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Janet Fischer

Publications and source records attributed to Janet Fischer.

5 recordsLinked to original sources
PubMed2006

Detection of scale-specific community dynamics using wavelets.

The response of ecological communities to anthropogenic disturbance is of both scientific and practical interest. Communities where all species respond to disturbance in a similar fashion (synchrony) will exhibit large fluctuations in total biomass and dramatic changes in ecosystem function. Communities where some species increase in abundance while others decrease after disturbance (compensation) can maintain total biomass and ecosystem function in the face of anthropogenic change. We examined dynamics of the Little Rock Lake (Wisconsin, USA) zooplankton community in the context of an experimental pH manipulation conducted in one basin of the lake. A novel application of wavelets was used to partition patterns of synchrony and compensation by time scale. We find interestingly that some time series show both patterns of synchrony and compensation depending on the scale of analysis. Within the unmanipulated basin, we found subtle patterns of synchrony and compensation within the community, largely at a one-year time scale corresponding to seasonal variation. Within the acidified lake basin, dynamics shifted to longer time scales corresponding to the pattern of pH manipulation. Comparisons between pairs of species in different functional groups showed both strong compensatory and synchronous responses to disturbance. The strongest compensatory signal was observed for two species of Daphnia whose life history traits lead to synchrony at annual time scales, but whose differential sensitivity to acidification led to compensation at multiannual time scales. The separation of time scales inherent in the wavelet method greatly facilitated interpretation as patterns resulting from seasonal drivers could be separated from patterns driven by pH manipulation.

Animals↗
PubMed2004

Nutrition support in the morbidly obese, critically ill patient.

Nutrition support in the critically ill patient is challenging but is even more difficult in a morbidly obese patient. This case report chronicles the care of a 6-foot-tall, 256-kg male (body mass index 76.5 kg/m(2)) who spent over a month in the intensive care unit for respiratory failure, sepsis, and acute renal failure. Parenteral nutrition was provided throughout his critical care course. One of the major difficulties encountered was determining his nutritional needs. A hypocaloric nutritional regimen was used, along with moderate protein provisions. Numerous electrolyte imbalances occurred, including hypercalcemia that did not resolve by eliminating calcium from the parenteral nutrition solution. Enteral nutrition was desired but was not used initially because of a need for vasopressors, a diagnosis of pancreatitis, difficulty in documenting feeding tube placement because of diagnostic limitations secondary to the patient's large size, and concern about managing stools. Eventually, oral intake and supplemental enteral feeding were initiated. Nutrition support team members worked closely with the interdisciplinary care team to develop strategies to manage the nutritional problems related to his obesity. A discussion of the various nutritional issues encountered in the care of this patient is provided. Reasonable nutritional status was achieved, but this case reflects some of the challenges encountered in caring for the nutritional needs of select patient populations in clinical practice and the need for increased research and guidelines in this area.

Journal Article↗