HyperVAE: A Minimum Description Length Variational Hyper-Encoding Network

We propose a framework called HyperVAE for encoding distributions of distributions. When a target distribution is modeled by a VAE, its neural network parameters \theta is drawn from a distribution p(\theta) which is modeled by a hyper-level VAE. We propose a variational inference using Gaussian mixture models to implicitly encode the parameters \theta into a low dimensional Gaussian distribution. Given a target distribution, we predict the posterior distribution of the latent code, then use a matrix-network decoder to generate a posterior distribution q(\theta). HyperVAE can encode the parameters \theta in full in contrast to common hyper-networks practices, which generate only the scale and bias vectors as target-network parameters. Thus HyperVAE preserves much more information about the model for each task in the latent space. We discuss HyperVAE using the minimum description length (MDL) principle and show that it helps HyperVAE to generalize. We evaluate HyperVAE in density estimation tasks, outlier detection and discovery of novel design classes, demonstrating its efficacy

Machine learning reveals orbital interaction in crystalline materials

We propose a novel representation of crystalline materials named orbital-field matrix (OFM) based on the distribution of valence shell electrons. We demonstrate that this new representation can be highly useful in mining material data. Our experiment shows that the formation energies of crystalline materials, the atomization energies of molecular materials, and the local magnetic moments of the constituent atoms in transition metal--rare-earth metal bimetal alloys can be predicted with high accuracy using the OFM. Knowledge regarding the role of coordination numbers of transition-metal and rare-earth metal elements in determining the local magnetic moment of transition metal sites can be acquired directly from decision tree regression analyses using the OFM.Comment: 10 page

Bond switching from two- to three-dimensional polymers of C60 at high pressure

In situ high pressure x-ray diffraction experiments revealed that a transformation from the two-dimensional (2D) tetragonal C60 polymer to a three-dimensional (3D) polymer takes place via a highly anisotropic deformation of C60 molecules along the c axis, as an irreversible first-order transformation above 20 GPa. In the 3D polymer phase, the 2+2 bonds remain in the 2D plane, while neighboring layers are connected by the 3+3 bonds. The bulk modulus of the 3D polymer was 407 GPa, being slightly smaller than that of diamond

Alternative splicing produces structural and functional changes in CUGBP2

<p>Abstract</p> <p>Background</p> <p>CELF/Bruno-like proteins play multiple roles, including the regulation of alternative splicing and translation. These RNA-binding proteins contain two RNA recognition motif (RRM) domains at the N-terminus and another RRM at the C-terminus. CUGBP2 is a member of this family of proteins that possesses several alternatively spliced exons.</p> <p>Results</p> <p>The present study investigated the expression of exon 14, which is an alternatively spliced exon and encodes the first half of the third RRM of CUGBP2. The ratio of exon 14 skipping product (<it>R3δ</it>) to its inclusion was reduced in neuronal cells induced from P19 cells and in the brain. Although full length CUGBP2 and the CUGBP2 <it>R3δ </it>isoforms showed a similar effect on the inclusion of the smooth muscle (SM) exon of the <it>ACTN1 </it>gene, these isoforms showed an opposite effect on the skipping of exon 11 in the <it>insulin receptor </it>gene. In addition, examination of structural changes in these isoforms by molecular dynamics simulation and NMR spectrometry suggested that the third RRM of R3δ isoform was flexible and did not form an RRM structure.</p> <p>Conclusion</p> <p>Our results suggest that CUGBP2 regulates the splicing of <it>ACTN1 </it>and <it>insulin receptor </it>by different mechanisms. Alternative splicing of <it>CUGBP2 </it>exon 14 contributes to the regulation of the splicing of the <it>insulin receptor</it>. The present findings specifically show how alternative splicing events that result in three-dimensional structural changes in CUGBP2 can lead to changes in its biological activity.</p