high altitudes
Recently Published Documents


TOTAL DOCUMENTS

1256
(FIVE YEARS 158)

H-INDEX

50
(FIVE YEARS 5)

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 139
Author(s):  
Weixia Huang ◽  
Yunfang Zhong ◽  
Cuili Zhang ◽  
Mingxun Ren ◽  
Yanjun Du ◽  
...  

The southwestern mountains of Hainan Island are distributed in the southernmost tropical karst landscape of China, and the unique hydrological structure and frequent solifluction droughts lead to double water stress for local plants. Highly heterogeneous water environments affect the water–use characteristics of plants. Plants develop local adaptative mechanisms in response to changes in the external environment. In this paper, hydrogen–oxygen and carbon stable isotope technology, and physiological index measurements were applied to determine the leaf traits, water–use efficiency, and photosynthetic characteristics of Impatiens hainanensis leaves in dry and foggy seasons, hoping to expound the adaptation mechanism of I. hainanensis leaves to the water dynamics in dry and foggy seasons. In dry and foggy seasons (November 2018 to April 2019), the leaves of I. hainanensis at low and medium altitudes have the following combination of traits: larger leaf dry weights, leaf areas, and specific leaf areas; smaller leaf thicknesses and leaf dry matter contents; and higher chlorophyll contents. In comparison, the leaves of I. hainanensis at high altitudes have the following combination of traits: smaller leaf dry weights, leaf areas, and specific leaf areas; larger leaf thicknesses and leaf dry matter contents; and lower chlorophyll contents. The leaves of I. hainanensis can absorb fog water through their leaves. When the leaves are sprayed with distilled water, the water potential is low, the water potential value gradually increases, and the leaves have a higher rate of water absorption. The leaves of I. hainanensis at low and medium altitudes have the following water–use characteristics: high photosynthesis, high transpiration, and low water–use efficiency. At high altitudes, the Pn of I. hainanensis decreases by 8.43% relative to at low altitudes and by 7.84% relative to at middle altitudes; the Tr decreased by 4.21% relative to at low altitudes and by 3.38% relative to at middle altitude; the WUE increased by 16.61% relative to at low altitudes and increased by 40.79% relative to at middle altitudes. The leaves of I. hainanensis at high altitudes have the following water–use characteristics: low photosynthesis, low transpiration, and high water–use efficiency. I. hainanensis develop different physiological mechanisms of water adaptation by weighing the traits of the leaves and their use of light and water to obtain resources during dry and foggy seasons.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ivan Lopez ◽  
Reinaldo Aravena ◽  
Daniel Soza ◽  
Alicia Morales ◽  
Silvia Riquelme ◽  
...  

The Chilean workforce has over 200,000 people that are intermittently exposed to altitudes over 4,000 m. In 2012, the Ministry of Health provided a technical guide for high-altitude workers that included a series of actions to mitigate the effects of hypoxia. Previous studies have shown the positive effect of oxygen enrichment at high altitudes. The Atacama Large Millimeter/submillimeter Array (ALMA) radiotelescope operates at 5,050 m [Array Operations Site (AOS)] and is the only place in the world where pressure swing adsorption (PSA) and liquid oxygen technologies have been installed at a large scale. These technologies reduce the equivalent altitude by increasing oxygen availability. This study aims to perform a retrospective comparison between the use of both technologies during operation in ALMA at 5,050 m. In each condition, variables such as oxygen (O2), temperature, and humidity were continuously recorded in each AOS rooms, and cardiorespiratory variables were registered. In addition, we compared portable O2 by using continuous or demand flow during outdoor activities at very high altitudes. The outcomes showed no differences between production procedures (PSA or liquid oxygen) in regulating oxygen availability at AOS facilities. As a result, big-scale installations have difficulties reaching the appropriate O2 concentration due to leaks in high mobility areas. In addition, the PSA plant requires adequacy and maintenance to operate at a very high altitude. A continuous flow of 2–3 l/min of portable O2 is recommended at 5,050 m.


2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Luca Vecchioni ◽  
Marco Arculeo ◽  
Federico Marrone

Biological invasions are known to be among the most important threats to the long-term conservation of native biota, and their effects might be even more difficult to contrast when they are cryptic, i.e., when the non-native invaders cannot be easily recognised based on morphology, and can thus be confused with native taxa. Such cryptic invasions are known to widely occur in the cladoceran genus Daphnia O.F. Müller, 1785, so that the actual distribution and status of most species and lineages need to be checked with a genetic approach. In the frame of this work, we investigated if the Sicilian populations of D. (Daphnia) pulex Leydig, 1860 belonged to the allochthonous North American lineage, which is known to occur in several regions of the Palearctic and Afrotropical biogeographical regions, or rather to the autochthonous European lineage of the species. The molecular results obtained, based on a fragment of the mitochondrial gene encoding for NADH subunit dehydrogenase 5 (ND5), allowed us to rule out the allochthonous status of the species, confirming the presence of autochthonous relictual lineages of D. pulex in Sicily. The native status of these populations is in agreement with their local distribution, limited to natural and poorly-impacted water bodies mostly located in wooded areas at medium and high altitudes. The current local distribution of D. pulex in Sicily is possibly linked to the end of the last glacial maximum and the onset of warmer climatic conditions in the early Holocene, which led the species to take refuge in colder microthermal refugia located at high altitudes, determining their current relictual distribution. 


2021 ◽  
Author(s):  
Esteban Ortiz-Prado ◽  
Raul Fernandez-Naranjo ◽  
Jorge Eduardo Vásconez ◽  
Alexander Paolo Vallejo-Janeta ◽  
Ismar A Rivera-Olivero ◽  
...  

Abstract Background: SARS-CoV-2 has spread throughout the world, including areas located at high or very high altitudes. There is a debate about the role of high altitude hypoxia on viral transmission, incidence, and COVID-19 related mortality. This is the first comparison of SARS-CoV-2 viral load across elevations ranging from 0 to 4,300 m.Objective: To describe the SARS-CoV-2 viral load across samples coming from 62 cities located at low, moderate, high, and very high altitudes in Ecuador.Methodology: An observational analysis of viral loads among nasopharyngeal swap samples coming from a cohort of 4,929 patients with a RT-qPCR test positive for SARS-CoV-2.Results: The relationship between high and low altitude only considering our sample of 4,929 persons is equal in both cases and not significative (p-value 0.19). In the case of low altitude, adding the gender variable to the analysis, it was possible to find a significative difference between female and male gender (p-value 0.068). Considering initially gender and then altitude, it was possible to find a significative difference between high and low altitude for male gender (p-value 0.065). There is not enough evidence to state that viral load is affected directly by altitude range but adding a new variable as sex in the analysis shows that the presence of new variables influences the relationship of altitude range and viral load.Conclusions: There is no evidence that viral load differs at altitude level when we consider only one measure. Using as reference the variable gender is possible to note that at low altitude there is a difference between female and male gender. There is not difference between gender at high altitude level. In the case of considering gender as reference variable, it was possible to find that high and low altitude are different for male gender an equal for female gender. Viral load not only depends on altitude range; it also is affected by other variables like sex.


2021 ◽  
Author(s):  
Huaibin Wang ◽  
Zhiming Du ◽  
Tianwei Zhang ◽  
Qinzheng Wang ◽  
Yu Li ◽  
...  
Keyword(s):  

Osmia ◽  
2021 ◽  
Vol 9 ◽  
pp. 59-64
Author(s):  
Umer Bin Farook ◽  
Munazah Yaqoob ◽  
Mudasir Gani ◽  
Fons Verheyde

The presence of Xylocopa valga is reported for the first time from the high altitudes of Union Territory of Ladakh (more than 3,000 m above sea level), India. Several bees were observed in the area from May 2019 to September 2020, where it is considered to be a pest because of its aptness for making nests in residential and commercial buildings. The species has likely expanded its geographical area due to environmental changes. It is important to disseminate knowledge among Ladakh people about this bee to ensure the preservation of its populations.


Author(s):  
Diana Elizabeth Alcantara-Zapata ◽  
Aníbal J Llanos ◽  
Carolina Nazzal

Abstract Living at high altitudes and living with prostatic illness are two different conditions closely related to a hypoxic environment. People at high altitudes exposed to acute, chronic, or intermittent hypobaric hypoxia turn on several mechanisms at the system, cellular and molecular level to cope with oxygen atmosphere scarcity maintaining the oxygen homeostasis. This exposure affects the whole organism and function of many systems, such as cardiovascular, respiratory, and reproductive. On the other hand, malignant prostate is related to the scarcity of oxygen in the tissue microenvironment due to its low availability and high consumption due to the swift cell proliferation rates. Based on the literature, this similarity in the oxygen scarcity suggests that hypobaric hypoxia, and other common factors between these two conditions, could be involved in the aggravation of the pathological prostatic status. However, there is still a lack of evidence in the association of this disease in males at high altitudes. This review aims to examine the possible mechanisms that hypobaric hypoxia might negatively add to the pathological prostate function in males who live and work at high altitudes. More profound investigations of hypobaric hypoxia’s direct action on the prostate could help understand this exposure’s effect and prevent worse prostate illness impact in males at high altitudes.


2021 ◽  
Vol 2 (5) ◽  
pp. 6864-6881
Author(s):  
Anatoliy Bulychov

Since 1975 the Club of cavers based at Novosibirsk State University has performed an extra-ordinary method of caver training. Serious rock-climbing preparation and technical mountaineering with a background of intensive physical coaching have resulted in the discovery of large cave systems on the Altai and Sayan ranges. Overcoming high walls up inside the caves using free climbing and the use of aid techniques from alpinism was mandatory. Mountaineering skills allowed us to investigate plateaus on high altitudes on Zeravshanskiy (Mount Patroush) and Gissarskiy (Mount Hodja-Ahcha-Baroun) ranges, as well as pseudo karst in the vicinity of Khan-Tengri, Kilimanjaro, Aconcagua peaks, combined with geological surveying and prospecting. For all times the philosophical aspects of fair play in sports was an inherent part in our activity. The digital presentation of underground mapping and structures monitoring on surface made possible to discover a tectonic-geomorphologic speleogenesis of conglomerate caves of the Narva’s suite (Siberia, Manskiy trough). The most outstanding caves of the massif are Big Oreshnaya and Badjeiskaya, and unique as their length is about 50 km and 10 km respectively, while in general, there is no significant development of caves in such rocks in the world. Our geomorphologic observations show the presence of large linear faults, which played an obvious role in karstogenesis, and the presence of signs of near-surface cave levels, which have not been discovered yet.   Desde 1975, el Club de espeleólogos con sede en la Universidad Estatal de Novosibirsk ha llevado a cabo un método extraordinario de formación de espeleólogos. Una seria preparación de escalada en roca y montañismo técnico con un fondo de entrenamiento físico intensivo han dado como resultado el descubrimiento de grandes sistemas de cuevas en las cordilleras de Altai y Sayan. La superación de altas paredes en el interior de las cuevas mediante la escalada libre y el uso de técnicas de ayuda del alpinismo era obligatoria. Los conocimientos de alpinismo nos permitieron investigar las mesetas de gran altura en las cordilleras Zeravshanskiy (Monte Patroush) y Gissarskiy (Monte Hodja-Ahcha-Baroun), así como el pseudokarst en las cercanías de los picos Khan-Tengri, Kilimanjaro, Aconcagua, combinados con la topografía y la prospección geológica. En todo momento los aspectos filosóficos del juego limpio en el deporte fueron parte inherente a nuestra actividad. La presentación digital de la cartografía subterránea y el seguimiento de las estructuras en la superficie permitieron descubrir una espeleogénesis tectónica-geomorfológica de las cuevas de conglomerado del conjunto de Narva (Siberia, la depresión Manskiy). Las cuevas más destacadas del macizo son Big Oreshnaya y Badjeiskaya, y únicas ya que su longitud es de unos 50 km y 10 km respectivamente, mientras que, en general, no hay un desarrollo significativo de cuevas en tales rocas en el mundo. Nuestras observaciones geomorfológicas muestran la presencia de grandes fallas lineales, que desempeñaron un papel evidente en la karstogénesis, y la presencia de indicios de niveles de cuevas cercanos a la superficie, que aún no han sido descubiertos.


2021 ◽  
Vol 12 ◽  
Author(s):  
Pooja ◽  
Vandana Sharma ◽  
Ram Niwas Meena ◽  
Koushik Ray ◽  
Usha Panjwani ◽  
...  

Acute exposure to high altitude perturbs physiological parameters and induces an array of molecular changes in healthy lowlanders. However, activation of compensatory mechanisms and biological processes facilitates high altitude acclimatization. A large number of lowlanders stay at high altitude regions from weeks to months for work and professional commitments, and thus are vulnerable to altitude-associated disorders. Despite this, there is a scarcity of information for molecular changes associated with long-term stay at high altitudes. In the present study, we evaluated oxygen saturation (SpO2), heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) of lowlanders after short- (7 days, HA-D7) and long-term (3 months, HA-D150) stay at high altitudes, and used TMT-based proteomics studies to decipher plasma proteome alterations. We observed improvements in SpO2 levels after prolonged stay, while HR, SBP, and DBP remained elevated as compared with short-term stay. Plasma proteomics studies revealed higher levels of apolipoproteins APOB, APOCI, APOCIII, APOE, and APOL, and carbonic anhydrases (CA1 and CA2) during hypoxia exposure. Biological network analysis also identified profound alterations in lipoprotein-associated pathways like plasma lipoprotein assembly, VLDL clearance, chylomicron assembly, chylomicron remodeling, plasma lipoprotein clearance, and chylomicron clearance. In corroboration, lipid profiling revealed higher levels of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) for HA-D150 whereas high density lipoproteins (HDL) levels were lower as compared with HA-D7 and sea-level indicating dyslipidemia. We also observed higher levels of proinflammatory cytokines IL-6, TNFα, and CRP for HA-D150 along with oxidized LDL (oxLDL), suggesting vascular inflammation and proartherogenic propensity. These results demonstrate that long-term stay at high altitudes exacerbates dyslipidemia and associated disorders.


Sign in / Sign up

Export Citation Format

Share Document