Different radial growth responses to climate warming by two dominant tree species at their upper altitudinal limit on Changbai Mountain
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Pinus koraiensis
Growing season
To study the effect of altitudes on the photosynthate accumulation and distribution pattern of Angelic sinensis in Gansu province and provide theontical for its expanding ecological planting region.Used field test to study the photosynthate accumulation and distribution pattern of Angelic sinensis on three different altitudinal gradients from 2 300 m to 2 800 m.Before September 25, total photosynthate accumulation were decreased with the increasing of elevation, which amaunt was 176 g/plant, 166 g/plant and 128 g/plant, respectively. The total photosynthate of low-altitude and middle-altitude were significantly higher than that of high-altitude (P < 0.05). After September 25, middle-altitude was significantly higher than the other two altitudes (P < 0.05), respectively, by 13.9% and 11.1%. The photosynthate accumulation rate existed the altitude effects, there was no significant difference between high-altitude (46.7%) and middle-altitude (43.7%), but they were even significantly higher than that of low-altitude (33.1%). The root distribution proportion (> 30%) existed the difference, that of high-altitude was 10 days earlier than the other two altitudes, and later that of high-altitude (about 54%) was higher than the other two altitudes (49.8% - 50.9%), it laid the foundation for yield formation. Yield of Angelic sinensis was as follows: middle-altitude (28.4 g/ plant), high-altitude (26.6 g/plant) and low-altitude (21.8 g/plant). Yield of Angelic sinensis middle-altitude and high-altitude were higher than that of low-altitude, respectively, by 30.2% and 22.2%, and it had a significant difference (P < 0.05), this result was consistent with the photosynthate accumulation rate.Altitudinal gradients affect yield formation of Angelic sinensis by changing the photosynthate distribution pattern and dry matter accumulation rate. So by appropriately increasing altitude, the root distribution proportion and yield are improved, this provides theoretical reference for expanding Angelic sinensis planting ecological region.
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A striking feature in the acclimatization of man to high altitude is the great variability in the responses of different individuals to the lowered air pressure. This has been observed repeatedly by mountaineers and was very evident during the work of the International High Altitude Expedition to Chile in 1935. Our experience was in agreement with other reports: (1) individuals of similar age and general physical condition differ widely in their ability to adjust to high altitude; (2) the differences between individuals become increasingly marked at successively higher altitudes; (3) the initial response to the high altitude is not always a good indication of the eventual acclimatization to be reached; (4) good acclimatization to a moderately high altitude is not necessarily an indication that relatively good acclimatization will be attained at very high altitudes.
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The 5000m altitude of the potential site for the Millimeter Array (MMA) in Northern Chile is so high that high-altitude problems for both the staff and equipment must be considered and included in planing for the facility. The very good accessibility of the site, only one hour's drive from the nearest town at altitude 2440m, makes it possible for MMA workers to sleep and perform much of their work at low altitude. Workers on the site will have 11 percent less oxygen available than workers at Mauna Kea Observatory. It is expected that the mental abilities and ability to do hard physical labor of workers on the high site will be reduced by 10 percent to 30 percent compared to sea-level. In-doors working areas on the MMA site will have their atmospheres oxygen enriched to provide an effective working altitude of 3500m where loss of mental ability should be small. Tests of oxygen enrichment at high-altitude Chilean mines and at the University of California White Mountain Research Station show that it is feasible and economic. Problems of equipment operation at 5000m altitude are expected to be manageable.
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The impact of high-altitude environment was studied on respiratory functions and body measurements in adolescent Bod girls of Ladakh, Jammu and Kashmir, India. Data were collected on 133 high-altitude and 141 low-altitude Bod girls in the age range 12-18 years. Lung functions were, age to age, higher in high-altitude girls than their coeval lowlanders. This has been explained as an adaptation to the stress of low atmospheric pressure at high altitude. This response is similar to the one observed in growing Bod boys living in the same area (Malik and Singh 1979, 1984). High-altitude girls were shorter and lighter, the difference was more pronounced in weight and especially after 14 years of age.
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Objective To investigate the effects of high altitude and stationed duration on blood pressure in male soldiers in Qinghai-Tibetan plateau.Methods Blood pressure of 428 male soldiers with 2,5,8 years stationed in 6 spots on Qinghai-Tibetan plateau from 3 500 meters to 4 857 meters were measured.According to three different altitudes,the subjects were involved in 3 500-4 000 meters,139 people,average age(23.0±3.6) years old;4 001-4 499 meters,133 people,average age(23.6±3.9)years old;≥4 500 meters,156 people,average age(22.5±2.6) years old.Blood pressure,prevalence of high altitude hypotension and hypertension were compared.Results Compared with 3 500-4 000 meters,the prevalence of high altitude hypertension significantly increased in the groups with altitude from 4 001-4 499 meters and above 4 500 meters(18.8% vs 15.4% vs 7.9%,both P0.05),and compared with 4 001-4 499 meters,the prevalence of high altitude hypotension significantly increased in the group with altitude above 4 500 meters(16.0% vs 5.8%,P0.05).Compared with the groups whose durations were up to 2,8 years,the prevalence of high altitude hypertension significantly increased in the group with the duration of 5 years(8.6%,12.6% vs 24.4%,both P0.05).Meanwhile,compared with the group whose duration was up to 2 years,the prevalence of high altitude hypotension significantly increased in the group with duration of 5 years(18.7% vs 6.7%,P0.05).Conclusion High altitude and stationed duration of 5 years are important factors to high altitude hypotension and hypertension with male soldiers,the male soldiers with those factors are the focus of people to prevent and control high altitude hypotension and hypertension in Qinghai-Tibetan plateau.
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Elevation (ballistics)
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Background : Hemoglobin is the iron holding and oxygen carrying protein found inside the red blood cells. Studies have been done on Hb level variations in gender, race and region but no comparative study on different altitude effects in Pakistan is reported. Comparison of Hemoglobin level between people living at high altitude and low altitude was done in this study. Samples from district Skardu Gilgit-Baltistan, Pakistan were used as high-altitude samples and samples from district Lahore, Pakistan were utilized as low altitude samples. Samples were obtained from those people who don’t have any haemoglobinopathies. Methods: 50 blood samples were collected for this study; 25 individuals were from low altitude level and 25 of high-altitude level. Estimation of hemoglobin concentration was done by Cyanmethemoglobin method to compare the individuals HB from low altitude with high altitude. Results: All the blood samples were properly analyzed, and the results extracted from the samples, living at low altitude were compared with those living at high altitude. Mean and standard deviation values were calculated, and they found to be different for both populations, people at high altitude and the people living at low altitude. 25 residents of high altitude showed following results of hemoglobin: mean=15.0 and SD=0.632. On the other hand, 25 individuals of low altitude revealed these results: mean=14.53 and SD=0.633. Conclusion: There was a significant difference in Hb level in blood at high altitude (7500 feet) and low altitude (711 feet from sea level) P=0.004. Keywords: Hemoglobin, Standard Deviation
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Altitude training
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That altitude produces an increase in the number of red corpuscles in the blood is a principle very generally accepted. The work of a number of investigators appears to show that the increase is directly proportional to the altitude. At sea level we have, according to Laasche, a blood count of 4,974,000 cells which is by many considered normal.† At an altitude of 9,500 feet Egger found a count of 7,000,000 cells; while Viault, who worked in the Cordilleras of South America at an altitude of 14,400 feet, found the high count of 8,000,000 cells. All these counts refer to human subjects. As a result of these and similar studies the principle of high blood counts in high altitudes is regularly found in our works on hematology, and is regularly taught in the medical schools. Further, more or less elaborate theories have been based on it to
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Human blood
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Low-pressure area
Low altitude
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The assessment of an individual's degree of acclimatization to altitude is difficult. This is particularly applicable to military operations that have to be performed at altitude. This study describes a new and simple test that allows for the determination of an individual's risk for high-altitude illness at higher altitudes. The prediction is based on the lowest oxygen saturation (SaO2) found during an uphill run at high altitude (11,060 ft [3,371 m]), combined with the time needed to complete the run. The test results were compared against the severity of high-altitude symptomatology on the summit of Mont Blanc (15,762 ft [4,808 m]). The main outcome was the significant correlation between time as well as SaO2 and the severity of high-altitude symptomatology on the summit of Mont Blanc. The newly developed performance test allows, at a "safe" altitude, the prediction of an individual's risk of developing high altitude illness if they continue to ascend. It allows the determination of the best acclimatized subjects within a group, for example, before a military mission at greater altitude.
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Altitude sickness
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