CO <sub>2</sub> rebreathing: an undergraduate lab to study the chemical control of breathing
Bibliographic record
Abstract
Duffin and McAvoy's (1988) modification of the Read (1967) CO 2 rebreathing (CO 2 RB) method is widely used to study chemical control of breathing (ChemoCB). We used a CO 2 RB laboratory to challenge undergraduate science majors (to investigate the ChemoCB). We collated and analyzed 8 years of data to study the reproducibility of the laboratory and compared the results to the literature. Students (aged 19–21 yrs; IRB approval) performed the technique using a rebreathing bag containing 95% O 2 to suppress peripheral chemoreceptor activity. Ventilation was measured following hyperventilation to deplete tissue CO 2 stores, which also enhances detection of the central chemoreflex threshold (CCT). Data were analyzed by 3 investigators. Of 37 data sets, 7 were rejected due to technical issues. CO 2 sensitivity and CCT were 4.69±3.12 L/min/mmHg (mean±SD) and 43.5±3.9 mmHg respectively. The CCT was normally distributed, whereas sensitivity was skewed to the left. Values agree well with those reported by Duffin & McAvoy (1988). We conclude CO 2 RB is a robust method for undergraduate investigation of the principles of chemical control of breathing. Funded by Queen's University, NSERC and CIHR.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".