Results for: Threshold

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In Science

What is threshold energy?

Threshold Energy Threshold energy is the energy level where some chemical/physical action happens. For instance water boils at 100 deg C the water molecule attain… (MORE)

Sadlek24

18 Contributions

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In Human Anatomy and Physiology

What is renal threshold?

Answer Renal threshold is what happens when there is an overabundance of glucose in the body, the blood glucose levels will then get above 170mg/100ml (normal is 70mg/1… (MORE)

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In Auto Parts and Repairs

What is absolute threshold?

Absolute threshold is the smallest level of energy required by an external stimulus to be detectable by the human senses, including vision, hearing, taste, smell and touch… (MORE)

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In Computer Networking

What is the fragmentation threshold?

The maximum frame size wireless device can transmit without fragmenting the frame. A collision happens when two devices that use the same medium transmit packets … (MORE)

Badgerroy123

6 Contributions

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In Cars & Vehicles

What is threshold breaking?

its how racing drivers break. rather than pump the breaks to stop the car skidding you keep the breaks on all the time but lift off gently as soon as the car starts to skid bu… (MORE)

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In Taxes and Tax Preparation

What is income threshold?

An income threshold is the amount of earnings a person can receive before they have to start paying taxes. Each state has different amounts to this threshold.

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In Differentials

What is differential threshold?

The differential threshold of retinal sensitivity, as contrasted with the absolute threshold, has also been investigated in amblyopic eyes. In testing the differential thresho…ld, one asks how much brighter than its surroundings a test field must be so that it may be just perceived. A number of workers studied this question, and most found a slight elevation of the differential threshold of amblyopic eyes, provided the test field was small enough, on the order of magnitude of a few minutes. In other words, a small, shallow relative scotoma of the amblyopic eyes could be shown to exist. Various methods have been used to establish this fact, among them monocular static perimetry. Aulhorn19reported on 70 amblyopes tested with this method, 35 of whom had foveolar or extrafoveolar depression, 26 had only flattening of the curve, and 9 had the normal foveolar peak in their sensitivity curve. Donahue and coworkers120 recently revisited this problem, using automated perimetry. They found that all types of amblyopia are associated with a generalized depression of light sensitivity, which was proportionately greatest at the fovea and highly correlated with visual acuity loss. A higher-than-normal central differential threshold was also found by EF Miller309 under photopic conditions using rectangular test objects in the shape of luminous bars or slits of different widths. Grosvenor174 confirmed the work of Miller but added important amplifications by testing normal and amblyopic eyes over a wide range of exposure times and background luminance levels. He found that "the normal and amblyopic eyes have essentially equal thresholds at the absolute threshold level, which substantiates the work of Wald and Burian." In addition, the fact that the thresholds for the two eyes are not the same at higher luminance levels "bears out their prediction that amblyopia has its effects mainly at higher levels of luminance."174 Because of the impaired differential threshold of the light-adapted amblyopic eyes, Harms184 questioned the conclusion by Wald and Burian457 that the entire apparatus of simple light perception was normal in amblyopic eyes. However, Wald456 pointed out that every brightness discrimination involved some degree of form discrimination, which indeed is impaired in amblyopia. Jung234 explained the apparent contradiction between the findings of Wald and Burian and those of Harms by the following neurophysiologic considerations. The lateral inhibition, essential to contrast vision and visual acuity, disappears in dark adaptation, and spatial summation prevails. For scotopic vision there is no reduction in darklight perception, and diffuse light perception is retained by the amblyopic eye. This favors a separate neuronal mechanism for brightness perception. Herzau and coworkers201 measured the differential light thresholds in the nasal and temporal visual field periphery in patients with strabismic amblyopia and found consistent threshold elevation in the nasal field. These data may be the psychophysical correlate of our finding that in human strabismic amblyopia the LGN has the most pronounced cell shrinkage in layers connected with the temporal retina, which corresponds to the nasal visual field.348 Bowering and coworkers53 evaluated the visual field with manual Goldmann perimetry in patients with deprivation amblyopia from congenital cataracts. They found in all children a restricted field, especially temporally, even when the deprivation began as late as 6 years of age and lasted less than 6 months. The restrictions were larger than those shown by the adults who developed cataracts. The restrictions were also larger after longer deprivation and monocular deprivation than after binocular deprivation. However, children who regularly patched the fellow nondeprived eye and, therefore, experienced less interocular competition, exhibited smaller restrictions temporally. Neither visual acuity nor optical factors could account for all of the restrictions in the deprived children. (MORE)

Ey123

2 Contributions

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In Neurophysiology

What is stimulus threshold?

ST - In regards to excitable cell (i.e. neurons) the minimum mV need to trigger a AP (action potential) and is around -40mV (although this may vary depending on the cell). I… (MORE)

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In Science

What is threshold wavelength?

The greatest wavelength of radiation for a specified surface for the emission of electrons.

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In Uncategorized

Why is a threshold called a threshold?

It was aptly named a threshold as it holds the thresh inside the structure to mitigate the dust from the dirt floors commonly used during this time period.