Meaningful answers, obtaining

Alternatively, one could use SLLOD equations to do direct simulations, such as shear a system under planar Couette flow and measure the shear stress. As we have already discussed, this approach has been used successfully to calculate a host of transport properties. It is important to remember, however, that direct simulation is often unable to simulate realistic materials at experimentally accessible shear rates. At low shear rates, the nonequilibrium response becomes small compared to the magnitude of the equilibrium fluctuations that naturally arise. The extremely small signal-to-noise ratio would demand prohibitively long simulations before any meaningful answers could be obtained. 

The question remains as to what should be done with such a list. The Solvates procedure generates only a suitable dataset from which we might hope to obtain meaningful answers to the questions that we envisaged at the outset of the study. The particular example of the anhydrous/hydrate dataset is illustrative since it can be compared... 

The experiment has supplied encouraging results on the acceleration of plasma liners and on the concentration of their energy in a small volume. In order that meaningful answers to the fusion problem can be obtained, it is necessary to scale up the apparatus, simplify the injection problem and as already mentioned, provide separate deuterium injection . 

Quantum chemical calculations have become a valuable tool in the research of reactive intermediates. Unfortunately, there is no unique computational method that can be uniformly applied in all cases and give an accurate answer at a practical cost. A variety of computational methods are available, each with its own weaknesses and advantages. The species that are of interest in this chapter and which often have unpaired electrons, pose specific problems in calculating their properties, and some care in choosing appropriate methods is necessary for obtaining meaningful results. In this respect, an excellent guide for calculations on open-shell molecules has been recently published [51]. 

Post-registration clinical studies must be carried out using a written protocol that will provide answers to specific research questions. The protocol must be designed to ensure scientifically meaningful results, and should contain details about study objective, study population, methodology, information to be obtained and data collection method. 

Consider also the data analysis and interpretation that occur once data have been acquired in a trial. First, the appropriate analysis has to be employed as determined by the study design. However, the employment of this analysis alone is not enough to ensure optimum quality answers to the research question. A computationally perfect execution of the appropriate analysis, and the most meaningful interpretation of the results obtained, will not yield optimal answers if the data being analyzed are of less than optimal quality. Therefore, experimental methodology is also of critical importance. 

The object of NMR spectroscopy on proteins, nucleic acids and other complex polymers is to obtain information on their structure and dynamics. Assignment of individual spectral lines discussed in the preceding section is a prerequisite to one s ability to decipher this information. Actually to do so it is also necessary to understand the nature of the structural and dynamic information inherent in each feature of the spectrum. And one is rightfully asked is the nature of this information such that the result will be worth the labor required to obtain a significant set of assignments An important part of the answer to this question is that NMR is the ONLY physical method which can provide any information at essentially atomic resolution on the structure and dynamics of macromolecules in solution, as well as in the solid state. Whatever the limits of this information, it is better than none. Knowledge of these limits, as well as of the nature of spectroscopic information, is nevertheless necessary, both to realize expectations and to avoid conclusions that go beyond the capabilities of the method. The information content and its limits can be meaningfully discussed for each measured parameter separately, and the common features summarized at the end. 

To obtain meaningful results, the questionnaire had to render the complex set of issues as clearly as possible and elicit answers in an effective and unbiased manner. This calls for questions to be simple, with as much... 

The most fundamental chemical questions concerning the molecular weight, atomic co-ordinates and bond strengths of thiols have been answered in the most precise way by careful physical measurements of the translational, rotational and vibrational motions of thiols. Since in any one measurement the number of physical variables usually exceeds the observable parameters, meaningful physical parameters could not have been obtained if measurements had not been made on a series of iso-topicaUy substituted molecules. It is now common practice in molecular spectrometry to site a motional process from several isotopically labelled positions in a molecule. In the following sections, we will briefly describe the physical origin of the isotope effect in mass spectrometry, microwave... 

The last two principles relate to the critical issue of program evaluation (Chapter 18). In safety, the total recordable injury rate (TRIR) is the most popular evaluation number used to rank companies for safety rewards. It is calculated by multiplying the number of workplace injuries by 200,000 and dividing the answer by the total person-hours worked in that time period (U.S. Department of Labor, 1994). What an obvious example of an abstract number with little meaning. The most direct measure of ongoing safety performance comes from behavioral observations and, in Chapters 8,12, and 18,1 recommended ways to obtain meaningful feedback numbers from such process evaluation. 

Before undertaking a program of evaluating inhibitors for effectiveness in mitigating corrosion, one must review the overall problem and determine what is required of the inhibitor, that is, exactly what parameters are to be tested and what factors affect test results. These questions and their answers will help in obtaining meaningful data for selection of the most efficient inhibitor in the environment of interest. The first step is to select the critical environmental conditions of interest and to incorporate them in the test. 

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