Homotopy equivalences between p-subgroup categories

Let p be a prime number and G a finite group of order divisible by p. Quillen showed that the Brown poset of nonidentity p-subgroups of G is homotopy equivalent to its subposet of nonidentity elementary abelian subgroups. We show here that a similar statement holds for the fusion category of nonidentity p-subgroups of G. Other categories of p-subgroups of G are also considered.Comment: 19 pages. Second versio

Cryogenic, high power, near diffraction limited, Yb:YAG slab laser

A cryogenic slab laser that is suitable for scaling to high power, while taking full advantage of the improved thermo-optical and thermo-mechanical properties of Yb:YAG at cryogenic temperatures is described. The laser uses a conduction cooled, end pumped, zigzag slab geometry resulting in a near diffraction limited, robust, power scalable design. The design and the initial characterization of the laser up to 200W are presented.Miftar Ganija, David Ottaway, Peter Veitch and Jesper Munc

Comparative studies of offices pre and post — how changing spatial configurations affect organisational behaviours

Understanding the way in which design interventions in an office affect everyday users, and thus shape organisational behaviour, should be high on the agenda for architects, designers and consultants alike. Surprisingly, this seems rarely to be the case. Here we aim to help close this gap by studying a variety of organisations in depth both before and after an office move from the point of view of design practice. This paper thus aims at understanding how a newly designed office is seen, used and filled with life by staff, so that planners can continuously and systematically reflect on and learn from experience, and create effective and well-used workplaces for the future. The research and reflective practice presented in this paper resulted from a collaboration on 'Effective Workplaces' between The Bartlett School of Graduate Studies at University College London and Spacelab architects. Insights from in-depth case studies conducted over the last four years on various corporate clients in the media sector in the UK will be drawn upon. The studies each compared an organisation before and after it moved into a Spacelab-designed office. Two different lines of argument will be presented: firstly, results of the pre-post comparison of organisations before and after moving into a newly designed space suggest that physical space influences the way in which organisations communicate, interact, and perform in many ways. Secondly, the practical side of evidence-based design will be discussed. It can be seen that designers would do things differently if they had had the specific evidence prior to the design process. At the same time, difficulties arise in conducting 'evidence-based' practice, for example the problem of time in a business environment where designers are often asked to deliver solutions within days or weeks, whereas gaining a good understanding of a complex organisation may take months. These issues will be reflected on. General conclusions on the use and usefulness of Space Syntax in an architectural practice will be drawn

New energy-transfer upconversion process in Er(3+):ZBLAN mid-infrared fiber lasers

Abstract not availableOri Henderson-Sapir, Jesper Munch, and David J. Ottawa

Who knows?

Jesper Kallestrup argues that groups can have knowledge that their members may no