Finite-element analysis of simulated ammonoid septa (extinct Cephalopoda): septal and sutural complexities do not reduce strength
Bibliographic record
Abstract
Finite-element analysis of circular septum models indicates that (1) anticlastic fluting weakened the last septa of the same radius of curvature by a factor of about 2.5 relative to the tensile stresses in a sphere of nacre, (2) septa with ammonitic sutures were stronger than those with goniatitic sutures of the same thickness, and (3) septa with more “complex” ammonitic sutures were stronger at the edge between lobes and saddles than “simple” ones. These results contradict recent claims that ammonoid septa became weaker as sutural complexity increased from goniatitic through ammonitic, so that the most complex sutures were limited to the shallowest habitats. The smaller marginal flutes of complex septa were relatively strong, allowing them to be thinner than the central septum and still act as elastic wall supports. Many Mesozoic ammonoids with highly sinuous sutures occurred in deep epeiric and open-ocean habitats, whereas it is those with secondarily reduced, ceratitic sutures that were typically associated with restricted shallow basins.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".