191 resultados para Abbe refractor
Letter written by Napoleon Buonaparte (Bonaparte) to Guillaume Thomas Francois Raynal, June 24, 1790
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Translation: Sir, It will probably be difficult for you to remember among the many strangers who annoy you with their admiration of a person to whom you kindly made civilities last year1 during a pleasant conversation about Corsica. I would be grateful if you could take a look at this sketch of his history.2 I present here the first of two letters. If you agree to them, I will send you the end. My brother, whom I recommend not to forget his deputies' commission to escort Paoli to his country,3 and to come and receive a lesson in virtue and humanity, will give them to you. I respectfully your most humble and obedient servant.4 Buonaparte, artillery officer Ajaccio, [Corsica] June 24 the first year of freedom [1790]5 1 Relations between Napoleon and Raynal have begun in 1789, which seems to confirm a confidence to Las Cases ( Memorial of St. Helena , La Pléiade , vol. I, p. 83) . 2 Latest version of history project of Corsica : Letters on Corsica to Abbe Raynal . 3 Joseph is part of a delegation sent by the city of Ajaccio to host Paoli 's return from exile in London . In doing so he has to go through Marseille where Raynal resides. 4 Shipping autograph, National Archives , 400 AP Biography 1. In the first years of Napoleon Bonaparte (1840) , Coston gives a rough version of this letter that it dates from 1786 , which is impossible because Raynal did not return to France that ' in 1787. Published for the first time in the Memories of Lord Holland (1851) , shipping is now kept in the national Archives Napoleons funds . 5 The letter is dated "June 24, the first year of freedom" (the word "freedom" is underlined twice). Given the dates of stay in Corsica Napoleon, it seems that is present in Ajaccio the month of June in 1790.
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La construcción es una de las industrias que mayores accidentes laborales genera, en esta investigación se realizó un análisis retrospectivo para determinar si existe alguna relación entre la ocurrencia de accidentes y la fecha de entrega de una meta, debido al incremento en la cantidad de trabajo expresado por la cantidad de días y horas extras trabajados, se cuenta con información de la accidentalidad de cinco empresas constructoras de un gran proyecto vial en Colombia en los años de 2012 y 2013. Se analizó la información correspondiente a la nómina de las mismas empresas, con el valor de la nómina mensual, el valor de las incapacidades mensuales y la cantidad de trabajadores por cada empresa en cada periodo. El manejo de los datos se hizo con EXCEL y el análisis estadístico con STATA 11.1, se usó la correlación de Spearman para encontrar la relación entre la cantidad de accidentes acumulados y: la cantidad acumulada de días trabajados en cada mes, la cantidad acumulada de horas extras trabajadas mensualmente y el costo acumulado en porcentaje de la nómina mensual, encontrándose en todos los casos una relación lineal. Por otra parte, se realizó una prueba binomial para establecer la relación de la fecha de entrega de la meta con la accidentalidad 30 días antes y después, encontrando que la accidentalidad aumenta en la proximidad previa a la entrega de la meta
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Una lente está formada por dos dioptrios esféricos separados entre sí por una distancia, e, contada entre sus polos. Supondremos que a su izquierda tenemos un medio transmisor de la luz cuyo índice de refracción es, n, a su derecha otro de índice nï y el material que lo forma tiene como índice nõ. Los radios de curvatura de ambos dispositivos son: r1 y r2. cada uno de los dioptrios tiene un foco imagen paraxial donde se concentran los rayos que proceden del infinito siendo paralelos al eje. Para su cálculo utilizaremos el invariable de Abbe. Es un sistema de difícil cálculo al operar con fracciones.
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We hypothesized that the hepatotoxicity that develops after the induction of oxidative stress (induced by d-galactosamine [GalN]) can be ameliorated by alpha-tocopherol (ATC) and the soy isoflavone daidzein. To test this, we ranked and assigned male Wistar rats into 6 groups, which involved pretreatment (ATC or daidzein) for 1 hour followed by treatment (GalN) for 23 hours. Histopathologic analysis showed that GalN administration induced marked necrosis (P < .001), steatosis (P < .001), both lobular and portal inflammations (P < .001), overall histopathologic score (P < .001), and activation of caspase-3 in the liver (P < .001). Immunohistochemical staining of malondialdehyde-protein adducts, a measure of oxidative stress, was increased in response to GalN (P < .001). Paradoxically, there were increases in total (P < .05) and cytosolic superoxide dismutase (P < .001) activities after GalN administration, indicative of an up-regulation of antioxidant defenses. The concentration of total protein (P < .001), albumin (P < .01), and globulin fractions (P < .001) in the plasma, as well as the activity of aspartate aminotransferase (P < .001), was significantly perturbed after GalN treatment, reflective of overall acute hepatic injury. Administration of daidzein showed a significant amelioration of the Ga1N-induced increase in malondialdehyde-protein adducts (P < .01) and cytosolic superoxide dismutase activities (P < .01) in the liver. However, all other variables were not significantly altered in response to daidzein. In response to ATC pretreatment, the total histopathologic score (P < .05), degree of necrosis (P < .05), and both lobular (P < .05) and portal (P = .05) inflammations were significantly ameliorated. To conclude, both daidzein and ATC protect the liver against oxidative damage possibly via different pathways.
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Purpose. Hyperopic retinal defocus (blur) is thought to be a cause of myopia. If the retinal image of an object is not clearly focused, the resulting blur is thought to cause the continuing lengthening of the eyeball during development causing a permanent refractive error. Both lag of accommodation, especially for near targets, and greater variability in the accommodative response, have been suggested as causes of increased hyperopic retinal blur. Previous studies of lag of accommodation show variable findings. In comparison, greater variability in the accommodative response has been demonstrated in adults with late onset myopia but has not been tested in children. This study looked at the lag and variability of accommodation in children with early onset myopia. Methods. Twenty-one myopic and 18 emmetropic children were tested. Dynamic measures of accommodation and pupil size were made using eccentric photorefraction (Power Refractor) while children viewed targets set at three different accommodative demands (0.25, 2, and 4 D). Results. We found no difference in accommodative lag between groups. However, the accommodative response was more variable in the myopes than emmetropes when viewing both the near (4 D) and far (0.25 D) targets. Since pupil size and variability also varied, we analyzed the data to determine whether this could account for the inter-group differences in accommodation variability. Variation in these factors was not found to be sufficient to explain these differences. Changes in the accommodative response variability with target distance were similar to patterns reported previously in adult emmetropes and late onset myopes. Conclusions. Children with early onset myopia demonstrate greater accommodative variability than emmetropic children, and have similar patterns of response to adult late onset myopes. This increased variability could result in an increase in retinal blur for both near and far targets. The role of accommodative variability in the etiology of myopia is discussed.
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A remote haploscopic video refractor was used to assess vergence and accommodation responses in a group of 32 emmetropic, orthophoric, symptom free, young adults naïve to vision experiments in a minimally instructed setting. Picture targets were presented at four positions between 2 m and 33 cm. Blur, disparity and looming cues were presented in combination or separately to asses their contributions to the total near response in a within-subjects design. Response gain for both vergence and accommodation reduced markedly whenever disparity was excluded, with much smaller effects when blur and proximity were excluded. Despite the clinical homogeneity of the participant group there were also some individual differences.
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This work reports on an experience of continual development courses for in-service teachers from some high schools of Bauru's (SP) region, for whom a specific workshop on assembling of refractor telescopes has been carried out in order to supplement their knowledge in astronomy. In the current article, the importance of the practice (or "knowing") in the context of their academic formation is discussed as well as some steps on the assembling of low cost refractor telescopes are described. The main results obtained from the participation of these teachers in the proposed activities are also presented.
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OBJETIVO: Pesquisar um fator de correção para avaliação do erro refrativo sem a utilização da cicloplegia. MÉTODOS: Foram estudados 623 pacientes (1.246 olhos), de ambos os sexos, com idade entre 3 e 40 anos. As refratometrias estática e dinâmica foram obtidas usando-se o refrator automático Shin-Nippon Accuref-K 9001. A cicloplegia foi obtida com a instilação de uma gota de colírio ciclopentolato a 1%, com refratometria estática 30 minutos após. Os dados foram submetidos à análise estatística usando a técnica do modelo de regressão linear e modelo de regressão múltipla do valor dióptrico com e sem cicloplegia, em função da idade. RESULTADOS: A correlação entre valores dióptricos sem e com cicloplegia quanto ao erro astigmático variou de 81,52% a 92,27%. Quanto ao valor dióptrico esférico, a correlação foi menor (53,57% a 87,78%). O mesmo se observou em relação ao eixo do astigmatismo (28,86% a 58,80%). O modelo de regressão múltipla em função da idade mostrou coeficiente de determinação múltiplo maior para a miopia (86,38%) e astigmatismo (79,79%). O menor coeficiente foi observado para o eixo do astigmatismo (17,70%). CONCLUSÃO: Avaliando-se os erros refrativos com e sem cicloplegia, observou-se alta correlação nas ametropias cilíndricas. Foram desenvolvidas equações matemáticas como fator de correção para refratometrias dos pacientes sem cicloplegia, portadores de ametropias cilíndricas e esféricas.
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OBJETIVO: O objetivo geral foi detectar fatores ambliopigênicos em uma população de pré-escolares, utilizando exames refratométricos e o PhotoScreenerTM (PS) e o objetivo específico foi verificar se a avaliação feita com o PS é útil como método de triagem em campanhas de prevenção de ambliopia em crianças. MÉTODOS: Foi realizado um estudo observacional, prospectivo, de janeiro a dezembro de 2007, avaliando-se 227 crianças pré-escolares, com o intuito de detectar, através da aplicação de um questionário, exames refratométricos e fotografias utilizando o PS, a presença de fatores causadores de ambliopia na população de estudo. Todas as crianças foram avaliadas pelo PS. em seguida, todas as crianças foram submetidas à cicloplegia , sendo avaliadas usando refrator automático Shin Nippon®. As crianças detectadas como portadoras de problemas oculares receberam prescrição óptica, segundo os critérios: hipermetropia maior que +1,50 D, miopia maior que -1,00 D e astigmatismo maior que 1,00 D. Analisaram-se os dados através do teste de concordância de Goodman, estatística descritiva e estudo da especificidade e sensibilidade ao emprego do PS, comparando os resultados com ele obtidos, com os resultados dos outros métodos de avaliação oftalmológica. RESULTADOS: A distribuição entre os sexos foi semelhante, sendo que a maioria das crianças apresentava quatro ou cinco anos de idade. A sensibilidade (S) do PS, comparando-se o resultado obtido neste aparelho com o autorrefrator sob cicloplegia, foi de 50,9%. Já a especificidade foi de 78,9%; valor preditivo positivo 70%; valor preditivo negativo 62,5% e acurácia 65,1%. CONCLUSÕES: Das 101 crianças cujas fotografias tiradas através do PS puderam ser analisadas satisfatoriamente, trinta e seis apresentavam erro refrativo que necessitou de correção. O PS, quando comparado com equivalente esférico do autorrefrator sob cicloplegia, é um método razoável de triagem, embora a sensibilidade não seja boa. Um ponto positivo a ser ressaltado é o considerável valor de especificidade.
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We present a recent development in holography with multimode, large free-spectral range (FSR) diode lasers in photorefractive sillenite crystals. A novel refractometry method based on this type of holographic recording in Bi12TiO20 (BTO) crystals is proposed. The holographic image of a prism-shaped transparent sample appears covered of interference fringes, and as the sample is properly translated, the fringes run along the holographic image. An expression providing the refractive index of the medium as a function of the sample displacement and the correspondent number of running fringes was derived. The refractive indexes of optical (BK7) glass, ethanol, hexan, cumene and aqueous solution of NaCl with different concentrations were measured in order to test the method. The obtained results are in good agreement with the ones reported in literature or measured by us using a commercial Abbe refractometre. (c) 2006 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)