Search results for "Terrestrial"
showing 10 items of 229 documents
Sogdatawa ǝtumǝciusu
1934
Apskats par zivīm un zvejniecību nanaju (goldu) valodā.
Revealing the pace of river landscape evolution during the Quaternary: recent developments in numerical dating methods
2016
During the last twenty years, several technical developments have considerably intensified the use of numerical dating methods for the Quaternary. The study of fluvial archives has greatly benefited from these enhancements, opening new dating horizons for a range of archives at distinct time scales and thereby providing new insights into previously unanswered questions. In this contribution, we separately present the state of the art of five numerical dating methods that are frequently used in the fluvial context: radiocarbon, Luminescence, Electron Spin Resonance (ESR), 230Th/U and terrestrial cosmogenic nuclides (TCN) dating. We focus on the major recent developments for each technique th…
Whole-lake experiments reveal the fate of terrestrial particulate organic carbon in benthic food webs of shallow lakes
2014
Lake ecosystems are strongly linked to their terrestrial surroundings by material and energy fluxes across ecosystem boundaries. However, the contribution of terrestrial particulate organic carbon (tPOC) from annual leaf fall to lake food webs has not yet been adequately traced and quantified. In this study, we conducted whole-lake experiments to trace artificially added tPOC through the food webs of two shallow lakes of similar eutrophic status, but featuring alternative stable regimes (macrophyte rich vs. phytoplankton dominated). Lakes were divided with a curtain, and maize (Zea mays) leaves were added, as an isotopically distinct tPOC source, into one half of each lake. To estimate the …
Towards a test of the weak equivalence principle of gravity using anti-hydrogen at CERN
2016
International audience; The aim of the GBAR (Gravitational Behavior of Antimatter at Rest) experiment is to measure the free fall acceleration of an antihydrogen atom, in the terrestrial gravitational field at CERN and therefore test the Weak Equivalence Principle with antimatter. The aim is to measure the local gravity with a 1% uncertainty which can be reduced to few parts of 10-3.
Seabird influence on ecological processes in coastal marine ecosystems: An overlooked role? A critical review
2021
Abstract Seabirds are vital, but overlooked, components of coastal marine ecosystems and may connect the marine and terrestrial environment at a global scale, significantly contributing to inter-habitat connectivity and the provision of multiple ecosystem services. Although the ecological and functional role of birds in terrestrial areas, islands in particular, has been deeply studied since the last century, the same does not hold true for coastal marine areas. Given the importance of coastal areas for seabirds worldwide and, at the same time, the high vulnerability of both, looking into the role of seabirds in influencing the ecosystem functioning in coastal areas is needed nowadays. Here,…
Study and 3D survey of the Roman baths in the archaeological site of Lylibaeum (Marsala, Italy)
2020
Abstract Archaeological documentation is a fundamental step for research and conservation planning phases. Nowadays traditional recording is always supported by geomatics technologies which offer important support to the growth of archaeological study. The integration of sensors and methodologies seems to give the best results, in terms of time, costs and accuracy of products. In particular, the combination of Terrestrial Laser Scanner (TLS) and Unmanned Aerial Vehicle (UAV) can help the documentation of complex sites and the production of 3D and 2D products for different purposes. The paper focuses on the integration of TLS and UAV methodologies to record the thermal baths of the Roman Dom…
Basaltic Rocks Analyzed by the Spirit Rover in Gusev Crater
2004
The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and MiniâThermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain â¤25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. MoÌssbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. The…
Mineralogy at Gusev Crater from the Mössbauer spectrometer on the Spirit Rover.
2004
Mössbauer spectra measured on Mars by the Spirit rover during the primary mission are characterized by two ferrous iron doublets (olivine and probably pyroxene) and a ferric iron doublet (tentatively associated to nanophase ferric iron oxide). Two sextets resulting from nonstoichiometric magnetite are also present, except for a coating on the rock Mazatzal, where a hematite-like sextet is present. Greater proportions of ferric-bearing phases are associated with undisturbed soils and rock surfaces as compared to fresh rock surfaces exposed by grinding. The ubiquitous presence of olivine in soil suggests that physical rather than chemical weathering processes currently dominate at Gusev crat…
Magnetic Properties Experiments on the Mars Exploration Rover Spirit at Gusev Crater
2004
The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars—and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of ∼2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit.
Intercomparison of remote-sensing based evapotranspiration algorithms over amazonian forests
2019
Abstract Evapotranspiration (ET) is considered a key variable in the understanding of the Amazonian tropical forests and their response to climate change. Remote-Sensing (RS) based evapotranspiration models are presented as a feasible means in order to provide accurate spatially-distributed ET estimates over this region. In this work, the performance of four commonly used ET RS models was evaluated over Amazonia using Moderate Resolution Imaging Spectroradiometer (MODIS) data. RS models included i) Priestley-Taylor Jet Propulsion Laboratory (PT-JPL), ii) Penman-Monteith MODIS operative parametrization (PM-Mu), iii) Surface Energy Balance System (SEBS), and iv) Satellite Application Facility…