Seasonal factors and birth weight, new evidence from the Southern Hemisphere
Bibliographic record
Abstract
Birth weight has implications for multiple psychological and physical conditions throughout life. Birth weight is known to be affected by many factors, such as gestational age, maternal nutrition, cigarette smoking, hormones, and maternal height, weight, age, and parity. An additional intriguing correlate of birth weight is season-of-birth. Existing research suggests that seasonality in birth weight from equatorial countries depends on food availability and maternal physical labor. North of the Tropic of Cancer (23.5N), higher birth weights occur in the late winter and spring, and the most prevalent explanatory hypotheses concern the influences of temperature or day length. The seasonal pattern would be expected to be offset by six months in the Southern Hemisphere, but only one study was found from south of the Tropic of Capricorn (23.5S). Thus, in this study, time series analyses of a 20-year, million-birth New Zealand sample tested the hypothesis that heavier birth weights will occur in the spring. Theresults support hypotheses that seasonally varying factors, such as temperature and day length, affect fetal growth during the gestational period, resulting in seasonal birth weight differences.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".