crest

(noun)

The ridge or top of a wave.

Related Terms

Examples of crest in the following topics:

  • Development of the Peripheral Nervous System

    • The peripheral nervous system develops from two strips of tissue called the neural crest, running lengthwise above the neural tube.
    • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation .
    • After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm.
    • The emergence of the neural crest was important in vertebrate evolution because many of its structural derivatives are defining features of the vertebrate clade.
    • The neural tube will give rise to the central nervous system, while the neural crest will give rise to the peripheral nervous system.

  • Development of the Integumentary System

    • The integumentary system develops from all embryonic layers (ectoderm, mesoderm and neural crest cells).
    • Fetal skin forms from three layers: ectoderm, mesoderm, and neural crest cells.
    • Melanoblasts that will form melanocytes migrate with neural crests cells to the epithelium and begin producing melanin prior to birth.

  • Conditions for Wave Interference: Reflection due to Phase Change

    • If a crest of one wave meets a crest of another wave of the same frequency at the same point, then the magnitude of the displacement is the sum of the individual magnitudes.
    • Destructive interference occurs when the crest of one wave meets a trough of another wave.
    • When light is reflected off a medium with a higher index of refraction, crests get reflected as troughs and troughs get reflected as crests.

  • Wavelength, Freqency in Relation to Speed

    • The amplitude is half of the distance measured from crest to trough.
    • We also observe the wavelength, which is the spatial period of the wave (e.g. from crest to crest or trough to trough).
    • The frequency of a wave is the number of cycles per unit time -- one can think of it as the number of crests which pass a fixed point per unit time .
    • For such a component, any given phase of the wave (for example, the crest) will appear to travel at the phase velocity.

  • Transverse Waves

    • The wavelength spans crest to crest while the amplitude is 1/2 the total distance from crest to trough.
    • The wavelength is the distance between adjacent crests.
    • The amplitude is the 1/2 the distance from crest to trough.

  • Introduction to Light Energy

    • Scientists can determine the amount of energy of a wave by measuring its wavelength, the distance between consecutive points of a wave, such as from crest to crest or from trough to trough .
    • The wavelength of a single wave is the distance between two consecutive points of similar position (two crests or two troughs) along the wave.

  • Doppler Effect

    • The time between the arrival for two crests of the wave in the unprimed frame is given by,

  • Young's Double Slit Experiment

    • Constructive wave interference occurs when waves interfere with each other crest-to-crest (peak-to-peak) or trough-to-trough (valley-to-valley) and the waves are exactly in phase with each other.
    • Destructive wave interference occurs when waves interfere with each other crest-to-trough (peak-to-valley) and are exactly out of phase with each other.
    • The waves all start out in phase (matching crest-to-crest), but depending on the distance of the point on the wall from the slit, they could be in phase at that point and interfere constructively, or they could end up out of phase and interfere with each other destructively.

  • Bone Grafting

    • Bone grafts may be autologous (bone harvested from the patient's own body, often from the iliac crest), allograft (cadaveric bone usually obtained from a bone bank), or synthetic (often made of hydroxyapatite or other naturally-occurring and biocompatible substances) with similar mechanical properties to bone.
    • In this case, bone can be taken from the chin, or from the pilot holes for the implants, or even from the iliac crest of the pelvis and inserted into the mouth underneath the new implant.

  • Ilium

    • It has an external and internal surface, a crest (illiac crest), and an anterior and posterior border.