Search results for "Oak"

Downy oak woods of Italy: phytogeographical remarks on a controversial taxonomic and ecological issue

2011

The importance of downy oak as an integral component of the "submediterranean" woods has been underscored in many studies. Nevertheless, terms like "submediterranean" and "downy oak" are some of the most faintly understood concepts in the European phytogeographical and taxonomical research. Downy oak is well known to be a problematic taxon: the name "Quercus pubescens" (= Q. humilis) piles together populations characterized by an increasing phenotypic and genomic polymorphism along north-south gradients, which is commonly explained as the result of a "founder effect" given by a relatively fast post-glacial re-colonization of the northern stands through rare long-distance dispersal events. O…

Recovery of cork forests and enhancement of by-products

2022

Cork oak (Quercus suber L.) is a tree species native to the western Mediterranean Basin (EUFORGEN 2019). Cork oak forests are human-shaped ecosystems that have to be managed to be preserved in a long-term perspective. Cork oak stands range from closed forests to open woodlands, provide high ecosystem services, mainly through cork production, support high biodiversity and provide carbon storage and water regulation services. Due to their important ecological role, these ecosystems are listed in the European Habitats Directive (Habitat 9330: Quercus suber forests, EEC, 1992). In the last years, especially in Italy, cork oak stands are undergoing a relevant regression due to the decline of tra…

Cloaking by anomalous localized resonance via spectral analysis of a Neumann-Poincaré operator

2014

The classical notion of Neumann-Poincar´e (NP) operator appears naturally when we attempt to solve Dirichlet or Neumann boundary value problems using layer potentials. In this talk, we will review some properties of NP-operators and show that they can be used to give a mathematical analysis of cloaking by anomalous localized resonance (CALR). More precisely, we shall discuss the following problem. If a body of dielectric material is coated by a plasmonic structure of negative dielectric constant with nonzero loss parameter, then CALR may occur as the loss parameter tends to zero. Anomalous localized resonance is the phenomenon of field blow-up in a localized region and it may (and may not) …

Cloaking In-Plane Elastic Waves with Swiss Rolls

2020

We propose a design of cylindrical cloak for coupled in-plane shear waves consisting of concentric layers of sub-wavelength resonant stress-free inclusions shaped as Swiss rolls. The scaling factor between inclusions&rsquo

Considerazioni tassonomiche sulle querce caducifoglie della Sicilia

1998

On the basis of literature, herbarium and field investigations, a survey on the species of deciduous oaks occurring in Sicily is presented. A morphological description fitted with photos and drawings and completed by some chorological and ecological observations is reported for each species. Finally it is emphasized that the phenotypical variability observed in Sicily among the Q. pubescens group, even if let to consider the S.Thyrrhenian area as a probable speciation center of the group, on the other hand should also be related to the deforestation, which favoured the genetic mixing among populations.

Immobilisation of yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine

2019

[EN] Sparkling wine production comprises two successive fermentations performed by Sacharomyces cerevisiae strains. This research aimed to: develop yeast immobilisation processes on two wine-compatible supports; study the effects of yeast type (IOC 18-2007 and 55A) and the immobilisation support type (oak chips and cellulose powder) on the fermentation kinetics, the deposition rate of lees and the volatile composition of the finished sparkling wine; compare the fermentation parameters of the wines inoculated with immobilised or non-immobilised cells. Proper immobilisation of yeast on oak chips and cellulose powder was demonstrated by electron microscopy. Total sugar consumption occurred in …

Estimating Mean Lifetime from Partially Observed Events in Nuclear Physics

2022

Abstract The mean lifetime is an important characteristic of particles to be identified in nuclear physics. State-of-the-art particle detectors can identify the arrivals of single radioactive nuclei as well as their subsequent radioactive decays (departures). Challenges arise when the arrivals and departures are unmatched and the departures are only partially observed. An inefficient solution is to run experiments where the arrival rate is set very low to allow for the matching of arrivals and departures. We propose an estimation method that works for a wide range of arrival rates. The method combines an initial estimator and a numerical bias correction technique. Simulations and examples b…

Short-term response to waterlogging in Quercus petraea and Quercus robur: A study of the root hydraulic responses and the transcriptional pattern of …

2015

International audience; We characterized the short-term response to waterlogging in Quercus petraea (Matt.) Liebl. and Quercus robur L. as the initial response towards their known long-term differences in tolerance to waterlogging. One-month old seedlings were subjected to hypoxic stress and leaf gas exchange, shoot water potential (Psi(s)) and root hydraulic conductivity (Lp(r)) were measured. In parallel, the expression of nine aquaporins (AQPs) along the primary root was analysed by quantitative RT-PCR. Results showed a similar reduction in net assimilation (A) and stomatal conductance (g(s)) for the two species. Notably, the response of Lpr differed temporally between the two species. Q…

Komedia tulevaisuuden Suomesta

2005

Carbon stock increases up to old growth forest along a secondary succession in Mediterranean island ecosystems.

2019

The occurrence of old-growth forests is quite limited in Mediterranean islands, which have been subject to particularly pronounced human impacts. Little is known about the carbon stocks of such peculiar ecosystems compared with different stages of secondary succession. We investigated the carbon variation in aboveground woody biomass, in litter and soil, and the nitrogen variation in litter and soil, in a 100 years long secondary succession in Mediterranean ecosystems. A vineyard, three stages of plant succession (high maquis, maquis-forest, and forest-maquis), and an old growth forest were compared. Soil samples at two soil depths (0-15 and 15-30 cm), and two litter types, relatively undec…