The MARES AUV, a Modular Autonomous Robot for Environment Sampling

In this paper, we discuss the design aspects and the development of the MARES AUV, a 1.5m long vehicle, weighting 32kg, designed and built at the University of Porto, Portugal. This vehicle is highly maneuverable, with the ability to move in the vertical plane, controlling pitch and vertical velocity; forward velocity can also be determined, anywhere between 0 and 2 m/s. MARES can easily integrate any new payload within reason, finding applications in a wide range or areas, such as pollution monitoring, scientific data collection, sonar mapping, underwater video or mine countermeasures

Development and implementation of a low-cost LBL navigation system for an AUV

A reliable navigation system is a key factor for the success of an operational mission with an AUV in a real scenario. In this paper, we address the main issues involved in the implementation of a long baseline (LBL) navigation system for a REMUS AUV. This system replaces both the original hardware and software of the vehicle with a simpler, faster, less expensive and more precise system, based on a Kalman filter. We also discuss the influence of transponder location in the overall performance of the LBL navigation, and present results obtained with this new system in operational missions

Scalar Field Dark Matter: behavior around black holes

We present the numerical evolution of a massive test scalar fields around a Schwarzschild space-time. We proceed by using hyperboloidal slices that approach future null infinity, which is the boundary of scalar fields, and also demand the slices to penetrate the event horizon of the black hole. This approach allows the scalar field to be accreted by the black hole and to escape toward future null infinity. We track the evolution of the energy density of the scalar field, which determines the rate at which the scalar field is being diluted. We find polynomial decay of the energy density of the scalar field, and use it to estimate the rate of dilution of the field in time. Our findings imply that the energy density of the scalar field decreases even five orders of magnitude in time scales smaller than a year. This implies that if a supermassive black hole is the Schwarzschild solution, then scalar field dark matter would be diluted extremely fastComment: 15 pages, 21 eps figures. Appendix added, accepted for publication in JCA

As relações entre percepção de ameaça, ansiedade, raiva e agressividade no desporto: um estudo comparativo em modalidades de contacto

Com o presente estudo pretendeu-se compreender e analisar, em modalidades desportivas com diferentes níveis de contacto físico, as relações entre a percepção de ameaça subjacente à experiência de stress e duas emoções “tonalizadas” negativamente: a ansiedade e a raiva. Os 121 atletas de ambos os sexos que participaram na investigação, com idades compreendidas entre os 14 e os 32 anos distribuíam-se por três modalidades distintas: auto-defesa (N=35), “kickboxing” (N=39) e futebol (N=47). Foram administradas as seguintes medidas psicológicas (versões traduzidas e/ou adaptadas): a) Escala de Avaliação Cognitiva da Competição Desportiva – Percepção de Ameaça (Cruz, 1996); b) Escala de Agressividade e Raiva Competitiva (Maxwell & Moores, 2007; Cruz, 2007); e c) Escala de Ansiedade Competitiva – 2 (Smith et al., 2006; Cruz & Gomes, 2007). Os resultados preliminares sugerem as boas características psicométricas dos instrumentos utilizados. Serão ainda apresentados dados correlacionais em função do sexo e modalidade e algumas implicações práticas para o estudo dos comportamentos agressivos no desporto

Phase-only shaped beam transmit-array

A new analytical formulation is presented in this paper to obtain the phase correction function for planar transmitarrays, to produce a prescribed amplitude template. This phaseonly design enables using high transmission unit cells to favor maximum gain. Here, a transmit-array transforms the known power radiation pattern of the primary source into a desired output power pattern. As a proof of concept, two different output power radiation patterns are presented, namely, a sec2 with a roll-off at 45º and a flat-top with 20º of roll-off, at the 30 GHz Ka-band. The transmit-array aperture is 180 mm × 180 mm, with 60 mm focal length. It is illuminated by a 10.8 dBi feed radiation pattern, with circular polarizationinfo:eu-repo/semantics/acceptedVersio

Synthesis of shaped-beam radiation patterns at millimeter-waves using transmit arrays

Transmit arrays have been mostly used for beam collimation applications, either with fixed or scanning beam capability. But transmit arrays can also be used to synthesize power radiation patterns complying with power pattern templates. A new analytical formulation is presented here to obtain a phase-only correction function corresponding to a given power template. The transmit-array transforms the known power radiation pattern of the primary source into a desired output power pattern. The proposed formulation, specialized for axial-symmetric structures, is based on geometrical optics and provides the solution directly from the evaluation of two closed-form first-order differential equations. As a proof of concept, a sec 2 with a roll-off at 45° is defined as the target power pattern, at the 30 GHz Ka-band. A 10.8 dBi radiation pattern with the circular polarization is used to illuminate a 180 mm ×180 mm transmit array with 60 mm focal distance. Previously designed 3.35 mm thick phase-delay unit cells are used as an example to implement the calculated phase distribution over the transmit-array aperture. The measured antenna radiation pattern matches quite well the template, with a steep fall of the radiation at the roll-off angle and low cross-polarization. This validates the concept, the formulation, and the fabricated prototype.info:eu-repo/semantics/acceptedVersio

Generalized Lymphadenopathy as the First Manifestation of Systemic Lupus Erythematosus

Lymphadenopathy (LAP) is a common but nonspecific feature of many diseases, representing a vast spectrum of etiologies such as infectious or inflammatory diseases, malignancies, and drugs. In systemic lupus erythematosus (SLE), it can be the first manifestation. We present the case of a 20-year-old female with a history of fever, night sweats, anorexia, and asthenia for five months. She also had diffuse generalized LAP. Although malignant etiologies were our major concern, an extensive workup for malignancy and infections was unrevealing. However, an autoimmune workup led to the diagnosis of SLE. This case shows that SLE can present as generalized LAP with constitutional symptoms, and hence it should be considered in the differential diagnosis.info:eu-repo/semantics/publishedVersio

Physical vapor deposition technology in personal protective equipment production: improved antibacterial and hydrophobic character of textiles

Personal protective equipment (PPE) has been adapted as biological threats have emerged, such as increasingly drug-resistant bacteria and the emergence of new viruses such as COVID-19. PPE must be increasingly resilient to prevent the proliferation of pathogens, but using sustainable raw materials and environmentally friendly technologies. The aim of this study is to show a new way of modifying the surface of various types of fabrics to enable their efficient use as PPE. The Ag/DLC coating was successfully deposited by sputtering onto several types of textiles using different chemical compositions of Ag/DLC (0, 8, 10, and 12Ag). As a crucial parameter, wettability was evaluated, showing that silver addition increases the hydrophobicity character of the coated fabrics, namely in cotton, changing from hydrophilic to hydrophobic. Antibacterial activity and cytotoxicity were evaluated on all coatings, revealing that they are efficient in eliminating the spread of bacteria (Staphylococcus aureus and Klebsiella pneumoniae) and pose no risk to the human body. The results presented here are promising in protecting healthcare workers, with the next steps being to study the efficiency of these coatings against viruses. In addition, this study reveals an opportunity to use sustainable fabrics, such as cotton, with high efficiency in protection against pathogens, instead of synthetic fiber textiles.info:eu-repo/semantics/publishedVersio

Características psicométricas de uma versão portuguesa do "Competitive State Anxiety Inventory - 2" (CSAI-2) : dados preliminares relativos à sua validade e estrutura factorial

Para analisar as características psicométricas do "Competitive State Anxiety Inventory-2" (medida multidimensional do estado de ansiedade competitiva, com 27 itens), uma versão portuguesa foi administrada a 157 atletas de 5 modalidades (antes e depois da competição). Os dados obtidos sugerem uma estrutura de 3 factores idêntica à original, mas com a redução para 22 itens. Foram obtidos bons índices de fidelidade desta versão (.87 ansiedade cognitiva; .81 ansiedade somática; e .89 auto-confiança). Sugere-se a validade desta versão no estudo da relação ansiedade-rendimento desportivo