The relationship of vascular anatomy to thermal physiology: linking anatomical and imaging studies to <i>in vivo</i> non‐invasive infrared thermography of free‐ranging birds
Bibliographic record
Abstract
Vertebrates use the blood vascular system to moderate the temperature of specific anatomical regions. However, in many groups, such as birds, fundamental thermoregulatory mechanisms—the actual link between physiological function (heating and cooling) and the underlying vascular “plumbing”—have largely remained obscure, challenging our understanding of issues ranging from organismal responses to climate change to the human health consequences of vascular disease. In vivo physiological testing typically involves highly invasive procedures that may impose confounding artifacts due to stress responses mediated by the sympathetic nervous system. Fortunately, high‐resolution infrared (IR) thermal imaging provides a non‐invasive means of in vivo physiological measurement of surface temperatures in free‐ranging, normally behaving animals. In our study, thermal imaging was used to document heat maps of freely ranging birds (e.g., vultures, pelicans) in South Carolina and Florida. Quantitative thermographic data were analyzed to assess sites of heat exchange. Thermal data were compared to existing and new anatomical data based on microCT scanning of radio‐opaque (barium‐latex) vascular injections on legally obtained cadaveric bird specimens. Specific regions of the head where vascular devices in birds are suspected to be important for shedding heat as well as for cooling venous blood destined for the brain and eye were analyzed for anatomical and physiological correlations. This study seeks to establish the mechanistic links that ultimately allow birds to manage thermal stressors. Thermal images of investigated sites of thermal exchange indicated heat flow was found to correspond to the location of known blood vessels. These blood vessels were discernable in times of both heating and cooling. For example, in pelicans, the location of the ophthalmic rete corresponds to the location of a cool spot located behind the eye. Blood vessels in the pelican's pouch correspond to a streak of high temperature in the pouch. These results indicate that blood vessels play an active role in the thermophysiology of free‐ranging and unstressed birds and that the details of thermoregulatory mechanisms are discernable with non‐invasive methods. Support or Funding Information United States National Science Foundation (IOB‐0517257, IOS‐1050154), Ohio University Heritage College of Osteopathic Medicine, Ohio University Research Committee, Natural Sciences and Engineering Research Council of Canada, and the National Geographic Society. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".