Choice, parental

Olfactory signals in mammals provide information which can be used for mate choice, parent-offspring and kin recognition (Brown, 1979 Brown Macdonald, 1985). Olfactory cues found in the urine of mice and rats have been frequently associated with... 

If there is a choice among heterocyclic systems, the parent compound is decided in the following order of preference ... 

When only one carbonyl or hydroxyl group is to be blocked in a multifunctional compound, the choice of the protecting group will be determined by the ease with which the group can be introduced selectively into the parent molecule. 

The application of double Fischer indolization has been demonstrated to provide larger amounts of the indolocarbazole 4 from the treatment of the hisphenylhydra-zone 151 with aqueous sulfuric acid (63JCS2504). A considerably more efficient protocol has been devised by Robinson, who obtained 4 in 35% yield on treatment of 1,4-cyclohexanedione bisphenylhydrazone (151) in a mixture of acetic acid and sulfuric acid (63JCS3097). In spite of many recent developments, this is still the method of choice for the preparation of the parent system 4 as the starting materials are cheap and readily available. Cyclization of 151 in ethanol-water containing... 

The insect s choice of food may be governed to a considerable extent, as ours is, by attractants and repellents. In many instances, the actual insecticidal action of plant extractives may be due primarily to an artificially high level of application, while, in fact, the parent plants are only repellent in the field. This repellency may appear to be resistance on the part of the plant, and the chemistry of such resistance factors has begun to receive much-needed attention. For example, Smissman and his coworkers have examined the chemical basis for the inherited resistance of some strains of corn to attack by the European corn borer. 6-Methoxybenzoxazolinone (X) was isolated (2, SO) and shown to be one of the principal resistance factors, and a number of synthetic analogs were found to... 

Two general methods can be used, the choice depending on whether the parent ester is a dialkyl- or a monoalkylacetate. Many functional variations can be tolerated, including monosubstituted malonates, and y- and (5-lactones (5). 

There are countless other reactions, many like these and others rather different, but the idea in every case is the same. A sudden flash of light causes an immediate photo-excitation chemical events ensue thereafter. This technique of flash photolysis was invented and applied to certain gas-phase reactions by G. Porter and R. G. W. Nor-rish, who shared with Eigen the 1967 Nobel Prize in Chemistry. High-intensity flash lamps fired by a capacitor discharge were once the method of choice for fast photochemical excitation. Lasers, which are in general much faster, have nowadays largely supplanted flash lamps. Moreover, the laser light is monochromatic so that only the desired absorption band of the parent compound will be irradiated. 

Carb-2. Parent monosaccharides 2-Carb-2.1. Choice of parent structure... 

The parent that includes the functional group most preferred by general principles of organic nomenclature [13,14], If there is a choice, it is made on the basis of the greatest number of occurrences of the most preferred functional group. Thus aldaric acid > uronic acid/ketoaldonic acid/aldonic acid > dialdose > ketoal-dose/aldose > diketose > ketose. 

Systematic names for individual dialdoses are formed from the systematic stem name for the corresponding aldose (see 2-Carb-8.2), but with the ending odialdose instead of ose , and the appropriate configurational prefix (Chart I). A choice between the two possible aldose parent names is made on the basis of 2-Carb-2.2.2. 

Chart V. Choice of parent in branched-chain monosaccharides. In the first names given for examples 1,3 and 4, side-chain configuration is specified by use of R and S. This approach is generally preferred in all but the simplest cases, as less open to misinterpretation. 

Names of individual aldaric acids are formed by replacing the ending -ose of the systematic or trivial name of the parent aldose by -aric acid . Choice between possible names is based on 2-Carb-2.2.2. 

Fischer projection of acyclic form, 56-57 glycosides, 132-135 C-glycosyl compounds, 139-140 N-glycosyl derivatives, 137-139 glycosyl halides, 136-137 glycosyl residues, 125 isotopic substitution and isotopic labelling, 91 me so forms, 59 optical rotation, 59 parent structure choice, 53... 

If there are stiU more choices of possible parent chains (as there are in this case), then we look for the chain that also includes the double bond (if there is one in the compound). In our case, there is a double bond, and this rule determines for us which chain to use ... 

Next we need to name the parent. We locate the longest chain that includes the functional group and double bond. In this example, it is an obvious choice. The parent has 7 carbon atoms, so the parent is -hept-. 

This could be a good choice if you live nearby and can ask a parent to take charge. 

The construction starts at the root node of the tree, where all the available (x, y) pairs are initially placed. One identifies the particular split or test, s, that maximizes a given measure of information gain (Shannon and Weaver, 1964), 0(.s). The definition of a split, s, involves both the choice of the decision variable and the threshold to be used. Then, the (x, y) root node pairs are divided according to the best split found, and assigned to one of the children nodes emanating fi-om it. The information gain measure, 0is), for a particular parent node t, is... 

However, there is no general requirement that enforcement methods need to monitor all metabolites of an active ingredient. The primary purpose of enforcement methods is to detect violations of good agricultural practice. For this purpose, residue levels found in samples from the market (so-called Market Basket Surveys) have to be compared with MRLs, which are derived from residue concentrations found in supervised trials. It is not necessary for this comparison to be based on the total pesticide residue. Most often the choice of a single compound (e.g., parent or primary metabolite) as a marker of the total pesticide residue is more feasible. Method development and the later method application are much easier in that case. Only for intake calculation purposes, e.g., when the daily intake of pesticide residues (calculated from the results... 

This technique is used mainly for nonpolar compounds. Typically a small aliquot of soil (10-30 g) is dried by mixing with sodium sulfate prior to extraction. Next, the sample is extracted with a solvent for 10-20 min using a sonicator probe. The choice of solvent depends on the polarity of the parent compound. The ultrasonic power supply converts a 50/60-Hz voltage to high-frequency 20-kHz electric energy that is ultimately converted into mechanical vibrations. The vibrations are intensified by a sonic horn (probe) and thereby disrupt the soil matrix. The residues are released from soil and dissolved in the solvent. 

The second compatibility condition can also be fulfilled easily by an appropriate choice of the parent molecules Mk with respect to the selection of the nuclear families fk of the various fragments within the target macromolecule M. 

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