Using LiDAR to Link Forest Canopy Structure with Bat Activity and Insect Occurrence: Preliminary Findings

Bats are an imperiled, yet ecologically-important group of vertebrate predators. Our ongoing research focuses on testing hypotheses about the relationships between the effects of fire on canopy structure and insect prey availability, and how these factors relate to use of foraging space by bats during the pre- and post-hibernation periods at Mammoth Cave National Park (MCNP). LiDAR-derived data (October 2010) were intersected with spatially explicit sampling of bat and insect populations (2010-2011) in order to characterize relationships between canopy structure, insect abundance, and bat activity. A canonical correspondence analysis for bat data suggested that forest canopy structure has a strong relationship with bat activity, particularly for species that echolocate at higher frequencies. Less variation was accounted for in a canonical correspondence analysis of insect occurrence. Even so, this analysis still demonstrated that variation in forest canopy structure influences the insect community at MCNP, albeit in varied ways for specific orders of insects

Evidence for high-frequency oxygenation of Ediacaran shelf seafloor during early evolution of complex life

Increasing oxygenation of the early Ediacaran Ocean is thought to have been responsible for the emergence of early animals. Although geochemical studies have suggested periods of oceanic oxygenation in the Ediacaran, direct evidence for seafloor oxygenation has been lacking. Here, we report frequent occurrences of distinctive, sub-millimetric, and early diagenetic pyrite-marcasite rosettes in phosphorites from the lower Ediacaran Doushantuo Formation (Weng’an, South China). They typically consist of a nucleus of framboidal pyrite, a cortex of radiating marcasite blades intergrown with quartz, and a rim of second-generation pyrite, recording partial oxidative dissolution of pyrite and co-precipitation of marcasite and quartz. This inference is further supported by near-zero carbon isotope values of the host dolostone, similarly low sulfur isotope values for pyrite and marcasite, and evident Fe-isotope fractionation between marcasite and pyrite. Collectively, our findings reveal intermittent bottom-water and porewater oxygenation events, providing direct evidence of high-frequency oxygenation of Ediacaran continental shelves

Widespread occurrences of variably crystalline C-13-depleted graphitic carbon in banded iron formations

Almost all evidence for the oldest traces of life on Earth rely on particles of graphitic carbon preserved in rocks of sedimentary protolith. Yet, the source of carbon in such ancient graphite is debated, as it could possibly be non-biological and/or non-indigenous in origin. Here we describe the co-occurrence of poorly crystalline and crystalline varieties of graphitic carbon with apatite in ten different and variably metamorphosed banded iron formations (BIF) ranging in age from 1,800 to >3,800 Myr. In Neoarchean to Palaeoproterozoic BIF subjected to low-grade metamorphism, C-13-depleted graphitic carbon occurs as inclusions in apatite, and carbonate and arguably represents the remineralisation of syngenetic biomass. In BIF subjected to high-grade metamorphism, C-13-depleted graphite co-occurs with poorly crystalline graphite (PCG), as well as apatite, carbonate, pyrite, amphibole and greenalite. Retrograde minerals such as greenalite, and veins cross-cutting magnetite layers contain PCG. Crystalline graphite can occur with apatite and orthopyroxene, and sometimes it has PCG coatings. Crystalline graphite is interpreted to represent the metamorphosed product of syngenetic organic carbon deposited in BIF, while poorly crystalline graphite was precipitated from C-O-H fluids partially sourced from the syngenetic carbon, along with fluid-deposited apatite and carbonate. The isotopic signature of the graphitic carbon and the distribution of fluid-deposited graphite in highly metamorphosed BIF is consistent with carbon in the fluids being derived from the thermal cracking of syngenetic biomass deposited in BIF, but, extraneous sources of carbon cannot be ruled out as a source for PCG. The results here show that apatite + graphite is a common mineral assemblage in metamorphosed BIF. The mode of formation of this assemblage is, however, variable, which has important implications for the timing of life's emergence on Earth. (C) 2019 Elsevier B.V. All rights reserved.Peer reviewe

Minimal biomass deposition in banded iron formations inferred from organic matter and clay relationships

The cycling of iron and organic matter (OM) is thought to have been a major biogeochemical cycle in the early ferruginous oceans which contributed to the deposition of banded iron formations (BIF). However, BIF are deficient in OM, which is postulated to be the result of near-complete oxidation of OM during iron reduction. We test this idea by documenting the prevalence of OM in clays within BIF and clays in shales associated with BIF. We find in shales >80% of OM occurs in clays, butPeer reviewe

Generalised Elliptic Functions

We consider multiply periodic functions, sometimes called Abelian functions, defined with respect to the period matrices associated with classes of algebraic curves. We realise them as generalisations of the Weierstras P-function using two different approaches. These functions arise naturally as solutions to some of the important equations of mathematical physics and their differential equations, addition formulae, and applications have all been recent topics of study. The first approach discussed sees the functions defined as logarithmic derivatives of the sigma-function, a modified Riemann theta-function. We can make use of known properties of the sigma function to derive power series expansions and in turn the properties mentioned above. This approach has been extended to a wide range of non hyperelliptic and higher genus curves and an overview of recent results is given. The second approach defines the functions algebraically, after first modifying the curve into its equivariant form. This approach allows the use of representation theory to derive a range of results at lower computational cost. We discuss the development of this theory for hyperelliptic curves and how it may be extended in the future.Comment: 16 page

Organic remains in late Palaeoproterozoic granular iron formations and implications for the origin of granules

Toward the end of the Palaeoproterozoic era, over 109 billion tonnes of banded (BIF) and granular (GIF) iron formations were deposited on continental platforms. Granules in iron formations are typically sub-spherical structures 0.2 to 10 mm in size, whereas concretions are >10 mm. Both types of spheroids are preserved throughout the sedimentological record. Their formation has typically been interpreted to originate from reworked Fe-rich sediments in high-energy, wave-agitated, shallow-marine environments. New evidence from six different late Palaeoproterozoic granular iron formations (GIF), however, suggests that some granules are the result of diagenetic reactions, in addition to other features driven by microbial processes and mechanical movements. Characteristic coarse grain interiors and septarian-type cracks inside granules, akin to those features in decimetre- to meter-size concretions, are interpreted as desiccation features from hydrated diagenetic environments where sulphate and/ or ferric iron were reduced while organic matter (OM) was oxidised inside granules. Those granules derived from sulphate reduction preserve diagenetic pyrite rims, whereas those formed via ferric iron reduction preserve diagenetic magnetite along their rims. Other diagenetic minerals including apatite mixed with OM, and various carbonate phases are commonly preserved within granules. Combined with systematically 13C-depleted carbonate, these diagenetic mineral assemblages point to the oxidative decay of OM as a major process involved in the formation of granules. Spheroidal equidistant haematite laminations surround some granules and contain apatite associated with carbonate, OM, and ferric-ferrous silicates, and oxides that further suggest these structures were not shaped by wave-action along sediment-water interfaces, but rather by chemical wave fronts and biomineralisation. Our results demonstrate that the formation mechanisms of GIF also involve microbial activity and chemically-oscillating reactions. As such, granules have excellent potential to be considered as promising biosignatures for studying Precambrian biogeochemistry, as well as astrobiology

Modal Platonism and the problem of negativity.

The Platonic account of modality says, roughly, that truths about alien possibilities are grounded in uninstantiated universals. Recently, Ingram has raised a problem for this kind of view, which is that it apparently requires negative facts to play a truthmaking role. Ingram offers an alternative Platonic account which makes use of modal instantiation relations. In this paper, I highlight some of the costs of Ingram’s new account and argue that a more appealing version of Platonism—and modal theory in general—is one that is supplemented with an ontology of totality facts

Early detection of doxorubicin-induced cardiotoxicity in rats by its cardiac metabolic signature assessed with hyperpolarized MRI.

Doxorubicin (DOX) is a widely used chemotherapeutic agent that can cause serious cardiotoxic side effects culminating in congestive heart failure (HF). There are currently no clinical imaging techniques or biomarkers available to detect DOX-cardiotoxicity before functional decline. Mitochondrial dysfunction is thought to be a key factor driving functional decline, though real-time metabolic fluxes have never been assessed in DOX-cardiotoxicity. Hyperpolarized magnetic resonance imaging (MRI) can assess real-time metabolic fluxes in vivo. Here we show that cardiac functional decline in a clinically relevant rat-model of DOX-HF is preceded by a change in oxidative mitochondrial carbohydrate metabolism, measured by hyperpolarized MRI. The decreased metabolic fluxes were predominantly due to mitochondrial loss and additional mitochondrial dysfunction, and not, as widely assumed hitherto, to oxidative stress. Since hyperpolarized MRI has been successfully translated into clinical trials this opens up the potential to test cancer patients receiving DOX for early signs of cardiotoxicity

A school intervention for 13- to 15-year-olds to prevent dating and relationship violence: the Project Respect pilot cluster RCT

Background ‘Dating and relationship violence’ is intimate partner violence during adolescence. Among dating adolescents in England, 66–75% of girls and 32–50% of boys report victimisation. Multicomponent school-based interventions might reduce dating and relationship violence. We optimised and piloted Project Respect, a new intervention in secondary schools in England, and study methods, to assess the value of a Phase III randomised controlled trial. Objectives To optimise Project Respect and to then conduct a pilot randomised controlled trial in southern England, addressing whether or not progression to a Phase III trial is justified in terms of prespecified criteria. To assess which of two dating and relationship violence scales is optimal, to assess response rates and to consider any necessary refinements. Design Optimisation activities aimed at intervention development and a pilot randomised controlled trial. Setting Optimisation in four secondary schools across southern England, varying by region and local deprivation. A pilot cluster randomised controlled trial in six other such schools (four intervention schools and two control schools), varying by region, attainment and local deprivation. Participants School students in years 8–10 at baseline and staff. Interventions Schools were randomised to the intervention or control arm in a 2 : 1 ratio; intervention comprised staff training, mapping ‘hotspots’ in school for dating and relationship violence, modifying staff patrols, school policy review, informing parents and carers, an application supporting student help-seeking, and a classroom curriculum for students in years 9 and 10 (including student-led campaigns). Main outcome measures Prespecified criteria for progression to Phase III of the trial, concerning acceptability, feasibility, fidelity and response rates. Primary health outcomes were assessed using the Safe Dates and short Conflicts in Adolescent Dating Relationships Inventory measures collected and analysed by individuals who were masked to allocation. Feasibility of economic analysis was assessed. Data sources Baseline and follow-up student and staff surveys, interviews, observations and logbooks. Results The intervention was optimised and approved by the Study Steering Committee. The student response rates in intervention and control groups were 1057 (84.8%) and 369 (76.6%) at baseline, and 1177 (76.8%) and 352 (83.4%) at follow-up, respectively. Safe Dates and the short Conflicts in Adolescent Dating Relationships Inventory had high levels of completion and reliability. At follow-up, prevalence of past-year dating and relationship violence victimisation was around 35% (Safe Dates scale and short Conflicts in Adolescent Dating Relationships Inventory). Staff response rates were very low. Training occurred in all four schools, with suboptimal fidelity. The curriculum was delivered with optimal fidelity in three schools. Other components were delivered inconsistently. Dating and relationship violence was addressed in control schools via violence prevention and responses, but not systematically. Intervention acceptability among students and staff was mixed. An economic evaluation would be feasible. Limitations One school did not undertake baseline surveys. Staff survey response rates were low and completion of the logbook was patchy. Conclusions Our findings suggest that progression to a Phase III trial of this intervention is not indicated because of limited fidelity and acceptability. Future work High prevalence of dating and relationship violence highlights the ongoing need for effective intervention. Potential intervention refinements would include more external support for schools and enhanced curriculum materials. Any future randomised controlled trials could consider having a longer lead-in from randomisation to intervention commencement, using the short Conflicts in Adolescent Dating Relationships Inventory as the primary outcome and not relying on staff surveys. Trial registration Current Controlled Trials ISRCTN65324176. Funding This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 8, No. 5. See the NIHR Journals Library website for further project information

Spontaneous vortices in the formation of Bose-Einstein condensates

Phase transitions are ubiquitous in nature, ranging from protein folding and denaturisation, to the superconductor-insulator quantum phase transition, to the decoupling of forces in the early universe. Remarkably, phase transitions can be arranged into universality classes, where systems having unrelated microscopic physics exhibit identical scaling behaviour near the critical point. Here we present an experimental and theoretical study of the Bose-Einstein condensation phase transition of an atomic gas, focusing on one prominent universal element of phase transition dynamics: the spontaneous formation of topological defects during a quench through the transition. While the microscopic dynamics of defect formation in phase transitions are generally difficult to investigate, particularly for superfluid phase transitions, Bose-Einstein condensates (BECs) offer unique experimental and theoretical opportunities for probing such details. Although spontaneously formed vortices in the condensation transition have been previously predicted to occur, our results encompass the first experimental observations and statistical characterisation of spontaneous vortex formation in the condensation transition. Using microscopic theories that incorporate atomic interactions and quantum and thermal fluctuations of a finite-temperature Bose gas, we simulate condensation and observe vortex formation in close quantitative agreement with our experimental results. Our studies provide further understanding of the development of coherence in superfluids, and may allow for direct investigation of universal phase-transition dynamics.Comment: 14 pages, 6 figures. Accepted for publication in Nature. Supplementary movie files are available at http://www.physics.uq.edu.au/people/mdavis/spontaneous_vortice