The kernel method to compute the intensity of segregation for reactive pollutants: Mathematical formulation

It is well known that turbulent dispersion influences chemical reactions and that computation of reactant concentrations or mean chemical reaction rates can suffer of serious error when small-scale atmospheric processes' effects on chemical transformation are neglected. A quantity that gives a measure of the influence of turbulent dispersion on second-order chemical reaction rates is the intensity of segregation. A nonparametric estimator based on the kernel method aimed at measuring the intensity of segregation is proposed. Numerical benchmark tests, in the case of a Gaussian plume, are performed to study the suitability of this technique. The estimator works well, especially for small and moderate separation from the plume centreline and generally in the smooth parts of the estimated function. The effective reaction rate is computed and the percentage error emerges to be less than 5% in the best estimation intervals, and less than 40% in the worst. A method to reduce percentage error is introduced and improved performances are observed. The estimator proposed turns out to be particularly suitable for Lagrangian air quality modelling because it permits conservation of the grid independence.     

Testing kernel density reconstruction for Lagrangian photochemical modelling

In recent years, a number of pioneering works have shown as Lagrangian models can be of great interest when dealing with photochemistry, provided that special care is given in the reconstruction of chemicals concentration in the atmosphere. Density reconstruction can be performed through the so-called “box counting” method: an Eulerian grid for chemistry is introduced and density is computed counting particles in each box. In this way one of the main advantages of the Lagrangian approach, the grid independence, is lost. In this paper, a new approach to Lagrangian photochemical modelling is investigated and the chemical module of the Photochemical Lagrangian Particle Model (PLPM) is described and fully tested for stability, reliability and computational weight. Photochemical reactions are treated in PLPM by means of the complex chemical mechanism SAPRC90 and four density reconstruction methods have been developed, based on the kernel density estimator approach, in order to obtain grid-free accurate concentrations.     

Prenatal diagnosis of recurrence of cystic hygroma with normal chromosomes

Cyst-like masses in the neck and back region, simulating an encephalocele, were detected by midtrimester ultrasound examinations in two sib fetuses. After termination, the fetuses were found to have large cystic hygromas. The present observation strongly suggests the existence of an autosomal recessive type of cystic hygroma.     

A European supergrid for renewable energy: local impacts and far-reaching challenges

This article assesses the impact of extensive deployment of indigenous and external renewable energy sources on a local electricity system (Sardinia Island) and discusses the main challenges faced by the European power grids in integrating high shares of renewable-based generation technologies. It presents the 2030 scenarios for the Sardinian power system and the results of steady-state analyses in extreme (renewable) generation and consumption conditions. These results are eventually combined with the assessment of key technology development trends to explain how this can affect the development of a European supergrid. In general, the article stresses that rendering the bulk-power system capable of accommodating high renewable energy penetration not only requires reinforcing the electricity highways but also demands carefully planning the architecture of and the interface with regional power systems.     

L'Aquila's reconstruction challenges: has Italy learned from its previous earthquake disasters?

Italy is an earthquake‐prone country and its disaster emergency response experiences over the past few decades have varied greatly, with some being much more successful than others. Overall, however, its reconstruction efforts have been criticised for being ad hoc, delayed, ineffective, and untargeted. In addition, while the emergency relief response to the L'Aquila earthquake of 6 April 2009—the primary case study in this evaluation—seems to have been successful, the reconstruction initiative got off to a very problematic start. To explore the root causes of this phenomenon, the paper argues that, owing to the way in which Italian Prime Minister Silvio Berlusconi has politicised the process, the L'Aquila reconstruction endeavour is likely to suffer problems with local ownership, national/regional/municipal coordination, and corruption. It concludes with a set of recommendations aimed at addressing the pitfalls that may confront the L'Aquila reconstruction process over the next few years.