P-waves

The basics of the method are simple. Reflections occur at all layers in the subsurface where an appreciable change in acoustic impedance is seen by the propagating wave. This acoustic impedance is the product of the sonic velocity and density of the formation. There are actually different wave types that propagate in solid rock, but the first arrival (i.e. fastest ray path) is normally the compressional or P wave. The two attributes that are measured are... 

In the future, it is expected to be possible to make more routine use of additional wave types, specifically shear or S waves (polarised to horizontal and vertical components) which have a transverse mode of propagation, and are sensitive to a different set of rock properties than P waves. The potential then exists for increasing the number of independent attributes measured in reflection surveys and increasing the resolution of the subsurface image. 

The combined S-, P-wave (l = 0, 1) contributions to the differential and integral cross sections are... 

For pure S-wave scattering, the difFerential cross section (DCS) is isotropic. For pure P-wave scattering, tlie DCS is symmetric about 0 = n/2, where it vanishes the DCS rises to equal maxima at 0 = 0, ti. For combined S- and P-wave scattering, the DCS is asynnnetric with forward-backward asynnnetry. 

Figure 3.12. Experimental configuration and velocity profiles demonstrating the use of VISAR interferometric techniques in pressure-shear instrumentation to determine in-plane shear motion as well as longitudinal (P-wave) motion (Chhabildas and Swegle, 1980).

Mild (5.S-6.5 mEq/L) to moderate (6.5-8 mEq/L) potassium blood level increases may be asymptomatic and manifested only by increased serum potassium concentrations and characteristic BOS changes such asdisappearance of P waves or Rereading (widening) of the QRS complex. 

Psueudopotentials should satisfy several basic requirements. For example, the pseudo and real

wave functions must be identical outside the core radius (>rc), not only in their spatial dependence but also in their absolute magnitudes such that two wave functions generate identical charge densities. The equality of the two types of wave functions outside the core radius in this context is guaranteed by imposing the following constraint ... 

A similar conclusion caimot be reached concerning the p waves (/ = 1). In fact the coupling term between the s and p waves (the Uumterm of the eq.(22)) is not small here and correspondingly the p wave of the molecular system cannot be expected to... 

Fig.2 p-wave phaseshifts. Full line GTO results, broken line STOCOS results, circles GTO basis states, points STOCOS basis states. 

Because the symptoms of all tachyarrhythmias are dependent on heart rate and are therefore essentially the same, diagnosis depends on the presence of PSVT on the ECG, characterized by narrow QRS complexes (usually less than 0.12 seconds). P waves may or may not be visible, depending on the heart rate. 

EKGs taken on two workers about 2.5 hours after an acute exposure to hydrogen sulfide showed cardiac arrhythmias (Krekel 1964). The workers were exposed for <5 minutes after a spill of sodium sulfide that broke down to release hydrogen sulfide. In one individual, a negative P wave indicating a substitute rhythm was noted, while in the other individual a continuous arrhythmia due to atrial flutter was found. EKGs for both men had returned to normal within 24 hours. 

Figure 13.4 Electrocardiogram. The electrocardiogram (ECG) is a measure of the overall electrical activity of the heart. The P wave is caused by atrial depolarization, the QRS complex is caused by ventricular depolarization, and the T wave is caused by ventricular repolarization.

The ECG has several noteworthy characteristics. First, the firing of the SA node, which initiates the heart beat, precedes atrial depolarization and therefore should be apparent immediately prior to the P wave. However, due to its small size, it does not generate enough electrical activity to spread to the surface of the body and be detected by the electrodes. Therefore, there is no recording of the depolarization of the SA node. 

Second, the area under the curve of the P wave is small compared to that of the QRS complex. This is related to the muscle mass of the chambers. The ventricles have significantly more muscle than the atria and therefore generate more electrical activity. Furthermore, although it may not appear to be the case given the spike-like nature of the QRS complex, areas under the QRS complex and the T wave are approximately the same. This is because these recordings represent electrical activity of the ventricles even though one is caused by depolarization and the other by repolarization. Either way, the muscle mass involved is the same. 

Using the ECG, the heart rate may be determined by calculating the time from the beginning of one P wave to the beginning of the next P wave, or from peak to peak of the QRS complexes. A normal resting heart rate in adults is approximately 70 beats/min. A heart rate of less than 60 beats/min is referred to as bradycardia and a heart rate of more than 100 beats/min is referred to as tachycardia. 

ECG TP segment P wave PR segment QRS complex ST segment T wave... 

The earliest ECG change (serum potassium 5.5 to 6 mEq/L) is peaked T waves. The sequence of changes with further increases is widening of the PR interval, loss of the P wave, widening of the QRS complex, and merging of the QRS complex with the T wave resulting in a sine-wave pattern. 

As a characteristic feature, both the gap functions have nodes at poles (9 = 0,7r) and take the maximal values at the vicinity of equator (9 = 7t/2), keeping the relation, A > A+. This feature is very similar to 3P pairing in liquid 3He or nuclear matter [17, 18] actually we can see our pairing function Eq. (39) to exhibit an effective P wave nature by a genuine relativistic effect by the Dirac spinors. Accordingly the quasi-particle distribution is diffused (see Fig. 3)... 

Independently of each other, Pauling and Slater worked out a quantum mechanical explanation of the directional valences characteristic of chemical molecules. They did this by proposing directional properties for the p wave functions and for the sp3 wave functions resulting from "hybridization" of electron wave functions, or orbitals.73... 

Recent experiments by Akamatsu et al. (1993) show that pressure has a significant elfect on Fe-Mg intracrystalline distribution (dK /dP = 2 Mbar ). At the upper pressure limit of stability of olivine (P 0.12 Mbar, corresponding to a depth of about 400 km p-wave seismic discontinuity, cf section 5.2.3), the increase in with respect to the P = 1 bar condition, Tand composition being equal, is about 0.24. For a Fogo olivine, this variation is similar to that induced by a T increase of about 250 °C (cf figure 5.11). 

MAS = H-MAS NMR spectroscopy at 298 K, ADLF = nuclear quadrupole resonance by level crossing (at 77 K), QE = quadrupole echo (static) NMR spectroscopy at low temperature of die solid state, p.wave = microwave spectroscopy of the gaseous state. 

Parenteral.Hyperkalemia Adverse reactions involve the possibility of potassium intoxication. Signs and symptoms include paresthesias of extremities flaccid paralysis muscle or respiratory paralysis areflexia weakness listlessness mental confusion weakness and heaviness of legs hypotension cardiac arrhythmias heart block ECG abnormalities such as disappearance of P waves, spreading and slurring of the QRS complex with development of a biphasic curve and cardiac arrest. 

Atrial fibrillation (AF) is one of the most common rhythm disturbances, and is characterized by the absence of discrete P wave and an irregular ventricular rhythm. Fibrillatory waves are either fine or... 

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