Are nurses the key to the increased uptake of frequent nocturnal home haemodialysis in Australia?

Background: Although there are significant benefits to frequent nocturnal home haemodialysis (NHHD) there has been a low acceptance of this therapy in Australia.

Aim: The aim of this paper is to explore and discuss the literature relating to the nursing barriers to frequent nocturnal home haemodialysis.

Methods: A search of nursing, medical, social work and psychological literature was performed.

Results: Nurses are key contributors to the increase of NHHD within the dialysis population. Knowledge, culture and nurse satisfaction are key areas to address to increase NHHD uptake.

Conclusion: Nurses need to challenge the cultural and organisational barriers that are preventing further uptake of NHHD. If nurses do not we cannot claim to be helping patients attain their best possible outcome.

The effect of artificial night light on the abundance of nocturnal birds

Urbanisation is increasing rapidly, impacting on a broad range of species. The proliferation of electric light has transformed the night time environment; however, our understanding on the effects of artificial night lighting on fauna, including nocturnal birds, is extremely limited. The aim ofthis research was to determine whether artificial night light affected the abundance of nocturnal birds. Spotlighting surveys were undertaken in Research Park, Melbourne, Victoria, along three 300 m transects. Each transect was surveyed five times during three light treatments: when lights were on, 20 minutes after lights were turned off and when lights were absent, over a period often nights. A total of 123 nocturnal birds was detected during survey nights. Two species were recorded - the Southern Boobook Ninox novaeseelandiae and the Tawny Frogmouth Podargus strigoides. The Tawny Frogmouth was detected along all three transects (n=121); however, the Southern Boobook was detected along one transect only (n=2). None of the light treatments had a significant effect on bird abundance. Neither did location, habitat or the combined effects of light treatments, location and habitat. The results of this research will contribute to a growing body of knowledge and support future conservation activities for species in areas undergoing urbanisation. {The Victorian Naturalist 127 (5) 2010, 192-195).

Interplay among nocturnal activity, melatonin, corticosterone and performance in the invasive cane toad (Rhinella marinus)

Most animals conduct daily activities exclusively either during the day or at night. Here, hormones such as melatonin and corticosterone, greatly influence the synchronization or regulation of physiological and behavioral cycles needed for daily activity. How then do species that exhibit more flexible daily activity patterns, responses to ecological, environmental or life-history processes, regulate daily hormone profiles important to daily performance? This study examined the consequences of (1) nocturnal activity on diel profiles of melatonin and corticosterone and (2) the effects of experimentally increased acute melatonin levels on physiological and metabolic performance in the cane toad (Rhinella marinus). Unlike inactive captive toads that had a distinct nocturnal melatonin profile, nocturnally active toads sampled under field and captive conditions, exhibited decreased nocturnal melatonin profiles with no evidence for any phase shift. Nocturnal corticosterone levels were significantly higher in field active toads than captive toads. In toads with experimentally increased melatonin levels, plasma lactate and glucose responses following recovery post exercise were significantly different from control toads. However, exogenously increased melatonin did not affect resting metabolism in toads. These results suggest that toads could adjust daily hormone profiles to match nocturnal activity requirements, thereby avoiding performance costs induced by high nocturnal melatonin levels. The ability of toads to exhibit plasticity in daily hormone cycles, could have broad implications for how they and other animals utilize behavioral flexibility to optimize daily activities in response to natural and increasingly human mediated environmental variation.

Adaptation to urban environments promotes high reproductive success in the tawny frogmouth (Podargus strigoides), an endemic nocturnal bird species

The tawny frogmouth (Podargus strigoides) is an endemic, nocturnal bird species widespread throughout Australia with high numbers in urban environments but very limited information exists on its ability to cope with urban systems. We investigated the reproductive behaviour of this species in response to a continuum of urbanisation. Firstly, we asked does the degree of urbanisation influence the availability of suitable nesting locations. Secondly, does broad and/or local scale factors surrounding a nest influence reproductive success? And finally, does the degree of urbanisation influence time of breeding? We located 158 nest sites and monitored 189 breeding attempts across four breeding seasons (2010-2013). One hundred and thirty three of these attempts successfully fledged 177 chicks. We categorized 75 attempts as first known attempts for that season resulting in 77 fledged chicks. In some pairs, repeated attempts occurred after failure. We observed double brooding by three pairs, a strategy largely unknown in this species. Spatial modelling revealed that birds selected more vegetated areas of the gradient within which to locate their nests, avoiding more highly urbanized areas. We identified no association between land-use type and breeding success at both broad and local scales. Birds selected native rough-barked Eucalyptus tree species more frequently than other trees for nesting. The key drivers for the commencement of breeding were climatic variables, in particular rainfall. The ability of the species to synchronize breeding attempts to coincide with optimal environmental conditions resulted in extremely high reproductive success suggesting high individual fitness and an adaptation to local environmental conditions.

If waterbirds are nocturnal are we conserving the right habitats?

Waterbirds are key indicators of wetland health and recent declines in their abundance have renewed focus on conservation of their habitats in Australia. Yet conservation efforts have mostly ignored the identification of habitats used at night. In this study we assessed three common species, Grey Teal (Anas gracilis), Chestnut Teal (Anas castanea) and Australian Wood Duck (Chenonetta chubata), during day and night. Thermal imaging technologies were utilised to identify individuals to species, count abundances and observe habitat requirements. We found major differences in abundance between night and day of all three species at our study sites. Further, habitat use of teals differed between nocturnal and diurnal hours, with birds aggregating on the bank during daylight hours and moving onto the water during the night. Our findings suggest that nocturnal waterbird surveys can assist conservation efforts. By monitoring bird numbers by night, the significance of a habitat for feeding and shelter purposes can be determined. Additionally, by studying nocturnal behaviour and habitat use, identification and conservation of important wetlands will be increased.

How well do ecosystem-based planning units represent different componenets of biodiversity?

There are many proposals for managing biodiversity by using surrogates, such as umbrella, indicator, focal, and flagship species. We use the term biodiversity management unit for any ecosystem-based classificatory scheme for managing biodiversity. The sufficiency of biodiversity management unit classification schemes depends upon (1) whether different biotic elements (e.g., trees, birds, reptiles) distinguish between biodiversity management units within a classification (i.e., coherence within classes}; and (2) whether different biotic elements agree upon similarities and dissimilarities among biodiversity management unit classes (i.e., conformance among classes). Recent evaluations suggest that biodiversity surrogates based on few or single taxa are not useful. Ecological vegetation classes are an ecosystem-based classification scheme used as one component for biodiversity management in Victoria, Australia. Here we evaluated the potential for ecological vegetation classes to be used as biodiversity management units in the box-ironbark ecosystem of central Victoria, Australia. Eighty sites distributed among 14 ecological vegetation classes were surveyed in the same ways for tree species, birds, mammals, reptiles, terrestrial invertebrates, and nocturnal flying insects. Habitat structure and geographic separations also were measured, which, with the biotic elements, are collectively referred to as variables. Less than half of the biotic element-ecological vegetation class pairings were coherent. Generalized Mantel tests were used to examine conformance among variables with respect to ecological vegetation classes. While most tests were not significant, birds, mammals, tree species, and habitat structure together showed significant agreement on the rating of similarities among ecological vegetation classes. In this system, use of ecological vegetation classes as biodiversity management units may account reasonably well for birds, mammals, and trees; but reptiles and invertebrates would not be accommodated. We conclude that surrogates will usually have to be augmented or developed as hierarchies to provide general representativeness.

Are day-active small mammals rare and small birds abundant in Australian desert environments because small mammals are inferior thermoregulators?

Small desert birds are typically diurnal and highly mobile (hence conspicuous) whereas small non-volant mammals are generally nocturnal and less mobile (hence inconspicuous). Birds are more mobile than terrestrial mammals on a local and geographic scale, and most desert birds are not endemic but simply move to avoid the extremes of desert conditions. Many small desert mammals are relatively sedentary and regularly use physiological adjustments to cope with their desert environment (e.g., aestivation or hibernation). It seems likely that prey activity patterns and reduced conspicuousness to predators have reinforced nocturnality in small desert mammals. Differences such as nocturnality and mobility simply reflect differing life-history traits of birds and mammals rather than being a direct result of their differences in physiological capacity for tolerating daytime desert conditions.

Novel genes in the liver of diabetic Psammomys obesus

Type 2 diabetes mellitus is a metabolic disease characterised by defects in insulin secretion and insulin action and disturbances in carbohydrate, fat and protein metabolism. Hepatic insulin resistance contributes to hyperglycemia and also leads to disturbances in fat metabolism in type 2 diabetes. Psammomys obesus is a unique poly genie animal model of type 2 diabetes and obesity, ideally suited for studies examining physiological and genetic aspects of these diseases. To identify metabolic abnormalities potentially contributing to the obesity and diabetes phenotype in P. obesus, indirect calorimetry was used to characterise whole body energy expenditure and substrate utilisation. Lean-NGT, obese-IGT and obese-diabetic animals were examined in fed and fasted states and following 14 days of dietary energy restriction. Energy expenditure and fat oxidation were elevated in the obese-IGT and obese-diabetic groups in proportion to body weight. Glucose oxidation was not different between groups. Obese-diabetic P. obesus displayed elevated nocturnal blood glucose levels and fat oxidation. Following 14 days of dietary energy restriction, body weight was reduced and plasma insulin and blood glucose levels were normalised in all groups. Glucose oxidation was reduced and fat oxidation was increased. After 24 hours of fasting, plasma insulin and blood glucose levels were normalised in all groups. Energy expenditure and glucose oxidation were greatly reduced and fat oxidation was increased. Following either dietary energy restriction or fasting, energy expenditure, glucose oxidation and fat oxidation were not different between groups of P. obesus. Energy expenditure and whole body substrate utilisation in P. obesus was similar to that seen in humans. P. obesus responded normally to short term fasting and dietary energy restriction. Elevated nocturnal fat oxidation rates and plasma glucose levels in obese-diabetic P. obesus may be an important factor in the pathogenesis of obesity and type 2 diabetes in these animals. These studies have further validated P. obesus as an ideal animal model of type 2 diabetes and obesity. It was hypothesised that many genes in the liver of P. obesus involved in glucose and fat metabolism would be differentially expressed between lean-NGT and obese-diabetic animals. These genes may represent significant factors in the pathophysiology of type 2 diabetes. Two gene discovery experiments were conducted using suppression subtractive hybridisation (SSH) to enrich a cDNA library for differentially expressed genes. Experiment 1 used cDNA dot blots to screen 576 clones with cDNA derived from lean-NGT and obese-diabetic animals. 6 clones were identified as overexpressed in lean-NGT animals and 6 were overexpressed in obese-diabetic animals. These 12 clones were sequenced and SYBR-Green PCR was used to confirm differential gene expression. 4 genes were overexpressed (≥1.5 fold) in lean-NGT animals and 4 genes were overexpressed (≥1.5 fold) in obese-diabetic animals. To explore the physiological role of these genes, hepatic gene expression was examined in several physiological conditions. One gene, encoding thyroxine binding globulin (TBG), was confirmed as overexpressed in lean-NGT P. obesus with ad libitum access to food, relative to both obese-IGT and obese-diabetic animals. TBG expression decreased with fasting in all animals. Fasting TBG expression remained greater in lean-NGT animals than obese-IGT and obese-diabetic animals. TBG expression was not significantly affected by dietary energy restriction. TBG is involved in thyroid metabolism and is potentially involved in the regulation of energy expenditure. Fasting increased hepatic site 1 protease (SIP) expression in lean-NGT animals but was not significantly affected in obese-IGT and obese-diabetic animals. SIP expression was not significantly affected by dietary energy restriction. SIP is involved in the proteolytic processing of steroid response element binding proteins (SREBP). SREBPs are insulin responsive and are known to be involved in lipid metabolism. Gene expression studies found TBG and SIP were associated with obesity and diabetes. Future research will determine whether TBG and SIP are important in the pathogenesis of these diseases. Experiment 2 used SSH and cDNA microarray to screen 8064 clones. 223 clones were identified as overexpressed in lean-NGT P. obesus and 274 clones were overexpressed in obese-diabetic P. obesus (p ≤0.05). The 9 most significantly differentially expressed clones identified from the microarray screen were sequenced (p ≤0.01). 7 novel genes were identified as well as; sulfotransferase related protein and albumin. These 2 genes have not previously been associated with either type 2 diabetes or obesity. It is unclear why hepatic expression of these genes may differ between lean-NGT and obese-diabetic groups of P. obesus. Subsequent studies will explore the potential role of these novel and known genes in the pathophysiology of type 2 diabetes.

Novel gene discovery in the muscle of obese-diabetic Psammomys obesus

Metabolism in Psammomys obesis, a polygenic animal model of obesity and type 2 diabetes is associated with dysregulated nocturnal fat oxidation in diabetic animals. Furthermore, a new gene called AGT-203 has been identified. Evidence indicates that AGT-203 is involved in abnormal glucose metabolism leading to the proposition that AGT-203 is a new candidate gene for type 2 diabetes.

Azimuth

The exhibition,"Azimuth", looks at earth and space in a series of visually spectaculor works by the two artists. Daniel Armstrong’s series of digital photographs are heavily manipulated grids of astronomical images sampled from the night sky with time exposures of a number of seconds using both analog and digital recording equipment. These grids are reconfigurations of those stars that impose such presence on one’s visual nocturnal experience of regional Victoria. James McArdle's photographs deal with the human sensations of being on the ground, in the landscape.