Tough and Stretchy: Mechanical Properties of the Alimentary Tract in a Fish Without a Stomach
Bibliographic record
Abstract
Synopsis The mechanical properties of intestinal tissues determine how a thin-walled structure exerts forces on food and absorbs the force of food as it enters and travels down the gut. These properties are critically important in durophagous and stomachless fish, which must resist the potential damage to foreign bodies (e.g., shells fragments) in their diet. We test the hypothesis that the mechanical properties of the alimentary tract will differ along its length. We predict that the proximal region of the gut should be the strongest and most extensible to handle the large influx of prey often associated with stomachless fish that lack a storage depot. We developed a custom inflation technique to measure the passive mechanical properties of the whole intestine of the stomachless shiner perch, Cymatogaster aggregata. We show that mechanical properties differ significantly along the length of the alimentary tract when inflated to structural failure, with 25–46% greater maximal stress, strain, extension ratio, and toughness at the proximal (25%) position. We also find that the alimentary tissues (excluding the heavily muscular rectum) are generally highly extensible and anisotropic, and do not differ in wall circumference or thickness along the alimentary tract. These findings contribute to our knowledge of the mechanical properties of fish intestinal tissues and guide future studies of factors influencing the evolution of fish alimentary systems.
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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 | 0.000 |
| 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) | 0.002 | 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".