Impulse, definition

It is possible to deteraiine the eumulative residenee time distribution funetion F(t) from either a traeer step-ehange or a traeer impulse response. From its definition, the properties of F(t) are ... 

What this discussion does highlight, however, is that some modification is required to the standard dictionary definition of a neurotransmitter given in the introduction to this chapter, which sees a NT as a substance that transmits the impulse from one neuron to another neuron (or excitable cell). A more comprehensive definition of a NT might be... 

The vertical spring and mass is an example of a stable system and by definition this means that an arbitrary small external force does not cause the mass to depart far from the position of equilibrium. Correspondingly, the mass vibrates at small distances from the position of equilibrium. Stability of this system directly follows from Equation (3.102) as long as the mechanical sensitivity has a finite value, and it holds for any position of the mass. First, suppose that at the initial moment a small impulse of force is applied, delta function, then small vibrations arise and the mass returns to its original position due to attenuation. If the external force is small and constant then the mass after small oscillations occupies a new position of equilibrium, which only differs slightly from the original one. In both cases the elastic force of the spring is directed toward the equilibrium and this provides stability. Later we will discuss this subject in some detail. 

The transport of information from sensors to the central nervous system and of instructions from the central nervous system to the various organs occurs through electric impulses transported by nerve cells (see Fig. 6.17). These cells consist of a body with star-like projections and a long fibrous tail called an axon. While in some molluscs the whole membrane is in contact with the intercellular liquid, in other animals it is covered with a multiple myeline layer which is interrupted in definite segments (nodes of Ranvier). The Na+,K+-ATPase located in the membrane maintains marked ionic concentration differences in the nerve cell and in the intercellular liquid. For example, the squid axon contains 0.05 MNa+, 0.4 mK+, 0.04-0.1 m Cl-, 0.27 m isethionate anion and 0.075 m aspartic acid anion, while the intercellular liquid contains 0.46 m Na+, 0.01 m K+ and 0.054 m Cl-. 

We also see another common definition—bounded input bounded output (BIBO) stability A system is BIBO stable if the output response is bounded for any bounded input. One illustration of this definition is to consider a hypothetical situation with a closed-loop pole at the origin. In such a case, we know that if we apply an impulse input or a rectangular pulse input, the response remains bounded. However, if we apply a step input, which is bounded, the response is a ramp, which has no upper bound. For this reason, we cannot accept any control system that has closed-loop poles lying on the imaginary axis. They must be in the LHP. 1... 

Step and impulse inputs. These discontinuous functions are used particularly in Chapter 5. Their definitions and transforms are ... 

From a well-known result of calculus, the definite integral on the right-hand side is s/n so M is just equal to the quantity of diffusing substance. The present solution is therefore applicable to the case where M grams (or moles) per unit surface is deposited on the plane x=x at t=0. In terms of concentration, the initial distribution is an impulse function (point source) centered at x=x which evolves with time towards a gaussian distribution with standard deviation JlQit (Figure 8. 13). Since the standard deviation is the square-root of the second moment, it is often stated that the mean squared distance traveled by the diffusion species is 22t. 

The autonomic nervous system is by definition that part of the nervous system that innervates smooth muscle, cardiac muscle and glands. It is thus a motor system. Perception arising from the viscera involves pathways similar to those arising from the body surface and skeletal muscle. Thus there are visceral afferent fibres that pass from the viscera to the central nervous system. Such impulses then ascend the spinal cord to the thalamus and are thence relayed to the post-central gyrus of the brain (or sensory cortex). Visceral reflex arcs use visceral afferent fibres to convey impulses to the cord, but the efferent limb of such a visceral reflex is the autonomic nervous system. Although visceral reflexes are under higher central control, it is usually impossible to bring them under the control of the will. 

F. UNIT IMPULSE FUNCTION. By definition, the z transformation of an impulse-sampled function is... 

MAOIs, although effective, are also problematic for routine use in the treatment of BN. First, like the TCAs, MAOIs have a propensity for lowering blood pressure. Additionally, bulimia patients, who are by definition prone to impulsive out of control eating, are not ideal candidates to maintain the strict tyramine-free diet restrictions imposed by MAOIs. Thus, they run a substantial risk of precipitating dangerous hypertensive crises through dietary noncompliance while taking MAOIs. It remains unclear whether the reversible MAOIs such as moclobemide will prove effective in the treatment of BN without the risks associated with other MAOIs. 

Otto Loewi (1873-1961), professor of pharmacology at the University of Graz, awoke one night with a brilliant idea. The next day he went to his laboratory and in one of the most definitive experiments in the history of biology, brought proof of the chemical mediation of nerve impulses. 

Since all tracer entered the system at the same time, t = 0, the response gives the distribution or range of residence times the tracer has spent in the system. Thus, by definition, eqn. (8) is the RTD of the tracer because the tracer behaves identically to the process fluid, it is also the system RTD. This was depicted previously in Fig. 3. Furthermore, eqn. (8) is general in that it shows that the inverse of a system transfer function is equal to the RTD of that system. To create a pulse of tracer which approximates to a dirac delta function may be difficult to achieve in practice, but the simplicity of the test and ease of interpreting results is a strong incentive for using impulse response testing methods. 

Definition of so-called peak-pressure is given in Vol 2 of Encycl, p B181 under BLAST EFFECTS IN AIR, EARTH AND WATER. More detailed description is given by Dunkle under the title Peak Pressure and Impulse (Ref 40, p 363-69) and by Cook (Ref 41) in Chapter 13, Shock Waves in Gaseous and Condensed Media . There (on pp 326-27) is discussed peak-pressure... 

Accdg to definition given in Ref 23, p 3-22 (slightly reworded) It is an initiating explosive - train component fired by an electrical impulse supplied by the energy either stored within the fuze before release of the missile, or generated within the fuze system just prior to or at impact of the fuze. An electric primer serves to initiate the next component of the train which can be either a detonator or delay element... 

Explosion, Impulse in. See Vol 4, p D393-L R. Included is definition of Isp-specific impulse employed in jet propulsion... 

The fault of many books designed to meet this need has been that they were too narrowly recipe books which gave the student little impulse to associate a given preparation with any principle in chemistry, either as an operation or as representative of a class of compounds. Most of the exercises in this book are to be found in some one of the large or small books giving directions for inorganic preparations. Whatever merits this volume may have will lie not so much in the novelty of the examples selected as in the organization of the material around definite methods of procedure and as illustrative of classes of compounds. 

Sodium, potassium, and chloride are electrolytes found in cow s milk for which the Food and Nutrition Board has estimated safe and adequate daily dietary intakes for infants, children and adolescents, and adults (NAS 1980A). Sodium functions in the body to maintain blood volume and cellular osmotic pressure and to transmit nerve impulses (NAS 1980A). The estimated safe and adequate daily dietary intake of sodium is 1100-3300 mg (2.8-8.4 g sodium chloride) for healthy adults (NAS 1980A). The American Medical Association, Council on Scientific Affairs (1979), suggested 4800 mg sodium per day as a tentative definition of moderation in sodium intake. 

The grain size has a definite quantitative effect on the results. As the grain size is increased, resistance decreases. This is probably due to different intensities of the impulse action of the steel ball during comminution of the abradant samples which though of identical weight, differ in grain size. 

Obsessive-compulsive disorder (OCD) is a syndrome characterized by obsessions and/ or compulsions, which together last at least an hour per day and are sufficiently bothersome that they interfere with one s normal social or occupational functioning. Obsessions are experienced internally and subjectively by the patient as thoughts, impulses, or images. According to standard definitions in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), obsessions are intrusive and inappropriate and cause marked anxiety and distress. Common obsessions are listed in Table 9—1. 

Specific Impulse. See definitions under Impulse, Specific in Vol 7, I63-R L35-L. See also under Liquid Propellants in Vol 7, L34-Rto L44-R, and Propellants, Solid in Vol 8, P402-L to P473-L... 

Actually the weight flow rate in the definition of specific impulse should be specified as at sea level and thus g = g and Iap = (F/m) numerically. 

Actually the weight flow rate in the definition of specific impulse should be specified... 

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