Aim Pleistocene erratic boulders are rocks that were relocated by glaciers during the Ice Ages. When their geology differs from of landscape surrounds them, form habitat islands for regionally rare, edaphically specialised, rock-dwelling cryptogams (bryophytes, ferns and lichens). Such constitute terrestrial model systems exploring island biogeographic predictions effect environmental variables...

This report includes the clinical, radiological, morbid anatomical, and histological findings in the lungs of a man who for a continuous period of 45 years had been engaged in the loading and unloading of coal in ships and trains. He presented as a case of congestive cardiac failure with signs of severe pulmonary hypertension. The chief feature in the lungs was the presence of silicoticlike nod...

An integrated nomenclature scheme is proposed to capture the inherent heterogeneity of fine-grained sedimentary rocks at the 102 to 1023 mm scale and to assist the evaluation of these rocks as sinks of organic carbon, barriers to fluid flows, and reservoirs of oil and gas. This scheme incorporates previous knowledge and the latest field, petrographic, and laboratory observations. We propose to ...

The composition of Mars' crust records the planet's integrated geologic history and provides clues to its differentiation. Spacecraft and meteorite data now provide a global view of the chemistry of the igneous crust that can be used to assess this history. Surface rocks on Mars are dominantly tholeiitic basalts formed by extensive partial melting and are not highly weathered. Siliceous or calc...

The relationships of the sponge classes are controversial, particularly between the calcareous and siliceous sponges. Specimens of the putative calcarean Eiffelia globosa Walcott from the Burgess Shale show the presence of diagnostic hexactinellid spicules integrated into the skeletal mesh. The arrangement of these spicules in Eiffelia is shown to be precisely equivalent to that of early protos...

Creating lightweight, mechanically robust materials has long been an engineering pursuit. Many siliceous skeleton species--such as diatoms, sea sponges and radiolarians--have remarkably high strengths when compared with man-made materials of the same composition, yet are able to remain lightweight and porous. It has been suggested that these properties arise from the hierarchical arrangement of...

A siliceous mesocellular foam-immobilized Ru-TsDPEN complex exhibited excellent catalytic reactivity, enantioselectivity and reusability in the asymmetric transfer hydrogenation of an imine and ketones.

Biosilicification is widespread across the eukaryotes and requires concentration of silicon in intracellular vesicles. Knowledge of the molecular mechanisms underlying this process remains limited, with unrelated silicon-transporting proteins found in the eukaryotic clades previously studied. Here, we report the identification of silicon transporter (SIT)-type genes from the siliceous loricate ...