Short-term fluctuations

Second, there are considerable short-term fluctuations in material prices. Copper dropped 15% in the month of September 1993 gold, in the same period, rose 38%. Aluminium changed in price by nearly 10% in a single day in December 1993. These are large changes, important to the purchaser of materials. 

Electric utilities can anticipate peak demands and be prepared to meet them. On the other hand, there arc short-term fluctuations in the power levels that a utility cannot anticipate but must handle quickly. Superconducting magnetic energy storage (SMES) is a technology that has potential for meeting both anticipated peak demands and those requiring quick response. 

The values of raw materials and products can be found in trade journals such as Chemical Marketing Reporter (published by Schnell Publishing Company), European Chemical News and Asian Chemical News (published by Reed Business Information). However, the values reported in such sources will be subject to short-term fluctuations, and long-term forecasts will be required for investment analysis. 

Equation (64) justifies the application of flux-balance analysis even in the face of (i) fast short-term fluctuations and (ii) periodic long term for example, circadian variability. The steady state balance condition restricts the feasible steady-state flux distributions to the flux cone P = v° G IRr IVv0 = 0. The reduction of the admissible flux space, with some of its algebraic properties already summarized in Section III.B, is exploited by several computational approaches, most notably Flux Balance Analysis (FBA) [61, 71, 235] and elementary flux modes (EFMs) [96, 236 238],... 

In a recent study involving the inorganic analysis of human ribs from 10 subjects,66 it has been found that the calcium content varied from 24.12 to 26.91 per cent, the phosphorus from 10.75 to 12.11 per cent, and the carbonate as carbon dioxide varied from 2.81 to 3.95 per cent. Inter-individual differences of this magnitude would seem to exist since the inorganic composition of bone is probably relatively stable and not subject to short-term fluctuations. 

Sect. 3.8). Short-term fluctuations in the isotope composition of sea water must arise during glacial periods. If aU the present ice sheets in the world were melted, the 8 0-value of the ocean would be lowered by about l%o. By contrast, Fairbanks (1989) has calculated an 0-enrichment of 1.25%c for ocean water during the last maximum glaciation. 

It is also possible to use an internal standard to correct for sample transport effects, instrumental drift and short-term noise, if a simultaneous multi-element detector is used. Simultaneous detection is necessary because the analyte and internal standard signals must be in-phase for effective correction. If a sequential instrument is used there will be a time lag between acquisition of the analyte signal and the internal standard signal, during which time short-term fluctuations in the signals will render the correction inaccurate, and could even lead to a degradation in precision. The element used as the internal standard should have similar chemical behaviour as the analyte of interest and the emission line should have similar excitation energy and should be the same species, i.e. ion or atom line, as the analyte emission line. 

Stoodley, P., Z. Lewandowski, J. D. Boyle, and H. M. Lappin-Scott. 1999c. Structural deformation of bacterial biofilms caused by short-term fluctuations in fluid shear An in situ investigation of biofilm rheology. Biotechnology and Bioengineering 65 83—92. 

Weight regulation is normally a very precise process. Ignoring short-term fluctuations (which are mostly gain and loss of water), body weight stays remarkably constant. Weight regulation... 

Schutz et al. (223) concluded from a study of the seasonal and latitudinal variations of n(N20), as well as from its short-term fluctuations, that its lifetime may be 10 yr or less. This would require a much more efficient sink than is currently known. 

The naturally occurring radioisotopes that were measured, Be and Pb, continue to be detected in most air filter samples. Variations in the annual mean concentrations of Be at many of the sites appear to result primarily from changes in the atmospheric production rate of this cosmogenic radionuclide. Short-term variations in the concentrations of Be and °Pb continued to be observed at many sites at which weekly air filter samples were analyzed. These short-term fluctuations probably resulted from variations in meteorological factors. The data from quality control samples indicate that in general the reliability of the air filter measurements are acceptable for their intended application. 

Figure 6.1 Example chromatogram illustrating noise (short-term fluctuations, approximate peak-to-peak value shown by lines on expanded section) and drift (the slope in the baseline, indicated by the arrow). The signal-to-noise ratio for the first three peaks should be sufficient for reasonably adequate quantitation, but the broader fourth peak on the noisy, sloping baseline would pose problems for most integrators.

Double-beam instruments offer the advantage that they compensate for all but the most short-term fluctuations in the radiant output of the source. They also compensate for wide variations of source intensity with wavelength. Furthermore, the double-beam design is well suited for continuous recording of absorption spectra. 

Other advantages that accrue for biofilms on surfaces include protection from short-term fluctuations in pH, salt and biocide concentrations, and dehydration. Because of the mass-transfer resistance of the biofilm to the transport of nutrient, conditions will change throughout the biofilm depth. Where several... 

To obtain good estimates of nutrient fluxes, it is important to determine accurately the variation in its concentration over a tide. Therefore a sufficient number of samples should be taken to reflect the temporal variability. It should be noted that the concentration of particulate material is prone to greater short-term fluctuations than dissolved constituents and so the former requires more intensive sampling than the latter. In addition to temporal variability, spatial variability needs also to... 

Let i/(t) be the total execution time of a Web Service (including the round trip time of the communication) measured at the current time t, or another varying parameter of Web Services that we use for selection. A monitor logs the values y To), y To + S), y TQ + 2d), etc., where tq is the first measured value and 6 is an elementary time slot, which is always equal to one in case of a logical clock. Subsequently, envelopes for the measured values (e.g. maximum execution time envelopes) are computed for the last M blocks of duration T6. They describe the dynamics from short-term fluctuations (Wi) to long-term trends flYr) where i = 1... M and k = 1... T ... 

M32. Mortensen, H. B., Steady levels of hemoglobin Ajc concentration during short-term fluctuations in blood glucose. Sci. Tools 27, 21-22 (1980). 

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