Null result

Tj /(1 — /32), /3 = v/c. The well known null result of the experiment confirmed that electromagnetic radiation does not obey galilean transformation theory. 

If a null result ensues, subsequent replication of the experiment is one way to feel more confident that the results are reliable. Alternatively, the animals may be trained in a conditioned odour preference task as described below. This would enable the investigator to further understand why the subjects did not respond in the habituation-dishabituation task. Videotaping the results should also become standard practice. As well as creating a permanent record that enables behavioural... 

Note that the c-operation in (4.4) (or (4.6)) yields a null result, because an electron can not be destroyed (created), where the fc-state is already empty (occupied). In the above equations,... 

In the Montreal case-control study carried out by Siemiatycki (1991) (see monograph on dichloromethane in this volume), the investigators estimated the associations between 293 workplace substances and several types of cancer. Isocyanates were one of the substances, and it was stated that the most common form in this study was toluene diisocyanates. The main occupations to which isocyanate exposure was attributed in this study were motor vehicle refinishers, motor vehicle mechanics and foundry workers. Only 0.8% of the study subjects had ever been exposed to isocyanates. For most types of cancer examined (oesophagus, stomach, colon, rectum, pancreas, prostate, bladder, kidney, skin melanoma, lymphoma), there was no indication of an excess risk due to isocyanates. For lung cancer, in the population subgroup of French Canadians (the majority ethnic group in this region), based on 10 cases exposed at any level, the odds ratio was 2.2 (90% CI, 0.9-5.3). [The interpretation of the null results has to take into account the small numbers and presumably low exposure levels. Workers had multiple exposures.]... 

One way to understand special relativity is to see how time dilation and Lorentz contraction of objects parallel to motion can be used to explain the null results of the Michelson-Morley [1] experiment, which was performed to measure the velocity of earth in relation to an assumed ether. The result was that the expected influence of such an ether on the velocity of light was not found. Let us now study this double-pass example, where one arm of a Michelson interferometer was perpendicular to the velocity of the earth s surface, while the other... 

Michelson and Morley [50] used an interferometer to measure the speed of light along two orthogonal directions parallel and perpendicular to the earth s orbital speed. They found that the speeds differed by a value somewhere in the range between 5 and 7.5 km/s. Michelson and Morley were extremely surprised because they expected to observe a difference of 30 km/s. At that time they had no plausible explanation for their empirical observation and decided to interpret the outcome of the experiment as a null result no difference in speed along both direction (apparently, the reason for this choice was that Fresnel s theory predicted no difference). 

Perhaps the alternative pathway to Ins(l,3,4,5)P4 in the yeast Ins(l,4,5)P3 3-/6-kinase null results from low levels of activity of other enzymes towards various Ins or Ptdlns phosphate substrates found in yeast, in a parallel to the results of Acharya et al. (1998) concerning the Drosophila IPP null. For example, perhaps the accumulation of Ins( 1,3,4,5)P4 results from phospholipase C action on PtdIns(3,4,5)P3. While no such phospholipase C activity has been documented in any organism, this hypothesis provides a way to discuss a... 

We cannot directly evaluate Eq. (54) because it contains delta functions. Evaluation of this expression for a finite system like a protein leads to a null result. To circumvent this problem, we thaw the delta function 8(x) as... 

To perform unbiased analyses, a collaboration-wide policy of blindness was established, where cut selections are optimized on a fraction of data or on time-scrambled data set. We present upper confidence limits for null results following the treatment described in (Feldman and Cousins, 1998) and incorporate systematic uncertainties into the calculation of confidence intervals according to (Conrad et al., 2003). The contributions to systematic uncertainties is predominantly due to variations of the optical properties of the ice, the absolute sensitivity of the OM, the neutrino cross section and the muon propagation. The combined systematic uncertainty is typically 30%, although the value varies slightly with the analysis method. 

It is interesting to note that, if the drift term is null (i.e. particles are not growing in size) and if there is no introduction of new particles into the system (i.e. the nucleation rate is null ), the right-hand side of Eq. (2.23) is null, resulting in a continuity equation for the particle phase of the form... 

Detector quality control records are reviewed to assure that control samples and the radiation background have been measured recently and that the detectors in use are within control limits (Section 11.2.10). Brief control source and background measurements are performed before the screening process begins to assure that detectors continue to operate appropriately and have not been contaminated recently. The detection limit in terms of activity per sample is calculated for all radionuclides of interest to determine whether a null result will meet radionuclide detection requirements for the submitted samples. 

The scenario, at first glance, seems to escape the standard experimental approach, namely comparison of the outcome from a set of observations with predictions based on a fittable model The control of all degrees of freedom of a quantum object is hard to achieve. Moreover, any measurement requires the interaction of quantum object and classical meter, and the object is supposed to suffer intolerable back action. However, there is a loophole based on "indirect null-result" measurements [10]. Fortunately enough, there are predictions, stated more than half a century ago, that may be matched with the results of measurements on a well-isolated and available type of microphysical system. A very counterintuitive prediction proclaims The evolution of a measured quantum system becomes slowed down, or, in the extreme, even completely frustrated [11,12]. This prediction, the "quantum Zeno effect" (QZE) [13], has evoked a wealth of theoretical work [14] but very little, and highly controversial experimental evidence. 

The obstruction of the ion s evolution was said comprehensible, at least in principle, in terms of physical reaction of the apparatus on the ion ensemble, and as such not being too surprising. Only the non-local correlation of system and meter, and a null result of the detection, however, would exclude dynamical coupling and qualify as back-action-free measurement. Such a procedure would prove the obstruction of the evolution by measurement, that is, by gain of information, and would establish a real QZE, or "quantum Zeno paradox" (QZP) [21]. 

This null result does not simply mean that the error of the Simpson rule formula is zero, but rather the integration of the third term is zero. We need to go to the fourth term of the approximate polynomial, which is... 

It was proposed independently by Hendrik Lorentz (1853-1928) and George Fitzgerald (1851-1901) in 1892 to account for the null result of the Michelson-Morley experiment. The contraction was given a theoretical background in Einstein s special theory of relativity. In this theory, an object of length lo at rest in one frame of reference will appear, to an observer in another frame moving with relative velocity v with respect to the first, to have length Ua-i /a,... 

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