Spurious Causes Research Articles

Experimental study of thermoelectricity in superconducting indium

This paper reports on a comprehensive study of thermoelectricity in pure superconducting indium near the transition temperature. The samples consisted of hollow bimetallic toroids of lead and indium. Upon application of a temperature gradient, a magnetic flux was produced within the hollow cavity of the toroids which could be coupled, via a superconducting flux transformer, into a superconducting quantum interference device magnetometer. The thermoelectric origins of the magnetic flux and the experimental method are discussed in detail. The magnetic flux was measured in seven specimens, and in each was found to diverge as the transition temperature was approached with a ${(1\ensuremath{-}\frac{T}{{T}_{c}})}^{\ensuremath{-}\frac{3}{2}}$ power-law dependence. The magnitude of the flux varied by about a factor of 40 among the different samples and appeared to scale with the normal-state thermoelectric properties of the indium. Tests intended to eliminate possible spurious causes for the magnetic flux are also discussed.

Increase in Cancer of the Corpus Uteri in the San Francisco-Oakland Standard Metropolitan Statistical Area, 1960–75<xref ref-type="fn" rid="FN1">2</xref>

A significant rise in the incidence of carcinoma of the corpus uteri in women of the San Francisco-Oakland standard metropolitan statistical area (SMSA) was reported by the Resource for Cancer Epidemiology. The incidence among white females increased by over 50% in the 6 years between 1969 and 1975. The increase was limited to the groups over 50 years old and to invasive cancers of the endometrial lining. The increase occurred in all five of the SMSA counties and, in white women in Aalmeda County, the average annual incidence for the 50- to 74-year age group tripled in 15 years. The rise was greatest in the areas of most affluence. Possible spurious causes of increase, such as changing diagnostic criteria, better case finding, or better reporting were examined and ruled out. The data suggested that the increase was due to the recent introduction of a potent endometrial carcinogen to the population group affected.

Ultrasound in the Investigation of Gallbladder Disease

CONVENTIONAL oral cholecystography with iopanoic acid has reached a high degree of diagnostic accuracy and is currently the standard mode of evaluation of gallbladder disease. 1 However, it is of limited applicability in several situations: The acutely ill patient. The study, when using iopanoic acid may take 14 to 48 hours to complete. The patient who cannot ingest pills. Patients who, because of symptoms or therapy, cannot ingest or retain iopanoic acid or who are undergoing gastric suction must be examined by alternate means. The patient with jaundice and liver function abnormalities. Although nonvisualization of the gallbladder in most cases is highly specific for gallbladder disease, 1 the presence of jaundice or abnormal results from liver function studies is a spurious or nonbiliary cause for nonvisualization and does not necessarily indicate a pathological gallbladder condition. The patient with a nonbiliary cause for nonvisualization. Nonbiliary causes that may

The reorientation of Cd 2+-vacancy and Pb 2+-vacancy complexes in KCl

The relaxation of Pb 2+-vacancy and Cd 2+-vacancy dipoles in purified KCl crystals was studied using a double crystal dc polarization method which self-corrects relaxation effects due to spurious causes. In the radius range from Cd 2+ to Ba 2+ these results and most others support Dreyfus' model. The reciprocal relaxation times for each impurity are given by τ −1 Cd =2.06x10 12 exp(−s0.64±0.01 eV) kT ; τ −1 Pb =1.19x10 13 exp(−0.69±0.01 eV) kT . It is also shown that the presence of H 2O or its products greatly perturb the relaxation times observed.