Counting methods

Luminol chemiluminescence has also been recommended for measuring bacteria populations (304,305). The luminol—hydrogen peroxide reaction is catalyzed by the iron porphyrins contained in bacteria, and the light intensity is proportional to the bacterial concentration. The method is rapid, especially compared to the two-day period required by the microbiological plate-count method, and it correlates weU with the latter when used to determine bacteria... 

Step Count Methods These methods, used for order-of-magnitude estimates, are based on the definition of the functional units required to carry out the process. A functional unit is a signifi-... 

In general, the step count method of estimation can be apphed to any special situation to derive a model equation for that particular industry or group of processes. 

The parts count method is suitable for early design phase reliability prediction. The method uses information on generic types, quality levels, and environment. The latter two effects are considered with the application of specified factors. The failure rates for both methods are calculated using the same generic expressions. 

Because physiological deterioration is generally accompanied by an increase in bacterial population, as pointed out by Nielsen, Wolford, and Campbell (33), estimation of bacterial numbers might serve as the basis of a test for condition. Obviously, the plate count method is not adaptable because of the time limitations imposed. Direct microscopic count would be much more appropriate, especially if a positive field count were substituted for cell count as suggested by Wolford (39). 

In the pulse counting method, each photoelectron pulse arriving at the phototube anode is processed. The pulses are amplified and then used to trigger a pulse generator. The output pulses from the generator are integrated and displayed on a recorder. 

West Antarctica, but not at the very dry sites in East Antarctica. In addition to such continual counting methods, one can determine the absolute age of ice by identifying the fallout from volcanic eruptions of known age. 

There are two methods for counting electrons formal charge and oxidation state. These two counting methods actually represent two flipsides of the same coin. To calculate formal charge, we treat all bonds as covalent, regardless of whether they are or not ... 

This evaluation conveniently be classified into suspension tests (section 3.1) and counting methods, although the latter themselves use suspensions of microorganisms and hence are referred to here as quantitative suspension tests (section 3.2). 

Kucera J, Vobecky M, Soukal L, Zakoucky D, and Venos D (1997) Low level determination of thallium in biological and environmental reference materials by RNAA using several counting methods. J Radioanal Nud Chem 217 131-137. 

Concerns that diagenetic alteration could affect measured °Th ages of corals have existed since the early applications using alpha-counting methods. Thurber et al. (1965) offered the following list for reliable coral °Th ages a) no evidence of recrystallization, b) uranium concentration of 3 ppm, c) p°Th/ Th] of > 20, d) of 1.15 ... 

Clearly, step counting methods can only, at best, give a very approximate idea of the probable cost of a plant. They are useful in the conceptual stage of process design, when comparisons between alternative process routes are being made. 

Half-lives of two pesticides were estimated using the assumption that the decay was a first-order process. Half-lives were 28 8.5 days and 12 3.4 days for thiophanate-methyl and methiocarb, respectively. Crop volume was not a significant determinant of exposure using a grid count method. This was probably due to a large variation in the results with this method. 

Steady-state fluorescence spectra, fluorescence quantum yield (F) and lifetimes (tf) of DTT 15 and DTP 23a were estimated as shown in Table 8. F for DTT is higher than DTP. F for DTP is very small and it was difficult to estimate an accurate fluorescence lifetime by the photon counting method due to weak fluorescence. It is noted that the for DTP depends largely on the solvent and is 7.7 x 10-5 in acetonitrile. This low F value has been attributed to an addition reaction with the solvent. 

Homma, Y. and Y. Murakami, Study on the Applicability of the Integral Counting Method for the Determination of Ra in Various Sample Forms Using a Liquid Scintillation Counter,. 1. Radioanal. Chem. 36 173-184 (1977). 

Khan, A. and C.R. Phillips, A Simple Two-Count Method for Routine Monitoring of Radon and Thoron Progeny Working Levels in Uranium Mines, Health Phys. 50 381-388 (1986). 

Reproducibility testing demonstrated that protein abundance measured using the spectral counting method exhibited a Pearson correlation R2 value >0.99 and a coefficient of variance of 14% (Fig. 20.6). 

The overall rate of disappearance of 64Cu is the sum of three processes, but by making use of different types of counting methods, it is possible to separate the rates of the processes. 

Badosa E, Trias R, Pares D, Pla M and Montesinos E. 2008. Microbiological quality of fresh fruit and vegetable products in Catalonia (Spain) using normalised plate-counting methods and real time polymerase chain reaction (QPCR). J Sci Food Agric 88(4) 605-611. 

Baskaran et al. [30] pumped seawater at 35l/min and collected dissolved species on cartridges prior to determining radium, thorium, and lead by y counting methods. 

The photon-counting method preserves the temporal structure of the signal. 

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