The early evolutionary history of neo-sex chromosomes in Neotropical grasshoppers, Boliviacris noroestensis (Orthoptera: Acrididae: Melanoplinae)

Neo-sex chromosomes are an important component of chromosome variation in Orthoptera, particularly South American Melanoplinae species, which have proven to be outstanding experimental model system to study the mechanism of sex chromosome evolution in this group of insects. In terms of their origin, most derived sex chromosome mechanisms involve a Robertsonian fusion (i.e. translocation) between the ancestral X chromosome and an autosome. In the grasshopper, Boliviacris noroestensis Ronderos & Cigliano (1990) (Orthoptera: Acrididae: Melanoplinae), our results point to a small degree of differentiation (conserved homology between the XR arm and the neo-Y) of the neo-XY chromosomes, which may be of recent evolutionary origin. However, a simple centric fusion model does not explain their origin, mainly because of the observed reduction in the fundamental number (FN) of arms. We propose two models which, we hope, clarify the genesis of B. noroestensis neo-sex chromosomes. Records of karyotype variation in related species due to multiple rearrangements support our models. We propose a possible adaptive advantage for neo-sex chromosome carriers, such changes perhaps representing the primary force that increases their frequency within natural populations compared with non-fused translocated forms, and occurring without apparent detriment to the microevolutionary forces that may also act, at least at the beginning of the evolutionary history of individuals bearing such neo-sex chromosomes.Fil: Castillo, Elio Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Taffarel, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Accountability and corruption : political institutions matter

Using a cross-country panel, Lederman, Loayza, and Soares examine the determinants of corruption, paying particular attention to political institutions that increase political accountability. Previous empirical studies have not analyzed the role of political institutions, even though both the political science and the theoretical economics literature have indicated their importance in determining corruption. The main theoretical hypothesis guiding the authors?empirical investigation is that political institutions affect corruption through two channels: political accountability and the structure of the provision of public goods. The results suggest that political institutions are extremely important in determining the prevalence of corruption: democracy, parliamentary systems, political stability, and freedom of the press are all associated with lower corruption. In addition, the authors show that common findings of the earlier empirical literature on the determinants of corruption?elated to openness and legal tradition?o not hold once political variables are taken into account.Corruption&Anitcorruption Law,Decentralization,Pharmaceuticals&Pharmacoeconomics,Public Sector Corruption&Anticorruption Measures,Poverty Monitoring&Analysis,National Governance,Governance Indicators,Pharmaceuticals&Pharmacoeconomics,Corruption&Anitcorruption Law,Public Sector Corruption&Anticorruption Measures

QED corrections to the Altarelli-Parisi splitting functions

We discuss the combined effect of QED and QCD corrections to the evolution of parton distributions. We extend the available knowledge of the Altarelli-Parisi splitting functions to one order higher in QED, and provide explicit expressions for the splitting kernels up to ${\cal O}(\alpha \, \alpha_{\mathrm{S}})$. The results presented in this article allow to perform a parton distribution function analysis reaching full NLO QCD-QED combined precision.Comment: 11 pages, 1 figure. References added, improved discussion. Final version published in EPJC. Typo corrected in Eq. (22