Temporal, population, and sexual variation in hematocrit of free-living desert tortoises: correlational tests of causal hypotheses
Bibliographic record
Abstract
Hematocrit (packed cell volume, PCV) varies seasonally in some vertebrates and often differs between the sexes and among conspecific populations. Such variation in PCV may reflect variation in nutritional health, requirements for oxygen transport (metabolic rate), or hydration. The relative importance of these influences was tested with serial measurements of PCV in two Mojave Desert populations of the desert tortoise (Gopherus agassizii) over two activity seasons, during a period with large seasonal differences in availability of food and water. Hematocrit varied widely (range = 1440, CV = 20%), reflecting differences between populations, between sexes, between years, and over time within years. Causal hypotheses were tested by correlating PCV with physiological indicators of nutritional health (blood urea nitrogen), oxygen requirements (field metabolic rate), and hydration (length-relative mass, water-influx rate, urine osmolality, plasma sodium, and plasma osmolality). Results indicated a dominant influence of dehydration-induced hemoconcentration during this extreme drought period, although all correlations were relatively weak. Circumstantial evidence is marshalled to suggest longer term effects of nutrition (at seasonal, yearly, and population levels of variation) and perhaps oxygen requirements (driving sexual dimorphism). All these simultaneous and sometimes opposing effects interact in complex ways to produce the patterns of variation observed, and these interactions render PCV a poor indicator of physiological state in desert tortoises.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 teacher head, 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".