1,265 research outputs found
Modular microporous minerals: cancrinite-davyne group and C-S-H phases
No full textIn this chapter, we illustrate and discuss two distinct groups of microporous phases: the
cancrinite group and the C-S-H compounds of the tobermorite and gyrolite families. The
compounds in the fi rst group present a three-dimensional purely tetrahedral framework with,
apart from a single exception, Si:Al ratio equal to 1; in the mineralogical classifi cations they
are included among feldspathoids and are generally “regarded ...... distinct from zeolites,
in part, at least, because of the presence of large volatile anions” (Coombs et al. 1998). The
members of the second group are characterized by mixed frameworks built up by silicon (and aluminum) tetrahedra and calcium polyhedra. A common feature of both groups is the modular
character of their frameworks, which are built up through various stacking ways of a single module (as in the minerals of the cancrinite-davyne family) and two or more modules as in the case of the C-S-H phases
Superstructure of moraesite: a synchrotron study
No full textMoraesite (Lindberg et al., 1953) is a hydrated berillophosphate with ideal chemical formula Be2(PO4)(OH)·4H2O. Its structure has been known since 1992 (Merlino & Pasero, 1992) and refined in the space group C2/c, a = 8.553(6) Å, b = 12.319(6) Å, c = 7.155(8) Å, β = 97.93(9)°. The main structural feature of moraesite is the presence of large structural cavities occupied by water molecules. The latter are implicated in a complex system of hydrogen bonds where two possible hydrogen bond schemes are equally possible. Few very weak superstructure reflections were observed (Merlino & Pasero, 1992), indicating that the true unit cell of moraesite was probably three times larger, with a b parameter of 36.96 Å and space group symmetry Cc. It was suggested by the authors that the ordering of the hydrogen bond system, concerted with minor adjustments of the structure, could be responsible for the triplication of the b axis. X-ray diffraction data, more recently obtained through synchrotron radiation, confirmed the occurrence of superstructure reflections which were indexed on the basis of an unit cell with tripled b axis. The superstructure of moraesite (a = 8.572(3) Å, b = 36.971(8) Å = 3 x bsub, c = 7.153(2) Å, β = 97.72(1)°, space group Cc) was refined up to R = 0.081 for 1789 unique reflections with Fo > 4sigma(Fo) and 0.0906 for all 2088 data. The structural refinement confirmed that the triplication of the parameter b is due to the ordering of the two possible hydrogen bonding schemes.
1) Lindberg M.L., Pecora W.T. & Barbosa A.L.M. (1953) - Moraesite, a new hydrous beryllium phosphate from Minas Gerais, Brazil. American Mineralogist, 38, 1126-1133.
2) Merlino S. & Pasero M. (1992) - Crystal chemistry of beryllophosphates: The crystal structure of moraesite, Be2(PO4)(OH)·4H2O, Zeitschrift für Kristallographie, 201, 253-262
The Tobermorite-Like Layer in Non-Tobermorite Minerals
No full textThe tobermorite-like layer (TLL) is a characteristic feature in all the structures of the natural and synthetic compounds of the tobermorite group /1/. In those structures eptahedra of calcium cations, characterized by ‘a pyramidal part on one side and a dome part on the other side joining the equatorial oxygen atoms’, form columns through edge sharing; the columns are connected each other, once again through edge sharing, and adjacent columns present the pyramidal apical ligands on opposite sides of the resulting infinite layers. These layers, decorated with wollastonite chains on both sides, build up the ‘complex layers’ which are the basic structural module in all the phases of the tobermorite group (Fig. 1). TLL is a recurrent feature in several natural phases belonging to distinct mineral groups. In the structures of the compounds of the rinkite group the TLL is decorated on both sides by disilicate groups and is accompanied by an infinite ‘octahedral’ layer in building up the structural arrangement. Dovyrenite /2/ and roumaite /3/ are closely related to the minerals of the rinkite group and differ only in the way of decoration of the TLL by the disilicate groups. Fukalite /4/ too presents the TLL, decorated on both sides by four-repeat silicate chains and carbonate groups; tilleyite-type polyhedral layers are also present as distinct modules in building up the structural arrangement. The ubiquitous occurrence of TLL is related to its chemical and structural flexibility: the chemical and geometrical variations of the TLL in the different structures are described and discussed. Key-words: layered silicates, crystal structures, mineralogical crystallography. References /1/ Merlino S., Bonaccorsi E., Armbruster T. (1999): American Mineralogist, 84, 1613–1621. /2/ Kadiyski M., Armbruster T., Galuskin E.V., Pertsev N.N., Zadov A.E., Galuskina I.O., Wrzalik R., Dzierżanowski P., Kislov E.V. (2008): American Mineralogist, 93, 456-462. /3/ Biagioni C., Bonaccorsi E., Merlino S., Parodi G.C., Perchiazzi N., Chevrier V. (2008): Plinius, 34, 211. /4/ Merlino S., Bonaccorsi E., Grabezhev A.I., Zadov A.E., Pertsev N.N., Chukanov N.V. (2009): American Mineralogist, 94, 323–333
Initiatives topicales du client aphasique au cours de séances de rééducation : pratiques interactionnelles et enjeux identitaires
No full textCe chapitre porte sur des séances de rééducation orthophonique de clients aphasiques. Nous analysons l’interaction entre orthophoniste et locuteur aphasique en la concevant comme une activité à la fois institutionnelle et thérapeutique, dont les caractéristiques organisationnelles et les enjeux identitaires peuvent être décris grâce aux outils de l’analyse conversationnelle d’inspiration ethnométhodologique. De manière plus spécifique, l’étude se focalise sur les phénomènes de parler topical et des initiatives topicales du client aphasique. Nous montrons qu’au cours des séances de rééducation à la parole, et notamment au cours de la réalisation des tâches proposées par le thérapeute, le client peut initier des topics conversationnels inspirés des stimuli visuels ou auditifs liés à la thérapie. Ces initiatives impliquent non seulement une redéfinition locale du déroulement de l’activité institutionnelle et du type de participation « prévue » pour le client à travers les tâches proposées, mais aussi une négociation des catégories identitaires liées à l’activité thérapeutique et de l’asymétrie qu’elles produisent
Singing in "another" language: How pronunciation matters in the organisation of choral rehearsals
No full textIn this paper, I analyse the rehearsals of a choir and focus on sequences during which participants correct and practise the pronunciation of an item. In order to sing in a choir, singers orient both to musical relevancies (such as melody, pitch and rhythm) and to the linguistic features of the words they sing (such as articulation of consonants or vowels, cutting of the syllables, accent): these features are fundamental to singing and can be the object of correction. I hereby take into consideration "second language" singing and show that, during this activity, the correction of a word pronunciation can be initiated and realised either by the director or by the singers themselves. I analyse the structure of these sequences and show their implication for the organisation of the activity and for the participatory dynamics of the rehearsals. Based on the video-recordings of the rehearsals of the choir of a music school, my analyses take into account both the audible and visible resources participants orient to; they thus contribute to a conversation analytical and multimodal perspective on the interactional and institutional activity of music rehearsals. © 2014 © 2014 Taylor & Francis
Coordination, attention visuelle et gestes professionnels dans la rééducation de l’aphasie
No full textDans cette contribution, nous nous focalisons sur des interactions entre personnes aphasiques et orthophonistes au cours des séances de rééducation de la parole. En soulignant la nature interactive et multimodale des activités thérapeutiques, notre étude se penche sur des phénomènes de coordination et d’établissement et négociation de l’attention visuelle. L’analyse porte sur une collection d’extraits dans lesquels le thérapeute sollicite le regard du patient par l’emploi de plusieurs ressources, dont des directifs qui portent sur le regard. Ces sollicitations permettent de guider l’attention visuelle envers certains éléments du contexte et de négocier des configurations participatives adéquates pour profiter des formes d’étayage offertes par le thérapeute et accomplir les tâches de manière collaborative. Nous soulignons la centralité des gestes professionnels et des ressources corporelles mobilisés par le thérapeute et nous analysons la manière dont le patient est « instruit » à voir ces ressources. En reprenant plusieurs aspects de l’œuvre de Goodwin, notre contribution souligne des pratiques interactives et socialement organisées dans lesquelles prend forme l’institution thérapeutique de traitement de l’aphasie
Making Sounds Visible in Speech-Language Therapy for Aphasia
No full textIn this paper, I analyse video recordings of speech-language therapy sessions for people diagnosed with aphasia. I particularly explore the way in which the speech-language therapists instruct the patients to correctly pronounce speech sounds (e.g. phonemes, syllables) by deploying not only audible but also visible forms of cues. By using their bodies – face and gestures – as an instructional tool, the therapists make visual perceptual access to articulatory features of pronunciation relevant and salient. They can also make these sensory practices accountable through the use of other senses, such as touch. Data was collected in a hospital and in a rehabilitation clinic, tracking each patient’s recovery, and is part of a longitudinal multisite corpus. The paper considers the way in which participants in the therapeutic process use and coordinate forms of sensory access to language that are based on hearing and seeing. It highlights the importance of audio and video recordings to make accessible the auditory and visual details of these sensorial experiences – particularly, proper framings and the complementary use of fixed and mobile cameras
Haptics and emotions in speech and language therapy sessions for people with post-stroke aphasia
No full textThis chapter focuses on the role of haptic resources such as touch in the handling of emotions in the institutional setting of a stroke unit, where people diagnosed with aphasia receive, as part of their overall recovery, their first speech and language therapeutic treatment. Patients with post-stroke aphasia can experience frustration, anger and sadness, which can also evolve into crying. As a consequence, interactions between aphasic patients and speech and language therapists working in the hospital can be very emotionally charged. During these moments of distress, touch plays a key role in establishing physical and emotional intimacy, affection and comfort – more broadly, in emotion regulation. Focusing on the interactive use of touch by therapists and patients, as well as on their subtle negotiation of soothing and being soothed, my paper contributes to an embodied perspective on emotions. It emphasizes the central role played by the therapist in emotion regulation, as well as the central caring and relational dimension involved in aphasia speech and language therapy
Assisting the Client in Aphasia Speech Therapy: A Sequential and Multimodal Analysis of Cueing Practices
No full textThis paper investigates aphasia speech therapy as a particular form of institutional interaction dedicated to the recovery of language and communicative abilities in adult speakers. This specific form of social interaction involves both health and pedagogical issues, by presenting features generally observed in instructional settings. The paper investigates these features by focusing on the interactional and sequential organisation of naming activity – that is, the activity of naming a card. Through detailed analyses of participants’ multimodal conduct, it is shown that this task (e.g. producing a specific linguistic item) is collaboratively accomplished. This defends a conception of the therapy as a socially situated and collaborative process, whose dynamics must be investigated taking into consideration participants’ multimodal resources. By focusing in particular on the cueing practices used by the therapist in order to assist the client’s word retrieval and production of the target item, the paper shows that these practices are strictly dependent on the micro-details of interaction, on the client’s audible and visible conduct, and as such are incrementally and locally occasioned. It therefore highlights the active role played by the client in negotiating the assistance needed by the therapist and, more broadly, in co-constructing the therapeutic process
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