• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 16
  • 1
  • 1
  • Tagged with
  • 18
  • 15
  • 13
  • 11
  • 8
  • 8
  • 8
  • 8
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

An?lise de superf?cies seletivas de freq??ncia para aplica??es em ondas milim?tricas

Medeiros, Gilcarlos Ribeiro de 24 September 2001 (has links)
Made available in DSpace on 2014-12-17T14:55:16Z (GMT). No. of bitstreams: 1 GilcarlosRM_Capa_ate_pag35.pdf: 10181958 bytes, checksum: 87e8f1bbd9c4787bded2b91e955fbdb0 (MD5) Previous issue date: 2001-09-24 / This work consists in the development of a theoretical and numerical analysis for frequency selective surfaces (FSS) structures with conducting patch elements, such as rectangular patches, thin dipoles and cross dipoles, on anisotropic dielectric substrates. The analysis is developed for millimeter wave band applications. The analytical formulation is developed in the spectral domain, by using a rigorous technique known as equivalent transmission line method, or immitance approach. The numerical analysis is completed through the use of the Galerkin's technique in the Fourier transform domain, using entire-domain basis functions. In the last decades, several sophisticated analytical techniques have been developed for FSS structure applications. Within these applications, it can be emphasized the use of FSS structures on reflecting antennas and bandpass radomes. In the analysis, the scattered fields of the FSS geometry are related to the surface induced currents on the conducting patches. After the formulation of the scattering problem, the numerical solution is obtained by using the moment method. The choice of the basis functions plays a very important role in the numerical efficiency of the numerical method, once they should provide a very good approximation to the real current distributions on the FSS analyzed structure. Thereafter, the dyadic Green's function components are obtained in order to evaluate the basis functions unknown coefficients. To accomplish that, the Galerkin's numerical technique is used. Completing the formulation, the incident fields are determined through the incident potential, and as a consequence the FSS transmission and reflection characteristics are determined, as function of the resonant frequency and structural parameters. The main objective of this work was to analyze FSS structures with conducting patch elements, such as thin dipoles, cross dipoles and rectangular patches, on anisotropic dielectric substrates, for high frequency applications. Therefore, numerical results for the FSS structure main characteristics were obtained in the millimeter wave bando Some of these FSS characteristics are the resonant / Este trabalho consiste na an?lise te?rica e num?rica de superf?cies seletiva de freq??ncia com elementos do tipo patch retangular, dipolo fino e dipolo cruzado sobre substratos diel?tricos anisotr?picos, para a faixa de freq??ncias de ondas milim?tricas. A formula??o anal?tica ? realizada por uma t?cnica de abordagem do dom?nio espectral conhecido como m?todo de linha de transmiss?o equivalente ou m?todo da imit?ncia. A an?lise num?rica ? solucionada atrav?s do uso da t?cnica num?rica de Galerkin no dom?nio da transformada de Fourier, utilizando-se fun??es de base de dom?nio inteiro. Nas ?ltimas d?cadas, muitas aplica??es e t?cnicas anal?ticas sofisticadas t?m sido desenvolvidas para a caracteriza??o das FSS. Dentre as aplica??es, pode-se destacar a utiliza??o de FSS em antenas refletoras e em redomes passa-faixa. Primeiramente relaciona-se os campos espalhados da FSS com as correntes superficiais induzidas na patch. Ap?s a dedu??o realizada para o problema de espalhamento, pode-se obter a solu??o num?rica da mesma atrav?s do m?todo dos momentos. A escolha das fun??es de base ? de grande import?ncia para a efici?ncia num?rica do m?todo, devendo se aproximar ao m?ximo das caracter?sticas f?sica das distribui??es de corrente na estrutura analisada
12

Proposta de algoritmo para detec??o de vazamentos em oleodutos utilizando an?lise freq?encial de sinais de press?o

Azevedo, Fabiano Medeiros de 23 October 2009 (has links)
Made available in DSpace on 2014-12-17T14:55:40Z (GMT). No. of bitstreams: 1 FabianoMA.pdf: 3389870 bytes, checksum: 6be9485b031563d3dfbff4f86c5c0c69 (MD5) Previous issue date: 2009-10-23 / Petr?leo Brasileiro SA - PETROBRAS / Pipeline leak detection is a matter of great interest for companies who transport petroleum and its derivatives, in face of rising exigencies of environmental policies in industrialized and industrializing countries. However, existing technologies are not yet fully consolidated and many studies have been accomplished in order to achieve better levels of sensitivity and reliability for pipeline leak detection in a wide range of flowing conditions. In this sense, this study presents the results obtained from frequency spectrum analysis of pressure signals from pipelines in several flowing conditions like normal flowing, leakages, pump switching, etc. The results show that is possible to distinguish between the frequency spectra of those different flowing conditions, allowing recognition and announce of liquid pipeline leakages from pressure monitoring. Based upon these results, a pipeline leak detection algorithm employing frequency analysis of pressure signals is proposed, along with a methodology for its tuning and calibration. The proposed algorithm and its tuning methodology are evaluated with data obtained from real leakages accomplished in pipelines transferring crude oil and water, in order to evaluate its sensitivity, reliability and applicability to different flowing conditions / A detec??o de vazamentos em dutos ? assunto de grande interesse para empresas que realizam o transporte de petr?leo e seus derivados, tendo em vista o crescente rigor da legisla??o ambiental nos pa?ses industrializados e em processo de industrializa??o. No entanto, as tecnologias existentes hoje ainda n?o est?o plenamente consolidadas e estudos v?m sendo realizados com vistas a atingir maiores n?veis de sensibilidade e confiabilidade para a detec??o de vazamentos em uma ampla variedade de regimes de escoamento. Neste sentido, este estudo apresenta os resultados obtidos com a an?lise do espectro de freq??ncia de sinais de press?o de oleodutos em diversas situa??es de escoamento, tais como escoamento normal, vazamentos, partida e parada de bombas, etc. Os resultados indicam que ? poss?vel diferenciar o espectro freq?encial dessas diferentes condi??es de escoamento, o que permite reconhecer e indicar a ocorr?ncia de vazamentos em dutos transportando fluidos l?quidos a partir da monitora??o de sua press?o. Com base nestes resultados, s?o propostos um algoritmo para detec??o de vazamentos em dutos utilizando a an?lise freq?encial de sinais de press?o e uma metodologia para sintonia e calibra??o deste algoritmo. O algoritmo e a metodologia de sintonia propostos s?o avaliados com dados obtidos a partir de vazamentos reais provocados em dutos transferindo petr?leo e ?gua, a fim de avaliar sua sensibilidade, confiabilidade e aplicabilidade para diferentes condi??es de escoamento
13

An?lise da efici?ncia espectral considerando a duplexa??o e o perfil de tr?fego para bandas licenciadas / Analysis of the espectral efficiency considering duplexing and the profile of traffic in licensed bands

Savoine, M?rcia Maria 06 February 2009 (has links)
Made available in DSpace on 2016-04-04T18:31:25Z (GMT). No. of bitstreams: 1 Marcia Maria Savoine.pdf: 2175715 bytes, checksum: 355bcfef34d422002fc47ef44d62e191 (MD5) Previous issue date: 2009-02-06 / This work presents the comparison made through simulations of discreet events, accomplished with the software ARENA, the techniques of Time Division Duplex (TDD) and Frequency Division Duplex (FDD). Techniques present in the pattern IEEE 802.16 and used by WiMAX in the bi-directional channels of uplink and downlink. The simulation model considered in the line of arrival of the services the concept FIFO (First-In, First-Out) and the simulations were accomplished considering five applications (Streaming, Download, Web, E-mail and Small-Transaction) for downlink and uplink. The number of channels in the Base Station varied from 4 to 60, with a throughput of 600 kbps. The regarded efficiency parameter was the minimum number of channels necessary in each one of the standard channels. The simulations were accomplished in three sceneries., In the first scenery it was considered the same profile of traffic for downlink and uplink, in the second scenery a traffic of downlink 2, 5, 10 and 15 times larger than the one of uplink. And, in the third scenery it was considered different proportions of traffics varying from 2 to 5 times more, 5 to 10 times more and from 10 to 15 times more. The analyses were done considering as efficiency parameter the converge of the waiting time of the users. ,It was verified that in asymmetric data traffic, the TDD technique was more efficient and there were spectrum idleness in the FDD technique. / Este trabalho apresenta a compara??o efetuada por meio de simula??es de eventos discretos, realizadas com o software ARENA, das t?cnicas de Duplexa??o por Divis?o no Tempo (TDD) e Duplexa??o por Divis?o da Freq??ncia (FDD), t?cnicas presentes no padr?o IEEE 802.16 e utilizadas pelo WiMAX nos canais bidirecionais de uplink e downlink. O modelo de simula??o considerou na fila de chegada dos servi?os o conceito FIFO (First-In, First-Out) e as simula??es foram realizadas considerando cinco aplica??es (Streaming, Download, Web, E-mail e Small-Transaction) para downlink e uplink. O n?mero de canais na Base Station variou de 4 a 60, com um throughput de 600 kbps. O par?metro de efici?ncia considerado foi o n?mero m?nimo de canais necess?rio em cada um dos canais padr?es. As simula??es foram realizadas em tr?s cen?rios, sendo que, no primeiro cen?rio se considerou o mesmo perfil de tr?fego para downlink e uplink, no segundo cen?rio com tr?fego de downlink 2, 5, 10 e 15 vezes maior que o de uplink. E, no terceiro cen?rio com propor??es variadas de tr?fegos variando de 2 a 5 vezes mais, 5 a 10 vezes mais e de 10 a 15 vezes mais. Realizadas as simula??es foram feitas as an?lises dos desempenhos, tomando como par?metro de efici?ncia a taxa de chegada e o tempo de espera do usu?rio perante aplica??es t?picas utilizadas na tecnologia de banda licenciada WiMAX, que segue este padr?o. A an?lise efetuada permitiu identificar, dada estas condi??es de tr?fego, qual das t?cnicas seria a mais indicada. Constatou-se ainda que em tr?fego de dados assim?tricos a t?cnica TDD se apresentou mais eficiente e, observou-se existir ociosidade de espectro na t?cnica FDD.
14

Reatividade a diferentes tipos de estresse em equinos atletas / Reactivity to different types of stress in equine athletes

Villas Boas, Julia Dias 28 April 2017 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-09-12T18:08:44Z No. of bitstreams: 1 2017 - Julia Dias Villas Boas.pdf: 1378660 bytes, checksum: 2a1537e1b92056b0327c8e50b73feb34 (MD5) / Made available in DSpace on 2018-09-12T18:08:44Z (GMT). No. of bitstreams: 1 2017 - Julia Dias Villas Boas.pdf: 1378660 bytes, checksum: 2a1537e1b92056b0327c8e50b73feb34 (MD5) Previous issue date: 2017-04-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The horse has a natural predisposition for the sport, however, its use in competitions can result in stress related problems that impair its sporting performance and especially its health. In this way it is fundamental not only to understand how the different risk and resilience factors to different stressors influence the response to stress, but also to develop strategies that can prevent or minimize the deleterious effects of stress. In this sense, acupuncture is an ancient technique of Traditional Chinese Medicine that has been used in the treatment and prevention of stress-related diseases. The present study proposed the use of two models of stress: one physical (physical exercise) and another psychological (startle model) to verify the reactivity to the stress of athletes horses. In addition, it was also evaluated if horses of different sporting modalities present different psychological stress responses and if acupuncture can alter the responses to physical stress. In the experiment 1, 16 Thoroughbred race horses were submitted to a exercise in the field of high intensity and short duration (12 m / s, 4 min). The RR intervals for analysis of the Heart Rate Variability were acquired through the Polar Equine ? heart rate monitor and blood samples were collected before and immediately after 2h, 4h, 6h, and 24h after exercise. The exercise promoted autonomic alterations in the sympatho-vagal balance since it significantly increased the low frequency component (LF), the heart rate and the LF / HF ratio, and decreased the high frequency component (HF) (p <0.01). There was an increase in hematocrit, plasma proteins, glucose and plasma lactate immediately after exercise (p <0.001). There was an increase (p <0.01) in serum cortisol values after 30 minutes, returning to baseline values after 60 min. However, no significant difference was observed in plasma cytokines IL-1? and IL-6 between moments after exercise and baseline. In experiment 2, horses of the experimental group 1 after exercise were randomly divided into two groups: CTL (C2): Control (without manipulation) and ACUP (C2)): animals submitted to weekly sessions of acupuncture at points VG1, C7, VG20 and B52 for 10 weeks. After the treatment period the animals repeated the same exercise and the same parameters were analyzed. Acupuncture reduced the LF / HF ratio, promoting a faster recovery of the animals, showing no influence on the other parameters analyzed. In the experiment 3, 24 equines were used, from three equestrian modes: Polo (PSI) (n = 9), Dressage (Brazilian Horse Riding) (n = 6) and Endurance (n=6) were subjected to the experimental model of startling through the abrupt opening of an umbrella. The results showed that endurance horses presented a significantly less intense startle-induced autonomic response than Polo and Dressage horses (lower LF / HF ratio at the time of the jump), paradoxically Enduro horses have cortisol levels in response in response to the startle than Polo horses. However, there was no difference between the modalities in the behavioral response after the startle, and Polo horses had significantly higher baseline levels of cortisol than the other modalities and did not change their cortisol levels in response to stress. Thus, we can conclude that 1) the exercise in the field of high intensity and short duration promoted adaptive changes characteristic of stress, being able to be used in studies of reactivity to stress in race horses; 2) acupuncture has a modulating effect on the stress-induced autonomic response in athletic horses, and 3) the equestrian modalities of Dressage, Polo and Endurance present different stress reactivity / O cavalo tem uma predisposi??o natural para o esporte, no entanto, o seu uso em competi??es pode resultar em problemas relacionados ao estresse que prejudicam seu desempenho esportivo e principalmente a sua sa?de. Desta forma ? fundamental n?o apenas entender como os diferentes fatores de risco e de resili?ncia a diferentes estressores influenciam a resposta ao estresse, como tamb?m desenvolver estrat?gias que possam prevenir ou minimizar os efeitos delet?rios do estresse. Neste sentido a acupuntura ? uma t?cnica milenar da Medicina Tradicional Chinesa que tem sido utilizada no tratamento e preven??es de doen?as relacionadas ao estresse. O presente estudo prop?s o uso de dois modelos de estresse: um f?sico (exerc?cio f?sico) e outro psicol?gico (modelo de sobressalto) para verificar a reatividade ao estresse de cavalos atletas. Al?m disso, tamb?m foi avaliado se cavalos de diferentes modalidades esportivas apresentam respostas ao estresse de psicol?gico distintas e se acupuntura pode alterar as respostas ao estresse f?sico. No experimento 1, 16 equinos de corrida da ra?a Puro Sangue Ingl?s foram submetidos ao exerc?cio a campo de alta intensidade e curta dura??o (12 m/s, 4min). Os intervalos RR para an?lise da Variabilidade da Frequencia Card?aca foram adquiridos atrav?s do frequenc?metro card?aco Polar Equine? e as amostras de sangue foram coletadas antes e, imediatamente, 2h, 4h, 6h, e 24h ap?s o exerc?cio. O exerc?cio promoveu altera??es auton?micas no balan?o simpato-vagal uma vez que aumentou significativamente o componente de baixa frequ?ncia (LF), a frequ?ncia card?aca e a raz?o LF/HF e diminuiu o componente de alta frequ?ncia (HF) (p < 0.01). Houve aumento do hemat?crito, das prote?nas plasm?ticas, glicose e lactato plasm?tico imediatamente ap?s o exerc?cio (p < 0.001). Houve aumento (p<0.01) nos valores s?ricos de cortisol ap?s 30 minutos, retornando aos valores basais ap?s 60min. No entanto, n?o foi observado diferen?a significativa nas citocinas plasm?ticas IL-1? e IL-6 entre os momentos ap?s exerc?cio e o momento basal. No experimento 2: os equinos do experimento 1 ap?s o exerc?cio foram aleatoriamente divididos em dois grupos: CTL (C2): Controle (sem manipula??o) e ACUP (C2)ACUP (C2): animais submetidos a sess?es semanais de acupuntura nos pontos VG1, C7, VG20 e B52 durante 10 semanas. Ap?s o per?odo de tratamento os animais repetiram o mesmo exerc?cio e foram analisados os mesmos par?metros. A acupuntura reduziu a raz?o LF/HF, promovendo uma recupera??o mais r?pida dos animais n?o apresentando influ?ncia nos demais par?metros analisados. No experimento 3, foram utilizados 24 equinos, pertencentes a tr?s modalidades equetres: P?lo (ra?a PSI) (n=9), Adestramento (ra?a Brasileiro de Hipismo) (n=6) e Enduro (Puro Sangue ?rabe) (n=9) submetidos ao modelo experimental de sobressalto atrav?s da abertura abrupta de um guarda-chuva. Os resultados mostraram que cavalos de enduro apresentaram resposta auton?mica induzida pelo sobressalto significativamente menos intensa que cavalos de Polo e Adestramento (menor raz?o LF/HF no momento do sobressalto), paradoxalmente cavalos de Enduro possuem n?veis de cortisol em resposta ao sobressalto mais altos que cavalos de Polo. N?o houve diferen?a entre as modalidades na resposta comportamental ap?s o sobressalto, no entanto cavalos de P?lo apresentam n?veis basais de cortisol significativamente mais altos que as demais modalidades e n?o variaram seus n?veis de cortisol em resposta ao estresse. Dessa forma, podemos concluir que 1) o exerc?cio a campo de alta intensidade e curta dura??o promoveu altera??es adaptativas caracter?stica de estresse, podendo ser utilizado em estudos de reatividade ao estresse em cavalos de corrida; 2) a acupuntura tem um efeito modulador da resposta auton?mica induzida pelo estresse em cavalos atletas e 3) as modalidades equestres de Adestramento, Polo e enduro apresentam reatividade ao estresse distintas
15

Fluidic Tuning of a Four-Arm Spiral-Based Frequency Selective Surface

Wells, Elizabeth Christine 2011 May 1900 (has links)
Frequency selective surfaces (FSSs) provide a variety of spatial filtering functions, such as band-pass or band-stop properties in a radome or other multilayer structure. This filtering is typically achieved through closely-spaced periodic arrangements of metallic shapes on top of a dielectric substrate (or within a stack of dielectric materials). In most cases, the unit cell size, its shape, the substrate parameters, and the inter-element spacing collectively impact the response of the FSS. Expanding this design space to include reconfigurable FSSs provides opportunities for applications requiring frequency agility and/or other properties. Tuning can also enable operation over a potentially wider range of frequencies and can in some cases be used as a loading mechanism or quasi-ground plane. Many technologies have been considered for this type of agility (RF MEMS, PIN diodes, etc.). This includes the recent use of microfluidics and dispersions of nanoparticles, or fluids with controllable dielectrics, which have entered the design space of numerous other EM applications including stub-tuners, antennas, and filters. In this work they provide a material based approach to reconfiguring an FSS. An FSS based on a four-arm spiral with tunable band-stop characteristics is presented in this work. A thin colloidal dispersion above each element provides this tuning capability. The radial expansion and contraction of this dispersion, as well as the variable permittivity of the dispersion, are used to load each element individually. This design incorporates thin fluidic channels within a PDMS layer below the substrate leading to individual unit cells that provide a closed pressure-driven subsystem that contains the dispersion. With the capability to individually control each cell, groups of cells can be locally altered (individually or in groups) to create gratings and other electromagnetically agile features across the surface or within the volume of a radome or other covering. Simulations and measurements of an S-band tunable design using colloidal Barium Strontium Titanate dispersed Silicone oil are provided to demonstrate the capability to adjust the stop-band characteristics of the FSS across the S-band.
16

Estudos anal?ticos dos grafoelementos do eletroencefalograma em sono: fusos do sono, ondas agudas do v?rtex e o gradiente de freq??ncia e amplitude, como indicadores de comprometimento neurol?gico na crian?a

Auc?lio, Carlos Nogueira 28 December 2006 (has links)
Made available in DSpace on 2014-12-17T14:13:20Z (GMT). No. of bitstreams: 1 CarlosNA.pdf: 2422732 bytes, checksum: f5d47defbd8e5b492fe5d2975c8286ee (MD5) Previous issue date: 2006-12-28 / Innumerable studies have focused been reported on the sleep spindles (SS), Sharp Vertex Waves (SVW) and REM, NREM Sleep as indicators interpreting EEG patterns in children. However, Frequency and Amplitud Gradient (FAG) is rarely cited sleep parameter in children,that occurs during NREM Sleep. It was first described by Slater and Torres, in 1979, but has not been routinely evaluated in EEG reports. The aim of this study was to assess the absence of SS, SVW and FAG, as an indication of neurological compromise in children. The sample consisted of 1014 EEGs of children referred to the Clinical Neurophysiology Laboratory, Hospital Universit?rio de Bras?lia (HUB), from January 1997 to March 2003, with ages ranging from 3 months to 12 years old, obtained in spontaneous sleep or induced by choral hydrate. The study was transversal and analytical, in which, visual analysis of EEG traces was perfumed individually and independently by two electroencephalographers without prior knowledge of the EEG study or neurological findings. After EEG selection, the investigators analyzed the medical reports in order to define and correlate neurological pattern was classified according to the presence or absence of neurological compromise, as Normal Neurological Pattern (NNP), and Altered Neurological Pattern (ANP) respectively. From the visual analysis of the EEG(s), it was possible to characterize 6 parameters: 1- FAG present (64,1%); 2- FAG absent (35,9%); 3 - normal SS (87,9%); 4 - altered SS s (12,1%); 5 - normal SVW s (95,7%); 6 - altered SVW s (4,3%). The prevalence of well-formed FAG is found in the 3 months to 5 years age group in the children with NNF. FAG was totally absent from the age of 10 years. When comparing the three sleep graphielements, it was observed that SVW and SS were predominant in children with NNF. However, FAG absent was more prevalent in the ANF than in altered SS an SVW. The statistical analysis showed that there is a strong association of FAG absent, with isolated alteration, in ANF patients, in that the prevalence ratio was 6,60. The association becomes stronger when FAG absent + altered SS(s) is considered (RP= 6,68). Chi-square test, corrected by Yates technique, showed a highly significant relation for FAG &#961;= 0,00000001, for error X of 5%, or else the 95% confidence interval (&#961;<0,05). Thus, the FAG absent were more expressive in ANF patient than altered SS(s) and SVW(s). The association becomes stronger in order to establish a prognostic relation, when the FAG is combined with the SS. The results os this study allow us to affirm that the FAG, when absent at ages ranging from 3 months to 5 years , is an indication of neurological compromise. FAG is an age-dependent EEG parameter and incorporated systematically, in the interpretation criteria of the EEG of children s sleep, not only in the maturational point of view, but also neurological disturbances with encephalic compromise / In?meras pesquisas t?m focalizado periodicamente os fusos do sono (FS), as ondas agudas do v?rtex (OAV), o complexo K e o padr?o do sono REM e NREM como indicadores de avalia??o eletrencefalogr?fica da inf?ncia. O GFA ? um padr?o EEG do sono de crian?as que ocorre durante o sono NREM, raramente citado na literatura, e que, descrito pela primeira vez por Slater e Torres, em 1979, e n?o devidamente valorizado na rotina dos laudos EEG. Nas montagens referenciais ? caracterizado por uma progressiva diminui??o de voltagem e aumento de freq??ncia na dire??o p?stero-anterior. O objetivo desta tese, foi analisar o gradiente de freq??ncia e amplitude, um padr?o EEG do sono de crian?as que ocorre durante o sono NREM; estudar os fusos do sono(FS), ondas agudas do v?rtex (OAV), como indicadores de comprometimento neurol?gico. A popula??o de estudo constitui-se de 1014 EEG de crian?as atendidas no Laborat?rio de Neurofisiologia Cl?nica do Hospital Universit?rio de Bras?lia (HUB) no per?odo de janeiro de 1997 a mar?o de 2003, nas faixas et?rias de 3 meses a 12 anos de idade, obtidos em sono espont?neo ou induzido por hidrato de cloral. O tipo de ensaio foi transversal-anal?tico, onde os EEG foram avaliados independentemente por 2 examinadores sem pr?vio conhecimento do padr?o neurol?gico e da indica??o cl?nica. Ap?s an?lise visual do EEG, foram pesquisados os prontu?rios m?dicos de todas as crian?as inclu?das no estudo, a fim de definir e associar o padr?o neurol?gico com os par?metros fusos do sono, ondas agudas do v?rtex, e GFA. O padr?o neurol?gico foi classificado segundo a presen?a ou aus?ncia de comprometimento neurol?gico em padr?o neurol?gico normal (PNN) e padr?o neurol?gico anormal (PNA), respectivamente. Com base na an?lise visual dos EEG, foi caracterizado o GFA em duas categorias: 1) GFA presente (64,1%); 2) GFA ausente ( 35,9%); 3) FS normais (87,9%); 4) FS alterados (12,1%); 5) OAV normais (95,7%); 6) OAV alteradas (4,3%). A melhor express?o do GFA presente com PNN ocorreu nas faixas et?rias de 3 meses a 5 anos. Observou-se tamb?m que o GFA torna-se ausente a partir dos 10 anos de idade em crian?as com PNN. Comparando os 3 grafoelementos do sono, as OAV e FS, foram respectivamente predominantes nas crian?as com PNN. A an?lise estat?stica mostrou que existe uma forte associa??o de aus?ncia de GFA, como altera??o isolada, nos pacientes com PNA, uma vez que a raz?o de preval?ncia foi de 6,60. A associa??o torna-se mais forte, quando se considerou GFA ausente + FS alterados (RP=11,9) e GFA ausente + FS alterados + OAV alterados (RP= 6,68). O teste do qui-quadrado, com corre??o pela t?cnica de Yates, mostrou uma rela??o altamente significativa, quando envolvido o GFA. Assim, o GFA ausente foi mais expressivo no PNA que os FS e as OAV alterados. A associa??o se torna ainda mais forte a ponto de estabelecer uma rela??o com valor progn?stico, quando o GFA se encontra-se combinado com o FS. Embora estatisticamente significante, n?o houve associa??o quando as OAV se encontra isoladas em compara??o aos demais par?metros. Os dados obtidos neste estudo permitem afirmar que, entre os grafo- elementos do sono, o GFA, quando ausente nas faixas et?rias de 3 meses a 5 anos, ? um indicador de comprometimento neurol?gico, sendo tal conclus?o mais expressiva do que os par?metros FS e OAV. O GFA ? um par?metro idade dependente e deve ser valorizado e incorporado, sistematicamente, aos crit?rios de interpreta??o do tra?ado EEG do sono de crian?as, tanto no ponto de vista da avalia??o maturacional como dos dist?rbios neurol?gicos com comprometimento encef?lico
17

Uma proposta de FSS fractal com geometria simplificada

Montalv?o, Emanuele da Silva Rodrigues 21 December 2010 (has links)
Made available in DSpace on 2014-12-17T14:55:47Z (GMT). No. of bitstreams: 1 EmanueleSRM_DISSERT.pdf: 2423953 bytes, checksum: 516a98f7f1136b2e57265165c2a43b20 (MD5) Previous issue date: 2010-12-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Frequency Selective Surfaces (FSS) are periodic structures in one or two dimensions that act as spatial filters, can be formed by elements of type conductors patches or apertures, functioning as filters band-stop or band-pass respectively. The interest in the study of FSS has grown through the years, because such structures meet specific requirements as low-cost, reduced dimensions and weighs, beyond the possibility to integrate with other microwave circuits. The most varied applications for such structures have been investigated, as for example, radomes, antennas systems for airplanes, electromagnetic filters for reflective antennas, absorbers structures, etc. Several methods have been used for the analysis of FSS, among them, the Wave Method (WCIP). Are various shapes of elements that can be used in FSS, as for example, fractal type, which presents a relative geometric complexity. This work has as main objective to propose a simplification geometric procedure a fractal FSS, from the analysis of influence of details (gaps) of geometry of the same in behavior of the resonance frequency. Complementarily is shown a simple method to adjust the frequency resonance through analysis of a FSS, which uses a square basic cell, in which are inserted two reentrance and dimensions these reentrance are varied, making it possible to adjust the frequency. For this, the structures are analyzed numerically, using WCIP, and later are characterized experimentally comparing the results obtained. For the two cases is evaluated, the influence of electric and magnetic fields, the latter through the electric current density vector. Is realized a bibliographic study about the theme and are presented suggestions for the continuation of this work / As Superf?cies Seletivas de Frequ?ncia (FSS) s?o estruturas peri?dicas em uma ou duas dimens?es que atuam como filtros espaciais, podendo ser formadas por elementos do tipo patches condutores ou aberturas, funcionando como filtros rejeita-faixa ou passa-faixa, respectivamente. O interesse no estudo das FSS tem crescido atrav?s dos anos, pois tais estruturas atendem a requisitos espec?ficos como baixo custo, dimens?es e pesos reduzidos, al?m da possibilidade de se integrar com outros circuitos de micro-ondas. As mais variadas aplica??es para tais estruturas t?m sido investigadas, como por exemplo, radomes, sistemas de antenas para avi?es, filtros eletromagn?ticos para antenas refletoras, estruturas absorvedoras, etc. V?rios m?todos t?m sido utilizados para a an?lise de FSS, dentre eles, o M?todo das Ondas (WCIP). S?o diversas as formas de elementos que podem ser utilizados em FSS, como por exemplo, os do tipo fractal, que apresenta uma relativa complexidade geom?trica. Este trabalho tem como objetivo principal propor um procedimento de simplifica??o geom?trica de uma FSS fractal, a partir da an?lise da influ?ncia dos detalhes (fendas) da geometria da mesma no comportamento da frequ?ncia de resson?ncia. De forma complementar ? mostrado um m?todo simples de ajustar a frequ?ncia de resson?ncia atrav?s da an?lise de uma FSS, que utiliza uma c?lula b?sica retangular, na qual s?o inseridas duas reentr?ncias e as dimens?es dessas reentr?ncias s?o variadas, tornando poss?vel o ajuste da frequ?ncia. Para isso, as estruturas s?o analisadas numericamente, utilizando o WCIP, e posteriormente s?o caracterizadas experimentalmente, comparando-se os resultados obtidos. Para os dois casos ? avaliada, a influ?ncia dos campos el?trico e magn?tico, este ?ltimo atrav?s do vetor densidade de corrente el?trica. ? realizado um estudo bibliogr?fico a cerca do tema e s?o apresentadas sugest?es para a continuidade deste trabalho
18

Avalia??o da capacidade de caminhar do portador de obesidade m?rbida utilizando teste de caminhada de 6 minutos

Lago, Sheyla Thatiane Santos do 30 July 2009 (has links)
Made available in DSpace on 2014-12-17T15:16:06Z (GMT). No. of bitstreams: 1 SheylaTSL.pdf: 1123530 bytes, checksum: 9d193a5e8ae6cbd93482dabd85a41d69 (MD5) Previous issue date: 2009-07-30 / Introduction: The ability to walk is impaired in obese by anthropometric factors (BMI and height), musculoskeletal pain and level of inactivity. Little is known about the influence of body adiposity and the acute response of the cardiovascular system during whole the 6-minute walk test (6mWT). Objective: To evaluate the effect of anthropometric measures (BMI and WHR waist-to-hip ratio), the effort heart and inactivity in ability to walk the morbidly obese. Materials and Methods: a total 36 morbidly obese (36.23 + 11.82 years old, BMI 49.16 kg/m2) were recruited from outpatient department of treatment of obesity and bariatric surgery in University Hospital Onofre Lopes and anthropometric measurements of obesity (BMI and WHR), pulmonary function, pattern habitual physical activity (Baecke Questionnaire) and walking capacity (6mWT). The patient was checking to measure: heart rate (HR), breathing frequency (BF), peripheral oxygen saturation, level of perceived exertion, systemic arterial pressure and duplo-produto (DP), moreover the average speed development and total distance walking. The data were analysed between gender and pattern of body adiposity, measuring the behavior minute by minute of walking. The Pearson and Spearmam correlation coefficients were calculated, and stepwise multiple Regression examined the predictors of walking capacity. All analyses were performed en software Statistic 6.0. Results: 20 obese patients had abdominal adiposity (WHR = 1.01), waist circumference was 135.8 cm in women (25) and 139.8 cm in men (10). Walked to the end of 6mWT 412.43 m, with no differences between gender and adiposity. The total distance walked by obesity alone was explained by BMI (45%), HR in the sixth minute (43%), the Baecke (24%) and fatigue (-23%). 88.6% of obese (31) performed the test above 60% of maximal HR, while the peak HR achieved at 5-minute of 6mWT. Systemic arterial pressure and DP rised after walking, but with no differences between gender and adiposity. Conclusion: The walk of obese didn?t suffers influence of gender or the pattern of body adiposity. The final distance walked is attributed to excess body weight, stress heart, the feeling of effort required by physical activity and level of sedentary to obese. With a minute of walking, the obeses achieved a range of intensity cardiovascular trainning / Introdu??o: A capacidade de caminhar dos obesos ? prejudicada pelo ?ndice de Massa Corporal (IMC), dores osteomioarticulares e n?vel de sedentarismo. Pouco se sabe sobre a influ?ncia do perfil da adiposidade corporal, do g?nero e da resposta aguda do sistema cardiovascular sobre a capacidade de caminhada do obeso. Objetivo: Avaliar o efeito de medidas antropom?tricas (IMC e WHR, waist-to-hip ratio), esfor?o card?aco e sedentarismo sobre a capacidade de caminhada de portadores de obesidade m?rbida. Materiais e M?todos: Entre setembro de 2007 e setembro de 2008, 36 obesos m?rbidos (idade 36,23 + 11,82; IMC 49,16 kg/m2) foram recrutados no ambulat?rio de tratamento da obesidade e cirurgia bari?trica do Hospital Universit?rio Onofre Lopes e avaliados quanto marcadores antropom?tricos de obesidade, fun??o pulmonar, n?vel de atividade f?sica habitual (Question?rio de Baecke) e capacidade de caminhar (TC6M). O paciente era monitorado para verificar: freq??ncia card?aca (FC) e respirat?ria (FR), satura??o perif?rica de oxig?nio, n?vel de esfor?o percebido, press?o arterial sist?mica (PA) e duplo-produto (DP). Durante a caminhada, ainda mensurava-se a velocidade m?dia desenvolvida e dist?ncia total percorrida pelos portadores de obesidade m?rbida. Os dados foram analisados entre os g?neros e o tipo de distribui??o de gordura corporal, avaliando o comportamento das vari?veis a cada minuto caminhado. As correla??es de Pearson e Spearmam foram analisadas. A Regress?o M?ltipla buscou preditores da capacidade de caminhada. Foi utilizado o software Statistic 6.0 para an?lise estat?stica. Resultados: 20 obesos tinham adiposidade abdominal (WHR = 1,01), circunfer?ncia da cintura de 135,8 cm nas mulheres (25) e de 139,8 cm nos homens (10). Durante TC6M, foi caminhada uma dist?ncia de 412,43 m, sem diferen?as entre g?nero ou adiposidade. Essa dist?ncia total percorrida foi explicada isoladamente pelo IMC (45%), FC no sexto minuto (43%), Baecke (24%) e fadiga (-23%). 88,6% dos obesos (31) realizaram o teste acima de 60% da FCM?xima, sendo o pico de FC atingido aos 5 minutos de caminhada. PA e DP aumentaram significativamente com a caminhada, mas sem diferen?as entre g?nero ou adiposidade. Conclus?o: A acaminhada dos obesos m?rbidos n?o sofre influ?ncia do g?nero ou do perfil de adiposidade corporal. A dist?ncia final percorrida ? atribu?da ao excesso de peso corporal, estress card?aco, sensa??o de esfor?o imposta pela caminhada e ao n?vel de sedentarismo pr?vio do obeso. Dentro de 1 minuto de caminhada, os obesos atingem uma zona de treinamento cardiovascular

Page generated in 0.4192 seconds