Bibliographic record
Abstract
River weirs are low-head dams that dissipate energy by creating hydraulic recirculation zones at their base. These recirculation zones are a major cause of human drownings and have been referred to as “drowning machines”. We observed an event that allowed us to add ducklings to the list of weir victims. As a Mallard (Anas platyrhynchos) hen and her brood floated over the Calgary weir, the mother flew safely over the hydraulic recirculation. The ducklings drifted into the recirculation and three quickly passed through; four were stalled, repeatedly recirculated, and died. We observed other regional weirs where adult birds commonly flew over the hazard. We did not observe any other waterfowl drifting into recirculation zones, and we found no prior report of this lethal hazard. Although mortality might be rare at each weir, with hundreds of thousands of low-head dams worldwide, the collective hazard could be substantial. Weirs can be designed to eliminate the lethal recirculation zone, and the apparent hazard to ducklings could provide another motivation to redesign or modify these common structures.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".