Spike-ins

Figure C3.3.12. The energy-transfer-probability-distribution function P(E, E ) (see figure C3.3.2 and figure C3.3.11) for two molecules, pyrazine and hexafluorobenzene, excited at 248 nm, arising from collisions with carbon dioxide molecules. Both collisions that leave the carbon dioxide bath molecule in its ground vibrationless state, OO O, and those that excite the 00 1 vibrational state (2349 cm ), have been included in computing this probability. The spikes in the distribution arise from excitation of the carbon dioxide bath 00 1 vibrational mode.

Spike recoveries for samples are used to detect systematic errors due to the sample matrix or the stability of the sample after its collection. Ideally, samples should be spiked in the field at a concentration between 1 and 10 times the expected concentration of the analyte or 5 to 50 times the method s detection limit, whichever is larger. If the recovery for a field spike is unacceptable, then a sample is spiked in the laboratory and analyzed immediately. If the recovery for the laboratory spike is acceptable, then the poor recovery for the field spike may be due to the sample s deterioration during storage. When the recovery for the laboratory spike also is unacceptable, the most probable cause is a matrix-dependent relationship between the analytical signal and the concentration of the analyte. In this case the samples should be analyzed by the method of standard additions. Typical limits for acceptable spike recoveries for the analysis of waters and wastewaters are shown in Table 15.1. ... 

If the spike recovery for Bsf is acceptable, or if the result for sample B is below the method s detection limit or outside the range of 0.1 to 10 times the amount of analyte spiked in Bsf, then the duplicate samples Ai and A2 are analyzed. The results for Ai and A2 are discarded if the difference between their values is excessive. If the difference between the results for Ai and A2 is within the accepted limits, then the results for samples Ai and B are compared. Since samples collected from the same sampling site at the same time should be identical in composition, the results are discarded if the difference between their values is unsatisfactory, and accepted if the difference is satisfactory. 

Fig. 6.7. The predicted, one-dimensional, mean-bulk temperatures versus location at various times are shown for a typical powder compact subjected to the same loading as in Fig. 6.5. It should be observed that the early, low pressure causes the largest increase in temperature due to the crush-up of the powder to densities approaching solid density. The "spike in the temperature shown on the profiles at the interfaces of the powder and copper is an artifact due to numerical instabilities (after Graham [87G03]).

Figure 11-14 shows the calculated hole density (upper panel) and the electric field (lower panel) as a function of position for the three structures. For the devices with a hole barrier there is a large accumulation of holes at the interface. The spike in the hole density at the interface causes a rapid change in the electric field at the interface. The field in the hole barrier layer is significantly larger than in the hole injection layer. For the 0.5 eV hole barrier structure, almost all of the... 

Spike-ins are usually RNA transcripts used to calibrate measurements in a DNA microarray experiment. Each spike-in is designed to hybridize with a specific control probe on the target array. Manufacturers of commercially available microarrays typically offer companion RNA spike-ins kits . Known amounts of RNA spike-ins are mixed with the experiment sample during preparation. Subsequently the measured degree of hybridization between the spike-ins and the control probes is used to normalize the hybridization measurements of the sample RNA. 

A seizure is accompanied by a burst of spikes in the EEG. Between these so-called iclal phases are solitary EEG interictal spikes. Each of them represents the field potential associated with a burst of action potentials in a group of neurons within the epileptic focus (Fig. 16.2). 

There are many studies on the induction and spread of spiking in animals both in vivo and in isolated brain slices, generally initiated by the use of GABA antagonists or removal of Mg + ions in vitro). Unfortunately since neither of these events is likely to occur in or around a human epileptic focus the results do not tell us much about how focal activity arises and spreads in humans. This needs to be achieved by the use of human epileptic tissue even though the procedures found to control experimentally induced spiking may well be applicable to humans. 

Zia-Gharib, F and Webster, RA (1991) Effects of compounds modulating amino acid transmission on the development and control of bicuculline-induced epileptogenic spiking in the rat. Neuropharmacology 30 995-1009. 

All fortified (spiked) matrix samples are prepared in the laboratory at the same concentration. Laboratory spikes are immediately put into cold storage. Trip and fleld spikes are kept cold and sent to the fleld. The trip spikes will accompany sample shipments. The fleld spikes are stored and transported in the same manner as the trip spikes. When practical, air should be pulled through fleld spikes in the same manner as actual fleld samples being taken at the time of the study. 

Here K is the kernel matrix determining the linear operator in the inversion, A is the resulting spectrum vector and Es is the input data. The matrix element of K for Laplace inversion is Ky = exp(—ti/xy) where t [ and t,- are the lists of the values for tD and decay time constant t, respectively. The inclusion of the last term a 11 A 2 penalizes extremely large spectral values and thus suppresses undesired spikes in the DDIF spectrum. 

In the USSR, permitting and banning pesticides took place without considering human or environmental interests. Fig. 1 illustrates this trend you can clearly see the spikes in pesticide banning in the USSR/Russia. 

In similar manner, spikes in the image from cosmic rays are extinguished by simple application of the median filter with a small submatrix size (3 or 5). 

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