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Development and validation of a prediction score for critical admission in children with dengue
Get PDFObjectives: This study aimed to develop and validate a clinical score for the prediction of critical care entrance in children with dengue.
Methods: We conducted a retrospective cohort study using admissions from January 2019 to August 2021, at Hospital Infantil Napoleón Franco Pareja, in Cartagena, Colombia. We included all children 18 years or younger, with a positive immunoglobulin M or nonstructural protein 1 laboratory test and admitted for follow-up at the emergency department. We selected variables retrospectively collected on emergency admission for feature selection. We assessed discrimination and calibration in the development dataset, using 1000 bootstrap replications for internal validation. Data from 2019 to 2020 were used for development and 2021 for temporal validation. We report the c-statistic for discrimination with 95% confidence intervals (CIs), as well as the calibration intercept and slope.
Results: One thousand three hundred eighty-five patients were included for development and internal validation. In temporal validation with 519 additional patients, the c-statistic was 0.82 (95% CI: 0.77–0.87), with a calibration slope of 0.98 (95% CI: 0.77–1.18). We selected the 50th percentile of the distribution of predicted probability of critical care entrance (5%) as a threshold value for increased alert at emergency admission, missing 10% of all cases that need to enter critical care (sensitivity of 90% with 95% CI of 82–95, and specificity of 48% with 95% CI of 41–50).
Conclusions: Our validated model can be useful to predict critical care entrance in children with dengue. We recommend the validation and potential recalibration of our score in other clinical settings
Search for Higgs boson decays into a pair of pseudoscalar particles in the γγτ had τ had final state using pp collisions at s = 13 TeV with the ATLAS detector
Get PDFA search for exotic decays of the 125 GeV Higgs boson into a pair of new spin-0 particles, H → aa, where one decays into a photon pair and the other into a τ-lepton pair, is presented. Hadronic decays of the τ-leptons are considered and reconstructed using a dedicated tagger for collimated τ-lepton pairs. The search uses 140 fb−1 of proton-proton collision data at a centre-of-mass energy of s = 13 TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the a boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95% confidence level are set on the branching ratio of the Higgs boson to the γγττ final state, B(H → aa → γγττ), ranging from 0.2% to 2%, depending on the a-boson mass hypothesis
Scaling fixed field accelerators: theory and modelling of horizontal- and vertical-excursion accelerators
Get PDFFixed Field Accelerators, or FFAs, are accelerators that use time-independent magnetic fields, permitting the orbit to move as the beam is accelerated. Spatially-dependent magnetic fields allow for the control of orbit geometry during acceleration and the control of focussing strength along the orbit. Scaling FFAs represent the subset of fixed field accelerators in which the magnetic fields follow scaling laws that ensure geometric similarity between closed orbits of different energies and energy-independent focussing behaviour. Vertical-excursion FFAs (vFFAs) present a novel variant on the scaling FFA template where higher-energy orbits are vertically translated copies of lower energy ones, introducing complexities in optics and orbits due to coupled particle motion across the two transverse planes and non-planar orbit behaviour. Because of this, previous design and study of vFFA rings has depended entirely on numerical integration methods.
This study presents analytical methods for studying optics in both horizontal- and vertical-excursion FFAs, deriving for the first time an analytic model of the vFFA. A multipole decomposition approach, termed ‘harmonic analysis,’ is developed to study vFFA optics in cases where the analytic model has limitations. This technique is then further used in the study of nonlinear (higher-order) effects in conventional FFAs beyond the capabilities of the linear analytic modelling. The nonlinear effects studies are additionally benchmarked with experimental studies of amplitude-dependent tune shift, showing good agreement. To demonstrate the strength of the newly-developed analytic techniques, the vFFA as a muon accelerator stage for a muon collider is studied, where insights provided by the analytic model enable an optimisation that was not previously possible
A two‐in‐one strategy to simultaneously boost the site density and turnover frequency of Fe−N−C oxygen reduction catalysts
Get PDFSite density (SD) and turnover frequency (TOF) are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron-nitrogen-carbon (Fe−N−C) catalysts that represent the most promising alternatives to precious and scarce platinum. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe−N−C catalyst. Here we show that treating a typical Fe−N−C catalyst with ammonium iodine (NH4I) vapor via a one-step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in situ released NH3, but also regulates the electronic structure of the Fe−N−C moieties by the iodine dopants incorporated into the carbon matrix. As a result, the NH4I-treated Fe−N−C catalyst possesses both high values in the SD of 2.15×1019 sites g−1 (×2 enhancement compared to the untreated counterpart) and TOF of 3.71 electrons site−1 s−1 (×3 enhancement) that correspond to a high mass activity of 12.78 A g−1, as determined by in situ nitrite stripping technique. Moreover, this catalyst exhibits an excellent oxygen reduction activity in base with a half-wave potential (E1/2) of 0.924 V and acceptable activity in acid with E1/2 =0.795 V, and superior power density of 249.1 mW cm−2 in a zinc-air battery
Facilitators and barriers faced by community organizations supporting older adults during the COVID-19 pandemic
Get PDFBackground: During the COVID-19 pandemic, olderadult-focused community organizations played an essential role in supporting the wellbeing of older adults. Supporting older adults during this time required extensive modifications to existing programming but their adaptations during the COVID-19 pandemic are not well documented. The purpose of this study was to understand how older adult-focused community organizations adopted virtual delivery formats during the COVID-19 pandemic and their perspectives of the barriers and facilitators for organizations and older adults. Methods: To understand the changes that were made, we conducted a qualitative environmental scan of community-based services across British Columbia. Online searches were complemented by snowball sampling and key informant interviews. We identified 90 older adult-serving community organizations and interviewed 26. We used reflexive thematic analysis to understand the main strategies. Results: These community organizations described barriers related to older adults’ wellbeing, information technology proficiency, and personal/organizational losses related to changes in program structure. Facilitators for virtual activities and events included inter- and intra-organizational collaboration, intrinsic qualities of program design, physical resources to supporting virtual programming, and availability of technological resources. Organizations described meeting the challenge by increasing the ‘depth’ and ‘breadth’ of their reach. Conclusion: Older adult-focused community organizations recognized the critical role they played for older adults and adapted their resources to meet those needs. Informational technology was quickly and effectively leveraged to promote social interaction for older adults when physical distancing was required during the COVID-19 pandemic. Barriers related to cost, time, and ultimately older adults’ interest in a virtual delivery format were critical limitations. Graphical Abstract
Identifying extra pulmonary vein targets for persistent atrial fibrillation ablation: bridging advanced and conventional mapping techniques
Get PDFAims: Advanced technologies such as charge density mapping (CDM) show promise in guiding adjuvant ablation in patients with persistent atrial fibrillation (AF); however, their limited availability restricts widespread adoption. We sought to determine whether regions of the left atrium containing CDM-identified pivoting and rotational propagation patterns during AF could also be reliably identified using more conventional contact mapping techniques. Methods and results: Twenty-two patients undergoing de novo ablation of persistent AF underwent both CDM and electroanatomic voltage mapping during AF and sinus rhythm with multiple pacing protocols. Through the use of a left atrium statistical shape model, the location of distinctive propagation patterns identified by CDM was compared with low-voltage areas (LVAs) and regions of slow conduction velocity (CV). Neither LVA nor CV mapping during paced rhythms reliably identified regions containing CDM propagation patterns. Conduction velocity mapping during AF did correlate with these regions (ρ = −0.63, P < 0.0001 for pivoting patterns; ρ = −0.54, P < 0.0001 for rotational patterns). These propagation patterns consistently occurred in two specific anatomical regions across patients: the anteroseptal and inferoposterior walls of the left atrium. Conclusion: Mapping techniques during paced rhythms do not reliably correspond with regions of CDM-identified propagation patterns in persistent AF. However, these propagation patterns are consistently observed in two specific anatomical regions, suggesting a predisposition to abnormal electrophysiological properties. While further research is needed, these regions may serve as promising targets for empirical ablation, potentially reducing the reliance on complex mapping techniques
Densities of the endangered large blue butterfly Phengaris arion vary by 100-fold in restored conservation grasslands, providing a tool to prioritise future introductions
Get PDFA long-term study was made of the carrying capacities (K) of UK grasslands restored to support the endangered butterfly Phengaris arion. This iconic species is the focus of major restoration programmes and provides a blueprint for the conservation of other threatened insects.
Phengaris arion larvae are phytophagous during their early instars before switching to become obligate social parasites of Myrmica ant colonies for their main growth. A mechanistic model, incorporating life-table measurements of natality and mortalities, was used to predict the value of K on 19 restorations. Predictions were compared with actual butterfly densities measured for up to 33 consecutive generations per site over 43 years.
The model suggested that individual sites vary by up to a hundred-fold in the density of butterflies each would support. Observed densities closely correlated with model predictions, with the most productive site supporting 129 times more butterflies per square metre than the least productive one.
Of seven life-table parameters modelled, the three that explained observed butterfly densities best describe the distribution and fitness of its primary host ant species, Myrmica sabuleti. Population densities correlated most closely with the density of host ant nests.
Annual fluctuations in P. arion numbers attributable to the weather were one to two orders of magnitude lower than the differences between site carrying capacity densities. Even extreme events, such as drought, caused perturbations one order of magnitude smaller than inter-site carrying capacity variations.
Synthesis and applications. Observed population dynamics of P. arion conform with theories of a definable ceiling for insect numbers, controlled by density dependence and limited by a larval resource that is typically more specialised and rarer within sites than was once perceived. At a practical level, the model provides a useful tool for determining which future sites should be prioritised for the persistence of this endangered species and for new restorations. More generally, the results support two concepts: (i) once suitable management has been implemented, effects of intrinsic site characteristics on numbers greatly exceed interannual fluctuations; and (ii) understanding how the quality of larval habitat varies between sites is paramount when restoring the size and resilience of populations of declining invertebrates
The ancient world: us and them
Get PDFThis chapter takes three plant types – the shady tree, the happy crop, and the wayside flower – as starting points for an exploration of ancient attitudes towards plants as both in harmony with and divergent from human worldviews and goals. It demonstrates how the same or similar plants can represent very different moods in different settings, sometimes positively reinforcing a human view, sometimes obstructing it. The connection between the sense of a human lifespan and the longevity or brevity of plants’ lives is forged and reforged in different contexts, while very human concerns with morality and aesthetics are differently projected onto these three broad categories of plant. Ranging from the earliest Greek works to the mid-imperial period of Rome, the chapter highlights both some continuities and some differences emerging in the course of around 900 years of literary engagement with plants
Transient destabilization of whole brain dynamics induced by N,N-Dimethyltryptamine (DMT)
Get PDFThe transition towards the brain state induced by psychedelic drugs is frequently neglected in favor of a static description of their acute effects. We use a time-dependent whole-brain model to reproduce large-scale brain dynamics measured with fMRI from 15 volunteers under 20 mg intravenous N,N-Dimethyltryptamine (DMT), a short-acting psychedelic. To capture its transient effects, we parametrize the proximity to a global bifurcation using a pharmacokinetic equation. Simulated perturbations reveal a transient of heightened reactivity concentrated in fronto-parietal regions and visual cortices, correlated with serotonin 5HT2a receptor density, the primary target of psychedelics. These advances suggest a mechanism to explain key features of the psychedelic state and also predicts that the temporal evolution of these features aligns with pharmacokinetics. Our results contribute to understanding how psychedelics introduce a transient where minimal perturbations can achieve a maximal effect, shedding light on how short psychedelic episodes may extend an overarching influence over time
