A seasonal root test with Stata

Many economic time series exhibit important systematic fluctuations within the year, i.e., seasonality. Differently from usual practice, we argue that using original data should always be considered, although an unadjusted data process is more complicated than that of seasonally adjusted data. Motivations to use not-adjusted data come from the information contained in their peak and trough and from economic theory. One major complication is the unit root at seasonal frequencies. In this paper, we tackle this complication by implementing a test to identify the source of seasonality. In particular, we follow Hylleberg et al. (1993) for quarterly data. A practical example from Permanent Income Hypothesis emphasizes the utility of the command with macroeconomic time series.

The public-private pay gap: a robust quantile approach

This paper investigates whether a public sector premium exists after controlling for observable characteristics and for additional motivations, other than monetary, that may induce workers to prefer employment in the public sector. We study the entire conditional wage distribution on Italian micro data, covering the period 1998-2008. The evidence under random sampling shows the existence of a wage differential averaging at about 14% for women and 4% for men, generally lower at the high tail of the wage distribution and in the Northern regions. The premium significantly increases when possible sorting is considered; the correction is particularly large above the median of the wage distribution, therefore suggesting that the additional motivations may play an important role above all at higher wage levels. When we restrict our comparison to large private firms, a differential is confirmed for women but not for men.public employment, wage differentials, wage determination

nuclear astrophysics deep underground

Cross sections of nuclear reactions relevant for astrophysics are crucial ingredients to understand the energy generation inside stars and the synthesis of the elements. At astrophysical energies, nuclear cross sections are often too small to be measured in laboratories on the Earth surface, where the signal would be overwhelmed by the cosmic-ray induced background. LUNA is a unique Nuclear Astrophysics experiment located at Gran Sasso National Laboratories. The extremely low background achieved at LUNA allows to measure nuclear cross sections directly at the energies of astrophysical interest. Over the years, many crucial reactions involved in stellar hydrogen burning as well as Big Bang nucleosynthesis have been measured at LUNA. The present contribution provides an overview on underground Nuclear Astrophysics as well as the latest results and future perspectives of the LUNA experiment

Toxicity and residual activity of spinetoram to neonate larvae of Grapholita molesta (Busck) and Cydia pomonella (L.) (Lepidoptera: Tortricidae): Semi-field and laboratory trials

Spinetoram is a fermentation insecticide, derived from the actinomycete Saccharopolyspora spinosa. It works by disrupting the GABA-gated chloride channels and by causing persistent activation of insect nicotinic acetylcholine receptors. This study aimed to evaluate the efficacy of spinetoram for control of neonate larvae of both oriental fruit moth (OFM) Grapholita molesta (Busck) and codling moth (CM) Cydia pomonella (L.) in semi-field and laboratory trials. OFM and CM neonate larvae responded similarly to spinetoram, which showed high efficacy on both species. In semi-field experiments, regression analysis of the percentage of damaged fruits as a function of days after treatment showed a better performance of the highest spinetoram dose (10 g a.i./hl) in comparison with the maximum recommended field dose of the reference product emamectin benzoate (2.85 g a.i./hl). Surface-treated diet assays revealed LC50 values of 6.59 and 8.44 ng a.i./cm2 for neonate larvae of OFM and CM larvae, respectively. High percentages of mortality were recorded on both species after 24-h exposure to treated diet. For these reasons spinetoram could be considered a valuable tool in IPM strategies for OFM and CM control

The public sector pay gap in a selection of Euro area countries

We investigate the public-private wage differentials in ten euro area countries (Austria, Belgium, France, Germany, Greece, Ireland, Italy, Portugal, Slovenia and Spain). To account for differences in employment characteristics between the two sectors, we focus on micro data taken from EU-SILC. The results point to a conditional pay differential in favour of the public sector that is generally higher for women, at the low tail of the wage distribution, in the Education and the Public administration sectors rather than in the Health sector. Notable differences emerge across countries, with Greece, Ireland, Italy, Portugal and Spain exhibiting higher public sector premia than other countries. JEL Classification: J310, J450, O520public/private sector, Wage differentials

Baseline susceptibility of Cydia pomonella to chlorantraniliprole

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the key pest on pome fruit and walnut orchards worldwide. Its resistance to available insecticides has been widely reported. Chlorantraniliprole is an anthranilic diamide that was introduced in European countries in 2008-2009 and acts by activating the insect's ryanodine receptors. The aims of this study were to determine the baseline susceptibility of European populations of C. pomonella to chlorantraniliprole, to establish the discriminant concentrations (DC) to check the possible development of resistance, and to know the role of cytochrome P450 monooxygenases (P450) in the possible susceptibility decrease of field populations to the insecticide. Ten field populations from Spain along with others were used to calculate the baseline response of larvae to chlorantraniliprole incorporated into the diet. A pooled probit line was calculated, and three DC were established: 0.3 mg a.i./kg (close to the LC50), 1.0 mg a.i./kg (close to the LC90), and 10 mg a.i./kg diets (threefold the LC99). The DC were used to test the susceptibility of 27 field populations from France, Germany, Hungary, Italy, and Spain. The corrected mortality observed in all cases ranged within the expected interval, even with Spanish populations that showed between 12.1 and 100.0% of individuals with high P450 activity. However, the mortality caused by the DC0.3 decreased as the mean P450 activity increased. Field populations resistant to other insecticides were susceptible to chlorantraniliprole. The determined baseline codling moth susceptibility is a valuable reference for tracking possible future alterations in the efficacy of the insecticide.The authors would like to express their sincere thanks to the fruit growers and to the grower advisors of the differe nt areas (ADV technicians) who he lped identify the best orchards for the assay, to the collectors of the field populati ons in the different countries and to Mònica Pérez for her tec hnical help. Special thanks to J . L. Rison, M. O. Haxaire and S. Pasquini, from DuPont, for their helpful comments on the manuscript. This study was funded by DuPont and partially supported by grants AGL2013-49164 and AGL2016- 77373 of the Spanish Ministry for Science and Innovation and by the CERCA Programme / Generalitat de Catalunya