Search results for "mars"
showing 10 items of 384 documents
Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater
2005
The cover shows part of the Larry's Lookout panorama, seen from the Mars Exploration Rover (MER) Spirit during its drive up Husband Hill: the summit is about 200 metres from the rover. Six papers this week report in detail on the MER mission. An Analysis compares predictions used to select a landing site with the conditions actually encountered. This ‘ground truth’ will be invaluable for interpreting future remote-sensing data. Surface chemistry suggests that the upper layer of soil may contain 1% meteoritic material. MER provides a unique glimpse of solar transits of the moons Phobos and Deimos. Rover Opportunity examined wind-related processes, and spectroscopy indicates a dry origin for …
Gully Erosion Susceptibility Mapping Using Multivariate Adaptive Regression Splines—Replications and Sample Size Scenarios
2019
Soil erosion is a serious problem affecting numerous countries, especially, gully erosion. In the current research, GIS techniques and MARS (Multivariate Adaptive Regression Splines) algorithm were considered to evaluate gully erosion susceptibility mapping among others. The study was conducted in a specific section of the Gorganroud Watershed in Golestan Province (Northern Iran), covering 2142.64 km2 which is intensely influenced by gully erosion. First, Google Earth images, field surveys, and national reports were used to provide a gully-hedcut evaluation map consisting of 307 gully-hedcut points. Eighteen gully erosion conditioning factors including significant geoenvironmental and morph…
Microbiological and chemical monitoring of Marsala base wine obtained by spontaneous fermentation during large-scale production
2014
The present work was undertaken to evaluate the effect of natural wine making on the microbial and chemical composition of Marsala base wine. To this purpose, a large-scale vinification process of Grillo grape cultivar was monitored from the grape harvest to the final product. Total yeasts (TY) showed a rapid increase after must pressings and reached values that were almost identical to those registered during conventional wine makings. Lactic acid bacteria (LAB) were registered at the highest levels simultaneous to those of yeast growth at the beginning of the process. Saccharomyces cerevisiae was the species found at the highest concentrations in all samples analysed. Several strains (n =…
Zvaigžņotā Debess: 2009, Vasara (204)
2009
Contents: E.Conners. The Trojan Asteroids ; V.Šmēlings. Men on the Moon! ; E.Bervalds. Astronomical Domes and “Sauna” ; Z.Alksne, A.Alksnis. Sakurai’s Object Fails to Escape Own Dust ; Z.Alksne, A.Alksnis. R CrB Stars Surrounded by Dust Clouds ; M.Gills. April Started with Astronomy ; A.Alksnis. First Stamps Dedicated to Astronomy by Latvia’s Post-Office ; I.Pundure. Arturs Balklavs and Astronomy of Latvia (till 1969) ; M.Sudārs. Satellite Collisions – What Threat Do They Pose? ; I.Vilks. Dwarf Planets Names in Latvian ; Announcement on the 2nd International Symposium on Dark-sky Parks: 14-19 September 2009, Slovenia ; A.Andžāns. The Best Way to Fight Darkness Is to Switch on Light (Intervi…
Zvaigžņotā Debess: 2008, Vasara
2008
Latvijas Zinātņu akadēmija, Latvijas Universitāte
Lāčplēša tēma latviešu apziņā, literatūrā, mākslā un LU mācībspēku pētījumos
2022
Atzīmējot Andreja Pumpura eposa “Lāčplēsis” 135. gadadienu, kas aprit 2023. gada jūnijā, Humanitāro zinātņu bibliotēkā tika izveidota izstāde "Lāčplēša tēma latviešu apziņā, literatūrā, mākslā un LU mācībspēku pētījumos". Eposs tika publicēts 1888. gada jūnijā saistībā ar Trešo Vispārējo latviešu dziesmu svētku norisēm. Darbs tapis, sintezējot teikas, pasakas un laikabiedru priekšstatus par senatni, saskaņā ar 19. gs. nacionālā romantisma idejām Eiropā laikā, kad eposa esamība tika uztverta kā nācijas eksistences apliecinājums. Izstāde izkārtota 4 plauktos. Pirmajā plauktā izstādīts eposa 1888.gada izdevums. Otrajā plauktā redzami Latvijas Universitātes mācībspēku pētījumi, skatot Lāčplēsi …
Zvaigžņotā Debess: 2004, Rudens (185)
2004
Contents: L.Kondraševa and I.Zimina. New Riga Planetarium ; I.Rabinovičs. Remembering Fricis Blumbahs ; N.Cimahoviča. 50 cm Reflector Constructed in Riga ; J.Tambergs. Problems of Dialogue between Quantum Mechanics and Theology. A.Alksnis, Z.Alksne. The Sloan Great Wall ; A.Balklavs. Radio Galaxy – Emitter of Very High Energy Gamma-Rays ; A.Balklavs. Cosmic Objects in Photos – 2 ; A.Balklavs. New Assessments of Fine-Structure Constant Variability ; N.Cimahoviča. Dark Electric Matter Objects Around Us ; A.Balklavs. New Data on the Solar Granulation ; J.Jaunbergs. The Sinking Cliffs on Io ; D.Krieviņš. Space Launchers of Early XXI Century ; M.Sudārs. SpaceShipOne Closest to X-Prize ; J.Harja.…
Zvaigžņotā Debess: 2007, Rudens
2007
Latvijas Zinātnes padome, Latvijas Universitāte
Zvaigžņotā Debess: 2012/13, Ziema (218)
2012
Saturs: Dienas kārtībā – «melnie caurumi» ; «Pioneer-10» dodas uz Jupiteru ; A.Alksnis. Dīvains miglājs, kam daudz nosaukumu ; M.Ņečajeva, I.Šmelds. Jonosfēras pētījumi Ventspils Starptautiskajā radioastronomijas centrā ; L.Gulbe. Satelīts ne tikai televīzijai, bet arī mežu uzraudzībai ; I.Ķešāns. Nīls Ārmstrongs ; Pirmo reizi “ZvD”: Ints Ķešāns ; E.Bervalds. Par Jāņa Ikaunieka iecerēm un VSRC (nobeigums) ; J.Dambītis, A.Cibulis. Ievērojamais Latvijas matemātiķis Arvīds Lūsis (1900–1969) ; A.Alksnis. LVU astronomijas specialitātes studenti – 1952. gada diplomandi (3.turpin.) ; I.D., I.P. Šoziem atceramies: Arturs Balklavs-Grīnhofs (2.I 1933.) – 80, Ernests Grasbergs (8.III 1938.) – 75 ; K.Š…
Une approche géométrique du contrôle optimal de l'arc atmosphérique de la navette spatiale
2002
L'objectif de ce travail est de faire quelques remarques géométriques et des calculs préliminaires pour construire l'arc atmosphérique optimal d'une navette spatiale (problème de rentrée sur Terre ou programme d'exploration de Mars). Le système décrivant les trajectoires est de dimension 6, le contrôle est l'angle de gîte cinématique et le coût est l'intégrale du flux thermique. Par ailleurs il y a des contraintes sur l'état (flux thermique, accélération normale et pression dynamique). Notre étude est essentiellement géométrique et fondée sur une évaluation de l'ensemble des états accessibles en tenant compte des contraintes sur l'état. On esquisse une analyse des extrémales du Principe du …