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  2. Resting state fMRI - Wikipedia

    en.wikipedia.org/wiki/Resting_state_fMRI

    Resting state fMRI (rs-fMRI or R-fMRI), also referred to as task-independent fMRI or task-free fMRI, is a method of functional magnetic resonance imaging (fMRI) that is used in brain mapping to evaluate regional interactions that occur in a resting or task-negative state, when an explicit task is not being performed.

  3. Functional magnetic resonance imaging - Wikipedia

    en.wikipedia.org/wiki/Functional_magnetic...

    Heat causes electrons to move around and distort the current in the fMRI detector, producing thermal noise. Thermal noise rises with the temperature. It also depends on the range of frequencies detected by the receiver coil and its electrical resistance. It affects all voxels similarly, independent of anatomy. [56]

  4. Physics of magnetic resonance imaging - Wikipedia

    en.wikipedia.org/wiki/Physics_of_magnetic...

    Modern 3 Tesla clinical MRI scanner.. Magnetic resonance imaging (MRI) is a medical imaging technique mostly used in radiology and nuclear medicine in order to investigate the anatomy and physiology of the body, and to detect pathologies including tumors, inflammation, neurological conditions such as stroke, disorders of muscles and joints, and abnormalities in the heart and blood vessels ...

  5. Cosmic noise - Wikipedia

    en.wikipedia.org/wiki/Cosmic_noise

    Cosmic noise, also known as galactic radio noise, is a physical phenomenon derived from outside of the Earth's atmosphere. It is not actually sound, and it can be detected through a radio receiver , which is an electronic device that receives radio waves and converts the information given by them to an audible form.

  6. Diffusion-weighted magnetic resonance imaging - Wikipedia

    en.wikipedia.org/wiki/Diffusion-weighted...

    However, this proves to be very susceptible to measurement noise, so increasingly complex measures were developed to capture the measure while minimizing the noise. An important element of these calculations is the sum of squares of the diffusivity differences = (λ 1 − λ 2) 2 + (λ 1 − λ 3) 2 + (λ 2 − λ 3) 2. We use the square root ...

  7. NASA offers explanation for bizarre 'trumpet noise' phenomena

    www.aol.com/news/2015-05-22-nasa-attempts-to...

    Videos of eerie noises erupting from the skies have recently surfaced on YouTube, sending people into a panic around the world. The video above shows a particularly frightening episode of this ...

  8. Noise floor - Wikipedia

    en.wikipedia.org/wiki/Noise_floor

    Measurement from a spectrum analyzer showing a noise-like measurement from an unspecified component.. In signal theory, the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored.

  9. Noise (spectral phenomenon) - Wikipedia

    en.wikipedia.org/wiki/Noise_(spectral_phenomenon)

    Noise figure, the ratio of the output noise power to attributable thermal noise; Ambient noise level, the background sound pressure level at a given location; Noise power, with several related meanings; Noise spectral density, N o measured in Watt/Hertz; Noise temperature, temperature that would produce equivalent semiconductor noise