Fire in the tree: The origin and distribution of fire-adapted traits within conifers and their influence on speciation rates across the conifer phylogeny.

Premise: Considering rapidly changing fire regimes due to anthropogenic disturbances to climate and fuel loads, it is crucial to understand the underpinnings driving fire-adapted trait evolution. Among the oldest lineages affected by fire is Coniferae. This lineage occupies a variety of fire prone and non-fire prone habitats across all hemispheres and has four fire-adapted traits: (1) thick bark; (2) serotiny; (3) seedling grass stage; and (4) resprouting ability.

Fast imaging of millimeter-scale areas with beam deflection transmission electron microscopy.

Serial section transmission electron microscopy (TEM) has proven to be one of the leading methods for millimeter-scale 3D imaging of brain tissues at nanoscale resolution. It is important to further improve imaging efficiency to acquire larger and more brain volumes. We report here a threefold increase in the speed of TEM by using a beam deflecting mechanism to enable highly efficient acquisition of multiple image tiles (nine) for each motion of the mechanical stage.

Magnetic voluntary head-fixation in transgenic rats enables lifespan imaging of hippocampal neurons.

The precise neural mechanisms within the brain that contribute to the remarkable lifetime persistence of memory are not fully understood. Two-photon calcium imaging allows the activity of individual cells to be followed across long periods, but conventional approaches require head-fixation, which limits the type of behavior that can be studied. We present a magnetic voluntary head-fixation system that provides stable optical access to the brain during complex behavior.

Neural circuit models for evidence accumulation through choice-selective sequences.

Decision making is traditionally thought to be mediated by populations of neurons whose firing rates persistently accumulate evidence across time. However, recent decision-making experiments in rodents have observed neurons across the brain that fire sequentially as a function of spatial position or time, rather than persistently, with the subset of neurons in the sequence depending on the animal's choice. We develop two new candidate circuit models, in which evidence is encoded either in the relative firing rates of two competing chains of neurons or in the network location of a stereotyped pattern ("bump") of neural activity.

Calceolariaceae809: A bait set for targeted sequencing of nuclear loci.

Premise: The genus (Calceolariaceae) is emblematic of the Andes, is hypothesized to have originated as a recent, rapid radiation, and has important taxonomic needs. Additionally, the genus is a model for the study of specialized pollination systems, as its flowers are nectarless and many offer floral oils as a pollination reward collected by specialist bees. Despite their evolutionary and ecological significance, obtaining a resolved phylogeny for the group has proved difficult.