Search PubMed⌕ Search

Biomedical subjects

F Moss

Publications and source records attributed to F Moss.

At least 19 recordsLinked to original sources
PubMed2001

Behavioral stochastic resonance: how a noisy army betrays its outpost.

Juvenile paddlefish prey upon single zooplankton by detecting a weak electric signature resulting from its feeding and swimming motions. Moreover, it has recently been shown that paddlefish make use of stochastic resonance near the threshold for prey detection: a process termed behavioral stochastic resonance. But this process depends upon an external source of electric noise. A swarm of plankton, for example, Daphnia, can provide this noise. Assuming that juvenile paddlefish attack single Daphnia as outliers in the vicinity of the swarm, making use of noise from the swarm, we calculate the spatial distribution of the average phase locking period for the subthreshold signals acting at the paddlefish rostrum. Numeric evaluation of analytic formulas supports the notion of a noise-induced widening of the capture area quantitatively.

Algorithms↗
PubMed2000

Stochastic resonance enhances the electrosensory information available to paddlefish for prey capture.

Recent behavior experiments have demonstrated that paddlefish can make use of stochastic resonance while feeding on Daphnia plankton. Here we calculate the information content of the noisy Daphnia signal at the paddlefish rostrum using an exact statistical treatment of threshold stochastic resonance as a minimal neural model. These calculations compare well with experimentally obtained data on paddlefish strikes at Daphnia prey.

Animals↗
PubMed2000

Detecting the onset of bifurcations and their precursors from noisy data

We study the problem of the detection of noise-induced precursors of periodic motion instabilities in stochastic dynamical systems. In particular, we concentrate on the period-doubling bifurcation. We have developed a statistical method to detect the onset of bifurcations and their precursors based on the previously established topological recurrence technique.

Journal Article↗
PubMed2000

Quality improvement around the world: how much we can learn from each other.

The USA National Forum on Quality Improvement in Health Care--organised by the Institute of Healthcare Improvement (Boston USA)--attracts many people from outside North America. At the 1999 meeting 20 countries were represented. A session on "Quality improvement around the world" was included in the pre-conference programme to bring together people working in many countries to explore and compare their experiences in a programme of short presentations (table 1). This article draws together some of the themes that emerged from the presentations and from the discussion.

Delivery of Health Care↗
PubMed2000

The effect of 1-year rotations on stress in preregistration house officers.

A comparison of stress levels in preregistration house officers demonstrated lower levels in those completing 1-year rotations compared with those completing 6-month posts in two different hospitals. One-year rotations provide a more stable environment, allow new doctors to become familiar with the workings of an organization from several viewpoints and permit a better sense of working within a multiprofessional team than the traditional arrangements.

Education, Medical, Graduate↗
PubMed1999

Use of behavioural stochastic resonance by paddle fish for feeding.

Stochastic resonance is the phenomenon whereby the addition of an optimal level of noise to a weak information-carrying input to certain nonlinear systems can enhance the information content at their outputs. Computer analysis of spike trains has been needed to reveal stochastic resonance in the responses of sensory receptors except for one study on human psychophysics. But is an animal aware of, and can it make use of, the enhanced sensory information from stochastic resonance? Here, we show that stochastic resonance enhances the normal feeding behaviour of paddlefish (Polyodon spathula), which use passive electroreceptors to detect electrical signals from planktonic prey. We demonstrate significant broadening of the spatial range for the detection of plankton when a noisy electric field of optimal amplitude is applied in the water. We also show that swarms of Daphnia plankton are a natural source of electrical noise. Our demonstration of stochastic resonance at the level of a vital animal behaviour, feeding, which has probably evolved for functional success, provides evidence that stochastic resonance in sensory nervous systems is an evolutionary adaptation.

Animals↗
PubMed1998

Human autoantibodies specific for the alpha1A calcium channel subunit reduce both P-type and Q-type calcium currents in cerebellar neurons.

The pharmacological properties of voltage-dependent calcium channel (VDCC) subtypes appear mainly to be determined by the alpha1 pore-forming subunit but, whether P-and Q-type VDCCs are encoded by the same alpha1 gene presently is unresolved. To investigate this, we used IgG antibodies to presynaptic VDCCs at motor nerve terminals that underlie muscle weakness in the autoimmune Lambert-Eaton myasthenic syndrome (LEMS). We first studied their action on changes in intracellular free Ca2+ concentration [Ca2+]i in human embryonic kidney (HEK293) cell lines expressing different combinations of human recombinant VDCC subunits. Incubation for 18 h with LEMS IgG (2 mg/ml) caused a significant dose-dependent reduction in the K+-stimulated [Ca2+]i increase in the alpha1A cell line but not in the alpha1B, alpha1C, alpha1D, and alpha1E cell lines, establishing the alpha1A subunit as the target for these autoantibodies. Exploiting this specificity, we incubated cultured rat cerebellar neurones with LEMS IgG and observed a reduction in P-type current in Purkinje cells and both P- and Q-type currents in granule cells. These data are consistent with the hypothesis that the alpha1A gene encodes for the pore-forming subunit of both P-type and Q-type VDCCs.

Animals↗