Hamburg's warehouse district in Martin tom Dieck's "hundert Ansichten der Speicherstadt"

Most texts that deal with Martin tom Dieck’s black-and-white comic "hundert Ansichten der Speicherstadt" (Zürich: Arrache Cœur, 1997, French title: Vortex) claim that it depicts the eponymous warehouse district (Speicherstadt) in Hamburg. As this paper shows, this claim is inaccurate: although the architecture in tom Dieck’s drawings clearly refers to buildings in the warehouse district, the differences in the details are so obvious, that to speak of a straightforward depiction of the Speicherstadt is oversimplifying. After a brief comparison with Christoph Schäfer’s picture book "Die Stadt ist unsere Fabrik" (Leipzig: Spector Books, 2010), the paper concludes with a discussion of the depiction of urban environments in general and in tom Dieck's book in particular

Heavy Z': resonant versus non-resonant searches

Collider searches for new vector-like particles such as Z' have mostly been pursued by looking for a peak in the invariant mass spectrum of the decay products. However off-shell Z' exchange may leave an imprint on other kinematic distributions, leading thus to non-resonant searches. The aim of this paper is to assess, in the context of the LHC, the interplay between resonant (s-channel) and non-resonant (t-channel) searches for a generic leptophobic Z' model. We show in particular that while non-resonant searches are less sensitive to small couplings, they tend to be more adapted at high masses and large couplings. We discuss our findings both at the level of the current limits and the expectations at higher luminosities

Mapping class groups and outer automorphism groups of free groups are C*-simple

We prove that the reduced C*-algebras of centerless mapping class groups and outer automorphism groups of free groups are simple, as are the irreducible pure subgroups of mapping class groups and the analogous subgroups of outer automorphism groups of free groups.Comment: 10 pages, amstex. J. Functional Analysis, to be publishe

Vector-like quarks with a scalar triplet

We study a minimal extension to the Standard Model with an additional real scalar triplet, $\Sigma$, and a single vector-like quark, $T$. This class of models appear naturally in extensions of the Littlest Higgs model that incorporate dark matter without the need of $T$-parity. We assume the limit that the triplet does not develop a vacuum expectation value and that all dimension five operators coupling the triplet to Standard Model fields and the vector-like quarks are characterized by the scale $\Lambda$ at which we expect new physics to arise. We introduce new non-renormalizable interactions between the new scalar sector and fermion sector that allow mixing between the Standard Model third generation up-type quark and the vector-like quark in a way that leads to the cancellation of the leading quadratic divergences to the one-loop corrections from the top quark to the mass of the Higgs boson. Within this framework, new decay modes of the vector-like quark to the real scalar triplet and SM particles arise and bring forth an opportunity to probe this model with existing and future LHC data. We contrast constraints from direct colliders searches with low energy precision measurements and find that heavy vector-like top quarks with a mass as low as $650$ GeV are consistent with current experimental constraints in models where new physics arises at scales below $2$ TeV

The Chabauty space of closed subgroups of the three-dimensional Heisenberg group

When equipped with the natural topology first defined by Chabauty, the closed subgroups of a locally compact group $G$ form a compact space \Cal C(G). We analyse the structure of \Cal C(G) for some low-dimensional Lie groups, concentrating mostly on the 3-dimensional Heisenberg group $H$. We prove that \Cal C(H) is a 6-dimensional space that is path--connected but not locally connected. The lattices in $H$ form a dense open subset \Cal L(H) \subset \Cal C(H) that is the disjoint union of an infinite sequence of pairwise--homeomorphic aspherical manifolds of dimension six, each a torus bundle over $(\bold S^3 \smallsetminus T) \times \bold R$, where $T$ denotes a trefoil knot. The complement of \Cal L(H) in \Cal C(H) is also described explicitly. The subspace of \Cal C(H) consisting of subgroups that contain the centre $Z(H)$ is homeomorphic to the 4--sphere, and we prove that this is a weak retract of \Cal C(H).Comment: Minor edits. Final version. To appear in the Pacific Journal. 41 pages, no figure

New Zealand Working For Families programme: Literature review of evaluation evidence

In 2005, the Ministry of Social Development (MSD) commissioned research to review international evaluation methodology and literature to help in the preparation of evaluation of the Working for Families (WFF) policy, introduced in 2004 to assist working low- and middle-income families in New Zealand. The results of the study are in two parts: Working for Families: Methodological considerations in evaluating the programme and Working for Families: Literature review of evaluation evidence. This first part, the literature review, reviews international literature, comparing the economic impact of WFF with those of welfare reforms elsewhere. It introduces the central issues within the New Zealand and WFF context using a combination of cross-national comparisons and an intensive country or programme literature review. This provides a good balance between depth and coverage and enables a consistent method of review. Research findings are aimed at government social researchers and will enable evaluation to be carried out on WFF based on a sound understanding of current international evidence and benchmarking.