Seismocardiograms return valid heart rate variability indices
Bibliographic record
Abstract
HRV indices have traditionally been acquired using interbeat intervals obtained from the electrocardiogram (ECG) R-wave. Preliminary studies have recently shown, however, that interbeat intervals obtained from seismocardiogram (SCG) isovolumic moment point return some valid HRV measurements. This presents an interesting discovery due to the recent ubiquity of affordable accelerometers of satisfactory sensitivity in mobile phones. For this purpose an orthostatic stress test of graded lower body negative pressure (LBNP) was used to compare HR V indices obtained from ECG and SCG during periods of different orthostatic stress. We conclude that estimates of interbeat intervals obtained using SCG markers are valid measurements of interbeat interval when compared with ECG and lend themselves validly to time-domain and frequency-domain HRV analysis. It is our recommendation that aortic opening SCG markers be used to obtain interbeat intervals as they represent well defined events and are obtainable without the use of ECG markers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".