229 research outputs found
The value of animal behaviour as a bio-indicator of restoration quality
Woodland restoration is a complex endeavour, and restoration ecology as a scientific discipline requires constant re-assessments and adjustments if it is to improve outcomes and better provide for biodiversity. The promise of effective restoration is often used to justify destructive processes that affect many of the world’s ecosystems. It is therefore imperative that those promises can be met, which comes down to restoration ecologists’ and land managers’ capacity to predict and facilitate desirable ecological changes in a timely and socio-economically responsible manner. As perspectives have changed, and knowledge has been gained over the past few decades there have been several fundamental shifts in how restoration is done. Efforts to ‘beautify’ degraded areas through the planting of fast growing non-native species is no longer thought of as responsible restoration practice. We have a better understanding of ecological thresholds, the creation of novel ecosystems and the ways ecosystems move between stable states through transitional processes. Yet many restoration projects still fail to deliver positive outcomes for certain taxonomic groups. Fauna are an important component of biodiversity, and yet ecological filters and traps remain common in restored habitats.
To date, the focus in restoration has been biased towards restoring flora, while fauna have been under-appreciated and under-utilised. This is likely due to a lack of clarity around how fauna can be used to assess restoration success. This study sought to address that issue by exploring ways fauna could be used to assess habitat quality, and evaluate whether they could fit into existing restoration management tools like a state-and-transition model. Variation in habitat quality was assessed using a number of biodiversity measures and behavioural patterns. This study used Rottnest Island in Western Australia, a mosaic landscape with a woodland restoration program that has been running for over 50 years. The Island’s woodland areas support a resident population of red-capped robins Petroica goodenovii, which was the focal species of this study. The robins are typically groundforaging insectivores that generally have been found to respond negatively to anthropocentric land use changes.
The suitability of the Island’s robin population as an indicator for the larger avian community was assessed to determine whether management and monitoring could simply focus on improving conditions for robins. Unfortunately, robins were found to be a poor indicator of the larger avian community. Factors that were positively correlated with estimated robin density, like woodland area and time since last fire, were negatively correlated with density of other avian species of conservation significance.
Invertebrate assembly was surveyed as a measure of food resource availability. There was a significant difference between woodland and heathland areas and to a lesser, but still significant, extent between restored woodland areas of different ages and remnant woodland. A major finding of this study was that Coleoptera were scarcely encountered in ground samples outside of remnant patches, but were among the most common orders in arboreal samples, specifically in old restoration. Given that this order is a major component of numerous insectivore diets, it is likely that this difference is influencing foraging habitat quality. This conclusion is supported by difference detected in the birds’ foraging behaviour, as birds in remnants foraged predominantly on the ground, while in restored areas birds were frequently observed collecting prey items from vegetation.
Aside from changing their foraging behaviour, the birds were also found to rarely display breeding related behaviours while in restored habitat. This mimicked a significant difference in juvenile robin population density between restored and remnant patches during the breeding season. As such, it appears robins readily use restored areas for feeding resources, but remnants remain a crucial component of their functional habitat requirements, providing important breeding habitat.
Behaviour was found to be a useful tool in explaining and verifying measured differences in habitat quality, and in this case, could easily be incorporated into pre-existing fauna monitoring programs. Robins weren’t found to be a suitable indicator species for the bird community, and given the small species pool on the island, management may need to consider all species of conservation significance separately
Serrated trailing edges for improving lift and drag characteristics of lifting surfaces
An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface
Physiological Constants of the Entomopathogenic Bacterium Xenorhabdus Nematophila Determined by Microbial Growth Kinetics
Xenorhabdus nematophila, an entomopathogenic bacterium that symbiotically associates with the entomoparasitic nematode Steinernema carpocapsae, was studied to determine its physiological parameters of glucose utilization. X. nematophila was cultured in chemically defined media containing various concentrations of glucose under optimal conditions utilizing a two-liter fermentation system. Specific growth rates were obtained from each glucose batch. Specific growth rates and their associated glucose concentrations were used to determine physiological parameters. These parameters include the bacterium's substrate utilization constant (K s ) and its maximum specific growth rate (µ max). The bacteria exhibited a K s value of 2.02 mg/L suggesting that X. nematophila has a high affinity for glucose. The µ max of Xenorhabdus was determined to be 1.03 h(-1). Further research is needed to determine if microbial affinities to different substrates have any influence on biological relationships (symbiosis, pathogenicity, parasitism, etc.) between prokaryotes and higher organisms
'Getting people on board': Discursive leadership for consensus building in team meetings
Meetings are increasingly seen as sites where organizing and strategic change take place, but the role of specific discursive strategies and related linguistic-pragmatic and argumentative devices, employed by meeting chairs, is little understood. The purpose of this article is to address the range of behaviours of chairs in business organizations by comparing strategies employed by the same chief executive officer (CEO) in two key meeting genres: regular management team meetings and ‘away-days’. While drawing on research from organization studies on the role of leadership in meetings and studies of language in the workplace from (socio)linguistics and discourse studies, we abductively identified five salient discursive strategies which meeting chairs employ in driving decision making: (1) Bonding; (2) Encouraging; (3) Directing; (4) Modulating; and (5) Re/Committing. We investigate the leadership styles of the CEO in both meeting genres via a multi-level approach using empirical data drawn from meetings of a single management team in a multinational defence corporation. Our key findings are, first, that the chair of the meetings (and leading manager) influences the outcome of the meetings in both negative and positive ways, through the choice of discursive strategies. Second, it becomes apparent that the specific context and related meeting genre mediate participation and the ability of the chair to control interactions within the team. Third, a more hierarchical authoritarian or a more interpersonal egalitarian leadership style can be identified via specific combinations of these five discursive strategies. The article concludes that the egalitarian leadership style increases the likelihood of achieving a durable consensus. Several related avenues for research are outlined
The challenges of developing a contrast-based video game for treatment of amblyopia
Perceptual learning of visual tasks is emerging as a promising treatment for amblyopia, a developmental disorder of vision characterized by poor monocular visual acuity. The tasks tested thus far span the gamut from basic psychophysical discriminations to visually complex video games. One end of the spectrum offers precise control over stimulus parameters, whilst the other delivers the benefits of motivation and reward that sustain practice over long periods. Here, we combined the advantages of both approaches by developing a video game that trains contrast sensitivity, which in psychophysical experiments, is associated with significant improvements in visual acuity in amblyopia. Target contrast was varied adaptively in the game to derive a contrast threshold for each session. We tested the game on 20 amblyopic subjects (10 children and 10 adults), who played at home using their amblyopic eye for an average of 37 sessions (approximately 11 h). Contrast thresholds from the game improved reliably for adults but not for children. However, logMAR acuity improved for both groups (mean = 1.3 lines; range = 0–3.6 lines). We present the rationale leading to the development of the game and describe the challenges of incorporating psychophysical methods into game-like settings
Antihypertensive Drug Guanabenz Is Active In Vivo against both Yeast and Mammalian Prions
Background: Prion-based diseases are incurable transmissible neurodegenerative disorders affecting animals and humans. [br/] Methodology/Principal Findings: Here we report the discovery of the in vivo antiprion activity of Guanabenz (GA), an agonist of a2-adrenergic receptors routinely used in human medicine as an antihypertensive drug. We isolated GA in a screen for drugs active in vivo against two different yeast prions using a previously described yeast-based two steps assay. GA was then shown to promote ovine PrPSc clearance in a cell-based assay. These effects are very specific as evidenced by the lack of activity of some GA analogues that we generated. GA antiprion activity does not involve its agonist activity on a2-adrenergic receptors as other chemically close anti-hypertensive agents possessing related mechanism of action were found inactive against prions. Finally, GA showed activity in a transgenic mouse-based in vivo assay for ovine prion propagation, prolonging slightly but significantly the survival of treated animals. [br/] Conclusion/Significance: GA thus adds to the short list of compounds active in vivo in animal models for the treatment of prion-based diseases. Because it has been administrated for many years to treat hypertension on a daily basis, without major side-effects, our results suggest that it could be evaluated in human as a potential treatment for prion-based diseases
Crustal thickness variations along the Southeast Indian Ridge (100°–116°E) from 2-D body wave tomography
Axial morphology along the Southeast Indian Ridge (SEIR) systematically changes from an axial high to a deep rift valley at a nearly uniform intermediate spreading rate between 100°–116°E, west of the Australian-Antarctic Discordance (AAD). Basalt geochemistry has a consistent Indian–mid-ocean ridge basalt (MORB) type isotopic signature, so changes in axial topography are attributed to variations in both mantle temperature and melt supply. Wide-angle seismic refraction lines were shot to four ocean bottom hydrophones within SEIR segments P1, P2, S1, and T, where each segment is characterized by a different morphology. We constructed 2-D crustal velocity models by jointly inverting hand-picked P wave refraction (Pg) and Moho reflection (PmP) traveltime data using a top-down, minimum-structure methodology. The results show a 1.5 km eastward decrease in crustal thickness across the study area, with segment averages ranging from 6.1 km at P1 to 4.6 km at T. Melt generation models require a ~30°C decrease in mantle temperature toward the AAD to account for the crustal thickness trend. Significant changes in axial morphology accompany small-scale variations in crustal thickness, consistent with models of crustal accretion where ridge topography is determined by a balance between mantle temperature, melt supply, and cooling from hydrothermal circulation. Layer 3 thins by 3.0 km as layer 2 thickens by 1.4 km between segments P1 and T, reflecting the eastward decrease in melt supply and increase in melt lens depth. The trade-off in seismic layers may be explained by models relating the increase in overburden pressure on a deepening melt lens to the volume of magma erupted into the upper crust rather than cooling at depth to form new lower crustal material
Exploration of Shared Genetic Architecture Between Subcortical Brain Volumes and Anorexia Nervosa
In MRI scans of patients with anorexia nervosa (AN), reductions in brain volume are often apparent. However, it is unknown whether such brain abnormalities are influenced by genetic determinants that partially overlap with those underlying AN. Here, we used a battery of methods (LD score regression, genetic risk scores, sign test, SNP effect concordance analysis, and Mendelian randomization) to investigate the genetic covariation between subcortical brain volumes and risk for AN based on summary measures retrieved from genome-wide association studies of regional brain volumes (ENIGMA consortium, n = 13,170) and genetic risk for AN (PGC-ED consortium, n = 14,477). Genetic correlations ranged from − 0.10 to 0.23 (all p > 0.05). There were some signs of an inverse concordance between greater thalamus volume and risk for AN (permuted p = 0.009, 95% CI: [0.005, 0.017]). A genetic variant in the vicinity of ZW10, a gene involved in cell division, and neurotransmitter and immune system relevant genes, in particular DRD2, was significantly associated with AN only after conditioning on its association with caudate volume (pFDR = 0.025). Another genetic variant linked to LRRC4C, important in axonal and synaptic development, reached significance after conditioning on hippocampal volume (pFDR = 0.021). In this comprehensive set of analyses and based on the largest available sample sizes to date, there was weak evidence for associations between risk for AN and risk for abnormal subcortical brain volumes at a global level (that is, common variant genetic architecture), but suggestive evidence for effects of single genetic markers. Highly powered multimodal brain- and disorder-related genome-wide studies are needed to further dissect the shared genetic influences on brain structure and risk for AN
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