Near observational equivalence and fractionally integrated processes

The aim of this paper is to study the presence of nearly observationally equivalence problems in fractionally integrated processes. In order to illustrate our results, by means of a Monte Carlo study, we analyse the finite sample behaviour of the usual Durbin-Watson statistic in a regression between two independent nonstationary fractionally integrated processes wiht MA(l) innovations

Monte Carlo evidence on the power of the Durbin-Watson test against nonsense relationships

It is a well-known fact that, in linear regressions involving the levels of integeated processes spuriously related, the Durbin-Watson statistic converges in probability to zero. This, in turn, implies that this statistic can provide an useful testing procedure against the presence of nonsense relationships. Marmol (1997) extends this result to the case of spurious regressions among nonstationary fractionally integrated processes. The aim of this paper is to provide a theoretical overview of these asymptotic results as well as Monte Carlo evidence on the behavior of the Durbin-Watson test in small samples

El consumo de cocaína: Algunas lecciones de España

In this paper, we examine the socioeconomic factors that determine cocaine consumption in adults aged over 18 years in Spain. For data from household alcohol and drug surveys for the period 2007-2012 (EDADES 2007, 2009, 2011), we used, first, a decision tree to identify the main predictors of cocaine use and high-risk profiles of cocaine consumers and, next, a multinomial logistic regression model to explain cocaine consumption in terms of sex, age, marital status, employment status, education level, income, household size and perceived health status. The results indicate that the main predictors of cocaine use are marital status, sex, employment status, age, education level and household size. The main cocaine user propensity profile is a young single man with a low level of education and unemployed, who should, therefore, be the main target of campaigns for preventing illicit drug use.Este trabajo analiza los factores socioeconómicos que determinan el consumo de cocaína en adultos españoles de más de 18 años. Con los datos de las encuestas domiciliarias de alcohol y drogas para el período 2007-2012 (EDADES 2007, 2009, 2011), planteamos un modelo de árboles de decisión para identificar los principales predictores del consumo de cocaína, así como los grupos de perfiles con mayor riesgo de consumo. Al mismo tiempo, construimos un modelo de regresión logística multinomial para explicar el consumo de cocaína y sus diferentes grados de una persona adulta en función del sexo, la edad, el estado civil, la situación laboral, el nivel educativo, los ingresos, el tamaño del hogar en el que vive y la percepción que tiene de su estado de salud. Los resultados muestran que los principales predictores del consumo de cocaína en adultos en España son el estado civil, el sexo, la situación laboral, la edad, el nivel educativo y el tamaño del hogar. El perfil de adultos con mayor propensión al consumo de cocaína es el de varones jóvenes con un bajo nivel de educación, que viven solos y están desempleados. Esta debería ser, pues, la población en la que centrar las campañas de prevención del consumo de drogas ilícita

Market-based metrics for the systemic risk in climate transition

The transition to a low-carbon economy carries potential ramifications for financial stability. If unanticipated, changes in climate policy and regulation, technology, and consumer and investor preferences can cause sudden market price readjustments. Javier Ojea Ferreiro, Juan C. Reboredo, and Andrea Ugolini have developed an empirical setup to assess various sets of scenarios. They write that an early warning indicator is essential to help identify the exposure of financial institutions to different transition paths

Economic crisis and the unemployment effect on household food expenditure: The case of Spain

This paper examines the unemployment effect on food expenditure (UEFE) for Spanish households and quantifies its magnitude in boom and crisis periods. The results show that the UEFE was negative in both contexts but was reinforced during the economic crisis. Applying propensity score matching and difference-in-differences techniques to a sample of Spanish households for 2006 and 2013 (representative of a boom period and a crisis period, respectively), we found that the UEFE amounted to 2.9% in the boom period and to 4.5% in the crisis period. Quantile difference-in-differences estimates confirmed that the economic crisis enhanced the UEFE for Spanish households, with this effect decreasing continuously up to quantile 0.9. The UEFE was exacerbated mainly in those economically disadvantaged households

Oral administration of zein-based nanoparticles reduces glycemia and improves glucose tolerance in rats

The aim was to evaluate the effect of zein-based nanoparticles on the glucose homeostasis, following oral administration to Wistar rats. For this purpose, bare nanoparticles (NP, with tropism for the upper intestinal regions) and poly(ethylene glycol)-coated nanoparticles (NP-PEG), with the capability to reach the ileum and cecum of animals, were evaluated. Both formulations were spherical in shape, displaying sizes around 200 nm and a negative surface zeta potential. The oral administration of a single dose of these nanoparticles to animals (50 mg/kg) induced a significant decrease of the glycemia, compared control rats and in animals treated with the free protein (p < 0.001). Moreover, these nanoparticles improved the glycemic control against an intraperitoneal glucose tolerance test; particularly NP-PEG. These findings would be due to an increased release of glucagon-like peptide-1 (GLP-1) by L-cells, which are more abundant in distal regions of the intestine. In fact, the GLP-1 blood levels of animals treated with nanoparticles were significantly higher than controls (about 40 % and 60 % for NP and NP-PEG groups, respectively). This higher capability of NP-PEG, with respect to NP, to increase the release of GLP-1 and control glycemia would be related to its ability to reach the distal areas of the small intestine