Theses Searches

Answers from aH of these searches contain CAS Registry Numbers. Answer sets may be combined, using the Boolean operators AND, OR, or NOT, with other answer sets or with text terms, such as names or molecular formulas. Any answer set also may be used to define subsets of the file for subsequent stmcture searching. Answer sets of up to 10,000 Registry Numbers from any type of search in this file may also be used as search terms in other files, such as the CA or CAOLD files (53). 

Research chemists cannot do these searches independently. There are a number of tools designed to identify and evaluate hazards. Several of these "identification tools are described below. 

Most studies concentrated on the presence of super Li rich giants in GC. But these Li-rich giants have been quite elusive only a few have been found despite extensive searches which may have included hundreds of stars (Kraft et al. 1999, Smith et al. 1999, Pilachowski et al. 2000 ). Since Li-rich giants are treated in another contribution (De la Reza, these proceedings), I will just summarize these searches by saying that Li-rich giants are not common among GC. 

The most serious problem with MM as a method to predict molecular structure is convergence to a false, rather than the global minimum in the Born-Oppenheimer surface. The mathematical problem is essentially still unsolved, but several conformational searching methods for approaching the global minimum, and based on either systematic or random searches have been developed. These searches work well for small to medium-sized molecules. The most popular of these techniques that simulates excitation to surmount potential barriers, has become known as Molecular Dynamics [112]. 

The optimum seeking methods which have been found to be particularly useful are the modified Fibonacci search (search by golden section) for one-dimensional searches and the Hooke-Jeeves search for multi-dimensional searches. Beveridge and Schechter (8) give a complete description of these searches. 

Kuester and Mize (9 ) have listed computer programs written in Fortran IV for both of these searches. 

If a car is impounded for a valid reason, police may conduct inventory searches. If these searches yield evidence of a crime, the evidence wiU likely sustain a challenge to the legality of the search. 

Web sites for process equipment and instrumentation, such as www.globalspec.com and www.thomasnet.com, are valuable tools when selecting a flowmeter. These search engines can scan the flowmeters manufactured by more than 800 companies for specific products that meet the user s specifications. Table 10-4 was based in part on information from these web sites. Note that the accuracies claimed are achieved only under ideal conditions when the flowmeters are properly installed and calibrated for the apphcation. 

Finally, what mathematical criteria are used in these searches In other words, as the computer goes through sets of trial values (angles or coordinates) for... 

As an example I cite our early searches on the chemical structure properties indole and ethyiamine and the medical use properties sympathomimetic and parasympathomimetic 8). These searches revealed two sets ot intersecting hyperspace axes. One ot these intersections contains compounds with ethyiamine structures (Property A in Table IV) which have the medical use property sympathomimetic the other cluster indicates organic ammonium ions... 

The dumbest of these search methods by some distance is one in which colours are chosen for matching completely at random. In a random search (Fig. 2a) a colour is chosen blindly from the wheel for comparison with the paint chip. If the colours match, the search is over, but if there is no match, another colour is chosen at random and the process is repeated. This kind of search has almost no merit beyond simplicity. Even in the small search space of this problem it is inefficient, while for large spaces the probability of success falls to near zero. Furthermore, the search may revisit points it has already checked, which is unproductive. (This is avoided in a TABU search, in which a tally is kept of points previously visited, but maintaining a TABU list adds computational overhead which becomes increasingly onerous as the search progresses and cannot pretend to rescue what is a very poor method.)... 

Another tedious and time-consuming task can be literature searches. We find these searches can be handled quite easily by computer. A person skilled in searching the many databases available can do so in a very short time. 

---