1,114 research outputs found

    Twenty years of punishment (and democracy) in South Africa: The pitfalls of governing crime through the community

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    This article examines how the ideology of ‘community’ is deployed to  govern crime in South Africa, both by marginalised black communities and by the government. Although the turn to ‘community’ started under theNational Party government in the late 1970s, there is no doubt that as a site, technology, discourse, ideology and form of governance, ‘community’ has become entrenched in the post-1994 era. Utilising empirical data drawn from ethnographic research on vigilantism in Khayelitsha, as well as archival materials in respect of ANC policies and practices before it became the governing party, I argue that rallying ‘communities’ around crime combatting has the potential to unleash violent technologies in the quest for ‘ethics’ and ‘morality’. When community members unite against an outsider they are bonded for an intense moment in a way that masks thevery real problems that tear the community apart. Because violent  punishment is one of the consequences of the state’s turn towards   democratic localism, we should question the way in which the ‘community’ is deployed as a tool of crime prevention, and subject it to rigorous scrutin

    Constructing Dirac linear fermions in terms of non-linear Heisenberg spinors

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    We show that the massive (or massless) neutrinos can be described as special states of Heisenberg nonlinear spinors. As a by-product of this decomposition a particularly attractive consequence appears: the possibility of relating the existence of only three species of mass-less neutrinos to such internal non-linear structure. At the same time it allows the possibility that neutrino oscillation can occurs even for massless neutrinos

    Symmetries, Large Leptonic Mixing and a Fourth Generation

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    We show that large leptonic mixing occurs most naturally in the framework of the Sandard Model just by adding a fourth generation. One can then construct a small Z4Z_4 discrete symmetry, instead of the large S4L×S4RS_{4L}\times S_{4R}, which requires that the neutrino as well as the charged lepton mass matrices be proportional to a 4×44\times 4 democratic mass matrix, where all entries are equal to unity. Without considering the see-saw mechanism, or other more elaborate extensions of the SM, and contrary to the case with only 3 generations, large leptonic mixing is obtained when the symmetry is broken.Comment: 6 pages, ReVTeX, no figure

    A robust subspace based approach to feedforward control of broadband disturbances on a six-degrees-of-freedom vibration isolation set-up

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    The contribution of this paper is twofold. First, the paper introduces a novel hybrid vibration isolation approach which uses a combination of passive and active vibration control techniques to provide additional design freedom. The approach can be used to meet higher design requirements with respect to vibration isolation. To illustrate the feasibility of the approach, a stiff hybrid sixdegrees-of-freedom vibration isolation set-up will be presented. The objective of the set-up is to investigate if the receiver structure can be isolated from the source structure by six hybrid vibration isolation mounts, such that disturbances induced by the source structure are isolated from the receiver structure. Vibration isolation is established by minimizing signals from six acceleration sensor outputs and by steering six piezo-electric actuator inputs. Our second contribution is that a state space based fixed gain H2 controller is designed, implemented and validated. Real-time broadband feedforward control results are presented (between 0 - 1 kHz) which show that an average reduction of 8.0 dB is achieved in the error sensor outputs in real-time

    Neutrino mixing and CP violation from Dirac-Majorana bimaximal mixture and quark-lepton unification

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    We demonstrate that only two ansatz can produce the features of the neutrino mixing angles. The first ansatz comes from the quark-lepton grand unification; νDi=VCKMνα\nu_{Di} = V_{CKM} \nu_{\alpha} is satisfied for left-handed neutrinos, where νDi\nu_{Di} are the Dirac mass eigenstates and να\nu_{\alpha} are the flavour eigenstates. The second ansatz comes from the assumption; νDi=Ubimaximalνi\nu_{Di} = U_{bimaximal} \nu_{i} is satisfied between the Dirac mass eigenstates νDi\nu_{Di} and the light Majorana neutrino mass eigenstates νi\nu_{i}, where UbimaximalU_{bimaximal} is the bimaximal mixing matrix. By these two ansatz, the Maki-Nakagawa-Sakata matrix is given by UMNS=VCKMUbimaximalU_{MNS} = V_{CKM}^\dagger U_{bimaximal}. We find that in this model the novel relation θsol+θ13=π/4\theta_{sol} + \theta_{13} = \pi/4 is satisfied, where θsol\theta_{sol} and θ13\theta_{13} are solar and CHOOZ angle respectively. This "Solar-CHOOZ Complementarity" relation indicates that only if the CHOOZ angle θ13\theta_{13} is sizable, the solar angle θsol\theta_{sol} can deviate from the maximal mixing. We also infer the CP violation in neutrino oscillations. The leptonic Dirac CP phase δMNS\delta_{MNS} is predicted as sinδMNSAλ2η\sin \delta_{MNS} \simeq A \lambda^2 \eta, where A,λ,ηA, \lambda, \eta are the CKM parameters in Wolfenstein parametrization. Furthermore, we remark that the ratio of the Jarlskog CP violation factor for quarks and leptons is important, because the large uncertainty on η\eta is cancelled out in the ratio, RJJCKM/JMNS42Aλ35×102R_J \equiv J_{CKM}/J_{MNS} \simeq 4\sqrt{2} A \lambda^3 \simeq 5 \times 10^{-2}.Comment: 9 pages, no figures; v2 references added, v3 references adde
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