Macquarie University

About: Macquarie University is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 14075 authors who have published 47673 publications receiving 1416184 citations. The organization is also known as: Macquarie uni.

Formal Proofs for the Security of Signcryption

Abstract: Signcryption is an asymmetric cryptographic method that provides simultaneously both message confidentiality and unforgeability at a low computational and communication overhead. In this paper we propose realistic security models for signcryption, which give the attacker power to choose both messages/signcryptexts as well as recipient/sender public keys when accessing the signcryption/unsigncryption oracles of attacked entities. We then show that Zheng's original signcryption scheme is secure in our confidentiality model relative to the Gap Diffie-Hellman problem and is secure in our unforgeability model relative to a Gap version of the discrete logarithm problem. All these results are shown in the random oracle model.

A framework for benchmarking land models

Abstract: Land models, which have been developed by the modeling community in the past few decades to predict fu- ture states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosys- tem responses and feedback to climate change. Benchmark- ing is an emerging procedure to measure performance of models against a set of defined standards. This paper pro- poses a benchmarking framework for evaluation of land model performances and, meanwhile, highlights major chal- lenges at this infant stage of benchmark analysis. The frame- work includes (1) targeted aspects of model performance

Prioritizing Key Resilience Indicators to Support Coral Reef Management in a Changing Climate

Abstract: Managing coral reefs for resilience to climate change is a popular concept but has been difficult to implement because the empirical scientific evidence has either not been evaluated or is sometimes unsupportive of theory, which leads to uncertainty when considering methods and identifying priority reefs. We asked experts and reviewed the scientific literature for guidance on the multiple physical and biological factors that affect the ability of coral reefs to resist and recover from climate disturbance. Eleven key factors to inform decisions based on scaling scientific evidence and the achievability of quantifying the factors were identified. Factors important to resistance and recovery, which are important components of resilience, were not strongly related, and should be assessed independently. The abundance of resistant (heat-tolerant) coral species and past temperature variability were perceived to provide the greatest resistance to climate change, while coral recruitment rates, and macroalgae abundance were most influential in the recovery process. Based on the 11 key factors, we tested an evidence-based framework for climate change resilience in an Indonesian marine protected area. The results suggest our evidence-weighted framework improved upon existing un-weighted methods in terms of characterizing resilience and distinguishing priority sites. The evaluation supports the concept that, despite high ecological complexity, relatively few strong variables can be important in influencing ecosystem dynamics. This is the first rigorous assessment of factors promoting coral reef resilience based on their perceived importance, empirical evidence, and feasibility of measurement. There were few differences between scientists' perceptions of factor importance and the scientific evidence found in journal publications but more before and after impact studies will be required to fully test the validity of all the factors. The methods here will increase the feasibility and defensibility of including key resilience metrics in evaluations of coral reefs, as well as reduce costs. Adaptation, marine protected areas, priority setting, resistance, recovery.

A Systematic Review and Meta-Analysis of Magnetic Resonance Imaging Measurement of Structural Volumes in Posttraumatic Stress Disorder

Abstract: Posttraumatic stress disorder (PTSD) is a debilitating condition associated with mild to moderate cognitive impairment and with a prevalence rate of up to 22% in veterans This systematic review and quantitative meta-analysis explore volumetric differences of three key structural brain regions (hippocampus, amygdala and anterior cingulate cortex (ACC)), all of which have been implicated in dysfunction of both salience network (SN) and default mode network (DMN) in PTSD sufferers A literature search was conducted in Embase, Medline, PubMed and PsycINFO in May 2013 Fifty-nine volumetric analyses from 44 articles were examined and included (36 hippocampus, 14 amygdala and nine ACC) with n=846 PTSD participants, n=520 healthy controls (HCs) and n=624 traumatised controls (TCs) Nine statistical tests were performed for each of the three regions of interest (ROIs), measuring volume differences in PTSD subjects, healthy and traumatised controls Hippocampal volume was reduced in subjects with PTSD, with a greater reduction in the left hippocampus A medium effect size reduction was found in bilateral amygdala volume when compared with findings in healthy controls; however, no significant differences in amygdala volume between PTSD subjects and trauma-exposed controls were found Significant volume reductions were found bilaterally in the ACC While often well matched with their respective control groups, the samples of PTSD subjects composed from the source studies used in the meta-analyses are limited in their homogeneity The current findings of reduced hippocampal volume in subjects with PTSD are consistent with the existing literature Amygdala volumes did not show significant reductions in PTSD subjects when compared with volumes in trauma-exposed controls-congruous with reported symptoms of hypervigilance and increased propensity in acquisition of conditioned fear memories-but a significant reduction was found in the combined left and right hemisphere volume analysis when compared with healthy controls Bilateral volume reductions in the ACC may underpin the attentional deficits and inabilities to modulate emotions that are characteristically associated with PTSD patients Language: en