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Publications

2024

Quantum advantage in temporally flat measurement-based quantum computation

Authors
de Oliveira, M; Barbosa, LS; Galvao, EF;

Publication
QUANTUM

Abstract
Several classes of quantum circuits have been shown to provide a quantum computational advantage under certain assumptions. The study of ever more restricted classes of quantum circuits capable of quantum advantage is motivated by possible simplifications in experimental demonstrations. In this paper we study the efficiency of measurement-based quantum computation with a completely flat temporal ordering of measurements. We propose new constructions for the deterministic computation of arbitrary Boolean functions, drawing on correlations present in multi-qubit Greenberger, Horne, and Zeilinger (GHZ) states. We characterize the necessary measurement complexity using the Clifford hierarchy, and also generally decrease the number of qubits needed with respect to previous constructions. In particular, we identify a family of Boolean functions for which deterministic evaluation using non-adaptive MBQC is possible, featuring quantum advantage in width and number of gates with respect to classical circuits.

2024

Does Technological Innovativeness Influence Users' Experiences With Virtual Reality Tourism?

Authors
Sousa, N; Jorge, F; Teixeira, MS; Losada, N; Alen, E; Guttentag, D;

Publication
INTERNATIONAL JOURNAL OF TOURISM RESEARCH

Abstract
Immersive experiences offered by virtual reality (VR) have the power to impact tourists' decision-making and on-site experiences. However, prior research has focused on explaining VR's acceptance by tourists as a function of technological capacity, rather than user characteristics, such as innovativeness. This research intends to fill the existing knowledge gap regarding the role of technological innovativeness on VR experiences. To do so, this study examines whether individuals' technological innovativeness influences their perceptions of a VR tourism experience and, in turn, their intention to recommend the experience. The study provides a VR experience to 405 tourists at a winery. The results reveal that the tourists' technological innovativeness influences their perception of enjoyment, experience quality, and satisfaction. These findings suggest that, when developing or distributing VR content, the technological innovativeness of the audience is important to consider. The findings have theoretical and practical value, with direct implications for tourism professionals and policymakers.

2024

The cool brown dwarf Gliese 229 B is a close binary

Authors
Xuan, JW; Mérand, A; Thompson, W; Zhang, Y; Lacour, S; Blakely, D; Mawet, D; Oppenheimer, R; Kammerer, J; Batygin, K; Sanghi, A; Wang, J; Ruffio, JB; Liu, MC; Knutson, H; Brandner, W; Burgasser, A; Rickman, E; Bowens-Rubin, R; Salama, M; Balmer, W; Blunt, S; Bourdarot, G; Caselli, P; Chauvin, G; Davies, R; Drescher, A; Eckart, A; Eisenhauer, F; Fabricius, M; Feuchtgruber, H; Finger, G; Schreiber, NMF; Garcia, P; Genzel, R; Gillessen, S; Grant, S; Hartl, M; Haussmann, F; Henning, T; Hinkley, S; Hönig, SF; Horrobin, M; Houllé, M; Janson, M; Kervella, P; Kral, Q; Kreidberg, L; Le Bouquin, JB; Lutz, D; Mang, F; Marleau, GD; Millour, F; More, N; Nowak, M; Ott, T; Otten, G; Paumard, T; Rabien, S; Rau, C; Ribeiro, DC; Bordoni, MS; Sauter, J; Shangguan, J; Shimizu, TT; Sykes, C; Soulain, A; Spezzano, S; Straubmeier, C; Stolker, T; Sturm, E; Subroweit, M; Tacconi, LJ; van Dishoeck, EF; Vigan, A; Widmann, F; Wieprecht, E; Winterhalder, TO; Woillez, J;

Publication
NATURE

Abstract
Owing to their similarities with giant exoplanets, brown dwarf companions of stars provide insights into the fundamental processes of planet formation and evolution. From their orbits, several brown dwarf companions are found to be more massive than theoretical predictions given their luminosities and the ages of their host stars1-3. Either the theory is incomplete or these objects are not single entities. For example, they could be two brown dwarfs each with a lower mass and intrinsic luminosity1,4. The most problematic example is Gliese 229 B (refs. 5,6), which is at least 2-6 times less luminous than model predictions given its dynamical mass of 71.4 +/- 0.6 Jupiter masses (MJup) (ref. 1). We observed Gliese 229 B with the GRAVITY interferometer and, separately, the CRIRES+ spectrograph at the Very Large Telescope. Both sets of observations independently resolve Gliese 229 B into two components, Gliese 229 Ba and Bb, settling the conflict between theory and observations. The two objects have a flux ratio of 0.47 +/- 0.03 at a wavelength of 2 mu m and masses of 38.1 +/- 1.0 and 34.4 +/- 1.5 MJup, respectively. They orbit each other every 12.1 days with a semimajor axis of 0.042 astronomical units (au). The discovery of Gliese 229 BaBb, each only a few times more massive than the most massive planets, and separated by 16 times the Earth-moon distance, raises new questions about the formation and prevalence of tight binary brown dwarfs around stars. Analysis of the cool brown dwarf Gliese 229 B suggests that it is actually a close binary of two less massive brown dwarfs, explaining its low luminosity and settling the conflict between theoretical predictions and measurements.

2024

The veterinary medicinal products market supply gap: A practical insight based on the Regulation (EU) 2019/6

Authors
Nogueira, R; Baptista, CJ; Gonçalves, L; Coelho, AC; Faustino Rocha, I; Purriños, MR; Gonzalo Orden, M; Oliveira, A;

Publication
Revista de Ciencias Agroveterinarias

Abstract
The Regulation (EU) 2019/6 establishes that the veterinary prescriptions should follow a cascade, according to their availability of the market. In sum, the veterinarian is authorized to use a medicine for human use only if there is no product available for the same or other therapeutic indication, in the same or another animal species. This study aims to analyse the application of Regulation (EU) 2019/6 in the pharmacological prescription at the Veterinary Hospital of the University of León. A total of 121 clinical cases, 89 dogs (73.55%) and 32 cats (26.45%) were included. Results revealed that 95 medicines were prescribed, 51 (53.68 %) as veterinary medicines and 44 (46.32 %) as human medicines. From the human medicines, 22 (50.00%) did not have a veterinary alternative in the market; four (9.00%) presented a veterinary medicine in the appropriate formulation for the species; 10 (23.00%) had no alternative in the desired formulation; and 8 (18.00%) had no alternatives for the target species. This study suggested that the cascade was not strictly followed, and several reasons may justify it, such as the lack of veterinary products, different formulations, and differences in costs. An effective, safe and sustainable use of the therapeutic option available can only be accomplished with a rational use of the prescription cascade and a correct use of the Regulation (EU) 2019/6. © 2024 State University of Santa Catarina. All rights reserved.

2024

Weaving Agility in Safety-Critical Software Development for Aerospace: From Concerns to Opportunities

Authors
Ribeiro, JEF; Silva, JG; Aguiar, A;

Publication
IEEE ACCESS

Abstract
Domain-specific standards and documents heavily regulate safety-critical systems. One example is the DO-178C standard for aerospace, which guides organizations to achieve system safety and evidence for their certification. Under such regulated contexts, most organizations use traditional development processes, in contrast to the massive adoption of Agile in the software industry. Among other benefits, Agile methods promise faster delivery and better flexibility to address customer needs. Adopting Agile methods and practices are possible in aerospace because the DO-178C standard does not prescribe concrete software development methods. In spite of that, Agile development is not used in DO-178C contexts. To help change that, our research aims to understand whether and how organizations engineering safety-critical software systems for aerospace may benefit from Agile methods and practices. We analyzed the DO-178C standard and confirm that it is compatible with Agile methods. Then, we present a systematic literature mapping of adopting Agile in software development for aerospace, where we identified significant concerns, recurrent issues, and several challenges. Some real industry aerospace projects provided us with important data and the perspective of domain experts about the pros and cons of Agile methods in this context. We conclude by proposing an agenda of research opportunities to improve safety-critical software development towards agility that we consider worthy of further research, application and confirmation in wider contexts.

2024

Tabulation with Zippers

Authors
Viera, M; Pardo, A; Saraiva, J;

Publication
FUNCTIONAL AND LOGIC PROGRAMMING, FLOPS 2024

Abstract
Tabulation is a well-known technique for improving the efficiency of recursive functions with redundant function calls. A key point in the application of this technique is to identify a suitable representation for the table. In this paper, we propose the use of zippers as tables in the tabulation process. Our approach relies on a generic function zipWithZipper, that makes strong use of lazy evaluation to traverse two zippers in a circular manner. The technique turns out to be particularly efficient when the arguments to recursive calls are closely situated within the function domain. For example, in the case of natural numbers this means function calls on fairly contiguous values. Likewise, when dealing with tree structures, it means functions calls on immediate sub-trees and parent nodes. This results in a concise and efficient zipper-based embedding of attribute grammars.

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