Comparing tiltmeters for crustal deformation measurement--a preliminary report

A collection of high-precision tiltmeters is being operated at Pinon Flat Observatory, southern California, both to compare instruments and to measure tectonic deformation. We report on 1.2 years of data from four of these: two Michelson-Gale long fluid tiltmeters, one long center-pressure tiltmeter, and a shallow borehole tiltmeter. The three long-base instruments are all located on the same baseline, with a precise leveling line running between their end-monuments. At nontidal frequencies, only the two Michelson-Gale instruments show some coherence (gamma 2 = .3 for periods of 2 to 4 days), while the center-pressure instrument is correlated with air temperature at periods from a few days to a few weeks. The most stable tilt record shows a secular rate of 0.28 mu rad/a, which may be real. Over much longer times, leveling to specially stabilized bench-marks should confirm this. Comparing instruments has identified more and less successful measurement techniques; it appears that low-noise data will most probably be produced only by relatively complex and expensive instruments, though even for these, the operating costs over any reasonable lifetime will exceed the capital cost. Even the best existing sensors must be improved to measure continuous tectonic motions.

What is a pain center?

The authors present the concept that a multi-disciplinary interdepartmental pain center should include: 1) an initial out-patient pain clinic, 2) an inpatient pain service for diagnosis of pain problems and treatment of patients with intractable pain, including pain from cancer, 3) a psychotherapeutically-oriented chronic benign Pain Unit, 4) facilities for clinical and basic pain research, and 5) affiliations for an adequate teaching program.

Words of chronic pain

An analysis of the language of pain complaints, employing categories of descriptors, was used to determine if chronic pain of either psychiatric of organic origin might be depicted in terms specific for the disease. The complaints of 128 patients with chronic pain were studied for characteristic patterns. Patients with pain of organic etiology used sensory-thermal (e.g., hot, burning) words more frequently than those with pain of psychiatric origin. Female patients with pain attributed to anxiety used sensor-temporal words (e.g., throbbing) more frequently than those with other psychiatric diagnoses. There was also a statistically significant preponderance of pain on the left when the groups of patients with physical and psychological illness were combined.

A brief trial of phenytoin therapy for thalamic pain

Phenytoin was given in full dosage to eight patients with thalamic pain and two others with intractable pain resistant to other forms of treatment. Serum levels were monitored and correlated with dosage levels. Three patients improved markedly, two improved only minimally, two were unchanged, and three were worse. Those patients who had improved noted return of original pain on stopping phenytoin. The results indicate the need for a further study of the drug in thalamic and other chronic pain states.