Spatio-temporal log-Gaussian Cox processes on earthquake events

This work presents an application of spatio-temporal log-Gaussian Cox processes for the description of earthquake events. To explain the overall spatial trend, spatial geological information in the study area such as faults and volcanoes are introduced in the model. Moreover, an anisotropic specification of the covariance matrix of the Gaussian process is used to improve the explanation of the phenomenon. We apply and compare different models to explain the seismic events occurred in Alaska over the last decades

Some properties of local weighted second-order statistics for spatio-temporal point processes

Diagnostics of goodness-of-fit in the theory of point processes are often considered through the transformation of data into residuals as a result of a thinning or a rescaling procedure. We alternatively consider here second-order statistics coming from weighted measures. Motivated by Adelfio and Schoenberg (2009) for the temporal and spatial cases, we consider an extension to the spatio-temporal context in addition to focussing on local characteristics. In particular, our proposed method assesses goodness-of-fit of spatio-temporal models by using local weighted secondorder statistics, computed after weighting the contribution of each observed point by the inverse of the conditional intensity function that identifies the process. Weighted second-order statistics directly apply to data without assuming homogeneity nor transforming the data into residuals, eliminating thus the sampling variability due to the use of a transforming procedure. We provide some characterisations and show a number of simulation studies

Datos imprecisos y mapas de distribución: el ejemplo de Phylan semicostatus Mulsant y Rey, 1854 (Coleoptera, Tenebrionidae) en la Serra de Tramuntana (Mallorca, Mediterráneo occidental)

Distribution maps are key tools for environmental management and biogeographic analyses. However, success in predicting spatial distribution is limited when using noisy presence/absence data sets. Both false absences and presences can be related with local departures from equilibrium (for example, temporary extinctions or unsuccessful colonisations). Moreover, false absences can arise from limited sampling effort. Here we explore an analytical strategy to get additional information on the presence/absence pattern of one target species from the presence/absence of all other species in the community. The logic is simple: the target species should display higher probability of presence at a site if a sample from this site is faunistically very close to the samples from other sites where the species occurs. Therefore, we first model presence/absence of the target species as a function of between-sample faunistic similarity. Second, the observed data for the target species are readjusted as a function of the expected probability of presence: current presences at sites with extreme low probability of presence are interpreted as unstable presences, and are recoded as absences. Seemingly, absences at sites with high probability of presence are interpreted as false absences, and are recoded as presences. In the experimental case presented herein, the recoding procedure is based on the presence/absence of 174 species, covering a broad taxonomic scope (snails, beetles, spiders and isopods). 1 km2 distribution maps of presence/absence of the endemic beetle Phylan semicostatus were modelled from these recoded data. Mapping is done using GARP based on four environmental explanatory variables. These maps seem to be more stable and less prone to fail in predicting presence than those derived directly from the observed data.Los mapas de distribución son herramientas clave para la gestión medioambiental y los análisis biogeográficos. Pero el éxito en las predicciones de distribución espacial es limitado cuando se dispone de datos imprecisos de la presencia/ausencia. Tanto falsas ausencias como falsas presencias pueden estar relacionadas con desviaciones locales del equilibrio (por ejemplo, extinciones temporales o colonizaciones no exitosas). Además, las falsas ausencias pueden surgir de un esfuerzo de muestreo limitado. Aquí se explora una estrategia analítica para obtener información adicional sobre el patron de presencia/ausencia de una especie diana a partir de la presencia/ausencia de otras especies en la comunidad. La logica es simple: la especie diana debería tener una mayor probabilidad de presencia en un punto si una muestra de este punto es faunísticamente muy similar a las muestras de otros puntos donde la especie ha sido detectada. Por tanto, primeros se modela la presencia/ausencia de la especie diana en función de la similaridad faunística entre puntos. En segundo lugar, los datos observados para la especie diana son reajustados en función de la probabilidad esperada de presencia: las presencias observadas en puntos con probabilidad de presencia muy baja son interpretadas como presencias inestables, y recodificadas como ausencias. De manera similar, las ausencias en puntos con probabilidad de presencia muy elevada son interpretadas como falsas ausencias, y recodificadas como presencias. En el caso experimental estudiado, el procedimiento de recodificación esta basado en los datos de presencia/ausencia de 174 especies, abarcando un abanico taxonómico muy amplio (caracoles terrestres, coleópteros, arañas e isópodos). El mapa de distribución de celdas de 1 km2 del coleóptero endémico Phylan semicostatus es modelado a partir de estos datos. El mapa de distribución es elaborado a partir de cuatro variables medioambientales, usando una estrategia analítica basada en algoritmos genéticos (GARP). Los mapas obtenidos con los datos recodificados parecen ser mas estables y menos susceptibles de fallar en sus predicciones que los mapas elaborados directamente con los datos originales

pi/K -> e nu branching ratios to O(e^2 p^4) in Chiral Perturbation Theory

We calculate the ratios R_{e/mu}^{(P)} = Gamma(P -> e nu)/Gamma (P -> mu nu) (P=pi,K) in Chiral Perturbation Theory to order e^2 p^4. We complement the one- and two-loop effective theory results with a matching calculation of the local counterterm, performed within the large-$N_C$ expansion. We find R_{e/mu}^{(\pi)} = (1.2352 \pm 0.0001)*10^{-4} and R_{e/mu}^{(K)} = (2.477 \pm 0.001)*10^{-5}, with uncertainty induced by the matching procedure and chiral power counting. Given the sensitivity of upcoming new measurements, our results provide a clean baseline to detect or constrain effects from weak-scale new physics in these rare decays. As a by-product, we also update the theoretical analysis of the individual pi/K -> \ell nu modes.Comment: 40 pages, 4 figures, 3 table

Analysis of ORF5 and Full-Length Genome Sequences of Porcine Reproductive and Respiratory Syndrome Virus Isolates of Genotypes 1 and 2 Retrieved Worldwide Provides Evidence that Recombination Is a Common Phenomenon and May Produce Mosaic Isolates

Recombination is currently recognized as a factor for high genetic diversity, but the frequency of such recombination events and the genome segments involved are not well known. In the present study, we initially focused on the detection of recombinant porcine reproductive and respiratory syndrome virus (PRRSV) isolates by examining previously published data sets of ORF5 sequences (genotypes 1 and 2) obtained worldwide. We then examined full-length genome sequences in order to determine potential recombination breakpoints along the viral genome. For ORF5, 11 sets of genotype 1 sequences from different geographical areas, including 2 Asian, 1 American, and 7 European regions, and three sets of genotype 2, including sets from China, Mexico, and the United States, were analyzed separately. Potential recombination breakpoints were detected in 10/11 genotype 1 sets, including 9 cases in which the clustering of at least one isolate was different before and after the breakpoints. In genotype 2, potential breakpoints and different tree clustering of at least one strain before and after the breakpoint were observed in 2 out of 3 sets. The results indicated that most of the ORF5 data sets contained at least one recombinant sequence. When the full-length genome sequences were examined, both genotype 1 and 2 sets presented breakpoints (10 and 9, respectively), resulting in significantly different topologies before and after the breakpoints. Mosaic genomes were detected in genotype 1 sequences. These results may have significant implications for the understanding of the molecular epidemiology of PRRSV. IMPORTANCE PRRSV is one of the most important viruses affecting swine production worldwide, causing big economic losses and sanitary problems. One of the key questions on PRRSV arises from its genetic diversity, which is thought to have a direct impact on immunobiology, epidemiology, diagnosis, and vaccine efficacy. One of the causes of this genetic diversity is recombination among strains. This study provides evidence that recombinant PRRSV isolates are common in most of the countries with significant swine production, especially PRRSV genotype 1. This observation has implications in the proper characterization of PRRSV strains, in the future development of phylogenetic studies, and in the development of new PRRSV control strategies. Moreover, the present paper emphasizes the need for a deeper understanding of the mechanisms and circumstances involved in the generation of genetic diversity of PRRSV