Ubiquity of anomalous fading in K-feldspars and the measurement and correction for it in optical dating
Bibliographic record
Abstract
Anomalous-fading rates were measured in K-feldspars separated from 49 sediment samples, mainly from North America. The intensity of the optically stimulated luminescence was found to decrease linearly with the logarithm of time since irradiation between 2 days and ~1 year of storage at room temperature. Anomalous-fading rates ranged from 2% to 10% per decade, a decade being a factor of 10 in time since irradiation. The sample provenances were sufficiently varied that anomalous fading appears to be ubiquitous. We have experimented with correction of optical ages for anomalous fading on the assumption that the observed fading can be extrapolated a further four decades in time. The corrected ages are in satisfactory agreement with independent ages. These results are restricted to the low-dose region of the dose response and are not expected to be applicable to samples older than ~2050 ka.
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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 | 0.005 | 0.015 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".