Search results for "Tree"
showing 10 items of 1841 documents
An ITS phylogeny of tribe Senecioneae (Asteraceae) and a new delimitation of Senecio L.
2007
Senecioneae is the largest tribe ofAsteraceae, comprised ofca. 150 genera and 3,000 species. Approximately one-third of its species are placed in Senecio, making it one of the largest genera of flowering plants. Despite considerable efforts to classify and understand the striking morphological diversity in Senecioneae, little is known about its intergeneric relationships. This lack ofphylogenetic understanding is predominantly caused by conflicting clues from morphological characters, the large size ofthe tribe, and the absence of a good delimitation of Senecio. Phylogenetic analyses of nrITS and plastid DNA sequence data were used to produce a hypothesis of evolutionary relationships in Se…
The "prodigious" cypress of San Benedetto il Moro
2004
I grandi alberi dei Nebrodi
2012
In questo libro sono presentati i risultati di una ricerca portata avanti dagli Autori, botanici del Dipartimento di Biologia ambientale e Biodiversità dell’Università di Palermo. L’indagine ha riguardato sia ambienti di tipo forestale sia di tipo agricolo tradizionale ed ha messo in luce un ricco patrimonio arboreo di tipo monumentale. Significative sono le immagini relative ai grandi aceri, ai ragguardevoli individui di due specie endemiche dei Nebrodi (Pyrus vallis-demonis e Malus crescimannoi) e al faggio di Fago scuro che rappresenta il patriarca di tutti i faggi d’Italia. Dopo il 150° dell’Unità d’Italia non poteva mancare il Grande Pino piantato in concomitanza dello sbarco di Giusep…
Monumenti della natura: i castagni dell'Etna - Natural monuments: Mount Etna's chestnut trees
2017
L’articolo premette l’importanza che hanno le antiche essenze arboree nel paesaggio italiano. si sofferma poi sulla necessità di un censimento continuo della conoscenza, della conservazione e della loro messa in valore e cita alcune delle normative esistenti nel territorio nazionale. Infine, tra i monumenti dal ‘naturale portento’, il saggio si sofferma sui castagni dell’Etna, che tanta meraviglia hanno suscitato tra i viaggiatori del sec. XVIII e che continuano ancora oggi a stupire ed emozionare. The article addresses the importance of ancient tree crops in the Italian landscape. It dwells on the need for a long-standing census on knowledge, preservation and promotion of these trees and q…
A new species of Ferula (Apiaceae) from Malta
2018
Ferula melitensis, a new species from the Malta Archipelago, is described and illustrated. It belongs to the taxonomic group of F. communis, showing close relationships mainly with F. tunetana, F. arrigonii, F. communis s.str. and F. glauca, from which it differs in several features regarding the stem, leaves (mainly for shape and size of terminal segments), flowers and mericarps; other significant differences regard the ecology and phenology. The investigations, carried out on living plants, herbarium material and literature data, regard the morphological analysis of vegetative and reproductive structures, the anatomy of terminal leaf segments and mericarps, as well as the shape and size o…
Evolution of arginine deiminase (ADI) pathway genes
2002
We have analyzed the evolution of the three genes encoding structural enzymes of the arginine deiminase (ADI) pathway, arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) in a wide range of organisms, including Archaea, Bacteria, and Eukarya. This catabolic route was probably present in the last common ancestor to all the domains of life. The results obtained indicate that these genes have undergone a complex evolutionary history, including horizontal transfer events, duplications, and losses. Therefore, these genes are not adequate to infer organismal relationships at deep branching levels, but they provide an insight into how catabolic genes evolved and …
2021
Studies on the function of PRDM9 in model systems and its evolution during vertebrate divergence shed light on the basic molecular mechanisms of hybrid sterility and its evolutionary consequences. However, information regarding PRDM9-homolog, PRDM7, whose origin is placed in the primate evolutionary tree, as well as information about the fast-evolving DNA-binding zinc finger array of strepsirrhine PRDM9 are scarce. Thus, we aimed to narrow down the date of the duplication event leading to the emergence of PRDM7 during primate evolution by comparing the phylogenetic tree reconstructions of representative primate samples of PRDM orthologs and paralogs. To confirm our PRDM7 paralogization patt…
Whole mitochondrial genomes unveil the impact of domestication on goat matrilineal variability
2015
Background The current extensive use of the domestic goat (Capra hircus) is the result of its medium size and high adaptability as multiple breeds. The extent to which its genetic variability was influenced by early domestication practices is largely unknown. A common standard by which to analyze maternally-inherited variability of livestock species is through complete sequencing of the entire mitogenome (mitochondrial DNA, mtDNA). Results We present the first extensive survey of goat mitogenomic variability based on 84 complete sequences selected from an initial collection of 758 samples that represent 60 different breeds of C. hircus, as well as its wild sister species, bezoar (Capra aega…
Multiple-attribute decision support system based on fuzzy logic for performance assessment
2005
Abstract This paper deals with the problem of assessing the performance of a set of production units, simultaneously considering different kinds of information, yielded by a Data Envelopment Analysis, a qualitative data analysis and an expert assessment. The tool for integrating heterogeneous data is a model that applies fuzzy logic to decision support systems. The results obtained are a holistic performance assessment of each unit of the set and a ranking order of the units.
The Random Neural Network Model for the On-line Multicast Problem
2005
In this paper we propose the adoption of the Random Neural Network Model for the solution of the dynamic version of the Steiner Tree Problem in Networks (SPN). The Random Neural Network (RNN) is adopted as a heuristic capable of improving solutions achieved by previously proposed dynamic algorithms. We adapt the RNN model in order to map the network characteristics during a multicast transmission. The proposed methodology is validated by means of extensive experiments.