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- 10 kVp rule – An anthropomorphic pelvis phantom imaging study using a CR system: impact on image quality and effective dose using AEC and manual modePublication . Lança, Luís; Franco, Loris; Ahmed, Abdulfatah; Harderwijk, Marloes; Narti, Chloe; Nasir, Sadeeda; Ndlovu, Junior; Oliveira, Miguel; Santiago, Ana Rita; Hogg, PeterPurpose - This study aims to investigate the influence of tube potential (kVp) variation in relation to perceptual image quality and effective dose (E) for pelvis using automatic exposure control (AEC) and non-AEC in a Computed Radiography (CR) system. Methods and materials - To determine the effects of using AEC and non-AEC by applying the 10 kVp rule in two experiments using an anthropomorphic pelvis phantom. Images were acquired using 10 kVp increments (60–120 kVp) for both experiments. The first experiment, based on seven AEC combinations, produced 49 images. The mean mAs from each kVp increment were used as a baseline for the second experiment producing 35 images. A total of 84 images were produced and a panel of 5 experienced observers participated for the image scoring using the two alternative forced choice (2AFC) visual grading software. PCXMC software was used to estimate E. Results - A decrease in perceptual image quality as the kVp increases was observed both in non-AEC and AEC experiments, however no significant statistical differences (p > 0.05) were found. Image quality scores from all observers at 10 kVp increments for all mAs values using non-AEC mode demonstrates a better score up to 90 kVp. E results show a statistically significant decrease (p = 0.000) on the 75th quartile from 0.37 mSv at 60 kVp to 0.13 mSv at 120 kVp when applying the 10 kVp rule in non-AEC mode. Conclusion - Using the 10 kVp rule, no significant reduction in perceptual image quality is observed when increasing kVp whilst a marked and significant E reduction is observed.
- 1D Copper(II)-aroylhydrazone coordination polymers: magnetic properties and microwave assisted oxidation of a secondary alcoholPublication . Sutradhar, Manas; Alegria, Elisabete; Roy Barman, Tannistha; Guedes Da Silva, M. Fátima C.; Liu, Cai-Ming; Pombeiro, ArmandoThe 1D Cu(II) coordination polymers [Cu-3(L-1)(NO3)(4)(H2O)(2)](n) (1) and [Cu-2(H2L2)(NO3)(H2O)(2)](n)(NO3)(n) (2) have been synthesized using the aroylhyrazone Schiff bases N'(1),N'(2)-bis(pyridin-2-ylmethylene)oxalohydrazide (H2L1) and N'(1),N'(3)-bis(2-hydroxybenzylidene)malonohydrazide (H4L2), respectively. They have been characterized by elemental analysis, infrared (IR) spectroscopy, UV-Vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), single crystal X-ray diffraction and variable temperature magnetic susceptibility measurements (for 2). The ligand (L-1)(2-) coordinates in the iminol form in 1, whereas the amide coordination is observed for (H2L2)(2-) in 2. Either the ligand bridge or the nitrate bridge in 2 mediates weak antiferromagnetic coupling. The catalytic performance of 1 and 2 has been investigated toward the solvent-free microwave-assisted oxidation of a secondary alcohol (1-phenylethanol used as model substrate). At 120 degrees C and in the presence of the nitroxyl radical 2,2,6,6-tetramethylpiperydil-1-oxyl (TEMPO), the complete conversion of 1-phenylethanol into acetophenone occurs with TOFs up to 1,200 h(-1).
- 1D Zn(II) coordination polymer of arylhydrazone of 5,5-dimethylcyclohexane-1,3-dione as a pre-catalyst for the Henry reactionPublication . Martins, Nuno M. R.; Mahmudov, Kamran T.; Silva, M. Fátima C. Guedes; Martins, Luisa; Guseinov, Firudin I.; Pombeiro, Armando J. L.Reaction of a new hydrazone of β-diketone, 5-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)isophthalic acid (H3L), with zinc(II) nitrate hexahydrate in a mixture of DMF and water (1:1) under hydrothermal conditions affords the 1D coordination polymer [Zn(μ3-HL)(H2O)2]n ∙ nH2O (1), where one of the carboxylic groups links two Zn(II) centers in a bridging bidentate (syn-syn-type) mode and the remaining one ligates a third metal cation in a monodentate fashion. It was characterized by IR and NMR spectroscopies, ESI-MS, elemental and single-crystal X-ray crystal structural analyses. 1 acts as an efficient pre-catalyst for the Henry reaction at 40 °C in aqueous medium, providing β-nitroalcohols with good yields (67–86%) and diastereoselectivities (syn:anti 77:23–69:31).
- O 1º ciclo do ensino básico como "problema" de política educativa: definição de uma problemática em torno do conceito de "escola a tempo inteiro"Publication . Pires, CarlosNo centro desta reflexão teórica situa-se a conjuntura sociopolítica que fez (re)emergir o 1.º ciclo do ensino básico como “problema” de política educativa, ou seja, como terreno prioritário para o Estado, através do Governo, formular e executar um “modelo” de operacionalização da política de “Escola a Tempo Inteiro” (ETI). Analisamos esta política reportando-a a referenciais de representação de um “novo modelo educativo” (dimensão educativa), de um “novo paradigma de escola pública” (dimensão política) e de uma “nova conceção de administração da educação” (dimensão administrativa). O recurso ao quadro heurístico da “análise das políticas públicas” permite pôr em evidência as representações e a ação governativas.
- 2019 world of shipping Portugal. An international research conference on maritime affairs editorial “Leading the shipping industry into the future”Publication . Paixão Casaca, Ana Cristina; Loja, M.A.R.Background, the context and purpose of the study: The current Editorial addresses the evolutionary path of the shipping industry. It mentions its role throughout the years, identifies the leading market segments, refers to the different operational modes due to the inherent nature of the cargoes they carry and lists some trends that appear to have been shaping the maritime industry. Within the scope of this background, the Editorial claims that all maritime market segments face the same future challenges and lists a range of international legislation released by the International Maritime Organisation which industry players must comply with. Findings, the main results: Not/aplicable. Conclusions, brief summary and potential implications: The Editorial concludes by stating that the maritime industry will benefit from the implementation of innovative solutions and further claims that wrong decisions will have severe impacts on the finances of the shipping companies and the environment. Moreover, it presents in a brief way the papers published in this Special Issue, which were selected among the ones presented at the 2019 World of Shipping Portugal, an International Research Conference on Maritime Affairs, 21–22 November 2019, that took place at Hotel Riviera, in Carcavelos, Portugal.
- 2021 World of shipping Portugal: an international research conference on maritime afairs editorialPublication . Paixão Casaca, Ana Cristina; Loja, M.A.R.Currently, the shipping industry is at a crossroads. Although it has overcome numerous technological barriers and fnance and economic crises over the years, the industry is facing its most prominent challenge, which rests on fnding the most feasible solutions to deal with industry decarbonisation until 2050. Within this scope, the current Editorial addresses the issue of sulphur emissions that the industry faced with the entrance of the sulphur regulation on 1 January 2020 and draws attention to the road that the industry players need to cover to decarbonise the shipping industry. Innovative measures like the Poseidon Principles or the Sea Cargo Charter are in place, and industry players are coming together to fnd feasible solutions. Within this regulatory environment, the shipping industry also had to deal with the COVID-19 Pandemic. However, some market segments, such as the container and dry bulk ones, have managed to survive, which is not the case with the tanker market. Altogether, these events draw the industry to deal with the market, technology, and regulatory challenges and risks whose outcome is yet to be seen. The Editorial concludes by presenting briefy the papers published in this Special Issue, which were selected among the ones presented at the 2021 World of Shipping Portugal, an international research conference on maritime afairs, 28–29 January 2021, that took place online from Portugal to the World due to the Covid-19 pandemic.
- 25 años de investigación en didáctica de la lenguaPublication . Camps, AnnaNa celebração dos 25 anos da criação da Faculdade de Ciências da Educação da Universidade Autónoma de Barcelona, a autora proferiu uma conferência em que fez uma revisão geral das linhas prioritárias da investigação na área da Didática da Língua na referida universidade e na generalidade do contexto espanhol, salientando a situação da lecionação da didática na altura em que este âmbito de conhecimento era considerado área de investigação universitária. No início deste período, da Didática da Língua e Literatura, foi necessário definir o objeto da sua investigação, criar doutoramentos que cobrissem a dita investigação e homologar os professores nesta área. Durante estes 25 anos, as investigações sobre os processos de leitura e escrita, e sobre as situações sociais em que ocorrem, têm constituído o eixo principal dos estudos sobre o ensino e a aprendizagem da língua. Surge ultimamente uma nova linha, enraizada na capacidade metalinguística manifesta nos mesmos processos lecto-escritores, colocando o enfoque na necessidade de conhecimentos gramaticais por parte dos aprendizes. Destaca, no momento atual, o estudo da interrelação entre as diferentes habilidades linguísticas, por exemplo entre a leitura e a escrita, e entre a escrita e o conhecimento gramatical.
- 25 kV bipolar solid-state Marx generator for industrial food applicationsPublication . Luis Redondo; Pereira, Marcos TeotónioThe preliminary results from a bipolar industrial solidstate based Marx generator, developed for the food industry, capable of delivering 25 kV/250 A positive and negative pulses with 12 kW average power, are presented and discussed. This modular topology uses only four controlled switches per cell, 27 cells in total that can be charged up to 1000V each, the two extra cells are used for droop compensation. The triggering signals for all the switches are generated by a FPGA. Considering that biomaterials are similar to resistive type loads, experimental results from this new bipolar 25 kV modulator into resistive loads are presented and discussed.
- 2HDM Higgs-to-Higgs decays at next-to-leading orderPublication . Krause, Marcel; Muehlleitner, Margarete; Santos, Rui; Ziesche, HannaThe detailed investigation of the Higgs sector at present and future colliders necessitates from the theory side as precise predictions as possible, including higher-order corrections. An important ingredient for the computation of higher-order corrections is the renormalization of the model parameters and fields. In this paper we complete the renormalization of the two-Higgs-doublet model (2HDM) Higgs sector launched in a previous contribution with the investigation of the renormalization of the mixing angles alpha and beta. Here, we treat the renormalization of the mass parameter m(12)(2) that softly breaks the Z(2) symmetry of the 2HDM Higgs sector. We investigate the impact of two different renormalization schemes on the sample Higgs-to-Higgs decay H -> hh. This decay also allows us to analyze the renormalization of the mixing angles and to confirm the properties extracted before in other Higgs decays. In conclusion we find that a gauge-independent, process-independent and numerically stable renormalization of the 2HDM Higgs sector is given by the application of the tadpole-pinched scheme for the mixing angles a and beta and by the use of the modified minimal subtraction scheme for m(12)(2).
- 3 perguntas sobre... a abstençãoPublication . Montargil, FilipeO número oficial de leitores em condições de votar nestas eleições europeias era de 9681415. É desfasado da realidade ao ponto de falsear muito a taxa de abstenção e os resultados?