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Esca disease is an increasingly widespread grapevine syndrome that currently has no valid remedies; it causes countless symptoms and almost always leads to plant death. The aim of this work was to develop a method for the early diagnosis of the presence of the fungal complex responsible for esca disease on leaves, through the identification of fluorimetric parameters of Photosystem II (PSII) efficiency, which can signal not yet evident physiological dysfunctions.

As part of a decades-long project to safeguard the viticultural biodiversity in the wine-growing district of Pitigliano (Tuscany, Italy), the research activity carried out made it possible to rediscover two valuable autochthonous grapevine varieties, otherwise doomed to extinction: Nocchianello Bianco (whiteberried) and Nocchianello Nero (black-berried). Both the cultivars were thoroughly characterized at the genetic, phenological, and ampelographic levels, as well as the yield and grape quality were evaluated. Thanks to the results obtained, Nocchianello Bianco and Nocchianello Nero were officially reintroduced in the local and regional winemaking scenario, following the registration in the Italian Catalogue of Grapevine Varieties and the addition to the list of grapevine varieties suitable for cultivation in Tuscany.

Plant protection strategies in organic viticulture are based on the application of copper products, which is well known to generate a consistent environmental impact due to the accumulation of copper in soils and its negative effects on edaphic biodiversity. Life Green Grapes is a demonstrative project aiming to improve the sustainability of viticulture throughout the supply chain: from vine nursery to the table. In this paper, we report the main results obtained over three growing seasons (2018-2020) in response to the adoption of a strategy based on a reduced use of copper products in an organic vineyard. Plant protection treatments have been strictly planned according to forecasting models for disease development and fungicides have been partially substituted with products improving plant resistance. Green manure, known for contributing to the health of the vineyard, was also adopted. Results suggest the effectiveness of the “Green Grapes” strategy under low downy mildew pressure. Furthermore, no declines in grape quality have been observed; on the contrary, the synergic effect of green manure and substances beneficial to plants improved yield. An overall positive influence on the edaphic biodiversity was also observed.

A large-scale, fully resolved direct simulation Monte Carlo (DSMC) computation of a non-equilibrium, reactive flow of pure oxygen over a double cone is presented. Under the simulated near-continuum conditions, the computational demands are shown to be significant because of the wide range of length scales that must be resolved. Therefore, robust grid adaption capabilities and efficient parallelization of the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code that is utilized in this work are essential. The thermochemical and transport collision models were selected for efficiency and simplicity. First-principles data, obtained from the highly accurate direct molecular simulation method, were used to inform the collision models' parameters. Importantly, because SPARTA implements molecular collision models using collision-specific energies, the resulting macroscopic relaxation rates were evaluated a posteriori via zero-dimensional heat bath simulations. The comparisons of surface properties, namely heat flux and pressure, show very close agreement with previous computational fluid dynamics (CFD) results. Differences with the measurements were found to be similar to the CFD simulations. The unresolved discrepancy with the measurements could be due to inconsistent free stream conditions with the actual experimental data or missing physical phenomena altogether, for example atomic and molecular oxygen electronically excited states, three-dimensional effects, or more complex gas-surface interactions. As shown in this work, the advantages of obtaining a DSMC particle solution for these flows reside in the method's ability to be directly informed from first principles and to seamlessly describe internal energy non-equilibrium for all modes. With the advent of exascale computing and beyond, particle methods will be an increasingly important tool to verify the validity of physical assumptions in reduced-order models via fully resolved, experimental-scale simulations, down to the level of molecular-level distributions. [ABSTRACT FROM AUTHOR]

The research work carried out aimed at verifying the efficacy of Trichoderma-based products on the fertility maintenance in vineyard soils, in case of replanting. The presence of a hypofertile horizon, in fact, can cause problems in the engrafting of rooted cuttings and a slowing down in their vegetative development. The trial was carried out at the experimental farm of CREA − Research Center for Viticulture and Enology of Arezzo, during the setting up of a new Sangiovese vineyard. Rooted grafts treated with three different formulations containing some Trichoderma spp. strains were planted, considering an untreated negative control. In addition, treatments with the same formulations were repeated in the 2014-2016 three-year period, by spraying the soil, with an injector pole. Every year the shoot length and the pruning wood weight were evaluated, as well as the presence/absence of Trichoderma spp. on the root systems. Moreover, in 2016 the photosynthetic efficiency of the vines was verified. The presence of Trichoderma spp. within the rhizosphere of the vines treated was stable over time; the differences found between treated and untreated thesis were considerable, while only minor differences emerged among the plants subjected to the three different treatments. According to the results obtained, the application of Trichoderma-based products can be considered a valid practice to be used during vineyard implantation in case of difficult edaphic conditions.

The early defoliation of the fruiting area is a technique that offers considerable advantages both in relation to the quality of grapes and to pest control; on the other hand, when a very warm summer occurs, the risk of grape sunburn may increase. This paper reports the results of a pre-flowering defoliation trial carried out in the province of Arezzo (Italy) in 2017, an exceptionally hot and dry year. The results confirmed the validity of this technique in limiting yield while achieving a concurrent higher concentration of phenolic compounds without increasing the risk of burns and radiative damages of grapes.

We present two-dimensional direct molecular simulation (DMS) results for high-enthalpy nitrogen flows in thermochemical non-equilibrium around a circular cylinder. The simulations are carried out using accurate ab initio potential energy surfaces (PES) to describe N2 + N and N2 + N2 interactions. Select comparisons with the direct simulation Monte Carlo method are presented to demonstrate how the high-fidelity DMS data, both at the level of bulk flow quantities and local molecular distributions, can be used to thoroughly inform or validate simplified reduced-order descriptions. Then, a partially dissociated nitrogen flow around a circular cylinder is obtained from two successive refinements of a well-established ab initio nitrogen PES. The only input in both calculations is the respective PESs, all other simulation parameters being precisely equal. This work, enabled by large scale computing, represents the first attempt at establishing a rigorous methodology for (i) the validation of lower-fidelity, computationally efficient models using ab initio, assumption-free calculations (DMS) as benchmarks and (ii) a systematic assessment of ab initio PES accuracy using entire flow field results. [ABSTRACT FROM AUTHOR]

Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration of collision-induced dissociation of molecular species and energy transfer between the translational and internal modes of the gas molecules. Here, we describe a study of the N2 + N2 → N2 + 2N and N2 + N2 → 4N nitrogen dissociation reactions using the quasiclassical trajectory (QCT) method. The simulations used a new potential energy surface for the N4 system; the surface is an improved version of one that was presented previously. In the QCT calculations, initial conditions were determined based on a two-temperature model that approximately separates the translationalrotational temperature from the vibrational temperature of the N2 diatoms. Five values from 8000 K to 30 000 K were considered for each of the two temperatures. Over 2.4 × 109 trajectories were calculated. We present results for ensemble-averaged dissociation rate constants as functions of the translational-rotational temperature T and the vibrational temperature Tv. The rate constant depends more strongly on T when Tv is low, and it depends more strongly on Tv when T is low. Quasibound reactant states contribute significantly to the rate constants, as do exchange processes at higher temperatures. We discuss two sets of runs in detail: an equilibrium test set in which T = Tv and a nonequilibrium test set in which Tv < T. In the equilibrium test set, high-v and moderately-low-j molecules contribute most significantly to the overall dissociation rate, and this state specificity becomes stronger as the temperature decreases. Dissociating trajectories tend to result in a major loss of vibrational energy and a minor loss of rotational energy. In the nonequilibrium test set, as Tv decreases while T is fixed, higher- j molecules contribute more significantly to the dissociation rate, dissociating trajectories tend to result in a greater rotational energy loss, and the dissociation probability's dependence on v weakens. In this way, as Tv decreases, rotational energy appears to compensate for the decline in average vibrational energy in promoting dissociation. In both the equilibrium and nonequilibrium test sets, in every case, the average total internal energy loss in the dissociating trajectories is between 10.2 and 11.0 eV, slightly larger than the equilibrium potential energy change of N2 dissociation. [ABSTRACT FROM AUTHOR]