Search results for "Meteor"
showing 10 items of 4734 documents
Biogēno procesu modelēšanas iespēju novērtējums pāraugušās audzēs
2019
Maģistra darbā izstrādāts biogēno procesu norises modelis neskartās, pāraugušās priežu audzēs, kuru iespējams izmantot procesu paredzēšanai nākotnē. Izstrādātais modelis pilnveido zināšanas par mežaudzē notiekošajiem procesiem un atsevišķiem ietekmējošiem faktoriem. Simulācijās izmantoti tādi biogēniskie faktori kā temperatūras, nokrišņu, vēja ātruma un kukaiņu nodarītā kaitējuma izvērtējums. Simulāciju scenāriji izstrādāti pāraugušām priežu audzēm Latvijas teritorijā, kuri izvietoti katrs savā reģionā (kopā 4 pētījumu pilotteritorijas) un atrodas ne tālāk par 50 km no meteoroloģisko novērojumu stacijas. Iegūtie rezultāti liecina, ka pētāmajās mežaudzēs būtiskākais ir tās vecums, bet apskat…
Meteoroloģisko sezonu raksturs un to ilglaicīgās izmaiņas Latvijas teritorijā
2015
Bakalaura darbā „Meteoroloģisko sezonu raksturs un to ilglaicīgās izmaiņas Latvijas teritorijā” ir veikta Latvijas meteoroloģisko sezonu raksturojošo temperatūras rādītāju un to ilgtermiņa izmaiņu analīze. Veicot šo pētījumu, katram gadam periodā no 1950. līdz 2010. gadam tika noteiktas sākuma dienas katrai sezonai desmit Latvijas novērojumu stacijās (NS)- Liepāja, Kolka, Bauska, Saldus, Rēzekne, Rūjiena, Zosēni, Zīlāni, Alūksne un Daugavpils. Literatūras apskatā ir apkopota informācija par sezonalitātes klasifikācijas principiem, dažādiem veidiem, pēc kā noteikt gadalaiku miju. Papildus tam tika apskatīti atmosfēras procesi, kas gada gaitā ietekmē Latvijas klimatu – liela mēroga atmosfēras…
Model, software and database for line-mixing effects in the ν3 and ν4 bands of CH4 and tests using laboratory and planetary measurements-I: N2(and ai…
2006
International audience; Absorption spectra of the infrared ν3 and ν4 bands of CH4 perturbed by N2 over large ranges of pressure and temperature have been measured in the laboratory. A theoretical approach accounting for line mixing is proposed to (successfully) model these experiments. It is similar to that of Pieroni et al. [J Chem Phys 1999;110:7717–32] and is based on state-to-state rotational cross-sections calculated with a semi-classical approach and a few empirical parameters. The latter, which enable switching from the state space to the line space, are deduced from a fit of a single room temperature spectrum of the ν3 band at 50 atm. The comparisons between numerous measured and ca…
Consequences of analgesics use in early pregnancy: Results of tests on mice.
2019
International audience; Self-medication during pregnancy continues to be an issue in developing countries due topoor medical education. The most commonly used drugs are analgesics, mainlyacetaminophen (paracetamol, APAP) and, to a lesser extent, ketoprofen (KPF). The aim of thestudy was to establish whether there are consequences of accidental use of these two drugsduring early embryogenesis. The experimental study was performed on 30 pregnant whitemice, divided into three groups: a first group to which APAP was administered, a secondgroup to which KPF was administered, and group 3 as a control group. At delivery, the babymice were examined, and after their first parturition, they were take…
Applicability of a displaced-beam laser scintillometer in a sparse tall Mediterranean vegetation
2009
Recent studies showed that the sensible heat flux (H) measured with an array of eddy-correlation system has an high spatial and temporal variability over sparse tall vegetation, such as olive trees, whereas H determined with a displaced-beam laser scintillometer (DBLS) appeared to behave more stable. In this study, the results are shown of two field experiments performed over an olive tree plantation in Sicily in 2007 and 2008, in order to investigate the applicability of a DBSL in combination with remote sensing techniques for the actual evapotranspiration assessment. In 2007 the laser beams was closer to the top of the canopy than in 2008. Various aspects of the scintillation method will …
Energy and economic assessment of a small domestic wind turbine in Palermo
2016
The cost effectiveness of micro-wind technology is closely linked to the annual energy production plants, which strongly depends on the wind characteristics and on the morphological properties of the installation site. The power curve of a wind turbine, supplied by manufacturers, characterizes the theoretical energy performance that it should have at a particular site. The behavior of a wind turbine in the field is affected by the speed but also by wind direction variations. At each change of direction and speed, the turbine will try to adapt to new conditions and the phase transition negatively influences the energy production. In order to experimentally confirm what above mentioned, the a…
Formation of microbial organic carbonates during the Late Jurassic from the Northern Tethys (Amu Darya Basin, Uzbekistan): implications for Jurassic …
2020
23 pages; International audience; The Late Jurassic was a period of major global carbon cycle perturbations with episodes of anoxia leading to regional accumulation of organic matter in sediments worldwide. The Tubiegatan section (SW Gissar Mountains, Uzbekistan) located in the Northern Tethys, shows atypical organic-rich limestone and marl deposits (up to 6% of total organic carbon) marked by pronounced negative excursions of δ13Ccarb (amplitude of ca. 12‰) and δ13Corg (amplitude of ca. 4‰) recorded during the Middle Oxfordian (Transversarium Zone). A transdisciplinary approach including sedimentology, palynofacies characterization, mineralogy, organic and inorganic geochemistry was carrie…
Orthogonal switching of AMS axes during type-2 fold interference : Insights from integrated X-ray computed tomography, AMS and 3D petrography
2017
We applied X-ray computed microtomography (μ-CT) in combination with anisotropy of magnetic susceptibility (AMS) analysis to study metamorphic rock fabrics in an oriented drill core sample of pyrite-pyrrhotite-quartz-mica schist. The sample is extracted from the Paleoproterozoic Martimo metasedimentary belt of northern Finland. The μ-CT resolves the spatial distribution, shape and orientation of 25,920 pyrrhotite and 153 pyrite grains localized in mm-thick metapelitic laminae. Together with microstructural analysis, the μ-CT allows us to interpret the prolate symmetry of the AMS ellipsoid and its relationship to the deformation history. AMS of the sample is controlled by pyrrhotite porphyro…
Particle chemical properties in the vertical column based on aircraft observations in the vicinity of Cape Verde Islands
2011
During the second Saharan Mineral Dust Experiment (SAMUM-2) field campaign, particles with geometric diameters (d) between ∼0.1 and 25 μm were collected on board of the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center, DLR) Falcon aircraft. Size, chemical composition and mixing state of aerosols sampled (spatially and vertically resolved) along the West African coastline and in the Cape Verde Islands region were determined by electron microscopy. A pronounced layer structure of biomass-burning aerosol and desert dust was present for all days during the sampling period from 23 January to 6 February. The aerosol composition of the small particles (d < 0.5 μm) was highly v…
Greater mitochondrial energy production provides resistance to ocean acidification in "winning" hermatypic corals
2021
Coral communities around the world are projected to be negatively affected by ocean acidification. Not all coral species will respond in the same manner to rising CO2 levels. Evidence from naturally acidified areas such as CO2 seeps have shown that although a few species are resistant to elevated CO2, most lack sufficient resistance resulting in their decline. This has led to the simple grouping of coral species into “winners” and “losers,” but the physiological traits supporting this ecological assessment are yet to be fully understood. Here using CO2 seeps, in two biogeographically distinct regions, we investigated whether physiological traits related to energy production [mitochondrial e…