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Thursday 11th September, 2008 at 8pm
Speaker: Prof. Rachel Webster
Dept. of Physics, University of Melbourne
TOPIC: The First Stars in the Universe
Prof. Webster discussed a brief history of the universe; a particular period in the evolution of the universe called the Epoch of Re-ionisation also known as 'the dark ages of the universe' as it is difficult for optical light to travel from sources at this time to reach us today. Finally she discussed a new radio telescope which is being built in outback Western Australia, which we hope will detect the epoch of Re-ionisation for the first time.
The key physical characteristics of our universe are;
(1) it is expanding,
(2) it started with a very dense hot early phase, and
(3) the universe is homogeneous and isotropic on large scales.
The very earliest time, when we can apply known physics is called the Planck time, and occurred 10-43 secs after the 'Big Bang'. The Big Bang is the strange name give to the beginning of our universe, but has little physical meaning. Prior to the Planck time, the application of quantum mechanics and gravitational physics to the physical universe doesn't really make sense. A little later on, there was a very small asymmetry between the number of protons and anti-protons – one part in a million. After they annihilated, a universe filled only with matter remained. During this time, the universe was also filled with photons of light, and the photons were tightly coupled to the electrons. The universe continued to expand and cool, eventually forming mostly Hydrogen and Helium nuclei. When it was about 380,000 years old, it had cooled enough for protons and electrons to form neutral Hydrogen atoms. Mostly importantly, at this time, the universe became transparent to photons. Today we see the redshifted blackbody light from this time as the Cosmic Microwave Background.
After this time, the first stars formed as denser regions collapsed under gravity. We think that these first stars may have been very massive and lived short lives. We know that the Ultra-Violet photons from these stars re-ionised the neutral Hydrogen, allowing us to see the first sources of light at these great distances. This is called the Epoch of Re-ionisation.
We have some evidence from the spectra of high redshift quasars, that the Epoch of Re-ionisation occurred a little earlier than a redshift of six. We know that when the first stars started shining that they will have warmed and ionised the Hydrogen surrounding them. The warmed Hydrogen will have
emitted radio photons at 21cm. These photons will travel unperturbed through the universe, and will be detectable today. Astrophysicists have calculated the signatures we expect to see in 21cm emission, and it is expected that these signature could be detected with a suitable telescope on Earth.
However, the frequency which we would be required to observe in, is near the FM radio band. This is not a radio frequency in which astronomers have been actively observing for the past 30 or so years. In order to detect this emission, we need to build a new low frequency radio telescope. The very best location on Earth is in Western Australia, far from concentrations of people. A new collaboration of Australian universities, with MIT and Harvard from the US and the Raman Research Institute from India, has funding to develop and build such a telescope. The primary science case for the telescope will be the detection of the 21cm radiation from the very first stars, or the end of the Epoch of Re-ionisation. However the telescope will also make significant contributions to our understanding of space weather, and in particular the passage of coronal mass ejections from the Sun to Earth. This will have implications for satellites, communications, power grids and so on.
We have already shown that the site is pristine, and is not contaminated by regular human activities. We have built and operated a test array with three tiles, and are currently building an array of 32 tiles. We expect to commence an array of over 500 tiles in the middle of 2009.
This is a fundamentally new experiment to explore the time when the first stars in our universe were being born. The low frequency telescope should be operational by the middle of 2010 on the site which will be Australia's candidate site to host the Square Kilometre Array. The SKA is the next generation international radio telescope, expected to cost in excess of a billion dollars.
Thursday 14th August, 2008 at 7pm
Speaker: Prof. Paul Zimmet AO FTSE
Professor Director & Head,
International Diabetes Inst.
TOPIC: The Global Diabesity Tsunami – Tracking and Tackling the Epidemic
A 2005 World Health Organization (WHO) report "Preventing Chronic Diseases: A Vital Investment" shows that non-communicable diseases (NCDs) dominated by diabetes and obesity are causing double the deaths that are caused by infectious diseases, maternal/perinatal conditions, and malnutrition combined. The report states that without action, 388 million people globally will die from chronic diseases like diabetes and heart disease in the next decade. It is against this background that we are facing a global threat from the spectacular rise in the global prevalence of type 2 diabetes and obesity and their consequences.
In terms of diabetes, the number of cases has reached pandemic proportions and will continue to increase sharply. The Melbourne-based International Diabetes Institute has predicted that the number of people with diabetes will almost double within just one generation, from the present 250 million to 380 million in 2025. The linkage between obesity and type 2 diabetes is very strong, in fact, so strong that the term diabesity is being used frequently to better describe the current twin epidemic.
Unfortunately, most nations are poorly prepared to tackle this twin epidemic effectively. Governments remain largely unaware of, or are complacent about, the existing magnitude of the NCD challenge. More important is the fact that they ignore the future increases in obesity and diabetes and their serious complications such as cardiovascular disease (CVD). Failure to act now on the direct costs of healthcare and the indirect costs from loss of productivity and from premature morbidity and mortality is very likely to cripple the health budgets of many nations, both developing and developed.
With this major international challenge in mind, in May 2005, the International Diabetes Institute, in conjunction with the Monash University Institute of Global Movements and the UK-based Nuffield Trust, in London to assess the impact of globalization on health in both developed and developing countries with respect to NCDs such as CVD, diabetes, and obesity. The NCD burden has now become one of the major threats to human health in the 21st century.
Globalization and World Health: Globalization of the world economy has become a fashionable subject and we are constantly reminded that we are all members of the global village. But this means very little to people in areas subject to natural disasters and in sites of major political tension and poverty.
Research findings have not been translated into improved health outcomes, in particular for obesity and type 2 diabetes which are epidemic in the peoples of many developing nations and in the economically disenfranchised minorities of many developed countries including the United States, Canada, and indeed, our own indigenous community.
Globalization does not apply just to economic change but also to the human diet and lifestyle. So, tragically, the diabesity epidemic is linked to the socioeconomic revolution and its impact on the traditional way of life, including nutritional and physical activity patterns. This means that the solution, that is, the prevention and control of these NCDs, is not entirely in the hands of individuals and the medical community.
The Epidemiological Perspective: From a historical perspective, until the latter part of the 19th century, the main causes of morbidity and mortality in all nations have been epidemics of communicable diseases including typhoid, cholera, smallpox, diphtheria, and influenza. The discovery and availability of antibiotics and vaccines have radically changed the profile of diseases, initially in developed countries and later in many developing countries. Consequently, these improvements in public health have led to dramatic reductions in mortality from infectious diseases. Paradoxically, there has been a remarkable increase in the prevalence of risk factors for NCDs such as type 2 diabetes, CVD, hypertension, and strokes.
The devastating results of Western intrusion into the lives of traditional-living indigenous communities can now be seen from the jungles of Brazil to the remote and idyllic atolls of the Pacific Ocean. Quite apart from the socioeconomic aspect, the health impact is disastrous; there are epidemic diabetes rates in most Pacific Island populations and type 2 diabetes now affects up to 30% of adults. Before World War II, it was virtually unknown. This picture is mirrored in disadvantaged communities in developed nations, e.g. Native Americans, African Americans, and Mexican Americans in the U.S., Native Canadians, Indigenous Australians and Torres Strait islanders, and in the Maori community in New Zealand.
The resources applied to meet this challenge are miniscule; for example, the WHO budget is less than 5%. Globally, type 2 diabetes accounts for more than 90% of all cases of diabetes. Not only is the prevalence of type 2 diabetes increasing, but the age of onset is becoming younger with an increasing number of children and adolescents now being diagnosed.
Nevertheless, the prevention and control of type 2 diabetes and the other major NCDs can be cost- and health-effective through an integrated lifestyle and behavioural approach to NCD disease prevention and control.
The View from London: The areas covered at the London globalization and health meeting at the Nuffield Trust included active intervention at governmental, and supragovernmental, levels was essential, and this meant governments ceasing to take what had often been the traditional stance that these matters had to be left to individual choice.
There is an immediate need for the diabetes, obesity, and cardiovascular and public health communities to lobby and mobilize politicians, other international and regional agencies such as the United Nations Development Programme (UNDP), the United Nations Children's Fund (UNICEF), WHO, and the World Bank to address the socioeconomic, behavioral, nutritional, and public health issues that have led to the NCD epidemic. A multidisciplinary approach by governments that involves multiple ministries such as health, finance, education, sports, and agriculture can all contribute to a reversal of the underlying socioeconomic causes of the problem. These diseases will cause havoc and the socioeconomic cost through family disruption, loss to the work force, and premature mortality coupled with the public health burden on primary, secondary, and tertiary health care services in poor nations is already extracting a high economic toll.
Conclusions: The world community has been very slow to react to the problem of the NCD epidemic and the urgent need to address the prevention issues. This has been further complicated by the recent reemergence of devastating communicable diseases mentioned earlier. The NCD explosion will not be prevented by diet and exercise alone! We need to see new imaginative strategies and major and dramatic changes in the socioeconomic and cultural status of people in developing countries and disadvantaged and minority groups in developed nations.
Global concern about our ecosystem culminated with an international talk-fest, The United Nations Conference on Environment and Development in Rio de Janeiro in 1992. This resulted in The Rio Declaration on Environment and Development. The conference participants were particularly conscious of the much-feared impact of global warming on the future of humanity. There is now an urgent need for a similar international meeting (e.g. a Kyoto Health) to consider the impact of globalization on health along the lines of meetings that have looked at the impact of globalization on the environment.
Thursday 10th July, 2008 at 7pm
Speaker: Dr. Geoff Lacey
University of Melbourne
TOPIC: Ecological History of the Middle Yarra
In 1840, at the beginning of European settlement in the Melbourne area, the author Rolf Boldrewood described the surroundings of the Yarra at Heidelberg. He spoke of heavily timbered flats, with trees of unusual size and straightness. He described the lagoons on the east side of the river at Bulleen as being surrounded by dense thickets, difficult to penetrate, and full of waterbirds.
However, at around the same time, John Hunter Kerr said the country 'presented an ever-varying succession of lightly-timbered hill and dale, well grassed downs alternated with groups of tall, handsome trees'. How then do we view the contradiction between the two descriptions?
Dr. Lacy's talk examined the question: what was the original ecology of the Yarra, from Heidelberg to Yarra Bend, prior to settlement? He considered the methodology. What can we learn from early writers, artists and photographers? How much information is retained by local historians and naturalists? However, this information is quite limited and it needs to be supported by a reading of the land itself.
The task of reading the land entails the detailed observation of a site in all its aspects, such as the rock, soil, water, plants, animals and human presence. We consider the way these interact and form a whole. We revisit each site again and again, observing how it changes with the seasons and over the years. To discover the history of the land, it is necessary to look in the present site for clues to the past, as well as relating our observations to earlier records and to the reflections and insights of those who have been there before.
Understanding the connections among the landscape elements requires a system or framework. The landscape, in particular that of this study along the valley of the Yarra in Melbourne, is one of clear patterns. It is structured first of all by its geology and geomorphology. Then within this pattern, it is further subdivided by the vegetation communities. At a smaller scale we look at particular sites or local ecosystems. Moreover, there is a whole network of linkages; examples include the effect of geology on the river course and the intimate relationship between rocks, soils, vegetation and animals.
Temporal patterns in the landscape are superimposed on the spatial ones. First there is the annual cycle. And then there are longer term patterns, involving climate, human land use, and changes in groundwater, salinity, and species abundance and distributions.
This project assembles a picture of the original ecology of the area. It considers the pre-European vegetation and the Aboriginal presence in the landscape. It goes on to explore the changes to the river, the flora and fauna since the 1830s, the activities of settlers, the Heidelberg artists, and the achievement of community groups in recovering much of the original character. A remarkable picture emerges of a landscape of meanders, rich wetlands and steep escarpments - a landscape that has retained its wonder while flowing through a metropolis.
In spite of rural and urban developments, the reduced flows and land clearing, the Yarra has shown a remarkable resilience. There is still a richness, both of landforms and of plant and animal species. In places there has been a surprising response to restoration efforts. The Yarra landscape remains one of great beauty.
Thursday 12th June, 2008 at 7pm
Speaker: Dr. Tom Beer
School of Botany,
CSIRO Marine and Atmospheric Research
TOPIC: Natural Hazards and The International Year of Planet Earth
The United Nationals General Assembly declared 2008 to be the International Year of Planet Earth (IYPE). This involves both outreach activities (Australia has issued coins, New Zealand has issued postage stamps) and science activities. 'Hazards – minimising risk, maximising awareness' is one of the ten IYPE science themes.
The International Union of Geodesy and Geophysics (IUGG) is one of the Founding Partners of IYPE. The research activities within IUGG cover landslides, space weather, floods, droughts, storms, bushfires, tsunami, earthquake, volcanic eruptions and avalanche. When such natural hazards strike developing countries then fatalities predominate. In developed countries infrastructure and property losses predominate.
The number of natural hazards that are recorded as disasters have increased, almost exponentially, since 1900 as a result of a combination of better record-keeping and an increase in population numbers. Projections indicate that climate change could further exacerbate the situation.
The natural hazards community views risk as being a combination of hazard occurrence and vulnerability. An alternative view sees risk as involving the variables of likelihoods and consequences, with both variables having a quantitative physical component to them, but also having a social component. By applying ecological systems theory to disasters, it would appear that vulnerability is determined by the individual and the society's resilience, stability, connectivity (links to the outside), organization (internal links), and industry. The Budapest Manifesto on Risk, Science and Sustainability1 sets out steps to deal with these issues.
The IYPE Hazards identified four key research questions such as the role of humankind in increasing geohazards, ways and means of assessing the vulnerability to geohazards of human communities, our current and future ability to monitor, predict and mitigate the impact of geohazards, and the impediments standing in the way of governments making full use of readily available scientific information in planning to reduce risk and vulnerability. These research questions need to be assessed and answered in the context of the Hyogo Framework for Action2 of the UN International Strategy for Disaster Reduction.
Successful research on hazards and disasters requires large-scale international co-operation. The International Union of Geodesy and Geophysics (IUGG) will be working with the International Council of Science (ICSU) to continue the IYPE Hazards work until at least 2011.
1 www.iugg.org/publications/reports/budapest.pdf
2 www.unisdr.org/eng/hfa/hfa.htm
Thursday 8th May, 2008 at 8pm
Speaker: Prof. Mark Burgman
School of Botany,
The University of Melbourne
TOPIC: Eliciting Expert Judgements For Environmental Risk Anaylsis
Expert judgements are a routine and necessary part of risk analysis. Full, detailed model-building and data acquisition are usually too slow, cumbersome and costly for routine application. However, numerous studies have documented that experts may be susceptible to context, framing and cognitive and motivational biases. Experts can be defined by professional standing or performance. Recent advances have shown that perception of risk is filtered by memory, framing, availability, anchoring, 'affect' (intuitive, fast, mostly automatic response to a hazard, linked to experience and emotion), and other heuristics (Slovic et al. 2005).
Overconfidence describes a situation in which the expert's own confidence in their judgment or estimate does not correspond to the accuracy of that judgment or estimate. Research on the performance of nuclear risk engineers, geophysicists, ecologists and other professional groups has shown that most experts are overconfident in their ability to estimate quantities. In recent years, research into elicitation has focused on strategies to account for and overcome cognitive biases (see Plous 1993, Burgman 2005, O'Hagan et al. 2006).
There are several direct and indirect techniques for eliciting uncertainties for quantities, frequencies and probabilities, and for eliciting conceptual models. Direct methods involve simply asking an expert for the desired probabilities or frequencies. There is, however, considerable variation in procedures and formats. Indirect methods infer a judgement about a quantity from a person's behaviour, using contexts such as gambles or pairwise comparisons. Some methods use both qualitative and quantitative information.
Language-based approaches and methods to detect and adjust for expert bias have various strengths and weaknesses, such as the potential for conveying additional meaning which may affect usage and interpretation that is not captured directly in a mapping to a numerical scale. Conceptual models are embedded in formal and informal descriptions of cause-and-effect. Although experts may disagree on the conceptualization of a system or problem, there are surprisingly few tools for systematically resolving such differences.
There is broad scientific consensus on the chief stages of formal elicitation of quantities (Clemen and Reilly 2001). The key theme is that beyond a basic framework, the best approach is to structure the elicitation to suit the decision at hand. General guidelines may avoid the most serious and predictable psychological and motivational pitfalls. The ultimate objective of this research is to create techniques for involving scientific experts that have practical utility for environmental risk analysis.
Thursday 10th April, 2008 at 8pm
Speaker: Prof. Ian Simmonds
Prof. Meteorology, School of Earth Sciences,
University of Melbourne
TOPIC: Dramatic Changes in Liquid and Frozen Water: Climate Change in Australia and the Artic Ocean
Professor Simmonds' lecture focused on changes in the water cycle at opposite ends of the Earth, namely over Australia and in the Arctic. He put these changes in context by commenting that the present levels of greenhouse gases in the atmosphere are 35% higher than they have been for at least one million years. This increase over 'background' levels has occurred over only the last 200 years as a result of Man's consumption of fossil fuels. The best science shows that these changes have caused a global-average surface temperature increase of the best part of 1oC. He made clear than even small changes in these temperatures can have a very dramatic impact on the hydrologic cycle.
In the lecture the changes in precipitation over Australia over the last 60 years were documented. They exhibited decreases in the southern and eastern portion of the continent, with strong increases in the northwest and the far north. When averaged over the entire continent the amount of precipitation has shown an increase. Professor Simmonds explained this complex and apparently conflicting picture of change in terms of atmospheric circulation changes in the presence of a warmer (and therefore more moist) atmosphere. He also drew attention to the impact on precipitation of conditions in the Pacific Ocean (particularly via El Niño), The Indian Ocean, and the Southern Ocean. His causative scenario was consistent with the precipitation changes scenarios of the IPCC for the end of this century. These show enhanced precipitation in equatorial regions, and significantly less in the subtropics.
The second component of Professor Simmonds' lecture focused on changes on frozen sea water (or 'sea ice') in the Arctic. Since 1880 the Arctic region has warmed by almost 2oC (or about twice the global average). In his lecture he showed that over the period for which reliable satellite data on Arctic sea ice coverage is available (since 1979) the amount of sea ice has decreased significantly in each calendar month. Professor Simmonds showed that the reduction has been particularly dramatic in the summer and late-summer months of July, August, September and October, which last year recorded their lowest ever sea ice extent, and September 2007 represented the lowest Arctic ice extent ever registered over the entire satellite era. During that period the 'Northwest Passage' was open for several weeks. In the lecture it was explained how these reductions were associated with the dramatic warming of the Arctic and the input of heat from further south. The extreme nature of the very recent changes in the Arctic have raised the question of whether the Arctic basin is close to a 'tipping point' and its potential for a new climatological state in the high north.
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