Search results for "RF"
showing 10 items of 23683 documents
Szwabowie przeciwko Normanom w bitwie pod Civitate w 1053 r. Pomiędzy skandynawską a bizantyńską sztuką prowadzenia wojny
2017
The Battle of Civitate in 1053 was the clash of two worlds. On the one hand, the people of Italy, who defended the old status quo, led by Pope Leo IX. These descendants of the Lombards and the ancient Romans, stand in front of the descendants of the Danes and Norwegians, who earlier created state later called Normandy. The Normans were the new factor, which disrupted the fragile balance of forces in the Mezzogiorno, between the world of Latin, the Greeks, and Islam. The nwecomers from the north of France, only nominally resembled their pedecessors from Scandinavia, representing a new school of warfare, in which they in a kind of synthesis combined the world of the Vikings and the Carolingia…
Neorganisko jonu ietekme uz jonu apmaiņas ekstrahentu adsorbciju uz fāžu robežvirsmām starp ūdens un organiskiem šķīdumiem
2000
Pilsētvides ietekme uz Jāņupītes hidroķīmisko kvalitāti
2015
Bakalaura darbs ir veltīts urbānās vides ietekmei uz ūdenstecēm. Darba tēma ir “Pilsētvides ietekme uz Jāņupītes hidroķīmisko kvalitāti”. Darbā aplūkota zemes lietojumu veida, apbūves - ietekme gan uz Jāņupītes kvalitāti, gan ūdens sastāvu, kas caur to nokļūst Daugavā. Tā kā upe atrodas Krāslavas centrā, tai ir būtiska ietekme uz pilsētas ainavu. Darba mērķis ir noteikt urbānās vides ietekmi uz Jāņupītes ķīmisko sastāvu. Bakalaura darbā ir sniegts upes un tai blakus esošās teritorijas apraksts, literatūras apskats par pilsētu ietekmi uz upju ekosistēmām un vispārējiem kvalitātes rādītājiem, kas noteikti ūdenstecēm, par tēmu veikto pētījumu apskats.
Late Jurassic (Kimmeridgian–Tithonian) stable isotopes (δ18O, δ13C) and Mg/Ca ratios: New palaeoclimate data from Helmsdale, northeast Scotland
2010
Abstract The data presented here provide the first detailed stable isotope ( δ 18 O, δ 13 C) and geochemical (Mg/Ca) investigation of Kimmeridgian–Tithonian belemnites from the Helmsdale Coast, Scotland, UK. Oxygen and carbon stable isotope values from well preserved specimens range from − 2.8 to + 0.3‰ and from − 2.3 to + 2.8‰ respectively. The oxygen isotope data are consistent with palaeotemperatures of up to 24 °C in the Early Kimmeridgian cymodoce Zone and down to 11 °C in the Mid Tithonian rotunda–fittoni Zones. These estimates are strongly supported by the Mg/Ca data, which also indicate a cooling episode (and very similar palaeotemperatures, 11–22 °C) at this time. The cooling event…
A 2600-year record of past polycyclic aromatic hydrocarbons (PAHs) deposition at Holzmaar (Eifel, Germany)
2014
Polycyclic aromatic hydrocarbons (PAHs) are a proxy for climate- and human-related historical fire activity which has rarely been used beyond 1800 AD. We explored the concentration and composition patterns of PAHs together with other proxies (charcoal, C, N, S, δ13C, δ15N, and δ34S) in a sediment core of Holzmaar as indicators of variations in climate and anthropogenic activity over the past 2600 years. The concentrations of pyrogenic PAHs remained low (< 500 ng g− 1) from the pre-Roman Iron Age (600 BC) until the first significant increases to ca. 1000–1800 ng g− 1 between 1700 and 1750 AD related to regional iron production. The highest increases in pyrogenic PAH concentrations occurred w…
Unraveling environmental histories from skeletal diaries — Advances in sclerochronology
2013
High-resolution proxy archives from aquatic settings are essential to better understand processes and mechanisms of global change. During the last decade, it has become increasingly evident that calcified tissues of bivalve mollusks and cold-water corals, in particular, can significantly increase our knowledge of seasonal to multi-decadal paleoclimate and paleoenvironmental variability in the extratropical oceans and coastal marine settings. Daily, tidal, fortnightly and annual growth patterns of periodically formed skeletal hard parts provide a means to place the proxy record in a precise temporal context. Their extreme longevity coupled with the running similarity between growth increment…
Variation in Sr uptake in the shell of the freshwater gastropod Bithynia tentaculata from Lake Arreo (northern Spain) and culture experiments
2010
The Sr uptake features in Bithynia tentaculata aragonite shells from monthly collections in Lake Arreo (northern Spain) over a two-year period are compared with those from the same species grown in culture experiments with similar waters under controlled temperature. The shell aragonite of B. tentaculata from Lake Arreo formed in isotopic equilibrium with the lake water. A comparison of the stable oxygen isotope values (δ18O) from the shells and waters allowed the selection of suitable shells for Sr uptake studies. The Sr/Ca molar ratio in B. tentaculata shells (Sr/Cashell) from the lake and from the culture experiments positively correlate with some chemical parameters like conductivity an…
Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period
2016
This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resol…