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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.
31

Análise do grau de lesão obstrutiva coronária e sua correspondente parede miocárdica como fatores preditivos de perviedade e remodelamento da artéria radial na revascularização do miocárdio / Analysis of coronary obstruction and irrigated myocardial wall as predictive factors for patency and remodeling of radial artery grafts in coronary artery bypass surgery

Carneiro, Luciano Jannuzzi 17 February 2009 (has links)
A artéria radial (AR) constitui valiosa opção de enxerto na revascularização do miocárdio (RM), desde a retomada de seu uso, nos anos 1990. O objetivo deste estudo foi avaliar perviedade e remodelamento dos enxertos de AR e sua relação com lesão obstrutiva pré-operatória e parede miocárdica revascularizada, observando-se também os enxertos de artéria torácica interna (ATI). CASUÍSTICA E MÉTODO: Entre 1994 e 2007, 3.964 pacientes foram operados com uso da AR, no InCor/HCFMUSP. Foram selecionados os reestudos angiográficos (12 meses) de 100 pacientes, sendo 11 deles reestudados em duas épocas diferentes. Em 92 pacientes foi utilizada a ATI. Foram determinados os diâmetros médios de AR e ATI, através do software CASS-II®. RESULTADOS: O tempo médio de reestudo foi de 70,53 ±33,18 meses. Em 82 casos (82,0%), a AR revascularizou uma única coronária, mais freqüentemente (50,83%) os ramos marginal esquerdo (ME) ou ventricular posterior (VP/CX). As obstruções pré-operatórias entre 90 e 99% foram as mais prevalentes (39,0%). A perviedade observada foi de 80 casos para AR (80,0%) e 80 para ATIE (86,96%). Houve correlação entre as maiores obstruções pré-operatórias e maior perviedade da AR (p=0,024). Os diâmetros médios dos enxertos foram de 2,302mm ±0,479 (AR) e 2,262mm ±0,409 (ATI). Observaram-se AR maiores do que a média (>2,30mm) nas obstruções pré-operatórias de 100%, em comparação com as demais (p=0,017). As AR que revascularizaram a parede lateral apresentaram os maiores diâmetros, em comparação às demais (p=0,04). Nos 11 pacientes com 2 reestudos, os diâmetros médios das AR foram de: 2,482mm ±0,424 (primeiro reestudo) e 2,599mm ±0,532 (segundo reestudo)(p=n/s). Para as ATIE, observaram-se: 2,308mm ±0,459 (primeiro reestudo) e 2,326mm ±0,531 (segundo reestudo) (p=n/s). No segundo reestudo, observou-se maior número de AR com diâmetros maiores, relacionados às obstruções entre 90-100% (p=0,013). A parede miocárdica revascularizada não interferiu nos diâmetros dos enxertos. CONCLUSÕES: A obstrução pré-operatória interfere na perviedade e nos diâmetros dos enxertos de AR, especialmente nas obstruções de 90% ou mais. A parede miocárdica revascularizada não interfere na perviedade da AR, porém interfere nos diâmetros dos enxertos. Foi observado remodelamento dos enxertos de AR, estando as obstruções mais graves relacionadas aos maiores aumentos de diâmetros dos enxertos comportamento semelhante às ATI. / The radial artery (RA) is an invaluable option for coronary artery bypass grafting (CABG), since its re-introduction in the late 1990 s.The objective of this study was to assess patency and remodeling of RA grafts regarding the interference of pre-operative coronary obstruction and grafted myocardial wall, also observing the internal thoracic artery grafts (ITA). METHODS: Between 1994 and 2007, 3,964 patients were operated with RA grafts, at Heart Institute, University of São Paulo, Brazil. Post-operative coronary angiographies (12 months)of 100 patients were obtained, including 11 patients with two post-op exams, at different periods. In 92 patients the ITA was also used.The grafts medium diameters were obtained using the CASS-II® software. RESULTS: Mean time of post-op angiography was 70,53 ±33,18 months. In 82 cases (82,0%) the RA grafted a single coronary, more frequently (50,83%) the left marginal (LM) or posterior ventricular (PV) branches. Pre-op obstructions between 90 and 99% were more prevalent (39,0%). Patency was of 80 cases for the RA (80,0%) and 80 cases for the ATI grafts (86,96%). There was a correlation between more severe pre-op obstructions and greater patency of the RA grafts (p=0,024). The mean diameters were 2,302mm ±0,479 (RA) and 2,262mm ±0,409 (ITA). RA diameters were above the mean value (>2,30mm) in pre-op obstructions of 100%, compared to the rest (p=0,017). The RA grafting the lateral wall showed the larger diameters, compared to the rest (p=0,04). For the 11 patients with 2 post-op angiographies, mean diameters of RA grafts were: 2,482mm ±0,424 (first) and 2,599mm ±0,532 (second)(p=n/s). For ITA grafts, mean diameters were: 2,308mm ±0,459 (first) and 2,326mm ±0,531 (second)(p=n/s). For the second angiographies, RA grafts exhibited larger diameters, related to pre-op obstructions between 90 and 100% (p=0,013). The grafted myocardial wall showed no interference with graft diameter. CONCLUSIONS: Pre-op coronary obstruction interferes in patency and diameters of RA grafts, more evidently for obstructions of 90% or greater. The grafted myocardial wall does not interfere with RA patency, although it does interfere with graft diameter. Remodeling was observed in RA grafts, correlating greater pre-op coronary obstructions and more evident increase in graft diameter similarly to the ITA grafts.
32

Aplicación del programa radial mi novela favorita en el aprendizaje de las capacidades comunicativas en alumnos de educación secundaria

Leiva Bazán, Zulema Daria January 2015 (has links)
La presente investigación se enmarca en el programa de Licenciatura de Comunicación Social en la Universidad Nacional Mayor de San Marcos, impartido por la Facultad de Letras y Ciencias Humanas de esta casa de estudios y pretende estudiar los efectos de programa radial Mi novela favorita en las capacidades comunicativas de los alumnos de la Institución Educativa Privada América International School de Lima. Un punto de partida para la realización de este estudio es el interés por conocer sobre las adaptaciones radiales y otro es la preocupación por el desarrollo de las capacidades comunicativas en los alumnos de secundaria. Diversos autores destacan la presencia de la literatura en la radio ya sea en programas educativos o en adaptaciones radiales, como en el caso a estudiar. Se trata del programa Mi novela favorita, producida por Radio Programas del Perú, con un equipo de primer nivel, además con la selección y presentación de nuestro Premio Nobel Mario Vargas Llosa. En otras investigaciones se han hecho referencia a las adaptaciones radiales, pero en este caso existe la particularidad de ser un proyecto netamente peruano y con un ambicioso objetivo: educar entreteniendo. El aprendizaje de las capacidades comunicativas de los estudiantes en nuestro país se encuentran disminuidas, diversos estudios así lo sustentan, y se dice también que la falta de estas capacidades mermará, en un futuro, el desarrollo integral del estudiante. También existe la necesidad de acercar al público, en especial al alumno, a la literatura, de la que progresivamente se ha ido alejando. Esta investigación consta de cuatro capítulos, en el primero se plantea el problema, para ello se realiza un diagnóstico del fenómeno a estudiar, dando por efecto la formulación del problema; a su vez, se explican la importancia, los alcances de la investigación y sus limitaciones. El segundo capítulo contiene el marco teórico, donde se presentan los antecedentes de la investigación, los fundamentos teóricos, las concepciones y enfoques sobre las variables y la definición de términos básicos. En el tercer capítulo se fundamentan y formulan las hipótesis; se identifica, clasifica y operacionaliza las variables. En el cuarto capítulo se enuncia la metodología el presente estudio, se trata de una investigación aplicada, el método es el deductivo-inductivo, el diseño de investigación es el cuasiexperimental – explicativo. Asimismo nos referimos a la población, muestra y los instrumentos de recolección de datos. El quinto capítulo desarrolla la estrategia utilizada para la prueba de hipótesis, se expone la presentación, análisis e interpretación de los datos a través de gráficos y datos comparativos entre el grupo experimental y el grupo control; así también, el proceso de prueba de hipótesis, la discusión de los resultados y la adopción de las decisiones; también se añade una interpretación cualitativa, realizada a través de una guía de observación sobre las capacidades comunicativas de los alumnos que corresponden a la muestra. Finalmente se presentan las conclusiones y se sugieren algunas recomendaciones de la investigación, acompañadas de las referencias bibliográficas y los anexos que ilustran y ayudan a su mejor comprensión. Se adjunta la matriz de consistencia, los instrumentos de recolección de datos entre ellos el resumen de la validación, las tablas utilizadas y la reseña histórica del centro educativo donde se realizó el estudio. / Tesis
33

Radial Solutions to an Elliptic Boundary Valued Problem

Ventura, Ivan 01 May 2007 (has links)
In this paper we prove that div(|x|β∇u)+|x|αf(u)=0, inB u = 0 on ∂B has infinitely many solutions when f is superlinear and grows subcritically for u ≥ 0 and up to critically for u less than 0 with 10, 13 N+β−2 N+β−2 We make extensive use of Pohozaev identities and phase plane and energy arguments.
34

Optical considerations in solar concentrating systems

Buie, Damien Charles William January 2003 (has links)
To optimise the performance of concentrating solar power systems, a detailed knowledge of the resultant flux distribution in the imaging plane is required. To achieve this, an accurate model of the direct solar beam impinging on the concentrator is essential. This thesis presents an empirical model of the terrestrial solar distribution that has both a high-correlation to observed data and an invariance to a change in location. The model is based on the amount of circumsolar radiation in the direct beam and takes into account the small variations that are due to atmospheric scattering. A modelling framework is developed to simulate the flux distribution in the imaging plane of a generic solar concentrating system. Algorithms are developed to include the following: the spatial solar energy distribution; the systemic effect of reflecting that distribution off a non-ideal mirrored surface; the spectral energy distribution; the transmission, absorption and reflection characteristics of optical thin films; and the coordinates of the solar vector. The framework is then used to investigate the performance of anti-reflection coatings on silicon substrates and the performance of linear Fresnel systems. Combined, these algorithms and simulation tools can be applied to create comprehensive optical models of solar concentrating systems.
35

Radial Bases and Ill-Posed Problems

Chen, Ho-Pu 15 August 2006 (has links)
RBFs are useful in scientific computing. In this thesis, we are interested in the positions of collocation points and RBF centers which causes the matrix for RBF interpolation singular and ill-conditioned. We explore the best bases by minimizing error function in supremum norm and root mean squares. We also use radial basis function to interpolate shifted data and find the best basis in certain sense. In the second part, we solve ill-posed problems by radial basis collocation method with different radial basis functions and various number of bases. If the solution is not unique, then the numerical solutions are different for different bases. To construct all the solutions, we can choose one approximation solution and add the linear combinations of the difference functions for various bases. If the solution does not exist, we show the numerical solution always fail to satisfy the origin equation.
36

Pusiau reliatyvistinės radialinės Šriodingerio lygties su kuloniniu potencialu sprendinių struktūra / The structure of the solutions of semi-relativistic radial Shrodinger equation with coulomb potential

Blonskytė, Donata 03 September 2010 (has links)
Ištirta ketvirtos eilės paprastoji diferencialinė lygtis, sukonstruoti jos sprendiniai absoliučiai ir tolygiai konverguojančiomis laipsninėmis eilutėmis. / The fourth succession’s ordinary differential equation was explored, its assertions were constructed in to absolutely and gradually convergent degree rows.
37

Radial Deformation Acuity In Children With Amblyopia

Betts, Michael John 25 March 2013 (has links)
Purpose: To examine the relationship between visual acuity (VA) and radial deformation acuity (RDA) in children 6 to 12 years of age with amblyopia. Methods: RDA was measured in 35 participants with the Manchester RDA charts. VA was measured with the Early Treatment Diabetic Retinopathy Research Study (ETDRS) chart. Results: Median VA in non-amblyopic and amblyopic eyes was 0.04 logMAR (IQF -0.06 – 0.12) and 0.24 (IQF 0.12 – 0.04), respectively (Wilcoxon Signed Ranks test, z = -5.07, p < 0.001). Median RDA in non-amblyopic and amblyopic eyes was 2.73 log (IQF 2.53 – 2.87) and 2.63 log (IQF 2.53 – 2.77), respectively (Wilcoxon, z = -2.56, p < 0.05). Spearman correlation suggested that the amblyopic deficits in VA and RDA were related, r = -0.42, p < 0.05. Conclusion: A deficit in RDA was present in most children with amblyopia. A moderate relationship was noted between the amblyopic deficits found in VA and RDA.
38

A Study of Southern Spectroscopic Binaries

Thompson, Vincent Brent January 2009 (has links)
The study of spectroscopic binaries is by no means a new area of study. The Doppler shifting of spectral lines as the stars orbit around each other is now able to be measured very precisely. Binary stars give a reliable means of determining stellar parameters such as the mass. A star's mass is one of the most dominant factors in determining its evolution. Stars for study in this thesis were selected from SB9 (the ninth catalogue of spectroscopic binaries). They were chosen on criteria such as apparent visual magnitude, orbital period, orbital solution grade, equatorial velocity and position. Only stars with poor to average orbital solutions were chosen as it is these orbits which need the most work done. In total 6 spectroscopic binary systems were chosen for study in this thesis. Four single lined spectroscopic binaries (HD 70958, HD 110318, HD 122223 and HD 141544) and two double line spectroscopic binaries (HD 110317 and HD 148704). Unfortunate observing conditions meant that adequate phase coverage of HD 110317 and HD 110318 was not achieved. Adequate phase coverage of the star HD 122223 was also not achieved but this is likely a result of the period being about three years and not about 207 days as quoted in the catalogue. Observations were carried out with the HERCULES spectrograph and the 1-metre McLellan telescope at the Mt John University Observatory from December 2007 until September 2008. Radial velocities were than measured from these spectra with HRSP3 and then orbital solutions were derived. Orbital solutions have been derived for the single-lined systems HD 141544 and HD 70958. The precision of HD 141544 was much better than HD 70598. This is because HD 70958 is complicated by differential rotation and possible chromospheric activity. The orbital solution of the double lined system HD 148704 was obtained by using CARTopt and not TODCOR as is common, with good results. HD 122223 is included even though only six spectra were obtained as it will be evident that the current orbital solution should be rejected in favour of the previous solution obtained in 1936 by Christie. Although the amount of data was not as large as was hoped, significant improvements of the orbital solutions were obtained. The secondary component of HD 148704 had only previously being detected in a very few spectra but now has a good orbital solution. Errors on all parameters have been decreased and tighter limits have been placed on the secondary components of the single lined systems. The mass ratio of the components of HD 148704 was also determined very accurately and calculation of the inclination from photometry may allow accurate masses to be determined.
39

Safety and efficacy of radial artery conduits for coronary artery bypass surgery

Ruengsakulrach, Permyos Unknown Date (has links) (PDF)
Coronary artery bypass grafting (CABG) is the most common cardiac surgical operation performed in western countries, and is also increasingly being performed in developing countries. However the long-term results of CABG using the saphenous vein graft have not been satisfactory. Surgeons have therefore been seeking a better conduit. The radial artery (RA) is a potentially suitable alternative conduit and has to date provided good early results. This thesis investigates the utility of the RA as a coronary artery bypass graft from a number of perspectives. It demonstrates the safety of RA harvesting by examining hand collateral circulation using anatomical dissection, physical examination using the modified Allen test, measuring digital blood pressure, and examining the flow velocity in the digital artery using Doppler ultrasound. Anatomical examinations revealed consistent continuity between the RA and ulnar artery in the hand through either superficial or deep palmar arches. The modified Allen test was found to be useful as a screening test compared with the Doppler dynamic test and digital blood pressure index. A histological comparison was made between pre-existing intimal disease in the RA compared with that in the standard conduit the internal thoracic artery (ITA). The RA showed a higher prevalence and degree of intimal disease than ITA. Risk factors for intimal hyperplasia in the RA were age, diabetes, smoking and peripheral vascular disease. The only predictor for medial calcification was age. (For complete abstract open document)
40

A Study of Southern Spectroscopic Binaries

Thompson, Vincent Brent January 2009 (has links)
The study of spectroscopic binaries is by no means a new area of study. The Doppler shifting of spectral lines as the stars orbit around each other is now able to be measured very precisely. Binary stars give a reliable means of determining stellar parameters such as the mass. A star's mass is one of the most dominant factors in determining its evolution. Stars for study in this thesis were selected from SB9 (the ninth catalogue of spectroscopic binaries). They were chosen on criteria such as apparent visual magnitude, orbital period, orbital solution grade, equatorial velocity and position. Only stars with poor to average orbital solutions were chosen as it is these orbits which need the most work done. In total 6 spectroscopic binary systems were chosen for study in this thesis. Four single lined spectroscopic binaries (HD 70958, HD 110318, HD 122223 and HD 141544) and two double line spectroscopic binaries (HD 110317 and HD 148704). Unfortunate observing conditions meant that adequate phase coverage of HD 110317 and HD 110318 was not achieved. Adequate phase coverage of the star HD 122223 was also not achieved but this is likely a result of the period being about three years and not about 207 days as quoted in the catalogue. Observations were carried out with the HERCULES spectrograph and the 1-metre McLellan telescope at the Mt John University Observatory from December 2007 until September 2008. Radial velocities were than measured from these spectra with HRSP3 and then orbital solutions were derived. Orbital solutions have been derived for the single-lined systems HD 141544 and HD 70958. The precision of HD 141544 was much better than HD 70598. This is because HD 70958 is complicated by differential rotation and possible chromospheric activity. The orbital solution of the double lined system HD 148704 was obtained by using CARTopt and not TODCOR as is common, with good results. HD 122223 is included even though only six spectra were obtained as it will be evident that the current orbital solution should be rejected in favour of the previous solution obtained in 1936 by Christie. Although the amount of data was not as large as was hoped, significant improvements of the orbital solutions were obtained. The secondary component of HD 148704 had only previously being detected in a very few spectra but now has a good orbital solution. Errors on all parameters have been decreased and tighter limits have been placed on the secondary components of the single lined systems. The mass ratio of the components of HD 148704 was also determined very accurately and calculation of the inclination from photometry may allow accurate masses to be determined.

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