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Biology subjects

Edwards, M. A.

Publications and source records attributed to Edwards, M. A..

2 recordsLinked to original sources

Time-dependent memory and individual variation in Arctic brown bears (Ursus arctos)

1Animal movement modelling provides unique insight about how animals perceive their landscape and how this perception may influence space use. When coupled with data describing an animals environment, ecologists can fit statistical models to location data to describe how spatial memory informs movement. We performed such an analysis on a population of brown bears (Ursus arctos) in the Canadian Arctic using a model incorporating time-dependent spatial memory patterns. Brown bear populations in the Arctic lie on the periphery of the species range, and as a result endure harsh environmental conditions. In this kind of environment, effective use of memory to inform movement strategies could spell the difference between survival and mortality. The model we fit tests four alternate hypotheses (some incorporating memory; some not) against each other, and we found a high degree of individual variation in how brown bears used memory. We found that 52% (11 of 21) of the bears used complex, time-dependent spatial memory to inform their movement decisions. These results, coupled with existing knowledge on individual variation in the population, highlight the diversity of foraging strategies for Arctic brown bears while also displaying the inference that can be drawn from this innovative movement model.

ecology↗

Cooperative electrolyte-PEG interactions drive the signal amplification in a solid-state nanopore

Nanopore systems have emerged as a leading platform for the analysis of biomolecular complexes with single molecule resolution. However, the analysis of several analytes like short nucleic acids or proteins with nanopores represents a sensitivity challenge, because their translocation lead to small signals difficult to distinguish from the noise. Here, we report a simple method to enhance the signal to noise ratio in nanopore experiments by a simple modification of the solution used in nanopore sensing. The addition of poly-ethylene glycol (PEG) and the careful selection of the supporting electrolyte leads to large signal enhancement. We observed that the translocation dynamics are in good agreement with an established method that uses the lattice energy of an electrolyte to approximate the affinity of an ion to PEG. We identified CsBr as the optimal supporting electrolyte to complement PEG to enable the analysis of dsDNA at 500 kHz bandwidth, and the detection of dsDNA as short as 75 bp.

biophysics↗