Search results for "Continent"
showing 10 items of 598 documents
Ancient human genomes suggest three ancestral populations for present-day Europeans
2014
We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes1,2,3,4 with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians3, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these popula…
Analyses of phase change materials’ efficiency in warm-summer humid continental climate conditions
2017
The usage of phase change materials (PCMs) is a way to store excess energy pro- duced during the hot time of the day and release it during the night thereby reducing the overheating problem. While, in Latvian climate conditions overheating is not a big issue in traditional buildings since it happens only a couple of weeks per year air conditioners must still be installed to maintain thermal comfort. The need for cooling in recently built office buildings with large window area can increase signi cantly. It is therefore of great interest if the ther- mal comfort conditions can be maintained by PCMs alone or with reduced maximum power of installed cooling systems. Our initial studies show tha…
Experimental testing of phase change materials in a warm-summer humid continental climate
2019
Abstract The construction industry (and buildings) is one of the largest energy consuming and CO2 emitting sectors in the world. To counter this, more lightweight structures are being used and energy saving applications are being developed. Phase change materials (PCM) are materials that can be considered to tackle these new challenges. It has been proven that PCMs can be passively used to improve the thermal mass of lightweight structures, which improves thermal comfort and reduces peak cooling and heating loads and therefore provides energy savings. To use these materials in an active way, they should be used together with ventilation, cooling or heating equipment, and collectors to accum…
Biohydrology: coupling biology and soil hydrology from pores to landscapes
2010
The articles in this issue are a selection of the presentations made at the 2nd International Conference of Biohydrology. This special issue ‘Biohydrology—coupling biology and soil hydrology from pores to landscapes’ contains a range of articles on biological and hydrological interactions in soil, including large-scale systems research on the influence of forests on catchments and small-scale reductionist research on processes operating at the scale of soil pores. Copyright 2010 John Wiley & Sons, Ltd.
A conceptual dynamic vegetation-soil model for arid and semiarid zones
2007
Plant ecosystems in arid and semiarid zones show high complexity from the point of view of water resources, since they depend on water availability to carry out their vital processes. In these climates, water stress is the main factor controlling vegetation development. The available water in the system results from a water balance where the soil, vegetation and the atmosphere are the key issues; but it is the vegetation which modulates (to a great extent) the total balance of water and the mechanisms of the feedback between soil and atmosphere, being the knowledge about soil moisture quite relevant for assessing available water and, as a consequence, for growth and plants maintenance and t…
Les Hypogées d'Arles-Fontvieille et leur environnement : nouvelles perceptions, nouvelles perspectives
2014
Due to their unique architecture and the exceptional dimensions of the largest monument in the group, the Arles-Fontvieille hypogea are among the most remarkable megalithic monuments in Europe and the western Mediterranean region. A collective research program was launched in 2013 to study these well-known monuments which have, paradoxically, been the subject of relatively few field studies since the 19th century. The research program consisted of an inventory and analysis of the grave goods and associated artefacts, as well as a number of field studies providing an improved archaeological context of a megalithic group too often thought of only in terms of funerary monuments. Various traces…
Geochemistry, zircon U–Pb ages and Lu–Hf isotopes of early Paleozoic plutons in the northwestern Chinese Tianshan: Petrogenesis and geological implic…
2013
Abstract The northwestern Chinese Tianshan is a key part of the southern Central Asian Orogenic Belt. Voluminous arc-related igneous rocks in this region have recorded the opening and closure of several oceanic basins that may represent southern branches of the Paleo-Asian Ocean. We have conducted geochemical, geochronological and Hf-in-zircon isotopic studies on mafic and felsic intrusive rocks in the northwestern Chinese Tianshan to provide important clues for the evolution of the Junggar Ocean and to understand the early Paleozoic crustal growth in the Central Asian Orogenic Belt. The mafic plutons are composed of metagabbro (453.8 ± 2.0 Ma) and fine-grained diorite (461.1 ± 2.0 Ma). The…
Primary Frequency Control in the Power System of Continental Europe including the Dynamics of the HVDC Link France-Great Britain
2020
The paper presents a study of primary frequency control within the power system of Continental Europe (CE) including the dynamics of the high voltage direct current (HVDC) link between France and Great Britain (GB). The large-scale dynamic model of the CE system originally provided by ENTSO-E is extended with a more detailed representation of the whole HVDC interconnection. The dynamics of the GB synchronous area is also considered in the analysis, implementing a system equivalent suitable for primary frequency control studies. The opportunity of frequency containment reserve exchange between the two areas through the link is also investigated, considering supplementary frequency controls w…
Additions to knowledge of the biodiversity of benthic hydroids (Cnidaria: Hydrozoa) in the Balleny Islands (Antarctica)
2021
The Balleny Islands, an isolated archipelago located 240 km off the coast of Victoria Land (East Antarctica), are separated from the Antarctic continental shelf by waters more than 2000 m deep. The benthic hydroid fauna of these islands is little known, with only 25 species reported so far. The present study contributes to a better knowledge of the benthic hydrozoans inhabiting this archipelago by studying a small collection held at the National Institute of Water and Atmospheric Research Invertebrate Collection at Wellington, New Zealand. Sixteen species of benthic hydroids were found in the collection, belonging to nine families and 12 genera of Leptothecata. Kirchenpaueriidae and Oswalde…
Sapphire-bearing magmatic rocks trace the boundary between paleo-continents: A case study of Ilmenogorsky alkaline complex, Uralian collision zone of…
2021
Abstract Metamorphic gem corundum (mainly ruby) deposits are robust indicators of continent-continent collision processes. However, a systematic link of primary magmatic blue sapphire occurrences to orogenic belts is less understood. An example is the Ilmenogorsky alkaline complex, within the Ilmen Mountains region and part of the Uralian orogenic belt. The mobile belt is a product of the collision among Kazakhstania, Laurussia, and Siberia continents prior to the closure of the Paleo-Uralian ocean and formation of the Laurasia supercontinent (330–250 Ma). It is believed that the alkaline complex became inсluded into the separate Sysertsk-Ilmenogorsk microcontinent with unconstrained border…