3,490 research outputs found

    The role of affect and cognitive schemata in the assessment of psychopathy

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    This thesis examined psychopathy, cognitive schemata and affect in forensic and community populations. This was to identify whether cognitive schemata and affect would assist in the assessment of psychopathy. Study one was conducted on 38 male high secure hospital patients and 38 male prisoners. It focused on the assessment of psychopathy and cognitive schemata. It was predicted that psychopathy would be positively related to negative schemata and early maladaptive schemata and negatively related to positive schemata. This prediction was supported with the exception of Early Maladaptive Schemata. Study two was conducted on 38 male high secure hospital patients and 38 male prisoners and also examined psychopathy and affect. It further explored positive schemata that was significant in study one. It was predicted that psychopathy would be positively related to errors on affective word sentence completion with slower response times. These predictions were not supported. The third study included 101 male prisoners and 108 male university students. An assessment of cognitive schema and affect was also developed. A further core prediction was that psychopathy would have a positive relationship with detached affect and results supported this. Contrary to prediction, it was found that psychopathy was higher in the student group compared to the prisoner group. Study four further explored the core predictions and included an examination of psychopathy, cognitive schema, affect and the 'Big Five' in 174 prisoners and 200 male students. The predictions were supported that psychopathy would be negatively related to positive cognitive schemata and positively related to negative cognitive schemata, in both groups. The predictions that detached affect would be significant to psychopathy was again supported. Contrary to prediction psychopathy was found to be higher in the student group. The current research indicates that cognitive schemata and affect are related to psychopathy. It also shows that similar cognitive profiles of psychopathy are demonstrated in prison and student groups that relate to affect. Further, it highlights the neglected role of positive schemata in psychopathy. Future research could consider the role of positive schemata and refine the cognitive profile in psychopathy, it could also examine the newly proposed cognitive behavioural model of psychopathy

    Evaluating two methods for Treebank grammar compaction

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    Treebanks, such as the Penn Treebank, provide a basis for the automatic creation of broad coverage grammars. In the simplest case, rules can simply be ‘read off’ the parse-annotations of the corpus, producing either a simple or probabilistic context-free grammar. Such grammars, however, can be very large, presenting problems for the subsequent computational costs of parsing under the grammar. In this paper, we explore ways by which a treebank grammar can be reduced in size or ‘compacted’, which involve the use of two kinds of technique: (i) thresholding of rules by their number of occurrences; and (ii) a method of rule-parsing, which has both probabilistic and non-probabilistic variants. Our results show that by a combined use of these two techniques, a probabilistic context-free grammar can be reduced in size by 62% without any loss in parsing performance, and by 71% to give a gain in recall, but some loss in precision

    Mass flow through solid 4He induced by the fountain effect

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    Using an apparatus that allows superfluid liquid 4He to be in contact with hcp solid \4he at pressures greater than the bulk melting pressure of the solid, we have performed experiments that show evidence for 4He mass flux through the solid and the likely presence of superfluid inside the solid. We present results that show that a thermomechanical equilibrium in quantitative agreement with the fountain effect exists between two liquid reservoirs connected to each other through two superfluid-filled Vycor rods in series with a chamber filled with solid 4He. We use the thermomechanical effect to induce flow through the solid and measure the flow rate. On cooling, mass flux appears near T = 600 mK and rises smoothly as the temperature is lowered. Near T = 75 mK a sharp drop in the flux is present. The flux increases as the temperature is reduced below 75 mK. We comment on possible causes of this flux minimum.Comment: 20 pages, 22 figures, 7 table

    Cell and gene therapy in Australia

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    The expansion of human cells to produce cell therapeutic products for the treatment of disease is, with few exceptions, an experimental therapy. Because cell therapies involve a biological product, often with some genetic or other modification, they require extensive pre-clinical research and development. Cell therapy production processes and premises require licensing by the Therapeutic Goods Administration. In this review, timed to coincide with the international meetings of the ISCT and ISSCR in Australia, we describe some promising cell therapies currently under development

    Synthesis of DNA-polymer conjugates using RAFT polymerisation

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    The use of reversible addition–fragmentation chain transfer (RAFT) polymerisation for the production of DNA–polymer conjugates is explored. Chapter 1 gives a general introduction to the field of DNA–polymer conjugates, their potential applications and methods for their synthesis. The need for a general, solutionphase technique for DNA–polymer conjugation is highlighted. In Chapters 2-5, the use of a number of different strategies for the production of DNA–polymer conjugates is described. Amide coupling (Chapter 2) is found to produce the desired products only under very specific reaction conditions. The thiol–alkene Michael addition reaction (Chapter 3) is found to afford DNA–polymer conjugates in aqueous solution with high yield; however, attempts to replicate this using organic solvents are not successful. The inverse electron-demand Diels–Alder reaction between tetrazine and norbornene (Chapter 4) is explored and found to produce DNA–polymer conjugates in high yield in organic solvents; however, the precursor compounds are time-consuming to prepare and so the generality of this approach is limited. Finally, the copper-catalysed azide–alkyne cycloaddition (Chapter 5) is found to be an excellent method for the production of a wide range of DNA–polymer conjugates. Chapter 6 describes the use of the DNA segment of a DNA–polymer conjugate to assemble a discrete three dimensional nanostructure – a DNA tetrahedron – incorporating the temperature-responsive polymer poly(N-isopropylacrylamide). These hybrid structures are found to be able to stabilise the formation of discrete, well-defined polymer nanoparticles at elevated temperatures. Chapter 7 describes the use of a non-covalent interaction (intercalation) to produce DNA– polymer conjugates. The effect of polymer molecular weight and structure on the strength of this interaction are explored. Finally, intercalation is exploited to template the formation of discrete polymer particles on a DNA strand

    Apollonian Circle Packings: Geometry and Group Theory II. Super-Apollonian Group and Integral Packings

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    Apollonian circle packings arise by repeatedly filling the interstices between four mutually tangent circles with further tangent circles. Such packings can be described in terms of the Descartes configurations they contain. It observed there exist infinitely many types of integral Apollonian packings in which all circles had integer curvatures, with the integral structure being related to the integral nature of the Apollonian group. Here we consider the action of a larger discrete group, the super-Apollonian group, also having an integral structure, whose orbits describe the Descartes quadruples of a geometric object we call a super-packing. The circles in a super-packing never cross each other but are nested to an arbitrary depth. Certain Apollonian packings and super-packings are strongly integral in the sense that the curvatures of all circles are integral and the curvature×\timescenters of all circles are integral. We show that (up to scale) there are exactly 8 different (geometric) strongly integral super-packings, and that each contains a copy of every integral Apollonian circle packing (also up to scale). We show that the super-Apollonian group has finite volume in the group of all automorphisms of the parameter space of Descartes configurations, which is isomorphic to the Lorentz group O(3,1)O(3, 1).Comment: 37 Pages, 11 figures. The second in a series on Apollonian circle packings beginning with math.MG/0010298. Extensively revised in June, 2004. More integral properties are discussed. More revision in July, 2004: interchange sections 7 and 8, revised sections 1 and 2 to match, and added matrix formulations for super-Apollonian group and its Lorentz version. Slight revision in March 10, 200

    Apollonian Circle Packings: Geometry and Group Theory III. Higher Dimensions

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    This paper gives nn-dimensional analogues of the Apollonian circle packings in parts I and II. We work in the space \sM_{\dd}^n of all nn-dimensional oriented Descartes configurations parametrized in a coordinate system, ACC-coordinates, as those (n+2)×(n+2)(n+2) \times (n+2) real matrices \bW with \bW^T \bQ_{D,n} \bW = \bQ_{W,n} where QD,n=x12+...+xn+22−1n(x1+...+xn+2)2Q_{D,n} = x_1^2 +... + x_{n+2}^2 - \frac{1}{n}(x_1 +... + x_{n+2})^2 is the nn-dimensional Descartes quadratic form, QW,n=−8x1x2+2x32+...+2xn+22Q_{W,n} = -8x_1x_2 + 2x_3^2 + ... + 2x_{n+2}^2, and \bQ_{D,n} and \bQ_{W,n} are their corresponding symmetric matrices. There are natural actions on the parameter space \sM_{\dd}^n. We introduce nn-dimensional analogues of the Apollonian group, the dual Apollonian group and the super-Apollonian group. These are finitely generated groups with the following integrality properties: the dual Apollonian group consists of integral matrices in all dimensions, while the other two consist of rational matrices, with denominators having prime divisors drawn from a finite set SS depending on the dimension. We show that the the Apollonian group and the dual Apollonian group are finitely presented, and are Coxeter groups. We define an Apollonian cluster ensemble to be any orbit under the Apollonian group, with similar notions for the other two groups. We determine in which dimensions one can find rational Apollonian cluster ensembles (all curvatures rational) and strongly rational Apollonian sphere ensembles (all ACC-coordinates rational).Comment: 37 pages. The third in a series on Apollonian circle packings beginning with math.MG/0010298. Revised and extended. Added: Apollonian groups and Apollonian Cluster Ensembles (Section 4),and Presentation for n-dimensional Apollonian Group (Section 5). Slight revision on March 10, 200

    Apollonian Circle Packings: Geometry and Group Theory I. The Apollonian Group

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    Apollonian circle packings arise by repeatedly filling the interstices between four mutually tangent circles with further tangent circles. We observe that there exist Apollonian packings which have strong integrality properties, in which all circles in the packing have integer curvatures and rational centers such that (curvature)×\times(center) is an integer vector. This series of papers explain such properties. A {\em Descartes configuration} is a set of four mutually tangent circles with disjoint interiors. We describe the space of all Descartes configurations using a coordinate system \sM_\DD consisting of those 4×44 \times 4 real matrices \bW with \bW^T \bQ_{D} \bW = \bQ_{W} where \bQ_D is the matrix of the Descartes quadratic form QD=x12+x22+x32+x42−1/2(x1+x2+x3+x4)2Q_D= x_1^2 + x_2^2+ x_3^2 + x_4^2 -{1/2}(x_1 +x_2 +x_3 + x_4)^2 and \bQ_W of the quadratic form QW=−8x1x2+2x32+2x42Q_W = -8x_1x_2 + 2x_3^2 + 2x_4^2. There are natural group actions on the parameter space \sM_\DD. We observe that the Descartes configurations in each Apollonian packing form an orbit under a certain finitely generated discrete group, the {\em Apollonian group}. This group consists of 4×44 \times 4 integer matrices, and its integrality properties lead to the integrality properties observed in some Apollonian circle packings. We introduce two more related finitely generated groups, the dual Apollonian group and the super-Apollonian group, which have nice geometrically interpretations. We show these groups are hyperbolic Coxeter groups.Comment: 42 pages, 11 figures. Extensively revised version on June 14, 2004. Revised Appendix B and a few changes on July, 2004. Slight revision on March 10, 200

    High-resolution thermal expansion measurements under Helium-gas pressure

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    We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K ≤T≤\leq T \leq 300 K and hydrostatic pressure P≤P \leq 250 MPa. Helium (4^4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P≃P \simeq 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu3_3(CO3_3)2_2(OH)2_2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.Comment: 8 pages, 7 figures, published in Rev. Sci. Instrum with minor change
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