Characterization of diurnal urea excretion in the mangrove killifish,<i>Rivulus marmoratus</i>
Bibliographic record
Abstract
An unusual characteristic of nitrogen excretion in the ammoniotelic mangrove killifish Rivulus marmoratus is that urea is excreted (J(urea)) in a distinct diurnal pattern, whereas ammonia is excreted (J(amm)) at a steady rate. In this study we tested the hypothesis that the diurnal pattern in R. marmoratus is an endogenously generated pattern that is characterized as a circadian rhythm. This hypothesis was tested by measuring J(urea) and J(amm) following manipulation of feeding or lighting regimes. The diurnal J(urea) pattern in food-deprived R. marmoratus had a 24 h periodicity under normal conditions of 12 h:12 h light:dark (12:12 L:D) with 72% more urea excreted during 12:00 h and 18:00 h. In contrast, there was no significant pattern in J(amm). Fed fish (12:12 L:D) demonstrated a diurnal pattern in both J(urea) and J(amm) with up to an eightfold increase in excretion rates compared with rates obtained from food-deprived fish. Patterns of J(urea) were free running with a 24 h period under conditions of continuous darkness (0:24 L:D). Exposure to an inverse photoperiod (12:12 D:L) resulted in entrainment of the J(urea) pattern to the new photoperiod, with the highest rates of excretion occurring during midday of the new photoperiod. In contrast to R. marmoratus, nitrogen excretion rates in the zebrafish Danio rerio remained constant over time. The results of this study show that J(urea) in R. marmoratus demonstrates the characteristics of a circadian rhythm: a 24 h periodicity, a free-running rhythm in continuous conditions, and entrainment to new photoperiods.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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) | 0.000 | 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".