On the Role of NAO Driven Interannual Variability in Rainfall Seasonality on Water Resources and Hydrologic Design in a Typical Mediterranean Basin

In the last several decades, extended dry periods have affected the Mediterranean area with dramatic impacts on water resources. Climate models are predicting further warming, with negative effects on water availability. The authors analyze the hydroclimatic tendencies of a typical Mediterranean basin, the Flumendosa basin located in Sardinia, an island in the center of the Mediterranean Sea, where in the last 30 years a sequence of dry periods has seriously impacted the water management system. Interestingly, in the historic record the annual runoff reductions have been more pronounced than the annual precipitation reductions. This paper performs an analysis that links this runoff decrease to changes in the total annual precipitation and its seasonal structure. The seasonality is a key determinant of the surface runoff process, as it reflects the degree to which rainfall is concentrated during the winter. The observed reductions in winter precipitation are shown here to be well correlated (Pearson correlation coefficient of −0.5) with the North Atlantic Oscillation (NAO) index. Considering the predictability of the winter NAO, there is by extension an opportunity to predict future winter precipitation and runoff tendencies. The recent hydroclimatic trends are shown to impact hydrologic design criteria for water resources planning. The authors demonstrate that there is a dangerous increase of the drought severity viewed from the perspective of water resources planning

Use of potassium polyaspartate for the tartaric stabilization of Sicilian white wines

Cold stabilization is a common method used to avoid tartaric acid crystals from forming in bottled wine, but this technique shows some inconveniences on the sensory characteristics and energy cost. In the present research, the tartaric stabilization in Sicilian white wines, with a recently permissible molecule in oenology, was studied: the potassium polyaspartate (PAK). The PAK has a negative charge at wine pH and allows to sequester the K+ cations; consequently it inhibits the formation and the growth of potassium bitartrate crystals. PAK is a relatively small polymer; perfectly microfiltrated and does not allow the filling phenomena in filtration membranes. The adding of PAK allowed to reduce almost all the tartaric precipitations on very unstable wines, regardless of the chemical-physical characteristics of the treated white wines. The stability of PAK, after thermal stress of the wine added to this polymer, was confirmed evaluating different analytical parameters such as pH, total acidity and buffer power, while variations in the conductivity of wines seemed to indicate a residual tartaric instability. In conclusion, the use of PAK makes possible to improve the sensory characteristics of wines, considering lower losses of tartaric acid and potassium, which are important for acid perception and acid persistence (buffer power), as well as reducing production costs and low environmental impact

Calibration of a 400 mm helical master gear at INRIM

A complete - and first ever at INRIM - calibration of a master gear is described. This includes the evaluation of the uncertainty of measurement, which is particularly challenging for this type of complex calibration

Drying kinetics and physico-chemical quality of mango slices

Mango (Mangifera indica L.) is an important tropical fruit consumed worldwide and grown in Italy only in Sicily, where the areas of the Tyrrhenian coast have proved to be suitable to produce valuable fruits. Mango fruit has a pleasant aroma and taste, which are important qualities for consumer’s sensorial acceptance. However, they are highly perishable, prone to progressive undesired changes if stored untreated, resulting in around 25% postharvest losses, which is further increased during storage and transportation. An alternative for reducing the above-mentioned undesired changes is the dehydration of the cut fruit, which reduce the fruit water activity, thereby avoiding the deteriorative process and extending the shelf-life. This study investigates the effect of dehydration at different temperatures (50, 60 and 70°C) on drying kinetics and volatile compounds of two cultivars (Keitt and Osteen) of mango fruits cultivated in Sicily. Significant losses of volatile constituents of fresh mango occurred at higher temperature, especially for the Osteen cultivar. A diffusion model including the effect of shrinkage is also proposed, which may be used to describe drying behaviour of fruits and to define the optimal drying conditions.. Experimental data of the moisture ratio during drying were well predicted by the model

Self-organization, scaling and collapse in a coupled automaton model of foragers and vegetation resources with seed dispersal

We introduce a model of traveling agents ({\it e.g.} frugivorous animals) who feed on randomly located vegetation patches and disperse their seeds, thus modifying the spatial distribution of resources in the long term. It is assumed that the survival probability of a seed increases with the distance to the parent patch and decreases with the size of the colonized patch. In turn, the foraging agents use a deterministic strategy with memory, that makes them visit the largest possible patches accessible within minimal travelling distances. The combination of these interactions produce complex spatio-temporal patterns. If the patches have a small initial size, the vegetation total mass (biomass) increases with time and reaches a maximum corresponding to a self-organized critical state with power-law distributed patch sizes and L\'evy-like movement patterns for the foragers. However, this state collapses as the biomass sharply decreases to reach a noisy stationary regime characterized by corrections to scaling. In systems with low plant competition, the efficiency of the foraging rules leads to the formation of heterogeneous vegetation patterns with $1/f^{\alpha}$ frequency spectra, and contributes, rather counter-intuitively, to lower the biomass levels.Comment: 11 pages, 5 figure