975 resultados para Photo-engraving
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This work reports on the synthesis and characterization of the ligand 3-hexadecylpentane-2,4-drone (Hhdacac) and its Eu(3+) complexes Eu(hdacac)(6) center dot 2H(2)O, Eu(hdacac)(6) center dot phen and Eu(hdacac)(6) center dot tta, where phen and tta denote 1,10-phenanthroline and thenoyltrifluoroacetone, respectively. These new compounds present long carbon chains and their expected miscibility into non-polar ambients is confirmed by the emission spectra of Eu(hdacac)6 center dot tta in hexane. Moreover, the amphiphilic properties of Eu(hdacac)6 complexes allow the obtainment of thin luminescent films by the Langmuir-Blodgett technique. In both cases (solids and films), the typical antenna effect of beta-diketonates is observed. The alluring characteristics of these compounds raise great interest in many fields of Materials Science, like photo- and electro-luminescent materials (mainly thin ""organic"" films), metal catalysts or probes in non-polar solutions, and Langmuir-Blodgett films of several compositions. For the characterization of these products, nuclear magnetic resonance spectroscopy ((1)H NMR), thermogravimetric analysis, elementary analyses (C, H), scanning electron microscopy (energy dispersive X-ray spectroscopy), absorption (UV-vis/FT-IR) and photoluminescence spectroscopies were used. (c) 2008 Elsevier B.V. All rights reserved.
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In adolescent idiopathic scoliosis (AIS) there has been a shift towards increasing the number of implants and pedicle screws, which has not been proven to improve cosmetic correction. To evaluate if increasing cost of instrumentation correlates with cosmetic correction using clinical photographs. 58 Lenke 1A and B cases from a multicenter AIS database with at least 3 months follow-up of clinical photographs were used for analysis. Cosmetic parameters on PA and forward bending photographs included angular measurements of trunk shift, shoulder balance, rib hump, and ratio measurements of waist line asymmetry. Pre-op and follow-up X-rays were measured for coronal and sagittal deformity parameters. Cost density was calculated by dividing the total cost of instrumentation by the number of vertebrae being fused. Linear regression and spearman`s correlation were used to correlate cost density to X-ray and photo outcomes. Three independent observers verified radiographic and cosmetic parameters for inter/interobserver variability analysis. Average pre-op Cobb angle and instrumented correction were 54A degrees (SD 12.5) and 59% (SD 25) respectively. The average number of vertebrae fused was 10 (SD 1.9). The total cost of spinal instrumentation ranged from $6,769 to $21,274 (Mean $12,662, SD $3,858). There was a weak positive and statistically significant correlation between Cobb angle correction and cost density (r = 0.33, p = 0.01), and no correlation between Cobb angle correction of the uninstrumented lumbar spine and cost density (r = 0.15, p = 0.26). There was no significant correlation between all sagittal X-ray measurements or any of the photo parameters and cost density. There was good to excellent inter/intraobserver variability of all photographic parameters based on the intraclass correlation coefficient (ICC 0.74-0.98). Our method used to measure cosmesis had good to excellent inter/intraobserver variability, and may be an effective tool to objectively assess cosmesis from photographs. Since increasing cost density only improves mildly the Cobb angle correction of the main thoracic curve and not the correction of the uninstrumented spine or any of the cosmetic parameters, one should consider the cost of increasing implant density in Lenke 1A and B curves. In the area of rationalization of health care expenses, this study demonstrates that increasing the number of implants does not improve any relevant cosmetic or radiographic outcomes.
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The objective of this study was to evaluate in vitro light activation of the nano-filled resin composite Vita shade A1 and A3 with a halogen lamp (QTH) and argon ion laser by Knoop microhardness profile. Materials and methods: Specimens of nanofilled composite resin (Z350-3 M-ESPE) Vita shade A1 and A3 were prepared with a single increment inserted in 2.0-mm-thick and 3-mm diameter disc-shaped Teflon mold. The light activation was performed with QTH for 20 s (with an intensity of approximately 1,000 mW/cm(2) and 700 mW/cm(2)) and argon ion laser for 10 s (with a power of 150 mW and 200 mW). Knoop microhardness test was performed after 24 h and 6 months. The specimens were divided into the 16 experimental groups (n = 10), according to the factors under study: photoactivation form, resin shade, and storage time. Knoop microhardness data was analyzed by a factorial ANOVA and TukeyA ` s tests at the 0.05 level of significance. Results: Argon ion laser was not able to photo-activate the darker shade of the nanofilled resin composite evaluated but when used with 200 mW it can be as effective as QTH to photo-activate the lighter shade with only 50% of the time exposure. After 6 months storage, an increase in the means of Knoop microhardness values were observed. Conclusions: Light-activation significantly influenced the Knoop microhardness values for the darker nanofilled resin composite.
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Objectives. The purpose of this study was to evaluate how curing protocol affects the extent of polymerization of dual-cured resin cements. Methods. Four commercial resin cements were used (DuoLink, Panavia F 2.0, Variolink II and Enforce). The extent of polymerization of the resin cements cured under different conditions was measured using a (1)H Stray-Field MRI method, which also enabled to probe molecular mobility in the kHz frequency range. Results. Resin cements show well distinct behaviours concerning chemical cure. Immediate photo-activation appears to be the best choice for higher filler loaded resin cements (Panavia F 2.0 and Variolink). A photo-activation delay (5 min) did not induce any significant difference in the extent of polymerization of all cements. Significance. The extent of polymerization of dual-cured resin cements considerably changed among products under various curing protocols. Clinicians should optimize the materials choice taking into account the curing characteristics of the cements. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
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The spectral sensitivities of avian retinal photoreceptors are examined with respect to microspectrophotometric measurements of single cells, spectrophotometric measurements of extracted or in vitro regenerated visual pigments, and molecular genetic analyses of visual pigment opsin protein sequences. Bird species from diverse orders are compared in relation to their evolution, their habitats and the multiplicity of visual tasks they must perform. Birds have five different types of visual pigment and seven different types of photo receptor-rods, double (uneven twin) cones and four types of single cone. The spectral locations of the wavelengths of maximum absorbance (lambda (max)) of the different visual pigments, and the spectral transmittance characteristics of the intraocular spectral filters (cone oil droplets) that also determine photoreceptor spectral sensitivity, vary according to both habitat and phylogenetic relatedness. The primary influence on avian retinal design appears to be the range of wavelengths available for vision, regardless of whether that range is determined by the spectral distribution of the natural illumination or the spectral transmittance of the ocular media (cornea, aqueous humour, lens, vitreous humour). Nevertheless, other variations in spectral sensitivity exist that reflect the variability and complexity of avian visual ecology. (C) 2001 Elsevier Science Ltd. All rights reserved.
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Six polyesters were synthesised from 4,4 ' -oxy-bis(benzoyl chloride) and 1,4-, 1,5-, 1,6-, 2,3-, 2,6-, and 2,7-naphthalenediol isomers. The structures of the polyesters were characterised by means of IR, inherent viscosities in tetrachloroethane (TCE), solutions at 303 K and thermal analysis. The glass transition temperatures were in the range of 425-494 K by DSC thermal analysis. All of the polyesters were irradiated in an AECL Gammacell 220 unit at a dose rate of approximately 6.7 kGy/h to doses in the range of 0-15 kGy at 77 and 300 K. ESR spectroscopy was used to examine the radicals formed during radiolysis and to measure their yields. The G-values for radical formation in the polyesters were found to be in the range 0.18-1.41 at 77 K and 0.19-0.78 at 300 K. At 77 K, up to 15% of the radicals formed on radiolysis were found to be photo-bleachable anion radicals. Annealing experiments were carried out in order to identify the neutral radicals, which were assigned to naphthyl- or phenyl- and phenoxyl-type radicals. (C) 2001 Elsevier Science Ltd. All rights reserved.
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The formation of radicals in poly(vinyl alcohol), PVA, powder irradiated at 77 K by gamma -rays and the transformations of these radicals during photolysis with visible wavelengths and on thermal annealing have been studied. After irradiation a four-line ESR spectrum was observed. It was assigned to a triplet of the C-alpha-radical (38%), with a splitting of 3.27 mT, superimposed on a doublet (62%) with a splitting of 2.7 mT. The doublet appears to be composed of two radicals, one of which is photo-bleachable (58%) and the other which is not photo-bleachable (42%). This suggests that the latter radical is a neutral radical. The photo-bleachable component of the doublet has been assigned to a carbonyl anion radical. but the second doublet due to a neutral radical is unassigned. The total G-value for formation of radicals at 77 K was found to be 2.41 +/- 0.03. Upon illumination with visible light, the anion radicals were removed and the doublet components or the spectrum diminished in intensity, while the three-line spectrum of the C-alpha-radical became more clearly visible. This transition was due to the photo-detachment of electrons from traps which were proposed to be located on carbonyl groups in the polymer resulting from incomplete hydrolysis of the vinyl acetate. The photo-decay of the anion radicals could be satisfactorily described by a two-stage process. The first stage comprised the decay of approximately 80% of the anion radicals present, while the second stage was associated with the decay of the remaining 20%. Subsequent thermal annealing of a photolysed sample to 290 K led to a change in the shape of the spectrum to form a more clearly defined triplet, As the doublet of the neutral radical decays on thermal annealing between 150 and 250K, the C-alpha-radical is formed. (C) 2001 Elsevier Science Ltd. All rights reserved.
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The majority of the world's population now resides in urban environments and information on the internal composition and dynamics of these environments is essential to enable preservation of certain standards of living. Remotely sensed data, especially the global coverage of moderate spatial resolution satellites such as Landsat, Indian Resource Satellite and Systeme Pour I'Observation de la Terre (SPOT), offer a highly useful data source for mapping the composition of these cities and examining their changes over time. The utility and range of applications for remotely sensed data in urban environments could be improved with a more appropriate conceptual model relating urban environments to the sampling resolutions of imaging sensors and processing routines. Hence, the aim of this work was to take the Vegetation-Impervious surface-Soil (VIS) model of urban composition and match it with the most appropriate image processing methodology to deliver information on VIS composition for urban environments. Several approaches were evaluated for mapping the urban composition of Brisbane city (south-cast Queensland, Australia) using Landsat 5 Thematic Mapper data and 1:5000 aerial photographs. The methods evaluated were: image classification; interpretation of aerial photographs; and constrained linear mixture analysis. Over 900 reference sample points on four transects were extracted from the aerial photographs and used as a basis to check output of the classification and mixture analysis. Distinctive zonations of VIS related to urban composition were found in the per-pixel classification and aggregated air-photo interpretation; however, significant spectral confusion also resulted between classes. In contrast, the VIS fraction images produced from the mixture analysis enabled distinctive densities of commercial, industrial and residential zones within the city to be clearly defined, based on their relative amount of vegetation cover. The soil fraction image served as an index for areas being (re)developed. The logical match of a low (L)-resolution, spectral mixture analysis approach with the moderate spatial resolution image data, ensured the processing model matched the spectrally heterogeneous nature of the urban environments at the scale of Landsat Thematic Mapper data.
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Coins and commemorative medals constitute one special repository of the history of military medicine. The numismatic record has proven to be the most enduring, albeit one of the most selective, records of the progress of history. Matters of health, and especially of military medicine, have been central to the endeavors and indeed the survival of many cultures and societies. Many such themes in the national and international history of military medicine are preserved in the medallic record. Coins and medallions thus constitute one record of the chronology of this profession, one parallel to that of the more traditional history to be found in oral and written records. This account presents a four-part classification of medical coins and medals of military interest. These examples include (1) medals that portray military surgeons and physicians; (2) medals that commemorate special events of military medicine; (3) coins that portray the themes of the discipline of military medicine and health; and (4) a miscellaneous group that includes such examples as disease touch pieces and the militarily worn medals of such bodies as the International Red Cross and the Order of St. John, the latter of which are awarded inter alia for contributions to prehospital care in the field. A representative photo archive of such exemplars is included in this account.
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A novel photoactivatable analog of antisauvagine-30 (aSvg-30), a specific antagonist for corticotropin-releasing factor (CRF) receptor, type 2 (CRF2), has been synthesized and characterized. The N-terminal amino-acid D-Phe in aSvg-30 [D-Phe11,His12] Svg((11-40)) was replaced by a phenyldiazirine, the 4-(1-azi-2,2,2-trifluoroethyl) benzoyl (ATB) residue. The photoactivatable aSvg-30 analog ATB-[ His12] Svg was tested for its ability to displace [I-125-Tyr0] oCRF or [I-125-Tyr0]Svg from membrane homogenates of human embryonic kidney (HEK) 293 cells stably transfected with cDNA coding for rat CRF receptor, type 1 ( rCRF(1)) or mouse CRF receptor, type 2beta (mCRF(2beta)). Furthermore, the ability of ATB- [His12] Svg((12-40)) to inhibit oCRF- or Svg-stimulated cAMP production of transfected HEK 293 cells expressing either rCRF(1) (HEK-rCRF(1) cells) or mCRF(2beta) (HEK-mCRF(2beta) cells) was determined. Unlike astressin and photo astressin, ATB- [His12]Svg((12-40)) showed high selective binding to mCRF(2beta) (K-i = 3.1 +/- 0.2 nM) but not the rCRF(1) receptor (K-i = 142. 5 +/- 22.3 nM) and decreased Svg-stimulated cAMP activity in mCRF(2beta)-expressing cells in a similar fashion as aSvg-30. A66-kDa protein was identified by SDS/PAGE, when the radioactively iodinated analog of ATB- [His12]Svg((12-40)) was covalently linked to mCRF(2beta) receptor. The specificity of the photoactivatable I-125-labeled CRF2beta antagonist was demonstrated with SDS/PAGE by the finding that this analog could be displaced from the receptor by antisauvagine-30, but not other unrelated peptides such as vasoactive intestinal peptide (VIP).
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Ninguém consegue sair ileso de um encontro com o currículo e com a escola, principalmente diante de relações tão assimétricas de poder que não valorizam o que as crianças têm a dizer. Quantas narrativas curriculares sobre as crianças? Quantas narrativas curriculares com as crianças? As narrativas e as fotografias se seguirão nesta pesquisa, porque com elas nos colocamos a pensar nos processos de criação curricular, explorando novas sensibilidades, novas maneiras de ver e falar, a partir das redes de sentidos, forjadas nos contextos vividos, imaginados ou pensados, dentrofora da escola. Também incluímos a forma como as crianças se relacionam com as práticas pedagógicas dos professores e do modo como se relacionam com a escola. Nessa perspectiva, interessa-nos pensar em como os usos (CERTEAU, 1994) da imagem fotográfica são capazes de afetar (e até transformar) as práticas curriculares, traçando algo da potência da/na imagem fotográfica em sua função fabuladora por meio das oficinas de fotografias realizadas com as crianças em virtude da pesquisa. A fotografia se torna potente como um recurso para provocar a invenção tessitura de outros sentidos em currículo não porque em sua materialidade ela está repleta de sentidos de currículo à priori, mas porque pode ou não, ao ser usada (CERTEAU, 1994), ao ser vista pelas crianças, agenciar outros possíveis para o currículo. Assim, o foco da discussão não é a fotografia em si nem a criança em si, ou seja, não há protagonismo nem da criança nem da fotografia. O foco está nas relações, naquilo que nos passa, isto é, na experiência estética (LARROSA, 2004b) que ocorre ao entrarmos em contato, ao vermos, ao compormos com as fotografias! Nesse sentido, pensamos as oficinas de fotografias como um dispositivo de criação e produção de acontecimentos em currículo, considerando-as máquinas de fazer “ver e falar”, o que as justifica como uma estratégia narrativa capaz de produzir acontecimentos na imagem e no mundo. Que sentidos de currículo são produzidos em multiplicidades? Pelas minoridades pretendemos movimentar nosso pensamento: que quer pensar um currículo como fabulação sem dizer o que ele é, mas no que ele vai se transformando com a chegada das crianças. No encontro das imagens com as palavras, em que o currículo vai se transformando? Sob a mesma superfície chamada currículo em extensão com as crianças, co-habitantes, encontrar os modos de olhar esse currículo e de dizê-lo por meio das fotografias, das narrativas, dos cartazes, dos desenhos, das poesias... As conversas com as crianças provocam o real, colocam em desequilíbrio algumas ideias feitas em educação, exigindo reordenações e invenções de outros pensamentos para a educação. É dessa criação de efeitos impensáveis que surge a invenção de currículos possíveis. Aprender a olhar mais (até cansar!) aquilo que não percebemos no dia a dia tem uma dimensão política muito importante; por meio desse gesto (que aprendemos com as crianças) podemos criar um novo pensamento político em educação. A partir daquilo que nos dá a ver, as crianças vão inaugurar sentidos impertinentes, desestabilizadores daquilo que chamamos de currículo e escola. O desafio consiste em falar da força contida na imagem fotográfica sem vontade de interpretá-la ou descrevê-la, mas escrever e pensar pelas fotografias num movimento de criação de sentidos e acontecer por elas.
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Trata-se esta de uma pesquisa de intervenção realizada com servidores técnico-administrativos, da Universidade Federal do Espírito Santo, ocupantes do cargo de assistente em administração, cujo objetivo principal foi analisar o trabalho sob o ponto de vista da atividade. A metodologia utilizada se baseou no referencial teórico-metodológico da Clínica da atividade, proposta por Yves Clot e seus colaboradores. Nesse percurso, a oficina de fotos foi utilizada como um procedimento de análise da atividade. Para esse estudo foram também utilizados, como referência de pesquisa, autores que postulam esse mesmo enfoque teórico metodológico. Articulando-se a estes, foram alçados estudos de pesquisadores brasileiros que trabalham com a temática nos campos da psicologia, da saúde, da educação, das clínicas do trabalho, dentre outros. O grupo associado foi composto por 10 funcionários de diferentes setores da Universidade, entre os quais, três se dispuseram a fotografar cenas do cotidiano do trabalho. Tais fotos foram escolhidas, confrontadas e analisadas pelo grupo de trabalhadores. Os trabalhadores ao se confrontarem com as situações de trabalho fotografadas viabilizaram um debate profícuo, conduzindo o grupo a pensar criticamente as atividades e os processos de trabalho que desenvolvem. A pesquisa indica que os trabalhadores procuram se reinventar e elaborar maneiras outras para enfrentar situações de trabalho que os desafiam, buscando modos diversos de atuar, o que se faz a partir da ampliação do poder de agir.
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For modern consumer cameras often approximate calibration data is available, making applications such as 3D reconstruction or photo registration easier as compared to the pure uncalibrated setting. In this paper we address the setting with calibrateduncalibrated image pairs: for one image intrinsic parameters are assumed to be known, whereas the second view has unknown distortion and calibration parameters. This situation arises e.g. when one would like to register archive imagery to recently taken photos. A commonly adopted strategy for determining epipolar geometry is based on feature matching and minimal solvers inside a RANSAC framework. However, only very few existing solutions apply to the calibrated-uncalibrated setting. We propose a simple and numerically stable two-step scheme to first estimate radial distortion parameters and subsequently the focal length using novel solvers. We demonstrate the performance on synthetic and real datasets.
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The evolution of computer animation represents one of the most relevant andrevolutionary aspects in the rise of contemporary digital visual culture (Darlew,2000), in particular, phenomena such as cinema “spectacular “ (Ibidem) and videogames. This article analyzes the characteristics of this “culture of simulation” (Turkle, 1995:20) relating the multidisciplinary and spectrum of technical and stylistic choices to the dimension of virtual characters acting. The result of these hybrid mixtures and computerized human motion capture techniques - called virtual cinema, universal capture, motion capture, etc. - cosists mainly on the sophistication of “rotoscoping”, as a new interpretation and appropriation of the captured image. This human motion capture technology, used largely by cinema and digital games, is one of the reasons why the authenticity of the animation is sometimes questioned. It is in the fi eld of 3D computer animation visual that this change is more signifi cant, appearing regularly innovative techniques of image manipulation and “hyper-cinema” (Lamarre, 2006: 31) character’s control with deeper sense of emotions. This shift in the culture that Manovich (2006: 27) calls “photo-GRAPHICS” - and Mulvey (2007) argue that creates a new form of possessive relationship with the viewer, in that it can analyze in detail the image, it can acquire it and modify it - is one of the most important aspects in the rise of Cubbit’s (2007) “cinema of attraction”. This article delves intrinsically into the analyze of virtual character animation — particularly in the fi eld of 3D computer animation and human digital acting.