List of symbols
| Symbol | Description |
| x, y, z, | Spatial coordinates (x, horizontal, axial; y, transverse; z, vertical) |
| r, ϕ | Polar spatial coordinates (radial and angle) |
| F, F0, F/F0, ΔF/F0 | Fluorescence, initial, normalized, increase |
| a, FWHM, T | Spark amplitude, FWHM, rise time |
| g(a), l(a), u(a) | Probability density of the distributions of amplitude (in focus, 3-D, 2-D) |
| G(a), L(a), U(a) | Histograms, sampling of the distributions g(a), l(a), u(a) |
| h(z,σ) | Gaussian function of vertical coordinate z with standard error σ |
| ζ | Vertical separation of spark source and focal plane |
| δ | Normalized difference in fluorescence (defined by Eq. 1) |
| C3 | “Three-point criterion” (limit value of δ for sparks in focus) |
| D | Half depth of slice in focus, µm |
| ρ | Pearson’s linear correlation coefficient |
| [Ca2+], [Ca2+]cyto, [Ca2+]SR | Free Ca2+ concentration, in cytosol, in SR |
| N, Po, i | Number of channels, channel open probability, unitary current |
| Symbol | Description |
| x, y, z, | Spatial coordinates (x, horizontal, axial; y, transverse; z, vertical) |
| r, ϕ | Polar spatial coordinates (radial and angle) |
| F, F0, F/F0, ΔF/F0 | Fluorescence, initial, normalized, increase |
| a, FWHM, T | Spark amplitude, FWHM, rise time |
| g(a), l(a), u(a) | Probability density of the distributions of amplitude (in focus, 3-D, 2-D) |
| G(a), L(a), U(a) | Histograms, sampling of the distributions g(a), l(a), u(a) |
| h(z,σ) | Gaussian function of vertical coordinate z with standard error σ |
| ζ | Vertical separation of spark source and focal plane |
| δ | Normalized difference in fluorescence (defined by Eq. 1) |
| C3 | “Three-point criterion” (limit value of δ for sparks in focus) |
| D | Half depth of slice in focus, µm |
| ρ | Pearson’s linear correlation coefficient |
| [Ca2+], [Ca2+]cyto, [Ca2+]SR | Free Ca2+ concentration, in cytosol, in SR |
| N, Po, i | Number of channels, channel open probability, unitary current |