Current flux imaging of a micromagnetic electrofoil

Like air flowing over a wing, optimizing the flow of electronic charge is essential to the operation of nanoscale devices. Unfortunately, the delicate interplay of charge, spin, and heat in complex devices has precluded detailed imaging of charge flow. Here, we report on the visualization of intrinsic charge current streamlines through yttrium iron garnet micromagnetic heterostructures. Scanning photovoltage microscopy of precisely designed devices leads to striking spatial patterns, with prominent photovoltage features emerging in corners and narrow constrictions. These patterns, which evolve continuously with rotation of an external magnetic field, enable rich spatial mapping of fluid-like flow. Taking inspiration from aerodynamic Clark Y airfoils, we engineer micromagnetic wing shaped devices, called electrofoils, which allow us to precisely contort, compress and decompress flowlines of electronic charge.Comment: 7 Pages, 4 figures, supplemental materials attached after reference

Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K–Pg boundary

It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous–Palaeogene (K– Pg) extinction event.We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10-20 Myr prior to the K–Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K–Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K–Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.</p

Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K–Pg boundary

It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous–Palaeogene (K– Pg) extinction event.We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10-20 Myr prior to the K–Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K–Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K–Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.</p

Data from: Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K-Pg boundary

It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous&ndash;Palaeogene (K&ndash;Pg) extinction event. We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10&ndash;20 Myr prior to the K&ndash;Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K&ndash;Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K&ndash;Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.,Fossil occurrence datasetFossil occurrences of tribosphenidan mammals from the Cretaceous through Selandian. This dataset is modified from an occurrence list downloaded from the Paleobiology Database (www.paleobiodb.org) on November 19, 2015.Grossnickle&amp;amp;Newham2016_FossilOccurrenceDataset.xlsxMolar landmark and outline coordinatesThese are the original point coordinates (in tps format) used in a geometric morphometric analysis of lower molar shape. For each genus, the first seven coordinates are cusp landmarks, the next 20 coordinates outline the talonid, and the final 20 coordinates outline the trigonid. (Note that the outline coordinates are not equally-spaced semilandmarks.) See Grossnickle &amp;amp; Newham (2016) for information concerning how these coordinates were analyzed.molar_LM_coords_GrossnickleNewham2016.xlsx,</span

Molar landmark and outline coordinates

These are the original point coordinates (in tps format) used in a geometric morphometric analysis of lower molar shape. For each genus, the first seven coordinates are cusp landmarks, the next 20 coordinates outline the talonid, and the final 20 coordinates outline the trigonid. (Note that the outline coordinates are not equally-spaced semilandmarks.) See Grossnickle & Newham (2016) for information concerning how these coordinates were analyzed

Fossil occurrence dataset

Fossil occurrences of tribosphenidan mammals from the Cretaceous through Selandian. This dataset is modified from an occurrence list downloaded from the Paleobiology Database (www.paleobiodb.org) on November 19, 2015

The functional diversity of marsupial limbs is influenced by both ecology and developmental constraint

Extant marsupials are less ecologically diverse than placentals, and this is reflected by placentals exhibiting a greater diversity of locomotor modes, including powered flight and fully aquatic swimming. One proposed explanation for this discrepancy is that the development of more disparate marsupial forelimbs is prevented by the neonate’s crawl to the pouch, which requires precocious forelimb development for climbing adaptations. To test predictions of this Developmental Constraint Hypothesis (DCH), we pursue a comparative morphometric study on osteological traits of mammalian limbs, with an emphasis on functional differentiation of marsupial limbs among locomotor modes. We apply multivariate analyses to a large dataset of limb metrics and a diverse sample of mammals, with the placental sample limited to taxa whose locomotor modes are exhibited in marsupials. Overall, we do not find consistent evidence in support of the DCH. Diprotodontia serves as an exception, with comparisons of their forelimbs to hind limbs supporting the DCH. Our results suggest that developmental constraints on marsupial forelimbs may have limited marsupial diversity to some degree. Despite this, the marsupial locomotor groups show unexpectedly high levels of morphological differentiation relative to placentals of the same locomotor modes, indicating that ecological functions may overcome developmental constraints on a macroevolutionary scale

Gliding toward an understanding of the origin of flight in bats

Bats are the only mammals capable of powered flight and have correspondingly specialized body plans, particularly in their limb morphology. The origin of bat flight is still not fully understood due to an uninformative fossil record but, from the perspective of a functional transition, it is widely hypothesized that bats evolved from gliding ancestors. Here, we test predictions of the gliding-to-flying hypothesis of the origin of bat flight by using phylogenetic comparative methods to model the evolution of forelimb and hindlimb traits on a dataset spanning four extinct bats and 231 extant mammals with diverse locomotor modes. Our results reveal that gliders exhibit adaptive trait optima (1) toward relatively elongate forelimbs that are intermediate between those of bats and non-gliding arborealists, and (2) toward relatively narrower but not longer hindlimbs that are intermediate between those of non-gliders and bats. We propose an adaptive landscape based on limb length and width optimal trends derived from our modeling analyses. Our results support a hypothetical evolutionary pathway wherein glider-like postcranial morphology precedes a bat-like morphology adapted to powered-flight, setting a foundation for future developmental, biomechanical, and evolutionary research to test this idea

Transfer from Spatial Education to Verbal Reasoning and Prediction of Transfer from Classroom-Based Neural Change

Assessing whether learning in one domain is transferable to abilities in other domains often eludes traditional testing. Thus, a question with bearing on the promise of neuroscience for education is whether neural changes that accompany in-school curriculum learning can improve prediction of learning transfer. Separately, debate in philosophy and psychology has long concerned whether spatial processes underlie seemingly nonspatial/verbal human reasoning (e.g., mental model theory; MMT). If so, education that fosters spatial cognition might yield transfer to improved verbal reasoning. Here, in real-world classrooms studied in a quasi-experimental design, a STEM curriculum devised to foster spatial cognition yielded improved spatial abilities and-consistent with MMT-transferred beyond the spatial domain to improved verbal reasoning. Further supporting MMT, the more students’ spatial ability improved, the more their verbal reasoning improved, and spatial ability improvement mediated curriculum transfer. At the neural level, longitudinal fMRI detected curriculum-driven changes in activity, connectivity, and representational similarity of brain regions implicated in spatial cognition. Critically, changes in spatial cognition-linked neural activity robustly predicted curriculum transfer-more accurately than testing and grades-and mediated this transfer. Reports by the National Research Council and others note that spatial abilities reliably predict STEM achievement, but that broad adoption of spatial cognition-focused curricula depends on classroom-based evidence of efficacy and mechanisms-of-change. The present findings support the real-world application of MMT to classrooms via “spatial education.” Further, demonstrating that in-school neural change can predict transfer over-and-above performance-based assessment suggests the long-term achievability of neurally-informed curriculum development that leverages neural change to identify and design transferable curricula