940 resultados para 1475-1564


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A presente dissertação pretende compreender as origens e a actividade associada à capitania-mor do mar da Índia, considerado o segundo cargo mais relevante da estrutura político-militar do Estado Português da Índia, desde 1502 a 1564. Este cargo, transferido do reino para a Índia, ainda nos primórdios da presença portuguesa, em 1502, visou assegurar os interesses da Coroa na Ásia. Após a nomeação do primeiro vice-rei para a Índia, D. Francisco de Almeida, em 1505, este ofício foi desde logo disputado e requerido pelos governadores subsequentes. Na maioria das vezes era-lhes concedida a possibilidade de indicarem ao soberano quem pretendiam ao seu lado, para os auxiliar na realização do plano de expansão gizado pela Coroa. No entanto, ao monarca assistia a palavra final. Procuramos saber quem foram os oficiais que ocuparam a capitania e compreender que espaço era esse “Mar da Índia”. Considerado o controlo do mar como a base da afirmação e alargamento da presença portuguesa na Ásia, de acordo com os planos de expansão de D. Manuel I e D. João III, é relevante percebermos qual foi a área de autoridade desta capitania. Se o espaço é relevante, também as embarcações o são, por isso, tentamos perceber que tipos de embarcações faziam parte das armadas associadas a este ofício. Após o entendimento sobre o espaço e as embarcações, foi relevante percebermos os critérios da nomeação e as funções inerentes, as quais eram, sobretudo, do foro político-militar. Todavia, os poderes outorgados à capitania, de natureza marítima, foram por vezes alargados às praças portuguesas do Estado da Índia. Percepcionar de que forma e para que fins essa autoridade se ampliou também foi motivo de discussão. Compreender o estatuto social e o impacto do cargo nas trajectórias individuais, foram aspectos que foram tidos em linha de conta ao longo do nosso estudo. Tentamos igualmente avançar com hipóteses explicativas sobre o fim deste cargo. Com este estudo pretendemos compreender como a capitania-mor do mar da Índia fez parte do funcionamento da cúpula político-militar do Estado Português da Índia, ao longo de mais de meio século, como elemento estabilizador. Constatamos que o capitão-mor do mar também foi usado pelo rei, com o intuito de controlar o governador em funções.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

ResumenHaciendo uso de la metodología prosopográfica y de un enfoque teórico de redes sociales, el presente artículo se propone investigar el funcionamiento social del conocimiento, así como sus mecanismos de transmisión en la sociedad colonial de Costa Rica. También se lleva a cabo una presentación documental de las principales líneas de evolución institucional de la educación en la época. Se llega así a constatar que el conocimiento estaba en manos de una estrecha red social de individuos conectados, enriquecidos y empoderados, que formaban parte de la elite política colonial, quienes lo vedaban sistemáticamente a otros sectores sociales de la época, y lo empleaban para apuntalar su posición social.AbstractBy means of a prosopographic study and using a social networks theoretical approach, this article explores the social functions of knowledge, as well as its ways of transmission in the Costarican colonial society. A documented presentation of the main traits of the evolution of the formal education in the period is also offered. As a result, the work concludes that knowledge was in the hands of a very narrow social network structured with very well connected individuals, who were also rich and politically powerful. These individuals used their position and their monopoly of knowledge to impede access to it to other social groups of the time, using it, at the same time, as a tool to sustain their social position.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Abstract Background Understanding spatio-temporal variation in malaria incidence provides a basis for effective disease control planning and monitoring. Methods Monthly surveillance data between 1991 and 2006 for Plasmodium vivax and Plasmodium falciparum malaria across 128 counties were assembled for Yunnan, a province of China with one of the highest burdens of malaria. County-level Bayesian Poisson regression models of incidence were constructed, with effects for rainfall, maximum temperature and temporal trend. The model also allowed for spatial variation in county-level incidence and temporal trend, and dependence between incidence in June–September and the preceding January–February. Results Models revealed strong associations between malaria incidence and both rainfall and maximum temperature. There was a significant association between incidence in June–September and the preceding January–February. Raw standardised morbidity ratios showed a high incidence in some counties bordering Myanmar, Laos and Vietnam, and counties in the Red River valley. Clusters of counties in south-western and northern Yunnan were identified that had high incidence not explained by climate. The overall trend in incidence decreased, but there was significant variation between counties. Conclusion Dependence between incidence in summer and the preceding January–February suggests a role of intrinsic host-pathogen dynamics. Incidence during the summer peak might be predictable based on incidence in January–February, facilitating malaria control planning, scaled months in advance to the magnitude of the summer malaria burden. Heterogeneities in county-level temporal trends suggest that reductions in the burden of malaria have been unevenly distributed throughout the province.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A combination of micro-Raman spectroscopy, micro-infrared spectroscopy and SEM–EDX was employed to characterize decorative pigments on Classic Maya ceramics from Copán, Honduras. Variation in red paint mixtures was correlated with changing ceramic types and improvements in process and firing techniques. We have confirmed the use of specular hematite on Coner ceramics by the difference in intensities of Raman bands. Different compositions of brown paint were correlated with imported and local wares. The carbon-iron composition of the ceramic type, Surlo Brown, was confirmed. By combining micro-Raman analysis with micro-ATR infrared and SEM–EDX, we have achieved a more comprehensive characterization of the paint mixtures. These spectroscopic techniques can be used non-destructively on raw samples as a rapid confirmation of ceramic type.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We extended an earlier study (Vision Research, 45, 1967–1974, 2005) in which we investigated limits at which induced blur of letter targets becomes noticeable, troublesome and objectionable. Here we used a deformable adaptive optics mirror to vary spherical defocus for conditions of a white background with correction of astigmatism; a white background with reduction of all aberrations other than defocus; and a monochromatic background with reduction of all aberrations other than defocus. We used seven cyclopleged subjects, lines of three high-contrast letters as targets, 3–6 mm artificial pupils, and 0.1–0.6 logMAR letter sizes. Subjects used a method of adjustment to control the defocus component of the mirror to set the 'just noticeable', 'just troublesome' and 'just objectionable' defocus levels. For the white-no adaptive optics condition combined with 0.1 logMAR letter size, mean 'noticeable' blur limits were ±0.30, ±0.24 and ±0.23 D at 3, 4 and 6 mm pupils, respectively. White-adaptive optics and monochromatic-adaptive optics conditions reduced blur limits by 8% and 20%, respectively. Increasing pupil size from 3–6 mm decreased blur limits by 29%, and increasing letter size increased blur limits by 79%. Ratios of troublesome to noticeable, and of objectionable to noticeable, blur limits were 1.9 and 2.7 times, respectively. The study shows that the deformable mirror can be used to vary defocus in vision experiments. Overall, the results of noticeable, troublesome and objectionable blur agreed well with those of the previous study. Attempting to reduce higher-order aberrations or chromatic aberrations, reduced blur limits to only a small extent.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Refraction may be affected by the forces of lids and extraocular muscles when eye direction and head direction are not aligned (oblique viewing) which might potentially influence past findings on peripheral refraction of the eye. We investigated the effect of oblique viewing on axial and peripheral refraction. In a first experiment, cycloplegic axial refractions were determined when subjects' heads were positioned to look straight-ahead through an open-view autorefractor and when the heads were rotated to the right or left by 30° with compensatory eye rotation (oblique viewing). Subjects were 16 young emmetropes (18–35 years), 22 young myopes (19–36 years) and 15 old emmetropes (45–60 years). In a second experiment, cycloplegic peripheral refraction measurements were taken out to ±34° horizontally from fixation while the subjects rotated their heads to match the peripheral refraction angles (eye in primary position with respect to the head) or the eyes were rotated with respect to the head (oblique viewing). Subjects were 10 emmetropes and 10 myopes. We did not find any significant changes in axial or peripheral refraction upon oblique viewing for any of the subject groups. In general for the range of horizontal angles used, it is not critical whether or not the eye is rotated with respect to the head during axial or peripheral refraction.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The results of a numerical investigation into the errors for least squares estimates of function gradients are presented. The underlying algorithm is obtained by constructing a least squares problem using a truncated Taylor expansion. An error bound associated with this method contains in its numerator terms related to the Taylor series remainder, while its denominator contains the smallest singular value of the least squares matrix. Perhaps for this reason the error bounds are often found to be pessimistic by several orders of magnitude. The circumstance under which these poor estimates arise is elucidated and an empirical correction of the theoretical error bounds is conjectured and investigated numerically. This is followed by an indication of how the conjecture is supported by a rigorous argument.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two different methods to measure binocular longitudinal corneal apex movements were synchronously applied. High-speed videokeratoscopy at a sampling frequency of 15 Hz and a customdesigned ultrasound distance sensor at 100 Hz were used for the left and the right eye, respectively. Four healthy subjects participated in the study. Simultaneously, cardiac electric cycle (ECG) was registered for each subject at 100 Hz. Each measurement took 20 s. Subjects were asked to suppress blinking during the measurements. A rigid headrest and a bite-bar were used to minimize undesirable head movements. Time, frequency and time-frequency representations of the acquired signals were obtained to establish their temporal and spectral contents. Coherence analysis was used to estimate the correlation between the measured signals. The results showed close correlation between both corneal apex movements and the cardiopulmonary system. Unraveling these relationships could lead to better understanding of interactions between ocular biomechanics and vision. The advantages and disadvantages of the two methods in the context of measuring longitudinal movements of the corneal apex are outlined.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The refractive error of a human eye varies across the pupil and therefore may be treated as a random variable. The probability distribution of this random variable provides a means for assessing the main refractive properties of the eye without the necessity of traditional functional representation of wavefront aberrations. To demonstrate this approach, the statistical properties of refractive error maps are investigated. Closed-form expressions are derived for the probability density function (PDF) and its statistical moments for the general case of rotationally-symmetric aberrations. A closed-form expression for a PDF for a general non-rotationally symmetric wavefront aberration is difficult to derive. However, for specific cases, such as astigmatism, a closed-form expression of the PDF can be obtained. Further, interpretation of the distribution of the refractive error map as well as its moments is provided for a range of wavefront aberrations measured in real eyes. These are evaluated using a kernel density and sample moments estimators. It is concluded that the refractive error domain allows non-functional analysis of wavefront aberrations based on simple statistics in the form of its sample moments. Clinicians may find this approach to wavefront analysis easier to interpret due to the clinical familiarity and intuitive appeal of refractive error maps.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Although comparison phakometry has been used by a number of studies to measure posterior corneal shape, these studies have not calculated the size of the posterior corneal zones of reflection they assessed. This paper develops paraxial equations for calculating posterior corneal zones of reflection, based on standard keratometry equations and equivalent mirror theory. For targets used in previous studies, posterior corneal reflection zone sizes were calculated using paraxial equations and using exact ray tracing, assuming spherical and aspheric corneal surfaces. Paraxial methods and exact ray tracing methods give similar estimates for reflection zone sizes less than 2 mm, but for larger zone sizes ray tracing methods should be used.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper estimates a simultaneous-equation model of wages and prices for Australia, underpinned by a competing claims framework of imperfect competition. Two separate co-integrating relationships for wages and prices are identified by imposing the economic hypotheses implied by the theory. The steady-state relationships for wages and prices are then embedded in a parsimonious, dynamic wage-price model. The final model is both simple and parsimonious and able to describe the process of wage and price inflation in Australia