1,062 research outputs found

    Class, resistance, and the psychologization of development in South Africa

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    This paper focuses on the psychologization of development in South Africa, one of the most unequal countries in the world, through a critical analysis of a discussion on a national radio programme about the meaning of Mandela Day. We demonstrate how speakers draw on common sense notions of race, class, and party politics that (re)produce subject positions from within a rights-based interpretive repertoire that emphasizes structural reform and class resistance, and an agency interpretive repertoire that emphasizes individualism, responsibility, and volunteerism. We further demonstrate how the agency subject position serves to stifle and resist the rights subject position by drawing on common sense 'psychological truths' about what it means to be a good citizen

    Edge excitations and Topological orders in rotating Bose gases

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    The edge excitations and related topological orders of correlated states of a fast rotating Bose gas are studied. Using exact diagonalization of small systems, we compute the energies and number of edge excitations, as well as the boson occupancy near the edge for various states. The chiral Luttinger-liquid theory of Wen is found to be a good description of the edges of the bosonic Laughlin and other states identified as members of the principal Jain sequence for bosons. However, we find that in a harmonic trap the edge of the state identified as the Moore-Read (Pfaffian) state shows a number of anomalies. An experimental way of detecting these correlated states is also discussed.Comment: Results extended to larger systems. Improved presentatio

    Three-body correlations and finite-size effects in the Moore--Read states on a sphere

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    Two- and three-body correlations in partially filled degenerate fermion shells are studied numerically for various interactions between the particles. Three distinct correlation regimes are defined, depending on the short-range behavior of the pair pseudopotential. For pseudopotentials similar to those of electrons in the first excited Landau level, correlations at half-filling have a simple three-body form consisting of the maximum avoidance of the triplet state with the smallest relative angular momentum R_3=3. In analogy to the superharmonic criterion for Laughlin two-body correlations, their occurrence is related to the form of the three-body pseudopotential at short range. The spectra of a model three-body repulsion are calculated, and the zero-energy Moore--Read ground state, its +-e/4-charged quasiparticles, and the magnetoroton and pair-breaking bands are all identified. The quasiparticles are correctly described by a composite fermion model appropriate for Halperin's p-type pairing with Laughlin correlations between the pairs. However, the Moore--Read ground state, and specially its excitations, have small overlaps with the corresponding Coulomb eigenstates when calculated on a sphere. The reason lies in surface curvature which affects the form of pair pseudopotential for which the "R_3>3" three-body correlations occur. In finite systems, such pseudopotential must be slightly superharmonic at short range (different from Coulomb pseudopotential). However, the connection with the three-body pseudopotential is less size-dependent, suggesting that the Moore--Read state and its excitations are a more accurate description for experimental nu=5/2 states than could be expected from previous calculations.Comment: 12 pages, 12 figures, submitted to PR

    RELIABILITY OF THE BICAUDATE PARAMETER IN THE REVEALING OF THE ENLARGED LATERAL VENTRICLES IN SCHIZOPHRENIA PATIENTS

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    Introduction: In schizophrenia patients the lateral ventricle enlargement has mostly been reported in relationship with smaller cortical and/or subcortical brain volumes; and it has been observed that ventricular system growth may be a consequence of the smaller caudate nucleus volume. Bicaudate parameters have been used in the Alzheimer dementia and Huntington’s chorea diagnosing in order to evaluate brain changes and the enlargement of the lateral ventricles. Subjects and methods: This study has been carried out on 140 patients out of which 70 patients (30 men and 40 women) who met the ICD 10 criteria for schizophrenia and 70 healthy controls (30 men and 40 women) matched on sex and age with the studied group. All of them underwent direct caudatometry and volume computation based on MRI scans. Results: Except for the bicorporal line, for all the parameters were obtained the statistically highly significant differences between the examined and control groups. Significant correlation was established for the majority of bicaudate parameters and volumes of the caudate nuclei and lateral ventricles. Discussion: Enlargement of the lateral ventricles is one of the most frequent MRI finding in schizophrenia patients. Ventricles are enlarging gradually and frontal horns are more affected than other parts. The increased volumes of the caudate nuclei signalized that ventricular enlargement is not the consequence of the caudate atrophy. Conclusion: Bicaudate parameters are reliable parameters for the quick orientation in order to assess the enlarged ventricles in schizophrenia patients

    Study of the Influence of Zeolite and Lignin Type on the Lignin Pyrolysis Products

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    COST Action FP1306: “Valorisation of lignocellulosic biomass side streams for sustainable production of chemicals, materials & fuels using low environmental impact technologies” (LIGNOVAL)published_or_final_versio

    An investigation of using various diesel-type fuels in homogeneous charge compression ignition engines and their effects on operational and controlling issues

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    Homogeneous charge compression ignition (HCCI) engines appear to be a future alternative to diesel and spark-ignited engines. The HCCI engine has the potential to deliver high efficiency and very low NOx and particulate matter emissions. There are, however, problems with the control of ignition and heat release range over the entire load and speed range which limits the practical application of this technology. The aim of this paper is to analyse the use of different types of diesel fuels in an HCCI engine and hence to find the most suitable with respect to operational and control issues. The single-zone combustion model with convective heat transfer loss is used to simulate the HCCI engine environment. n-Heptane, dimethyl ether and bio-diesel (methyl butanoate and methyl formate) fuels are investigated. Methyl butanoate and methyl formate represent surrogates of heavy and light bio-diesel fuel respectively. The effects of different engine parameters such as equivalence ratio and engine speed on the ignition timing are investigated. The use of internal exhaust gas recirculation is investigated as a potential strategy for controlling the ignition timing. The results indicate that the use of bio-diesel fuels will result in lower sensitivity of ignition timing to changes in operational parameters and in a better control of the ignition process when compared with the use of n-heptane and dimethyl ether

    Annealed disorder, rare regions, and local moments: A novel mechanism for metal-insulator transitions

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    Local magnetic moments in disordered sytems can be described in terms of annealed magnetic disorder, in addition to the underlying quenched disorder. It is shown that for noninteracting electron systems at zero temperature, the annealed disorder leads to a new mechanism, and a new universality class, for a metal-insulator transition. The transition is driven by a vanishing of the thermodynamic density susceptibility rather than by localization effects. The critical behavior near two-dimensions is determined, and the underlying physics is discussed.Comment: 4 pp., LaTeX, no figs., final version as publishe

    Point-like topological defects in bilayer quantum Hall systems

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    Following a suggestion given in Phys. Lett. B 571 (2003) 250, we show how a bilayer Quantum Hall system at fillings nu =m/pm+2 can exhibit a point-like topological defect in its edge state structure. Indeed our CFT theory for such a system, the Twisted Model (TM), gives rise in a natural way to such a feature in the twisted sector. Our results are in agreement with recent experimental findings (cond-mat/0503478) which evidence the presence of a topological defect in the bilayer system.Comment: 9 pages, 3 figure

    Color measurement of animal source foods

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    Rapid and objective assessment of food color is necessary in quality control. The color evaluation of animal source foods using a computer vision system (CVS) and a traditional colorimeter is examined. With the same measurement conditions, color results deviated between these two approaches. The color returned by the CVS had a close resemblance to the perceived color of the animal source foods, whereas the colorimeter returned not typical colors. The effectiveness of the CVS is confirmed by the study results. Considering these data, it could be concluded that the colorimeter is not representative method for color analysis of animal source foods, therefore, the color read by the CVS seemed to be more similar to the real ones
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