875 resultados para Image acquisition and representation
Resumo:
Background: The physical characteristic of protons is that they deliver most of their radiation dose to the target volume and deliver no dose to the normal tissue distal to the tumor. Previously, numerous studies have shown unique advantages of proton therapy over intensity-modulated radiation therapy (IMRT) in conforming dose to the tumor and sparing dose to the surrounding normal tissues and the critical structures in many clinical sites. However, proton therapy is known to be more sensitive to treatment uncertainties such as inter- and intra-fractional variations in patient anatomy. To date, no study has clearly demonstrated the effectiveness of proton therapy compared with the conventional IMRT under the consideration of both respiratory motion and tumor shrinkage in non-small cell lung cancer (NSCLC) patients. Purpose: This thesis investigated two questions for establishing a clinically relevant comparison of the two different modalities (IMRT and proton therapy). The first question was whether or not there are any differences in tumor shrinkage between patients randomized to IMRT versus passively scattered proton therapy (PSPT). Tumor shrinkage is considered a standard measure of radiation therapy response that has been widely used to gauge a short-term progression of radiation therapy. The second question was whether or not there are any differences between the planned dose and 5D dose under the influence of inter- and intra-fractional variations in the patient anatomy for both modalities. Methods: A total of 45 patients (25 IMRT patients and 20 PSPT patients) were used to quantify the tumor shrinkage in terms of the change of the primary gross tumor volume (GTVp). All patients were randomized to receive either IMRT or PSPT for NSCLC. Treatment planning goals were identical for both groups. All patients received 5 to 8 weekly repeated 4-dimensional computed tomography (4DCT) scans during the course of radiation treatments. The original GTVp contours were propagated to T50 of weekly 4DCT images using deformable image registration and their absolute volumes were measured. Statistical analysis was performed to compare the distribution of tumor shrinkage between the two population groups. In order to investigate the difference between the planned dose and the 5D dose with consideration of both breathing motion and anatomical change, we re-calculated new dose distributions at every phase of the breathing cycle for all available weekly 4DCT data sets which resulted 50 to 80 individual dose calculations for each of the 7 patients presented in this thesis. The newly calculated dose distributions were then deformed and accumulated to T50 of the planning 4DCT for comparison with the planned dose distribution. Results: At the end of the treatment, both IMRT and PSPT groups showed mean tumor volume reductions of 23.6% ( 19.2%) and 20.9% ( 17.0 %) respectively. Moreover, the mean difference in tumor shrinkage between two groups is 3% along with the corresponding 95% confidence interval, [-8%, 14%]. The rate of tumor shrinkage was highly correlated with the initial tumor volume size. For the planning dose and 5D dose comparison study, all 7 patients showed a mean difference of 1 % in terms of target coverage for both IMRT and PSPT treatment plans. Conclusions: The results of the tumor shrinkage investigation showed no statistically significant difference in tumor shrinkage between the IMRT and PSPT patients, and the tumor shrinkage between the two modalities is similar based on the 95% confidence interval. From the pilot study of comparing the planned dose with the 5D dose, we found the difference to be only 1%. Overall impression of the two modalities in terms of treatment response as measured by the tumor shrinkage and 5D dose under the influence of anatomical change that were designed under the same protocol (i.e. randomized trial) showed similar result.
Resumo:
En Harry Potter and the Philosopher's Stone, texto inaugural del ciclo novelístico de J. K. Rowling, aparecen diversos elementos y situaciones que inscriben el relato dentro del género bildungsroman (o novela de formación) y que a su vez son constitutivos del monomito estudiado por Joseph Campbell. Dentro de ese marco, el presente trabajo analizará la función que desempeña la palabra en el desarrollo del protagonista de la novela. Se sostendrá que la adquisición y el dominio pleno de una palabra permiten construir la subjetividad del personaje, quien valiéndose de esta herramienta se volverá capaz de disipar sus inquietudes frente a lo desconocido y al peso de la voz popular. El estudio se centrará en el nombre del antagonista, Lord Voldemort, su influencia en la saga y en cuán importante es que Harry sea capaz de nombrarlo por ese apelativo. Para este abordaje se utilizarán algunos conceptos de diversas disciplinas que nos permitirán advertir la injerencia de la palabra en la novela seminal de esta serie literaria y en el tránsito del personaje por la compleja senda del héroe
Resumo:
En tanto "mapa" es toda "representación gráfica que facilita el conocimiento espacial de cosas, conceptos, condiciones, procesos o eventos que conciernen al mundo humano", el término "mapa" refiere a muchas imágenes muy diferentes, que usan diversas técnicas y soportes, apelan a lenguajes visuales muy heterogéneos, convenciones gráficas que han variado a lo largo del tiempo, etcétera. Este trabajo propone dos categorías metodológicas para abordar la pluralidad de la imagen cartográfica sin renunciar a esa definición amplia e inclusiva. La primera es la noción de género cartográfico, que permite agrupar y clasificar mapas que comparten claves temáticas, estilísticas, técnicas y/o composicionales. La segunda es la noción de serie, porque el armado de una serie crea claves de lectura y de interpretación y, consecuentemente, un mismo mapa no comunica lo mismo en dos series diferentes. Con ejemplos se discutirán las potencialidades y las limitaciones de estas propuestas metodológicas.
Resumo:
En tanto "mapa" es toda "representación gráfica que facilita el conocimiento espacial de cosas, conceptos, condiciones, procesos o eventos que conciernen al mundo humano", el término "mapa" refiere a muchas imágenes muy diferentes, que usan diversas técnicas y soportes, apelan a lenguajes visuales muy heterogéneos, convenciones gráficas que han variado a lo largo del tiempo, etcétera. Este trabajo propone dos categorías metodológicas para abordar la pluralidad de la imagen cartográfica sin renunciar a esa definición amplia e inclusiva. La primera es la noción de género cartográfico, que permite agrupar y clasificar mapas que comparten claves temáticas, estilísticas, técnicas y/o composicionales. La segunda es la noción de serie, porque el armado de una serie crea claves de lectura y de interpretación y, consecuentemente, un mismo mapa no comunica lo mismo en dos series diferentes. Con ejemplos se discutirán las potencialidades y las limitaciones de estas propuestas metodológicas.
Resumo:
En tanto "mapa" es toda "representación gráfica que facilita el conocimiento espacial de cosas, conceptos, condiciones, procesos o eventos que conciernen al mundo humano", el término "mapa" refiere a muchas imágenes muy diferentes, que usan diversas técnicas y soportes, apelan a lenguajes visuales muy heterogéneos, convenciones gráficas que han variado a lo largo del tiempo, etcétera. Este trabajo propone dos categorías metodológicas para abordar la pluralidad de la imagen cartográfica sin renunciar a esa definición amplia e inclusiva. La primera es la noción de género cartográfico, que permite agrupar y clasificar mapas que comparten claves temáticas, estilísticas, técnicas y/o composicionales. La segunda es la noción de serie, porque el armado de una serie crea claves de lectura y de interpretación y, consecuentemente, un mismo mapa no comunica lo mismo en dos series diferentes. Con ejemplos se discutirán las potencialidades y las limitaciones de estas propuestas metodológicas.
Resumo:
En Harry Potter and the Philosopher's Stone, texto inaugural del ciclo novelístico de J. K. Rowling, aparecen diversos elementos y situaciones que inscriben el relato dentro del género bildungsroman (o novela de formación) y que a su vez son constitutivos del monomito estudiado por Joseph Campbell. Dentro de ese marco, el presente trabajo analizará la función que desempeña la palabra en el desarrollo del protagonista de la novela. Se sostendrá que la adquisición y el dominio pleno de una palabra permiten construir la subjetividad del personaje, quien valiéndose de esta herramienta se volverá capaz de disipar sus inquietudes frente a lo desconocido y al peso de la voz popular. El estudio se centrará en el nombre del antagonista, Lord Voldemort, su influencia en la saga y en cuán importante es que Harry sea capaz de nombrarlo por ese apelativo. Para este abordaje se utilizarán algunos conceptos de diversas disciplinas que nos permitirán advertir la injerencia de la palabra en la novela seminal de esta serie literaria y en el tránsito del personaje por la compleja senda del héroe
Resumo:
En Harry Potter and the Philosopher's Stone, texto inaugural del ciclo novelístico de J. K. Rowling, aparecen diversos elementos y situaciones que inscriben el relato dentro del género bildungsroman (o novela de formación) y que a su vez son constitutivos del monomito estudiado por Joseph Campbell. Dentro de ese marco, el presente trabajo analizará la función que desempeña la palabra en el desarrollo del protagonista de la novela. Se sostendrá que la adquisición y el dominio pleno de una palabra permiten construir la subjetividad del personaje, quien valiéndose de esta herramienta se volverá capaz de disipar sus inquietudes frente a lo desconocido y al peso de la voz popular. El estudio se centrará en el nombre del antagonista, Lord Voldemort, su influencia en la saga y en cuán importante es que Harry sea capaz de nombrarlo por ese apelativo. Para este abordaje se utilizarán algunos conceptos de diversas disciplinas que nos permitirán advertir la injerencia de la palabra en la novela seminal de esta serie literaria y en el tránsito del personaje por la compleja senda del héroe
Resumo:
En tanto "mapa" es toda "representación gráfica que facilita el conocimiento espacial de cosas, conceptos, condiciones, procesos o eventos que conciernen al mundo humano", el término "mapa" refiere a muchas imágenes muy diferentes, que usan diversas técnicas y soportes, apelan a lenguajes visuales muy heterogéneos, convenciones gráficas que han variado a lo largo del tiempo, etcétera. Este trabajo propone dos categorías metodológicas para abordar la pluralidad de la imagen cartográfica sin renunciar a esa definición amplia e inclusiva. La primera es la noción de género cartográfico, que permite agrupar y clasificar mapas que comparten claves temáticas, estilísticas, técnicas y/o composicionales. La segunda es la noción de serie, porque el armado de una serie crea claves de lectura y de interpretación y, consecuentemente, un mismo mapa no comunica lo mismo en dos series diferentes. Con ejemplos se discutirán las potencialidades y las limitaciones de estas propuestas metodológicas.
Resumo:
For the production of the orthophoto map Vernagtferner 1979, scale I: 10000, photographs of the flight "Hintereisferner 1979" were used, which have been found to be very suitable for differential rectification. Control points were determined before the flight took place. The processing of nine stereopairs was carried out on an analytical plotter. Simultaneously with the on-line plotting of the contour lines the reference data for the computation of the profiles for the differential rectification were recorded. The orthophoto map was covered by four aerial photographs. A smooth data transfer was ensured because the same computer was used for the data acquisition and the differential rectification. Two printing originals were prepared, one for the outline drawings with contour lines and another for the orthophoto. The print was done in black for the two copies. The data acquisition, the computation of the scanning profiles for the othoprojector and the procedure of the differential rectification are described. The reason for the use of on-line drawn contour lines is explained. Further applications, also for digital contour lines, are introduced. Possibilities for the achievement of high photo quality during the reproduction are discussed.
Resumo:
During the cruise of the" Mabahiss" from Zanzibar to Colombo at Station 133 (1° 25' 54" S. to 1° 19' 42" S. and 66° 34' 12" E. to 66° 35' 18" E.) several small rock fragments were brought up in the Monegasque net; and, since at this position there is no possibility of the material being transferred by floating Ice, these specimens are of some interest as samples of oceanic rock foundations. All the rocks have a black appearance, but in the majority this skin is of negligible thickness. Exceptionally, however, it may attain to 1/3 in. (St. 133, 8), and then the specimens are rounded. The coating is made of dark opaque manganese material. At Station 166 one or two similar specimens of angular basalt were found in the trawl consisting mainly of manganese nodules.
Resumo:
Palaeoclimatic and paleoenvironmental high latitude records in the Southern Hemisphere are scarce compared to the northern counterpart. However, understanding global evolution of environmental systems during sudden climate changes is inseparable from an equivalent knowledge of both Hemispheres. In this context, a high-resolution study of lacustrine sediments from Laguna Potrok Aike, Santa Cruz province, Patagonia, Argentina, was conducted for the Lateglacial period using concurrent X-Ray Fluorescence (XRF) and Scanning electron microscope analyses. Peaks of Ca/Si and Mn, and occurrences of the green alga Phacotus lenticularis have been interpreted as variations in ventilation of the water column from 13.6 to 11.1 ka cal. BP. During this interval, mild climate conditions during the Younger Dryas are characterized by relatively weak westerlies favouring the formation of a stratified water body as indicated by preserved manganese and Ca/Si peaks and high Total Organic Carbon (TOC) values. In this environment, water in the epilimnion can reach sufficiently high temperature to allow P. lenticularis to grow. Colder conditions are marked by peaks in Ca without P. lenticularis and occur during the Antarctic Cold Reversal (ACR). In this Lateglacial interval, micropumices were also detected in large amount. Image analysis of thin sections allowed the counting and size measurement of detrital particles and micropumices separately. Micropumices significantly influence the iron and titanium content, hence preventing to use them as proxies of detrital input in this interval.
Resumo:
A new topographic database for King George Island, one of the most visited areas in Antarctica, is presented. Data from differential GPS surveys, gained during the summers 1997/98 and 1999/2000, were combined with up to date coastlines from a SPOT satellite image mosaic, and topographic information from maps as well as from the Antarctic Digital Database. A digital terrain model (DTM) was generated using ARC/INFO GIS. From contour lines derived from the DTM and the satellite image mosaic a satellite image map was assembled. Extensive information on data accuracy, the database as well as on the criteria applied to select place names is given in the multilingual map. A lack of accurate topographic information in the eastern part of the island was identified. It was concluded that additional topographic surveying or radar interferometry should be conducted to improve the data quality in this area. In three case studies, the potential applications of the improved topographic database are demonstrated. The first two examples comprise the verification of glacier velocities and the study of glacier retreat from the various input data-sets as well as the use of the DTM for climatological modelling. The last case study focuses on the use of the new digital database as a basic GIS (Geographic Information System) layer for environmental monitoring and management on King George Island.
Resumo:
We investigated carbon acquisition by the N2-fixing cyanobacterium Trichodesmium IMS101 in response to CO2 levels of 15.1, 37.5, and 101.3 Pa (equivalent to 150, 370, and 1000 ppm). In these acclimations, growth rates as well as cellular C and N contents were measured. In vivo activities of carbonic anhydrase (CA), photosynthetic O2 evolution, and CO2 and HCO3- fluxes were measured using membrane inlet mass spectrometry and the 14C disequilibrium technique. While no differences in growth rates were observed, elevated CO2 levels caused higher C and N quotas and stimulated photosynthesis and N2 fixation. Minimal extracellular CA (eCA) activity was observed, indicating a minor role in carbon acquisition. Rates of CO2 uptake were small relative to total inorganic carbon (Ci) fixation, whereas HCO{3 contributed more than 90% and varied only slightly over the light period and between CO2 treatments. The low eCA activity and preference for HCO3- were verified by the 14C disequilibrium technique. Regarding apparent affinities, half-saturation concentrations (K1/2) for photosynthetic O2 evolution and HCO3- uptake changed markedly over the day and with CO2 concentration. Leakage (CO2 efflux : Ci uptake) showed pronounced diurnal changes. Our findings do not support a direct CO2 effect on the carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) but point to a shift in resource allocation among photosynthesis, carbon acquisition, and N2 fixation under elevated CO2 levels. The observed increase in photosynthesis and N2fixation could have potential biogeochemical implications, as it may stimulate productivity in N-limited oligotrophic regions and thus provide a negative feedback in rising atmospheric CO2 levels.
Resumo:
This data set provides a detailed inventory of lakes in the Lena Delta, northern Siberia, with respect to the lakes' association with one of the three geomorphological main terraces of the Lena Delta. The inventory is based on Landsat-7 ETM+ image data and spatial analysis in a Geographical Information System (GIS). Several morphometric lake attributes were determined from the resulting dataset and statistically analyzed. Significant differences in the morphometric lake characteristics allowed the distinction of a mean lake type for each main terrace. The lake types reflect the special lithological and cryolithological conditions and geomorphological processes prevailing on each terrace. In Morgenstern et al. (2008), special focus was laid on the investigation of lake orientation and the discussion of possible mechanisms for the evolution of the second terrace's oriented lakes.