Illusory Decoherence

If a quantum experiment includes random processes, then the results of repeated measurements can appear consistent with irreversible decoherence even if the system's evolution prior to measurement was reversible and unitary. Two thought experiments are constructed as examples.Comment: 10 pages, 3 figure

Microcomputer-based system for 24-hour recording of oesophageal motility and pH profile with automated analysis

A system developed for long-term simultaneous recording of oesophageal motility and pH in the ambulant patient is described. The system consists of a microprocessor based data-acquisition and preprocessing device, a personal computer for postprocessing, report generation and data storage, a miniature two-sensor pressure catheter and a pH electrode. Identification and classification of oesophageal contractions are performed in separate steps, using online preprocessing software for identification and offline postprocessing software for categorisation, classification and report generation. Contractions are categorised as peristaltic, simultaneous or nontransmitte and classified according to their amplitude, duration and propagation velocity. The method described reduces the amount of data from 870 kbyte to approximately 40 kbyte per 24 hours in a multiparameter recording device, and offers the opportunity for offline postprocessing with different sets of criteria. The system has been found to be accurate and reliable in 24-hour studies in both healthy volunteers and patients with non-cardiac chest pai

Physiological gastroesophageal reflux and esophageal motor activity studied with a new system for 24-hour recording and automated analysis

Gastroesophageal reflux and esophageal motility were studied for 24 hr in 32 ambulatory healthy volunteers (20-73 years old), using a newly developed system, consisting of a microprocessor-based data recorder and algorithms for fully automated data analysis. Physiological reflux was more extensive than expected on the basis of widely used normal values. The percentage of time with pH less than 4 and the duration of the reflux episodes increased with age. Of the more than 2000 esophageal contractions occurring per day, peristaltic contractions constituted 50.9 +/- 2.0%. Their amplitude was significantly lower between meals than during meals and during the night. The duration of the peristaltic contractions increased with age. Simultaneous contractions constituted 10.4 +/- 1.2% of the esophageal contractions. Their incidence increased with age. We conclude that continuous ambulatory 24-hr recording with automated analysis of esophageal motility and pH profile is feasible, that the upper limits of normal in ambulatory esophageal pH recording are higher than previously accepted, and that age, meals, and body position must be taken into account in the interpretation of both 24-hr esophageal pH and pressure dat