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Recently new resistant and/or tolerant genotypes to the main cryptogams (downy and powdery mildew) were identified, to be used in enhancing sustainable viticulture. These cultivars (result of interspecific crossings between Vitis vinifera cultivars and other Vitis species of American and Asian origin) are experiencing a relevant expansion in Europe in viticultural regions characterized by high rainfall per year. In two sites of Trentino (Northeastern Italy) with different soil pH levels, and where these conditions are widespread, an important study was scheduled. During the period 2015-2019, fifteen resistant varieties were monitored in order to have information about agronomical and nutritional behavior. Yearly, at fruit set nutritional aspects through leaf analyses and leaf green color (SPAD indexes) were monitored. At pre-veraison, photosynthetically active biomass behavior (Normalized Difference Vegetation Index NDVI indexes) was controlled. Weather conditions of different years strongly changed the availability of nutrients in vines in relation to different genotypes and their color of vegetation and vigor. Collected results allow to suggest interventions aimed at a more suitable nutritional management for resistant varieties, in comparison of Vitis vinifera, above all for nitrogen (N), potassium (K), and zinc (Zn); in particular, for magnesium (Mg), early foliar treatments should be recommended, especially in years where rainfall is concentrated in the spring months.

The feasibility of using δ(15) N as an additional isotopic marker able to link wine to its area of origin was investigated. The whole production chain (soil-leaves-grape-wine) was considered. Moreover, the research included evaluation of the effect of the fermentation process, the use of different types of yeast and white and red vinification, the addition of nitrogen adjuvants and ultrasound lysis simulating wine ageing. The δ(15) N of grapes and wine was measured in bulk samples and compounds, specifically in proline, for the first time. Despite isotopic fractionation from soil to wine, the δ(15) N values of leaves, grapes, wine and particularly must and wine proline conserved the variability of δ(15) N in the growing soil. Fermentation and ultrasound treatment did not affect the δ(15) N values of grape must, which was therefore conserved in wine. The addition of inorganic or organic adjuvants was able to influence the δ(15) N of bulk wine, depending on the amount and the difference between the δ(15) N of must and that of the adjuvant. The δ(15) N of wine proline was not influenced by adjuvant addition and is therefore the best marker for tracing the geographical origin of wine. Copyright © 2016 John WileySons, Ltd.

We study the simplest possible model of nanocrystal consisting in a simple cubic lattice with a small number of atoms (NA ~ 10-10^3), where each atom is linked to its nearest neighbor by a quantum harmonic potential. Some properties (entropy, temperature, specific heat) of the nanocrystal are calculated numerically but exactly within the framework of the microcanonical ensemble. We find that the presence of a surface in the nanocrystal modifies the thermostatistic properties to a greater extent than the small number of atoms in the system. The specific heat Cv behaves similarly to the Einstein solid, with an asymptotic value for high temperatures that differs from that of the Dulong-Petit law by a term of the order of NA^(-1/3) and that can be explained easily in terms of the surface. The entropy is non-additive, but this is due to the presence of the surface and we show that the additivity is recovered in the thermodynamic limit. Finally, we find that, when calculations follow the canonical ensemble, results differ little for small systems (NA = 27) and are inexistent for larger systems (NA = 1000).

A method for the quantification of urea in wine, based on measuring the change in pH when urease is added to the sample, is presented and compared to the conventional dual enzyme (urease/glutamate dehydrogenase) approach. The method is linear in the range 0-30 mg·l-1 in red, white and “raisin” wines, and the detection limit (0.3 mg·l-1) is lower than for the usual enzymatic method. The differential pH technique presented here gives accurate quantification of urea in wine, being unaffected by the presence of ammonium. The amounts of urea in 195 still and sparkling commercially available wines with designation of geographic origin from the most renowned Italian grape growing areas were quantified. 17.4 % of samples were over the 3 mg·l-1 level suggested by the International Organisation of Vine and Wine for urease treatment to limit the potential risk for ethyl carbamate formation during wine ageing. Yeast strains EC1118 and SP665 can minimise urea content in wine., VITIS - Journal of Grapevine Research, Vol. 46 No. 3 (2007): Vitis