Proposal for optically realizing quantum game

We present a proposal for optically implementing the quantum game of the two-player quantum prisoner's dilemma involving nonmaximally entangled states by using beam splitters, phase shifters, cross-Kerr medium, photon detector and the single-photon representation of quantum bits.Comment: 4 pages, 4 figure

Quasispecies distribution of Eigen model

We study sharp peak landscapes (SPL) of Eigen model from a new perspective about how the quasispecies distribute in the sequence space. To analyze the distribution more carefully, we bring forth two tools. One tool is the variance of Hamming distance of the sequences at a given generation. It not only offers us a different avenue for accurately locating the error threshold and illustrates how the configuration of the distribution varies with copying fidelity $q$ in the sequence space, but also divides the copying fidelity into three distinct regimes. The other tool is the similarity network of a certain Hamming distance $d_{0}$, by which we can get a visual and in-depth result about how the sequences distribute. We find that there are several local optima around the center (global optimum) in the distribution of the sequences reproduced near the threshold. Furthermore, it is interesting that the distribution of clustering coefficient $C(k)$ follows lognormal distribution and the curve of clustering coefficient $C$ of the network versus $d_{0}$ appears as linear behavior near the threshold.Comment: 13 pages, 6 figure

Abrupt shifts in phenology and vegetation productivity under climate extremes

©2015. American Geophysical Union. All Rights Reserved. Amplification of the hydrologic cycle as a consequence of global warming is predicted to increase climate variability and the frequency and severity of droughts. Recent large-scale drought and flooding over numerous continents provide unique opportunities to understand ecosystem responses to climatic extremes. In this study, we investigated the impacts of the early 21st century extreme hydroclimatic variations in southeastern Australia on phenology and vegetation productivity using Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index and Standardized Precipitation-Evapotranspiration Index. Results revealed dramatic impacts of drought and wet extremes on vegetation dynamics, with abrupt between year changes in phenology. Drought resulted in widespread reductions or collapse in the normal patterns of seasonality such that in many cases there was no detectable phenological cycle during drought years. Across the full range of biomes examined, we found semiarid ecosystems to exhibit the largest sensitivity to hydroclimatic variations, exceeding that of arid and humid ecosystems. This result demonstrated the vulnerability of semiarid ecosystems to climatic extremes and potential loss of ecosystem resilience with future mega-drought events. A skewed distribution of hydroclimatic sensitivity with aridity is of global biogeochemical significance because it suggests that current drying trends in semiarid regions will reduce hydroclimatic sensitivity and suppress the large carbon sink that has been reported during recent wet periods (e.g., 2011 La Niña)

Genética y Deporte

Los últimos avances en el estudio del genoma humano están afectando a diversas áreas de las ciencias relacionadas con el deporte. En los últimos años se ha observado que el número de artículos aparecidos en las revistas científicas relacionados con la genética y el deporte ha sufrido un incremento exponencial. Este hecho pone de manifiesto una inquietud creciente en el mundo científico por el conocimiento y las posibilidades que la genética aplicada a distintas áreas del deporte. Paralelamente a los estudios técnicos están apareciendo voces que alertan de los posibles problemas éticos que pueden surgir de la aplicación de modificaciones genéticas en el deporte. Organismos como el Comité Olímpico Internacional, la World Anti-Doping Agency, el United States President’s Council on Bioethics y el Australian Law Reforms Comisión han estado revisando los últimos desarrollos en investigación genética y se han planteado diferentes argumentos sobre su aplicación legal en el deporte. Normalmente, las noticias que aparecen en la prensa no especializada presentan un panorama poco alentador: casi siempre se asocia la genética a nuevas formas de doping. Con el fin de conocer la realidad actual, quitando dramatismo y buscando la información más objetiva, hemos reunido a dos especialistas en medicina del deporte (Nicolás Terrados y Gil Rodas) que están inmersos en trabajos de investigación relacionados con la genética y el deporte y a un investigador en genética y biología molecular no relacionado con el mundo del deporte (Narciso Campos). Juntos hemos preparado las cinco preguntas que creemos que pueden aportar más información sobre la situación actual. Las respuestas definitivas han sido resumidas a partir de las aportaciones de cada uno de los especialistas invitados, ya que hemos observado que ha habido total coincidencia en las respuestas

Boletín MOMENTO ECONÓMICO (nueva época), año 2, núms. 21-22, Mayo-Junio 2012.

El proyecto académico del Boletín Momento Económico (nueva época) ha Alcances y 18 limitaciones de la nacionalización de los hidrocarburos en Bolivia mantenido una especial atención a las condiciones en las que se desenvuelve el modelo económico que desde hace más de tres décadas se ha impulsado en México, en escala macro, sectorial y de política económica. En artículos elaborados por miembros del GACEM y por diversos académicos invitados, se ha abierto la controversia sobre la urgente necesidad de un nuevo rumbo en el desarrollo económico y social de México. Las actuales condiciones del país han puesto de relieve que la polémica no está agotada y que, por el contrario, es indispensable profundizar en ella. En virtud de lo anterior, en este número presentamos el artículo sumario del documento "Lineamientos de política para un crecimiento sustentable y la protección social universal” (versión resumida), elaborado por Rolando Cordera Campos, Profesor Emérito de la UNAM, en el que se parte de la consideración de que México requiere construir un rumbo de desarrollo diferente. En esta nota, además de señalar las profundas dificultades del entorno global, se procede a presentar las pautas a seguir sobre el empleo y crecimiento, se propone un régimen de protección social universal; se aborda la educación, ciencia y tecnología, así como lo referente a la reforma hacendaria y financiera, el desarrollo productivo, la infraestructura y dimensión regional y la seguridad energética y protección ambiental. Lineamientos que deben configurar un nuevo curso para el desarrollo del país

Determining R-parity violating parameters from neutrino and LHC data

In supersymmetric models neutrino data can be explained by R-parity violating operators which violate lepton number by one unit. The so called bilinear model can account for the observed neutrino data and predicts at the same time several decay properties of the lightest supersymmetric particle. In this paper we discuss the expected precision to determine these parameters by combining neutrino and LHC data and discuss the most important observables. We show that one can expect a rather accurate determination of the underlying R-parity parameters assuming mSUGRA relations between the R-parity conserving ones and discuss briefly also the general MSSM as well as the expected accuracies in case of a prospective e+ e- linear collider. An important observation is that several parameters can only be determined up to relative signs or more generally relative phases.Comment: 13 pages, 13 figure

Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi

The oxidative lesion 8-oxoguanine (8-oxoG) is removed during base excision repair by the 8-oxoguanine DNA glycosylase 1 (Ogg1). This lesion can erroneously pair with adenine, and the excision of this damaged base by Ogg1 enables the insertion of a guanine and prevents DNA mutation. In this report, we identified and characterized Ogg1 from the protozoan parasite Trypanosoma cruzi (TcOgg1), the causative agent of Chagas disease. Like most living organisms, T. cruzi is susceptible to oxidative stress, hence DNA repair is essential for its survival and improvement of infection. We verified that the TcOGG1 gene encodes an 8-oxoG DNA glycosylase by complementing an Ogg1-defective Saccharomyces cerevisiae strain. Heterologous expression of TcOGG1 reestablished the mutation frequency of the yeast mutant ogg1-/- (CD138) to wild type levels. We also demonstrate that the overexpression of TcOGG1 increases T. cruzi sensitivity to hydrogen peroxide (H2O2). Analysis of DNA lesions using quantitative PCR suggests that the increased susceptibility to H2O2 of TcOGG1-overexpressor could be a consequence of uncoupled BER in abasic sites and/or strand breaks generated after TcOgg1 removes 8-oxoG, which are not rapidly repaired by the subsequent BER enzymes. This hypothesis is supported by the observation that TcOGG1-overexpressors have reduced levels of 8-oxoG both in the nucleus and in the parasite mitochondrion. The localization of TcOgg1 was examined in parasite transfected with a TcOgg1-GFP fusion, which confirmed that this enzyme is in both organelles. Taken together, our data indicate that T. cruzi has a functional Ogg1 ortholog that participates in nuclear and mitochondrial BER. © 2012 Furtado et al

The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region

We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and Confining phases merge. We find evidence of a first order transition line that ends in a second order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and critical exponents in close resemblance with simple models that show analogous critical behaviour. The measured data allow us to fit the critical exponents finding values in agreement with the mean field prediction. The location of the critical point and the slope of the first order line are accurately given.Comment: 21 text pages. 12 postscript figures available on reques