Swimming in the Intermediate Reynolds Range: Kinematics of the Pteropod Limacina helicina
Bibliographic record
Abstract
Limacina helicina (1-3 mm) lives in the environment that straddles both inertial and viscous regimes. In this intermediate Reynolds range (10(0)-10(3)), an oscillating appendage may use either drag-based or lift-based locomotion. The swimming motion of L. helicina was investigated to determine its mechanics and whether features of rowing or flying gaits were present. Mean speeds, stroke frequencies, and general paths were revealed from the trajectories of free-swimming individuals. High-speed videography of tethered animals enabled a detailed analysis of stroke parameters involved in L. helicina swimming. During swimming episodes, L. helicina ascend along a sawtooth trajectory in mostly linear and sometimes helical paths. Mean speeds varied from 13 to 44 mm/s for straight ascents and slightly more for helical paths. During swimming, the stroke cycle caused oscillations in body orientation, whereas sinking is characterized by smooth straight descents. Sinking speeds of 5-45 mm s(-1) were observed. Wing-beat frequencies decreased with body size from 4.5 to 9.4 Hz. The wing stroke is a complex, three-dimensional motion that does not perfectly correspond to theoretical concepts of drag-based or lift-based propulsion. Instead, the repertoire of movements indicates that elements of both rowing and flying are incorporated in the swimming of L. helicina with the added element of rotation. Size-dependent differences in stroke mechanics are described. Of particular note is evidence that a clap-and-fling mechanism is applied during the stroke cycle.
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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".