Fitting MA(q) models in the closed invertible region

The use of reparameterization in the maximization of the likelihood function of the MA(q) model is discussed. A general method for testing for the presence of a parameter estimate on the boundary of an MA(q) model is presented. This test is illustrated with a brief simulation experiment for the MA(q) for q=1,2,3,4 in which it is shown that the probability of an estimate being on the boundary increases with q.Admissible region for the autoregressive-moving average time series ARMA model reparameterization Numerical maximum likelihood estimation

Adsorptive properties of microporous carbons: primary and secondary micropore filling

A study has been made of the mechanisms of micropore filling with particular reference to the adsorptive properties of two samples of activated charcoal cloth, having predominantly narrow slit-shaped pores, and a coke-based carbon, having a wider distribution of micropores. Nitrogen adsorption data at 77 K have been analysed by use of the αs-method and the Dubinin-Radushkevich equation. Integral heats of adsorption for a range of organic adsorptives have been derived from heat of immersion data in conjunction with physisorption data. The findings support the view that there are two distinctive mechanisms of micropore filling: (a) a primary process, which takes place at very low p/p° and involves enhanced adsorbent-adsorbate interactions and (b) a secondary process, which leads to a more gradual approach to the plateau of a Type I isotherm and is the result of co-operative effects associated with the filling of wider micropores (the supermicropores of Dubinin)

Supplementary Material for: SPARKLE (Subtypes of Ischaemic Stroke Classification System), Incorporating Measurement of Carotid Plaque Burden: A New Validated Tool for the Classification of Ischemic Stroke Subtypes

<b><i>Background:</i></b> Previous classification systems of acute ischemic stroke (Causative Classification System, CCS, of acute ischemic stroke, Trial of Org 10172 in Acute Stroke Treatment, TOAST) established the diagnosis of large artery disease (LAD) based on the presence or absence of carotid stenosis. However, carotid plaque burden is a stronger predictor of cardiovascular risk than stenosis. Our objective was to update definitions of ischemic stroke subtypes to improve the detection of LAD and to assess the validity and reliability of a new classification system: SPARKLE (Subtypes of Ischaemic Stroke Classification System). <b><i>Methods:</i></b> In a retrospective review of clinical research data, we compared three stroke subtype classifications: CCS, TOAST and SPARKLE. We analyzed a random sample of 275 patients presenting with minor stroke or transient ischemic attack (TIA) in an Urgent TIA Clinic in London, Ont., Canada, between 2002 and 2012. <b><i>Results:</i></b> There was substantial overall agreement between SPARKLE and CCS (κ = 0.75), with significant differences in the rate of detection of LAD, cardioembolic and undetermined causes of stroke or TIA. The inter-rater reliability of SPARKLE was substantial (κ = 0.76) and the intra-rater reliability was excellent (κ = 0.91). <b><i>Conclusion:</i></b> SPARKLE is a valid and reliable classification system, providing advantages compared to CCS and TOAST. The incorporation of plaque burden into the classification of LAD increases the proportion of cases attributable to LAD and reduces the proportion classified as being of 'undetermined' etiology