976 resultados para In-visibility


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Ex vivo porcine retina laser lesions applied with varying laser power (20 mW–2 W, 10 ms pulse, 196 lesions) are manually evaluated by microscopic and optical coherence tomography (OCT) visibility, as well as in histological sections immediately after the deposition of the laser energy. An optical coherence tomography system with 1.78 um axial resolution specifically developed to image thin retinal layers simultaneously to laser therapy is presented, and visibility thresholds of the laser lesions in OCT data and fundus imaging are compared. Optical coherence tomography scans are compared with histological sections to estimate the resolving power for small optical changes in the retinal layers, and real-time time-lapse scans during laser application are shown and analyzed quantitatively. Ultrahigh-resolution OCT inspection features a lesion visibility threshold 40–50 mW (17 reduction) lower than for visual inspection. With the new measurement system, 42 of the lesions that were invisible using state-of-the-art ophthalmoscopic methods could be detected.

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PURPOSE To gain a deeper understanding of the influence of skeletal muscle fiber orientation on metabolite visibility, magnetization transfer from water, and water proton relaxation rates in (1) H MR spectra. METHODS Non-water-suppressed MR spectroscopy was performed in tibialis anterior muscle (TA) of 10 healthy adults, with the TA oriented either parallel or at the magic angle to the 3T field. Spectra were acquired with metabolite-cycled PRESS, and water inversion from 50 to 2510 ms before excitation. Water proton T2 relaxation was sampled with STEAM with echo times from 12 to 272 ms. RESULTS Apparent concentrations of total creatine (tCr), taurine, and trimethylammonium compounds were reduced by 29% to 67% when TA was parallel to B0 . Both tCr peak areas were strongly correlated to the methylene peak splitting. Magnetization transfer rates from water to tCr CH3 were not significantly different between orientations. Water T1 s were similar between orientations, but T2 s were statistically significantly shorter by 1 ms in the parallel orientation (P = 0.002). CONCLUSION Muscle metabolite visibilities in MR spectroscopy and water T2 times depend substantially on muscle fiber orientation relative to B0 . In contrast, magnetization transfer rates appear to depend on muscle composition, rather than fiber orientation. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.

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Lipid resonances from mobile lipids can be observed by (1)H NMR spectroscopy in multiple tissues and have also been associated with malignancy. In order to use lipid resonances as a marker for disease, a reference standard from a healthy tissue has to be established taking the influence of variable factors like the spinning rate into account. The purpose of our study was to investigate the effect of spinning rate variation on the HR-MAS pattern of lipid resonances in non-neoplastic brain biopsies from different regions and visualize polar and non-polar lipids by fluorescence microscopy using Nile Red staining. (1)H HR-MAS NMR spectroscopy demonstrated higher lipid peak intensities in normal sheep brain pure white matter biopsies compared to mixed white and gray matter biopsies and pure gray matter biopsies. High spinning rates increased the visibility particularly of the methyl resonances at 1.3 and the methylene resonance at 0.89ppm in white matter biopsies stronger compared to thalamus and brainstem biopsies, and gray matter biopsies. The absence of lipid droplets and presence of a large number of myelin sheaths observed in white matter by Nile Red fluorescence microscopy suggest that the observed lipid resonances originate from the macromolecular pool of lipid protons of the myelin sheath's plasma membranes. When using lipid contents as a marker for disease, the variable behavior of lipid resonances in different neuroanatomical regions of the brain and at variable spinning rates should be considered. The findings may open up interesting possibilities for investigating lipids in myelin sheaths.

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Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional

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Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional

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Se analizan los patrones de publicación y citación en ciencias humanas y sociales en Scopus en el período 2003-2012, según el alcance geográfico de la investigación. Los resultados muestran que los temas de alcance nacional tienen un predominio del español como lengua de publicación y una marcada preferencia por la autoría única frente a los patrones observados en el grupo de otros temas, no situados geográficamente, donde el inglés y la colaboración institucional es más fuerte y está más consolidada. La citación no parece estar determinada solo por el alcance geográfico de las investigaciones, sino también por el idioma de publicación, la coautoría y los perfiles de las revistas donde se publica. Se espera que los resultados den lugar a una reflexión constructiva sobre la cultura investigadora y editorial y que sean útiles como referencia para establecer criterios de evaluación en las comisiones evaluadoras y las políticas editoriales a nivel nacional

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Time series are proficiently converted into graphs via the horizontal visibility (HV) algorithm, which prompts interest in its capability for capturing the nature of different classes of series in a network context. We have recently shown [B. Luque et al., PLoS ONE 6, 9 (2011)] that dynamical systems can be studied from a novel perspective via the use of this method. Specifically, the period-doubling and band-splitting attractor cascades that characterize unimodal maps transform into families of graphs that turn out to be independent of map nonlinearity or other particulars. Here, we provide an in depth description of the HV treatment of the Feigenbaum scenario, together with analytical derivations that relate to the degree distributions, mean distances, clustering coefficients, etc., associated to the bifurcation cascades and their accumulation points. We describe how the resultant families of graphs can be framed into a renormalization group scheme in which fixed-point graphs reveal their scaling properties. These fixed points are then re-derived from an entropy optimization process defined for the graph sets, confirming a suggested connection between renormalization group and entropy optimization. Finally, we provide analytical and numerical results for the graph entropy and show that it emulates the Lyapunov exponent of the map independently of its sign.

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For suitable illumination and observation conditions, sparkles may be observed in metallic coatings. The visibility of these sparkles depends critically on their intensity, and on the paint medium surrounding the metallic flakes. Based on previous perception studies from other disciplines, we derive equations for the threshold for sparkles to be visible. The resulting equations show how the visibility of sparkles varies with the luminosity and distance of the light source, the diameter of the metallic flakes, and the reflection properties of the paint medium. The predictions are confirmed by common observations on metallic sparkle. For example, under appropriate conditions even metallic flakes as small as 1 μm diameter may be visible as sparkle, whereas under intense spot light the finer grades of metallic coatings do not show sparkle. We show that in direct sunlight, dark coarse metallic coatings show sparkles that are brighter than the brightest stars and planets in the night sky. Finally, we give equations to predict the number of visually distinguishable flake intensities, depending on local conditions. These equations are confirmed by previous results. Several practical examples for applying the equations derived in this article are provided.

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Mode of access: Internet.

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"Report No. CG-D-66-80."

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Software Configuration Management is the discipline of managing large collections of software development artefacts from which software products are built. Software configuration management tools typically deal with artefacts at fine levels of granularity - such as individual source code files - and assist with coordination of changes to such artefacts. This paper describes a lightweight tool, designed to be used on top of a traditional file-based configuration management system. The add-on tool support enables users to flexibly define new hierarchical views of product structure, independent of the underlying artefact-repository structure. The tool extracts configuration and change data with respect to the user-defined hierarchy, leading to improved visibility of how individual subsystems have changed. The approach yields a range of new capabilities for build managers, and verification and validation teams. The paper includes a description of our experience using the tool in an organization that builds large embedded software systems.

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Purpose: The following case study aims to explore management's, health professionals' and patients' experiences on the extent to which there is visibility of management support in achieving effective interdisciplinary team working, which is explicitly declared in the mission statement of a 60-bed acute rehabilitative geriatric hospital in Malta. Design/methodology/approach: A total of 21 semi-structured interviews were conducted with the above-mentioned key stakeholders. Findings: Three main distinct yet interdependent themes emerged as a result of thematic analysis: "managing a team-friendly hospital", "interdisciplinary team components", and "interdisciplinary team processes". The findings show that visibility of management support and its alignment with the process and content levels of interdisciplinary teamwork are key to integrated care for acute rehabilitative geriatric patients. Research limitations/implications: The emerging phenomena may not be reproducible in a different context; although many of the emerging themes could be comfortably matched with the existing literature. Practical implications: The implications are geared towards raising the consciousness and conscientiousness of good practice in interdisciplinary teamwork in hospitals, as well as in emphasizing organizational and management support as crucial factors for team-based organizations. Social implications: Interdisciplinary teamwork in acute rehabilitative geriatrics provides optimal quality and integrated health care delivery with the aim that the older persons are successfully discharged back to the community. Originality/value: The authors draw on solid theoretical frameworks - the complexity theory, team effectiveness model and the social identity theory - to support their major finding, namely the alignment of organizational and management support with intra-team factors at the process and content level. © Emerald Group Publishing Limited.