Pleistocene Hairs: Microscopic Examination Prior to Destructive Analysis
Bibliographic record
Abstract
Pleistocene hairs can provide significant insights into the peopling of the Americas through isotopic and genetic analysis. Microscopic identification of isolated hairs in coprolites or sediments typically exposes hairs to mounting and/or casting media that might alter stable isotope, radiocarbon, trace element, and ancient DNA results. This paper tests the effects of such contaminants on stable carbon and nitrogen isotope analyses of hair, and describes alternative methods for preliminary hair examination. Contaminant-free methods can be used to identify growth phases, orient hairs, match broken hair fragments, identify unusual hairs for further analysis (e.g., isolated human hairs among predominantly animal remains), and preliminarily identify hairs to genus or species. This paper compares a reference collection of megafauna hairs, including mammoth (Mammuthus spp.), horse (Equus spp.), ground sloth (Nothrotheriops shastensis), and bison (Bison spp.) with isolated hairs from the late Pleistocene Colorado Plateau. Isolated hairs were attributed to mammoth, bison, and human.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".