109 research outputs found
Anterior-segment optical coherence tomography for the detection and therapeutic monitoring of corneal disorders
Background: Over recent years a revolutionary trend happened on imaging technologies to diagnose and monitor treatment of a varied group of ophthalmic pathologies. Recent reports have analyzed the microstructural changes of various ocular surface and corneal disorders, particularly ocular surface squamous neoplasia (OSSN) and keratoconus using anterior-segment optical coherence tomography (AS-OCT). Aim of this short communication is to elaborate on clinical applications AS-OCT for the detection and therapeutic monitoring of corneal disorders.
Methods: We performed an English literature search without a time limit and intending to identify articles related to the AS-OCT applications in the detection and therapeutic monitoring of corneal disorders. The most relevant articles were selected. practical points of selected papers and advantages and disadvantages of AS-OCT were retrieved from them and summarized.
Results:.Many records reported the AS-OCT applications for diagnosing many ocular surface disorders, the microstructural changes of different inflammatory, infectious, degenerative, and dystrophic corneal disorders. Its applications in identifying disease activity and therapeutic monitoring of various corneal pathologies, including stromal edema associated with angle-closure glaucoma, Fuchs endothelial dystrophy, infectious keratitis, and bullous keratopathy, are promising. The percentage of diagnostic sensitivity, specificity, and accuracy of artificial intelligence methodologies applied to AS-OCT imaging analysis today has reached 94% to 100%. Moreover, AS-OCT is very useful for analyzing the extension of scar and leukoma depth for surgical planning of partial or total corneal transplantation.
Conclusions: There is a clear prospect for expanding application of corneal OCT imaging technology, a rapid, non-invasive, and now a promising lower-cost device, which is becoming an in-office standard-of-care tool for the assessment of different corneal and ocular surface pathologies.
KEYWORDS
anterior-segment optical coherence tomography, AS-OCT, ocular surface disorders, corneal disorders, ocular surface squamous neoplasia, OSSN, keratoconu
In Vivo Corneal Microstructural Changes in Herpetic Stromal Keratitis: A Spectral-Domain Optical Coherence Tomography Analysis
Purpose: To describe and analyze the microstructural changes in herpetic stromal keratitis (HSK) observed in vivo by spectral-domain ocular coherence tomography (SD-OCT) at different stages of the disease.
Methods: A prospective, cross-sectional, observational, and comparative SD-OCT analysis of corneas with active and inactive keratitis was performed, and the pathologic differences between the necrotizing and non-necrotizing forms of the disease were analyzed.
Results: Fifty-three corneas belonging to 43 (81.1%) women and 10 (18.8%) men with a mean age of 41.0 years were included for analysis. Twenty-four (45.3%) eyes had active keratitis, and 29 (54.7%) had inactive keratitis; the majority (83.0%) had the non-necrotizing form. Most corneas (79.1%) with active keratitis showed stromal edema and inflammatory infiltrates. Almost half of the active lesions affected the visual axis, were found at mid-stromal depth, and had a medium density. By contrast, corneas with inactive keratitis were characterized by stromal scarring (89.6%), epithelial remodeling (72.4%), and stromal thinning (68.9%). In contrast to non-necrotizing corneas, those with necrotizing HSK showed severe stromal scarring, inflammatory infiltration, and thinning. Additionally, most necrotizing lesions (77.7%) affected the visual axis and had a higher density (P = 0.010).
Conclusion: Active HSK is characterized by significant epithelial and stromal thickening and the inactive disease manifests epithelial remodeling at sites of stromal thinning due to scarring. Necrotizing keratitis is characterized by distorted corneal architecture, substantial stromal inflammatory infiltration, and thinning. In vivo SD-OCT analysis permitted a better understanding of the inflammatory and repair mechanisms occurring in this blinding corneal disease
Modelo de valorización de empresas enfocado al sector financiero peruano. Caso Interbank
El presente Plan de Tesis contempla la aplicación del modelo de ingresos residuales para
la valorización de empresas del sistema financiero peruano. El objetivo principal de esta
investigación es analizar si el modelo de ingresos residuales es el más adecuado para la
valorización de empresas financieras peruanas. En este sentido, la investigación busca
identificar las fortalezas y debilidades de los modelos de valorización de empresas
financieras con el fin de determinar qué modelo presenta más fortalezas en su aplicación
a dicho sector. Asimismo, se pretende determinar si la regulación de la Superintendencia
de Banca, Seguros y AFP influye en la elección del modelo. Por último, se busca
determinar si el modelo de ingresos residuales contribuye en la obtención de un valor
fundamental más preciso de la entidad valorizada. Entre las hipótesis, dado que la
finalidad de toda valorización es la obtención del valor fundamental de la empresa, se
aplica el modelo de ingresos residuales a la empresa Interbank y se contrasta la
obtención de dicho valor mediante la simulación de Montecarlo.This Thesis Plan contemplates the application of the residual income model for the
valuation of companies of the Peruvian financial system. The main objective of this
research is to analyze whether the residual income model is the most suitable for the
valuation of Peruvian financial companies. In this sense, the research seeks to identify
the strengths and weaknesses of the valuation models of financial companies in order to
determine which model presents more strengths in its application to that sector.
Furthermore, it is intended to determine if the regulation of the Superintendence of
Banking, Insurance and AFP influences the choice of the model. Finally, it is sought to
determine if the residual income model contributes to obtaining a more precise
fundamental value of the valued entity. Among the hypotheses, given that the proposal of
any valuation is the obtaining of the fundamental value of the company, the residual
income model is applied to the Interbank company and the obtaining value is contrasted
through the Montecarlo simulation.Trabajo de investigació
Factores clave de la supervisión en la etapa de ejecución contractual de las Asociaciones Público-Privadas del sector transportes en el Perú
La presente investigación busca profundizar el estudio de las Asociaciones Público-
Privadas en el Perú desde el ámbito de la supervisión y con enfoque en el sector transportes. Para
ello, se toma como rama de la gestión a los Sistemas de Control de Gestión, cuyos estudios previos
están principalmente enfocados desde el sector privado, por lo que se analizan sus aristas
orientadas desde el sector público a pesar de las escasas investigaciones existentes al respecto.
Luego de ello, se identifican factores clave que determinan el buen desempeño de la
supervisión de las Asociaciones Público-Privadas, identificando su importancia y la problemática
que se deriva de ellos en la práctica. De tal manera, se agrupan nueve factores clave en el ámbito
de la supervisión según diversas investigaciones académicas.
A continuación, se diseña una guía de entrevistas semiestructurada como herramienta
cualitativa para corroborar los factores clave identificados con diecinueve expertos en la materia
pertenecientes a las diversas entidades participantes de las Asociaciones Público-Privadas en el
sector transportes de Perú.
Finalmente, producto del análisis de la información provista por los expertos y la
correspondiente corroboración con la teoría, se deriva en conclusiones que destacan los
principales hallazgos tomando en cuenta el contexto particular en el que se basa la investigación
y aportando así a los próximos proyectos que se implementen en el sector transportes o aquellos
que actualmente se encuentran en la etapa de ejecución contractual
Contact Lens-Associated Infectious Keratitis: Update on Diagnosis and Therapy
The focus of this chapter is to review the most recent advances in the diagnosis and treatment of contact-lens-related infectious keratitis, the most sight-threatening complication of contact lens wear. In the last decades, contact lenses technology has confronted several challenges, including the need for safer and more comfortable polymer materials. The development of high coefficient oxygen permeability (Dkt) and low-water content disposable contact lens translated into a significant improvement in ocular discomfort related to dry eye and allergic reactions, decreasing biofilm build-up on the external surface of the lens. Additionally, the emergence and boom-effect of corneal refractive surgery have also driven the development of better contact lens manufacturing. Despite these substantial technological advances, contact lens users continue to be at risk for developing corneal infections. We describe recent epidemiologic data, and advances in understanding the complex pathogenesis of the disease, including the clinical characteristics of the infectious process produced by bacteria, fungi, and protozoans. Finally, the recent development of diagnostic techniques and therapeutic regimens are discussed
A hybrid approach to boost the permutation index for similarity searching
We propose a hybrid strategy that combines three ideas, namely, a convenient way for reducing the length of the permutations, using a permutation similarity measure adjusted for these clipped permutations, and the use of the closest permutant of each object as a pivot for it. In this way, we increase the discriminability of the permutation index in order to reduce even more the number of distance computations without reducing the answer quality. The performance of our proposal is tested using two classical real-world databases: NASA and Colors which are part of the SISAP project’s metric space benchmark. We reduced more than 30% of the number of distance evaluations needed to solve the queries on both databases.XIX Workshop Base de Datos y Minería de Datos (WBDMD)Red de Universidades con Carreras en Informátic
PLANEACIÓN DIDÁCTICA GENERAL DE LA ASIGNATURA: ARITMÉTICA Y LENGUAJE MATEMÁTICO 2017B
GUÍA DIDÁCTICA / PLANEACIÓN DIDÁCTICA (NMS
PLANEACIÓN DIDÁCTICA GENERAL DE LA ASIGNATURA: TRIGONOMETRÍA 2017- B
GUÍA DIDÁCTICA / PLANEACIÓN DIDÁCTICA (NMS
Performance of the First ANTARES Detector Line
In this paper we report on the data recorded with the first Antares detector
line. The line was deployed on the 14th of February 2006 and was connected to
the readout two weeks later. Environmental data for one and a half years of
running are shown. Measurements of atmospheric muons from data taken from
selected runs during the first six months of operation are presented.
Performance figures in terms of time residuals and angular resolution are
given. Finally the angular distribution of atmospheric muons is presented and
from this the depth profile of the muon intensity is derived.Comment: 14 pages, 9 figure
Time calibration of the ANTARES neutrino telescope
The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of similar to 1 ns. The methods developed to attain this level of precision are described
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