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The Tasmanian Cenozoic macrofossil record is relatively rich, and changes that have occurred in the vegetation of the region are becoming increasingly well understood. The record is essentially one of rainforest elements, especially in the Paleogene, but taxa that are now common in sclerophyllous heathlands and woodlands are increasingly prevalent in Quaternary sediments.
Extant Tasmanian rainforest is renowned for its beauty, and botanists have long recognised its marked taxonomic and structural similarity to other southern hemisphere ‘cool temperate’ forests of New Zealand and Chile. These are generally dominated by Nothofagus trees, their boughs laden with lichens and verdant shrouds of bryophytes. Other links are often made by phytogeographers to similar forests in high altitude regions of northern New South Wales and the much more species-rich vegetation of the generally montane regions of New Guinea and New Caledonia where Nothofagus also grows. A striking aspect of these forests is the presence of a variety of conifers, principally Podocarpaceae, but also Cupressaceae and Araucariaceae. In Tasmania the Araucariaceae are extinct, but the region is unique in the southern hemisphere in having a genus of Taxodiaceae, Athrotaxis. Athrotaxis spp. are often associated with Australia's only winter deciduous plant, Nothofagus gunnii, in montane regions of the island. The macrofossil record shows conclusively that the current diversity of Tasmania's woody rainforest flora is very much lower than at any other time during the Cenozoic. It confirms that there are strong floristic links to regions as widespread as eastern and southwestern mainland Australia, southern South America, New Zealand and New Guinea. In fact, Tasmanian Paleogene floras contain a wealth of taxa that are closely related to plants now confined to these regions.
Apart from the relatively large tracts of rainforest in Tasmania, closed forest lacking eucalypts is now confined to small patches along the east coast of Australia. In contrast to mainland Australia, Tasmania is relatively mountainous and has a well-developed woody alpine vegetation, dominated by shrubs of the Asteraceae, Epacridaceae, Myrtaceae and Proteaceae.
The Australian vegetation is the end result of a remarkable history of climate change, latitudinal change, continental isolation, soil evolution, interaction with an evolving fauna, fire and most recently human impact. This book presents a detailed synopsis of the critical events that led to the evolution of the unique Australian flora and the wide variety of vegetational types contained within it. The first part of the book details the past continental relationships of Australia, its palaeoclimate, fauna and the evolution of its landforms since the rise to dominance of the angiosperms at the beginning of the Cretaceous period. A detailed summary of the palaeobotanical record is then presented. The palynological record gives an overview of the vegetation and the distribution of important taxa within it, while the complementary macrofossil record is used to trace the evolution of critical taxa.
This book will interest graduate students and researchers interested in the evolution of the flora of this fascinating continent.
In examining the fossil record of the Australian flora since the arrival of angiosperms, several taxonomic groups loom large, either because they have an extensive and informative fossil record, or because they are prominent in the living vegetation and are selectively sought in the fossil record. The aim here is to consider some taxa that cover each of these areas in order to complement the vegetation reconstructions discussed in earlier chapters. There are several candidates that fall into the category of having an extensive fossil record, but the outstanding one is Nothofagus, which dominates many palynofloras, and is also well represented in the macrofossil record. The Podocarpaceae, Araucariaceae, Proteaceae and Casuarinaceae are also considered here because they have a mixture of good pollen and macrofossil records, and important evolutionary arguments can be based on these records. The prime example of a taxon that is prominent in the living vegetation and is actively sought in the fossil record is Eucalyptus, and its pollen and macrofossil record will also be considered, although it is much smaller than those of the other taxa. In choosing these taxa, several other notable groups have been excluded. In most cases this is because the record is biassed to either pollen (e.g. Acacia, Chenopodiaceae) or macrofossils (e.g. Lauraceae, cycads) and a combined data set cannot be supplied. There is no doubt that the greatest weakness lies with the macrofossil record, especially for those taxa that produce entire-margined, medium-sized leaves. Taxonomic research on these groups should be a priority for the future.
Nothofagus has been described as the key genus in the study of southern hemisphere plant evolution and biogeography (van Steenis, 1971,1972). There are a number of reasons for this.
1. It has a completely southern hemispheric distribution, whereas its closest relatives are, and probably always have been, northern hemispheric.
2. It occurs in all the major Gondwanic land masses except Antarctica, where it has an extensive fossil record, and Africa and India, where it has never been recorded as an autochthonous fossil.
The living Australian flora is a complex mixture of species with widely varying distributions and interactions, covering the range from arid zone grassland to rainforest, alpine heath to mangrove swamp. The latitudinal range of Australia spans tropical to cool temperate climatic zones, and this is reflected in the extant vegetation, which is enormously complex (see Groves, 1981). Attempts to explain the distribution of Australian vegetation based solely on prevailing variables have been less than satisfactory. Australia, in all its aspects, is a product of its past. That is especially true of its flora and, unless the fossil record is properly considered, all attempts to explain vegetation patterns will be incomplete. Despite the complexity of the living vegetation, there has been a tendency to consider the past vegetation, especially that of the pre-Quaternary, as consisting in widespread, monotonously uniform communities. The recent explosion in information on Australian fossil plants shows that this perception was largely the result of a highly incomplete database, where the unknown areas were assumed to be the same as the small areas that were relatively well understood. It is now clear that past vegetation complexity, at least during the Cenozoic, was as high as, or possibly higher than, that seen at present. The past complexity is abundantly illustrated in this book, which may well represent the last occasion on which a thorough review of such a large period of time can be accomplished for the whole of Australia. Data are accumulating at a rapid rate, and almost every new site produces much that is novel, causing a reassessment of the prevailing hypotheses.
There is a long history of attempts to explain the origin and evolution of the Australian flora; some of these are well known, others more obscure. Hooker's (1860) discussion of the Australian flora provided a base of the highest quality, which slowly evolved into the invasion theory, perhaps best argued by Burbidge (1960).
During the early 1990s I agreed to edit a book on the Cretaceous and Tertiary fossil plant record of Australia. A huge amount of information was available to be synthesised into a single volume, and I was fortunate to have an excellent group of people to draw on to produce a comprehensive set of chapters. Much of what they wrote has stood the test of time, and hence this reprint of that book should be a very welcome addition for anyone with an interest in the Australian fossil record. However, there have been some great advances in the last 25 years and it is important to recognise the contribution that has been made during that time to our understanding of the overall picture of the evolution of the living Australian vegetation. The best way to do this and to keep it up to date is via a website that provides details of important advances in this area over the last quarter of a century. The details of that website will be made available soon, and I invite everyone to submit relevant publications to that site.
It is an exciting time to be a palaeobotanist and the Australian fossil record promises much that is new and innovative for the future. I believe this reprint provides a very solid base that will stand for many years to come as the basis on which our reconstruction of past events can be made. The fossil record provides a vast and precious resource that demonstrates the history of life, and its relevance to our present and future well-being becomes more apparent as new approaches to using the fossil record as important tests of contemporary issues of great significance, like adaptation to climate change and determining the best approaches to fire management.
Studying the fossil record holds a strong appeal for young people and I hope this book and the associated web-based resources will attract more people to the plant fossil record of Australia, which stands as one of the great natural experiments in plant evolution.
The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4–∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.
Sildenafil is frequently prescribed to children with single ventricle heart defects. These children have unique hepatic physiology with elevated hepatic pressures, which may alter drug pharmacokinetics. We sought to determine the impact of hepatic pressure on sildenafil pharmacokinetics in children with single ventricle heart defects.
A population pharmacokinetic model was developed using data from 20 single ventricle children receiving single-dose intravenous sildenafil during cardiac catheterisation. Non-linear mixed effect modelling was used for model development, and covariate effects were evaluated based on estimated precision and clinical significance.
The analysis included a median (range) of 4 (2–5) pharmacokinetic samples per child. The final structural model was a two-compartment model for sildenafil with a one-compartment model for des-methyl-sildenafil (active metabolite), with assumed 100% sildenafil to des-methyl-sildenafil conversion. Sildenafil clearance was unaffected by hepatic pressure (clearance=0.62 L/hour/kg); however, clearance of des-methyl-sildenafil (1.94×(hepatic pressure/9)−1.33 L/hour/kg) was predicted to decrease ~7-fold as hepatic pressure increased from 4 to 18 mmHg. Predicted drug exposure was increased by ~1.5-fold in subjects with hepatic pressures ⩾10 versus <10 mmHg (median area under the curve=533 versus 792 µg*h/L).
Elevated hepatic pressure delays clearance of the sildenafil metabolite – des-methyl-sildenafil – and increases drug exposure. We speculate that this results from impaired biliary clearance. Hepatic pressure should be considered when prescribing sildenafil to children. These data demonstrate the importance of pharmacokinetic assessments in patients with unique cardiovascular physiology that may affect drug metabolism.
This study compared the performance of two new bone-anchored hearing aids with older bone-anchored hearing aids that were not fully digital.
Fourteen experienced bone-anchored hearing aid users participated in this cross-over study. Performance of their existing bone-anchored hearing aid was assessed using speech-in-noise testing and questionnaires. Participants were then fitted with either a Ponto Pro or a BP100 device. After four weeks of use with each new device, the same assessments were repeated.
Speech-in-noise testing for the 50 per cent signal-to-noise ratio (the ratio at which 50 per cent of responses were correct) showed no significant differences between the Ponto Pro and the BP100 devices (p = 0.1) However, both devices showed significant improvement compared with the participants' previous bone-anchored hearing aid devices (p < 0.001). There were no significant differences between the two new devices in the questionnaire data.
Both fully digital bone-anchored hearing aids demonstrated superior speech processing compared with the previous generation of devices. There were no substantial differences between the two digital devices in either objective or subjective tests.
This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled “Developing a new, national approach to surveillance for ventilator-associated events” and published in Critical Care Medicine. The full report provides a comprehensive description of the Working Group process and outcome.
In September 2011, the Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group to organize a formal process for leaders and experts of key stakeholder organizations to discuss the challenges of VAP surveillance definitions and to propose new approaches to VAP surveillance in adult patients (Table 1).
Efficient and reliable assessments of cognitive treatment effects are essential for the comparative evaluation of procognitive effects of pharmacologic therapies. Yet, no studies have addressed the sensitivity and efficiency with which neurocognitive batteries evaluate cognitive abilities before and after treatment. Participants were primarily first episode schizophrenia patients who completed baseline (n = 367) and 12-week (n = 219) assessments with the BACS (Brief Assessment of Cognition in Schizophrenia) and CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) neuropsychological batteries in a clinical trial comparing olanzapine, quetiapine, and risperidone. Exploratory factor analysis revealed that performance on both batteries was characterized by a single factor of generalized cognitive deficit for both baseline performance and cognitive change after treatment. Both batteries estimated similar levels of change following treatment, although the BACS battery required half the administration time. Because a unitary factor characterized baseline cognitive abilities in early psychosis as well as cognitive change after treatment with atypical antipsychotic medications, short batteries such as the BACS may efficiently provide sufficient assessment of procognitive treatment effects with antipsychotic medications. Assessment of cognitive effects of adjunctive therapies targeting specific cognitive domains or impairments may require more extensive testing of the domains targeted to maximize sensitivity for detecting specific predicted cognitive outcomes. (JINS, 2008, 14, 209–221.)Presented in part at the annual International Neuropsychology Society meeting in Portland, OR, February 2007; and the 2007 International Congress for Schizophrenia Research in Colorado Springs, CO.
We present an analysis of wide-field, far-ultraviolet images of the LMC and SMC obtained by the Ultraviolet Imaging Telescope. The photometric catalog of over 37,000 stars allows us to make large-scale, statistical studies of massive star formation in OB associations and in the field population. Our results show that: (1) the most probable slope for the initial mass function (IMF) of field stars is Γ = −1.80, slightly steeper than the Salpeter slope; and (2) there doesn't seem to be a single, unique IMF slope for stars in OB associations, with a range of values from Γ = −1.0 to −2.0. We also analyze the stellar vs. diffuse UV flux, and the population of OB star candidates in the field.