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  • 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.
291

Etude des effets de programmes d'endurance de haute intensité et de haut volume sur les performances physiques, cognitives ainsi que sur la plasticité musculaire et cérébrale chez le rat sain et ayant subi une ischémie cérébrale / Comparison of high intensity and high volume aerobic training on physical performance, cognition and cerebral and muscular plasticity in healthy rats and after cerebral ischemia

Constans, Annabelle 27 March 2019 (has links)
L’exercice fractionné de haute intensité (HIIT) et continu d’intensité modéré (MOD) représentent les 2 grandes modalités d'endurance. Cependant, leur impact spécifique sur la performance physique et la plasticité cérébrale et musculaire reste controversé du fait de la diversité des protocoles d’exercice proposés chez les sédentaires. Notre 1er axe dégage chez des rats sains l’effet de ces 2 modalités sur la performance physique, la plasticité musculaire et cérébrale sur 8 semaines d’entrainement standardisée dont l'intensité est basées sur le seuil lactique. Nos résultats montrent des gains de performance d’endurance plus rapides et importants suite aux HIIT. La neuroplasticité serait stimulée par les HIIT uniquement et la plasticité musculaire semble spécifique à chacune. L’engouement pour les HIIT se répercute chez les patients subissant un accident vasculaire cérébral où l’efficacité des méthodes d’endurance n’est pas clairement justifiées. Une étude antérieure a montré l’intérêt majeur des HIIT dans la phase aiguë de la pathologie malgré une récupération sensorimotrice incomplète. D’où l’intérêt d’approfondir dans notre second axe l’effet des différentes formes de HIIT (longs et courts) dans la récupération. Nos résultats montrent principalement que ces deux formes de HIIT améliorent la capacité d’endurance et la force de la patte antérieure lésée avec une précocité pour les HIIT longs. Les deux formes de HIIT semblent induire une angiogenèse cérébrale. Néanmoins, ils n’améliorent pas les fonctions sensorimotrices et cognitives. Ainsi, il est nécessaire d’approfondir les répercussions de ces deux entrainements HIIT dans la plasticité musculaire et cérébrale. / Endurance exercise is essential for different reasons in athlete and also in aging and pathological people. Two training modalities were found: high intensity interval training (HIIT) and moderate intensity aerobic training (MOD). However, the specific outcomes of these modalities on physical performance and cerebral and muscular plasticity are controversial because many exercise protocols exist. The 1st study explore the impact of these 2 training on endurance and functional capacity and also on muscular and cerebral molecular modifications throughout 8 weeks in healthy rats. HIIT and MOD programs are work-matched and training intensity are determined thanks to the lactate threshold. Our results show a superior and fast effect on endurance capacity after HIIT compared to MOD. Hippocampal plasticity is stimulated only after HIIT and muscular modifications appear to be specific to each modality. A great interest of HIIT is found in stroke patients for whom evidence of endurance modalities efficiency is still missing. A previous study has shown a beneficial effect of HIIT in the acute phase of stroke despite incomplete sensorimotor recuperation. Hence, the interest to deepen in second part of this manuscript the impact of two HIIT modalities (short and long) in recovery optimisation. Our results show that 2 HIIT strongly improve endurance performance and strength of injured paw with a fast effect for long HIIT. The 2 modalities seem to induce cerebral angiogenesis. However, these 2 training do not increase sensorimotor and cognitive functions. In perspective, it appears necessary to develop muscular and cerebral outcomes induced by these 2 HIIT modalities.
292

Quantification of Precipitation Asymmetries in Tropical Cyclones and Their Relationship to Storm Intensity Changes Using TRMM Data

Pei, Yongxian 12 October 2017 (has links)
The climatology of precipitation asymmetries in Tropical Cyclones (TCs) and their relationship to TC intensity changes using 16 years of data from the Tropical Rainfall Measuring Mission (TRMM) satellite. TC Inner core precipitation asymmetries were quantified using the Fourier wavenumber decomposition method upon the pixel level data of 3,542 TRMM TMI overpasses. Composites of wavenumber–1 and wavenumber 1–6 total precipitation asymmetries were constructed to show the distribution pattern under different storm motion speed, vertical wind shear and the combined effects of varying vertical wind shear and storm motion. Results indicate that motion–relative total precipitation asymmetry is located down–motion. The phase of motion–relative maximum asymmetry shifts cyclonically by adding the wavenumber–2–6 asymmetry to wavenumber–1. Shear is more dominant than motion on the distribution of precipitation asymmetry. The analysis of combined effects of motion and shear shows when shear is weak, and shear is to the left of motion, the precipitation asymmetry is explained more by storm motion. The main contributor to the general asymmetry pattern is from the moderate and heavy precipitation. The wavenumber 2–6 energy localizes the maximum heavy precipitation asymmetry. The quantified wavenumber 1–6 asymmetries is also applied to differentiate between different intensity change categories and the asymmetry evolution of a rapidly intensifying storm. The precipitation asymmetry properties of rapid intensification (RI) and non–RI storms are examined. The dataset of 2,186 global tropical storms through category 2 hurricanes is divided by future 24–h intensity change and includes storms with at least moderately favorable environmental conditions. The normalized wavenumber 1–6 asymmetries, indicates quantitatively that the lower asymmetry of precipitation is most strongly correlated with future intensity change. The precipitation field of non–RI storms are more asymmetric than RI storms. The 595 sampled overpasses are classified into 14 categories in the timeline of an RI event from 48 hours before RI until RI ends. The decrease of normalized wavenumber 1–6 asymmetries in the inner core region of all four types of precipitation several hours before RI onset was quantitatively demonstrated to be critical for TC RI.
293

Relationships Between Felt Intensity And Recorded Ground Motion Parameters For Turkey

Bilal, Mustafa 01 January 2013 (has links) (PDF)
Earthquakes are among natural disasters with significant damage potential / however it is possible to reduce the losses by taking several remedies. Reduction of seismic losses starts with identifying and estimating the expected damage to some accuracy. Since both the design styles and the construction defects exhibit mostly local properties all over the world, damage estimations should be performed at regional levels. Another important issue in disaster mitigation is to determine a robust measure of ground motion intensity parameters. As of now, well-built correlations between shaking intensity and instrumental ground motion parameters are not yet studied in detail for Turkish data. In the first part of this thesis, regional empirical Damage Probability Matrices (DPMs) are formed for Turkey. As the input data, the detailed damage database of the 17 August 1999 Kocaeli earthquake (Mw=7.4) is used. The damage probability matrices are derived for Sakarya, Bolu and Kocaeli, for both reinforced concrete and masonry buildings. Results are compared with previous similar studies and the differences are discussed. After validation with future data, these DPMs can be used in the calculation of earthquake insurance premiums. In the second part of this thesis, two relationships between the felt-intensity and peak ground motion parameters are generated using linear least-squares regression technique. The first one correlates Modified Mercalli Intensity (MMI) to Peak Ground Acceleration (PGA) whereas the latter one does the same for Peak Ground Velocity (PGV). Old damage reports and isoseismal maps are employed for deriving 92 data pairs of MMI, PGA and PGV used in the regression analyses. These local relationships can be used in the future for ShakeMap applications in rapid response and disaster management activities.
294

Pramoninio dažnio elektromagnetinių laukų tyrimas / Research of industrial frequency electromagnetic fields

Morozionkov, Jevgenij 13 June 2006 (has links)
Literary review, according to theoretical and experimental researches, it was noticed that electromagnetic fields of industrial frequency influence the human and environment. Power force of low frequentative electromagnetic beaming is little. However electromagnetic beams of these low frequentative domains have clearly expressed electrical and magnetic fields which affect the separate parts of human body. The most sensitive parts to the effect of electromagnetic fields are the nervous system and the neuroendocrine system. The biggest sources of electromagnetic fields are the domestic appliances, the installations of electricity transmission, transference and the distributing installations in residential and working places. Electromagnetic fields are generated with electric installations and spread in space by 1/r3; 1/r2 and 1/r law. It is typical of the value change of electric and magnetic fields. Parameter value of electromagnetic fields is solved with electricity installations tension, stream and the location of analyzed point in point of installations. Summing up the wide energetic net of our country, the fact of usable electric installations (which create electromagnetic fields in residential and working places) assume the marked social signification, there is posed the opportunity to forecast the available values of low electromagnetic fields effect, and to forecast means to remove it.
295

Cancer treatment optimization

Cha, Kyungduck 01 April 2008 (has links)
This dissertation investigates optimization approaches applied to radiation therapy in cancer treatment. Since cancerous cells are surrounded by critical organs and normal tissues, there is conflicting objectives in the treatment design of providing sufficient radiation dose to tumor region, while avoiding normal healthy cells. In general, the goal of radiation therapy is to conform the spatial distribution of the prescribed dose to the tumor volume while minimizing the dose to the surrounding normal structures. A recent advanced technology, using multi-leaf collimator integrated into linear accelerator, provides much better opportunities to achieve this goal: the radiotherapy based on non-uniform radiation beams intensities is called Intensity-Modulated Radiation Therapy. My dissertation research offers a quadratic mixed integer programming approach to determine optimal beam orientations and beamlets intensity simultaneously. The problems generated from real patient cases are large-scale dense instances due to the physics of dose contributions from beamlets to volume elements. The research highlights computational techniques to improve solution times for these intractable instances. Furthermore, results from this research will provide plans that are clinically acceptable and superior in plan quality, thus directly improve the curity rate and lower the normal tissue complication for cancer patients.
296

Intensidade acústica útil: um novo método para identificação de regiões radiantes em superfícies com geometrias arbitrárias / Useful acoustic intensity: a new method for the identification of radiant regions on surfaces with arbitrary geometries

Cleber de Almeida Corrêa Junior 16 March 2012 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Neste trabalho é descrita a teoria necessária para a obtenção da grandeza denominada intensidade supersônica, a qual tem por objetivo identificar as regiões de uma fonte de ruído que efetivamente contribuem para a potência sonora, filtrando, consequentemente, a parcela referente às ondas sonoras recirculantes e evanescentes. É apresentada a abordagem de Fourier para a obtenção da intensidade supersônica em fontes com geometrias separáveis e a formulação numérica existente para a obtenção de um equivalente à intensidade supersônica em fontes sonoras com geometrias arbitrárias. Este trabalho apresenta como principal contribuição original, uma técnica para o cálculo de um equivalente à intensidade supersônica, denominado aqui de intensidade acústica útil, capaz de identificar as regiões de uma superfície vibrante de geometria arbitrária que efetivamente contribuem para a potência sonora que será radiada. Ao contrário da formulação numérica existente, o modelo proposto é mais direto, totalmente formulado na superfície vibrante, onde a potência sonora é obtida através de um operador (uma matriz) que relaciona a potência sonora radiada com a distribuição de velocidade normal à superfície vibrante, obtida com o uso do método de elementos finitos. Tal operador, chamado aqui de operador de potência, é Hermitiano, fato crucial para a obtenção da intensidade acússtica útil, após a aplicação da decomposição em autovalores e autovetores no operador de potência, e do critério de truncamento proposto. Exemplos de aplicações da intensidade acústica útil em superfícies vibrantes com a geometria de uma placa, de um cilindro com tampas e de um silenciador automotivo são apresentados, e os resultados são comparados com os obtidos via intensidade supersônica (placa) e via técnica numérica existente (cilindro), evidenciando que a intensidade acústica útil traz, como benefício adicional, uma redução em relação ao tempo computacional quando comparada com a técnica numérica existente. / This work describes the theory necessary to obtain the greatness called supersonic intensity, which aims to identify the regions of a sound source that effectively contribute to the sound power radiated, filtering recirculating and evanescent sound waves. The Fourier approach to obtain the supersonic intensity in sources having separable geometries, and the existent numerical formulation to obtain an equivalent to supersonic intensity on noise sources with arbitrary geometry. This work presents a new numeric technique for the computation of the numerical equivalent to the supersonic acoustic intensity. The technique provides the identification of the regions of a noise source with arbitrary geometry that effectively contribute to the sound power radiated to the far field by filtering recirculating and evanescent sound waves. The proposed technique is entirely formulated on the vibrating surface. The acoustic power radiated is obtained through a numerical operator that relates it with the distribution of superficial normal velocity, which is obtained by the boundary element method. Such power operator, possesses the property of being Hermitian. The advantage of this characteristic is that their eigenvalues are real and their eigenvectors form an orthonormal set for the velocity distribution. It is applied to the power operator the decomposition in eigenvalues and eigenvectors, becoming possible to compute the numerical equivalent to the supersonic intensity, called here useful intensity, after applying a cutoff criterion to remove the non propagating components. Some numerical tests confirming the effectiveness of the convergence criterions are presented. Examples of the application of the useful intensity technique in vibrating surfaces such as a plate, a cylinder with flat caps and an automotive muffler are presented and the numerical results are discussed, showing that the useful intensity brings, as additional benefit, a reduction of the computational effort, when compared to existent numerical technique.
297

Intensidade acústica útil: um novo método para identificação de regiões radiantes em superfícies com geometrias arbitrárias / Useful acoustic intensity: a new method for the identification of radiant regions on surfaces with arbitrary geometries

Cleber de Almeida Corrêa Junior 16 March 2012 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Neste trabalho é descrita a teoria necessária para a obtenção da grandeza denominada intensidade supersônica, a qual tem por objetivo identificar as regiões de uma fonte de ruído que efetivamente contribuem para a potência sonora, filtrando, consequentemente, a parcela referente às ondas sonoras recirculantes e evanescentes. É apresentada a abordagem de Fourier para a obtenção da intensidade supersônica em fontes com geometrias separáveis e a formulação numérica existente para a obtenção de um equivalente à intensidade supersônica em fontes sonoras com geometrias arbitrárias. Este trabalho apresenta como principal contribuição original, uma técnica para o cálculo de um equivalente à intensidade supersônica, denominado aqui de intensidade acústica útil, capaz de identificar as regiões de uma superfície vibrante de geometria arbitrária que efetivamente contribuem para a potência sonora que será radiada. Ao contrário da formulação numérica existente, o modelo proposto é mais direto, totalmente formulado na superfície vibrante, onde a potência sonora é obtida através de um operador (uma matriz) que relaciona a potência sonora radiada com a distribuição de velocidade normal à superfície vibrante, obtida com o uso do método de elementos finitos. Tal operador, chamado aqui de operador de potência, é Hermitiano, fato crucial para a obtenção da intensidade acússtica útil, após a aplicação da decomposição em autovalores e autovetores no operador de potência, e do critério de truncamento proposto. Exemplos de aplicações da intensidade acústica útil em superfícies vibrantes com a geometria de uma placa, de um cilindro com tampas e de um silenciador automotivo são apresentados, e os resultados são comparados com os obtidos via intensidade supersônica (placa) e via técnica numérica existente (cilindro), evidenciando que a intensidade acústica útil traz, como benefício adicional, uma redução em relação ao tempo computacional quando comparada com a técnica numérica existente. / This work describes the theory necessary to obtain the greatness called supersonic intensity, which aims to identify the regions of a sound source that effectively contribute to the sound power radiated, filtering recirculating and evanescent sound waves. The Fourier approach to obtain the supersonic intensity in sources having separable geometries, and the existent numerical formulation to obtain an equivalent to supersonic intensity on noise sources with arbitrary geometry. This work presents a new numeric technique for the computation of the numerical equivalent to the supersonic acoustic intensity. The technique provides the identification of the regions of a noise source with arbitrary geometry that effectively contribute to the sound power radiated to the far field by filtering recirculating and evanescent sound waves. The proposed technique is entirely formulated on the vibrating surface. The acoustic power radiated is obtained through a numerical operator that relates it with the distribution of superficial normal velocity, which is obtained by the boundary element method. Such power operator, possesses the property of being Hermitian. The advantage of this characteristic is that their eigenvalues are real and their eigenvectors form an orthonormal set for the velocity distribution. It is applied to the power operator the decomposition in eigenvalues and eigenvectors, becoming possible to compute the numerical equivalent to the supersonic intensity, called here useful intensity, after applying a cutoff criterion to remove the non propagating components. Some numerical tests confirming the effectiveness of the convergence criterions are presented. Examples of the application of the useful intensity technique in vibrating surfaces such as a plate, a cylinder with flat caps and an automotive muffler are presented and the numerical results are discussed, showing that the useful intensity brings, as additional benefit, a reduction of the computational effort, when compared to existent numerical technique.
298

Estudo comparativo dos efeitos do ultra-som e do laser de baixa intensidade no reparo ósseo de tíbia de rato / Comparative study of ultra-sound and low intensity laser therapy effects on bone healing in rats tibia

Ana Paula Rebucci Lirani 24 March 2004 (has links)
Vários estudos têm avaliado os efeitos do ultra-som e da radiação laser de baixa intensidade separadamente no reparo ósseo. No entanto, são escassas as comparações entre estas duas modalidades terapêuticas. Este estudo teve por objetivo avaliar e comparar, através de análise histomorfométrica e ensaio mecânico de flexão em três pontos, as conseqüências que estes agentes físicos podem trazer ao reparo do tecido ósseo em osteotomias transversais experimentais em tíbias de ratos. Foram utilizados 48 ratos com fratura cirúrgica unilateral parcial do terço superior de tíbia. Os animais foram divididos em três grupos de 16 animais. Em um grupo, o membro fraturado foi tratado com ultra-som pulsado de baixa intensidade (freqüência de 1,5 MHz, ciclo de trabalho 1:4, intensidade SATA 30 mW/centímetro quadrado) em sessões de 20 minutos, 5 vezes por semana, em 12 dias de tratamento. Em um segundo grupo, o membro fraturado foi tratado com laser As-Ga-Al (112,5 J/centímetro quadrado, 780 nm, 30 mW) em sessões de 2,5 minutos, 5 vezes por semana, em 12 dias de tratamento. O terceiro grupo serviu de controle, sendo submetido à mesma cirurgia na tíbia direita mas não recebeu qualquer tratamento. No ensaio mecânico, a carga no limite máximo suportada pelo grupo tratado com laser foi significantemente maior (p < 0,05) que os grupos tratado com ultra-som e controle. Na análise histomorfométrica, o grupo tratado com laser apresentou significância estatística quanto ao número e superfície de osteoblastos e volume e superfície de osteóide e o grupo ultra-som obteve significância para as superfícies de reabsorção e de osteoclastos. Pode-se concluir que o ultra-som acelerou o reparo ósseo (em relação ao grupo controle) por viabilizar mais rapidamente a fase de reabsorção, enquanto que a terapia laser foi capaz de acelerar ainda mais este processo por já promover predomínio de formação óssea no décimo nono dia pós-cirúrgico no modelo experimental utilizado neste estudo / Many studies have assessed the effects of ultra-sound and low intensity laser therapy separatedly in bone repair. However, the comparison between these two therapeutic modalities is rare. The objective of this study was to verify and compare, through histomorphometrical analysis and a three-point bending test, the consequences of these physical agents on bone healing in animals. 48 male Wistar rats were used with tibial bone partial osteotomy, divided into 3 groups of 16. In one group, rats had their fractured limb treated with GaAIAs laser (780 nm, 30 mW, 112,5 J/square contimeter) in 12 five times-a-week sections. In another group, rats were treated with low intensity pulsed ultra-sound (1,5 MHz, 30 mW/square centimeter) in 12 five times-a-week sections too. In a third group, animals were taken as control, being submitted to the same osteotomy but receiving no treatment. After 19 days the tibias were extracted and half of them were submitted to a three-point bending test and the other half to histomorphometric analysis. During the bending test, the maximum load at failure of the tibia in the laser group was significantly higher (p<0.05). Histomorphometry showed statistical significance in osteoblasts number and surface and osteoid volume and surface for the laser group, and eroded and osteoclasts surfaces for the ultra-sound group. Ultra-sound was able to enhance bone healing (compared to control group) by speeding up the reabsorption phase, while low intensity laser therapy could accelerate this process even more by promoting mostly new bone formation 19 days after osteotomy in this experimental model
299

Měření relativní variance optické intenzity / Measurement of relative variance of optical intensity

Vaníček, Jakub January 2011 (has links)
The intention of this master‘s thesis is the measurment of relative variance of optical intensity. In the first place, I have been studied Kolmogorov cascade theory of turbulence and relative variance of optical intensity . In addition, I have been deal with turbulent cells, Gaussian beam, Top Hat beam and influence of the atmospheric turbulences on the intensity profile of the laser beam. Lastly I have been measured determine influence of the atmospheric turbulences on the intensity profile of the laser beam and I have been calculated relative variance of optical intensity. I have suggested the optimum beam profile in the turbulent atmosphere from acquired data.
300

Simulace LED náhrad v reálných podmínkách / Simulation of LED retrofits under operational conditions

Tomeš, Martin January 2014 (has links)
This Master’s Thesis on Simulation of LED retrofits under operational conditions is divided into theoretical and practical part. Theoretical part in the introductory section deals with the concepts of lighting technology and presents some electric light sources, such as classic bulbs, halogen bulbs, linear and compact fluorescent lamps. It also describes the principle of electroluminescent light sources (LED), which discusses principles of yielding a white light, the main advantages of LED etc. The reader is familiar with the issue of compensation the linear fluorescent lamps tubular LED source and with the work environment programme ReluxPro that is used for design of the lighting system. Practical part of the thesis is divided into two chapters. In the first chapter, measured linear fluorescent lamps and LED modules for the light-technical parameters, luminous intensity, radiation spectrum and settling time of light sources are evaluated and compared. The second chapter is solved by using ReluxPro, which explores the impact on the lighting and the brightness of the room layout SA 5.10 while using various light sources. In conclusion, there is an economic aspect of linear fluorescent lamps and LED modules analyzed. Results from the program ReluxPro are continuously compared with real measured values.

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