Variations on a theme of gravity coring: K-B, Glew and TechOps corers with core extrusion and high-resolution vertical sectioning of shallow aquatic sediments
Bibliographic record
Abstract
The goals of gravity coring for environmental limnological studies are to obtain an undisturbed sample of bottom sediments, preserve the sediment-water interface, maintain the original water content, and maintain the original vertical distributions of chemical, mineralogical, and biological constituents. Gravity coring devices are designed to drive core tubes or cylinders vertically into the sediments and withdraw them back to surface intact. Examples of open-barrel or gravity corers that are used within the Northern Canada Division of the Geological Survey of Canada are a modified Kajak-Brinkhurst (K-B) corer, Glew (and modified Glew) corers, and TechOps corer. Although the principles of operation are similar, each device has advantages and disadvantages that should be taken into consideration for the requirements of each specific lake sediment study. Shallow lake cores ( ?1m) taken by gravity coring methods typically require extrusion and sectioning on-site because of the high water content and likelihood of core disturbance during handling and transport. Zorbitrol (a water binding agent) can fix most gravity cores sufficiently to enable gentle transport back to the laboratory; however, it is a source of contamination that would preclude any subsequent geochemical analyses. For high water content cores, vertical extruders are the most effective. There are three components to vertical core extrusion and sectioning: maintenance of the core in a vertical position, advancement of the core material through the core tube so that sections can be expelled, and removal of the extruded section that can be transferred to sample containers. Three examples of vertical core extruding and sectioning devices portable for field use are available: one designed for use with the K-B corer with fixed interval sections and two for which the operator can define the sectioning intervals.
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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 | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.010 | 0.008 |
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".