Mountain Altitude Research Articles

MORBIDITY AND MORTALITY FROM CARDIOVASCULAR DISEASES ACCORDING TO THE SEA-LEVEL RELATED ALTITUDE OF A REGION

It is known that the common risk factors (RF) of cardiovascular diseases (CVD) do exist and do influence all people the same. Among them are arterial hypertension, smoking, total cholesterol, obesity etc. However there are specifics of RF realization connected to climatogeographic specifics, i.e. high mountain altitudes. The review is concerned on the influence of the high altitude influence on RF of CVD. Some papers show that in high altitudes inhabitants the RF of CVD were prognostically malevolent, but the level of total and coronary mortality was lower in mountain inhabitants that can be explained by more intensive physical exertion with the background moderate hypoxia. There is an opinion that lower mortality in higher altitudes can be explained as connected with physiological adaptation to altitude and/or specifics of the climate (i.e. with UV-rays exposure, those become more intensive by 10% every 300 m). Lipidogramm are supposedly linked to moderate hypoxia and lowering of temperature, also the diet specifics might influence. However there is no stabile relation of mortality and the parameters studied. So the results collected in different trials are still controversial. But if long-term living in higher altitudes, secondarily, by the activation of adaptation capacities of the body, diet specifics and physical exertion, leads to the decrease of morbidity and mortality from CVD, short-term visiting of the mountains might be harmful for some persons and this requires individualized approach to recommendations of prevention.

Use of CCD to Detect Terrestrial Cosmic Rays at Ground Level: Altitude vs. Underground Experiments, Modeling and Numerical Monte Carlo Simulation

In this work, we used a commercial charge-coupled device (CCD) camera to detect and monitor terrestrial cosmic rays at ground level. Multi-site characterization has been performed at sea level (Marseille), underground (Modane Underground Laboratory) and at mountain altitude (Aiguille du Midi–Chamonix Mont-Blanc at $+3,780~\hbox{m}$ of altitude) to separate the atmospheric and alpha particle emitter’s contributions in the CCD response. An additional experiment at avionics altitude during a long-haul flight has been also conducted. Experiment results demonstrate the importance of the alpha contamination in the CCD response at ground level and its sensitivity to charged particles. Experimental data as a function of CCD orientation also suggests an anisotropy of the particle flux for which the device is sensitive. A complete computational modeling of the CCD imager has been conducted, based on a simplified 3D CCD architecture deduced from a reverse engineering study using electron microscopy and physico-chemical analysis. Monte Carlo simulations evidence the major contribution of low energy (below a few MeV) protons and muons in the CCD response. Comparison between experiments and simulation shows a good agreement at ground level, fully validated at avionics altitudes with a much higher particle flux and a different particle cocktail composition.

Pathophysiological changes in mitochondria of mammalian exposed to hypoxia at high altitude

As human beings ascend to high altitude, a number of reactions may occur against hypoxic injuries. These hypoxic responses are related to intake, transportation and utility of the oxygen. As a crucial subcellular organelle of oxygen utility, mitochondrion is a central link of high altitude acclimatization, adaptation and mountain sicknesses. In this review, we discussed the recent advances in researches on hypoxic mitochondrial responses at high altitude.

Diversity of endophytic bacteria associated with nodules of two indigenous legumes at different altitudes of the Qilian Mountains in China

A total of 201 endophytic root nodule-associated bacteria collected from two legumes indigenous to different Qilian Mountain altitudes (Hexi Corridor) were characterized through 16S rDNA polymerase chain reaction (PCR)-restriction fragment length polymorphism, 16S rRNA gene sequence analysis, and enterobacterial repetitive intergenic consensus-PCR clustering. The isolates phylogenetically belonged to 35 species in the Phyllobacterium, Ensifer, Rhizobium, Microvirga, Sphingomonas, Paracoccus, Mycobacterium, Paenibacillus, Cohnella, Sporosarcina, Bacillus, Staphylococcus, Brevibacterium, Xenophilus, Erwinia, Leclercia, Acinetobacter, and Pseudomonas genera. Phylogenetic nodA sequence analysis showed higher similarity to Sinorhizobium meliloti with strains related to the Rhizobium, Sinorhizobium, and Acinetobacter genera. Sequence analysis of the nifH gene revealed that the strains belonging to Xenophilus, Acinetobacter, Phyllobacterium, and Rhizobium had genes similar to those of Mesorhizobium and Sinorhizobium. The results indicated that horizontal gene transfer could have occurred between rhizobia and non-rhizobial endophytes. Canonical correspondence analysis revealed that altitude and host plant species contributed more to the bacterial endosymbiont separation than other ecological factors. This study provided valuable information on the interactions between symbiotic bacteria, non-symbiotic bacteria and their habitats, and thus provided knowledge on their genetic diversity and ecology.

Observation of a rare cosmic ray event at mountain altitude

Existence of strangelets in cosmic rays has been predicted even at mountain altitudes ∼3–4km with extremely low abundance. We exposed an appropriate passive detector to cosmic rays at Darjeeling, India, at an atmospheric pressure of 765hPa, as a pilot study to determine its suitability for the detection of strangelets in a large area detector array through long-term exposure. During the analysis we found a highly unusual event consisting of a cluster of six identical nuclear tracks. We argue that even the most mundane explanation of this event requires unusual physics, the first possible observation of multifragmentation involving cosmic rays.

Molecular phylogeny and biogeography of the arctic‐alpine genus Lagotis (Plantaginaceae)

AbstractIt has been suggested that many plants now found in the arctic originated from ancestors that occurred at high altitudes in the southern mountains of the Northern Hemisphere during the Tertiary. However, this hypothesis has rarely been tested using a molecular phylogenetic approach. Here, we present a fossil‐calibrated molecular phylogeny of Lagotis, an arctic‐alpine genus with the greatest diversity in the Qinghai‐Tibetan Plateau (QTP) and Central Asian mountains, based on five chloroplast (matK, psbA‐trnH, rps16, trnG‐S, trnL‐F) and nuclear ribosomal ITS DNA markers. Within this framework, we infer the ancestral area and biogeographic history of the genus. Four major clades (A–D) within Lagotis were recovered with strong support, which largely correspond to the previous classification of the genus. Within clade A, Lagotis species from QTP were distributed among several subclades, and L. integrifolia from Central Asia was sister to L. glauca and L. minor from the arctic and subarctic region. The Bayesian molecular dating and the ancestral area reconstruction analyses suggested that Lagotis could have originated in the QTP in the Miocene (Tertiary), and that the genus radiated from the Miocene to Pleistocene. The diversification of Lagotis probably took place predominantly in the QTP and it subsequently spread to the Central Asian highlands, followed by northward migration into the arctic. Our results support the hypothesis that the “Central Asiatic Highland Corridor” as an important route for the migration of the flora between the arctic and QTP.

Biosystematic studies on Dactylis L. 2. Personal research. 2.1. Morphological differentiation and occurrence of representatives of the genus Dactylis in Poland. 2.1.3. Distribution of D. glomerata subsp. aschersoniana (Graebn.) Thell. in Poland

In this paper the author presents the distribution of <em>D. g. </em>subsp. <em>aschersoniana </em>(Graebn.) Thell. in 198 localities in Poland. The studies on distribution were based mainly on revision and verification of materials from Polish herbaria. It is stated that subsp. <em>aschersoniana </em>occurs in deciduous forests in lowlands and on plateaus as well as in lower mountain altitudes. Part of the localities are situated beyond the present eastern limit of the <em>Fagus sylvatica </em>distribution. This confirms the opinion that this subspecies is not connected with beech woods but rather with oak-hornbeam forests. Sometimes subsp. <em>glomerata, </em>subsp. <em>slovenica </em>and subsp. <em>aschersoniana </em>were found in one locality. This fact is very important in the context of gene-flow between these three subspecies.

Measurements and Monte Carlo simulations of the spectral variations of the cosmic-ray-induced neutrons at the Pic du Midi over a 2-y period

In this paper, a Bonner Sphere Spectrometer extended to high energies (HERMEIS) was employed to measure continuously the cosmic-ray-induced neutron spectra over a long-term period (2 y) at mountain altitude and medium geomagnetic latitude (Pic du Midi de Bigorre in the French Pyrenees, +2885 m, 5.6 GV). The results showed 1-y sinusoidal oscillations in the integrated fluence rates. The amplitude of these oscillations depends on the neutron energetic domain. The fluence rate of thermal neutrons was 53 % higher in August than that in February. Those of epithermal neutrons with energies between 0.4 eV and 0.1 MeV and evaporation neutrons (from 0.1 to 20 MeV) were ∼25 % higher in the summer than those in the winter. Finally, the cascade neutron fluence rate (>20 MeV) remained quite the same (<10 % variation). To understand the effects of local and seasonal changes in the measurement environment, GEANT4 simulations were performed. The nature of rock and thickness of the snow cover during the winter period (given by meteorological data) were investigated. A reasonable agreement between experiments and calculations was found.

Cosmic ray solar modulation and Forbush decrease analyses based on atmospheric neutron spectrometry at mountain altitude and GEANT4 simulations of extensive air showers

AbstractA Bonner sphere spectrometer extended to high energies (HERMEIS) was set up at the summit of the Pic du Midi de Bigorre in the French Pyrenees (altitude: +2,885 m; geomagnetic cutoff: 5.6 GV) in May 2011. The spectral fluence rate distribution of the cosmic ray induced neutrons was continuously measured over a broad energy range from meV up to several GeV and with a 1 h time resolution. While the Sun's activity was increasing and reaching its 24th maximum in the 11 year solar cycle, some Forbush decreases were observed in the atmospheric secondary radiation at mountain altitude. We investigated the evolution of the cascade fluence rate (i.e., neutrons with energy greater than 20 MeV) during the March 2012 events with a series of strong coronal mass ejections hitting the Earth's magnetosphere. The amplitude of the greatest Forbush decrease peaked at 10%. Then, a simulation work based on the GEANT4 toolkit was carried out to quantify the solar modulation induced on the galactic cosmic ray transportation during these events. We performed calculations of extensive air showers generated by monoenergetic primaries (Hydrogen and Helium nuclei) for several zenith incidences. Hence, a complete database was built and validated. We derived an analytical model to estimate the atmospheric neutron spectrum at the Pic du Midi according to primary spectra which only depend on the solar modulation potential (force field approximation). We compared the solar modulation potentials obtained in March 2012 with the ones derived by the neutron monitor yield method. Finally, a satisfying agreement was found.

Characterization of the Neutron Environment and SEE Investigations at the CERN-EU High Energy Reference Field and at the Pic du Midi

A new platform dedicated to the long-term characterization of the Atmospheric Natural Radiative Environment at mountain altitude (Pic du Midi, +2885 m) is presented. The performance of a high energy neutron spectrometer is established with measurements performed in a realistic neutron field and by comparison with the neutron monitors. A SEE-rate prediction approach is also used on a 90 nm SRAM memory array which was irradiated at CERF and set up at the Pic du Midi during almost one year.

Recovering of the TGE electron and gamma ray energy spectra

Strong electric fields inside thunderclouds give rise to enhanced fluxes of high-energy electrons and, consequently, gamma rays and neutrons. During thunderstorms at Mount Aragats, hundreds of Thunderstorm Ground Enhancements (TGEs) comprising millions of energetic electrons and gamma rays, as well as neutrons, were detected at Aragats Space Environmental Center (ASEC) on 3200 m altitude. Observed large TGE events allow for the first time to measure the energy spectra of electrons and gamma rays well above the cosmic ray background. We describe the methodology of solving cosmic ray physics inverse problem to recover the energy spectra of electrons and gamma rays incident on particle detectors located at mountain altitudes. The energy spectra of the electrons have an exponential shape and extend up to 30-40 MeV. Recovered energy spectra of the gamma rays is also exponential in energy range 5-10 MeV, then turns to power law and is extending up to 100 MeV.

Neutron production during thunderstorms

We have analyzed the neutron fluxes correlated with thunderstorm activity recently measured at mountain altitudes by Tien-Shan, Tibet and Aragats groups. We perform simulations of the photonuclear reactions of gamma rays born in the electron-gamma ray avalanches in the thunderstorm atmosphere and calculate expected count rates of the neutron counters used by 3 groups. Our analysis supported the Tibet group conclusion on the photonuclear nature of thunderstorm-correlated neutrons. The photonuclear reactions of the gamma rays born in the electron-photon avalanches in the thunderstorm atmospheres interacting in the lead producer of a Neutron monitor can provide neutron yield compatible with additional count of NM at least for the largest Thunderstorm Ground Enhancements (TGEs).

Extensive Cloud Showers (ECS) – New High-Energy Phenomena Resulting from the Thunderstorm Atmospheres

We report the phenomenon of the Extensive Cloud Showers (ECS) detected by the surface particle detectors at mountain altitudes in correlation with thunderstorms. Measured microsecond duration particle bursts are first direct evidence of the electron-photon avalanches in the thunderstorm atmospheres, reaching the mountain altitudes from low located thunderclouds. In the report we present analysis of these rare events including spatial distribution, density spectra and particle energy.

Performance test of a large modular cosmic-ray detector

Recently, details of modular cosmic ray detectors developed by the staff of the SVIRCO Observatory and Terrestrial Physics Laboratory (Rome, National Institute for Astrophysics) were published (Signoretti and Storini, 2011). Data recorded during June 2011 by a modular mobile neutron detector, equipped with a large helium counter (5.08 cm in diameter, 191 cm long) and assembled with twenty-three modules, were carefully checked and used to investigate the detector response to the perturbations originating on the Sun and travelling through the interplanetary medium. We show that at the Rome rigidity threshold (about 6.3 GV) the registered intensity well accounts for the macro perturbations in the near-Earth Space. Nevertheless, to investigate the fine structure of the perturbations the modular detector should operate at mountain altitudes or in polar areas.

Analysis of Lateral Distribution of Atmospheric Cherenkov Light at High Mountain Altitude Towards Event Reconstruction

Air shower simulations with CORSIKA6.990 code using FLUKA 2011 and QGSJET II hadron generators are performed. The simulations are carried out at high mountain observation level, namely, Chacaltaya cosmic ray station. The lateral distribution of atmospheric Cherenkov light produced by various primary particles, namely, proton, helium, oxygen, and iron nuclei, is obtained over wide energy range, between 1011 eV and 1017 eV. The lateral distribution is obtained, integrating over time and angle Cherenkov photons till 800 m from the shower axis. The shapes of the obtained distributions are compared and parameterized. Three different approximations of lateral distribution of Cherenkov light are compared. On the basis of inverse problem solution an event analysis, towards mass composition and energy reconstruction of the primary particle, is carried out. The applications and scientific potential for HECRE experiment proposal are discussed.

Remarks on recent results on neutron production during thunderstorms

We analyze the neutron fluxes correlated with thunderstorm activity recently measured at mountain altitudes by the Tien-Shan, Tibet, and Aragats groups. We perform simulations of the photonuclear reactions of gamma rays born in the electron-gamma ray avalanches and calculate the expected count rates of the neutron detectors used by the three groups. We also present results of an independent experiment performed at the Nor Amberd high altitude research station in Armenia. Our analysis supports the Tibet and Aragats groups' conclusions on the photonuclear nature of thunderstorm-correlated neutrons (directly in the neutron monitor and in the atmosphere). The photonuclear reactions of the gamma rays born in the electron-photon avalanches in the thunderstorm atmospheres interacting with the air atoms and with lead producer of a neutron monitor can provide neutron yield compatible with additional count of neutron monitors registered during thunderstorm ground enhancements.

Experimental Measurements of the Cosmic-Ray Induced Neutron Spectra at Various Mountain Altitudes With HERMEIS

Measurements performed with the High Energy Range Multisphere Extended IRSN System (HERMEIS) acquired by the French Aerospace Lab are presented and discussed. The detectors were calibrated at the Low Noise Underground Laboratory of Rustrel. Atmospheric neutron spectra were obtained at three altitudes ( ${+}500$ m, ${+}1000$ m and ${+}2885$ m) and the first results about the continuous measurements of the Natural Radiative Environment at the Pic du Midi are presented with a discussion about the uncertainties.

Emulsion chamber observations of Centauros, aligned events and the long-flying component

Abstract The cosmic ray emulsion chamber community has reported several unusual phenomena which are also relevant to experiments at the current high-energy accelerators, in particular the Fermilab Tevatron Collider and the CERN Large Hadron Collider (LHC). A summary of the ”Cosmic Rays at Mountain Altitude” workshop held at Plock (Poland, September 2010) is given.

Quaternary glacier development and the relationship between the climate change and tectonic uplift in the Helan Mountain

Isolated NE-SW stretching the Helan Mountain massif, separating the temperate grassland of the Ordos plateau from the Tenggeli Desert, is a key position of studying the glacier development in west China as well as the coupling conditions of climate change with tectonic uplift. The glacial landforms and deposits including cirques, peaks, knife-edge ridges, lateral moraines, and terminal moraines distribute above 2800 m a.s.l. in the middle part of the Helan Mountain. This distribution indicates that here was once glaciated during the late Quaternary. Morphology features show a clear sequence of landscape forming events took place throughout the Helan Mountain. Laboratory optically stimulated luminescence (OSL) and accelerator mass spectrometry radiocarbon dating (AMS 14C) results indicate a late history of glacial advance. Late Pleistocene glaciers in the middle part of the Helan Mountain advanced to near their positions at least four times, and the glacial sequences can be assigned as the middle stage of last glacial cycle (MIS3b, 43.2±4.0 ka), last glacial maximum (LGM, ∼18 ka), late glacial (12.0±1.1 ka) and neo-glacial (3.4±0.3 ka) respectively. Adopting equilibrium line altitude ∼2980 m of last glacial maximum and the modern theoretical snowline altitude ∼4724 m as the maximum amplitudes, and the standard marine isotope curve (MIS) as the glacial equilibrium line change since the Gonghe Movement (150 ka), the relationship between the mountain altitude and glacier development is discussed herein. Compared with other environmental indexes such as the loess-paleosol and ice core, conclusions are made that glacier advances in the Helan Mountain during the late Quaternary obviously depended on the coupled control of tectonic uplift of mountain with the climate condition. It is at last glaciation that the mountain reached the altitude above snowline and coupled with the glacial climate. The glacial advances occurred in the early and middle stages of last glacial cycle after the Gonghe Movement.

A new species of Callistethus from Mexico (Coleoptera, Melolonthidae, Rutelinae)

Callistethus tlapanecus, a new species collected in pine forest located at 2160 meters of altitude in eastern mountains of the state of Guerrero, Mexico is described. The morphological characters that distinguish it from other Mexican and Central American species are discussed. The diagnostic characters are illustrated, and a key to Mexican species of Callistethus is also included.