Autonomic Measures Research Articles

Enhance Ocean Carbon Observations: Successful Implementation of a Novel Autonomous Total Alkalinity Analyzer on a Ship of Opportunity

Over recent decades, observations based on merchant vessels (Ships of Opportunity—SOOP) equipped with sensors measuring the CO2 partial pressure (pCO2) in the surface seawater formed the backbone of the global ocean carbon observation system. However, the restriction to pCO2 measurements alone is one severe shortcoming of the current SOOP observatory. Full insight into the marine inorganic carbon system requires the measurement of at least two of the four measurable variables which are pCO2, total alkalinity (TA), dissolved inorganic carbon (DIC), and pH. One workaround is to estimate TA values based on established temperature-salinity parameterizations, but this leads to higher uncertainties and the possibility of regional and/or seasonal biases. Therefore, autonomous SOOP-based TA measurements are of great interest. Our study describes the implementation of a novel autonomous analyzer for seawater TA, the CONTROS HydroFIAⓇ TA system (-4H-JENA engineering GmbH, Germany) for unattended routine TA measurements on a SOOP line operating in the North Atlantic. We present the installation in detail and address major issues encountered with autonomous measurements using this analyzer, e.g., automated cleaning and stabilization routines, and waste handling. Another issue during long-term deployments is the provision of reference seawater in large-volume containers for quality assurance measurements and drift correction. Hence, a stable large-volume seawater storage had to be found. We tested several container types with respect to their suitability to store seawater over a time period of 30 days without significant changes in TA. Only one gas sampling bag made of polyvinylidene fluoride (PVDF) satisfied the high stability requirement. In order to prove the performance of the entire setup, we compared the autonomous TA measurements with TA from discrete samples taken during the first two trans-Atlantic crossings. Although the measurement accuracy in unattended mode (about ± 5 μmol kg^-1) slightly deteriorated compared to our previous system characterization, its overall uncertainty fulfilled requirements for autonomous TA measurements on SOOP lines. A comparison with predicted TA values based on an established and often used parameterization pointed at regional and seasonal limitations of such TA predictions. Consequently, TA observations with better coverage of spatiotemporal variability are needed, which is now possible with the method described here.

An Instrument Platform for Above-Water Measurements of the Ocean’s Surface and Atmosphere

An automated instrument platform is designed to install remote sensing instruments for measurements made from stationary coastal pedestals or offshore platforms with remote control and transfer of information via the Internet. The platform is of a turret design that can rotate around a fixed base in the range of azimuthal angles up to 300°. Scientific instruments are mounted on the right and left panels of the turret. Each panel can rotate in elevation up to 200°, either independently or synchronously with the other. The design of the panels allows devices to be mounted quickly and their location to be changed easily. Cables supplying power to devices and receiving information pass through the hollow tubes of the gearboxes on which the consoles are held inside the platform in such a way that during rotation they do not interfere with its movement and do not fray. The platform is mounted on roller bearings on rails along which it extends above the water’s surface for measurements. The rotation of the platform is controlled both manually and automatically using a computer and an RS-485 interface. Power is supplied from a +27 V network. The platform can be remotely controlled, and scientific information is collected via the Internet. Examples are given of organizing autonomous measurements of water surface and atmosphere parameters in experiments at the Black Sea Hydrophysical Proving Ground of the Russian Academy of Sciences, which is the only place in the Russian Federation for the calibration and validation of microwave satellite systems.

Autonomous Minisubmarine Measures Seawater Conditions

Forecasts of carbonate chemistry in coastal ecosystems determined from seasonal robotic measurements can improve fisheries management and help mitigate short-term ocean acidification events.

Prone sleeping affects cardiovascular control in preterm infants in NICU.

Prone sleeping is used in preterm infants undergoing intensive care to improve respiratory function, but evidence suggests that this position may compromise autonomic cardiovascular control. To test this hypothesis, this study assessed the effects of the prone sleeping position on cardiovascular control in preterm infants undergoing intensive care treatment during early postnatal life. Fifty-six preterm infants, divided into extremely preterm (gestational age (GA) 24-28 weeks, n = 23) and very preterm (GA 29-34 weeks, n = 33) groups, were studied weekly for 3 weeks in prone and supine positions, during quiet and active sleep. Heart rate (HR) and non-invasive blood pressure (BP) were recorded and autonomic measures of HR variability (HRV), BP variability (BPV), and baroreflex sensitivity (BRS) using frequency analysis in low (LF) and high (HF) bands were assessed. During the first 3 weeks, prone sleeping increased HR, reduced BRS, and increased HF BPV compared to supine. LF and HF HRV were also lower prone compared to supine in very preterm infants. Extremely preterm infants had the lowest HRV and BRS measures, and the highest HF BPV. Prone sleeping dampens cardiovascular control in early postnatal life in preterm infants, having potential implications for BP regulation in infants undergoing intensive care.

MGEODAR-A Mobile Radar System for Detection and Monitoring of Gravitational Mass-Movements.

Radar measurements of gravitational mass-movements like snow avalanches have become increasingly important for scientific flow observations, real-time detection and monitoring. Independence of visibility is a main advantage for rapid and reliable detection of those events, and achievable high-resolution imaging proves invaluable for scientific measurements of the complete flow evolution. Existing radar systems are made for either detection with low-resolution or they are large devices and permanently installed at test-sites. We present mGEODAR, a mobile FMCW (frequency modulated continuous wave) radar system for high-resolution measurements and low-resolution gravitational mass-movement detection and monitoring purposes due to a versatile frequency generation scheme. We optimize the performance of different frequency settings with loop cable measurements and show the freespace range sensitivity with data of a car as moving point source. About 15 dB signal-to-noise ratio is achieved for the cable test and about 5 dB or 10 dB for the car in detection and research mode, respectively. By combining continuous recording in the low resolution detection mode with real-time triggering of the high resolution research mode, we expect that mGEODAR enables autonomous measurement campaigns for infrastructure safety and mass-movement research purposes in rapid response to changing weather and snow conditions.

Comparative analysis of the autonomic nervous system response during movement representation in healthy individuals and patients with chronic low back pain: a prospective cohort study

Objective The primary objective was to compare the difference in autonomic nervous system (ANS) response between motor imagery (MI) group and action observation (AO) group. Both consisted of two subgroups: the control subgroup (CG), which consisted of asymptomatic individuals, and the patient subgroup (PG), which consisted of patients with chronic low back pain (CLBP). The secondary objective was to assess ANS activity during AO and MI training according to the fear-of-movement levels of the PGs. Methods Sixty participants were randomly assigned. The autonomic outcome measures included skin conductance (SC), respiration rate (RR), and heart rate (HR). Results Results showed that intergroup differences in RR were higher in the PG, with a large effect size (p = .007, d = 1.71). Only the PGs showed intragroup differences in SC (p <.05). In terms of ANS activity during the training, there were no statistically significant intergroup differences (p <.05). However, the strongest intragroup differences were among the AOPG with greater levels of kinesiophobia. For the SC and HR variables, only this condition showed significant differences between baseline and the first and second movements, with a large effect size (p <.001 and p = .002, respectively, and d >.80). Conclusions The results showed that AO and MI training in the PG and CG resulted in similar but not identical ANS activation, with slightly higher activation in the PG. The differences in the PG could be associated with kinesiophobia when visually exposed to low-back movements that could be interpreted as hazardous or unsafe.

Identification of soundscape components and their temporal patterns in Kongsfjorden, Svalbard Archipelago

Time series measurements of ocean ambient sound were carried out using an autonomous passive acoustic measurement system deployed in Kongsfjorden, Arctic Ocean, between July 2015 and April 2016. Geophysical soundscape components, particularly that of sea ice melting and wind noise, were identified. The biological sounds produced by walruses in the form of knocking and tapping sequences fall in the range 0.2–4 kHz, and the bearded seal trill loud vocalizations occur between 0.35 and 1.2 kHz. The anthropogenic sources are mainly connected to the passenger and patrol vessels, with sound levels dominant at frequencies below 0.7 kHz. During summer, the sound levels are high due to the combined effect of geophysical and anthropogenic sources, whereas they decrease during the winter and spring seasons since the sea-ice cover effectively shields the sea surface at this time, preventing wind-generated sound. This study illustrates the seasonal variability of the soundscape components, and discusses the relationship of sea ice concentration to ambient sound levels in the Arctic fjords using the passive acoustic monitoring approach.

A new approach for measuring the carbon and oxygen content of atmospherically relevant compounds and mixtures

Abstract. Due to its complexity, gas- and particle-phase organic carbon in the atmosphere is often classified by its bulk physicochemical properties. However, there is a dearth of robust, moderate-cost approaches to measure the bulk chemical composition of organic carbon in the atmosphere. This is particularly true for the degree of oxygenation, which critically affects the properties and impacts of organic carbon but for which routine measurement approaches are lacking. This gap has limited the understanding of a wide range of atmospheric components, including particulate matter, the mass of which is monitored worldwide due to its health and environmental effects but the chemical characterization of which requires relatively high capital costs and complex operation by highly trained technical personnel. In this work, we demonstrate a new approach to estimate the mass of carbon and oxygen in analytes and mixtures that relies only on robust, moderate-cost detectors designed for use with gas chromatography. Organic compounds entering a flame ionization detector were found to be converted with approximately complete efficiency to CO2, which was analyzed downstream using an infrared detector to measure the mass of carbon analyzed. The ratio of the flame ionization detector (FID) signal generated to CO2 formed (FID∕CO2) was shown to be strongly correlated (R2=0.89) to the oxygen-to-carbon ratio (O∕C) of the analyte. Furthermore, simple mixtures of analytes behaved as the weighted average of their components, indicating that this correlation extends to mixtures. These properties were also observed to correlate well with the sensitivity of the FID estimated by structure activity relationships (quantified as the relative effective carbon number). The relationships between measured FID∕CO2, analyte O∕C, and FID sensitivity allow the estimation of one property from another with &lt;15 % error for mixtures and &lt;20 % error for most individual analytes. The approach opens the possibility of field-deployable, autonomous measurement of the carbon and oxygen content of particulate matter using time-tested, low-maintenance detectors, though such an application would require some additional testing on complex mixtures. With some instrumental modifications, similar measurements on gas-phase species may be feasible. Moreover, the potential expansion to additional gas chromatography detectors may provide concurrent measurement of other elements (e.g., sulfur, nitrogen).

Evaluating the potential for autonomous measurements of net community production and calcification as a tool for monitoring coral restoration

As coral restoration efforts increase globally, there is a growing need to not only increase post-restoration monitoring, but also advance reef restoration monitoring methods. Utilizing autonomous technology to compliment manual, SCUBA-based monitoring will diversify the types of data available to coral restoration practitioners and aid in determining the efficacy of restoration efforts. This study sought to investigate how existing reef monitoring technologies can be applied to coral restoration to improve monitoring resolution and assess restoration progress. The Benthic Ecosystem and Acidification Measurement System, which uses the gradient flux approach to measure benthic community metabolism, was used to monitor two arrays of nursery grown Acropora cervicornis within an offshore coral nursery in the Florida Keys. The first deployment monitored corals arranged in a density mimicking pre-restoration coral cover, while the second deployment monitored corals arranged in a density mimicking a reef site recently restored with nursery-grown A. cervicornis. The post-restoration density demonstrated a 36% increase in the observed ratio of net community calcification to net community production as compared to the pre-restoration density. Additionally, the post-restoration density demonstrated net accretion throughout the observation period (20 mmol CaCO3 m−2d−1) as compared to the pre-restoration density which experienced net dissolution (−5.0 mmol CaCO3 m−2d−1). Overall, the results of this study are promising indicators that metabolic monitoring could one day be widely utilized within the coral restoration field to remotely monitor benthic composition changes associated with coral restoration progress over time, providing valuable information to restoration practitioners, stakeholders, and resource managers.

Autonomic and Cardiac Repolarization Lability in Long QT Syndrome Patients.

Long QT-Syndrome (LQTS) patients are at risk of arrhythmias and seizures. We investigated whether autonomic and cardiac repolarization measures differed based on LQTS genotypes, and in LQTS patients with vs. without arrhythmias and seizures. We used 24-h ECGs from LQTS1 (n = 87), LQTS2 (n = 50), and LQTS genotype negative patients (LQTS(-), n = 16). Patients were stratified by LQTS genotype, and arrhythmias/seizures. Heart rate variability (HRV) and QT variability index (QTVI) measures were compared between groups during specific physiological states (minimum, middle, & maximum sympathovagal balance, LF/HF). Results were further tested using logistic regression for each ECG measure, and all HRV measures in a single multivariate model. Across multiple physiological states, total autonomic (SDNN) and vagal (RMSSD, pNN50) function were lower and repolarization dynamics (QTVI) were elevated in LQTS(+), LQTS1, and LQTS2, compared to LQTS(-). Many measures remained significant in the regression models. Multivariate modeling demonstrated that SDNN, RMSSD, and pNN50 were independent markers of LQTS(+) vs. LQTS(-), and SDNN and pNN50 were markers for LQTS1 vs. LQTS(-). During sympathovagal balance (middle LF/HF), RMSSD and pNN50 distinguished LQTS1 vs. LQTS2. LQTS1 patients with arrhythmias had lower total (SDNN) and vagal (RMSSD and pNN50) autonomic function, and SDNN remained significant in the models. In contrast, ECG measures did not differ in LQTS2 patients with vs. without arrhythmias, and LQTS1 and LQTS2 with vs. without seizures. Autonomic (HRV) and cardiac repolarization (QTVI) ECG measures differ based on LQTS genotype and history of arrhythmias in LQTS1. SDNN, RMSSD, and pNN50 were each independent markers for LQTS genotype.

Wireless, Artefact Aware Impedance Sensor Node for Continuous Bio-Impedance Monitoring.

Body bio-impedance is a unique parameter to monitor changes in body composition non-invasively. Continuous measurement of bio-impedance can track changes in body fluid content and cell mass and has widespread applications for physiological monitoring. State-of-the-art implementation of bio-impedance sensor devices is still limited for continuous use, in part, due to artefacts arising at the skin-electrode (SE) interface. Artefacts at the SE interface may arise due to various factors such as motion, applied pressure on the electrode surface, changes in ambient conditions or gradual drying of electrodes. This paper presents a novel bio-impedance sensor node that includes an artefact aware method for bio-impedance measurement. The sensor node enables autonomous and continuous measurement of bio-impedance and SE contact impedance at ten frequencies between 10kHz to 100kHz to detect artefacts at the SE interface. Experimental evaluation with SE contact impedance models using passive 2R1C electronic circuits and also with non-invasive in vivo measurements of SE contact impedance demonstrated high accuracy (with maximum error less than 1.5%) and precision of 0.6 Ω. The ability to detect artefacts caused by motion, vertically applied pressure and skin temperature changes was analysed in proof of concept experiments. Low power sensor node design achieved with 50mW in active mode and only 143μW in sleep mode estimated a battery life of 90 days with a 250mAh battery and duty-cycling impedance measurements every 60 seconds. Our method for artefact aware bio-impedance sensing is a step towards autonomous and unobtrusive continuous bio-impedance measurement for health monitoring at-home or in clinical environments.

Structural covariance of the salience network associated with heart rate variability.

The salience network (SN) anchored by the anterior insula and cingulate is crucial for the autonomic control of body homeostasis. Resting-sate fMRI studies have linked intrinsic SN connectivity with multiple autonomic measures, but little is known about the structural organization of this system relating to cardiac vagal function. To address the above issue, the current study used covariance analysis of MRI-based gray matter volume (GMV) to map structural covariance of SN with two independent datasets, and then determined whether interregional structural connections within SN related to individual differences in vagally-mediated heart rate variability (HRV). The results showed a significant positive association between structural covariance of the SN and vagal component of HRV in two independent samples. More importantly, the conjunction and pooled data analysis revealed that structural correlation from left anterior insula to dorsal anterior cingulate cortex positively interacted with vagally-mediated HRV. The current results demonstrated a crucial role of the SN in the cortical modulation of efferent vagal activity to the heart, and provided new insight into structural neural network implicated in cardiac vagal control.

The potential environmental risks of the utilization of composts from household food waste

Modern technologies (especially with the help of autonomous measurement and control systems) introduced automatic composters for the disposal of household food waste production. Environmental risks connected with the utilization of these composts can be characterized by the high electrical conductivity caused by a presence of sodium chloride in food. Electrical conductivity influences the ecotoxicity of the composts. The presence of pesticides in composted food also represents an important environmental problem. The following pesticides were found in compost samples from household food waste: 1,3,5-triazine, methyl trithion, bifenthrin, bifenox, carbophenothion, pirimicarb, dioxacarb, desmetryn. Pesticide content in composts varied from 0.3 to 16.3μg/kg, the average value being 30.4 ± 10.1μg/kg dry matter. The higher decomposition was found of "modern" pesticides in the composters. The removal of salts can ensure that inhibition will be < 30% while washing with the ratio of 1:3 will result in the inhibition < 5%. However, this way of processing is not effective for other organisms-Poecilia reticulata (mortality 100%) and Daphnia magna (immobilisation 100%) using this procedure as well as washing of the compost in the ratio 3:1.

Temperature Profiling of Waterbodies with a UAV-Integrated Sensor Subsystem

Evaluation of thermal stratification and systematic monitoring of water temperature are required for lake management. Water temperature profiling requires temperature measurements through a water column to assess the level of thermal stratification which impacts oxygen content, microbial growth, and distribution of fish. The objective of this research was to develop and assess the functions of a water temperature profiling system mounted on a multirotor unmanned aerial vehicle (UAV). The buoyancy apparatus mounted on the UAV allowed vertical takeoff and landing on the water surface for in situ measurements. The sensor node that was integrated with the UAV consisted of a microcontroller unit, a temperature sensor, and a pressure sensor. The system measured water temperature and depth from seven pre-selected locations in a lake using autonomous navigation with autopilot control. Measurements at 100 ms intervals were made while the UAV was descending at 2 m/s until it landed on water surface. Water temperature maps of three consecutive depths at each location were created from the measurements. The average surface water temperature at 0.3 m was 22.5 °C, while the average water temperature at 4 m depth was 21.5 °C. The UAV-based profiling system developed successfully performed autonomous water temperature measurements within a lake.

The Human Touch: Using a Webcam to Autonomously Monitor Compliance During Visual Field Assessments.

PurposeTo explore the feasibility of using various easy-to-obtain biomarkers to monitor non-compliance (measurement error) during visual field assessments.MethodsForty-two healthy adults (42 eyes) and seven glaucoma patients (14 eyes) underwent two same-day visual field assessments. An ordinary webcam was used to compute seven potential biomarkers of task compliance, based primarily on eye gaze, head pose, and facial expression. We quantified the association between each biomarker and measurement error, as defined by (1) test–retest differences in overall test scores (mean sensitivity), and (2) failures to respond to visible stimuli on individual trials (stimuli −3 dB or more brighter than threshold).ResultsIn healthy eyes, three of the seven biomarkers were significantly associated with overall (test–retest) measurement error (P = 0.003–0.007), and at least two others exhibited possible trends (P = 0.052–0.060). The weighted linear sum of all seven biomarkers was associated with overall measurement error, in both healthy eyes (r = 0.51, P < 0.001) and patients (r = 0.65, P < 0.001). Five biomarkers were each associated with failures to respond to visible stimuli on individual trials (all P < 0.001).ConclusionsInexpensive, autonomous measures of task compliance are associated with measurement error in visual field assessments, in terms of both the overall reliability of a test and failures to respond on particular trials (“lapses”). This could be helpful for identifying low-quality assessments and for improving assessment techniques (e.g., by discounting suspect responses or by automatically triggering comfort breaks or encouragement).Translational RelevanceThis study explores a potential way of improving the reliability of visual field assessments, a crucial but notoriously unreliable clinical measure.

Oxytocin effects on resting-state heart rate variability in women: The role of childhood rearing experiences

Oxytocin is known for its stress-reducing effects and has been associated with autonomic nervous system measures (ANS) involved in the stress response, such as heart rate variability (HRV). The current study examined the effects of intranasal oxytocin on HRV among women (oxytocin N ​= ​87, placebo N ​= ​86) during rest. Results show that oxytocin reduced RMSSD and low frequency (LF)-HRV, but only in women with positive childhood rearing experiences, and not in women with negative childhood experiences. These findings suggest that oxytocin plays a role in ANS regulation and that childhood rearing experiences may influence oxytocin effects on this stress regulating system.

The Western Eurasian Basin Halocline in 2017: Insights From Autonomous NO Measurements and the Mercator Physical System

AbstractWe present the first sensor‐based profiles of the quasi‐conservative NO parameter obtained with an autonomous ice‐tethered buoy in the Arctic Ocean. Data documented the halocline in the Transpolar Drift and Nansen Basin in 2017. A NO minimum was found in the Nansen Basin on a σ‐horizon of 27.8 kg·m−3 corresponding to the lower halocline, while a lower NO minimum of 380 μM straddled the 27.4 σ‐horizon and marked the cold halocline in the Transpolar Drift. Back trajectories of water parcels encountered along the buoy drift were computed using the Mercator physical system. They suggested that waters within the NO minimum at 27.4 kg·m−3 could be traced back to the East Siberian Sea continental. These trajectories conformed with the prevailing positive phase of the Arctic Oscillation. The base of the lower halocline, at the 27.85 σ‐horizon, corresponded to the density attained in the deepest winter mixed layer north of Svalbard and cyclonically slowly advected from the slope into the central Nansen Basin. The 27.85 σ‐horizon is associated with an absolute salinity of 34.9 g·kg−1, a significantly more saline level than the 34.3 psu isohaline commonly used to identify the base of the lower halocline. This denser and more saline level is in accordance with the deeper winter mixed layers observed on the slopes of Nansen Basin in the last 10 years. A combination of simulations and NO parameter estimates provided valuable insights into the structure, source, and strength of the Arctic halocline.

Sparrow: A Magnetic Climbing Robot for Autonomous Thickness Measurement in Ship Hull Maintenance

The maintenance of ship hulls involves a series of routine tasks during dry-docking that renews its life-time and operating efficiency. One such task is hull inspection, which is always seen as harmful for human operators and a time-consuming task. The shipping maintenance industries started using the robotic solutions in order to reduce the human risk. However, most of such robotic systems cannot operate fully autonomously due to the fact that it requires humans in the loop. On the other hand, an autonomous hull inspection robot, called Sparrow, is presented in this paper. The proposed robot is capable of navigating autonomously on the vertical metal surface and it could perform metal thickness inspection. This article summarizes the robot’s mechanical design, system control, autonomy, and the inspection module. We evaluated the robot’s performance by conducting experimental trials on three different metal plates that varied in thickness. The results indicate that the presented robot achieves significantly better locomotion while climbing, and it can autonomously measure the metal thickness, which significantly reduces the human efforts in real-time.

Weddell Sea Phytoplankton Blooms Modulated by Sea Ice Variability and Polynya Formation

AbstractSeasonal sea ice retreat is known to stimulate Southern Ocean phytoplankton blooms, but depth‐resolved observations of their evolution are scarce. Autonomous float measurements collected from 2015–2019 in the eastern Weddell Sea show that spring bloom initiation is closely linked to sea ice retreat timing. The appearance and persistence of a rare open‐ocean polynya over the Maud Rise seamount in 2017 led to an early bloom and high annual net community production. Widespread early ice retreat north of Maud Rise in 2017, however, had a similar effect, suggesting that the polynya most impacted the timing of bloom initiation. Still, higher productivity rates at Maud Rise relative to the surrounding region are observed in all years, likely supported by flow‐topography interactions. The longer growing season in 2017–2018 also allowed for separation of distinct spring and fall bloom signals, the latter of which was primarily subsurface and associated with mixed‐layer deepening.

Autonomic nervous system activity predicts increasing serum cytokines in children

Systemic inflammation is associated with increased risk for prevalent and costly diseases, and animal models implicate the autonomic nervous system in the control of inflammatory processes. In humans, research on autonomic-immune connections has been much more limited, and has focused on single branch autonomic measures (i.e., either parasympathetic or sympathetic). The current study utilized cardiac autonomic balance (CAB), derived from dual-branch cardiac autonomic recordings, to test the relation between resting autonomic function and inflammatory reactivity to challenge in children. MethodsParticipants included 96 children (51 boys, 45 girls) ages 9–11 years (mean age = 9.93 years, SD = 0.57 years). CAB values were calculated from standardized measures of parasympathetic and sympathetic activity, namely resting respiratory sinus arrhythmia and pre-ejection period data, respectively. Children provided two blood samples, one before and one following exposure to an acute social stressor or control condition. Serum was assayed for four cytokines that orchestrate inflammation: interleukin-6 (IL6), interleukin-8 (IL8), interleukin-10 (IL10), and tumor necrosis factor-alpha (TNFa). ResultsWe discovered large individual differences in inflammatory marker production across children, and no average main effect of stress condition. CAB significantly predicted these individual differences, such that children lower on CAB showed increasing serum cytokines from time 1 to time 2. In contrast, children with greater CAB tended to show declining inflammatory markers across the session. DiscussionLow cardiac autonomic balance (i.e., the combination of low parasympathetic and high sympathetic activity) may be a useful marker of proinflammatory tendencies in children, suggesting novel paths for early risk detection and intervention.