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Results 301 - 350 of 811
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van Dijk Pim - - 2003
The physiological vulnerability of distortion product otoacoustic emissions (DPOAEs) was investigated in the leopard frog, Rana pipiens pipiens. For each frog, DPOAEs were recorded from the amphibian and the basilar papillae. Measurements were taken before and after either the arrest of oxygen supply due to cardioectomy, or the destruction of ...
Pilmanis Andrew A - - 2003
INTRODUCTION: Loss of aircraft cabin pressurization can result in very rapid decompression rates. The literature contains reports of increased or unchanged levels of altitude decompression sickness (DCS) resulting from increasing the rate of decompression. We conducted two prospective exposure profiles to quantify the DCS risk at 12,192 m (40,000 ft), ...
Ashenden Michael J - - 2003
BACKGROUND AND OBJECTIVES: ON- and OFF-model scores derived from blood parameters sensitive to erythropoiesis have been shown to be a useful tool to identify athletes who are currently injecting erythropoietin to enhance performance or those who have recently stopped doing so. We investigated changes in blood parameters and model scores ...
Zhong-Yuan Shi - - 2003
The simulated dive experiments were conducted at the high altitude of 4500 meters and 5000 meters, for the requirement of diving operation in the lakes at the altitude of 4442 meters for the construction of large-scale hydroelectric power station. The high & low pressure chamber-complex was used, and 15 professional ...
Dilharreguy Bixente - - 2003
Experimental and modeling studies were used to estimate the effect of different sampling rates (repetition times, TR) and different sampling positions on the estimates of the temporal properties of the hemodynamic response function (HRF) derived from fMRI studies. Data were acquired at a TR of 250 ms and then subjected ...
Russell Michael F - - 2003
An analytical method for determining the quality and hence the chemical variety status of tea tree transplants is described. The key to the procedure was found to be the leaf age of the test material. Investigation at very early development stages was seen to give misleading results due to the ...
Beidleman Beth A - - 2003
Chronic altitude residence improves muscular performance at altitude, but the effect of intermittent altitude exposures (IAE) on muscular performance at altitude has not been defined. The purpose of this study was to determine the effects of 3 wk of IAE, in combination with rest and cycle training, on muscular performance ...
West John B - - 2003
George Ingle Finch (1888-1970) was the first person to prove the great value of supplementary oxygen for climbing at extreme altitudes. He did this during the 1922 Everest expedition when he and his companion, Geoffrey Bruce, reached an altitude of 8,320 m, higher than any human had climbed before. Finch ...
Arz Helge W - - 2003
Paleosalinity and terrigenous sediment input changes reconstructed on two sediment cores from the northernmost Red Sea were used to infer hydrological changes at the southern margin of the Mediterranean climate zone during the Holocene. Between approximately 9.25 and 7.25 thousand years ago, about 3 per thousand reduced surface water salinities ...
Urban L - - 2003
Variations in leaf nitrogen concentration per unit mass (Nm) and per unit area (Na), mass-to-area ratio (Ma), total nonstructural carbohydrates (Ta), and photosynthetic capacity (maximum carboxylation rate, electron transport capacity, rate of phosphate release in triose phosphate utilization and dark respiration rate) were studied within the digitized crowns of two ...
Nardini Andrea - - 2003
The impact of leaf vein blockage on leaf hydraulic conductance (K(L)), gas exchange (g(L)) and water potential (Psi(L)) was studied in Prunus laurocerasus L., a broad-leaved evergreen. For this purpose, leaves were measured for the three variables above, either with an intact leaf blade (controls) or with the midrib cut ...
Niess Andreas Michael - - 2003
PURPOSE: The purpose of the present field study was to explore whether extensive interval training (IT) performed with a similar behavior of blood lactate (LA) at an altitude of 1800 m (ALT) and near sea level (SL) goes along with a comparable hormonal, metabolic, and acute phase response in highly ...
Mairbäurl Heimo - - 2003
Hypoxia inhibits activity and expression of ion transport proteins of cultured lung alveolar epithelial cells. Here we tested, whether in vivo hypoxia at high altitude (4,559 m) also inhibits lung ion transport. Transepithelial nasal potentials (NP) were determined as a surrogate measure of lung ion transport activity before and during ...
Pronk Marieke - - 2003
The arterial blood lactate [La] response to exercise increases in acute hypoxia, but returns to near the normoxic (sea level, SL) response after 2 to 5 weeks of altitude acclimatization. Recently, it has been suggested that this gradual return to the SL response in [La], known as the lactate paradox ...
Loeppky Jack A - - 2003
A few studies have reported increased body temperature (T(o)) associated with acute mountain sickness (AMS), but these usually include exercise, varying environmental conditions over days, and pulmonary edema. We wished to determine whether T(o) would increase with AMS during early exposure to simulated altitude at rest. Ninety-four exposures of 51 ...
West John B - - 2003
The Swiss expedition to Everest (altitude 8,848 m) in the spring of 1952 very nearly attained the summit with two of the climbers reaching 8,595 m. This would have been the first ascent of Everest. One main reason for failure was the inadequate oxygen equipment which was modified from sets ...
Bhaumik G - - 2003
Human work performances decreases at high altitude (HA). This decrement does not appear to be similar for every individual, may be due to variety of factors like elevation, mode of induction, work intensity, physical condition and specificity of the subjects. The purpose of the study was to evaluate the effects ...
Fréchou C - - 2003
In recent years, particular attention was paid to the long-lived radionuclides discharged with authorized low-level radioactive liquid and gaseous effluents by the nuclear spent fuel reprocessing plants of La Hague and Sellafield. The knowledge of (129)I (half-life=15.7 x 10(6) a) distribution in the environment is required to assess the radiological ...
Kobayashi Makio - - 2002
The purpose of this study was to investigate the effect on the vibratory characteristics of a cast hollow obturator prosthesis retainer when varying its bulb height. Bulb parts with high (H), middle (M), and low (L) lateral walls were prepared. A Vibration Generator was used to excite the three obturators, ...
Webb James T - - 2002
INTRODUCTION: Since strenuous exercise for 10 min during preoxygenation was shown to provide better protection from decompression sickness (DCS) incidence than resting preoxygenation, a logical question was: would a longer period of strenuous exercise improve protection even further? HYPOTHESIS: Increased strenuous exercise duration during preoxygenation increases DCS protection. METHODS: There ...
Ma Jian Feng - - 2002
Rice (Oryza sativa) accumulates silicon (Si) in the tops to levels up to 10.0% of shoot dry weight, but the mechanism responsible for high Si uptake by rice roots is not understood. We isolated a rice mutant (GR1) that is defective in active Si uptake by screening M(2) seeds (64,000) ...
Calbet J A L - - 2002
The principal aim of this investigation was to determine the influence of blood haemoglobin concentration ([Hb]) on maximal exercise capacity and maximal O(2) consumption (V(O(2),max)) in healthy subjects acclimatised to high altitude. Secondarily, we examined the effects of [Hb] on the regulation of cardiac output (CO), blood pressure and muscular ...
Léon-Velarde Fabiola - - 2003
Peripheral chemoreflex function was studied in high-altitude (HA) natives at HA, in patients with chronic mountain sickness (CMS) at HA, and in sea-level (SL) natives at SL. Results were as follows. 1) Acute ventilatory responses to hypoxia (AHVR) in the HA and CMS groups were approximately one-third of those of ...
Askew E W - - 2002
A significant portion of the world's geography lies above 10,000 feet elevation, an arbitrary designation that separates moderate and high altitude. Although the number of indigenous people living at these elevations is relatively small, many people travel to high altitude for work or recreation, exposing themselves to chronic or intermittent ...
Haske Terry L - - 2002
INTRODUCTION: Current Air Force Instructions (AFIs) allow flight of unrestricted duration in unpressurized aircraft up to 25,000 ft. Supplemental oxygen is required to prevent hypoxia, but decompression sickness (DCS) is not adequately considered in current oxygen use guidelines. Recent information from the Air Force Research Laboratory (AFRL) DCS database, combined ...
Dehnert C - - 2002
The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - ...
Greene H M - - 2002
Altitude evokes physiological adjustments that include not only respiratory and cardiovascular properties, but also metabolic function, renal and endocrine responses. The purpose of the present study was designed to expand our understanding of the physiological process involved with acclimatisation to high altitude in equids. The study examined temporal effects on ...
Crum Nancy - - 2002
An outbreak of coccidioidomycosis among 22 Navy SEALs occurred during training exercises in Coalinga, California. Ten (45%) of the 22 men had serologic evidence of acute coccidioidomycosis, the highest attack rate ever reported for a military unit. All case patients were symptomatic, and 50% had abnormal chest radiographs. There were ...
Cymerman Allen - - 2002
BACKGROUND: An objective method that accurately quantifies the severity of Acute Mountain Sickness (AMS) symptoms is needed to enable more reliable evaluation of altitude acclimatization and testing of potentially beneficial interventions. HYPOTHESIS: Changes in human articulation, as quantified by timed variations in acoustic waveforms of specific spoken words (voice onset ...
Rietjens G J W M - - 2002
The purpose of this study was to monitor general and individual changes in hematological variables during long-term endurance training, detraining and altitude training in elite Olympic distance triathletes. Over a period of three years, a total of 102 blood samples were collected in eleven (7-male and 4 female) elite Olympic ...
Balldin Ulf I - - 2002
BACKGROUND: A discrepancy exists between the incidence of ground-based decompression sickness (DCS) during simulated extravehicular activity (EVA) at hypobaric space suit pressure (20-40%) and crewmember reports during actual EVA (zero reports). This could be due to the effect of gravity during ground-based DCS studies. HYPOTHESIS: At EVA suit pressures of ...
Christensen C C - - 2002
Several publications have reported effects of hypobaric conditions in patients with chronic obstructive pulmonary disease. To the current authors' knowledge, similar studies concerning patients with restrictive lung disease have not been published. The effect of simulated air travel in a hypobaric chamber on arterial blood gases, blood pressure, and cardiac ...
Bult Johannes H F - - 2002
Food aromas generally are complex mixtures of volatiles. In the present study, we investigated the joint effects of hexyl acetate, trans-2-hexenal and 1-hexanol on the multi-attribute perception of an apple aroma. The first two substances were identified earlier as positive contributors to the apple aroma (high character impact), whereas the ...
Tannheimer M - - 2002
Thirteen healthy European mountaineers (11 male, 2 female) participated in the 62-day German-Pakistani Research Expedition to Broad Peak (8047 m) in the Karakorum, Pakistan. During ascent, base camp stay and approach to the summit, oxygen saturation was measured by pulse oximetry at rest, during exercise and during sleep; in addition, ...
Gerasimov Madina R - - 2002
With the goal of investigating the pharmacokinetics of the abused solvent, toluene we have adapted the rapid coupling of methyl iodide with tributylphenylstannane mediated by palladium(0) complex to the synthesis of no-carrier-added [11C]toluene starting with 11CH(3)I. Two methods for purification and formulation of the tracer were developed. The first one ...
Bogaard Harm J - - 2002
After acclimatization to high altitude, maximal exercise cardiac output (QT) is reduced. Possible contributing factors include 1) blood volume depletion, 2) increased blood viscosity, 3) myocardial hypoxia, 4) altered autonomic nervous system (ANS) function affecting maximal heart rate (HR), and 5) reduced flow demand from reduced muscle work capability. We ...
Hochachka P W - - 2002
For many years, physiologists have puzzled over the observation that, during maximum aerobic exercise, high-altitude natives generate lower-than-expected amounts of lactate; the higher the altitude, the lower the postexercise blood lactate peak. This paradoxical situation may be caused mainly by upregulated metabolic control contributions from cell ATP demand and ATP ...
Feriche Fernández-Castanys B - - 2002
The effect of sodium citrate intake on anaerobic performance in normoxia and acute hypoxia was tested in 17 healthy male subjects. The subjects underwent a high-intensity exercise protocol in conditions of normoxia (N) and at 2320 m above the sea level (H). Each condition was combined with the intake of ...
Schena F - - 2002
BACKGROUND: The aim of this study was to evaluate the effects of training at altitude on plasma nitrite/nitrate and erythropoietin levels since previously it has been reported an interaction of the NO/cGMP system in erythropoietin production. METHODS: Nine physically trained cross-country male skiers, usually living at 800-1200 m altitude, underwent ...
Kao Wei-Fong - - 2002
BACKGROUND: Although there are more than 200 peaks higher than 3000 m in the Taiwan Alps, no data on the incidence of acute mountain sickness (AMS) are available. This study investigated the incidence of AMS in Jade Mountain climbers. METHODS: The study was performed at the entrance of Jade Mountain, ...
Arsac Laurent M - - 2002
The present study was designed to investigate the role of reduced air density on the energetics of 100 m running at altitude. A mathematical supply-demand model was used where supply had two components, aerobic and anaerobic and demand had three components: the cost of overcoming non-aerodynamic forces (C(na)), the cost ...
Bernez Ivan - - 2002
Macrophytes were studied downstream of the Rophémel hydroelectric dam on the River Rance (Côtes d'Armor Department, western France) to assess the effects of hydroelectric functioning on river macrophyte communities. We studied ten representative sections of the hydro-peaking channel on five occasions in 1995 and 1996, on a 15-km stretch of ...
Nordahl SteinHelgeGlad - - 2002
BACKGROUND: Earlier studies have shown that acute hypoxia at simulated altitudes up to 18,000 ft affects postural control. The main objective of this study was to investigate whether this is caused by hypoxia or by other effects of reduced barometric pressure. Doppler monitoring was included to rule out venous gas ...
Beidleman Beth A - - 2002
PURPOSE: The purpose of this study was to determine whether substrate oxidation during submaximal exercise in women is affected by an acute exposure to 4300-m altitude and menstrual cycle phase. METHODS: Eight female lowlanders (mean +/- SD; 33 +/- 3 yr, 58 +/- 6 kg, 163 +/- 8 cm) completed ...
Zhuang Jianguo - - 2002
Tibetans are known as one of the largest and oldest high-altitude natives in the world and are among the best high-altitude-adapted ethnic groups. They exhibit greater vagal tone and less sympathetic stimulation than acclimatized lowlanders at high altitudes. Whether young native Tibetans who had spent long-term residence (more than 3 ...
Diesel Donald A - - 2002
BACKGROUND: Decompression to simulated altitude causes super-saturation of nitrogen desolved in body tissues and can result in venous gas emboli (VGE), which are usually "cleared" in the lung. Large intravenous boli of air administered to animals increase pulmonary artery pressure (PAP), and may induce cross-over of gas to the left ...
Axelsson Jóhann - - 2002
The prevalence of winter SAD was measured in two groups of a(lult Manitobans of wholly Icelandic (lescent, 210 resident in Winnipeg (50 degrees N) and 252 resident in the nearby Interlake district (50.5 degrees N), using the Seasonal Pattern Assessment Questionnaire (SPAQ). These groups live practically at the same latitude ...
Thomas D N - - 2002
The pack ice of Earth's polar oceans appears to be frozen white desert, devoid of life. However, beneath the snow lies a unique habitat for a group of bacteria and microscopic plants and animals that are encased in an ice matrix at low temperatures and light levels, with the only ...
Brutsaert Tom D - - 2002
At sea level normally menstruating women show increased ventilation (VE) and hemodynamic changes due to increased progesterone (P) and estrogen (E2) levels during the mid-luteal (L) compared to the mid-follicular (F) phase of the ovarian cycle. Such changes may affect maximal exercise performance. This repeated-measures, randomized study, conducted at 3600 ...
Lederman Susan J - - 2002
This study, which was conducted for the Bank of Canada, assessed the feasibility of presenting a raised texture feature together with a tactile denomination code on the next Canadian banknote series ($5, $10, $20, $50, and $100). Adding information accessible by hand would permit functionally blind individuals to independently denominate ...
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