6 research outputs found
Interception and Retention of Chernobyl-derived 134-Cs, 137Cs and 106Ru in a Spruce Stand.
The time dependence of the specific activity of Chernobyl-derived 134Cs, 137Cs and 106Ru was determined in vegetation and soil samples from an old spruce stand within a period of 600 days after the beginning of the radioactive fallout. The results show that 70% of the total activity of radiocesium and 60% of radioruthenium deposited in the spruce stand were retained intinially in the canopy. They were removed from the needles and twigs as a result of weathering (rain, wind, litter fall) and transferred to the forest floor, but only rather slowly (half-lives in the canopy: radiocesium, 90 days for the period 0–130 days, 230 days for the period 130–600 days; radioruthenium, 95 days for the period 0–200 days). The transfer of radiocesium and ruthenium to the forest floor by litter-fall was small when compared with that of weathering by rain or wind (radiocesium 7%, radioruthenium 8%, with respect to the total activity deposited in the canopy). The total deposition of radiocesium and ruthenium in the spruce stand was higher by 20 and 24%, respectively, than that observed in nearby grassland. The deposition velocity of radiocesium in the spruce stand was estimated at 5.5 mm s−1, higher by a factor of 10 than the figure for grassland. Similar values were found for radiorutheniu
Diminished prefrontal cortex activation in patients with binge eating disorder associates with trait impulsivity and improves after impulsivity-focused treatment based on a randomized controlled IMPULS trial.
BackgroundBehavioral
and cognitive control are vital for healthy eating behavior. Patients
with binge eating disorder (BED) suffer under recurrent binge eating
episodes accompanied by subjective loss of control that results, among
other factors, from increased impulsivity.MethodsIn
the current study, we investigated the frontal network using functional
near-infrared spectroscopy (fNIRS) during a food specific go/nogo task
to assess response inhibition in 24 patients with BED (BMI range
22.6â59.7 kg/m2) compared to 12 healthy controls (HC) (BMI range 20.9â27 kg/m2).
Patients with BED were invited to undergo fNIRS measurements before an
impulsivity-focused cognitive behavioral group treatment, directly after
this treatment and 3 months afterwards. As this was a planned subgroup
analysis of the randomized controlled IMPULS trial, patients with BED
were randomized either to the treatment group (n = 14) or to a control
group (n = 10). The treatment group received 8 weekly sessions of the
IMPULS treatment.ResultsWe found a significant response inhibition effect (nogo minus go),
in terms of an increased oxygenated hemoglobin response in the
bilateral prefrontal cortex in both groups. The greatest response was
observed when participants were instructed to go for healthy and
withhold their response to unhealthy high caloric food cues. The healthy
nogo condition failed to show a significant prefrontal inhibitory
response, which was probably related to the task design, as the
condition was considered more demanding. BED patients, especially those
with higher trait impulsivity, showed a weaker activation of the
prefrontal cortex during response inhibition, predominantly in the right
hemisphere. Interestingly, three months after the treatment, patients
of the treatment group increased their right prefrontal cortex activity
during response inhibition. Likewise, increased prefrontal cortex
activation correlated with decreased trait impulsivity after treatment.ConclusionsOur
results suggest that patients with BED have limited resources to
activate the prefrontal cortex when asked to inhibit a reaction onto
food-specific stimuli. However, this effect could be partly driven by
differences in BMI between the HC and BED group. Cognitive-behavioral
therapy targeting impulsive eating behavior may improve prefrontal
cortex recruitment during response inhibition