Physiological and ecological aspects of low-temperature tolerance in embryos of the wood frog, <i>Rana sylvatica</i>
Bibliographic record
Abstract
Wood frogs (Rana sylvatica) breed in late winter in temporary ponds, where eggs are deposited in communal surface rafts. Subsequently, developing embryos may face subzero temperatures. In the laboratory, individual embryos supercooled moderately (to 4.2°C for embryos in their jelly capsules; to 5.0°C for embryos removed from the jelly capsule) when chilled in the absence of external ice nuclei, but did not resist inoculative freezing when chilled in contact with external ice. They survived acute episodes (118 h) of supercooling to temperatures between ca. 0.5 and 2.0°C. Stage-12 embryos (six of six) survived freezing for 1 h at 2.0°C, but only one of six survived a 3.5-h freezing episode at the same temperature. Stage-13 and -14 embryos survived freezing episodes of 4.5 h at 1.0°C (six of six survived) and 18 h at 0.5°C (six of six survived), respectively. In the field, temperatures were monitored every 5 min for 21 d in embryo masses of wood frogs and Jefferson salamanders (Ambystoma jeffersonianum) at a breeding pond in central Kentucky. Wood frog embryos experienced higher daily maximum and lower daily minimum temperatures than salamander embryos, which were deeper in the water column. Wood frog embryos spent more time at risk of cryoinjury (i.e., at temperatures [Formula: see text]1°C), but the two species accumulated similar degree-days over the 21-d observation period. Their position in the water column may permit wood frogs to garner a developmental advantage in milder years, when daily minimum temperatures are similar between the two species. Wood frog embryos appear to offset some of the risks associated with this more exposed position by tolerating somatic freezing at high subzero temperatures.
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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) | 0.001 | 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 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".