Delayed response performance

Schneider JS, Sun ZQ, Roeltgen DP. 1994. Effects of dopamine agonists on delayed response performance in chronic low-dose MPTP-treated monkeys. Pharmacol Biochem Behav 48 235-240. 

Power ampliher bandwidth has a signihcant effect on modulation performance. Available bandwidth determines the amplitude response, phase response, and group delay response. Performance tradeoffs must often be considered in the design of a cavity ampliher, including bandwidth, gain, and efhciency. 

The period of the test depends on whether long- or short-term effects are of interest. Acute toxicity is the effect of a single exposure or a series of exposures close together in a short period of time. Chronic toxicity is the effect of multiple exposures occurring over a long period of time. Chronic toxicity studies are difficult to perform because of the time involved most toxicological studies are based on acute exposures. The toxicological study can be complicated by latency, an exposure that results in a delayed response. 

Sawaguchi T, Goldman-Rakic PS. 1994. The role of Dl-dopa-mine receptor in working memory Local injections of dopamine antagonists into the prefrontal cortex of rhesus monkeys performing an oculomotor delayed-response task. J Neurophysiol 71 515-528. 

Ljungberg T, Apicella P, Schultz W (1991) Responses of monkey midbrain dopamine neurons during delayed alternation performance. Brain Res 567 337-341. 

Pharmacological manipulation of DA, within mesostriatal, as well as mesofrontal domains, has profound effects on performance in spatial working memory tasks in both rodents and monkeys. Early work (reviewed by LeMoal and Simon, 1991) demonstrated that 6-OHDA-induced lesions of the meso-accumbens or meso-striatal, as well as the meso-cortical DA projections led to impaired delayed alternation performance in rats. However, there is a question of whether the capacity to hold on-line the location of the previous goal or choice response has been impaired or whether other behavioral capacities, such as the inhibition that is normally required for the spontaneous alternation of choices is disrupted, leading to perseverative responding. 

Brozoski et al. (1979) performed a landmark study on the role of PFC DA in working memory function in monkeys. These investigators used a delayed response type procedure to show that 6-OHDA-induced depletion of DA in the principal sulcus of the dorsolateral prefrontal cortex in macaques produced an impairment as profound as ablation by aspiration of the region itself. In contrast, depletion of either noradrenaline or 5-HT in the prefrontal cortex had little effect. Convincing evidence for a specific role of DA came from... 

Some information about cyanide toxicity in humans is available from research on accidental exposures—for example in industrial accidents—although the usefulness of these data is limited because exposure durations and concentrations are often not known or not reported, because small numbers of individuals were exposed, and because other details, such as possible exposure to other chemicals, also are often not reported. Scrutiny of blood cyanide concentrations in victims of cyanide poisoning could be misleading for the purposes of characterizing dose-response relationships, depending on the length of the delay before performing the assay (Chaturvedi et al. 1995). 

Reserpine [0.1 mg/kg intramuscularly (i.m.)] or yohimbine (0.01 mg/kg i.m.) induces significant impairments in the monkey s ability to perform the delayed response task. HA at a dosage of 0.01 mg/kg i.m. for the yohimbine-treated monkeys markedly improved the memory impairments. The effects exhibited an inverted U-shaped dose-response pattern. The data suggest that HA may improve working memory via an adrenergic mechanism. ... 

Figure 8 Effects of 7 mg kg trimethyltin on delayed alternation performance. Lower accuracy values were evident in TMT-treated rats at all delay values, but no impairment was seen in the zero-second delay condition, consistent with a specific effect on memory function. (Reproduced from Bushnell PJ (1988) Effects of delay, intertrial interval, delay behavior and trimethyltin on spatial delayed response in rats. Neurotoxicology and Teratology 10 237-244, with permission from Elsevier.)...

Part of the work performed on a sample will be converted irreversibly into random thermal motion by movement of the molecules or molecule segments. This loss passes through a maximum at the appropriate transition temperature or relaxation frequency in the associated alternating mechanical field (torsion pendulum test). A similar effect is obtained by the delayed response of the dipoles with dielectric measurements. Therefore, dielectric measurements can be made only on polar polymers. According to the... 

This reaction stops in alkaline electrolytes because of the formation of an insoluble film of magnesium hydroxide on the electrode surface which prevents further reaction. Acid tends to dissolve the film. An important consequence of the film on magnesium elecfrodes (see also Chap. 9) is that there is a delayed response to an increase in the load because of the need to disrupt the film to create new bare surfaces for reaction. Pure magnesium anodes usually do not give good cell performance, and several magnesium alloys have been developed for use as anodes tailored to provide the desired characteristics. 

Moukhles etaL (1994) transplanted dopamine-rich ventral mesencephalic suspension in a partially dopamine-depleted striatum of rats performing a reaction-time motor task. In the lesion group premature responses and delayed responses were seen. In the grafted animals the premature responses improved totally, the number of delayed responses remained high. 

Time-Delay Compensation Time delays are a common occurrence in the process industries because of the presence of recycle loops, fluid-flow distance lags, and dead time in composition measurements resulting from use of chromatographic analysis. The presence of a time delay in a process severely hmits the performance of a conventional PID control system, reducing the stability margin of the closed-loop control system. Consequently, the controller gain must be reduced below that which could be used for a process without delay. Thus, the response of the closed-loop system will be sluggish compared to that of the system with no time delay. 

Decreases the production of lymphocytes and eosinophils in the blood by causing atrophy of the thymus gland blocks the release of cytokines, resulting in a decreased performance of T and B monocytes in the immune response. (This action, coupled with the anti-inflammatory action, makes the corticosteroids useful in delaying organ rejection in patients with transplants.)... 

To visualize the sensitive response of the time-dependent forward scattering to small changes of hyperfine parameters, the time spectra for asymmetry parameters T] = 0.0, 0.2, and 0.5 (keeping aU other parameters the same) were simulated (Fig. 9.22). Comparable sensitivity was achieved for other hyqrerfine parameters, provided the measurements are performed to high enough delay times. 

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