483 research outputs found
Alabastro
No full textLa parte di voce redatta da P.F. Pistilli rivolge lo sguardo alla produzione in alabastro fuori dall'Inghilterra, trattando alcuni casi italiani e spagnoli di età romanica e gotica
The acquisition of professional competence.
Get PDFThe research began by examining professions, both historically and as they are today. It went on to investigate the nature of professional practice and professional competence. In particular, it attempted to throw fresh light on how professional competence is acquired and maintained. The research consisted of an extensive literature study and empirical work which included in- depth interviews with practitioners from 20 different professions. This was followed by a series of larger-scale postal surveys across six of these. The chosen professions ranged from traditional ones, including the Church, the Bar and Medicine, to newer professional-type occupations, such as Training, Personnel Management and Information Technology Consultancy. A total of 80 people were interviewed and a further 372 completed survey questionnaires. Following a review of existing models of competence, a new, 'provisional model of professional competence' was developed. This drew on a number of earlier models and related concepts, and was influenced by both reflective practitioner and competence based approaches to professional development. The new model was exposed to expert and academic criticism through a series of conference and journal papers, comments being received from a total of 70 people. The model was also tested empirically, after which a revised version was developed. The empirical stage of the research had a number of strands, in addition to being used for testing the model. It examined the nature of modem professions and tested the validity of certain characteristics traditionally associated with professions - altruism, autonomy, self- regulation, etc. It also examined the nature of professional practice and tested the validity of two competing epistemologies - 'technical-rationality' and 'knowing-in-action' (reflective practice). It investigated how professional competence is acquired, examining the contribution made by both formal development programmes and various kinds of informal experience to which practitioners are exposed. It sought to identify the conditions and environments that are important to professional learning, especially in early practice. Finally, it looked at how professionals maintain their competence through personal learning and continuing professional development (CPD). Both qualitative and quantitative methods were employed throughout. Analysis of results led to the identification of 12 general learning processes or 'learning mechanisms'. These formed the basis of a taxonomy which was used to classify the range of informal learning experiences and events reported by respondents. Outputs from the research included: "a new model of professional competence; "a taxonomy of informal professional learning methods; "a proposed new (or modified) epistemology of professional practice; "a proposed new paradigm of professional development, together with a linked self- development paradigm; an exemplar professional development model; and "a number of practical suggestions for improving professional development programmes. The research has contributed to knowledge by throwing new light on the nature of both professional practice and professional competence, and providing insights into the ways in which people become effective in their professional role
A density functional study of the high-pressure chemistry of MSiN2(M = Be,Mg, Ca)
Get PDFNormal pressure modifications and tentative high-pressure phases of the nitridosilicates MSiN2 with M = Be, Mg, or Ca have been thoroughly studied by density functional methods. At ambient pressure, BeSiN2 and MgSiN2 exhibit an ordered wurtzite variant derived from idealized filled β-cristobalite by a C1-type distortion. At ambient pressure, the structure of CaSiN2 can also be derived from idealized filled β-cristobalite by a different type of distortion (D1-type). Energy–volume calculations for all three compounds reveal transition into an NaCl superstructure under pressure, affording sixfold coordination for Si. At 76 GPa BeSiN2 forms an LiFeO2-type structure, corresponding to the stable ambient-pressure modification of LiFeO2, while MgSiN2 and CaSiN2 adopt an LiFeO2-type structure, corresponding to a metastable modification (24 and 60 GPa, respectively). For both BeSiN2 and CaSiN2 intermediate phases appear (for BeSiN2 a chalcopyrite-type structure and for CaSiN2 a CaGeN2-type structure). These two tetragonal intermediate structures are closely related, differing mainly in their c/a ratio. As a consequence, chalcopyrite-type structures exhibit tetrahedral coordination for both cations (M and Si), whereas in CaGeN2-type structures one cation is tetrahedrally (Si) and one bisdisphenoidally (M) coordinated. Both structure types, chalcopyrite and CaGeN2, can also be derived from idealized filled β-cristobalite through a B1-type distortion. The group–subgroup relation of the BeSiN2/MgSiN2, the CaSiN2, the chalcopyrite, the CaGeN2 and the idealized filled β-cristobalite structure is discussed and the displacive phase transformation pathways are illustrated. The zero-pressure bulk moduli were calculated for all phases and have been found to be comparable to compounds such as α- Si3N4, CaIrO3 and Al4C3. Furthermore, the thermodynamic stability of BeSiN2, MgSiN2 and CaSiN2 against phase agglomerates of the binary nitrides M3N2 and Si3N4 under pressure are examined
Solvothermal chemistry of luminescent lanthanide fluorides
No full textExploration of novel lanthanide fluoride framework materials in inorganic-organic hybrid
systems under solvothermal conditions towards development of new luminescent
materials is discussed. X-ray single crystal and powder diffraction methods have been
used as crystallographic characterisation techniques. Determination and study of
luminescence properties for selected hybrid materials has also been carried out.
The first organically templated luminescent lanthanide fluoride framework, [C₂N₂H₁₀]₀.₅
[Ln₂F₇] (Ln= Nd, Tb, Dy, Ho, Er, Yb and Lu), has been synthesised and characterised.
This structure type consists of a three-dimensional yttrium fluoride framework
incorporating two similar, but crystallographically distinct, yttrium sites.
Photoluminescence studies of [C₂N₂H₁₀]₀.₅ [Y₂F₇]: Ln³⁺ (Ln³⁺ = Gd³⁺, Eu³⁺ and Tb³⁺)
have been explored and characteristic luminescence emissions are reported.
An inorganic-organic hybrid indium fluoride and its scandium fluoride analogue,
[C₄H₁₄N₂][MF₅](M=In and Sc) is reported. The structure consists of infinite trans vertex
sharing (InF₅)[subscript(∞)] chains, which are linked via H-bonded organic moieties. The scandium
and fluorine local environments of [C₄H₁₄N₂][ScF₅] are characterised by ¹⁹F, and
⁴⁵Sc
solid-state MAS NMR spectroscopies. A single scandium site has been confirmed by
⁴⁵Sc
MAS NMR. ¹⁹F MAS NMR clearly differentiates between bridging and terminal
fluorine. The photoluminescence properties of these complexes, [C₄H₁₄N₂][In[subscript(1-x)] Ln[subscript(x)]F₅]
(Ln=Tb and/or Eu), have been explored. The optimum composition for Eu³⁺ doped
samples occurs at x = 0.05 Eu³⁺ and the “asymmetry ratio” of R = I₅₉₀/I₆₁₅ (
⁵D₀ →
⁷F₂ and
⁵D₀ →
⁷F₁) gives a clear picture of the sensitivity for crystal field of the compound.
For x = 0.08 Tb³⁺, a strong down-conversion fluorescence corresponding to
⁵D₄ →
⁷F₅ (green at 543.5 nm) occurs. In addition, a Tb³⁺/Eu³⁺ co-doped sample exhibits a
combination of green (Tb³⁺) and orange (Eu³⁺) luminescence, with Tb³⁺ enhancing the
emission of Eu³⁺ in this host.
Exploration of novel indium, aluminium, and zirconium fluoride crystal structures with
potential luminescent properties has also been undertaken. A chiolite-like phase K₅In₃F₁₄
(space group P4/mnc) has been synthesised. No phase transition occurs over the
temperature range 113K< T< 293 K, as has been seen in other chiolite-like structures. An
organically templated indium fluoride, [NH₄]₃[C₆H₂₁N₄]₂[In₄F₂₁] has been prepared; this
features the trimeric unit [In₃F₁₅]³⁻ which appears to be the first of its type in a metal fluoride. A new hybrid fluoride, Sr[N₂C₂H₁₀]₂[Al₂F₁₂].H₂O has been synthesised.
Because the ionic radius of Eu²⁺ is similar to that of Sr
²⁺ this may be a potential host for
blue luminescent Eu²⁺. The new material KZrF₅.H₂O shows pentagonal-bipyramidal
geometry of Zr⁴⁺ with a polar space group, Pb2₁m, which may potentially have
ferroelectric properties
On the Crystal Structure of Azafullerene (C 59 N) 2
No full textSynchrotron X-ray powder diffraction data of the nitrogen-substituted fullerene solid with stoichiometry C59N point to a monoclinic crystal structure comprising dimeric molecular, (C59N)(2), units
Soft case-based reasoning
No full textAuthor name used in this publication: Simon ShiuVersion of RecordPublishedVoR allowe
Retinitis Pigmentosa GTPase Regulator (RPGR) protein isoforms in mammalian retina:insights into X-linked Retinitis Pigmentosa and associated ciliopathies
Get PDFMutations in the cilia-centrosomal protein Retinitis Pigmentosa GTPase Regulator (RPGR) are a frequent cause of retinal degeneration. The RPGR gene undergoes complex alternative splicing and encodes multiple protein isoforms. To elucidate the function of major RPGR isoforms (RPGR 1-19 and RPGR ORF15), we have generated isoform-specific antibodies and examined their expression and localization in the retina. Using sucrose-gradient centrifugation, immunofluorescence and co-immunoprecipitation methods, we show that RPGR isoforms localize to distinct sub-cellular compartments in mammalian photoreceptors and associate with a number of cilia-centrosomal proteins. The RCC1-like domain of RPGR, which is present in all major RPGR isoforms, is sufficient to target it to the cilia and centrosomes in cultured cells. Our findings indicate that multiple isotypes of RPGR may perform overlapping yet somewhat distinct transport-related functions in photoreceptors
Determining knot groups by finite quotients
Get PDFWe prove that hyperbolic 2-bridge knots are determined amongst all compact 3-manifolds by the profinite completions of their knot groups.The authors wish to withdraw this article. The attempted proof of Theorem 1.1 is incorrect because of its dependence on the statement of Theorem 2.2 in this article. The first author\u27s attempted proof of Theorem 2.2 (arXiv:2308.00266v2) is incorrec
WebCARMA: a web application for the functional and taxonomic classification of unassembled metagenomic reads
Get PDFGerlach W, Jünemann S, Tille F, Goesmann A, Stoye J. WebCARMA: a web application for the functional and taxonomic classification of unassembled metagenomic reads. BMC Bioinformatics. 2009;10(1):430.Background Metagenomics is a new field of research on natural microbial communities. High-throughput sequencing techniques like 454 or Solexa-Illumina promise new possibilities as they are able to produce huge amounts of data in much shorter time and with less efforts and costs than the traditional Sanger technique. But the data produced comes in even shorter reads (35-100 basepairs with Illumina, 100-500 basepairs with 454-sequencing). CARMA is a new software pipeline for the characterisation of species composition and the genetic potential of microbial samples using short, unassembled reads. Results In this paper, we introduce WebCARMA, a refined version of CARMA available as a web application for the taxonomic and functional classification of unassembled (ultra-)short reads from metagenomic communities. In addition, we have analysed the applicability of ultra-short reads in metagenomics. Conclusions We show that unassembled reads as short as 35 bp can be used for the taxonomic classification of a metagenome. The web application is freely available at http://webcarma.cebitec.uni-bielefeld.d
Colatooecia serrulata
No full textColatooecia serrulata (Smitt, 1873) (Fig. 2, Table 1) Porina serrulata Smitt, 1873: 27, pl. 5, figs 116–125. [W of Tortugas and Florida] Cigclisula serrulata: Canu & Bassler 1928a: 125, pl. 20, figs 1–14, text-fig. 24. [Fowey Light, Miami, Florida] Spiroporina ? serrulata: Cheetham & Sandberg 1964: 1027, text-figs 26–27. [Gulf of Mexico] Colatooecia serrulata: Winston 2005: 93, figs 257–261. [W of Tortugas and Florida] Material examined. USNM 7476, Cigclisula serrulata, F. Canu & R.S. Bassler det., 1928a, Fowey Light, 15 miles (24.1 km) South of Miami, Florida. Description. Colony erect, bilaminar, branching. Zooids hexagonal at growing edge, becoming irregular with development, longer than wide, limited by slightly raised walls. Frontal shield heavily calcified, with 22–36 regularly spaced pseudopores. Primary orifice small relative to frontal shield, almost rounded, wider than long, lacking condyles. Secondary orifice subcircular, with smooth peristome that becomes embedded in frontal surface with colony development. Often 1, rarely 2, rounded adventitious avicularia placed at zooidal margins near primary orifice and sometimes at proximal border of ectooecium. Frontal avicularia with large rostrum, rectangular, longer than wide, with rounded proximal and straight distal edge; calcified palate occupies half rostral length; opesia trifoliate proximally, quadrangular distally. Interzooidal avicularia placed at margins of colony, as long as zooids, rostrum straight, spatulate, longer than wide, proximal edge rounded and distal edge deep, concave; calcified palate occupies more than half rostral length, its foramen somewhat trifoliate owing to a ligula; avicularian opesia smaller, quadrangular. Ooecium immersed; ectooecium with central membranous area; entooecium bridged by sieve of delicate costae that interdigitate at mid-point of ooecium. Remarks. Colatooecia is monotypic. The type species Colatooecia serrulata was previously included in Porina (Smitt 1873), Cigclisula (Canu & Bassler 1928) and, doubtfully, Spiroporina (Cheetham & Sandberg 1964) (see Winston 2005). Cheetham & Sandberg (1964) pointed out that the species could not be placed easily in any known genus; Winston (2005) introduced Colatooecia for it based on the appearance of the frontal calcification and the distinctive costate ooecium. The combination of a spiramen, thick porous frontal calcification, ectooecium with an elongate membranous area, two rows of tiny entooecial costae and rectangular frontal avicularia with distal trifoliate and proximal quadrate openings in C. serrulata is unique in the family. Distribution. Northwestern Atlantic: Cape Hatteras to Florida and Gulf of Mexico (Winston 2005).Published as part of Almeida, Ana C. S., Souza, Facelucia B. C., Menegola, Carla M. S., Sanner, Joann & Vieira, Leandro M., 2014, Taxonomic review of the family Colatooeciidae Winston, 2005 (Bryozoa, Cheilostomata), with description of seven new species, pp. 1-61 in Zootaxa 3868 (1) on page 6, DOI: 10.11646/zootaxa.3868.1.1, http://zenodo.org/record/493065
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