2019
Authors
Oliveira L.M.C.; Tuchin V.V.;
Publication
Springerbriefs in Physics
Abstract
Imaging methods are a powerful tool for diagnostic purposes. In this chapter, the most important light-imaging methods, their advantages, and drawbacks are described. The advantages of radiation-free light-based imaging methods relative to traditional radiation methods, such as X-ray, magnetic resonance, or positron emission imaging, are indicated, and the recent advances to improve probing depth, contrast, and resolution in thick tissues are demonstrated. Some historical aspects and recent improvements in light-imaging methods, such as optical coherence tomography, speckle-imaging, second harmonic generation, or light-sheet microscopies, are presented. Due to the recent combination of optical immersion clearing with light-based imaging methods, several studies have been reported, where high-quality images and 3D reconstruction have been obtained for various tissues, providing an alternative to traditional histology or histopathology methods. The purpose of optical clearing is to reduce light scattering, but tissue clearing is obtained through three mechanisms: tissue dehydration, refractive index matching, and protein dissociation. This last mechanism leads to a reduction in the intensity of protein fluorescence, which can be a disadvantage in fluorescence imaging methods. The selection of certain clearing protocols that minimizes or eliminates protein dissociation has been made by some researchers, and a review of such literature is made in the various sections of this chapter.
2019
Authors
Amorim, A; Yazici, S; Berger, JP; Brandner, W; Clenet, Y; du Foresto, VC; de Zeeuw, PT; Dexter, J; Duvert, G; Ebert, M; Eckart, A; Eisenhauer, F; Schreiber, NMF; Garcia, P; Gao, F; Gendron, E; Genzel, R; Gillessen, S; Habibi, M; Haubois, X; Henning, T; Hippler, S; Horrobin, M; Hubert, Z; Rosales, AJ; Jocou, L; Kervella, P; Lacour, S; Lapeyrere, V; Le Bouquin, JB; Lena, P; Ott, T; Paumard, T; Perraut, K; Perrin, G; Pfuhl, O; Rabien, S; Rodriguez Coira, G; Rousset, G; Scheithauer, S; Sternberg, A; Straub, O; Straubmeier, C; Sturm, E; Tacconi, LJ; Vincent, F; von Fellenberg, S; Waisberg, I; Widmann, F; Wieprecht, E; Bauboeck, M; Wiezorrek, E;
Publication
PHYSICAL REVIEW LETTERS
Abstract
During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of vertical bar beta(He) - beta(H)vertical bar = (2.4 +/- 5.1) x 10(-2). The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor of 10 larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.
2019
Authors
Martins, MS; Faria, CL; Matos, T; Goncalves, LM; Silva, A; Jesus, SM; Cruz, N;
Publication
OCEANS 2019 - Marseille, OCEANS Marseille 2019
Abstract
The lack of penetration of light and electromagnetic radiation beyond a few meters in the ocean makes acoustics the technique of choice for data transmission, target detection and ocean sensing in general. Acoustic transducers are typically based on piezoelectric materials due to the good response at high frequencies. Depending on the application it can be built using ceramics, polymers and composite materials. In the hydrostatic mode PZT ceramics hydrophones have low performance due to the low hydrostatic piezoelectric stress value. On the other hand, PVDF have shown relatively high hydrostatic mode response. This work presents the development of a PVDF hydrophone for deep sea applications. The hydrophone was subjected to a pressure test up to 25 MPa to evaluate the response variation under high hydrostatic pressure. The results show an increase up to 6 dB sensitivity under 15 MPa pressure.
2019
Authors
Guedes, AL; Guedes, FL; Chagas, WdS; Schlemmer, E;
Publication
Digital games and learning
Abstract
2019
Authors
Figueira, A; Guimaraes, N; Pinto, J;
Publication
CENTERIS2019--INTERNATIONAL CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS/PROJMAN2019--INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT/HCIST2019--INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES
Abstract
The rise of online social networks has reshaped the way information is published and spread. Users can now post in an effortless way and in any location, making this medium ideal for searching breaking news and journalistic relevant content. However, due to the overwhelming number of posts published every second, such content is hard to trace. Thus, it is important to develop methods able to detect and analyze whether a certain text contains journalistic relevant information. Furthermore, it is also important that this detection system can provide additional information towards a better comprehension of the prediction made. In this work, we overview our system, based on an ensemble classifier that is able to predict if a certain post is relevant from a journalistic perspective which outperforms the previous relevant systems in their original datasets. In addition, we describe REMINDS: a web platform built on top of our relevance system that is able to provide users with the visualization of the system's features as well as additional information on the text, ultimately leading to a better comprehension of the system's prediction capabilities. (C) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the CENTERIS -International Conference on ENTERprise Information Systems / ProjMAN - International Conference on Project MANagement / HCist - International Conference on Health and Social Care Information Systems and Technologies.
2019
Authors
Pinto, AS; Davies, MEP;
Publication
CMMR
Abstract
We explore the task of computational beat tracking for musical audio signals from the perspective of putting an end-user directly in the processing loop. Unlike existing “semi-automatic” approaches for beat tracking, where users may select from among several possible outputs to determine the one that best suits their aims, in our approach we examine how high-level user input could guide the manner in which the analysis is performed. More specifically, we focus on the perceptual difficulty of tapping the beat, which has previously been associated with the musical properties of expressive timing and slow tempo. Since musical examples with these properties have been shown to be poorly addressed even by state of the art approaches to beat tracking, we re-parameterise an existing deep learning based approach to enable it to more reliably track highly expressive music. In a small-scale listening experiment we highlight two principal trends: i) that users are able to consistently disambiguate musical examples which are easy to tap to and those which are not; and in turn ii) that users preferred the beat tracking output of an expressive-parameterised system to the default parameterisation for highly expressive musical excerpts.
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