Radon in air and water

Radon is a natural radioactive gas that you cannot see, smell, or taste and that can only be detected with special equipment. It is produced by the radioactive decay of radium, which in turn is derived from the radioactive decay of uranium. Uranium is found in small quantities in all soils and rocks, although the amount varies from place to place. Radon decays to form radioactive particles that can enter the body by inhalation. Inhalation of the short-lived decay products of radon has been linked to an increase in the risk of developing cancers of the respiratory tract, especially of the lungs. Breathing radon in the indoor air of homes contributes to about 15,000 lung cancer deaths each year in the United States and 1,100 in the UK (HPA 2009). Only smoking causes more lung cancer deaths

The sensorimotor strategies and neuronal representations of tactile shape discrimination in mice

SummaryHumans and other animals can identify objects by active touch, requiring the coordination of exploratory motion and tactile sensation. The brain integrates movements with the resulting tactile signals to form a holistic representation of object identity. We developed a shape discrimination task that challenged head-fixed mice to discriminate concave from convex shapes. Behavioral decoding revealed that mice did this by comparing contacts across whiskers. In contrast, mice performing a shape detection task simply summed up contacts over whiskers. We recorded populations of neurons in the barrel cortex, which processes whisker input, to identify how it encoded the corresponding sensorimotor variables. Neurons across the cortical layers encoded touch, whisker motion, and task-related signals. Sensory representations were task-specific: during shape discrimination, neurons responded most robustly to behaviorally relevant whiskers, overriding somatotopy. We suggest a similar dynamic modulation may underlie object recognition in other brain areas and species.</jats:p