Bone mineral acquisition during childhood and adolescence: physical exercise as a preventative measure
Bibliographic record
Abstract
Introduction The history of the human species has always included a lifestyle demanding heavy and prolonged physical work that was necessary for survival (Bortz, 1985). It has been estimated that the skeletal mass of humans living in the Late Paleolithic era exceeded that of humans in subsequent civilizations (Larsen, 1987; Wolpoff, 1980). This is attributed, in part, to the heavy physical exertion required for subsistence at that time (Eaton et al., 1988). Times, however, have changed and conditions of disuse have become firmly entrenched in our medical vocabulary. It has been suggested that the ability of bone to adapt to mechanical loading is much greater in the immature, as compared to the mature, skeleton (Parfitt, 1994). Osteoporosis prevention, therefore, may begin early in life when optimal bone mineral accretion is critical to the attainment of a healthy adult skeleton (Bailey & McCulloch, 1992; Fassler & Bonjour, 1996; Parfitt, 1994). Peak bone mass is a major determinant of adult bone mass which is, in turn, related to fracture risk (Matkovic et al., 1979). Upwards of 90% of adult bone mass is achieved by the end of adolescence and subsequent gains are relatively small (Bonjour et al., 1991; Glastre et al., 1990; Slemenda et al., 1994; Theintz et al., 1992).
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".