Spike surveys

The local authority determined tiiat (referring to CIRIA guidance), positive gas results encountered during a spike survey are generally... 

From this survey it is clear that just as normal neuronal function requires appropriately balanced inhibitory and excitatory controls so the generation of interictal spikes depends on disturbances in both. Clearly activity cannot spread without the activation of excitatory circuits, in which NMDA receptors play an important role, but it will be much facilitated by reduced inhibition (Masukawa et al. 1989). These observations may help to explain the establishment of a focus and the development of the interictal spike, but why activity can only spread to seizure proportions, at certain times, is less clear. It will, however, again require overactivity of excitatory circuits inadequately controlled by inhibitory processes. Since these controls are mediated by... 

The report (5) on the study recommended that a less active charcoal be tested. A literature survey did not yield any conclusive evidence for successful collection by recovery from alternative sorbents. On the basis of the little information available, we selected petroleum charcoal and three porous polymers to test (petroleum charcoal is less active than coconut charcoal). All the porous polymers were based on aromatic monomers, and they should be good collectors for nonpolar aromatics. Aliquots of 113 pg diphenyl were spiked onto these sorbents, and the samples were desorbed with various solvents. The results are given below. 

A literature survey shows that the concentration of the analyte found when analyzing a spiked blank sample matrix is often expressed as the percentage of the known or true drug concentration and is called recovery. By this definition, recovery is the same as accuracy, which is why accuracy is reported as recovery in many scientific reports. The difference is that the recovery, as defined, should be close to 100%, while the accuracy close to 0%. 

Today other substances can be used and they are now referred to as date-rape drugs and there is widespread belief that this type of crime is quite common. It isn t. Clinical analysis of the urine or blood of women who claim to have fallen victim to their use, shows that very few have in fact been deliberately drugged. Most have passed out unconscious because they have drunk too much alcohol. In 2005, Michael Scott-Ham and Fiona Burton of the Forensic Science Service, London, reported in the Journal of Clinical Forensic Medicine the results of a 3-year study. They analysed 1014 cases of alleged date rape but found that only 21 of the victims (2%) had had their drink deliberately spiked. On this basis, of the 500 such cases reported annually in the UK, only 10 are actual date rapes. In the USA there are more than 250,000 reported rapes per year, but how many of these are drug assisted is not known, although on a comparable basis of 2% it would mean around 5,000. What was discovered in the UK survey was that while alcohol had caused most of the... 

Perlee, H. E., and Christos, T., Summary of Literature Survey of Hypergolic Ignition Spike Phenomena, Phase I Final Report, United States Department of the Interior Bureau of Mines, Pittsburgh, Pennsylvania, April 8 to December 31, 1965. 

The 1918 map shows several paths that go to the Dalecarlia property— one goes northwest from the American University and is a straight line that enters the federal property near the railroad bed described and found in our AOI 2 report. Spikes have been found where this path enters the federal property in addition to the spikes found near the Rick Woods pit location where a rail bed is still evident. The 1994 geophysical survey found a line of shells along what is believed to be the route of the narrow-gauge railway based on the railroad spike recoveries. Perhaps these shells simply fell off the railcar and were not fired into the area. 

Spad A flat spike hammered into a wooden plug anchored in a hole drilled into the mine ceiling from which is threaded a plnmbline. The spad is an underground survey station similar to the use of stakes in marking snrvey points on the surface. A pointer spad, or sight spad, is a station that allows a mine foreman to visually align entries or breaks from the main spad. 

For the quantitative study, 30 young men aged 18-35 (mean 26 years) were recruited, all being heavy users of hair wax. Overall, a good brand distribution was strived for users of Swiss 0 Par, got2b, L Ordal and private label brands (e.g. REWE, Rossmann). Each respondent evaluated one AXE product over a longer period of time AXE Spiked Up in = 16) and AXE Smart Look (n = 13). Out of the 30 respondents, there was one drop-out, who could not be motivated to carry on with the survey. Fieldwork took place in April 2013. Each participant evaluated one test product at six different contact points during one day, and answered various questions on their mobile phone. 

Figure 8.11 Graphical representations of the definition and implications of the EPA definition of an MDL. (a). Assumed normal frequency distribution of measured concentrations of MDL test samples spiked at one to five times the expected MDL concentration, showing the standard deviation s. (b) Assumed standard deviation as a function of analyte concentration, with a region of constant standard deviation at low concentrations, (c) The frequency distribution of the low concentration spike measurements is assumed to be the same as that for replicate blank measurements (analyte not present), (d) The MDL is set at a concentration to provide a false positive rate of no more than 1% (t = Student s t value at the 99 % confidence level), (e) Probability of a false negative when a sample contains the analyte at the EPA MDL concentration. Reproduced with permission from New Reporting Procedures Based on Long-Term Method Detection Levels and Some Considerations for Interpretations of Water-Quality Data Provided by the US Geological Survey NationalWater Quality Laboratory (1999), Open-File Report 99-193.

The development of sensitive analytical methods had been an indispensible tool in advancing research in aflatoxins, whether the research need was for survey of agricultural crops, transmission of residues from feed to food, following the course of detoxification, preparation of spiked meals for experimental use, or for toxicologic and metabolic studies. Methods had to be developed as the... 

Another area of concern is the occurrence of spontaneous noise spikes and the presence of man made and natural debris around the earth and in the solar system. Both phenomena could potentially affect the reliability of the survey since they are indistinguishable from astronomical infrared objects. For this reason there is considerable emphasis on repetition of the survey. In the survey instrument coincidence of source detections will be required. Moreover, scans in consecutive orbits will have a fifty percent overlap. 

When several rectifiers protect a structure, it is necessary that all rectifiers be interrupted at the exact same instant in order to obtain meaningful measurements. Pipeline operators usually specify that at least two rectifiers ahead of the survey team and two rectifiers behind the survey team have to be interrupted in a fully synchronized manner. The amount of time between current interruption and depolarization can vary from a fraction of a second to several seconds, depending upon details of the structure. In addition, capacitive spikes that occur shortly after current is interrupted may mask the instant-off potential. Measurements made with a recording voltmeter are preferred as they can be subsequently analyzed to determine the real instant-off potential [16]. 

Fig. 10.31 Portable reference electrode probe, (a) Surveys of electrode potential distribution on ships hulls, submerged offshore pipelines, oilrigs, platforms, jetties and docks are often carried out by manual diver-held probes, (b) These battery-powered devices usually incorporate a tip spike, a silver/silver chloride reference electrode and a digital voltmeter (dvm) within a tough, insulated and sealed pistol. The shroud surrounding the electrode element defines the sensing area. These probes are used to depths of approximately 300 m and are capable of measuring to a precision of 1 mV. Rechargeable Ni-Cd batteries are used. Sharpened tips may be used to penetrate coatings. (Courtesy Corrintec (UK) Ltd.)...

The LCR survey data was also assessed to see if there were any signs of galvanic corrosion at copper-lead service line joints, by reference to atypical spikes in the lead results. The total number of copper-lead cases from all the LCR surveys combined was 27. Of these, 14 (51.85%) had lead <5 pg/1, 7 (25.93%) had lead between 5 and 10 pg/1, 3 (11.11%) had lead between 10.1 and 15 pg/1, and 3(11.11%) had lead >15 pg/1. This profile, based on the 27 cases of copper-lead service lines, is fairly similar to the profile of all lead concentrations observed from all the LCR surveys, and it therefore appears that galvanic corrosion at the copper-lead service line joint is not a major issue. 

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