Using idiothetic cues to swim a path with a fixed trajectory and distance: Necessary involvement of the hippocampus but not the retrosplenial cortex.

Rats rapidly learned to find a submerged platform in a water maze at a constant distance and angle from the start point, which changed on every trial. The rats performed accurately in the light and dark, but prior rotation disrupted the latter condition. The rats were then retested after receiving cytotoxic hippocampal or retrosplenial cortex lesions. Retrosplenial lesions had no apparent effect in either the light or dark. Hippocampal lesions impaired performance in both conditions but spared the ability to locate a platform placed in the center of the pool. A hippocampal deficit emerged when this pool-center task was run in the dark. The spatial effects of hippocampal damage extend beyond allocentric tasks to include aspects of idiothetic guidance.

Distance and Proximity in Service to the Empire: Ulster and New Zealand between the Wars

This essay uses the concepts of ‘distance’ and ‘proximity’ to investigate and assess perceptions of community, nation and empire in inter-war New Zealand and Ulster (as well as Ireland and Northern Ireland) within a British imperial context, and explores the extent to which service of the empire (for example in the First World War) promoted both notions of imperial unity and local autonomy. It focuses on how these perceptions were articulated in the inter-war years during visits to Northern Ireland by three New Zealand premiers – Massey, Forbes and Coates – and to New Zealand by the Prime Minister of Northern Ireland, Lord Craigavon. It discusses the significant ways in which distance from their ‘home base’ and proximity to expatriate communities (in Craigavon's case) and Irish unionists and nationalists (in the case of the New Zealand premiers) inflected public statements during their visits. By examining these inter-war visits and investigating the rhetoric used and the cultural demonstrations associated with them, the factors of both distance and proximity can be used to evaluate similarities and difference across two parts of the empire. Thus, we can throw some light on the nature and dynamics of British imperial identity in the early twentieth century.

Distance between home and work: A multilevel analysis of individual workers, neighbourhoods, and employment sites in Northern Ireland

Abstract. We explore the distances between home and work for employees at twenty-eight different employment sites across Northern Ireland. Substantively, this is important for better understanding the geography of labour catchments. Methodologically, with data on the distances between place of residence (566 wards) and place of work for some 15 000 workers, and the use of multilevel modelling (MLM), the analysis adds to the evidence derived from other census-based and survey-based studies. Descriptive analysis is supplemented with MLM that simultaneously explores individual, neighbourhood, and site variations in travel-to-work patterns using hierarchical and cross-classified model specifications, including individual and ecological predictor variables (and their cross-level interactions). In doing so we apportion variability to different levels and spatial contexts, and also outline the factors that shape spatial mobility. We find, as expected, that factors such as gender and occupation influence the distance between home and work, and also confirm the importance of neighbourhood characteristics (such as population density observed in ecological analyses at ward level) in shaping individual outcomes, with major differences found between urban and rural locations. Beyond this, the analysis of variability also points to the relative significance of residential location, with less individual variability in travel-to-work distance between workers within wards than within employment sites. We conclude by suggesting that, whilst some general ‘rules’ about the factors that shape labour catchments are possible (eg workers in rural areas and in higher occupations travel further than others), the complex variability between places highlighted by the MLM analysis illustrates the salience of place-specific uniqueness.

A simple game-theoretic analysis of peering and transit contracting among Internet service providers

The paper presents a simple game-theoretic model of two Internet service providers (ISPs), drawn from a larger set consisting of Tiers-1 and -2 ISPs, who choose between peering and transit agreements. The study focuses on the costs of interconnection taking into account traffic imbalances. The analysis suggests that if the traffic flows and the costs of interconnection are fairly shared, the provider's peer, otherwise they choose transit. Moreover, the joint profits are maximized under the transit arrangement. Published by Elsevier Ltd.