Journal of Biometrics & Biostatistics

Otto Appenzeller

Publications

• Research Article
  Human and Hummingbird Hemoglobin Concentrations and MetabolicRhythms at Altitude Determined with Statistical Modeling
  Author(s): Clifford Qualls, Christopher C Witt, Nicholas R Wilson, Sebastian Restrepo Cruz, Emil Bautista and Otto AppenzellerClifford Qualls, Christopher C Witt, Nicholas R Wilson, Sebastian Restrepo Cruz, Emil Bautista and Otto Appenzeller
  
  Hummingbirds show remarkable adaptation to high altitude hypoxia whereas humans are imperfectly adapted to high altitude living. Here we compare hemoglobin levels and metabolism derived from growth rhythms in hummingbirds and humans. To compare growth rhythms, we analyzed growth intervals in hummingbird tail feathers and human growing tissues such as hair. We find that hemoglobin levels were higher in hummingbirds (P<0.001) than in humans, but the influence of altitude on hemoglobin was more pronounced in humans (slope, steeper with increasing altitude, P<0.001), and levels for both taxa converge at extreme elevations. The power spectra from growth intervals in growing tissues which reflect metabolism in both species, were not different (low frequency/high frequency ratios (LF/HF) in the two species) P>0.22 NS. In a comparison among hummingbird.. Read More»
  DOI: 10.4172/2155-6180.1000373

  Abstract PDF