The relay (on-off) controller can stabilize wide ranges of processes including open-loop stable, integrating, and unstable processes, producing sustained oscillations. For improved proportional-integral-derivative controller tunings, methods to find process models with mixed closed-loop tests of relay feedback and proportional-derivative (PD) controllers are proposed. For unknown processes with arbitrary initial states, relay feedback tests are first applied and, after cyclic steady states are obtained, PD controllers or other relay feedback tests with set point changes are followed. This full closed-loop operation is desirable for integrating and unstable processes and will be useful even for stable processes when processes are far from their desirable operating points. Refined methods to find exact frequency responses of processes from initial and final cyclic steady states are derived. Whole relay feedback responses need not be saved. Several integrals at the relay switching times are used without iterative tests or computations.
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http://dx.doi.org/10.1021/acsomega.9b02732 | DOI Listing |
bioRxiv
December 2024
Department of Molecular and Cellular Physiology and Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA.
Injured epithelial organs must rapidly replace damaged cells to restore barrier integrity and physiological function. In response, injury-born stem cell progeny differentiate faster compared to healthy-born counterparts, yet the mechanisms that pace differentiation are unclear. Using the adult Drosophila intestine, we find that injury speeds cell differentiation by altering the lateral inhibition circuit that transduces a fate-determining Notch signal.
View Article and Find Full Text PDFBackground: The goal of this study was to examine the effects of spinal cord stimulation (SCS) on muscle activity during walking after lower-limb amputation. Amputation results in a loss of sensory feedback and alterations in gait biomechanics, including co-contractions of antagonist muscles about the knee and ankle, and reduced pelvic obliquity range-of-motion and pelvic drop. SCS can restore sensation in the missing limb, but its effects on muscle activation and gait biomechanics have not been studied in people with lower-limb amputation.
View Article and Find Full Text PDFJ Neurosci
January 2025
Department of Biology, University of Miami, Coral Gables, FL 33143 USA
Neuroendocrine cells react to physical, chemical, and synaptic signals originating from tissues and the nervous system, releasing hormones that regulate various body functions beyond the synapse. Neuroendocrine cells are often embedded in complex tissues making direct tests of their activation mechanisms and signaling effects difficult to study. In the nematode worm , four uterine-vulval (uv1) neuroendocrine cells sit above the vulval canal next to the egg-laying circuit, releasing tyramine and neuropeptides that feedback to inhibit egg laying.
View Article and Find Full Text PDFElife
December 2024
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
Hearing involves analyzing the physical attributes of sounds and integrating the results of this analysis with other sensory, cognitive, and motor variables in order to guide adaptive behavior. The auditory cortex is considered crucial for the integration of acoustic and contextual information and is thought to share the resulting representations with subcortical auditory structures via its vast descending projections. By imaging cellular activity in the corticorecipient shell of the inferior colliculus of mice engaged in a sound detection task, we show that the majority of neurons encode information beyond the physical attributes of the stimulus and that the animals' behavior can be decoded from the activity of those neurons with a high degree of accuracy.
View Article and Find Full Text PDFCureus
November 2024
Pediatrics, Valley Children's Healthcare, Madera, USA.
Introduction: Effective handoff between pediatric residents is crucial to ensure continuity of care and patient safety. Omissions in information and communication breakdowns can be associated with uncertainty in clinical decision-making and adverse patient events. In our role as chief residents, we were notified of an increase in patient safety alerts due to communication failures and gaps during handoff.
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