Sheep, dingoes and kangaroos: new challenges and a change of direction 20 years on

Predation and competition are two primary forces limiting the extent to which sheep can be grazed in the Australian rangelands, particularly in Queensland. Dingo predation has been non-existent in much of the sheep zone since the localised eradication of dingoes in the early 1900s. Competition with kangaroos has been ever-present, but was previously managed (to some extent) by the commercial kangaroo harvesting industry. However, changes to dingo distribution and kangaroo densities and harvesting over the last 20 years have meant that dingo predation and kangaroo competition again threaten viable sheep production in the rangelands. Dingoes have increased their distribution and density in almost all sheep grazing areas and contemporary lethal control efforts are not preventing the decline of sheep. Loss of valuable international markets and moves to now harvest only adult male kangaroos means that the kangaroo harvesting industry produces little relief from kangaroo grazing pressure (given that kangaroo population growth is little affected by removal of adult males; see Finch et al. this volume). New approaches to dingo and kangaroo management are sorely needed to salvage and restore the production of sheep in the rangelands. In response, the installation and use of pest-proof fences is rapidly increasing in Queensland and other areas, facilitating, for the first time in nearly a century, the localised eradication of dingoes and the suppression of kangaroos to manageable numbers within fenced areas. We describe these challenges and opportunities for one site in particular (Leander Station), and offer a sheep grazier’s perspective on past and future use and management of problematic wildlife in sheep production zones

More buck for less bang: Reconciling competing wildlife management interests in agricultural food webs

Mammalian top-predators can have positive, negative and negligible effects on economic, environmental and social values, which vary spatially and temporally. Harnessing 'pros' while mitigating 'cons' of top-predators remains a key management challenge, particularly outside reserves in agro-ecosystems. In this study, long-term (1972-2008) and broad-scale (250,000km) datasets were used to explore co-relationships between rainfall, kangaroo abundance, beef-cattle calf production and dingo control effort in arid Australia. Best subsets and multiple regression analyses show that calf production fluctuates independently of dingo control, and kangaroo populations comprise 13-36% (mean 26%) of the combined kangaroo-cattle herd in any given year. Kangaroo abundance was associated most strongly with bottom-up forces (rainfall) as expected, but a combination of bottom-up (rainfall) and top-down (dingo control) processes best explained variation in kangaroo abundance trends. Supplementary economic analysis indicated that ongoing kangaroo competition with cattle is far more costly to beef producers than the occasional predation of calves by dingoes. These results suggest that lethal top-predator control practices in arid Australia may not be achieving their fundamental aim (to increase livestock production) because increased competition from native herbivores freed from top-predator suppression erodes the accrued economic benefits of a reduction in livestock predation. These data suggest that retaining top-predators outside reserves in agro-ecosystems may be advantageous to livestock producers and ecosystems where and/or when top-predators exert stronger effects on livestock competitors than they do on livestock. These data also highlight how increased knowledge of species interactions can reconcile competing wildlife management interests in agricultural food webs

Continuous Gravitational Waves from Isolated Galactic Neutron Stars in the Advanced Detector Era

We consider a simulated population of isolated Galactic neutron stars. The rotational frequency of each neutron star evolves through a combination of electromagnetic and gravitational wave emission. The magnetic field strength dictates the dipolar emission, and the ellipticity (a measure of a neutron star's deformation) dictates the gravitational wave emission. Through both analytic and numerical means, we assess the detectability of the Galactic neutron star population and bound the magnetic field strength and ellipticity parameter space of Galactic neutron stars with or without a direct gravitational wave detection. While our simulated population is primitive, this work establishes a framework by which future efforts can be conducted.Comment: Accepted for publication by Physical Review D, 8 pages, 5 figure

Wild dogma: An examination of recent "evidence" for dingo regulation of invasive mesopredator release in Australia

There is growing interest in the role that apex predators play in shaping terrestrial ecosystems and maintaining trophic cascades. In line with the mesopredator release hypothesis, Australian dingoes (Canis lupus dingo and hybrids) are assumed by many to regulate the abundance of invasive mesopredators, such as red foxes Vulpes vulpes and feral cats Felis catus, thereby providing indirect benefits to various threatened vertebrates. Several recent papers have claimed to provide evidence for the biodiversity benefits of dingoes in this way. Nevertheless, in this paper we highlight several critical weaknesses in the methodological approaches used in many of these reports, including lack of consideration for seasonal and habitat differences in activity, the complication of simple track-based indices by incorporating difficult-to-meet assumptions, and a reduction in sensitivity for assessing populations by using binary measures rather than potentially continuous measures. Of the 20 studies reviewed, 15 of them (75%) contained serious methodological flaws, which may partly explain the inconclusive nature of the literature investigating interactions between invasive Australian predators. We therefore assert that most of the "growing body of evidence" for mesopredator release is merely an inconclusive growing body of literature only. We encourage those interested in studying the ecological roles of dingoes relative to invasive mesopredators and native prey species to account for the factors we identify, and caution the value of studies that have not done so

Cascading Activation Revisited: How Audiences Contribute to News Agendas Using Social Media

Social media have become conduits through which audiences can challenge elites in media and politics. Recent updates to cascading activation, originally developed to explain how frames flowing from powerful figures gain public dominance, give greater theoretical scope for audiences to exert influence. Yet empirical understanding of how and in what circumstances this happens with respect to agenda-setting - another core media effect - is not well-developed, especially given the affordances of digital technologies. We address this gap by connecting theorization on cascades to developments in intermedia agenda-setting. Specifically, we analyze the dynamics surrounding the perceived reluctance by ARD-aktuell, the newsroom of Germany's public broadcasting consortium, to use its prime-time broadcast "Tagesschau" to report the arrest of a refugee accused of murdering a German woman in December 2016. By presenting finely grained timelines linking content analysis of 5,409 Facebook comments with Tagesschau editorial responses and parallel media coverage of this event, we contribute further conditions under which audience-informed cascades may occur: notably, when publicly funded news organizations are involved, and the issue at stake invokes both domestic and international aspects which sustain disagreement

Terrestrial mesopredators did not increase after top-predator removal in a large-scale experimental test of mesopredator release theory

Removal or loss of top-predators has been predicted to cause cascading negative effects for ecosystems, including mesopredator release. However, reliable evidence for these processes in terrestrial systems has been mixed and equivocal due, in large part, to the systemic and continued use of low-inference study designs to investigate this issue. Even previous large-scale manipulative experiments of strong inferential value have been limited by experimental design features (i.e. failure to prevent migration between treatments) that constrain possible inferences about the presence or absence of mesopredator release effects. Here, we build on these previous strong-inference experiments and report the outcomes of additional large-scale manipulative experiments to eradicate Australian dingoes from two fenced areas where dingo migration was restricted and where theory would predict an increase in extant European red foxes, feral cats and goannas. We demonstrate the removal and suppression of dingoes to undetectable levels over 4–5 years with no corresponding increases in mesopredator relative abundances, which remained low and stable throughout the experiment at both sites. We further demonstrate widespread absence of negative relationships between predators, indicating that the mechanism underpinning predicted mesopredator releases was not present. Our results are consistent with all previous large-scale manipulative experiments and long-term mensurative studies which collectively demonstrate that (1) dingoes do not suppress red foxes, feral cats or goannas at the population level, (2) repeated, temporary suppression of dingoes in open systems does not create mesopredator release effects, and (3) removal and sustained suppression of dingoes to undetectable levels in closed systems does not create mesopredator release effects either. Our experiments add to similar reports from North America, Asia, Europe and southern Africa which indicate that not only is there a widespread absence of reliable evidence for these processes, but there is also a large and continually growing body of experimental evidence of absence for these processes in many terrestrial systems. We conclude that although sympatric predators may interact negatively with each other on smaller spatiotemporal scales, that these negative interactions do not always scale-up to the population level, nor are they always strong enough to create mesopredator suppression or release effects

The Temporal Relationship between Stress and Spasticity, a Comparison between Subjects with and without Intact Thyroid Function

Purpose/Hypothesis: Stress has been studied as a credible trigger of spasticity, but evidence is limited concerning temporal relationships. Case studies of complex regional pain syndrome (CRPS) and fibromyalgia (FM) have established a ten-day delay between psychogenic stress and episodic pain flares. This is explained by a stress induced release of thyroxine (T4) from the thyroid gland via the hypothalamus-pituitary-thyroid (HPT) axis, which reaches its peak effect by day 10. Models suggest that T4 may increase peripheral nerve excitability, which could increase sensitivity in 1A fibers from muscle spindles, leading to hyper-excitability in motor neuron pools. The purpose of our study is to explore the temporal relationship between stress & spasticity, to see if subjects experience latent increases in spasticity due to stress. Subjects: Subjects ranged from 48-84 years old, including one male with CVA history & one female with CVA history s/p thyroidectomy. Materials/Methods: Every day for 12 weeks, participants completed stress and spasticity inventories. Stress was measured with a visual analog stress scale (VASS) and spasticity with a visual analog functional scale (VAFS) assessing the degree of difficulty to execute a standard daily task due to spasticity severity. Quantitative criteria were established defining days of peak stress and days of peak spasticity. Final temporal relationship results between stress and spasticity were analyzed with serial lag correlations for 0-12 day lags. Results: After 12 weeks of data collection, the male manifested a significant correlation to spasticity related function ten days after criterion peak stress days. Serial lag analysis on peak stress days for this person revealed a 70% correlation supporting a 10-day impact on peak spasticity. The female subject revealed one event in spasticity-related function 10 days after peak stress event, which yields an insignificant 10-day lag correlation of 9.1%. This subject, with history of thyroidectomy, reports taking daily administration of levothyroxine. Consequently, her results are not surprising, since her HTP pathway cannot be influenced by stress. Conclusions: Based on results, evidence supports an increase in CVA-related spasticity ten days after high stress episodes. This relationship was not observed in our female subject s/p thyroidectomy, lending inverse support to the hypothesis that latent ten-day effects may be due to the HPT axis. Clinical Relevance: Patients and therapists frequently are at a loss to explain episodic elevations in spasticity severity. If a consistent temporal relationship between stress and spasticity is confirmed, it would give caregivers, patients, and therapists insight into understanding and predicting episodes of decreased function following high stress days

A Persistent Simulation Environment for Autonomous Systems

The age of Autonomous Unmanned Aircraft Systems (AUAS) is creating new challenges for the accreditation and certification requiring new standards, policies and procedures that sanction whether a UAS is safe to fly. Establishing a basis for certification of autonomous systems via research into trust and trustworthiness is the focus of Autonomy Teaming and TRAjectories for Complex Trusted Operational Reliability (ATTRACTOR), a new NASA Convergent Aeronautics Solution (CAS) project. Simulation Environments to test and evaluate AUAS decision making may be a low-cost solution to help certify that various AUAS systems are trustworthy enough to be allowed to fly in current general and commercial aviation airspace. NASA is working to build a peer-to-peer persistent simulation (P3 Sim) environment. The P3 Sim will be a Massively Multiplayer Online (MMO) environment were AUAS avatars can interact with a complex dynamic environment and each other. The focus of the effort is to provide AUAS researchers a low-cost intuitive testing environment that will aid training for and assessment of decisions made by autonomous systems such as AUAS. This presentation focuses on the design approach and challenges faced in development of the P3 Sim Environment is support of investigating trustworthiness of autonomous systems

Role of heparan sulfate as a tissue-specific regulator of FGF-4 and FGF receptor recognition

FGF signaling uses receptor tyrosine kinases that form high-affinity complexes with FGFs and heparan sulfate (HS) proteoglycans at the cell surface. It is hypothesized that assembly of these complexes requires simultaneous recognition of distinct sulfation patterns within the HS chain by FGF and the FGF receptor (FR), suggesting that tissue-specific HS synthesis may regulate FGF signaling. To address this, FGF-2 and FGF-4, and extracellular domain constructs of FR1-IIIc (FR1c) and FR2-IIIc (FR2c), were used to probe for tissue-specific HS in embryonic day 18 mouse embryos. Whereas FGF-2 binds HS ubiquitously, FGF-4 exhibits a restricted pattern, failing to bind HS in the heart and blood vessels and failing to activate signaling in mouse aortic endothelial cells. This suggests that FGF-4 seeks a specific HS sulfation pattern, distinct from that of FGF-2, which is not expressed in most vascular tissues. Additionally, whereas FR2c binds all FGF-4–HS complexes, FR1c fails to bind FGF-4–HS in most tissues, as well as in Raji-S1 cells expressing syndecan-1. Proliferation assays using BaF3 cells expressing either FR1c or FR2c support these results. This suggests that FGF and FR recognition of specific HS sulfation patterns is critical for the activation of FGF signaling, and that synthesis of these patterns is regulated during embryonic development