Fast flowing ice streams and outlet glaciers provide the major avenues for ice flow from past and present ice sheets. These ice streams move faster than the surrounding ice sheet by a factor of one hundred or more. Several mechanisms for fast ice stream flow have been identified, leading to a spectrum of different ice stream types. In this paper we discuss the two end members of this spectrum, ...

Abstract. Boreal forests in permafrost regions make up around one-third of the global forest cover and are an essential component regional climate patterns. Further, climatic change can trigger extensive ecosystem shifts such as partial disappearance near-surface or changes to vegetation structure composition. Therefore, our aim is understand how interactions between vegetation, atmosphere stab...

The present pattern of British Agriculture has been determined by the physical factors of climate, soil and topography, on which are superimposed technical and economic factors. In considering the potential for change we must work within the physical limitations, assume that an optimum balance of food nutrients supplied by home agriculture could be defined and that economic restraints would be ...

introduction: complicated crown- root fractures, extended caries and iatrogenic destruction often result in insufficient sound tooth structures and compromise the biologic width. two common options for re-establishing flap with osseous surgery. although some advantages are related to these two options, but coronal movement of gingival and alveolar bone in orthodontic extrusion, esthetic problem...

Agrobacterium rhizogenes (pRi), a causative agent of hairy root disease, effectively induces hairy root formation in a variety of plant species. In our study four bacterial strains AR15834, A4, 9435 and C318 and three explants types leaf, stems and roots, were examined. Hairy roots were induced from roots, stems and leaf explants. The highest transformation efficiency of 77% was achieved by usi...

Molecular analysis of grassland rhizosphere soil has demonstrated complex and diverse bacterial communities, with resultant difficulties in detecting links between plant and bacterial communities. These studies have, however, analyzed "bulk" rhizosphere soil, rather than rhizoplane communities, which interact most closely with plants through utilization of root exudates. The aim of this study w...

The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, an...

The retreat of cliffs may constitute the dominant erosional response to base‐level fall in arid settings underlain by horizontally‐bedded sedimentary rock. These vertical cliffs typically loom above a relatively straight bedrock slope (‘plinth’) that is mantled with a thin layer of sediment and perched near the angle of repose. In detail, a plinth consists of a system of quasi‐parallel ridges a...