Linear Modelling of Pearson's Product Moment Correlation Coefficient: An Application of Fisher's z-Transformation

Bartlett, Roy F.

doi:10.2307/2348110

Cited by 25 publications

(23 citation statements)

References 7 publications

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“…P values of less than 0.05 were considered statistically significant. For correlation analyses, a Pearson product-moment correlation coefficient (r) calculation to evaluate the strength of the association was used with the strength of the association identified as not, weakly, moderately or strongly correlated for 0.0 ≤ r ≤ 0.2, 0.2 ≤ r ≤ 0.4, 0.4 ≤ r ≤ 0.6, and 0.6 ≤ r ≤ 1.0, respectively (Bartlett, 1993, Burroughs et al, 2011). Prism v5.0 software (Graphpad Software Inc., La Jolla, CA) was used for statistical analysis.…”

Section: Methodsmentioning

confidence: 99%

Differential up-regulation of Vesl-1/Homer 1 protein isoforms associated with decline in visual performance in a preclinical glaucoma model

et al. 2014

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Glaucoma is a multifactorial progressive ocular pathology, clinically presenting with damage to the retina and optic nerve, ultimately leading to blindness. Retinal ganglion cell loss in glaucoma ultimately results in vision loss. Vesl/Homer proteins are scaffolding proteins that are critical for maintaining synaptic integrity by clustering, organizing and functionally regulating synaptic proteins. Current anti-glaucoma therapies target IOP as the sole modifiable clinical parameters. Long-term pharmacotherapy and surgical treatment do not prevent gradual visual field loss as the disease progresses, highlighting the need for new complementary, alternative and comprehensive treatment approaches. Vesl/Homer expression was measured in the retinae of DBA/2J mice, a preclinical genetic glaucoma model with spontaneous mutations resulting in a phenotype reminiscent of chronic human pigmentary glaucoma. Vesl/Homer proteins were differentially expressed in the aged, glaucomatous DBA/2J retina, both at the transcriptional and translational level. Immunoreactivity for the long Vesl-1L/Homer 1c isoform, but not of the immediate early gene product Vesl-1S/Homer 1a was increased in the synaptic layers of the retina. This increased protein level of Vesl-1L/Homer 1c was correlated with phenotypes of increased disease severity and a decrease in visual performance. The increased expression of Vesl-1L/Homer 1c in the glaucomatous retina likely results in increased intracellular Ca2+ release through enhancement of synaptic coupling. The ensuing Ca2+ toxicity may thus activate neurodegenerative pathways and lead to the progressive loss of synaptic function in glaucoma. Our data suggest that higher levels of Vesl-1L/Homer 1c generate a more severe disease phenotype and may represent a viable target for therapy development.

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Section: Methodsmentioning

confidence: 99%

Differential up-regulation of Vesl-1/Homer 1 protein isoforms associated with decline in visual performance in a preclinical glaucoma model

et al. 2014

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“…The strength of the association was designated as no correlation for 0.0 # r # 0.2, weak correlation for 0.2 # r # 0.4, moderate correlation for 0.4 # r # 0.6, and strong correlation for 0.6 # r # 1.0. 22,23 …”

Section: Study Participants and Methodsmentioning

confidence: 99%

Normative Data Set Identifying Properties of the Macula Across Age Groups

Sabates¹,

Vincent²,

Koulen³

et al. 2011

Retina

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A database for normal macular thickness and sensitivity was generated with a combined microperimetry SD-OCT system as the basis for comparison of outcome parameters in patients with macular abnormality. Mean retinal sensitivity decreased significantly only in the age group of participants ≥ 70 years and in peripheral portions of the macula in individuals aged ≥60 years, with increasing distance from the fovea, while other parameters, their correlations and covariates, were not affected within the normative data set. No relationship was detected between retinal thickness and retinal sensitivity in the healthy macula.

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“…Regrettably, the distribution of the correlation coefficient (in our case FSC) is not normal and rather complicated, so the test is constructed using Fisher’s z -transformation (Bartlett, 1993):

z = \frac{1}{2} log \frac{1 + FSC}{1 - FSC} = arctanh (FSC) .

…”

Section: Fourier Shell Correlation and Its Relation To Spectral Signamentioning

confidence: 99%

Resolution Measures in Molecular Electron Microscopy

Penczek¹

2010

Methods in Enzymology

127

115

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Resolution measures in molecular electron microscopy provide means to evaluate quality of macromolecular structures computed from sets of their two-dimensional line projections. When the amount of detail in the computed density map is low there are no external standards by which the resolution of the result can be judged. Instead, resolution measures in molecular electron microscopy evaluate consistency of the results in reciprocal space and present it as a one-dimensional function of the modulus of spatial frequency. Here we provide description of standard resolution measures commonly used in electron microscopy. We point out that the organizing principle is the relationship between these measures and the Spectral Signal-to-Noise Ratio of the computed density map. Within this framework it becomes straightforward to describe the connection between the outcome of resolution evaluations and the quality of electron microscopy maps, in particular, the optimum filtration, in the Wiener sense, of the computed map. We also provide a discussion of practical difficulties of evaluation of resolution in electron microscopy, particularly in terms of its sensitivity to data processing operations used during structure determination process in single particle analysis and in electron tomography.

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Linear Modelling of Pearson's Product Moment Correlation Coefficient: An Application of Fisher's z-Transformation

Cited by 25 publications

References 7 publications

Differential up-regulation of Vesl-1/Homer 1 protein isoforms associated with decline in visual performance in a preclinical glaucoma model

Differential up-regulation of Vesl-1/Homer 1 protein isoforms associated with decline in visual performance in a preclinical glaucoma model

Normative Data Set Identifying Properties of the Macula Across Age Groups

Resolution Measures in Molecular Electron Microscopy

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