Search results for "altitud"

The map of biodiversity : from local to global scales

2018

Species richness is not homogeneous in space and it normally presents differences when comparing among different sites. These differences often respond to gradients in one or several factors which create biodiversity patterns in space and are scale-dependent. At a local scale, diversity patterns depend on the habitat size (species-area relationship), the productivity, the environmental harshness, the frequency and intensity of disturbance, or the regional species pool. Regional diversity may be influenced by environmental heterogeneity (increasing dissimilarity), although it could act also at smaller or larger spatial scales, and the connectivity among habitats. Finally, at a global scale, …

Reduction of olfactory sensitivity during normobaric hypoxia.

2018

Abstract Objective Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500 m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia. Methods Sixteen healthy subjects were assessed using the Sniffin’ Sticks, as well as intensity and pleasantness ratings. Gustatory function was evaluated utilizing the Taste Strips. Experiments were carried out under baseline conditions (518 m altitude) followed by a second testing session after seven hours of normobaric hypoxia exposure (comparable to 4000 m altitude). Results During normobaric hypoxia ol…

Fasciola hepatica phenotypic characterization in Andean human endemic areas: Valley versus altiplanic patterns analysed in liver flukes from sheep fr…

2011

Fascioliasis is a zoonotic parasitic disease caused by Fasciola hepatica and Fasciola gigantica. Of both species, F. hepatica is the only one described in the Americas, mainly transmitted by lymnaeid snail vectors of the Galba/. Fossaria group. Human fascioliasis endemic areas are mainly located in high altitude areas of Andean countries. Given the necessity to characterize F. hepatica populations involved, the phenotypic features of fasciolid adults infecting sheep present in human fascioliasis endemic areas were analysed in the Cajamarca Valley and Mantaro Valley (valley transmission patterns) and the northern Bolivian Altiplano (altiplanic transmission pattern). A computer image analysis…

Depletion of ozone and reservoir species of chlorine and nitrogen oxide in the lower Antarctic polar vortex measured from aircraft

2017

Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases up to ∼40% (0.8 ppbv) at 12 km to 1…

Production altitude and time delays of the terrestrial gamma flashes: Revisiting the Burst and Transient Source Experiment spectra

2008

[1] On the basis of the RHESSI results it has been suggested that terrestrial gamma flashes (TGFs) are produced at very low altitudes. On the other hand some of the Burst and Transient Source Experiment (BATSE) spectra show unabsorbed fluxes of X rays in the 25–50 keV energy range, indicating a higher production altitude. To investigate this, we have developed a Monte Carlo code for X-ray propagation through the atmosphere. The most important features seen in the modeled spectra are (1) a low-energy cutoff which moves to lower energies as TGFs are produced at higher altitudes, (2) a high-energy cutoff which moves to lower energies as TGFs are observed at larger zenith angles, and (3) time d…

Possible Role of Glymphatic System of the Brain in the Pathogenesis of High-Altitude Cerebral Edema

2018

Simka, Marian, Paweł Latacz, and Joanna Czaja. Possible role of glymphatic system of the brain in the pathogenesis of high-altitude cerebral edema. High Alt Med Biol. 19:394–397, 2018.—In this article, we suggest that the glymphatic system of the brain can play an important role in the pathogenesis of high-altitude cerebral edema (HACE). Water enters the intercellular space of the brain primarily through aquaporin-4 (AQP-4) water channels, the main component of the glymphatic system, whereas acetazolamide, pharmacological agent used in the prevention of HACE, is the blocker of the AQP-4 molecule. In animal experiments, cerebral edema caused by hypobaric hypoxia was associated with an increa…

PHYTOSEIIDAE (ACARI: PARASITIFORMES) OF SICILY (ITALY): SPECIES DIVERSITY AFTER HALF A CENTURY OF SURVEYS

2020

Gli acari fitoseiidi sono divenuti interesse di studio in Sicilia a partire dai primi anni '70. Ricerche costanti nel tempo hanno arricchito le conoscenze sulla fauna siciliana con la segnalazione di 48 specie valide, cinque delle quali nuove per la Scienza. Nel presente lavoro riassumiamo i dati raccolti in circa cinquant'anni, con l’aggiunta di 12 nuove segnalazioni per la fauna isolana. Typhlodromus (Anthoseius) cryptus Athias-Henriot   stata confermata la specie pi  frequente (39,4%), seguita da Typhlodromus (Typhlodromus) exhilaratus Ragusa (32,6%), Kampimodromus aberrans (Oudemans) (22,9%), Typhlodromus (Anthoseius) rhenanoides Athias-Henriot (19,4%) (18,9%). Alcune specie hanno mostr…

The geography of hybrid speciation in plants

2015

High Arctic aircraft measurements characterising black carbon vertical variability in spring and summer

2019

The vertical distribution of black carbon (BC) particles in the Arctic atmosphere is one of the key parameters controlling their radiative forcing and thus role in Arctic climate change. This work investigates the presence and properties of these light-absorbing aerosols over the High Canadian Arctic (>70∘ N). Airborne campaigns were performed as part of the NETCARE project (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) and provided insights into the variability of the vertical distributions of BC particles in summer 2014 and spring 2015. The observation periods covered evolutions of cyclonic disturbances at the polar front, which f…

Bioaerosols in the Amazon rain forest: temporal variations and vertical profiles of Eukarya, Bacteria, and Archaea

2021

The Amazon rain forest plays a major role in global hydrological cycling, and biogenic aerosols are likely to influence the formation of clouds and precipitation. Information about the sources and altitude profiles of primary biological aerosol particles, however, is sparse. We used fluorescence in situ hybridization (FISH), a molecular biological staining technique largely unexplored in aerosol research, to investigate the sources and spatiotemporal distribution of Amazonian bioaerosols on the domain level. We found wet season bioaerosol number concentrations in the range of 1–5 × 105 m−3 accounting for > 70 % of the coarse mode aerosol. Eukaryotic and bacterial particles predominated, …