Reentrant phase transition in a predator-prey model

We numerically investigate the six-species predator-prey game in complex networks as well as in $d$-dimensional hypercubic lattices with $d=1,2,..., 6$. The interaction topology of the six species contains two loops, each of which is composed of cyclically predating three species. As the mutation rate $P$ is lowered below the well-defined phase transition point, the $Z_2$ symmetry related with the interchange of the two loops is spontaneously broken, and it has been known that the system develops the defensive alliance in which three cyclically predating species defend each other against the invasion of other species. In the small-world network structure characterized by the rewiring probability $\alpha$, the phase diagram shows the reentrant behavior as $\alpha$ is varied, indicating a twofold role of the shortcuts. In $d$-dimensional regular hypercubic lattices, the system also exhibits the reentrant phase transition as $d$ is increased. We identify universality class of the phase transition and discuss the proper mean-field limit of the system.Comment: 8 pages, 7 figures, Phys. Rev. E (in press

A Comparison of the Intrinsic Shapes of Two Different Types of Dwarf Galaxies: Blues Compact Dwarfs and Dwarf Ellipticals

We measure the apparent shapes for a sample of 62 blue compact dwarf galaxies (BCDs), and compare them with the apparent shapes for a sample of 80 dwarf elliptical galaxies (dEs). The BCDs are flatter, on average, than the dEs, but the difference is only marginally significant. We then use both non-parametric and parametric techniques to determine possible distributions of intrinsic shapes for the BCDs. The hypothesis that BCDs are oblate spheroids can be ruled out with a high confidence level ($> 99$), but the hypothesis that they are prolate spheroids cannot be excluded. The apparent shapes of BCDs are totally consistent with the hypothesis that they are triaxial ellipsoids. If the intrinsic axis ratios, $\beta$ and $\gamma$, are distributed according to a Gaussian with means $\beta_0$ and $\gamma_0$ and standard deviation $\sigma$, we find the best-fitting distribution for BCDs has $(\beta_0,\gamma_0,\sigma)= (0.66,0.55,0.16)$, while that for dEs has $(\beta_0,\gamma_0,\sigma)= (0.85,0.64,0.24)$. Our results are consistent with the hypothesis that BCDs have a close evolutionary relation with dEs.Comment: total 23 pages, 9 figures, and 1 Table, submitted to ApJ on Sep 19 1997. Email addresses: [email protected], [email protected], [email protected], [email protected], [email protected]

The Student Movement Volume 105 Issue 6: AU Infused with New Cultural Perspectives

NEWS Andrews University Wind Symphony Performs Songs of the Sea Concert, Jenae Rogers Dr. Marilyn McEntyre Speaks at John O. Walker Lecture, Taylor Uphus Students Worship Together at Infusion Vespers, Caralynn Chan PULSE Interest and Apathy Towards Politics, Wambui Karanja Memories of Chuseok: Celebrating Community, Jessica Rim Pumpkin Spice: Deconstructed, Masy Domecillo HUMANS Explaining the Letter: Talking with Kelli Coffen, Interviewed by Abigail Lee Holly Sharp, AFIA Cultural VP, on Filipino American History Month, Interviewed by Terika Williams Thoughts on the Last Presidential Debate, Interviewed by Alyssa Henriquez ARTS & ENTERTAINMENT Another Fall Playlist!, Created by Evin N. Musgrove Artist Spotlight: Courtney Saunders, Interviewed by Pearl Parker Unorthodox, Hannah Cruse IDEAS Get Your Flu Shot! Now More Than Ever, Sung Been Han Just This Once , Evin N. Musgrove LAST WORD Apoliticism in Election Season, Daniel Selfhttps://digitalcommons.andrews.edu/sm-105/1006/thumbnail.jp

Polarity-tunable magnetic tunnel junctions based on ferromagnetism at oxide heterointerfaces

Complex oxide systems have attracted considerable attention because of their fascinating properties, including the magnetic ordering at the conducting interface between two band insulators, such as LaAlO3 (LAO) and SrTiO3 (STO). However, the manipulation of the spin degree of freedom at the LAO/STO heterointerface has remained elusive. Here, we have fabricated hybrid magnetic tunnel junctions consisting of Co and LAO/STO ferromagnets with the insertion of a Ti layer in between, which clearly exhibit magnetic switching and the tunnelling magnetoresistance (TMR) effect below 10 K. The magnitude and the of the TMR are strongly dependent on the direction of the rotational magnetic field parallel to the LAO/STO plane, which is attributed to a strong Rashba-type spin orbit coupling in the LAO/STO heterostructure. Our study provides a further support for the existence of the macroscopic ferromagnetism at LAO/STO heterointerfaces and opens a novel route to realize interfacial spintronics devices.Comment: 25 pages, 5 figure

Anomalous Dynamics of Translocation

We study the dynamics of the passage of a polymer through a membrane pore (translocation), focusing on the scaling properties with the number of monomers $N$. The natural coordinate for translocation is the number of monomers on one side of the hole at a given time. Commonly used models which assume Brownian dynamics for this variable predict a mean (unforced) passage time $\tau$ that scales as $N^2$, even in the presence of an entropic barrier. However, the time it takes for a free polymer to diffuse a distance of the order of its radius by Rouse dynamics scales with an exponent larger than 2, and this should provide a lower bound to the translocation time. To resolve this discrepancy, we perform numerical simulations with Rouse dynamics for both phantom (in space dimensions $d=1$ and 2), and self-avoiding (in $d=2$) chains. The results indicate that for large $N$, translocation times scale in the same manner as diffusion times, but with a larger prefactor that depends on the size of the hole. Such scaling implies anomalous dynamics for the translocation process. In particular, the fluctuations in the monomer number at the hole are predicted to be non-diffusive at short times, while the average pulling velocity of the polymer in the presence of a chemical potential difference is predicted to depend on $N$.Comment: 9 pages, 9 figures. Submitted to Physical Review

The Student Movement Volume 105 Issue 10: One Dose Down, One to Go!: President Luxton Vaccinated

NEWS Andrews University Holds Employee Awards Virtual Celebration, Jenae Rogers New Life Hosts Black Like Me: Growing Up Black, Caralynn Chan Texas Winter Storm Impacts Families of Students at Andrews, Taylor Uphus The Red Cross Blood Drive Reveals Growing Shortage in Donor Participation, Amanda Cho PULSE Favorite Meals: Café Edition, Interviewed by Alec Bofetiado The Wellness Column: Decluttering your Room and Mind, HeeYun Oh The Wellness Column: Decluttering Your Room and Mind, Jessica Rim HUMANS AUSA Candidate Interviews, Interviewed by Abigail Lee Freshman Spotlight: Rekha Isaac, Interviewed by Celeste Richardson Trusting the Science, Interviewed by Pearl Parker ARTS & ENTERTAINMENT Creative Spotlight: Karla Torres, Interviewed by Megan Napod Current Favorites: March, Megan Napod Signal Boost: Canvas, Hannah Cruse IDEAS A Woman and Her God, Evin N. Musgrove COVID-19 Updates: The Variants, the Vaccines, and Other News, Sung Been Han Parler, QAnon, and the Freedom of Speech: What Should be Done?, Abigail Lee THE LAST WORD Taking Stock, Masy Domecillohttps://digitalcommons.andrews.edu/sm-105/1013/thumbnail.jp

Enhanced Metallic Properties of SrRuO\u3csub\u3e3\u3c/sub\u3e Thin Films via Kinetically Controlled Pulsed Laser Epitaxy

Metal electrodes are a universal element of all electronic devices. Conducting SrRuO3 (SRO) epitaxial thin films have been extensively used as electrodes in complex-oxide heterostructures due to good lattice mismatches with perovskite substrates. However, when compared to SRO single crystals, SRO thin films have shown reduced conductivity and Curie temperatures (TC), which can lead to higher Joule heating and energy loss in the devices. Here, we report that high-quality SRO thin films can be synthesized by controlling the plume dynamics and growth rate of pulsed laser epitaxy (PLE) with real-time optical spectroscopic monitoring. The SRO thin films grown under the kinetically controlled conditions, down to ca. 16 nm in thickness, exhibit both enhanced conductivity and TC as compared to bulk values, due to their improved stoichiometry and a strain-mediated increase of the bandwidth of Ru 4d electrons. This result provides a direction for enhancing the physical properties of PLE-grown thin films and paves a way to improved device applications

Enhanced Metallic Properties of SrRuO\u3csub\u3e3\u3c/sub\u3e Thin Films via Kinetically Controlled Pulsed Laser Epitaxy

Metal electrodes are a universal element of all electronic devices. Conducting SrRuO3 (SRO) epitaxial thin films have been extensively used as electrodes in complex-oxide heterostructures due to good lattice mismatches with perovskite substrates. However, when compared to SRO single crystals, SRO thin films have shown reduced conductivity and Curie temperatures (TC), which can lead to higher Joule heating and energy loss in the devices. Here, we report that high-quality SRO thin films can be synthesized by controlling the plume dynamics and growth rate of pulsed laser epitaxy (PLE) with real-time optical spectroscopic monitoring. The SRO thin films grown under the kinetically controlled conditions, down to ca. 16 nm in thickness, exhibit both enhanced conductivity and TC as compared to bulk values, due to their improved stoichiometry and a strain-mediated increase of the bandwidth of Ru 4d electrons. This result provides a direction for enhancing the physical properties of PLE-grown thin films and paves a way to improved device applications

The VVV Templates Project. Towards an Automated Classification of VVV Light-Curves. I. Building a database of stellar variability in the near-infrared

Context. The Vista Variables in the V\'ia L\'actea (VVV) ESO Public Survey is a variability survey of the Milky Way bulge and an adjacent section of the disk carried out from 2010 on ESO Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV will eventually deliver a deep near-IR atlas with photometry and positions in five passbands (ZYJHK_S) and a catalogue of 1-10 million variable point sources - mostly unknown - which require classifications. Aims. The main goal of the VVV Templates Project, that we introduce in this work, is to develop and test the machine-learning algorithms for the automated classification of the VVV light-curves. As VVV is the first massive, multi-epoch survey of stellar variability in the near-infrared, the template light-curves that are required for training the classification algorithms are not available. In the first paper of the series we describe the construction of this comprehensive database of infrared stellar variability. Methods. First we performed a systematic search in the literature and public data archives, second, we coordinated a worldwide observational campaign, and third we exploited the VVV variability database itself on (optically) well-known stars to gather high-quality infrared light-curves of several hundreds of variable stars. Results. We have now collected a significant (and still increasing) number of infrared template light-curves. This database will be used as a training-set for the machine-learning algorithms that will automatically classify the light-curves produced by VVV. The results of such an automated classification will be covered in forthcoming papers of the series.Comment: 12 pages, 16 figures, 3 tables, accepted for publication in A&A. Most of the data are now accessible through http://www.vvvtemplates.org