Accurate Timing

With the short pulses available from modem lasers, femtosecond time resolution has become possible [7, 71, 72 and 73], Producing accurate time delays between pump and probe pulses on this time scale represents a... 

Neuhauser D and Baer M 1990 A new accurate (time independent) method for treating three-dimensional reactive collisions the application of optical potentials and projection operators J. Chem. Phys. 92 3419... 

The methods in which iodine is used as a catalyst for the reaction between ceric sulfate and nitrite or arsenite (86,87) are capable of determining smaH amounts of iodine. However, these catalytic methods are deHcate and require accurate timing, carefiH temperature control, and special apparatus. 

The Centralized Reliability Data Organization (CREDO) is maintained at ORNL to provide a central computer-based source of accurate, timely data and information for use in reliability, availability and maintainability analyses of liquid metal reactors (LMRs). CREDO is a component-based system, that addresses a comprehensive list of 45 genetic components that are representative of all components found at LMRs. 

Considering the numerous applications, heart-cut LC-LC has convincingly proven its value. Nevertheless, in LC-LC specific method development is generally needed for each analyte. Moreover, heart-cut procedures require accurate timing and, therefore, the performance of the first analytical column in particular should be highly stable to thus yield reproducible retention times. This often means that in LC-LC some kind of sample preparation remains necessary (see Table 11.1) in order to protect the first column from proteins and particulate matter, and to guarantee its lifetime. 

The form or format of the notebook is not as critical from a GLP compliance standpoint as the completion of the record in an accurate, timely, readable, and attributable manner. Company and PI conventions typically have evolved into cost-effective and very efficient data notebooks for field residue trials. These notebooks contain the actual raw data for the trial and once begun become extremely valuable legal parts of the study record. The notebooks should be audited by QA during the field phase of the study as well as at the end of the trial before the notebook is returned to the sponsor organization. The quality of the trial is easily refiected in the quality of the field notebook at the end of the season. 

It has been shown that the rate constants obtained from the slopes of In [intensity] versus plots approximate the rates of the highest-probability matrix sites. Hence, workers have utilized the temperature dependence of these values, or other empirically derived stretched exponential time dependencies, to estimate low temperature Arrhenius plots. The validity of such methods, however, depends critically on obtaining accurate time-dependence data on the fastest matrix sites, which is increasingly difficult as temperatures are raised. 

It must be assumed that urine collections were accurately timed and that complete urine specimens were obtained at each collection time. It is also assumed that the assay procedure is accurate and reproducible. 

Multi-static radar is usually combined with the net-centric approach to data exchange. All sensor sites have to be connected by high-throughput, self-configuring data links. The data links should also provide a very stable clock to make all processing coherent, and very accurate time data to synchronize all events in the distributed system. 

The need to provide accurate, timely, transparent and credible information so that decision-makers at least have a factual basis from which to operate. Without a continuing commitment from industry to far greater transparency -especially in matters that are perceived as impinging on public or environmental health - our industry will be unsustainable. Trust me - I m a businessman works about as well as Trust me - I m a politician . Even Trust me - I m a journalist works better ... 

For primary members (external walls, roof slabs, etc.), the load computation is performed in accordance with Chapter 3. Loads on supporting, or interior members, are determined either by I. the tributary area method or 2, from a computed dynamic reaction. In the tributary area method, external blast pressures are multiplied by the exterior surface area tributary to a support location. The resulting force is then applied to the next member. Dynamic reactions result from a numerical time history analysis (refer to Section 6.5.3) and provide a more accurate time-varying load on the supporting member. 

The rotational relaxation of DNA from 1 to 150 ns is due mainly to Brownian torsional (twisting) deformations of the elastic filament. Partial relaxation of the FPA on a 30-ns time scale was observed and qualitatively attributed to torsional deformations already in 1970.(15) However, our quantitative understanding of DNA motions in the 0- to 150-ns time range has come from more accurate time-resolved measurements of the FPA in conjunction with new theory and has developed entirely since 1979. In that year, the first theoretical treatments of FPA relaxation by spontaneous torsional deformations appeared. 16 171 and the first commercial synch-pump dye laser systems were delivered. Experimental confirmation of the predicted FPA decay function and determination of the torsional rigidity of DNA were first reported in 1980.(18) Other labs 19 21" subsequently reported similar results, although their anisotropy formulas were not entirely correct, and they did not so rigorously test the predicted decay function or attempt to fit likely alternatives. The development of new instrumentation, new data analysis techniques, and new theory and their application to different DNAs in various circumstances have continued to advance this field up to the present time. 

Methods based on the inhibitory effect of the analyte and the use of an enzyme thermistor have primarily been applied to environmental samples and typically involve measuring the inhibitory effect of a pollutant on an enzyme or on the metabolism of appropriate cells [162]. The inhibiting effect of urease was used to develop methods for the determination of heavy metals such as Hg(II), Cu(II) and Ag(I) by use of the enzyme immobilized on CPG. For this purpose, the response obtained for a 0.5-mL standard pulse of urea in phosphate buffer at a flow-rate of 1 mL/min was recorded, after which 0.5 mL of sample was injected. A new 0.5-mL pulse of urea was injected 30 s after the sample pulse (accurate timing was essential) and the response compared with that of the non-inhibited peak. After a sample was run, the initial response could be restored by washing the column with 0.1-0.3 M Nal plus 50 mM EDTA for 3 min. Under these conditions, 50% inhibition (half the initial response) was obtained for a 0.5-mL pulse of 0.04-0.05 mM Hg(II) or Ag(I), or 0.3 mM Cu(II). In some cases, the enzyme was inhibited irreversibly. In this situation, a reversible enzyme immobilization technique... 

For large-scale operations dichromate oxidation procedures provide precision. Microdistillation and careful temperature and acidity control make dichromate oxidation procedures rapid, accurate, time saving, and well-adapted to a multi-scale operation and automation (27, 28). 

The repetition time tr of the pulse sequence is independent of 7j, which may be different for nonequivalent nuclei. The optimum repetition time has been found to be t, = 4 r [22]. DEFT NMR requires careful adjustment of pulse widths for 90° and 180° pulses and (computer-controlled) pulse programming for accurate timing between pulses and pulse sequences. Other methods for improving signal noise using other pulse sequences and spin echo trains have been described [22, 25]. DEFT NMR, however, appears to be the most efficient method so far, as long as Tj and T2 are of the same order of magnitude. 

During the deposition of biophosphates a selective fractionation of chemical elements occurs. Although this process has been known in principle for some time380, 381, detailed studies had to await the development of new analytical tools such as the electron microprobe382. In order to relate the enrichment or depletion of elements in the course of biomineralization with time, precise time markes are needed380, 383 389). So the problem of elemental fractionation becomes a twofold one, i.e. quantitative measurements a few micrometer apart and accurate timing at about hourly intervals. 

Procedure - Equilibrate the Standard Preparation and the Assay Preparation in the dark at 80° for 2.5 hours, accurately timed. Cool, and introduce equal volumes (5 to 10 1) of the heat-equilibrated Standard Preparation and Assay Preparation into the high-pressure liquid chromatograph (See chromatography <621>) by means of a suitable sampling valve. Measure the peak responses obtained for the Assay Preparation and the Standard Preparation, and calculate the quantity, in mg, of C27H44O in the portion of Cholecalciferol taken by the formula 0.25C(Ay/Ae)> in which C is the concentration, in g per ml, of USP Cholecalciferol RS in the Standard Preparation, and Ay and As are the peak responses for cholecalciferol obtained for the Assay Preparation and the Standard Preparation, respectively. 

Duplicate Therapy Module Accurate, timely alerts to potential duplications of drug therapy, drug ingredients, and prescription refills. 

Errors in timing. For the determination of elements yielding short half-life indicator radionuclides (such as in the determination of oxygen via 7.3 sec16N), accurate timing is extremely important. For these cases electronic scaler timers are to be preferred over electromechanical types of timers. Errors due to variable detector dead-time must also be considered when the gross activities of the sample and the standard differ appreciably and the indicator radionuclide is short-lived. 

However, most modem highly accurate time-of-flight (TOF), Fourier-transform ion cyclotron resonance (FT-ICR) and Orbitrap mass analysers [107] have not been reported for TA analysis so far and are thus not discussed in this chapter. 

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