Improved fracture toughness of fire resistant composites through rapid curing

A study on the effect of material and fracture properties of phenolic composites cured with reduced thermal cycle times. These reductions were achieved using various techniques. The work highlights significant reductions in manufacturing times are possible for this group of materials and conveniently can also lead to improved properties.

Out of the frying pan, into the fire : Cantrills Filmnotes as Prestige Machine

This examination of the gaps and ambiguities linked to Cantrills Filmnotes (CF), an Australian publication on experimental film, offers a case study on the production and ownership of Pierre Bourdieu’s 'cultural capital' in film art at the margins, witnessed first-hand. CF emerged at the intersection between the street and the academy, spanning that period from the 70s till its abandonment in 2000 during which, it is argued here, it migrated from the former to the latter. This examination surveils, in retrospect, for whose benefit was the magazine's accumulation of power, status and prestige exercised, in whose service was it exacted? CF’s manifesto-like editorial rhetoric was often directed at perceived shortcomings of those institutions servicing film art in Australia. What is revealed when such a critical eye focuses on the production of Cantrills Filmnotes (CF) itself? CF's cultural production has a further dimension of both taking on and taking place inside a colonial mind-set, a cultural cringe often the subject of editorial commentary, elucidating a practice residing at the geographic margins of a marginal arts practice. The founders and editors of CF, the married couple Corinne and Arthur Cantrill both suffered and benefited from CF’s impact on this international field of art production.

Dynamic regime marginal structural mean models for estimation of optimal dynamic treatment regimes, Part I: main content

Dynamic treatment regimes are set rules for sequential decision making based on patient covariate history. Observational studies are well suited for the investigation of the effects of dynamic treatment regimes because of the variability in treatment decisions found in them. This variability exists because different physicians make different decisions in the face of similar patient histories. In this article we describe an approach to estimate the optimal dynamic treatment regime among a set of enforceable regimes. This set is comprised by regimes defined by simple rules based on a subset of past information. The regimes in the set are indexed by a Euclidean vector. The optimal regime is the one that maximizes the expected counterfactual utility over all regimes in the set. We discuss assumptions under which it is possible to identify the optimal regime from observational longitudinal data. Murphy et al. (2001) developed efficient augmented inverse probability weighted estimators of the expected utility of one fixed regime. Our methods are based on an extension of the marginal structural mean model of Robins (1998, 1999) which incorporate the estimation ideas of Murphy et al. (2001). Our models, which we call dynamic regime marginal structural mean models, are specially suitable for estimating the optimal treatment regime in a moderately small class of enforceable regimes of interest. We consider both parametric and semiparametric dynamic regime marginal structural models. We discuss locally efficient, double-robust estimation of the model parameters and of the index of the optimal treatment regime in the set. In a companion paper in this issue of the journal we provide proofs of the main results.

Dynamic regime marginal structural mean models for estimation of optimal dynamic treatment regimes, Part II: proofs of results

In this companion article to "Dynamic Regime Marginal Structural Mean Models for Estimation of Optimal Dynamic Treatment Regimes, Part I: Main Content" [Orellana, Rotnitzky and Robins (2010), IJB, Vol. 6, Iss. 2, Art. 7] we present (i) proofs of the claims in that paper, (ii) a proposal for the computation of a confidence set for the optimal index when this lies in a finite set, and (iii) an example to aid the interpretation of the positivity assumption.

Does fire influence the landscape-scale distribution of an invasive mesopredator?

Predation and fire shape the structure and function of ecosystems globally. However, studies exploring interactions between these two processes are rare, especially at large spatial scales. This knowledge gap is significant not only for ecological theory, but also in an applied context, because it limits the ability of landscape managers to predict the outcomes of manipulating fire and predators. We examined the influence of fire on the occurrence of an introduced and widespread mesopredator, the red fox (Vulpes vulpes), in semi-arid Australia. We used two extensive and complimentary datasets collected at two spatial scales. At the landscape-scale, we surveyed red foxes using sand-plots within 28 study landscapes - which incorporated variation in the diversity and proportional extent of fire-age classes - located across a 104 000 km2 study area. At the site-scale, we surveyed red foxes using camera traps at 108 sites stratified along a century-long post-fire chronosequence (0-105 years) within a 6630 km2 study area. Red foxes were widespread both at the landscape and site-scale. Fire did not influence fox distribution at either spatial scale, nor did other environmental variables that we measured. Our results show that red foxes exploit a broad range of environmental conditions within semi-arid Australia. The presence of red foxes throughout much of the landscape is likely to have significant implications for native fauna, particularly in recently burnt habitats where reduced cover may increase prey species' predation risk.