The sublethal effects of 2,4-D dimethylamine on wood frog tadpoles in Saskatchewan
Bibliographic record
Abstract
Declining amphibian populations in association with an incidence of deformities have been observed globally.These observations have alarmed the scientific community as well as the general public.Potential causes include exposure to pesticides; therefore two experiments were performed to test the sublethal effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on tadpoles of the wood frog (Rana sylvatica).Wood frog tadpoles in the first experiment were exposed to 2,4-D amine at 0.1, 1.0 and 100 g/L in outdoor microcosms.Morphometric measures (total length, snout-vent length (SVL) and wet weight) were taken at metamorphic climax.Deformities and circulating hormone concentrations (corticosterone -CORT) were also assessed.Results showed that though tadpoles were exposed to various concentrations of 2,4-D throughout their aquatic life, there were no treatment differences associated with any of the endpoints except for total length (p = 0.023).Total length during metamorphosis was highly variable.Although statistically significant, biological significance was questionable.The second experiment was conducted in the field using natural ponds.The experimental groups included forested ponds (removed from pesticide exposure), agricultural ponds (potentially exposed) and treated agricultural ponds (intentionally treated with 2,4-D to achieve a concentration of 10 g/L).Relatively rapid degradation of 2,4-D occurred in all treated ponds.The mean half-life was 8.0 + 5.5 days.In spite of the degradation, 2,4-D was present in the ponds until tadpoles metamorphosed.Similar endpoints including morphometric measures, as well as deformities and plasma CORT hormone were determined.In addition, total lipid and total protein (of the carcass) were also measured.Unlike the microcosm study, statistically significant differences were observed in SVL, wet weight and total protein although the differences may have been unrelated to 2,4-D exposure.The metamorphs sampled from the forested ponds were smaller in
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".