Entangled photons from the polariton vacuum in a switchable optical cavity

We study theoretically the entanglement of two-photon states in the ground state of the intersubband cavity system, the so-called polariton vacuum. The system consists of a sequence of doped quantum wells located inside a microcavity and the photons can interact with intersubband excitations inside the quantum wells. Using an explicit solution for the ground state of the system, operated in the ultrastrong coupling regime, a post-selection is introduced, where only certain two-photon states are considered and analyzed for mode entanglement. We find that a fast quench of the coupling creates entangled photons and that the degree of entanglement depends on the absolute values of the in-plane wave vectors of the photons. Maximally entangled states can be generated by choosing the appropriate modes in the post-selection.Comment: 9+ pages, 7 figure

Tuning domain wall velocity with Dzyaloshinskii-Moriya interaction

We have studied a series of Pt/Co/M epitaxial trilayers, in which Co is sandwiched between Pt and a non magnetic layer M (Pt, Ir, Cu, Al). Using polar magneto-optical Kerr microscopy, we show that the field- induced domain wall speeds are strongly dependent on the nature of the top layer, they increase going from M=Pt to lighter top metallic overlayers, and can reach several 100 m/s for Pt/Co/Al. The DW dynamics is consistent with the presence of chiral N\'eel walls stabilized by interfacial Dzyaloshinskii-Moriya interaction (DMI) whose strength increases going from Pt to Al top layers. This is explained by the presence of DMI with opposite sign at the Pt/Co and Co/M interfaces, the latter increasing in strength going towards heavier atoms, possibly due to the increasing spin-orbit interaction. This work shows that in non-centrosymmetric trilayers the domain wall dynamics can be finely tuned by engineering the DMI strength, in view of efficient devices for logic and spitronics applications.Comment: 5 pages, 4 Figure

A Robot Mimicking Heart Motions: An Ex-Vivo Test Approach for Cardiac Devices

PURPOSE: The pre-clinical testing of cardiovascular implants gains increasing attention due to the complexity of novel implants and new medical device regulations. It often relies on large animal experiments that are afflicted with ethical and methodical challenges. Thus, a method for simulating physiological heart motions is desired but lacking so far. METHODS: We developed a robotic platform that allows simulating the trajectory of any point of the heart (one at a time) in six degrees of freedom. It uses heart motion trajectories acquired from cardiac magnetic resonance imaging or accelero-meter data. The rotations of the six motors are calculated based on the input trajectory. A closed-loop controller drives the platform and a graphical user interface monitors the functioning and accuracy of the robot using encoder data. RESULTS: The robotic platform can mimic physiological heart motions from large animals and humans. It offers a spherical work envelope with a radius of 29 mm, maximum acceleration of 20 m/s(2) and maximum deflection of ±19° along all axes. The absolute mean positioning error in x-, y- and z-direction is 0.21 ±0.06, 0.31 ±0.11 and 0.17 ±0.12 mm, respectively. The absolute mean orientation error around x-, y- and z-axis (roll, pitch and yaw) is 0.24 ±0.18°, 0.23 ±0.13° and 0.18 ±0.18°, respectively. CONCLUSION: The novel robotic approach allows reproducing heart motions with high accuracy and repeatability. This may benefit the device development process and allows re-using previously acquired heart motion data repeatedly, thus avoiding animal trials. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13239-021-00566-3

Moderne Public Affairs versus traditionelle Interessenvertretung? Agenturen, Unternehmen und Verbände in der politischen Kommunikation

'Die Bedingungen und Merkmale der politischen Vertretung gesellschaftlicher Interessen verändern sich: Die Zahl und Vielfalt von Akteuren nimmt zu, Einflussnahme erfolgt zielgerichtet und punktuell, die Relevanz institutionalisierter Zugänge zu Entscheidungssystemen nimmt ab und es ist eine Informalisierung wie auch Medialisierung politischer Interessenvertretung zu beobachten. Vor diesem Hintergrund will der Beitrag die Frage beantworten, wie sich Agenturen, Unternehmen und Verbände als AkteurInnen politischer Kommunikation unterscheiden. Empirische Grundlage ist eine sekundäranalytische Auswertung zweier Befragungen von Verantwortlichen für politische Interessenvertretung in der Schweiz, deren Organisationen primär Interessen aus dem Bereich Wirtschaft vertreten. Die Befunde zeigen, dass vor allem Agenturen und mit Abstrichen Unternehmen als Promotoren einer 'modernen' Public Affairs gelten können, während sich Verbände eher an 'traditionellen' Formen der politischen Interessenvertretung orientieren.' (Autorenreferat)'The representation of political interests is changing: more and more actors are involved, the diversity of interests is increasing, institutionalized structures of corporatism are in decline. Instead, strategies become more tightly and short term focused on the exertion of political influence. This comes along with an 'informalization' and 'mediatization' of interest representation. Against this background, the article is analyzing, how consultancies, business organizations and associations differ in their ways of influencing politics in economic fields. The empirical data come from two Swiss surveys. The results show that especially consultancies and to a less extent business organizations reflect changing conditions of interest representation. They can be regarded as promoters of 'modern' public affairs, whereas associations prefer 'traditional' ways of influencing political decision making.' (author's abstract)

Optical intensity interferometry lab tests in preparation of stellar diameter measurements at IACTs at GHz photon rates

Astronomical intensity interferometry enables quantitative measurements of the source geometry by measuring the photon fluxes in individual telescopes and correlating them, rather than correlating the electromagnetic waves' amplitudes. This simplifies realization of large telescope baselines and high angular resolutions. Imaging Atmospheric Cherenkov Telescopes (IACTs), intended to detect the optical emission of $\gamma$-ray induced air showers, are excellent candidates to perform intensity correlations in the optical at reasonable signal-to-noise ratios. The detected coherence time is on the scale of $10^{-12}$ to $10^{-15}$~seconds - depending on the optical bandwidth of the measurement - which challenges the detection system to work in a stable and accurate way. We developed an intensity interferometry setup applicable to IACTs, which measures the photo currents from photomultipliers and correlates them offline, and as such is designed to handle the very large photon rates provided by the telescopes. We present measurements in the lab simulating starlight using a xenon lamp and measured at different degrees of temporal and spatial coherence. Necessary calibration procedures are described with the goal of understanding the measurements quantitatively. Measured coherence times between $5\,$femtoseconds (corresponding signal-to-background ratio $5\cdot10^{-7}$) and $110\,$femtoseconds (signal-to-background ratio $10^{-5}$) are in good agreement with expectations, and so are the noise levels in the correlations, reaching down to $6 \cdot 10^{-8}$, after measurements between $30\,$minutes and $1\,$ hour

Corrigendum to: "Variations of sedimentary Fe and Mn fractions under changing lake mixing regimes, oxygenation and land surface processes during Late-glacial and Holocene times" [Sci. Total Environ. 755 (2021) 143418].

ISSN:0048-9697ISSN:1879-102

Evidence of blood stage efficacy with a virosomal malaria vaccine in a Phase IIa clinical trial

Background Previous research indicates that a combination vaccine targeting different stages of the malaria life cycle is likely to provide the most effective malaria vaccine. This trial was the first to combine two existing vaccination strategies to produce a vaccine that induces immune responses to both the pre-erythrocytic and blood stages of the P. falciparum life cycle. Methods This was a Phase I/IIa study of a new combination malaria vaccine FFM ME-TRAP+PEV3A. PEV3A includes peptides from both the pre-erythrocytic circumsporozoite protein and the blood-stage antigen AMA-1. This study was conducted at the Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, UK. The participants were healthy, malaria naïve volunteers, from Oxford. The interventions were vaccination with PEV3A alone, or PEV3A+FFM ME-TRAP. The main outcome measure was protection from malaria in a sporozoite challenge model. Other outcomes included measures of parasite specific immune responses induced by either vaccine; and safety, assessed by collection of adverse event data. Results We observed evidence of blood stage immunity in PEV3A vaccinated volunteers, but no volunteers were completely protected from malaria. PEV3A induced high antibody titres, and antibodies bound parasites in immunofluorescence assays. Moreover, we observed boosting of the vaccine-induced immune response by sporozoite challenge. Immune responses induced by FFM ME-TRAP were unexpectedly low. The vaccines were safe, with comparable side effect profiles to previous trials. Although there was no sterile protection two major observations support an effect of the vaccine-induced response on blood stage parasites: (i) Lower rates of parasite growth were observed in volunteers vaccinated with PEV3A compared to unvaccinated controls (p = 0.012), and this was reflected in the PCR results from PEV3A vaccinated volunteers. These showed early control of parasitaemia by some volunteers in this group. One volunteer, who received PEV3A alone, was diagnosed very late, on day 20 compared to an average of 11.8 days in unvaccinated controls. (ii). Morphologically abnormal parasites were present in the blood of all (n = 24) PEV3A vaccinated volunteers, and in only 2/6 controls (p = 0.001). We describe evidence of vaccine-induced blood stage efficacy for the first time in a sporozoite challenge study

Dimension of pain-related quality of life and self-reported mental health in men and women of the European Prospective Investigation into Cancer–Norfolk cohort : a population-based cross-sectional study

Acknowledgement: The authors thank Prof. Gary J Macfarlane, Head of Epidemiology Group, University of Aberdeen, for discussions and constructive comments during manuscript preparation. We also wish to thank the participants of the EPIC-Norfolk cohort, staff, co-PIs, and the funders. The EPIC-Norfolk study was supported by grants from the Cancer Research UK and Medical Research Council (UK). Funders have no role in study design and interpretation of the results. Funding Sources: The EPIC-Norfolk study was supported by grants from the Cancer Research UK (CRUK 14136) and Medical Research Council UK (MRC: G1000143). Funders have no role in study design and interpretation of the results.Peer reviewedPostprin

Energy Harvesting from the Cardiovascular System, or How to Get a Little Help from Yourself

Human energy harvesting is envisioned as a remedy to the weight, the size, and the poor energy density of primary batteries in medical implants. The first implant to have necessarily raised the idea of a biological power supply was the pacemaker in the early 1960s. So far, review articles on human energy harvesting have been rather unspecific and no tribute has been given to the early role of the pacemaker and the cardiovascular system in triggering research in the field. The purpose of the present article is to provide an up-to-date review of research efforts targeting the cardiovascular system as an alternative energy source for active medical implants. To this end, a chronological survey of the last 14 most influential publications is proposed. They include experimental and/or theoretical studies based on electromagnetic, piezoelectric, or electrostatic transducers harnessing various forms of energy, such as heart motion, pressure gradients, and blood flow. Technical feasibility does not imply clinical applicability: although most of the reported devices were shown to harvest an interesting amount of energy from a physiological environment, none of them were tested in vivo for a longer period of tim