Data transmission through channels pertubed by impulsive noise

Imperial Users onl

Coproducing leadership: a reason to resist destructive leaders

Purpose: Follower's individual differences have been receiving increased attention in studying destructive leadership because followers may enable or disable it. One of these yet under-researched features is the role of followers' leadership coproduction beliefs (a role construal) in explaining their resistance to destructive leaders. Departing from the proactive motivation theory, this paper explores the robustness of coproduction beliefs by testing its ability to predict followers' resistance to destructive leaders across four situations – abusive supervision, exploitative leadership, organization directed behaviors and laissez-faire. Design/methodology/approach: With a sample of 359 participants that answered a scenario-based survey, the present study tests the relationship between coproduction beliefs and resistance behaviors in the four mentioned groups, while controlling for alternative explanations. A multigroup analysis was conducted with PLS-SEM. Findings: Constructive resistance is always favored by coproduction beliefs independently of the leader's type of destructive behavior. Dysfunctional resistance, however, is sensitive to the leader's type of destructive behavior. Originality/value: This paper extends knowledge on the role of coproduction beliefs as an individual-based resource against destructive leaders.info:eu-repo/semantics/acceptedVersio

A reduced-CP approach to SC/FDE block transmission for broadband wireless communications

For conventional cyclic prefix (CP)-assisted single-carrier/frequency-domain equalization (SC/FDE) implementations, as well as for orthogonal frequency-division multiplexing (OFDM) implementations, the CP length is known to be selected on the basis of the expected maximum delay spread. Next, the data block size can be chosen to be large enough to minimize the CP overhead, yet small enough to make the channel variation over the block negligible. This paper considers the possibility of reducing the overall CP assistance, when transmitting sequences of SC blocks, while avoiding an excessively long fast Fourier transform window for FDE purposes and keeping good FDE performances through low-complexity, noniterative receiver techniques. These techniques, which take advantage of specially designed frame structures, rely on a basic algorithm for decision-directed correction (DDC) of the FDE inputs when the CP is not long enough to cope with the time-dispersive channel effects. More specifically, we present and evaluate a novel class of reduced-CP SC/FDE schemes, which takes advantage of a special frame structure for replacing "useless" CP redundancy by fully useful channel coding redundancy, with the help of the DDC algorithm. When using the DDC-FDE technique with these especially designed frame structures, the impact of previous decisions, which are not error-free, is shown to be rather small, thereby allowing a power-efficiency advantage (in addition to the obvious bandwidth-efficiency advantage) over conventional block transmission implementations under full-length CP. Additionally, the DDC algorithm is also shown to be useful to improve the power efficiency of these conventional implementations.Fundação para a Ciencia e Tecnologia (FCT), Centro de Análise e processamento de Sinais (CAPS

A turbo FDE technique for reduced-CP SC-based block transmission systems

For conventional cyclic-prefix (CP)-assisted block transmission systems, the CP length is selected on the basis of the expected maximum delay spread. With regard to single-carrier (SC)-based block transmission implementations, a full-length CP is recommendable, since it allows good performances through the use of simple frequency-domain equalization (FDE) techniques. In this letter, a soft-decision-directed correction (SDDC)-aided turbo FDE technique is presented for reduced-CP SC-based block transmission systems using conventional frame structures. The relations with some already known iterative FDE techniques are established, and a set of performance results is reported and discussed. The advantages of the proposed approach are emphasized, namely, the possibility of approximately achieving (besides the obvious bandwidth efficiency gain) the maximum power efficiency gain that a strong CP reduction allows.Fundação para a Ciencia e Tecnologia (FCT), Centro de Análise e processamento de Sinais (CAPS

Efetividade de um programa de enfermagem de reabilitação na capacitação do doente submetido a artroplastia total da anca

Enquadramento: A devolução da capacidade funcional é prioritária em pessoas submetidas a artroplastia total da anca, restituindo-lhes a sua autonomia e independência, capacitando-as nas suas AVD's, com recurso a um conjunto de estratégias e intervenções de enfermagem de reabilitação. Objetivos: Descrever o processo de desenvolvimento de competências comuns, específicas e de mestre em Enfermagem de Reabilitação e mestre, avaliar a efetividade das intervenções de um programa de reabilitação na capacitação de um doente submetido a ATA e verificar ganhos em saúde decorrentes do programa de reabilitação implementado. Metodologia: Implementação de um programa de intervenção de enfermagem de reabilitação a pessoas submetidas a ATA. Este projeto de intervenção baseia-se numa metodologia descritiva com abordagem quantitativa. A amostra é composta por sete participantes e foram utilizados os seguintes instrumentos de avaliação: Escala Numérica de Dor, Escala de Força Muscular- Lower, Escala de Equilíbrio - Tinetti, Escala de Risco de Queda - Morse, Escala de Medida de Independência Funcional (MIF) e a Goniometria. Resultados:Verificou-se entre os 1.º e 3.º momentos de avaliação, aumento da amplitude articular, diminuição do nível de dor, aumento da força muscular, do equilíbrio e do nível de independência funcional. Todos os participantes demonstraram melhoria global da sua funcionalidade. Conclusão: Os participantes do estudo evidenciaram ganhos de efetividade do programa de reabilitação. Verificou-se desenvolvimento de competências comuns e específicas do enfermeiro especialista em enfermagem de reabilitação, bem como competências de mestre, decorrente da participação neste projeto de intervenção

Avaliação da influência de antioxidantes na estabilização de biodiesel

O biodiesel é uma fonte de energia renovável, que se pode obter pela transformação dos resíduos domésticos, e é ambientalmente inócuo, e fácil de transportar, pois tem um ponto de fulgor elevado. Atualmente tem-se focado a atenção nos efeitos da oxidação do biodiesel causados pelo contato com o ar ambiente durante o seu armazenamento. Os produtores, fornecedores e consumidores, pretendem garantir que a qualidade do biodiesel e das suas misturas com combustíveis destilados do petróleo, mantém-se durante longos períodos de armazenamento. A maioria dos óleos vegetais e das gorduras animais, usados como matéria – prima, são triacilgliceróis com grupos ácido gordos de cadeia longa (C16 – C18) ligados por ligações éster a uma estrutura de glicerol. O objetivo deste estudo foi avaliar a eficiência do ácido gálhico e seus derivados alquilo ésteres aumentando a resistência relativa à oxidação do ácido linoléico, inibindo a peroxidação ácido gordos de cadeia longa insaturados. Outro objetivo foi estudar a taxa de inibição da auto-oxidação do ácido linoleico. Foi, ainda estudado o efeito que a concentração do antioxidante, tinha na estabilidade do ácido linoleico. No caso do ácido gálhico verificou-se que o aumento para o dobro da concentração do antioxidante utilizada, obtinha-se quase o dobro da taxa de inibição da oxidação do ácido linoleico. A auto-oxidação de ácido linoleico é acompanhada pela formação do seu dieno conjugado, o qual foi medido sua absorvância, durante 7 dias, por espetrofotometria de absorção UV a 234 nm. Uma diminuição da taxa de formação de dieno conjugado, indica o aumento da atividade antioxidante do composto adicionado à micela de ácido linoleico. Os resultados obtidos permitem concluir que de todos os antioxidantes testados o galhato de butilo é o que possibilita uma maior inibição da oxidação do ácido linoleico para as duas concentrações de antioxidantes testadas (0,1 mM e 1mM), obteve-se uma percentagem de inibição do ácido linoleico de 54,0% e 63,6%, respetivamente. O estudo comparativo da estabilização do ácido linoleico com o antioxidante de referência, o butil -hidroxitolueno, mostrou que este composto tem um poder de estabilização inferior a qualquer dos antioxidantes estudados. Os resultados deste estudo demonstraram que a utilização de compostos fenólicos, em especial o galhato de butilo, constitui uma boa alternativa para a estabilização de matrizes lipídicas, nomeadamente de combustíveis como o biodiesel.Biodiesel is a renewable fuel that is derived from domestic feedstock and described to be environmentally innocuous and safe to handle because it has a relatively high flash point. Currently, it has focused attention on the effects of biodiesel oxidation caused by contact with ambient air during storage. The manufacturers, suppliers and consumers want to ensure that the quality of biodiesel and their mixtures with petroleum distillate fuels, maintained for long storage periods. Most vegetable oils and animal fats, used as raw material, are triacylglycerols with fatty acid groups of long chain (C16 - C18) connected by ester linkages to a structure glycerol. The aim of this study was to examine the effectiveness of gallic acid and its alkyl esters derivatives in increasing the relative resistance to oxidation of linoleic acid by inhibiting unsaturated long-chain fatty acid peroxidation. Also, another aim, was to study the rate of inhibition of the linoleic acid autoxidation. The effect that concentration of the antioxidant had on the linoleic acid stability was investigated. Phenolic acids showed that the increase for the double of concentration resulted in improvement for the double on the the rate of inhibition of oxidation of linoleic acid. The linoleic acid autoxidation is accompanied by the formation of its conjugated diene, which absorbance was measured, for 7 days, by UV absorption spectrophotometry at 234 nm. A decrease in the rate of conjugated diene formation, indicate the increase of antioxidant activity of the compound added to the micelle of linoleic acid. The results obtained indicate that of all antioxidants tested the best antioxidant inhibiting the oxidation of linoleic acid is butyl gallate. Thus, for the two concentrations of antioxidants tested (0.1 mM and 1 mM), was obtained a percentage of linoleic acid inhibition of 54.0% and 63.6%, respectively. The comparative study of stability of linoleic acid with the reference antioxidant, butylhydroxytoluene, showed that this compound has a stabilizing power less than any of the antioxidants studied. The results of this study demonstrated that the use of phenolic compounds, especially butyl gallate, provides a good alternative for the stabilization of lipid matrices, such as biodiesel fuel

Fabrication of low electrical percolation threshold multi-walled carbon nanotube sensors using magnetic patterning

Soft robotics is an expanding area with multiple applications; however, building low-cost, soft, and flexible robots requires the development of sensors that can be directly integrated into the soft robotics fabrication process. Thus, the motivation for this work was the design of a low-cost fabrication process of flexible sensors that can detect touch and deformation. The fabrication process proposed uses a flexible polymer nanocomposite with permanent magnets strategically placed where the conductive electrodes should be. The nanocomposite is based on poly(dimethylsiloxane) (PDMS) and multi-walled carbon nanotubes (MWCNTs). The MWCNT contains ferromagnetic impurities remaining from the synthesis process, which can be used for magnetic manipulation. Several electrode geometries were successfully simulated and tested. The magnetic patterning was simulated, allowing the fabrication of conductive patterns within the composite. This fabrication process allowed the reduction of the electrical resistivity of the nanocomposites as compared to the composites with homogeneous MWCNT dispersion. It also allowed the fabrication of piezoresistive and triboelectric sensors at MWCNT concentration as low as 0.5 wt.%. The fabrication process proposed is flexible, allows the development of sensors for soft robotics, as well as monitoring large and unconventional areas, and may be adapted to different mould shapes and polymers at low cost.This research is part of the PhD project at the Doctoral Program in Advanced Materials and Processing—FEUP. We would like to thank CeNTI for providing resources (labs, equipment and consumables) to perform the fabrication and characterisation of the samples. The authors thank CEMUP for expert assistance (Rui Rocha) with SEM-EDS. IPC acknowledges the support of FCT through National Funds References UIDB/05256/2020 and UIDP/05256/2020

The Toll-dorsal pathway is required for resistance to viral oral infection in Drosophila

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors.Biotechnology and Biological Sciences Research Council (UK) grant BB/E005470/1, Fundação para a Ciência e Tecnologia fellowships: SFRH/BPD/65985/2009, SFRH/BD/51881/2012, SFRH/51885/2012

Study of the electrochemical reduction of amoebicide Teclozan and its amperometric determination in pharmaceutical formulations

Neste trabalho, a redução eletroquímica do amebicida Teclozan (TEC) foi estudada sobre um eletrodo de carbono vítreo em meio de acetonitrila. Eletrólises com potencial controlado foram realizadas visando, tanto a determinação do número de elétrons envolvidos na redução do fármaco, quanto a identificação dos produtos eletrogerados, os quais foram isolados por extração líquido-líquido e caracterizados por 1H RMN. Foi verificado que o TEC apresenta dois picos voltamétricos, cada um associado à quebra redutiva de duas ligações C-Cl. Em presença de um doador de prótons, foi observado que o primeiro pico voltamétrico em −1,8 V corresponde principalmente à redução dos grupamentos -CHCl2 a -CH2Cl; enquanto o segundo pico em −2,2 V é responsável pela redução dos grupos -CH2Cl a CH3, fornecendo como único produto o derivado totalmente desalogenado do TEC, com rendimentos entre 82 e 97%. Este trabalho descreve também o desenvolvimento de um método eletroanalítico baseado na detecção amperométrica do TEC em condições hidrodinâmicas, o qual forneceu um limite de detecção de 8,9 × 10-6 mol L-1.The electrochemical reduction of amoebicide Teclozan (TEC) was studied on a glassy carbon electrode in acetonitrile. Controlled-potential electrolyses were performed for coulometric and preparative purposes. The electrogenerated products were isolated by liquid-liquid extraction and characterized by 1H NMR. It was observed that TEC presents two voltammetric peaks, each one associated with the cleavage of two C-Cl bonds. In presence of a proton donor it was observed that the first peak at −1.8 V promotes mainly the reduction of the groups CHCl2 to CH2Cl and the second one at −2.2 V promotes the reduction of the groups CH2Cl to CH3 giving as the sole product the completely dechlorinated TEC derivative with yields between 82 and 97%. In addition, a comparative study between the analytical performance of voltammetric techniques and amperometric detection of TEC in hydrodynamic conditions was performed. The amperometric detection was more sensitive than all evaluated voltammetric techniques, providing a detection limit of 8.9 × 10-6 mol L-1.FAPESP; CAPES; FC