The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Samuel Masket - One of the best experts on this subject based on the ideXlab platform.
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Simple Regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation
Journal of Cataract and Refractive Surgery, 2006Co-Authors: Samuel MasketAbstract:Purpose To develop a Simple and accurate method for determining appropriate intraocular lens (IOL) power in cataract patients who had prior excimer laser photoablation for myopia or hyperopia, because laser vision corrective surgery interferes with traditional keratometry and corneal topography, rendering IOL power calculations inaccurate. Setting Private Practice in Century City (Los Angeles), California, and free-standing outpatient surgery centers with institutional review boards. Methods Based on the empiric experience of the senior author, an IOL power correction factor that was proportional to the prior laser photoablation was determined and applied to the IOL power calculated by the IOLMaster (Zeiss). It was necessary to add to the predicted IOL power in eyes with prior myopic laser ablation, whereas eyes having prior hyperopic laser vision correction required a reduction in the IOL power. The correction factor was applied to 30 eyes that required cataract surgery at some time after laser refractive surgery; 23 eyes had prior treatment for myopia, and the remaining 7 eyes had prior hyperopic laser ablation. A Regression formula was generated from the IOL power correction factor that was used in the 30 eyes. Results Using the correction factor for 30 eyes, the mean deviation from the desired postcataract refractive outcome was −0.15 diopter (D) ± 0.29 (SD); 28 of 30 eyes were within ±0.5 D of the intended goal; the remaining 2 eyes were both −0.75 D from the desired optical result of cataract surgery. Fourteen of the 30 eyes were emmetropic. Conclusions A Simple IOL power corrective adjustment Regression formula allowed accurate determination of IOL power after laser refractive photoablation surgery. The weakness of the current method is that knowledge of the amount of prior laser vision correction is necessary.
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Simple Regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation.
Journal of cataract and refractive surgery, 2006Co-Authors: Samuel MasketAbstract:To develop a Simple and accurate method for determining appropriate intraocular lens (IOL) power in cataract patients who had prior excimer laser photoablation for myopia or hyperopia, because laser vision corrective surgery interferes with traditional keratometry and corneal topography, rendering IOL power calculations inaccurate. Private Practice in Century City (Los Angeles), California, and free-standing outpatient surgery centers with institutional review boards. Based on the empiric experience of the senior author, an IOL power correction factor that was proportional to the prior laser photoablation was determined and applied to the IOL power calculated by the IOLMaster (Zeiss). It was necessary to add to the predicted IOL power in eyes with prior myopic laser ablation, whereas eyes having prior hyperopic laser vision correction required a reduction in the IOL power. The correction factor was applied to 30 eyes that required cataract surgery at some time after laser refractive surgery; 23 eyes had prior treatment for myopia, and the remaining 7 eyes had prior hyperopic laser ablation. A Regression formula was generated from the IOL power correction factor that was used in the 30 eyes. Using the correction factor for 30 eyes, the mean deviation from the desired postcataract refractive outcome was -0.15 diopter (D) +/- 0.29 (SD); 28 of 30 eyes were within +/-0.5 D of the intended goal; the remaining 2 eyes were both -0.75 D from the desired optical result of cataract surgery. Fourteen of the 30 eyes were emmetropic. A Simple IOL power corrective adjustment Regression formula allowed accurate determination of IOL power after laser refractive photoablation surgery. The weakness of the current method is that knowledge of the amount of prior laser vision correction is necessary.
Paul E. Meehl - One of the best experts on this subject based on the ideXlab platform.
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Simple Regression-BASED PROCEDURES FOR TAXOMETRIC INVESTIGATIONS "
Psychological Reports, 1993Co-Authors: William M. Grove, Paul E. MeehlAbstract:Certain theories of psychopathology postulate the existence of distinct latent populations of individuals. By analogy with biology, we call such latent populations “taxa” and we call the statistica...
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Simple Regression-based procedures for taxometric investigations.
Psychological reports, 1993Co-Authors: William M. Grove, Paul E. MeehlAbstract:Certain theories of psychopathology postulate the existence of distinct latent populations of individuals. By analogy with biology, we call such latent populations "taxa" and we call the statistical testing of such theories "taxometrics." Taxometric procedures are robust; they do not make restrictive distributional assumptions. However, they have two disadvantages for nonstatistician users: (1) they are developed via algebra hard for many nonstatistician users intuitively to accept; and (2) computational software is not widely available. We address these problems by presenting a Simple taxometric procedure, MAXSLOPE, based on Regression plots for pairs of variables. This procedure is easily implemented using commonly available software and is intuitively rather easy to understand. We apply it to two artificial datasets. One dataset, used to explain the graphs, shows clear-cut evidence of taxa. The other example shows less clear grouping structure and is used to show that the proposed graphical procedure works even in nonideal cases. Comparisons are made with currently used procedures of cluster analysis and multivariate normal mixture analysis.
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Simple Regression-Based Procedures for Taxometric Investigations,2
Psychological Reports, 1993Co-Authors: William M. Grove, Paul E. MeehlAbstract:Certain theories of psychopathology postulate the existence of distinct latent populations of individuals. By analogy with biology, we call such latent populations “taxa” and we call the statistical testing of such theories “taxometrics.” Taxometric procedures are robust; they do not make restrictive distributional assumptions. However, they have two disadvantages for nonstatistician users: (1) they are developed via algebra hard for many nonstatistician users intuitively to accept; and (2) computational software is not widely available. We address these problems by presenting a Simple taxometric procedure, MAXSLOPE, based on Regression plots for pairs of variables. This procedure is easily implemented using commonly available software and is intuitively rather easy to understand. We apply it to two artificial datasets. One data-set, used to explain the graphs, shows clear-cut evidence of taxa. The other example shows less clear grouping structure and is used to show that the proposed graphical procedure works even in nonideal cases. Comparisons are made with currently used procedures of cluster analysis and multivariate normal mixture analysis.
Douglas R. Macayeal - One of the best experts on this subject based on the ideXlab platform.
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Ice stream basal conditions from block‐wise surface data inversion and Simple Regression models of ice stream flow: Application to Bindschadler Ice Stream
Journal of Geophysical Research, 2008Co-Authors: O. V. Sergienko, Robert Bindschadler, Patricia Vornberger, Douglas R. MacayealAbstract:[1] Widespread basal conditions controlling ice stream flows are still beyond the scope of direct observation, thus knowledge of their magnitudes and variabilities comes from inversion of surface measurements: ice velocities, surface elevations, and thicknesses. We present a new approach to implement a widely accepted inverse method on regular (10 × 10 km) blocks, smaller than the whole domain, to enhance the spatial resolution of calculated basal conditions. Inverted basal friction coefficients and calculated shear stress have sharp transitions and large variations in small areas. Overall, the obtained basal shear stress is very small in regions of fast flowing ice. The results of the inversion, along with the surface variables, are used to construct two Simple Regression models of Bindschadler Ice Stream (former Ice Stream D) that reproduce 96% of observed velocity variations. While highly idealized, these Regression models are sufficiently informative to be considered as parameterizations for ice stream flow in large-scale ice sheet models which lack the spatial and temporal resolution necessary to simulate ice stream dynamics in detail.
Karl W. Broman - One of the best experts on this subject based on the ideXlab platform.
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A Simple Regression-Based Method To Map Quantitative Trait Loci Underlying Function-Valued Phenotypes
Genetics, 2014Co-Authors: Il Youp Kwak, Candace R. Moore, Edgar P. Spalding, Karl W. BromanAbstract:Most statistical methods for quantitative trait loci (QTL) mapping focus on a single phenotype. However, multiple phenotypes are commonly measured, and recent technological advances have greatly simplified the automated acquisition of numerous phenotypes, including function-valued phenotypes, such as growth measured over time. While methods exist for QTL mapping with function-valued phenotypes, they are generally computationally intensive and focus on single-QTL models. We propose two Simple, fast methods that maintain high power and precision and are amenable to extensions with multiple-QTL models using a penalized likelihood approach. After identifying multiple QTL by these approaches, we can view the function-valued QTL effects to provide a deeper understanding of the underlying processes. Our methods have been implemented as a package for R, funqtl.
Sara Knott - One of the best experts on this subject based on the ideXlab platform.
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A Simple Regression method for mapping quantitative trait loci in line crosses using flanking markers.
Heredity, 1992Co-Authors: Chris Haley, Sara KnottAbstract:The use of flanking marker methods has proved to be a powerful tool for the mapping of quantitative trait loci (QTL) in the segregating generations derived from crosses between inbred lines. Methods to analyse these data, based on maximum-likelihood, have been developed and provide good estimates of QTL effects in some situations. Maximum-likelihood methods are, however, relatively complex and can be computationally slow. In this paper we develop methods for mapping QTL based on multiple Regression which can be applied using any general statistical package. We use the example of mapping in an F(2) population and show that these Regression methods produce very similar results to those obtained using maximum likelihood. The relative simplicity of the Regression methods means that models with more than a single QTL can be explored and we give examples of two lined loci and of two interacting loci. Other models, for example with more than two QTL, with environmental fixed effects, with between family variance or for threshold traits, could be fitted in a similar way. The ease, speed of application and generality of Regression methods for flanking marker analysis, and the good estimates they obtain, suggest that they should provide the method of choice for the analysis of QTL mapping data from inbred line crosses.
