Literatura académica sobre el tema "Optical indices"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Optical indices".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Artículos de revistas sobre el tema "Optical indices"
1
Rubin, M., K. von Rottkay, S. J. Wen, N. Özer y J. Slack. "Optical indices of lithiated electrochromic oxides". Solar Energy Materials and Solar Cells 54, n.º 1-4 (julio de 1998): 49–57. http://dx.doi.org/10.1016/s0927-0248(97)00222-5.
Texto completo
2
von Rottkay, K., M. Rubin y S. J. Wen. "Optical indices of electrochromic tungsten oxide". Thin Solid Films 306, n.º 1 (agosto de 1997): 10–16. http://dx.doi.org/10.1016/s0040-6090(97)00254-x.
Texto completo
3
Larouche, Stéphane y Ludvik Martinu. "Optical filters with prescribed optical thickness and refined refractive indices". Applied Optics 47, n.º 22 (28 de julio de 2008): 4140. http://dx.doi.org/10.1364/ao.47.004140.
Texto completo
4
Kosowski, Adrian. "Forwarding and optical indices of a graph". Discrete Applied Mathematics 157, n.º 2 (enero de 2009): 321–29. http://dx.doi.org/10.1016/j.dam.2008.03.002.
Texto completo
5
Shreve, Cheney M., Gregory S. Okin y Thomas H. Painter. "Indices for estimating fractional snow cover in the western Tibetan Plateau". Journal of Glaciology 55, n.º 192 (2009): 737–45. http://dx.doi.org/10.3189/002214309789470996.
Texto completoResumen
AbstractSnow cover in the Tibetan Plateau is highly variable in space and time and plays a key role in ecological processes of this cold-desert ecosystem. Resolution of passive microwave data is too low for regional-scale estimates of snow cover on the Tibetan Plateau, requiring an alternate data source. Optically derived snow indices allow for more accurate quantification of snow cover using higher-resolution datasets subject to the constraint of cloud cover. This paper introduces a new optical snow index and assesses four optically derived MODIS snow indices using Landsat-based validation scenes: MODIS Snow-Covered Area and Grain Size (MODSCAG), Relative Multiple Endmember Spectral Mixture Analysis (RMESMA), Relative Spectral Mixture Analysis (RSMA) and the normalized-difference snow index (NDSI). Pearson correlation coefficients were positively correlated with the validation datasets for all four optical snow indices, suggesting each provides a good measure of total snow extent. At the 95% confidence level, linear least-squares regression showed that MODSCAG and RMESMA had accuracy comparable to validation scenes. Fusion of optical snow indices with passive microwave products, which provide snow depth and snow water equivalent, has the potential to contribute to hydrologic and energy-balance modeling in the Tibetan Plateau.
6
Gasparri, D., L. Morelli, V. D. Ivanov, P. François, A. Pizzella, L. Coccato, E. M. Corsini, E. Dalla Bontà, L. Costantin y M. Cesetti. "Near-infrared spectroscopic indices for unresolved stellar populations – II. Index measurements". Monthly Notices of the Royal Astronomical Society 507, n.º 4 (24 de agosto de 2021): 4669–83. http://dx.doi.org/10.1093/mnras/stab2412.
Texto completoResumen
ABSTRACT We measured the equivalent width of a large set of near-infrared (NIR, 0.8–2.4$\ \mu$m) line-strength indices in XShooter medium-resolution spectra of the central regions of 14 galaxies. We found that two aluminum indices, Al at 1.31 μm and Al1 at 1.67 μm, and two CO indices, CO1 at 1.56 μm and CO4 at 1.64 μm, are tightly correlated with the velocity dispersion. Moreover, the NIR Al and CO1 indices show strong correlations with the optical Mg2 and Mgb indices, which are usually adopted as α/Fe-enhancement diagnostics. The molecular FeH1 index at 1.58 μm correlates tightly with the optical 〈Fe〉 and [MgFe]′ indices, which are used as total metallicity diagnostics. The NIR Paβ index at 1.28 μm has a behaviour similar to the optical Hβ index, which is a diagnostic of mean age. We defined two new composite indices, 〈Al〉 and [AlFeH], as possible candidates to be used as NIR diagnostics of total metallicity and α/Fe enhancement. The NIR 〈Al〉 index has a strong correlation with the optical Mg2 and Mgb indices, while the [AlFeH] index is tightly correlated with the optical 〈Fe〉 and [MgFe]′ indices. The distribution of the data points in the NIR Paβ–〈Al〉 and Paβ–[AlFeH] diagrams mimics that in the optical [MgFe]′–Hβ and Mgb–〈Fe〉 diagrams, which are widely used to constrain the properties of the unresolved stellar populations. We concluded that some NIR line-strength indices could be useful in studying stellar populations as well as in fine-tuning stellar population models.
7
Gil, José Jorge y Eusebio Bernabeu. "Depolarization and Polarization Indices of an Optical System". Optica Acta: International Journal of Optics 33, n.º 2 (febrero de 1986): 185–89. http://dx.doi.org/10.1080/713821924.
Texto completo
8
Qin, Fangli y R. K. Li. "Predicting refractive indices of the borate optical crystals". Journal of Crystal Growth 318, n.º 1 (marzo de 2011): 642–44. http://dx.doi.org/10.1016/j.jcrysgro.2010.08.037.
Texto completo
9
Rodríguez-Caballero, E., P. Escribano, C. Olehowski, S. Chamizo, J. Hill, Y. Cantón y B. Weber. "Transferability of multi- and hyperspectral optical biocrust indices". ISPRS Journal of Photogrammetry and Remote Sensing 126 (abril de 2017): 94–107. http://dx.doi.org/10.1016/j.isprsjprs.2017.02.007.
Texto completo
10
He, Yingran, Sailing He, Jie Gao y Xiaodong Yang. "Nanoscale metamaterial optical waveguides with ultrahigh refractive indices". Journal of the Optical Society of America B 29, n.º 9 (29 de agosto de 2012): 2559. http://dx.doi.org/10.1364/josab.29.002559.
Texto completoTesis sobre el tema "Optical indices"
1
Rao, S. Madhusudana. "Optical Metrology:Techniques For The Measurement Of Optical Parameters". Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/204.
Texto completoResumen
The work reported in this thesis has been carried out in the following two areas of Optical metrology:
1. Measurement and correction of prism angles
2. Measurement of refractive indices using a spectrograph.
The prism angles are conventionally tested by mechanical bevel protractors, autocol-limators (angle dekkors), simple interference techniques and interferometers.
All these methods have their own limitations either in accuracy or in terms of cost.
Mechanical methods are usually employed to measure the angles of prisms. Interference techniques and interferometers are also used but they need optically polished components. For both mechanical and simple interference methods of testing, it is essential to fabricate more than a single component in number. The process of building interferometers or purchasing interferometers, angle dekkors and standard angle gauges is not cost effective for many research laboratories, and medium scale industries. To overcome these difficulties simple and inexpensive methods without sacrificing the accuracy in the bargain are suggested for the measurement of prism angles, based on the principles of reflection of light.
The refractive indices of prism materials for invisible and weaker spectral lines are usually determined from spectrograms using dispersion formulae and numerical interpolation techniques. In these methods, the accuracy of the results depends on the accuracy of determining the constants of the dispersion formulae. A simple experimental technique, using a spectrograph, is devised for the measurement of refractive indices of solids and liquids both for visible and invisible spectral lines (wavelengths).
The thesis has been divided into six chapters.
The first chapter starts with the general introduction.
The second chapter presents the literature review of the existing methods for angle and refractive index measurements.
The third chapter describes the proposed new techniques for prism angle measurements.
The fourth chapter presents the experimental results of angle measurements, and the discussion of the accuracy of the results. This chapter also gives the scope for further research.
The fifth chapter describes a newly proposed technique for measuring refractive indices and the experimental results. This chapter also gives the scope for further research.
The summary of the results, conclusions, and suggestions for further work are presented in chapter six.
2
Rao, S. Madhusudana. "Optical Metrology:Techniques For The Measurement Of Optical Parameters". Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/204.
Texto completoResumen
The work reported in this thesis has been carried out in the following two areas of Optical metrology:
1. Measurement and correction of prism angles
2. Measurement of refractive indices using a spectrograph.
The prism angles are conventionally tested by mechanical bevel protractors, autocol-limators (angle dekkors), simple interference techniques and interferometers.
All these methods have their own limitations either in accuracy or in terms of cost.
Mechanical methods are usually employed to measure the angles of prisms. Interference techniques and interferometers are also used but they need optically polished components. For both mechanical and simple interference methods of testing, it is essential to fabricate more than a single component in number. The process of building interferometers or purchasing interferometers, angle dekkors and standard angle gauges is not cost effective for many research laboratories, and medium scale industries. To overcome these difficulties simple and inexpensive methods without sacrificing the accuracy in the bargain are suggested for the measurement of prism angles, based on the principles of reflection of light.
The refractive indices of prism materials for invisible and weaker spectral lines are usually determined from spectrograms using dispersion formulae and numerical interpolation techniques. In these methods, the accuracy of the results depends on the accuracy of determining the constants of the dispersion formulae. A simple experimental technique, using a spectrograph, is devised for the measurement of refractive indices of solids and liquids both for visible and invisible spectral lines (wavelengths).
The thesis has been divided into six chapters.
The first chapter starts with the general introduction.
The second chapter presents the literature review of the existing methods for angle and refractive index measurements.
The third chapter describes the proposed new techniques for prism angle measurements.
The fourth chapter presents the experimental results of angle measurements, and the discussion of the accuracy of the results. This chapter also gives the scope for further research.
The fifth chapter describes a newly proposed technique for measuring refractive indices and the experimental results. This chapter also gives the scope for further research.
The summary of the results, conclusions, and suggestions for further work are presented in chapter six.
3
Matsuda, Tatsuhito. "Optical Materials with High Refractive Indices Prepared by Copolymerization of Various Methacrylic Acid Esters". Kyoto University, 2000. http://hdl.handle.net/2433/151540.
Texto completo
4
Addis, James. "Optical properties of bent-core nematic liquid crystals". Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/optical-properties-of-bentcore-nematic-liquid-crystals(de6d40c5-a11f-4ae3-ab61-dbc55671d8b4).html.
Texto completoResumen
Much of the interest in bent-core compounds in the last few years has centred aroundtheir potential to form nematic liquid crystal phases, which may be both biaxial andpolar. These properties offer possibilities for nematic ferroelectric switching andnonlinear optics applications. In this work, two optical properties, the refractive indices and the second ordernonlinear optical response, were investigated in the high temperature (> 170 °C)nematic phase of a series of bent-core oxadiazole compounds, of varying chain typeand length. An experimental technique, based on the acquisition and analysis of reflectionspectra from liquid crystal cells, and capable of operating at the high temperaturesrequired, was used for the measurement of refractive indices. The extraordinaryrefractive index was found to range from 1.70 to 1.78 over the nematic phase of thebent-core compounds. The ordinary refractive index varied from 1.58 to 1.62. Bothranges of values are higher than is typically observed for rod-like liquid crystals. Thebirefringence took values from ~ 0.10, in the high temperature nematic phase, to~ 0.18, close to the underlying smectic phase. A new experiment was designed, constructed and tested for the second harmonic(SH) measurements. The dependences of the SH on temperature and on scatteringangle are well explained by the theory of SH generation by the flexoelectricpolarisation induced by thermal fluctuations of the director in the nematic phase. Themaximum conversion efficiency was measured to be very low, ~ 1/10000 of apercent. No evidence for the formation of macroscopic biaxial nematic phases was found byeither the refractive indices or SH experiments. However, for the compounds havinglong nematic phases of > 50 °C, different regimes of behaviour in the uniaxialnematic phase were revealed by the SH experiments. This atypical behaviour isconsistent with other reports on these compounds. This study cannot confirm the existence of nanoscale cybotactic clusters in thenematic phases of the bent-core compounds examined but neither is it inconsistentwith them.
5
Gao, Xiang. "Optical-biophysical relationships and validation of MODIS vegetation indices with multiple fine spatial resolution data in semiarid rangelands". Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279915.
Texto completoResumen
The vegetation index products from the Moderate Resolution Imaging Spectroradiometer (MODIS) are designed to provide consistent, spatial and temporal comparisons of global vegetation conditions. The objective of this dissertation was to validate the robustness and global implementation of two MODIS VI algorithms, including the normalized difference vegetation index (NDVI) and "enhanced" vegetation index (EVI). Their performances have been evaluated in: (1) the normalization of canopy background (brightness) variations and the extraction of biophysical parameters across different canopy structures; (2) the characterization of seasonal vegetation profiles (phenological, intra-annual); and (3) spatial and temporal discrimination of vegetation differences (inter-annual). The validation was accomplished through multiple means, including canopy radiative transfer models which were utilized to extract pure vegetation spectra and "true" VI value free of background contamination for varying canopy structures and vegetation amount. The experimental field- and airborne-based radiometry and satellite imagery at multiple spatial resolutions were also coupled and scaled-up for comparison with coarse spatial resolution MODIS VI products to quantify characteristics of semiarid rangeland vegetation. The results showed that NDVI was advantageous in yielding biophysical relationships applicable across varying canopy types, but required knowledge of soils for biophysical estimations. The EVI provided biophysical relationships sensitive to canopy structure, thus requiring knowledge of canopy type for biophysical assessments. The MODIS VI products were successfully validated, radiometrically, by coupling field and the MODLAND Quick Airborne Looks (MQUALS) observations to high spatial resolution imagery (AVIRIS and ETM+), and appeared robust across the two parallel sites for depicting their ecological equivalents. MODIS multitemporal VI profiles were able to depict phenological activity, length of the growing season, peak and onset of greenness, and leaf turnover. Among the sensors tested, spatial resolution was found to be most important for discriminating the major land cover subtypes within the two parallel semiarid rangelands, and spectral resolution had major effects on capturing seasonal contrast due to atmosphere influences. The validation strategy utilized in this study to successively aggregate the integrity-inherent multiple fine spatial resolution data to the coarse MODIS pixel sizes appeared to perform well, thus showing potentials in the validation of other satellite products.
6
Olson, Daniel O. "Relationship of Vegetation Indices from Drone-Based Passive Optical Sensors with Corn Grain Yield and Sugar Beet Root Yield and Quality". Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29887.
Texto completoResumen
The main goal of this study was to calibrate small unmanned aircraft system (SUAS) based vegetation indices with fertilizer-N application rate and yield for corn and sugar beet. It was hypothesized that canopy reflectance would change with increasing fertilizer-N application rates. The objectives of this study were (i) to determine the crop yield and quality in response to fertilizer application rates at two field sites, (ii) map vegetation indices of the experimental plots using drone-based optical sensors, and (iii) calibration of vegetation indices with crop yield. During 2017 and 2018 growing seasons, field trials were conducted to determine corn and sugar beet response to fertilizer-N application rates. In general, the use of optical sensors for quantitative and qualitative relationships were greater after the V6 growth stage in both corn and sugar beet. Early season moisture deficiency, disease, and crop size could impact the quality of the optical sensing data collection.
7
Briard, Paul. "Caractérisation 3D d’un nuage de particules par imagerie interférométrique de Fourier : positions relatives 3D, tailles et indices de réfraction". Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0023/document.
Texto completoResumen
Dans ce mémoire, je propose une nouvelle technique optique de mesure de positions relatives 3D, tailles et indices de réfraction d’un ensemble de particules, éclairées par un faisceau laser plan pulsé : l’imagerie interférométrique de Fourier (FII). Dans le cadre de ce travail, les particules sont sphériques, homogènes transparentes et isotropes. Lorsque ces particules sont éclairées, elles se comportent comme des sources d’ondes lumineuses sphériques qui interférent entre elles. L’enregistrement des franges d’interférences et leur analyse par transformation de Fourier peut permettre d’accéder aux caractéristiques des particules. Dans ce mémoire, je décris l’influence des caractéristiques de particules sur les représentations spectrales des franges d’interférences crées par les couples de particules éclairées dans l’espace de Fourier 2D. Les franges d’interférences sont simulées numériquement en utilisant la théorie de Lorenz-Mie. Puis j’aborde le problème inverse en montrant comment il est possible de retrouver les caractéristiques des particules, en me servant de l’optique géométrique et du filtrage spatial par transformation de FourierIn this thesis, I propose a new optical technique for measuring 3D relative positions, sizes and refractive indices of a set of particles, which are illuminated by a plane and pulsed laser beam. In this work, the particles are spherical, transparent, homogeneous and isotropic. When these particles are illuminated, they have the behavior of sources of spherical light waves which interfere. The recording of interference fringes and analysisby Fourier transform can measure the characteristics of the particles. I describe the influence of particle characteristics on spectral representations of the interference fringes created by the pairs of particles illuminated in 2D Fourier space. The interference fringes are simulated numerically using the Lorenz-Mietheory. The inverse problem is approached by showing how it is possible to measure the characteristics of particles with geometrical optics and spatial filtering by Fourier transformation
8
Charlet, Emilie. "Mouillage et orientation d’un film mince de cristal liquide colonnaire : de la détermination des propriétés optiques aux applications photovoltaïques". Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13653/document.
Texto completoResumen
Cette thèse est consacrée à l’étude de films minces ouverts de cristaux liquides colonnaires sur un substrat solide. Ces matériaux, capables de s’auto-organiser en de larges domaines orientés, sont généralement obtenus à partir de molécules discotiques dérivées de colorants aromatiques. Ces différentes caractéristiques, associées à une bonne mobilité de charges, permettent d'envisager l'utilisation des cristaux liquides colonnaires en film mince dans des dispositifs photovoltaïques. Afin de bénéficier de leurs bonnes propriétés optoélectroniques, les cristaux liquides colonnaires doivent être déposés en film mouillant, d’épaisseur inférieure à 100 nm, et leur orientation contrôlée. Ainsi, pour des applications photovoltaïques, un alignement homéotrope (colonnes normales au substrat) est requis. Inversement, l’orientation planaire uniaxe (colonnes parallèles au substrat), est quant à elle requise pour une utilisation de ces composés dans les polariseurs ou dans les transistors organiques à effet de champ. Dans ce travail, différentes méthodes permettant de contrôler l’alignement de films minces ouverts de cristaux liquides colonnaires ont été développées, permettant d’obtenir aussi bien un ancrage homéotrope par traitement thermique spécifique, qu’un ancrage planaire uniaxe par dépôt préalable d’une couche de téflon. Le contrôle de l’orientation a ainsi permis d’une part de produire un film mince (e ? 50 nm) mouillant en ancrage homéotrope ouvrant la voie vers des cellules solaires organiques efficaces, et d’autre part de déterminer l’ensemble des propriétés optiques (indices complexes anisotropes) de ces matériaux cristallins liquides colonnaires. La dynamique du démouillage et l’état d’équilibre d’un film mince ouvert de cristal liquide colonnaire ont également été étudiés. Les résultats expérimentaux révèlent la formation de gouttelettes anisotropes et la présence d’un film nanométrique lors du démouillage de ce film minceThis thesis deals with columnar liquid crystal studied in the geometry of open supported thin films. Columnar liquid crystals are usually made of disk-shaped molecules derived from aromatic dyes. They are efficient charge transporters with the added capacity to self-assemble in large oriented domains. Consequently, such materials may be used in photovoltaic devices. In order to benefit from their good uniaxial charge mobility, their organization has to be controlled in uniform oriented thin films in the range of thicknesses of typically 100 nm. Homeotropic alignment (columns normal to the interface) is required for solar cells whereas uniaxial planar anchoring (columns parallel to the interface) is needed for applications such as polarizers or organic field effect transistor. Different methods to monitor the alignment in open thin films have been developed in this work, which make possible to achieve either homeotropic anchoring by a specific thermal treatment, or uniaxial planar orientation using a Teflon layer. Based on these orientation skills, a uniform ultra-thin film, free of dewetting and homeotropically oriented, is achieved (down to 50 nm thick) opening the way towards efficient solar cells, and a complete study of the optical properties has been performed (with the determination of the anisotropic complex indices) for different columnar liquid crystals. The dynamics of dewetting and the equilibrium state of a thin supported film have also been investigated. Experimental results show the formation of anisotropic droplets and reveal a nanometric film during dewetting
9
Amazirh, Abdelhakim. "Monitoring crops water needs at high spatio-temporal resolution by synergy of optical/thermal and radar observations". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30101.
Texto completoResumen
L'optimisation de la gestion de l'eau en agriculture est essentielle dans les zones semi-arides afin de préserver les ressources en eau qui sont déjà faibles et erratiques dues à des actions humaines et au changement climatique. Cette thèse vise à utiliser la synergie des observations de télédétection multispectrales (données radar, optiques et thermiques) pour un suivi à haute résolution spatio-temporelle des besoins en eau des cultures. Dans ce contexte, différentes approches utilisant divers capteurs (Landsat-7/8, Sentinel-1 et MODIS) ont été developpées pour apporter une information sur l'humidité du sol (SM) et le stress hydrique des cultures à une échelle spatio-temporelle pertinente pour la gestion de l'irrigation. Ce travail va parfaitement dans le sens des objectifs du projet REC "Root zone soil moisture Estimates at the daily and agricultural parcel scales for Crop irrigation management and water use impact: a multi-sensor remote sensing approach" (http://rec.isardsat.com/) qui visent à estimer l'humidité du sol dans la zone racinaire (RZSM) afin d'optimiser la gestion de l'eau d'irrigation. Des approches innovantes et prometteuses sont mises en place pour estimer l'évapotranspiration (ET), RZSM, la température de surface du sol (LST) et le stress hydrique de la végétation à travers des indices de SM dérivés des observations multispectrales à haute résolution spatio-temporelle. Les méthodologies proposées reposent sur des méthodes basées sur l'imagerie, la modélisation du transfert radiatif et la modélisation du bilan hydrique et d'énergie et sont appliquées dans une région à climat semi-aride (centre du Maroc). Dans le cadre de ma thèse, trois axes ont été explorés. Dans le premier axe, un indice de RZSM dérivé de LST-Landsat est utilisé pour estimer l'ET sur des parcelles de blé et des sols nus. L'estimation par modélisation de ET a été explorée en utilisant l'équation de Penman-monteith modifiée obtenue en introduisant une relation empirique simple entre la résistance de surface (rc) et l'indice de RZSM. Ce dernier est estimé à partir de la température de surface (LST) dérivée de Landsat, combinée avec les températures extrêmes (en conditions humides et sèches) simulée par un modèle de bilan d'énergie de surface piloté par le forçage météorologique et la fraction de couverture végétale dérivée de Landsat. La méthode utilisée est calibrée et validée sur deux parcelles de blé situées dans la même zone près de Marrakech au Maroc. Dans l'axe suivant, une méthode permettant de récupérer la SM de la surface (0-5 cm) à une résolution spatiale et temporelle élevée est développée à partir d'une synergie entre données radar (Sentinel-1) et thermique (Landsat) et en utilisant un modèle de bilan d'énergie du sol. L'approche développée a été validée sur des parcelles agricoles en sol nu et elle donne une estimation précise de la SM avec une différence quadratique moyenne en comparant à la SM in situ, égale à 0,03 m3 m-3. Dans le dernier axe, une nouvelle méthode est développée pour désagréger la MODIS LST de 1 km à 100 m de résolution en intégrant le SM proche de la surface dérivée des données radar Sentinel-1 et l'indice de végétation optique dérivé des observations Landsat. Le nouvel algorithme, qui inclut la rétrodiffusion S-1 en tant qu'entrée dans la désagrégation, produit des résultats plus stables et robustes au cours de l'année sélectionnée. Dont, 3,35 °C était le RMSE le plus bas et 0,75 le coefficient de corrélation le plus élevé évalués en utilisant le nouvel algorithmeOptimizing water management in agriculture is essential over semi-arid areas in order to preserve water resources which are already low and erratic due to human actions and climate change. This thesis aims to use the synergy of multispectral remote sensing observations (radar, optical and thermal data) for high spatio-temporal resolution monitoring of crops water needs. In this context, different approaches using various sensors (Landsat-7/8, Sentinel-1 and MODIS) have been developed to provide information on the crop Soil Moisture (SM) and water stress at a spatio-temporal scale relevant to irrigation management. This work fits well the REC "Root zone soil moisture Estimates at the daily and agricultural parcel scales for Crop irrigation management and water use impact: a multi-sensor remote sensing approach" (http://rec.isardsat.com/) project objectives, which aim to estimate the Root Zone Soil Moisture (RZSM) for optimizing the management of irrigation water. Innovative and promising approaches are set up to estimate evapotranspiration (ET), RZSM, land surface temperature (LST) and vegetation water stress through SM indices derived from multispectral observations with high spatio-temporal resolution. The proposed methodologies rely on image-based methods, radiative transfer modelling and water and energy balance modelling and are applied in a semi-arid climate region (central Morocco). In the frame of my PhD thesis, three axes have been investigated. In the first axis, a Landsat LST-derived RZSM index is used to estimate the ET over wheat parcels and bare soil. The ET modelling estimation is explored using a modified Penman-Monteith equation obtained by introducing a simple empirical relationship between surface resistance (rc) and a RZSM index. The later is estimated from Landsat-derived land surface temperature (LST) combined with the LST endmembers (in wet and dry conditions) simulated by a surface energy balance model driven by meteorological forcing and Landsat-derived fractional vegetation cover. The investigated method is calibrated and validated over two wheat parcels located in the same area near Marrakech City in Morocco. In the next axis, a method to retrieve near surface (0-5 cm) SM at high spatial and temporal resolution is developed from a synergy between radar (Sentinel-1) and thermal (Landsat) data and by using a soil energy balance model. The developed approach is validated over bare soil agricultural fields and gives an accurate estimates of near surface SM with a root mean square difference compared to in situ SM equal to 0.03 m3 m-3. In the final axis a new method is developed to disaggregate the 1 km resolution MODIS LST at 100 m resolution by integrating the near surface SM derived from Sentinel-1 radar data and the optical-vegetation index derived from Landsat observations. The new algorithm including the S-1 backscatter as input to the disaggregation, produces more stable and robust results during the selected year. Where, 3.35 °C and 0.75 were the lowest RMSE and the highest correlation coefficient assessed using the new algorithm
10
Ferreira, Pena Do Amaral J. A. "Aspects of optimal sequential resource allocation". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370266.
Texto completoLibros sobre el tema "Optical indices"
1
Cannata, F. Indice di rifrazione adronico. Napoli: Bibliopolis, 1996.
Buscar texto completo
2
Anand, Rahul. Optimal price indices for targeting inflation under incomplete markets. Cambridge, MA: National Bureau of Economic Research, 2010.
Buscar texto completo
3
Drasgow, Fritz. Multi-test extensions of practical and optimal appropriateness indices. Brooks Air Force Base, Tex: Air Force Human Resources Laboratory, Air Force Systems Command, 1987.
Buscar texto completo
4
D, Palik Edward, ed. Handbook of optical constants of solids II. Boston: Academic Press, 1991.
Buscar texto completo
5
Joseph, George. India's journey towards excellence in building earth observation cameras. Chennai: Notion Press, 2016.
Buscar texto completo
6
Rütimann, Hans. Computerization project of the Archivo General de Indias, Seville, Spain: A report to the Commission on Preservation and Access. Washington, D.C: Commission on Preservation and Access, 1992.
Buscar texto completo
7
Nair, Uma. Darpan. Editado por Gallerie Nvya (New Delhi, India). New Delhi: Gallerie Nvya, 2007.
Buscar texto completo
8
Nair, Uma. Darpan. Editado por Gallerie Nvya (New Delhi, India). New Delhi: Gallerie Nvyā, 2007.
Buscar texto completo
9
Gallerie Nvya (New Delhi, India), ed. Darpan. New Delhi: Gallerie Nvya, 2007.
Buscar texto completo
10
Wohlfarth, Christian y Manfred Dieter Lechner. Optical Constants Vol. 47: Refractive Indices of Pure Liquids and Binary Liquid Mixtures. Springer Berlin / Heidelberg, 2008.
Buscar texto completoCapítulos de libros sobre el tema "Optical indices"
1
Choi, Eun Young y Min Kim. "Optical Coherence Tomography Angiography for Biomarker Indices in Diabetes". En Biomarkers in Diabetes, 777–89. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08014-2_39.
Texto completo
2
Choi, Eun Young y Min Kim. "Optical Coherence Tomography Angiography for Biomarker Indices in Diabetes". En Biomarkers in Diabetes, 1–14. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-81303-1_39-1.
Texto completo
3
Perc, Matjaž N. y Giuseppe T. Cirella. "Evaluating Green Infrastructure via Unmanned Aerial Systems and Optical Imagery Indices". En Sustainable Human–Nature Relations, 171–84. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3049-4_9.
Texto completo
4
Wang, Cheng Chi, Ming Jyi Jang y Yuan Hung Peng. "An Enhanced Common Path Interference Measurement Method for Optical Refractive Indices". En Optics Design and Precision Manufacturing Technologies, 86–91. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-458-8.86.
Texto completo
5
Aishah khairuzzaman, Noor, Hadzli Hashim, Noor Ezan abdullah, Mohd Suhaimi sulaiman, Azrie Faris mohd azmi y Ahmad Faiz mohd sampian. "A Fuzzy approach to categorizing ripeness of citrus suhuensis using selected optical indices". En Bioresources Technology in Sustainable Agriculture, 3–20. Waretown, NJ: Apple Academic Press, 2017.: Apple Academic Press, 2018. http://dx.doi.org/10.1201/9781315365961-1.
Texto completo
6
Zhu, Quanyan y Tamer Başar. "Indices of Power in Optimal IDS Default Configuration: Theory and Examples". En Lecture Notes in Computer Science, 7–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-25280-8_3.
Texto completo
7
Bassetti, D., Y. Brechet, G. Heiberg, I. Lingorski y P. Pechambert. "Genetic Algorithm and Performance Indices Applied to Optimal Design of Sandwich Structures". En Mechanics of Sandwich Structures, 387–95. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-015-9091-4_46.
Texto completo
8
Zhang, Jun, Bing Wang y Xiang Zhang. "Optimal Selection of Support Vector Regression Parameters and Molecular Descriptors for Retention Indices Prediction". En Advanced Intelligent Computing Theories and Applications. With Aspects of Artificial Intelligence, 83–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14932-0_11.
Texto completo
9
Marie-Sainte, Souad Larabi, Alain Berro y Anne Ruiz-Gazen. "An Efficient Optimization Method for Revealing Local Optima of Projection Pursuit Indices". En Lecture Notes in Computer Science, 60–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-15461-4_6.
Texto completo
10
Mance, Davor, Diana Mance y Darija Vukić Lušić. "Managing water commons using mediator variables to bridge the gap between environmental factors and anthropogenic pollution indicators". En Ninth International Symposium “Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques”, 515–24. Florence: Firenze University Press, 2022. http://dx.doi.org/10.36253/979-12-215-0030-1.47.
Texto completoResumen
Data analysis of groundwater dynamics requires dynamic panel data modelling. Static models that include δ18O values successfully represent the microbial pollution variations within a closed system characteristic of stock pollution. The need for dynamic modelling using first differences of δ18O values indicates that we deal with flow pollution. Policies regarded as optimal for stock and flow pollutants are different. The question of stock or flow is of great importance to decide whether the regulatory body should use price or quantitative allocation mechanisms.
Actas de conferencias sobre el tema "Optical indices"
1
Chai, L., J. Shi, L. Zhang y T. Jackson. "Refinement of microwave vegetation indices". En SPIE Optical Engineering + Applications, editado por Wei Gao, Thomas J. Jackson y Jinnian Wang. SPIE, 2010. http://dx.doi.org/10.1117/12.858356.
Texto completo
2
Stehle, J. L., A. Toussaere y J. Ziss. "Nonlinear Optical Coating Indices and Thickness Measured by Spectroscopic Ellipsometry". En Optical Interference Coatings. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oic.1992.othe1.
Texto completo
3
Jackson, T. J., J. C. Shi y J. Tao. "Microwave vegetation indices derived from satellite microwave radiometers". En Optical Engineering + Applications, editado por Wei Gao y Hao Wang. SPIE, 2008. http://dx.doi.org/10.1117/12.790529.
Texto completo
4
Gang, Jin, J. P. Roger, A. C. Boccara y J. L. Stehle. "Characterization of Dynamic Indices by Stimulated Spectroscopic Ellipsometry". En Optical Interference Coatings. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oic.1992.othe4.
Texto completoResumen
Dynamic indices of multilayer structures can be extracted from stimulated spectroscopic ellipsometry. Using pulsed laser excitation, various heat diffusion processes through the structure can be separated.
5
Amra, Claude, Boris Gralak, Sebastien Guenneau, Myriam Zerrad y Michel Lequime. "Negative indices and the admittance formalism in multilayer optics". En Optical Interference Coatings. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/oic.2013.tb.9.
Texto completo
6
Liu, Hao, Yunti Pu, Zhao Qiao, Singlin Chen, Yaowei Wei, Zhe Zhang, Sheng Ouyang et al. "Ion Beam Sputtered Mixture Films with Tailored Refractive Indices". En Optical Interference Coatings. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/oic.2013.wd.8.
Texto completo
7
Horowitz, F. y H. A. Macleod. "Determination of Principal Refractive Indices of Birefringent Thin Films". En Optical Interference Coatings. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oic.1988.wc11.
Texto completoResumen
Discriminatory optical behavior of obliquely deposited films with respect to the polarization of light has been known for about a century.1 Although scarce, reports on this effect can be found in the literature from the early2-5 and mid6-8 1900's. More recently, metal films were used as polarizers in the near-infrared9 and dielectric films were shown to perform as phase-retarders in the visible.10 Those are two different manifestations of structure-induced optical anisotropy in connection with significant asymmetries in extinction coefficient and refractive index valves, respectively.10
8
Šimon, V. "Color indices of optical afterglows of GRBs". En The fifth huntsville gamma-ray burst symposium. AIP, 2000. http://dx.doi.org/10.1063/1.1361556.
Texto completo
9
Wang, Suzhen, Jingjing Luo, Yuan-Hsun Lo y Wing Shing Wong. "Forwarding and Optical Indices in an All-Optical BCube Networks". En 2018 IEEE 37th International Performance Computing and Communications Conference (IPCCC). IEEE, 2018. http://dx.doi.org/10.1109/pccc.2018.8711077.
Texto completo
10
Larouche, Stephane y Ludvik Martinu. "Optical Filters with Constant Optical Thickness and Refined Refractive Indices". En Optical Interference Coatings. Washington, D.C.: OSA, 2007. http://dx.doi.org/10.1364/oic.2007.tud8.
Texto completoInformes sobre el tema "Optical indices"
1
Anand, Rahul y Eswar Prasad. Optimal Price Indices for Targeting Inflation Under Incomplete Markets. Cambridge, MA: National Bureau of Economic Research, agosto de 2010. http://dx.doi.org/10.3386/w16290.
Texto completo
2
Anilkumar, Rahul, Benjamin Melone, Michael Patsula, Christopher Tran, Christopher Wang, Kevin Dick, Hoda Khalil y G. A. Wainer. Canadian jobs amid a pandemic : examining the relationship between professional industry and salary to regional key performance indicators. Department of Systems and Computer Engineering, Carleton University, junio de 2022. http://dx.doi.org/10.22215/dsce/220608.
Texto completoResumen
The COVID-19 pandemic has contributed to massive rates of unemployment and greater uncertainty in the job market. There is a growing need for data-driven tools and analyses to better inform the public on trends within the job market. In particular, obtaining a “snapshot” of available employment opportunities mid-pandemic promises insights to inform policy and support retraining programs. In this work, we combine data scraped from the Canadian Job Bank and Numbeo globally crowd-sourced repository to explore the relationship between job postings during a global pandemic and Key Performance Indicators (e.g. quality of life index, cost of living) for major cities across Canada. This analysis aims to help Canadians make informed career decisions, collect a “snapshot” of the Canadian employment opportunities amid a pandemic, and inform job seekers in identifying the correct fit between the desired lifestyle of a city and their career. We collected a new high-quality dataset of job postings from jobbank.gc.ca obtained with the use of ethical web scraping and performed exploratory data analysis on this dataset to identify job opportunity trends. When optimizing for average salary of job openings with quality of life, affordability, cost of living, and traffic indices, it was found that Edmonton, AB consistently scores higher than the mean, and is therefore an attractive place to move. Furthermore, we identified optimal provinces to relocate to with respect to individual skill levels. It was determined that Ajax, Marathon, and Chapleau, ON are each attractive cities for IT professionals, construction workers, and healthcare workers respectively when maximizing average salary. Finally, we publicly release our scraped dataset as a mid-pandemic snapshot of Canadian employment opportunities and present a public web application that provides an interactive visual interface that summarizes our findings for the general public and the broader research community.
3
McCausland, Rachel, Joann Fontanarosa y Ravi Patel. Nonemergent Percutaneous Coronary Intervention Versus Optimal Medical Treatment for Stable Ischemic Heart Disease: A Rapid Response Literature Review. Agency for Healthcare Research and Quality (AHRQ), agosto de 2023. http://dx.doi.org/10.23970/ahrqepcrapidcoronary.
Texto completoResumen
Aims. There is uncertainty around the optimal role of percutaneous coronary intervention (PCI) for management of chronic coronary syndrome, specifically when patients have disease in multiple coronary vessels and disease in the proximal portion of the left anterior descending coronary artery. This uncertainty was reflected in 2021 guidance from the American College of Cardiology (ACC)/American Heart Association (AHA) on coronary artery revascularization. The Agency for Healthcare Research and Quality has commissioned this rapid response literature review to meet a Congressional request for a summary of recent evidence on the benefits of angioplasties conducted in nonemergency situations. Methods. This rapid response literature review on the comparative effectiveness of nonemergent PCI followed established best systematic review methods, modified to meet a shortened project timeframe. We searched PubMed®, Embase®, and the Trip© medical database from 2018 through April 2023 for systematic reviews (SRs), clinical practice guidelines, and randomized controlled trials, and summarized the evidence comparing PCI to optimal medical therapy (OMT) for stable ischemic heart disease (SIHD). Our primary outcomes of interest were major objective cardiovascular outcomes, including mortality, myocardial infarction, stroke, urgent revascularization, or composites of one or more of these hard clinical outcomes. Where available, we also abstracted patient reported outcomes (e.g., angina severity and quality of life [QoL]) from included studies. Findings. Key findings from nine SRs and one primary study include: • The body of evidence directly comparing PCI to OMT for SIHD has remained largely unchanged since the 2021 ACC/AHA guidance’s publication. • Most studies of revascularization for coronary artery disease do not focus on direct head-to-head comparisons of PCI versus OMT for SIHD but instead either (1) compare OMT to invasive revascularization (PCI and coronary artery bypass graft [CABG] combined cohort); (2) compare PCI to CABG; or (3) compare different PCI techniques. • Another factor that complicates comparison is that the meta-analyses often included data from CABG and PCI combined cohorts (e.g., the recent landmark ISCHEMIA trial) but reported the outcomes as PCI specific. • In the general SIHD population, our review did not find evidence to support survival benefit or effect on hard clinical outcomes when PCI is added to OMT. • Limited evidence indicates there may be a beneficial effect of PCI on angina symptoms and measures of QoL, but most systematic reviews focused on major objective cardiovascular outcomes and did not consider QoL or freedom from angina. • Both OMT and PCI have evolved significantly during the period of time in which the systematic reviews’ included studies were conducted. It is not clear how these changes may have affected the applicability of past studies to current practice. Conclusions. The evidence directly comparing PCI to OMT for SIHD has remained largely unchanged since publication of the 2021 ACC/AHA guidelines. More research is needed to verify the comparative effectiveness of nonemergent PCI compared to medical treatment for individuals with SIHD, and how the effectiveness varies by certain patient populations and clinical presentation.
4
Blum, Abraham y Henry T. Nguyen. Molecular Tagging of Drought Resistance in Wheat: Osmotic Adjustment and Plant Productivity. United States Department of Agriculture, noviembre de 2002. http://dx.doi.org/10.32747/2002.7580672.bard.
Texto completoResumen
Drought stress is a major limitation to bread wheat (Triticumaestivum L.) productivity and its yield stability in arid and semi-arid regions of world including parts of Israel and the U.S. Currently, breeding for sustained yields under drought stress is totally dependent on the use of yield and several key physiological attributes as selection indices. The attempt to identify the optimal genotype by evaluating the phenotype is undermining progress in such breeding programs. Osmotic adjustment (OA) is an effective drought resistance mechanism in many crop plants. Evidence exists that there is a genetic variation for OA in wheat and that high OA capacity supports wheat yields under drought stress. The major objective of this research was to identify molecular markers (RFLPs, restriction fragment length polymorphisms; and AFLPs, amplified fragment length polymorph isms) linked to OA as a major attribute of drought resistance in wheat and thus to facilitate marker-assisted selection for drought resistance. We identified high and low OA lines of wheat and from their cross developed recombinant inbred lines (RILs) used in the molecular tagging of OA in relation to drought resistance in terms of plant production under stress. The significant positive co-segregation of OA, plant water status and yield under stress in this RIL population provided strong support for the important role of OA as a drought resistance mechanism sustaining wheat production under drought stress. This evidence was obtained in addition to the initial study of parental materials for constructing this RIL population, which also gave evidence for a strong correlation between OA and grain yield under stress. This research therefore provides conclusive evidence on the important role of OA in sustaining wheat yield under drought stress. The measurement of OA is difficult and the selection for drought resistance by the phenotypic expression of OA is practically impossible. This research provided information on the genetic basis of OA in wheat in relations to yield under stress. It provided the basic information to indicate that molecular marker assisted selection for OA in wheat is possible. The RIL population has been created by a cross between two agronomic spring wheat lines and the high OA recombinants in this population presented very high OA values, not commonly observed in wheat. These recombinants are therefore an immediate valuable genetic recourse for breeding well-adapted drought resistant wheat in Texas and Israel. We feel that this work taken as a whole eliminate the few previous speculated . doubts about the practical role of OA as an important mechanism of drought resistance in economic crop plants. As such it should open the way, in terms of both concept and the use of marker assisted selection, for improving drought resistance in wheat by deploying high osmotic adjustment.
5
Dahl, Geoffrey E., Sameer Mabjeesh, Thomas B. McFadden y Avi Shamay. Environmental manipulation during the dry period of ruminants: strategies to enhance subsequent lactation. United States Department of Agriculture, febrero de 2006. http://dx.doi.org/10.32747/2006.7586544.bard.
Texto completoResumen
The project resulted from earlier observations that environmental factors, especially photoperiod and temperature, had profound effects on milk yield in dairy cattle during lactation. More recently we had determined that photoperiod manipulation during the dry period altered milk yield in the next lactation, and this was associated with shifts in circulating concentrations of prolactin; specifically exposure to short days during the dry period decreases prolactin but increases milk yield. Because prolactin is also affected by temperature, with heat stress causing an increase in prolactin similar to that of long day exposure, we focused our efforts on determining prolactin signaling provides a common pathway for generation of environmental effects on mammary growth, development and subsequent function during the dry period of dairy ruminants. Over the project period we made significant progress toward testing our hypotheses that (I): In cows, there is a discrete duration of time during the dry period in which exposure to short days will result in optimal enhancement of mammary development and milk yield in the following lactation, and that this effect is mediated through demonstrable changes in mammary gland development, prolactin signaling, and mammary gene expression; and (II): Modulation of photoperiod and temperature during the dry period will affect milk yield in goats in the subsequent lactation via shifts in nutrient and endocrine partitioning, and mammary gene expression, during the dry period and into lactation. Cows exposed to short days for only the final 21 days of the dry period did not produce more milk that those on long day or natural photoperiod when dry. However, cows on short days for the entire 60 days dry did produce more milk than the other 3 groups. This indicates that there is a duration effect of short day exposure on subsequent milk yield. Results of the second study in cows indicate that mammary growth increases differentially during the dry period under long vs. short days, and that short days drive more extensive growth which is associated with altered prolactin signaling via decreases in an suppressors of cytokine signaling that represent an inhibitory pathway to mammary growth. Evidence from the studies in Israel confirms that goats respond to short days during the dry period in a similar manner to cows. In addition, heat stress effects on during the dry period can be limited by exposure to short days. Here again, shifts in prolactin signaling, along with changes in IGF-I secretion, are associated with the observed changes in mammary function in goats. These results have a number of biological and practical implications. For dairy producers, it is clear that we can recommend that cows and goats should be on reduced light exposure during the dry period, and further, cows and goats should be cooled to avoid heat stress during that time. Environmental influences on mammary growth are apparent during the dry period, and those effects have persistent impact in the subsequent lactation. Prolactin signaling is a consistent mechanism whereby extended light exposure and heat stress may depress mammary growth and development during the dry period. Thus, the prolactin signaling system offers an opportunity for further manipulation to improve production efficiency in dairy ruminants.
6
Shomer, Ilan, Louise Wicker, Uzi Merin y William L. Kerr. Interactions of Cloud Proteins, Pectins and Pectinesterases in Flocculation of Citrus Cloud. United States Department of Agriculture, febrero de 2002. http://dx.doi.org/10.32747/2002.7580669.bard.
Texto completoResumen
The overall objective was to understand the cloud flocculation of citrus juice by characterization of the interactions between proteins and pectins, and to determine the role of PE isozymes in catalyzing this phenomenon. Specific objectives were to: 1. identify/characterize cloud-proteins in relation to their coagulable properties and affinity to pectins; 2. to determine structural changes of PME and other proteins induced by cation/pectin interactions; 3. localize cloud proteins, PME and bound protein/pectates in unheated and pasteurized juices; 4. to create "sensitized" pectins and determine their effect on clarification. The original objectives were not changed but the methods and approach were modified due to specific research requirements. Two i postulates were: 1. there is a specific interaction of cloud proteins with de-esterified regions of ! pectin and this contributes to cloud loss; 2. isozymes of pectin-methyl-esterase (PME) vary in efficiency to create sensitized pectins. The appearance of citrus fruit juice is an important quality factor and is determined by the color and turbidity that .are conferred by the suspended particles, i.e., by the cloud and its homogeneity. Under some circumstances the cloud tend to flocculate and the juice clarifies. The accepted approach to explain the clarification is based on pectin demethoxylation by PME that promotes formation of Ca-pectate. Therefore, the juice includes immediate heat-inactivation upon ~ squeezing. Protein coagulation also promotes cloud instability of citrus fruit extracts. However, the clarification mechanism is not fully understood. Information accumulated from several laboratories indicates that clarification is a more complex process than can be explained by a single mechanism. The increasing trend to consume natural-fresh juice emphasizing the importance of the knowledge to assure homogeneity of fresh juice. The research included complementary directions: Conditions that induce cloud-instability of natural- juice [IL]. Evaluate purification schemes of protein [USA]. Identifications of proteins, pectin and neutral sugars ([IL]; Structure of the cloud components using light and electron microscopy and immuno-labeling of PME, high-methoxyl-pectin (HMP) and low-methoxyl-pectin (LMP); Molecular weight of calcium sensitized pectins [US]; Evaluation of the products of PME activity [US]. Fractions and size distribution and cloud components [IL-US]. The optimal pH activity of PME is 7 and the flocculation pH of the cloud is 3-4. Thus, the c roles of PME, proteins and pectins in the cloud instability, were studied in pH ranges of 2- 7. The experiments led to establish firstly repeatable simulate conditions for cloud instability [IL]. Thermostable PME (TS-PE) known to induce cloud instability, but also thermolabile forms of PME (TL-PE) caused clarification, most likely due to the formation and dissolution of inactive :. PE-pectin complexes and displacement of a protective colloid from the cloud surface [US]. Furthermore, elimination of non-PME protein increases TS-PE activity, indicating that non-PME proteins moderate PME activity [US]. Other experiments Concomitantly with the study of the PME activity but promotes the association of cloud-proteins to pectin. Adjusting of the juice pH to f 7 retains the cloud stability and re-adjusting of the pH to 40% DE reacts to immuno-labeling in the cloud fragments, whereas
7
Rankin, Nicole, Deborah McGregor, Candice Donnelly, Bethany Van Dort, Richard De Abreu Lourenco, Anne Cust y Emily Stone. Lung cancer screening using low-dose computed tomography for high risk populations: Investigating effectiveness and screening program implementation considerations: An Evidence Check rapid review brokered by the Sax Institute (www.saxinstitute.org.au) for the Cancer Institute NSW. The Sax Institute, octubre de 2019. http://dx.doi.org/10.57022/clzt5093.
Texto completoResumen
Background Lung cancer is the number one cause of cancer death worldwide.(1) It is the fifth most commonly diagnosed cancer in Australia (12,741 cases diagnosed in 2018) and the leading cause of cancer death.(2) The number of years of potential life lost to lung cancer in Australia is estimated to be 58,450, similar to that of colorectal and breast cancer combined.(3) While tobacco control strategies are most effective for disease prevention in the general population, early detection via low dose computed tomography (LDCT) screening in high-risk populations is a viable option for detecting asymptomatic disease in current (13%) and former (24%) Australian smokers.(4) The purpose of this Evidence Check review is to identify and analyse existing and emerging evidence for LDCT lung cancer screening in high-risk individuals to guide future program and policy planning. Evidence Check questions This review aimed to address the following questions: 1. What is the evidence for the effectiveness of lung cancer screening for higher-risk individuals? 2. What is the evidence of potential harms from lung cancer screening for higher-risk individuals? 3. What are the main components of recent major lung cancer screening programs or trials? 4. What is the cost-effectiveness of lung cancer screening programs (include studies of cost–utility)? Summary of methods The authors searched the peer-reviewed literature across three databases (MEDLINE, PsycINFO and Embase) for existing systematic reviews and original studies published between 1 January 2009 and 8 August 2019. Fifteen systematic reviews (of which 8 were contemporary) and 64 original publications met the inclusion criteria set across the four questions. Key findings Question 1: What is the evidence for the effectiveness of lung cancer screening for higher-risk individuals? There is sufficient evidence from systematic reviews and meta-analyses of combined (pooled) data from screening trials (of high-risk individuals) to indicate that LDCT examination is clinically effective in reducing lung cancer mortality. In 2011, the landmark National Lung Cancer Screening Trial (NLST, a large-scale randomised controlled trial [RCT] conducted in the US) reported a 20% (95% CI 6.8% – 26.7%; P=0.004) relative reduction in mortality among long-term heavy smokers over three rounds of annual screening. High-risk eligibility criteria was defined as people aged 55–74 years with a smoking history of ≥30 pack-years (years in which a smoker has consumed 20-plus cigarettes each day) and, for former smokers, ≥30 pack-years and have quit within the past 15 years.(5) All-cause mortality was reduced by 6.7% (95% CI, 1.2% – 13.6%; P=0.02). Initial data from the second landmark RCT, the NEderlands-Leuvens Longkanker Screenings ONderzoek (known as the NELSON trial), have found an even greater reduction of 26% (95% CI, 9% – 41%) in lung cancer mortality, with full trial results yet to be published.(6, 7) Pooled analyses, including several smaller-scale European LDCT screening trials insufficiently powered in their own right, collectively demonstrate a statistically significant reduction in lung cancer mortality (RR 0.82, 95% CI 0.73–0.91).(8) Despite the reduction in all-cause mortality found in the NLST, pooled analyses of seven trials found no statistically significant difference in all-cause mortality (RR 0.95, 95% CI 0.90–1.00).(8) However, cancer-specific mortality is currently the most relevant outcome in cancer screening trials. These seven trials demonstrated a significantly greater proportion of early stage cancers in LDCT groups compared with controls (RR 2.08, 95% CI 1.43–3.03). Thus, when considering results across mortality outcomes and early stage cancers diagnosed, LDCT screening is considered to be clinically effective. Question 2: What is the evidence of potential harms from lung cancer screening for higher-risk individuals? The harms of LDCT lung cancer screening include false positive tests and the consequences of unnecessary invasive follow-up procedures for conditions that are eventually diagnosed as benign. While LDCT screening leads to an increased frequency of invasive procedures, it does not result in greater mortality soon after an invasive procedure (in trial settings when compared with the control arm).(8) Overdiagnosis, exposure to radiation, psychological distress and an impact on quality of life are other known harms. Systematic review evidence indicates the benefits of LDCT screening are likely to outweigh the harms. The potential harms are likely to be reduced as refinements are made to LDCT screening protocols through: i) the application of risk predication models (e.g. the PLCOm2012), which enable a more accurate selection of the high-risk population through the use of specific criteria (beyond age and smoking history); ii) the use of nodule management algorithms (e.g. Lung-RADS, PanCan), which assist in the diagnostic evaluation of screen-detected nodules and cancers (e.g. more precise volumetric assessment of nodules); and, iii) more judicious selection of patients for invasive procedures. Recent evidence suggests a positive LDCT result may transiently increase psychological distress but does not have long-term adverse effects on psychological distress or health-related quality of life (HRQoL). With regards to smoking cessation, there is no evidence to suggest screening participation invokes a false sense of assurance in smokers, nor a reduction in motivation to quit. The NELSON and Danish trials found no difference in smoking cessation rates between LDCT screening and control groups. Higher net cessation rates, compared with general population, suggest those who participate in screening trials may already be motivated to quit. Question 3: What are the main components of recent major lung cancer screening programs or trials? There are no systematic reviews that capture the main components of recent major lung cancer screening trials and programs. We extracted evidence from original studies and clinical guidance documents and organised this into key groups to form a concise set of components for potential implementation of a national lung cancer screening program in Australia: 1. Identifying the high-risk population: recruitment, eligibility, selection and referral 2. Educating the public, people at high risk and healthcare providers; this includes creating awareness of lung cancer, the benefits and harms of LDCT screening, and shared decision-making 3. Components necessary for health services to deliver a screening program: a. Planning phase: e.g. human resources to coordinate the program, electronic data systems that integrate medical records information and link to an established national registry b. Implementation phase: e.g. human and technological resources required to conduct LDCT examinations, interpretation of reports and communication of results to participants c. Monitoring and evaluation phase: e.g. monitoring outcomes across patients, radiological reporting, compliance with established standards and a quality assurance program 4. Data reporting and research, e.g. audit and feedback to multidisciplinary teams, reporting outcomes to enhance international research into LDCT screening 5. Incorporation of smoking cessation interventions, e.g. specific programs designed for LDCT screening or referral to existing community or hospital-based services that deliver cessation interventions. Most original studies are single-institution evaluations that contain descriptive data about the processes required to establish and implement a high-risk population-based screening program. Across all studies there is a consistent message as to the challenges and complexities of establishing LDCT screening programs to attract people at high risk who will receive the greatest benefits from participation. With regards to smoking cessation, evidence from one systematic review indicates the optimal strategy for incorporating smoking cessation interventions into a LDCT screening program is unclear. There is widespread agreement that LDCT screening attendance presents a ‘teachable moment’ for cessation advice, especially among those people who receive a positive scan result. Smoking cessation is an area of significant research investment; for instance, eight US-based clinical trials are now underway that aim to address how best to design and deliver cessation programs within large-scale LDCT screening programs.(9) Question 4: What is the cost-effectiveness of lung cancer screening programs (include studies of cost–utility)? Assessing the value or cost-effectiveness of LDCT screening involves a complex interplay of factors including data on effectiveness and costs, and institutional context. A key input is data about the effectiveness of potential and current screening programs with respect to case detection, and the likely outcomes of treating those cases sooner (in the presence of LDCT screening) as opposed to later (in the absence of LDCT screening). Evidence about the cost-effectiveness of LDCT screening programs has been summarised in two systematic reviews. We identified a further 13 studies—five modelling studies, one discrete choice experiment and seven articles—that used a variety of methods to assess cost-effectiveness. Three modelling studies indicated LDCT screening was cost-effective in the settings of the US and Europe. Two studies—one from Australia and one from New Zealand—reported LDCT screening would not be cost-effective using NLST-like protocols. We anticipate that, following the full publication of the NELSON trial, cost-effectiveness studies will likely be updated with new data that reduce uncertainty about factors that influence modelling outcomes, including the findings of indeterminate nodules. Gaps in the evidence There is a large and accessible body of evidence as to the effectiveness (Q1) and harms (Q2) of LDCT screening for lung cancer. Nevertheless, there are significant gaps in the evidence about the program components that are required to implement an effective LDCT screening program (Q3). Questions about LDCT screening acceptability and feasibility were not explicitly included in the scope. However, as the evidence is based primarily on US programs and UK pilot studies, the relevance to the local setting requires careful consideration. The Queensland Lung Cancer Screening Study provides feasibility data about clinical aspects of LDCT screening but little about program design. The International Lung Screening Trial is still in the recruitment phase and findings are not yet available for inclusion in this Evidence Check. The Australian Population Based Screening Framework was developed to “inform decision-makers on the key issues to be considered when assessing potential screening programs in Australia”.(10) As the Framework is specific to population-based, rather than high-risk, screening programs, there is a lack of clarity about transferability of criteria. However, the Framework criteria do stipulate that a screening program must be acceptable to “important subgroups such as target participants who are from culturally and linguistically diverse backgrounds, Aboriginal and Torres Strait Islander people, people from disadvantaged groups and people with a disability”.(10) An extensive search of the literature highlighted that there is very little information about the acceptability of LDCT screening to these population groups in Australia. Yet they are part of the high-risk population.(10) There are also considerable gaps in the evidence about the cost-effectiveness of LDCT screening in different settings, including Australia. The evidence base in this area is rapidly evolving and is likely to include new data from the NELSON trial and incorporate data about the costs of targeted- and immuno-therapies as these treatments become more widely available in Australia.