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high altitude

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    We tested the hypothesis that the individual ventilatory adaptation to high altitude (HA, 5050 m) may influence renal water excretion in response to water loading. In 8 healthy humans (33+/-4 S.D. years) we studied, at sea level (SL) and at HA, resting ventilation (VE), arterial oxygen saturation (SpO2), urinary output after water loading (WL, 20 mL/kg), and total body water (TBW). Ventilatory response to HA was defined as the difference in resting VE over SpO2 (DeltaVE/DeltaSpO2) from SL to HA. At HA, a significant increase in urinary volume after the first hour from WL (%WLt0-60) was observed. Significant correlations were found between DeltaVE/DeltaSpO2 versus %WLt0-60 at HA and versus changes in TBW, from SL to HA. In conclusion, in healthy subjects the ventilatory response to HA influences water balance and correlates with kidney response to WL. A higher ventilatory response at HA, allowing a more efficient water renal handling, is likely to be a protective mechanisms from altitude illness.

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    Yoga-derived breathing has been reported to improve gas exchange in patients with chronic heart failure and in participants exposed to high-altitude hypoxia. We investigated the tolerability and effect of yoga breathing on ventilatory pattern and oxygenation in patients with chronic obstructive pulmonary disease (COPD). METHODS: Patients with COPD (N = 11, 3 women) without previous yoga practice and taking only short-acting ß2-adrenergic blocking drugs were enrolled. Ventilatory pattern and oxygen saturation were monitored by means of inductive plethysmography during 30-minute spontaneous breathing at rest (sb) and during a 30-minute yoga lesson (y). During the yoga lesson, the patients were requested to mobilize in sequence the diaphragm, lower chest, and upper chest adopting a slower and deeper breathing. We evaluated oxygen saturation (SaO2%), tidal volume (VT), minute ventilation (E), respiratory rate (i>f), inspiratory time, total breath time, fractional inspiratory time, an index of thoracoabdominal coordination, and an index of rapid shallow breathing. Changes in dyspnea during the yoga lesson were assessed with the Borg scale.

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    Assessment of the presence and severity of acute mountain sickness (AMS) is based on subjective reporting of the sensation of symptoms. The Lake Louise symptom scoring system (LLS) uses categorical variables to rate the intensity of AMS-related symptoms (headache, gastrointestinal distress, dizziness, fatigue, sleep quality) on 4-point ordinal scales; the sum of the answers is the LLS self-score (range 0–15). Recent publications indicate a potential for a visual analogue scale (VAS) to quantify AMS. We tested the hypothesis that overall and single-item VAS and LLS scores scale linearly. We asked 14 unacclimatized male subjects [age 41 (14), mean (SD) yr; height 176 (3)?cm; weight 75 (9)?kg] who spent 2 days at 3647?m and 4 days at 4560?m to fill out LLS questionnaires, with a VAS for each item (i) and a VAS for the overall (o) sensation of AMS, twice a day (n?=?172). Even though correlated (r?=?0.84), the relationship between LLS(o) and VAS(o) was distorted, showing a threshold effect for LLS(o) scores below 5, with most VAS(o) scores on one side of the identity line. Similar threshold effects were seen for the LLS(i) and VAS(i) scores. These findings indicate nonlinear scaling characteristics that render difficult a direct comparison of studies done with either VAS or LLS alone

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    The Himalayan-Karakoram range - for its elevation and geographic location, represents one of the ideal places for studying long-range pollutant transport systems on a regional scale and for monitoring changes index by mechanisms that act on global scale through monsoon circulation. This book offers a comprehension of the environmental phenomena

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    Peribronchial edema has been proposed as a mechanism enhancing airway responses to constrictor stimuli. Acute exposure to altitude in nonacclimatized lowlanders leads to subclinical interstitial pulmonary edema that lasts for several days after ascent, as suggested by changes in lung mechanics. We, therefore, investigated whether changes in lung mechanics consistent with fluid accumulation at high altitude within the lungs are associated with changes in airway responses to methacholine or exercise. Fourteen healthy subjects were studied at 4,559 and at 120 m above sea level. At high altitude, both static and dynamic lung compliances and respiratory reactance at 5 Hz significantly decreased, suggestive of interstitial pulmonary edema. Resting minute ventilation significantly increased by ?30%. Compared with sea level, inhalation of methacholine at high altitude caused a similar reduction of partial forced expiratory flow but less reduction of maximal forced expiratory flow, less increments of pulmonary resistance and respiratory resistance at 5 Hz, and similar effects of deep breath on pulmonary and respiratory resistance. During maximal incremental exercise at high altitude, partial forced expiratory flow gradually increased with the increase in minute ventilation similarly to sea level but both achieved higher values at peak exercise. In conclusion, airway responsiveness to methacholine at high altitude is well preserved despite the occurrence of interstitial pulmonary edema. We suggest that this may be the result of the increase in resting minute ventilation opposing the effects and/or the development of airway smooth muscle force, reduced gas density, and well preserved airway-to-parenchyma interdependence.

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    The most remote regions of globe represent some of the least disturbed ecosystems, yet they are threatened by air pollution and by climatic change. The Himalaya is one of the most isolated regions in the world and least explored wildernesses outside the Polar Regions; and it is for this reason that the Tibetan Plateau is often referred to as the ‘Third Pole’. Limnological survey (including chemistry, biology and sediment core studies) of lakes located between ca. 4500 and 5500 m a.s.l. has been performed from 1992 in the Kumbhu Valley, Nepal. Lake water chemical surveys reveal a constant increase of the ionic content of the lake water probably related to glacier retreat. Modern phytoplankton data compared with previous data point to an increasing trend in lake productivity. Zooplankton, benthos and thechamoebians provide useful biogeographical information. Paleolimnological reconstructions show the potential use of these sites in providing proxy data of past climatic changes in high altitude regions. Data collected of persistent organic pollutants show that the studied sites receive input related to long-range transport pollution. The aims and rationale for the future development of the Ev-K2-CNR Limnological Information System is discussed.

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    A Cimel sunphotometer operating in the framework of the AERONET project has been installed at the Himalayan Ev-K2-CNR Pyramid (5079 m a.s.l.) in the year 2006, as site Ev-K2-CNR. The observational activity will provide a characterization of the optical and microphysical properties of atmospheric aerosols, in particular of the atmospheric brown cloud (ABC) in the Himalayan region. This paper will describe the Cimel sunphotometer measurement technique, will introduce to the AERONET programme and will evaluate the contribution of the proposed Ev-K2-CNR AERONET site to the study of the ABC.

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    This work describes the preliminary results of a study aimed at: (1) assessing the ability of a general circulation model routinely run at the Epson Meteo Centre (CEM) in predicting daily rainfall; (2) evaluating the performance of satellite-derived precipitation estimates (namely, NOAA CPC CMORPH) over the same domain and during the same period. The CPC daily rain gauge analysis is used as reference for validation. The study focused on the Indian Monsoon during summer 2004, and comparison with a similar analysis at the mid-latitudes is also shown.

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    The Himalayan–Karakoram range is located in one of the most densely populated and very rapidly developing world areas. Monitoring of atmospheric composition in this area can play a relevant role in evaluating the background conditions of the free troposphere and quantifying the pollution present at high altitudes, as well as in studying regional and long-range transport phenomena. Due to technical and logistic difficulties in carrying out measurements at high altitude in the Himalaya, no systematic observations of atmospheric constituents are available for this area. Thus, a new measurement station in such a region represents a unique source of data, able to make up for the prior lack of this information. For these reasons, in the framework of the SHARE-Asia and ABC projects, a remote monitoring station, the ABC-Pyramid Laboratory, will be installed in the Khumbu valley near Mt. Everst at 5079 m a.s.l. Continuous in situ measurements of chemical, physical and optical properties of aerosol, surface ozone concentration, as well as non-continuous measurements of halocarbons and other greenhouse-gas concentrations will be carried out. This monitoring station was projected, realised and tested in Bologna at CNR-ISAC Institute during autumn 2005. It was designed to be controlled by remote login and to operate for the long-term in extremely adverse weather conditions. This station represents an ideal place for studying regional and long-range air mass transport, due to natural and human processes. Precious 5-day forecast information about air-masses circulation at the ABC-Pyramid site will be supplied daily by Lagrangian backward trajectories, including suitable forecasts of stratosphere-troposphere exchange phenomena.

  • The Ev-K2-CNR Project has been promoting and developing research at high altitude (>2,500 m a.sl.) in the Himalaya and Karakoram since 1987. Recently, activities have been focused on development of a monitoring network (stations at High Altitude for Research on the Environment in Asia: SHARE-Asia) to increase the environmental and geophysical scientific knowledge in these mountain regions. Research and monitoring activity at high altitude require a particular experience and a well-organized network. Ev-K2-CNR has accumulated a significant experience in managing a high altitude network of automatic weather stations along the Khumbu Valley (Nepal) and in northern Pakistan (Baltistan region) in the framework of the Coordinated Enhanced Observing Period Project. With the installation of an Atmospheric Brown Clouds Project (ABC) monitoring station near the Pyramid Laboratory-Observatory in 2006, near the base of Mount Everest, SHARE-Asia can also contribute to the study of atmospheric circulation of pollutants. The “ABC-Pyramid” is the first of a network of stations that are planned to be installed at altitudes between 2,500 and 5,000 m a.s.l. along the Himalayan–Karakoram chain. These stations will be operated under active cooperation with the local scientific community, creating ample cooperation between western countries and developing countries in the region.