24/7 population modelling for enhanced assessment of exposure to natural hazards

There is a growing need for accurate spatio-temporal population estimates free from arbitrary administrative boundaries and temporal divisions to make enhanced assessments of population exposure to natural hazards. The approach proposed here combines the use of a spatio-temporal gridded population model to estimate temporary variations in population with natural hazard exposure estimations. It has been exemplified through a Southampton (UK) centred application using Environment Agency flood map inundation data. Results demonstrate that large fluctuations in the population within flood risk zones occur. Analysis indicates a diurnal shift in exposure to fluvial and tidal flooding, particularly attributed to the working age population. This highlights the improvements achievable to flood risk management as well as potential application to other natural hazard scenarios both within the UK and globally

Responding to a world of change

The BGS is proud of the central role our surveying has played in the development of geology as a science. We are equally proud of our contribution to the understanding of key issues such as the age and evolution of the Earth and life, the origin and classification of rocks, and the impact of humans on the earth system. With 175 years of dedicated surveying behind us, the UK is already better served with geological information than most other countries. However, in today’s rapidly evolving, knowledge-based economy, we must continually adapt our surveying to meet the changing needs of society

Little Higgs Review

Recently there has been renewed interest in the possibility that the Higgs particle of the Standard Model is a pseudo-Nambu-Goldstone boson. This development was spurred by the observation that if certain global symmetries are broken only by the interplay between two or more coupling constants, then the Higgs mass-squared is free from quadratic divergences at one loop. This "collective symmetry" breaking is the essential ingredient in little Higgs theories, which are weakly coupled extensions of the Standard Model with little or no fine tuning, describing physics up to an energy scale ~10 TeV. Here we give a pedagogical introduction to little Higgs theories. We review their structure and phenomenology, focusing mainly on the SU(3) theory, the Minimal Moose, and the Littlest Higgs as concrete examples.Comment: To appear in Annual Review of Nuclear and Particle Science; contains TASI'05 Little Higgs lecture notes, 44 page

Tragedy of the Commons in the Chemostat

We present a proof of principle for the phenomenon of the tragedy of the commons that is at the center of many theories on the evolution of cooperation. We establish the tragedy in the context of a general chemostat model with two species, the cooperator and the cheater. Both species have the same growth rate function and yield constant, but the cooperator allocates a portion of the nutrient uptake towards the production of a public good -the "Commons" in the Tragedy- which is needed to digest the externally supplied nutrient. The cheater on the other hand does not produce this enzyme, and allocates all nutrient uptake towards its own growth. We prove that when the cheater is present initially, both the cooperator and the cheater will eventually go extinct, hereby confirming the occurrence of the tragedy. We also show that without the cheater, the cooperator can survive indefinitely, provided that at least a low level of public good or processed nutrient is available initially. Our results provide a predictive framework for the analysis of cooperator-cheater dynamics in a powerful model system of experimental evolution.Comment: 23 pages, 4 figure

Resisting assimilation: survival and adaptation to 'alien' accomodation forms: The case of British Gypsy/Travellers in housing

This paper consists of discussion of findings from a series of empirical studies conducted in London and southern England. A central concern of these studies was to explore the collective responses and adaptations of Gypsies and Travellers to post-war (1945) government legislation which has aimed to eradicate nomadic lifestyles and in so doing, to settle and assimilate this group into the general population. Despite these policy objectives Gypsies and Travellers through utilising forms of cultural resilience have resisted enormous pressures to assimilate, managing to live within a wider culture while rejecting its values and social institutions and recreating traditional collective lifestyles (as far as possible) within 'bricks and mortar' accommodation. The authors outline contemporary forms of resistance to assimilation and, by drawing on qualitative and ethnographic data, demonstrate how relations between the state and Gypsies and Travellers is characterised by a cyclical relationship of domination, resistance and resilience. As legislation is enacted to restrict the mobility of Gypsies and Travellers and 'settle' them, so these groups develop innovative startegies to evade or minimise the impact of legislation, thus instigating a new phase of policy development. Cultural resilience in this context therefore encompasses active resistance to externally imposed changes that are perceived as antithetical to traditional lifestyles. Drawing on Acton's (1974) typology of adaptive strategies the authors illustrate how recourse to culturally grounded strategies of resistance has allowed Gypsies and Travellers to maintain a sense of social cohesion and group identity, which assists in minimising the more damaging impacts of legislation

Algebraic and combinatorial aspects of sandpile monoids on directed graphs

The sandpile group of a graph is a well-studied object that combines ideas from algebraic graph theory, group theory, dynamical systems, and statistical physics. A graph's sandpile group is part of a larger algebraic structure on the graph, known as its sandpile monoid. Most of the work on sandpiles so far has focused on the sandpile group rather than the sandpile monoid of a graph, and has also assumed the underlying graph to be undirected. A notable exception is the recent work of Babai and Toumpakari, which builds up the theory of sandpile monoids on directed graphs from scratch and provides many connections between the combinatorics of a graph and the algebraic aspects of its sandpile monoid. In this paper we primarily consider sandpile monoids on directed graphs, and we extend the existing theory in four main ways. First, we give a combinatorial classification of the maximal subgroups of a sandpile monoid on a directed graph in terms of the sandpile groups of certain easily-identifiable subgraphs. Second, we point out certain sandpile results for undirected graphs that are really results for sandpile monoids on directed graphs that contain exactly two idempotents. Third, we give a new algebraic constraint that sandpile monoids must satisfy and exhibit two infinite families of monoids that cannot be realized as sandpile monoids on any graph. Finally, we give an explicit combinatorial description of the sandpile group identity for every graph in a family of directed graphs which generalizes the family of (undirected) distance-regular graphs. This family includes many other graphs of interest, including iterated wheels, regular trees, and regular tournaments.Comment: v2: Cleaner presentation, new results in final section. Accepted for publication in J. Combin. Theory Ser. A. 21 pages, 5 figure

Performance and loads data from an outdoor hover test of a Lynx tail rotor

A Lynx tail rotor was tested in hover at the Outdoor Aerodynamic Research Facility at NASA Ames Research Center. The test objectives were to measure the isolated rotor performance to provide a baseline for subsequent testing, and to operate the rotor throughout the speed and collective envelope before testing in the NFAC 40- by 80-Foot Wind Tunnel. Rotor forces and blade bending moments were measured at ambient wind conditions from zero to 6.23 m/sec. The test envelope was limited to rotor speeds of 1550 to 1850 rpm and minus 13 deg to plus 20 deg of blade collective pitch. The isolated rotor performance and blade loads data are presented

The Starpicker expert system: A problem in expertise capture

This paper describes the Starpicker expert system, a tool for spacecraft operations planning. Both programmatic and technical aspects are discussed

Dimensions of participation. Experiences, lessons and tips from agricultural research practitioners in Sub-Saharan Africa

This book is about participation in agricultural research. It documents the experience of practitioners in implementing agricultural research projects in which participation has been a central issue. This experience is documented through case studies, and through summaries of the authors' experience. Reference is made to other literature on aspects of participation, both specific and general. The case studies give first hand accounts of the challenges and successes involved in using participatory approaches in agricultural research projects undertaking technology development and adaptation. Written by practitioners, the case studies cover many practical aspects of design and implementation that are not covered in more academic and conceptual writing on this subject, or in general manuals on how to undertake participatory agricultural research. The existing books, manuals and guidelines adequately outline the key principles and approaches in participatory agricultural research (e.g. Okali et al., 1994; Van Veldhuizen et al., 1997; Sutherland, 1998). This book is different from most others on participatory agricultural research in the following respects: it organizes and compares case-study experiences within topical chapters, rather than having case studies written as separate chapters; it embraces a wider view of participation- in addition to interaction between farmers and researchers, this view includes participation both within project teams and between the project team and other stakeholders in the agricultural research process; it is not a training manual detailing what to do, when to do it and how; however, lessons and tips are provided for the topics covered; it is rooted in project experiences rather than in development discourse, and does not advocate a particular participatory research philosophy, or claim to break new ground in terms of participatory concepts and methods. The aim of the book is to stimulate learning, primarily by presenting examples of how a range of projects handled various components of the participatory research process. These examples are given within a broader discussion of the typical challenges and issues faced by projects and practitioners when using participatory approaches to develop and adapt agricultural technology. Drawing on the case studies and other experiences, some lessons, strategies and tips are outlined in relation to particular topics within participatory agricultural research