Leaf trapping and retention of particles by holm oak and other common tree species in Mediterranean urban environments

Holm oak (Quercus ilex), a widespread urban street tree in the Mediterranean region, is widely used as biomonitor of persistent atmospheric pollutants, especially particulate-bound metals. By using lab- and field-based experimental approaches, we compared the leaf-level capacity for particles’ capture and retention between Q. ilex and other common Mediterranean urban trees: Quercus cerris, Platanus × hispanica, Tilia cordata and Olea europaea. All applied methods were effective in quantifying particulate capture and retention, although not univocal in ranking species performances. Distinctive morphological features of leaves led to differences in species’ ability to trap and retain particles of different size classes and to accumulate metals after exposure to traffic in an urban street. Overall, P. × hispanica and T. cordata showed the largest capture potential per unit leaf area for most model particles (Na+ and powder particles), and street-level Cu and Pb, while Q. ilex acted intermediately. After wash-off experiments, P. × hispanica leaves had the greatest retention capacity among the tested species and O. europaea the lowest. We concluded that the Platanus planting could be considered in Mediterranean urban environments due to its efficiency in accumulating and retaining airborne particulates; however, with atmospheric pollution being typically higher in winter, the evergreen Q. ilex represents a better year-round choice to mitigate the impact of airborne particulate pollutants.

Vox Populi, Vox Dei? A closer look at the ‘public opinion’ argument for retention

The Japanese government’s justification for retaining the death penalty is that abolition would erode the legitimacy of and public trust in the criminal justice system, leading to victims’ families taking justice into their own hands. This justification is based on the results of a regularly administered public opinion survey, which is said to show strong public support for the death penalty. However, a close analysis of the results of the 2014 survey fails to validate this claim. Just over a third of respondents were committed to retaining the death penalty at all costs, while the rest accepted the possibility of future abolition, with some of them seeing this as contingent on the introduction of life imprisonment without parole as an alternative sentence. These findings hardly describe a society that expects the strict application of the death penalty and whose trust in justice depends on the government’s commitment to retaining it. My reading of the 2014 survey is that the Japanese public is ready to embrace abolition. Japan, after all, is a signatory to the International Covenant on Civil and Political Rights, which calls on states not to delay or prevent abolition, so this should be welcome news for the Japanese government!

Customer retention management in the recession

The purpose of this article is to explore customer retention strategies and tactics implemented by firms in recession. Our investigations show just how big a challenge many organizations face in their ability to manage customer retention effectively. While leading organizations have embedded real-time customer life cycle management, developed accurate early warning systems, price elasticity models and ‘deal calculators’, the organizations we spoke to have only gone as far as calculating the value at risk and building simple predictive models.