A scoping review of metamodeling applications and opportunities for advanced health economic analyses

Introduction: Metamodels, also known as meta-models, surrogate models, or emulators, are used in several fields of research to negate runtime issues with analyzing computational demanding simulation models. This study introduces metamodeling and presents results of a review on metamodeling applications in health economics. Areas covered: A scoping review was performed to identify studies that applied metamodeling methods in a health economic context. After search and selection, 13 publications were found to employ metamodeling methods in health economics. Metamodels were used to perform value of information analysis (n = 5, 38%), deterministic sensitivity analysis (n = 4, 31%), model calibration (n = 1, 8%), probabilistic sensitivity analysis (n = 1), or optimization (n = 1, 8%). One study was found to extrapolate a simulation model to other countries (n = 1, 8%). Applied metamodeling techniques varied considerably between studies, with linear regression being most frequently applied (n = 7, 54%). Expert commentary: Although it has great potential to enable computational demanding analyses of health economic models, metamodeling in health economics is still in its infancy, as illustrated by the limited number of applications and the relatively simple metamodeling methods applied. Comprehensive guidance specific to health economics is needed to provide modelers with the information and tools needed to utilize the full potential of metamodels

Sociocultural dimensions of tuberculosis: an overview of key concepts

Biomedical innovations are unlikely to provide effective and ethical tuberculosis (TB) control measures without complementary social science research. However, a strong interest in interdisciplinary work is often undermined by differences in language and concepts specific to each disciplinary approach. Accordingly, biological and social scientists need to learn how to communicate with each other. This article will outline key concepts relating to TB from medical anthropology and health sociology. Distilling these concepts in an introductory framework is intended to make this material accessible to researchers in laboratory, clinical and fieldwork settings, as well as to encourage more social scientists to engage with TB research among target groups critical for successful programmatic interventions. For pedagogical purposes, the relevant concepts are grouped into three categories: 1) structures and settings, which includes overarching themes such as syndemics, local biologies, medicalisation, structural violence and surveillance; 2) practices and processes, encompassing gender, stigma, taboo, and victim blaming; and 3) experience and enculturation, which includes illness narratives, biographical disruption and dynamic nominalism. By helping to navigate this literature, we hope to foster more cross-disciplinary conversations between qualitative and quantitative researchers. TB, a quintessential social disease, will be controlled more effectively using a multistranded research approach

Ultralow-frequency modulation of whistler-mode wave growth

Measurements from ground-based magnetometers and riometers at auroral latitudes have demonstrated that energetic (~30-300keV) electron precipitation can be modulated in the presence of magnetic field oscillations at ultra-low frequencies. It has previously been proposed that an ultra-low frequency (ULF) wave would modulate field and plasma properties near the equatorial plane, thus modifying the growth rates of whistler-mode waves. In turn, the resulting whistler-mode waves would mediate the pitch-angle scattering of electrons resulting in ionospheric precipitation. In this paper, we investigate this hypothesis by quantifying the changes to the linear growth rate expected due to a slow change in the local magnetic field strength for parameters typical of the equatorial region around 6.6RE radial distance. To constrain our study, we determine the largest possible ULF wave amplitudes from measurements of the magnetic field at geosynchronous orbit. Using nearly ten years of observations from two satellites, we demonstrate that the variation in magnetic field strength due to oscillations at 2mHz does not exceed ±10% of the background field. Modifications to the plasma density and temperature anisotropy are estimated using idealised models. For low temperature anisotropy, there is little change in the whistler-mode growth rates even for the largest ULF wave amplitude. Only for large temperature anisotropies can whistler-mode growth rates be modulated sufficiently to account for the changes in electron precipitation measured by riometers at auroral latitudes

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U–Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P–T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U–Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure

Introduction to metamodeling for reducing computational burden of advanced analyses with health economic models : a structured overview of metamodeling methods in a 6-step application process

Metamodels can be used to reduce the computational burden associated with computationally demanding analyses of simulation models, though applications within health economics are still scarce. Besides a lack of awareness of their potential within health economics, the absence of guidance on the conceivably complex and time-consuming process of developing and validating metamodels may contribute to their limited uptake. To address these issues, this paper introduces metamodeling to the wider health economic audience and presents a process for applying metamodeling in this context, including suitable methods and directions for their selection and use. General (i.e., non-health economic specific) metamodeling literature, clinical prediction modeling literature, and a previously published literature review were exploited to consolidate a process and to identify candidate metamodeling methods. Methods were considered applicable to health economics if they are able to account for mixed (i.e., continuous and discrete) input parameters and continuous outcomes. Six steps were identified as relevant for applying metamodeling methods within health economics, i.e. 1) the identification of a suitable metamodeling technique, 2) simulation of datasets according to a design of experiments, 3) fitting of the metamodel, 4) assessment of metamodel performance, 5) conduct the required analysis using the metamodel, and 6) verification of the results. Different methods are discussed to support each step, including their characteristics, directions for use, key references, and relevant R and Python packages. To address challenges regarding metamodeling methods selection, a first guide was developed towards using metamodels to reduce the computational burden of analyses of health economic models. This guidance may increase applications of metamodeling in health economics, enabling increased use of state-of-the-art analyses, e.g. value of information analysis, with computationally burdensome simulation models

Eliminating latent tuberculosis in low-burden settings: are the principal beneficiaries to be disadvantaged groups or the broader population?

Tuberculosis (TB) remains a leading cause of morbidity and mortality worldwide, and the burdens of this disease continue to track prior disadvantage. In order to galvanise a coordinated global response, WHO has recently launched the End TB Campaign that aims to eliminate TB by 2050. Key to this is the introduction of population screening programmes in low-burden settings to identify and treat people who have latent TB infection (LTBI). The defining features of LTBI are: that it is not an active disease but confers an increased risk of disease; the socially disadvantaged are those most in danger and uncertainty persists as to who will be harmed or benefitted from screening-led prophylactic interventions. Systematic screening programmes that include surveillance, case-finding and treatment of asymptomatic individuals inevitably redistribute the risk of harms and the potential for benefits within a population. The extent to which those targeted within such programmes should be exposed to higher levels of risk in the pursuit of individual or community benefits requires careful consideration prior to implementation. As currently construed, it remains unclear who stands to benefit most from how LTBI screening in high-income countries is being organised, and whose health is being prioritised: members of disadvantaged groups or the broader community. Unless the aims of LTBI screening programmes in these settings are made transparent and their prioritisation ethically justified, there is a significant danger that such a targeted intervention will further disadvantage those who have the least capacity to bear the burdens of TB elimination.NHMRC Centre for Research Excellence in TB Control (CRE 1043225)

A magmatic copper and fluid source for the sediment-hosted Mount Isa deposit

The world class Mount Isa deposit is a unique, sediment-hosted, copper deposit with no known equivalent around the world and a controversial origin. We report δ65Cu values (n = 90) from chalcopyrite grains collected systematically across the entire deposit. The δ65Cu shows a unimodal distribution with limited variability (min = −0.87 ‰; max = 0.88 ‰) and an average value (+0.13 ‰) comparable to average igneous rocks. In general, the δ65Cu values in chalcopyrite are lower near major structures and heavier further away, consistent with equilibrium fractionation with distance from the fluid source. The range in δ65Cu of chalcopyrite from the Mount Isa deposit is less variable compared to sedimentary copper, VMS and porphyry/epithermal deposits, but similar to Michigan deposits; meanwhile, average δ65Cu at Mt. Isa is distinctly higher than sedimentary copper deposits, but similar to VMS, porphyry/epithermal and Michigan deposits. These data suggest that, from a copper isotope perspective, the Mount Isa deposit is clearly different from sedimentary copper deposits and more like VMS, porphyry copper/epithermal and Michigan style deposits. The average δ65Cu (+0.13 ‰) is almost identical to the average δ65Cu (+0.14 ‰) from Proterozoic basalts and suggests that copper was sourced from the underlying mafic rocks; the limited fractionation and the normal distribution of the δ65Cu indicate a very effective leaching mechanism and transport by a hot fluid from which chalcopyrite precipitated without significant fractionation of copper isotopes

Integrative concepts and practices of health in transdisciplinary social ecology

Increasing recognition of interdependencies of the health of humans, other organisms and ecosystems, and of their importance to socio-ecological systems, necessitates application of integrative concepts such as One Health and EcoHealth. These concepts open new perspectives for research and practice but also generate confusion and divergent opinion, prompting new theories, and call for empirical clarification and evaluation. Through a semi-systematic evaluation of knowledge generation in scientific publications (comprised of literature reviews, conceptual models and analyses of communities of practice), we show how integrative concepts and approaches to health evolve and are adopted. Our findings indicate that while their contexts, goals and rationales vary, integrative concepts of health essentially arise from shared interests in living systems. Despite recent increased attention to ecological and societal aspects of health including broader sustainability issues, the focus remains anthropocentric and oriented towards biomedicine. Practices reflect and in turn transform these concepts, which together with practices also influence ways of integration. Overarching narratives vary between optimism and pessimism towards integrated health and knowledge. We conclude that there is an urgent need for better, coherent and more deeply integrative health concepts, approaches and practices to foster the well-being of humans, other animals and ecosystems. Consideration of these concepts and practices has methodological and political importance, as it will transform thinking and action on both society and nature and specifically can enrich science and practice, expanding their scope and linking them better. Transdisciplinary efforts are crucial to developing such concepts and practices to properly address the multiple facets of health and to achieve their appropriate integration for the socio-ecological systems at stake. We propose the term “transdisciplinary health” to denote the new approaches needed