On the categorization of uranium materials using low resolution gamma ray spectrometry.

In order to characterize uranium materials during e.g. nuclear safeguards inspections and in initial stages of nuclear forensic investigations, hand-held low resolution gamma ray detection instruments with automatic uranium categorization capabilities may be used. In this paper, simulated response curves for a number of matrices applied on NaI(Tl) scintillation detector spectra show that the result of the categorization is strongly dependent on the physical properties of the uranium material. Recommendations on how to minimize the possibility of misclassification are discussed.

Brain networks affected by synchronized sleep visualized by positron emission tomography.

Nineteen lightly sleep-deprived healthy volunteers were examined with H2(15)O and positron emission tomography (PET). Scanning was performed during wakefulness and after the subjects had fallen asleep. Sleep stage was graded retrospectively from electroencephalogram (EEG) recordings, and scans were divided into two groups: wakefulness or synchronized sleep. Global flow was quantified, revealing no difference between sleep and wakefulness. A pixel-by-pixel-blocked one-way analysis of variance (ANOVA) was performed after correcting for differences in anatomy and global flow. The sum of squares of the z-score distribution showed a highly significant (P < 0.00001) omnibus difference between sleep and wakefulness. The z-score images indicated decreased flow in the thalamus and the frontal and parietal association cortices and increased flow in the cerebellum during sleep. A principal component (PC) analysis was performed on data after correction for global flow and block effects, and a multivariate analysis of variance (MANOVA) on all PC scores revealed significant (P = 0.00004) differences between sleep and wakefulness. Principal component's 2 and 5 correlated to sleep and revealed distinct networks consisting of PC 2, cerebellum and frontal and parietal association cortices, and PC 5, thalamus.

Regional activation of human cerebral cortex upon an adaptation in mirror drawing.

To elucidate cerebral regions involved in adaptation to mirror drawing, changes in regional cerebral blood flow were measured using positron emission tomography at different levels of adaptation. A significant signal in subtraction images was localized in left Brodmann's area 45 (ventral sub-region of Broca's area) in the initial phase of the mirror drawing. This activity decreased as adaptation proceeded, and a small cluster in area 19 of the medial extrastriate cortex became significantly active. An after-effect of ca. 30 min of mirror-drawing was also detected in the right area 21 of the temporal association cortex. The results first demonstrated visuo-cortical regions where neurons might change their activity to evoke plastic response to the inverted vision.

Psychological factors related to health, back pain, and dysfunction.

Psychosocial variables may be important determinants of experienced back pain as well as dysfunction. This paper reports on differences on a battery of psychosocial variables between women, from the same work place, off work because of back pain, having only back pain (not off work), and those without back pain. The groups suffering pain had similar levels of pain intensity and frequency and the covariates of age and work load were used in MANCOVA analyses. The results showed significant overall differences on the Coping Strategies Questionnaire, Handicap Index, Duke Health Profile, as well as items concerning family support and the relation of pain to work. Several variables differed between the Healthy group on the one hand and the two groups suffering pain on the other hand. However, coping strategies and perceived health produced significant differences between all three groups in univariate analyses. Unlike other studies the Work APGAR produced no significant results. These data suggest that work status is not directly related to pain intensity, but rather to an interaction between psychosocial factors and the pain experience. Future research should delineate which variables may be used in screening.