Does Metamorphosis Increase the Susceptibility of Frogs to Highly Hydrophobic Contaminants?
Bibliographic record
Abstract
The purpose of this study was to determine whether the process of metamorphosis in amphibians increases the chemical activity of hydrophobic contaminants such as polychlorinated biphenyls (PCBs). We conducted an experiment in which green frog tadpoles were orally dosed with a PCB mixture; then placed into clean water to eliminate the chemicals as metamorphosis occurred. On several sampling dates before and during metamorphosis, organisms were sacrificed and analyzed to determine lipid contents and concentrations of individual PCB congeners. The majority of the PCBs studied in this experiment showed increases in chemical activity (fugacity) as a result of the physical changes that occurred during amphibian metamorphosis. A positive relationship was observed between PCB hydrophobicity and the magnitude of the fugacity increase. We determined that the fugacity of a persistent PCB congener will increase during green frog metamorphosis if its log K(ow) value is greater than 5.85. The fugacity of some of the more highly hydrophobic PCBs increased during metamorphosis by up to a factor of 4. Because of the rapid increases in chemical activity that were observed during metamorphosis, we conclude that toxicity tests involving hydrophobic organic contaminants should be conducted not only on tadpoles or adult frogs, but also on metamorphosing amphibians.
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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".