Australia’s savanna herbivores : bioclimatic distributions and an assessment of the potential impact of regional climate change

The future impacts of climate change are predicted to significantly affect the survival of many species. Recent studies indicate that even species that are relatively mobile and/or have large geographic ranges may be at risk of range contractions or extinction. An ecologically and evolutionary significant group of mammals that has been largely overlooked in this research is Australia’s large marsupial herbivores, the macropodids (kangaroos). The aims of our investigation were to define and compare the climatic conditions that influence the current distributions of four sympatric large macropodids in northern Australia (Macropus antilopinus, Macropus robustus, Macropus giganteus, and Macropus rufus) and to predict the potential future impact of climate change on these species. Our results suggest that contemporary distributions of these large macropodids are associated with well‐defined climatic gradients (tropical and temperate conditions) and that climatic seasonality is also important. Bioclimatic modeling predicted an average reduction in northern Australian macropodid distributions of in response to increases of 2.0°C. At this temperature, the distribution of M. antilopinus was reduced by . We predict that increases of 6.0°C may cause severe range reductions for all four macropodids ( ) in northern Australia, and this range reduction may result in the extinction of M. antilopinus.

Measurement of aqueous film thickness between charged mercury and mica surfaces : a direct experimental probe of the Poisson-Boltzmann distribution

A stable aqueous electrolyte film is formed between a mercury drop and a flat mica surface due to electrical double-layer repulsion when a negative potential is applied to the mercury. Film thickness has been measured as a function of applied potential while keeping the film pressure constant. By making measurements in this way, it is possible to map the data directly according to the Poisson-Boltzmann equation. An excellent fit to the data is obtained, providing direct evidence for this classical equation and its use as the basis of the Gouy-Chapman model of the diffuse double layer in electrolyte solutions.

Edge effects in patchy seagrass landscapes : the role of predation in determining fish distribution

Predation is often described as an underlying mechanism to explain edge effects. We assessed the importance of predation in determining edge effects in seagrass using two approaches: a video survey to sample predators at small scales across seagrass edges, and a tethering experiment to determine if predation was an underlying mechanism causing edge effects. Underwater videos were placed at four positions: middle of seagrass patches; edge of seagrass; sand immediately adjacent to seagrass and sand distant from seagrass. Fish abundances and the time fish spent in view were measured. The main predatory fish (Australian salmon, Arripis spp.) spent more time over adjacent sand than other positions, while potential prey species (King George whiting, Sillaginodes punctata (Cuvier), recruits) were more common in the middle of seagrass patches. Other species, including the smooth toadfish, Tetractenos glaber (Freminville), and King George whiting adults, spent more time over sand adjacent to seagrass than distant sand, which may be related to feeding opportunities. King George whiting recruits and pipefish (Stigmatopora spp.) were tethered at each of the four positions. More whiting recruits were preyed upon at outer than inner seagrass patches, and survival time was greater in the middle of shallow seagrass patches than other positions. Relatively few pipefish were preyed upon, but of those that were, survival time was lower over sand adjacent to seagrass than at the seagrass edge or middle. Video footage revealed that salmon were the dominant predators of both tethered King George whiting recruits and pipefish. The distribution of predators and associated rate of predation can explain edge effects for some species (King George whiting) but other mechanisms, or combinations of mechanisms, are determining edge effects for other species (pipefish).

Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of amaryllidaceae

Background During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive approach enabling more efficient selection of plants for the development of traditional medicine and lead discovery. However, this relationship has rarely been rigorously tested and the potential predictive power is consequently unknown.
Results We produced a phylogenetic hypothesis for the medicinally important plant subfamily Amaryllidoideae (Amaryllidaceae) based on parsimony and Bayesian analysis of nuclear, plastid, and mitochondrial DNA sequences of over 100 species. We tested if alkaloid diversity and activity in bioassays related to the central nervous system are significantly correlated with phylogeny and found evidence for a significant phylogenetic signal in these traits, although the effect is not strong.
Conclusions Several genera are non-monophyletic emphasizing the importance of using phylogeny for interpretation of character distribution. Alkaloid diversity and in vitro inhibition of acetylcholinesterase (AChE) and binding to the serotonin reuptake transporter (SERT) are significantly correlated with phylogeny. This has implications for the use of phylogenies to interpret chemical evolution and biosynthetic pathways, to select candidate taxa for lead discovery, and to make recommendations for policies regarding traditional use and conservation priorities.

Polystyrene-b-poly(oligo(ethylene oxide) monomethyl ether methacrylate)-bpolystyrene triblock copolymers as potential carriers for hydrophobic drugs

A simple and effective method is introduced to synthesize a series of polystyrene-b-poly(oligo(ethylene oxide) monomethyl ether methacrylate)-b- polystyrene (PSt-b-POEOMA-b-PSt) triblock copolymers. The structures of PSt-b-POEOMA-b-PSt copolymers were characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopy. The molecular weight and molecular weight distribution of the copolymer were measured by gel permeation chromatography (GPC). Furthermore£ the self-assembling and drug-loaded behaviours of three different ratios of PSt-b-POEOMA-b-PSt were studied. These copolymers could readily self-assemble into micelles in aqueous solution. The vitamin E-loaded copolymer micelles were produced by the dialysis method. The micelle size and core-shell structure of the block copolymer micelles and the drug-loaded micelles were confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The thermal properties of the copolymer micelles before and after drug-loaded were investigated by different scanning calorimetry (DSC). The results show that the micelle size is slightly increased with increasing the content of hydrophobic segments and the micelles are still core-shell spherical structures after drug-loaded. Moreover, the glass transition temperature (Tg) of polystyrene is reduced after the drug loaded. The drug loading content (DLC) of the copolymer micelles is 70%-80% by ultraviolet (UV) photolithography analysis. These properties indicate the micelles self-assembled from PSt-b- POEOMA-b- PSt copolymers would have potential as carriers for the encapsulation of hydrophobic drugs.

Distribution, extent of inter-annual variability and diet of the bloom-forming jellyfish Rhizostoma in European waters

Jellyfish (Cnidaria: Scyphozoa) are increasingly thought to play a number of important ecosystem roles, but often fundamental knowledge of their distribution, seasonality and inter-annual variability is lacking. Bloom forming species, due to their high densities, can have particularly intense trophic and socio-economic impacts. In northern Europe it is known that one particularly large (up to 30 kg wet weight) bloom forming jellyfish is Rhizostoma spp. Given the potential importance, we set out to review all known records from peer-reviewed and broader public literature of the jellyfish R. octopus (Linnaeus) and R. pulmo (Macri) (Scyphozoa: Rhizostomae) across western Europe. These data revealed distinct hotspots where regular Rhizostoma spp. aggregations appeared to form, with other sites characterized by occasional abundances and a widespread distribution of infrequent observations. Surveys of known R. octopus hotspots around the Irish Sea also revealed marked inter-annual variation with particularly high abundances forming during 2003. The location of such consistent aggregations and inter-annual variances are discussed in relation to physical, climatic and dietary variations.

The ocean sunfish Mola mola : insights into distribution, abundance and behaviour in the Irish and Celtic Seas

Here we provide baseline data on the distribution and abundance of Mola mola within the Irish and Celtic Seas, made during aerial surveys from June to October during 2003–2005. These data were considered in conjunction with concurrent observations of three potential jellyfish prey species found throughout the region: Rhizostoma octopus, Chrysaora hysoscella and Cyanea capillata. A total area of 7850 km2 was surveyed over the three years with an observed abundance of 68 sunfish giving a density of 0.98 ind/100 km2. Although modest, these findings highlight that the species is more common than once thought around Britain and Ireland and an order of magnitude greater than the other apex jellyfish predator found in the region, the leatherback turtle (Dermochelys coriacea). Furthermore, the distribution of sunfish sightings was inconsistent with the extensive aggregations of Rhizostoma octopus found throughout the study area. The modelled distributions of predator–prey co-occurrence (using data for all three jellyfish species) was less than the observed co-occurrence with the implication that neither jellyfish nor sunfish were randomly distributed but co-occurred more in the same areas than expected by chance. Finally, observed sunfish were typically small ([similar]1 m or less) and seen to either bask or actively swim at the surface.

Voltage regulation in renewable energy integration into the distribution network

Large-scale renewable energy (RE) integration into the distribution network (DN) causes uncertainties due to its intermittent nature and is a challenging task today. In general RE sources are mostly connected near the end user level, i.e., in the low voltage distribution network. RE integration introduces bi-directional power flows across distribution transformer (DT) and hence DN experiences with several potential problems that includes voltage fluctuations, reactive power compensation and poor power factor in the DN. This study identifies the potential effects causes due to large-scale integration of RE into the Berserker Street Feeder, Frenchville Substation under Rockhampton DN. From the model analyses, it has clearly evident that voltage of the Berserker Street Feeder fluctuates with the increased integration of RE and causes uncertainties in the feeder as well as the DN.

Influences of wind energy integration into the distribution network

Wind energy is one of the most promising renewable energy sources due to its availability and climate-friendly attributes. Large-scale integration of wind energy sources creates potential technical challenges due to the intermittent nature that needs to be investigated and mitigated as part of developing a sustainable power system for the future. Therefore, this study developed simulation models to investigate the potential challenges, in particular voltage fluctuations, zone substation, and distribution transformer loading, power flow characteristics, and harmonic emissions with the integration of wind energy into both the high voltage (HV) and low voltage (LV) distribution network (DN). From model analysis, it has been clearly indicated that influences of these problems increase with the increased integration of wind energy into both the high voltage and low voltage distribution network, however, the level of adverse impacts is higher in the LV DN compared to the HV DN.

Living on the edge: how philopatry maintains adaptive potential.

Without genetic variation, species cannot cope with changing environments, and evolution does not proceed. In endangered species, adaptive potential may be eroded by decreased population sizes and processes that further reduce gene flow such as philopatry and local adaptations. Here, we focused on the philopatric and endangered loggerhead sea turtle (Caretta caretta) nesting in Cape Verde as a model system to investigate the link between adaptive potential and philopatry. We produced a dataset of three complementary genomic regions to investigate female philopatric behaviour (mitochondrial DNA), male-mediated gene flow (microsatellites) and adaptive potential (major histocompatibility complex, MHC). Results revealed genetically distinct nesting colonies, indicating remarkably small-scale philopatric behaviour of females. Furthermore, these colonies also harboured local pools of MHC alleles, especially at the margins of the population's distribution, which are therefore important reserves of additional diversity for the population. Meanwhile, directional male-mediated gene flow from the margins of distribution sustains the adaptive potential for the entire rookery. We therefore present the first evidence for a positive association between philopatry and locally adapted genomic regions. Contrary to expectation, we propose that philopatry conserves a high adaptive potential at the margins of a distribution, while asymmetric gene flow maintains genetic connectivity with the rest of the population.

Impact of SCIG and DFIG type wind turbine on the stability of distribution networks: Static and dynamic aspects

This paper presents potential barriers to integrate the squirrel cage induction generator (SCIG) and doubly fed induction generator (DFIG) type wind turbine in distribution networks. The analysis is carried out over a 16 bus distribution test system. Both static and dynamic analyses are performed to see the impact of two different generators on the distribution system. The simulation results show that both SCIG and DFIG type wind turbines have significant impact on the static voltage stability, power loss, and dynamic behavior of the system, which should be taken into account to improve systems performance before integrating wind generation in existing distribution networks.

D-STATCOM control in distribution networks with composite loads to ensure grid code compatible performance of photovoltaic generators

This paper proposes an optimal linear quadratic Gaussian (LQG) controller for D-STATCOM to improve the dynamic performance of distribution networks with photovoltaic generators. The controller is designed based on the H∞ norm of the uncertain system. The change in system model due to the variation of load compositions in the composite load is considered as an uncertain term in the design algorithm. The performance of the designed controller is demonstrated on a widely used test system. Simulation results indicate that the proposed controller can be a potential solution for improving the voltage stability of distribution networks.

Does urbanization have the potential to create an ecological trap for powerful owls (Ninox strenua)?

Landscape transformation associated with urbanization is one of the most damaging and pervasive impacts humans have on natural ecosystems. The response of species to increasing urbanization has become a major focus of research globally. Powerful owls ( Ninox strenua) are a top-order predator the have been shown to reside in urban environments, but increasing urbanization has also been demonstrated to significantly reduce available habitat. In this paper we use species distribution models established for key food and nesting resources of powerful owls across an urban-forest gradient to constrain habitat predictions from a previously developed powerful owl species distribution model. This multi-criteria decision analysis (MCDA) approach allowed us to investigate the impacts of urbanization on potential powerful owl habitat when challenged with food and nesting requirements. As powerful owls only use tree cavities for nesting we propose that the cue for settlement in an area is associated with the presence of habitat and food and as such breeding requirements may be disconnected from settlement requirements.Our results demonstrate that incorporation of a general prey resource (at least one group of arboreal marsupials) as a cue for settlement does not reduce the amount of available habitat for powerful owls substantially. Further constraining the model with a tree cavity resource, however, leads to a substantial reduction in powerful owl habitat in the urban and urban fringe environments. If a diverse prey resource (two or more groups of arboreal marsupials) is used as the cue for settlement, this sees a substantial reduction in available habitat in urban environments. Incorporation of tree cavities into this model does not reduce the available habitat for powerful owls substantially.We propose that powerful owls do not need a diverse prey base for survival, and that breeding resources are unlikely to be a cue for settlement. As such, we argue in this paper that increasing urbanization has the potential to create an ecological trap for powerful owls as there is a significant difference between habitat capable of supporting powerful owls, and habitat in which owls can breed.Management of powerful owls in urban environments will be difficult, but this research highlights the potential for the use of nest boxes to enhance the breeding activities in increasingly urbanized environments. Replacement of this critical resource may be able to reverse any potential ecological trap that is occurring. © 2014 Elsevier Ltd.

Senior marketers’ insights into the challenges of social media implementation in large organisations: assessing generic and electronic orientation models as potential solutions

The unique characteristics of social media (SM) have made it difficult to implement this tool within many large organisations. This paper seeks to identify the implementation challenges and evaluate alternative organisational orientations that may provide solutions. We aimed to reconcile theory with current practice by integrating the extant literature with data from three focus groups involving 27 senior marketing executives. The managerial discussions identified additional challenges to those previously discussed in the literature, which appear to result from SM’s unique characteristics. These include: interactivity, the integration of communication into distribution channels, collaborative media and information collection. Using both broad orientation models (market orientation and entrepreneurial orientation) and a specific digital orientation (e-marketing orientation), guidelines and research propositions for effective implementation are put forward.

Integration of roof-top solar photovoltaic systems into the low voltage distribution network

The advancement in solar photovoltaic (PV) technology, the cost and efficiency of PVs have encouraged users worldwide to adopt more and more PVs as it is free from greenhouse gas emissions and unlimited in nature. Integration of roof-top solar PV systems is currently emerging rapidly in Australia as the governments are giving attractive incentives and encouraging households to build a sustainable climate-friendly society for the future. The key major barriers to the integration of roof-top solar PV systems are the uncertainties in the performance of the low voltage distribution network due to the intermittent nature of solar PV sources. In this paper, a model was developed to investigate the potential technical impacts of integrating roof-top solar PV systems into the low voltage distribution network in a subtropical climate. The results show that integration of roof-top solar PV in the customer premises causes uncertainties such as voltage fluctuations, phase unbalance, distribution transformer overloading, reactive power compensation, and harmonic injections that detract the overall power quality of the typical distribution network. © 2014 AIP Publishing LLC.