Conferma della presenza di Aphanius fasciatus (Valenciennes, 1821) (Cyprinodontiformes Cyprinodontidae) nel bacino idrografico del Fiume Imera Meridionale (Sicilia)

Un\u2019abbondante popolazione del Ciprinodontide autoctono Aphanius fasciatus \ue8 stata rinvenuta nel Fiume ImeraMeridionale ed in alcuni suoi affluenti. \uc9 cos\uec confermata la persistenza della specie nel sito, nonostante le pesanti alterazioni ambientali che hanno interessato il fiume e che avevano fatto ritenere A. fasciatus localmente estinto. Trattandosi di una delle poche popolazioni di Aphanius fasciatus sopravvissute nei corsi d\u2019acqua siciliani e alla luce della notevole diversit\ue0 genetica e morfologica riscontrata tra le differenti popolazioni siciliane di questo Ciprinodontide, la sopravvivenza di questa popolazione assume un\u2019importante valenza conservazionistica

La biodiversità dei boschi siciliani. Parte I: l’avifauna.

\uc8 stata censita la diversit\ue0 delle specie ornitiche presente in alcune tipologie forestali della Regione Siciliana e la relazione tra le ornitocenosi, le scelte gestionali ed i diversi fattori abiotici e biotici. L\u2019analisi della species richness (= numero delle specie) dimostra che essa \ue8 correlata con il bioclima, il diametro massimo degli individui arborei, il valore trofico di tutti gli strati di vegetazione ed il valore trofico dello strato arboreo. I boschi meso-supramediterranei sono pi\uf9 ricchi di specie rispetto ai boschi termomesomediterranei. L\u2019importanza del diametro massimo degli individui arborei, che esprime indirettamente anche il tipo di gestione di un bosco, viene spiegata dalla dipendenza di alcune specie corticicole da piante di grosse dimensioni e di alcune specie legate a chiome di alberi alti in genere corrispondenti a piante di grosse dimensioni. Il valore trofico dei boschi \ue8 stato censito attraverso un apposito rilievo delle specie floristiche con valore nutritivo presente nello strato erbaceo, arbustivo e arboreo. L\u2019assenza di specie con valore trofico riduce molto le specie di uccelli presenti ma, nello stesso tempo, l\u2019abbondanza di specie floristiche con valore trofico non produce una abbondanza di specie ornitiche. Quando invece della species richness si correla l\u2019indice di diversit\ue0 di Shannon con i fattori suddetti, il risultato \ue8 simile: viene influenzato dal bioclima, dal diametro massimo e dalla presenza di piante con valore trofico. Infine, \ue8 da sottolineare che n\ue9 la species richness n\ue9 l\u2019indice di Shannon risulta essere influenzata dal diametro del legno morto in piedi o dal volume del legno morto a terra. Le indicazioni che risultano dai risultati dell\u2019analisi sono: 1) per aumentare la diversit\ue0 ornitica bisogna lasciare nuclei di piante adulte e di una certa dimensione, anche nei cedui; 2) alla luce dei risultati sulla presenza di specie con valore trofico vanno riviste le norme che prevedono le specie (qualit\ue0 e quantit\ue0) da rilasciare nei cedui; 3) per i rimboschimenti vanno escluse le ripuliture del sottobosco e le spalcature che devono essere limitate alla fascia perimetrale per la prevenzione degli incendi.We collected data on bird diversity in the main Sicilian forest types and related them to silvicultural management and a number of abiotic and biotic factors. The results show that bird species richness is influenced by bioclimate, maximum tree diameter, nutritive value of all vegetation layers. Forests in meso-/supramediterranean bioclimate are richer in species than forests in thermo-/mesomediterranean bioclimate. The importance of maximum tree diameter, which indirectly reflects also the silvicultural management of a forest, is due to the dependency of some corticicolous species on large trees, and of some other bird species on crowns of high trees which have usually large diameters. The nutritive value of a forest was quantified by data sampling: for the herbaceous, shrub and tree layers we recorded all species with nutritive value. The absence of plant species with nutritive value strongly reduces the number of bird species present in a forest; it is, however, noteworthy that an abundance of plant species with nutritive value does not automatically lead to abundant bird species. In addition, it has to be underlined that neither species richness nor Shannon\u2019s diversity index are influenced by the diameter of standing dead wood or by the volume of fallen dead wood. The guidelines which result from our analysis for the silvicultural management of Sicilian forests are: 1) in order to increase bird diversity do not cut large adult trees, also in coppices; 2) leave plants with high nutritive value in coppices; 3) in reforestations do not cut the underbrush and do not prune the lower branches of trees, these actions have to be taken only in the forest edge for wildfire prevention

The cultivable bacterial microbiota associated to the medicinal plant Origanum vulgare L.: from antibiotic resistance to growth-inhibitory properties

The insurgence of antibiotic resistance and emergence of multidrug-resistant (MDR) pathogens prioritize research to discover new antimicrobials. In this context, medicinal plants produce bioactive compounds of pharmacological interest: some extracts have antimicrobial properties that can contrast different pathogens. For such a purpose, Origanum vulgare L. (Lamiaceae family) is a medicinal aromatic plant, whose essential oil (EO) is recognized for its antiseptic, antimicrobial and antiviral activities. The cultivable bacteria from different compartments (i.e., flower, leaf, stem and soil) were isolated in order to: (i) characterize the bacterial microbiota associated to the plant, determining the forces responsible for the structuring of its composition (by evaluation of cross inhibition); (ii) investigate if bacterial endophytes demonstrate antimicrobial activities against human pathogens. A pool of plants belonging to O. vulgare species was collected and the specimen chemotype was defined by hydrodistillation of its essential oil. The isolation of plant associated bacteria was performed from the four compartments. Microbiota was further characterized through a culture-independent approach and next-generation sequencing analysis, as well. Isolates were molecularly typed by Random Amplified Polymorphic DNA (RAPD) profiling and taxonomically assigned by 16S rRNA gene sequencing. Antibiotic resistance profiles of isolates and pairwise cross-inhibition of isolates on agar plates (i.e., antagonistic interactions) were also assessed. High level of diversity of bacterial isolates was detected at both genus and strain level in all different compartments. Most strains were tolerant against common antibiotics; moreover, they produced antagonistic patterns of interactions mainly with strains from different compartments with respect to that of original isolation. Strains that exhibited high inhibitory properties were further tested against human pathogens, revealing a strong capacity to inhibit the growth of strains resistant to several antibiotics. In conclusion, this study regarded the characterization of O. vulgare L. chemotype and of the bacterial communities associated to this medicinal plant, also allowing the evaluation of antibiotic resistance and antagonistic interactions. This study provided the bases for further analyses on the possible involvement of endophytic bacteria in the production of antimicrobial molecules that could have an important role in clinical and therapeutic applications

Effective Regge QCD

A new framework for a high energy limit of quantum gauge field theories is introduced. Its potency is illustrated on a new derivation of the reggeization of the gluon.Comment: Latex, 9 pages + 2 figures as PS-file, extended version, to appear in Phys. Rev. Let

Rapidity gaps and production of minijets in high-energy hadronic collisions

High energy hadronic interactions can produce a final state characterized by minijets separated by a large gap in the rapidity distribution of the produced secondary particles. We discuss the process by keeping into account the possibility of having multiple parton collisions in the hadronic interaction. At Tevatron energy the correction to the single scattering term induced by the presence of multiparton interactions is large for transverse momenta smaller than 6 GeV.Comment: 29 pages, TeX file, 2 figures which are now include

Universality of next-to-leading power threshold effects for colourless final states in hadronic collisions

SCOAP

Systemic importance of financial institutions: regulations, research, open issues, proposals

In the field of risk management, scholars began to bring together the quantitative methodologies with the banking management issues about 30 years ago, with a special focus on market, credit and operational risks. After the systemic effects of banks defaults during the recent financial crisis, and despite a huge amount of literature in the last years concerning the systemic risk, no standard methodologies have been set up to now. Even the new Basel 3 regulation has adopted a heuristic indicator-based approach, quite far from an effective quantitative tool. In this paper, we refer to the different pieces of the puzzle: definition of systemic risk, a set of coherent and useful measures, the computability of these measures, the data set structure. In this challenging field, we aim to build a comprehensive picture of the state of the art, to illustrate the open issues, and to outline some paths for a more successful future research. This work appropriately integrates other useful surveys and it is directed to both academic researchers and practitioners