472 research outputs found

    The Origins of Terrorism: Cross-Country Estimates on Socio-economic Determinants of Terrorism

    Get PDF
    As a prerequisite of an appropriate anti-terror strategy, it is indispensable to assess the underlying causes of terror. We examine social and economic conditions in the country of origin of terrorist attacks, claiming that low opportunity costs of terror, e.g., approximated by slow growth and poor institutions raise the likelihood of terror and the willingness in the population to support terror. Using a negative binomial regression model, we are able to show that unfortunate socio-economic conditions in a country are likely to reduce the opportunity costs of potential terrorists and increase the number of terrorist attacks originating from a specific country. Interestingly, this effect is particularly relevant after a certain level of development has been reached. We therefore distinguish between several broad country groups, namely the OECD, Europe and Islamic countries.terror attacks, openness, discrete choice analysis, institutions

    The Origins of Terrorism - Cross-Country Estimates on Socio-Economic Determinants of Terrorism

    Get PDF
    To expand our knowledge about an appropriate anti-terror strategy, it is indispensable to assess the underlying causes of terror. We examine social and economic conditions in the country of origin of terrorist attacks, claiming that low opportunity costs of terror, e.g. approximated as slow growth and poor institutions raise the propensity of terror and the willingness in the population to support terror. Using a mixed effects Poisson regression model, we are able to show that unfortunate socio-economic conditions in a country are suitable to reduce the opportunity cost for potential terrorists and increase the likelihood of terrorist attacks originating from a specific country. Interestingly, this effect is relevant after a certain level of development has been reached. We therefore distinguish between the OECD, Europe and Islamic countries.terror attacks, openness, discrete choice analysis, institutions

    The Origins of Terrorism: Cross-Country Estimates on Socio-economic Determinants of Terrorism

    Full text link
    As a prerequisite of an appropriate anti-terror strategy, it is indispensable to assess the underlying causes of terror. We examine social and economic conditions in the country of origin of terrorist attacks, claiming that low opportunity costs of terror, e.g., approximated by slow growth and poor institutions raise the likelihood of terror and the willingness in the population to support terror. Using a negative binomial regression model, we are able to show that unfortunate socio-economic conditions in a country are likely to reduce the opportunity costs of potential terrorists and increase the number of terrorist attacks originating from a specific country. Interestingly, this effect is particularly relevant after a certain level of development has been reached. We therefore distinguish between several broad country groups, namely the OECD, Europe and Islamic countries

    The origins of terrorism cross-country estimates on socio-economic determinants of terrorism

    Full text link
    To expand our knowledge about an appropriate anti-terror strategy, it is indispensable to assess the underlying causes of terror. We examine social and economic conditions in the country of origin of terrorist attacks, claiming that low opportunity costs of terror, e.g. approximated as slow growth and poor institutions raise the propensity of terror and the willingness in the population to support terror. Using a mixed effects Poisson regression model, we are able to show that unfortunate socio-economic conditions in a country are suitable to reduce the opportunity cost for potential terrorists and increase the likelihood of terrorist attacks originating from a specific country. Interestingly, this effect is relevant after a certain level of development has been reached. We therefore distinguish between the OECD, Europe and Islamic countries

    The spin 1/2 Heisenberg star with frustration II: The influence of the embedding medium

    Full text link
    We investigate the spin 1/2 Heisenberg star introduced in J. Richter and A. Voigt, J. Phys. A: Math. Gen. {\bf 27}, 1139 (1994). The model is defined by H=J1i=1Ns0si+J2HR{si}H=J_1 \sum_{i=1}^{N}{{\bf s}_0{\bf s}_i} + J_2 H_{R}\{{\bf s}_i\} ; J1,J20J_1,J_2 \ge 0 , i=1,...,Ni=1,...,N. In extension to the Ref. we consider a more general HR{si}H_{R}\{{\bf s}_i\} describing the properties of the spins surrounding the central spin s0{\bf s}_0. The Heisenberg star may be considered as an essential structure element of a lattice with frustration (namely a spin embedded in a magnetic matrix HRH_R) or, alternatively, as a magnetic system HR H_R with a perturbation by an extra spin. We present some general features of the eigenvalues, the eigenfunctions as well as the spin correlation s0si\langle {\bf s}_0{\bf s}_i \rangle of the model. For HRH_R being a linear chain, a square lattice or a Lieb-Mattis type system we present the ground state properties of the model in dependence on the frustration parameter α=J2/J1\alpha=J_2/J_1. Furthermore the thermodynamic properties are calculated for HRH_R being a Lieb--Mattis antiferromagnet.Comment: 16 pages, uuencoded compressed postscript file, accepted to J. Phys. A: Math. Ge

    Hydrodynamic coupling and rotational mobilities near planar elastic membranes

    Get PDF
    We study theoretically and numerically the coupling and rotational hydrodynamic interactions between spherical particles near a planar elastic membrane that exhibits resistance towards shear and bending. Using a combination of the multipole expansion and Faxen's theorems, we express the frequency-dependent hydrodynamic mobility functions as a power series of the ratio of the particle radius to the distance from the membrane for the self mobilities, and as a power series of the ratio of the radius to the interparticle distance for the pair mobilities. In the quasi-steady limit of zero frequency, we find that the shear- and bending-related contributions to the particle mobilities may have additive or suppressive effects depending on the membrane properties in addition to the geometric configuration of the interacting particles relative to the confining membrane. To elucidate the effect and role of the change of sign observed in the particle self and pair mobilities, we consider an example involving a torque-free doublet of counterrotating particles near an elastic membrane. We find that the induced rotation rate of the doublet around its center of mass may differ in magnitude and direction depending on the membrane shear and bending properties. Near a membrane of only energetic resistance toward shear deformation, such as that of a certain type of elastic capsules, the doublet undergoes rotation of the same sense as observed near a no-slip wall. Near a membrane of only energetic resistance toward bending, such as that of a fluid vesicle, we find a reversed sense of rotation. Our analytical predictions are supplemented and compared with fully resolved boundary integral simulations where a very good agreement is obtained over the whole range of applied frequencies.Comment: 14 pages, 7 figures. Revised manuscript resubmitted to J. Chem. Phy
    corecore