A review of the adaptive significance and ecosystem consequences of zooplankton diel vertical migrations

Diel vertical migration (DVM) by zooplankton is a universal feature in all the World's oceans, as well as being common in freshwater environments. The normal pattern involves movement from shallow depths at night to greater depths during the day. For many herbivorous and omnivorous mesozooplankton that feed predominantly near the surface on phytoplankton and microzooplankton, minimising the risk of predation from fish seems to be the ultimate factor behind DVM. These migrants appear to use deep water as a dark daytime refuge where their probability of being detected and eaten is lower than if they remained near the surface. Associated with these vertical movements of mesozooplankton, predators at higher trophic levels, including invertebrates, fish, marine mammals, birds and reptiles, may modify their behaviour to optimise the exploitation of their vertically migrating prey. Recent advances in biotelemetry promise to allow the interaction between migrating zooplankton and diving air-breathing vertebrates to be explored in far more detail than hitherto.

The functional significance of ventilation frequency, and its relationship to oxygen demand in the resting brown long-eared bat, Plecotus auritus

Mean oxygen consumption and simultaneous ventilation frequency of nine non-reproductive brown long-eared bats (body mass 8.53–13.33 g) were measured on 159 occasions. Ambient (chamber) temperature at which the measurements were made ranged from 10.8 to 41.1°C. Apneic ventilation occurred in 22 of the 59 measurements made when mean oxygen consumption was less than 0.5 ml·min-1. No records of apneic ventilation were obtained when it was over 0.5 ml·min-1. The relationship between ventilation frequency and mean oxygen consumption depended on whether ventilation was apneic or non-apneic. When ventilation was non-apneic the relationship was positive and log-linear. When ventilation was apneic the relationship was log-log. Within the thermoneutral zone ventilation frequency was not significantly different from that predicted from allometric equations for a terrestrial mammal of equivalent body mass, but was significantly greater than that predicted for a bird. A reduction in the amount of oxygen consumed per breath occurred at ambient temperatures above the upper critical temperature (39°C).

When surfacers do not dive : multiple significance of extended surface times in marine turtles

Marine turtles spend more than 90% of their life underwater and have been termed surfacers as opposed to divers. Nonetheless turtles have been reported occasionally to float motionless at the surface but the reasons for this behaviour are not clear. We investigated the location, timing and duration of extended surface times (ESTs) in 10 free-ranging loggerhead turtles (Caretta caretta) and the possible relationship to water temperature and diving activity recorded via satellite relay data loggers for 101–450 days. For one turtle that dived only in offshore areas, ESTs contributed 12% of the time whereas for the other turtles ESTs contributed 0.4–1.8% of the time. ESTs lasted on average 90 min but were mostly infrequent and irregular, excluding the involvement of a fundamental regulatory function. However, 82% of the ESTs occurred during daylight, mostly around noon, suggesting a dependence on solar radiation. For three turtles, there was an appreciable (7°C to 10.5°C) temperature decrease with depth for dives during periods when ESTs occurred frequently, suggesting a re-warming function of EST to compensate for decreased body temperatures, possibly to enhance digestive efficiency. A positive correlation between body mass and EST duration supported this explanation. By contrast, night-active turtles that exceeded their calculated aerobic dive limits in 7.6–16% of the dives engaged in nocturnal ESTs, probably for lactate clearance. This is the first evidence that loggerhead turtles may refrain from diving for at least two reasons, either to absorb solar radiation or to recover from anaerobic activity.

A dish-rack full of crockery : social significance and the Sydney Opera House

The sculptural roof forms of the Sydney Opera House regularly attract visual analogies in the public mind. Although they are mostly referred to as a??sailsa?? or a??shellsa?? they have also been described through humorous metaphors like a??a dishrack full of crockerya??. This particular visual pun, is a reference to a linocut by Eric Thake, produced in 1972, the year before the official opening of the Sydney Opera House. This analogy and its continued popularity to date evidences the social and cultural life of this building. Much of the scholarly on the Sydney Opera House investigates the architecture and the circumstances of its realisation, whilst its reception and social significance, has received little systematic attention. Through Thakea??s linocut, the paper discusses the current limitations in evaluating social significance in an Australian heritage context and proposes an alternative perspective to this problem through two scholars who bring a??subjective experiencea?? to bear on the production of meaning. For Gillian Rose, visual artefacts become significant through their embodied experience, whilst Ann Game argues for the inclusion of such usually-excluded subjects like desire, memory, time and the body in the construction of meaning. By bringing these theories to bear on a specific example - Eric Thakea??s visual metaphor for the Sydney Opera House - the paper investigates a new approach to social significance.

The principle of legality as clear statement rule: significance and problems

In Australia, the common law principle of legality has hardened into a strong clear statement rule that is applied when legislation engages common law rights and freedoms. It has transformed a loose collection of rebuttable interpretive presumptions into a quasi-constitutional common law bill of rights. However, these developments are not without controversy or issue. The analysis undertaken in this article suggests that the principle of legality as clear statement rule -- as mandated by the High Court in Coco v The Queen -- can only work legitimately if Parliament has clear and prior notice of the rights and freedoms that it operates to protect. But it is problematic if what a common law right, such as freedom of speech, requires or guarantees in any given legislative context is unclear and contested, and so must be judicially divined at the point of application. In these cases, the principle operates to enforce a (post-legislative) judicial approximation of what best protects and promotes an abstract legal value or principle. It amounts to the illegitimate judicial remaking of prior legislative decisions on rights. This undercuts the normative justifications for the principle of legality as it obscures from Parliament the common law (rights) backdrop against which its legislation is enacted and interpreted.

The significance of northern-central Bass Strait in south-eastern Australia as habitat for burrowing seabirds

The present study provides the first complete estimate of the abundance and distribution of burrowing seabirds in northern-central Bass Strait, a key region for breeding seabirds in south-eastern Australia. The estimated total number of breeding burrows in the region in 2008-11 were 755300±32400 (s.e.) burrows of Short-tailed Shearwaters (Ardenna tenuirostris), 26700±3500 of Little Penguins (Eudyptula minor), 19100±2200 of Common Diving-Petrels (Pelecanoides urinatrix) and 4200±2700 of Fairy Prions (Pachyptila turtur). These represent substantial proportions of the total estimated Australian breeding populations of these species: 6% of the total population of Short-tailed Shearwaters, 14% of Little Penguins, 0.4% of Fairy Prions and 13% of Common Diving-Petrels. Based on the number of active burrows, the number of breeding Short-tailed Shearwaters in the region is estimated to have decreased 35% between 1978-80 and 2008-11, equivalent to a decrease of 1.4% per annum between 1980 and 2011. The regional population of Little Penguins, however, appears to have increased substantially over the same period. Identification of population trends of the other species is limited by a lack of previous data. The importance of this area for burrowing seabirds and the substantial decline in numbers of Short-tailed Shearwaters warrants more frequent monitoring of the abundance of seabirds in the region to allow a robust comparison of changes in populations over time as well as the identification of possible causative factors. © BirdLife Australia 2014.

Power, effects, confidence, and significance: an investigation of statistical practices in nursing research

Objectives: To (a) assess the statistical power of nursing research to detect small, medium, and large effect sizes; (b) estimate the experiment-wise Type I error rate in these studies; and (c) assess the extent to which (i) a priori power analyses, (ii) effect sizes (and interpretations thereof), and (iii) confidence intervals were reported. Design: Statistical review. Data sources: Papers published in the 2011 volumes of the 10 highest ranked nursing journals, based on their 5-year impact factors. Review methods: Papers were assessed for statistical power, control of experiment-wise Type I error, reporting of a priori power analyses, reporting and interpretation of effect sizes, and reporting of confidence intervals. The analyses were based on 333 papers, from which 10,337 inferential statistics were identified. Results: The median power to detect small, medium, and large effect sizes was .40 (interquartile range [. IQR]. = .24-.71), .98 (IQR= .85-1.00), and 1.00 (IQR= 1.00-1.00), respectively. The median experiment-wise Type I error rate was .54 (IQR= .26-.80). A priori power analyses were reported in 28% of papers. Effect sizes were routinely reported for Spearman's rank correlations (100% of papers in which this test was used), Poisson regressions (100%), odds ratios (100%), Kendall's tau correlations (100%), Pearson's correlations (99%), logistic regressions (98%), structural equation modelling/confirmatory factor analyses/path analyses (97%), and linear regressions (83%), but were reported less often for two-proportion z tests (50%), analyses of variance/analyses of covariance/multivariate analyses of variance (18%), t tests (8%), Wilcoxon's tests (8%), Chi-squared tests (8%), and Fisher's exact tests (7%), and not reported for sign tests, Friedman's tests, McNemar's tests, multi-level models, and Kruskal-Wallis tests. Effect sizes were infrequently interpreted. Confidence intervals were reported in 28% of papers. Conclusion: The use, reporting, and interpretation of inferential statistics in nursing research need substantial improvement. Most importantly, researchers should abandon the misleading practice of interpreting the results from inferential tests based solely on whether they are statistically significant (or not) and, instead, focus on reporting and interpreting effect sizes, confidence intervals, and significance levels. Nursing researchers also need to conduct and report a priori power analyses, and to address the issue of Type I experiment-wise error inflation in their studies. © 2013 .

Malnutrition: significance, prevalence and management of the hospitalised surgery patient

Malnutrition is prevalent and poorly diagnosed in hospitalised patients, with high rates of malnutrition seen in surgical patients. The administration of a specialised immuno-nutrition supplement is beneficial for malnourished patients undergoing gastrointestinal surgery, and a multidisciplinary team approach improves nutritional care for patients.