13 research outputs found

    Sensores passivos alimentados por transmissão de energia sem fios para aplicações de Internet das coisas

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    Nowadays, the Wireless Sensor Networks (WSNs) depend on the battery duration of the sensors and there is a renewed interest in creating a passive sensor network scheme in the area of Internet of Things (IoT) and space oriented WSN systems. The challenges for the future of radio communications have a twofold evolution, one being the low power consumption and, another, the adaptability and intelligent use of the available resources. Specially designed radios should be used to reduce power consumption, and adapt to the environment in a smart and e cient way. This thesis will focus on the development of passive sensors based on low power communication (backscatter) with Wireless Power Transfer (WPT) capabilities used in IoT applications. In that sense, several high order modulations for the communication will be explored and proposed in order to increase the data rate. Moreover, the sensors need to be small and cost e ective in order to be embedded in other technologies or devices. Consequently, the RF front-end of the sensors will be designed and implemented in Monolithic Microwave Integrated Circuit (MMIC).Atualmente, as redes de sensores sem fios dependem da duração da bateria e,deste modo, existe um interesse renovado em criar um esquema de rede de sensores passivos na área de internet das coisas e sistemas de redes de sensores sem fios relacionados com o espaço. Os desafios do futuro das comunicações de rádio têm uma dupla evolução, sendo um o baixo consumo de energia e, outro, a adaptação e o uso inteligente dos recursos disponíveis. Rádios diferentes dos convencionais devem ser usados para reduzir o consumo de energia e devem adaptar-se ao ambiente de forma inteligente e eficiente, de modo a que este use a menor quantidade de energia possível para estabelecer a comunicação. Esta tese incide sobre o desenvolvimento de sensores passivos baseados em comunicação de baixo consumo energético (backscatter) com recurso a transmissão de energia sem fios de modo a que possam ser usados em diferentes aplicações inseridas na internet das coisas. Nesse sentido, várias modulações de alta ordem para a comunicação backscatter serão exploradas e propostas com o objectivo de aumentar a taxa de transmissão de dados. Além disso, os sensores precisam de ser reduzidos em tamanho e económicos de modo a serem incorporados em outras tecnologias ou dispositivos. Consequentemente, o front-end de rádio frequência dos sensores será projetado e implementado em circuito integrado de microondas monolítico.Programa Doutoral em Engenharia Eletrotécnic

    Scrambler para VoIP

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    Mestrado em Engenharia Electrónica e TelecomunicaçõesA necessidade de se preservar a confidencialidade numa conversa telefónica é um facto dos nossos dias. Pretende-se com este trabalho dar uma resposta a este problema propondo um sistema original de scrambling do sinal no domínio das frequências. O sistema inclui uma troca de chaves públicas que geram uma chave secreta comum entre o emissor e o receptor, baseado no método de Diffie-Hellman. Além da implementação apresentam-se resultados de testes efectuados sobre o sistema de scrambling proposto associado a vários codecs de uso comum.The need to preserve confidentiality in a telephone conversation is, nowadays, a motive of concern for most of us. This work pretends to address this issue by proposing an original signal scrambling system in the frequency domain. The system includes a public key exchange which generates a common secret key, based on the Diffie-Hellman method, at the transmitter and the receiver. The implementation and some results of the proposed solution using common conventional codecs are presented

    Patient-physician discordance in assessment of adherence to inhaled controller medication: a cross-sectional analysis of two cohorts

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    We aimed to compare patient's and physician's ratings of inhaled medication adherence and to identify predictors of patient-physician discordance.(SFRH/BPD/115169/2016) funded by Fundação para a Ciência e Tecnologia (FCT); ERDF (European Regional Development Fund) through the operations: POCI-01-0145-FEDER-029130 ('mINSPIRERS—mHealth to measure and improve adherence to medication in chronic obstructive respiratory diseases—generalisation and evaluation of gamification, peer support and advanced image processing technologies') cofunded by the COMPETE2020 (Programa Operacional Competitividade e Internacionalização), Portugal 2020 and by Portuguese Funds through FCT (Fundação para a Ciência e a Tecnologia).info:eu-repo/semantics/publishedVersio

    Morphological and Postural changes in the foot during pregnancy and puerperium : a longitudinal study

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    The aim of this study is to observe the morphological and postural changes to the foot that take place during pregnancy and the puerperium. Method: In this descriptive, observational, longitudinal study, we analysed 23 pregnant women, with particular attention to morphological and postural aspects of the foot, at three time points during and after pregnancy: in weeks 9-13 of gestation, weeks 32-35 of gestation and weeks 4-6 after delivery. The parameters considered were changes in foot length, the Foot Posture Index (FPI) and the Hernández Corvo Index, which were analysed using a pedigraph and taking into account the Body Mass Index (BMI). The same procedure was conducted in each review. Results: The statistical analyses obtained for each foot did not differ significantly between the three measurement times. A pronator-type footprint was most frequently observed during the third trimester of pregnancy; it was predominantly neutral during the postpartum period. Statistically significant differences between the measurement times were obtained in the right foot for cavus vs. neutral foot type (between the first and third trimesters and also between the first trimester and the puerperium) (in both cases, p < 0.0001). Conclusions: Foot length increases in the third trimester and returns to normal in the puerperium. According to FPI findings, the third trimester of pregnancy is characterised by pronation, while the posture returns to neutrality during the postpartum period. During pregnancy, the plantar arch flattens, and this persists during the puerperium. The incidence of cavus foot increases significantly in the third trimester and in the puerperium

    Identification of clusters of asthma control: A preliminary analysis of the inspirers studies

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    This work was funded by ERDF (European Regional Development Fund) through the operations: POCI- -01-0145-FEDER-029130 (“mINSPIRERS—mHealth to measure and improve adherence to medication in chronic obstructive respiratory diseases - generalisation and evaluation of gamification, peer support and advanced image processing technologies”) co-funded by the COMPETE2020 (Programa Operacional Competitividade e Internacionalização), Portugal 2020 and by Portuguese Funds through FCT (Fundação para a Ciência e a Tecnologia).© 2020, Sociedade Portuguesa de Alergologia e Imunologia Clinica. All rights reserved. Aims: To identify distinct asthma control clusters based on Control of Allergic Rhinitis and Asthma Test (CARAT) and to compare patients’ characteristics among these clusters. Methods: Adults and adolescents (≥13 years) with persistent asthma were recruited at 29 Portuguese hospital outpatient clinics, in the context of two observational studies of the INSPIRERS project. Demographic and clinical characteristics, adherence to inhaled medication, beliefs about inhaled medication, anxiety and depression, quality of life, and asthma control (CARAT, >24 good control) were collected. Hierarchical cluster analysis was performed using CARAT total score (CARAT-T). Results: 410 patients (68% adults), with a median (percentile 25–percentile 75) age of 28 (16-46) years, were analysed. Three clusters were identified [mean CARAT-T (min-max)]: cluster 1 [27(24-30)], cluster 2 [19(14-23)] and cluster 3 [10(2-13)]. Patients in cluster 1 (34%) were characterised by better asthma control, better quality of life, higher inhaler adherence and use of a single inhaler. Patients in clusters 2 (50%) and 3 (16%) had uncontrolled asthma, lower inhaler adherence, more symptoms of anxiety and depression and more than half had at least one exacerbation in the previous year. Further-more, patients in cluster 3 were predominantly female, had more unscheduled medical visits and more anxiety symp-toms, perceived a higher necessity of their prescribed inhalers but also higher levels of concern about taking these inhalers. There were no differences in age, body mass index, lung function, smoking status, hospital admissions or specialist physician follow-up time among the three clusters. Conclusion: An unsupervised method based on CARAT--T, identified 3 clusters of patients with distinct, clinically meaningful characteristics. The cluster with better asthma control had a cut-off similar to the established in the validation study of CARAT and an additional cut-off seems to distinguish more severe disease. Further research is necessary to validate the asthma control clusters identified.publishersversionpublishe

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    The Portuguese Response

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    Funding Information: FUNDING SOURCES MÉDRTUG CHAIN Biobank: Fundação para a Ciência e Tecnologia (FCT) for CHRC funding -UID/04923/2020. CHUPorto: Fundação para a Ciência e Tecnologia (FCT) Grant nº 2P29O (Research 4 COVID-19).publishersversionpublishe

    Characterization of a large cluster of HIV-1 A1 infections detected in Portugal and connected to several Western European countries

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    HIV-1 subtypes associate with differences in transmission and disease progression. Thus, the existence of geographic hotspots of subtype diversity deepens the complexity of HIV-1/AIDS control. The already high subtype diversity in Portugal seems to be increasing due to infections with sub-subtype A1 virus. We performed phylogenetic analysis of 65 A1 sequences newly obtained from 14 Portuguese hospitals and 425 closely related database sequences. 80% of the A1 Portuguese isolates gathered in a main phylogenetic clade (MA1). Six transmission clusters were identified in MA1, encompassing isolates from Portugal, Spain, France, and United Kingdom. The most common transmission route identified was men who have sex with men. The origin of the MA1 was linked to Greece, with the first introduction to Portugal dating back to 1996 (95% HPD: 1993.6-1999.2). Individuals infected with MA1 virus revealed lower viral loads and higher CD4+ T-cell counts in comparison with those infected by subtype B. The expanding A1 clusters in Portugal are connected to other European countries and share a recent common ancestor with the Greek A1 outbreak. The recent expansion of this HIV-1 subtype might be related to a slower disease progression leading to a population level delay in its diagnostic.Supported by FEDER, COMPETE, and FCT by the projects NORTE-01-0145-FEDER-000013, POCI-01-0145-FEDER-007038 and IF/00474/2014; FCT PhD scholarship PDE/BDE/113599/2015; FCT contract FCT IF/00474/2014; European Funds through grant BEST HOPE (project funded through HIVERA, grant 249697) and by FCT PTDC/DTP-EPI/7066/2014. Global Health and Tropical Medicine Center are funded through FCT (UID/Multi/04413/2013). We would like to acknowledge all the patients and health care professionals from the Portuguese hospitals that contributed in some way to this study

    Characterisation of microbial attack on archaeological bone

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    As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved
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