Asymptotic behaviour of random Markov chains with tridiagonal generators

Continuous-time discrete-state random Markov chains generated by a random linear differential equation with a random tridiagonal matrix are shown to have a random attractor consisting of singleton subsets, essentially a random path, in the simplex of probability vectors. The proof uses comparison theorems for Carath\'eodory random differential equations and the fact that the linear cocycle generated by the Markov chain is a uniformly contractive mapping of the positive cone into itself with respect to the the Hilbert projective metric. It does not involve probabilistic properties of the sample path and is thus equally valid in the nonautonomous deterministic context of Markov chains with, say, periodically varying transitions probabilities, in which case the attractor is a periodic path.Comment: 11 pages, 15 bibliography references, added bibliography, minor change

Report on 1:100 000 Scale Geological and Metallogenic Maps Sheet 3163-19 Cosquín, Province of Córdoba

Fil: Stuart-Smith, Peter G. Australian Geological Survey Organisation; Australia.Fil: Skirrow, Roger G. Australian Geological Survey Organisation; Australia.Cubrimiento parcial de la hoja.The Cosquin 1:100.000 Sheet area lies within the Córdoba Province, between 31o00’-31o20’S and 64o00’-64o30’W. The area is part of the Córdoba (3163-III)1:250 000 sheet area. The region includes the central northern part of the Sierra Chica, one of several north-trending mountain ranges which traverse the northern part of the Córdoba Province. The Sierra Chica is drained by the easterly flowing Ríos La Granja, Ascochinga, and Santa Sabina. Access to the region, from Córdoba city, is via El Manzano and Ruta Provincial 9 in the east. An unsealed road traverses the eastern flank of the Sierra Chica from El Manzano to La Cumbre (Jesús María sheet area)

The mediated innovation model: a framework for researching media influence in language change

Linguistic innovations that arise contemporaneously in highly distant locations, such as quotative be like, have been termed ‘global linguistic variants’. This is not necessarily to suggest fully global usage, but to invoke more general themes of globalisation vis-à-vis space and time. This research area has grown steadily in the last twenty years, and by asserting a role for mass media, researchers have departed intrepidly from sociolinguistic convention. Yet they have largely relied on quite conventional sociolinguistic methodologies, only inferring media influence post hoc. This methodological conservatism has been overcome recently, but uncertainty remains about the overall shape of the new epistemological landscape. In this paper, I review existing research on global variants, and propose an epistemological model for researching media influence in language change: the mediated innovation model. I also analyse the way arguments are constructed in existing research, including the use of rhetorical devices to plug empirical gaps – a worthy sociolinguistic topic in its own right

Bond Graph Modelling of Physical Systems

This thesis describes new methods for creating and analysing bond graph models of continuous physical systems. The concept of a core model representation is central to this research, since it is shown that the need to generate and maintain a range of models discourages the widespread use of modelling. Mathematical models appropriate to specific applications are not, in general, sufficiently comprehensive to be used as the core model representation, whereas all the models of interest for analysis and simulation may be derived from a bond graph model. Hierarchical model representations are shown to be an aid to reducing complexity, and thus the bond graph methodologies, which are developed, fully support hierarchical models. A new bond graph algorithm for identifying and solving algebraic loops is described, and extended to provide a steady-state model of the system. The new algorithm is shown to systematically create a differential algebraic equation (DAE) model of the system. Bond graph causality is shown to be a powerful analytical concept, but classical causal propagation algorithms have limitations which are discussed. These limitations are overcome by a novel computable causality approach, and its bicausal bond graph representation. The computable causality algorithm is used for resolving algebraic loops, and handling of modulations. The new concepts of unilateral bonds and bicausal bond graphs generalise the classical causality notation to permit physically unrealisable (but computationally useful) bond graph causalities. The computable causality algorithm provides a systematic method for deriving generalised state equation (or DAE) mathematical models from bicausal bond graphs. Practical applications of the new bond graph techniques are demonstrated through the analysis of four real physical systems as case studies. The implementation and operation of a DOS-based tool which uses bond graphs as the core model representation is described

The resource allocation consequences of the new NHS needs formula

The NHS Executive has recently implemented modifications to the weighted capitation formula for distributing Hospital and Community Health Service funds to health authorities in England. A major contribution to the changes was an analysis of the relative needs of geographical areas undertaken by a team of researchers from the University of York. That work investigated the link between social and economic circumstances and the use of NHS inpatient facilities, and resulted in the development of separate needs indices for acute and psychiatric inpatient services. This report first documents the resource allocation consequences of each of these indices, and finds that the acute index is slightly more redistributive than the previous formula, and that the psychiatric index is very much more redistributive, in particular redirecting resources into the inner cities. In implementing the work, the Department of Health had to make a judgement about which needs index to use for distributing funds not relating to inpatient use, In the event, they have chosen to allocate 64% of the total budget according to the acute index, 12% according to the psychiatric index, and 24% according to no needs index. The report notes that the use of no needs weighting for such a large block of services, which includes community and mental handicap services, can be challenged. It illustrates the importance of the issue by comparing the Department’s preferred formula with an alternative, in which the 24% is allocated using the York acute index. It is found that this option would redirect amounts of up to 5% away from the home counties towards the inner cities. While not necessarily advocating this change, the report argues that the large sums involved highlight the urgent necessity for research on the relative need for health care in non-inpatient services.RAWP, HCHS funds, SMR

Does training on inhibitory tasks influence alcohol consumption and attitudes?

Response inhibition - the suppression of a prepotent or ongoing action - is an executive function central to the regulation of behaviour. Response inhibition can be assessed in the laboratory using the Go/No-go or Stop-Signal tasks which both assess the capacity to withhold an inappropriate response. In the Go/No-go task, participants are required to respond rapidly to Go stimuli but to withhold that response upon No-go stimuli. In the Stop-Signal task, participants are required to respond to Go stimuli but to withhold the response when an auditory stop signal occurs subsequent to the Go stimulus