In non-destructive evaluation guided wave inspections, the elastic structure to be inspected is often embedded within other elastic media and the ensuing leaky waves are complex and non-trivial to compute; we consider the canonical example of an elastic waveguide surrounded by other elastic materials that demonstrates the fundamental issues with calculating the leaky waves in such systems. Due to the complex wavenumber solutions required to represent them, leaky waves pose significant challenges to existing numerical methods, with methods that spatially discretise the field to retrieve them suffering from the exponential growth of their amplitude far into the surrounding media. We present a spectral collocation method yielding an accurate and efficient identification of these modes, leaking into elastic half-spaces.
View Article and Find Full Text PDFA recent publication in Nature by Arnould et al. describes a novel chromatin compartment, termed "damaged" or "D compartment," that facilitates the repair of DNA double-strand breaks but also increases the risk of potentially oncogenic translocation formation.
View Article and Find Full Text PDFAssay for transposase-accessible chromatin (ATAC) and chromatin immunoprecipitation (ChIP), coupled with next-generation sequencing (NGS), have revolutionized the study of gene regulation. A lack of standardization in the analysis of the highly dimensional datasets generated by these techniques has made reproducibility difficult to achieve, leading to discrepancies in the published, processed data. Part of this problem is due to the diverse range of bioinformatic tools available for the analysis of these types of data.
View Article and Find Full Text PDFNon-communicable diseases (NCDs), including coronary heart disease, stroke, hypertension, type 2 diabetes, dementia, depression and cancers, are on the rise worldwide and are often associated with a lack of physical activity (PA). Globally, the levels of PA among individuals are below WHO recommendations. A lack of PA can increase morbidity and mortality, worsen the quality of life and increase the economic burden on individuals and society.
View Article and Find Full Text PDFBiofouling of ships' internal seawater systems (ISS) can cause significant operational issues and is a potential transfer mechanism for marine nonindigenous species. This study used an engine room simulator and economic evaluation to quantify impacts on commercial ship performance of biofouling occlusion within various ISS nodes (sea chest, strainer, and heat exchangers). A characteristic hockey-stick relationship between occlusion and impact emerged, whereby engine room systems could tolerate up to 55% occlusion of a single node without operational impact, followed by rapid performance deterioration.
View Article and Find Full Text PDFLeaky waves are an important class of waves, particularly for guiding waves along structures embedded within another medium; a mismatch in wavespeeds often leads to leakage of energy from the waveguide, or interface, into the medium, which consequently attenuates the guided wave. The accurate and efficient identification of theoretical solutions for leaky waves is a key requirement for the choices of modes and frequencies required for non-destructive evaluation inspection techniques. We choose a typical situation to study: an elastic waveguide with a fluid on either side.
View Article and Find Full Text PDFOstreid herpesvirus 1 (OsHV-1) has caused mass mortalities in Pacific oysters () in Europe, Australia, and New Zealand. While aquaculture-associated movements of infected Pacific oysters are a well-known cause of OsHV-1 spread once established in a region, translocation biofouling of aquaculture equipment or vessels needs further investigation to explain the more distant spread of OsHV-1. Laboratory experiments were designed to test for transmission of OsHV-1 between infected and naïve Pacific oysters a simulated biofouling translocation scenario.
View Article and Find Full Text PDFMammalian gene expression patterns are controlled by regulatory elements, which interact within topologically associating domains (TADs). The relationship between activation of regulatory elements, formation of structural chromatin interactions and gene expression during development is unclear. Here, we present Tiled-C, a low-input chromosome conformation capture (3C) technique.
View Article and Find Full Text PDFA PCR protocol was optimised and validated for the detection of viable Tenacibaculum maritimum cells in salmon skin tissue. Viability conventional (vPCR) and quantitative PCR (v-qPCR) assays both had a limit of detection of 10 CFU mL viable cells. The v-qPCR assay showed a linear quantification over 4 log units.
View Article and Find Full Text PDFBiofouled commercial and recreational vessels are primary vectors for the introduction and spread of marine non-indigenous species (NIS). This study designed and assessed a portable system to reactively treat biofouling in the internal pipework of recreational vessels - a high-risk 'niche area' for NIS that is difficult to access and manage. A novel thermal treatment apparatus was optimised in a series of laboratory experiments performed using scale models of vessel pipework configurations.
View Article and Find Full Text PDFInvasive non-indigenous species (NIS) are a threat to marine biodiversity and marine reliant industries. Recreational vessels are recognised as an important vector of NIS translocation, particularly domestically. This paper reports on a novel application of multilevel modelling and multiple imputation in order to quantify the relationship between biofouling biomass (wet weight) and the vessel-level characteristics of recreational and fishing vessels.
View Article and Find Full Text PDFWhile the influence of nature (genes) and nurture (environment) on elite sporting performance remains difficult to precisely determine, the dismissal of either as a contributing factor to performance is unwarranted. It is accepted that a complex interaction of a combination of innumerable factors may mold a talented athlete into a champion. The prevailing view today is that understanding elite human performance will require the deciphering of two major sources of individual differences, genes and the environment.
View Article and Find Full Text PDFNaphthalene makes up a substantial fraction of polycyclic aromatic hydrocarbons (PAHs) in crude oil and is an important by-product of industry; however, few studies have investigated the toxicity of naphthalene to aquatic organisms. We examined the toxicity of increasing concentrations (0, carrier control, 130, 200 and 400microg/l) of naphthalene to adult rainbowfish (Melanotaenia fluviatilis) for 3 and 14 days to determine its potential to act as an endocrine disruptor. After exposure for 3 days, no changes in sex steroids were measured.
View Article and Find Full Text PDFFew studies have investigated the potential reproductive effects of toxicants on Australian freshwater fish species. The present study uses the Australian rainbowfish (Melanotaenia fluviatilis) as a model for testing the potential effects of 17beta-estradiol. Groups of reproductively active rainbowfish were exposed to waterborne 17beta-estradiol (control, carrier control, and 30, 100, 300, and 1,000 ng/L) for 3- and 14-d periods.
View Article and Find Full Text PDFComp Biochem Physiol C Toxicol Pharmacol
April 2007
Concentrations of the essential trace metals copper and zinc were measured in the pyloric caeca of female Coscinasterias muricata sampled from Port Phillip Bay, Victoria, Australia at monthly intervals for 15 months. Results indicate that the concentrations of these metals appear to be regulated by the reproductive cycle. Peaks in zinc concentration occurred simultaneously with peaks in progesterone concentration in the pyloric caeca.
View Article and Find Full Text PDFThis study examined the effects of caffeine, co-ingested with a high fat meal, on perceptual and metabolic responses during incremental (Experiment 1) and endurance (Experiment 2) exercise performance. Trained participants performed three constant-load cycling tests at approximately 73% of maximal oxygen uptake (VO2max) for 30 min at 20 degrees C (Experiment 1, n = 8) and to the limit of tolerance at 10 degrees C (Experiment 2, n = 10). The 30 min constant-load exercise in Experiment 1 was followed by incremental exercise (15 W .
View Article and Find Full Text PDFLevels of cytochrome P450 enzymes were measured in pyloric caeca microsomes of the asteroid Coscinasterias muricata following exposure to sediment with nominal concentrations of 0, 0.1 or 2 ml crude oil kg(-1) (dry weight) and subsequent depuration. No significant differences were observed in total cytochrome P450 levels or cytochrome P418 levels following the exposure period.
View Article and Find Full Text PDFComp Biochem Physiol B Biochem Mol Biol
March 2005
Previous studies have hypothesised that mitochondrial DNA (mtDNA) polymorphisms may influence aerobic performance. The matrilineal inheritance and accumulation of polymorphisms in mtDNA means that mtDNA haplogroups, characterised by key polymorphisms, are often represented at different frequencies in different populations. The present study aimed to compare the mtDNA haplogroup distribution of elite Ethiopian athletes relative to the general Ethiopian population.
View Article and Find Full Text PDFFavourable genetic endowment has been proposed as part of the explanation for the success of East African endurance athletes, but no evidence has yet been presented. The Y chromosome haplogroup distribution of elite Ethiopian athletes (n=62) was compared with that of the general Ethiopian population (n=95) and a control group from Arsi (a region producing a disproportionate number of athletes; n=85). Athletes belonged to three groups: marathon runners (M; n=23), 5-km to 10-km runners (5-10K; n=21) and other track and field athletes (TF; n=18).
View Article and Find Full Text PDFThe effects of creatine (Cr) supplementation on cardiovascular, metabolic, and thermoregulatory responses, and on the capacity of trained humans to perform prolonged exercise in the heat was examined. Endurance-trained males (n = 21) performed 2 constant-load exercise tests to exhaustion at 63 +/- 5 % VO(2max) in the heat (ambient temperature: 30.3 +/- 0.
View Article and Find Full Text PDFBody mass index (BMI) distribution changes were assessed in 2547 relatively affluent English girls, aged 12-16 years, during the UK childhood obesity epidemic (1986-96). An increase in BMI variability was observed only in 12-14 year olds, suggesting that BMI changes for population subgroups were complex, and inconsistent with a generalised increase in BMI.
View Article and Find Full Text PDFIntroduction: The dominance of East-African athletes in distance running remains largely unexplained; proposed reasons include favorable genetic endowment and optimal environmental conditions.
Purpose: To compare the demographics of elite Ethiopian athletes with the general Ethiopian population and assess the validity of reports linking running long distances to school with endurance success.
Methods: Questionnaires, administered to 114 members (male and female) of the Ethiopian national athletics team and 111 Ethiopian control subjects (C) obtained information on place of birth, language, distance and method of travel to school.
Considerable evidence points towards a prominent role for central nervous system (CNS) mechanisms in the pathogenesis of chronic fatigue syndrome (CFS), a disorder characterized chiefly by persistent, often debilitating, fatigue. We wished to characterize circulating profiles of putative amino acid modulators of CNS 5-hydroxytryptamine (5-HT; serotoninergic) and dopaminergic function in CFS patients at rest, as well as during symptom-limited exercise and subsequent recovery. Groups of 12 CFS patients and 11 age- and sex-matched sedentary controls, with similar physical activity histories, underwent ramp-incremental exercise to the limit of tolerance.
View Article and Find Full Text PDFThe present study examines the impact of exposure to oil-derived products on the behaviour and physiology of the Australian 11-armed asteroid Coscinasterias muricata. Asteroids were exposed to dilutions of water-accommodated fraction (WAF) of Bass Strait stabilised crude oil, dispersed oil or burnt oil (n = 8) for 4 days whereby, prey-localisation behaviour was examined immediately after exposure, and following 2, 7, and 14 days depuration in clean seawater. The prey-localisation behaviour of asteroids exposed to WAF and dispersed oil was significantly affected though recovery was apparent following 7 and 14 days depuration, respectively.
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