136 resultados para Steven Johnson

em University of Queensland eSpace - Australia


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Plant cyanogenesis, the release of cyanide from endogenous cyanide-containing compounds, is an effective herbivore deterrent. This paper characterises cyanogenesis in the Australian tree Eucalyptus polyanthemos Schauer subsp. vestita L. Johnson and K. Hill for the first time. The cyanogenic glucoside prunasin ((R)-mandelonitrile beta-D-glucoside) was determined to be the only cyanogenic compound in E. polyanthemos foliage. Two natural populations of E. polyanthernos showed quantitative variation in foliar prumasin concentration, varying from zero (i.e. acyanogenic) to 2.07 mg CN g(-1) dry weight in one population and from 0.17 to 1.98 mg CN g(-1) dry weight in the other. No significant difference was detected between the populations with respect to the mean prunasin concentration or the degree of variation in foliar prunasin, despite significant differences in foliar nitrogen. Variation between individuals was also observed with respect to the capacity of foliage to catabolise prunasin to form cyanide. Moreover, variation in this capacity generally correlated with the amount of prunasin in the tissue, suggesting genetic linkage between prunasin and beta-glucosidase. (C) 2002 Elsevier Science Ltd. All rights reserved.

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US President Lyndon Johnson's state visit to Australia in October 1966, came at the pinnacle of support for Australia's military involvement in the Vietnam War. Johnson's visit also occurred just weeks before an election for the House of Representatives at which the ruling Liberal-Country Party Coalition won its eighth successive, and largest victory, The proximity of these events has led many to argue that a causal relationship exists between the two. Advocates of this thesis, however, have failed to support their position with any evidence other than the anecdotal. Contrary to the assertions made by numerous political historians and observers of the period, this paper finds no evidence to support a thesis of causality. This paper argues that the Coalition's landslide victory in 1966 was both a rejection of the tired and lacklustre leadership of Labor's Arthur Calwell and a measure of the electorate's overwhelming support for Holt and his Government's policies of conscription and military involvement in Vietnam.

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We describe the creation process of the Minimum Information Specification for In Situ Hybridization and Immunohistochemistry Experiments (MISFISHIE). Modeled after the existing minimum information specification for microarray data, we created a new specification for gene expression localization experiments, initially to facilitate data sharing within a consortium. After successful use within the consortium, the specification was circulated to members of the wider biomedical research community for comment and refinement. After a period of acquiring many new suggested requirements, it was necessary to enter a final phase of excluding those requirements that were deemed inappropriate as a minimum requirement for all experiments. The full specification will soon be published as a version 1.0 proposal to the community, upon which a more full discussion must take place so that the final specification may be achieved with the involvement of the whole community. This paper is part of the special issue of OMICS on data standards.

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A narrow absorption feature in an atomic or molecular gas (such as iodine or methane) is used as the frequency reference in many stabilized lasers. As part of the stabilization scheme an optical frequency dither is applied to the laser. In optical heterodyne experiments, this dither is transferred to the RF beat signal, reducing the spectral power density and hence the signal to noise ratio over that in the absence of dither. We removed the dither by mixing the raw beat signal with a dithered local oscillator signal. When the dither waveform is matched to that of the reference laser the output signal from the mixer is rendered dither free. Application of this method to a Winters iodine-stabilized helium-neon laser reduced the bandwidth of the beat signal from 6 MHz to 390 kHz, thereby lowering the detection threshold from 5 pW of laser power to 3 pW. In addition, a simple signal detection model is developed which predicts similar threshold reductions.

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Brian Laver speaking at the demonstration to protest the visit of President Lyndon Johnson to Brisbane during the Vietnam War in January 1966. Jack Sherrington can be seen on extreme right of photograph.

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Parson speaking at LBJ visit to Brisbane, Australia in 1966. Alf Saunders, Communist Party of Australia member and PMG linesman is facing the parson. Demonstrations were held during the visit to Australia by President Lyndon Johnson.

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