The addition of a surfactant at regular time intervals in the mechanical alloying process

The impact of regular additions of a surfactant (ethylene bis-stearamide; EBS) at different time intervals was investigated on the powder characteristics of a biomedical Ti-10Nb-3Mo alloy (wt.%). Ball milling was performed for 10 h on the elemental powders in four series of experiments at two rotation speeds (200 and 300 rpm). The addition of 2 wt.% total EBS at different time intervals during ball milling resulted in noticeable changes in particle size and morphology of the powders. The surfactant addition at shorter time intervals led to the formation of finer particles, a more homogenous powder distribution, a higher powder yield, and a lower contamination content in the final materials. Thermal analysis of the powders after ball milling suggested that differing decomposition rates of the surfactant were responsible for the measured powder particle changes and contamination contents. The results also indicated that the addition of surfactant during ball milling at 200 rpm caused a delay in the alloy formation, whereas ball milling at 300 rpm favored the formation of the titanium alloy.Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved.

Incidence semirings of graphs and visible bases

We consider the incidence semirings of graphs and prove that every incidence semiring has convenient visible bases for its right ideals and for its left ideals, and that these visible bases can be used to determine the weights of all right ideals that have maximum weight and all left ideals that have maximum weight. ©2013 Australian Mathematical Publishing Association Inc..

Neighborhood environmental attributes and adults' maintenance of regular walking

Environmental initiatives to support walking are keys to non-communicable disease prevention, but the relevant evidence comes mainly from cross-sectional studies. We examined neighborhood environmental attributes associated cross-sectionally with walking and those associated prospectively with walking maintenance.

Are the profiles of past-year internet gamblers generalizable to regular internet gamblers?

 Research generally classifies internet gamblers as those who have gambled online at least once in the previous year. This classification system has been criticised on the grounds that it fails to consider the frequency of internet gambling. This study aimed to contrast the demographic, gambling, and psychosocial profiles of regular internet gamblers (at least monthly in the previous year) with those of past-year internet gamblers. Computer-assisted telephone interviews were conducted with 4303 adult respondents from Tasmania, Australia. The findings revealed that 3.3% were past-year internet gamblers and 2.1% were regular internet gamblers. Both past-year and regular internet gambling were significantly associated with several variables (younger age, dependent children, paid employment, higher annual income, higher gambling frequency and expenditure, younger age of first gambling, challenge and positive feelings gambling motives, and positive reinforcement gambling triggers). However, several variables were significantly associated only with past-year internet gambling (male gender, living with partner, number of gambling activities, regulate internal state gambling motives, hazardous alcohol use, cannabis use, and other illicit drug use) or regular internet gambling (higher education). Only gambling for positive feelings was a significant independent predictor of both past-year and regular internet gambling. These findings suggest that the classification of past-year internet gambling that is normally employed in research produces profiles that are not fully generalizable to regular internet gamblers.

Stabilizing high-dimensional prediction models using feature graphs

We investigate feature stability in the context of clinical prognosis derived from high-dimensional electronic medical records. To reduce variance in the selected features that are predictive, we introduce Laplacian-based regularization into a regression model. The Laplacian is derived on a feature graph that captures both the temporal and hierarchic relations between hospital events, diseases, and interventions. Using a cohort of patients with heart failure, we demonstrate better feature stability and goodness-of-fit through feature graph stabilization.

Strongly interactive carnivore species: maintaining and restoring ecosystem function

By emphasizing Australian carnivores as exemplars of flesh-eaters in other parts of the world, this book will be an important reference for researchers, wildlife managers and students worldwide.