Statistical characterization of polychromatic absolute and differential squared visibilities obtained from AMBER/VLTI instrument

In optical interferometry, the visibility squared modulus are generally assumed to follow a Gaussian distribution and to be independent of each other. A quantitative analysis of the relevance of such assumptions is important to help improving the exploitation of existing and upcoming multi-wavelength interferometric instruments. Analyze the statistical behaviour of both the absolute and the colour-differential squared visibilities: distribution laws, correlations and cross-correlations between different baselines. We use observations of stellar calibrators obtained with AMBER instrument on VLTI in different instrumental and observing configurations, from which we extract the frame-by-frame transfer function. Statistical hypotheses tests and diagnostics are then systematically applied. For both absolute and differential squared visibilities and under all instrumental and observing conditions, we find a better fit for the Student distribution than for the Gaussian, log-normal and Cauchy distributions. We find and analyze clear correlation effects caused by atmospheric perturbations. The differential squared visibilities allow to keep a larger fraction of data with respect to selected absolute squared visibilities and thus benefit from reduced temporal dispersion, while their distribution is more clearly characterized. The frame selection based on the criterion of a fixed SNR value might result in either a biased sample of frames or in a too severe selection.Comment: A&A, 13 pages and 9 figure

Constant-pressure sound waves in non-Hermitian disordered media

When waves impinge on a disordered material they are back-scattered and form a highly complex interference pattern. Suppressing any such distortions in the free propagation of a wave is a challenging task with many applications in a number of different disciplines. In a recent theoretical proposal, it was pointed out that both perfect transmission through disorder as well as a complete suppression of any variation in a wave intensity can be achieved by adding a continuous gain-loss distribution to the disorder. Here we show that this abstract concept can be implemented in a realistic acoustic system. Our prototype consists of an acoustic waveguide containing several inclusions that scatter the incoming wave in a passive configuration and provide the gain or loss when being actively controlled. Our measurements on this non-Hermitian acoustic metamaterial demonstrate unambiguously the creation of a reflectionless scattering wave state that features a unique form of discrete constant-amplitude pressure waves. In addition to demonstrating that gain-loss additions can turn localised systems into transparent ones, we expect our proof-of-principle demonstration to trigger interesting new developments not only in sound engineering, but also in other related fields such as in non-Hermitian photonics

Topology of Fracture Networks

We propose a mapping from fracture systems consisting of intersecting fracture sheets in three dimensions to an abstract network consisting of nodes and links. This makes it possible to analyze fracture systems with the methods developed within modern network theory. We test the mapping for two-dimensional geological fracture outcrops and find that the equivalent networks are small-world and dissasortative. By anlayzing the Discrete Fracture Network model, which is used to generate artifical fracture networks, we also find small world networks. However, the networks turn out to be assortative.Comment: 5 pages, 6 figure

A Robust Data-Driven Model for Flapping Aerodynamics under different hovering kinematics

Flapping Wing Micro Air Vehicles (FWMAV) are highly manoeuvrable, bio-inspired drones that can assist in surveys and rescue missions. Flapping wings generate various unsteady lift enhancement mechanisms challenging the derivation of reduced models to predict instantaneous aerodynamic performance. In this work, we propose a robust CFD data-driven, quasi-steady (QS) Reduced Order Model (ROM) to predict the lift and drag coefficients within a flapping cycle. The model is derived for a rigid ellipsoid wing with different parameterized kinematics in hovering conditions. The proposed ROM is built via a two-stage regression. The first stage, defined as `in-cycle' (IC), computes the parameters of a regression linking the aerodynamic coefficients to the instantaneous wing state. The second stage, `out-of-cycle' (OOC), links the IC weights to the flapping features that define the flapping motion. The training and test dataset were generated via high-fidelity simulations using the overset method, spanning a wide range of Reynolds numbers and flapping kinematics. The two-stage regressor combines Ridge regression and Gaussian Process (GP) regression to provide estimates of the model uncertainties. The proposed ROM shows accurate aerodynamic predictions for widely varying kinematics. The model performs best for smooth kinematics that generate a stable Leading Edge Vortex (LEV). Remarkably accurate predictions are also observed in dynamic scenarios where the LEV is partially shed, the non-circulatory forces are considerable, and the wing encounters its own wake.Comment: submitted to Physics of Fluid

Development of a distance learning platform based on a network of connected labs to study the energy performance of buildings systems

peer reviewedThe energy performance of building systems for heating, cooling, lighting and ventilation is a driving factor to reduce global CO2 emissions and mitigate climate change. Five Universities located in Belgium, France, Germany and Luxembourg have joined to connect their thermal laboratories to provide complementary research and teaching capabilities to contribute to more sustainability in the building sector. Within the project RCC|KN, Network of Climatic Chambers (“Réseau de Chambres Climatiques | Klimalabor Netzwerk”) which started in 2018, the laboratories and their equipment were connected through a remote connection on a digital platform [1]. The platform delivers real time data (temperature, pressure, humidity, flow rates, controls from the equipment, thermal comfort values) from the laboratories and it offers the opportunity to perform remote experiments between the connected labs. Furthermore, the platform can be connected to a simulation tool (TRNSYS) to extend the applicability of the experiments via emulation [2]. This paper aims to present the next step of the RCC/KN project which is the development of a multistakeholder distance learning platform for university students and practitioners. It will be based on the RCC/KN platform and allows the remote testing and distance learning in the field of thermal systems and building environment. In addition to the complementarity of sensors and equipment in the different labs, the Covid pandemic further increases the need for such a joint effort to offer cross-institutional collaboration in a digital format. The platform will encourage the interaction of students as they can decide over possible solutions, for example in terms of choosing the right system to maintain thermal comfort, they can experience the inertia of different heat emission systems and the actual energy demand needed to achieve the required conditions. It will enhance the students’ ability to set up an experiment with the given systems, monitoring the output during the experiment, working with the gathered data and analysing the results. Through the digital lab experiments they will improve their understanding of how to operate buildings in an energy efficient way and hence, later on in their career, they are able to contribute to a reduction of greenhouse gas emissions in the building sector.Réseau de Chambres Climatiques | Klimalabor Netzwerk RCC|K

Hardware-in-the-Loop Platform for Performance Evaluation of Energy Production, Storage and Distribution Systems for Buildings

peer reviewedThe current study carried out within the framework of the PEPSE (Semi-virtual Platform for performance Evaluation of Energy Production, Storage and distribution systems for buildings) project aims at designing, developing and setting up the infrastructure and the equipment of a laboratory for evaluating the energy performance of heating and cooling production, storage and distribution systems in buildings. The platform is semi-virtual, i.e. energy sources and loads can be real or simulated. The virtual environment (which is a numerical program for simulating energy sources and loads) controls the inlet conditions and the operation of tested device by means of one or several satellite units (i.e. physical interfaces) located on the distribution and return lines of the hydraulic/air-flow loops. The equipment outlet conditions are also sent back towards the simulation program by these interfaces. The latter are supplied with hot and cold water by two energy production and distribution systems. The maximum power of devices to be tested could be up to 200 kW (heating or cooling). This capacity allows the laboratory to test a relatively wide range of devices from the heating or cooling appliances of a single-family house to the energy equipment/system of multi-family residential building or the equipment for district heating system, etc.PEPSE (Poste d’Essai « semi-virtuel » pour le test de systèmes de Production, de Stockage et de distribution d’Energie

Organelle trafficking of chimeric ribozymes and genetic manipulation of mitochondria

With the expansion of the RNA world, antisense strategies have become widespread to manipulate nuclear gene expression but organelle genetic systems have remained aside. The present work opens the field to mitochondria. We demonstrate that customized RNAs expressed from a nuclear transgene and driven by a transfer RNA-like (tRNA-like) moiety are taken up by mitochondria in plant cells. The process appears to follow the natural tRNA import specificity, suggesting that translocation indeed occurs through the regular tRNA uptake pathway. Upon validation of the strategy with a reporter sequence, we developed a chimeric catalytic RNA composed of a specially designed trans-cleaving hammerhead ribozyme and a tRNA mimic. Organelle import of the chimeric ribozyme and specific target cleavage within mitochondria were demonstrated in transgenic tobacco cell cultures and Arabidopsis thaliana plants, providing the first directed knockdown of a mitochondrial RNA in a multicellular eukaryote. Further observations point to mitochondrial messenger RNA control mechanisms related to the plant developmental stage and culture conditions. Transformation of mitochondria is only accessible in yeast and in the unicellular alga Chlamydomonas. Based on the widespread tRNA import pathway, our data thus make a breakthrough for direct investigation and manipulation of mitochondrial genetics

Nivolumab plus ipilimumab versus chemotherapy as first-line treatment in advanced non-small-cell lung cancer with high tumour mutational burden: Patient-reported outcomes results from the randomised, open-label, phase III CheckMate 227 trial

BACKGROUND: In the phase III CheckMate 227 study, first-line nivolumab + ipilimumab significantly prolonged progression-free survival (co-primary end-point) versus chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) and high tumour mutational burden (TMB; ≥10 mutations/megabase). AIM: To evaluate patient-reported outcomes (PROs) in this population. METHODS: Disease-related symptoms and general health status were assessed using the validated PRO questionnaires Lung Cancer Symptom Scale (LCSS) and EQ-5D, respectively. LCSS average symptom burden index (ASBI) and three-item global index (3-IGI) and EQ-5D visual analogue scale (VAS) and utility index (UI) scores and changes from baseline were analysed descriptively. Longitudinal changes were assessed by mixed-effect model repeated measures (MMRMs) and time to first deterioration/improvement analyses. RESULTS: In the high TMB population, PRO questionnaire completion rates were ∼90% at baseline and \u3e80% for most on-treatment assessments. During treatment, mean changes from baseline with nivolumab + ipilimumab showed early, clinically meaningful improvements in LCSS ASBI/3-IGI and EQ-5D VAS/UI; with chemotherapy, symptoms and health-related quality of life remained stable (LCSS ASBI/3-IGI, EQ-5D UI) or improved following induction (EQ-5D VAS). MMRM-assessed changes in symptom burden were improved with nivolumab + ipilimumab versus chemotherapy. Symptom deterioration by week 12 was lower with nivolumab + ipilimumab versus chemotherapy (22.3% versus 35.0%; absolute risk reduction: 12.7% [95% confidence interval 2.4-22.5]), irrespective of discontinuation. Time to first deterioration was delayed with nivolumab + ipilimumab versus chemotherapy across LCSS and EQ-5D summary measures. CONCLUSION: First-line nivolumab + ipilimumab demonstrated early, sustained improvements in PROs versus chemotherapy in patients with advanced NSCLC and high TMB. CLINICAL TRIAL REGISTRATION: NCT02477826

Nivolumab plus ipilimumab versus chemotherapy as first-line treatment in advanced non-small-cell lung cancer with high tumour mutational burden: Patient-reported outcomes results from the randomised, open-label, phase III CheckMate 227 trial

BACKGROUND: In the phase III CheckMate 227 study, first-line nivolumab + ipilimumab significantly prolonged progression-free survival (co-primary end-point) versus chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) and high tumour mutational burden (TMB; ≥10 mutations/megabase). AIM: To evaluate patient-reported outcomes (PROs) in this population. METHODS: Disease-related symptoms and general health status were assessed using the validated PRO questionnaires Lung Cancer Symptom Scale (LCSS) and EQ-5D, respectively. LCSS average symptom burden index (ASBI) and three-item global index (3-IGI) and EQ-5D visual analogue scale (VAS) and utility index (UI) scores and changes from baseline were analysed descriptively. Longitudinal changes were assessed by mixed-effect model repeated measures (MMRMs) and time to first deterioration/improvement analyses. RESULTS: In the high TMB population, PRO questionnaire completion rates were ∼90% at baseline and \u3e80% for most on-treatment assessments. During treatment, mean changes from baseline with nivolumab + ipilimumab showed early, clinically meaningful improvements in LCSS ASBI/3-IGI and EQ-5D VAS/UI; with chemotherapy, symptoms and health-related quality of life remained stable (LCSS ASBI/3-IGI, EQ-5D UI) or improved following induction (EQ-5D VAS). MMRM-assessed changes in symptom burden were improved with nivolumab + ipilimumab versus chemotherapy. Symptom deterioration by week 12 was lower with nivolumab + ipilimumab versus chemotherapy (22.3% versus 35.0%; absolute risk reduction: 12.7% [95% confidence interval 2.4-22.5]), irrespective of discontinuation. Time to first deterioration was delayed with nivolumab + ipilimumab versus chemotherapy across LCSS and EQ-5D summary measures. CONCLUSION: First-line nivolumab + ipilimumab demonstrated early, sustained improvements in PROs versus chemotherapy in patients with advanced NSCLC and high TMB. CLINICAL TRIAL REGISTRATION: NCT02477826