Holistic Inversion of Airborne Electromagnetic Data

A holistic method for simultaneously calibrating, processing, and inverting frequency-domain airborne electromagnetic data has been developed. A spline-based, 3D, layered conductivity model covering a complete survey area is recovered through inversion of an entire raw airborne data set and available independent geoelectric and interface-depth data. The holistic inversion formulation includes a mathematical model to account for systematic calibration errors such as incorrect gain, phase and zero-level. By taking these elements into account in the inversion, the need to pre-process the airborne data prior to inversion is eliminated. Conventional processing schemes involve the sequential application of a number of calibration corrections, with data from each frequency being treated separately. This is followed by inversion of each multi-frequency airborne sample in isolation from other samples. By simultaneously considering all of the available information in a holistic inversion, the inter-frequency and spatial coherency characteristics of the data are able to be exploited. The formulation ensures that the conductivity and calibration models are optimal with respect to the airborne data and prior information. Introduction of inter-frequency inconsistency and multistage error propagation stemming from the sequential nature of conventional processing schemes is also avoided. It is confirmed that accurate conductivity and calibration parameter values are recovered from holistic inversion of synthetic data sets. It is also demonstrated that the results from holistic inversion of raw survey data are superior to the output of conventional 1D inversion of final processed contractor delivered data. In addition to the technical benefits, it is expected that holistic inversion will reduce costs by avoiding the expensive calibration→processing→recalibration paradigm. Furthermore, savings may also be made because specific high altitude zero-level observations, needed for conventional processing, may not be required. The same philosophy is also applied to the inversion of time-domain data acquired by fixed-wing towed-bird systems. A spline-based, 2D, layered conductivity model covering a complete survey line is recovered along with a calibrations model. In this instance, the calibration model is a spline based representation of three unmeasured elements of the system geometry. By inverting the less processed total field data, the procedure is able to prevent incorrect assumptions made in conventional primary field removal from being propagated into the inversion stage. Furthermore, by inverting a complete line of data at once the along-line spatial coherency of the geology and the geometry variations is exploited. Using real survey data, it was demonstrated that all components of the data could be simultaneously and satisfactorily fitted and that the resulting conductivity model was consistent with independent prior information. This was an improvement over the conventional approach, in which the data could not be satisfactorily fitted, nor was the conductivity model consistent with prior information. It was further established that by using the holistic inversion spline parameterization, the resulting conductivity model was more continuous and interpretable than if the conventional style discrete parameterization was used. If adopted, the holistic approach, could reduce survey costs, reduce data processing turnaround times, and improve the quantitative information that can be extracted from data, and hence, increase the value of airborne electromagnetics for mineral exploration and environmental mapping applications.Geoscience Australi

The impact of point mutations in the human androgen receptor : classification of mutations on the basis of transcriptional activity

Peer reviewedPublisher PD

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Does Structural Color Exist in True Fungi?

Structural color occurs by the interaction of light with regular structures and so generates colors by completely different optical mechanisms to dyes and pigments. Structural color is found throughout the tree of life but has not, to date, been reported in the fungi. Here we give an overview of structural color across the tree of life and provide a brief guide aimed at stimulating the search for this phenomenon in fungi

Genetic variation in CFH predicts phenytoin-induced maculopapular exanthema in European-descent patients

Objective To characterize, among European and Han Chinese populations, the genetic predictors of maculopapular exanthema (MPE), a cutaneous adverse drug reaction common to antiepileptic drugs. Methods We conducted a case-control genome-wide association study of autosomal genotypes, including Class I and II human leukocyte antigen (HLA) alleles, in 323 cases and 1,321 drug-tolerant controls from epilepsy cohorts of northern European and Han Chinese descent. Results from each cohort were meta-analyzed. Results We report an association between a rare variant in the complement factor H–related 4 (CFHR4) gene and phenytoin-induced MPE in Europeans (p = 4.5 × 10–11; odds ratio [95% confidence interval] 7 [3.2–16]). This variant is in complete linkage disequilibrium with a missense variant (N1050Y) in the complement factor H (CFH) gene. In addition, our results reinforce the association between HLA-A*31:01 and carbamazepine hypersensitivity. We did not identify significant genetic associations with MPE among Han Chinese patients. Conclusions The identification of genetic predictors of MPE in CFHR4 and CFH, members of the complement factor H–related protein family, suggest a new link between regulation of the complement system alternative pathway and phenytoin-induced hypersensitivity in European-ancestral patients

Spatial distribution of fibropapillomatosis in green turtles along the Queensland coast and an investigation into the influence of water quality on prevalence

Fibropapillomatosis (FP) is a tumor-forming disease which affects all species of marine turtle, but predominantly the green turtle (Chelonia mydas). Expression of this disease is thought to be precipitated by poor environmental conditions and often linked to anthropogenically induced environmental changes. Although FP is a globally distributed disease, targeted studies on the spatial distribution of the disease in Australia are limited. Here, we present the first comprehensive report of FP prevalence in Queensland, Australia. A retrospective analysis of 25,645 capture records for 15 sites along the Queensland coast were used to determine FP prevalence and trends in foraging green turtles. Within this data set, 791 turtles (3.1%) with FP tumors were recorded. Our analysis showed that prevalence varies between sites and years, with juvenile turtles being the most frequently affected by the disease. We found that survey method has a significant influence on the apparent FP prevalence detected at each site. That is, surveys which were explicitly FP-targeted detected higher numbers of individual turtles with FP, and therefore generated higher prevalence rates than comprehensive population surveys. We also report the first attempt at developing water quality indices (WQIs) to compare with FP prevalence data in foraging green turtles. The WQIs were built from metrics published in a range of peer-reviewed papers, reports, and based on expert opinion. Despite utilizing an extensive data set, a relationship between FP prevalence and WQI rankings at each site could not be quantified. The analysis was confounded by a range of limitations, including data gaps, varying temporal scales and data capture methods in the FP prevalence, and water quality data sets. This study has significant implications for management as it highlights the benefits of designing and collecting centralized data that can be integrated and used across multiple projects or programs

Is diabetic retinopathy screening worthwhile among people first diagnosed with diabetes at older ages? A cohort study of Norfolk diabetic retinopathy screening programme

Aims: England's Diabetic Eye Disease Screening Programme offers screening to every resident over age 12 with diabetes, starting as soon as possible after diagnosis and repeated annually. People first diagnosed with diabetes at older ages have shorter life expectancy and therefore may be less likely to benefit from screening and treatment. To inform decisions about whether diabetic eye screening policy should be stratified by age, we investigated the probability of receiving treatment according to age at first screening episode. Methods: This was a cohort study of participants in the Norfolk Diabetic Retinopathy Screening Programme from 2006 to 2017, with individuals' programme data linked to hospital treatment and death data recorded up to 2021. We estimated and compared the probability, annual incidence and screening costs of receiving retinal laser photocoagulation or intravitreal injection and of death, in age groups defined by age at first screening episode. Results: The probability of death increased with increasing age at diagnosis, while the probability of receiving either treatment decreased with increasing age. The estimated cost of screening per person who received either or both treatments was £18,608 among all participants, increasing with age up to £21,721 in those aged 70–79 and £26,214 in those aged 80–89. Conclusions: Diabetic retinopathy screening is less effective and less cost-effective with increasing age at diagnosis of diabetes, because of the increasing probability of death before participants develop sight-threatening diabetic retinopathy and can benefit from treatment. Upper age limits on entry into screening programmes or risk stratification in older age groups may, therefore, be justifiable

Continental-scale animal tracking reveals functional movement classes across marine taxa

Acoustic telemetry is a principle tool for observing aquatic animals, but coverage over large spatial scales remains a challenge. To resolve this, Australia has implemented the Integrated Marine Observing System's Animal Tracking Facility which comprises a continental-scale hydrophone array and coordinated data repository. This national acoustic network connects localized projects, enabling simultaneous monitoring of multiple species over scales ranging from 100 s of meters to 1000 s of kilometers. There is a need to evaluate the utility of this national network in monitoring animal movement ecology, and to identify the spatial scales that the network effectively operates over. Cluster analyses assessed movements and residency of 2181 individuals from 92 species, and identified four functional movement classes apparent only through aggregating data across the entire national network. These functional movement classes described movement metrics of individuals rather than species, and highlighted the plasticity of movement patterns across and within populations and species. Network analyses assessed the utility and redundancy of each component of the national network, revealing multiple spatial scales of connectivity influenced by the geographic positioning of acoustic receivers. We demonstrate the significance of this nationally coordinated network of receivers to better reveal intra-specific differences in movement profiles and discuss implications for effective management