Historical-costs approach

If the accounting is done on the basis of historical cost, capital is maintained only in terms of money values. A profit is recorded when the money value of the net assets at the end of the year exceeds the money value of the net assets at the start of the year. Alternative approaches might be to say that the productive capacity of the compaity must be maintained or that the purchasing power of the net assets must be maintained either of these approaches seems more realistic than simply maintaining the money value of the capital. Nevertheless, the practical difficulties of such approaches are considerable. 

Historically, the discovery of one effective herbicide has led quickly to the preparation and screening of a family of imitative chemicals (3). Herbicide developers have traditionally used combinations of experience, art-based approaches, and intuitive appHcations of classical stmcture—activity relationships to imitate, increase, or make more selective the activity of the parent compound. This trial-and-error process depends on the costs and availabiUties of appropriate starting materials, ease of synthesis of usually inactive intermediates, and alterations of parent compound chemical properties by stepwise addition of substituents that have been effective in the development of other pesticides, eg, halogens or substituted amino groups. The reason a particular imitative compound works is seldom understood, and other pesticidal appHcations are not readily predictable. Novices in this traditional, quite random, process requite several years of training and experience in order to function productively. 

Based on many of the advances described above in electrochemical approaches to immunoassay, it is tempting to conclude that commercialization of some of the approaches is imminent. This may be true, but the historical use of optical methods for many clinical chemistry tests coupled with their rapidly growing use in immunoassay is a difficult barrier for any radically different method to overcome, though electrochemical sensors have become more important in the clinical chemistry laboratory over the last decade. In any event, to be successful ECIA methods will have to demonstrate clear superiority over existing and emerging technologies in both cost and performance. Some of the more recently described approaches such as those using enzyme amplified amperometric detection and ecLIA appear... 

Acupressure and acupuncture have been investigated based on the theory that certain points on the body control specific bodily functions.11 The P6 (Neiguan) point on the inside of the wrist has been used historically by acupuncturists to treat nausea and vomiting. While this approach seems safe and cost effective, efficacy data in the treatment of NVP are conflicting. The majority of studies showed a benefit to this approach, but the studies had methodologic flaws.9,11,12... 

Pll The asymmetric synthesis of a-amino acids and derivatives is an important topic as a result of their extensive use in pharmaceuticals and agrochemicals and as chiral ligands. Many highly enantioselective approaches have been reported. Industrial production of a-amino acids via the Strecker reaction is historically one of the most versatile methods to obtain these compounds in a cost-effective manner, making use of inexpensive and easily accessible starting materials. (From Boesten et al., 2001)... 

Some new work has been done here which shows the effects of solvents exposure. A new study illustrates a simple method of detoxification using heat chamber depuration (sauna), and raises awareness in the practice of medicine of the importance of taking an environmentally oriented historical approach. The connection between symptoms of chronic degenerative diseases and environmental and/or nutritional factors is missed in many cases due to lack of obtaining an environmentally oriented medical history. Taking such a history and dealing with the cause of illness using avoidance and/or appropriate therapy is preventive and cost-effective for both the patient and society (Krop, 1998). 

The overall problem, from sulfur in a raw gas through sulfur recovery and tail gas treating, has historically been addressed by a case study approach. In this approach, each plant section is optimized based upon predetermined subsystem interfaces. A preferred approach, rather, is to evaluate the entire system analytically, allowing the interfaces between the subprocesses to float, to determine the overall cost-effective,approach. In this technique, compromises are taken in each of the unit processes so that the total system operates more effectively. 

While an intensity profile at the detector as a function of retardation may be acquired in a step-scan mode, two major drawbacks affect this method of interferogram acquisition. First, the mirror(s) requires stabilization times with mirror inertia and time constants of the control loop determining this parameter in achieving a given optical retardation. Second, additional hardware and control mechanisms need to be incorporated into the spectrometer, thus increasing instrument cost and complexity. In certain cases, however, the utility of a step-scan instrument justifies this additional expense. Historically, the step-scan approach was favored with slow detectors. With the advent of fast detectors and electronics, step-scan interferometry became... 

Historically, L-aspartic acid was produced by hydrolysis of asparagine, by isolation from protein hydrolysates, or by the resolution of chemically synthesized d,L-aspartate. With the discovery of aspartase (L-aspartate ammonia lyase, EC 4.3.1.1),57 fermentation routes to L-aspartic acid quickly superseded the initial chemical methods. These processes are far more cost effective than the fermentation routes, and aspartate is now made exclusively by enzymatic methods that use variations of the general approach outlined in Scheme 2.19.53-57-65... 

Laboratory experiments, transport modeling, field data, and engineering cost analysis provide complementary information to be used in an assessment of the viability of an MNA approach for a site. Information from kinetic sorption/ desorption experiments, selective extraction experiments, reactive transport modeling, and historical case analyses of plumes at several UMTRA sites can be used to establish a framework for evaluation of MNA for uranium contamination (Brady et al, 1998, 2002 Bryan and Siegel, 1998 Jove-Colon et al, 2001). The results of a recent project conducted at the Hanford 100-N site provided information for evaluation of MNA for a °Sr plume that has reached the Columbia River (Kelley et al, 2002). The study included strontium sorption-desorption studies, strontium transport and hydrologic modeling of the near-river system, and evaluation of the comparative costs and predicted effectiveness of alternative remediation strategies. 

Chemistry. Isolation of thiamine from natural sources (hce bran, yeast extracts, or wheat germ) is only of historical interest. Production by bioprocesses is not cost-effective at present. AH of the thiamine produced worldwide is manufactured by chemical processes operated at moderately large scale. Two major synthetic routes have been used alkylation of a preformed thiazole, or constmction of the thiazolium salt from a pyrimidine carrying the ultimate thiazole nitrogen (9,40). The latter approach is now generally preferred for manufacturing. 

Instead, interest is largely focused in two areas wood modification and heat treatment. Both approaches are more expensive than conventional pressure treatments and historically their use has been limited. However increasing concerns about the environmental effects of biocides, and the increasing costs of the biocides themselves has made these alternative approaches more attractive. Apart from Europe, currently they are limited to niche markets. 

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