Differences in management of telemedicine alerts on weekdays and public holidays: Results from the OptiLink heart failure trial

Background In the OptiLink heart failure study, timely and appropriate reactions to telemedicine alerts improved clinical outcomes in heart failure patients. This analysis investigates the relation between the weekday of alert transmission and the subsequent patient contact. Methods In patients enrolled in the intervention arm of the OptiLink heart failure study ( n = 505, age 66.1 ± 10.1, 77.2% male, left-ventricular ejection fraction 26.7% ± 6.1%), fluid index threshold crossing alerts were analysed according to the weekday of the transmission. Transmissions on Mondays–Thursdays were categorized as TD1, Fridays–Sundays as well as public holidays as TD2. Results Of 1365 transmitted alerts, 867 (63.5%) were categorized as TD1 and 498 (36.5%) as TD2. Same day telephone contacts were more frequent in TD1 (46.2%) than in TD2 (18.3%; p < 0.001). Accordingly, the median time to contact was significantly longer in TD2 compared with TD1 (2(1–3) vs 0(0–1) days; p < 0.001). Rates of no telephone contact were no different between the groups (12.1% vs 12.4%; p = 0.866). Although signs of worsening heart failure were prevalent in 32.4% in TD1 versus 32.1% in TD2 ( p = 0.996), initiation of a pharmacological intervention occurred more likely in TD1 compared with TD2 (27.9% vs 22.9%; p = 0.041). No differences existed concerning hospitalization for heart failure within 30 days after alert transmission (3.9% vs 3.4%; p = 0.636). Conclusion Alert transmissions during weekends and public holidays were less likely associated with timely patient contacts and initiation of pharmacological interventions than during the week. Telemedical centres providing 24/7 remote monitoring service and specific education programmes for physicians might help to optimize patient care.

The Threshold-Crossing Effect: Just-Below Pricing Discourages Consumers to Upgrade

Managers often set prices just-below a round number (e.g., $39) – a strategy that lowers price perceptions and increases sales. The authors question this conventional wisdom in a common consumer context: upgrade decisions (e.g., whether to upgrade a car or hotel room). Seven studies—including one field study—provide empirical evidence for a threshold-crossing effect. When a base product is priced at or just-above a threshold, consumers are more likely to upgrade and spend more money (studies 1–3) because they perceive the upgrade option as less expensive (study 4), and they place less weight on price (study 5). Testing theoretically motivated and managerially relevant boundary conditions, studies find that the threshold-crossing effect is mitigated under sequential choice (study 6) and when an upgrade price crosses an upper threshold (study 7). These studies demonstrate that a small increase in price on a base product can decrease price perceptions of an upgrade option and, thus, increase consumers’ likelihood to upgrade. It suggests that just-below pricing, while sometimes advantageous at first, may not always be an optimal strategy for managers trying to encourage consumers to ultimately choose an upgrade option.

Exact distribution of threshold-crossing times for protein concentrations: Implication for biological timekeeping

Stochastic transcription and translation dynamics of protein accumulation up to some concentration threshold sets the timing of many cellular physiological processes. Here we obtain the exact distribution of first threshold-crossing times of protein concentration, in either Laplace or time domain, and its associated cumulants: mean, variance and skewness. The distribution is asymmetric and its skewness non-monotonically varies with the threshold. We study lysis times of E-coli cells for holin gene mutants of bacteriophage-λ and find a good match with theory. Mutants requiring higher holin thresholds show more skewed lysis time distributions as predicted.

Feedback autoregulation of gene expression always amplifies noise in timing of threshold crossing

Many cellular events occur when their corresponding regulatory proteins attain critical thresholds. Can cells schedule such events with precision by controlling the dynamics of the proteins? We investigate this question by considering a simple gene expression model that consists of switching the gene between OFF and ON states and degradation of the protein. Because feedback regulation is a pervasive method of control in biological systems, we analyzed three feedback mechanisms (protein regulates either its own transcription, or the rate at which gene turns ON, or the rate at which gene turns OFF) for their abilities to suppress noise in timing. We show that in the limiting case where the protein does not degrade, feedbacks always amplify noise in event timing.

Prediction of Paroxysmal Atrial Fibrillation From Complexity Analysis of the Sinus Rhythm ECG: A Retrospective Case/Control Pilot Study

Paroxysmal atrial fibrillation (PAF) is the most common cardiac arrhythmia, conveying a stroke risk comparable to persistent AF. It poses a significant diagnostic challenge given its intermittency and potential brevity, and absence of symptoms in most patients. This pilot study introduces a novel biomarker for early PAF detection, based upon analysis of sinus rhythm ECG waveform complexity. Sinus rhythm ECG recordings were made from 52 patients with (n = 28) or without (n = 24) a subsequent diagnosis of PAF. Subjects used a handheld ECG monitor to record 28-second periods, twice-daily for at least 3 weeks. Two independent ECG complexity indices were calculated using a Lempel-Ziv algorithm: R-wave interval variability (beat detection, BD) and complexity of the entire ECG waveform (threshold crossing, TC). TC, but not BD, complexity scores were significantly greater in PAF patients, but TC complexity alone did not identify satisfactorily individual PAF cases. However, a composite complexity score (h-score) based on within-patient BD and TC variability scores was devised. The h-score allowed correct identification of PAF patients with 85% sensitivity and 83% specificity. This powerful but simple approach to identify PAF sufferers from analysis of brief periods of sinus-rhythm ECGs using hand-held monitors should enable easy and low-cost screening for PAF with the potential to reduce stroke occurrence.

A comprehensive computational model of animal biosonar signal processing

Computational models of animal biosonar seek to identify critical aspects of echo processing responsible for the superior, real-time performance of echolocating bats and dolphins in target tracking and clutter rejection. The Spectrogram Correlation and Transformation (SCAT) model replicates aspects of biosonar imaging in both species by processing wideband biosonar sounds and echoes with auditory mechanisms identified from experiments with bats. The model acquires broadband biosonar broadcasts and echoes, represents them as time-frequency spectrograms using parallel bandpass filters, translates the filtered signals into ten parallel amplitude threshold levels, and then operates on the resulting time-of-occurrence values at each frequency to estimate overall echo range delay. It uses the structure of the echo spectrum by depicting it as a series of local frequency nulls arranged regularly along the frequency axis of the spectrograms after dechirping them relative to the broadcast. Computations take place entirely on the timing of threshold-crossing events for each echo relative to threshold-events for the broadcast. Threshold-crossing times take into account amplitude-latency trading, a physiological feature absent from conventional digital signal processing. Amplitude-latency trading transposes the profile of amplitudes across frequencies into a profile of time-registrations across frequencies. Target shape is extracted from the spacing of the object’s individual acoustic reflecting points, or glints, using the mutual interference pattern of peaks and nulls in the echo spectrum. These are merged with the overall range-delay estimate to produce a delay-based reconstruction of the object’s distance as well as its glints. Clutter echoes indiscriminately activate multiple parts in the null-detecting system, which then produces the equivalent glint-delay spacings in images, thus blurring the overall echo-delay estimates by adding spurious glint delays to the image. Blurring acts as an anticorrelation process that rejects clutter intrusion into perceptions.

A comprehensive computational model of animal biosonar signal processing

Computational models of animal biosonar seek to identify critical aspects of echo processing responsible for the superior, real-time performance of echolocating bats and dolphins in target tracking and clutter rejection. The Spectrogram Correlation and Transformation (SCAT) model replicates aspects of biosonar imaging in both species by processing wideband biosonar sounds and echoes with auditory mechanisms identified from experiments with bats. The model acquires broadband biosonar broadcasts and echoes, represents them as time-frequency spectrograms using parallel bandpass filters, translates the filtered signals into ten parallel amplitude threshold levels, and then operates on the resulting time-of-occurrence values at each frequency to estimate overall echo range delay. It uses the structure of the echo spectrum by depicting it as a series of local frequency nulls arranged regularly along the frequency axis of the spectrograms after dechirping them relative to the broadcast. Computations take place entirely on the timing of threshold-crossing events for each echo relative to threshold-events for the broadcast. Threshold-crossing times take into account amplitude-latency trading, a physiological feature absent from conventional digital signal processing. Amplitude-latency trading transposes the profile of amplitudes across frequencies into a profile of time-registrations across frequencies. Target shape is extracted from the spacing of the object’s individual acoustic reflecting points, or glints, using the mutual interference pattern of peaks and nulls in the echo spectrum. These are merged with the overall range-delay estimate to produce a delay-based reconstruction of the object’s distance as well as its glints. Clutter echoes indiscriminately activate multiple parts in the null-detecting system, which then produces the equivalent glint-delay spacings in images, thus blurring the overall echo-delay estimates by adding spurious glint delays to the image. Blurring acts as an anticorrelation process that rejects clutter intrusion into perceptions.Author summaryBats and dolphins use their biological sonar as a versatile, high-resolution perceptual system that performs at levels desirable in man-made sonar or radar systems. To capture the superior real-time capabilities of biosonar so they can be imported into the design of new man-made systems, we developed a computer model of the sonar receiver used by echolocating bats and dolphins. Our intention was to discover the processing methods responsible for the animals’ ability to find and identify targets, guide locomotion, and prevent classic types of sonar or radar interference that hamper performance of man-made systems in complex, rapidly-changing surroundings. We have identified several features of the ears, hearing, time-frequency representation, and auditory processing that are critical for organizing echo-processing methods and display manifested in the animals’ perceptions.

Early prediction of impending septic shock in children using age-adjusted Sepsis-3 criteria

Sepsis is a syndrome which afflicts both adults and children, with many disease courses and diverse outcomes. Understanding of sepsis pathophysiology has changed over time; the Sepsis-3 criteria define sepsis in adults as organ dysfunction, quantified by SOFA score, caused by dysregulated immune response to infection. However, pediatric consensus definitions still utilize the SIRS-based Sepsis-2 criteria, though individual groups have attempted to adapt the Sepsis-3 criteria for children. We evaluate age-adjusted Sepsis-3 criteria on 2,384 pediatric patients admitted to the Johns Hopkins PICU, and apply previously-published methods for early prediction of septic shock. We obtain best early prediction performance of 0.96 AUC, 49.9% overall PPV, and a 5.8-hour median EWT using Sepsis-3 labels based on age-adjusted SOFA score. Through analyses of risk score evolution over time, we corroborate our past finding of an abrupt transition preceding onset of septic shock in children, and are able to stratify pediatric sepsis patients using their first post-threshold-crossing risk score.

Unknowingly, A threshold-crossing movement

It is in this special issue that the editorial board holds true to our promise to expand the horizons and readership of idea journal while reaching out to associated and adjacent art, design and performance practices and drawing connections to seemingly distant disciplines. The articles in this issue have provenance in a 2019 conference event, Bodies of Knowledge (BOK), which was guided by a similar interdisciplinary ethos. With an emphasis on cultures of practice and communities of practitioners that offer perspectives on inclusion, diversity/neurodiversity and disability, this conference, and this subsequent journal issue, aim to increase knowledge transfer between diverse forms of embodied expertise, in particular, between neuroscience and enactive theories of cognition.