshitz field with z=3 in a curved spacetime. We analyze the renormalizability of the theory for interactions of the form lambda phi^n, with arbitrary even n. We compute the running of the coupling constants both in the ultraviolet and infrared regimes. We show that the Lorentz violating terms generate couplings to the spacetime metric that are not invariant under general coordinate transformations. These couplings are not suppressed by the scale of Lorentz violation and therefore survive at low energies. We point out that in these theories, unless the effective mass of the field is many orders of magnitude below the scale of Lorentz violation, the coupling to the four dimensional Ricci scalar xi (4)R phi^2 does not receive large quantum corrections xi >> 1.Comment: 17 pages. Minor changes. Published versio