Possible glendonite mineral pseudomorphs in the aftermath of the end-Permian extinction.

Glendonites (from the precursor of ikaite, CaCO.6HO) preferentially precipitate within sediments in cold waters (- 2 to 7°C) via either organotrophic or methanogenic sulphate reduction. Here, we report the first occurrence of possible glendonites associated with the end Permian mass extinction in the earliest Triassic (ca.

Bioinspired surface structures for added shear stabilization in suction discs.

Many aquatic organisms utilize suction-based organs to adhere to diverse substrates in unpredictable environments. For multiple fish species, these adhesive discs include a softer disc margin consisting of surface structures called papillae, which stabilize and seal on variable substrates. The size, arrangement, and density of these papillae are quite diverse among different species, generating complex disc patterns produced by these structures.

Natural sampling and aliasing of marine geochemical signals.

It is well known that the sedimentary rock record is both incomplete and biased by spatially highly variable rates of sedimentation. Without absolute age constraints of sufficient resolution, the temporal correlation of spatially disjunct records is therefore problematic and uncertain, but these effects have rarely been analysed quantitatively using signal processing methods. Here we use a computational process model to illustrate and analyse how spatial and temporal geochemical records can be biased by the inherent, heterogenous processes of marine sedimentation and preservation.

Rhinoconjunctivitis Symptoms in Children and Adolescents with Asthma: A Longitudinal Clustering Analysis.

Background: Rhinoconjunctivitis phenotypes are conventionally described based on symptom severity, duration and seasonality and aeroallergen sensitization. It is not known whether these phenotypes fully reflect the patterns of symptoms seen at a population level.

Objective: To identify phenotypes of rhinoconjunctivitis based on symptom intensity and seasonality using an unbiased approach and to compare their characteristics.