191 research outputs found
Contributo alla conoscenza dei boschi a Quercus ilex della Sicilia
In quest° lavoro vengono esaminati i boschi a Quercus ilex presenti in Sicilia.Oltre alle associazioni in precedenza già osservate per questo territorio, viene segnalata per la prima volta la presenza dell'Ostrio-Quercetum ilicis e inoltre sono descritte alcune nuove subassociazioni relative al Querco-Teucrietum siculi e all'Aceri obtusati-Ostryetum carpintfoliae. Ciascuna associazione viene esaminata sotto il profilo syntassonomico, ecologico e sindinamico.In this paper the Quercus ilex woods occurring in Sicily were examined. Apart from the associations previosly observed in this territory, the presence of Ostryo-Quercetum ilicis is reported for the first time; besides some new subassociations of the Querco-Teucrietum siculi and of the Aceri obtusati-Ostryetum curpinifoliae are described. Syntaxonomic, ecological and syndynamic considerations are given for every association
Originalities of willow of salix atrocinerea Brot. in mediterranean Europe
Willow communities (genus Salix) occurring in Mediterranean Europe are presented,
showing, through statistical treatment with multivariate cluster analysis, the separation of the
di erent plant communities and their sintaxonomic a liation. Six willow communities have been
identified, whose formations include a set of plants with high heritage value. We highlight plants
with legal protection status (Annex IV and II of the Habitats Directive-92/43/EEC), endemic,
rare, and endangered species such as Salix salviifolia subsp. australis, Cheirolophus uliginosus,
Euphorbia uliginosa and Leuzea longifolia. Therefore, two new willow communities are proposed for the
southwest of the Iberian Peninsula. The first dominated by Salix atrocinerea, Frangulo baticae-Salicetum
atrocinereae ass. nova of ribatagan distribution, under acid substrates, thermomediterranean to lower
mesomediterranean, dry to sub-humid. The second, dominated by the endemic Salix salviifolia
subsp. australis, Clematis flammulae-Salicetum australis distributed in the Algarve, developing on
neutral-basic substrates, exclusively thermomediterranous, dry to sub-humid. In both cases, there are
presented on their own floristic serial, ecology, and substitution steps. A new hygrophytic meadows
was also identified dominated by Molinia caerulea subsp. arundinaceae, Cheirolopho uliginosii-Molinietum
arundinaceae ass. new hoc loco, which lives on substrates rich in organic matter, exclusive to the
Ribatagano Sector. Through the deepening of knowledge about the composition and dynamics
of riparian vegetation, it is possible to adapt management methods to sustain and protect these
important edafo-hygrophilic systems in the Mediterranean.info:eu-repo/semantics/publishedVersio
Terrestrial Laser Scanner techniques in the assessment of tsunami impact on the Maddalena peninsula (south-eastern Sicily, Italy)
The coastline of the Maddalena peninsula (south-eastern Sicily, Italy) is characterised by the occurrence of a boulder field associated to an extended soil stripping area and by a gravel/sandy berm. The accumulation of the boulders has been mostly correlated to the impact of the December 28, 1908 tsunami wave. The use of Terrestrial Laser Scanner survey techniques, associated to Differential Global Position System determinations, permits to obtain new data for the assessment of tsunami impact on this coastal area. The computing of the surveyed data using the most recent equations is a useful tool in order to estimate the theoretic inundation limit and to reconstruct its variability in function of the boulders size and of the coastal topography. Moreover, the entire new data set allows to confirm that the hypothesis of the tsunami impact is the most reasonable to explain the occurrence of boulders weighing up to 50 tons on the Maddalena peninsula
New Contributions to the Ericion umbellatae Alliance in the Central Iberian Peninsula
The study of heathlands dominated by Erica australis, E. umbellata and Cistus populifolius in
the centre and west of the Iberian Peninsula allows us to separate the eight shrubland communities.
The taxonomic analysis of E. australis distinguishes two subspecies: E. australis subsp. australis and
E. australis subsp. aragonensis. The statistical treatment confirms the differences between the subal liances Ericenion aragonensis and Ericenion umbellatae. This ecological, bioclimatic, biogeographical
and floristic study has allowed us to differentiate three new associations from the remaining five:
TCp = Teucrio oxylepis-Cistetum populifolii nova. HEau = Halimio ocymoidis-Ericetum australis nova.
DEu = Drosophyllo lusitanicae-Ericetum umbellatae nova. ECp = Erico australis-Cistetum populifolii Ri vas Goday 1964. PCp = Polygalo microphyllae-Cistetum populifolii Rivas Goday 1964. HEa = Halimio
ocymoidis-Ericetum aragonensis Rivas-MartÃnez 1979. HEu = Halimio ocymoidis-Ericetum umbellatae
Rivas Goday 1964. UEu = Ulici eriocladi-Ericetum umbellatae
MIDGARD: A Simulation Platform for Autonomous Navigation in Unstructured Environments
We present MIDGARD, an open-source simulation platform for autonomous robot
navigation in outdoor unstructured environments. MIDGARD is designed to enable
the training of autonomous agents (e.g., unmanned ground vehicles) in
photorealistic 3D environments, and to support the generalization skills of
learning-based agents through the variability in training scenarios. MIDGARD's
main features include a configurable, extensible, and difficulty-driven
procedural landscape generation pipeline, with fast and photorealistic scene
rendering based on Unreal Engine. Additionally, MIDGARD has built-in support
for OpenAI Gym, a programming interface for feature extension (e.g.,
integrating new types of sensors, customizing exposing internal simulation
variables), and a variety of simulated agent sensors (e.g., RGB, depth and
instance/semantic segmentation). We evaluate MIDGARD's capabilities as a
benchmarking tool for robot navigation utilizing a set of state-of-the-art
reinforcement learning algorithms. The results demonstrate MIDGARD's
suitability as a simulation and training environment, as well as the
effectiveness of our procedural generation approach in controlling scene
difficulty, which directly reflects on accuracy metrics. MIDGARD build, source
code and documentation are available at https://midgardsim.org/
Transfer without Forgetting
This work investigates the entanglement between Continual Learning (CL) and
Transfer Learning (TL). In particular, we shed light on the widespread
application of network pretraining, highlighting that it is itself subject to
catastrophic forgetting. Unfortunately, this issue leads to the
under-exploitation of knowledge transfer during later tasks. On this ground, we
propose Transfer without Forgetting (TwF), a hybrid approach building upon a
fixed pretrained sibling network, which continuously propagates the knowledge
inherent in the source domain through a layer-wise loss term. Our experiments
indicate that TwF steadily outperforms other CL methods across a variety of
settings, averaging a 4.81% gain in Class-Incremental accuracy over a variety
of datasets and different buffer sizes.Comment: 22 pages, 3 Figures. Accepted at 17th European Conference on Computer
Vision (ECCV 2022), Tel Aviv, Israe
Morphometric analysis and bioclimatic distribution of Glebionis coronaria s.l. (Asteraceae) in the Mediterranean area
We present a revision of Glebionis coronaria in the Mediterranean area based on: a) micro-morphology
of the disc floret cypselas observed with a high-resolution confocal microscopy; b) measurements of the
disc cypsela with a stereoscopic microscope – duly scaled; c) its distribution in several bioclimatic belts; d)
field observations; e) comparisons of herbarium samples. Because of this study, we propose the elevation
of Glebionis coronaria var. discolor to the rank of species, as Glebionis discolor comb. & stat. nov., based
on morphological and ecological characteristics such as the disposition of the intercostal glands, the size
of the disc cypsela wings and its distribution according to the bioclimatic belts. Glebionis coronaria, with
totally yellow ray florets and intercostal glands aligned, is exclusive to the thermo-Mediterranean bioclimatic
belt, while Glebionis discolor, with white ray florets on a yellow base and intercostal glands arranged
randomly, is found in the thermo- and meso-Mediterranean belt.
Illustrations of micromorphological characteristics of the cypselas, an identification key, a taxonomic
synopsis including information on nomenclatural types, synonyms, descriptions of the taxa, and, as supplementary
information, a list of the specimens examined and bioclimatic classification of samples localities
are also presented
Alien flora in Calabria (Southern Italy): an updated checklist
An updated checklist of the Calabrian alien vascular flora is presented. By way of field, bibliographic, and herbarium research, we recorded 382 alien taxa (representing almost 14% of all regional flora), of which 371 are angiosperms, nine gymnosperms, and two ferns. In relation to the state of spread, the majority of alien species are casual (207 taxa; 54%), followed by naturalized (127; 33%) and invasive (48; 13%), these last include four on the list of Union Concern, sensu Regulation (EU) no. 1143/2014. The most represented families are Asteraceae (39 taxa) and Poaceae (39). Among genera, Amaranthus (nine taxa), Prunus, Euphorbia, and Oxalis (seven taxa) make up those with the greatest number of taxa. A total of 21 taxa were reported for the first time, three of them are new to the European flora (Camptosema rubicundum, Musa xparadisiaca and, only for continental Europe, Ipomoea hederacea), two to the Italian peninsula (Pelargonium graveolens, Schinus terebinthifolia) and 16 to the Calabrian flora (Aeonium arboreum, Asparagus asparagoides, Aspidistra elatior, Bidens sulphurea, Catalpa bignonioides, Citrus xaurantium, Crassula ovata, Cucurbita ficifolia, Dimorphotheca ecklonis, Graptopetalum paraguayense subsp. paraguayense, Kalanchoe laxiflora, Nicotiana tabacum, Phytolacca dioica, Portulaca umbraticola, Talinum paniculatum, Tecomaria capensis). In terms of residence status, there are 291 neophytes (76%), 73 archaeophytes (19%), and 18 regional aliens (5%); neophytes are the most represented group (45 out of 48) among invasive taxa. Concerning life forms, the two most abundant groups are therophytes (30.1%, 115 taxa) and phanerophytes (29.6%, 113 taxa). Regarding habitats, 72% of alien taxa occur in artificial (199 taxa, 52%) and agricultural habitats (75 taxa, 20%). The majority of alien taxa are native to the Americas (159; 41.6%), numerous aliens also originated in Asia (76; 19.9%) and Africa (56; 14.7%). The majority of taxa were introduced for ornamental purposes (55%). Over the past decade, alien taxa in the flora in Calabria have increased from 190 to the current 382 taxa. While this trend could be linked to some extent to increasing awareness of the problem of alien species and the increasing intensity of research over recent decades, it is also most probably due to new introductions resulting from the globalization that relentlessly affects the whole planet.info:eu-repo/semantics/publishedVersio
A multivariate morphometric analysis of diagnostic traits in southern Italy and Sicily pubescent oaks
Species identification within the species complex
of Q. pubescens is a well-known taxonomic challenge
among European botanists. Some of the specific
pubescent oak binomials currently accepted in various
European floras and checklistswere originally described
in Sicily and southern Calabria. As a consequence,
several species belonging to the pubescent oaks group
(Q. pubescens, Q. amplifolia, Q. congesta,
Q. dalechampii, Q. leptobalana and Q. virgiliana) are
reported in the taxonomic and phytosociological literature.
To verify whether it was possible to associate a
diverse set of morphological characters with each of
these different taxa, thirteen natural populations of pubescent
oak from Sicily and southern Calabria were
sampled. A total of 391 trees, 3,887 leaves and 1,047
fruits were collected. Overall, 28 morphological characters
of oak leaves and fruits were statistically analysed
using univariate and multivariate procedures. The results
showed that neither the groups of morphological
diversity identified by cluster analysis, nor those obtained
by our expert identification through the use of analytical
keys, matched with the current taxonomical
frameworks as proposed by the most recent floras and
checklists. Nearly all of the morphological characters
considered displayed a more or less continuous trend of
variation, both within and among populations. In the
light of these findings it seems unlikely that more than
one biological species of pubescent oak occurs in Sicily
and southern Calabria
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