Surface reactivity of amphibole asbestos. A comparison between crocidolite and tremolite

Among asbestos minerals, fibrous riebeckite (crocidolite) and tremolite share the amphibole structure but largely differ in terms of their iron content and oxidation state. In asbestos toxicology, iron-generated free radicals are largely held as one of the causes of asbestos malignant effect. With the aim of clarifying i) the relationship between Fe occurrence and asbestos surface reactivity, and ii) how free-radical generation is modulated by surface modifications of the minerals, UICC crocidolite and fibrous tremolite from Maryland were leached from 1 day to 1 month in an oxidative medium buffered at pH 7.4 to induce redox alterations and surface rearrangements that may occur in body fluids. Structural and chemical modifications and free radical generation were monitored by HR-TEM/EDS and spin trapping/EPR spectroscopy, respectively. Free radical yield resulted to be dependent on few specific Fe2+ and Fe3+ surface sites rather than total Fe content. The evolution of reactivity with time highlighted that low-coordinated Fe ions primarily contribute to the overall reactivity of the fibre. Current findings contribute to explain the causes of the severe asbestosinduced oxidative stress at molecular level also for iron-poor amphiboles, and demonstrate that asbestos have a sustained surface radical activity even when highly altered by oxidative leaching

Greedy expansions with prescribed coefficients in Hilbert spaces for special classes of dictionaries

Greedy expansions with prescribed coefficients have been introduced by V. N. Temlyakov in the frame of Banach spaces. The idea is to choose a sequence of fixed (real) coefficients $\{c_n\}_{n=1}^\infty$ and a fixed set of elements (dictionary) of the Banach space; then, under suitable conditions on the coefficients and the dictionary, it is possible to expand all the elements of the Banach space in series that contain only the fixed coefficients and the elements of the dictionary. In Hilbert spaces the convergence of greedy algorithm with prescribed coefficients is characterized, in the sense that there are necessary and sufficient conditions on the coefficients in order that the algorithm is convergent for all the dictionaries. This paper is concerned with the question if such conditions can be weakened for particular dictionaries; we prove that this is the case for some classes of dictionaries related to orthonormal sequences

Labour Market Participation and Fertility in Seven European Countries: A Comparative Perspective

Although evidence suggests a correlation between fertility and employment, comparative studies on this topic are relatively scarce, particularly when considering the diverse ways in which the two variables interact in different countries. The aim of this article is to analyse the relationship between the employment and reproductive behaviours of women born between 1940 and 1979 in seven European countries (Bulgaria, Czech Republic, France, Germany, Georgia, Italy, and Lithuania). Using data from the second wave of Generation and Gender Surveys (GGS) and the Istat survey Famiglia e Soggetti Sociali (FSS) in Italy, we estimated the propensity of first and second childbirth through multi-process modelling. The article’s contribution is both theoretical and methodological. First, this research aims to investigate the correlation between employment and the timing of first and second births in a comparative perspective challenging the traditional East-West divide in Europe and the potential convergence in the impact of employment on fertility behaviours across European countries. Furthermore, the study asks whether the relationship between employment and fertility is changing similarly across European countries or whether differences tend to persist over time. The results are discussed considering women’s emancipation in different institutional settings, highlighting how women’s participation in labour markets affects reproductive behaviour. In particular, the relationship between employment and fertility behaviour is examined in relation to the opposing macro-level thesis, which suggests that the association between employment and fertility changed from negative to positive after the mid-80s. The second contribution of the article is a methodological one. It involves using simultaneous models with three equations to account for potential unobserved factors that influence the timing of the first and second childbirth and the potential endogeneity of employment status on fertility behaviour. The three equations include two log-Hazard equations for the transitions to the first and second birth order and an additional probit model to estimate the probability of being currently employed over the life course. By using this approach, we aim to provide a more comprehensive understanding of the relationship between employment and fertility, while controlling for potential confounding factors. Results suggest relevant national differences. On the one hand, the three Western countries considered in the analysis, France, Germany, and Italy, show a clear incompatibility of work and childbearing. However, in the first two, younger cohorts seem to be less affected by employment, likely because they benefitted from family policies introduced after the mid-1980s. On the other hand, the post-socialist countries are highly heterogeneous. In this area, we can find three different models. First, in Bulgaria and the Czech Republic employment is largely compatible with fertility choices resulting in a higher propensity of having the first and the second childbirth among working women. Second, in Lithuania the positive impact of employment for the first childbirth turns negative for the second one. Third, in Georgia we found a clear postponement of childbirth among working women for both birth orders. Overall, our results show deep differences across countries, suggesting that some European countries are far from demonstrating convergence in the relationship between employment and fertility