Fields and the Body

As the English satirist Samuel Butler once said A right way of looking at things will see through almost anything.  

Fortunately, there are now better ways to assess the inner state of our bodies cameras that make x-ray seem almost like a relic of the days of saddlebag doctors. These new devices rely on the dramatic advances in solid-state electronics and computer technology and on vastly improved knowledge of sound waves, infrared sources, the protons in the nuclei of hydrogen atoms, radio waves, magnetism, and in many applications, superconductivity. 

There is CT, for computerized tomography, a wedding of x-ray and the computer that scans a portion of, say, the brain by revolving an x-ray tube around the head, converting the pictures into a digital computer code to make high-resolution, three-dimensional video images accurate to. 9 millimeter. Differences in tissue density, between abnormal and normal tissue, are revealed fine details of bone structure appear clearly the location of tumors is pinpointed. 

PET (positron emission tomography) uses trace amounts of radioisotopes to measure blood flow through tissue and to determine if a patient s biochemical processes are functioning properly. 

The spectrometer is also used to identify a patient s so-called anaerobic threshold, the point at which the oxygen supply to cells can no longer keep up with demands. A runner, for example, has a certain speed at which he or she can maintain a steady pace for long periods. Any significant pickup in momentum will usually lead to rapid fatigue 

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Page 173. In the last analysis. . Personal interview. CHAPTER 13 MAGNETIC FIELDS AND THE BODY... 

Whenever a body is subject to an electric field and the body is non-spherical, there exists the possibility of creating a torque. See Figure 4A. Even for spherical bodies, if the polarization is a tensor not parallel to the field there exists the possibility for a torque to arise. For example, early experiments by Griffin and StowelF showed that Euglena (nonspherical) would align parallel to the applied field at low frequencies, or at very high... 

A superposition of this scattered field and the incident field would satisfy the boundary conditions. An approximation to the scattered field can be generated by a distribution of body forces Qz acting in the z-direction in the half-plane x = 0, z < 0, i.e. where the crack would be. Because of symmetry this distribution of body forces gives u = 0 at x = 0, and also rz(z) = Qz(z)/2 just to the left of the plane of the crack. Hence for x < 0 the scattered field is found by selecting... 

Fig. 11.1. Center-of-mass or Jacobi coordinates R and r used to describe the fragmentation of a triatomic molecule ABC into A and BC. S and s are the centers-of-mass of ABC and BC, respectively, v is the relative velocity of the recoiling fragments in the center-of-mass system. The space-fixed z-axis is parallel to the vector Eo of the electric field, while the body-fixed z -axis is parallel to the scattering vector R at all times. The azimuthal angle ip, which is not indicated in the figure, describes rotation in the plane perpendicular to R.

Are the effects discussed in this section electrochemical They arise because of fluctuating electromagnetic and in some of them, purely magnetic, fields in the body tissue. However, what they induce in the tissues are electric currents, ionic movements, and those and their resulting effects involve electrochemical mechanisms. 

The first unipolar transistor was a JFET the layout of an n-channel JFET is given in Fig. 9.31. The mechanism of function is similar to the MOSFET The n-channel is narrowed by the electric field applied to the gate and the body. The operational characteristics, mutatis mutandis, resemble those of the MOSFET discussed above. 

Belief that magnetic fields penetrate the body and heal damaged tissues... 

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