Near-infrared photoluminescence of erbium tris(8-hydroxyquinoline) spin-coated thin films induced by low coherence light sources

Copyright 2007 AIP Publishing LLC. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Applied Physics Letters [91, 021106 (2007)] and may be found at

High resolution spectroscopic analysis of seven giants in the bulge globular cluster NGC 6723

Globular clusters associated with the Galactic bulge are important tracers of stellar populations in the inner Galaxy. High resolution analysis of stars in these clusters allows us to characterize them in terms of kinematics, metallicity, and individual abundances, and to compare these fingerprints with those characterizing field populations. We present iron and element ratios for seven red giant stars in the globular cluster NGC~6723, based on high resolution spectroscopy. High resolution spectra ($R\sim48~000$) of seven K giants belonging to NGC 6723 were obtained with the FEROS spectrograph at the MPG/ESO 2.2m telescope. Photospheric parameters were derived from $\sim130$ FeI and FeII transitions. Abundance ratios were obtained from line-to-line spectrum synthesis calculations on clean selected features. An intermediate metallicity of [Fe/H]$=-0.98\pm0.08$ dex and a heliocentric radial velocity of $v_{hel}=-96.6\pm1.3~km s^{-1}$ were found for NGC 6723. Alpha-element abundances present enhancements of $[O/Fe]=0.29\pm0.18$ dex, $[Mg/Fe]=0.23\pm0.10$ dex, $[Si/Fe]=0.36\pm0.05$ dex, and $[Ca/Fe]=0.30\pm0.07$ dex. Similar overabundance is found for the iron-peak Ti with $[Ti/Fe]=0.24\pm0.09$ dex. Odd-Z elements Na and Al present abundances of $[Na/Fe]=0.00\pm0.21$ dex and $[Al/Fe]=0.31\pm0.21$ dex, respectively. Finally, the s-element Ba is also enhanced by $[Ba/Fe]=0.22\pm0.21$ dex. The enhancement levels of NGC 6723 are comparable to those of other metal-intermediate bulge globular clusters. In turn, these enhancement levels are compatible with the abundance profiles displayed by bulge field stars at that metallicity. This hints at a possible similar chemical evolution with globular clusters and the metal-poor of the bulge going through an early prompt chemical enrichment

Does national environmental regulation promote convergence in separate waste collection? Evidence from Italy

In the European Union, which is increasingly oriented towards environmentally sustainable development, separate waste collection plays a crucial role. Over the years, the EU has produced several guidelines, programmes and directives aimed to build a green society and tone down the differences between, as well as within, Member States. In Italy, the waste management system is currently regulated by Legislative Decree 152/2006, through which European directives have been incorporated into the Italian law. The existing literature has focused on the effects of L.D. 152/2006 on Separate Waste Collection (SWC) rates; however, there are not previous studies on the effects of this decree on growth rates and on convergence process among regions in terms of SWC and its items (i.e., organic, plastic, paper, and glass). This paper aims to fill these gaps. For this purpose, we implement b- and s-convergence analysis based on Generalised Method of Moments (GMM) on official Italian regional data over the period 2001e2018. Results show that Legislative Decree 152/2006 has two contrasting effects: on the one hand, it helped increase separate waste collection; on the other hand, it slowed down the convergence process in terms of separate waste collection among the Italian regions. However, the convergence process is characterised by different speeds across Italian macro-areas (Northern, Central, and Southern Italy), highlighting a three-speed country. To foster convergence, the national legislation should consider regional differences in terms of economic, infrastructural, institutional, social, and demographic characteristics

On a new theoretical framework for RR Lyrae stars I: the metallicity dependence

We present new nonlinear, time-dependent convective hydrodynamical models of RR Lyrae stars computed assuming a constant helium-to-metal enrichment ratio and a broad range in metal abundances (Z=0.0001--0.02). The stellar masses and luminosities adopted to construct the pulsation models were fixed according to detailed central He burning Horizontal Branch evolutionary models. The pulsation models cover a broad range in stellar luminosity and effective temperatures and the modal stability is investigated for both fundamental and first overtones. We predict the topology of the instability strip as a function of the metal content and new analytical relations for the edges of the instability strip in the observational plane. Moreover, a new analytical relation to constrain the pulsation mass of double pulsators as a function of the period ratio and the metal content is provided. We derive new Period-Radius-Metallicity relations for fundamental and first-overtone pulsators. They agree quite well with similar empirical and theoretical relations in the literature. From the predicted bolometric light curves, transformed into optical (UBVRI) and near-infrared (JHK) bands, we compute the intensity-averaged mean magnitudes along the entire pulsation cycle and, in turn, new and homogenous metal-dependent (RIJHK) Period-Luminosity relations. Moreover, we compute new dual and triple band optical, optical--NIR and NIR Period-Wesenheit-Metallicity relations. Interestingly, we find that the optical Period-W(V,B-V) is independent of the metal content and that the accuracy of individual distances is a balance between the adopted diagnostics and the precision of photometric and spectroscopic datasets.Comment: 51 pages, 20 figures, 9 tables, accepted for publication on Ap

Assessing the impact of tourist flows on emergency department treatment speed for residents and tourists. The case of Sorrento

Tourism is a fundamental lever of the economic and cultural development of a location. Large tourist flows can negatively impact the provision of public services, such as healthcare. This study aims to investigate emergency department (ED) treatment speed under increased demand caused by tourism. The analysis was conducted on data (covering March–October 2018) collected from the ED of a hospital in Sorrento, a renowned coastal tourist destination in Campania, Italy, by using a two-step strategy. First, we resort to the Kaplan-Meier method to compare treatment in the ED between residents and tourists. Second, through the Cox proportional hazards model, we study the impact of group-specific characteristics on the speed of treatment. The main empirical findings highlight that treatment speed is highly influenced by age and by the languages spoken by tourists. Foreign tourists are best served in off-peak periods, while in the peak arrival period, the healthcare system experiences difficulties, especially for those facing higher language barriers. What emerges is the necessity for a tourism destination to adopt measures to cope with the language heterogeneity of tourists. In a multi-cultural touristic context, healthcare providers and institutions should address the challenge of language barriers by using specialist interpreter services