Pattern Formation in a 2D Elastic Solid

We present a dynamical theory of a two-dimensional martensitic transition in an elastic solid, connecting a high-temperature phase which is nondegenerate and has triangular symmetry, and a low-temperature phase which is triply degenerate and has oblique symmetry. A global mode-based Galerkin method is employed to integrate the deterministic equation of motion, the latter of which is derived by the variational principle from a nonlinear, nonlocal Ginzburg-Landau theory which includes the sound-wave viscosity. Our results display (i) the phenomenon of surface nucleation, and (ii) the dynamical selection of a length scale of the resultant patterns.Comment: LaTeX, 14 pages with four post-script figures included by psfig. Three of these are colour, but viewable in black-and-white. Presented at the conference "Collective Phenomena in Physics: Pattern Formation in Fluids and Materials", University of Western Ontario, London, June 199

Solid immersion lens applications for nanophotonic devices

Solid immersion lens (SIL) microscopy combines the advantages of conventional microscopy with those of near-field techniques, and is being increasingly adopted across a diverse range of technologies and applications. A comprehensive overview of the state-of-the-art in this rapidly expanding subject is therefore increasingly relevant. Important benefits are enabled by SIL-focusing, including an improved lateral and axial spatial profiling resolution when a SIL is used in laser-scanning microscopy or excitation, and an improved collection efficiency when a SIL is used in a light-collection mode, for example in fluorescence micro-spectroscopy. These advantages arise from the increase in numerical aperture (NA) that is provided by a SIL. Other SIL-enhanced improvements, for example spherical-aberration-free sub-surface imaging, are a fundamental consequence of the aplanatic imaging condition that results from the spherical geometry of the SIL. Beginning with an introduction to the theory of SIL imaging, the unique properties of SILs are exposed to provide advantages in applications involving the interrogation of photonic and electronic nanostructures. Such applications range from the sub-surface examination of the complex three-dimensional microstructures fabricated in silicon integrated circuits, to quantum photoluminescence and transmission measurements in semiconductor quantum dot nanostructures

Post-ratoon growth and yield of three hybrid papayas (Carica papaya L.) under mulched and bare-ground conditions

At Yarwun (151.3°E, 23.75°S), a trial was conducted to compare 3 papaya hybrids (Hybrid 29, Hybrid 11 and Hybrid 13) under mulching with grass hay or in bare ground. The viability of ratooning a papaya crop was also investigated. After a 16-month cropping season plants were cut to a 750-mm stump (ratooned) about monthly over a 3.5-month period and, following a 4.5-month regrowth period, were harvested for a period of 11 months (post-ratoon). Hybrid 29 yielded (by weight) 54% more than Hybrid 11 and 92% more than Hybrid 13 during the 3.5-month ratooning period. At the commencement of ratooning, Hybrid 29 plants were 41–58 cm shorter than Hybrid 11 and 13 plants, allowing the Hybrid 29 plants to be retained for longer before being ratooned. Hybrid 29 also returned to fruiting more quickly with a greater proportion of plants (97%) with fruit at the first post-ratoon harvest compared with Hybrid 11 (87%). Following regrowth (post-ratoon) the 3 hybrids produced similar yields. All 3 hybrids were equally susceptible to the 3 phytoplasma diseases and to nematodes. The plots mulched with coarse grass hay yielded 70% more during the ratooning period and 116% more post-ratoon than the plots with bare ground. This difference was attributed in part to fewer root-knot nematodes, the roots being more heavily infected with vesicular arbuscular mycorrhiza, the use of the complete upper soil profile by the roots, reduced rainfall run off and less soil loss in the mulched treatment. The highest yielding treatment, mulched Hybrid 29, averaged the equivalent of 55 t/ha.year during ratooning, 43 t/ha.year over the 11-month post-ratoon harvest period and 65 t/ha.year over the entire plant–ratoon cycle. These yields were achieved in spite of drought conditions and quite severe outbreaks of the phytoplasma diseases, dieback, yellow crinkle and mosaic, with 60% of plant positions infected with dieback during the post-ratoon period. Theoretical yield estimations using the data from the plant and post-ratoon crops indicated that ratooning may give superior average monthly yields compared with 2 successive plant crops because of the reduced time required for the ratooned crop to return to production. The study demonstrated the benefits of mulching, the superiority of Hybrid 29 and that ratooning may be successfully used in papaya. In environments similar to Yarwun, Hybrid 29, or similar hybrids, with mulching is recommended for commercial production. If land, time or finances are limiting, consideration should be given to ratooning the plant crop based on monthly cut outs over a 3–4-month ratooning period with vacant plant positions replanted during ratooning

Growth and yield of 3 hybrid papayas (Carica papaya L.) under mulched and bare ground conditions

At Yarwun (151.3˚E, 23.75˚S), Australia, papaya Hybrid 29 yielded twice as much fruit as Hybrid 11 and 30% more than Hybrid 13. The plots mulched with coarse grass hay yielded 50% more fruit than the plots with bare ground. The highest yielding treatment, Hybrid 29 + mulch, averaged the equivalent of 81 t/ha.year over the 16.5-month harvest period. The yields were achieved in spite of inadequate water supply due to drought and the loss of 877 plants from 1441 plant positions (4 plants per position) due to the 3 phytoplasma diseases; dieback, yellow crinkle and mosaic. Hybrid 29 produced higher yields than the other hybrids by flowering early on shorter plants with thicker stems and setting more fruit that commenced lower down on the stem. Hybrid 13 was intermediate in size and the amount of fruit setting between Hybrid 29 and Hybrid 11 but was the slowest to flower and set fruit. Hybrid 11 had the thinnest and tallest stems, flowered at an intermediate time between the other 2 hybrids and produced fewer flowers and fruit resulting in the lowest yield. Mulching increased stem height and thickness, promoted earlier flowering and increased fruit set, yield and average fruit weigh

The Effect of Pravastatin on Intima Media Thickness of the Carotid Artery in Patients with Normal Cholesterol

AbstractObjectiveCarotid intima media thickness (IMT) is a good indicator of the severity of atherosclerotic disease. Statins have been found to reduce carotid IMT in patients with hypercholesterolaemia. The aim of this study was to investigate if pravastatin is effective in reducing IMT in normocholesterolaemic patients with carotid artery disease.MethodsPatients with carotid artery stenosis and normal cholesterol levels who were not on a statin, were recruited. Patients were randomised to receive pravastatin or placebo daily. Serum concentration of cholesterol and IMT of common carotid arteries were measured before randomisation and at 3 monthly intervals thereafter, for 9 months. IMT was analysed to give the mean of a standardised 2cm of the common carotid artery (CCA). Results are expressed as median (IQR) and comparison made using the Wilcoxon signed ranks test.ResultsFifty-four patients were examined. Twenty-eight patients were randomised to active treatment. There was no difference in demographic details and co-morbid states between the two groups. A significant reduction in cholesterol concentration was observed from 3 months in patients randomised to the pravastatin group [5.14(4.72–5.88) vs. 4.11(3.44–5.33), p<0.05], while there was also a significant decrease in combined IMT form 6 months [1.53(1.36–1.87) vs. 1.41 (1.33–1.78), p<0.05].ConclusionsThe results demonstrate that pravastatin reduces intima media thickness of the common carotid artery in normocholesterolaemic patients with moderate carotid stenosis

Inter-rater reliability of the EPUAP pressure ulcer classification system using photographs

Background. Many classification systems for grading pressure ulcers are discussed in the literature. Correct identification and classification of a pressure ulcer is important for accurate reporting of the magnitude of the problem, and for timely prevention. The reliability of pressure ulcer classification systems has rarely been tested. Aims and objectives. The purpose of this paper is to examine the inter-rater reliability of classifying pressure ulcers according to the European Pressure Ulcer Advisory Panel classification system when using pressure ulcer photographs.Design. Survey was among pressure ulcer experts.Methods. Fifty-six photographs were presented to 44 pressure ulcer experts. The experts classified the lesions as normal skin, blanchable erythema, pressure ulcer (four grades) or incontinence lesion. Inter-rater reliability was calculated.Results. The multirater-Kappa for the entire group of experts was 0.80 (P &lt; 0.001).Various groups of experts obtained comparable results. Differences in classifications are mainly limited to 1 degree of difference. Incontinence lesions are most often confused with grade 2 (blisters) and grade 3 pressure ulcers (superficial pressure ulcers).Conclusions. The inter-rater reliability of the European Pressure Ulcer Advisory Panel classification appears to be good for the assessment of photographs by experts. The difference between an incontinence lesion and a blister or a superficial pressure ulcer does not always seem clear.Relevance to clinical practice. The ability to determine correctly whether a lesion is a pressure ulcer lesion is important to assess the effectiveness of preventive measures. In addition, the ability to make a correct distinction between pressure ulcers and incontinence lesions is important as they require different preventive measures. A faulty classification leads to mistaken measures and negative results. Photographs can be used as a practice instrument to learn to discern pressure ulcers from incontinence lesions and to get to know the different grades of pressure ulcers. The Pressure Ulcer Classification software package has been developed to facilitate learning

Associations between blood sex steroid concentrations and risk of major adverse cardiovascular events in healthy older women in Australia: a prospective cohort substudy of the ASPREE trial

Background: Blood testosterone concentrations in women decline during the reproductive years and reach a nadir in the seventh decade, after which concentrations increase and are restored to those of reproductive-aged women early in the eighth decade. We aimed to establish the association between the concentration of testosterone in the blood and risk of major adverse cardiovascular events (MACE) and all-cause mortality in healthy older women. Methods: SHOW was a prospective cohort substudy of the longitudinal randomised ASPREE trial. Eligible participants were women aged at least 70 years from Australia with unimpaired cognition, no previous MACE, and a life expectancy of at least 5 years. Participants who were receiving hormonal or steroid therapy were ineligible for inclusion. We measured serum concentrations of sex steroids with liquid chromatography–tandem mass spectrometry and of SHBG with immunoassay. We compared lower concentrations of sex hormones with higher concentrations using four quartiles. Primary endpoints were risk of MACE and all-cause mortality, the associations of which with sex steroid concentrations were assessed using Cox proportional hazards regression that included age, body-mass index, smoking status, alcohol consumption, diabetes, hypertension, dyslipidaemia, impaired renal function, and treatment allocation in the ASPREE trial (aspirin vs placebo). ASPREE is registered with ClinicalTrials.gov, NCT01038583. Findings: Of the 9180 women recruited to the ASPREE trial between March 10, 2010, and Dec 31 2014, 6358 participants provided sufficient biobank samples at baseline and 5535 were included in the final analysis. Median age at entry was 74·0 years (IQR 71·7–77·7). During a median 4·4 years of follow-up (24 553 person-years), 144 (2·6%) women had a first MACE (incidence 5·9 per 1000 person-years). During a median 4·6 years of follow-up (3·8–5·6), 200 women died (7·9 per 1000 person-years). In the fully adjusted models, higher concentrations of testosterone were associated with a lower incidence of MACE (quartile 4 vs quartile 1: hazard ratio 0·57 [95% CI 0·36–0·91]; p=0·02), as were higher concentrations of DHEA (quartile 4 vs quartile 1: 0·61 [0·38–0·97]; p=0·04). For oestrone, a lower risk of MACE was seen for concentrations in quartile 2 only, compared with quartile 1 (0·55 [0·33–0·92]; p=0·02). In fully adjusted models, no association was seen between SHBG and MACE, or between any hormone or SHBG and all-cause mortality. Interpretation: Blood concentrations of testosterone and DHEA above the lowest quartile in older women were associated with a reduced risk of a first-ever MACE. Given that the physiological effects of DHEA are mediated through its steroid metabolites, if the current findings were to be replicated, trials investigating testosterone therapy for the primary prevention of ischaemic cardiovascular disease events in older women would be warranted. Funding: The National Health and Medical Research Council of Australia, US National Institute on Aging, the Victorian Cancer Agency, the Commonwealth Scientific and Industrial Research Organisation, and Monash University