Bibliographic record
Abstract
The potential bioavailability of phenanthrene aged in soil was determined by using a self-dying reporter bacterium, and the results were compared to two physicochemical measures, Tenax TA(®) bead-assisted desorption, and hydroxypropyl-β-cyclodextrin (HPCD) extraction. The reporter bacterium, capable of degrading phenanthrene as a sole carbon and energy source, was genetically reconstructed to die when it degrades phenanthrene. Therefore, population change of the reporter cells can be viewed as the quantification of bioavailable phenanthrene. When Ottawa sand was used as an aging matrix, the amounts of bioavailable phenanthrene (i.e. little gradual decrease) were similar, regardless of aging time, and consistent between the reporter bacterium and the two physicochemical measures. However, decrease in bioavailable phenanthrene with aging was readily evident in sandy loam with organic matter of 11.5%, with all three measures. More importantly, when the reporter bacterium was used, a rapid and significant decrease in the bioavailable fraction from 1.00 to 0.0431 was observed. The extent of decrease in bioavailable fraction was less than 40% in the two physicochemical measures, but was nearly 100% in the reporter bacterium, during the first 3 months of aging. Our results suggest that the phenanthrene fraction available to bacterial degradation, and probably the fraction that really manifests toxicity, may be much smaller than the fractions predicted with the physicochemical measures.
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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 | 0.001 | 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) | 0.001 | 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 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".