269 resultados para Symmetric Group
Raman spectroscopic study of a hydroxy-arsenate mineral containing bismuth-atelestite Bi2O(OH)(AsO4)
Resumo:
The Raman spectrum of atelestite Bi2O(OH)(AsO4), a hydroxy-arsenate mineral containing bismuth, has been studied in terms of spectra-structure relations. The studied spectrum is compared with the Raman spectrum of atelestite downloaded from the RRUFF database. The sharp intense band at 834 cm-1 is assigned to the 1 AsO43- (A1) symmetric stretching mode and the three bands at 767, 782 and 802 cm-1 to the 3 AsO43- antisymmetric stretching modes. The bands at 310, 324, 353, 370, 395, 450, 480 and 623 cm-1 are assigned to the corresponding ν4 and ν2 bending modes and Bi-O-Bi (vibration of bridging oxygen) and Bi-O (vibration of non-bridging oxygen) stretching vibrations. Lattice modes are observed at 172, 199 and 218 cm-1. A broad low intensity band at 3095 cm-1 is attributed to the hydrogen bonded OH units in the atelestite structure. A weak band at 1082 cm-1 is assigned to (Bi-OH) vibration.
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The idealised theory for the quasi-static flow of granular materials which satisfy the Coulomb-Mohr hypothesis is considered. This theory arises in the limit that the angle of internal friction approaches $\pi/2$, and accordingly these materials may be referred to as being `highly frictional'. In this limit, the stress field for both two-dimensional and axially symmetric flows may be formulated in terms of a single nonlinear second order partial differential equation for the stress angle. To obtain an accompanying velocity field, a flow rule must be employed. Assuming the non-dilatant double-shearing flow rule, a further partial differential equation may be derived in each case, this time for the streamfunction. Using Lie symmetry methods, a complete set of group-invariant solutions is derived for both systems, and through this process new exact solutions are constructed. Only a limited number of exact solutions for gravity driven granular flows are known, so these results are potentially important in many practical applications. The problem of mass flow through a two-dimensional wedge hopper is examined as an illustration.
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The Airy stress function, although frequently employed in classical linear elasticity, does not receive similar usage for granular media problems. For plane strain quasi-static deformations of a cohesionless Coulomb–Mohr granular solid, a single nonlinear partial differential equation is formulated for the Airy stress function by combining the equilibrium equations with the yield condition. This has certain advantages from the usual approach, in which two stress invariants and a stress angle are introduced, and a system of two partial differential equations is needed to describe the flow. In the present study, the symmetry analysis of differential equations is utilised for our single partial differential equation, and by computing an optimal system of one-dimensional Lie algebras, a complete set of group-invariant solutions is derived. By this it is meant that any group-invariant solution of the governing partial differential equation (provided it can be derived via the classical symmetries method) may be obtained as a member of this set by a suitable group transformation. For general values of the parameters (angle of internal friction and gravity g) it is found there are three distinct classes of solutions which correspond to granular flows considered previously in the literature. For the two limiting cases of high angle of internal friction and zero gravity, the governing partial differential equation admit larger families of Lie point symmetries, and from these symmetries, further solutions are derived, many of which are new. Furthermore, the majority of these solutions are exact, which is rare for granular flow, especially in the case of gravity driven flows.
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Raman spectrum of burgessite, Co2(H2O)4[AsO3OH]2.H2O was studied, interpreted and compared with its infrared spectrum. The stretching and bending vibrations of (AsO3) and As-OH units together with the stretching, bending and libration modes of water molecules and hydroxyl ions were assigned. The range of O-H...O hydrogen bond lengths was inferred from the Raman and infrared spectra of burgessite. The presence of (AsO3OH)2- units in the crystal structure of burgessite was proved in agreement with its recently solved crystal structure. Raman and infrared spectra of erythrite inferred from the RRUFF database are used for comparison.
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Background The relationship between positive parent-child interactions and optimal child development is well established. Families with a child with a disability may face additional challenges to establishing positive parent-child relationships. There are limited studies addressing the effectiveness of interventions which seek to address these issues with parents and young children with a disability. In particular, prior studies of music therapy with this group have been limited by small sample sizes and the use of measures of limited reliability and validity. Objective This study investigates the effectiveness of a short-term group music therapy intervention for parents who have a child with a disability and explores the factors associated with higher outcomes for participating families. Methods The participants were 201 mother-child dyads, where the child had a disability. Pre and post intervention parental questionnaires and clinician observation measures were taken on a range of parental wellbeing, parenting behaviours and child developmental factors. Descriptive data, t-tests for repeated measures and a predictive model tested via logistic regression are presented. Results Significant improvements pre to post were found for parent mental health, child communication and social skills, parenting sensitivity, parental engagement with child and acceptance of child, child responsiveness to parent, and child interest and participation in program activities. There was also evidence that parents were very satisfied with the program and that it brought social benefits to families. Reliable change on six or more indicators of parent or child functioning was predicted by attendance and parent education. Conclusions This study provides positive evidence for the effectiveness of group music therapy in promoting improved parental mental health, positive parenting and key child developmental areas. Whilst several limitations are discussed, the study does address some of the gaps in the music therapy evidence base in this area.
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Raman spectra of two well-defined types of koritnigite crystals from the Jáchymov ore district, Czech Republic, were recorded and interpreted. No substantial differences were observed between both crystal types. Observed Raman bands were attributed to the (AsO3OH)2- stretching and bending vibrations, stretching and bending vibrations of water molecules and hydroxyl ions. Non-interpreted Raman spectra of koritnigite from the RRUFF database, and published infrared spectra of cobaltkoritnigite were used for comparison. The O-H...O hydrogen bond lengths in the crystal structure of koritnigite were inferred from the Raman spectra and compared with those derived from the X-ray single crystal refinement. The presence of (AsO3OH)2- units in the crystal structure of koritnigite was proved from the Raman spectra which supports the conclusions of the X-ray structure analysis.
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Undergraduates working in teams can be a problematic endeavour, sometimes exacerbated for the student by poor prior experiences, a predisposition to an individual orientation of assessment, and simply the busyness that now typifies the life of a student. But effort in pedagogical design is worthwhile where team work is often a prerequisite in terms of graduate capabilities, robust learning, increased motivation, and indeed in terms of equipping individuals for emergent knowledge-age work practice, often epitomised by collaborative effort in both blended and virtual contexts. Through an iterative approach, based extensively on the established literature, we have developed a successful scaffold which is workable with a large cohort group (n >800), such that it affords students the lived experience of being a part of a learning network. Individuals within teams work together, to develop individual components that are subsequently aggregated and reified to an overall team knowledge artefact. We describe our case and propose a pedagogical model of scaffolding based on three perspectives: conceptual, rule-based and community-driven. This model provides designers with guidelines for producing and refining assessment tasks for team-based learning.
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This audio magazine, written by Melissa Giles, features three Brisbane-based media organisations: Radio 4RPH, Queensland Pride and 98.9FM. [#1 - INTRODUCTION - read by Sara Cowling]----- [#2 - RADIO 4RPH: SHARING THE WORD - read by Ellen-Maree Elliot (and Sara Cowling)]----- [#3 - QUEENSLAND PRIDE: OUT IN THE STREET - read by Dominique Wiehahn (and Sara Cowling)]----- [#4 - 98.9FM: BREAKING THE MOULD - read by Paige Ross (and Sara Cowling)]----- [#5 - CONCLUSION - read by Sara Cowling]
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Anxiety disorders have been viewed as manifestations of broad underlying predisposing personality constructs such as neuroticism combined with more specific individual differences of unhelpful information processing styles. Given the high prevalence of anxiety and the significant impairment that it causes, there is an important need to continue to explore successful treatments for this disorder. Research indicates that there is still room for significantly improving attrition rates and treatment adherence. Traditionally Motivational Interviewing (MI) has been used to facilitate health behaviour change. Recently MI has been applied to psychotherapy and has been shown to improve the outcome of CBT. However, these studies have been limited to only considering pre- and post-treatment measures and neglected to consider when changes occur along the course of therapy. This leaves the unanswered question of what is the impact of pre-treatment MI on the treatment trajectory of therapy. This study provides preliminary research into answering this question by tracking changes on a weekly basis along the course of group CBT. Prior to group CBT, 40 individuals with a principal anxiety disorder diagnosis were randomly assigned to receive either 3 individual sessions of MI or placed on a waitlist control group. All participants then received the same dosage of 10 weekly 2 hour sessions of group CBT. Tracking treatment outcome trajectory over the course of CBT, the pre-treatment MI group, compared to the control group, experienced a greater improvement early on in the course of therapy in their symptom distress, interpersonal relationships and quality of life. This early advantage over the control group was then maintained throughout therapy. These results not only demonstrate the value of adding MI to CBT, but also highlight the immediacy of MI effects. Further research is needed to determine the robustness of these effects to inform clinical implications of how to best apply MI to improve treatment adherence to CBT for anxiety disorders.
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Raman microscopy of two mixite minerals BiCu6(AsO4)3(OH)6.3H2O from Jáchymov and from Smrkovec (both Czech Republic) has been used to study their molecular structure, which is interpreted and the presence of (AsO4)3-, (AsO3OH)2-, (PO4)3- and (PO3OH)2- units, molecular water and hydroxyl ions were inferred. O-H…O hydrogen bond lengths were calculated from the Raman and infrared spectra using Libowitzky’s empirical relation. Small differences in the Raman spectra between both samples were observed and attributed to compositional and hydrogen bonding network differences.
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This paper presents a regional commentary (hereafter ‘the commentary’) on the three Australian projects of the Teasdale-Corti Global Health Research Partnership Program. The three Australian projects are: Victorian Aboriginal Health Service Ltd (VAHS), Melbourne, Victoria—Forty Years of Comprehensive Primary Health Care; Central Australian Aboriginal Congress Inc. (Congress), Alice Springs, Northern Territory—Ingkintja, Male Health Program; and Urapuntja Health Service (UHS), Utopia, Northern Territory—Outstation Health Care. It highlights common themes and lessons in respect to the Revitalising Health for All project in the context of Aboriginal and Torres Strait Islander health in Australia.
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Small element spacing in compact arrays results in strong mutual coupling between array elements. Performance degradation associated with the strong coupling can be avoided through the introduction of a decoupling network consisting of interconnected reactive elements. We present a systematic design procedure for decoupling networks of symmetrical arrays with more than three elements and characterized by circulant scattering parameter matrices. The elements of the decoupling network are obtained through repeated decoupling of the characteristic eigenmodes of the array, which allows the calculation of element values using closed-form expressions.
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This magazine, written by Melissa Giles, features three Brisbane-based media organisations: Radio 4RPH, Queensland Pride and 98.9FM. The PDF file on this website contains a text-only version of the magazine. Contact the author if you would like a copy of the text-only EPUB file or a copy of the full digital magazine with images. An audio version of the magazine is available at http://eprints.qut.edu.au/41729/
Resumo:
Reduced element spacing in antenna arrays gives rise to strong mutual coupling between array elements and may cause significant performance degradation. These effects can be alleviated by introducing a decoupling network consisting of interconnected reactive elements. The existing design approach for the synthesis of a decoupling network for circulant symmetric arrays allows calculation of element values using closed-form expressions, but the resulting circuit configuration requires multilayer technology for implementation. In this paper, a new structure for the decoupling of circulant symmetric arrays of more than four elements is presented. Element values are no longer obtained in closed form, but the resulting circuit is much simpler and can be implemented on a single layer.