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MARSDEN FUND NEWSLETTERNo 26· December 2003
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Professor Murray McEwan (at the back) and |
An instrument designed three decades ago to study chemical reactions in the extreme conditions of outer space is now being developed for use in a range of exciting new applications here on Earth, from diagnosing cancer to detecting leaky buildings.
A team led by Professor Murray McEwan, a physical chemist at Canterbury University, built the instrument, known as a Selective Ion Flow Tube (SIFT) mass spectrometer in the 1970s to study the chemistry of deep space.
Until the 1960s, it had not been recognised that chemical reactions could occur in the apparent emptiness of outer space, but the invention of radio astronomy revealed the existence of gas molecules in space that was previously thought to be completely empty. Researchers realised that if there were molecules present, then chemical reactions must be occurring, and they began to wonder just what these reactions would be like, given the extreme conditions of low temperature and pressure.
As a result, the extremely sensitive SIFT was designed, and used to conduct and measure chemical reactions in the laboratory. In order to analyse a gas sample using the SIFT, ions are first created by microwave activity inside the instrument. A sample of the gas to be analysed is then introduced into the machine, and reacted with these ions. The resulting chemical reactions are studied with the SIFT instrument and from the observations, a model can be constructed of the chemistry that occurs within interstellar clouds.
The results of these experiments could then be compared to radio astronomy data from deep space, to enable more to be learned about the chemical reactions that occur there. The research, for which Professor McEwan has been receiving Marsden funding, has been conducted in collaboration with NASA's Jet Propulsion Laboratory, and continues today.
Recently, however, Professor McEwan and his colleagues began to realise that the SIFT could have applications far beyond those for which it was originally designed. "The machine needed to be extremely sensitive because of the very low pressure conditions in space", said Professor McEwan, "and so we realised that this instrument could be used to measure trace amounts of volatile organic compounds in a sample anywhere on Earth".
Volatile organic compounds are produced in a range of biological processes, and the SIFT has now been modified to detect them. For example, certain diseases such as bowel cancer cause metabolic changes in patients which produce small quantities of volatile compounds. These may be detected using the SIFT. The machine is so sensitive, says Professor McEwan, that a single breath can reveal the presence of disease.
The research team is currently investigating a range of other practical applications of the SIFT. "There's a whole series of things that we're looking at", said Professor McEwan, "all exploratory". For example, he said, it could be used to complement the work of sniffer dogs at airports. "Dogs can't smell a lot of things that our instruments can", he explained. "Unlike people's and dog's noses, this instrument is equally sensitive to any volatile chemical". As a result, the SIFT can be used to find prohibited substances that sniffer dogs would be unable to detect.
The machine could also be used in the building industry. "We can detect fungi where they are growing, for example in leaky buildings", Professor McEwan explained, meaning that leaks can be detected with a high degree of accuracy using the SIFT.
Professor McEwan confessed that one of his main problems was in finding the time to fit all the potential applications into their research programme. In fact, he said, the research is moving so fast that new applications are discovered on a weekly basis.
Commercial uses of the machine are now being explored through the University of Canterbury and private investors. In the future the machine could be used commercially in a range of situations where detection of very small amounts of gas molecules would be useful. As well as its potential applications in medicine, biosecurity and the building industry, it could also be useful in applications as diverse as monitoring of air quality, agriculture, and oil and gas exploration.
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For more information, contact
Professor Murray McEwan Department of Chemistry University of Canterbury Private Bag 4800, Christchurch Tel: (03) 364 2875 Email: m.mcewan@chem.canterbury.ac.nz |
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Biodiversity, the number and variety of species in a particular environment, can vary over time, both on land and in the sea. But many details of the changes in biodiversity that have occurred over geological time are unknown. For example, has biodiversity shown an overall increase over long periods of time, or has it stayed roughly the same? Also, just what factors can control and cause changes in biodiversity?
Funded by a Marsden grant, a team of scientists led by Dr James Crampton and Dr Alan Beu from the Institute of Geological and Nuclear Sciences (GNS) is trying to find answers to these questions by examining the New Zealand marine mollusc record over the last 65 million years. New Zealand has a rich and detailed marine fossil record, in fact the best in the Southern Hemisphere, made all the more valuable by New Zealand's mid-latitude setting adjacent to major ocean currents.
This fossil record has an added advantage of being well documented in a unique and world-renowned database, which includes a wealth of information including species, size, distribution, larval type, habitat, living depth, and feeding habits. This information is allowing the researchers to carry out analyses that are not possible for any other regions of the world. As a result, species that have existed, evolved, or have become extinct over the past tens of millions of years in the New Zealand marine environment can be examined in intricate detail.
However, although the New Zealand marine fossil record is very good, it does contain a number of biases, which can cause problems in analyses if not corrected. As a result of intrinsic and environmental factors, species vary in their ability to produce fossils, meaning that the fossil record does not give a true picture of the full range of species that have existed at any one time. Therefore, before any further studies could be done, a complex and time-consuming computer analysis needed to be developed to correct this bias. A research article on the team's work in this area was published in the 18 July 2003 edition of Science.
Overall, the research aims to answer two questions: What are the patterns of marine biodiversity in New Zealand over time, and what factors control these patterns? The results of their analysis so far indicate that marine diversity in New Zealand increased, and then decreased throughout time. The record shows an approximate doubling of biodiversity for the period between about 30 and 20 million years ago, followed by a marked decline and diversity minimum at about 5 million years ago.
Now that they have determined the overall pattern of historical biodiversity in New Zealand marine molluscs, the researchers aim to develop an explanation for the pattern they have seen. Biodiversity in a particular region is influenced by two sets of opposing forces: the rates of evolution and extinction, and the inward and outward migration of species from the region. These forces are in turn influenced by environmental factors such as temperature and climate, sea level, and changes in major marine currents.
Dr Crampton, Dr Beu and their colleagues plan to investigate in detail the relative rates at which species in the New Zealand marine environment have evolved and become extinct. They will then look at relating these patterns of species evolution and extinction to environmental events such as geographic, oceanographic, and climatic changes in New Zealand throughout time. The project will also involve examining biological characteristics of the organisms that might have controlled how rapidly they evolved, how prone they were to becoming extinct, and how rapidly they could migrate.
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For more information, contact
Dr James Crampton Institute of Geological and Nuclear Sciences P O Box 30 368 Lower Hutt Tel: (04) 570 4887 Email: j.crampton@gns.cri.nz |
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The deadline for preliminary proposals for the next funding round is 12 February 2004. We have kept a similar timetable to that used this year, except that we have changed the day of the week for receiving both preliminary and full proposals from a Friday to a Thursday. Information, application forms and guidelines for the preliminary proposals are available from research offices at institutions, from the Marsden Fund office and the Royal Society website at http://www.rsnz.org/funding/marsden_fund/
Other documents relating to the process, such as information on full proposals, guidelines for panellists and referees, and the list of panellists for 2004 will be on the website from mid December.
There are some changes being introduced for both types of applications in 2004. The main changes are increases to the stipends for postdoctoral fellows and postgraduate students. These are now set at minimum levels, rather than recommended maxima. The value of Fast-Start awards has also been increased, and applicants may now apply for up to $70,000 per year. There are also some layout changes to the forms, so please be sure that you are using the latest version if you are intending to apply in 2004.
The current members of the Marsden Council are: Professor Diana Hill (Chair), Dr Garth Carnaby (Deputy Chair), Professor Robert Ballagh, Professor Peter Bergquist, Professor Sally Casswell, Professor Marston Conder, Professor Charles Daugherty, Mr Jonathan Mane-Wheoki, Professor Pat Sullivan, and Dr David Wratt. Information about each person can be found on the website.
We welcome back Rachel Averill, who has been on parental leave for most of the year, and has recently returned to the team to resume her duties as a research assessor. Unfortunately this has meant that Jason Gush has now left us. We would all like to thank Jason for the tremendous job he has done in the two years he was with us.
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Professor Vince Neall investigating the wetland. |
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| Ngati Mutunga kaumatua, Teru Wharehoka, leads the karakia at the site of the wetland on Jim Phillips' farm. |
Peter Gilberd represented the Marsden Fund and the Royal Society at a hui to mark the completion of a Marsden project on the cultural significance of the Taranaki wetlands. Held at Urenui Marae on 29 November, the purpose of the hui was to report the research findings to all the partners in the project. About 30 people attended the hui, including team members (Harry Allen, Dilys Johns, Caroline Phillips, Janet Wilmshurst, Vince Neall, Tipene O'Brien, and Kelvin Day), members of Ngati Mutunga, and local farmers. The day was an outstanding success, with all participants enjoying themselves and learning much about the history and geology of the area. In their presentations, the researchers emphasised the need to preserve wetlands as a store of information on past land use and occupation. As an example of this, a study of wetland pollens shows that Taranaki was mainly a forest hunting ground until the 17th century; only then did forest clearance occur and permanent settlement take place. The hui participants also visited a wetland on Jim Phillips' farm, near Urenui, where the group examined a white layer of ash in the earth, composed mainly of silica, which represented an eruption from Taupo about 4000 years ago. Janet Wilmshurst showed that you could find very old seeds, preserved in the peat above the ash layer, which carry evidence of gnawing by rats. Janet has a current Fast-Start grant to see what these seeds show about the time of major human settlement in New Zealand (since it is assumed that humans were responsible for the transportation of the Polynesian rat to New Zealand). In retrospect, the "player of the day" was project leader Harry Allen. He made a spectacular leap to safety when a log straddling the wetland gave way and capped it all by daring to use, in heartland New Zealand, "Waltzing Matilda" as a waiata!
The Marsden Fund staff wish you all a very good Christmas break and a satisfying year of research in 2004.
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The limestone of Te Mata Peak:a record of past sea-level changes |
Limestones, well known for their ability to harbour both fossils and oil deposits, were traditionally thought to have formed solely in warm, shallow tropical seas where coral reefs abound. But most of New Zealand's limestone deposits, such as those at Waitomo Caves or Pancake Rocks in Westland, were created in cool sea water, much like that bathing the country today. A Marsden-funded team is now studying in detail the non-tropical limestone ridges in the eastern North Island, using the different layers to decipher sea-level changes and discover more about how loose, shelly carbonate sands are transformed into hard non-tropical limestone.
When Waikato University's Cam Nelson was working on his PhD on the origin of the widespread limestone deposits in the Te Kuiti district in the early 1970s, he was puzzled by the fact that many of the formations he saw lacked most of the features documented by the limestone literature of the day, including an absence of coral reefs. At the same time, reports first began to appear of shelly carbonate deposits forming on modern continental shelves at mid to high latitudes in cool sea water. This led to Professor Nelson showing that most of New Zealand's limestones are fossil analogues of such modern cool-water carbonates, and also emphasised the need to distinguish between tropical and non-tropical carbonates more generally in the rock record, if their true significance was to be understood.
Warm sea water holds plenty of calcium carbonate in solution which, when it precipitates, cements the small pieces of shell together. This converts these fragments into hard tropical limestones. Cool sea water is less carbonate saturated, so the cement does not readily precipitate out, and the formation of limestones typically requires burial into the subsurface. In cool-water carbonates, shells constructed of the unstable carbonate mineral, aragonite, may even dissolve, leaving no record of these "fossils" at all. The cool sea water record often only contains shells made of the more stable form of calcium carbonate, calcite. Because the way in which cool-water limestone forms is so different, and has been so late in being recognised, research on cool-water limestones lags tropical work by at least two decades. Some modern textbooks still perpetuate the myth that limestones form only in shallow warm waters.
For their Marsden project, Professor Nelson's team, including French PhD student Vincent Caron, have focussed on the 25 million-year-old limestones that make up many of the ridgelines in Hawke's Bay and Wairarapa. These deposits are made up of the shells of whole and broken oysters, scallops and barnacles that accumulated in a shallow, cool-water seaway that extended the length of eastern North Island at the time. The team has made detailed descriptions of the different limestone types evident in cliff sections, including microscopic examination of the way in which the tiny shell fragments are cemented together. These reveal that the limestones are typically built up by repetitive units, each from a few metres to about 15 metres thick, which vary systematically in their properties from bottom to top.
The figure shows the limestone forming Te Mata Peak behind Havelock North, where 12 such cycles or sequences (S1 to S12) have been found, each bounded by erosion surfaces or discontinuities (D) that mark a distinctive break in limestone accumulation. These breaks are related to seafloor erosion when the depth of sea water was at its shallowest point. As sea levels cycled up and down, brought about by fluctuating changes in global climate, limestone accumulated above the discontinuity, before shallow waters again formed an erosion surface.
Based on the changes in texture and fossil types in the limestone cycles, the researchers found that the water varied in depth from 10-80 metres. Independent evidence suggests that the limestone cycles may reflect changes in global ice volume, and hence sea level, having a periodicity of about 40,000 years, so that the 12 cycles in the Te Mata section illustrated represent about 0.5 million years of cool-water limestone deposition. However, there is considerable variation in the number and thickness of limestone cycles within the different limestone sheets. This highlights the fact that superimposed upon the sea-level changes are strong upward and downward movements in different parts of the seafloor, associated with the Pacific Ocean plate forcing its way beneath the North Island.
Recognition of the fundamental importance of sea-level change in controlling not only the large-scale features of the cool-water limestones, but also the way the grains of carbonate are bound together, is the major impact of this study. As a result the team has developed models for the evolution of cool-water limestones under different conditions of rising, stable and falling sea levels that should have wide application in carbonate sedimentology. The reputation of the team and the natural laboratory provided by New Zealand brings researchers from all over the world to study these sediments.
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For more information,
contact Professor Campbell Nelson Department of Earth Sciences University of Waikato Private Bag 3105 Hamilton Tel. (07) 838 4024, ext 4698 Email: c.nelson@waikato.ac.nz |
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Professor Dame Anne Salmond. |
When Captain Cook made his three epic voyages around the Pacific in the late 18th century, two vastly different cultures met and interacted closely with each other for the first time. Both were profoundly affected by the encounters, in both positive and at times extremely negative ways.
The Trial of the Cannibal Dog, funded by a Marsden grant, examines in detail the cross-cultural dynamics of Cook's three Pacific voyages, analysing how each culture was affected by contact with the other, both on board Cook's ships and during his visits to the islands. Author, Professor Dame Anne Salmond, Pro Vice-Chancellor and Professor of Anthropology at The University of Auckland, has spent a lifetime studying the relationships between Europeans and Polynesians, and this book, published by Penguin, is the result of that work.
Many biographies of Cook have already been written which discuss details of his life and journeys. This book however, is a little different, as not only does it chronicle Cook's three journeys in rich and intricate detail, but it also examines in detail the effects of the encounters on both the Europeans and the Polynesians. On the one hand the book looks at the impact of Cook's visit on the island communities. For example, says Professor Salmond in her book, "They learned to speak English, to eat European food and wear European clothes, and had exotic experiences". On the other hand, the book examines how Cook and his crew were influenced by their experiences ashore on their voyages, and their relationships on board ship with Polynesian shipmates. For example, the sailors acquired tattoos, learned to eat Pacific food, and to speak Polynesian languages.
As well as the positive sides of the interactions between the two cultures, the book also looks at the problems and tensions that inevitably occurred. Eventually, these tensions led to a deterioration of relations on board ship and on shore, leading ultimately to Cook's death in Hawaii on his third voyage.
As Professor Salmond's book confirms, Captain Cook's voyages are now most famous for the contact he and his crew made with the Pacific islands. But the reason his trip was proposed in the first place was actually as a scientific mission.
The official reason for Cook's first voyage to the South Pacific in 1769 was to observe the Transit of Venus from Tahiti. The Transit of Venus is an astronomical event which involves the planet Venus passing directly between the Earth and the Sun.
Astronomer Edmond Halley had suggested in 1716 that simultaneous measurements of the Transit of Venus at widely spaced geographical locations could be used to accurately calculate the distance of the Earth from the Sun. By observing Venus passing across the Sun, the speed of the planet's orbit could be calculated, and through trigonometry, the distance of the Earth from the Sun could be determined. As a result, a trip to the South Pacific to observe the Transit of Venus was commissioned by the Royal Society of London, with support from King George III, and Cook was appointed as captain.
What was not known at the time, however, was that Cook's mission had an ulterior motive. In complete secrecy, the British Admiralty instructed Cook to search for a landmass in the South Pacific - the "Great Southern Continent" that was thought to exist. His trip revealed that no such continent existed, and this discovery, together with his encounters with the Pacific islands are what he is now most famous for.
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The Transit of Venus is a relatively rare event, occurring in pairs eight years apart, once every approximately 120 years. The next Transit of Venus will occur on 8 June 2004. To mark the occasion, the Royal Society of New Zealand, with sponsorship from the Freemasons of New Zealand, will send a party of nine students and three teachers to Britain to observe the Transit of Venus, and to visit sites of historical and scientific importance. To win places on the 2004 Transit of Venus Expedition to Britain, teams comprising three students and one teacher from each school must produce a video and supporting material exploring an aspect of Cook's first voyage, Polynesian or Maori culture at the time, or astronomy, including the Transit of Venus. The competition is open to all Year 9-13 students, and will be judged by Professor Dame Anne Salmond. Together with the competition, the Royal Society of New Zealand will also be coordinating a series of events spanning the historical, astronomical and broader scientific and cultural aspects of the Transit of Venus and its place in New Zealand history. |
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For more information, contact
Professor Dame Anne Salmond Office of the Vice-Chancellor The University of Auckland Private Bag 92019 Auckland Tel: (09) 373 7599, ext. 84774 Email: a.salmond@auckland.ac.nz |
John Mulgan was one of New Zealand's most influential writers, scholars and soldiers. His 1939 novel Man Alone is considered one of New Zealand's classics, and Mulgan himself is regarded as a central figure in both our literature and our sense of national identity. Now, Mulgan's life and work has been recognised with the publication of a detailed new biography.
Funded by a Marsden grant and published by Penguin, Long Journey to the Border is an in-depth biography of Mulgan. Author, Professor Vincent O'Sullivan, recently retired as Professor of English at Victoria University, has had a long-standing interest in Mulgan, and this book is the result.
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Professor Vincent O'Sullivan. |
Born in 1912, John Mulgan was the elder son of one of New Zealand's most influential newspaper editors and journalists, Alan Mulgan. John was an excellent student, gaining an undergraduate degree at Auckland University. He then attended Oxford University, funding himself through journalism work, and graduated early with an English degree with first class honours.
After graduating, Mulgan joined Oxford University Press for a short time as a publisher, and then worked as a journalist and novelist. During this period, he wrote his best known work, Man Alone, often thought of as a celebration of aloneness. In fact, Professor O'Sullivan says, it was actually a commentary on New Zealand politics and society at the time, told through the life story of one man, living at the time of the Depression. A testament to its impact, Man Alone has now been in print for over 50 years, one of the few New Zealand texts to have achieved this type of longevity.
Just before the outbreak of World War II, Mulgan joined up as a soldier in a British regiment. After serving at El Alemain, where he risked court-martial for charging his commanding officer with incompetence, he transferred to the Special Operations Executive in Greece. As well as winning the Military Cross, he was the only non-Greek officer to command a Greek communist guerilla unit with the 11th Thessaly Division of ELAS forces.
His celebrated work on New Zealanders and New Zealandness, Report on Experience, was written just before his death. Tragically, his life ended all too early when he committed suicide in Cairo on Anzac Day 1945, leaving behind his wife and young son. He was just 33 years old.
Despite Mulgan's influence on New Zealand literature, very little had been written about his life. Long Journey to the Border aimed to rectify this omission. The project involved drawing on a large range of materials, including archival, manuscript and printed resources. During the course of the research, Professor O'Sullivan reviewed almost 400 letters and other papers held in New Zealand. He also travelled widely, to Oxford, Northern Ireland, London, and Greece to research records and documents related to Mulgan's life.
The result is a book that, for the first time, details every aspect of Mulgan's life, from his childhood and youth in Christchurch and Auckland, to his time overseas. Long Journey to the Border traces Mulgan's life in chronological order, divided into eight consecutive phases. The book presents Mulgan at a personal level, and also explores his role in the wider context of New Zealand society at the time.
On a personal level, the book examines issues about Mulgan's life such as why he committed suicide - an event that was a mystery even to those closest to him. In examining Mulgan in a wider context, Professor O'Sullivan argues the importance and complexity of the role Mulgan had, through his writing, in formulating national identity.
Professor O'Sullivan has himself had a distinguished career as both a writer
and a critic and researcher of others' work. He was made a Distinguished Companion
of the New Zealand Order of Merit for his services to literature, and has won
the Montana New Zealand book award for both fiction and poetry. Throughout his
career he has written a wide variety of novels, short stories, poetry and plays.
Long Journey to the Border is his first excursion into a new genre, biography.
Long Journey to the Border was launched at Parliament on 5 November 2003 by Dr Claudia Orange, at an event hosted by the Speaker of the House of Representatives, the Rt Hon. Jonathan Hunt.
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For more information,
contact Professor Vincent O'Sullivan School of English, Film and Theatre Victoria University of Wellington P.O Box 600 Wellington Tel: (04) 463 6813 Email: vincent.osullivan@vuw.ac.nz |
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The English edition of this popular science book, published by Cambridge University Press and written by Dr William Tobin, is now available. The French edition was published a year ago (see Marsden Update No. 22).
This is one of the prestigious Graduate Texts in Mathematics series, published by Springer-Verlag, which bridges the gap between mathematical research and graduate teaching. The authors Colin Maclachlan and Alan Reid, who are based overseas, have been involved in a number of Marsden projects. Indeed, a good proportion of the recent research included in the book has arisen from Marsden contracts led by Professors Gaven Martin, Marston Conder and Vaughan Jones.
A textbook on the mathematical theory behind phylogenetic methods - the drawing and analysis of evolutionary trees and networks to represent relationships between species. Containing detailed mathematical explanations, examples and exercises, this book, by Dr Charles Semple and Professor Mike Steel, is aimed at graduate students in the area of evolutionary biology. The book was published by Oxford University Press earlier this year, as part of the Oxford Lecture Series in Mathematics and its Applications.
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A chronological collection of the poems of New Zealand journalist, poet and novelist Robin Hyde. This is the first time her entire 500 plus set of poems has been published together. Edited by Dr Michele Leggott, the book was published this year by Auckland University Press.
This is a discussion of the practical value of historical research applied to musical performance, published by Boydell & Brewer. Author Professor Peter Walls defends the practical value of trying to determine how music sounded in the past. He writes:
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"The invitation to give the Waynflete Lectures at Magdalen College in Oxford provided the stimulus to talk about the rationale for research into historical performance practice and its application to actual performance. This area has always been controversial but debate on the rationale for what is often called 'historically-informed performance' had intensified during the 1990s. I had become increasingly frustrated with some of the rather simplistic assumptions that were made about the motivation for and usefulness of research in historical performance practice. The Waynflete lectures gave me the opportunity to replace these assumptions with what I hoped would be a more sophisticated view of the issues at stake.
"Dealing with this subject involved me in taking some of the new theorists head on. Inevitably, in the process of attempting to hammer out a fresh rationale for performance practice research, I became increasingly aware and appreciative of the new insights that postmodern theory could offer.
"The original lectures presented my argument through a series of case studies that ranged from some drawn from my 'core' research on 17th and 18th century string playing to others that drew on much later material. To the lectures themselves, I added a further three chapters dealing with aspects of the topic that could not have been accommodated within the original time frame. "My hope is that academics, performers, and graduate students will all find this book stimulating. Writing it gave me a great deal of enjoyment and it has had the effect of bringing about a significant and, I think, very positive shift in the orientation of my own performance practice research."
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The protein, Bcl-w, with the tail shown in black. |
Despite its somewhat negative connotations, cell death is actually essential for health. During each and every second about a million new cells are created inside the human body, and in turn, a million old or damaged cells must die to make room. This balance of cell creation and destruction is vital. If too few cells die on cue, an accumulation of them occurs which can lead to diseases such as cancer or autoimmune disease.
Dr Catherine Day from the Biochemistry Department at Otago University, together with Drs Mark Hinds and David Huang from the Walter and Eliza Hall Institute in Melbourne, has been studying how certain proteins interact to regulate the process of programmed cell death (apoptosis). Specifically the research team's work centres around a protein named Bcl-w, which is a member of a family of proteins, all of which function to keep cells alive. When it is time for a cell to die, Bcl-w is inactivated by a signal from another family of "cell-killer" proteins. The life-preserving Bcl-w is neutralised only when these cell-killer proteins bind to it, and this initiates the process of cell death.
Dr Day and her colleagues have undertaken work, supported by a Marsden grant, which has led to the determination of the three-dimensional structure of Bcl-w. The new three-dimensional image shows all the lumps, bumps and grooves on the molecule's surface.
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Dr Catherine Day
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Previous work suggested that cell-killer proteins target a freely accessible groove present on the surface of Bcl-w. However, the new three-dimensional image reveals that the groove on Bcl-w targeted by cell-killer proteins is not freely accessible, but is hidden by a protective "tail" of Bcl-w that folds back into the groove.
It appears that the tail of Bcl-w prevents most molecules from binding to the protein, since this may cause accidental cell death. It is only when the cell-killer proteins are specifically unleashed to bind Bcl-w that the tail can be forcibly removed and cell death follows.
Importantly, the groove targeted for binding by cell-killer proteins is also a good target for drugs that mimic their action, and therefore there has been a great deal of interest among research groups and the pharmaceutical industry in discovering such drugs for cancer treatment. To date, novel anti-cancer drugs that target molecules like Bcl-w may have failed because of the belief that the groove was empty and freely accessible.
As a result of the work of Dr Day and her colleagues, it is now known that only cell-killer proteins can remove the tail on Bcl-w and therefore bind to it, leading to cell death. Ongoing work by this research team is also aimed at determining other features that are important for the interaction of these two opposing families of molecules. It is hoped this fundamental research may ultimately lead to the development of new therapeutic compounds.
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For more information, contact
Dr Catherine Day Biochemistry Department University of Otago P O Box 56 Dunedin Tel: (03) 479 7871 Email: catherine.day@stonebow.otago.ac.nz |
The first four years of a child's life involve a remarkable degree of physical, social, emotional, and intellectual change. At no other time is the rate of development so rapid or so dramatic. A great deal of what is learned during these early years forms a basis for the rest of life, yet as most people are aware, adults generally have little or no recollection of their early experiences. This inability to recall experiences from our infancy and early childhood is a phenomenon known as childhood amnesia.
Professor Harlene Hayne and her colleagues at the University of Otago's Department of Psychology have undertaken research, supported by a Marsden grant, to try to understand the mechanism responsible for childhood amnesia.
Psychologists have always argued that early experience is extremely important in development, and that events that occur when we are young have a greater and more lasting impact than if the same events or experiences are encountered when we are older. The importance of early experience was the cornerstone of Freudian theory and was also reflected in a number of subsequent theories of social and emotional development.
Recent advances in neuroscience provide additional support for this view by showing that early experiences also play a fundamental role in brain development. At birth, the human infant brain weighs approximately 350 grams, and this more than quadruples by the time a person reaches adulthood. The enormous change in weight is due primarily to an increase in the connections between the neurons that make up the human brain. These connections are established very rapidly during infancy and are influenced heavily by early experience.
Despite the fact that early experience has such an important effect on both behavioural and neural development, most adults have little or no recollection of their early, formative experiences.
Freud coined the term infantile or childhood amnesia to describe the inability of adults to remember events from their infancy and early childhood.
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| These photographs show a child during both phases of the test procedure. The child is initially shown two identical pictures (left photo). Following a delay of days, weeks or months, he is shown the original picture paired with a new one (right photo). If the child remembers the original picture, then he should look longer at the new picture during the test. | |
The phenomenon of childhood amnesia raises critical questions about the continuity of memory processing across the life span. Are there fundamental changes in memory during development? If so, what are they and when do they occur? In the past, there have been numerous attempts to identify the mechanisms responsible for childhood amnesia. Freud, for example, originally argued that memories of our infancy and early childhood were "repressed" due to their unacceptable sexual and aggressive content. This idea, however, has now largely been discounted.
Current explanations for childhood amnesia include changes in basic memory mechanisms that are likely to occur in both humans and other animals, to changes in higher order cognitive functions that probably occur only in humans. The goal of Professor Hayne's research has been to understand which, if any, of these explanations is correct. To do this, she has studied memory development during infancy and early childhood, which encapsulates the period of childhood amnesia.
Because infants and young children are typically unable to tell researchers what they remember, Professor Hayne and her students have used a number of nonverbal techniques to study memory development. In one of these techniques, infants and children are briefly shown a novel picture. Following a delay of seconds, days, or months, participants are shown two pictures; one of these pictures appeared before and the other one is new. Because infants and children are inherently interested in novelty, if they remember the original picture, they are most likely to look at the new one during the test.
Using this technique (and others), Professor Hayne has shown that there are at least three fundamental changes in memory ability during the period of childhood amnesia. First, older participants encode information more quickly than younger participants, increasing the strength and content of the initial memory representation. Second, older participants remember longer than younger participants. In the looking task described here, retention improves by a factor of 180 over the first 4 years of life. Third, older participants can retrieve and use their memories in a wider range of circumstances. Memory retrieval by infants is highly specific to the conditions of original encoding if any aspect of the original task is changed, retention suffers. This high degree of specificity suggests that it may be difficult if not impossible for early memories to be retrieved by cues (or in contexts) that were not a part of the original experience. As such, our early memories probably go unretrieved and unexpressed and are eventually lost through disuse. As memory retrieval becomes increasingly more flexible during early childhood, individual memories are more likely to be retrieved, and their repeated retrieval will ultimately prolong subsequent retention.
Taken together, Professor Hayne has shown that there are fundamental changes in basic memory skill during the period of childhood amnesia. These age-related changes in basic encoding, retention, and retrieval provide a simple explanation of childhood amnesia that is not unique to humans, but may describe more fundamental processes common to memory development in all mammalian species.
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For more information, contact
Professoor Harlene Hayne Psychology Department University of Otago P O Box 56, Dunedin Tel: (03) 479 7636 Email: hayne@psy.otago.ac.nz |
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Professor Diana Hill |
Global Technologies (NZ) Ltd
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Dr Garth Carnaby
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Wool Research Organisation of New Zealand (Inc)
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Professor Rob Ballagh
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University of Otago
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Professor Pat Bergquist
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The University of Auckland and Macquarie University
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Professor Sally Casswell
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Massey University
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Professor Marston Conder
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The University of Auckland
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Professor Charles Daugherty
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Victoria University of Wellington
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Mr Jonathan Mane-Wheoki
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University of Canterbury
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Professor Pat Sullivan
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Massey University
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Dr David Wratt
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National Institute of Water and Atmospheric Research Ltd
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Dr Don Smith, Manager. Tel: 04-470 5776; Email: don.smith@rsnz.org
Dr Peter Gilberd, Deputy Manager. Tel: 04-470 5778; Email: peter.gilberd@rsnz.org
Dr Rachel Averill, Research Assessor. Tel:04-470 5774: Email: rachel.averill@rsnz.org
Dr Tasha Black, Research Assessor. Tel: 04-470 5774; Email: tasha.black@rsnz.org
Rochelle Barton, Administration Officer. Tel: 04-470 5799; Email: rochelle.barton@rsnz.org
Janet Sorensen, Administration Officer. Tel: 04-470 5788; Email: janet.sorensen@rsnz.org
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Marsden Update is published quarterly by the Marsden Fund and is available free on request. Editor: Anna Meyer. Email: ameyer@paradise.net.nz