True duration

From the above discussion, it is apparent that the exponential asymptotic behaviour of KmU) characterizes the correlation between collisions rather than collision itself. Hence the quantity tm defined in Eq. (1.67) cannot be considered as a collision time. To determine the true duration of collision let us transform Eq. (1.63) to the integral-differential equation as was done in [51] ... 

The former approach, even though an approximation, has been deemed desirable by EFFAS in the face of the enormity of the task of calculating duration based on the individual cash flows of the constituent bonds. In the trivial case where all the bonds have exactly same yield, the average duration is the same as the true duration of the portfolio or the index. That is. 

We saw in the last chapter that the stationary-state approximation is apphc-able to free-radical homopolymerizations, and the same is true of copolymerizations. Of course, it takes a brief time for the stationary-state radical concentration to be reached, but this period is insignificant compared to the total duration of a polymerization reaction. If the total concentration of radicals is constant, this means that the rate of crossover between the different types of terminal units is also equal, or that R... 

The in equation 4.19 relates to the fact that this is not the true standard deviation, but an estimate to measure the process shift (or drift) in the distribution over the expected duration of production. Equation 4.20 is the best estimate for the standard deviation of the distribution as determined by CA with no process shift. 

The potential of LA-based techniques for depth profiling of coated and multilayer samples have been exemplified in recent publications. The depth profiling of the zinc-coated steels by LIBS has been demonstrated [4.242]. An XeCl excimer laser with 28 ns pulse duration and variable pulse energy was used for ablation. The emission of the laser plume was monitored by use of a Czerny-Turner grating spectrometer with a CCD two-dimensional detector. The dependence of the intensities of the Zn and Fe lines on the number of laser shots applied to the same spot was measured and the depth profile of Zn coating was constructed by using the estimated ablation rate per laser shot. To obtain the true Zn-Fe profile the measured intensities of both analytes were normalized to the sum of the line intensities. The LIBS profile thus obtained correlated very well with the GD-OES profile of the same sample. Both profiles are shown in Fig. 4.40. The ablation rate of approximately 8 nm shot ... 

It resembles atropine in its range of activity but in particular types of action it may differ quantitatively thus its action on the pupil is equal to that of atropine but shorter in duration, and that is also true of its antagonisni to the effect of acetylcholine on the isolated perfused cat s COTt, but its activity on the salivary gland and the blood pressure of the. IS greater than that of atropine, while its action on smooth muscle... 

Electrical supply systems and equipment are grounded in order to maintain the voltage at any part of the system at a known potential relative to true earth and to provide a path for current flow under earth fault conditions so that protective devices operate correctly. The connection to earth should be such that the flow of fault current to earth does not cause voltages or voltage gradients to be of sufficient magnitude or duration likely to cause danger. 

In terms of the duration of meetings, a duration of between 60 and 90 minutes is recommended. However, there can sometimes be exceptions where mentoring might take several hours - this is particularly true when the mentor is in coaching mode. ... 

High dropout rates notwithstanding, those who stay in treatment have excellent results. Clients remaining for 90 days or more do better than dropouts on legitimate employment, number of arrests, self-reported drug use, and antisocial behavior these results hold true at 1- and 5-year follow-ups (Bale et al. 1984 DeLeon 1985). However, some research showed a negative correlation between duration of residence and outcome, particularly for clients with extensive psychiatric symptoms, who do comparatively poorly in therapeutic community settings (McLeUan 1986). 

Under low-frequency excitation, the flame front is wrinkled by velocity modulations (Fig. 5.2.5). The number of undulations is directly linked to frequency. This is true as far as the frequency remains low (in this experiment, between 30 and 400 Hz). The flame deformation is created by hydrodynamic perturbations initiated at the base of the flame and convected along the front. When the velocity modulation amplitude is low, the undulations are sinusoidal and weakly damped as they proceed to the top of the flame. When the modulation amplitude is augmented, a toroidal vortex is generated at the burner outlet and the flame front rolls over the vortex near the burner base. Consumption is fast enough to suppress further winding by the structure as it is convected away from the outlet. This yields a cusp formed toward burnt gases. This process requires some duration and it is obtained when the flame extends over a sufficient axial distance. If the acoustic modulation level remain low (typically v /v < 20%),... 

For studies in molecular physics, several characteristics of ultrafast laser pulses are of crucial importance. A fundamental consequence of the short duration of femtosecond laser pulses is that they are not truly monochromatic. This is usually considered one of the defining characteristics of laser radiation, but it is only true for laser radiation with pulse durations of a nanosecond (0.000 000 001s, or a million femtoseconds) or longer. Because the duration of a femtosecond pulse is so precisely known, the time-energy uncertainty principle of quantum mechanics imposes an inherent imprecision in its frequency, or colour. Femtosecond pulses must also be coherent, that is the peaks of the waves at different frequencies must come into periodic alignment to construct the overall pulse shape and intensity. The result is that femtosecond laser pulses are built from a range of frequencies the shorter the pulse, the greater the number of frequencies that it supports, and vice versa. 

A variety of factors differentiating tolerance studies could have contributed to the observed discrepancy. Lower doses are less likely to lead to tolerance than higher doses or will do so less rapidly. The habitual coffee drinkers in some studies may have had different levels or durations of consumption. In the cases of acute dosing, caffeine consumed by subjects outside the laboratory on the day of the experiment may have varied. This is particularly true when some investigators request in advance that subjects abstain from caffeine prior to the experiment, while others do not. Differences in age, gender, and arousal-relevant personality dimensions,... 

Organophosphate insecticides also inhibit RBC-ACHE and PCHE. Inhibition of ACHE in erythrocytes is assumed to mirror inhibition of ACHE in the nervous system, which is the receptor of the toxic action, to some extent. Therefore, measurements of RBC-ACHE and PCHE are used for biological monitoring of exposure to OP insecticides (Maroni, 1986). Inhibitions of RBC-ACHE and PCHE activities are correlated with intensity and duration of exposure, although at different levels for each OP compound. Blood ACHE, being the same molecular target as that responsible for acute toxicity in the nervous system, is a true indicator of effect, while PCHE can only be used as an indicator of exposure. 

In intermediate-duration studies in which lead acetate was administered in the drinking water, the lowest LOAEL was approximately 77 mg lead/kg/day for a 15% decrease in final body (Yokoyama and Araki 1992). Since this was the only dose level tested, it is possible that the true LOAEL was actually lower than 77 mg/kg/day. However, a different 90-day study, also with lead acetate in drinking water reported a NOAEL for body weight of approximately 38 mg lead/kg/day (Kala and Jadhav 1995a). Two studies of similar design in which lead was administered mixed in the food provided conflicting results. 

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