Preparing for Migration? The Effects of Photoperiod and Exercise on Muscle Oxidative Enzymes, Lipid Transporters, and Phospholipids in White‐Crowned Sparrows
Bibliographic record
Abstract
The extreme energetic demands of avian migration result in various physiological changes that can be observed during the migratory period. However, the degree to which birds alter muscle physiology in advance of migration has been poorly studied. We studied the effects of "migratory" photoperiod and exercise on metabolic enzymes, fatty acid transporter mRNA expression, and muscle phospholipid fatty acid composition in captive white-crowned sparrows (Zonotrichia leucophrys). Ten sparrows were held on short photoperiod (8L:16D) for 58 d then switched to long days (16L:8D) for 3 wk before sampling. Increased nightly activity indicated that the birds were indeed in migratory condition. Another 13 birds were held on short days during the entire experiment, and a subset (5) were exercised for 1 h every other day for the last 2 wk. "Migratory" photoperiod did not change the activities of citrate synthase, carnitine palmitoyl transferase, and 3-hydroxyacyl-CoA dehydrogenase or the expression of FAT/CD36, FABPpm, and H-FABP mRNA in pectoralis muscle, suggesting that these cannot be increased in advance of migratory flight. Docosahexaenoic acid increased in pectoralis muscle phospholipids with exercise but was negatively correlated with catabolic enzyme activity, indicating that the presence of this fatty acid may not aid migratory performance as suggested by other studies.
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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 | 0.000 | 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) | 0.001 | 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".