Intensity data, normalization

PSI allows the constant monitoring of all charged species at a time resolution equal to the scan rate, and the abundances of the various species of interest can be plotted against time. Reaction times are those the reactants spend in the flask plus the time they spend in the tube. The additional reaction time can be calculated (vide supra) but fast reactions may be somewhat difficult to follow. Here, making the tube as short as possible is beneficial. In the case of the hydrolysis reaction, we see the protonated starting material, [Fmoc-Arg(Pbf)-OH + H]+ at m/z 649, disappear to be replaced by protonated forms of both fragments, [Fmoc-Arg-OH + H]+ at m/z 397 and [Pbf+H]+ at m/z 191. We present the traces in 2 forms (a) raw intensity data and (b) normalized to the total intensity of all ions of interest (i.e. those at m/z 649, 397 and 191). 

The samples were excited at 549 nm and the resultant fluorescence emission spectra were digitized. The emission spectra of i-2 differed only in relative intensity. A direct comparison between the integrated and normalized fluorescence spectra of i-2 was made with that of ZnTPP. The data normalized to the known fluorescence quantum yield of ZnTPP(ii) are listed in Table II. Fluorescence lifetimes were determined on 10 M solutions of... 

Figure 7.15 Fringe structure of the anti-Stokes scattering observed by the interference of two Raman excitations. Open circles are observed data and solid lines are sine functions fitted to the observed data, (a) The delay is scanned around 10 ps. (b) The delay Tjj g is scanned around 500 ps. In both cases, the probe pulse is irradiated at 1 ns after the first excitation. The intensity is normalized by the signal intensity when only the single IRE pulse is irradiated. Reproduced with permission from Ref. [43]. Copyright 2013 by the American Physical Society.

One common microarray data normalization method is to calculate a normalization factor on a per array basis or across an entire experiment. The primary assumption for using a singular normalization factor is that the volume of labeled sample is comparable across the two channels. Thus, due to the large population of labeled cDNA within the uniform volume it is assumed that the same number of labeled cDNAs exist in both samples. Ideally, the overall intensity in the two channels will be the same. Furthermore, any increases in labeled cDNAs, due to increases in mRNA, must result in decreases of some other labeled cDNAs. Typical methods include mean- or median-centering, where the mean/median values are centered within the data distribution, and z-score normalization which adds a scaling factor to mean-centering. 

Figure 15.3 Chemiluminescence intensity decay measured on both SiFs and glass as a hinction of time (Top) and the data normalized (Top-insert). Normalized chemiluminescence intensity on both SiFs and a continuous silver film (Bottom). Photograph of the emission from both the continuous silver film and the...

Similar quenching was also observed when the colloid was excited by a two-photon absorption process. The decrease in the fluorescent peak intensity as a function of the colloid filling factor is shown in figure 18.6, for one and two-photon excitation. The fluorescence intensity was normalized to the case of no NPs in the solution. Each solid line in figure 18.6 is a two exponential decay fitting. Same decay parameters were used to fit the experimental data, indicating that the NP-Tryptophan interaction is similar for one and two-photon excitation. 

For each Bragg reflection, the raw data normally consist of the Miller indices (h,k,l), the integrated intensity I(hkl), and its standard deviation [ a[I) ]. In Equation 7.2 (earlier), the relationship between the measured intensity / [hkl] and the required structure factor amplitude F[hkl) is shown. This conversion of I hkl) to F hkl) involves the application of corrections for X-ray background intensity, Lorentz and polarization factors, absorption effects, and radiation damage. This process is known as data reduction.The corrections for photographic and diffractometer data are slightly different, but the principles behind the application of these corrections are the same for both. 

FIG. 1. Total x-ray scattering intensity (powder sample plus capillary) of pure Ceo at 300 and II K. Light and heavy curves are data and model fits, respectively. Intensities are normalized to counts/sec at a synchrotron ring current of 100 mA the data were typically collected for S sec/point at a current of 150 mA. Top panel shows the entire profile on a semilogarithmic scale, and bottom panel shows a blowup of the same data in the region 2.5 < < 4.5 A on a linear scale. All profiles have been offset for clarity. 

In certain applications, e.g. when the normalized structure factors should be calculated (see section 2.14.2), the knowledge of the approximate scale factor is required before the model of the crystal structure is known. This can be done using various statistical approaches [e.g. see A.J.C Wilson, Determination of absolute from relative x-ray intensity data,... 

A number of authors have observed lower root mean square time averaged turbulent intensities, v, normal to the fiow direction for both high-polymer and surfactant DR systems compared with Newtonian solvents. There is a subtle difference between high-polymer and surfactant solution data. The former peak is at values >100 while the latter is at <100. Newtonian solvents peak at about y 100. " This, along with their different MDRAs and different limiting velocity profile slopes, suggests that their DR mechanisms may differ. 

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