Richard Dewey | PubMed Health

PubMed2006

Observations of biologically generated turbulence in a coastal inlet.

Measurements in a coastal inlet revealed turbulence that was three to four orders of magnitude larger during the dusk ascent of a dense acoustic-scattering layer of krill than during the day, elevating daily-averaged mixing in the inlet by a factor of 100. Because vertically migrating layers of swimming organisms are found in much of the ocean, biologically generated turbulence may affect (i) the transport of inorganic nutrients to the often nutrient-depleted surface layer from underlying nutrient-rich stratified waters to affect biological productivity and (ii) the exchange of atmospheric gases such as CO2 with the stratified ocean interior, which has no direct communication with the atmosphere.

Animal Migration↗

PubMed2002

Cognitive functioning in individuals with "benign" essential tremor.

Essential tremor (ET) is the most common type of movement disorder, although its etiology and neurophysiological substrates remain unclear. While thought to be a benign condition, it has yet to be studied from a neuropsychological perspective. We examined the neurocognitive functioning of 13 nondemented subjects with severe ET, including aspects of memory, cognitive flexibility, and attention. Results revealed that 12/13 subjects demonstrated impairment on 1 or more cognitive measures in comparison with published normative data. The pattern of findings was suggestive of relative dysfunction of frontal-mediated processes not unlike that seen in Parkinson's disease. These deficits were found in subjects irrespective of the presence of cognitive complaints, depression, or the existence of other potential neurocognitive risk factors. These findings suggest that mild cognitive deficits are not uncommon in association with severe ET and may be related to subcortical systems.

Adult↗