"Fat Tails and Asymmetry in Financial Volatility Models"

Although the GARCH model has been quite successful in capturing important empirical aspects of financial data, particularly for the symmetric effects of volatility, it has had far less success in capturing the effects of extreme observations, outliers and skewness in returns. This paper examines the GARCH model under various non-normal error distributions in order to evaluate skewness and leptokurtosis. The empirical results show that GARCH models estimated using asymmetric leptokurtic distributions are superior to their counterparts estimated under normality, in terms of: (i) capturing skewness and leptokurtosis; (ii) the maximized log-likelihood values; and (iii) isolating the ARCH and GARCH parameter estimates from the adverse effects of outliers. Overall, the flexible asymmetric Student-t distribution performs best in terms of capturing the non-normal aspects of the data.

Did the goodwill accounting standard impose material economic consequences on Australian acquirers?

This research explores the empirical association between takeover bid premium and acquired (purchased) goodwill, and tests whether the strength of the association changes after the passage of approved accounting standard AASB 1013 in Australia in 1988. AASB 1013 mandated capitalization and amortization of acquired goodwill to the income statement over a maximum period of 20 years. We use regressions to assess how the association between bid premium and acquired goodwill varies in the pre-AASB and post-AASB 1013 periods after controlling for confounding factors. Our results show that reducing the variety of accounting policy options available to bidder management after an acquisition results in a systematic reduction in the strength of the association between premium and goodwill

Impacts of climate change on public health in Australia

Provides information, opinions and recommendations relevant to assessing the potential impacts of climate change on public health in Australia, as well as guidelines for decision-making in responding to these impacts. It aims to: draw attention to the potential impacts of climate change on health in Australia; discuss the policies and issues related to the impacts of climate change on health; present prioritised recommendations to decision-makers on policies and practices which may assist mitigation of and adaptation to the most serious of the identified impacts; provide guidance which will assist appropriate people and agencies to allocate resources to the highest priority problems; and provide a comprehensive list of references which provide reliable evidence about the potential impacts of climate change on health in Australia. The immediate and longer-term impacts of climate change have the potential to affect Australian health and social environments seriously, and as such, demand and deserve attention by Federal and State Governments and agencies within the Australian public health sector. Policymakers are faced with pressing issues of funding and delivering health services for an ageing society with an ever increasing burden of chronic disease and expectations of access to high-technology, high cost interventions. However, the impacts of future climate change on public health may potentially generate very large healthcare costs if current strategies for healthcare are inadequate. Successful advocacy of new policies and practices by credible and influential groups must use language which can be understood by the people who are to be influenced. This advocacy must be supported by reliable evidence. Climate-related catastrophes (droughts, floods, cyclones, other storms, bush fires) occur frequently in Australia. The demonstrably high variability in the incidence and severity of such phenomena present a challenge to scientists to discover and demonstrate any correlations between the catastrophes and the slow changes of climatic indices due to climate change. Public health organisations must start to develop alternative, more effective, practices to manage the complex issues related to climate change while continuing to implement their traditional primary, secondary and tertiary preventive models. A new approach, based on ecological principles, will be required to navigate through the complex and interrelating health causes. The public health sector must strengthen existing approaches for effective climate change adaptation strategies, including assessing regional health risks to identify vulnerable and resilient populations, collecting enhanced surveillance data and developing monitoring indicators. This approach must be based on: providing sound scientific evidence for predicting the likely outcomes and thus to take preventive or responsive action; and reorienting the public health sector towards greater comprehension and use of ecological understandings and approaches. Recommendations Politicians, health bureaucrats and other interested parties must formulate comprehensive, coherent policies to address the direct and indirect impacts of climate change on public health, including allocation of appropriate financial resources as part of a National Plan for Health in Responding to Climate Change. The National Health and Medical Research Council should be tasked with ensuring coordinated, comprehensive funding to support research into the health impacts of climate change. Research organisations and health institutions must collaborate to develop cost-effective, long-term, longitudinal studies on the impacts of climate change on the physical, biological and social environments that will affect Australian’s public health. Advocates must develop proposals which demonstrate cost savings to government over three to six years, or one or two electoral cycles. Little will be achieved in the current fiscal environment if proposed policies and practices will incur significant new budgetary expenses to governments or their agencies. Managing the impacts of climate change on public health will also involve several other sectors, such as water, planning, building, housing and transport infrastructure. Appropriate institutions should work towards a multi-level, interdisciplinary and integrated response to raise the importance of the impacts of climate change on public health. A comprehensive surveillance system would monitor the inter-relationship of environmental, social and health factors. Observational studies are important to monitor recent and present disease patterns and incidence to inform modelling of future disease patterns. They could also provide baselines for environmental health indicators, which can periodically be monitored and measured in order to inform program evaluation. The public health sector must integrate planned, evidence-based adaptations into existing preventive activities. Useful methodologies might include: a risk assessment approach such as Health Impact Assessment (HIA); an appropriate range of Environmental Health Indicators (EHIs); a “Driving force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework”; and a systematic ecological health framework. The opposite of vulnerability is resilience – our capacity to respond to challenging or new circumstances. The factors which encourage resilience needs to be better understood. The public health sector must communicate concepts of risk, and develop strategies to encourage greater resilience. To understand how we can minimise vulnerability of individuals and communities to climate change we must identify those populations which are most at risk, including those for whom climate change will act as a stress multiplier for existing public health problems. The health sector must communicate climate change as a human health issue rather than just an “environmental problem”. The focus should be on effective, realistic and sustainable solutions rather than problems characterised as bleak and unresolvable

Facilitering van de gewelddadige jihad

Summary in English Muslims who do not actively contribute to the violent jihad but who tacitly or openly sympathize with it are vital to the persistence of this kind of terrorism according to some terrorist fighters and scholars. We used interviews and public information in order to examine the accuracy of this claim. The analysis points out that sympathizers are indeed crucial to some preparative terrorist activities, yet not to other. Muslim extremists depend less on sympathizers for making foreign journeys, generating revenues, and communication then they do for recruiting and sponsoring. This conclusion implies that receding of sympathy for the violent jihad will not automatically reduce it

Numerical modelling of the filling of formworks with self-compacting concrete

This paper describes the numerical modelling of the flow of self-compacting concrete (SCC) in column and wall formworks during the filling process. It is subdivided in four main parts. In the first part, the rheological properties of SCC and the theory regarding the pressure exerted by the SCC on the formworks are shortly described. In the second part, the formwork filling tests, that have been carried out at the Magnel Laboratory for Concrete Research of the Ghent University, are presented. The general layout of the tests and the measurement set-up are clearly described. In the third part, the numerical modelling of the flow of SCC using a commercially available solver is explained as well as the obtained results from the CFD simulations. Finally in the last part, a comparison is made between the measurements and the simulation results. The formwork pressures are hydrostatic for SCC pumped from the base of the formworks

Modeling Outliers and Extreme Observations for ARMA-GARCH Processes

No abstract.

Psychosocial and environmental correlates of walking, cycling, public transport and passive transport to various destinations in Flemish older adolescents

BACKGROUND: Active transport is a convenient way to incorporate physical activity in adolescents' daily life. The present study aimed to investigate which psychosocial and environmental factors are associated with walking, cycling, public transport (train, tram, bus, metro) and passive transport (car, motorcycle, moped) over short distances (maximum eight kilometres) among older adolescents (17-18 years), to school and to other destinations. METHODS: 562 older adolescents completed an online questionnaire assessing socio-demographic variables, psychosocial variables, environmental variables and transport to school/other destinations. Zero-inflated negative binomial regression models were performed. RESULTS: More social modelling and a higher residential density were positively associated with walking to school and walking to other destinations, respectively. Regarding cycling, higher self-efficacy and a higher social norm were positively associated with cycling to school and to other destinations. Regarding public transport, a higher social norm, more social modelling of siblings and/or friends, more social support and a higher land use mix access were positively related to public transport to school and to other destinations, whereas a greater distance to school only related positively to public transport to school. Regarding passive transport, more social support and more perceived benefits were positively associated with passive transport to school and to other destinations. Perceiving less walking and cycling facilities at school was positively related to passive transport to school only, and more social modelling was positively related to passive transport to other destinations. CONCLUSIONS: Overall, psychosocial variables seemed to be more important than environmental variables across the four transport modes. Social norm, social modelling and social support were the most consistent psychosocial factors which indicates that it is important to target both older adolescents and their social environment in interventions promoting active transport. Walking or cycling together with siblings or friends has the potential to increase social norm, social modelling and social support towards active transport

Validation of the STRIVE model for coupling ecological processes and surface water flow

The 1D model package STRIVE is verified for simulating the interaction between ecological processes and surface water flow. The model is general and can be adapted and further developed according to the research question. The hydraulic module, based on the Saint-Venant equations, is the core part. The presence of macrophytes influences the water quality and the discharge due to the flow resistance of the river, expressed by Manning's coefficient, and allows an ecological description of the river processes. Based on the advection–dispersion equation, water quality parameters are incorporated and modelled. Calculation of the water quantity parameters, coupled with water quality and inherent validation and sensitivity analysis, is the main goal of this research. An important study area is the River Aa near Poederlee (Belgium), a lowland river with a wealth of vegetation growth, where discharge and vegetation measurements are carried out on a regular basis. The developed STRIVE model shows good and accurate calculation results. The work highlights the possibility of STRIVE to model flow processes, water quality aspects and ecological interaction combined and separately. Coupling of discharges, water levels, amount of biomass and tracer values provides a powerful prediction modelling tool for the ecological behaviour of lowland rivers