183 research outputs found
3-Quasi-Sasakian manifolds (Erratum to vol 33, pg 397, 2008)
No full textWe correct the results in section 6 of [B. Cappelletti Montano, A. De Nicola, G. Dileo, 3-Quasi-Sasakian manifolds, Ann. Global Anal. Geom. 33 (2008), 397-409], concerning the corrected energy of the Reeb distribution of a compact 3-quasi-Sasakian manifold. The results are slightly different than what was originally claimed and they are obtained by using results in [B. Cappelletti Montano, A. De Nicola, G. Dileo, The geometry of a 3-quasi-Sasakian manifold, Int. J. Math., to appear, arXiv:0801.1818], where the geometry of these manifolds is more deeply investigated
Correction to: Biodegradation of naphthenic acids: identification of Rhodococcus opacus R7 genes as molecular markers for environmental monitoring and their application in slurry microcosms
No full textThe published online version contains mistake in the author list for the author “M. Cappelletti” was incorrectly presented
Nearly Sasakian geometry and -structures
No full textWe carry on a systematic study of nearly Sasakian manifolds. We prove that
any nearly Sasakian manifold admits two types of integrable distributions with
totally geodesic leaves which are, respectively, Sasakian or -dimensional
nearly Sasakian manifolds. As a consequence, any nearly Sasakian manifold is a
contact manifold. Focusing on the -dimensional case, we prove that there
exists a one-to-one correspondence between nearly Sasakian structures and a
special class of nearly hypo -structures. By deforming such a
-structure one obtains in fact a Sasaki-Einstein structure. Further we
prove that both nearly Sasakian and Sasaki-Einstein -manifolds are endowed
with supplementary nearly cosymplectic structures. We show that there is a
one-to-one correspondence between nearly cosymplectic structures and a special
class of hypo -structures which is again strictly related to
Sasaki-Einstein structures. Furthermore, we study the orientable hypersurfaces
of a nearly K\"{a}hler 6-manifold and, in the last part of the paper, we define
canonical connections for nearly Sasakian manifolds, which play a role similar
to the Gray connection in the context of nearly K\"{a}hler geometry. In
dimension we determine a connection which parallelizes all the nearly
Sasakian -structure as well as the torsion tensor field. An analogous
result holds also for Sasaki-Einstein structures.Comment: We have shortened the introduction and corrected some misprint
Le chiavi del Paradiso. Primato petrino e devozione mariana di Sisto IV tra Cappella Sistina e S. Maria della Pace
No full textIl volume è strutturato in due parti distinte con una postfazione, un indice dei nomi e n. 55 Tavole a colori fuori testo, valide per entrambe le parti del volume. I. PARTE (di Lorenzo Cappelletti) A partire dalla esplicita indicazione che l’ignoto architetto, collocato sul fianco destro dell’affresco sistino della Consegna delle chiavi di Perugino, fa dell’edificio a pianta centrale che campeggia sullo sfondo, viene operata una completa rilettura iconografica e iconologica dell’intero affresco. Tenendo conto di tutta la migliore bibliografia sul tema e grazie anche alla considerazione di fonti inedite o mai considerate in relazione a tale affresco –– vengono riletti in particolare i due episodi evangelici sullo sfondo, la teoria dei dodici apostoli e dei personaggi dell’attualità di fine Quattrocento e soprattutto il gesto della consegna delle chiavi a Simon Pietro da parte di Gesù.
La rilettura si allarga necessariamente anche alla Punizione di Core, Datan e Abiram, l’affresco di Botticelli posto in chiave tipologica dirimpetto alla Consegna delle chiavi, e alla serie dei 30/32 papi affrescati nel cleristorio.
Lo studio non manca di offrire inoltre spunti per una comprensione più adeguata anche degli altri affreschi quattrocenteschi della sistina. II PARTE (di Simona Benedetti) Nell’ambito della revisione di lettura iconologica e iconografica dell’affresco della Consegna delle chiavi di Perugino nella Cappella Sistina, svolta da Lorenzo Cappelletti, si torna a riflettere anche sul significato dell’architettura dell’edificio rappresentato al centro dell’affresco. In questo senso nel contributo di Simona Benedetti, in primo luogo, si ripercorrono i riferimenti alla trattatistica quattrocentesca in materia di edifici sacri, che possono aver influito nella determinazione dell’edificio ottagonale.
In seconda istanza, si considerano le principali fabbriche a pianta ottagonale costruite precedentemente all’edificio dipinto, che possono aver costituito un fondato riferimento per il Perugino nella Consegna delle chiavi.
In particolare tra le architetture, che possono avere avuto un’influenza determinante nella definizione iconografica della fabbrica ottagonale presente nell'affresco, la chiesa di S. Maria della Pace è quella su cui si concentra il presente studio. L'opera si realizzò nel cuore pulsante della Roma rinascimentale proprio contemporaneamente all’affresco in esame, con esso trova degli innegabili punti di tangenza e corrispondenze, sia storiche che figurative. A questo riguardo interessantissima risulta la connessione tra il motivo dell’edificazione della fabbrica e i fatti storici, i personaggi, gli eventi prodigiosi e le pratiche devozionali, che condizionarono lo svolgersi del cantiere del Templum Pacis negli ultimi anni del pontificato di Sisto IV. La storicità del gesto della consegna delle chiavi a Pietro - avvenimento che si protrae nel tempo ad ogni elezione pontificia nello spazio fisico della Cappella Sistina - costituisce la centralità del messaggio iconografico dell'affresco del Perugino in cui, anche l’architettura, insieme ai personaggi rappresentati, strutturano una narrazione reale, estranea alle simbologie decontestualizzate dall’epoca propriamente sistina. Segue una postfazione di Francesco Andreani dal titolo Enigma del Quattrocento, saggio nel quale si sviluppano considerazioni sulle personalità degli architetti e maestranze attive nella Roma del tardo Quattrocento e negli anni di inizio della fabbrica di S. Maria della Pace. Il volume si conclude con l'indice dei nomi (a cura di Gemma Fusciello)I (of Lorenzo Cappelletti) Starting from the unknown architect’s forefinger pointed to the central plan building found in the background of the Sistine Perugino’s fresco The Keys of the Kingdom of Heaven, the author offers a new interpretation of the entire fresco at both an iconographical and iconological level.
Having considered the most important studies about this fresco and taking into account a number of unpublished and unconsidered sources, the author rereads in particular the meaning of the central plan building, as well as the two Gospel episodes in the background; and he rereads also the grouping of the Twelve, along with the fifteenth century historical personages painted among them, in the foreground.
The author’s vision necessarily broodens also to comprehend Botticelli’s fresco named The Punishment of Corah, Dathan and Abiram which is placed on the opposite wall as a typological prefiguration of The Keys of the Kingdom of Heaven; and it broodens moreover to reconsider the series of 30/32 popes frescoed in the upper register of the Sistine Chapel.
The essay also offers hints for a more complete comprehension of the other fifteenth century frescoes of the Sistine Chapel.
II. (of Simona Benedetti) As part of the review of iconological and iconographic reading about the fresco of the “Delivery of the keys” by Perugino in the Sistine Chapel, conducted by Lorenzo Cappelletti, you go back and think about the significance of the building architecture depicted in the center of the fresco. In this sense, the contribution of Simona Benedetti, first, retraces the references to the fifteenth-century treatises concerning sacred buildings, which may have affected the determination of the octagonal building. Secondly, we consider the main factories octagonal building constructed previously painted, that may have been an established reference for the Perugino in the “Delivery of the keys”. Especially between architectures, which may have had a decisive influence in defining the iconographic factory octagonal present in the fresco, the church of St. Mary of Peace is the one on which this study focuses. The work was realized in the heart of Renaissance Rome just simultaneously fresco concerned, although it is undeniable points of contact and correspondence, both historical and figurative. In this regard are interesting connections between the reason of building the factory, the historical facts, the characters and the miraculous events and devotional, which has conditioned the unfolding of the construction site of the Templum Pacis in the last years of the pontificate of Sixtus IV. The historicity of the act of handing over the keys to Peter, that continues over time in the physical space of the Sistine Chapel, is the centrality of the iconographic message of the fresco by Perugino; so even the architecture, along with the characters represented, the real narrative structure, far from to the symbolism belonging to the Sistine period properly
Biochemical properties of human D-amino acid oxidase variants and their potential significance in pathologies
No full textThe stereoselective flavoenzyme D-amino acid oxidase (DAAO) catalyzes the oxidative deamination of neutral and polar D-amino acids producing the corresponding a-keto acids, ammonia, and hydrogen peroxide. Despite its peculiar and atypical substrates, DAAO is widespread expressed in most eukaryotic organisms. In mammals (and humans in particular), DAAO is involved in relevant physiological processes ranging from D-amino acid detoxification in kidney to neurotransmission in the central nervous system, where DAAO is responsible of the catabolism of D-serine, a key endogenous co-agonist of N-methyl-D-aspartate receptors. Recently, structural and functional studies have brought to the fore the distinctive biochemical properties of human DAAO (hDAAO). It appears to have evolved to allow a strict regulation of its activity, so that the enzyme can finely control the concentration of substrates (such as D-serine in the brain) without yielding to an excessive production of hydrogen peroxide, a potentially toxic reactive oxygen species (ROS). Indeed, dysregulation in D-serine metabolism, likely resulting from altered levels of hDAAO expression and activity, has been implicated in several pathologies, ranging from renal disease to neurological, neurodegenerative, and psychiatric disorders. Only one mutation in DAO gene was unequivocally associated to a human disease. However, several single nucleotide polymorphisms (SNPs) are reported in the database and the biochemical characterization of the corresponding recombinant hDAAO variants is of great interest for investigating the effect of mutations. Here we reviewed recently published data focusing on the modifications of the structural and functional properties induced by amino acid substitutions encoded by confirmed SNPs and on their effect on D-serine cellular levels. The potential significance of the different hDAAO variants in human pathologies will be also discussed
Analysis of the Gender Pay Gap in the Italian Labour Market
No full textGender inequality is a complex and multidimensional phenomenon. In recent decades, its measurement has become a focus of interest not only for academic researchers, but also for political institutions and policy makers. However, due to the epidemic from Covid-19, the advancement of gender equality has faced multiple setbacks, especially in the labour market. The objective of this study is to support the implementation of policy makers' strategies and to contribute to the existing literature by shedding light on the importance of quantifying the impact of certain key characteristics related to the workplace and to the individual on the gender pay gap. In particular, we focus on the Italian job market, exploring the phenomenon using updated official statistics data coming from Istat by means of a regression analysis. This study shows how workers are treated differently on the basis of the demographic group to which they belong, providing also an in-depth knowledge of key determinants behind women discrimination in the labour market
Un racconto allegorico-satirico sulla polemica Maffei-Voltaire: «La naissance de Clinquant»
No full textLa messa in scena della Merope voltairiana segna l’inizio di una polemica con l’autore della prima Merope settecentesca, Maffei. Tra i molti scritti polemici, si intende analizzare la favola satirica di Claude Godard D’Aucour, «La Naissance de Clinquant», tradotta anche in italiano. Principale argomento dell’intervento sarà l’uso satirico della favola nella tradizione francese e in quella italiana, e la sua interazione con il testo teatrale che in essa viene irriso, insieme al suo autore
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