Sign sequence

Go through the variable matrix and look for the experiment in which the signs of the variable setting show the best correspondance to the sign sequence of the effects. This experiment is probably the aberrant one. 

Sign sequences for experimental designs with n runs for n = 8, 12, 16, 20, 24, 28 are given here. It is rare that more than 27 variables are involved in synthetic procedures. Readers who are interested in constructing larger designs, should consult the paper by Plackett and Burman. 

Special attention should be paid to one-sided deviation from the control limits, because systematic errors more often cause deviation in one direction than abnormally wide scatter. Two systematic errors of opposite sign would of course cause scatter, but it is unlikely that both would have entered at the same time. It is not necessary that the control chart be plotted in a time sequence. In any... 

The plus sign indicates a positive sequence harmonic and the minus. sign a negative sequence harmonic. Their effect is same as for the positive and the negative seqtience components discussed in Section I2.2(v) and ctiuses pulsation in the magnetic field and hence, in the torque of a rotiitimi machine. 

However, (-)-12 was shown to have (R)- Z) configuration by chemical correlation1033, and thus, in both metal-exchange steps, a/7//-SE2 -processes are involved. This, and the sign of optical rotation of intermediate stannanes, corresponds well with other published results111. Fortunately, this error has no implication for the stereochemical outcome of the overall sequence. 

In using Kaptein s rules in later sections, the sequence of signs will be that corresponding to the parameters as given in equations (39a) and (39b). 

Figure 48-2. Probable sequence of events in the causation of the major signs exhibited by patients with Marfan syndrome (MIM 154700).

It is important to pay careful attention to the signs, which we have done by carrying out the calculations in sequence. First, muitiply each standard enthalpy, including its sign, by the appropriate coefficient. 

For phase encoding of a velocity component, a gradient pulse sequence similar to the sequence in Figure 2.9.4(b) can be used. Two gradient pulses of duration t and of the same magnitude of the amplitude Gx but with opposite sign are applied. The position dependent term of the phase shift vanishes whereas the velocity dependent term provides a finite phase shift proportional to the velocity component [see Figure 2.9.4(b)] ... 

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