Search results for " CLUSTER"
showing 10 items of 2162 documents
I TUMORI INFANTILI E DEGLI ADOLESCENTI: TREND DI INCIDENZA E STUDIO DI EVENTUALI CLUSTER. CONFRONTO TRA LE PROVINCE DI PALERMO E DI CALTANISSETTA NEL…
2017
INTRODUZIONE: Nonostante i progressi nelle strategie terapeutiche e il conseguente miglioramento della sopravvivenza, i tumori infantili rappresentano un importante problema di salute pubblica. È stato effettuato un confronto tra l’incidenza dei tumori infantili (0-14 anni) e degli adolescenti (15-19 anni) nelle province di Palermo e di Caltanissetta, nel periodo 2007-2012. MATERIALI E METODI: Sono stati analizzati 453 nuovi casi di tumore maligno e i non maligni del SNC in soggetti <20 anni, registrati dal Registro Tumori di Palermo Provincia (RTPP) e dal Registro Tumori di Ragusa e Caltanissetta (RTRC) tra il 2007 e il 2012. Variazioni delle medie annue percentuali sono state calcolate…
Stark ionization of atoms and molecules within density functional resonance theory
2013
We show that the energetics and lifetimes of resonances of finite systems under an external electric field can be captured by Kohn–Sham density functional theory (DFT) within the formalism of uniform complex scaling. Properties of resonances are calculated self-consistently in terms of complex densities, potentials, and wave functions using adapted versions of the known algorithms from DFT. We illustrate this new formalism by calculating ionization rates using the complex-scaled local density approximation and exact exchange. We consider a variety of atoms (H, He, Li, and Be) as well as the H2 molecule. Extensions are briefly discussed.
Short Term Dynamics of Tourist Arrivals: What Do Italian Destinations Have in Common?
2011
This work aims to detect the common short term dynamics to yearly time series of 413 Italian tourist areas. We adopt the clustering technique of Abraham et al. (Scand J Stat. 30:581–595, 2003) who propose a two-stage method which fits the data by B-splines and partitions the estimated model coefficients using a k-means algorithm. The description of each cluster, which identifies a specific kind of dynamics, is made through simple descriptive cross tabulations in order to study how the location of the areas across the regions or their prevailing typology of tourism characterize each group.
Clustering cities through urban metrics analysis
2017
[EN] This paper describes a process for measuring and characterizing urban morphological zones. These urban zones are delineated for the entire area of Spain, independently of administrative boundaries and excluding demographic data, using a high resolution land-use dataset. Given the rich information available on land cover and subsequently assigned population data, it is possible to calculate a set of urban spatial metrics to classify these urban zones into homogenous morphological groups. Four types of urban agglomerations are identified in Spain by working with these urban metrics and applying a final cluster analysis. Although these groups have a general complex monocentric typology, e…
UV photoexcitation of a dissolved metalloid Ge9 cluster compound and its extensive ultrafast response.
2015
Femtosecond pump-probe absorption spectroscopy in tetrahydrofuran solution has been used to investigate the dynamics of a metalloid cluster compound {Ge9[Si(SiMe3)3]3}(-). Upon UV photoexcitation, the transients in the near-infrared spectral region showed signatures reminiscent of excess electrons in THF (bound or quasi-free) whereas in the visible part excited state dynamics of the cluster complex dominates.
Universal Design for Learning come cornice per l’insegnamento inclusivo. Un’indagine esplorativa tra i futuri docenti di sostegno
2022
Il contributo illustra la seconda fase di una indagine dal titolo Best practices and tools of analysis in schools and community contexts: learning, teaching & inclusion il cui focus è la rilevazione ed il monitoraggio dell’agire educativo dei futuri insegnanti di sostegno in un’ottica inclusiva. Nello specifico, è stato scelto di indagare mediante la somministrazione di un questionario a risposta aperta, costruito a partire dal framework dello Universal Design for Learning, le pratiche messe in atto da insegnanti di sostegno in formazione, in merito ai principi che ne compongono le Linee Guida. Al fine di individuare all’interno del campione, in maniera affidabile e sicura, dei raggrupp…
Characterization of a new member of the sea urchin Paracentrotus lividus hsp70 gene family and its expression
1992
We have sequenced a second gene of the hsp70 family derived from a genomic clone of the sea urchin, Paracentrotus lividus. The structure of this gene, named hsp70IV gene, is interrupted by one intron and differs from the previously analyzed sea urchin hsp70II gene, which contains several introns. Two open reading frames of hsp70IV gene encode a predicted protein of 639 amino acids with an M(r) of 69,672. The 5' flanking region of the gene contains a putative TATA element, three heat-shock elements made up of some arrays of the 5-bp units, NGAAN and NTTCN (N = A,C,G or T), a canonic consensus sequence for binding of the regulatory activating transcription factor (ATF), and a purine box. The …
Electron Delocalization and Electrostatic Repulsion at the Origin of the Strong Spin Coupling in Mixed-Valence Keggin Polyoxometalates: Ab Initio Cal…
2004
International audience; Cet article détaille une procédure générale qui associe l′évaluation de paramètres microscopiques et la prédiction de propriétés macroscopiques. Les principales interactions entre les électrons délocalisés sur des polyoxométalates à valence mixte sont extraites à partir du calcul de la spectroscopie de valence de fragments immergés dans un bain qui reproduit les principaux effets du reste du cristal sur le fragment considéré. Nous avons extrait non seulement la valeur du transfert électronique, du couplage magnétique et du paramètre de "exchange-transfer" entre ions métalliques premiers et seconds voisins, mais encore la valeur de la répulsion électrostatique entre l…
Chemical effect on the XPS spectra of the valence band and on O KLL and Pd MNN Auger spectra in pumice-supported catalysts
1992
X-ray photoelectron spectra of the valence band and X-ray-excited O KLL Auger transition of pumice-supported Pd and Pt catalysts have been obtained and compared to the corresponding spectra of pumice (a naturally occurring amorphous aluminosilicate). The changes observed indicate interaction between metal and support. The valence region of the catalysts consists of three large peaks: one due to the d band of the metals and the other to the O 2p non-bonding orbitals and bonding-type orbitals formed by a mixing of the atomic orbitals (O 2p, Si 3s and Si 3p) of oxygen and silicon from the support. The intensity decrease of the component due to the bonding orbitals, observed in the catalyst spe…
Mixed-Valence Molecular Unit for Quantum Cellular Automata: Beyond the Born-Oppenheimer Paradigm through the Symmetry-Assisted Vibronic Approach.
2016
In this article, we focus on the electron-vibrational problem of the tetrameric mixed-valence (MV) complexes proposed for implementation as four-dot molecular quantum cellular automata (mQCA).1 Although the adiabatic approximation explored in ref 2 is an appropriate tool for the qualitative analysis of the basic characteristics of mQCA, like vibronic trapping of the electrons encoding binary information and cell-cell response, it loses its accuracy providing moderate vibronic coupling and fails in the description of the discrete pattern of the vibronic levels. Therefore, a precise solution of the quantum-mechanical vibronic problem is of primary importance for the evaluation of the shapes o…