85 research outputs found
On the additional boundary condition of wind-driven ocean models on the eastern coast
In the homogeneous model of the wind-driven ocean circulation, the dynamics of the basin interior is basically governed by the Sverdrup balance and the related no mass-flux condition on the eastern boundary of the basin, which we assume to be square for conceptual simplicity. In the presence of lateral diffusion of relative
vorticity, the additional condition on the eastern boundary (like the conditions on the other boundaries) is not demanded on physical grounds but it is arbitrary to a large extent. Hence, certain choices of such boundary condition can produce overall solutions which are “far” from that of Sverdrup in the eastern part of the domain, without any physical reason. In the present note we show that this discrepancy can be strongly reduced if the adopted additional boundary condition has the same form as that implicitly satisfied by the Sverdrup solution. Unlike the common approach, a criterion is thus derived which selects a suitable partial slip boundary condition according to the specific wind-stress field which is taken into account
Influence of vineyard inter-row management and clone on 'Sauvignon Blanc' performance in Friuli Venezia Giulia (north-eastern Italy)
The vineyard inter-row management affects grapevine vegetative and bunch health status, as well as yield and grape quality parameters. Several studies assessed that cover-cropped inter-row in place of soil tillage often reduced plant vigour and yield but positively contributed to vineyard ecosystem services and, to a lower extent, to grape quality. In 2013 and 2014, two inter-row management strategies, i.e. soil tillage and mowing of spontaneous cover crops, were compared in an organic vineyard in north-eastern Italy and cultivated with 'Sauvignon Blanc' (Vitis vinifera L.), clones R3 and 297. In particular, the effects of tillage and mowing treatments on grapevine vegetative and bunch health status, yield and grape quality were evaluated. The vegetative parameters were lower in the mowing treatment than in the tillage one and in clone R3 compared to 297. The incidence of Botrytis cinerea was higher in the tillage treatment than in the mowing one and in clone 297 compared to R3. A significant reduction of the yield and bunch weight was ascertained in the mowing treatment, and these parameters were higher for clone 297 compared to clone R3. Titratable acidity was significantly higher in the tillage treatment than in the mowing one and in clone 297 compared to R3. Moreover, hue of berry skin was qualitatively better in the tillage treatment than in the mowing one. In the pedo-climatic conditions of Friuli Venezia Giulia (north-eastern Italy), the management of the vineyard inter-row with spontaneous cover crops proved to be effective to manage grapevine vigour, reducing yield and improving quality of the grapes during maturation
Statistical mechanics of the mixed majority-minority game with random external information
We study the asymptotic macroscopic properties of the mixed majority-minority
game, modeling a population in which two types of heterogeneous adaptive
agents, namely ``fundamentalists'' driven by differentiation and
``trend-followers'' driven by imitation, interact. The presence of a fraction f
of trend-followers is shown to induce (a) a significant loss of informational
efficiency with respect to a pure minority game (in particular, an efficient,
unpredictable phase exists only for f<1/2), and (b) a catastrophic increase of
global fluctuations for f>1/2. We solve the model by means of an approximate
static (replica) theory and by a direct dynamical (generating functional)
technique. The two approaches coincide and match numerical results
convincingly.Comment: 19 pages, 3 figure
Structure-preserving desynchronization of minority games
Perfect synchronicity in -player games is a useful theoretical dream, but
communication delays are inevitable and may result in asynchronous
interactions. Some systems such as financial markets are asynchronous by
design, and yet most theoretical models assume perfectly synchronized actions.
We propose a general method to transform standard models of adaptive agents
into asynchronous systems while preserving their global structure under some
conditions. Using the Minority Game as an example, we find that the phase and
fluctuations structure of the standard game subsists even in maximally
asynchronous deterministic case, but that it disappears if too much
stochasticity is added to the temporal structure of interaction. Allowing for
heterogeneous communication speeds and activity patterns gives rise to a new
information ecology that we study in details.Comment: 6 pages, 7 figures. New version removed a section and found a new
phase transitio
Impact of Leaf Removal, Applied Before and After Flowering, on Anthocyanin, Tannin, and Methoxypyrazine Concentrations in ‘Merlot’ (Vitis viniferaL.) Grapes and Wines
7siThe development and accumulation of secondary metabolites in grapes determine wine color, taste, and aroma. This study aimed to investigate the effect of leaf removal before flowering, a practice recently introduced to reduce cluster compactness and Botrytis rot, on anthocyanin, tannin, and methoxypyrazine concentrations in Merlot' grapes and wines. Leaf removal before flowering was compared with leaf removal after flowering and an untreated control. No effects on tannin and anthocyanin concentrations in grapes were observed. Both treatments reduced levels of 3-isobutyl-2-methoxypyrazine (IBMP) in the grapes and the derived wines, although the after-flowering treatment did so to a greater degree in the fruit specifically. Leaf removal before flowering can be used to reduce cluster compactness, Botrytis rot, and grape and wine IBMP concentration and to improve wine color intensity but at the expense of cluster weight and vine yield. Leaf removal after flowering accomplishes essentially the same results without loss of yield. © 2016 American Chemical Society.reservedmixedSivilotti, Paolo; Herrera, Jose Carlos; Lisjak, Klemen; Baša Česnik, Helena; Sabbatini, Paolo; Peterlunger, Enrico; Castellarin, Simone DiegoSivilotti, Paolo; Herrera, Jose Carlos; Lisjak, Klemen; Baša Česnik, Helena; Sabbatini, Paolo; Peterlunger, Enrico; Castellarin, Simone Dieg
Overview of the FTU results
Since the 2018 IAEA FEC Conference, FTU operations have been devoted to several experiments covering a large range of topics, from the investigation of the behaviour of a liquid tin limiter to the runaway electrons mitigation and control and to the stabilization of tearing modes by electron cyclotron heating and by pellet injection. Other experiments have involved the spectroscopy of heavy metal ions, the electron density peaking in helium doped plasmas, the electron cyclotron assisted start-up and the electron temperature measurements in high temperature plasmas. The effectiveness of the laser induced breakdown spectroscopy system has been demonstrated and the new capabilities of the runaway electron imaging spectrometry system for in-flight runaways studies have been explored. Finally, a high resolution saddle coil array for MHD analysis and UV and SXR diamond detectors have been successfully tested on different plasma scenarios
- …