Notes on the migration and dispersal of birds at Kitui

Volume: XXI

Notes on the birds of Kakamega forest

Volume: XX

Parametricity and Local Variables

We propose that the phenomenon of local state may be understood in terms of Strachey\u27s concept of parametric (i.e., uniform) polymorphism. The intuitive basis for our proposal is the following analogy: a non-local procedure is independent of locally-declared variables in the same way that a parametrically polymorphic function is independent of types to which it is instantiated. A connection between parametricity and representational abstraction was first suggested by J. C. Reynolds. Reynolds used logical relations to formalize this connection in languages with type variables and user-defined types. We use relational parametricity to construct a model for an Algol-like language in which interactions between local and non-local entities satisfy certain relational criteria. Reasoning about local variables essentially involves proving properties of polymorphic functions. The new model supports straightforward validations of all the test equivalences that have been proposed in the literature for local-variable semantics, and encompasses standard methods of reasoning about data representations. It is not known whether our techniques yield fully abstract semantics. A model based on partial equivalence relations on the natural numbers is also briefly examined

Augmented analyses: supporting the study of ubiquitous computing systems

Ubiquitous computing is becoming an increasingly prevalent part of our everyday lives. The reliance of society upon such devices as mobile phones, coupled with the increasing complexity of those devices is an example of how our everyday human-human interaction is affected by this phenomenon. Social scientists studying human-human interaction must now take into account the effects of these technologies not just on the interaction itself, but also on the approach required to study it. User evaluation is a challenging topic in ubiquitous computing. It is generally considered to be difficult, certainly more so than in previous computational settings. Heterogeneity in design, distributed and mobile users, invisible sensing systems and so on, all add up to render traditional methods of observation and evaluation insufficient to construct a complete view of interactional activity. These challenges necessitate the development of new observational technologies. This thesis explores some of those challenges and demonstrates that system logs, with suitable methods of synchronising, filtering and visualising them for use in conjunction with more traditional observational approaches such as video, can be used to overcome many of these issues. Through a review of both the literature of the field, and the state of the art of computer aided qualitative data analysis software (CAQDAS), a series of guidelines are constructed showing what would be required of a software toolkit to meet the challenges of studying ubiquitous computing systems. It outlines the design and implementation of two such software packages, \textit{Replayer} and \textit{Digital Replay System}, which approach the problem from different angles, the former being focussed on visualising and exploring the data in system logs and the latter focussing on supporting the methods used by social scientists to perform qualitative analyses. The thesis shows through case studies how this technique can be applied to add significant value to the qualitative analysis of ubiquitous computing systems: how the coordination of system logs and other media can help us find information in the data that would otherwise be inaccessible; an ability to perform studies in locations/settings that would otherwise be impossible, or at least very difficult; and how creating accessible qualitative data analysis tools allows people to study particular settings or technologies who could not have studied them before. This software aims to demonstrate the direction in which other CAQDAS packages may have to move in order to support the study of the characteristics of human-computer and human-human interaction in a world increasingly reliant upon ubiquitous computing technology

The strong influence of substrate conductivity on droplet evaporation

We report the results of physical experiments that demonstrate the strong influence of the thermal conductivity of the substrate on the evaporation of a pinned droplet. We show that this behaviour can be captured by a mathematical model including the variation of the saturation concentration with temperature, and hence coupling the problems for the vapour concentration in the atmosphere and the temperature in the liquid and the substrate. Furthermore, we show that including two ad hoc improvements to the model, namely a Newton's law of cooling on the unwetted surface of the substrate and the buoyancy of water vapour in the atmosphere, give excellent quantitative agreement for all of the combinations of liquid and substrate considered

Syntactic Control of Interference Revisited

In Syntactic Control of Interference (POPL, 1978), J. C. Reynolds proposes three design principles intended to constrain the scope of imperative state effects in Algol-like languages. The resulting linguistic framework seems to be a very satisfactory way of combining functional and imperative concepts, having the desirable attributes of both purely functional languages (such as pcf) and simple imperative languages (such as the language of while programs). However, Reynolds points out that the obvious syntax for interference control has the unfortunate property that fi-reductions do not always preserve typings. Reynolds has subsequently presented a solution to this problem (ICALP, 1989), but it is fairly complicated and requires intersection types in the type system. Here, we present a much simpler solution which does not require intersection types. We first describe a new type system inspired in part by linear logic and verify that reductions preserve typings. We then define a class of bireflective models, which provide a categorical analysis of structure underlying the new typing rules; a companion paper Bireflectivity, in this volume, exposes wider ramifications of this structure. Finally, we describe a concrete model for an illustrative programming language based on the new type system; this improves on earlier such efforts in that states are not assumed to be structured using locations

The Nottingham Multi-Modal Corpus: a demonstration

This software demonstration overviews the developments made during the 3-year NCeSS funded Understanding New Forms of the Digital Record for e-Social Science project (DReSS) that was based at the University of Nottingham. The demo highlights the outcomes of a specific ‘driver project’ hosted by DReSS, which sought to combine the knowledge of linguists and the expertise of computer scientists in the construction of the multi-modal (MM hereafter) corpus software: the Digital Replay System (DRS). DRS presents ‘data’ in three different modes, as spoken (audio), video and textual records of real-life interactions, accurately aligning within a functional, searchable corpus setting (known as the Nottingham Multi-Modal Corpus: NMMC herein). The DRS environment therefore allows for the exploration of the lexical, prosodic and gestural features of conversation and how they interact in everyday speech. Further to this, the demonstration introduces a computer vision based gesture recognition system which has been constructed to allow for the detection and preliminary codification of gesture sequences. This gesture tracking system can be imported into DRS to enable an automated approach to the analysis of MM datasets

Plasmin activity promotes amyloid deposition in a transgenic model of human transthyretin amyloidosis

Cardiac ATTR amyloidosis, a serious but much under-diagnosed form of cardiomyopathy, is caused by deposition of amyloid fibrils derived from the plasma protein transthyretin (TTR), but its pathogenesis is poorly understood and informative in vivo models have proved elusive. Here we report the generation of a mouse model of cardiac ATTR amyloidosis with transgenic expression of human TTRS52P. The model is characterised by substantial ATTR amyloid deposits in the heart and tongue. The amyloid fibrils contain both full-length human TTR protomers and the residue 49-127 cleavage fragment which are present in ATTR amyloidosis patients. Urokinase-type plasminogen activator (uPA) and plasmin are abundant within the cardiac and lingual amyloid deposits, which contain marked serine protease activity; knockout of α2-antiplasmin, the physiological inhibitor of plasmin, enhances amyloid formation. Together, these findings indicate that cardiac ATTR amyloid deposition involves local uPA-mediated generation of plasmin and cleavage of TTR, consistent with the previously described mechano-enzymatic hypothesis for cardiac ATTR amyloid formation. This experimental model of ATTR cardiomyopathy has potential to allow further investigations of the factors that influence human ATTR amyloid deposition and the development of new treatments

Constraints on the Ultra High Energy Photon flux using inclined showers from the Haverah Park array

We describe a method to analyse inclined air showers produced by ultra high energy cosmic rays using an analytical description of the muon densities. We report the results obtained using data from inclined events (60^{\circ}<\theta<80^{\circ}) recorded by the Haverah Park shower detector for energies above 10^19 eV. Using mass independent knowledge of the UHECR spectrum obtained from vertical air shower measurements and comparing the expected horizontal shower rate to the reported measurements we show that above 10^19 eV less than 48 % of the primary cosmic rays can be photons at the 95 % confidence level and above 4 X 10^19 eV less than 50 % of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultra high-energy cosmic rays.Comment: 45 pages, 25 figure