One-loop conformal invariance of the type II pure spinor superstring in a curved background

We compute the one-loop beta functions for the Type II superstring using the pure spinor formalism in a generic supergravity background. It is known that the classical pure spinor BRST symmetry puts the background fields on-shell. In this paper we show that the one-loop beta functions vanish as a consequence of the classical BRST symmetry of the action. © SISSA 2007.

La coyuntura económica de América Latina: ¿se justifica el optimismo?

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Comentario a la presentación de José Antonio Ocampo: Los paradigmas del desarrollo en la historia latinoamericana"

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Comentario a la presentação do José Antonio Ocampo: Os paradigmas do desenvolvimento na história latino-americana"

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América Latina en el 2007: situación económica y del mercado de trabajo

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Hacia un desarrollo inclusivo: el caso de Chile

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Una nueva estrategia para Chile en el siglo XXI

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Hacia un crecimiento inclusivo

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Política tributaria, espacio fiscal y equidad

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Positive selection results in frequent reversible amino acid replacements in the G protein gene of human respiratory syncytial virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a flipflop phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.

Eficiencia y equidad en el sistema de salud chileno

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Subdesarrollo latinoamericano y la teoría del desarrollo

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Cinqüenta anos de pensamento na CEPAL

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A inflação chilena: um enfoque heterodoxo

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