Search results for "conservation."
showing 10 items of 1994 documents
Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora
1998
ABSTRACT Cytisus aeolicus Guss, is an endemic plant restricted to the isles of Vulcano, Stromboli and Alicudi in the Aeolian archipelago. All known populations were assayed for genetic variability using enzyme polymorphism. Allozyme variation at 16 loci coding for 10 enzyme systems was examined. The great majority of loci turned out to be monomorphic or fixed heterozygous. The observed genetic depauperation is indicative of historical factors, such as the bottleneck effect associated with migration, and the founder effect in population re-establishment. The low genetic diversity is largely partitioned within rather than among populations, indicating that extant populations have not been est…
A report on the conservation status of segetal weeds in Tajikistan
2014
Summary Intensification of agriculture has significantly diminished the populations of segetal weeds worldwide in recent decades. Remarkable changes to the entire flora and vegetation of man-made habitats are being observed in agroecosystems. The present study analyses, for the first time, the threat status of segetal weeds in Tajikistan. A group of 871 weed species were evaluated against IUCN criteria. The assessment of threat status revealed that 214 weed taxa have to be regarded as threatened in Tajikistan, including 18 endemic and four subendemic plants. Five species have been classified as extinct, 27 as critically endangered, 27 as endangered, 39 as vulnerable, 34 as near threatened a…
First record of Ribes uva-crispa L. (Grossulariaceae) from the Madonie Mts., a new species of the Sicilian flora.
2011
Abstract In this study, a first record of Ribes uva-crispa L. (Grossulariaceae) – a new species of the Sicilian flora – from the Madonie Mts. is reported. The autochthonous and relict new population of Ribes uva-crispa L. (Grossulariaceae) is found on Mount Carbonara (Madonie Mts., North-Central Sicily), which is several hundred kilometers away from the Central Apenninic and the South Mediterranean locations of its distribution range. R. uva-crispa shows a distribution similar to other taxa extending from the Euro-Asiatic area to the mountains of North Africa with disjunct populations on the main Sicilian reliefs (Madonie and Nebrodi Mts.), testifying ancient phytogeographical connections. …
Using the ARP-03 for high-resolution mapping of calcic horizons
2013
A b s t r a c t. The aim of this work is to present a fast and cheap method for high-resolution mapping of calcic horizons in vineyards based on geoelectrical proximal sensing. The study area, 45 ha located in southern Sicily (Italy), was characterized by an old, partially dismantled marine terrace and soils with a calcic horizon at different depths. The geoelectrical investigation consisted of a survey of the soil electrical resistivity recorded with the Automatic Resistivity Profiling-03 sensor. The electrical resistivity values at three pseudo-depths, 0-50, 0-100 and 0-170 cm, were spatialized by means of ordinary kriging. A principal component analysis of the three electrical resistivit…
A simple procedure to improve the pressure evaluation in hydrodynamic context using the SPH
2009
In literature, it is well know that the Smoothed Particle Hydrodynamics method can be affected by numerical noise on the pressure field when dealing with liquids. This can be highly dangerous when an SPH code is dynamically coupled with a structural solver. In this work a simple procedure is proposed to improve the computation of the pressure distribution in the dynamics of liquids. Such a procedure is based on the use of a density diffusion term in the equation for the mass conservation. This diffusion is a pure numerical effect, similar to the well known artificial viscosity originally proposed in SPH method to smooth out the shock discontinuities. As the artificial viscosity, the density…
The role of traditional Erica arborea L. management practices in maintaining northeastern Sicily’s cultural landscape
2007
The tree heath (Erica arborea L.), a small evergreen tree found in the Mediterranean region and parts of Eastern and Central Africa, produces lignotubers that are highly valued for making smoking pipes. The Peloritani Mountains of northeastern Sicily are historically one of the most important areas in Italy for the production of these high quality lignotubers, known as briar root wood. In the past, tree heath shrublands were also an important source of charcoal. Erica arborea utilisation has declined dramatically during the past century, mostly due to the decreasing demand for smoking pipes, as well as the increasing frequency of wildfires and large-scale afforestation activities in this re…
Cogeneration from thermal treatment of selected municipal solid wastes. A stoichiometric model building for the case study on Palermo
2003
This paper aims to calculate the energetic and environmental effects of an integrated solid waste management system in Palermo, Italy. In particular, the thermal treatment of Municipal Solid Waste (MSW) with energy recovery is assessed. The current characterization at the local scale is taken into account. Two different options of collection are taken into account: (1) unselected wastes; and (2) sorted collection, according to the current Italian regulation. Combustion process is analyzed and the following features are calculated: (1) stoichiometric content of air and air excess; and (2) temperature and enthalpy of flue gases. Energy recovery is performed in the hypothesis of Hirn cycle bot…
A ‘TVD-like’ Scheme for Conservation Laws with Source Terms
2008
The theoretical foundations of high-resolution TVD schemes for homogeneous scalar conservation laws and linear systems of conservation laws have been firmly established through the work of Harten [5], Sweby [11], and Roe [9]. These TVD schemes seek to prevent an increase in the total variation of the numerical solution, and are successfully implemented in the form of flux-limiters or slope limiters for scalar conservation laws and systems. However, their application to conservation laws with source terms is still not fully developed. In this work we analyze the properties of a second order, flux-limited version of the Lax-Wendroff scheme preserving steady states [3]. Our technique is based …
New insights on the occurrence and conservation status in Italy of Alessioporus ichnusanus (Boletaceae), an IUCN red listed mycorrhizal species
2020
The conservation status of Alessioporus ichnusanus is discussed considering new insights emerged from the IUCN global assessment. New locations were identified and Italy is confirmed as the center of distribution of this species. According to the IUCN categories and criteria, A. ichnusanus is assigned to the category Vulnerable C2a(i).
Test of the electric charge conservation law with Borexino detector
2015
International audience; The new limit on the electron lifetime is obtained from data of the Borexino experiment. The expected signal from the e → γν decay mode is a 256 keV photon detected in liquid scintillator. Because of the extremely low radioactive background level in the Borexino detector it was possible to improve the previous measurement by two orders of magnitude.