The calculated parameters for the ROC curves of detection of vasodilatation (figure 2-b) applying the proposed method on the testing dataset.

*<p>Area under the ROC curve.</p>**<p>95% confidence interval.</p>x<p>Partial area under the ROC curve for .</p>xx<p>Value of FPR when .</p

A representative intracranial pulse with its identified peaks and troughs.

<p>A representative intracranial pulse with its identified peaks and troughs.</p

Correlation analysis of the proposed vasoreactivity indices and the level of change of P_ETCO2 (); (a) calculated vasodilatation index (VDI) over for all 27 subjects during baseline and CO₂ rebreathing measurement; (b) calculated vasoconstriction index (VCI) over for all 27 subjects during baseline and hyperventilation measurement.

<p>Correlation analysis of the proposed vasoreactivity indices and the level of change of P_ETCO2 (); (a) calculated vasodilatation index (VDI) over for all 27 subjects during baseline and CO₂ rebreathing measurement; (b) calculated vasoconstriction index (VCI) over for all 27 subjects during baseline and hyperventilation measurement.</p

The effect of training dataset on the detection of vasoreactivity; (a) accuracy of the detection of vasodilatation and vasoconstriction for different number of subjects in the training dataset; (b) The size (number of consistent MOCAIP metrics) of the largest template obtained from a training dataset of n-subject where n = 1,…,21.

<p>The effect of training dataset on the detection of vasoreactivity; (a) accuracy of the detection of vasodilatation and vasoconstriction for different number of subjects in the training dataset; (b) The size (number of consistent MOCAIP metrics) of the largest template obtained from a training dataset of n-subject where n = 1,…,21.</p

The calculated parameters for the ROC curves of detection of vasoconstriction (figure 3-b) applying the proposed method on the testing dataset.

*<p>Area under the ROC curve.</p>**<p>95% confidence interval.</p>x<p>Partial area under the ROC curve for .</p>xx<p>Value of FPR when .</p

Comparison of vasoreactivity detection performance using the proposed vasoreactivity indices and two other conventional hemodynamic metrics; resistance area product (RAP) and critical closing pressure (CCP); (a) vasodilatation; (b) vasoconstriction.

<p>Comparison of vasoreactivity detection performance using the proposed vasoreactivity indices and two other conventional hemodynamic metrics; resistance area product (RAP) and critical closing pressure (CCP); (a) vasodilatation; (b) vasoconstriction.</p

The description of 128 metrics derived from the six landmarks detected by MOCAIP algorithm on a pulse of CBFV (The zero of time axis refers to the timing of R component of electrocardiograph QRS).

<p>The 28 metrics belonging to group indices of 1 to 8 are called basic metrics, while the remaining 100 metrics (belonging to group indices of 9 to 12 ) are extended metrics calculated as ratios among basic metrics within each group.</p

Examples of invalid data segments during CO₂ rebreathing and hyperventilation; (a) non-increasing trend of P_ETCO2 for subject #4 during CO₂ rebreathing; (b) non-decreasing trend of P_ETCO2 for subject #3 during hyperventilation; (c) non-decreasing trend of cerebrovascular resistance index (CVRi) for subject #4 during CO₂ rebreathing; (d) non-increasing trend of CVRi for subject #3 during hyperventilation.

<p>Examples of invalid data segments during CO₂ rebreathing and hyperventilation; (a) non-increasing trend of P_ETCO2 for subject #4 during CO₂ rebreathing; (b) non-decreasing trend of P_ETCO2 for subject #3 during hyperventilation; (c) non-decreasing trend of cerebrovascular resistance index (CVRi) for subject #4 during CO₂ rebreathing; (d) non-increasing trend of CVRi for subject #3 during hyperventilation.</p

Correlation analysis of the proposed vasoreactivity indices and cerebrovascular resistance index change (); (a) calculated vasodilatation index (VDI) over during CO2 rebreathing; (b) calculated vasoconstriction index (VCI) over during hyperventilation.

<p>Correlation analysis of the proposed vasoreactivity indices and cerebrovascular resistance index change (); (a) calculated vasodilatation index (VDI) over during CO2 rebreathing; (b) calculated vasoconstriction index (VCI) over during hyperventilation.</p

AltitudeOmics: Rapid Hemoglobin Mass Alterations with Early Acclimatization to and De-Acclimatization from 5260 m in Healthy Humans

<div><p>It is classically thought that increases in hemoglobin mass (Hbmass) take several weeks to develop upon ascent to high altitude and are lost gradually following descent. However, the early time course of these erythropoietic adaptations has not been thoroughly investigated and data are lacking at elevations greater than 5000 m, where the hypoxic stimulus is dramatically increased. As part of the AltitudeOmics project, we examined Hbmass in healthy men and women at sea level (SL) and 5260 m following 1, 7, and 16 days of high altitude exposure (ALT1/ALT7/ALT16). Subjects were also studied upon return to 5260 m following descent to 1525 m for either 7 or 21 days. Compared to SL, absolute Hbmass was not different at ALT1 but increased by 3.7±5.8% (mean ± SD; n = 20; p<0.01) at ALT7 and 7.6±6.6% (n = 21; p<0.001) at ALT16. Following descent to 1525 m, Hbmass was reduced compared to ALT16 (−6.0±3.7%; n = 20; p = 0.001) and not different compared to SL, with no difference in the loss in Hbmass between groups that descended for 7 (−6.3±3.0%; n = 13) versus 21 days (−5.7±5.0; n = 7). The loss in Hbmass following 7 days at 1525 m was correlated with an increase in serum ferritin (r = −0.64; n = 13; p<0.05), suggesting increased red blood cell destruction. Our novel findings demonstrate that Hbmass increases within 7 days of ascent to 5260 m but that the altitude-induced Hbmass adaptation is lost within 7 days of descent to 1525 m. The rapid time course of these adaptations contrasts with the classical dogma, suggesting the need to further examine mechanisms responsible for Hbmass adaptations in response to severe hypoxia.</p></div