Potential and actual bud fruitfulness: A tool for predicting and managing the yield of table grape varieties

Microscopic bud dissection can be used to assess grapevine bud fruitfulness prior to winter pruning and long before actual bud fruitfulness can be measured in the vineyard the following spring. Bud dissections should be performed by qualified and trained personnel because inflorescence primordia are difficult to distinguish in some varieties. In the Puglia region, Southeastern Italy, in 2018 and 2019, potential fruitfulness using bud dissection and actual fruitfulness observed in the vineyard were compared for seventeen table grape varieties. The percentage of fertile buds, the number of inflorescence primordia (IP) per node, and the incidence of primary bud necrosis (PBN) were detected with bud dissection to be used either for managing winter pruning or for predicting yield during the successive season. The data were successively compared with fertile buds and actual bud fruitfulness observed in the vineyard during spring. The table grape varieties examined had similar values of fertile buds and fruitfulness both with bud dissection and in the vineyard. The application of longitudinal sections in bud dissections can be an alternative approach (or can be integrated into traditional cross sections) to distinguish IP in some difficult varieties, but the two techniques can be used together for more repeatable results. The bud dissection technique (with both cross and longitudinal sections) can provide useful insights for viticulturist to help guide winter pruning (intensity of pruning and number of canes) and to predict potential yield

Charge dynamics of a single donor coupled to a few electrons quantum dot in silicon

We study the charge transfer dynamics between a silicon quantum dot and an individual phosphorous donor using the conduction through the quantum dot as a probe for the donor ionization state. We use a silicon n-MOSFET (metal oxide field effect transistor) biased near threshold in the SET regime with two side gates to control both the device conductance and the donor charge. Temperature and magnetic field independent tunneling time is measured. We measure the statistics of the transfer of electrons observed when the ground state D0 of the donor is aligned with the SET states

Preroughening, Diffusion, and Growth of An FCC(111) Surface

Preroughening of close-packed fcc(111) surfaces, found in rare gas solids, is an interesting, but poorly characterized phase transition. We introduce a restricted solid-on-solid model, named FCSOS, which describes it. Using mostly Monte Carlo, we study both statics, including critical behavior and scattering properties, and dynamics, including surface diffusion and growth. In antiphase scattering, it is shown that preroughening will generally show up at most as a dip. Surface growth is predicted to be continuous at preroughening, where surface self-diffusion should also drop. The physical mechanism leading to preroughening on rare gas surfaces is analysed, and identified in the step-step elastic repulsion.Comment: Revtex + uuencoded figures, to appear in Physical Review Letter

Lp-cohomology of negatively curved manifolds

We compute the $L^p$-cohomology spaces of some negatively curved manifolds. We deal with two cases: manifolds with finite volume and sufficiently pinched negative curvature, and conformally compact manifolds

Effects of submerged vegetation on water clarity across climates

A positive feedback between submerged vegetation and water clarity forms the backbone of the alternative state theory in shallow lakes. The water clearing effect of aquatic vegetation may be caused by different physical, chemical, and biological mechanisms and has been studied mainly in temperate lakes. Recent work suggests differences in biotic interactions between (sub)tropical and cooler lakes might result in a less pronounced clearing effect in the (sub)tropics. To assess whether the effect of submerged vegetation changes with climate, we sampled 83 lakes over a gradient ranging from the tundra to the tropics in South America. Judged from a comparison of water clarity inside and outside vegetation beds, the vegetation appeared to have a similar positive effect on the water clarity across all climatic regions studied. However, the local clearing effect of vegetation decreased steeply with the contribution of humic substances to the underwater light attenuation. Looking at turbidity on a whole-lake scale, results were more difficult to interpret. Although lakes with abundant vegetation (>30%) were generally clear, sparsely vegetated lakes differed widely in clarity. Overall, the effect of vegetation on water clarity in our lakes appears to be smaller than that found in various Northern hemisphere studies. This might be explained by differences in fish communities and their relation to vegetation. For instance, unlike in Northern hemisphere studies, we find no clear relation between vegetation coverage and fish abundance or their diet preference. High densities of omnivorous fish and coinciding low grazing pressures on phytoplankton in the (sub)tropics may, furthermore, weaken the effect of vegetation on water clarity

Dynamic Parameters to Characterize the Thermal Behaviour of a Layer Subject to Periodic Phase Changes

Abstract The paper addresses the issue of the dynamic characterization of a layer subject to phase change (PCM) with non-sinusoidal periodic boundary conditions, which are typical of the external walls of air-conditioned building. The dynamic parameters used to characterize a monophase layer are not sufficient to describe how the temperature and heat flux trends in transfer through a layer subject to phase change are modified. Furthermore, a PCM due to the effect of latent heat associated with the phase change significantly modifies the heat storage capacity of the wall. The proposed parameters are determined by means of an explicit finite difference numerical model, considering PCM with different melting temperatures and thermophysical properties. The boundary conditions are such that one or more bi-phase interfaces originate in the layer. These parameters can be used for the thermal design of innovative walls in air-conditioned buildings with the aim of reducing power peaks entering the indoor environment, or to reduce thermal requirements, or to improve the thermal comfort within the building