Underlying Problems

A basic problem of microstructural fracture theories involving chain scission is clearly an elucidation of this descrepancy. Such a clarification can only be attempted by widening the scope and by including other experimental observations. Three principal questions must be raised before supporting or discarding a chain scission fracture hypothesis  

The discussion of the underlying problem of the nature of the primary molecular processes of damage, their interaction and possible propagation has been initiated and constantly stimulated through the various detailed studies carried out in the A. F. Ioffe Physicotechnical Institute in Leningrad by S. N. Zhurkov and his colleagues [3—33]. The individual problems attacked concern 

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Motivation Unit tests require a substantial investment in time and resources to complete successfully. This is the case whether the test is a straightforward analysis of pump performance or a complex analysis of an integrated reactor and separation train. The uncertainties in the measurements, the likelihood that different underlying problems lead to the same symptoms, and the multiple interpretations of unit performance are barriers against accurate understanding of the unit operation. The goal of any unit test should be to maximize the success (i.e., to describe accurately unit performance) while minimizing the resources necessary to arrive at the description and the subsequent recommendations. The number of measurements and the number of trials should be selected so that they are minimized. 

Personnel (training) ensures all staff know how the systems should work and equips them to identify breakdowns and help identify and correct any underlying problems. 

The analysis of performance provides a powerful technique for identifying potential for improvement. As discussed in the previous chapter, trends can be spotted and action taken to identify and correct any unwanted development. Additionally, analysis of data can help with the identification of underlying problems. For example, a higher than average number of eye injuries at a particular facility might justify further investigation. 

Some resource economists fervently support the concept of sustainability. Others argue that the principle is less coherent, comprehensible, and compelling than prior concepts, particularly the core economics principle of efficiency. For economists, the choice of terminology is sccondaiy. The priniai y concern is resolving the underlying problems of possible market inefficiencies and the ability of governments to cure them. 

The underlying problem in testing the validity of the additivity principle in corrosion, mineral extraction, and electroless plating is that the electrode metal itself forms part of one of the half-reactions involved, e.g., zinc in equation (5) and copper in equations (8) and (12). A much better test system is provided by the interaction of two couples at an inert metal electrode that does not form a chemical part of either couple. A good example is the heterogeneous catalysis by platinum or a similar inert metal of the reaction... 

Table 1. The reasons for the apparent breakdown of the original principle have included chemical interaction between one couple and an intermediate species of the other, changes produced in the structure of the electrode surface and, most common of all, adsorption on the surface of a component of one couple that affected the electrode kinetics of the other. The underlying problem in these cases has been the untenable premise that each couple acts quite independently of the other and is not affected by the other s presence. However, as many of these studies have shown, the premise of additivity still applies whenever the interactions have been allowed for by carrying out the electrochemical experiments in an appropriate fashion. The validity of adding or superimposing electrochemical curves can therefore be considerably extended by restating the principle as follows ...

Diarrhea is not a disease in itself but rather a symptom of some underlying problem. It is a condition marked by increased stool frequency (usually greater than 3 times daily), stool weight, liquidity, and decreased consistency of stools compared to a patient s usual pattern. Acute diarrhea is defined as diarrhea lasting for 14 days or less. Diarrhea lasting more than 30 days is called chronic diarrhea. Illness of 15 to 30 days is referred to as persistent diarrhea.1 2 3 4 5 6 7... 

Additionally, the risk of a subsequent seizure must be determined. If there is an underlying treatable cause, such as hyponatremia or a CNS infection, the risks of another seizure and the development of epilepsy are very small. In these cases, the only pharmacotherapy that is necessary is to correct the underlying problem and possibly short-term use of an AED. Risk factors for repeated seizures in patients without an underlying disorder include ... 

Shock refers to conditions manifested by hemodynamic alterations (e.g., hypotension, tachycardia, low cardiac output [CO], and oliguria) caused by intravascular volume deficit (hypovolemic shock), myocardial pump failure (cardiogenic shock), or peripheral vasodilation (septic, anaphylactic, or neurogenic shock). The underlying problem in these situations is inadequate tissue perfusion resulting from circulatory failure. 

Therefore, we derided to initiate a program directed towards the development of a tita-nocene-catalyzed epoxide opening [3c]. Since titanocene dichloride is formed in the stoichiometric reaction after the protic quench, the challenge to be met is the regeneration of the redox-active species in situ, the fundamental requirement for a catalytic reaction. This underlying problem is depicted in Scheme 12.12. 

In this sub-Section the different research areas concerning each of the three selected case studies are shown. The data is collected from the primary process and part of the secondary process, and subsequently analysed to find the underlying problems present in the tertiary process. The primary process and that part of the secondary process which interacts directly with the primary process, e.g. maintenance, internal transportation, etc., is called the operational process and is the area where the required data is collected from. This operational process is shown in this sub-Section by showing the primary processes and secondly by presenting the interacting secondary processes. The tertiary processes will be presented when discussing the analysis of the data retrieved from the operational processes in sub-Section 7.2.4. 

Frequently, MCS involves imbalances in one s nervous, immune, and endocrine systems, and impaired detoxification abilities. Conditions such as CFIDS (Chronic Fatigue Immune Dysfunction Syndrome), fibromyalgia, and Candida Syndrome are frequently found in people with MCS. It is not yet known whether these are separate diseases or whether they represent different manifestations of a common underlying problem. 

Although I have mentioned other barriers and problems in drug development and some of the reasons for them, FDA thinks there might be one underlying problem that is addressable now, that does not require waiting decades for basic biomedical science to become truly predictive. We believe that societal investment in the research and development... 

Identify Other Causes. As has already been stressed, the first step in developing a treatment plan is to identify and treat any underlying problem that may be triggering the sleep disturbance. 

Generate a trial solution to the underlying problem. For combinatorial library design, a random selection of a subset of building blocks is generated. 

Calculate the value of a fitness function (Fcurr) that characterizes the quality of the trial solution to the underlying problem (e.g., the diversity or predicted activity of the combinatorial library built upon the selection of building blocks from step 1). 

For doctors and patients, psychopharmaceuticals are often the simplest way out of a difficult situation drugs suppress a few acute symptoms but do not lead to a permanent solution for the basic underlying problems. 

Importantly, recognize that the sensitivity problem is a linear equation for the sensitivity coefficients regardless of whether the original problem is linear or nonlinear. Once the solution to the underlying problem is determined, the sensitivity coefficients can be computed efficiently, exploiting the inherent linearity [57,102,110,232,321], There is recent sensitivity software by Petzold that builds on the DASSL family of codes [258],... 

Sensitivity analysis has the potential of generating an enormous (perhaps overwhelming) amount of data. The sensitivity coefficients are an m x n matrix, where m is the number of dependent variables in the underlying problem and n is the number of parameters in the analysis. Moreover the sensitivity matrix varies as a function of time. Even for modest-sized problems it is essential to have software and graphics that automatically assist processing and interpreting the sensitivity coefficients. 

Because the underlying problem in Parkinson disease is a deficiency of dopamine in the basal ganglia, simple substitution of this chemical would seem to be a logical course of action. However, dopamine does not cross the blood-brain barrier. Administration of dopamine either orally or parenterally will therefore be ineffective because it will be unable to cross from the systemic circulation into the brain where it is needed. Fortunately, the immediate precursor to dopamine, dihydroxyphenylalanine (dopa Fig. 10-2), crosses the blood-brain barrier quite readily. Dopa, or more specifically levodopa (the L-isomer of dopa), is able to cross the brain capillary endothelium through... 

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