A growing human footprint in the highlands

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Water Contamination ◽  
Land Use Changes ◽  
Ultraviolet B ◽  
Aquatic Biota ◽  
Low Oxygen ◽  
Aquatic Life ◽  
Aquatic Fauna ◽  
Human Footprint ◽  
The Face

Chapter 9 reviews the threats imposed by human activities to aquatic life at high altitude. High altitude regions of the inter-tropical belt are generally much more densely populated than their temperate counterparts. Therefore, they are directly affected by a number of human-related disturbances such as land use changes, water contamination, use and diversion, and the introduction of invasive species. The chapter details several unique environmental conditions of high altitude environments that make their aquatic biota particularly at risk in the face of anthropogenic disturbances. Among others, glaciers concentrate pollutants, low oxygen concentrations affect the response of aquatic fauna to stress, ultraviolet B modifies the bioavailability of contaminants, high primary productivity of grasslands encourages cattle ranching and fuels fires over large scales, and isolated watersheds favour species extinction following biological invasions.

High altitude waters in the face of climate change

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
Climate Change ◽  
High Altitude ◽  
Aquatic Organisms ◽  
High Sensitivity ◽  
Ice Melting ◽  
Aquatic Life ◽  
Physical Chemical ◽  
Mountain Climate ◽  
The Face ◽  
Ecosystem Level

Chapter 8 focuses on the effects of warming and changes in precipitation patterns on aquatic life at high altitude. Located near the edge of their climatic limits, in regions where the rate of warming is generally amplified compared with lowlands, high altitude aquatic systems present a high sensitivity to climate change. Changes in mountain climate create a number of indirect effects on aquatic life through the control of hydrological systems and processes, particularly those associated with the cryosphere (e.g. permafrost and ice melting) and the soil–vegetation interface (e.g. treeline expansion). The chapter then presents the three basic options faced by all aquatic organisms as their environmental conditions alter as a result of climate change: adapt, migrate, or perish. At an ecosystem level, small changes in physical, chemical, or biological characteristics can be amplified into major shifts in limnological properties.

Strategies and adaptations to aquatic life at high altitude

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Low Temperatures ◽  
Cold Adaptation ◽  
Inorganic Carbon ◽  
Direct Result ◽  
Aquatic Life ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Regulatory Capacity

Chapter 5 is focused on how organisms cope with the environmental conditions that are a direct result of high altitude. Organisms reveal a number of fascinating ways of dealing with a life at high altitude; for example, avoidance and pigmentation as protection against damaging high levels of ultraviolet radiation, accumulation of antifreeze proteins, and metabolic cold adaptation among species encountering low temperatures with the risk of freezing, oxy-regulatory capacity in animals due to low availability of oxygen, and root uptake from the sediment of inorganic carbon by plants living in waters poor in dissolved carbon dioxide. These and more adaptations are carefully described through a number of examples from famous flagship species in addition to the less well-known ones. Harsh environmental conditions work as an environmental filter that only allows the well-adapted species to slip through to colonize high altitude waters.

scholarly journals Oxygen regulation of macrophage migration inhibitory factor in human placenta

2007 ◽  
Vol 292 (1) ◽  
pp. E272-E280 ◽  
Author(s):  
Francesca Ietta ◽  
Yuanhong Wu ◽  
Roberta Romagnoli ◽  
Nima Soleymanlou ◽  
Barbara Orsini ◽  
...  
Keyword(s):  
High Altitude ◽  
Migration Inhibitory Factor ◽  
Macrophage Migration Inhibitory Factor ◽  
Inhibitory Factor ◽  
Extravillous Trophoblast ◽  
Macrophage Migration ◽  
Low Oxygen ◽  
Placental Development

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7–10 wk and lower levels at 11–12 wk until term. Exposure of villous explants to 3% O2 resulted in increased MIF expression and secretion relative to standard conditions (20% O2). DMOG treatment under 20% O2 increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.

Minimal Dissolved Oxygen Requirements of Aquatic Life with Emphasis on Canadian Species: a Review

1975 ◽  
Vol 32 (12) ◽  
pp. 2295-2332 ◽  
Author(s):  
John C. Davis
Keyword(s):  
Dissolved Oxygen ◽  
Water Body ◽  
Physical Factors ◽  
Seasonal Temperature ◽  
Low Oxygen ◽  
Aquatic Life ◽  
Invertebrate Species ◽  
Oxygen Regime ◽  
Response Thresholds ◽  
Oxygen Requirements

This article reviews the sensitivity, responses, response thresholds, and minimum oxygen requirements of marine and freshwater organisms with strong emphasis on Canadian species. The analysis attempts to define low dissolved oxygen thresholds which produce some physiological, behavioral, or other response in different species.Oxygen availability is discussed with reference to seasonal, geographical, or spatial variation in dissolved oxygen. Factors affecting availability of dissolved oxygen include atmospheric exchange, mixing of water masses, upwelling, respiration, photosynthesis, ice cover, and physical factors such as temperature and salinity. Dissolved oxygen terminology is summarized and tables are included for both fresh and saltwater O2 solubility at different temperatures.Incipient O2 response thresholds are used in a statistical analysis to develop oxygen criteria for safeguarding various groups of freshwater and marine fish. These include mixed freshwater fish populations including or excluding salmonids, freshwater salmonid populations, salmonid larvae or mature salmonid eggs, marine anadromous and nonanadromous species. Criteria are based on threshold oxygen levels which influence fish behavior, blood O2 saturation, metabolic rate, swimming ability, viability and normal development of eggs and larvae, growth, circulatory dynamics, ventilation, gaseous exchange, and sensitivity to toxic stresses. The criteria provide three levels of protection for each fish group and are expressed as percentage oxygen saturation for a range of seasonal temperature maxima.Oxygen tolerances and responses of aquatic invertebrates to low oxygen are reviewed for freshwater and marine species according to habitat. No invertebrate criteria are proposed owing to the capacity for many invertebrate species to adopt anaerobic metabolism during low O2 stress. It is suggested that the criteria proposed for fish species will provide a reasonable safeguard to most invertebrate species. It appears likely, however, that a change in oxygen regime to one of increased O2 scarcity will probably influence invertebrate community structure.It is suggested that criteria for protection of aquatic life be implemented by groups of experienced individuals. The group should consider the natural oxygen regime for a specific water body and its natural variability, the aquatic life therein and its value, importance, relative O2 sensitivity, and the possibility of interactions with toxicants and other factors that may compound the stress produced by low O2 on aquatic life. Each water body and its aquatic life should be considered as a unique situation and criteria application should not encompass diverse areas, habitats, or biological associations as if they were identical.

scholarly journals The Expression Regulatory Network in the Lung Tissue of Tibetan Pigs Provides Insight Into Hypoxia-Sensitive Pathways in High-Altitude Hypoxia

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanan Yang ◽  
Haonan Yuan ◽  
Tianliang Yang ◽  
Yongqing Li ◽  
Caixia Gao ◽  
...  
Keyword(s):  
High Altitude ◽  
Regulatory Networks ◽  
Alveolar Wall ◽  
Potential Candidate ◽  
Low Oxygen ◽  
Structure Damage ◽  
High Altitude Adaptation ◽  
Tibetan Pigs ◽  
Altitude Adaptation ◽  
Insight Into

To adapt to a low-oxygen environment, Tibetan pigs have developed a series of unique characteristics and can transport oxygen more effectively; however, the regulation of the associated processes in high-altitude animals remains elusive. We performed mRNA-seq and miRNA-seq, and we constructed coexpression regulatory networks of the lung tissues of Tibetan and Landrace pigs. HBB, AGT, COL1A2, and EPHX1 were identified as major regulators of hypoxia-induced genes that regulate blood pressure and circulation, and they were enriched in pathways related to signal transduction and angiogenesis, such as HIF-1, PI3K-Akt, mTOR, and AMPK. HBB may promote the combination of hemoglobin and oxygen as well as angiogenesis for high-altitude adaptation in Tibetan pigs. The expression of MMP2 showed a similar tendency of alveolar septum thickness among the four groups. These results indicated that MMP2 activity may lead to widening of the alveolar wall and septum, alveolar structure damage, and collapse of alveolar space with remarkable fibrosis. These findings provide a perspective on hypoxia-adaptive genes in the lungs in addition to insights into potential candidate genes in Tibetan pigs for further research in the field of high-altitude adaptation.

scholarly journals High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

2016 ◽  
Vol 10 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Aibek E. Mirrakhimov ◽  
Kingman P. Strohl
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Indoor Air Pollution ◽  
Screening Tools ◽  
Heart Catheterization ◽  
Low Oxygen ◽  
Lower Altitude ◽  
Individualized Approach ◽  
Chest X Ray ◽  
Low Oxygen Concentration

High-altitude pulmonary hypertension (HAPH) affects individuals residing at altitudes of 2,500 meters and higher. Numerous pathogenic variables play a role in disease inception and progression and include low oxygen concentration in inspired air, vasculopathy, and metabolic abnormalities. Since HAPH affects only some people living at high altitude genetic factors play a significant role in its pathogenesis. The clinical presentation of HAPH is nonspecific and includes fatigue, shortness of breath, cognitive deficits, cough, and in advanced cases hepatosplenomegaly and overt right-sided heart failure. A thorough history is important and should include a search for additional risk factors for lung disease and pulmonary hypertension (PH) such as smoking, indoor air pollution, left-sided cardiac disease and sleep disordered breathing. Twelve-lead electrocardiogram, chest X-ray and echocardiography can be used as screening tools. A definitive diagnosis should be made with right-sided heart catheterization using a modified mean pulmonary artery pressure of at least 30 mm Hg, differing from the 25 mm Hg used for other types of PH. Treatment of HAPH includes descent to a lower altitude whenever possible, oxygen therapy and the use of medications such as endothelin receptor antagonists, phosphodiesterase 5 blockers, fasudil and acetazolamide. Some recent evidence suggests that iron supplementation may also be beneficial. However, it is important to note that the scientific literature lacks long-term randomized controlled data on the pharmacologic treatment of HAPH. Thus, an individualized approach to treatment and informing the patients regarding the benefits and risks of the selected treatment regimen are essential.

Modeling on n-Heptane Pool Fire Behavior in an Altitude Chamber

2013 ◽  
Author(s):  
Quanyi Liu ◽  
Wei Yao ◽  
Jiusheng Yin ◽  
Rui Yang ◽  
Hui Zhang
Keyword(s):  
High Altitude ◽  
Burning Rate ◽  
Pressure Effect ◽  
Fire Behavior ◽  
Low Pressure ◽  
Pool Fire ◽  
Low Oxygen ◽  
Fire Plume ◽  
Plume Temperature ◽  
Modeling Data

Airplane as one of the important transport vehicles in our life, its safety problem related to in-flight fire has attracted a wide-spread attention. The combustion behavior of the cabin fire in flight shows some special characteristics because of the high-altitude environment with low-pressure and low oxygen concentration. A low-pressure chamber of size 2 m×3 m×2 m has been built to simulate high-altitude environments, where multiple static pressures for pool fire tests can be configured in the range between standard atmospheric pressure 101.3KPa and 30KPa. Two different sizes of pool fires were tested. Then corresponding modeling were conducted by a LES code FDS V5.5 to examine the mechanism of pressure effect on the n-Heptane pool fire behavior. The burning of liquid fuel was modeled by a Clausius-Clapeyron relation based liquid pyrolysis model. The modeling data was validated against the experimental measurements. The mass burning rate of free-burning pool fire decreases with the decreasing of pressure, which was observed from the modeling to be due to the reduction of flame heat feedback to the fuel surface. Under low pressure, the fire plume temperature increases for the same burning rate. The mechanism of pressure effect on fire behavior was analyzed based on the modeling data.

Physiology in Medicine: A physiologic approach to prevention and treatment of acute high-altitude illnesses

2015 ◽  
Vol 118 (5) ◽  
pp. 509-519 ◽  
Author(s):  
Andrew M. Luks
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Acute Mountain Sickness ◽  
Travel Medicine ◽  
Barometric Pressure ◽  
Time Frame ◽  
Low Oxygen ◽  
Organ Systems ◽  
Prevention And Treatment ◽  
Physiologic Responses

With the growing interest in adventure travel and the increasing ease and affordability of air, rail, and road-based transportation, increasing numbers of individuals are traveling to high altitude. The decline in barometric pressure and ambient oxygen tensions in this environment trigger a series of physiologic responses across organ systems and over a varying time frame that help the individual acclimatize to the low oxygen conditions but occasionally lead to maladaptive responses and one or several forms of acute altitude illness. The goal of this Physiology in Medicine article is to provide information that providers can use when counseling patients who present to primary care or travel medicine clinics seeking advice about how to prevent these problems. After discussing the primary physiologic responses to acute hypoxia from the organ to the molecular level in normal individuals, the review describes the main forms of acute altitude illness—acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema—and the basic approaches to their prevention and treatment of these problems, with an emphasis throughout on the physiologic basis for the development of these illnesses and their management.

Characterisation of Spiti Horses of India

2004 ◽  
Vol 34 ◽  
pp. 75-81 ◽  
Author(s):  
R.K. Pundir
Keyword(s):  
High Altitude ◽  
Breeding Season ◽  
Body Length ◽  
Himachal Pradesh ◽  
The Body ◽  
Intensive Management ◽  
Alpine Pasture ◽  
Service Period ◽  
Face Length ◽  
The Face

SummaryThe breeding tract of Spiti horses is located in the Kaja subdivision of the Lahul and Spiti district and the Yanthang area of the Kinnaur district of Himachal Pradesh in India. The horses in this area are smaller in height and called Spiti ponies. They are reared as pack animals at high altitude. Their body is well developed with fairly strong bones. The mane is long and has hairs of 25 to 40 cm in length. The body is solid, displaying and alert attitude, the face is convex, the ears are erect and the eyes are black. The tail is medium in length and straight. The horses are docile in temperament. The body colours are grey, brown, black and piebald. On an average, these horses stand 129 cm height, have a body length of 100 cm, a heart girth of 148 cm, an ear length of 15 cm and a face length of 50 cm. Animals are reared on grazing (alpine pasture) from May to November and stall fed from December to April. The breeding season is from February to July. The average age at first fertile service, age at first foaling, gestation period, service period and foaling interval were estimated as 1 054, 1 297, 333, 63 and 516 days, respectively under intensive management at Kamand farm. It has also been ascertained from various sources that their number is declining rapidly, however breed population statistics are not available. There is, therefore, an urgent need to conserve this breed.

Teaching the physiology of adaptation to hypoxic stress with the aid of a classic paper on high altitude by Houston and Riley

2008 ◽  
Vol 32 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Etain A. Tansey
Keyword(s):  
High Altitude ◽  
United States Navy ◽  
The United States ◽  
The Body ◽  
Adaptive Responses ◽  
Low Oxygen ◽  
American Physiological Society ◽  
Subsequent Publication ◽  
Oxygen Transport System ◽  
Classic Paper

Many pathological conditions exist where tissues exhibit hypoxia or low oxygen tension. Hypoxic hypoxia arises when there is a reduction in the amount of oxygen entering the blood and occurs in healthy people at high altitude. In 1946, research sponsored by the United States Navy led to the collection and subsequent publication of masses of data demonstrating the physiological consequences and adaptations of ascent to high altitude. This article describes how a figure from a 1947 paper from the American Physiological Society Legacy collection (Houston CS, Riley RL. Respiratory and circulatory changes during acclimatization to high altitude. Am J Physiol 149: 565–588) may be used to allow students to review their understanding of some of the generalized effects of hypoxia on the body. In particular, this figure summarizes some of the adaptive responses that take place in the oxygen transport system as a consequence of prolonged hypoxia.

Sign in / Sign up

Export Citation Format

Share Document