131,695 research outputs found
La transcultura tra narrazione pubblica e privata.
No full textA una trattazione introduttiva dei concetti chiave sottesi all’architettura del
volume è dedicato il saggio di Raffaela Merlini. Prendendo le mosse dal modello
“multiculturalista”, l’autrice ne traccia il superamento, soffermandosi su potenzialità
e criticità dell’approccio “interculturale”, nel quale la logica oppositiva viene
abbandonata a favore di un’ottica di complementarietà delle identità culturali. Ulteriore
evoluzione si ha con la nozione di “transcultura”, fondata sulla disgregazione
delle tradizionali categorie di etnia e cultura, e sulla condizione di permanente
interconnettività derivante dagli attuali processi di rilocalizzazione territoriale
e ibridazione identitaria. Innestando la transcultura sull’impianto teorico della
“narrazione”, nella seconda parte del contributo l’autrice procede a evidenziare,
attraverso esempi tratti per lo più dall’ambito della conversazione istituzionale linguisticamente
mediata, le tensioni che scaturiscono dal disallineamento tra storia
personale e discorso socio-politico. Esplorato nelle sue dimensioni più produttive
e, al tempo stesso, problematizzato, il binomio transcultura/narrazione accoglie al suo interno un duplice sguardo, rivolto sia all’universalità dei valori umani sia
all’unicità dei percorsi individuali, attraverso il quale contrastare gli effetti deteriori
di un appiattimento infantilizzante e del relativismo ideologico
Liminalità e interpretazione: sconfinamenti tra posizioni interazionali e piani comunicativi
No full textThe study aims to investigate whether the media interpreter’s professional
profile, with its high degree of autonomous agency and empathic
involvement, also characterizes interpreting practice in the field of international
film festivals. the analysis is conducted on a set of real-life interactional
data – transcribed audio- and video-clips – from the 47th edition of
the giffoni film festival, and draws upon the interplay between different
theoretical constructs; namely, the concepts of role, discourse and positioning
(davies, harré 1990; harré, van Langenhove 1999) as combined by
henriksen (1998), and the notion of audience design (bell 1984; 1991) and
interaction levels as applied to interpreter-mediated interaction by merlini
(2017). account is taken of the impact of the following contextual factors:
both the jury and the audience of the giffoni film festival are entirely
made up of children and teenagers; and the majority of events are streamed
live. findings reveal that the interpreter tends not to take autonomous initiatives,
and steps into non-normative positions only if instructed or authorized
to do so by primary participants. in the specific context under study,
the interpreter’s role can thus be described as a liminal one, displaying the
imprecise and unsettled contours of transitoriness
The behavior at non-ambient conditions of colemanite: a hydrous Ca-borate
No full textColemanite, CaB3O4(OH)3·H2O, is a common hydrous borate of large economic relevance, as it is one of the major commodities of boron with applications in the fields of glass and ceramic industries. Colemanite-rich layers are usually found in stratigraphic successions related to lacustrine basins in semi-arid to arid environments, associated to a local volcanic activity, which provides the source for boron. Despite the large economic relevance, the behavior of this mineral at non-ambient conditions of temperature and pressure was almost unexplored, which can provide a basis for understanding its stability during diagenetic and metamorphic processes. In this contribution, we report the highpressure behavior of colemanite (Lotti et al., 2017), based on in situ single-crystal synchrotron X-ray diffraction data up to 24 GPa, and its low-T behavior by in situ X-ray and neutron single-crystal diffraction. Colemanite was found to be stable up ~ 14.5 GPa, where a reconstructive phase transition towards a high-pressure polymorph (colemanite-II) with same symmetry (space group P21/a), but a six times larger unit cell volume, occurs. The elastic behavior of colemanite was described by fitting the experimental data with a III-order Birchurnaghan equation of state, yielding the following refined elastic parameters: KV0 = 64(4) GPa and KV' 5.5(7). The colemanite-tocolemanite-II phase transition induces an increase in the average coordination number of both the Ca and B cations. In particular, a fraction of the boron sites increases its coordination from triangular to tetrahedral by making a further bond with a H2O-oxygen atom. Although the phase transition occurs (at ambient temperature) at pressures far from those associated with the usual geologic environments of colemanite, the reported results disclosed flexible deformation mechanisms that borate compounds may adopt to accommodate pressure, thus providing new insights on the behavior of borate minerals at non-ambient conditions. The complex hydrogen-bonding network of olemanite has also been characterized, at ambient and low temperature conditions, by means of in situ single-crystal synchrotron X-ray and neutron diffraction experiments. A positional disorder, related to the presence of two mutually exclusive configurations of the H2O-molecule hydrogen atoms, was found both above and below ~ 0°C, where a displacive phase transition from the P21/a to the P21 space group occurs.
Lotti, P., Gatta, G.D., Comboni, D., Guastella, G, Merlini, M., Guastoni, A., Liermann, H.-P. (2017): High-pressure behavior and Pinduced phase transition of CaB3O4(OH)3*H2O (colemanite), J. Am. Ceram. Soc., in press, DOI: 10.1111/jace.14730
Current status of activation markers in ischemic heart disease: Markers of coagulation activation
No full text
Asymmetric synthesis of 3-methyl-2-phenyl-1,4-benzodioxanes. Absolute configuration of the neolignans eusiderin and eusiderin C and D
No full textThe asymmetric synthesis of 2S,3S- and 2R,3S-3-methyl-2-phenyl-1,4- benzodioxane from (-)-ephedrine is reported. Comparison of the c.d. curves of these compounds with those of the natural neolignans eusiderin and eusiderin C allows the assignment of 2R,3R configuration to eusiderin and of 2R,3S configuration to eusiderin C and eusiderin D
T- and P-stability and thermo-elastic behavior of the ABW-compounds TlAlSiO4 and CsAlSiO4
No full textT- and P-stability and thermo-elastic behavior
of the ABW-compounds TlAlSiO4 and CsAlSiO4
Paolo Lotti,a G. Diego Gattaa,b, Domenico Caputoc, Marco Merlinia,
Paolo Apreac, Andrea Lausid, Carmine Colellac
aDipartimento di Scienze della Terra, Università degli Studi di Milano, Milano, Italy
bCNR - Istituto di Cristallografia, Sede di Bari, Bari, Italy
cDipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli “Federico II”, Napoli, Italy
dSincrotrone Trieste S.C.p.A. di Interesse Nazionale, Basovizza, Trieste, Italy
[email protected]
A large number of microporous compounds sharing the ABW framework topology have so far been reported in the literature. These compounds show a significant chemical variability, leading to interesting magnetic, optical or structural properties (see e.g. [1] and references therein). The ABW framework can be described as made by sheets of six-membered rings of tetrahedra, in which three tetrahedra have apical oxygen atoms pointing upward (U) and three downward (D), according to a “UUUDDD” scheme. The sheets are interconnected through the apical oxygen atoms, giving rise to elliptical 8-membered ring channels, where the extraframework population is hosted. The latter is generally represented by monovalent cations, with (as Li-ABW) or without (as Rb-, Cs- or Tl-ABW) H2O molecules. Only a few studies have so far been devoted to the phase-stability fields and thermo-elastic behavior of ABW compounds, in response to T and P.
In this study, we focused our attention to two synthetic ABW compounds: TlAlSiO4 and CsAlSiO4, which gain interest for the pollutant and/or toxic nature of the hosted extraframework cations (Tl+ or Cs+). TlAlSiO4 has been investigated up to 950 °C (at room-P) and up to 8 GPa (at room-T) by means of in-situ synchrotron powder diffraction with a diamond anvil cell and with a high-temperature furnace [2]. No phase transition has been observed within the T- and P-range investigated. A II-order Birch-Murnaghan equation of state (II-BM EoS) fit of the P-V data led to a refined bulk modulus KV0 = 48.8(2) GPa. A polynomial fit of the T-V data led to a refined volume thermal expansion coefficient αV,25°C = 4.44(3)*10-5 K-1. CsAlSiO4 has been investigated up to 1000 °C (at room-P) and up to 10 GPa (at room-T) by means of in-situ synchrotron powder diffraction [3]. As for the Tl-analogue, no phase transitions have been observed within the T- and P-range investigated. A II-BM EoS fit of the P-V data gave a refined KV0 = 41.3(3) GPa. A polynomial fit of the T-V data led to a refined αV,20°C = 3.63(1)*10-5 K-1. Both the studied ABW-compounds show a remarkably anisotropic thermo-elastic pattern, resembling that of “layered materials” (e.g. phyllosilicates), where the stacking direction of the 6mR-sheets is significantly more compressible and expandable than the sheets plane. Such a behavior appears to be governed by the nature of the ABW topology of the framework. The high stability and flexibility of TlAlSiO4 and CsAlSiO4 at high-T (at room-P) and high-P (at room-T) suggest these compounds as functional materials for the fixation and storage of the Tl+ and Cs+.
[1] V. Kahlenberg, R.X. Fischer, W.H. Baur, Z. Kristallogr. 2001, 216, 489-494.
[2] G.D. Gatta, P. Lotti, M. Merlini, D. Caputo, P. Aprea, A. Lausi, C. Colella, Micropor. Mesopor. Mater. 2014, submitted.
[3] G.D. Gatta, M. Merlini, P. Lotti, A. Lausi, M. Rieder, Micropor. Mesopor. Mater. 2013, 163, 147-152
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