Tracing, graphic

DIRECT GRAPHICAL TRACING OF TRANSFORMATIONS OF FATTY OILS... 

In the method of Weber for the characterization of catalytical chemical reactions use is made of a very simple principle of graphical tracing, in which the most important actions of the catalyst, viz. the conversion of the starting material, the formation of the desired products and the formation of by-products are considered. 

Deluca G, Zecchini A. II tracciato elletroencefalografico nelkintossicazione da vitamina D. [The electroencephalo-graphic tracing in vitamin D intoxication.] Minerva Pediatr 1964 16 1276-9. 

The cardiac cycle is tightly controlled by the cardiac conducting system, which initiates electrical impulses and carries them, via a specialized conducting system, to the myocardium. The surface electrocardiogram (EGG) records changes in potential and is a graphic tracing of the variations in electrical potential caused by the excitation of the heart muscle and detected at the body surface. Clinically, the EGG is used to identify (1) anatomic, (2) metabolic, (3)... 

Photographic film, packaging films, graphic tracing films, display boxes, spectacle frames, hair brushes, combs. 

Classically the electrocardiogram (ECG) was believed to be a graphic tracing of the electric current produced by the myoneural activity associated with heart muscle excitation. The normal ECG, it was believed, showed deflections resulting from atrial and ventricular activity. The first signal, P, is due to atrial excitation with the QRS deflections arising from ventricular activity. T waves are believed to be due to ventricular recovery (repolarization) while the U waves are seen in the normal ECG and are accentuated in hypokalaemia (low potassium levels in the blood). 

As shown previously, vibrations can be displayed graphically as plots which are referred to as vibration profiles or signatures. These plots are based on measurable parameters (i.e., frequency and amplitude). Note that the terms profile and signature are sometimes used interchangeably by industry. In this chapter, however, profile is used to refer either to time-domain (also may be called time trace or waveform) or frequency-domain plots. The term signature refers to a frequency-domain plot. 

This evolution may then be represented graphically as follows (see figure 11.6). The axiom n(0) = 0 appears as a simple stem at time t = 0. At time t = 1, A(0) -> 2(1)3 so that the single stem value 0 is changed to a 2 , the stem itself is lengthened by on< unit with the value 3 attached at the top and a f)ranch attached on the left-hand side with value 1 . Figure 11.6 traces the evolution of this system for two more time steps. 

Field Stabilization Energies, or LFSE s. The variation in LFSE across the transition-metal series is shown graphically in Fig. 8-6. It is no accident, of course, that the plots intercept the abscissa for d, d and ions, for that is how the LFSE is defined. Ions with all other d configurations are more stable than the d, d or d ions, at least so far as this one aspect is concerned. For the high-spin cases, we note a characteristic double-hump trace and note that we expect particular stability conferred upon d and d octahedral ions. For the low-spin series, we observe a particularly stable arrangement for ions. More will be said about these systems in the next chapter. 

Figure 31.4 shows the biplot of the trace elements and wind directions for the case when a = p = 0.5. Since here we have that a + P equals 1, we can reconstruct the values in the columns of the data table X by means of perpendicular projections upon unipolar axes. In Fig. 31.4a we have drawn a unipolar axis through Cl. Perpendicular projection of the four wind directions upon this axis reconstructs the order of the concentrations of Cl at the four wind directions as listed in Table 31.1. Now we have established a way which leads back from the graphic display to the tabulated data. This interpretation of the biplot emphasizes the one-to-one relationship between the data and the plot. Such a relationship is also inherent in the ordinary bivariate (or Cartesian) diagram. 

Once an electron density map has become available, atoms may be fitted into the map by means of computer graphics to give an initial structural model of the protein. The quality of the electron density map and structural model may be improved through iterative structural refinement but will ultimately be limited by the resolution of the diffraction data. At low resolution, electron density maps have very few detailed features (Fig. 6), and tracing the protein chain can be rather difficult without some knowledge of the protein structure. At better than 3.0 A resolution, amino acid side chains can be recognized with the help of protein sequence information, while at better than 2.5 A resolution solvent molecules can be observed and added to the structural model with some confidence. As the resolution improves to better than 2.0 A resolution, fitting of individual atoms may be possible, and most of the... 

Because of this complexation capacity, any standard addition performed at high pH will not return 100% of the spike, so a true value for the copper concentration cannot be calculated. Therefore, after an initial measurement at high pH the sample was acidified to pH 1.0 with 0.5 ml acid and another trace obtained. This compared the amount of copper released at low pH with the labile fraction at high pH. Standard additions were performed on the sample at low pH so almost all of the spike was returned. This allowed an estimate to be made of the percentage of total copper that was labile at high pH, and the quantification of this fraction in pg/1. This is illustrated graphically in Fig. 5.9. 

A sample may be characterized by the determination of a number of different analytes. For example, a hydrocarbon mixture can be analysed by use of a series of UV absorption peaks. Alternatively, in a sediment sample a range of trace metals may be determined. Collectively, these data represent patterns characteristic of the samples, and similar samples will have similar patterns. Results may be compared by vectorial presentation of the variables, when the variables for similar samples will form clusters. Hence the term cluster analysis. Where only two variables are studied, clusters are readily recognized in a two-dimensional graphical presentation. For more complex systems with more variables, i.e. //, the clusters will be in -dimensional space. Principal component analysis (PCA) explores the interdependence of pairs of variables in order to reduce the number to certain principal components. A practical example could be drawn from the sediment analysis mentioned above. Trace metals are often attached to sediment particles by sorption on to the hydrous oxides of Al, Fe and Mn that are present. The Al content could be a principal component to which the other metal contents are related. Factor analysis is a more sophisticated form of principal component analysis. 

As seen in equations (32)-(34), the forward adsorptive flux depends upon the concentration of free cell surface carriers. Unfortunately, there is only limited information in the literature on determinations of carrier concentrations for the uptake of trace metals. In principle, graphical and numerical methods can be used to determine carrier numbers and the equilibrium constant, As, corresponding to the formation of M — Rcen following measurement of [M] and (M —Rceii. For example, a (Scatchard) plot of (M — RCeii /[M] versus (M — RCeii should yield a straight line with a slope equal to the reciprocal of the dissociation constant and abscissa-intercept equal to the total carrier numbers (e.g. [186]). 

Fig. 6 Typical PET probes (a) and representative fluorescence light-up responses toward selected metal ions in tabulated (b) and graphical form (c trace 1 = 14, trace 2 = 14-(Zn2+)2, trace DMA = 9,10-dimethylanthracene in MeCN). Color code coordinating atoms in blue, atoms which take part in the complexation and show (main, in 14) PET activity in orange, fluorophore in green. Lincoln and co-workers have demonstrated that the attachment of two dimethylamino groups through propylene spacers to the 9,10-positions of anthracene has a more than 100-fold weaker PET activity than the attachment through methylene spacers [62]. The blue N atoms in 14 are thus predominantly responsible for coordination. For symbols, see Fig. 3. Quantum yield of 14 in MeCN estimated from intensity readings published in [61] and quantum yield data of the parent compound without active PET, DMA, published in [63]. (Reprinted in part with permission from [61]. Copyright 1988 American Chemical Society)...

Seawater studies require certified reference materials for biologically important dissolved components such as carbon (both inorganic and organic), nutrients, and trace metals, as well as for salinity, which is hydro-graphically important. A number of the committee s key recommendations therefore explicitly address these parameters. There is also a striking need for reference materials based on particulate matrices, where many of the analytical techniques used are matrix dependent and differ markedly... 

The TRAACS 800+ is controlled by a personal computer and the features provided include complete interactive control via keyboard or mouse calculation of results as necessary taking into account baseline or sensitivity drift, graphical output of calibration curves for all calibration types—either Hnear or non-hnear, input facility for sample identification data allowing storage on disc and real-time results together with chart traces on a computer printer. The programs allow easy access to input or data files and connection to other computers, and gives system performance verification to CLP standards and built-in QC charts. 

The graphical representation of the average chemical composition for the trace elements of the BIF in this study are... 

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