Search results for "η"
showing 10 items of 20 documents
Donation and back-donation in cis- and trans-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2 tautomers: Which relative is more generous? An ETS-NOCV bond analysis
2022
The ETS-NOCV bond analysis has been exploited to quantitatively estimate donation and back-donation properties of [(η5-C5H5)]−, CO, and FeI in the cis-/trans-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2 (cis-I/trans-I) tautomers. Theoretical outcomes indicate that the Fe-CO bond, regardless to the CO monoapto (η1-) or bridging (μ-) coordination, has a sizeable π Fe → CO back-bonding contribution, which is stronger in trans-I than in cis-I. Moreover, [(η5-C5H5)]− has the weakest back-donation acceptor capability. The back-bonding behaviour of the Fe → η1-CO interaction well agrees with the experimental symmetric/antisymmetric infrared νCO (sνηjavax.xml.bind.JAXBElement@fc12185-CO/aνηjavax.xml.bind.JAXBElemen…
Approximate fixed points of set-valued mapping in b-metric space
2016
We establish existence results related to approximate fixed point property of special types of set-valued contraction mappings, in the setting of b-metric spaces. As consequences of the main theorem, we give some fixed point results which generalize and extend various fixed point theorems in the existing literature. A simple example illustrates the new theory. Finally, we apply our results to establishing the existence of solution for some differential and integral problems.
On fixed points for a–n–f-contractive multi-valued mappings in partial metric spaces
2015
Recently, Samet et al. introduced the notion of α-ψ-contractive type mappings and established some fixed point theorems in complete metric spaces. Successively, Asl et al. introduced the notion of αӿ-ψ-contractive multi-valued mappings and gave a fixed point result for these multivalued mappings. In this paper, we establish results of fixed point for αӿ-admissible mixed multivalued mappings with respect to a function η and common fixed point for a pair (S; T) of mixed multi-valued mappings, that is, αӿ-admissible with respect to a function η in partial metric spaces. An example is given to illustrate our result.
La Ριμάδα κόρης και νέου e i Contrasti italiani
2017
Viene effettuato un confronto tra La Ριμάδα κόρης και νέου (contrasto greco presente in due manoscritti del XV secolo) e i Contrasti italiani di età precedente o anche contemporanei (da Cielo d'Alcamo a Leonardo Giustinian) A comparison is made between La Ριμάδα κόρης και νέου (Greek contrast present in two 15th century manuscripts) and the Italian Contrasts of previous or even contemporary age (from Cielo d'Alcamo to Leonardo Giustinian)
Document Word Clouds: Visualising Web Documents as Tag Clouds to Aid Users in Relevance Decisions
2009
Περιέχει το πλήρες κείμενο Information Retrieval systems spend a great effort on determining the significant terms in a document. When, instead, a user is looking at a document he cannot benefit from such information. He has to read the text to understand which words are important. In this paper we take a look at the idea of enhancing the perception of web documents with visualisation techniques borrowed from the tag clouds of Web 2.0. Highlighting the important words in a document by using a larger font size allows to get a quick impression of the relevant concepts in a text. As this process does not depend on a user query it can also be used for explorative search. A user study showed, th…
Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections
2016
The double polarization observable E and the helicity dependent cross sections σ1=2 and σ3=2 were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The almost 4π detector setup of the Crystal Ball and TAPS is ideally suited to detect the recoil nucleons and the decay photons from η → 2γ and η → 3π0. The results show that the narrow structure previously observed in η photoproduction from the neutron is only apparent in σ1=2 and hence, most likely related to a spin-1=2 amplitude. Nucleon resonances t…
Measurement of the transverse target and beam-target asymmetries in η meson photoproduction at MAMI
2014
We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the $\vec \gamma \vec p\to\eta p$ reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of $\eta$ meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.
Narrow Structure in the Excitation Function of eta Photoproduction off the Neutron
2013
The photoproduction of $\eta$-mesons off nucleons bound in $^2$H and $^3$He has been measured in coincidence with recoil protons and recoil neutrons for incident photon energies from threshold up to 1.4 GeV. The experiments were performed at the Mainz MAMI accelerator, using the Glasgow tagged photon facility. Decay photons from the $\eta\rightarrow 2\gamma$ and $\eta\rightarrow 3\pi^0$ decays and the recoil nucleons were detected with an almost $4\pi$ electromagnetic calorimeter combining the Crystal Ball and TAPS detectors. The data from both targets are of excellent statistical quality and show a narrow structure in the excitation function of $\gamma n\rightarrow n\eta$. The results from…
La poesia “Il cavaliere e la morte” di Nikos Gatsos. Traduzione e analisi
2000
Traduzione e analisi della poesia Ο ιππότης και ο θάνατος
The transformation of classical paradigms in a debated Christian tragedy
2018
Resumen: A pesar de haber sido publicada en una traducción del original griego al castellano hace 30 años, la Pasión de Cristo, una tragedia-centón atribuida en la tradición manuscrita a Gregorio de Nacianzo, ha recibido escasa atención por parte de la literatura científica hispanófona. En nuestro articulo deseamos proponer algunas reflexiones que puedan contribuir al largo debate relativo a una obra problemática en cuanto a la determinación de su autoría y datación, haciendo hincapié en algunos aspectos que evidencian su singularidad formal y de contenido, subrayando su lograda síntesis entre cultura clásica y sensibilidad cristiana. Abstract: Despite having been published in a translation…