La mejora de las predicciones con la inclusión de una variable agregada: aplicación a las tasas de variación del PIB de una muestra de economías europeas

El presente trabajo ilustra empíricamente cómo se pueden mejorar las predicciones de las tasas de variación, TV, del output real, PIB, de una muestra de países europeos. Esta mejora ha sido posible gracias al acceso a una base de datos de la Universidad de Groningen, que nos ha permitido calcular las tasas de variación del total de output de los países considerados. Cuando incluimos la tasa de variación total en los modelos AR(3), modelo autorregresivo con tres retardos de la tasa de variación del output de cada país, hemos observado una mejora substancial en las predicciones anuales de de las tasas de variación del output real de cada país.The present work empirically illustrates how the forecast of the annual output growth rates (GR) (where the output is the real gross domestic product (GDP)), from a sample of European countries could be improved. This improvement has been possible by means of using a database that has let us to calculate the aggregated GR of the GDP of the countries sample. When we include the common GR in the AR(3) model of each country’s data, we have observed a substantially improving of one-step-ahead forecasts of GR, due to this common variabl

A generalization of Jeffreys' rule for non regular models

We propose a generalization of the one-dimensional Jeffreys’ rule in order to obtain non informative prior distributions for non regular mod- els, taking into account the comments made by Jeffreys in his arti- cle of 1946. These non informatives are parameterization invariant and the Bayesian intervals have good behavior in frequentist inference. In some important cases, we can generate non informative distributions for multi-parameter models with non regular parameters. In non regular models, the Bayesian method offers a satisfactory solution to the infer- ence problem and also avoids the problem that the maximum likelihood estimator has with these models. Finally, we obtain non informative dis- tributions in job-search and deterministic frontier production homoge- nous model

Midiendo la variabilidad en caracteres cualitativos

The study of variability in categorical characteristics is rarely discussed. From a less used viewpoint of variability in quantitative variables, as it is the one of dissimilarity, which is different from the dispersion that, for example, the variance provides, we propose the construction of two coefficients that measure the variability in qualitative or categorical variables, which we call coefficients of dissimilarity. Simple examples are provided to introduce the measures, so that the teacher can also evaluate the idea students have about variability, dispersion and dissimilarityEl estudio de la variabilidad en caracteres categóricos rara vez es abordado. A partir de un enfoque menos usado de la variabilidad en variables cuantitativas, el de la disparidad, distinto al de la dispersión que, por ejemplo, proporciona la varianza, se propone la construcción de dos coeficientes de medida de la variabilidad en variables cualitativas o categóricas a los que llamamos coeficientes de disparidad. La sencillez y proximidad de los mismos permiten que sean abordados en un curso introductorio de estadística descriptiva. Ejemplos sencillos son ofrecidos para introducir las medidas y para, también, que el profesor constate la idea que el alumno tiene sobre variabilidad, dispersión y disparidad

Horn fragments of the Halpern-Shoham Interval Temporal Logic

We investigate the satisfiability problem for Horn fragments of the Halpern-Shoham interval temporal logic depending on the type (box or diamond) of the interval modal operators, the type of the underlying linear order (discrete or dense), and the type of semantics for the interval relations (reflexive or irreflexive). For example, we show that satisfiability of Horn formulas with diamonds is undecidable for any type of linear orders and semantics. On the contrary, satisfiability of Horn formulas with boxes is tractable over both discrete and dense orders under the reflexive semantics and over dense orders under the irreflexive semantics but becomes undecidable over discrete orders under the irreflexive semantics. Satisfiability of binary Horn formulas with both boxes and diamonds is always undecidable under the irreflexive semantics

Contrasting patterns of genetic and phenotypic differentiation in two invasive salmonids in the southern hemisphere

Peer reviewe

El concepto de desigualdad en Vilfredo Pareto (1848-1923)

Recoge las ponencias presentadas en el V Congreso Internacional de Historia de la Estadística y de la Probabilidad, celebrado en Santiago de Compostela los días 17 y 18 de septiembre de 200

Prevalence and distribution of intestinal parasites in stray dogs in the northwest area of Mexico

Zoonotic parasitic infections are a major global public and veterinary health problem and widespread among stray dogs. The objective of this study was to establish the prevalence of intestinal parasites in stray dogs in the urban, rural and coastal areas of Mexicali County in northwest Mexico. In 2014, from January to December, 380 stray dogs were captured. The entire small intestine, cecum and faeces samples were collected and examined by using simple zinc sulfate flotation and Lugol’s solution staining. Data were statistically analysed. Overall, about 21.5% of examined dogs were found positive for intestinal parasites. Toxocara canis was the most frequent detected parasite, with a prevalence of 7.1%, followed by Toxascaris leonina (5.5%), Cystoisospora spp. (5.0%), Taenia spp. (3.9%) and Dipylidium caninum (2.8%). Dogs were more frequently found to be infected with a single genus of intestinal parasite (18.7%) than co-infected (2.8%). Intestinal parasites were more prevalent in samples from the coastal area (25%) than in those from the rural (24.4%) and urban (20.6%) areas, however, only statistical association was found between capture area and specific intestinal parasitic infection. There were significant differences in the prevalence of taeniasis among two age groups (P<0.01). A seasonal peak of prevalence for intestinal parasitic infections was found during spring (P<0.05), corresponding with a seasonal peak of prevalence of T. canis (P<0.05). The wide range of isolated parasites indicated that people residing in this area are at risk of exposure to these potentially hazardous zoonotic pathogens

Laser based series interconnection of chalcopyrite und perovskite solar cells Analysis of material modifications and implications for achieving small dead area widths

Both nanosecond pulses and picosecond laser pulses are used for P2 patterning of chalcopyrite Cu In,Ga Se2, CIGSe and metal halide perovskite solar cell absorber layers. For CIGSe, the range of the modified material visualized by photoluminescence imaging is significantly wider than the actual physical linewidth, since energy input by the laser pulses leads to material modification in the vicinity of the scribed lines. This effect does not occur with the perovskite absorber layers, where there is no apparent influence on the edge regions. From numerical calculations of the temperature depth profiles and the surface temperature distributions it is concluded that this effect is due to the significantly lower perovskite absorber layer thickness compared to CIGSe and the nevertheless significantly higher laser fluence required for perovskite ablation. The unaffected edge regions around the P2 line in the perovskite enabled a reduction of the dead area width in the fabrication of 3 segmented mini modules, which could be significantly reduced from 430 to 230 m, while increasing the aperture area power conversion efficiency and also the geometric fill factor, which could be increased up to 94.