Muddy ovals under threat from climate change

Questions are raised about the wisdom of continuing the policy of unending global economic growth in the face of climate change. Alternate forms of economic organisation need to be devised, without which global warming may even lead to the elimination of cold, muddy football fields.

Total synthesis of (±)-hyphodermins A and D

An efficient formal synthesis of (±)-hyphodermins A and D, metabolites of Hyphoderma radula, has been completed in 12 and 11 steps, respectively. The tricyclic carbon skeleton of enone 6 was rapidly assembled from diester 11 via an α brominationn−elimination sequence followed by anhydride formation. Regioselective reduction of the lactone group of enone 6 with LiAlH(t-BuO)3 gave lactol 15. Lactol 15 was converted in two steps to (±)-hyphodermin D, without the need for complex protection−deprotection strategies. Lactol 15 was converted in three steps to (±)-hyphodermin A, via the key step of epoxidation of an enone in the presence of a THP lactol. A combination of NMR and ab initio studies suggests that the structures of hyphodermin C and D should be interchanged.

A question of self-preservation : immunopathology in influenza virus infection

Influenza A viruses that circulate normally in the human population cause a debilitating, though generally transient, illness that is sometimes fatal, particularly in the elderly. Severe complications arising from pandemic influenza or the highly pathogenic avian H5N1 viruses are often associated with rapid, massive inflammatory cell infiltration, acute respiratory distress, reactive hemophagocytosis and multiple organ involvement. Histological and pathological indicators strongly suggest a key role for an excessive host response in mediating at least some of this pathology. Here, we review the current literature on how various effector arms of the immune system can act deleteriously to initiate or exacerbate pathological damage in this viral pneumonia. Generally, the same immunological factors mediating tissue damage during the anti-influenza immune response are also critical for efficient elimination of virus, thereby posing a significant challenge in the design of harmless yet effective therapeutic strategies for tackling influenza virus.

Protection and compensation in the influenza virus-specific CD8+ T cell response.

Influenza virus-specific CD8+ T cells generally recognize peptides derived from conserved, internal proteins that are not subject to antibody-mediated selection pressure. Prior exposure to any one influenza A virus (H1N1) can prime for a secondary CD8+ T cell response to a serologically different influenza A virus (H3N2). The protection afforded by this recall of established CD8+ T cell memory, although limited, is not negligible. Key characteristics of primary and secondary influenza-specific host responses are probed here with recombinant viruses expressing modified nucleoprotein (NP) and acid polymerase (PA) genes. Point mutations were introduced into the epitopes derived from the NP and PA such that they no longer bound the presenting H2Db MHC class I glycoprotein, and reassortant H1N1 and H3N2 viruses were made by reverse genetics. Conventional (C57BL/6J, H2b, and Ig+/+) and Ig-/- (muMT) mice were more susceptible to challenge with the single NP [HKx31 influenza A virus (HK)-NP] and PA (HK-PA) mutants, but unlike the Ig-/- mice, Ig+/+ mice were surprisingly resistant to the HK-NP/-PA double mutant. This virus was found to promote an enhanced IgG response resulting, perhaps, from the delayed elimination of antigen-presenting cells. Antigen persistence also could explain the increase in size of the minor KbPB1703 CD8+ T cell population in mice infected with the mutant viruses. The extent of such compensation was always partial, giving the impression that any virus-specific CD8+ T cell response operates within constrained limits. It seems that the relationship between protective humoral and cellular immunity is neither simple nor readily predicted.

Reducing the bandwidth requirements of P2P keyword indexing

This paper describes the design and evaluation of a peer-to-peer indexing system to integrate the resources of local document database systems into a globally addressable index using a distributed hash table. The salient feature of the indexing systems design is the efficient dissemination of term-document indices using a combination of duplicate elimination, ring based forwarding and conventional techniques such as aggressive index pruning, and batching. Together these indexing strategies help to reduce, the number of RPC operations required to locate the nodes responsible for a section of the index, the bandwidth utilization and the latency of the indexing service.

An EM-based algorithm for clustering data streams in sliding windows

Cluster analysis has played a key role in data understanding. When such an important data mining task is extended to the context of data streams, it becomes more challenging since the data arrive at a mining system in one-pass manner. The problem is even more difficult when the clustering task is considered in a sliding window model which requiring the elimination of outdated data must be dealt with properly. We propose SWEM algorithm that exploits the Expectation Maximization technique to address these challenges. SWEM is not only able to process the stream in an incremental manner, but also capable to adapt to changes happened in the underlying stream distribution.

Incremental and adaptive clustering stream data over sliding window

Cluster analysis has played a key role in data stream understanding. The problem is difficult when the clustering task is considered in a sliding window model in which the requirement of outdated data elimination must be dealt with properly. We propose SWEM algorithm that is designed based on the Expectation Maximization technique to address these challenges. Equipped in SWEM is the capability to compute clusters incrementally using a small number of statistics summarized over the stream and the capability to adapt to the stream distribution’s changes. The feasibility of SWEM has been verified via a number of experiments and we show that it is superior than Clustream algorithm, for both synthetic and real datasets.

An approach to filtering RFID data streams

RFID is gaining significant thrust as the preferred choice of automatic identification and data collection system. However, there are various data processing and management problems such as missed readings and duplicate readings which hinder wide scale adoption of RFID systems. To this end we propose an approach that filters the captured data including both noise removal and duplicate elimination. Experimental results demonstrate that the proposed approach improves missed data restoration process when compared with the existing method.

Mechanisms governing the enhanced thermal stability of acid and base treated polypyrrole

One of the major problems associated with the use of polypyrrole (PPy) in a practical engineering application is its poor thermal stability at elevated temperatures, especially in the presence of oxygen and moisture. Several authors have shown that enhanced stability can be achieved through treatment with simple acids and bases. This paper presents a summary of the possible structural changes which occur as a result of these treatments and those that appear to be related to enhanced conductivity stability. A slight increase in conductivity (10–20%) is observed for acid treated PPy films which is found to be the result of protonation of the pyrrole structure. This effect is dramatically enhanced by treatment at high temperatures where an increase in conductivity of >84% can be achieved. Base treatment of the PPy films results in the deprotonation of the pyrrole structure leading to the loss of conductivity (>40%). Preliminary X-ray Photoelectron Spectroscopy (XPS) results indicate that both acid and base treatment resulted in the elimination of reactive sites for oxygen. Long term thermal ageing of these treated films were conducted at 150 °C in air. The conductivity decay behaviour was found to follow multiple first order chemical reaction kinetics.

Genetic status of an endemic marine mammal, the Australian fur seal, following historical harvesting

Genetic variation, and the way in which it is partitioned among populations, has implications for a species’ survival and evolutionary potential. Such information is particularly important for the successful conservation and management of species that have experienced past human impacts and potential losses of genetic diversity. Overharvesting of the Australian fur seal Arctocephalus pusillus doriferus in the 18th and 19th centuries resulted in severe population reductions and elimination of an estimated 17 of 26 colonies. Currently, the subspecies is recovering and c. 20 000 pups are produced annually at 13 colony sites, most of which are situated in Bass Strait in south-eastern Australia. Genetic analysis of samples collected from pups captured at nine colonies revealed no difference in allelic diversity or heterozygosity at five microsatellite loci and no differences in haplotype diversity within a 344 bp region of the mitochondrial DNA control region. There was some evidence for isolation by distance but the program STRUCTURE predicted a single cluster of individuals. Gene flow among colonies appears to be substantial at present, indicating that the Australian fur seal is currently a single, panmictic unit.

Improving the effectiveness of the Sex Discrimination Act: recommendations from the 2008 Senate Inquiry

One way to characterise the Rudd Government’s first year in office would be by the flurry of inquiries and reports that it commissioned. Three related to gender equality. The Productivity Commission conducted an inquiry into a national paid maternity, paternity and parental leave scheme and the House of Representatives Standing Committee on Employment and Workplace Relations conducted an inquiry into pay equity. This article is concerned with a third inquiry — the Senate Standing Committee on Legal and Constitutional Affairs (the committee) inquiry into the effectiveness of the Sex Discrimination Act 1984 (Cth) (SDA) in eliminating discrimination and promoting gender equality. These inquiries were not the Rudd Government’s only activities in relation to sex discrimination and gender equality. It also enacted legislation which removed discrimination against same sex couples from 68 Commonwealth laws and announced its intention to accede to the Optional Protocol to the International Convention on the Elimination of All Forms of Discrimination against Women.

Centring the subject in order to educate

It is important for educators to recognise that the various calls to decentre the subject—or self—should not be interpreted as necessarily requiring the removal of the subject altogether. Through the individualism of the Enlightenment the self was centred. This highly individualistic notion of the sovereign self has now been decentred especially through post-structuralist literature. It is contended here however, that this tendency to decentre the subject has been taken to an extreme at times, especially by some designers of school frameworks and curricula, who have eliminated the subject altogether. Such elimination is argued to contribute to the numbers of youth who are dropping out of school. By adopting an existential perspective and by drawing mainly upon Kierkegaard's subjective truth and Dewey's notion of centeredness, the case is made that for education the subject should not only be included but should actually be centred—at least momentarily.

Sucrose as an added sweetener in diabetes mellitus

For many years the Diabetes Associations of several countries have recommended the dietary elimination of added sucrose. However, contrary to popular belief, there is no evidence that modest use of added sucrose is detrimental to diabetic control. In this study of 17 non-insulin dependent diabetics, the medium-term metabolic effects of the daily supplementation of a subject's usual diet with either 28 g of sucrose or with saccharin and starch of equivalent sweetener and energy value, were compared over six-week periods. Neither dietary period had any significant effect on fasting concentrations of blood glucose, plasma insulin, GIP or serum triglyceride. The metabolic responses to two different test meals, consisting of a standard breakfast supplemented with either sucrose or saccharin plus starch, did not differ significantly either between test meals or between dietary periods. Similarly neither dietary period had any significant effect on urinary excretion of glucose. Na+ or K+. There was no significant difference in mean blood pressure between dietary periods.

The results of this medium-term study indicate that there are no metabolic contraindications to including a moderate amount of sucrose (up to 28 g e 7 teaspoons) in the diets of patients with non-insulin dependent diabetes mellitus.

Animal–plant–microbe interactions : direct and indirect effects of swan foraging behaviour modulate methane cycling in temperate shallow wetlands

Wetlands are among the most important ecosystems on Earth both in terms of productivity and biodiversity, but also as a source of the greenhouse gas CH₄. Microbial processes catalyzing nutrient recycling and CH₄ production are controlled by sediment physico-chemistry, which is in turn affected by plant activity and the foraging behaviour of herbivores. We performed field and laboratory experiments to evaluate the direct effect of herbivores on soil microbial activity and their indirect effects as the consequence of reduced macrophyte density, using migratory Bewick’s swans (Cygnus columbianus bewickii Yarrell) feeding on fennel pondweed (Potamogeton pectinatus L.) tubers as a model system. A controlled foraging experiment using field enclosures indicated that swan bioturbation decreases CH₄ production, through a decrease in the activity of methanogenic Archaea and an increased rate of CH₄ oxidation in the bioturbated sediment. We also found a positive correlation between tuber density (a surrogate of plant density during the previous growth season) and CH₄ production activity. A laboratory experiment showed that sediment sterilization enhances pondweed growth, probably due to elimination of the negative effects of microbial activity on plant growth. In summary, the bioturbation caused by swan grazing modulates CH₄ cycling by means of both direct and indirect (i.e. plant-mediated) effects with potential consequences for CH₄ emission from wetland systems.

On the classification of image features

While the primary purpose of edge detection schemes is to be able to produce an edge map of a given image, the ability to distinguish between different feature types is also of importance. In this paper we examine feature classification based on local energy detection and show that local energy measures are intrinsically capable of making this classification because of the use of odd and even filters. The advantage of feature classification is that it allows for the elimination of certain feature types from the edge map, thus simplifying the task of object recognition.