Use of Isotopic Analysis of Insect and Freshwater Crustacean Chitin from Quaternary Sediments for Reconstruction of Past Natural Environments
Bibliographic record
Abstract
Abstract An analysis of the isotopic composition of chitin (oxygen and nitrogen) was made for the first time for terrestrial and freshwater Pleistocene arthropods from the localities at the Old Crow River in northwestern Yukon, representing an interval from the middle Pleistocene to the Holocene. About a hundred fragments of arthropods were tested among the fossils, including the weevils Lepidophorus lineaticollis (Coleoptera, Curculionidae), some ground beetles (Coleoptera, Carabidae), as well as the ephippia of freshwater crustacean Daphnia cf. pulex (Branchiopoda, Daphniidae). An isotope analysis of extant representatives of the same arthropods from different regions of the Yukon was made for comparison. Isotopic lines show differences between terrestrial and freshwater animals. The isotopic composition of freshwater crustaceans shows the difference between cold and warm time intervals. Herbivorous beetles show a more complex picture, possibly associated with the adaptation to different biotopes and host plants, which allowed the species to survive during climatic and environmental fluctuations.
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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 | 0.002 | 0.001 |
| 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".