On integrable deformations of superstring sigma models related to AdS_n x S^n supercosets

We consider two integrable deformations of 2d sigma models on supercosets associated with AdS_n x S^n. The first, the "eta-deformation" (based on the Yang-Baxter sigma model), is a one-parameter generalization of the standard superstring action on AdS_n x S^n, while the second, the "lambda-deformation" (based on the deformed gauged WZW model), is a generalization of the non-abelian T-dual of the AdS_n x S^n superstring. We show that the eta-deformed model may be obtained from the lambda-deformed one by a special scaling limit and analytic continuation in coordinates combined with a particular identification of the parameters of the two models. The relation between the couplings and deformation parameters is consistent with the interpretation of the first model as a real quantum deformation and the second as a root of unity quantum deformation. For the AdS_2 x S^2 case we then explore the effect of this limit on the supergravity background associated to the lambda-deformed model. We also suggest that the two models may form a dual Poisson-Lie pair and provide direct evidence for this in the case of the integrable deformations of the coset associated with S^2.Comment: v2: comments and references added; v3: new appendix on an alternative proposal for the dilaton and minor changes, 28 pages; v4: misprint in (B.7) correcte

Type IIB supergravity solution for the T-dual of the eta-deformed AdS_5 x S^5 superstring

We find an exact type IIB supergravity solution that represents a one-parameter deformation of the T-dual of the AdS_5 x S^5 background (with T-duality applied in all 6 abelian bosonic isometric directions). The non-trivial fields are the metric, dilaton and RR 5-form only. The latter has remarkably simple "undeformed" form when written in terms of a "deformation-rotated" vielbein basis. An unusual feature of this solution is that the dilaton contains a linear dependence on the isometric coordinates of the metric precluding a straightforward reversal of T-duality. If we still formally dualize back, we find exactly the metric, B-field and product of dilaton with RR field strengths as recently extracted from the eta-deformed AdS_5 x S^5 superstring action in arXiv:1507.04239. We also discuss similar solutions for deformed AdS_n x S^n backgrounds with n=2,3. In the eta -> i limit we demonstrate that all these backgrounds can be interpreted as special limits of gauged WZW models and are also related to (a limit of) the Pohlmeyer-reduced models of the AdS_n x S^n superstrings.Comment: 20 pages; v2: minor comments and clarifications added; v3: 21 pages, minor comments and references adde

Type IIB supergravity solution for the T-dual of the eta-deformed AdS_5 x S^5 superstring

We find an exact type IIB supergravity solution that represents a one-parameter deformation of the T-dual of the AdS_5 x S^5 background (with T-duality applied in all 6 abelian bosonic isometric directions). The non-trivial fields are the metric, dilaton and RR 5-form only. The latter has remarkably simple "undeformed" form when written in terms of a "deformation-rotated" vielbein basis. An unusual feature of this solution is that the dilaton contains a linear dependence on the isometric coordinates of the metric precluding a straightforward reversal of T-duality. If we still formally dualize back, we find exactly the metric, B-field and product of dilaton with RR field strengths as recently extracted from the eta-deformed AdS_5 x S^5 superstring action in arXiv:1507.04239. We also discuss similar solutions for deformed AdS_n x S^n backgrounds with n=2,3. In the eta -> i limit we demonstrate that all these backgrounds can be interpreted as special limits of gauged WZW models and are also related to (a limit of) the Pohlmeyer-reduced models of the AdS_n x S^n superstrings.Comment: 20 pages; v2: minor comments and clarifications added; v3: 21 pages, minor comments and references adde

How is toxicity managed within online games by their companies?

The term toxic is a widely used term within the gaming industry, used to label behaviours and actions witnessed within the gaming community, to various articles of research discussing this topic. This thesis discusses how toxic has several other terms often tied to the behaviour that goes against the collective norm (Erikson, 1962, Dobbert and Mackey, 2015) of the gaming community while suggesting ways for companies to combat this behaviour. Both deviant (Erikson, 1962, Suler, 2004, Clinard and Meier, 2014, Dobbert and Mackey, 2015) and transgressive (Jenks, 2003 Meades, 2015) can be used to highlight this type of behaviour. Due to this, clearly defining what is toxic, deviant or transgressive is difficult as this relies on a subject perspective that others may not share. Thus, this thesis studies the broad rules implemented by the gaming companies to further understand what can be highlighted as toxic behaviour before observing player-to-player interactions. From the data gathered, it is then vital for companies to continue to monitor their players to ensure the safety of the community. While the steps the companies have taken shows they have listened to the community, the report function is still vital to monitor for this deviant, transgressive or even toxic behaviour. Overall, I believe that from my own research I encountered more deviant and transgressive behaviour than toxic

The Enigma of Host-Parasite Relations in Amebiasis

Talk given by Cecil A. Hoare from the Wellcome Laboratories of Tropical Medicine, London, Englan