the mean fiber length of three beech trees (fagus orientalis l.) at the lower and higher points (1% and 75% tree height) of the stem at an intermediate altitude (500-1000m) in the caspian forests in sari region were 1.36 and 1.22mm respectively, close to the values in three trees at high altitude (1000-1500m), that were found to be 1.39 and 1.36 mm. the mean fiber lengths of the whole stem, usi...

BACKGROUND A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Fur...

INTRODUCTION This study aimed to evaluate the retinal changes associated with altitude illness in young soldiers. METHODS A total of 50 young soldiers with altitude illness, who were referred to a tertiary care hospital between October 2003 and January 2006, were included in the study. RESULTS All the soldiers were male. The mean age of the subjects was 30.3 (range 20-44) years. Nine (18 pe...

In high-altitude climbers, the kidneys play a crucial role in acclimatization and in mountain sickness syndromes [acute mountain sickness (AMS), high-altitude cerebral edema, high-altitude pulmonary edema] through their roles in regulating body fluids, electrolyte and acid-base homeostasis. Here, we discuss renal responses to several high-altitude-related stresses, including changes in systemic...

Altitude illness affects 25 to 85 percent of travelers to high altitudes, depending on their rate of ascent, home altitude, individual susceptibility, and other risk factors. Acute mountain sickness is the most common presentation of altitude illness and typically causes headache and malaise within six to 12 hours of gaining altitude. It may progress to high-altitude cerebral edema in some pers...

Hemodialysis patients who live at high altitude use less exogenous erythropoietin but achieve higher hematocrit levels than those living at a lower altitude. The authors hypothesized that the effect of altitude would be strongest in hemodialysis patients with poor anemia treatment response. To explore this hypothesis, they studied anemia-related outcomes in US hemodialysis patients who move to ...

PURPOSE This study aimed to quantify the pupillary light reaction during high altitude exposure using the state of the art Compact Integrated Pupillograph (CIP) and to investigate a potential correlation of altered pupil reaction with severity of acute mountain sickness (AMS). This work is related to the Tübingen High Altitude Ophthalmology (THAO) study. METHODS Parameters of pupil dynamics (...

This paper introduces Modified Altitudeand DiveGuidance laws for escaping a microburst with turbulence. First, a new safety metric is constructed that quantifies the aircraft upward force capability in a microburst encounter. In the absence of turbulence, the safety factor is shown to be a decreasing function of altitude. This suggests that descending to a low altitude may improve safety in the...

Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-fr...

introduction: extreme altitude travel has gained popularity globally for adventurous, scientific, and military endeavors. cerebral venous sinus thrombosis (cvst) at extreme altitude is a rare, covert, and emergent condition requiring immediate intervention. case presentation: a case of cvst masqueraded as high altitude cerebral edema (hace) at 6700 m/22000 ft in karakoram himalayas. atypical ol...