Rods are less fragile than spheres: Structural relaxation in dense liquids composed of anisotropic particles

We perform extensive molecular dynamics simulations of dense liquids composed of bidisperse dimer- and ellipse-shaped particles in 2D that interact via repulsive contact forces. We measure the structural relaxation times obtained from the long-time decay of the self-part of the intermediate scattering function for the translational and rotational degrees of freedom (DOF) as a function of packing fraction \phi, temperature T, and aspect ratio \alpha. We are able to collapse the \phi and T-dependent structural relaxation times for disks, and dimers and ellipses over a wide range of \alpha, onto a universal scaling function {\cal F}_{\pm}(|\phi-\phi_0|,T,\alpha), which is similar to that employed in previous studies of dense liquids composed of purely repulsive spherical particles in 3D. {\cal F_{\pm}} for both the translational and rotational DOF are characterized by the \alpha-dependent scaling exponents \mu and \delta and packing fraction \phi_0(\alpha) that signals the crossover in the scaling form {\cal F}_{\pm} from hard-particle dynamics to super-Arrhenius behavior for each aspect ratio. We find that the fragility at \phi_0, m(\phi_0), decreases monotonically with increasing aspect ratio for both ellipses and dimers. Moreover, the results for the slow dynamics of dense liquids composed of dimer- and ellipse-shaped particles are qualitatively the same, despite the fact that zero-temperature static packings of dimers are isostatic, while static packings of ellipses are hypostatic.Comment: 10 pages, 17 figures, and 1 tabl

Hypernetwork Knowledge Graph Embeddings

Knowledge graphs are graphical representations of large databases of facts, which typically suffer from incompleteness. Inferring missing relations (links) between entities (nodes) is the task of link prediction. A recent state-of-the-art approach to link prediction, ConvE, implements a convolutional neural network to extract features from concatenated subject and relation vectors. Whilst results are impressive, the method is unintuitive and poorly understood. We propose a hypernetwork architecture that generates simplified relation-specific convolutional filters that (i) outperforms ConvE and all previous approaches across standard datasets; and (ii) can be framed as tensor factorization and thus set within a well established family of factorization models for link prediction. We thus demonstrate that convolution simply offers a convenient computational means of introducing sparsity and parameter tying to find an effective trade-off between non-linear expressiveness and the number of parameters to learn

Geologic Setting and Activity of Faults in the San Fernando Area, California

The faulting associated with the San Fernando earthquake of February 9, 1971, occurred in the Transverse Ranges structural province, a region noted for its strong and relatively young tectonic deformation. This is, however, the first example of historic surface faulting within the interior of that province

The 21-SPONGE HI Absorption Survey I: Techniques and Initial Results

We present methods and results from "21-cm Spectral Line Observations of Neutral Gas with the EVLA" (21-SPONGE), a large survey for Galactic neutral hydrogen (HI) absorption with the Karl G. Jansky Very Large Array (VLA). With the upgraded capabilities of the VLA, we reach median root-mean-square (RMS) noise in optical depth of $\sigma_{\tau}=9\times 10^{-4}$ per $0.42\rm\,km\,s^{-1}$ channel for the 31 sources presented here. Upon completion, 21-SPONGE will be the largest HI absorption survey with this high sensitivity. We discuss the observations and data reduction strategies, as well as line fitting techniques. We prove that the VLA bandpass is stable enough to detect broad, shallow lines associated with warm HI, and show that bandpass observations can be combined in time to reduce spectral noise. In combination with matching HI emission profiles from the Arecibo Observatory ($\sim3.5'$ angular resolution), we estimate excitation (or spin) temperatures ($\rm T_s$) and column densities for Gaussian components fitted to sightlines along which we detect HI absorption (30/31). We measure temperatures up to $\rm T_s\sim1500\rm\,K$ for individual lines, showing that we can probe the thermally unstable interstellar medium (ISM) directly. However, we detect fewer of these thermally unstable components than expected from previous observational studies. We probe a wide range in column density between $\sim10^{16}$ and $>10^{21}\rm\,cm^{-2}$ for individual HI clouds. In addition, we reproduce the trend between cold gas fraction and average $\rm T_s$ found by synthetic observations of a hydrodynamic ISM simulation by Kim et al. (2014). Finally, we investigate methods for estimating HI $\rm T_s$ and discuss their biases.Comment: Accepted for publication in ApJ; 24 pages, 14 figure

Jamming in Systems Composed of Frictionless Ellipse-Shaped Particles

We study the structural and mechanical properties of jammed ellipse packings, and find that the nature of the jamming transition in these systems is fundamentally different from that for spherical particles. Ellipse packings are generically hypostatic with more degrees of freedom than constraints. The spectra of low energy excitations possess two gaps and three distinct branches over a range of aspect ratios. In the zero compression limit, the energy of the modes in the lowest branch increases {\it quartically} with deformation amplitude, and the density of states possesses a $\delta$-function at zero frequency. We identify scaling relations that collapse the low-frequency part of the spectra for different aspect ratios. Finally, we find that the degree of hypostaticity is determined by the number of quartic modes of the packing.Comment: 4 pages, 4 figure

Proceedings of the 45th Annual Meeting of the Southern Soybean Disease Workers (March 7-8, 2018, Pensacola Beach, Florida)

Contents List of SSDW Officers Agenda for March 7-8, 2018 Abstracts for contributed/presented papers Retrospective analyses regarding the impact of soybean diseases in the USA .TW Allen, PD Esker, and CA Bradley Diaporthe (Phomopsis) species on soybean: current status in the United States. Febina Mathew, Kristina Petrovic, Lisa Castlebury, Tom Allen, Gary Bergstrom, John Bonkowski, Carl Bradley, James Buck, Emmanuel Byamukama, Martin Chilvers, Anne Dorrance, Nicholas Dufault, Loren Giesler, Nancy Gregory, Heather Kelly, Nathan Kleczewski, Trey Price, Dean Malvick, Sam Markell, Daren Mueller, Damon Smith, Terry Spurlock, Kiersten Wise, and Marina Johnson New insights into the genetic underpinnings of pathogenesis in Cercospora cf. flagellaris. Burt Bluhm, Ahmad Fakhoury, Alex Zaccaron, and Kona Swift Evaluation of spore traps and molecular tools for a fungicide decision model for frogeye leaf spot. HM Kelly and B Lin Site-specific management strategies against multiple nematode species in soybean. C Overstreet, EC McGawley, DM Xavier-Mis, and JS Rezende Field efficacy of two new seed-applied biological agents for suppression of root-knot nematodes in soybean. Travis R Faske, Michael Emerson, and Katherine Hurd Evaluation of 418 soybean plant introductions with reported resistance to soybean cyst nematode for reniform nematode resistance. Robert T Robbins and Devany Crippen Studies on Soybean vein necrosis virus in Alabama. EJ Sikora, D Delaney, A Jacobson, K Conner, A Chitturi, and J Kemble Using unmanned aerial vehicle (UAV) photograph analysis to generate corroborating data in small plot soybean fungicide efficacy trials. P Price, MA Purvis, and P Washam Building a foundation for cultivar and fungicide selection decisions in soybean. HM Kelly Results from the 2017 Mississippi State University target spot fungicide efficacy program. TW Allen and TH Wilkerson Relating temperature and relative humidity in commercial warehouses to decline in vigor of soybean seed stored for late plantings in Arkansas. JC Rupe, JA Lee, A Palmer, RT Holland, J Robinson, RD Cartwright, and G Atungulu Seed treatment for sudden death syndrome management in soybean. Yuba R Kandel, Carl A Bradley, Martin I Chilvers, Febina M Mathew, Albert U Tenuta, Damon L Smith, Kiersten A Wise, and Daren S Mueller Evaluation of screening methods for soil-borne diseases of soybean (Glycine max) in west Tennessee. R Guyer, E Zuchelli, and H Kelly Abstracts for student papers An update on taproot decline in Arkansas. J Bailey, AC Tolbert, B Boney, and TN Spurlock Taproot decline of soybean is caused by an undescribed species in the Genus Xylaria. T Garcia-Aroca, P Price, M Tomaso-Peterson, T Spurlock, TR Faske, B Bluhm, K Conner, EJ Sikora, R Guyer, H Kelly, TW Allen, and VP Doyle Assessing pathogenicity and virulence of Xylaria sp. isolates from Mississippi soybean. H Renfroe, T Wilkerson, T Allen, and M Tomaso-Peterson Effects of mycovirus infection on virulence of Rhizoctonia solani in soybean. TJ Stetina, CS Rothrock, and TN Spurlock Is the emergence of Soybean vein necrosis virus linked to the re-emergence of Tobacco streak virus? C Zambrana-Echevarría, CL Groves, TL German, and DL Smith Is soybean vein necrosis a threat to soybean production? NR Anderson, MD Irizarry, CA Bloomingdale, DL Smith, CA Bradley, DP Delaney, NM Kleczewski, EJ Sikora, DS Mueller, and KA Wise Yield prediction in soybean fields using satellite imagery. B Boney and TN Spurlock Elucidating the race population structure of Cercospora sojina through genotypic patterns. Wagner Fagundes, Marcio Zaccaron, Alex Zaccaron, and Burton H Bluhm Impact of foliar fungicide applications in soybean fields across aggregated distributions of disease. M Patterson, AC Tolbert, and TN Spurlock Abstract for presented poster Assessing the genetic diversity of Cercospora spp. associated with Cercospora leaf blight of soybean in North America. Kona Swift and Burt Bluhm Southern United States soybean disease loss estimates for 2017. TW Allen, K Bissonnette, CA Bradley, JP Damicone, NS Dufault, TR Faske, CA Hollier, T Isakeit, RC Kemerait, NM Kleczewski, HL Mehl, JD Mueller, C Overstreet, PP Price, EJ Sikora, TN Spurlock, L Thiessen, and H Young Proceedings of the Southern Soybean Disease Workers area published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by authors. The opinions expressed by the participants at this conference are their own and do not necessarily represent those of the Southern Soybean Disease Workers. Mention of a trademark or proprietary products in this publication does not constitute a guarantee, warranty, or endorsement of that product by the Southern Soybean Disease Workers. Appreciation is given to the staff at the University of Kentucky Research & Education Center, Princeton, KY, for their assistance in assembling these Proceedings

Path integral Monte Carlo simulations for rigid rotors and their application to water

In this work the path integral formulation for rigid rotors, proposed by M\"user and Berne [Phys. Rev. Lett. {\bf 77}, 2638 (1996)], is described in detail. It is shown how this formulation can be used to perform Monte Carlo simulations of water. Our numerical results show that whereas some properties of water can be accurately reproduced using classical simulations with an empirical potential which, implicitly, includes quantum effects, other properties can only be described quantitatively when quantum effects are explicitly incorporated. In particular, quantum effects are extremely relevant when it comes to describing the equation of state of the ice phases at low temperatures, the structure of the ices at low temperatures, and the heat capacity of both liquid water and the ice phases. They also play a minor role in the relative stability of the ice phases.Comment: to appear in Molecular Physics (2011

Geologic Setting and Activity of Faults in the San Fernando Area, California

The faulting associated with the San Fernando earthquake of February 9, 1971, occurred in the Transverse Ranges structural province, a region noted for its strong and relatively young tectonic deformation. This is, however, the first example of historic surface faulting within the interior of that province