New Estimation Approaches for the Hierarchical Linear Ballistic Accumulator Model

The Linear Ballistic Accumulator (Brown & Heathcote, 2008) model is used as a measurement tool to answer questions about applied psychology. The analyses based on this model depend upon the model selected and its estimated parameters. Modern approaches use hierarchical Bayesian models and Markov chain Monte-Carlo (MCMC) methods to estimate the posterior distribution of the parameters. Although there are several approaches available for model selection, they are all based on the posterior samples produced via MCMC, which means that the model selection inference inherits the properties of the MCMC sampler. To improve on current approaches to LBA inference we propose two methods that are based on recent advances in particle MCMC methodology; they are qualitatively different from existing approaches as well as from each other. The first approach is particle Metropolis-within-Gibbs; the second approach is density tempered sequential Monte Carlo. Both new approaches provide very efficient sampling and can be applied to estimate the marginal likelihood, which provides Bayes factors for model selection. The first approach is usually faster. The second approach provides a direct estimate of the marginal likelihood, uses the first approach in its Markov move step and is very efficient to parallelize on high performance computers. The new methods are illustrated by applying them to simulated and real data, and through pseudo code. The code implementing the methods is freely available.Comment: 35 pages, 6 figures, 7 table

Communication intercellulaire et infections microbiennes / Intercellular communication and microbial infections

Recherche Au cours des deux dernières décennies, il est devenu évident que, comme décrit pour les cellules eucaryotes, la sous-localisation des protéines dans les bactéries joue un rôle clé dans leur fonction ou leur régulation spatiotemporelle [1, 2]. Cependant, contrairement aux cellules eucaryotes, les bactéries ne contiennent pas de membranes intracellulaires délimitant les compartiments internes. Ainsi, la localisation des protéines bactériennes repose sur d’autres mécanismes encore mal ..

Shigella applies molecular mimicry to subvert vinculin and invade host cells

Shigella flexneri, the causative agent of bacillary dysentery, injects invasin proteins through a type III secretion apparatus upon contacting the host cell, which triggers pathogen internalization. The invasin IpaA is essential for S. flexneri pathogenesis and binds to the cytoskeletal protein vinculin to facilitate host cell entry. We report that IpaA harbors two vinculin-binding sites (VBSs) within its C-terminal domain that bind to and activate vinculin in a mutually exclusive fashion. Only the highest affinity C-terminal IpaA VBS is necessary for efficient entry and cell–cell spread of S. flexneri, whereas the lower affinity VBS appears to contribute to vinculin recruitment at entry foci of the pathogen. Finally, the crystal structures of vinculin in complex with the VBSs of IpaA reveal the mechanism by which IpaA subverts vinculin's functions, where S. flexneri utilizes a remarkable level of molecular mimicry of the talin–vinculin interaction to activate vinculin. Mimicry of vinculin's interactions may therefore be a general mechanism applied by pathogens to infect the host cell

ARCHON to ASpace: Adventures in Archives Migration

In August 2018, the University Archives and Southern Minnesota Historical Center at Minnesota State University, Mankato decided to migrate our finding aids and collection information from a hidden ARCHON database to a publicly available ArchivesSpace instance. This time sensitive decision was made with no budget available and in the midst of both a library system migration (Aleph to Alma/Primo) and an entire University website migration that affected us more than we initially thought. Three migrations is no big deal, right? This session will talk about our migration from design to implementation to “Oops! Where did that go?” We will share with you what worked and what didn’t in our path to creating a new searchable archives tool for our patrons