The purpose of this study was to reproduce and extend an earlier investigation of the effects of human exposure to combined, 60-Hz electric and magnetic fields. This paper presents the neurobehavioral results. Thirty men participated in one training session and four testing sessions. Subjects were randomly assigned to two groups. The 18 subjects in Group I were exposed (9 kV/m, 20 microT) and sham exposed in two counterbalanced orders. In Group II, half of 12 subjects were exposed (9 kV/m, 20 microT) every session, and the remaining half were sham exposed every session. The study was doubly blinded. Measures of cardiac interbeat interval, event-related brain potentials, and performance were obtained before, during, and after exposures. As in the earlier study, exposure to the combined field resulted in a statistically significant slowing of heart rate, in changes in late components of event-related brain potentials, and in decreased errors on a choice reaction-time task. In addition, field effects on several other measures approached statistical significance. The physiological measures obtained during exposure indicated that effects were greatest soon after the field was switched on, and again when it was switched off. The data indicate that changes in exposure level may be more important than duration of exposure for producing effects in human beings.
This human exposure study examined the relationship between field strength and biological response and tested whether the exposure levels at which the greatest effects occur differ for different endpoints. Three matched groups of 18 men each participated in two 6 h exposure test sessions. All subjects were sham exposed in one session. In the other session, each group of subjects was exposed at a different level of combined electric and magnetic field strength (low group:6 kV/m, 10 microT; medium group:9 kV/m, 20 microT; and high group: 12 kV/m, 30 microT). The study was performed double blind, with exposure order counterbalanced. Significant slowing of heart rate, as well as alternations in the latency and amplitude of event-related brain potential measures derived from the electro encephalogram (EEG), occurred in the group exposed to the 9 kV/m, 20 microT combined field (medium group). Exposure at the other field strength levels had no influence on cardiac measures and differential effects on EEG activity. Significant decrements in reaction time and in performance accuracy on a time estimation task were observed only in the low group. These results provide support for the hypothesis that humans may be more responsive to some combinations or levels of field strength than to others and that such differences in responsivity may depend, in part, on the endpoint of interest.
Loading of bioavailable phosphorus, traditionally measured as soluble reactive phosphorus (SRP), contributes to the eutrophication of aquatic ecosystems. However, polyphosphates are also bioavailable but escape detection by the standard method used for measuring SRP. 31P nuclear magnetic resonance spectrometric analysis of sediment extracts and enzymatic assay of surface waters reveal heretofore unreported presence of pyrophosphate (Ppi) in coastal wetlands. We show that the accumulation of Ppi (the smallest chemical form of polyphosphate) in coastal wetlands is related to human impact and can occur in quantities that exceed that of SRP. We further demonstrate that Ppi is readily utilized by microbes in coastal wetland sediments in the presence of nitrogen and carbon and can serve as a reservoir of orthophosphate. Thus, Ppi accumulation in estuaries will subsidize the in situ biogeochemical phosphorus cycle. This has important ecological implications for trophic responses and estuarine productivity.
The effects of stress on the affective content of dreams and on rapid‐eye‐movement (REM) period eye‐movement activity and respiration were studied. The experiment was also designed to examine the similarity between walking and sleeping states in the respiratory correlates of emotion. Sleep records and dream reports were collected following the viewing of stress and neutral films. The stress films significantly increased dream anxiety and also increased REM‐period respiratory irregularity among those Ss who, in the walking state, showed irregular breath patterns in response to stressful film scenes. Some evidence was also found that dream affect is related to RFM‐period respiratory irregularity among the Ss who are walking responders. These data are interpreted as supporting the hypothesized congruence between the waking und dream states in The relationship between affect and breathing irregularity.
Left and right parietal EEGs were recorded while seven subjects experienced sexual climax through self-stimulation. EEG data were quantified by continuous cumulated measurements of the integrated areas of EEG recording during successive 1-sec epochs. In eight out of 12 experiments, this measure revealed a statistically significant change in laterality. Controlled replications with two of the original subjects obviated the possibility that two potential sources of artifact (hand used for masturbation and gross body movements) accounted for the changes. While previous research has focused on vasomotor and myotonic indices of sexual response, this study demonstrates the significance of brain phenomena in sexual orgasm.
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