27 resultados para Reflection

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r(2) ? -0.86) as well as calcium release (r(2) ? -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r(2) = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

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The aim of this study was to evaluate, using visual assessment, an experimental optical sensor measuring perpendicular reflection intensity (PRI) as an indicator of enamel caries lesion activity/inactivity. Forty teeth with either an active or an inactive enamel lesion were selected from a pool of extracted teeth. Each tooth was cut into halves, with a clinically sound half and a half with a non-cavitated enamel lesion. After gentle plaque removal, the teeth were kept moistened. The lesions were then photographed and a defined measuring site per lesion was chosen and indicated with an arrow on a printout. Independently, the chosen site was visually assessed for lesion activity, and its glossiness was measured with PRI assessment. Surface roughness (SR) was assessed with optical profilometry using a confocal microscope. Visual assessment and PRI were repeated after several weeks and a reliability analysis was performed. For enamel lesions visually scored as active versus inactive, significantly different values were obtained with both PRI and SR. PRI values of the clinically sound control surfaces were significantly different only from active lesions. Generally, inactive lesions had the same glossiness and the same roughness as the sound control surfaces. The reliabilities for visual assessment (? = 0.89) and for PRI (ICC = 0.86) were high. It is concluded that, within the limits of this study, PRI can be regarded as a promising tool for quantitative enamel lesion activity assessment. There is scope and potential for the PRI device to be considerably improved for in vivo use.

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To support development tools like debuggers, runtime systems need to provide a meta-programming interface to alter their semantics and access internal data. Reflective capabilities are typically fixed by the Virtual Machine (VM). Unanticipated reflective features must either be simulated by complex program transformations, or they require the development of a specially tailored VM. We propose a novel approach to behavioral reflection that eliminates the barrier between applications and the VM by manipulating an explicit tower of first-class interpreters. Pinocchio is a proof-of-concept implementation of our approach which enables radical changes to the interpretation of programs by explicitly instantiating subclasses of the base interpreter. We illustrate the design of Pinocchio through non-trivial examples that extend runtime semantics to support debugging, parallel debugging, and back-in-time object-flow debugging. Although performance is not yet addressed, we also discuss numerous opportunities for optimization, which we believe will lead to a practical approach to behavioral reflection.

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Publishing is an essential means of validation and communication of research. This is no different in transdisciplinary research, where publishing also aims at contributing to the development of society through sharing of knowledge. In the scientific world, authors need to disseminate and validate results, reflect on issues, and participate in debates. On the other hand, institutions and individuals are assessed according to their publication record – as probably the most influential of all current evaluation criteria. Occupying the space between article production and counting impact factors, journal editors and reviewers play an important role in defining and using rules to assess and improve the work submitted to them. Publishing transdisciplinary research poses specific challenges, in particular with regard to peer-review processes, as it addresses different knowledge communities with different value systems and purposes.

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Along a downstream stretch of River Mure , Romania, adult males of two feral fish species, European chub (Leuciscus cephalus) and sneep (Chondrostoma nasus) were sampled at four sites with different levels of contamination. Fish were analysed for the biochemical markers hsp70 (in liver and gills) and hepatic EROD activity, as well as several biometrical parameters (age, length, wet weight, condition factor). None of the biochemical markers correlated with any biometrical parameter, thus biomarker reactions were related to site-specific criteria. While the hepatic hsp70 level did not differ among the sites, significant elevation of the hsp70 level in the gills revealed proteotoxic damage in chub at the most upstream site, where we recorded the highest heavy metal contamination of the investigated stretch, and in both chub and sneep at the site right downstream of the city of Arad. In both species, significantly elevated hepatic EROD activity downstream of Arad indicated that fish from these sites are also exposed to organic chemicals. The results were indicative of impaired fish health at least at three of the four investigated sites. The approach to relate biomarker responses to analytical data on pollution was shown to fit well the recent EU demands on further enhanced efforts in the monitoring of Romanian water quality.

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Dynamic, unanticipated adaptation of running systems is of interest in a variety of situations, ranging from functional upgrades to on-the-fly debugging or monitoring of critical applications. In this paper we study a particular form of computational reflection, called unanticipated partial behavioral reflection, which is particularly well-suited for unanticipated adaptation of real-world systems. Our proposal combines the dynamicity of unanticipated reflection, i.e. reflection that does not require preparation of the code of any sort, and the selectivity and efficiency of partial behavioral reflection. First, we propose unanticipated partial behavioral reflection which enables the developer to precisely select the required reifications, to flexibly engineer the metalevel and to introduce the meta behavior dynamically. Second, we present a system supporting unanticipated partial behavioral reflection in Squeak Smalltalk, called Geppetto, and illustrate its use with a concrete example of a web application. Benchmarks validate the applicability of our proposal as an extension to the standard reflective abilities of Smalltalk.

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Code executed in a fully reflective system switches back and forth between application and interpreter code. These two states can be seen as contexts in which an expression is evaluated. Current language implementations obtain reflective capabilities by exposing objects to the interpreter. However, in doing so these systems break the encapsulation of the application objects. In this paper we propose safe reflection through polymorphism, \ie by unifying the interface and ensuring the encapsulation of objects from both the interpreter and application context. We demonstrate a \emphhomogeneous system that defines the execution semantics in terms of itself, thus enforcing that encapsulation is not broken.