Evolution of Threats in the Global Risk Network

With a steadily growing population and rapid advancements in technology, the global economy is increasing in size and complexity. This growth exacerbates global vulnerabilities and may lead to unforeseen consequences such as global pandemics fueled by air travel, cyberspace attacks, and cascading failures caused by the weakest link in a supply chain. Hence, a quantitative understanding of the mechanisms driving global network vulnerabilities is urgently needed. Developing methods for efficiently monitoring evolution of the global economy is essential to such understanding. Each year the World Economic Forum publishes an authoritative report on the state of the global economy and identifies risks that are likely to be active, impactful or contagious. Using a Cascading Alternating Renewal Process approach to model the dynamics of the global risk network, we are able to answer critical questions regarding the evolution of this network. To fully trace the evolution of the network we analyze the asymptotic state of risks (risk levels which would be reached in the long term if the risks were left unabated) given a snapshot in time, this elucidates the various challenges faced by the world community at each point in time. We also investigate the influence exerted by each risk on others. Results presented here are obtained through either quantitative analysis or computational simulations.Comment: 27 pages, 15 figure

Evolution of the Global Risk Network Mean-Field Stability Point

With a steadily growing human population and rapid advancements in technology, the global human network is increasing in size and connection density. This growth exacerbates networked global threats and can lead to unexpected consequences such as global epidemics mediated by air travel, threats in cyberspace, global governance, etc. A quantitative understanding of the mechanisms guiding this global network is necessary for proper operation and maintenance of the global infrastructure. Each year the World Economic Forum publishes an authoritative report on global risks, and applying this data to a CARP model, we answer critical questions such as how the network evolves over time. In the evolution, we compare not the current states of the global risk network at different time points, but its steady state at those points, which would be reached if the risk were left unabated. Looking at the steady states show more drastically the differences in the challenges to the global economy and stability the world community had faced at each point of the time. Finally, we investigate the influence between risks in the global network, using a method successful in distinguishing between correlation and causation. All results presented in the paper were obtained using detailed mathematical analysis with simulations to support our findings.Comment: 11 pages, 5 figures, the 6th International Conference on Complex Networks and Their Application

Tooth Transplantation Using Computer-Aided Rapid Prototyping Model Compared to Conventional Technique (A Pilot Study)

Objective: This research study aimed to compare the efficiency between tooth transplantation using the Computer-aided rapid prototyping model (CARP model) and a conventional tooth transplantation technique. Materials & Methods: Ten patients were enrolled in this study. Patients were randomly divided into 2 groups. Five patients were performed tooth transplantation using the CARP technique (study group) and other five patients were performed antotransplantation using the conventional technique (controlled group). During transplantation, operation time, extra-alveolar time, and attempt of fitting donor tooth to recipient site were evaluated. Moreover, after 3 months post-operation, PDL space, tooth mobility, and pocket depth were examined. Result: During transplantation, the study group consumed lower operating time and extraalveolar time compared to the control group although no statistic significance was found (p = 0.086 and p = 0.05 respectively). In addition, the study group showed significantly fewer attempts to fit the donor tooth to the recipient socket compared to the control group (p = 0.019). After 3 months post-transplantation, average PDL width shows a narrower significant difference in the study group compared to the control group (p = 0.014). Moreover, the study group showed significantly better pocket depth reduction compared to the control group (p = 0.024). No significant difference found in tooth mobility after tooth transplantation in both groups (p = 0.074). Conclusion: CARP technique reduced attempt to fitting donor tooth and improved PDL healing of donor tooth in tooth transplantation compared to conventional technique

Nonindigenous Aquatic Species

Online resource center, maintained by U.S.G.S., provides information, data, links about exotic plants, invertebrates, vertebrates, diseases and parasites. Central repository contains accurate and spatially referenced biogeographic accounts of alien aquatic species. Search for species by state, drainage area, citation in texts; find fact sheets, maps showing occurrence in the U.S. Or, for each taxon, review list of exotic species, find scientific, common name, photo, status; link to facts and distribution map. Educational levels: General public, High school

Exploring the likely effect of the introduction of drug eluting stents on requirements for coronary artery revascularisation procedures in Western Australia: a use of the CHD/CARP Markov Simulation Model

Background: Coronary artery revascularisation procedures (CARPs) include coronary artery bypass graft procedures (CABGs) and the less invasive percutaneous coronary interventions (PCIs) and they are common surgical interventions for coronary heart disease (CHD). The effectiveness of PCIs increased when stents were introduced and there was also a shift towards doing more PCIs and less CABGs, especially in older patients. More recently, PCIs have been further improved by the use of drug-eluting-stents (DES). In this study we used a recently developed CHD/CARP Markov model to explore the likely effect on CARP requirements due to the introduction of DES. Methods: This is achieved by considering the population of Western Australia aged 35 to 79 years at the beginning of 2001 (grouped according to history of CHD and CARPs) as the cohort, calculating the mean population risks for CHD/CARP events over three years 1998 to 2000, and using these population risks and certain modifications of them that incorporate the likely effect of the introduction of DES (in 2002) in the CHD/CARP Markov model to explore difference in total requirements for CABGs and PCIs over the period 2001 to 2010. The anticipated likely effect of DES on probabilities of CARP procedures was based on results of meta-analysis of randomized controlled trials comparing DES stents to ordinary stents and an anticipated further reduction in CABGs and increase in PCIs as was observed when (ordinary) stents were introduced. Results: The simulation results suggest that, over the period 2001 to 2010, the total number of CABGs will decline by up to 19% and the total number of PCIs will increase by up to 6%. Conclusion: The introduction of DES will have greater effect on the requirement of CABGs as compared to that on PCIs

Minimizing the extra-oral time in autogeneous tooth transplantation: use of computer-aided rapid prototyping (CARP) as a duplicate model tooth

OBJECTIVES: The maintenance of the healthy periodontal ligament cells of the root surface of donor tooth and intimate surface contact between the donor tooth and the recipient bone are the key factors for successful tooth transplantation. In order to achieve these purposes, a duplicated donor tooth model can be utilized to reduce the extra-oral time using the computer-aided rapid prototyping (CARP) technique. MATERIALS AND METHODS: Briefly, a three-dimensional digital imaging and communication in medicine (DICOM) image with the real dimensions of the donor tooth was obtained from a computed tomography (CT), and a life-sized resin tooth model was fabricated. Dimensional errors between real tooth, 3D CT image model and CARP model were calculated. And extra-oral time was recorded during the autotransplantation of the teeth. RESULTS: The average extra-oral time was 7 min 25 sec with the range of immediate to 25 min in cases which extra-oral root canal treatments were not performed while it was 9 min 15 sec when extra-oral root canal treatments were performed. The average radiographic distance between the root surface and the alveolar bone was 1.17 mm and 1.35 mm at mesial cervix and apex; they were 0.98 mm and 1.26 mm at the distal cervix and apex. When the dimensional errors between real tooth, 3D CT image model and CARP model were measured in cadavers, the average of absolute error was 0.291 mm between real teeth and CARP model. CONCLUSIONS: These data indicate that CARP may be of value in minimizing the extra-oral time and the gap between the donor tooth and the recipient alveolar bone in tooth transplantation.ope

Adapting a Markov Monte Carlo simulation model for forecasting the number of Coronary Artery Revascularisation Procedures in an era of rapidly changing technology and policy

<p>Abstract</p> <p>Background</p> <p>Treatments for coronary heart disease (CHD) have evolved rapidly over the last 15 years with considerable change in the number and effectiveness of both medical and surgical treatments. This period has seen the rapid development and uptake of statin drugs and coronary artery revascularization procedures (CARPs) that include Coronary Artery Bypass Graft procedures (CABGs) and Percutaneous Coronary Interventions (PCIs). It is difficult in an era of such rapid change to accurately forecast requirements for treatment services such as CARPs. In a previous paper we have described and outlined the use of a Markov Monte Carlo simulation model for analyzing and predicting the requirements for CARPs for the population of Western Australia (Mannan et al, 2007). In this paper, we expand on the use of this model for forecasting CARPs in Western Australia with a focus on the lack of adequate performance of the (standard) model for forecasting CARPs in a period during the mid 1990s when there were considerable changes to CARP technology and implementation policy and an exploration and demonstration of how the standard model may be adapted to achieve better performance.</p> <p>Methods</p> <p>Selected key CARP event model probabilities are modified based on information relating to changes in the effectiveness of CARPs from clinical trial evidence and an awareness of trends in policy and practice of CARPs. These modified model probabilities and the ones obtained by standard methods are used as inputs in our Markov simulation model.</p> <p>Results</p> <p>The projected numbers of CARPs in the population of Western Australia over 1995–99 only improve marginally when modifications to model probabilities are made to incorporate an increase in effectiveness of PCI procedures. However, the projected numbers improve substantially when, in addition, further modifications are incorporated that relate to the increased probability of a PCI procedure and the reduced probability of a CABG procedure stemming from changed CARP preference following the introduction of PCI operations involving stents.</p> <p>Conclusion</p> <p>There is often knowledge and sometimes quantitative evidence of the expected impacts of changes in surgical practice and procedure effectiveness and these may be used to improve forecasts of future requirements for CARPs in a population.</p

Using a Markov simulation model to assess the impact of changing trends in coronary heart disease incidence on requirements for coronary artery revascularization procedures in Western Australia

<p>Abstract</p> <p>Background</p> <p>The population incidence of coronary heart disease (CHD) has been declining in Australia and many other countries. This decline has been due to reduced population levels of risk factors for CHD and improved medical care for those at higher risk of CHD. However, there are signs that there may be a slowing down or even reversal in the decline of CHD incidence due to the 'obesity epidemic' and other factors and this will have implications for the requirements for surgical treatments for those with CHD.</p> <p>Methods</p> <p>Using a validated Markov simulation model applied to the population of Western Australia, different CHD incidence trend scenarios were developed to explore the effect of changing CHD incidence on requirements for coronary artery bypass graft (CABG) and percutaneous coronary interventions (PCI), together known as coronary artery revascularization procedures (CARPs).</p> <p>Results</p> <p>The most dominant component of CHD incidence is the risk of CHD hospital admission for those with no history of CHD and if this risk leveled off and the trends in all other risks continued unchanged, then the projected numbers of CABGs and PCIs are only minimally changed. Further, the changes in the projected numbers remained small even when this risk was increased by 20 percent (although it is an unlikely scenario). However, when the other CHD incidence components that had also been declining, namely, the risk of CABG and that of CHD death for those with no history of CHD, were also projected to level off as these were declining in 1998-2000 and the risk of PCI for those with no history of CHD (which was already increasing) was projected to further increase by 5 percent, it had a substantial effect on the projected numbers of CARPs.</p> <p>Conclusion</p> <p>There needs to be dramatic changes to several CHD incidence components before it has a substantial impact on the projected requirements for CARPs. Continued monitoring of CHD incidence and also the mix of initial presentation of CHD incidence is required in order to understand changes to future CARP requirements.</p