ABSTRACT
Sferics are low frequency, low intensity electromagnetic pulses radiating from distant meteorological events and other yet unknown sources. It has been hypothesized that sferics are part of the purported sensitivity to weather changes reported by headache sufferers. We tested this proposal. Patients (migraine and/or tension headache) enrolled in a randomized clinical trial gave daily headache data (intensity, frequency, duration of headache) for at least 18 weeks. Concurrently, a sferics measurement station in the vicinity of the patients recorded frequency and intensity of sferics. Usable headache data from 21 patients and the corresponding sferics series were subjected to time series analysis applying ARIMA models and then cross-correlated. We found significant and consistent cross-correlations of moderate size at lag 0 in one patient between ARIMA-filtered headache intensity and frequency (r = 0.18) and amplitude of sferics (r = 0.20). We conclude that in an unselected sample of headache patients some may indeed be susceptible to the low intensity type of electromagnetic radiation exemplified by sferics pulses. This phenomenon warrants further scrutiny.
Subject(s)
Headache/etiology , Meteorological Concepts , Radiation , Confidence Intervals , Humans , Migraine Disorders/etiology , Prospective Studies , Tension-Type Headache/etiologyABSTRACT
A new method of making precision alignment of rectilinear systems of any length without requiring high resolution optics is described. Laser light with antisymmetrical transverse phase is used to produce intensity asymmetries by means of diffraction behind a misaligned target. The apparatus is very simple but flexible enough to attain alignment of extreme accuracy within an operational range from zero to several kilometers. Under favorable conditions, misalignments of less than 0.01 mm are detectable (10(-8) rad at a distance of 1 km). Both visual and automated detection is possible in one as well as in two directions. The advantages of the asymmetry method are discussed with respect to conventional and existing laser techniques; applications and limitations are cited.
