Mobility and distance decay at the aggregated and individual level

Most crimes are committed near to where the offender lives; this has been observed both at the aggregate and at the offender level. At the aggregate level, as the distance increases there is a decline in the number of offences committed, and initially this decline is quite slow. This pattern has been described by a number of researchers, and results in a distance decay curve. Near-home offending has also been observed at the level of the individual offender, although it has been debated whether distance decay actually exists at the level of the individual offender. We therefore believe it is important to distinguish near-home offending from decay, i.e. the gradual decline in offences as distances increase. This paper studies mobility patterns and decay curves on serious property crimes in Belgium. First, aggregated patterns are discussed and categorised. Second, individual offenders are analysed. It becomes clear through studying offender patterns that offender mobility and decay are not intertwined at the individual level to the same extent as they are at the aggregate level. This suggests that it is important, particularly when studying individual offenders, to clarify whether (average) distances or decay are being considered

Yang-Baxter deformations, AdS/CFT, and twist-noncommutative gauge theory

We give an AdS/CFT interpretation to homogeneous Yang-Baxter deformations of the AdS_5 x S^5 superstring as noncommutative deformations of the dual gauge theory, going well beyond the canonical noncommutative case. These homogeneous Yang-Baxter deformations can be of so-called abelian or jordanian type. While abelian deformations have a clear interpretation in string theory and many already had well understood gauge theory duals, jordanian deformations appear novel on both counts. We discuss the symmetry structure of the deformed string from the uniformizing perspective of Drinfeld twists and indicate that this structure can be realized on the gauge theory side by considering theories on various noncommutative spaces. We then conjecture that these are the gauge theory duals of our strings, modulo subtleties involving singularities. We support this conjecture by a brane construction for two jordanian examples, corresponding to noncommutative spaces with [x^-,x^i] ~ x^i (i=1,2). We also discuss kappa-Minkowski type deformations of AdS_5 x S^5, one of which may be the gravity dual of gauge theory on spacelike kappa-Minkowski space.Comment: v5, published version up to formatting, 32 page

Civil society organizations at the gates? A gatekeeping study of news making efforts by NGOs and government institutions

This article applies a combination of an input-output content analysis and in-depth interviews with NGO communication professionals to determine whether the growing incorporation of press releases in editorial print content could be a new public forum through which international political actors, such as NGOs, could gain wider news access by serving as emerging key players in global civil society. The study indicates that Belgian news coverage of international aid issues is more often based on NGO press releases than government press releases. We also found that the agenda building capacities of NGOs and government institutions are enhanced as journalists present information subsidies as original journalistic work in most cases. Nonetheless, we must tone down prevailing one-sided conclusions, as most press releases are not just copy-pasted. Instead, most are supplemented with additional sources and information. The data, moreover, identify different journalistic roles of NGOs according to their objectives. While some issue press releases to raise short-term public awareness and donations for humanitarian crises (mobilization), others have developed into established expert news source organizations which provide background information and reliable eyewitness accounts to journalists

Double Wick rotating Green-Schwarz strings

Via an appropriate field redefinition of the fermions, we find a set of conditions under which light cone gauge fixed world sheet theories of strings on two different backgrounds are related by a double Wick rotation. These conditions take the form of a set of transformation laws for the background fields, complementing a set of transformation laws for the metric and B field we found previously with a set for the dilaton and RR fields, and are compatible with the supergravity equations of motion. Our results prove that at least to second order in fermions, the AdS_5 x S^5 mirror model which plays an important role in the field of integrability in AdS/CFT, represents a string on `mirror AdS_5 x S^5', the background that follows from our transformations. We discuss analogous solutions for AdS_3 x S^3 x T^4 and AdS_2 x S^2 x T^6. The main ingredient in our derivation is the light cone gauge fixed action for a string on an (almost) completely generic background, which we explicitly derive to second order in fermions.Comment: v2, updated discussion on target space interpretation, elaborated discussion on minor points, content matches published version, 28 pages, 3 figure

Realizations of coupled vectors in the tensor product of representations of su(1,1) and su(2)

AbstractUsing the realization of positive discrete series representations of su(1,1) in terms of a complex variable z, we give an explicit expression for coupled basis vectors in the tensor product of ν+1 representations as polynomials in ν+1 variables z1,…,zν+1. These expressions use the terminology of binary coupling trees (describing the coupled basis vectors), and are explicit in the sense that there is no reference to the Clebsch–Gordan coefficients of su(1,1). In general, these polynomials can be written as (terminating) multiple hypergeometric series. For ν=2, these polynomials are triple hypergeometric series, and a relation between the two binary coupling trees yields a relation between two triple hypergeometric series. The case of su(2) is discussed next. Also here the polynomials are determined explicitly in terms of a known realization; they yield an efficient way of computing coupled basis vectors in terms of uncoupled basis vectors

Quantum Spectral Curve for the eta-deformed AdS_5xS^5 superstring

The spectral problem for the ${\rm AdS}_5\times {\rm S}^5$ superstring and its dual planar maximally supersymmetric Yang-Mills theory can be efficiently solved through a set of functional equations known as the quantum spectral curve. We discuss how the same concepts apply to the $\eta$-deformed ${\rm AdS}_5\times {\rm S}^5$ superstring, an integrable deformation of the ${\rm AdS}_5\times {\rm S}^5$ superstring with quantum group symmetry. This model can be viewed as a trigonometric version of the ${\rm AdS}_5\times {\rm S}^5$ superstring, like the relation between the XXZ and XXX spin chains, or the sausage and the ${\rm S}^2$ sigma models for instance. We derive the quantum spectral curve for the $\eta$-deformed string by reformulating the corresponding ground-state thermodynamic Bethe ansatz equations as an analytic $Y$ system, and map this to an analytic $T$ system which upon suitable gauge fixing leads to a $\mathbf{P} \mu$ system -- the quantum spectral curve. We then discuss constraints on the asymptotics of this system to single out particular excited states. At the spectral level the $\eta$-deformed string and its quantum spectral curve interpolate between the ${\rm AdS}_5\times {\rm S}^5$ superstring and a superstring on "mirror" ${\rm AdS}_5\times {\rm S}^5$, reflecting a more general relationship between the spectral and thermodynamic data of the $\eta$-deformed string. In particular, the spectral problem of the mirror ${\rm AdS}_5\times {\rm S}^5$ string, and the thermodynamics of the undeformed ${\rm AdS}_5\times {\rm S}^5$ string, are described by a second rational limit of our trigonometric quantum spectral curve, distinct from the regular undeformed limit.Comment: 32+37 pages; 6 figures. v2: added reference

Fermionic reductions of the AdS4 x CP3 superstring

We discuss fermionic reductions of type IIA superstrings on AdS4 x CP3 in relation to the conjectured AdS4/CFT3 duality. The superstring theory is described by means of a coset model construction, which is classically integrable. We discuss the global light-cone symmetries of the action and related kappa-symmetry gauge choices, and also present the complete quartic action in covariant form with respect to these. Further, we study integrable (fermionic) reductions, in particular, a reduction yielding a quadratic action of two complex fermions on the string world-sheet. Interestingly, this model appears to be exactly the same as the corresponding integrable reduction found in the AdS5 x S5 case.Comment: 24 pages, v3 as publishe