Mechanistic insights into hydration-driven shape memory response in keratinous avian feather structures.

Keratinous materials found in the feather shafts of flying birds possess impressive mechanical attributes, combining excellent strength-to-weight balance, toughness, and more. In this study, we investigate the shape memory effect in bird feather shafts, examining its underlying design principles as templates for bioinspired shape memory composites. Through analytical and computational analysis, we aim to uncover the underlying rules and design guidelines based on stimulus-induced softening (pertaining to strength and/or stiffness) and swelling (pertaining to expansion in volume).

Kinship clustering within an ecologically diverse killer whale metapopulation.

Metapopulation dynamics can be shaped by foraging ecology, and thus be sensitive to shifts in prey availability. Genotyping 204 North Atlantic killer whales at 1346 loci, we investigated whether spatio-temporal population structuring is linked to prey type and distribution. Using population-based methods (reflecting evolutionary means), we report a widespread metapopulation connected across ecological groups based upon nuclear genome SNPs, yet spatial structuring based upon mitogenome haplotypes.

Evidence That Growth Mixture Model Results Are Highly Sensitive to Scoring Decisions.

Interest in identifying latent growth profiles to support the psychological and social-emotional development of individuals has translated into the widespread use of growth mixture models (GMMs). In most cases, GMMs are based on scores from item responses collected using survey scales or other measures. Research already shows that GMMs can be sensitive to departures from ideal modeling conditions and that growth model results outside of GMMs are sensitive to decisions about how item responses are scored, but the impact of scoring decisions on GMMs has never been investigated.

A case of renovascular hypertension due to polyarteritis nodosa.

In renal vasculitis, luminal narrowing can reduce blood flow and activate the renin-angiotensin-aldosterone system, causing renovascular hypertension. We present the case of a 47-year-old man with previous intestinal tuberculosis and episodes of lumbar pain, tender erythematous nodules and arthralgias. He had grade 3 hypertension, unresponsive to treatment, with left ventricular concentric hypertrophy and chronic kidney disease.