University of Iceland

About: University of Iceland is a education organization based out in Reykjavik, Suðurnes, Iceland. It is known for research contribution in the topics: Population & Genome-wide association study. The organization has 5423 authors who have published 16199 publications receiving 694762 citations. The organization is also known as: Háskóli Íslands.

The thermal regime of sub-polar glaciers mapped by multi-frequency radio-echo sounding

Abstract: Radio-echo soundings provide an effective tool for mapping the thermal regimes of polythermal glaciers on a regional scale Radar signals of 320–370 MHz penetrate ice at sub-freezing temperatures but are reflected from the top of layers of ice which are at the melting point and contain water Radar signals of 5–20 MHz, on the other hand, see through both the cold and the temperate ice down to the glacier bed Radio-echo soundings at these frequencies have been used to investigate the thermal regimes of four polythermal glaciers in Svalbard: Kongsvegen, Uversbreen, Midre Lovenbreen and Austre Broggerbreen In the ablation area of Kongsvegen, a cold surface layer (50–160 m thick) was underlain by a warm basal layer which is advected from the temperate accumulation area The surface ablation of this cold layer may be compensated by freezing at its lower cold-temperate interface This requires that the free water content in the ice at the freezing interface is about 1 % of the volume The cold surface layer is thicker beneath medial moraines and where cold-based hanging glaciers enter the main ice stream On Uversbreen the thermal regime was similar to that of Kongsvegen A temperate hole was found in the otherwise cold surface layer of the ablation area in a surface depression between Kongsvegen and Uversbreen where meltwater accumulates during the summer (near the subglacial lake Setevatnet, 250 m asl) Lovenbreen w as frozen to the bed at the snout and along all the mountain slopes but beneath the central part of the glacier a warm basal layer (up to 50 m thick) was fed by temperate ice from two cirques On Austre Broggerbreen, a temperate basal layer was not detected by radio-echo soundings but the basal ice was observed to be at the melting point in two boreholes

Ontogeny of trophic morphology in four sympatric morphs of arctic charr Salvelinus alpinus in Thingvallavatn, Iceland

Abstract: Four coexisting morphs or arctic charr, Salvelinus alpinus (L.), occur in the lake Thingvallavatn, Iceland. They can be identified by their head morphology, which appears to he related to feeding habits, benthivorous or planktivorous-piscivorous. Laboratory-rearing experiments indicate that these morphological differences have a genetic basis with a significant maternal effect and support the suggestion that there are three populations of arctic charr in the lake. The ontogenetic mechanism of these differences most readily explained as development heterochrony, that is the heterochrony that shape reflects embryonic phenotypic characteristics while the planktivorous-piscivorous head shape is more differentiated from the embroyonic phenotype.

Antimicrobial peptides important in innate immunity.

Abstract: Antimicrobial peptides are present in all walks of life, from plants to animals, and they are considered to be endogenous antibiotics. In general, antimicrobial peptides are determinants of the composition of the microbiota and they function to fend off microbes and prevent infections. Antimicrobial peptides eliminate micro-organisms through disruption of their cell membranes. Their importance in human immunity, and in health as well as disease, has only recently been appreciated. The present review provides an introduction to the field of antimicrobial peptides in general and discusses two of the major classes of mammalian antimicrobial peptides: the defensins and the cathelicidins. The review focuses on their structures, their main modes of action and their regulation.

A Dynamic Model of Rift Zone Petrogenesis and the Regional Petrology of Iceland

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