Correlations, Plasmarons, and Quantum Spectral Function in Bilayer Graphene

We theoretically study the many-body effects of electron electron interaction on the single particle spectral function of doped bilayer graphene. Using random phase approximation, we calculate the real and imaginary part of the self-energy and hence the spectral function. The spectral function near the Fermi surface shows the usual quasiparticle peak, establishing doped bilayer graphene, in contrast to the unstable neutral system, to be a Fermi liquid. Away from the Fermi surface, an additional broad plasmaron peak is visible in the spectral function. From the low energy behaviour of the self-energy we calculate the quasiparticle residue and the effective mass of the quasiparticles as a function of carrier density. We present results for both the on-shell and the off-shell approximation for the quasiparticle renormalization.Comment: 5 pages, 3 figure

A Temporal Logic Based Approach to Multi-Agent Intrusion Detection and Prevention

Collaborative systems research in the last decade have led to the development in several areas ranging from social computing, e-learning systems to management of complex computer networks. Intrusion Detection Systems (IDS) available today have a number of problems that limit their configurability, scalability or efficiency. An important shortcoming is that the existing architectures is built around a single entity that does most of the data collection and analysis. This work introduces a new architecture for intrusion detection and prevention based on multiple autonomous agents working collectively. We adopt a temporal logic approach to signature-based intrusion detection. We specify intrusion patterns as formulas in a monitorable logic called EAGLE. We also incorporate logics of knowledge into the agents. We implement a prototype tool, called MIDTL and use this tool to detect a variety of security attacks in large log-files provided by DARPA

The role of microRNA-194 and microRNA-375 in prostate cancer metastasis

Prostate cancer (PCa) is a major public health problem worldwide. In Australia, it is the most common non-dermatological cancer and second leading cause of cancer related death in men. The risk of being diagnosed with PCa increases with age, and 1 in 6 men are estimated to be affected in their lifetime. Given that Australia has an ageing population, it is projected that the number of men living with PCa will increase from 120,000 to 267,000 by 2017. While significant advances have been made in the treatment of localised, organ-confined prostate tumours, the disease becomes incurable once it has metastasized. Thus, identifying mechanisms that contribute to PCa spread is an urgent requirement. A considerable body of research has demonstrated that aberrant expression of microRNAs (miRs), a class of small non-coding regulatory RNAs, can be an important factor in prostate cancer metastasis. Previous studies in our laboratory identified serum miR-194 and miR-375 as novel markers of disease progression in men with PCa. However, whether these two miRNAs play a direct role in the biology of prostate tumors is unknown. My PhD aimed to assess the role of miR-194 and miR-375 in PCa progression and metastasis. My work demonstrated that miR-194 enhanced pro-metastatic features of PCa cells, including migration, invasion and epithelial mesenchymal transition (EMT), in vitro and also augmented metastasis in vivo. I identified and validated SOCS2 as a novel, direct and biologically relevant target of miR-194. My research supports a model whereby targeting of SOCS2 by miR-194 leads to activation of the JAK2/STAT3 and ERK1/2 signalling pathways, two key pathways involved in promoting PCa metastasis. Further, I have demonstrated that miR-194 is regulated by GATA2, an oncogenic transcription factor in PCa. On the other hand, my work demonstrated that miR-375 is a potent tumour suppressor miRNA, as it can inhibit EMT, invasion and growth of prostate cancer cells. I identified YAP1, a transcriptional coactivator and a potent oncogene, as a direct and biological relevant target of miR-375. Additionally, I demonstrated that miR-375 was under the direct transcriptional control of EMT-promoting factor, ZEB1. Collectively, these findings provide greater understanding of the role of miR-194 and miR-375 in prostate cancer metastasis. This information could inform the potential application of these miRNAs as biomarkers, and could lead to efforts to target miR-194 to prevent prostate cancer metastasis.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Medicine, 2016