Botev Z.I.,University of New South Wales |
Vaisman S.,University of Queenland |
Rubinstein R.Y.,Technion - Israel Institute of Technology |
L'Ecuyer P.,University of Montreal
Proceedings - Winter Simulation Conference | Year: 2015
We consider the problem of estimating the unreliability of a stochastic flow network, defined as the probability that the maximum flow value from a source node to a terminal node in a directed network with stochastic link capacities, is less than a specified demand level. The link capacities are assumed to be continuous random variables with a known joint distribution. We are interested in the situation where the unreliability is very small, in which case a crude Monte Carlo is not viable. We show how a Monte Carlo splitting algorithm can be adapted to handle this problem effectively. © 2014 IEEE.
Cui L.,Capital Normal University |
Shi G.,Capital Normal University |
Oei T.P.S.,University of Queenland
Stress and Health | Year: 2013
The objective of the present study is to test the validity of the integrated cognitive model of depression proposed by Kwon and Oei (1994) with a Chinese adolescent sample. A two-wave panel design was used. We hypothesized that the interaction between dysfunctional attitudes measured at time 1 and adolescents' negative life events experienced between times 1 and 2 would predict changes in the frequency of automatic thoughts between times 1 and 2. We further hypothesized that changes in the frequency of automatic thoughts would, in turn, predict changes in the severity of depressive symptoms. Participants were 329 Chinese adolescents. As a comparison, we tested three other competing models: linear mediation, alternative aetiologies and symptom models. All participants completed the Adolescent Self-Rating Life Events Checklist, Dysfunctional Attitudes Scale, Automatic Thoughts Questionnaire and Center for Epidemiological Studies Depression Scale on two occasions-5 months apart. Path analysis was used to test all models. Results of the path analysis indicated that the integrated cognitive model showed an adequate fit for the Chinese adolescent data. During phases of increased depression, dysfunctional attitudes were common cognitive moderators of depression, whereas automatic thoughts were specific cognitive mediators of depression. Copyright © 2013 John Wiley & Sons, Ltd.
Ransan-Cooper H.,Australian National University |
Farbotko C.,CSIRO |
McNamara K.E.,University of Queenland |
Thornton F.,University of Canberra |
Chevalier E.,University of Sydney
Global Environmental Change | Year: 2015
This paper presents an evolving typology of frames - filters of sense-making - to unpack how actors are interpreting and responding to the issue of environmental migration. We use frame analysis to draw attention to how a variety of actors define the boundaries of environmental migration, both intentionally and unintentionally, and how this generates interpretations and directions for policy action. In particular, we identify and discuss four unique framings of the environmental migrant notable in popular policy and academic debate: victims, security threats, adaptive agents and political subjects. Although not always consistently deployed by the same actors, and often hybridised, we argue that the four framings highlight different political, ideological and practical beliefs associated with particular interests and normative assumptions. The paper uses a qualitative, interpretive approach suited to understanding over-arching, macrocultural frames. We explore how key actors produce, communicate and legitimise each framing, discuss the ramifications of such and highlight major apparent critiques. We conclude that despite the four framings identified by us, scope of debate concerning environmental migration is marked by continued dynamism. Within this context, the frame perspective may stimulate greater reflexivity about assumptions and blindspots about this complex phenomenon to ground debate and action, in an arena that often relies on high-level and abstract language. © 2015 Elsevier Ltd.
Zhang X.,University of Newcastle |
Krabbenhoft K.,University of Newcastle |
Pedroso D.M.,University of Queenland |
Lyamin A.V.,University of Newcastle |
And 3 more authors.
Computers and Geotechnics | Year: 2013
A version of the Particle Finite Element Method applicable to geomechanics applications is presented. A simple rigid-plastic material model is adopted and the governing equations are cast in terms of a variational principle which facilitates a straightforward solution via mathematical programming techniques. In addition, frictional contact between rigid and deformable solids is accounted for using an approach previously developed for discrete element simulations. The capabilities of the scheme is demonstrated on a range of quasi-static and dynamic problems involving very large deformations. © 2013 Elsevier Ltd.
Sunagar K.,University of Porto |
Fry B.G.,University of Queensland |
Fry B.G.,University of Queenland |
Jackson T.N.W.,University of Queensland |
And 12 more authors.
PLoS ONE | Year: 2013
Neurotrophins are a diverse class of structurally related proteins, essential for neuronal development, survival, plasticity and regeneration. They are characterized by major family members, such as the nerve growth factors (NGF), brain-derived neurotrophic factors (BDNF) and neurotrophin-3 (NT-3), which have been demonstrated here to lack coding sequence variations and follow the regime of negative selection, highlighting their extremely important conserved role in vertebrate homeostasis. However, in stark contrast, venom NGF secreted as part of the chemical arsenal of the venomous advanced snake family Elapidae (and to a lesser extent Viperidae) have characteristics consistent with the typical accelerated molecular evolution of venom components. This includes a rapid rate of diversification under the significant influence of positive-selection, with the majority of positively-selected sites found in the secreted β-polypeptide chain (74%) and on the molecular surface of the protein (92%), while the core structural and functional residues remain highly constrained. Such focal mutagenesis generates active residues on the toxin molecular surface, which are capable of interacting with novel biological targets in prey to induce a myriad of pharmacological effects. We propose that caenophidian NGFs could participate in prey-envenoming by causing a massive release of chemical mediators from mast cells to mount inflammatory reactions and increase vascular permeability, thereby aiding the spread of other toxins and/or by acting as proapoptotic factors. Despite their presence in reptilian venom having been known for over 60 years, this is the first evidence that venom-secreted NGF follows the molecular evolutionary pattern of other venom components, and thus likely participates in prey-envenomation. © 2013 Kartik Sunagar.