Interaction between organ mass and citrate synthase activity as an indicator of tissue maximal oxidative capacity in breeding European Starlings: implications for metabolic rate and organ mass relationships
Bibliographic record
Abstract
Summary Numerous studies have suggested that basal metabolic rate (BMR) is related to variation in mass of specific ‘energy‐expensive’ organs such as heart and kidney. However, there are inconsistencies among studies with regard to those organs that show positive relationships with BMR, potentially because such studies assume constant organ metabolic intensity or capacity (e.g. oxidative activity). This paper investigates metabolic adjustments (citrate synthase activity) in four key organs (pectoral muscle, heart, kidney and liver) in free‐living reproductive female European Starlings (Sturnus vulgaris) throughout the breeding season to determine if the cost of egg production results in readjustments in organ mass‐specific enzyme activity. Citrate synthase (CS) activity varied in relation to breeding stage and/or year, but this variation was not consistent among different organs. For some organs, total enzymatic activity was directly related to changes in organ mass in relation to breeding stage. For others, increased organ mass was associated with a decrease in mass‐specific CS activity, resulting in no net change in total organ oxidative capacity among breeding stages. Even though the liver is actively involved in yolk precursor production during egg formation, no evidence was found for up‐regulation of mass‐specific oxidative enzyme activity in this organ. Metabolic adjustments at the organ level may occur independently from organ mass changes and this confounding effect may be responsible for part of the inconsistencies found between previous studies in terms of organs mass–RMR relationships.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 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".