One brick at a time: a survey of inductive constructions in rigidity theory

We present a survey of results concerning the use of inductive constructions to study the rigidity of frameworks. By inductive constructions we mean simple graph moves which can be shown to preserve the rigidity of the corresponding framework. We describe a number of cases in which characterisations of rigidity were proved by inductive constructions. That is, by identifying recursive operations that preserved rigidity and proving that these operations were sufficient to generate all such frameworks. We also outline the use of inductive constructions in some recent areas of particularly active interest, namely symmetric and periodic frameworks, frameworks on surfaces, and body-bar frameworks. We summarize the key outstanding open problems related to inductions.Comment: 24 pages, 12 figures, final versio

Imminent Prospects for Additional Finance: What Might Be Done Now or Soon and Under What Conditions

foreign aid, taxation, subsidies, revenue, international economic order

Visual Importance-Biased Image Synthesis Animation

Present ray tracing algorithms are computationally intensive, requiring hours of computing time for complex scenes. Our previous work has dealt with the development of an overall approach to the application of visual attention to progressive and adaptive ray-tracing techniques. The approach facilitates large computational savings by modulating the supersampling rates in an image by the visual importance of the region being rendered. This paper extends the approach by incorporating temporal changes into the models and techniques developed, as it is expected that further efficiency savings can be reaped for animated scenes. Applications for this approach include entertainment, visualisation and simulation

Quantum oscillations and Berry's phase in topological insulator surface states with broken particle-hole symmetry

Quantum oscillations can be used to determine properties of the Fermi surface of metals by varying the magnitude and orientation of an external magnetic field. Topological insulator surface states are an unusual mix of normal and Dirac fermions. Unlike in graphene and simple metals, Berry's geometric phase in topological insulator surface states is not necessarily quantised. We show that reliably extracting this geometric phase from the phase offset associated with the quantum oscillations is subtle. This is especially so in the presence of a Dirac gap such as that associated with the Zeeman splitting or interlayer tunneling. We develop a semi-classical theory for general mixed normal-Dirac systems in the presence of a gap, and in doing so clarify the role of topology and broken particle-hole symmetry. We propose a systematic procedure of fitting Landau level index plots at large filling factors to reliably extract the phase offset associated with Berry's phase.Comment: 12 pages, 6 figures. Included effect of bulk Fermi surfac

Political Economy of Additional Development Finance

The paper considers the political obstacles and supports for additional development finance and a number of possible devices through which advantage may be taken of the supports and the obstacles circumvented. It emphasizes the need for effective negotiating alliances among developing-country governments that will draw on support from outside their own ranks. It gives particular attention to the 'innovative' methods by which funds might be mobilized by transnational activity for global disposal within a strategy for the progressive reduction of poverty. In order to eliminate one difficulty it outlines a possible arrangement through which funds so raised might be allocated.development finance, aid, Tobin Tax, global governance

Designing the Last Mile of the Supply Chain in Africa: Firm Expansion and Managerial Inferences from a Grocer Model of Location Decisions

The recent interest in the expansion of retail food chains and the perceived problems resulting from competition between these new, sophisticated supply chains and the most basic of food distribution networks in emerging economies have been greatly debated in the literature. This paper is a seminal approach to examining South-South food firm (grocer) foreign direct investment by incorporating data on the informal market into a facility location decision model. There are unique environmental complexities that developing/transitioning economies present. The unique finding of this model is that informal employment patterns, in both Agricultural and non-Agricultural sectors, influence the firm’s location. Given the absence of data, South-South foreign direct investment managers perceive avid market transactions as indicators of demand and potential supply availability in formal and informal sectors. For example, Pick n’ Pay’s CEO stated recently that their growth in the Southern Africa supermarket business is a direct result of the informal market converting to the formal market.Supply Chain, Africa, Informal Markets, Facility Location Model, Demand and Price Analysis, Marketing, Q10,

Dark matter, the CMSSM and lattice QCD

Recent lattice measurements have given accurate estimates of the light and strange quark condensates in the proton. We use these new results to significantly improve the dark matter predictions in a set of benchmark models that represent different scenarios in the constrained minimal supersymmetric standard model (CMSSM). Because the predicted cross sections are at least an order of magnitude smaller than previously suggested, our results have significant consequences for dark matter searches.Comment: 4 pages, 4 figure

Imminent prospects for additional finance: What might be done now or soon and under what conditions

Some of the ways that have recently been discussed for increasing significantly the own resources of developing countries, or the amount or usefulness of the overseas aid that they receive, are potentially promising politically. This is because the obstacles that they face are those of inertia or prejudice or lack of appropriate institutional channels rather than any serious countervailing interest. Several of the most important candidates, and the institutional developments that might facilitate them, are explored

An evaluation of planned exercises in meaningful writing situations as an aid to transfer of spelling ability

Thesis (Ed.M.)--Boston Universit