Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe

Electroweak production of two jets in association with a Z boson in proton-proton collisions root s =13 TeV

A measurement of the electroweak (EW) production of two jets in association with a Z boson in proton-proton collisions at root s = 13 TeV is presented, based on data recorded in 2016 by the CMS experiment at the LHC corresponding to an integrated luminosity of 35.9 fb(-1). The measurement is performed in the lljj final state with l including electrons and muons, and the jets j corresponding to the quarks produced in the hard interaction. The measured cross section in a kinematic region defined by invariant masses m(ll) > 50 GeV, m(jj) > 120 GeV, and transverse momenta P-Tj > 25 GeV is sigma(EW) (lljj) = 534 +/- 20 (stat) fb (syst) fb, in agreement with leading-order standard model predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. No evidence is found and limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.6 <cwww/Lambda(2) <2.6 TeV-2 and -8.4 <cw/Lambda(2) <10.1 TeV-2. The additional jet activity of events in a signal-enriched region is also studied, and the measurements are in agreement with predictions.Peer reviewe

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

IBE-BIV Enquête 2017: Eindrapport

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Development of an image-based gloss measurement instrument

This paper reports on the development of a measurement instrument to perform gloss measurements using an image-based detector. The image-based gloss meter was built according to the specifications of the optical layout of a specular gloss meter in a 60° measurement geometry, as described in ASTM D523-14. The photodiode detector was thereby substituted with a CMOS detector. The optical layout of the system was designed and validated by the use of ray tracing software. A series of 16 matte to high-gloss test samples, with nominal gloss values ranging between 3 and 90 gloss units, was used to compare specular gloss measurements obtained with the developed instrument and a commercial specular gloss meter. An average and maximum deviation of only 1.2 and 2.7 gloss units, respectively, was obtained, confirming the suitability of the system to perform standard specular gloss measurements. The potential benefits of the image-based approach were then studied. By way of example, the optical characterization of orange peel and contrast gloss by the use of the system was discussed, corroborating the fact that the proposed instrument offers important opportunities for a more global characterization of the total gloss impression.status: Published onlin

Estimation of the suitability of a deuterium light source - monochromator system for investigation of photochemical reactions

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Verlichting en led, hoe dicht bij ons bed?

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Estimation of the suitability of a xenon light source - UV interference filter system for investigation of photochemical reactions

Feasability study requested by the Process Engineering for Sustainable Systems Section Unit of CIT, KU Leuvennrpages: 4status: publishe

New Methods and Models Improving the Prediction of Visual Gloss Perception (Nieuwe methodes en modellen ter bevordering van de voorspelling van visuele glanswaarneming)

Gloss is generally considered as an appearance attribute related to the directionally selective reflectance properties of the front surface, with a preference toward the specular reflection direction. Together with the colour and the texture, the aspect of gloss is of particular importance in several industrial applications for which the final appearance of the object determines the quality impression (automobile, paint, steel, etc.). However, quality control is generally restricted to a visual inspection of the end product by one or several employees, appointed to this task because of their many years' experience in the product development process. Besides a visual inspection, surface gloss is often quantified instrumentally by use of a specular glossmeter. This commercially available device quantifies gloss from the degree of specular reflection, measured in one to three measurement geometries, and allows for a differentiation between surfaces of similar appearance. Nowadays, more sophisticated instruments are also being introduced to analyze surface nonuniformities related to gloss, such as orange peel.The agreement between human visual gloss impression and instrumental gloss quantification by means of a glossmeter is rather disappointing. This is due to the fact that besides the amount of specular reflection, many other visual criteria may be used to assess the glossiness of a surface: the distinctness of the reflected image, the contrast between the reflected image and the surrounding surface colour, etc. These criteria are not only influenced by the intrinsic surface properties of the material, but also by the properties of the illumination and the viewing conditions of the observer.The principal aim of this doctoral research is to investigate if alternative optical measurement methods and models could be formulated, which allow for a better description of the reflection properties of a surface and for a better prediction of human visual gloss perception, respectively.The most universal method to describe the scattering properties of a material is through the bidirectional scatter distribution function (BSDF). This function describes the reflection and transmission properties for any angle of illumination or viewing, thereby offering a complete characterization of the spectral and angular optical characteristics of the surface. Many BSDF measuring methods and instruments have been developed with a specific application in mind, restricting the general applicability. As a first part of this doctoral thesis, a universal goniometric measuring instrument which allows for an absolute determination of the spectral BSDF is presented.The advent and application of photorealistic digital image representations when studying various aspects of visual appearance has recently led to important insights into the understanding of surface gloss perception. In the second part of this thesis, the question of gloss quantification in agreement with visual gloss perception is addressed, taking into account a number of recentlydemonstrated influences.Three studies are described, in the course of which visual experiments were performed in a specially designed light booth to demonstrate, among other things, the influence of the illumination geometry on gloss perception and the multidimensionality of gloss perception. In each study, test results are related to BSDF and gloss measurements, and to luminance measurements performed in the adopted conditions of illumination and viewing. In this way, the shortcomings of the specular glossmeter are revealed, and the advantages and possibilities of alternative measuring techniques are discussed. In addition, several statistical and analytical techniques are used to demonstrate the complex way in which the human visual system incorporates and distinguishes between various cues to derive a consistent impression of surface gloss. Indeed, visual gloss impression seems not only to be influenced by a huge amount of available cues; observers seem also to weigh the available cues differently.It is clear that the results presented in this thesis, deduced from visual experiments with real samples observed in a real lit environment, do not elucidate every issue in the field of gloss measurement and gloss perception. Yet, they are complementary to recent research results from digital imagery studies, and provide important new insights and suggestions for future research.nrpages: 140status: publishe