The fluvial grain‐size gap: Experimental confirmation of hydraulic origin
Bibliographic record
Abstract
Abstract The origin of the well‐known ‘grain size gap’ within the size range 1–10 mm in fluvial gravels is explored in a laboratory experiment to ascertain the effect of hydraulic sorting. A widely graded sand/gravel mixture was fed into a flume containing a bed composed of the same sediment mixture. The rate of sediment feed was varied but the water flow remained constant throughout the experiment at a rate that sustained size‐selective bedload transport with negligible suspension. We observed persistent deposition of the coarsest sediments (+16 mm) due to lack of competence to mobilize these sizes, partial entrapment of the finest sizes (−1 mm) in interstices of the gravel bed, and preferred transport of the intermediate sizes, including uptake of grains from the bed, establishing the conditions for development of the grain size gap.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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 teacher head, 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".