In-plane fluxon in layered superconductors with arbitrary number of layers

I derive an approximate analytic solution for the in-plane vortex (fluxon) in layered superconductors and stacked Josephson junctions (SJJ's) with arbitrary number of layers. The validity of the solution is verified by numerical simulation. It is shown that in SJJ's with large number of thin layers, phase/current and magnetic field of the fluxon are decoupled from each other. The variation of phase/current is confined within the Josephson penetration depth, $\lambda_J$, along the layers, while magnetic field decays at the effective London penetration depth, $\lambda_c \gg \lambda_J$. For comparison with real high-$T_c$ superconducting samples, large scale numerical simulations with up to 600 SJJ's and with in-plane length up to 4000 $\lambda_J$%, are presented. It is shown, that the most striking feature of the fluxon is a Josephson core, manifesting itself as a sharp peak in magnetic induction at the fluxon center.Comment: 4 pages, 4 figures. Was presented in part at the First Euroconference on Vortex Matter in Superconductors (Crete, September 1999

Optical fibre-enabled photoswitching for localised activation of an anti-cancer therapeutic drug

Local activation of an anti-cancer drug when and where needed can improve selectivity and reduce undesirable side effects. Photoswitchable drugs can be selectively switched between active and inactive states by illumination with light; however, the clinical development of these drugs has been restricted by the difficulty in delivering light deep into tissue where needed. Optical fibres have great potential for light delivery in vivo, but their use in facilitating photoswitching in anti-cancer compounds has not yet been explored. In this paper, a photoswitchable chemotherapeutic is switched using an optical fibre, and the cytotoxicity of each state is measured against HCT-116 colorectal cancer cells. The performance of optical-fibre-enabled photoswitching is characterised through its dose response. The UV–Vis spectra confirm light delivered by an optical fibre effectively enables photoswitching. The activated drug is shown to be twice as effective as the inactive drug in causing cancer cell death, characterised using an MTT assay and fluorescent microscopy. This is the first study in which a photoswitchable anti-cancer compound is switched using an optical fibre and demonstrates the feasibility of using optical fibres to activate photoswitchable drugs for potential future clinical applications.Kathryn A. Palasis, Noor A. Lokman, Bryden C. Quirk, Alaknanda Adwal, Loretta Scolaro, Weikun Huang, Carmela Ricciardelli, Martin K. Oehler, Robert A. McLaughlin and Andrew D. Abel

Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid with Self-Gravity

In various astrophysical contexts, we analyze self-similar behaviours of magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized gas under self-gravity with the specific entropy conserved along streamlines. In particular, this MHD model analysis frees the scaling parameter $n$ in the conventional polytropic self-similar transformation from the constraint of $n+\gamma=2$ with $\gamma$ being the polytropic index and therefore substantially generalizes earlier analysis results on polytropic gas dynamics that has a constant specific entropy everywhere in space at all time. On the basis of the self-similar nonlinear MHD ordinary differential equations, we examine behaviours of the magnetosonic critical curves, the MHD shock conditions, and various asymptotic solutions. We then construct global semi-complete self-similar MHD solutions using a combination of analytical and numerical means and indicate plausible astrophysical applications of these magnetized flow solutions with or without MHD shocks.Comment: 21 pages, 7 figures, accepted for publication in APS

Extracorporeal Membrane Oxygenation Characteristics and Outcomes in Children and Adolescents With COVID-19 or Multisystem Inflammatory Syndrome Admitted to U.S. ICUs

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) has been used successfully to support adults with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related cardiac or respiratory failure refractory to conventional therapies. Comprehensive reports of children and adolescents with SARS-CoV-2-related ECMO support for conditions, including multisystem inflammatory syndrome in children (MIS-C) and acute COVID-19, are needed. Design: Case series of patients from the Overcoming COVID-19 public health surveillance registry. SETTING: Sixty-three hospitals in 32 U.S. states reporting to the registry between March 15, 2020, and December 31, 2021. PATIENTS: Patients less than 21 years admitted to the ICU meeting Centers for Disease Control criteria for MIS-C or acute COVID-19. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The final cohort included 2,733 patients with MIS-C (n = 1,530; 37 [2.4%] requiring ECMO) or acute COVID-19 (n = 1,203; 71 [5.9%] requiring ECMO). ECMO patients in both groups were older than those without ECMO support (MIS-C median 15.4 vs 9.9 yr; acute COVID-19 median 15.3 vs 13.6 yr). The body mass index percentile was similar in the MIS-C ECMO versus no ECMO groups (89.9 vs 85.8; p = 0.22) but higher in the COVID-19 ECMO versus no ECMO groups (98.3 vs 96.5; p = 0.03). Patients on ECMO with MIS-C versus COVID-19 were supported more often with venoarterial ECMO (92% vs 41%) for primary cardiac indications (87% vs 23%), had ECMO initiated earlier (median 1 vs 5 d from hospitalization), shorter ECMO courses (median 3.9 vs 14 d), shorter hospital length of stay (median 20 vs 52 d), lower in-hospital mortality (27% vs 37%), and less major morbidity at discharge in survivors (new tracheostomy, oxygen or mechanical ventilation need or neurologic deficit; 0% vs 11%, 0% vs 20%, and 8% vs 15%, respectively). Most patients with MIS-C requiring ECMO support (87%) were admitted during the pre-Delta (variant B.1.617.2) period, while most patients with acute COVID-19 requiring ECMO support (70%) were admitted during the Delta variant period. Conclusions: ECMO support for SARS-CoV-2-related critical illness was uncommon, but type, initiation, and duration of ECMO use in MIS-C and acute COVID-19 were markedly different. Like pre-pandemic pediatric ECMO cohorts, most patients survived to hospital discharge

Altered white matter microstructural organization in posttraumatic stress disorder across 3047 adults: results from the PGC-ENIGMA PTSD consortium

A growing number of studies have examined alterations in white matter organization in people with posttraumatic stress disorder (PTSD) using diffusion MRI (dMRI), but the results have been mixed which may be partially due to relatively small sample sizes among studies. Altered structural connectivity may be both a neurobiological vulnerability for, and a result of, PTSD. In an effort to find reliable effects, we present a multi-cohort analysis of dMRI metrics across 3047 individuals from 28 cohorts currently participating in the PGC-ENIGMA PTSD working group (a joint partnership between the Psychiatric Genomics Consortium and the Enhancing NeuroImaging Genetics through Meta-Analysis consortium). Comparing regional white matter metrics across the full brain in 1426 individuals with PTSD and 1621 controls (2174 males/873 females) between ages 18-83, 92% of whom were trauma-exposed, we report associations between PTSD and disrupted white matter organization measured by lower fractional anisotropy (FA) in the tapetum region of the corpus callosum (Cohen's d = -0.11, p = 0.0055). The tapetum connects the left and right hippocampus, for which structure and function have been consistently implicated in PTSD. Results were consistent even after accounting for the effects of multiple potentially confounding variables: childhood trauma exposure, comorbid depression, history of traumatic brain injury, current alcohol abuse or dependence, and current use of psychotropic medications. Our results show that PTSD may be associated with alterations in the broader hippocampal network.New methods for child psychiatric diagnosis and treatment outcome evaluatio

Study of Z → llγ decays at √s = 8 TeV with the ATLAS detector

This paper presents a study of Z → llγ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20.2 fb−1 collected at a centre-ofmass energy √s = 8 TeV. Integrated fiducial cross-sections together with normalised differential fiducial cross-sections, sensitive to the kinematics of final-state QED radiation, are obtained. The results are found to be in agreement with stateof-the-art predictions for final-state QED radiation. First measurements of Z → llγ γ decays are also reported

Constraints on spin-0 dark matter mediators and invisible Higgs decays using ATLAS 13 TeV pp collision data with two top quarks and missing transverse momentum in the final state

This paper presents a statistical combination of searches targeting final states with two top quarks and invisible particles, characterised by the presence of zero, one or two leptons, at least one jet originating from a b-quark and missing transverse momentum. The analyses are searches for phenomena beyond the Standard Model consistent with the direct production of dark matter in pp collisions at the LHC, using 139 fb−1 of data collected with the ATLAS detector at a centre-of-mass energy of 13 TeV. The results are interpreted in terms of simplified dark matter models with a spin-0 scalar or pseudoscalar mediator particle. In addition, the results are interpreted in terms of upper limits on the Higgs boson invisible branching ratio, where the Higgs boson is produced according to the Standard Model in association with a pair of top quarks. For scalar (pseudoscalar) dark matter models, with all couplings set to unity, the statistical combination extends the mass range excluded by the best of the individual channels by 50 (25) GeV, excluding mediator masses up to 370 GeV. In addition, the statistical combination improves the expected coupling exclusion reach by 14% (24%), assuming a scalar (pseudoscalar) mediator mass of 10 GeV. An upper limit on the Higgs boson invisible branching ratio of 0.38 (0.30+0.13−0.09) is observed (expected) at 95% confidence level

Software performance of the ATLAS track reconstruction for LHC run 3

Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pileup) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60 pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two

Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb−1 of proton–proton collisions at s√ = 13 TeV with the ATLAS detector

A search for pair production of doubly charged Higgs bosons (H±± ), each decaying into a pair of prompt, isolated, and highly energetic leptons with the same electric charge, is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb−1 recorded by the ATLAS detector during Run 2 of the Large Hadron Collider (LHC). This analysis focuses on same-charge leptonic decays, H±±→ℓ±ℓ′± where ℓ,ℓ′=e,μ,τ, in two-, three-, and four-lepton channels, but only considers final states which include electrons or muons. No evidence of a signal is observed. Corresponding upper limits on the production cross-section of a doubly charged Higgs boson are derived, as a function of its mass m(H±±), at 95% confidence level. Assuming that the branching ratios to each of the possible leptonic final states are equal, B(H±±→e±e±)=B(H±±→e±μ±)=B(H±±→μ±μ±)=B(H±±→e±τ±)=B(H±±→μ±τ±)=B(H±±→τ±τ±)=1/6, the observed (expected) lower limit on the mass of a doubly charged Higgs boson is 1080 GeV (1065 GeV) within the left-right symmetric type-II seesaw model, which is the strongest limit to date produced by the ATLAS Collaboration. Additionally, this paper provides the first direct test of the Zee–Babu neutrino mass model at the LHC, yielding an observed (expected) lower limit of m(H±±) = 900 GeV (880 GeV)

Deep generative models for fast photon shower simulation in ATLAS

The need for large-scale production of highly accurate simulated event samples for the extensive physics programme of the ATLAS experiment at the Large Hadron Collider motivates the development of new simulation techniques. Building on the recent success of deep learning algorithms, variational autoencoders and generative adversarial networks are investigated for modelling the response of the central region of the ATLAS electromagnetic calorimeter to photons of various energies. The properties of synthesised showers are compared with showers from a full detector simulation using geant4. Both variational autoencoders and generative adversarial networks are capable of quickly simulating electromagnetic showers with correct total energies and stochasticity, though the modelling of some shower shape distributions requires more refinement. This feasibility study demonstrates the potential of using such algorithms for ATLAS fast calorimeter simulation in the future and shows a possible way to complement current simulation techniques