Publications by authors named "David Newell"

The fungal disease chytridiomycosis (causative agent Batrachochytrium dendrobatidis [Bd]) is a primary contributor to amphibian species declines. The morphological and physiological reorganization that occurs during amphibian metamorphosis likely increases the vulnerability of metamorphs to Bd. To address this, we exposed pro-metamorphic tadpoles of Fleay's barred frog (Mixophyes fleayi) to Bd and sampled skin and liver sections from control and exposed animals throughout metamorphosis (Gosner stages 40, 42 and 45).

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Article Synopsis
  • - The paper explores the quantum anomalous Hall (QAH) effect in a resistor made from Chromium-doped Bismuth Antimony Telluride, aimed at linking it with a programmable Josephson voltage standard (PJVS) without using a magnetic field.
  • - Precision measurements of the QAH resistance were conducted while applying a microwave signal to the PJVS, which enhances the accuracy of the resistance readings.
  • - The findings aim to enhance experimental setups for combining various quantum electrical standards into one cohesive system, which could lead to advancements in quantum technology.
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Accurate and continuous monitoring of cerebral blood flow is valuable for clinical neurocritical care and fundamental neurovascular research. Transcranial Doppler (TCD) ultrasonography is a widely used non-invasive method for evaluating cerebral blood flow, but the conventional rigid design severely limits the measurement accuracy of the complex three-dimensional (3D) vascular networks and the practicality for prolonged recording. Here we report a conformal ultrasound patch for hands-free volumetric imaging and continuous monitoring of cerebral blood flow.

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Amphibian populations are undergoing extensive declines globally. The fungal disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), is a primary contributor to these declines. The amphibian metamorphic stages (Gosner stages 42-46) are particularly vulnerable to a range of stressors, including Bd.

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This work reports the experimental demonstration of single-slit diffraction exhibited by electrons propagating in encapsulated graphene with an effective de Broglie wavelength corresponding to their attributes as massless Dirac fermions. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were also utilized to readily understand the observations reported.

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Background: Databases have become an important tool in understanding trends and correlations in health care by collecting demographic and clinical information. Analysis of data collected from large cohorts of patients can have the potential to generate insights into factors identifying treatments and the characteristics of subgroups of patients who respond to certain types of care. The Care Response (CR) database was designed to capture patient-reported outcome measures (PROMs) for chiropractic patients internationally.

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Global change is causing an unprecedented restructuring of ecosystems, with the spread of invasive species being a key driver. While population declines of native species due to invasives are well documented, much less is known about whether new biotic interactions reshape niches of native species. Here we quantify geographic range and realized-niche contractions in Australian frog species following the introduction of amphibian chytrid fungus Batrachochytrium dendrobatidis, a pathogen responsible for catastrophic amphibian declines worldwide.

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The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused catastrophic frog declines on several continents, but disease outcome is mediated by a number of factors. Host life stage is an important consideration and many studies have highlighted the vulnerability of recently metamorphosed or juvenile frogs compared to adults. The majority of these studies have taken place in a laboratory setting, and there is a general paucity of longitudinal field studies investigating the influence of life stage on disease outcome.

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Deepening droughts and unprecedented wildfires are at the leading edge of climate change. Such events pose an emerging threat to species maladapted to these perturbations, with the potential for steeper declines than may be inferred from the gradual erosion of their climatic niche. This study focused on two species of amphibians- and (Limnodynastidae)-from the Gondwanan rainforests of eastern Australia that were extensively affected by the "Black Summer" megafires of 2019/2020 and the severe drought associated with them.

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The dynamics of a swinging payload suspended from a stationary crane, an unwanted phenomenon on a construction site, can be described as a simple pendulum. However, an experienced crane operator can deliver a swinging payload and have it stop dead on target in a finite amount of time by carefully modulating the speed of the trolley. Generally, a series of precisely timed stop and go movements of the trolley are implemented to damp out the kinetic energy of the simple harmonic oscillator.

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Montane ecosystems cover approximately 20% of the Earth's terrestrial surface and are centres of endemism. Globally, anthropogenic climate change is driving population declines and local extinctions across multiple montane taxa, including amphibians. We applied the maximum entropy approach to predict the impacts of climate change on the distribution of two poorly known amphibian species (Philoria kundagungan and Philoria richmondensis) endemic to the subtropical uplands of the Gondwana Rainforests of Australia, World Heritage Area (GRAWHA).

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Photocurrent (PC) measurements can reveal the relaxation dynamics of photoexcited hot carriers beyond the linear response of conventional transport experiments, a regime important for carrier multiplication. Here, we study the relaxation of carriers in graphene in the quantum Hall regime by accurately measuring the PC signal and modeling the data using optical Bloch equations. Our results lead to a unified understanding of the relaxation processes in graphene over different magnetic field strength regimes, which is governed by the interplay of Coulomb interactions and interactions with acoustic and optical phonons.

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Objectives: An audible pop is the sound that can derive from an adjustment in spinal manipulative therapy and is often seen as an indicator of a successful treatment. A review conducted in 1998 concluded that there was little scientific evidence to support any therapeutic benefit derived from the audible pop. Since then, research methods have evolved considerably creating opportunities for new evidence to emerge.

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Novel infectious diseases, particularly those caused by fungal pathogens, pose considerable risks to global biodiversity. The amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) has demonstrated the scale of the threat, having caused the greatest recorded loss of vertebrate biodiversity attributable to a pathogen. Despite catastrophic declines on several continents, many affected species have experienced population recoveries after epidemics.

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Article Synopsis
  • Amphibians are losing their numbers fast because of diseases like chytridiomycosis, which is caused by harmful fungi.
  • The time when amphibians change from tadpoles to adults (metamorphosis) is when they are especially weak against this disease.
  • Scientists need to do more research on how amphibians fight off diseases during this change and suggest better ways to protect them, especially in areas where the harmful fungi are common.
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Objective: Recently published studies have described slow spontaneous cerebral blood flow (CBF) and cerebrospinal fluid (CSF) oscillations measured by magnetic resonance imaging (MRI) as potential drivers of brain glymphatic flow, with a similar frequency as intracranial B-waves. Aiming to establish the relationship between these waveforms, we performed additional analysis of frequency and waveform parameters, of our previously published transcranial Doppler (TCD) and intracranial pressure (ICP) recordings of intracranial B waves, to compare to published MRI frequency measurements of CBF and CSF slow oscillations.

Patients And Methods: We analyzed digital recordings of B waves in 29 patients with head injury, including middle cerebral artery (MCA) flow velocity (FV), ICP, end tidal CO, and arterial blood pressure (ABP).

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The nonclassical extracellular signal-related kinase 5 (ERK5) mitogen-activated protein kinase pathway has been implicated in increased cellular proliferation, migration, survival, and angiogenesis; hence, ERK5 inhibition may be an attractive approach for cancer treatment. However, the development of selective ERK5 inhibitors has been challenging. Previously, we described the development of a pyrrole carboxamide high-throughput screening hit into a selective, submicromolar inhibitor of ERK5 kinase activity.

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The six species of mountain frogs (Philoria: Limnodynastidae: Anura) are endemic to south-eastern Australia. Five species occur in headwater systems in mountainous north-eastern New South Wales (NSW) and south-eastern Queensland (Qld), centred on the Gondwana Rainforests of Australia World Heritage Area. A previous molecular genetic analysis identified divergent genetic lineages in the central and western McPherson Ranges region of Qld and NSW, but sampling was inadequate to test the species status of these lineages.

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Decoherence in quantum bits (qubits) is a major challenge for realizing scalable quantum computing. One of the primary causes of decoherence in qubits and quantum circuits based on superconducting Josephson junctions is the critical current fluctuation. Many efforts have been devoted to suppressing the critical current fluctuation in Josephson junctions.

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Quantum Boltzmann formalism is employed to study the transport properties of strongly-coupled double layer systems that enable the formation of interlayer excitons and exciton condensation. The importance of exciton formation, dissociation, and condensation is highlighted in the context of thermoelectric power generation, and this mathematical inquiry provides an alternative methodology to calculate the thermoelectric efficiency given the conditions of exciton formation. The Onsager relation for the Coulomb drag resistivity is shown to be valid even when exciton condensation is present.

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Here, we report the effects of enhanced magnetic fields resulting from type-II superconducting NbTiN slabs adjacent to narrow Hall bar devices fabricated from epitaxial graphene. Observed changes in the magnetoresistances were found to have minimal contributions from device inhomogeneities, magnet hysteresis, electron density variations along the devices, and transient phenomena. We hypothesize that Abrikosov vortices, present in type-II superconductors, contribute to these observations.

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Background: Chronic widespread pain (CWP) including fibromyalgia has a prevalence of up to 15% and is associated with substantial morbidity. Supporting psychosocial and behavioural self-management is increasingly important for CWP, as pharmacological interventions show limited benefit. We systematically reviewed the effectiveness of interventions applying self-management principles for CWP including fibromyalgia.

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As first recognized in 2010, epitaxial graphene on SiC(0001) provides a platform for quantized Hall resistance (QHR) metrology unmatched by other two-dimensional structures and materials. Here we report graphene parallel QHR arrays, with metrologically precise quantization near 1000 Ω. These arrays have tunable carrier densities, due to uniform epitaxial growth and chemical functionalization, allowing quantization at the robust = 2 filling factor in array devices at relative precision better than 10.

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