Noise analyses

For a weU-designed, weU-made HgCdTe photoconductoi detector (76,77), g-r noise is dominant and may be expressed in terms of a minority carrier densityp and majority carrier density n. Semiconductor noise analysis for the HgCdTe photoconductor yields,... 

Computers may be used for noise analysis when connected to dedicated hardware devices. One machine incorporates a narrow-band analyzer, octave and one-third octaves with all the features of an environmental noise analyzer. These devices cost much less than purchasing all the dedicated instmments separately. They may be obtained in portable form but are rarely weatherproofed for outdoor use. 

Benmouna, F. and Johannsmann, D. (2004). Viscoelasticity of gelatin surfaces probed by AFM noise analysis. Langmuir 20,188-193. 

Changes in the occupancy of the open-channel state of the receptor as a function of time (pA2R (t)) in response to a perturbation of the receptor equilibrium can be used to obtain information about the rates of channel gating and the interaction of dmgs with ion-channel receptors. The system is said to relax towards a new equilibrium. The time course of the relaxation is used to measure rates from the average behavior of many ion channels in a recording, while noise analysis uses the frequency of the moment-to-moment fluctuations in occupancy of the open-channel state at equilibrium to provide information about the rates in the receptor mechanism. 

The assumption that (> is very small has been used when studying the effects of channel blockers on synaptic currents, as the transmitter concentration (and hencepAlB) is probably small during the decay phase of the current. During noise analysis experiments, a low agonist concentration is used so that, again, under these conditions (5 should be small. 

W Van Driessche, D Erlij. (1983). Noise analysis of inward and outward Na+ currents across the apical border of ouabain-treated frog skin. Pfluegers Arch 398 179-188. 

Channels associated with capacitative calcium ion entry have been characterized electrophysiologically. In leukocytes, the current associated with the depletion of intracellular Ca2+ stores is highly Ca2+-selective and, on the basis of noise analysis, is believed to involve minute single channels [16] (see Ch. 6). This is the calcium release-activated calcium current (ICrac)- In other cell types, currents with significantly different properties have been identified, including in some instances store-operated nonse-lective cation channels. These marked electrophysiological distinctions may be indicative of distinct channel types mediating capacitative calcium ion entry in different cell types. 

Select the AC Sweep/Noise Analysis type and fill in the dialog box as shown below. 

I disagree with Dr. Thomas that there are no known biological channels or carriers. I know of at least one example of a clearly demonstrated channel. This is the acetylcholine activated channel in denervated muscle demonstrated so elegantly by Neher and Sackmann (Nature, 260, 119, 1976), who resolved unit conductance jumps that are far too large to be accounted for by a carrier mechanism. A less unambiguously demonstrated example of channels are the Na+ and K+ channels of nerve, which both by noise analysis and pharmacological evidence imply the movement of about 1000 times as many ions in a unit of time as is reasonable for any diffusive carrier mechanism across the entire membrane. 

Noise Analysis Transient Analysis Fourier Analysis Monte Carlo Analysis Temperature Analysis... 

To ensure that each pixel is correctly exposed, a minimum number of electrons must strike each pixel. Since electron emission is a random process, the actual number of electrons striking each pixel, n, will vary in a random manner about a mean value, n. Adapting the signal-to-noise analysis found in Schwartz (1959) to the case of binary exposure of a resist, one can show straightforwardly that the probability of error for large values of the mean number of electrons/pixel it is /[( /2) ] 2. This leads to the following table of probability of error of exposure ... 

Neher E, Sakaba T (2001) Combining deconvolution and noise analysis for the estimation of transmitter release rates at the calyx of held. J Neurosci 21 444-61 Nelson ED, Kavalali ET, MonteggiaLM (2006) MeCP2-dependent transcriptional repression regulates excitatory neurotransmission. CurrBiol 16 710-16 Nicholls DG (2003) Bioenergetics and transmitter release in the isolated nerve terminal. Neu-rochem Res 28 1433 11... 

Furthermore, for thermistor applications it is very important that noise analysis should be done, not only to have more useful information on the material itself but to quantify the certainly present l/f noise. 

Noise analysis obtained from microelectrochemical investigations of stainless steels under potentiostatic conditions revealed that the current noise, expressed as standard deviation a of the passive current, increases linearly with the size of the exposed area, whereas the pitting potential decreases.47 However, to complete the electrochemical studies and distinguish between repassivating superficial pits and penetrating ones, microscopic studies are highly desirable. The scanning reference electrode technique (SRET) should be an appropriate complementary tool.28... 

Flicker-noise spectroscopy — The spectral density of - flicker noise (also known as 1// noise, excess noise, semiconductor noise, low-frequency noise, contact noise, and pink noise) increases with frequency. Flicker noise spectroscopy (FNS) is a relatively new method based on the representation of a nonstationary chaotic signal as a sequence of irregularities (such as spikes, jumps, and discontinuities of derivatives of various orders) that conveys information about the time dynamics of the signal [i—iii]. This is accomplished by analysis of the power spectra and the moments of different orders of the signal. The FNS approach is based on the ideas of deterministic chaos and maybe used to identify any chaotic nonstationary signal. Thus, FNS has application to electrochemical systems (-> noise analysis). 

In some cases the noise can carry some useful information, see - noise analysis. 

As was expected from the signal-to-noise analysis, the effects of the several variables on the capacitive responses were much poorer structural predictors. Classification accuracies ranged between 60.0 and 75.6%. 

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