1.3 Describe the main reservoirs of infectious agents. 1.4 Describe the chain of transmission of communicable diseases and explain how infectious agents are transmitted by direct and indirect modes. 1.5 Describe the characteristics of susceptible hosts and the main risk factors for development of communicable diseases.
Seismic tomography. Seismic tomography is a technique for imaging the subsurface of the Earth with seismic waves produced by earthquakes or explosions. P-, S-, and surface waves can be used for tomographic models of different resolutions based on seismic wavelength, wave source distance, and the seismograph array coverage. The data received at seismometers are used to solve an inverse problem, wherein the locations of reflection and refraction of the wave paths are determined. This solution can be used to create 3D
Mechanical longitudinal waves are also called compressional waves or compression waves, because they produce compression and rarefaction when traveling through a medium. The other main type of wave is the transverse wave, in which the displacements of the medium are at right angles to the direction of propagation.ongitudinal waves include sound waves (vibrations in pressure, particle of displacement, and particle velocity propagated in an elastic medium) and seismic P-waves (created by earthquakes and explosions). In longitudinal waves, the displacement of the medium is parallel to the propagation of the wave.