946 resultados para Synchronous demodulation
Resumo:
O presente trabalho trata do clculo da fora contra eletromotriz em carga de uma mquina sncrona com ms na superfcie do rotor (cuja forma de onda de fora contra eletromotriz no senoidal) sendo esta alimentada por correntes de fase cujas forma de onda so quadradas. Para conduzir esta investigao e calcular a fora contra eletromotriz da mquina em estudo, faz-se uma reviso sobre o Mtodo da Permeabilidade Fixa, mtodo este que permite a linearizao do ponto de operao da mquina. Dessa forma, as simulaes so conduzidas por meio do mtodo dos elementos finitos e do Mtodo da Permeabilidade Fixa, levando-se em conta a forma de onda da corrente de alimentao. Ateno especial dada ao modo que se analisa o fluxo concatenado e a forma de obteno da fora contra eletromotriz uma vez que as formas de onda do fluxo concatenado sofrem variaes abruptas a cada 60 eltricos. Alm destes parmetros, analisa-se tambm cada uma das parcelas do torque eletromagntico, i.e., torque mtuo, torque de relutncia e torque de borda, sendo realizado ao final do trabalho, uma comparao entre a soma da estimativa de cada parmetro com o valor do torque eletromagntico obtido por meio de uma simulao no linear.
Resumo:
O trabalho trata do projeto e do desenvolvimento de um processador de baixo consumo de potncia, de forma simplificada, explorando tcnicas de microarquitetura, para atingir menor consumo de potncia. apresentada uma sequncia lgica de desenvolvimento, a partir de conceitos e estruturas bsicas, at chegar a estruturas mais complexas e, por fim, mostrar a microarquitetura completa do processador. Esse novo modelo de processador comparado com estudos prvios de trs processadores, sendo o primeiro modelo sncrono, o segundo assncrono e o terceiro uma verso melhorada do primeiro modelo, que inclui minimizaes de registradores e circuitos. Uma nova metodologia de criao de padring de microcontroladores, baseada em reuso de informaes de projetos anteriores, apresentada. Essa nova metodologia foi criada para a rpida prototipagem e para diminuir possveis erros na gerao do cdigo do padring. Comparaes de resultados de consumo de potncia e rea so apresentadas para o processador desenvolvido e resultados obtidos com a nova metodologia de gerao de padring tambm so apresentados. Para o processador, um modelo, no qual se utilizam mltiplos barramentos para minimizar o nmero de ciclos de mquina por instruo, apresentado. Tambm foram ressaltadas estruturas que podem ser otimizadas e circuitos que podem ser reaproveitados para diminuir a quantidade de circuito necessrio na implementao. Por fim, a nova implementao comparada com os trs modelos anteriores; os ganhos obtidos de desempenho com a implementao dessas estruturas foram de 18% que, convertidos em consumo de potncia, representam economia de 13% em relao ao melhor caso dos processadores comparados. A tecnologia utilizada no desenvolvimento dos processadores foi CMOS 250nm da TSMC.
Resumo:
A demanda crescente de usurios de implante coclear (IC) e a distribuio irregular de profissionais especializados no pas, tornam necessrio o deslocamento de pacientes por longas distncias para os atendimentos, com consequente aumento dos custos diretos e indiretos do tratamento. A teleconsulta pode ser vista como uma alternativa em potencial para o acesso desta populao a estes servios. O presente ensaio clnico, randomizado, controlado, avaliou a eficcia da teleconsulta sncrona na programao dos sistemas de IC em usurios acompanhados em um Programa de Implante Coclear credenciado pelo Sistema nico de Sade. Participaram do estudo 79 indivduos com idades entre nove e 68 anos (mdia de 21,6), 41 do sexo masculino e 38 do sexo feminino, usurios de IC por um perodo de 0,58 a 24,75 anos. Estes indivduos foram divididos em dois grupos, de acordo com o modo de programao do IC: controle (n=40), que realizou o procedimento face a face e experimental (n=39) que realizou a teleconsulta sncrona. Treze fonoaudilogos sem experincia na programao do dispositivo atuaram como facilitadores das teleconsultas. Os procedimentos de programao do IC englobaram a telemetria de impedncia, definio dos nveis de estimulao eltrica, varredura e balanceamento dos eletrodos e ajuste fino da programao. Como medidas de avaliao de resultados foram utilizados o tempo dispendido na consulta, a audiometria em campo livre, o percentual de reconhecimento de sentenas no silncio e no rudo, o limiar de reconhecimento de sentenas no silncio e rudo (HINT-Brasil), a avaliao da satisfao com a consulta (escala MISS-21) e de aspectos pertinentes teleconsulta. Os facilitadores responderam as questes abertas referentes suas impresses dos atendimentos. Os dados foram analisados por meio de estatstica inferencial (testes t de Student, Wilcoxon, Mann-Whitney e correlao de Spearman). Os resultados mostraram que aps a programao do IC, em mdia, os participantes apresentaram limiares audiomtricos abaixo de 30 dB NA. O reconhecimento da fala ps atendimento, respectivamente para os grupos experimental e controle, foram de 81,3% e 83,8% (silncio) e 57,9% e 58,1% (rudo). No HINT-Brasil os resultados foram, respectivamente, para os grupos experimental e controle 61,4 dB NA e 61,8 dB NA (silncio) e relao S/R de 9,5 dB NA e 10,4 dB NA (rudo). Os participantes estiveram satisfeitos com a consulta. No houve diferena estatisticamente significativa entre os grupos em nenhuma das medidas de resultado. Todos os participantes relataram que teleconsulta pode ser vista como uma alternativa vivel ao atendimento face a face e sua aplicao clnica facilitaria a rotina de pacientes usurios de IC. Os facilitadores destacaram a sua importncia para o aprendizado e como ferramenta de formao continuada. A teleconsulta sncrona foi eficaz na programao dos sistemas de IC e amplamente aceita pelos usurios e profissionais.
Resumo:
O estudo do movimento pulmonar assunto de grande interesse na rea mdica. A observao direta do mesmo invivel, uma vez que o pulmo colapsa quando a caixa torcica aberta. Dentre os meios de observao indireta, escolheu-se o imageamento por ressonncia magntica em respirao livre e sem uso de nenhum gs para melhorar o contraste ou qualquer informao de sincronismo. Esta escolha prope diversos desafios, como: a superar a alta variao na qualidade das imagens, que baixa, em geral, e a suscetibilidade a artefatos, entre outras limitaes a serem superadas. Imagens de Tomografia Computadorizada apresentam melhor qualidade e menor tempo de aquisio, mas expem o paciente a nveis considerveis de radiao ionizante. apresentada uma metodologia para segmentao do pulmo, produzindo um conjunto de pontos coordenados. Isto feito atravs do processamento temporal da sequncia de imagens de RM. Este processamento consiste nas seguintes etapas: gerao de imagens temporais (2DSTI), transformada de Hough modificada, algoritmo de contornos ativos e gerao de silhueta. A partir de um dado ponto, denominado centro de rotao, so geradas diversas imagens temporais com orientaes variadas. proposta uma formulao modificada da transformada de Hough para determinar curvas parametrizadas que sejam sncronas ao movimento diafragmtico, chamados movimentos respiratrios. Tambm so utilizadas mscaras para delimitar o domnio de aplicao da transformada de Hough. So obtidos movimentos respiratrios que so suavizados pelo algoritmo de contornos ativos e, assim, permitem a gerao de contornos para cada quadro pertencente a sequncia e, portanto, de uma silhueta do pulmo para cada sequncia.
Resumo:
The marine stratigraphic record of the Granada Basin (central Betic Cordillera, Spain) is composed of three Late Miocene genetic units deposited in different sea-level contexts (from base to top): Unit I (sea-level rise), Unit II (high sea-level), and Unit III (low sea-level). The latter mainly consists of evaporites precipitated in a shallow-basin setting. Biostratigraphic analyses based on planktonic foraminifera and calcareous nannoplankton indicate four late Tortonian bioevents (PF1-CN1, PF2, PF3, and PF4), which can be correlated with astronomically-dated events in other sections of the Mediterranean. PF1-CN1 (7.89 Ma) is characterized by the influx of the Globorotalia conomiozea group (including typical forms of Globorotalia mediterranea) and by the first common occurrence of Discoaster surculus; PF2 (7.84 Ma) is marked by the first common occurrence of Globorotalia suterae; PF3 (7.69 Ma) is typified by the influx of dextral Neogloboquadrina acostaensis; and PF4 (7.37 Ma) is defined by the influx of the Globorotalia menardii group II (dextral forms). The PF1 event occurred in the upper part of Unit I, whereas PF2 to PF4 events occurred successively within Unit II. The age of Unit III (evaporites) can only be estimated in its lower part based on the presence of dextral Globorotalia scitula, which, together with the absence of the first common occurrence of the G. conomiozea group (7.24 Ma), points to the latest Tortonian. Comparisons with data from the other Betic basins indicate that the evaporitic phase of the Granada Basin (7.377.24 Ma) is not synchronous with those from the Lorca Basin (7.80 Ma) and the Fortuna Basin (7.6 Ma). In the Bajo Segura Basin (easternmost Betic Cordillera), no evaporite deposition occurred during the late Tortonian. The evaporitic unit of the Granada Basin (central Betics) records the late Tortonian restriction of the Betic seaway (the marine connection between the Atlantic and Mediterranean). The diachrony in the restriction of the Betic seaway is related to differing tectonic movements in the central and eastern sectors of the Betic Cordillera.
Resumo:
A detailed sedimentological and paleontological analysis of the uppermost Miocene (Messinian)Pliocene boundary at the northern border of the Bajo Segura Basin, southeastern Spain, was carried out in order to describe the evolution of the regional paleocoastline during the Pliocene reflooding of the Mediterranean immediately after the sea-level fall related to the Messinian Salinity Crisis. Multiple trace fossils typical of firm- and hardgrounds were recognized, allowing identification of Glossifungites (two different types), Entobia, and Gnathichnus ichnofacies. Trace-fossil analysis showed that lithology and media consistency exerted considerable control on the development of the different ichnocoenoses and that there was a clear decrease in hydrodynamic energy from a coastal to a shallow-water shelf environment related to progressive sea-level rise. Ichnological and sedimentological data provide evidence that the definitive flooding of the Mediterranean was rapid and synchronous throughout the northern margin of the Bajo Segura Basin. The following model for the Pliocene transgression in the study area is therefore proposed: (1) the marine ingression penetrated along the incised paleovalleys carved as a consequence of the fall in sea level, where the first two Pliocene systems were deposited (P0P1); (2) during the maximum flooding surface of the transgression, the sea overflowed the margins of the paleovalleys and extended throughout the entire northern margin of the basin; and (3) the third Pliocene system was deposited, forming the lower part of a highstand systems tract (P2).
Resumo:
Virtual and remote laboratories (VRLs) are e-learning resources that enhance the accessibility of experimental setups providing a distance teaching framework which meets the student's hands-on learning needs. In addition, online collaborative communication represents a practical and a constructivist method to transmit the knowledge and experience from the teacher to students, overcoming physical distance and isolation. This paper describes the extension of two open source tools: (1) the learning management system Moodle, and (2) the tool to create VRLs Easy Java Simulations (EJS). Our extension provides: (1) synchronous collaborative support to any VRL developed with EJS (i.e., any existing VRL written in EJS can be automatically converted into a collaborative lab with no cost), and (2) support to deploy synchronous collaborative VRLs into Moodle. Using our approach students and/or teachers can invite other users enrolled in a Moodle course to a real-time collaborative experimental session, sharing and/or supervising experiences at the same time they practice and explore experiments using VRLs.
Resumo:
Cette approche histomtrique traite la description des tissus constituants les tres vivants de deux espces vgtales vivaces (Lygeum spartum et Ammophila arenaria). Elle permettra daider comprendre certainement le comportement tant morphologique que physiologique de lespce vivante dans un biotope naturel. Prsentant des racines adaptatives labsorption de leau et des sels minraux du sol, ces deux espces montrent une fixation de la plante au substrat et laccumulation des rserves. Elles sont sous la dpendance de corrlations com plexes (trophiques, hormonales) qui stablissent entre lappareil souterrain et lappareil arien. Ltude histomtrique du Lygeum spartum et dAmmophila arenaria nous a permis de dterminer une nette diffrence entre les tissus des deux espces. Pour Ammophila arenaria, il existe de trs bonnes corrlations pour la majorit des tissus, expliquant ainsi une croissance cellulaire qui existe entre ces diffrents tissus.Le coefficient de corrlation est faible entre les diffrents tissus du Lygeum spartum. Le dveloppment des tissus de celle-ci nest pas synchrone, il montre toute mme une certaine htrogneit au niveau du dveloppement tissulaire des racines.
Resumo:
Aims: To determine the prevalence of endometriosis in epithelial ovarian cancers (EOC) and the association among their histological subtypes and with endometrial carcinoma. Methods: An observational cohort study performed in 192 patients operated on for EOC, 30 women with atypical endometriosis and 17 with p53 positive endometriosis. Data on associated endometriosis and endometrial carcinomas, histological subtypes, tumor stage, clinical and pathological characteristics and survival were analyzed. Results: Twenty cases of EOC (10.4%) had also endometriosis (12.7 in borderline and 9.3% in invasive cases), being a synchronous finding in most cases. Endometriosis associated with serous or mucinous EOC was observed in 2.2 and 2.7% of cases, respectively. However, this association was observed in 50 of endometrioid and 23% of clear cell EOC. Age, parity and tumor stage were lower in endometriosis-associated EOC patients; and all associated cases were type I (Kurman and Shih's classification) and showed better results in survival rate. Endometrial carcinoma was more frequently associated with endometrioid EOC (25%). Conclusions: There is a significant association between endometriosis, including atypical forms, and endometrioid and clear cell carcinomas, but not with other EOC histotypes. The presence of endometriosis in EOC suggests a better prognosis and an intermediate stage within the progression endometriosis-carcinoma.
Resumo:
Building Information Modelling (BIM) provides a shared source of information about a built asset, which creates a collaborative virtual environment for project teams. Literature suggests that to collaborate efficiently, the relationship between the project team is based on sympathy, obligation, trust and rapport. Communication increases in importance when working collaboratively but effective communication can only be achieved when the stakeholders are willing to act, react, listen and share information. Case study research and interviews with Architecture, Engineering and Construction (AEC) industry experts suggest that synchronous face-to-face communication is project teams preferred method, allowing teams to socialise and build rapport, accelerating the creation of trust between the stakeholders. However, virtual unified communication platforms are a close second-preferred option for communication between the teams. Effective methods for virtual communication in professional practice, such as virtual collaboration environments (CVE), that build trust and achieve similar spontaneous responses as face-to-face communication, are necessary to face the global challenges and can be achieved with the right people, processes and technology. This research paper investigates current industry methods for virtual communication within BIM projects and explores the suitability of avatar interaction in a collaborative virtual environment as an alternative to face-to-face communication to enhance collaboration between design teams professional practice on a project. Hence, this paper presents comparisons between the effectiveness of these communication methods within construction design teams with results of further experiments conducted to test recommendations for more efficient methods for virtual communication to add value in the workplace between design teams.
Resumo:
Tese de doutoramento, Sociologia (Sociologia da Cultura, Comunicao, e Estilos de Vida), Universidade de Lisboa, Instituto de Cincias Sociais, 2016
Resumo:
L'activit lectrique du coeur est initie par la gnration spontane de potentiels d'action venant des cellules pacemaker du noeud sinusal (SN). Toute dysfonction au niveau de cette rgion entrane une instabilit lectrique du coeur. La majorit des patients souffrant d'un noeud sinusal dficient ncessitent l'implantation chirurgicale d'un pacemaker lectronique; cependant, les limitations de cette approche incitent la recherche d'une alternative thrapeutique. La base molculaire des courants ioniques jouant un rle crucial dans l'activit du noeud sinusal sont de plus en plus connues. Une composante importante de l'activit des cellules pacemakers semble tre le canal HCN, responsable du courant pacemaker If. Le facteur T-box 3 (Tbx3), un facteur de transcription conserv durant le processus de l'volution, est ncessaire au dveloppement du systme de conduction cardiaque. De prcdentes tudes ont dmontr que dans diffrentes lignes cellulaires le Phorbol 12-myristate 13-acetate (PMA) active l'expression du gne codant Tbx3 via des ractions en cascade partant de la protine kinase C (PKC). L'objectif principal de cette tude est de tester si le PMA peut augmenter la frquence et la synchronisation de l'activit spontane du pacemaker biologique en culture. Plus prcisment, nous avons tudi les effets de l'exposition chronique au PMA sur l'expression du facteur de transcription Tbx3, sur HCN4 et l'activit spontane chez des monocouches de culture de myocytes ventriculaires de rats nonataux (MVRN). Nos rsultats dmontrent que le PMA augmente significativement le facteur transcription de Tbx3 et l'expression ARNm de HCN4, favorisant ainsi l'augmentation du rythme et de la stabilit de l'activit autonome. De plus, une diminution significative de la vitesse de conduction a t releve et est attribue la diminution du couplage intercellulaire. La diminution de la vitesse de conduction pourrait expliquer l'effet ngatif du PMA sur la synchronisation de l'activit autonome du pacemaker biologique. Ces rsultats ont t confirms par un modle mathmatique multicellulaire suggrant que des frquences et rsistances intercellulaires plus leve pourraient induire une activit plus stable et moins synchrone. Cette tude amne de nouvelles connaissances trs importantes destines la production d'un pacemaker biologique efficient et robuste.
Resumo:
Primary treatment of rectal cancer was the focus of the second St. Gallen European Organisation for Research and Treatment of Cancer (EORTC) Gastrointestinal Cancer Conference. In the context of the conference, a multidisciplinary international expert panel discussed and voted on controversial issues which could not be easily answered using published evidence. Main topics included optimal pretherapeutic imaging, indication and type of neoadjuvant treatment, and the treatment strategies in advanced tumours. Here we report the key recommendations and summarise the related evidence. The treatment strategy for localised rectal cancer varies from local excision in early tumours to neoadjuvant radiochemotherapy (RCT) in combination with extended surgery in locally advanced disease. Optimal pretherapeutic staging is a key to any treatment decision. The panel recommended magnetic resonance imaging (MRI) or MRI + endoscopic ultrasonography (EUS) as mandatory staging modalities, except for early T1 cancers with an option for local excision, where EUS in addition to MRI was considered to be most important because of its superior near-field resolution. Primary surgery with total mesorectal excision was recommended by most panellists for some early tumours with limited risk of recurrence (i.e. cT1-2 or cT3a N0 with clear mesorectal fascia on MRI and clearly above the levator muscles), whereas all other stages were considered for multimodal treatment. The consensus panel recommended long-course RCT over short-course radiotherapy for most clinical situations where neoadjuvant treatment is indicated, with the exception of T3a/b N0 tumours where short-course radiotherapy or even no neoadjuvant therapy were regarded to be an option. In patients with potentially resectable tumours and synchronous liver metastases, most panel members did not see an indication to start with classical fluoropyrimidine-based RCT but rather favoured preoperative short-course radiotherapy with systemic combination chemotherapy or alternatively a liver-first resection approach in resectable metastases, which both allow optimal systemic therapy for the metastatic disease. In general, proper patient selection and discussion in an experienced multidisciplinary team was considered as crucial component of care.
Resumo:
The knowledge of the current state of the economy is crucial for policy makers, economists and analysts. However, a key economic variable, the gross domestic product (GDP), are typically colected on a quartely basis and released with substancial delays by the national statistical agencies. The rst aim of this paper is to use a dynamic factor model to forecast the current russian GDP, using a set of timely monthly information. This approach can cope with the typical data ow problems of non-synchronous releases, mixed frequency and the curse of dimensionality. Given that Russian economy is largely dependent on the commodity market, our second motivation relates to study the eects of innovations in the russian macroeconomic fundamentals on commodity price predictability. We identify these innovations through a news index which summarizes deviations of ocal data releases from the expectations generated by the DFM and perform a forecasting exercise comparing the performance of dierent models.
Resumo:
Sortable silt mean grain sizes together with oxygen and carbon isotopic data produced on the benthic foraminiferal species Fontbotia wuellerstorfi are used to construct high-resolution records of near-bottom flow vigour and deep water ventilation at a core site MD02-2589 located at 2660 m water depth on the southern Agulhas Plateau. The results suggest that during glacial periods (marine oxygen isotope stages 2 and 6, MIS 2 and MIS 6, respectively), there was a persistent contribution of a well-ventilated water mass within the Atlantic to Indian oceanic gateway with a d13C signature similar to present-day Northern Component Water (NCW), e.g., North Atlantic Deep Water (NADW). The records of chemical ventilation and near-bottom flow vigor reflect changes in the advection of northern source waters and meridional variability in the location of the Antarctic Circumpolar Current and its associated fronts. We suggest that during Termination II (TII), changes in chemical ventilation are largely decoupled from near-bottom physical flow speeds. A mid-TII climate optimum is associated with a low-flow speed plateau concurrent with a period of increased ventilation shown in the benthic d13C of other Southern Ocean records but not in our benthic d13C of MD02-2589. The climate optimum is followed by a period of southern cooling around 128 ka coincident with a stronger influence of NCW to interglacial levels at around 124 ka. All proxy records show a near synchronous and rapid shift during the transition from MIS 5a-4 (73 ka). This large event is attributed to a rapid decrease in NADW influence and replacement over the Agulhas Plateau by southern source waters.
