Analog experiments apparatus

Direct repressors interact with the basal components of the transcription apparatus or with transcriptional activators to inhibit their activity. Specific repressors, analogous to transcriptional activators, are constructed modularly, with a DNA-binding domain and a repressor domain. The repressive character of such domains has been proven in domain swapping experiments. The mechanism of specific repression remains speculative. The following mechanisms are, however, conceivable ... 

In the current apparatus, the TOF signal was displayed on a 400-MHz analog oscilloscope. The waveform from the screen was coupled into an IBM personal computer for data analysis and storage. In general, TOF experiments are carried out under single-shot measurements, which means that the single-event bandwidth of the oscilloscope must be much larger than l/t-p. 

Up to now, we have given a general theoretical development of the self-beat technique. As a practical illustration of the experimental apparatus used to detect autocorrelation functions in scattering experiments, the equipment currently used in our laboratory will now be described. While our treatment of the autocorrelation function has been in terms of an analog signal, the computer that measures this function is actually a digital device. This is based on the fact that it is also valid to count the scattered photons in order to calculate Ci(r) as the optical intensity signal is essentially determined by the number of photons that strike the photocathode per unit time. We have then... 

But the "jury member" analogy fails to capture a vital component of evaluation the report is directed toward highly trained participants in laboratory research. Even if the reader never performed the experiment described in the report, the reader typically appeals to direct participation in experiments that are similar to those described. At least privately, the reader rehearses the kind of malfunctions of apparatus, mistakes of implementation, and interfering effects that plagued past experiments. Are such dangers relevant to the present experiment If so, are they avoidable The answers to these questions require a command of the subject matter that is usually reserved for expert witnesses. The metaphor of "reader as jury member" fails to capture such a requirement of the reader. In the context of the legal system in the United States, jury members are rarely trained in the topics examined by expert witnesses. So, because a virtual witness is usually well versed in the techniques of laboratory research, the... 

Besides the pressure drop inside the columns there can be an additional pressure loss due to the piping and the valves between the columns. In experiments, a large pressure drop was found in an SMB-SFC apparatus due to these flow resistances [55]. Taking into account the pressure drop as a function of mass flow rates, a pressure-loss coefficient f for the total flow resistance (analogous to pipeline construction) between two columns is determined by fitting to experimental pressure drops. Then the pressure drop can be calculated from ... 

Two years elapsed before better and stronger equipment was available for further experimentation. When ethylene was heated to 180 °C in this new equipment, the pressure in the apparatus dropped unexpectedly, so more ethylene was pumped in. Then, when the reaction vessel was opened, the I.C.I. chemists found a large amount of white powdery solid, which was the long-sought polyethylene. Because they knew that the polymerization could not account for all of the pressure drop that had been observed, they suspected a leak in one of the joints of the apparatus. This idea led to the proposal that the polymerization had been catalyzed by oxygen in the air that had leaked into the apparatus, and this hypothesis was confirmed by experiments in which air was intentionally included with the ethylene. Oxygen can act as a radical initiator and catalyze the polymerization by a chain-reaction mechanism analogous to Equations 22.7-22.10. 

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