Exact BPS bound for noncommutative baby Skyrmions
Energy Technology Data Exchange (ETDEWEB)
Domrin, Andrei, E-mail: domrin@mi.ras.ru [Department of Mathematics and Mechanics, Moscow State University, Leninskie gory, 119992, GSP-2, Moscow (Russian Federation); Lechtenfeld, Olaf, E-mail: lechtenf@itp.uni-hannover.de [Institut für Theoretische Physik and Riemann Center for Geometry and Physics, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover (Germany); Linares, Román, E-mail: lirr@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, C.P. 09340, México D.F. (Mexico); Maceda, Marco, E-mail: mmac@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, C.P. 09340, México D.F. (Mexico)
2013-11-25
The noncommutative baby Skyrme model is a Moyal deformation of the two-dimensional sigma model plus a Skyrme term, with a group-valued or Grassmannian target. Exact abelian solitonic solutions have been identified analytically in this model, with a singular commutative limit. Inside any given Grassmannian, we establish a BPS bound for the energy functional, which is saturated by these baby Skyrmions. This asserts their stability for unit charge, as we also test in second-order perturbation theory.
International Nuclear Information System (INIS)
Blaizot, J.P.
1985-03-01
This review is an introduction to the physics of the Skyrmion. The Skyrme model is described with emphasis on its most important qualitative aspects. The interpretation of Skyrme model as an effective theory related to QCD is discussed. The semi-classical quantization of the Skyrmion is presented and justification is given for the interpretation of the winding number as the baryon number. It is show that chiral Lagrangian may provide a unifying framework for baryon and meson phenomenologies
Gauged BPS baby Skyrmions with quantized magnetic flux
Adam, C.; Wereszczynski, A.
2017-06-01
A new type of gauged BPS baby Skyrme model is presented, where the derivative term is just the Schroers current (i.e., gauge invariant and conserved version of the topological current) squared. This class of models has a topological bound saturated for solutions of the pertinent Bogomolnyi equations supplemented by a so-called superpotential equation. In contrast to the gauged BPS baby Skyrme models considered previously, the superpotential equation is linear and, hence, completely solvable. Furthermore, the magnetic flux is quantized in units of 2 π , which allows, in principle, to define this theory on a compact manifold without boundary, unlike all gauged baby Skyrme models considered so far.
Tretiakov, Oleg; Barker, Joseph
Skyrmions are topologically protected entities in magnetic materials which have the potential to be used in spintronics for information storage and processing. However, skyrmions in ferromagnets have some intrinsic difficulties which must be overcome to use them for spintronic applications, such as the inability to move straight along current. We show that skyrmions can also be stabilized and manipulated in antiferromagnetic materials. An antiferromagnetic skyrmion is a compound topological object with a similar but of opposite sign spin texture on each sublattice, which e.g. results in a complete cancelation of the Magnus force. We find that the composite nature of antiferromagnetic skyrmions gives rise to different dynamical behavior, both due to an applied current and temperature effects. O.A.T. and J.B. acknowledge support by the Grants-in-Aid for Scientific Research (Nos. 25800184, 25247056, 25220910 and 15H01009) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan and SpinNet.
International Nuclear Information System (INIS)
Battye, Richard A.; Houghton, Conor J.; Sutcliffe, Paul M.
2003-01-01
In this article we aim to determine the baryon numbers at which the minimal energy Skyrmion has icosahedral symmetry. By comparing polyhedra which arise as minimal energy Skyrmions with the dual of polyhedra that minimize the energy of Coulomb charges on a sphere, we are led to conjecture a sequence of magic baryon numbers, B=7,17,37,67,97,..., at which the minimal energy Skyrmion has icosahedral symmetry and unusually low energy. We present evidence for this conjecture by applying a simulated annealing algorithm to compute energy minimizing rational maps for all degrees up to 40. Further evidence is provided by the explicit construction of icosahedrally symmetric rational maps of degrees 37, 47, 67 and 97. To calculate these maps we introduce two new methods for computing rational maps with Platonic symmetries
International Nuclear Information System (INIS)
Li Tiezhong
1990-12-01
Two models of Skyrmions are suggested. In one of them the vector mesons Z μ 0 and W μ ± may stabilize the Skyrmion formed by Higgs bosons. In the other, the Skyrmion is composed of three preons via the interaction with the Higgs bosons
Skyrmions in magnetic materials
Seki, Shinichiro
2016-01-01
This brief reviews current research on magnetic skyrmions, with emphasis on formation mechanisms, observation techniques, and materials design strategies. The response of skyrmions, both static and dynamical, to various electromagnetic fields is also covered in detail. Recent progress in magnetic imaging techniques has enabled the observation of skyrmions in real space, as well as the analysis of their ordering manner and the details of their internal structure. In metallic systems, conduction electrons moving through the skyrmion spin texture gain a nontrivial quantum Berry phase, which provides topological force to the underlying spin texture and enables the current-induced manipulation of magnetic skyrmions. On the other hand, skyrmions in an insulator can induce electric polarization through relativistic spin-orbit interaction, paving the way for the control of skyrmions by an external electric field without loss of Joule heating. Because of its nanometric scale, particle nature, and electric controllabil...
Han, Jung Hoon
2017-01-01
This book summarizes some of the most exciting theoretical developments in the topological phenomena of skyrmions in noncentrosymmetric magnetic systems over recent decades. After presenting pedagogical backgrounds to the Berry phase and homotopy theory, the author systematically discusses skyrmions in the order of their development, from the Ginzburg-Landau theory, CP1 theory, Landau-Lifshitz-Gilbert theory, and Monte Carlo numerical approaches. Modern topics, such as the skyrmion-electron interaction, skyrmion-magnon interaction, and various generation mechanisms of the skyrmion are examined with a focus on their general theoretical aspects. The book concludes with a chapter on the skyrmion phenomena in the cold atom context. The topics are presented at a level accessible to beginning graduate students without a substantial background in field theory. The book can also be used as a text for those who wish to engage in the physics of skyrmions in magnetic systems, or as an introduction to the various theoret...
Neutron study of in-plane skyrmions in MnSi thin films
Meynell, S. A.; Wilson, M. N.; Krycka, K. L.; Kirby, B. J.; Fritzsche, H.; Monchesky, T. L.
2017-08-01
The magnetic structure of the in-plane skyrmions in epitaxial MnSi/Si(111) thin films is probed in three dimensions by the combination of polarized neutron reflectometry (PNR) and small-angle neutron scattering (SANS). We demonstrate that skyrmions exist in a region of the phase diagram above a temperature of 10 K. PNR shows the skyrmions are confined to the middle of the film due to the potential well formed by the surface twists. However, SANS shows that there is considerable disorder within the plane indicating that the magnetic structure is a two-dimensional skyrmion glass.
Kim, Bom Soo
2017-01-01
We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physica...
Nuclear Spectra from Skyrmions
International Nuclear Information System (INIS)
Manton, N.
2009-01-01
For some time now, the Skyrme model has been studied as an effective nonlinear field theory in nuclear physics. Its classical, stable soliton solutions, called Skyrmions, have a conserved topological charge which is identified with baryon number. A quantized Skyrmion models a nucleus. Skyrmions with baryon number a multiple of four are structurally similar to the cluster structures well-known in the a-particle model. The most convenient quantization scheme treats a Skyrmion as a rigid body in space and isospin space, and quantizes just the collective rotational motion. Some selected vibrational modes of Skyrmions may be included too. This approach has been applied previously to Skyrmions up to baryon number about 6, by Braaten and Carson, Kopeliovich, Walhout, and others. Recently, Battye, Manton, Sutcliffe and Wood have calculated the moment of inertia tensors in space and isospace for Skyrmions up to baryon number 12. The allowed spin and isospin states have been found, and the energy spectra calculated. These spectra agree quite well with experimental spectra of several light nuclei, including 6 L i, 8 B e, 1 2C , and their various isotopes. However, for this to work, the length scale needs to be set rather larger than the traditional value determined by Adkins and Nappi using the nucleon and delta resonance masses. The most interesting theoretical feature of these calculations is that isospin and spin excitations are treated in a uniform way. There are quite subtle constraints on the possible spin and isospin values, because of the classical symmetries of each Skyrmion. Manton and his students, and Battye and Sutcliffe, have published a number of papers on classical and quantized Skyrmions in journals and on the arXiv. They are also jointly contributing an invited chapter on Skyrmions and Nuclei to the book The Multifaceted Skyrmion, currently being edited by G. Brown and M. Rho.(author)
Platonic gravitating skyrmions
International Nuclear Information System (INIS)
Ioannidou, Theodora; Kleihaus, Burkhard; Kunz, Jutta
2006-01-01
We construct globally regular gravitating skyrmions, which possess only discrete symmetries. In particular, we present tetrahedral and cubic skyrmions. The SU(2) Skyrme field is parametrized by an improved harmonic map ansatz. Consistency then requires also a restricted ansatz for the metric. The numerical solutions obtained within this approximation are compared to those obtained in dilaton gravity
Rho, Mannque
2010-01-01
This is a sequel to the World Scientific volume edited by Gerald E Brown in 1994 entitled ""Selected Papers"", with Commentary, of 'Tony Hilton Royle Skyrme'. There has been a series of impressive developments in the application of the skyrmion structure to wide-ranging physical phenomena. The first volume was mainly focused on the rediscovery of the skyrmion in 1983 in the context of Quantum Chromodynamics (QCD) and on its striking role in nuclear physics. Since 1994, skyrmions have been found to play an even greater role not only in various aspects of particle physics and astrophysics but al
International Nuclear Information System (INIS)
Rho, M.
1987-02-01
The author summarizes the works presented at the meeting on skyrmions and anomalies. He divides the principal issues of this workshop into five categories: QCD effective lagrangians, chiral bags and the Cheshire cat principle, strangeness problem, phenomenology, mathematical structure
International Nuclear Information System (INIS)
Dick, Rainer
2017-01-01
A dark sector with a solitonic component provides a means to circumvent the problem of generically low annihilation cross sections of very heavy dark matter particles. At the same time, enhanced annihilation cross sections are necessary for indirect detection of very heavy dark matter components beyond 100 TeV. Non-thermally produced dark matter in this mass range could therefore contribute to the cosmic γ-ray and neutrino flux above 100 TeV, and massive Skyrmions provide an interesting framework for the discussion of these scenarios. Therefore a Higgs portal and a neutrino portal for very heavy Skyrmion dark matter are discussed. The Higgs portal model demonstrates a dark mediator bottleneck, where limitations on particle annihilation cross sections will prevent a signal from the potentially large soliton annihilation cross sections. This problem can be avoided in models where the dark mediator decays. This is illustrated by the neutrino portal for Skyrmion dark matter. (orig.)
Magnetic bilayer-skyrmions without skyrmion Hall effect
Zhang, Xichao; Zhou, Yan; Ezawa, Motohiko
2016-01-01
Magnetic skyrmions might be used as information carriers in future advanced memories, logic gates and computing devices. However, there exists an obstacle known as the skyrmion Hall effect (SkHE), that is, the skyrmion trajectories bend away from the driving current direction due to the Magnus force. Consequently, the skyrmions in constricted geometries may be destroyed by touching the sample edges. Here we theoretically propose that the SkHE can be suppressed in the antiferromagnetically exchange-coupled bilayer system, since the Magnus forces in the top and bottom layers are exactly cancelled. We show that such a pair of SkHE-free magnetic skyrmions can be nucleated and be driven by the current-induced torque. Our proposal provides a promising means to move magnetic skyrmions in a perfectly straight trajectory in ultra-dense devices with ultra-fast processing speed.
Moss, I.G.; Shiiki, N.; Winstanley, E.
2000-01-01
Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.
Current-induced rotational torques in the skyrmion lattice phase of chiral magnets
Everschor, K.; Garst, M.; Duine, R.A.|info:eu-repo/dai/nl/304830127; Rosch, A.
2011-01-01
In chiral magnets without inversion symmetry, the magnetic structure can form a lattice of magnetic whirl lines, a two-dimensional skyrmion lattice, stabilized by spin-orbit interactions in a small range of temperatures and magnetic fields. The twist of the magnetization within this phase gives rise
Pion correlation from Skyrmion--anti-Skyrmion annihilation
International Nuclear Information System (INIS)
Lu, Y.; Amado, R.D.
1995-01-01
We study two pion correlations from Skyrmion and anti-Skyrmion collision, using the product ansatz and an approximate random grooming method for nucleon projection. The spatial-isospin coupling inherent in the Skyrme model, along with empirical averages, leads to correlations not only among pions of like charges but also among unlike charge types
Skyrmions in magnetic multilayers
Energy Technology Data Exchange (ETDEWEB)
Jiang, Wanjun; Chen, Gong; Liu, Kai; Zang, Jiadong; te Velthuis, Suzanne G. E.; Hoffmann, Axel
2017-08-01
Symmetry breaking together with strong spin orbit interaction gives rise to many exciting phenomena within condensed matter physics. A recent example is the existence of chiral spin textures, which are observed in magnetic systems lacking inversion symmetry. These chiral spin textures, including domain walls and magnetic skyrmions, are both fundamentally interesting and technologically promising. For example, they can be driven very efficiently by electrical currents, and exhibit many new physical properties determined by their real-space topological characteristics. Depending on the details of the competing interactions, these spin textures exist in different parameter spaces. However, the governing mechanism underlying their physical behaviors remains essentially the same. In this review article, the fundamental topological physics underlying these chiral spin textures, the key factors for materials optimization, and current developments and future challenges will be discussed. In the end, a few promising directions that will advance the development of skyrmion based spintronics will be highlighted.
Skyrmion dynamics in width-varying nanotracks and implications for skyrmionic applications
Chen, Xing; Kang, Wang; Zhu, Daoqian; Zhang, Xichao; Lei, Na; Zhang, Youguang; Zhou, Yan; Zhao, Weisheng
2017-11-01
A comprehensive study of the magnetic skyrmion dynamics in terms of size, velocity, energy, and stability in width-varying nanotracks is reported by micromagnetic simulations. We find that the diameter of a skyrmion reduces with the decrease in the nanotrack width in the spin Hall effect (SHE)-induced skyrmion motion. Accordingly, the skyrmion energy increases giving rise to the growing instability of the skyrmion. It is also numerically demonstrated that the velocity of the skyrmion varies during the motion, since the repulsive force of the nanotrack edges acting on the skyrmion as well as the driving force created by the SHE associated with the size of the skyrmion have a joint impact on the skyrmion motion dynamics in the width-varying nanotrack. In addition, one interesting finding reveals that skyrmions with small sizes, which may be inaccessible to typical approaches by means of directly injecting a spin-polarized current, could be obtained by utilizing this structure. This finding is potential for generating nanoscale skyrmions in skyrmionic applications with ultra-dense density. Finally, inspired by the skyrmion dynamics in the width-varying nanotrack, a general summary on the tradeoff between the nanotrack width (storage density) and the skyrmion velocity (data access speed) is given by further analyzing the skyrmion dynamics in parallel nanotracks with different widths, which may provide guidelines in designing racetrack-type skyrmionic applications.
Dynamics of current induced nano-skyrmions
Natarajan, Kanimozhi; Rajamani, Amuda; Arumugam, Brinda
2017-08-01
The dynamics of magnetic skyrmions is investigated in a composite free layer spin valve nano pillar for different coupling mechanisms in the absence of Dzyaloshinski-Moriya Interaction (DMI). Nano meter sized skyrmions and anti skyrmions are trapped with different helices in the free layer. The spin polarised current under specific choice of system parameters changes the droplet solitons into skyrmions and anti skyrmions. The current driven dynamics is studied and the condition at which an isolated skyrmion exists, is reported. We have optimised the current density (J) and spin wave vector (k) for which Skyrmion Hall Effect (SHE) completely vanishes and as a result the velocity, size and shape of skyrmions are preserved. When the coupling between the composite free layers is changed, skyrmion-anti skyrmion pair and radial skyrmion-chiral skyrmion pair emerge. For the specific values of 'J' and 'k' these pairs show coupled motion along the layer and hence these pairs could also be used as a bit in the data processing and storage devices. Our investigation ascertains that a single material can host all the localised magnetic structures if the current density, spin wave vector and coupling constant are suitably chosen and tuned. This study would really be of fundamental importance owing to the possible applications in information processing and data storage in skyrmion based logic circuits and magnetic sensors.
Creation of skyrmion through resonance excitation
Energy Technology Data Exchange (ETDEWEB)
Li, Zhi-xiong; Chen, Yi-fu; Zhou, Zhen-wei; Nie, Yao-zhuang; Xia, Qing-lin; Wang, Dao-wei; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn
2017-07-01
Highlights: • Intrinsic oscillation modes of skyrmion are studied by using micromagnetic simulation. • Creation of skyrmion through resonant excitation is proposed. • The number of generated skyrmions can be effectively controlled by manipulating the driving field. • Skyrmion lattice in extended film is generated via resonant excitation. - Abstract: Controllable creation of magnetic skyrmions in nanostructures is a prerequisite for the application of skyrmions in spintronics. Here, we propose a new method for the creation of skyrmions. We show by using micromagnetic simulations that the skyrmions can be nucleated by resonantly exciting one of the skyrmion intrinsic oscillation modes. We first studied the dynamics of skyrmion in a ferromagnetic nanodisk with perpendicular anisotropy. One breathing mode and two non-degenerate gyrotropic modes are identified. Then we applied a circular-polarized microwave field to excite the uniformly magnetized nanodisk. When the frequency of the driving field is equal to the eigenfrequency of the skyrmion gyrotropic mode, stable skyrmions can be created from the initial uniform state. The number of skyrmions can be effectively controlled by appropriately choosing the duration of the driving field or tuning the field amplitude.
Skyrmion-Anti-Skyrmion Pair Creation by in-Plane Currents
Stier, Martin; Häusler, Wolfgang; Posske, Thore; Gurski, Gregor; Thorwart, Michael
2017-06-01
Magnetic Skyrmions can be considered as localized vortexlike spin textures which are topologically protected in continuous systems. Because of their stability, their small size, and the possibility to move them by low electric currents, they are promising candidates for spintronic devices. Without changing the topological charge, it is possible to create Skyrmion-anti-Skyrmion pairs. We derive a Skyrmion equation of motion which reveals how spin-polarized charge currents create Skyrmion-anti-Skyrmion pairs. It allows us to identify general prerequisites for the pair creation process. We corroborate these general principles by numerical simulations. On a lattice, where the concept of topological protection has to be replaced by that of a finite energy barrier, the anti-Skyrmion partner of the pairs is annihilated and only the Skyrmion survives. This eventually changes the total Skyrmion number and yields a new way of creating and controlling Skyrmions.
Energy Technology Data Exchange (ETDEWEB)
Gudnason, Sven Bjarke [Institute of Modern Physics, Chinese Academy of Sciences,Lanzhou 730000 (China); Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University,Hiyoshi 4-1-1, Yokohama, Kanagawa 223-8521 (Japan); Sawado, Nobuyuki [Department of Physics, Tokyo University of Science,Noda, Chiba 278-8510 (Japan)
2015-12-02
The BPS Skyrme model has many exact analytic solutions in flat space. We generalize the model to a curved space or spacetime and find that the solutions can only be BPS for a constant time-time component of the metric tensor. We find exact solutions on the curved spaces: a 3-sphere and a 3-hyperboloid; and we further find an analytic gravitating Skyrmion on the 3-sphere. For the case of a nontrivial time-time component of the metric, we suggest a potential for which we find analytic solutions on anti-de Sitter and de Sitter spacetimes in the limit of no gravitational backreaction. We take the gravitational coupling into account in numerical solutions and show that they are well approximated by the analytic solutions for weak gravitational coupling.
Control of morphology and formation of highly geometrically confined magnetic skyrmions
Jin, Chiming; Li, Zi-An; Kovács, András; Caron, Jan; Zheng, Fengshan; Rybakov, Filipp N.; Kiselev, Nikolai S.; Du, Haifeng; Blügel, Stefan; Tian, Mingliang; Zhang, Yuheng; Farle, Michael; Dunin-Borkowski, Rafal E.
2017-06-01
The ability to controllably manipulate magnetic skyrmions, small magnetic whirls with particle-like properties, in nanostructured elements is a prerequisite for incorporating them into spintronic devices. Here, we use state-of-the-art electron holographic imaging to directly visualize the morphology and nucleation of magnetic skyrmions in a wedge-shaped FeGe nanostripe that has a width in the range of 45-150 nm. We find that geometrically-confined skyrmions are able to adopt a wide range of sizes and ellipticities in a nanostripe that are absent in both thin films and bulk materials and can be created from a helical magnetic state with a distorted edge twist in a simple and efficient manner. We perform a theoretical analysis based on a three-dimensional general model of isotropic chiral magnets to confirm our experimental results. The flexibility and ease of formation of geometrically confined magnetic skyrmions may help to optimize the design of skyrmion-based memory devices.
CSIR Research Space (South Africa)
Forbes, A
2010-12-01
Full Text Available Research at the Mathematical Optics Group uses "twisted" light to study new quatum-based information security systems. In order to understand the structure of "twisted" light, it is useful to start with an ordinary light beam with zero twist, namely...
Rational maps, monopoles and skyrmions
International Nuclear Information System (INIS)
Houghton, C.J.; Manton, N.S.
1998-01-01
We discuss the similarities between BPS monopoles and skyrmions, and point to an underlying connection in terms of rational maps between Riemann spheres. This involves the introduction of a new ansatz for Skyrme fields. We use this to construct good approximations to several known skyrmions, including all the minimal energy configurations up to baryon number nine, and some new solutions such as a baryon number seventeen Skyrme field with the truncated icosahedron structure of a buckyball. The new approach is also used to understand the low-lying vibrational modes of skyrmions, which are required for quantization. Along the way we discover an interesting Morse function on the space of rational maps which may be of use in understanding the Sen forms on the monopole moduli spaces. (orig.)
Dynamics of current induced nano-skyrmions
Energy Technology Data Exchange (ETDEWEB)
Natarajan, Kanimozhi; Rajamani, Amuda, E-mail: amuacademics@gmail.com; Arumugam, Brinda
2017-08-01
Highlights: • We have revised and organised section II. • The expression for H{sub eff} is now expressed clearly. • We have added Appendix which explains the derivation of the solution and the occurrence of the oscillatory factor. - Abstract: The dynamics of magnetic skyrmions is investigated in a composite free layer spin valve nano pillar for different coupling mechanisms in the absence of Dzyaloshinski-Moriya Interaction (DMI). Nano meter sized skyrmions and anti skyrmions are trapped with different helices in the free layer. The spin polarised current under specific choice of system parameters changes the droplet solitons into skyrmions and anti skyrmions. The current driven dynamics is studied and the condition at which an isolated skyrmion exists, is reported. We have optimised the current density (J) and spin wave vector (k) for which Skyrmion Hall Effect (SHE) completely vanishes and as a result the velocity, size and shape of skyrmions are preserved. When the coupling between the composite free layers is changed, skyrmion-anti skyrmion pair and radial skyrmion-chiral skyrmion pair emerge. For the specific values of ‘J’ and ‘k’ these pairs show coupled motion along the layer and hence these pairs could also be used as a bit in the data processing and storage devices. Our investigation ascertains that a single material can host all the localised magnetic structures if the current density, spin wave vector and coupling constant are suitably chosen and tuned. This study would really be of fundamental importance owing to the possible applications in information processing and data storage in skyrmion based logic circuits and magnetic sensors.
Quantum skyrmions in two-dimensional chiral magnets
Takashima, Rina; Ishizuka, Hiroaki; Balents, Leon
2016-10-01
We study the quantum mechanics of magnetic skyrmions in the vicinity of the skyrmion-crystal to ferromagnet phase boundary in two-dimensional magnets. We show that the skyrmion excitation has an energy dispersion that splits into multiple bands due to the combination of magnus force and the underlying lattice. Condensation of the skyrmions can give rise to an intermediate phase between the skyrmion crystal and ferromagnet: a quantum liquid, in which skyrmions are not spatially localized. We show that the critical behavior depends on the spin size S and the topological number of the skyrmion. Experimental signatures of quantum skyrmions in inelastic neutron-scattering measurements are also discussed.
Reversible Vector Ratchet Effect in Skyrmion Systems
Ma, Xiaoyu; Reichhardt, Charles; Reichhardt, Cynthia
Magnetic skyrmions are topological non-trivial spin textures found in several magnetic materials. Since their motion can be controlled using ultralow current densities, skyrmions are appealing for potential applications in spintronics as information carriers and processing devices. In this work, we studied the collective transport properties of driven skyrmions based on a particle-like model with molecular dynamics (MD) simulation. Our results show that ac driven skyrmions interacting with an asymmetric substrate provide a realization of a new class of ratchet system, which we call a vector ratchet, that arises due to the effect of the Magnus term on the skyrmion dynamics. In a vector ratchet, the dc motion induced by the ac drive can be described as a vector that can be rotated up to 360 degrees relative to the substrate asymmetry direction. This could represent a new method for controlling skyrmion motion for spintronic applications.
Skyrmion morphology in ultrathin magnetic films
Gross, I.; Akhtar, W.; Hrabec, A.; Sampaio, J.; Martínez, L. J.; Chouaieb, S.; Shields, B. J.; Maletinsky, P.; Thiaville, A.; Rohart, S.; Jacques, V.
2018-02-01
Nitrogen-vacancy magnetic microscopy is employed in the quenching mode as a noninvasive, high-resolution tool to investigate the morphology of isolated skyrmions in ultrathin magnetic films. The skyrmion size and shape are found to be strongly affected by local pinning effects and magnetic field history. Micromagnetic simulations including a static disorder, based on the physical model of grain-to-grain thickness variations, reproduce all experimental observations and reveal the key role of disorder and magnetic history in the stabilization of skyrmions in ultrathin magnetic films. This work opens the way to an in-depth understanding of skyrmion dynamics in real, disordered media.
Purely electrical detection of a skyrmion in constricted geometry
Energy Technology Data Exchange (ETDEWEB)
Hamamoto, Keita; Ezawa, Motohiko [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nagaosa, Naoto [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198 (Japan)
2016-03-14
How to detect the skyrmion position is a crucial problem in future skyrmionics since it corresponds to the reading process of information. We propose a method to detect the skyrmion position purely electrically by measuring the Hall conductance in a constricted geometry. The Hall conductance becomes maximum when a skyrmion is at the lead position. It is possible to detect the skyrmion position even at room temperature. We find an optimized width of the sample determined by the skyrmion radius. We also investigate the effects of elastic and inelastic scatterings, and finite temperature. Our results will be a basis of future skyrmion electronics.
Quantum Dynamics of Skyrmions in Chiral Magnets
Psaroudaki, Christina; Hoffman, Silas; Klinovaja, Jelena; Loss, Daniel
2017-10-01
We study the quantum propagation of a Skyrmion in chiral magnetic insulators by generalizing the micromagnetic equations of motion to a finite-temperature path integral formalism, using field theoretic tools. Promoting the center of the Skyrmion to a dynamic quantity, the fluctuations around the Skyrmionic configuration give rise to a time-dependent damping of the Skyrmion motion. From the frequency dependence of the damping kernel, we are able to identify the Skyrmion mass, thus providing a microscopic description of the kinematic properties of Skyrmions. When defects are present or a magnetic trap is applied, the Skyrmion mass acquires a finite value proportional to the effective spin, even at vanishingly small temperature. We demonstrate that a Skyrmion in a confined geometry provided by a magnetic trap behaves as a massive particle owing to its quasi-one-dimensional confinement. An additional quantum mass term is predicted, independent of the effective spin, with an explicit temperature dependence which remains finite even at zero temperature.
The effect of the Magnus force on skyrmion relaxation dynamics
Brown, Barton L.; Täuber, Uwe C.; Pleimling, Michel
2018-01-01
We perform systematic Langevin molecular dynamics simulations of interacting skyrmions in thin films. The interplay between Magnus force, repulsive skyrmion-skyrmion interaction and thermal noise yields different regimes during non-equilibrium relaxation. In the noise-dominated regime the Magnus force enhances the disordering effects of the thermal noise. In the Magnus-force-dominated regime, the Magnus force cooperates with the skyrmion-skyrmion interaction to yield a dynamic regime with slo...
Brownian motion of massive skyrmions in magnetic thin films
International Nuclear Information System (INIS)
Troncoso, Roberto E.; Núñez, Álvaro S.
2014-01-01
We report on the thermal effects on the motion of current-driven massive magnetic skyrmions. The reduced equation for the motion of skyrmion has the form of a stochastic generalized Thiele’s equation. We propose an ansatz for the magnetization texture of a non-rigid single skyrmion that depends linearly with the velocity. By using this ansatz it is found that the skyrmion mass tensor is closely related to intrinsic skyrmion parameters, such as Gilbert damping, skyrmion-charge and dissipative force. We have found an exact expression for the average drift velocity as well as the mean-square velocity of the skyrmion. The longitudinal and transverse mobility of skyrmions for small spin-velocity of electrons is also determined and found to be independent of the skyrmion mass
Dynamics of antiferromagnetic skyrmion driven by the spin Hall effect
Jin, Chendong; Song, Chengkun; Wang, Jianbo; Liu, Qingfang
2016-10-01
Magnetic skyrmion moved by the spin-Hall effect is promising for the application of the generation racetrack memories. However, the Magnus force causes a deflected motion of skyrmion, which limits its application. Here, we create an antiferromagnetic skyrmion by injecting a spin-polarized pulse in the nanostripe and investigate the spin Hall effect-induced motion of antiferromagnetic skyrmion by micromagnetic simulations. In contrast to ferromagnetic skyrmion, we find that the antiferromagnetic skyrmion has three evident advantages: (i) the minimum driving current density of antiferromagnetic skyrmion is about two orders smaller than the ferromagnetic skyrmion; (ii) the velocity of the antiferromagnetic skyrmion is about 57 times larger than the ferromagnetic skyrmion driven by the same value of current density; (iii) antiferromagnetic skyrmion can be driven by the spin Hall effect without the influence of Magnus force. In addition, antiferromagnetic skyrmion can move around the pinning sites due to its property of topological protection. Our results present the understanding of antiferromagnetic skyrmion motion driven by the spin Hall effect and may also contribute to the development of antiferromagnetic skyrmion-based racetrack memories.
Dickens, Charles
2005-01-01
Oliver Twist is one of Dickens's most popular novels, with many famous film, television and musical adaptations. It is a classic story of good against evil, packed with humour and pathos, drama and suspense, in which the orphaned Oliver is brought up in a harsh workhouse, and then taken in and
Cooperative Charge Pumping and Enhanced Skyrmion Mobility
Abbout, Adel
2018-04-06
The electronic pumping arising from the steady motion of ferromagnetic skyrmions is investigated by solving the time evolution of the Schrodinger equation implemented on a tight-binding model with the statistical physics of the many-body problem. It is shown that the ability of steadily moving skyrmions to pump large charge currents arises from their non-trivial magnetic topology, i.e. the coexistence between spin-motive force and topological Hall effect. Based on an adiabatic scattering theory, we compute the pumped current and demonstrate that it scales with the reflection coefficient of the conduction electrons against the skyrmion. Finally, we propose that such a phenomenon can be exploited in the context of racetrack devices, where the electronic pumping enhances the collective motion of the train of skyrmions.
Antiferromagnetic Skyrmion: Stability, Creation and Manipulation
Zhang, Xichao; Zhou, Yan; Ezawa, Motohiko
2016-04-01
Magnetic skyrmions are particle-like topological excitations in ferromagnets, which have the topo-logical number Q = ± 1, and hence show the skyrmion Hall effect (SkHE) due to the Magnus force effect originating from the topology. Here, we propose the counterpart of the magnetic skyrmion in the antiferromagnetic (AFM) system, that is, the AFM skyrmion, which is topologically protected but without showing the SkHE. Two approaches for creating the AFM skyrmion have been described based on micromagnetic lattice simulations: (i) by injecting a vertical spin-polarized current to a nanodisk with the AFM ground state; (ii) by converting an AFM domain-wall pair in a nanowire junction. It is demonstrated that the AFM skyrmion, driven by the spin-polarized current, can move straightly over long distance, benefiting from the absence of the SkHE. Our results will open a new strategy on designing the novel spintronic devices based on AFM materials.
Zhang, Yue; Luo, Shijiang; Yan, Baiqian; Ou-Yang, Jun; Yang, Xiaofei; Chen, Shi; Zhu, Benpeng; You, Long
2017-07-27
Magnetic skyrmions have potential applications in novel information devices with excellent energy efficiency. However, the skyrmion Hall effect (SkHE) could cause skyrmions moving in a nanotrack to get annihilated at the track edge. In this work, we discovered that the SkHE is depressed by modifying the magnetic structure at the edge of a track, and thus the skyrmion can move in almost a straight line at a high speed. Unlike the inner part of a track with perpendicular magnetic anisotropy, the edge layer exhibits in-plane magnetic anisotropy, and the orientation of edge moments is opposite that at the perimeter of skyrmions nearby. As a result, an enhanced repulsive force acts on the skyrmion to oppose the Magnus force that causes the SkHE. Additionally, the Dzyaloshinskii-Moriya interaction (DMI) constant of the edge layer also matters. When there is no DMI at the edge layer, the transverse displacement of the skyrmion can be depressed effectively when the width of the edge layer is sufficiently large. However, when the inner part and the edge share the same DMI constant, non-monotonically varied transverse displacement occurs because of the Néel-wall-like structure at the edge layer.
Effect of the Magnus force on skyrmion relaxation dynamics
Brown, Barton L.; Täuber, Uwe C.; Pleimling, Michel
2018-01-01
We perform systematic Langevin molecular dynamics simulations of interacting skyrmions in thin films. The interplay between the Magnus force, the repulsive skyrmion-skyrmion interaction, and the thermal noise yields different regimes during nonequilibrium relaxation. In the noise-dominated regime, the Magnus force enhances the disordering effects of the thermal noise. In the Magnus-force-dominated regime, the Magnus force cooperates with the skyrmion-skyrmion interaction to yield a dynamic regime with slow decaying correlations. These two regimes are characterized by different values of the aging exponent. In general, the Magnus force accelerates the approach to the steady state.
Fluctuations and noise signatures of driven magnetic skyrmions
Díaz, Sebastián A.; Reichhardt, C. J. O.; Arovas, Daniel P.; Saxena, Avadh; Reichhardt, C.
2017-08-01
Magnetic skyrmions are particlelike objects with topologically protected stability which can be set into motion with an applied current. Using a particle-based model we simulate current-driven magnetic skyrmions interacting with random quenched disorder and examine the skyrmion velocity fluctuations parallel and perpendicular to the direction of motion as a function of increasing drive. We show that the Magnus force contribution to skyrmion dynamics combined with the random pinning produces an isotropic effective shaking temperature. As a result, the skyrmions form a moving crystal at large drives instead of the moving smectic state observed in systems with a negligible Magnus force where the effective shaking temperature is anisotropic. We demonstrate that spectral analysis of the velocity noise fluctuations can be used to identify dynamical phase transitions and to extract information about the different dynamic phases, and show how the velocity noise fluctuations are correlated with changes in the skyrmion Hall angle, transport features, and skyrmion lattice structure.
Skyrmions from Instantons inside Domain Walls
International Nuclear Information System (INIS)
Eto, Minoru; Nitta, Muneto; Ohashi, Keisuke; Tong, David
2005-01-01
Some years ago, Atiyah and Manton described a method to construct approximate Skyrmion solutions from Yang-Mills instantons. Here we present a dynamical realization of this construction using domain walls in a five-dimensional gauge theory. The non-Abelian gauge symmetry is broken in each vacuum but restored in the core of the domain wall, allowing instantons to nestle inside the wall. We show that the world volume dynamics of the wall is given by the Skyrme model, including the four-derivative term, and the instantons appear as domain wall Skyrmions
BPS Skyrmions as neutron stars
Directory of Open Access Journals (Sweden)
C. Adam
2015-03-01
Full Text Available The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy–momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the “liquid droplet” model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin–isospin quantization, Coulomb energy, proton–neutron mass difference provide an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather natural proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide excellent results as well as some new perspectives for the description of bulk properties of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value of which depends on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.
Dynamics of skyrmions in chiral magnets: Dynamic phase transitions and equation of motion
Lin, Shi-Zeng; Reichhardt, Charles; Batista, Cristian D.; Saxena, Avadh
2014-05-01
We study the dynamics of skyrmions in a metallic chiral magnet. First, we show that skyrmions can be created dynamically by destabilizing the ferromagnetic background state through a spin polarized current. We then treat skyrmions as rigid particles and derive the corresponding equation of motion. The dynamics of skyrmions is dominated by the Magnus force, which accounts for the weak pinning of skyrmions observed in experiments. Finally, we discuss the quantum motion of skyrmions.
Dynamics of skyrmions in chiral magnets: Dynamic phase transitions and equation of motion
Energy Technology Data Exchange (ETDEWEB)
Lin, Shi-Zeng, E-mail: szl@lanl.gov; Reichhardt, Charles; Batista, Cristian D.; Saxena, Avadh [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2014-05-07
We study the dynamics of skyrmions in a metallic chiral magnet. First, we show that skyrmions can be created dynamically by destabilizing the ferromagnetic background state through a spin polarized current. We then treat skyrmions as rigid particles and derive the corresponding equation of motion. The dynamics of skyrmions is dominated by the Magnus force, which accounts for the weak pinning of skyrmions observed in experiments. Finally, we discuss the quantum motion of skyrmions.
Gateable Skyrmion Transport via Field-induced Potential Barrier Modulation
Fook, Hiu Tung; Gan, Wei Liang; Lew, Wen Siang
2016-02-01
We report on the influence of pinning potentials on current-driven skyrmion dynamics and demonstrate that skyrmions can be gated via either magnetic or electric fields. When encountering pinning potentials, skyrmions are well known to simply skirt around them. However, we show that skyrmions can be depinned much more easily when their driving force is oriented against the pinning site rather that the intuitive option of being oriented away. This observation can be exploited together with the normally undesirable Magnus force for the creation of a skyrmion diode. The phenomenon is explained by the increased skyrmion compression resulting from the spin transfer torque opposing the repulsive potential. The smaller skyrmion size then experiences a reduced pinning potential. For practical low-power device applications, we show that the same skyrmion compression can be recreated by applying either a magnetic or electric field. Our analysis provides an insight on the skyrmion dynamics and manipulation that is critical for the realization of skyrmion-based transistors and low-power memory.
Magnetic stripes and skyrmions with helicity reversals
Yu, Xiuzhen; Mostovoy, Maxim; Tokunaga, Yusuke; Zhang, Weizhu; Kimoto, Koji; Matsui, Yoshio; Kaneko, Yoshio; Nagaosa, Naoto; Tokura, Yoshinori; MacDonald, Allan H.
2012-01-01
It was recently realized that topological spin textures do not merely have mathematical beauty but can also give rise to unique functionalities of magnetic materials. An example is the skyrmion-a nano-sized bundle of noncoplanar spins-that by virtue of its nontrivial topology acts as a flux of
Stabilization of magnetic skyrmions by RKKY interactions
Bezvershenko, Alla V.; Kolezhuk, Alexei K.; Ivanov, Boris A.
2018-02-01
We study the stabilization of an isolated magnetic skyrmion in a magnetic monolayer on a nonmagnetic conducting substrate via the Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction. Two different types of the substrate are considered, usual normal metal and single-layer graphene. While the full stability analysis for skyrmions in the presence of the RKKY coupling requires a separate effort that is outside the scope of this work, we are able to study the radial stability (stability of a skyrmion against collapse) using variational energy estimates obtained within first-order perturbation theory, with the unperturbed Hamiltonian describing the isotropic Heisenberg magnet, and the two perturbations being the RKKY exchange and the easy-axis anisotropy. We show that a proper treatment of the long-range nature of the RKKY interaction leads to a qualitatively different stabilization scenario compared to previous studies, where solitons were stabilized by the frustrated exchange coupling (leading to terms with the fourth power of the magnetization gradients) or by the Dzyaloshinskii-Moriya interaction (described by terms linear in the magnetization gradients). In the case of a metallic substrate, the skyrmion stabilization is possible under restrictive conditions on the Fermi surface parameters, while in the case of a graphene substrate the stabilization is naturally achieved in several geometries with a lattice-matching of graphene and magnetic layer.
Stabilization of magnetic skyrmions by uniaxial tensile strain
Seki, S.; Okamura, Y.; Shibata, K.; Takagi, R.; Khanh, N. D.; Kagawa, F.; Arima, T.; Tokura, Y.
2017-12-01
Magnetic skyrmions with a topological particle nature have recently attracted attention as a potential information carrier for novel magnetic storage devices. For single-phase bulk crystals, skyrmions usually appear for a very narrow temperature region just below the magnetic ordering temperature Tc, and the stabilization of skyrmions for a wider temperature range remains an important challenge. Here, by investigating the impact of uniaxial tensile stress for a chiral magnet Cu2OSeO3 , we demonstrate that only less than 0.2% of uniaxial elongation can dramatically stabilize skyrmions for an entire temperature range from Tc to the lowest temperature. The stability of skyrmions essentially depends on the geometrical relationship among the directions of strain, magnetic field, and crystallographic axes, which is consistently explained in terms of the anisotropic modulation of the Dzyaloshinskii-Moriya interaction and magnetocrystalline anisotropy. Our finding may provide a good strategy for materials design to enhance the stability of skyrmions.
Controlled creation of nanometric skyrmions using external magnetic fields
Mochizuki, Masahito
2017-08-01
To exploit nanometric magnetic skyrmions as information carriers in high-density storage devices, a method is needed that creates an intended number of skyrmions at specified places in the device preferably at a low energy cost. We theoretically propose that using a system with a fabricated hole or notch, the controlled creation of individual skyrmions can be achieved even when using an external magnetic field applied to the entire specimen. The fabricated defect turns out to work like a catalyst to reduce the energy barrier for the skyrmion creation.
An Improved Racetrack Structure for Transporting a Skyrmion
Lai, P.; Zhao, G. P.; Tang, H.; Ran, N.; Wu, S. Q.; Xia, J.; Zhang, X.; Zhou, Y.
2017-03-01
Magnetic skyrmions are promising building blocks for next generation data storage due to their stability, small size and extremely low currents to drive them, which can be used instead of traditional magnetic domain walls to store information as data bits in metalic racetrack memories. However, skyrmions can drift from the direction of electron flow due to the Magnus force and thus may annihilate at the racetrack edges, resulting in the loss of information. Here we propose a new skyrmion-based racetrack structure by adding high-K materials (materials with high magnetic crystalline anisotropy) at the edges, which confines the skyrmions in the center region of the metalic racetrack efficiently. This design can overcome both the clogging and annihilation of skyrmions according to our micromagnetic simulation, which occur normally for skyrmions moving on a racetrack under small and large driving currents, respectively. Phase diagrams for skyrmion motion on the proposed racetrack with various values of current density and racetrack edge width have been calculated and given, showing that skyrmions can be driven at a high speed (about 300 m/s) in the racetrack under relatively smaller driving currents. This design offers the possiblity of building an ultrafast and energy-efficient skyrmion transport device.
The inner topological structure and defect control of magnetic skyrmions
Ren, Ji-Rong; Yu, Zhong-Xi
2017-10-01
We prove that the integrand of magnetic skyrmions can be expressed as curvature tensor of Wu-Yang potential. Taking the projection of the normalized magnetization vector on the 2-dim material surface, and according to Duan's decomposition theory of gauge potential, we reveal that every single skyrmion is just characterized by Hopf index and Brouwer degree at the zero point of this vector field. Our theory meet the results that experimental physicists have achieved by many technologies. The inner topological structure expression of skyrmion with Hopf index and Brouwer degree will be indispensable mathematical basis of skyrmion logic gates.
Directory of Open Access Journals (Sweden)
Dhaded S
1992-01-01
Full Text Available Collodion baby is a rare congenital disorder characterized by parchment like taught membrane covering the whole body. Other findings in our case include ectropion, eversion of lips, and flattening of nose and ears. Skin biopsy showed features consistant with the diagnosis of collodion baby. The child was treated with supportive measures like antibiotics, intravenous fluids, humidification, and application of emollients.
African Journals Online (AJOL)
Prof
2018-01-24
Jan 24, 2018 ... severe exploitation, such as forced labour, slavery, debt bondage, prostitution, pornography or the unlawful removal of organs”. Kalu (2011) in his report on the issue of 'baby factory' in the South East of Nigeria, described 'baby factory' as a form of child trafficking since the girls are harboured against their ...
Avalanches and Criticality in Driven Magnetic Skyrmions
Díaz, S. A.; Reichhardt, C.; Arovas, D. P.; Saxena, A.; Reichhardt, C. J. O.
2018-03-01
We show using numerical simulations that slowly driven Skyrmions interacting with random pinning move via correlated jumps or avalanches. The avalanches exhibit power-law distributions in their duration and size, and the average avalanche shape for different avalanche durations can be scaled to a universal function, in agreement with theoretical predictions for systems in a nonequilibrium critical state. A distinctive feature of Skyrmions is the influence of the nondissipative Magnus term. When we increase the ratio of the Magnus term to the damping term, a change in the universality class of the behavior occurs, the average avalanche shape becomes increasingly asymmetric, and individual avalanches exhibit motion in the direction perpendicular to their own density gradient.
The Skyrmions and quarks in nuclei
International Nuclear Information System (INIS)
Rho, M.
1984-08-01
It is proposed that the quark-bag description and the Skyrmion description of baryons are related to each other by quantized parameters. Topology (through a chiral anomaly) plays an important role in bridging the fundamental theory of the strong interactions (QCD) to effective theories. Some consequences on the efforts to see quark degrees of freedom in nuclear matter are discussed. It is suggested that at low energies there will be no ''smoking gun'' evidences for quark presence in nuclei
Chiral bags, skyrmions and quarks in nuclei
International Nuclear Information System (INIS)
Rho, M.
1984-09-01
Recent developments on an intriguing connection between the quark-bag description of the baryons (nucleons in particular) and the Skyrmion model are discussed in terms of the constraints coming from chiral anomalies. Topics treated are the leaking baryon charge, axial charge and energy density; the role of chiral anomalies; the role of Skyrme's quartic term and the connection to the meson degrees of freedom; and finally some qualitative implications in nuclei. The presentation is purposely descriptive and intuitive instead of mathematically precise
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Mikl, Joanne; Rye, David C
2016-02-01
The twisting somersault is a key skill in diving and gymnastics. The components of twist and somersault are defined with respect to anatomical axes, and combinations of multiples of half rotations of twist and somersault define specific twisting somersault skills. To achieve a twisting somersault skill twist must be continuous; otherwise oscillations in twist while somersaulting may be observed. The posture-dependent inertial properties of the athlete and the initial conditions determine if continuous or oscillating twist is observed. The paper derives equations for the amount of somersault required per half twist, or per twist oscillation, without making assumptions about the relative magnitudes of the moments of inertia. From these equations the skills achievable may be determined. The error associated with the common assumption that the medial and transverse principal moments of inertia are equal is explored. It is concluded that the error grows as the number of twists per somersault decreases, when the medial and transverse moments of inertia diverge, and when the longitudinal moment of inertia approaches either the medial or transverse moment of inertia. Inertial property data for an example athlete are used to illustrate the various rotational states that can occur. Copyright © 2015 Elsevier B.V. All rights reserved.
Collective Transport Properties of Driven Skyrmions with Random Disorder
Reichhardt, C.; Ray, D.; Reichhardt, C. J. Olson
2015-05-01
We use particle-based simulations to examine the static and driven collective phases of Skyrmions interacting with random quenched disorder. We show that nondissipative effects due to the Magnus term reduce the depinning threshold and strongly affect the Skyrmion motion and the nature of the dynamic phases. The quenched disorder causes the Hall angle to become drive dependent in the moving Skyrmion phase, while different flow regimes produce distinct signatures in the transport curves. For weak disorder, the Skyrmions form a pinned crystal and depin elastically, while for strong disorder the system forms a pinned amorphous state that depins plastically. At high drives the Skyrmions can dynamically reorder into a moving crystal, with the onset of reordering determined by the strength of the Magnus term.
Meljanac, Daniel; Meljanac, Stjepan; Mignemi, Salvatore; Pikutić, Danijel; Štrajn, Rina
2018-03-01
We construct the twist operator for the Snyder space. Our starting point is a non-associative star product related to a Hermitian realisation of the noncommutative coordinates originally introduced by Snyder. The corresponding coproduct of momenta is non-coassociative. The twist is constructed using a general definition of the star product in terms of a bi-differential operator in the Hopf algebroid approach. The result is given by a closed analytical expression. We prove that this twist reproduces the correct coproducts of the momenta and the Lorentz generators. The twisted Poincaré symmetry is described by a non-associative Hopf algebra, while the twisted Lorentz symmetry is described by the undeformed Hopf algebra. This new twist might be important in the construction of different types of field theories on Snyder space.
Guided current-induced skyrmion motion in 1D potential well.
Purnama, I; Gan, W L; Wong, D W; Lew, W S
2015-05-29
Magnetic skyrmions are particle-like magnetization configurations which can be found in materials with broken inversion symmetry. Their topological nature allows them to circumvent around random pinning sites or impurities as they move within the magnetic layer, which makes them interesting as information carriers in memory devices. However, when the skyrmion is driven by a current, a Magnus force is generated which leads to the skyrmion moving away from the direction of the conduction electron flow. The deflection poses a serious problem to the realization of skyrmion-based devices, as it leads to skyrmion annihilation at the film edges. Here, we show that it is possible to guide the movement of the skyrmion and prevent it from annihilating by surrounding and compressing the skyrmion with strong local potential barriers. The compressed skyrmion receives higher contribution from the spin transfer torque, which results in the significant increase of the skyrmion speed.
Noise Fluctuations and Avalanche Statistics of Skyrmions with Quenched Disorder
Diaz, Sebastian; Olson Reichhardt, Cynthia; Reichhardt, Charles; Saxena, Avadh
Magnetic skyrmions are nanoscopic magnetic textures that enjoy topologically-protected stability and exhibit particle-like behavior. Their novel transport properties have generated extensive basic research and show great potential for using skyrmions as information carriers in future high-density magnetic storage and logic devices. At the particle level, both magnetic skyrmions and superconducting vortices - another kind of topological excitations that also behave as particles - admit a common theoretical description. While in real materials, superconducting vortex dynamics is dissipation-dominated, the so-called Magnus force dominates the dynamics of magnetic skyrmions. Using a particle-based model, we simulate two different systems in the presence of quenched disorder: velocity noise fluctuations of current-driven skyrmions and avalanche statistics of flux-driven skyrmions. We obtain the power spectral density, dynamical phase diagram, as well as the avalanche critical exponents as a function of the Magnus force strength. Our results show that both the noise and avalanche properties of skyrmions depart significantly from the known case of superconducting vortices.
Voltage Controlled Magnetic Skyrmion Motion for Racetrack Memory.
Kang, Wang; Huang, Yangqi; Zheng, Chentian; Lv, Weifeng; Lei, Na; Zhang, Youguang; Zhang, Xichao; Zhou, Yan; Zhao, Weisheng
2016-03-15
Magnetic skyrmion, vortex-like swirling topologically stable spin configurations, is appealing as information carrier for future nanoelectronics, owing to the stability, small size and extremely low driving current density. One of the most promising applications of skyrmion is to build racetrack memory (RM). Compared to domain wall-based RM (DW-RM), skyrmion-based RM (Sky-RM) possesses quite a few benefits in terms of energy, density and speed etc. Until now, the fundamental behaviors, including nucleation/annihilation, motion and detection of skyrmion have been intensively investigated. However, one indispensable function, i.e., pinning/depinning of skyrmion still remains an open question and has to be addressed before applying skyrmion for RM. Furthermore, Current research mainly focuses on physical investigations, whereas the electrical design and evaluation are still lacking. In this work, we aim to promote the development of Sky-RM from fundamental physics to realistic electronics. First, we investigate the pinning/depinning characteristics of skyrmion in a nanotrack with the voltage-controlled magnetic anisotropy (VCMA) effect. Then, we propose a compact model and design framework of Sky-RM for electrical evaluation. This work completes the elementary memory functionality of Sky-RM and fills the technical gap between the physicists and electronic engineers, making a significant step forward for the development of Sky-RM.
Generalised twisted partition functions
Petkova, V B
2001-01-01
We consider the set of partition functions that result from the insertion of twist operators compatible with conformal invariance in a given 2D Conformal Field Theory (CFT). A consistency equation, which gives a classification of twists, is written and solved in particular cases. This generalises old results on twisted torus boundary conditions, gives a physical interpretation of Ocneanu's algebraic construction, and might offer a new route to the study of properties of CFT.
Twisted network programming essentials
Fettig, Abe
2005-01-01
Twisted Network Programming Essentials from O'Reilly is a task-oriented look at this new open source, Python-based technology. The book begins with recommendations for various plug-ins and add-ons to enhance the basic package as installed. It then details Twisted's collection simple network protocols, and helper utilities. The book also includes projects that let you try out the Twisted framework for yourself. For example, you'll find examples of using Twisted to build web services applications using the REST architecture, using XML-RPC, and using SOAP. Written for developers who want to s
Electrical detection of single magnetic skyrmion at room temperature
Directory of Open Access Journals (Sweden)
Riccardo Tomasello
2017-05-01
Full Text Available This paper proposes a protocol for the electrical detection of a magnetic skyrmion via the change of the tunneling magnetoresistive (TMR signal in a three-terminal device. This approach combines alternating spin-transfer torque from both spin-filtering (due to a perpendicular polarizer and spin-Hall effect with the TMR signal. Micromagnetic simulations, used to test and verify such working principle, show that there exists a frequency region particularly suitable for this achievement. This result can be at the basis of the design of a TMR based read-out for skyrmion detection, overcoming the difficulties introduced by the thermal drift of the skyrmion once nucleated.
Nucleon form factors from 5D skyrmions
Energy Technology Data Exchange (ETDEWEB)
Panico, Giuliano [Bethe Center for Theoretical Physics and Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Wulzer, Andrea [Institut de Theorie des Phenomenes Physiques, EPFL, CH-1015 Lausanne (Switzerland)], E-mail: andrea.wulzer@epfl.ch
2009-06-15
Several aspects of hadron physics are well described by a simple 5D effective field theory. Baryons arise in this scenario as 'large' (and therefore calculable) 5D skyrmions. We extend and refine the existing analysis of this 5D soliton, which is fairly non-trivial due to the need of numerical methods. We perform the complete quantization of those collective coordinates which are relevant for computing the static observables like the nucleon form factors. We compare the result with simple expectations about large-N{sub c} QCD and with the experimental data. An agreement within 30% is found.
Systematics of meson-Skyrmion scattering
International Nuclear Information System (INIS)
Mattis, M.P.
1986-02-01
The S-matrix characterizing the scattering of pions from nucleons is calculated in the context of skyrmion models of the nucleon. These are models in which the nucleon is considered a soliton in the field of pions. The spectrum of nucleon and delta resonances in the Skyrme model is calculated and found to be in overall good agreement with Nature. Model-independent sum rules between amplitudes in the same partial wave are derived and examined. An extension of the formalism to the case of three light flavors is presented. 31 refs., 26 figs., 6 tabs
Face Centered Cubic and Hexagonal Close Packed Skyrmion Crystals in Centrosymmetric Magnets
Lin, Shi-Zeng; Batista, Cristian D.
2018-02-01
Skyrmions are disklike objects that typically form triangular crystals in two-dimensional systems. This situation is analogous to the so-called pancake vortices of quasi-two-dimensional superconductors. The way in which Skyrmion disks or "pancake Skyrmions" pile up in layered centrosymmetric materials is dictated by the interlayer exchange. Unbiased Monte Carlo simulations and simple stabilization arguments reveal face centered cubic and hexagonal close packed Skyrmion crystals for different choices of the interlayer exchange, in addition to the conventional triangular crystal of Skyrmion lines. Moreover, an inhomogeneous current induces a sliding motion of pancake Skyrmions, indicating that they behave as effective mesoscale particles.
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Control and manipulation of antiferromagnetic skyrmions in racetrack
Xia, Haiyan; Jin, Chendong; Song, Chengkun; Wang, Jinshuai; Wang, Jianbo; Liu, Qingfang
2017-12-01
Controllable manipulations of magnetic skyrmions are essential for next-generation spintronic devices. Here, the duplication and merging of skyrmions, as well as logical AND and OR functions, are designed in antiferromagnetic (AFM) materials with a cusp or smooth Y-junction structures. The operational time are in the dozens of picoseconds, enabling ultrafast information processing. A key factor for the successful operation is the relatively complex Y-junction structures, where domain walls propagate through in a controlled manner, without significant risks of pinning, vanishing or unwanted depinning of existing domain walls, as well as the nucleation of new domain walls. The motions of a multi-bit, namely the motion of an AFM skyrmion-chain in racetrack, are also investigated. Those micromagnetic simulations may contribute to future AFM skyrmion-based spintronic devices, such as nanotrack memory, logic gates and other information processes.
Performance of synthetic antiferromagnetic racetrack memory: domain wall versus skyrmion
Tomasello, R
2017-06-20
A storage scheme based on racetrack memory, where the information can be coded in a domain or a skyrmion, seems to be an alternative to conventional hard disk drive for high density storage. Here, we perform a full micromagnetic study of the performance of synthetic antiferromagnetic (SAF) racetrack memory in terms of velocity and sensitivity to defects by using experimental parameters. We find that, to stabilize a SAF skyrmion, the Dzyaloshinskii–Moriya interaction in the top and the bottom ferromagnet should have an opposite sign. The velocity of SAF skyrmions and SAF Néel domain walls are of the same order and can reach values larger than 1200 m s−1 if a spin–orbit torque from the spin-Hall effect with opposite sign is applied to both ferromagnets. The presence of disordered anisotropy in the form of randomly distributed grains introduces a threshold current for both SAF skyrmions and SAF domain walls motions.
Comparing the dynamics of skyrmions and superconducting vortices
Olson Reichhardt, C. J.; Lin, S. Z.; Ray, D.; Reichhardt, C.
2014-08-01
Vortices in type-II superconductors have attracted enormous attention as ideal systems in which to study nonequilibrium collective phenomena, since the self-ordering of the vortices competes with quenched disorder and thermal effects. Dynamic effects found in vortex systems include depinning, nonequilibrium phase transitions, creep, structural order-disorder transitions, and melting. Understanding vortex dynamics is also important for applications of superconductors which require the vortices either to remain pinned or to move in a controlled fashion. Recently, topological defects called skyrmions have been realized experimentally in chiral magnets. Here we highlight similarities and differences between skyrmion dynamics and vortex dynamics. Many of the previous ideas and experimental setups that have been applied to superconducting vortices can also be used to study skyrmions. We also discuss some of the differences between the two systems, such as the potentially large contribution of the Magnus force in the skyrmion system that can dramatically alter the dynamics and transport properties.
Degeneracies and fluctuations of Neel skyrmions in confined geometries
Keesman, Rick; Leonov, A. O.; van Dieten, P.; Buhrandt, Stefan; Barkema, G. T.; Fritz, Lars; Duine, R. A.
2015-01-01
The recent discovery of tunable Dzyaloshinskii-Moriya interactions in layered magnetic materials with perpendicular magnetic anisotropy makes them promising candidates for stabilization and manipulation of skyrmions at elevated temperatures. In this article, we use Monte Carlo simulations to
Dynamics of skyrmionic states in confined helimagnetic nanostructures
Beg, Marijan; Albert, Maximilian; Bisotti, Marc-Antonio; Cortés-Ortuño, David; Wang, Weiwei; Carey, Rebecca; Vousden, Mark; Hovorka, Ondrej; Ciccarelli, Chiara; Spencer, Charles S.; Marrows, Christopher H.; Fangohr, Hans
2017-01-01
In confined helimagnetic nanostructures, skyrmionic states in the form of incomplete and isolated skyrmion states can emerge as the ground state in absence of both external magnetic field and magnetocrystalline anisotropy. In this work, we study the dynamic properties (resonance frequencies and corresponding eigenmodes) of skyrmionic states in thin film FeGe disk samples. We employ two different methods in finite-element based micromagnetic simulation: eigenvalue and ringdown method. The eigenvalue method allows us to identify all resonance frequencies and corresponding eigenmodes that can exist in the simulated system. However, using a particular experimentally feasible excitation can excite only a limited set of eigenmodes. Because of that, we perform ringdown simulations that resemble the experimental setup using both in-plane and out-of-plane excitations. In addition, we report the nonlinear dependence of resonance frequencies on the external magnetic bias field and disk sample diameter and discuss the possible reversal mode of skyrmionic states. We compare the power spectral densities of incomplete skyrmion and isolated skyrmion states and observe several key differences that can contribute to the experimental identification of the state present in the sample. We measure the FeGe Gilbert damping, and using its value we determine what eigenmodes can be expected to be observed in experiments. Finally, we show that neglecting the demagnetization energy contribution or ignoring the magnetization variation in the out-of-film direction—although not changing the eigenmode's magnetization dynamics significantly—changes their resonance frequencies substantially. Apart from contributing to the understanding of skyrmionic states physics, this systematic work can be used as a guide for the experimental identification of skyrmionic states in confined helimagnetic nanostructures.
Comparing the dynamics of skyrmions and superconducting vortices
Energy Technology Data Exchange (ETDEWEB)
Olson Reichhardt, C.J., E-mail: cjrx@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lin, S.Z. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ray, D. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Reichhardt, C. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2014-08-15
Highlights: • We describe similarities and differences between skyrmion and vortex dynamics. • The Magnus force can dramatically alter skyrmion transport. • The pinning becomes very weak when the Magnus force is strong. - Abstract: Vortices in type-II superconductors have attracted enormous attention as ideal systems in which to study nonequilibrium collective phenomena, since the self-ordering of the vortices competes with quenched disorder and thermal effects. Dynamic effects found in vortex systems include depinning, nonequilibrium phase transitions, creep, structural order–disorder transitions, and melting. Understanding vortex dynamics is also important for applications of superconductors which require the vortices either to remain pinned or to move in a controlled fashion. Recently, topological defects called skyrmions have been realized experimentally in chiral magnets. Here we highlight similarities and differences between skyrmion dynamics and vortex dynamics. Many of the previous ideas and experimental setups that have been applied to superconducting vortices can also be used to study skyrmions. We also discuss some of the differences between the two systems, such as the potentially large contribution of the Magnus force in the skyrmion system that can dramatically alter the dynamics and transport properties.
Stability of skyrmions on curved surfaces in the presence of a magnetic field
Energy Technology Data Exchange (ETDEWEB)
Carvalho-Santos, V.L., E-mail: vagson.carvalho@usach.cl [Instituto Federal de Educação, Ciência e Tecnologia Baiano - Campus Senhor do Bonfim, Km 04 Estrada da Igara, 48970-000 Senhor do Bonfim, Bahia (Brazil); Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Elias, R.G.; Altbir, D. [Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Fonseca, J.M. [Universidade Federal de Viçosa, Departamento de Física, Avenida Peter Henry Rolfs s/n, 36570-000 Viçosa, MG (Brazil)
2015-10-01
We study the stability and energetics associated to skyrmions appearing as excitations on curved surfaces. Using a continuum model we show that the presence of cylindrically radial and azimuthal fields destabilize the skyrmions that appear in the absence of an external field. Weak fields generate fractional skyrmions while strong magnetic fields yield stable 2π-skyrmions, which have their widths diminished by the magnetic field strength. Under azimuthal fields vortex appears as stable state on the curved surface. - Highlights: • Stability of skyrmions on curved surfaces in the presence of a magnetic field. • Weak fields can destabilize skyrmions. • Strong magnetic fields yield the appearing of 2π-skyrmions. • The width of skyrmions is determined by the curvature and magnetic field strength. • Under azimuthal fields vortex appears as stable states.
Zhang, Senfu
2018-03-29
Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.
Topological trajectories of a magnetic skyrmion with an in-plane microwave magnetic field
Jin, Chendong; Song, Chengkun; Wang, Jinshuai; Xia, Haiyan; Wang, Jianbo; Liu, Qingfang
2017-12-01
Magnetic skyrmions are stable and topologically protected spin textures which have been observed in several chiral magnetic materials, and the resonant excitations of magnetic skyrmions have become a hot research topic for potential applications in future microwave devices. In this work, we investigate in-plane microwave-induced topological dynamics of a magnetic skyrmion in a nanodisk by using micromagnetic simulations. It is found that the resonant excitations of the skyrmion are elliptical dynamics which contain counterclockwise and clockwise modes by applying different frequencies of the microwave field. The conversion between these two elliptical modes is achieved by a transition to linear vibration. In addition, we demonstrate that the off-centered process of the skyrmion can be controlled by applying different phases of the microwave field. Finally, we discuss the different topological excitations of four types of skyrmions. Our results present the understanding of topological skyrmion dynamics and may also provide a method to control skyrmions in nanodevices.
Twisted classical Poincare algebras
International Nuclear Information System (INIS)
Lukierski, J.; Ruegg, H.; Tolstoy, V.N.; Nowicki, A.
1993-11-01
We consider the twisting of Hopf structure for classical enveloping algebra U(g), where g is the inhomogeneous rotations algebra, with explicite formulae given for D=4 Poincare algebra (g=P 4 ). The comultiplications of twisted U F (P 4 ) are obtained by conjugating primitive classical coproducts by F element of U(c)xU(c), where c denotes any Abelian subalgebra of P 4 , and the universal R-matrices for U F (P 4 ) are triangular. As an example we show that the quantum deformation of Poincare algebra recently proposed by Chaichian and Demiczev is a twisted classical Poincare algebra. The interpretation of twisted Poincare algebra as describing relativistic symmetries with clustered 2-particle states is proposed. (orig.)
Kronberg, Max; Soomro, Muhammad Afzal; Top, Jaap
2017-10-01
In this note we extend the theory of twists of elliptic curves as presented in various standard texts for characteristic not equal to two or three to the remaining characteristics. For this, we make explicit use of the correspondence between the twists and the Galois cohomology set H^1\\big({G}_{\\overline{K}/K}, \\operatorname{Aut}_{\\overline{K}}(E)\\big). The results are illustrated by examples.
Twisted radio waves and twisted thermodynamics.
Kish, Laszlo B; Nevels, Robert D
2013-01-01
We present and analyze a gedanken experiment and show that the assumption that an antenna operating at a single frequency can transmit more than two independent information channels to the far field violates the Second Law of Thermodynamics. Transmission of a large number of channels, each associated with an angular momenta 'twisted wave' mode, to the far field in free space is therefore not possible.
Thomsen, Diana; Burova, Tina; Bengtsson, Teresa
2016-01-01
The Baby Hatch is an alternative adoption process. We have re-conceptualized an already existing concept for it to fit into Danish regulations. Additionally, we have created tangible communication materials in the form of a poster and brochure that will help us to communicate the concept in a focus group discussion setup. In this project, we will be analyzing the participants’ reception of the product campaign and an awareness campaign by using a theory that is introduced by Kim Schrøder, nam...
Relaxation dynamics of interacting skyrmions in thin films
Brown, Bart; Pleimling, Michel
Magnetic skyrmions are topologically protected spin textures which were recently observed in certain chiral magnets and thin films. Skyrmions can be moved by very low current densities which makes them very promising in spintronic applications such as data storage devices and logic gates. A thorough understanding of the relaxation processes for systems of interacting skyrmions far from equilibrium could prove invaluable in real world applications but is currently lacking in the literature. The dynamics are described by the Landau-Lifshitz-Gilbert (LLG) equation, however, simulating many interacting skyrmions by solving the LLG equation is computationally infeasible. We employ a suitable two-dimensional particle based model derived from Thiele's approach to study the two-time density correlation function and other quantities. The particle model differs most notably from similar models which describe vortices in type-II superconductors by the addition of the Magnus force which points perpendicular to the skyrmion velocity in the plane. Numerical studies reveal non-universal scaling of the correlation function where the scaling exponent is a function of the ratio of the Magnus force strength to damping coefficient as well as of the Gaussian noise. This research is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-09ER46613.
Topological mass of magnetic Skyrmions probed by ultrafast dynamic imaging
International Nuclear Information System (INIS)
Buettner, Felix
2013-01-01
In this thesis, we investigate the GHz dynamics of skyrmionic spin structures by means of pump-probe dynamic imaging to determine the equation of motion that governs the behavior of these technologically relevant spin structures. To achieve this goal, we first designed and optimized a perpendicular magnetic anisotropy CoB/Pt multilayer material for low magnetic pinning, as required for ultrafast pump-probe imaging experiments. Second, we developed an integrated sample design for X-ray holography capable of tracking relative magnetic positional changes down to 3 nm spatial resolution. These advances enabled us to image the trajectory of a single magnetic Skyrmion. We find that the motion is comprised of two gyrotropic modes, one clockwise and one counterclockwise. The existence of two modes shows that Skyrmions are massive quasiparticles. From their derived frequencies we find an inertial mass for the Skyrmion which is a factor of five larger than expected based on existing models for inertia in magnetism. Our results demonstrate that the mass of Skyrmions is based on a novel mechanism emerging from their confined nature, which is a direct consequence of their topology.
Magnetic skyrmions: advances in physics and potential applications
Fert, Albert; Reyren, Nicolas; Cros, Vincent
2017-07-01
Magnetic skyrmions are small swirling topological defects in the magnetization texture. Their stabilization and dynamics depend strongly on their topological properties. In most cases, they are induced by chiral interactions between atomic spins in non-centrosymmetric magnetic compounds or in thin films with broken inversion symmetry. Skyrmions can be extremely small, with diameters in the nanometre range, and behave as particles that can be moved, created and annihilated, which makes them suitable for 'abacus'-type applications in information storage and logic technologies. Until recently, skyrmions had been observed only at low temperature and, in most cases, under large applied magnetic fields. An intense research effort has led to the identification of thin-film and multilayer structures in which skyrmions are now stable at room temperature and can be manipulated by electrical currents. The development of skyrmion-based topological spintronics holds promise for applications in the mid-term furure, even though many challenges, such as the achievement of writing, processing and reading functionalities at room temperature and in all-electrical manipulation schemes, still lie ahead.
Particle model for skyrmions in metallic chiral magnets: Dynamics, pinning, and creep
Lin, Shi-Zeng; Reichhardt, Charles; Batista, Cristian D.; Saxena, Avadh
2013-06-01
Recently spin textures called skyrmions have been discovered in certain chiral magnetic materials without spatial inversion symmetry, and they have attracted enormous attention due to their promising application in spintronics since only a low applied current is necessary to drive their motion. When a conduction electron moves around the skyrmion, its spin is fully polarized by the spin texture and acquires a quantized phase; thus, the skyrmion yields an emergent electrodynamics that in turn determines skyrmion motion and gives rise to a finite Hall angle. As topological excitations, skyrmions behave as particles. In this paper we derive the equation of motion for skyrmions as rigid point particles from a microscopic continuum model and obtain the short-range interaction between skyrmions and the interaction between skyrmions and defects. Skyrmions also experience a Magnus force perpendicular to their velocity due to the underlying emergent electromagnetic field. We validate the equation of motion by studying the depinning transition using both the particle and the continuum models. By using the particle description, we explain the recent experimental observations of the rotation of a skyrmion lattice in the presence of a temperature gradient. We also predict quantum and thermal creep motion of skyrmions in the pinning potential.
Tunable room-temperature magnetic skyrmions in Ir/Fe/Co/Pt multilayers
Soumyanarayanan, Anjan; Raju, M.; Gonzalez Oyarce, A. L.; Tan, Anthony K. C.; Im, Mi-Young; Petrović, A. P.; Ho, Pin; Khoo, K. H.; Tran, M.; Gan, C. K.; Ernult, F.; Panagopoulos, C.
2017-09-01
Magnetic skyrmions are nanoscale topological spin structures offering great promise for next-generation information storage technologies. The recent discovery of sub-100-nm room-temperature (RT) skyrmions in several multilayer films has triggered vigorous efforts to modulate their physical properties for their use in devices. Here we present a tunable RT skyrmion platform based on multilayer stacks of Ir/Fe/Co/Pt, which we study using X-ray microscopy, magnetic force microscopy and Hall transport techniques. By varying the ferromagnetic layer composition, we can tailor the magnetic interactions governing skyrmion properties, thereby tuning their thermodynamic stability parameter by an order of magnitude. The skyrmions exhibit a smooth crossover between isolated (metastable) and disordered lattice configurations across samples, while their size and density can be tuned by factors of two and ten, respectively. We thus establish a platform for investigating functional sub-50-nm RT skyrmions, pointing towards the development of skyrmion-based memory devices.
Electrical detection of magnetic skyrmions by tunnelling non-collinear magnetoresistance
Hanneken, Christian; Otte, Fabian; Kubetzka, André; Dupé, Bertrand; Romming, Niklas; von Bergmann, Kirsten; Wiesendanger, Roland; Heinze, Stefan
2015-12-01
Magnetic skyrmions are localized non-collinear spin textures with a high potential for future spintronic applications. Skyrmion phases have been discovered in a number of materials and a focus of current research is to prepare, detect and manipulate individual skyrmions for implementation in devices. The local experimental characterization of skyrmions has been performed by, for example, Lorentz microscopy or atomic-scale tunnel magnetoresistance measurements using spin-polarized scanning tunnelling microscopy. Here we report a drastic change of the differential tunnel conductance for magnetic skyrmions that arises from their non-collinearity: mixing between the spin channels locally alters the electronic structure, which makes a skyrmion electronically distinct from its ferromagnetic environment. We propose this tunnelling non-collinear magnetoresistance as a reliable all-electrical detection scheme for skyrmions with an easy implementation into device architectures.
The influence of the edge effect on the skyrmion generation in a magnetic nanotrack
Directory of Open Access Journals (Sweden)
N. Ran
2017-02-01
Full Text Available Magnetic skyrmions might be used for building next-generation nanomagnetic and spintronic devices, as they have several perspective properties, such as topologically protected stability, nanoscale size, and ultra-low depinning current density. Here we study the influence of the edge effect on the current-induced generation of a magnetic skyrmion in a finite-length thin-film ferromagnetic nanotrack with interface-induced Dzyaloshinskii-Moriya interaction. It shows that a stable skyrmion or a bunch of skyrmions can be successfully generated as long as the distance between the current injection region and the nanotrack terminal is larger than a certain threshold. We investigate the failed skyrmion generation caused by the edge effect, which will lead to an error writing event. We also present the phase diagrams of the skyrmion generation obtained for different material and geometric parameters. Our results could be useful for designing skyrmion-based information storage devices.
The influence of the edge effect on the skyrmion generation in a magnetic nanotrack
Ran, N.; Zhao, G. P.; Tang, H.; Shen, L. C.; Lai, P.; Xia, J.; Zhang, X.; Zhou, Y.
2017-02-01
Magnetic skyrmions might be used for building next-generation nanomagnetic and spintronic devices, as they have several perspective properties, such as topologically protected stability, nanoscale size, and ultra-low depinning current density. Here we study the influence of the edge effect on the current-induced generation of a magnetic skyrmion in a finite-length thin-film ferromagnetic nanotrack with interface-induced Dzyaloshinskii-Moriya interaction. It shows that a stable skyrmion or a bunch of skyrmions can be successfully generated as long as the distance between the current injection region and the nanotrack terminal is larger than a certain threshold. We investigate the failed skyrmion generation caused by the edge effect, which will lead to an error writing event. We also present the phase diagrams of the skyrmion generation obtained for different material and geometric parameters. Our results could be useful for designing skyrmion-based information storage devices.
Full Text Available ... Frequently asked questions Email sign up Join our online community Home > Baby > Feeding your baby Feeding your baby E-mail to a friend Please fill in all fields. Please enter a ...
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... if necessary, and prescribe the best treatment. Handling Baby's Food Safely... Protect your baby and young children by ... the safety button on the lid of commercial baby-food jars is down. If the jar lid doesn' ...
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Full Text Available ... Frequently asked questions Email sign up Join our online community March for Babies Nacersano Share Your Story ... Frequently asked questions Email sign up Join our online community Home > Baby > Feeding your baby Feeding your ...
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Organic Baby Food: Better for Baby?
Healthy Lifestyle Infant and toddler health Is organic baby food better for my baby? Answers from Jay L. Hoecker, M.D. Organic foods are grown or processed without synthetic fertilizers or pesticides. Feeding ...
Topological Hall and spin Hall effects in disordered skyrmionic textures
Ndiaye, Papa Birame
2017-02-24
We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.
Coupled breathing modes in one-dimensional Skyrmion lattices
Kim, Junhoe; Yang, Jaehak; Cho, Young-Jun; Kim, Bosung; Kim, Sang-Koog
2018-02-01
We explored strong coupling of dynamic breathing modes in one-dimensional (1D) skyrmion lattices periodically arranged in thin-film nanostrips. The coupled breathing modes exhibit characteristic concave-down dispersions that represent the in-phase high-energy mode at zero wavenumber (k = 0) and the anti-phase low-energy mode at the Brillouin zone boundary (k = kBZ). The band width of the allowed modes increases with decreasing inter-distance between nearest-neighboring skyrmions. Furthermore, the collective breathing modes propagate very well through the thin-film nanostrips, as fast as 200-700 m/s, which propagation is controllable by the strength of magnetic fields applied perpendicularly to the film plane. The breathing modes in 1D skyrmion lattices potentially formed in such nanostrips possibly can be used as information carriers in information processing devices.
Coupled skyrmion sublattices in Cu2OSeO3
Energy Technology Data Exchange (ETDEWEB)
Langner, M.C.; Roy,, S.; Mishra, S. K.; Lee, J. C. T.; Shi,, X. W.; Hossain, M. A.; Chuang, Y.-D.; Seki, S.; Tokura, Y.; Kevan, S. D.; Schoenlein, R. W.
2014-04-18
We report the observation of a skyrmion lattice in the chiral multiferroic insulator Cu2OSeO3 using Cu L3-edge resonant soft x-ray diffraction. We observe the unexpected existence of two distinct skyrmion sub-lattices that arise from inequivalent Cu sites with chemically identical coordination numbers but different magnetically active orbitals . The skyrmion sublattices are rotated with respect to each other implying a long wavelength modulation of the lattice. The modulation vector is controlled with an applied magnetic field, associating this Moir'e-like phase with a continuous phase transition. Our findings will open a new class of science involving manipulation of quantum topological states.
Skyrmionic spin Seebeck effect via dissipative thermomagnonic torques
Kovalev, Alexey A.
2014-06-01
We derive thermomagnonic torque and its "β-type" dissipative correction from the stochastic Landau-Lifshitz-Gilbert equation. The β-type dissipative correction describes viscous coupling between magnetic dynamics and magnonic current and it stems from spin mistracking of the magnetic order. We show that thermomagnonic torque is important for describing temperature gradient induced motion of skyrmions in helical magnets while dissipative correction plays an essential role in generating transverse Magnus force. We propose to detect such skyrmionic motion by employing the transverse spin Seebeck effect geometry.
Intrinsic nonadiabatic topological torque in magnetic skyrmions and vortices
Akosa, Collins Ashu
2017-03-01
We propose that topological spin currents flowing in topologically nontrivial magnetic textures, such as magnetic skyrmions and vortices, produce an intrinsic nonadiabatic torque of the form Tt∼[(∂xm×∂ym)·m]∂ym. We show that this torque, which is absent in one-dimensional domain walls and/or nontopological textures, is responsible for the enhanced nonadiabaticity parameter observed in magnetic vortices compared to one-dimensional textures. The impact of this torque on the motion of magnetic skyrmions is expected to be crucial, especially to determine their robustness against defects and pinning centers.
Colossal spin transfer torque effect on skyrmion along the edge.
Iwasaki, Junichi; Koshibae, Wataru; Nagaosa, Naoto
2014-08-13
We study by the micromagnetic simulations the skyrmion motion along the edge driven by the current transverse to it. We found that (i) the velocity is enhanced by the factor of ∼ 1/α (α: the Gilbert damping) with the maximum value determined only by the confining force from the edge, (ii) the inertia appear due to the confining potential with the coordinate perpendicular to the edge playing the role of the kinetic momentum, and (iii) the collision between the two skyrmions is almost elastic without causing any internal distortions.
DEFF Research Database (Denmark)
Yiu, Man Lung; Jensen, Christian Søndergaard; Xuegang, Huang
2008-01-01
-based matching generally fall short in offering practical query accuracy guarantees. Our proposed framework, called SpaceTwist, rectifies these shortcomings for k nearest neighbor (kNN) queries. Starting with a location different from the user's actual location, nearest neighbors are retrieved incrementally...
Twisted Winged Endoparasitoids
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 10. Twisted Winged Endoparasitoids - An Enigma for Entomologists. Alpana Mazumdar. General Article Volume 9 Issue 10 October 2004 pp 19-24. Fulltext. Click here to view fulltext PDF. Permanent link:
Unraveling skyrmion spin texture using resonant soft x-ray scattering
Roy, Sujoy
2015-03-01
The recent discovery of skyrmions, that were originally predicted in context of high energy physics, in magnetic materials has sparked tremendous interest in the research community due to its rich physics and potential in spintronics applications. Skyrmions have an unusual spin texture that manifests as magnetic knot and can be easily moved around. Understanding the fundamental physics and mechanisms for controlling their dynamical properties presents important scientific challenges. So far experimental verifications of the skyrmions in magnetic systems have come from neutron scattering and Lorentz transmission electron microscopy (TEM) measurements. In this talk we report the first observation of the skyrmions using resonant soft x-ray scattering. We have used soft x-rays tuned to the Cu L3 edge to diffract off the skyrmion lattice in a multiferroic Cu2OSeO3 compound. We show that in Cu2OSeO3 there exist two skyrmion lattices arising due to the two inequivalent Cu-O sublattices that have two different magnetically active d-orbitals. The two skyrmion sublattices are mutually rotated with respect to each other. The angle of rotation could be changed by an external magnetic field, thereby indicating possible existence of a new phase. We have also studied skyrmion spin texture in an ultra-thin Fe/Gd multilayer that shows perpendicular anisotropy. The Fe/Gd sample exhibits a near perfect aligned stripe phase. Within a small range of temperature and magnetic field we observe a hexagonal scattering pattern due to skyrmion bubbles. Analysis of the scattering pattern suggests that the skyrmion lattice unit cell contains two skyrmions. The biskyrmion state is also revealed by Lorentz TEM images. The near room temperature discovery of skyrmion in a technology relevant material is a significant step towards using skyrmions in magnetic devices. Work at LBNL was supported by the Office of Basic Energy Sciences of the U.S. Department of Energy (Contract No. DE-AC02-05CH11231).
Full Text Available ... In This Topic Breastfeeding help Breastfeeding is best Food allergies and baby Formula feeding How to breastfeed Keeping a breastfeeding log Keeping breast milk safe and healthy Problems and discomforts when breastfeeding Starting your baby on solid foods Using a breast pump Baby Feeding your baby ...
Fractional instantons and bions in the O(N) model with twisted boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University,Hiyoshi 4-1-1, Yokohama, Kanagawa 223-8521 (Japan)
2015-03-20
Recently, multiple fractional instanton configurations with zero instanton charge, called bions, have been revealed to play important roles in quantum field theories on compactified spacetime. In two dimensions, fractional instantons and bions have been extensively studied in the ℂP{sup N−1} model and the Grassmann sigma model on ℝ{sup 1}×S{sup 1} with the ℤ{sub N} symmetric twisted boundary condition. Fractional instantons in these models are domain walls with a localized U(1) modulus twisted half along their world volume. In this paper, we classify fractional instantons and bions in the O(N) nonlinear sigma model on ℝ{sup N−2}×S{sup 1} with more general twisted boundary conditions in which arbitrary number of fields change sign. We find that fractional instantons have more general composite structures, that is, a global vortex with an Ising spin (or a half-lump vortex), a half sine-Gordon kink on a domain wall, or a half lump on a “space-filling brane” in the O(3) model (ℂP{sup 1} model) on ℝ{sup 1}×S{sup 1}, and a global monopole with an Ising spin (or a half-Skyrmion monopole), a half sine-Gordon kink on a global vortex, a half lump on a domain wall, or a half Skyrmion on a “space-filling brane” in the O(4) model (principal chiral model or Skyrme model) on ℝ{sup 2}×S{sup 1}. We also construct bion configurations in these models.
Full Text Available ... Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & birth Postpartum care Baby ... Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & birth Postpartum care Baby ...
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Brain, Helen
This book for beginning readers tells the story of a South African priest and his wife who are ashamed when their daughter tells them she is going to have a baby. They refuse to have anything to do with her when she is pregnant. However, when the baby comes, everything changes and they come to accept and love the baby. Large black and white…
Aschieri, Paolo; Dimitrijević, Marija; Meyer, Frank; Schraml, Stefan; Wess, Julius
2006-10-01
Gauge theories on a space-time that is deformed by the Moyal-Weyl product are constructed by twisting the coproduct for gauge transformations. This way a deformed Leibniz rule is obtained, which is used to construct gauge invariant quantities. The connection will be enveloping algebra valued in a particular representation of the Lie algebra. This gives rise to additional fields, which couple only weakly via the deformation parameter θ and reduce in the commutative limit to free fields. Consistent field equations that lead to conservation laws are derived and some properties of such theories are discussed.
Twisting of paramodular vectors
Johnson-Leung, Jennifer; Roberts, Brooks
2013-01-01
Let $F$ be a non-archimedean local field of characteristic zero, let $(\\pi,V)$ be an irreducible, admissible representation of $\\GSp(4,F)$ with trivial central character, and let $\\chi$ be a quadratic character of $F^\\times$ with conductor $c(\\chi)>1$. We define a twisting operator $T_\\chi$ from paramodular vectors for $\\pi$ of level $n$ to paramodular vectors for $\\chi \\otimes \\pi$ of level $\\max(n+2c(\\chi),4c(\\chi))$, and prove that this operator has properties analogous to the well-known $...
Energy Technology Data Exchange (ETDEWEB)
Shindler, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2007-07-15
I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the effects of these discretization errors on the phase structure for Wilson-like fermions in the chiral limit. The possibility to use in lattice simulations different lattice actions for sea and valence quarks to ease the renormalization patterns of phenomenologically relevant local operators, is also discussed. (orig.)
Streamlined approach to mapping the magnetic induction of skyrmionic materials.
Chess, Jordan J; Montoya, Sergio A; Harvey, Tyler R; Ophus, Colin; Couture, Simon; Lomakin, Vitaliy; Fullerton, Eric E; McMorran, Benjamin J
2017-06-01
Recently, Lorentz transmission electron microscopy (LTEM) has helped researchers advance the emerging field of magnetic skyrmions. These magnetic quasi-particles, composed of topologically non-trivial magnetization textures, have a large potential for application as information carriers in low-power memory and logic devices. LTEM is one of a very few techniques for direct, real-space imaging of magnetic features at the nanoscale. For Fresnel-contrast LTEM, the transport of intensity equation (TIE) is the tool of choice for quantitative reconstruction of the local magnetic induction through the sample thickness. Typically, this analysis requires collection of at least three images. Here, we show that for uniform, thin, magnetic films, which includes many skyrmionic samples, the magnetic induction can be quantitatively determined from a single defocused image using a simplified TIE approach. Copyright © 2017 Elsevier B.V. All rights reserved.
Skyrmion clusters from Bloch lines in ferromagnetic films
Garanin, Dmitry A.
2017-12-29
Conditions under which various skyrmion objects emerge in experiments on thin magnetic films remain largely unexplained. We investigate numerically centrosymmetric spin lattices in films of finite thickness with ferromagnetic exchange, magnetic anisotropy, and dipole-dipole interaction. Evolution of labyrinth domains into compact topological structures on application of the magnetic field is found to be governed by the configuration of Bloch lines inside domain walls. Depending on the combination of Bloch lines, the magnetic domains evolve into individual skyrmions, biskyrmions, or more complex topological objects. While the geometry of such objects is sensitive to the parameters, their topological charge is uniquely determined by the topological charge of Bloch lines inside the magnetic domain from which the object emerges.
Skyrmion based universal memory operated by electric current
Energy Technology Data Exchange (ETDEWEB)
Zang, Jiadong; Chien, Chia-Ling; Li, Yufan; Lake, Roger K.; Yin, Gen
2017-09-26
A method for generating a skyrmion, comprising: depositing a vertical metallic nanopillar electrode on a first side of a helimagnetic thin film, the helimagnetic thin film having a contact on a second side to provide a current drain; injecting a current through the vertical metallic nanopillar electrode to generate a rotating field; and applying a static upward magnetic field perpendicular to the helimagnetic thin film to maintain an FM phase background.
Real-space Berry phases: Skyrmion soccer (invited)
Energy Technology Data Exchange (ETDEWEB)
Everschor-Sitte, Karin, E-mail: karin@physics.utexas.edu; Sitte, Matthias [The University of Texas at Austin, Department of Physics, 2515 Speedway, Austin, Texas 78712 (United States)
2014-05-07
Berry phases occur when a system adiabatically evolves along a closed curve in parameter space. This tutorial-like article focuses on Berry phases accumulated in real space. In particular, we consider the situation where an electron traverses a smooth magnetic structure, while its magnetic moment adjusts to the local magnetization direction. Mapping the adiabatic physics to an effective problem in terms of emergent fields reveals that certain magnetic textures, skyrmions, are tailormade to study these Berry phase effects.
Real-space Berry phases: Skyrmion soccer (invited)
Everschor-Sitte, Karin; Sitte, Matthias
2014-05-01
Berry phases occur when a system adiabatically evolves along a closed curve in parameter space. This tutorial-like article focuses on Berry phases accumulated in real space. In particular, we consider the situation where an electron traverses a smooth magnetic structure, while its magnetic moment adjusts to the local magnetization direction. Mapping the adiabatic physics to an effective problem in terms of emergent fields reveals that certain magnetic textures, skyrmions, are tailormade to study these Berry phase effects.
Spinning geometry = Twisted geometry
International Nuclear Information System (INIS)
Freidel, Laurent; Ziprick, Jonathan
2014-01-01
It is well known that the SU(2)-gauge invariant phase space of loop gravity can be represented in terms of twisted geometries. These are piecewise-linear-flat geometries obtained by gluing together polyhedra, but the resulting geometries are not continuous across the faces. Here we show that this phase space can also be represented by continuous, piecewise-flat three-geometries called spinning geometries. These are composed of metric-flat three-cells glued together consistently. The geometry of each cell and the manner in which they are glued is compatible with the choice of fluxes and holonomies. We first remark that the fluxes provide each edge with an angular momentum. By studying the piecewise-flat geometries which minimize edge lengths, we show that these angular momenta can be literally interpreted as the spin of the edges: the geometries of all edges are necessarily helices. We also show that the compatibility of the gluing maps with the holonomy data results in the same conclusion. This shows that a spinning geometry represents a way to glue together the three-cells of a twisted geometry to form a continuous geometry which represents a point in the loop gravity phase space. (paper)
Twisting perturbed parafermions
Directory of Open Access Journals (Sweden)
A.V. Belitsky
2017-07-01
Full Text Available The near-collinear expansion of scattering amplitudes in maximally supersymmetric Yang–Mills theory at strong coupling is governed by the dynamics of stings propagating on the five sphere. The pentagon transitions in the operator product expansion which systematize the series get reformulated in terms of matrix elements of branch-point twist operators in the two-dimensional O(6 nonlinear sigma model. The facts that the latter is an asymptotically free field theory and that there exists no local realization of twist fields prevents one from explicit calculation of their scaling dimensions and operator product expansion coefficients. This complication is bypassed making use of the equivalence of the sigma model to the infinite-level limit of WZNW models perturbed by current–current interactions, such that one can use conformal symmetry and conformal perturbation theory for systematic calculations. Presently, to set up the formalism, we consider the O(3 sigma model which is reformulated as perturbed parafermions.
Stolt, Matthew J; Li, Zi-An; Phillips, Brandon; Song, Dongsheng; Mathur, Nitish; Dunin-Borkowski, Rafal E; Jin, Song
2017-01-11
Magnetic skyrmions are topologically stable vortex-like spin structures that are promising for next generation information storage applications. Materials that host magnetic skyrmions, such as MnSi and FeGe with the noncentrosymmetric cubic B20 crystal structure, have been shown to stabilize skyrmions upon nanostructuring. Here, we report a chemical vapor deposition method to selectively grow nanowires (NWs) of cubic FeGe out of three possible FeGe polymorphs for the first time using finely ground particles of cubic FeGe as seeds. X-ray diffraction and transmission electron microscopy (TEM) confirm that these micron-length NWs with ∼100 nm to 1 μm diameters have the cubic B20 crystal structure. Although Fe 13 Ge 8 NWs are also formed, the two types of NWs can be readily differentiated by their faceting. Lorentz TEM imaging of the cubic FeGe NWs reveals a skyrmion lattice phase under small applied magnetic fields (∼0.1 T) at 233 K, a skyrmion chain state at lower temperatures (95 K) and under high magnetic fields (∼0.4 T), and a larger skyrmion stability window than bulk FeGe. This synthetic approach to cubic FeGe NWs that support stabilized skyrmions opens a route toward the exploration of new skyrmion physics and devices based on similar nanostructures.
Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate
Reichhardt, C.; Reichhardt, C. J. Olson
2016-09-01
We numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.
Novak, R. L.; Garcia, F.; Novais, E. R. P.; Sinnecker, J. P.; Guimarães, A. P.
2018-04-01
Skyrmions are emerging topological spin structures that are potentially revolutionary for future data storage and spintronics applications. The existence and stability of skyrmions in magnetic materials is usually associated to the presence of the Dzyaloshinskii-Moriya interaction (DMI) in bulk magnets or in magnetic thin films lacking inversion symmetry. While some methods have already been proposed to generate isolated skyrmions in thin films with DMI, a thorough study of the conditions under which the skyrmions will remain stable in order to be manipulated in an integrated spintronic device are still an open problem. The stability of such structures is believed to be a result of ideal combinations of perpendicular magnetic anisotropy (PMA), DMI and the interplay between geometry and magnetostatics. In the present work we show some micromagnetic results supporting previous experimental observations of magnetic skyrmions in spin-valve stacks with a wide range of DMI values. Using micromagnetic simulations of cobalt-based disks, we obtain the magnetic ground state configuration for several values of PMA, DMI and geometric parameters. Skyrmion numbers, corresponding to the topological charge, are calculated in all cases and confirm the occurrence of isolated, stable, axially symmetric skyrmions for several combinations of DMI and anisotropy constant. The stability of the skyrmions in disks is then investigated under magnetic field and spin-polarized current, in finite temperature, highlighting the limits of applicability of these spin textures in spintronic devices.
DEFF Research Database (Denmark)
Randrup, Thomas; Røgen, Peter
1997-01-01
is an invariant of ambient isotopy measuring the topological twist of the closed strip. We classify closed strips in euclidean 3-space by their knots and their twisting number. We prove that this classification exactly divides closed strips into isotopy classes. Using this classification we point out how some...
DEFF Research Database (Denmark)
Randrup, Thomas; Røgen, Peter
1996-01-01
is an invariant of ambient isotopy measuring the topological twist of the closed strip. We classify closed strips in euclidean 3-space by their knots and their twisting number. We prove that this classification exactly divides closed strips into isotopy classes. Using this classification we point out how some...
Twisting formula of epsilon factors
Indian Academy of Sciences (India)
For characters of a non-Archimedean local field we have explicit formula for epsilon factors. But in general, we do not have any generalized twisting formula of epsilon factors. In this paper, we give a generalized twisting formula of epsilon factorsvia local Jacobi sums.
Quantized transport for a skyrmion moving on a two-dimensional periodic substrate
Reichhardt, C.; Ray, D.; Reichhardt, C. J. Olson
2015-03-01
We examine the dynamics of a skyrmion moving over a two-dimensional periodic substrate utilizing simulations of a particle-based skyrmion model. We specifically examine the role of the nondissipative Magnus term on the driven motion and the resulting skyrmion velocity-force curves. In the overdamped limit, there is a depinning transition into a sliding state in which the skyrmion moves in the same direction as the external drive. When there is a finite Magnus component in the equation of motion, a skyrmion in the absence of a substrate moves at an angle with respect to the direction of the external driving force. When a periodic substrate is added, the direction of motion or Hall angle of the skyrmion is dependent on the amplitude of the external drive, only approaching the substrate-free limit for higher drives. Due to the underlying symmetry of the substrate the direction of skyrmion motion does not change continuously as a function of drive, but rather forms a series of discrete steps corresponding to integer or rational ratios of the velocity components perpendicular ( ) and parallel ( ) to the external drive direction: / =n /m , where n and m are integers. The skyrmion passes through a series of directional locking phases in which the motion is locked to certain symmetry directions of the substrate for fixed intervals of the drive amplitude. Within a given directionally locked phase, the Hall angle remains constant and the skyrmion moves in an orderly fashion through the sample. Signatures of the transitions into and out of these locked phases take the form of pronounced cusps in the skyrmion velocity versus force curves, as well as regions of negative differential mobility in which the net skyrmion velocity decreases with increasing external driving force. The number of steps in the transport curve increases when the relative strength of the Magnus term is increased. We also observe an overshoot phenomena in the directional locking, where the skyrmion motion
Origin of temperature and field dependence of magnetic skyrmion size in ultrathin nanodots
Tomasello, R.; Guslienko, K. Y.; Ricci, M.; Giordano, A.; Barker, J.; Carpentieri, M.; Chubykalo-Fesenko, O.; Finocchio, G.
2018-02-01
Understanding the physical properties of magnetic skyrmions is important for fundamental research with the aim to develop new spintronic device paradigms where both logic and memory can be integrated at the same level. Here, we show a universal model based on the micromagnetic formalism that can be used to study skyrmion stability as a function of magnetic field and temperature. We consider ultrathin, circular ferromagnetic magnetic dots. Our results show that magnetic skyrmions with a small radius—compared to the dot radius—are always metastable, while large radius skyrmions form a stable ground state. The change of energy profile determines the weak (strong) size dependence of the metastable (stable) skyrmion as a function of temperature and/or field.
Barker, Joseph; Tretiakov, Oleg A.
2016-04-01
Skyrmions are topologically protected entities in magnetic materials which have the potential to be used in spintronics for information storage and processing. However, Skyrmions in ferromagnets have some intrinsic difficulties which must be overcome to use them for spintronic applications, such as the inability to move straight along current. We show that Skyrmions can also be stabilized and manipulated in antiferromagnetic materials. An antiferromagnetic Skyrmion is a compound topological object with a similar but of opposite sign spin texture on each sublattice, which, e.g., results in a complete cancellation of the Magnus force. We find that the composite nature of antiferromagnetic Skyrmions gives rise to different dynamical behavior due to both an applied current and temperature effects.
Two-fluid model of the Skyrmion
Energy Technology Data Exchange (ETDEWEB)
Ralston, J.P.
1986-04-01
We consider the field-theory description of the Skyrme model incorporating quantum fluctuations of a condensed phase. This viewpoint clarifies the usefulness of the model for applications at the physical value of F/sub ..pi../, rather than F/sub ..pi../..-->..infinity. By creating covariant field-theory states associated with a translational-dependent condensate, we emphasize the effects of fluctuations and coherence in a calculation of the q/sup 2/ dependence of the baryon electromagnetic form factor F(q/sup 2/). Using the impulse approximation at large q/sup 2/, we find the model predicts F(q/sup 2/)approx.exp(-Vertical Barq/sup 2/Vertical Bar/lambda/sup 2/)/q /sup 2/, where lambdaapprox.1 GeV is a calculable scale. Appending a pion form factor of O(1/q/sup 2/), we interpret this in terms of higher-twist corrections, at moderate values of momentum transfer, to a leading term of O(1/q/sup 4/). The dependence on a regularization scale ..mu../sup 2/ and F/sub ..pi../ /sup 2/ is such that this result applies for a specified range of q/sup 2/, ..mu../sup 2/, and F/sub ..pi../ /sup 2/. However, the detailed results of the calculation are such that the large-F/sub ..pi../ /sup 2/ and large-..mu../sup 2/ limits do not commute.
Spin-Orbit Torques and Anisotropic Magnetization Damping in Skyrmion Crystals
Hals, Kjetil; Brataas, Arne
2014-03-01
We theoretically study the effects of reactive and dissipative homogeneous spin-orbit torques and anisotropic damping on the current-driven skyrmion dynamics in cubic chiral magnets. Our results demonstrate that spin-orbit torques play a significant role in the current-induced skyrmion velocity. The dissipative spin-orbit torque generates a relativistic Magnus force on the skyrmions, whereas the reactive spin-orbit torque yields a correction to both the drift velocity along the current direction and the transverse velocity associated with the Magnus force. The spin-orbit torque corrections to the velocity scale linearly with the skyrmion size, which is inversely proportional to the spin-orbit coupling. Consequently, the reactive spin-orbit torque correction can be the same order of magnitude as the non-relativistic contribution. More importantly, the dissipative spin-orbit torque can be the dominant force that causes a deflected motion of the skyrmions if the torque exhibits a linear or quadratic relationship with the spin-orbit coupling. In addition, we demonstrate that the skyrmion velocity is determined by anisotropic magnetization damping parameters governed by the skyrmion size.
Reichhardt, C.; Reichhardt, C. J. Olson
2015-12-01
We numerically study the behavior of two-dimensional skyrmions in the presence of a quasi-one-dimensional sinusoidal substrate under the influence of externally applied dc and ac drives. In the overdamped limit, when both dc and ac drives are aligned in the longitudinal direction parallel to the direction of the substrate modulation, the velocity-force curves exhibit classic Shapiro step features when the frequency of the ac drive matches the washboard frequency that is dynamically generated by the motion of the skyrmions over the substrate, similar to previous observations in superconducting vortex systems. In the case of skyrmions, the additional contribution to the skyrmion motion from a nondissipative Magnus force shifts the location of the locking steps to higher dc drives, and we find that the skyrmions move at an angle with respect to the direction of the dc drive. For a longitudinal dc drive and a perpendicular or transverse ac drive, the overdamped system exhibits no Shapiro steps; however, when a finite Magnus force is present, we find pronounced transverse Shapiro steps along with complex two-dimensional periodic orbits of the skyrmions in the phase-locked regimes. Both the longitudinal and transverse ac drives produce locking steps whose widths oscillate with increasing ac drive amplitude. We examine the role of collective skyrmion interactions and find that additional fractional locking steps occur for both longitudinal and transverse ac drives. At higher skyrmion densities, the system undergoes a series of dynamical order-disorder transitions, with the skyrmions forming a moving solid on the phase locking steps and a fluctuating dynamical liquid in regimes between the steps.
Baby M: babies (and justice) for sale.
Annas, G J
1987-06-01
A professor of health law criticizes the decisions of New Jersey Superior Court Judge Harvey R. Sorkow which culminated in his awarding permanent custody of Baby M to her biological father, William Stern. Annas quotes from the In re Baby M decision and from the contract between Stern and his wife and surrogate mother Mary Beth Whitehead to support his contention that Sorkow "rendered a sermon filled with contradictions, double-standards, inapt analogies, and unsupported conclusions." He argues that legally Mrs. Whitehead could not have prospectively waived her right to rear a child she bore, that Sorkow was biased in favor of the "upper-middle-class Sterns," and that consideration should be given to returning Baby M to Mrs. Whitehead. He urges state legislatures to outlaw the sale of children, to affirm the legal status of the gestational mother, and to forbid a surrogate's relinquishment of parental rights until after her child's birth.
Stosic, Dusan; Ludermir, Teresa B.; Milošević, Milorad V.
2017-12-01
Magnetic skyrmions are nanoscale windings of the spin structure that can be observed in chiral magnets and hold promise for potential applications in storing or processing information. Pinning due to ever-present material imperfections crucially affects the mobility of skyrmions. Therefore, a proper understanding of how magnetic skyrmions pin to defects is necessary for the development and performance of spintronic devices. Here we present a fundamental analysis on the interactions of single skyrmions with atomic defects of distinctly different origins, in a Co monolayer on Pt, based on minimum-energy paths considerations and atomic-spin simulations. We first report the preferred pinning loci of the skyrmion as a function of its nominal size and the type of defect being considered, to further reveal the manipulation and "breathing" of skyrmion core in the vicinity of a defect. We also show the behavior of skyrmions in the presence of an extended defect of particular geometry, that can lead to ratcheted skyrmion motion or a facilitated guidance on a defect "trail." We close the study with reflections on the expected thermal stability of the skyrmion against collapse on itself for a given nature of the defect, and discuss the applications where control of skyrmions by defects is of particular interest.
Photophysics of internal twisting
International Nuclear Information System (INIS)
Heisel, F.; Miehe, J.A.; Lippert, E.; Rettig, W.; Bonacic-Koutecky, V.
1987-01-01
The formation and characteristics of the ''twisted intermolecular charge transfer'' is studied. Basic concepts on dual fluorescence, steady-state fluorescence, kinetic investigations and cage effects are discussed. The theoretical treatment on the electronic structure of the bonded π - donor - π acceptor pairs is outlined. The two-electron, two-orbital model, the ab initio CI models of simple double, charged and dative π - bonds as well as complex dative π - bonds and the origin of the dual fluorescence of 9.9'-Bianthryl are shown. Concerning the stochastic description of chemical reactions, Master equation, Markov, Birth-Death and Diffusion processes, Kramers-Moyal expansion, Langevin equation, Kramers' approach to steady-state rates of reaction and its extension to non-Markovian processes, and also unimolecular reactions in the absence of potential barrier are considered. Experimental results and interpretation on dynamics of DMABN in the excited state, kinetics of other dialkylanilines, extended donor-acceptor systems with anomalous fluorescence and donor-acceptor systems without anomalous fluorescence are given
Casali, Eduardo; Tourkine, Piotr
2018-03-01
Twistor string models have been known for more than a decade now but have come back under the spotlight recently with the advent of the scattering equation formalism which has greatly generalized the scope of these models. A striking ubiquitous feature of these models has always been that, contrary to usual string theory, they do not admit vibrational modes and thus describe only conventional field theory. In this paper we report on the surprising discovery of a whole new sector of one of these theories which we call "twisted strings," when spacetime has compact directions. We find that the spectrum is enhanced from a finite number of states to an infinite number of interacting higher spin massive states. We describe both bosonic and world sheet supersymmetric models, their spectra and scattering amplitudes. These models have distinctive features of both string and field theory, for example they are invariant under stringy T-duality but have the high energy behavior typical of field theory. Therefore they describe a new kind of field theories in target space, sitting on their own halfway between string and field theory.
Skyrmion production on demand by homogeneous DC currents
Czech Academy of Sciences Publication Activity Database
Everschor-Sitte, K.; Sitte, M.; Valet, T.; Abanov, A.; Sinova, Jairo
2017-01-01
Roč. 19, Sep (2017), s. 1-5, č. článku 092001. ISSN 1367-2630 R&D Projects: GA ČR GB14-37427G; GA MŠk EF16_013/0001405 EU Projects: European Commission(XE) 610115 - SC2 Grant - others:OP VVV - LNSM(XE) CZ.02.1.01/0.0/0.0/16_013/0001405 Institutional support: RVO:68378271 Keywords : magnetization dynamics * micromagnetic simulations * skyrmions * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.786, year: 2016
The equation of state of dense Skyrmion matter
International Nuclear Information System (INIS)
Walhout, T.S.
1990-01-01
In the context of effective topological soliton theories of baryonic interactions, methods for determining the thermodynamic properties of dense matter in the solid and liquid states are presented. In particular, simulation involving a face-centered cubic lattice of skyrmions are used to construct the equation of state for dense neutron matter. The implications for neutron star structure are discussed, and comparisons are made with previous calculations. These techniques are also applied with some success to both symmetric and asymmetric nuclear matter in the Skyrme model. Possibilities for further improvement are outlined. (orig.)
Statistics of Skyrmions and the ν=5/2 puzzle
International Nuclear Information System (INIS)
Dziarmaga, J.
1997-01-01
For the hard-core interaction there is some freedom left in the choice of the exact multi-Skyrmionic wave function close-quote s topology. The statistics of textured quasiholes, analyzed by calculation of the Berry phase, depends on this choice of topology. We find a class of textured two-hole eigenstates of the Coulomb interaction. There is no definite quantum statistics, but there is a definite rule of how to construct Coulomb eigenstates out of the hard-core wave functions. A wave function for the 5/2 state is constructed according to this rule. copyright 1997 The American Physical Society
Roper resonances and quasi-normal modes of Skyrmions
Adam, C.; Haberichter, M.; Romanczukiewicz, T.; Wereszczynski, A.
2018-03-01
Radial vibrations of charge one hedgehog Skyrmions in the full Skyrme model are analysed. We investigate how the properties of the lowest resonance modes (quasi normal modes) — their frequencies and widths — depend on the form of the potential (value of the pion mass as well as the addition of further potentials) and on the inclusion of the sextic term. Then we consider the inverse problem, where certain values for the frequencies and widths are imposed, and the field theoretic Skyrme model potential giving rise to them is reconstructed. This latter method allows to reproduce the physical Roper resonances, as well as further physical properties of nucleons, with high precision.
... vomiting, and pale or bluish skin. Shaken baby injuries usually occur in children younger than 2 years old, but may be ... vomiting, and pale or bluish skin. Shaken baby injuries usually occur in children younger than 2 years old, but may be ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics. T P Nafeesa Baby. Articles written in Pramana – Journal of Physics. Volume 80 Issue 2 February 2013 pp 289-294 Research Articles. Plasma excitations in a single-walled carbon nanotube with an external transverse magnetic field · K A Vijayalakshmi T P Nafeesa Baby.
Resuscitation of Newborn Babies
African Journals Online (AJOL)
Ann Burgess
If the baby is still not breathing give inflation breaths – see Box 1. The heart rate usually responds to lung inflation. If there is no heart rate response, check for chest movement. About 95% of babies needing resuscitation will recover within a minute or two once air enters the lungs. • Re-assess. If the lungs are inflating (i.e. the.
... the bath. Most parents start with the baby's face and move down to dirtier parts of the body. This keeps rinsed areas from getting soapy again. If your newborn has hair and you think it needs washing, go ahead. With your free hand gently massage a drop of mild baby shampoo into your ...
Full Text Available ... your baby Feeding your baby E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's ... Sign up to save this page. Saving Just a moment, please. You've saved this page It's ...
... I'm breast-feeding my newborn and her bowel movements are yellow and mushy. Is this normal for baby poop? Answers from Jay L. Hoecker, M.D. Yellow, mushy bowel movements are perfectly normal for breast-fed babies. Still, ...
Streamlined approach to mapping the magnetic induction of skyrmionic materials
Energy Technology Data Exchange (ETDEWEB)
Chess, Jordan J., E-mail: jchess@uoregon.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States); Montoya, Sergio A. [Center for Memory and Recording Research, University of California, San Diego, CA 92093 (United States); Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Harvey, Tyler R. [Department of Physics, University of Oregon, Eugene, OR 97403 (United States); Ophus, Colin [National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Couture, Simon; Lomakin, Vitaliy; Fullerton, Eric E. [Center for Memory and Recording Research, University of California, San Diego, CA 92093 (United States); Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); McMorran, Benjamin J. [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)
2017-06-15
Highlights: • A method to reconstruction the phase of electrons after pasting though a sample that requires a single defocused image is presented. • Restrictions as to when it is appropriate to apply this method are described. • The relative error associated with this method is compared to conventional transport of intensity equation analysis. - Abstract: Recently, Lorentz transmission electron microscopy (LTEM) has helped researchers advance the emerging field of magnetic skyrmions. These magnetic quasi-particles, composed of topologically non-trivial magnetization textures, have a large potential for application as information carriers in low-power memory and logic devices. LTEM is one of a very few techniques for direct, real-space imaging of magnetic features at the nanoscale. For Fresnel-contrast LTEM, the transport of intensity equation (TIE) is the tool of choice for quantitative reconstruction of the local magnetic induction through the sample thickness. Typically, this analysis requires collection of at least three images. Here, we show that for uniform, thin, magnetic films, which includes many skyrmionic samples, the magnetic induction can be quantitatively determined from a single defocused image using a simplified TIE approach.
Magnus-induced ratchet effects for skyrmions interacting with asymmetric substrates
Reichhardt, C.; Ray, D.; Olson Reichhardt, C. J.
2015-07-01
We show using numerical simulations that pronounced ratchet effects can occur for ac driven skyrmions moving over asymmetric quasi-one-dimensional substrates. We find a new type of ratchet effect called a Magnus-induced transverse ratchet that arises when the ac driving force is applied perpendicular rather than parallel to the asymmetry direction of the substrate. This transverse ratchet effect only occurs when the Magnus term is finite, and the threshold ac amplitude needed to induce it decreases as the Magnus term becomes more prominent. Ratcheting skyrmions follow ordered orbits in which the net displacement parallel to the substrate asymmetry direction is quantized. Skyrmion ratchets represent a new ac current-based method for controlling skyrmion positions and motion for spintronic applications.
Electrical detection of single magnetic skyrmions in metallic multilayers at room temperature
Maccariello, Davide; Legrand, William; Reyren, Nicolas; Garcia, Karin; Bouzehouane, Karim; Collin, Sophie; Cros, Vincent; Fert, Albert
2018-01-01
Magnetic skyrmions are topologically protected whirling spin textures that can be stabilized in magnetic materials by an asymmetric exchange interaction between neighbouring spins that imposes a fixed chirality. Their small size, together with the robustness against external perturbations, make magnetic skyrmions potential storage bits in a novel generation of memory and logic devices. To this aim, their contribution to the electrical transport properties of a device must be characterized—however, the existing demonstrations are limited to low temperatures and mainly in magnetic materials with a B20 crystal structure. Here we combine concomitant magnetic force microscopy and Hall resistivity measurements to demonstrate the electrical detection of sub-100 nm skyrmions in a multilayered thin film at room temperature. Furthermore, we detect and analyse the Hall signal of a single skyrmion, which indicates that it arises from the anomalous Hall effect with a negligible contribution from the topological Hall effect.
Aharonov–Bohm protection of black hole's baryon/skyrmion hair
Directory of Open Access Journals (Sweden)
Gia Dvali
2017-05-01
Full Text Available The baryon/skyrmion correspondence implies that the baryon number is encoded into a topological surface integral. Under certain conditions that we clarify, this surface integral can be measured by an asymptotic observer in form of an Aharonov–Bohm phase-shift in an experiment in which the skyrmion passes through a loop of a probe string. In such a setup the baryon/skyrmion number must be respected by black holes, despite the fact that it produces no long-range classical field. If initially swallowed by a black hole, the baryon number must resurface in form of a classical skyrmion hair, after the black hole evaporates below a certain critical size. Needless to say, the respect of the baryon number by black holes is expected to have potentially-interesting astrophysical consequences.
Aharonov–Bohm protection of black hole's baryon/skyrmion hair
Energy Technology Data Exchange (ETDEWEB)
Dvali, Gia [Arnold-Sommerfeld-Center for Theoretical Physics, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold-Sommerfeld-Center for Theoretical Physics, Ludwig-Maximilians-Universität, 80333 München (Germany)
2017-05-10
The baryon/skyrmion correspondence implies that the baryon number is encoded into a topological surface integral. Under certain conditions that we clarify, this surface integral can be measured by an asymptotic observer in form of an Aharonov–Bohm phase-shift in an experiment in which the skyrmion passes through a loop of a probe string. In such a setup the baryon/skyrmion number must be respected by black holes, despite the fact that it produces no long-range classical field. If initially swallowed by a black hole, the baryon number must resurface in form of a classical skyrmion hair, after the black hole evaporates below a certain critical size. Needless to say, the respect of the baryon number by black holes is expected to have potentially-interesting astrophysical consequences.
Density functional theory study of skyrmion pinning by atomic defects in MnSi
Choi, Hong Chul; Lin, Shi-Zeng; Zhu, Jian-Xin
2016-03-01
A magnetic skyrmion observed experimentally in chiral magnets is a topologically protected spin texture. For their unique properties, such as high mobility under current drive, skyrmions have a huge potential for applications in next-generation spintronic devices. Defects naturally occurring in magnets have profound effects on the static and dynamical properties of skyrmions. In this work we study the effect of an atomic defect on a skyrmion by performing the first-principles calculations within the density functional theory, taking MnSi as an example. By substituting one site of Mn or Si with different elements, we can tune the pinning energy. The effects of pinning by an atomic defect can be understood qualitatively within a phenomenological model.
Spontaneous formation and dynamics of half-skyrmions in a chiral liquid-crystal film
Nych, Andriy; Fukuda, Jun-Ichi; Ognysta, Uliana; Žumer, Slobodan; Muševič, Igor
2017-12-01
Skyrmions are coreless vortex-like excitations emerging in diverse condensed-matter systems, and real-time observation of their dynamics is still challenging. Here we report the first direct optical observation of the spontaneous formation of half-skyrmions. In a thin film of a chiral liquid crystal, depending on experimental conditions including film thickness, they form a hexagonal lattice whose lattice constant is a few hundred nanometres, or appear as isolated entities with topological defects compensating their charge. These half-skyrmions exhibit intriguing dynamical behaviour driven by thermal fluctuations. Numerical calculations of real-space images successfully corroborate the experimental observations despite the challenge because of the characteristic scale of the structures close to the optical resolution limit. A thin film of a chiral liquid crystal thus offers an intriguing platform that facilitates a direct investigation of the dynamics of topological excitations such as half-skyrmions and their manipulation with optical techniques.
Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations
Energy Technology Data Exchange (ETDEWEB)
Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)
2016-12-15
We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.
Ratchet Effects, Negative Mobility, and Phase Locking for Skyrmions on Periodic Substrates
Reichhardt, Charles; Ray, Dipanjan; Olson Reichhardt, Cynthia
We examine the dynamics of skyrmions interacting with 1D and 2D periodic substrates in the presence of dc and ac drives. We find that the Magnus term strongly affects the skyrmion dynamics and that new kinds of phenomena can occur which are absent for overdamped ac and dc driven particles interacting with similar substrates. We show that it is possible to realize a Magnus induced ratchet for skyrmions interacting with an asymmetric potential, where the application of an ac drive can produce quantized dc motion of the skyrmions even when the ac force is perpendicular to the substrate asymmetry direction. For symmetric substrates it is also possible to achieve a negative mobility effect where the net skyrmion motion runs counter to an applied dc drive. Here, as a function of increasing dc drive, the velocity-force curves show a series of locking phases that have different features from the classic Shapiro steps found in overdamped systems. In the phase locking and ratcheting states, the skyrmions undergo intricate 2D orbits induced by the Magnus term.
Skyrmions and Novel Spin Textures in FeGe Thin Films and Artificial B20 Heterostructures
Ahmed, Adam Saied
Skyrmions are magnetic spin textures that have a non-zero topological winding number associated with them. They have attracted much interest recently since they can be as small as 1 nm and could be the next generation of magnetic memory and logic. First, we grow epitaxial films of FeGe by molecular beam epitaxy and characterized the skyrmion properties. This had led us to image skyrmions in real-space with Lorentz transmission electron microscopy for the first time in the United States. Next, from an extensive series of thin and thick films, we have experimentally shown the existence of a magnetic surface state in FeGe and, consequently, any skyrmion material for the first time. Complementary theoretical calculations supported the existence of chiral bobbers--a surface state only predicted in 2015. Next, we fabricated for the first time a new class of skyrmion materials: B20 superlattices. These novel heterostructures of [FeGe/MnGe/CrGe] have now opened the door for tunable skyrmion systems with both Dresselhaus and Rashba Dzyaloshinskii-Moriya interactions. Additionally, we perform resonant soft x-ray scattering to image magnetic spin textures in reciprocal space for FeGe thin films in transmission. We have accomplished the removal of substrate and left an isolated single-crystal FeGe film. Lastly, SrO is grown on graphene as a crystalline, atomically smooth, and pinhole free tunnel barrier for spin injection.
Multidomain Skyrmion Lattice State in Cu2OSeO3.
Zhang, S L; Bauer, A; Burn, D M; Milde, P; Neuber, E; Eng, L M; Berger, H; Pfleiderer, C; van der Laan, G; Hesjedal, T
2016-05-11
Magnetic skyrmions in chiral magnets are nanoscale, topologically protected magnetization swirls that are promising candidates for spintronics memory carriers. Therefore, observing and manipulating the skyrmion state on the surface level of the materials are of great importance for future applications. Here, we report a controlled way of creating a multidomain skyrmion state near the surface of a Cu2OSeO3 single crystal, observed by soft resonant elastic X-ray scattering. This technique is an ideal tool to probe the magnetic order at the L3 edge of 3d metal compounds giving an average depth sensitivity of ∼50 nm. The single-domain 6-fold-symmetric skyrmion lattice can be broken up into domains, overcoming the propagation directions imposed by the cubic anisotropy by applying the magnetic field in directions deviating from the major cubic axes. Our findings open the door to a new way to manipulate and engineer the skyrmion state locally on the surface or on the level of individual skyrmions, which will enable applications in the future.
Full Text Available ... Global Map Premature Birth Report Cards Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & birth Postpartum care Baby ...
... babies younger than 3 months of age. Hib ( Haemophilus influenzae type b) Signs and symptoms can include fever, ... be recommended for travel to certain countries. Hib ( Haemophilus influenzae type b) 3 or 4 2 months, 4 ...
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Laundering Your Baby's Clothes
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Twist1- and Twist2-haploinsufficiency results in reduced bone formation.
Directory of Open Access Journals (Sweden)
Yanyu Huang
Full Text Available Twist1 and Twist2 are highly homologous bHLH transcription factors that exhibit extensive highly overlapping expression profiles during development. While both proteins have been shown to inhibit osteogenesis, only Twist1 haploinsufficiency is associated with the premature synostosis of cranial sutures in mice and humans. On the other hand, biallelic Twist2 deficiency causes only a focal facial dermal dysplasia syndrome or additional cachexia and perinatal lethality in certain mouse strains. It is unclear how these proteins cooperate to synergistically regulate bone formation.Twist1 floxed mice (Twist1(f/f were bred with Twist2-Cre knock-in mice (Twist2(Cre/+ to generate Twist1 and Twist2 haploinsufficient mice (Twist1(f/+; Twist2(Cre/+. X-radiography, micro-CT scans, alcian blue/alizarin red staining, trap staining, BrdU labeling, immunohistochemistry, in situ hybridizations, real-time PCR and dual luciferase assay were employed to investigate the overall skeletal defects and the bone-associated molecular and cellular changes of Twist1(f/+;Twist2(Cre/+ mice.Twist1 and Twist2 haploinsufficient mice did not present with premature ossification and craniosynostosis; instead they displayed reduced bone formation, impaired proliferation and differentiation of osteoprogenitors. These mice exhibited decreased expressions of Fgf2 and Fgfr1-4 in bone, resulting in a down-regulation of FGF signaling. Furthermore, in vitro studies indicated that both Twist1 and Twist2 stimulated 4.9 kb Fgfr2 promoter activity in the presence of E12, a Twist binding partner.These data demonstrated that Twist1- and Twist2-haploinsufficiency caused reduced bone formation due to compromised FGF signaling.
"Oliver Twist": A Teacher's Guide.
Cashion, Carol; Fischer, Diana
This teacher's guide for public television's 3-part adaptation of Charles Dickens's "Oliver Twist" provides information that will help enrich students' viewing of the series, whether or not they read the novel. The guide includes a wide range of discussion and activity ideas; there is also a series Web site and a list of Web resources.…
Waveguides with asymptotically diverging twisting
Czech Academy of Sciences Publication Activity Database
Krejčiřík, David
2015-01-01
Roč. 46, AUG (2015), s. 7-10 ISSN 0893-9659 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : quantum waveguide * exploding twisting * Quasi-bounded * Quasi-cylindrical * discrete spectrum Subject RIV: BE - Theoretical Physics Impact factor: 1.659, year: 2015
Obstructions for twist star products
Bieliavsky, Pierre; Esposito, Chiara; Waldmann, Stefan; Weber, Thomas
2018-05-01
In this short note, we point out that not every star product is induced by a Drinfel'd twist by showing that not every Poisson structure is induced by a classical r-matrix. Examples include the higher genus symplectic Pretzel surfaces and the symplectic sphere S^2.
Twist buckling behavior of arteries.
Garcia, Justin R; Lamm, Shawn D; Han, Hai-Chao
2013-10-01
Arteries are often subjected to torsion due to body movement and surgical procedures. While it is essential that arteries remain stable and patent under twisting loads, the stability of arteries under torsion is poorly understood. The goal of this work was to experimentally investigate the buckling behavior of arteries under torsion and to determine the critical buckling torque, the critical buckling twist angle, and the buckling shape. Porcine common carotid arteries were slowly twisted in vitro until buckling occurred while subjected to a constant axial stretch ratio (1.1, 1.3, 1.5 (in vivo level) and 1.7) and lumen pressure (20, 40, 70 and 100 mmHg). Upon buckling, the arteries snapped to form a kink. For a group of six arteries, the axial stretch ratio significantly affected the critical buckling torque ([Formula: see text]) and the critical buckling twist angle ([Formula: see text]). Lumen pressure also significantly affected the critical buckling torque ([Formula: see text]) but had no significant effect on the critical twist angle ([Formula: see text]). Convex material constants for a Fung strain energy function were determined and fit well with the axial force, lumen pressure, and torque data measured pre-buckling. The material constants are valid for axial stretch ratios, lumen pressures, and rotation angles of 1.3-1.5, 20-100 mmHg, and 0-270[Formula: see text], respectively. The current study elucidates the buckling behavior of arteries under torsion and provides new insight into mechanical instability of blood vessels.
Oishi, Kenichi; Chang, Linda; Huang, Hao
2018-04-03
The baby brain is constantly changing due to its active neurodevelopment, and research into the baby brain is one of the frontiers in neuroscience. To help guide neuroscientists and clinicians in their investigation of this frontier, maps of the baby brain, which contain a priori knowledge about neurodevelopment and anatomy, are essential. "Brain atlas" in this review refers to a 3D-brain image with a set of reference labels, such as a parcellation map, as the anatomical reference that guides the mapping of the brain. Recent advancements in scanners, sequences, and motion control methodologies enable the creation of various types of high-resolution baby brain atlases. What is becoming clear is that one atlas is not sufficient to characterize the existing knowledge about the anatomical variations, disease-related anatomical alterations, and the variations in time-dependent changes. In this review, the types and roles of the human baby brain MRI atlases that are currently available are described and discussed, and future directions in the field of developmental neuroscience and its clinical applications are proposed. The potential use of disease-based atlases to characterize clinically relevant information, such as clinical labels, in addition to conventional anatomical labels, is also discussed. Copyright © 2018. Published by Elsevier Inc.
Noncommutative geometry and twisted conformal symmetry
International Nuclear Information System (INIS)
Matlock, Peter
2005-01-01
The twist-deformed conformal algebra is constructed as a Hopf algebra with twisted coproduct. This allows for the definition of conformal symmetry in a noncommutative background geometry. The twisted coproduct is reviewed for the Poincare algebra and the construction is then extended to the full conformal algebra. The case of Moyal-type noncommutativity of the coordinates is considered. It is demonstrated that conformal invariance need not be viewed as incompatible with noncommutative geometry; the noncommutativity of the coordinates appears as a consequence of the twisting, as has been shown in the literature in the case of the twisted Poincare algebra
Hydrogen bonds and twist in cellulose microfibrils.
Kannam, Sridhar Kumar; Oehme, Daniel P; Doblin, Monika S; Gidley, Michael J; Bacic, Antony; Downton, Matthew T
2017-11-01
There is increasing experimental and computational evidence that cellulose microfibrils can exist in a stable twisted form. In this study, atomistic molecular dynamics (MD) simulations are performed to investigate the importance of intrachain hydrogen bonds on the twist in cellulose microfibrils. We systematically enforce or block the formation of these intrachain hydrogen bonds by either constraining dihedral angles or manipulating charges. For the majority of simulations a consistent right handed twist is observed. The exceptions are two sets of simulations that block the O2-O6' intrachain hydrogen bond, where no consistent twist is observed in multiple independent simulations suggesting that the O2-O6' hydrogen bond can drive twist. However, in a further simulation where exocyclic group rotation is also blocked, right-handed twist still develops suggesting that intrachain hydrogen bonds are not necessary to drive twist in cellulose microfibrils. Copyright © 2017 Elsevier Ltd. All rights reserved.
[Babies with cranial deformity].
Feijen, Michelle M W; Claessens, Edith A W M Habets; Dovens, Anke J Leenders; Vles, Johannes S; van der Hulst, Rene R W J
2009-01-01
Plagiocephaly was diagnosed in a baby aged 4 months and brachycephaly in a baby aged 5 months. Positional or deformational plagio- or brachycephaly is characterized by changes in shape and symmetry of the cranial vault. Treatment options are conservative and may include physiotherapy and helmet therapy. During the last two decades the incidence of positional plagiocephaly has increased in the Netherlands. This increase is due to the recommendation that babies be laid on their backs in order to reduce the risk of sudden infant death syndrome. We suggest the following: in cases of positional preference of the infant, referral to a physiotherapist is indicated. In cases of unacceptable deformity of the cranium at the age 5 months, moulding helmet therapy is a possible treatment option.
Carpenter, Kenneth; Hirsch, Karl F.; Horner, John R.
1996-01-01
In the last couple of decades the study of dinosaur eggs and babies has proved to be one of the most exciting and profitable areas of dinosaur research. This is the first book solely devoted to this topic and reviews, in scientific detail, our present state of knowledge about this exciting area of palaeontology. Chapters in the book discuss all aspects of the science including the occurrence of eggs, nests and baby skeletons, descriptive osteology of juvenile skeletons, comparative histology of juvenile bone, analyses of eggs and egg shells, palaeoenvironments of nesting sites, nesting behaviour and developmental growth of baby dinosaurs. The volume will be an invaluable addition to the book collections of vertebrate palaeontologists and their graduate students.
Baby dumping and evolving baby factories in Nigeria: their ...
African Journals Online (AJOL)
... approach which involves a thorough overhaul of our rigid social orientation which will create room for a conducive environment for child rights and social protection. Keywords: Baby Dumping, Child abandonment, Child Abuse, Child Right, Baby Boxes, Baby Factories, Human Trafficking, Social Protection, Stigma, Nigeria.
Prychynenko, Diana; Sitte, Matthias; Litzius, Kai; Krüger, Benjamin; Bourianoff, George; Kläui, Mathias; Sinova, Jairo; Everschor-Sitte, Karin
2018-01-01
Inspired by the human brain, there is a strong effort to find alternative models of information processing capable of imitating the high energy efficiency of neuromorphic information processing. One possible realization of cognitive computing involves reservoir computing networks. These networks are built out of nonlinear resistive elements which are recursively connected. We propose that a Skyrmion network embedded in magnetic films may provide a suitable physical implementation for reservoir computing applications. The significant key ingredient of such a network is a two-terminal device with nonlinear voltage characteristics originating from magnetoresistive effects, such as the anisotropic magnetoresistance or the recently discovered noncollinear magnetoresistance. The most basic element for a reservoir computing network built from "Skyrmion fabrics" is a single Skyrmion embedded in a ferromagnetic ribbon. In order to pave the way towards reservoir computing systems based on Skyrmion fabrics, we simulate and analyze (i) the current flow through a single magnetic Skyrmion due to the anisotropic magnetoresistive effect and (ii) the combined physics of local pinning and the anisotropic magnetoresistive effect.
Effective potentials for twisted fields
International Nuclear Information System (INIS)
Banach, R.
1981-01-01
Minus the density of the effective action, evaluated at the lowest eigenfunction of the (space-time) derivative part of the second (functional) derivative of the classical action, is proposed as a generalised definition of the effective potential, applicable to twisted as well as untwisted sectors of a field theory. The proposal is corroborated by several specific calculations in the twisted sector, namely phi 4 theory (real and complex) and wrong-sign-Gordon theory, in an Einstein cylinder, where the exact integrability of the static solutions confirms the effective potential predictions. Both models exhibit a phase transition, which the effective potential locates, and the one-loop quantum shift in the critical radius is computed for the real phi 4 model, being a universal result. Topological mass generation at the classical level is pointed out, and the exactness of the classical effective potential approximation for complex phi 4 is discussed. (author)
PKU (Phenylketonuria) in Your Baby
... health conditions > PKU (Phenylketonuria) in your baby PKU (Phenylketonuria) in your baby E-mail to a friend ... this page It's been added to your dashboard . Phenylketonuria (also called PKU) is a condition in which ...
Colostrum: Your Baby's First Meal
... Your Baby's First Meal Ages & Stages Listen Español Text Size Email Print Share Colostrum: Your Baby's First Meal Page Content Article Body Colostrum provides all the nutrients and fluid that your newborn needs in the early days, ...
Twisting formula of epsilon factors
Indian Academy of Sciences (India)
Sazzad Ali Biswas
2017-08-07
Aug 7, 2017 ... In this article, we give a generalized twisting formula for ϵ(χ1χ2,ψ), when both χ1 and χ2 are ramified via the following local Jacobi sums. Let UF be the group of units in OF (ring of integers of F). For characters χ1, χ2 of F. × and a positive integer n, we define the local Jacobi sum. Jt(χ1,χ2, n) = ∑ x∈UF. Un.
Centers for Disease Control (CDC) Podcasts
2017-01-09
Dr. Stacey Bosch, a veterinarian with CDC, discusses her article on Salmonella infections associated with baby turtles. Created: 1/9/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 1/9/2017.
African Journals Online (AJOL)
CASE REPORT. 66. SA JOURNAL OF RADIOLOGY • September 2010. Abstract. We were recently intrigued by a baby born at Kalafong Hospital with fused lower extremities resembling a mermaid, which caused us to search for the background and origin of this entity called sirenomelia. Case report. A 40-year-old woman ...
Full Text Available ... Global Map Premature Birth Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? ... Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth The newborn intensive ...
Full Text Available ... Global Map Premature Birth Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? ... baby Common illnesses Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth The newborn intensive ...
Full Text Available ... mail was sent. Save to my dashboard Sign in or Sign up to save this page. Saving Just a moment, please. You've saved this page It's been added to your dashboard . Time to eat! Feeding your baby helps her grow ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 10. The Blue Baby Syndrome - Nitrate Poisoning in Humans. Deepanjan Majumdar. General Article Volume 8 Issue 10 October 2003 pp 20-30. Fulltext. Click here to view fulltext PDF. Permanent link:
Bachleda, Amelia R.; Thompson, Ross A.
2018-01-01
Babies think differently than adults, and understanding how they think can help us see their explosive brain growth in everyday behavior. Infants learn language faster than adults do, use statistics to understand how the world works, and even reason about the minds of others. But these achievements can be hidden by their poor self-regulatory…
Market analysis baby food Ukraine
A.A. Voronina; I.Z. Dolzhanskiy
2010-01-01
The paper analyzes the development of baby food industry in Ukraine and abroad due the increased level of fertility, unmet needs of baby food products in the growing demand for intervention and strengthening foreign manufacturers. Special attention is paid to government regulation and legislation of the relevant Ukrainian market of baby food.
Boosting Your Baby's Brain Power
Engel-Smothers, Holly; Heim, Susan M.
2009-01-01
With more than 100 billion neurons that would stretch more than 60,000 miles, a newborn baby's brain is quite phenomenal! These neurons must generally form connections within the first eight months of a baby's life to foster optimal brain growth and lifelong learning. Mommies, daddies, and caregivers are extremely vital to ensuring babies reach…
... won't harm your baby. It's common for babies to cry when put down for sleep, but most will quiet themselves if left alone for a few minutes. If the crying lasts longer than a few minutes, check on your baby and offer comforting words. Then give him or ...
Negative baryon density and the folding structure of the B = 3 skyrmion
Foster, D.; Krusch, S.
2013-07-01
The Skyrme model is a nonlinear field theory whose solitonic solutions, once quantized, describe atomic nuclei. The classical static soliton solutions, so-called skyrmions, have interesting symmetries and can only be calculated numerically. Mathematically, these skyrmions can be viewed as maps between two three-manifolds and, as such, their stable singularities can only be folds, cusps and swallowtails. Physically, the occurrence of singularities is related to negative baryon density. In this paper, we calculate the charge three skyrmion to a high resolution in order to examine its singularity structure in detail. Thereby, we explore regions of negative baryon density. We also discuss how the negative baryon density depends on the pion mass.
Negative baryon density and the folding structure of the B = 3 skyrmion
International Nuclear Information System (INIS)
Foster, D; Krusch, S
2013-01-01
The Skyrme model is a nonlinear field theory whose solitonic solutions, once quantized, describe atomic nuclei. The classical static soliton solutions, so-called skyrmions, have interesting symmetries and can only be calculated numerically. Mathematically, these skyrmions can be viewed as maps between two three-manifolds and, as such, their stable singularities can only be folds, cusps and swallowtails. Physically, the occurrence of singularities is related to negative baryon density. In this paper, we calculate the charge three skyrmion to a high resolution in order to examine its singularity structure in detail. Thereby, we explore regions of negative baryon density. We also discuss how the negative baryon density depends on the pion mass. (paper)
Akosa, Collins Ashu
2017-09-09
We demonstrate that the nontrivial magnetic texture of antiferromagnetic skyrmions (AFM-Sks) promotes a non-vanishing topological spin Hall effect (TSHE) on the flowing electrons. This results in a substantial enhancement of the non-adiabatic torque and hence improves the skyrmion mobility. This non-adiabatic torque increases when decreasing the skyrmion size, and therefore scaling down results in a much higher torque efficiency. In clean AFM-Sks, we find a significant boost of the TSHE close to van Hove singularity. Interestingly, this effect is enhanced away from the band gap in the presence of non-magnetic interstitial defects. Furthermore, unlike their ferromagnetic counterpart, TSHE in AFM-Sks increases with increase in disorder strength thus opening promising avenues for materials engineering of this effect.
Modeling and control of active twist aircraft
Cramer, Nicholas Bryan
The Wright Brothers marked the beginning of powered flight in 1903 using an active twist mechanism as their means of controlling roll. As time passed due to advances in other technologies that transformed aviation the active twist mechanism was no longer used. With the recent advances in material science and manufacturability, the possibility of the practical use of active twist technologies has emerged. In this dissertation, the advantages and disadvantages of active twist techniques are investigated through the development of an aeroelastic modeling method intended for informing the designs of such technologies and wind tunnel testing to confirm the capabilities of the active twist technologies and validate the model. Control principles for the enabling structural technologies are also proposed while the potential gains of dynamic, active twist are analyzed.
Field-free deterministic ultrafast creation of magnetic skyrmions by spin-orbit torques
Büttner, Felix; Lemesh, Ivan; Schneider, Michael; Pfau, Bastian; Günther, Christian M.; Hessing, Piet; Geilhufe, Jan; Caretta, Lucas; Engel, Dieter; Krüger, Benjamin; Viefhaus, Jens; Eisebitt, Stefan; Beach, Geoffrey S. D.
2017-11-01
Magnetic skyrmions are stabilized by a combination of external magnetic fields, stray field energies, higher-order exchange interactions and the Dzyaloshinskii-Moriya interaction (DMI). The last favours homochiral skyrmions, whose motion is driven by spin-orbit torques and is deterministic, which makes systems with a large DMI relevant for applications. Asymmetric multilayers of non-magnetic heavy metals with strong spin-orbit interactions and transition-metal ferromagnetic layers provide a large and tunable DMI. Also, the non-magnetic heavy metal layer can inject a vertical spin current with transverse spin polarization into the ferromagnetic layer via the spin Hall effect. This leads to torques that can be used to switch the magnetization completely in out-of-plane magnetized ferromagnetic elements, but the switching is deterministic only in the presence of a symmetry-breaking in-plane field. Although spin-orbit torques led to domain nucleation in continuous films and to stochastic nucleation of skyrmions in magnetic tracks, no practical means to create individual skyrmions controllably in an integrated device design at a selected position has been reported yet. Here we demonstrate that sub-nanosecond spin-orbit torque pulses can generate single skyrmions at custom-defined positions in a magnetic racetrack deterministically using the same current path as used for the shifting operation. The effect of the DMI implies that no external in-plane magnetic fields are needed for this aim. This implementation exploits a defect, such as a constriction in the magnetic track, that can serve as a skyrmion generator. The concept is applicable to any track geometry, including three-dimensional designs.
International Nuclear Information System (INIS)
Zhou, Jinyuan; Xie, Erqing; Sun, Gengzhi; Zhan, Zhaoyao; Zheng, Lianxi
2014-01-01
The dependences of twisting parameters on the electric and mechanical properties of twisted CNT fibers were systematically studied. Results from electric and mechanical measurements showed that twisting intensity is very effective to improve the electric and mechanical properties of CNT fibers. Further calculations combined with Raman results indicate that the twisting treatments, to a certain extent, can greatly enhance the strain transfer factors of the samples, which dominates the mechanical properties of CNT fibers. In addition, studies on the effect of twisting speeds suggested that lower twisting speed can lead to higher uniformity but lower performances in the electric and mechanical properties, higher twisting speed to higher Young’s modulus and higher conductance but lower uniformities. Ultra-strong uniform CNT fibers need to be prepared with a suitable twisting speed. (paper)
Berruto, G.; Madan, I.; Murooka, Y.; Vanacore, G. M.; Pomarico, E.; Rajeswari, J.; Lamb, R.; Huang, P.; Kruchkov, A. J.; Togawa, Y.; LaGrange, T.; McGrouther, D.; Rønnow, H. M.; Carbone, F.
2018-03-01
We demonstrate that light-induced heat pulses of different duration and energy can write Skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz transmission electron microscopy, we directly resolve the spatiotemporal evolution of the magnetization ensuing optical excitation. The Skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-μ s to μ s range, depending on the cooling rate of the system.
International Nuclear Information System (INIS)
Fraerman, A.A.; Ermolaeva, O.L.; Skorohodov, E.V.; Gusev, N.S.; Mironov, V.L.; Vdovichev, S.N.; Demidov, E.S.
2015-01-01
We report the experimental observation of magnetic skyrmion states in patterned ferromagnetic nanostructures consisting of perpendicular magnetized Co/Pt multilayer film exchange coupled with Co nanodisks in vortex state. The magnetic force microscopy and micromagnetic simulations show that depending on the magnitude of Co/Pt perpendicular anisotropy in these systems two different modes of skyrmion formation are realized. - Highlights: • The magnetic force microscopy and micromagnetic simulations of magnetic states in multilayer exchange coupled ferromagnetic nanostructures. • The effects of exchange interaction in Co/Pt multilayer film coupled with Co nanodisks have been studied. • The magnetic scyrmion states at room temperature have been observed
DVCS amplitude with kinematical twist-3 terms
International Nuclear Information System (INIS)
Radyushkin, A.V.; Weiss, C.
2000-01-01
The authors compute the amplitude of deeply virtual Compton scattering (DVCS) using the calculus of QCD string operators in coordinate representation. To restore the electromagnetic gauge invariance (transversality) of the twist-2 amplitude they include the operators of twist-3 which appear as total derivatives of twist-2 operators. The results are equivalent to a Wandzura-Wilczek approximation for twist-3 skewed parton distributions. They find that this approximation gives a finite result for the amplitude of a longitudinally polarized virtual photon, while the amplitude for transverse polarization is divergent, i.e., factorization breaks down in this term
Shaken baby syndrome; Shaken-baby-Syndrom
Energy Technology Data Exchange (ETDEWEB)
Reith, W.; Ahlhelm, F.; Papanagiotou, P. [Universitaetsklinikum des Saarlandes, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Homburg/Saar (Germany); Rohrer, T. [Universitaetsklinikum des Saarlandes, Klinik fuer Allgemeine Paediatrie und Neonatologie, Homburg/Saar (Germany)
2009-10-15
Shaken baby syndrome (SBS) describes the coincidence of subdural hematoma, retinal bleeding and, disadvantageous for the prognosis, diffuse brain damage caused by powerful shaking of the infant. The clinical symptoms include irritability, difficulty with drinking, somnolence, apathy, cerebral cramp attacks, apnoea, temperature regulation disorders and vomiting due to cranial pressure. Milder symptoms of SBS are often not diagnosed and the number of unregistered cases is probably much greater. The diagnosis of SBS is made through the typical symptom constellation, but the lack of retinal bleeding does not exclude the diagnosis. Normally the infants are held by the thorax or upper arms and shaken in a sagittal direction during which the head falls backwards and forwards and is stopped abruptly at each extreme position. The injurious mechanism is considered to be caused by rotational forces which force tissue layers in the brain against each other and also lead to rupture of bridging veins between the skull and the brain. The prognosis is poor and approximately 25% of infants die of SBS within days or weeks. Approximately 75% of survivors suffer from long term damage with physical handicaps, limitations in hearing, visual disturbances up to blindness and mental disorders or combinations of these conditions. Prevention is therefore the most important aspect. (orig.) [German] Das Shaken-baby-Syndrom (SBS) oder Schuetteltrauma des Saeuglings beschreibt die Koinzidenz subduraler Haematome, retinaler Blutungen und prognostisch unguenstiger, diffuser Hirnschaeden durch heftiges Schuetteln eines Saeuglings. Die klinischen Symptome umfassen Irritabilitaet, Trinkschwierigkeiten, Somnolenz, Apathie, zerebrale Krampfanfaelle, Apnoe, Temperaturregulationsstoerungen und Erbrechen durch Hirndruck. Leichtere Symptome des SBS werden haeufig nicht diagnostiziert, die Dunkelziffer ist wahrscheinlich viel hoeher. Die Diagnose des SBS wird durch die typische Symptomkonstellation gestellt
Hou, Zhipeng
2018-01-04
Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confined Fe3Sn2 nanostripe with a width comparable to the featured size of a skyrmion bubble. Systematic investigations on the thermal stability have revealed that the single chain of skyrmion bubbles can keep stable at temperatures varying from RT up to a record-high temperature of 630 K. This extreme stability can be ascribed to the weak temperature-dependent magnetic anisotropy and the formation of edge states at the boundaries of the nanostripes. The realization of the highly stable skyrmion bubble chain in a geometrically confined nanostructure is a very important step toward the application of skyrmion-based spintronic devices.
LAMELLAR ICHTHYOSIS (COLLODION BABY
Directory of Open Access Journals (Sweden)
Paramarta IGE
2012-11-01
Full Text Available The ichthyosis are a heterogeneous group of hereditary and acquired disorder of keratinization which affected the epidermis characterized by presence of visible scales on the skin surface in the absence of inflammation. It can occur as a disease limited to the skin or in association with abnormalities of other organ systems. Lamelar ihthyosis (LI is one of two mayor autosomal recessive ichthyosis with an incidence of approximately one in 300,000. The diagnosis is based on clinical and pathologic finding. Infection is the most common complication, while prognosis of LI is depends on severity and complication of the disease. A case of lamellar ichthyosis in 0 day Balinese female baby was reported. The skin of the body was thick, plate-like appearance, scaling on the entire body, some of the thick skin was ruptured on chest and extremities. There were eclabium on the mouth and ectropion on the eyes. Histopathology examination showed hyperkeratosis without perivascular infiltration lymphocyte. The baby was given breast feeding, antibiotic, hydrocortisone cream and olium olivarum. The prognosis of the baby is good.
Recognition of a Baby's Emotional Cry towards Robotics Baby Caregiver
Directory of Open Access Journals (Sweden)
Shota Yamamoto
2013-02-01
Full Text Available We developed a method for pattern recognition of baby's emotions (discomfortable, hungry, or sleepy expressed in the baby's cries. A 32-dimensional fast Fourier transform is performed for sound form clips, detected by our reported method and used as training data. The power of the sound form judged as a silent region is subtracted from each power of the frequency element. The power of each frequency element after the subtraction is treated as one of the elements of the feature vector. We perform principal component analysis (PCA for the feature vectors of the training data. The emotion of the baby is recognized by the nearest neighbor criterion applied to the feature vector obtained from the test data of sound form clips after projecting the feature vector on the PCA space from the training data. Then, the emotion with the highest frequency among the recognition results for a sound form clip is judged as the emotion expressed by the baby's cry. We successfully applied the proposed method to pattern recognition of baby's emotions. The present investigation concerns the first stage of the development of a robotics baby caregiver that has the ability to detect baby's emotions. In this first stage, we have developed a method for detecting baby's emotions. We expect that the proposed method could be used in robots that can help take care of babies.
Twist-stretch profiles of DNA chains
Zoli, Marco
2017-06-01
Helical molecules change their twist number under the effect of a mechanical load. We study the twist-stretch relation for a set of short DNA molecules modeled by a mesoscopic Hamiltonian. Finite temperature path integral techniques are applied to generate a large ensemble of possible configurations for the base pairs of the sequence. The model also accounts for the bending and twisting fluctuations between adjacent base pairs along the molecules stack. Simulating a broad range of twisting conformation, we compute the helix structural parameters by averaging over the ensemble of base pairs configurations. The method selects, for any applied force, the average twist angle which minimizes the molecule’s free energy. It is found that the chains generally over-twist under an applied stretching and the over-twisting is physically associated to the contraction of the average helix diameter, i.e. to the damping of the base pair fluctuations. Instead, assuming that the maximum amplitude of the bending fluctuations may decrease against the external load, the DNA molecule first over-twists for weak applied forces and then untwists above a characteristic force value. Our results are discussed in relation to available experimental information albeit for kilo-base long molecules.
Large N reduction on a twisted torus
International Nuclear Information System (INIS)
Gonzalez-Arroyo, A.; Narayanan, R.; Neuberger, H.
2005-01-01
We consider SU(N) lattice gauge theory at infinite N defined on a torus with a CP invariant twist. Massless fermions are incorporated in an elegant way, while keeping them quenched. We present some numerical results which suggest that twisting can make numerical simulations of planar QCD more efficient
Energetics Underlying Twist Polymorphisms in Amyloid Fibrils
Periole, Xavier; Huber, Thomas; Bonito-Oliva, Alessandra; Aberg, Karina C; van der Wel, Patrick C A; Sakmar, Thomas P; Marrink, Siewert J
2018-01-01
Amyloid fibrils are highly ordered protein aggregates associated with more than 40 human diseases. The exact conditions in which the fibrils are grown determine many types of reported fibril polymorphism, including different twist patterns. Twist-based polymorphs display unique mechanical properties
Twist buckling of veins under torsional loading.
Garcia, Justin R; Sanyal, Arnav; Fatemifar, Fatemeh; Mottahedi, Mohammad; Han, Hai-Chao
2017-06-14
Veins are often subjected to torsion and twisted veins can hinder and disrupt normal blood flow but their mechanical behavior under torsion is poorly understood. The objective of this study was to investigate the twist deformation and buckling behavior of veins under torsion. Twist buckling tests were performed on porcine internal jugular veins (IJVs) and human great saphenous veins (GSVs) at various axial stretch ratio and lumen pressure conditions to determine their critical buckling torques and critical buckling twist angles. The mechanical behavior under torsion was characterized using a two-fiber strain energy density function and the buckling behavior was then simulated using finite element analysis. Our results demonstrated that twist buckling occurred in all veins under excessive torque characterized by a sudden kink formation. The critical buckling torque increased significantly with increasing lumen pressure for both porcine IJV and human GSV. But lumen pressure and axial stretch had little effect on the critical twist angle. The human GSVs are stiffer than the porcine IJVs. Finite element simulations captured the buckling behavior for individual veins under simultaneous extension, inflation, and torsion with strong correlation between predicted critical buckling torques and experimental data (R 2 =0.96). We conclude that veins can buckle under torsion loading and the lumen pressure significantly affects the critical buckling torque. These results improve our understanding of vein twist behavior and help identify key factors associated in the formation of twisted veins. Copyright © 2017 Elsevier Ltd. All rights reserved.
Dynamics of skyrmions and edge states in the resistive regime of mesoscopic p-wave superconductors
Energy Technology Data Exchange (ETDEWEB)
Fernández Becerra, V., E-mail: VictorLeonardo.FernandezBecerra@uantwerpen.be; Milošević, M.V., E-mail: milorad.milosevic@uantwerpen.be
2017-02-15
Highlights: • Voltage–current characterization of a mesoscopic p-wave superconducting sample. • Skyrmions and edge states are stabilized with an out-of-plane applied magnetic field. • In the resistive regime, moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortices. - Abstract: In a mesoscopic sample of a chiral p-wave superconductor, novel states comprising skyrmions and edge states have been stabilized in out-of-plane applied magnetic field. Using the time-dependent Ginzburg–Landau equations we shed light on the dynamic response of such states to an external applied current. Three different regimes are obtained, namely, the superconducting (stationary), resistive (non-stationary) and normal regime, similarly to conventional s-wave superconductors. However, in the resistive regime and depending on the external current, we found that moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortex, thereby providing new fingerprints for identification of p-wave superconductivity.
Topological dynamics and current-induced motion in a skyrmion lattice
Martinez, J. C.; Jalil, M. B. A.
2016-03-01
We study the Thiele equation for current-induced motion in a skyrmion lattice through two soluble models of the pinning potential. Comprised by a Magnus term, a dissipative term and a pinning force, Thiele’s equation resembles Newton’s law but in virtue of the topological character to the first, it differs significantly from Newtonian mechanics and because the Magnus force is dominant, unlike its mechanical counterpart—the Coriolis force—skyrmion trajectories do not necessarily have mechanical counterparts. This is important if we are to understand skyrmion dynamics and tap into its potential for data-storage technology. We identify a pinning threshold velocity for the one-dimensional pinning potential and for a two-dimensional attractive potential we find a pinning point and the skyrmion trajectories toward that point are spirals whose frequency (compare Kepler’s second law) and amplitude-decay depend only on the Gilbert constant and potential at the pinning point. Other scenarios, e.g. other choices of initial spin velocity, a repulsive potential, etc are also investigated.
Hu, Yong; Chi, Xiaodan; Li, Xuesi; Liu, Yan; Du, An
2017-11-22
In triangular-lattice magnets, the coexistence of third-neighbor antiferromagnetic and nearest-neighbor ferromagnetic exchange interactions can induce rich magnetic phases including noncoplanar skyrmion crystals. Based on Monte Carlo simulation, we studied the dependence of magnetic phase transition on exchange interaction strength. Under the consideration of uniaxial anisotropy and magnetic field both perpendicular to the film plane, a large antiferromagnetic exchange interaction induces a high frustration. When the value of antiferromagnetic exchange interaction is one and a half times larger than the ferromagnetic one, a magnetic phase composed of canting spin stripes, never observed in the chiral magnets, forms. Interestingly, different canting spin stripes along three 120 degree propagation directions may coexist randomly in a magnetic phase, attesting that the canting spin stripes are three-fold degenerate states akin to helices and the multiple state of canting spin stripes is a circular configuration with zero skyrmion charge number. Moreover, skyrmions and antiskyrmions can be observed simultaneously in the configuration at the low temperature nearly close to 0 K, and their configuration and diameter properties are discussed. Finally, the mechanisms of skyrmion creation and annihilation are properly interpreted by comparing exchange and Zeeman energy terms.
Martins, Tiago; de Magalhães, Sérgio Tenreiro
The baby's crying is his most important mean of communication. The crying monitoring performed by devices that have been developed doesn't ensure the complete safety of the child. It is necessary to join, to these technological resources, means of communicating the results to the responsible, which would involve the digital processing of information available from crying. The survey carried out, enabled to understand the level of adoption, in the continental territory of Portugal, of a technology that will be able to do such a digital processing. It was used the TAM as the theoretical referential. The statistical analysis showed that there is a good probability of acceptance of such a system.
Wieser, R
2017-05-04
A self-consistent mean field theory is introduced and used to investigate the thermodynamics and spin dynamics of an S = 1 quantum spin system with a magnetic Skyrmion. The temperature dependence of the Skyrmion profile as well as the phase diagram are calculated. In addition, the spin dynamics of a magnetic Skyrmion is described by solving the time dependent Schrödinger equation with additional damping term. The Skyrmion annihilation process driven by an electric field is used to compare the trajectories of the quantum mechanical simulation with a semi-classical description for the spin expectation values using a differential equation similar to the classical Landau-Lifshitz-Gilbert equation.
Folded supersymmetry with a twist
Energy Technology Data Exchange (ETDEWEB)
Cohen, Timothy [Department of Physics, Princeton University,Princeton, NJ 08544 (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States); Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Lou, Hou Keong [Department of Physics, Princeton University,Princeton, NJ 08544 (United States); Pinner, David [Princeton Center for Theoretical Science, Princeton University,Princeton, NJ 08544 (United States)
2016-03-30
Folded supersymmetry (f-SUSY) stabilizes the weak scale against radiative corrections from the top sector via scalar partners whose gauge quantum numbers differ from their Standard Model counterparts. This non-trivial pairing of states can be realized in extra-dimensional theories with appropriate supersymmetry-breaking boundary conditions. We present a class of calculable f-SUSY models that are parametrized by a non-trivial twist in 5D boundary conditions and can accommodate the observed Higgs mass and couplings. Although the distinctive phenomenology associated with the novel folded states should provide strong evidence for this mechanism, the most stringent constraints are currently placed by conventional supersymmetry searches. These models remain minimally fine-tuned in light of LHC8 data and provide a range of both standard and exotic signatures accessible at LHC13.
Energy Technology Data Exchange (ETDEWEB)
Kolesnikov, A.G. [Laboratory of Thin Film Technologies, School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950 (Russian Federation); Samardak, A.S., E-mail: samardak.as@dvfu.ru [Laboratory of Thin Film Technologies, School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950 (Russian Federation); Stebliy, M.E.; Ognev, A.V.; Chebotkevich, L.A. [Laboratory of Thin Film Technologies, School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950 (Russian Federation); Sadovnikov, A.V.; Nikitov, S.A. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation); Kotel' nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009 (Russian Federation); Kim, Yong Jin; Cha, In Ho [Department of Materials Science and Engineering, Korea University, Seoul 02841 (Korea, Republic of); Kim, Young Keun, E-mail: ykim97@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 02841 (Korea, Republic of)
2017-05-01
One of the major societal challenges is reducing the power consumption of information technology (IT) devices and numerous data centers. Distinct from the current approaches based on switching of magnetic single-domain nanostructures or on movement of domain walls under high currents, an original magnetic skyrmion technology offers ultra-low power, fast, high-density, and scalable spintronic devices, including non-volatile random access memory. Using data-driven micromagnetic simulations, we demonstrate the possibility of spontaneous nucleation and stabilization of different skyrmionic states, such as skyrmions, merons, and meron-like configurations, in heavy metal/ferromagnetic nanodisks with the interfacial Dzyaloshinskii–Moriya interaction (iDMI) as a result of quasi-static magnetization reversal only. Since iDMI is not easily modulated in real systems, we show that skyrmion stabilization is easily achievable by manipulating magnetic anisotropy, saturation magnetization, and the diameters of nanodisks. The state diagrams, presented in terms of the topological charge, allow to explicitly distinguish the intermediate states between skyrmions and merons and can be used for developing a skyrmionic medium, which has been recently proposed to be a building block for future spin-orbitronic devices.
Mruczkiewicz, M.; Gruszecki, P.; Krawczyk, M.; Guslienko, K. Y.
2018-02-01
We study azimuthal spin-wave (SW) excitations in a circular ferromagnetic nanodot in different inhomogeneous, topologically nontrivial magnetization states, specifically, vortex, Bloch-type skyrmion, and Néel-type skyrmion states. A continuous transition between these states is realized by gradually changing the out-of-plane magnetic anisotropy and the Dzyaloshinskii-Moriya exchange interaction (DMI), and the corresponding SW spectra are calculated for each state. We observe the lifting of degeneracy of SW mode frequencies and a change in the systematics of frequency levels. The latter effect is induced by the geometric Berry phase, which occurs in SWs localized at the edge of the dot in the vortex state, and vanishes in the skyrmion states. Furthermore, channeling of edge-localized azimuthal SWs and a related large frequency splitting are observed in the skyrmion states. This is attributed to DMI-induced nonreciprocity, while the coupling of the breathing and gyrotropic modes is related to the skyrmion motion. Finally, we demonstrate efficient coupling of the dynamic magnetization to a uniform magnetic field in nanodots of noncircular symmetry in the skyrmion states.
Protect Yourself and Your Baby from Dengue
... Aedes aegypti mosquitoes • A pregnant woman infected with dengue virus may infect her unborn baby or her newborn baby at birth » Harmful effects of dengue virus infection include death of the unborn baby, low ...
Having a Baby (Especially for Teens)
... Patients About ACOG Having a Baby (Especially for Teens) Home For Patients Search FAQs Having a Baby ( ... 2015 PDF Format Having a Baby (Especially for Teens) Especially For Teens What is prenatal care? What ...
Mefodiev, A. V.; Kudenko, Yu. G.; Mineev, O. V.; Khotjantsev, A. N.
2017-11-01
The main objective of the Baby-MIND detector (Magnetized Iron Neutrino Detector) is the study of muon charge identification efficiency for muon momenta from 0.3 to 5 GeV/ c. This paper presents the results of measurement of the Baby-MIND parameters.
Your Premature Baby: Low Birthweight
... placenta grows in your uterus and supplies your baby with food and oxygen through the umbilical cord. Some problems ... about what you can do to help your baby be healthy. As your child grows, make sure she eats healthy food, stays active and goes to all her health ...
... hot. Use a different spoon to taste your baby’s food. If your baby’s bottle nipple or pacifier falls ... foods like sugar, honey, or syrup. Give Your Baby Healthy Foods m Breast milk is best! Breastfeed your baby ...
Monitoring your baby before labor
... this page: //medlineplus.gov/ency/patientinstructions/000485.htm Monitoring your baby before labor To use the sharing features on ... what the results mean for you and your baby. Alternative Names Prenatal care - monitoring; Pregnancy care - monitoring; Non-stress test - monitoring; NST- ...
Twisted vector bundles on pointed nodal curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Spintronics: A new twist in electronics
Indian Academy of Sciences (India)
BIPUL PAL
Semiconductor Nanostructures. Ultrafast Laser Spectroscopy. Spintronics: A new twist in electronics. Bipul Pal. Indian Institute of Science Education & Research – Kolkata. 02/07/09. 1st Platinum Jubilee Meeting of the Indian Academy of Sciences ...
OAM mode converter in twisted fibers
DEFF Research Database (Denmark)
Usuga Castaneda, Mario A.; Beltran-Mejia, Felipe; Cordeiro, Cristiano
2014-01-01
We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA.......We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA....
Baby swimming and respiratory health.
Nystad, Wenche; Håberg, Siri E; London, Stephanie J; Nafstad, Per; Magnus, Per
2008-05-01
To estimate the effect of baby swimming in the first 6 months of life on respiratory diseases from 6 to 18 months. We used data from The Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health in children born between 1999 and 2005 followed from birth to the age of 18 months (n = 30,870). Health outcomes: lower respiratory tract infections (LRTI), wheeze and otitis media between 6 and 18 months of age. baby swimming at the age of 6 months. The effect of baby swimming was estimated by logistic regression analysis adjusting for potential confounders. About 25% of the children participated in baby swimming. The prevalence of LRTI was 13.3%, wheeze 40.0% and otitis media 30.4%. Children who were baby swimming were not more likely to have LRTI, to wheeze or to have otitis media. However, children with atopic mothers who attended baby swimming had an increased risk of wheeze, adjusted odds ratios (aOR) 1.24 (95% CI 1.11, 1.39), but not LRTI or otitis media. This was also the case for children without respiratory diseases before 6 months aOR 1.08 (95%CI 1.02-1.15). Baby swimming may be related to later wheeze. However, these findings warrant further investigation.
Recognition of a Baby's Emotional Cry Towards Robotics Baby Caregiver
Yamamoto, Shota; Yoshitomi, Yasunari; Tabuse, Masayoshi; Kushida, Kou; Asada, Taro
2013-01-01
We developed a method for pattern recognition of baby's emotions (discomfortable, hungry, or sleepy) expressed in the baby's cries. A 32-dimensional fast Fourier transform is performed for sound form clips, detected by our reported method and used as training data. The power of the sound form judged as a silent region is subtracted from each power of the frequency element. The power of each frequency element after the subtraction is treated as one of the elements of the feature vector. We per...
Ultrafast generation of skyrmionic defects with vortex beams: Printing laser profiles on magnets
Fujita, Hiroyuki; Sato, Masahiro
2017-02-01
Controlling electric and magnetic properties of matter by laser beams is actively explored in the broad region of condensed matter physics, including spintronics and magneto-optics. Here we theoretically propose an application of optical and electron vortex beams carrying intrinsic orbital angular momentum to chiral ferro- and antiferromagnets. We analyze the time evolution of spins in chiral magnets under irradiation of vortex beams by using the stochastic Landau-Lifshitz-Gilbert equation. We show that beam-driven nonuniform temperature leads to a class of ring-shaped magnetic defects, what we call skyrmion multiplex, as well as conventional skyrmions. We discuss the proper beam parameters and the optimal way of applying the beams for the creation of these topological defects. Our findings provide an ultrafast scheme of generating topological magnetic defects in a way applicable to both metallic and insulating chiral (anti-) ferromagnets.
Skyrmion dynamics in a chiral magnet driven by periodically varying spin currents*
Zhu, Rui; Zhang, Yin-Yan
2016-12-01
In this work, we investigated the spin dynamics in a slab of chiral magnets induced by an alternating (ac) spin current. Periodic trajectories of the skyrmion in real space are discovered under the ac current as a result of the Magnus and viscous forces, which originate from the Gilbert damping, the spin transfer torque, and the β-nonadiabatic torque effects. The results are obtained by numerically solving the Landau-Lifshitz-Gilbert equation and can be explained by the Thiele equation characterizing the skyrmion core motion. Supplementary material in the form of one avi file available from the Journal web page at: http://dx.doi.org/10.1140/epjb/e2016-70467-9
Heise, L
1988-01-01
China's birthrate increased from 18 births/1000 population in 1985 to 21/1000 in 1986, after a decade of steady decline. In 1971, to avoid a projected population of 2.4 billion by 2050, Chinese leaders launched the "later-longer-fewer" campaign. Men and women were encouraged to postpone marriage until their mid- to late-20s, to allow 4 years between pregnancies, and to limit their families to 2 children. The standards were slightly more lenient in the rural areas. Together, the campaign was responsible for a reduction in the total fertility rate from 5.9 births/woman in 1970 to 2.7 births in 1979. Yet, due to the age structure of the population, with 39% of Chinese under age 15, even replacement-level fertility was bound to generate growth for decades. Consequently, in 1979, the post-Mao leadership inaugurated the "1-child" policy, a program designed to limit the Chinese population to 1.2 billion by 2000. Family planning has become a state sanctioned and monitored activity. The policy is implemented via public education, persuasion, peer pressure, and a series of incentives and penalties. In this context, the question arises as to what caused China's birthrate to rise. A major factor is the effect of the country's youth-dominated age structure. Following the Great Leap Forward (1958-60) and the prolonged accompanying famine, the birthrate increased markedly as couples conceived the children they had postponed. These baby boomers, born from 1962-64, now are having their own babies. About 1/3 of the 1986 increase in births may be accounted for by the ripple effect of this relatively large cohort finally reaching reproductive age. Further, the age of 1st reproduction has declined recently in response to the Marriage Law of 1980, which lowers the legal marriage age. Another influence has been a gradual yet significant relaxation in some of the basic tenets of the 1-child policy. In 1984, the government reaffirmed the critical importance of family planning but increased
Theory of high-resolution tunneling spin transport on a magnetic skyrmion
Palotás, Krisztián; Rózsa, Levente; Szunyogh, László
2018-01-01
Tunneling spin transport characteristics of a magnetic skyrmion are described theoretically in magnetic scanning tunneling microscopy (STM). The spin-polarized charge current in STM (SP-STM) and tunneling spin transport vector quantities, the longitudinal spin current and the spin transfer torque are calculated in high spatial resolution within the same theoretical framework. A connection between the conventional charge current SP-STM image contrasts and the magnitudes of the spin transport v...
Collodion Baby - a Case Report
Directory of Open Access Journals (Sweden)
Stojanović Vesna
2014-12-01
Full Text Available Colloidon baby describes a highly characteristic clinical entity in newborns encased in a yellowish translucent membrane resembling collodion. In most cases the condition either precedes the development of one of a variety of ichthyoses, the commonest of which are lamellar ichthyosis and non-bullous ichthyosiform erythroderma, or occasionally represents an initial phase of other ichthyoses such as ichthyosis vulgaris. In at least 10% of all cases of collodion baby, the condition is followed by a mild ichthyosis of lamellar type, so mild as to be considered more or less normal, so-called self-healing collodion baby or ‘lamellar ichthyosis of the newborn’. In this report we present a rare case of collodion baby in whom, after collodion membrane peeled-off, the skin retained normal appearance.
... on a standardized growth chart (there are different charts for boys and girls). Whether your baby is large, small, or medium-sized, as long as this growth pattern stays consistent over time, chances are everything is ...
Baby's Head Shape: What's Normal?
... conservative and helmet therapy for positional cranial deformation. Plastic and Reconstructive Surgery. In press. Accessed Dec. 19, ... infant-and-toddler-health/in-depth/healthy-baby/art-20045964 . Mayo Clinic Footer Legal Conditions and Terms ...
[Manufactured baby food: safety expectations].
Davin, L; Van Egroo, L-D; Galesne, N
2010-12-01
Food safety is a concern for parents of infants, and healthcare professionals are often questioned by them about this topic. Baby food European regulation ensures high levels of safety and is more rigorous than common food regulation. Maximal limit for pesticides in baby food demonstrates the high level of requirements. This limit must be below the 10 ppb detection threshold, whatever the chemical used. Other contaminants such as nitrates are also the subject of greater expectations in baby food. Food safety risks control needs a specific know-how that baby food manufacturers have acquired and experienced, more particularly by working with producers of high quality raw material. Copyright © 2010 Elsevier Masson SAS. All rights reserved.
Positioning your baby for breastfeeding
... knees snug against your body. If your nipple hurts, see if your baby has slipped down and ... Rasmussen KM. Breastfeeding and health outcomes for the mother-infant dyad. Pediatr Clin North Am . 2013;60( ...
Universal current-velocity relation of skyrmion motion in chiral magnets
Iwasaki, Junichi; Mochizuki, Masahito; Nagaosa, Naoto
2013-03-01
Current-driven motion of the magnetic domain wall requires large critical current density jc ~109 -1012 A/m2, at which the joule heating is a serious problem. The skyrmions recently discovered in chiral magnets, on the other hand, have much smaller critical current of jc ~105 -106 A/m2. We present a numerical simulation of the Landau-Lifshitz-Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the slyrmion motion driven by the spin transfer torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix (HL). Simulation results are analyzed using a theory based on Thiele's equation, and it is concluded that this surprising behavior is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal (SkX), which enable them to avoid pinning centers and then weaken the net pinning force. Dynamical deformation of SkX leads to the fluctuation of Bragg peak with large amplitude, which can be detected by the recent neutron-scattering experiment.
International Nuclear Information System (INIS)
Reith, W.; Ahlhelm, F.; Papanagiotou, P.; Rohrer, T.
2009-01-01
Shaken baby syndrome (SBS) describes the coincidence of subdural hematoma, retinal bleeding and, disadvantageous for the prognosis, diffuse brain damage caused by powerful shaking of the infant. The clinical symptoms include irritability, difficulty with drinking, somnolence, apathy, cerebral cramp attacks, apnoea, temperature regulation disorders and vomiting due to cranial pressure. Milder symptoms of SBS are often not diagnosed and the number of unregistered cases is probably much greater. The diagnosis of SBS is made through the typical symptom constellation, but the lack of retinal bleeding does not exclude the diagnosis. Normally the infants are held by the thorax or upper arms and shaken in a sagittal direction during which the head falls backwards and forwards and is stopped abruptly at each extreme position. The injurious mechanism is considered to be caused by rotational forces which force tissue layers in the brain against each other and also lead to rupture of bridging veins between the skull and the brain. The prognosis is poor and approximately 25% of infants die of SBS within days or weeks. Approximately 75% of survivors suffer from long term damage with physical handicaps, limitations in hearing, visual disturbances up to blindness and mental disorders or combinations of these conditions. Prevention is therefore the most important aspect. (orig.) [de
Laëtitia Pedroso
2011-01-01
With the machine restart and first collisions at 3.5 TeV, 2009 and 2010 were two action-packed years at the LHC. The events were a real media success, but one important result that remained well hidden was the ten births in the LHC team over the same period. The mothers – engineers, cryogenics experts and administrative assistants working for the LHC – confirm that it is possible to maintain a reasonable work-life balance. Two of them tell us more… Verena Kain (left) and Reyes Alemany (right) in the CERN Control Centre. With the LHC running around the clock, LHC operations engineers have high-pressure jobs with unsociable working hours. These past two years, which will undoubtedly go down in the annals of CERN history, the LHC team had their work cut out, but despite their high-octane professional lives, several female members of the team took up no less of a challenge in their private lives, creating a mini-baby-boom by which the LHC start-up will also be remembe...
Reichhardt, Charles; Reichhardt, Cynthia J. Olson
We numerically examine skyrmions interacting with a periodic quasi-one-dimensional substrate. When we drive the skyrmions perpendicular to the substrate periodicity direction, a rich variety of nonlinear Magnus-induced effects arise, in contrast to an overdamped system that shows only a linear velocity-force curve for this geometry. The skyrmion velocity-force curve is strongly nonlinear and we observe a Magnus-induced speed-up effect when the pinning causes the Magnus velocity response to align with the dissipative response. At higher applied drives these components decouple, resulting in strong negative differential conductivity. For skyrmions under combined ac and dc driving, we find a new class of phase locking phenomena in which the velocity-force curves contain a series of what we call Shapiro spikes, distinct from the Shapiro steps observed in overdamped systems. There are also regimes in which the skyrmion moves in the direction opposite to the applied dc drive to give negative mobility.
Hou, Zhipeng
2017-06-07
The quest for materials hosting topologically protected skyrmionic spin textures continues to be fueled by the promise of novel devices. Although many materials have demonstrated the existence of such spin textures, major challenges remain to be addressed before devices based on magnetic skyrmions can be realized. For example, being able to create and manipulate skyrmionic spin textures at room temperature is of great importance for further technological applications because they can adapt to various external stimuli acting as information carriers in spintronic devices. Here, the first observation of skyrmionic magnetic bubbles with variable topological spin textures formed at room temperature in a frustrated kagome Fe3 Sn2 magnet with uniaxial magnetic anisotropy is reported. The magnetization dynamics are investigated using in situ Lorentz transmission electron microscopy, revealing that the transformation between different magnetic bubbles and domains is via the motion of Bloch lines driven by an applied external magnetic field. These results demonstrate that Fe3 Sn2 facilitates a unique magnetic control of topological spin textures at room temperature, making it a promising candidate for further skyrmion-based spintronic devices.
Towards control of the size and helicity of skyrmions in helimagnetic alloys by spin-orbit coupling
Shibata, K.; Yu, X. Z.; Hara, T.; Morikawa, D.; Kanazawa, N.; Kimoto, K.; Ishiwata, S.; Matsui, Y.; Tokura, Y.
2013-10-01
Chirality--that is, left- or right-handedness--is an important concept in a broad range of scientific areas. In condensed matter, chirality is found not only in molecular or crystal forms, but also in magnetic structures. A magnetic skyrmion is a topologically stable spin vortex structure, as observed in chiral-lattice helimagnets, and is one example of such a structure. The spin swirling direction (skyrmion helicity) should be closely related to the underlying lattice chirality via the relativistic spin-orbit coupling. Here, we report on the correlation between skyrmion helicity and crystal chirality in alloys of helimagnets Mn1-xFexGe with varying compositions by Lorentz transmission electron microscopy and convergent-beam electron diffraction over a broad range of compositions (x = 0.3-1.0). The skyrmion lattice constant shows non-monotonous variation with composition x, with a divergent behaviour around x = 0.8, where the correlation between magnetic helicity and crystal chirality changes sign. This originates from continuous variation of the spin-orbit coupling strength and its sign reversal in the metallic alloys as a function of x. Controllable spin-orbit coupling may offer a promising way to tune skyrmion size and helicity.
Mesoscale mechanics of twisting carbon nanotube yarns.
Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J
2015-03-12
Fabricating continuous macroscopic carbon nanotube (CNT) yarns with mechanical properties close to individual CNTs remains a major challenge. Spinning CNT fibers and ribbons for enhancing the weak interactions between the nanotubes is a simple and efficient method for fabricating high-strength and tough continuous yarns. Here we investigate the mesoscale mechanics of twisting CNT yarns using full atomistic and coarse grained molecular dynamics simulations, considering concurrent mechanisms at multiple length-scales. To investigate the mechanical response of such a complex structure without losing insights into the molecular mechanism, we applied a multiscale strategy. The full atomistic results are used for training a coarse grained model for studying larger systems consisting of several CNTs. The mesoscopic model parameters are updated as a function of the twist angle, based on the full atomistic results, in order to incorporate the atomistic scale deformation mechanisms in larger scale simulations. By bridging across two length scales, our model is capable of accurately predicting the mechanical behavior of twisted yarns while the atomistic level deformations in individual nanotubes are integrated into the model by updating the parameters. Our results focused on studying a bundle of close packed nanotubes provide novel mechanistic insights into the spinning of CNTs. Our simulations reveal how twisting a bundle of CNTs improves the shear interaction between the nanotubes up to a certain level due to increasing the interaction surface. Furthermore, twisting the bundle weakens the intertube interactions due to excessive deformation in the cross sections of individual CNTs in the bundle.
TWIST is Expressed in Human Gliomas, Promotes Invasion
Directory of Open Access Journals (Sweden)
Maria C. Elias
2005-09-01
Full Text Available TWIST is a basic helix-loop-helix (bHLH transcription factor that regulates mesodermal development, promotes tumor cell metastasis, and, in response to cytotoxic stress, enhances cell survival. Our screen for bHLH gene expression in rat C6 glioma revealed TWIST. To delineate a possible oncogenic role for TWIST in the human central nervous system (CNS, we analyzed TWIST message, protein expression in gliomas, normal brain. TWIST was detected in the large majority of human glioma-derived cell lines, human gliomas examined. Increased TWIST mRNA levels were associated with the highest grade gliomas, increased TWIST expression accompanied transition from low grade to high grade in vivo, suggesting a role for TWIST in promoting malignant progression. In accord, elevated TWIST mRNA abundance preceded the spontaneous malignant transformation of cultured mouse astrocytes hemizygous for p53. Overexpression of TWIST protein in a human glioma cell line significantly enhanced tumor cell invasion, a hallmark of high-grade gliomas. These findings support roles for TWIST both in early glial tumorigenesis, subsequent malignant progression. TWIST was also expressed in embryonic, fetal human brain, in neurons, but not glia, of mature brain, indicating that, in gliomas, TWIST may promote the functions also critical for CNS development or normal neuronal physiology.
Analysis of gun barrel rifling twist
Sun, Jia; Chen, Guangsong; Qian, Linfang; Liu, Taisu
2017-05-01
Aiming at the problem of gun barrel rifling twist, the constraint relation between rifling and projectile is investigated. The constraint model of rifling and projectile is established and the geometric relation between the twist and the motion of projectile is analyzed. Based on the constraint model, according to the rotating band that is fired, the stress and the motion law of the rotating band in bore are analyzed. The effects to rotating band (double rotating band or wide driving band) caused by different rifling (rib rifling, increasing rifling and combined rifling) are also investigated. The model is demonstrated by several examples. The results of numerical examples and the constraint mode show that the uncertainty factors will be brought in the increasing rifling and combined rifling during the projectile move in the bore. According to the amplitude and the strength of the twist acting on rotating band, the steady property of rotational motion of the projectile, the rib rifling is a better choose.
Electrically Controllable Magnetism in Twisted Bilayer Graphene.
Gonzalez-Arraga, Luis A; Lado, J L; Guinea, Francisco; San-Jose, Pablo
2017-09-08
Twisted graphene bilayers develop highly localized states around AA-stacked regions for small twist angles. We show that interaction effects may induce either an antiferromagnetic or a ferromagnetic (FM) polarization of said regions, depending on the electrical bias between layers. Remarkably, FM-polarized AA regions under bias develop spiral magnetic ordering, with a relative 120° misalignment between neighboring regions due to a frustrated antiferromagnetic exchange. This remarkable spiral magnetism emerges naturally without the need of spin-orbit coupling, and competes with the more conventional lattice-antiferromagnetic instability, which interestingly develops at smaller bias under weaker interactions than in monolayer graphene, due to Fermi velocity suppression. This rich and electrically controllable magnetism could turn twisted bilayer graphene into an ideal system to study frustrated magnetism in two dimensions.
Quantum entanglement of baby universes
International Nuclear Information System (INIS)
Aganagic, Mina; Okuda, Takuya; Ooguri, Hirosi
2007-01-01
We study quantum entanglements of baby universes which appear in non-perturbative corrections to the OSV formula for the entropy of extremal black holes in type IIA string theory compactified on the local Calabi-Yau manifold defined as a rank 2 vector bundle over an arbitrary genus G Riemann surface. This generalizes the result for G=1 in hep-th/0504221. Non-perturbative terms can be organized into a sum over contributions from baby universes, and the total wave-function is their coherent superposition in the third quantized Hilbert space. We find that half of the universes preserve one set of supercharges while the other half preserve a different set, making the total universe stable but non-BPS. The parent universe generates baby universes by brane/anti-brane pair creation, and baby universes are correlated by conservation of non-normalizable D-brane charges under the process. There are no other source of entanglement of baby universes, and all possible states are superposed with the equal weight
On the Symmetric Properties for the Generalized Twisted Bernoulli Polynomials
Directory of Open Access Journals (Sweden)
Kim Taekyun
2009-01-01
Full Text Available We study the symmetry for the generalized twisted Bernoulli polynomials and numbers. We give some interesting identities of the power sums and the generalized twisted Bernoulli polynomials using the symmetric properties for the -adic invariant integral.
Baby-Boom, Baby-Bust and the Great Depression
Andriana BELLOU; Emanuela CARDIA
2015-01-01
The baby-boom and subsequent baby-bust have shaped much of the history of the second half of the 20th century; yet it is still largely unclear what caused them. This paper presents a new unified explanation of the fertility Boom-Bust that links the latter to the Great Depression and the subsequent economic recovery. We show that the 1929 Crash attracted young married women 20 to 34 years old in 1930 (whom we name D-cohort) in the labor market possibly via an added worker effect. Using several...
Evans, M
2001-02-01
Though many objections can be levelled against the idea of the practice of genetic intervention to produce 'designer babies', upon examination they are shown to hinge on features which concern parental intentions towards their children, rather than features specific to the means involved. These intentions may be pursued by a variety of social practices which may, though need not, involve a measure of 'traditional' genetic selection (i.e. in terms of the identity and characteristics of the reproducing partners). This paper reviews a number of these objections and, by parity of reasoning, rejects their claim to count specifically or decisively against genetic intervention in pursuit of 'designer babies'. Rejecting these objections does not lead to the endorsement of 'designing babies, but it shows that any unease must be grounded elsewhere and defended by other arguments.
Twisted surfaces in the Pseudo-Galilean space
Directory of Open Access Journals (Sweden)
Ahmet Kazan
2017-10-01
Full Text Available In this paper, we construct the twisted surfaces according to the supporting plane and type of rotations in pseudo-Galilean space G13. Also, we find the Gaussian curvatures and mean curvatures of the different types of these twisted surfaces and draw some figures for these twisted surfaces.
Baby MIND Experiment Construction Status
Energy Technology Data Exchange (ETDEWEB)
Antonova, M.; et al.
2017-04-28
Baby MIND is a magnetized iron neutrino detector, with novel design features, and is planned to serve as a downstream magnetized muon spectrometer for the WAGASCI experiment on the T2K neutrino beam line in Japan. One of the main goals of this experiment is to reduce systematic uncertainties relevant to CP-violation searches, by measuring the neutrino contamination in the anti-neutrino beam mode of T2K. Baby MIND is currently being constructed at CERN, and is planned to be operational in Japan in October 2017.
Hilbert's Grand Hotel with a series twist
Wijeratne, Chanakya; Mamolo, Ami; Zazkis, Rina
2014-08-01
This paper presents a new twist on a familiar paradox, linking seemingly disparate ideas under one roof. Hilbert's Grand Hotel, a paradox which addresses infinite set comparisons is adapted and extended to incorporate ideas from calculus - namely infinite series. We present and resolve several variations, and invite the reader to explore his or her own variations.
Hardy Inequalities in Globally Twisted Waveguides
Czech Academy of Sciences Publication Activity Database
Briet, Ph.; Hammedi, H.; Krejčiřík, David
2015-01-01
Roč. 105, č. 7 (2015), s. 939-958 ISSN 0377-9017 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : quantum waveguides * twisted tubes * Dirichlet Laplacian * Hardy inequality Subject RIV: BE - Theoretical Physics Impact factor: 1.517, year: 2015
DeMarco, Frederick
2010-01-01
This article describes an art activity on self-portraiture inspired by artist Tim Hawkinson. Hawkinson created a sculpture titled "Emoter" in which his face, moved by motors, twisted and contorted based on random signals from a TV. This art activity incorporates technology into the art room, brings the work of practicing artists alive, and is a…
Twisted holomorphic forms on generalized flag varieties
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
As a corollary of Theorem 1 and Proposition 2, we get the following vanishing theorem: ..... easily what the maximum positive value is which can occur in (µ, α∨ ... Twisted holomorphic forms on generalized flag varieties. 129. The following observation will be useful in writing down the conditions stated in the proposition.
Twisted Frobenius Identities from Vertex Operator Superalgebras
Directory of Open Access Journals (Sweden)
Alexander Zuevsky
2017-01-01
Full Text Available In consideration of the continuous orbifold partition function and a generating function for all n-point correlation functions for the rank two free fermion vertex operator superalgebra on the self-sewing torus, we introduce the twisted version of Frobenius identity.
Magnetization Modeling of Twisted Superconducting Filaments
Satiramatekul, T; Devred, Arnaud; Leroy, Daniel
2007-01-01
This paper presents a new Finite Element numerical method to analyze the coupling between twisted filaments in a superconducting multifilament composite wire. To avoid the large number of elements required by a 3D code, the proposed method makes use of the energy balance principle in a 2D code. The relationship between superconductor critical current density and local magnetic flux density is implemented in the program for the Bean and modified Kim models. The modeled wire is made up of six filaments twisted together and embedded in a lowresistivity matrix. Computations of magnetization cycle and of the electric field pattern have been performed for various twist pitch values in the case of a pure copper matrix. The results confirm that the maximum magnetization depends on the matrix conductivity, the superconductor critical current density, the applied field frequency, and the filament twist pitch. The simulations also lead to a practical criterion for wire design that can be used to assess whether or not th...
Akachan ni Kanpai! Celebrating the baby: Baby, family, culture.
Watanabe, Hisako
2011-01-01
"Akachan ni Kanpai! Celebrating the Baby: Baby, Family, Culture" was the theme of the 11th World Congress of the World Association for Infant Mental Health (August 2008). It denotes every baby's right to be blessed from the beginning of life, whether the baby is healthy, ill, disabled, or born into unwelcoming social contexts. Across the world, modern families of the 21st century face increasingly stressful lives. Japan, with a rapid postwar social change, has yielded increasing cases of postnatal depression and abuse, alerting her to reevaluate amae, a cultural affinity for interdependency. Amae, as studied by Takeo Doi, originates in the mother--infant relationship and is carried through into adulthood characterizing Japanese mentality. The Japanese values for things simple, small, slow, and silent are typical in the art of haiku and Noh, but also render significant in infant mental health. Infants born under impossible conditions, such as those born extremely small and with congenital anomalies, survive through simple, sincere, sensitive care imbued with respect to their subtle signs. Their narratives of slow and steady progress from despair to a loving family context urge us to say "Akachan ni Kanpai" to countless infants worldwide whose voices are yet to be heard. Copyright © 2011 Michigan Association for Infant Mental Health.
29 BABY DUMPING AND EVOLVING BABY FACTORIES IN NIGERIA
African Journals Online (AJOL)
various purposes ranging from illegal international and domestic adoptions, rituals, slave labour or sexual exploitation (Huntley, 2013). This implies that more than economic factors (poverty), the social stigma which their condition carries is a more propelling factor influencing their resort to baby factories which supposedly ...
Morphing wing structure with controllable twist based on adaptive bending-twist coupling
Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo
2013-06-01
A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.
Morphing wing structure with controllable twist based on adaptive bending–twist coupling
International Nuclear Information System (INIS)
Raither, Wolfram; Heymanns, Matthias; Ermanni, Paolo; Bergamini, Andrea
2013-01-01
A novel semi-passive morphing airfoil concept based on variable bending–twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated. (paper)
Breastfeeding FAQs: Sleep - Yours and Your Baby's
... Staying Safe Videos for Educators Search English Español Breastfeeding FAQs: Sleep - Yours and Your Baby's KidsHealth / For Parents / Breastfeeding FAQs: Sleep - Yours and Your Baby's What's in ...
Sick Baby? When to Seek Medical Attention
Healthy Lifestyle Infant and toddler health When a healthy baby gets sick, don't panic. Understand when to ... 20, 2016 Original article: http://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/in-depth/healthy-baby/ ...
Will Stress during Pregnancy Affect My Baby?
... baby? Share Facebook Twitter Pinterest Email Print Will stress during pregnancy affect my baby? It is normal ... care provider during your prenatal visits. Post-Traumatic Stress Disorder (PTSD) and Pregnancy PTSD is a more ...
When Your Baby Has a Birth Defect
... Search English Español When Your Baby Has a Birth Defect KidsHealth / For Parents / When Your Baby Has ... to help you and your child. What Are Birth Defects? Birth defects (also called congenital anomalies) are ...
Fetal Echocardiography/Your Unborn Baby's Heart
... Artery Disease Venous Thromboembolism Aortic Aneurysm More Fetal Echocardiography / Your Unborn Baby's Heart Updated:Oct 6,2016 ... Your Risk • Symptoms & Diagnosis Introduction Common Tests Fetal Echocardiography/Your Unborn Baby's Heart - Fetal Echocardiogram Test - Detection ...
Density-waves instability and a skyrmion lattice on the surface of strong topological insulators
Baum, Yuval; Stern, Ady
2012-11-01
In this work we analyze the instability conditions for spin-density-wave (SDW) formation on the surface of strong topological insulators. We find that for a certain range of Fermi energies and strength of interactions the SDW state is favored compared to the unmagnetized and the uniform-magnetization states. We also find that the SDWs are of spiral nature and, for a certain range of parameters, a Skyrmion lattice may form on the surface. We show that this phase may have a nontrivial Chern number even in the absence of an external magnetic field.
Anisotropic magnetocrystalline coupling of the skyrmion lattice in MnSi
Luo, Yongkang; Lin, Shi-Zeng; Fobes, D. M.; Liu, Zhiqi; Bauer, E. D.; Betts, J. B.; Migliori, A.; Thompson, J. D.; Janoschek, M.; Maiorov, B.
2018-03-01
We investigate the anisotropic nature of magnetocrystalline coupling between the crystallographic and skyrmion crystal (SKX) lattices in the chiral magnet MnSi by magnetic field-angle resolved resonant ultrasound spectroscopy. Abrupt changes are observed in the elastic moduli and attenuation when the magnetic field is parallel to the [011] crystallographic direction. These observations are interpreted in a phenomenological Ginzburg-Landau theory that identifies switching of the SKX orientation to be the result of an anisotropic magnetocrystalline coupling potential. Our paper sheds new light on the nature of magnetocrystalline coupling potential relevant to future spintronic applications.
... concerned your baby has slowed growth or a drop in weight, the doctor may ask these questions: Has your ... Crawling, cruising, and walking will burn calories, so weight gain might not be as ... the spoon on the floor than eating? The world is a fascinating place, ...
Babies, Toddlers and the Media.
Fenichel, Emily, Ed.
2001-01-01
"Zero to Three" is a single-focus bulletin of the National Center for Infants, Toddlers, and Families providing insight from multiple disciplines on the development of infants, toddlers, and their families. Noting that America's babies and toddlers live in a world full of television sets, VCRs, computers, videogames, and interactive…
Feeding patterns and diet -- babies and infants
... time digesting cow's milk. Do not feed your baby any solid food until 4 to 6 months old. Your baby ... away or by not opening their mouth. Your baby begins showing interest in food when others are eating. When to Call the ...
Collodion baby: A report of 4 cases
African Journals Online (AJOL)
owner
2012-12-28
Dec 28, 2012 ... decent. The abnormal appearances of the babies' skin were all no- ticed at birth. ... mal appearance of the baby's skin was noticed at birth. Baby was delivered at home but mother presented im- .... autosomal recessive fashion.16 Placental insufficiency and post maturity have also been implicated in some.
A novel role for Twist-1 in pulp homeostasis.
Galler, K M; Yasue, A; Cavender, A C; Bialek, P; Karsenty, G; D'Souza, R N
2007-10-01
The molecular mechanisms that maintain the equilibrium of odontoblast progenitor cells in dental pulp are unknown. Here we tested whether homeostasis in dental pulp is modulated by Twist-1, a nuclear protein that partners with Runx2 during osteoblast differentiation. Our analysis of Twist-1(+/-) mice revealed phenotypic changes that involved an earlier onset of dentin matrix formation, increased alkaline phosphatase activity, and pulp stones within the pulp. RT-PCR analyses revealed Twist-1 expression in several adult organs, including pulp. Decreased levels of Twist-1 led to higher levels of type I collagen and Dspp gene expression in perivascular cells associated with the pulp stones. In mice heterozygous for both Twist-1 and Runx2 inactivation, the phenotype of pulp stones appeared completely rescued. These findings suggest that Twist-1 plays a key role in restraining odontoblast differentiation, thus maintaining homeostasis in dental pulp. Furthermore, Twist-1 functions in dental pulp are dependent on its interaction with Runx2.
HREM of general and twist grain boundaries.
Energy Technology Data Exchange (ETDEWEB)
Merkle, K. L.; Thompson, L. J.
1999-03-10
The observation of atomic-scale structures of grain boundaries (GBs) via axial illumination HREM has been largely restricted to tilt GBs, due to the requirement that the electron beam be parallel to a low-index zone axis on both sides of the interface. This condition can be fulfilled for all tilt GBs with disorientation about a low-index direction. The information obtained through HREM studies in many materials has brought important insights concerning the atomic-scale structure of such boundaries. However, it is well known that tilt GBs occupy only an infinitesimally small fraction of the 5-dimensional phase space which describes the macroscopic geometry of all GBs. Therefore, although tilt GBs are very important due to their low energy, it would be useful to also study twist GBs and general GBs that contain twist and tilt components.
IRONY IN CHARLES DICKEN'S OLIVER TWIST
Directory of Open Access Journals (Sweden)
Ika Kana Trisnawati
2016-05-01
Full Text Available This paper describes the types of irony used by Charles Dickens in his notable early work, Oliver Twist, as well as the reasons the irony was chosen. As a figurative language, irony is utilized to express one’s complex feelings without truly saying them. In Oliver Twist, Dickens brought the readers some real social issues wrapped in dark, deep written expressions of irony uttered by the characters of his novel. Undoubtedly, the novel had left an impact to the British society at the time. The irony Dickens displayed here includes verbal, situational, and dramatic irony. His choice of irony made sense as he intended to criticize the English Poor Laws and to touch the public sentiment. He wanted to let the readers go beyond what was literally written and once they discovered what the truth was, they would eventually understand Dickens’ purposes.
Leibniz algebroids, twistings and exceptional generalized geometry
Baraglia, D.
2012-05-01
We investigate a class of Leibniz algebroids which are invariant under diffeomorphisms and symmetries involving collections of closed forms. Under appropriate assumptions we arrive at a classification which in particular gives a construction starting from graded Lie algebras. In this case the Leibniz bracket is a derived bracket and there are higher derived brackets resulting in an L∞-structure. The algebroids can be twisted by a non-abelian cohomology class and we prove that the twisting class is described by a Maurer-Cartan equation. For compact manifolds we construct a Kuranishi moduli space of this equation which is shown to be affine algebraic. We explain how these results are related to exceptional generalized geometry.
MAGNETIC FIELD TWISTING BY INTERGRANULAR DOWNDRAFTS
Energy Technology Data Exchange (ETDEWEB)
Taroyan, Youra; Williams, Thomas [Department of Physics, IMPACS, Aberystwyth University, Aberystwyth (United Kingdom)
2016-10-01
The interaction of an intergranular downdraft with an embedded vertical magnetic field is examined. It is demonstrated that the downdraft may couple to small magnetic twists leading to an instability. The descending plasma exponentially amplifies the magnetic twists when it decelerates with depth due to increasing density. Most efficient amplification is found in the vicinity of the level, where the kinetic energy density of the downdraft reaches equipartition with the magnetic energy density. Continual extraction of energy from the decelerating plasma and growth in the total azimuthal energy occurs as a consequence of the wave-flow coupling along the downdraft. The presented mechanism may drive vortices and torsional motions that have been detected between granules and in simulations of magnetoconvection.
["Designer baby" changed to French for "double hope baby"].
Fagniez, P-L; Loriau, J; Tayar, C
2005-10-01
Scientific advances during the last decades regarding potential intervention on embryos arouse many questions in society to prepare the ground concerning the limits that should be set for these practices. For the first time in 1994, a parliamentary proceeding allowed the definition of a French model of bioethics through laws of the same name. These laws, among others, authorized in a well and strictly defined setting the practice of preimplantation genetic diagnosis (PGD). Because of technical progress concerning PGD, new questions arose, especially concerning the accomplishment of designer babies. The French Chamber of Representatives came in with a new law that banishes the concept of designer babies and replaces it with another concept: double hope babies, in French "bébé du double espoir". A first hope of a pregnancy giving birth to a healthy child and the second being that this child conceived with the aid of PGD could help treat an elder brother. Because of the issuing of two specific laws in a ten years interval, France occupies a privileged place in a Europe where bioethical issues continue to be debated, particularly PGD.
Analytic self-gravitating Skyrmions, cosmological bounces and AdS wormholes
Directory of Open Access Journals (Sweden)
Eloy Ayón-Beato
2016-01-01
Full Text Available We present a self-gravitating, analytic and globally regular Skyrmion solution of the Einstein–Skyrme system with winding number w=±1, in presence of a cosmological constant. The static spacetime metric is the direct product R×S3 and the Skyrmion is the self-gravitating generalization of the static hedgehog solution of Manton and Ruback with unit topological charge. This solution can be promoted to a dynamical one in which the spacetime is a cosmology of the Bianchi type-IX with time-dependent scale and squashing coefficients. Remarkably, the Skyrme equations are still identically satisfied for all values of these parameters. Thus, the complete set of field equations for the Einstein–Skyrme–Λ system in the topological sector reduces to a pair of coupled, autonomous, nonlinear differential equations for the scale factor and a squashing coefficient. These equations admit analytic bouncing cosmological solutions in which the universe contracts to a minimum non-vanishing size, and then expands. A non-trivial byproduct of this solution is that a minor modification of the construction gives rise to a family of stationary, regular configurations in General Relativity with negative cosmological constant supported by an SU(2 nonlinear sigma model. These solutions represent traversable AdS wormholes with NUT parameter in which the only “exotic matter” required for their construction is a negative cosmological constant.
Steady motion of skyrmions and domains walls under diffusive spin torques
Elías, Ricardo Gabriel
2017-03-09
We explore the role of the spin diffusion of conducting electrons in two-dimensional magnetic textures (domain walls and skyrmions) with spatial variation of the order of the spin precession length λex. The effect of diffusion reflects in four additional torques that are third order in spatial derivatives of magnetization and bilinear in λex and in the nonadiabatic parameter β′. In order to study the dynamics of the solitons when these diffusive torques are present, we derive the Thiele equation in the limit of steady motion and we compare the results with the nondiffusive limit. When considering a homogenous current these torques increase the longitudinal velocity of transverse domain walls of width Δ by a factor (λex/Δ)2(α/3), α being the magnetic damping constant. In the case of single skyrmions with core radius r0 these new contributions tend to increase the Magnus effect in an amount proportional to (λex/r0)2(1+2αβ′).
Positron spectroscopy of point defects in the skyrmion-lattice compound MnSi
Reiner, Markus; Bauer, Andreas; Leitner, Michael; Gigl, Thomas; Anwand, Wolfgang; Butterling, Maik; Wagner, Andreas; Kudejova, Petra; Pfleiderer, Christian; Hugenschmidt, Christoph
2016-07-01
Outstanding crystalline perfection is a key requirement for the formation of new forms of electronic order in a vast number of widely different materials. Whereas excellent sample quality represents a standard claim in the literature, there are, quite generally, no reliable microscopic probes to establish the nature and concentration of lattice defects such as voids, dislocations and different species of point defects on the level relevant to the length and energy scales inherent to these new forms of order. Here we report an experimental study of the archetypical skyrmion-lattice compound MnSi, where we relate the characteristic types of point defects and their concentration to the magnetic properties by combining different types of positron spectroscopy with ab-initio calculations and bulk measurements. We find that Mn antisite disorder broadens the magnetic phase transitions and lowers their critical temperatures, whereas the skyrmion lattice phase forms for all samples studied underlining the robustness of this topologically non-trivial state. Taken together, this demonstrates the unprecedented sensitivity of positron spectroscopy in studies of new forms of electronic order.
Critical phenomenon of the near room temperature skyrmion material FeGe
Zhang, Lei; Han, Hui; Ge, Min; Du, Haifeng; Jin, Chiming; Wei, Wensen; Fan, Jiyu; Zhang, Changjin; Pi, Li; Zhang, Yuheng
2016-02-01
The cubic B20 compound FeGe, which exhibits a near room temperature skyrmion phase, is of great importance not only for fundamental physics such as nonlinear magnetic ordering and solitons but also for future application of skyrmion states in spintronics. In this work, the critical behavior of the cubic FeGe is investigated by means of bulk dc-magnetization. We obtain the critical exponents (β = 0.336 ± 0.004, γ = 1.352 ± 0.003 and β = 5.276 ± 0.001), where the self-consistency and reliability are verified by the Widom scaling law and scaling equations. The magnetic exchange distance is found to decay as r-4.9, which is close to the theoretical prediction of 3D-Heisenberg model (r-5). The critical behavior of FeGe indicates a short-range magnetic interaction. Meanwhile, the critical exponents also imply an anisotropic magnetic coupling in this system.
Leibniz algebroids, twistings and exceptional generalized geometry
Baraglia, David
2011-01-01
We investigate a class of Leibniz algebroids which are invariant under diffeomorphisms and symmetries involving collections of closed forms. Under appropriate assumptions we arrive at a classification which in particular gives a construction starting from graded Lie algebras. In this case the Leibniz bracket is a derived bracket and there are higher derived brackets resulting in an $L_\\infty$-structure. The algebroids can be twisted by a non-abelian cohomology class and we prove that the twis...
Vacuum expectation value of twist fields
Belitsky, A. V.
2017-09-01
Twist fields emerge in a number of physical applications ranging from entanglement entropy to scattering amplitudes in four-dimensional gauge theories. In this work, their vacuum expectation values are studied in the path integral framework. By performing a gauge transformation, their correlation functions are reduced to field theory of matter fields in external Aharonov-Bohm vortices. The resulting functional determinants are then analyzed within the zeta-function regularization for the spectrum of Bessel zeros, and concise formulas are derived.
Universal acquired melanosis (Carbon baby
Directory of Open Access Journals (Sweden)
Kaviarasan P
2008-01-01
Full Text Available We report a 3-year-old girl born with fair complexion which became darker. The color change was insidious in onset at the age of 5 months, asymptomatic and progressive involving the entire body surface. Histopathology revealed increased pigmentation of the epidermal basal layer. Universal acquired melanosis is a rare form of hypermelanosis which was synonymously referred to as "Carbon baby". This is a rare presentation with only one earlier case report.
Simulating QCD at the physical point with Nf=2 Wilson twisted mass fermions at maximal twist
International Nuclear Information System (INIS)
Abdel-Rehim, A.; Alexandrou, C.; Cyprus Univ. Nicosia; Burger, F.
2015-12-01
We present simulations of QCD using N f =2 dynamical Wilson twisted mass lattice QCD with physical value of the pion mass and at one value of the lattice spacing. Such simulations at a∼0.09 fm became possible by adding the clover term to the action. While O(a) improvement is still guaranteed by Wilson twisted mass fermions at maximal twist, the introduction of the clover term reduces O(a 2 ) cutoff effects related to isospin symmetry breaking. We give results for a set of phenomenologically interesting observables like pseudo-scalar masses and decay constants, quark masses and the anomalous magnetic moments of leptons. We mostly find remarkably good agreement with phenomenology, even though we cannot take the continuum and thermodynamic limits.
Bhattacharya, Dhritiman; Mamun Al-Rashid, Md; Atulasimha, Jayasimha
2017-10-01
Recent work (P-H Jang et al 2015 Appl. Phys. Lett. 107 202401, J. Sampaio et al 2016 Appl. Phys. Lett. 108 112403) suggests that ferromagnetic reversal with spin transfer torque (STT) requires more current in a system in the presence of Dzyaloshinskii-Moriya interaction (DMI) than switching a typical ferromagnet of the same dimensions and perpendicular magnetic anisotropy (PMA). However, DMI promotes the stabilization of skyrmions and we report that when perpendicular anisotropy is modulated (reduced) for both the skyrmion and ferromagnet, it takes a much smaller current to reverse the fixed skyrmion than to reverse the ferromagnet in the same amount of time, or the skyrmion reverses much faster than the ferromagnet at similar levels of current. We show with rigorous micromagnetic simulations that skyrmion switching proceeds along a different path at very low PMA, which results in a significant reduction in the spin current or time required for reversal. This can offer potential for memory applications where a relatively simple modification of the standard STT-RAM (to include a heavy metal adjacent to the soft magnetic layer and with appropriate design of the tunnel barrier) can lead to an energy efficient and fast magnetic memory device based on the reversal of fixed skyrmions.
Twisted sigma-model solitons on the quantum projective line
Landi, Giovanni
2018-04-01
On the configuration space of projections in a noncommutative algebra, and for an automorphism of the algebra, we use a twisted Hochschild cocycle for an action functional and a twisted cyclic cocycle for a topological term. The latter is Hochschild-cohomologous to the former and positivity in twisted Hochschild cohomology results into a lower bound for the action functional. While the equations for the critical points are rather involved, the use of the positivity and the bound by the topological term lead to self-duality equations (thus yielding twisted noncommutative sigma-model solitons, or instantons). We present explicit nontrivial solutions on the quantum projective line.
Twisted rudder for reducing fuel-oil consumption
Directory of Open Access Journals (Sweden)
Kim Jung-Hun
2014-09-01
Full Text Available Three twisted rudders fit for large container ships have been developed; 1 the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2 the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3 the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed
Twisted rudder for reducing fuel-oil consumption
Directory of Open Access Journals (Sweden)
Jung-Hun Kim
2014-09-01
Full Text Available Three twisted rudders fit for large container ships have been developed; 1 the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2 the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3 the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed.
Twisted rudder for reducing fuel-oil consumption
Kim, Jung-Hun; Choi, Jung-Eun; Choi, Bong-Jun; Chung, Seok-Ho
2014-09-01
Three twisted rudders fit for large container ships have been developed; 1) the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2) the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3) the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed
Higher twist contributions to deep-inelastic structure functions
International Nuclear Information System (INIS)
Bluemlein, J.; Boettcher, H.
2008-07-01
We report on a recent extraction of the higher twist contributions to the deep inelastic structure functions F ep,ed 2 (x,Q 2 ) in the large x region. It is shown that the size of the extracted higher twist contributions is strongly correlated with the higher order corrections applied to the leading twist part. A gradual lowering of the higher twist contributions going from NLO to N 4 LO is observed, where in the latter case only the leading large x terms were considered. (orig.)
NMSBA - Twist Resist - Rotational Exercise Module
Energy Technology Data Exchange (ETDEWEB)
Walker, Aaron [Twist Resist, Albuquerque, NM (United States); Reece, Blake D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Berger, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guido, Steven Frank [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Linker, Taylor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2016-08-01
This report contains a summary of the work completed to develop a modular, rotational exercise device. In the report are images, diagrams, and explanations of the efforts contributed to the project since its inception. The purpose of this document is to provide a walk-through of the progress on this project, from the initial design concepts to the final design and work done, so that the customer (Twist Resist), or individuals/firms who work on this project in the future will have a springboard of ideas/concepts to work from.
MODERN PRODUCTS FOR FEEDING PREMATURE BABIES
Directory of Open Access Journals (Sweden)
A. V. Surzhik
2012-01-01
Full Text Available In recent decades there has been substantial progress in the technology of premature infants nursing, especially with extremely low birth weight. Adequate feeding is one of the fundamental factors of premature babies nursing. To ensure a premature baby with all necessary components for power saving in breast milk intake, breast milk fortifiers — specifically developed additives that adjust the composition of food for premature babies, are used for more than 20 years (for premature babies receiving breast milk. On the one hand, to preserve all benefits of breastfeeding, on the other — to prevent the deficit development of necessary elements for adequate growth and development of nutrients.
7 CFR 319.56-43 - Baby corn and baby carrots from Zambia.
2010-01-01
... 7 Agriculture 5 2010-01-01 2010-01-01 false Baby corn and baby carrots from Zambia. 319.56-43... § 319.56-43 Baby corn and baby carrots from Zambia. (a) Immature, dehusked “baby” sweet corn (Zea mays L..., which is a field, where the corn has been grown must have been inspected at least once during the...
Self-dual Skyrmions on the spheres S2 N +1
Amari, Y.; Ferreira, L. A.
2018-04-01
We construct self-dual sectors for scalar field theories on a (2 N +2 )-dimensional Minkowski space-time with the target space being the 2 N +1 -dimensional sphere S2 N +1. The construction of such self-dual sectors is made possible by the introduction of an extra functional in the action that renders the static energy and the self-duality equations conformally invariant on the (2 N +1 )-dimensional spatial submanifold. The conformal and target-space symmetries are used to build an ansatz that leads to an infinite number of exact self-dual solutions with arbitrary values of the topological charge. The five-dimensional case is discussed in detail, where it is shown that two types of theories admit self-dual sectors. Our work generalizes the known results in the three-dimensional case that lead to an infinite set of self-dual Skyrmion solutions.
The half-skyrmion phase in a chiral-quark model
International Nuclear Information System (INIS)
Mantovani Sarti, Valentina; Vento, Vicente
2014-01-01
The Chiral Dilaton Model, where baryons arise as non-topological solitons built from the interaction of quarks and chiral mesons, shows in the high density low temperature regime a two phase scenario in the nuclear matter phase diagram. Dense soliton matter described by the Wigner–Seitz approximation generates a periodic potential in terms of the sigma and pion fields that leads to the formation of a band structure. The analysis up to three times nuclear matter density shows that soliton matter undergoes two separate phase transitions: a delocalization of the baryon number density leading to B=1/2 structures, as in skyrmion matter, at moderate densities, and quark deconfinement at larger densities. This description fits well into the so-called quarkyonic phase where, before deconfinement, nuclear matter should undergo structural changes involving the restoration of fundamental symmetries of QCD
Neutron diffractive imaging of the skyrmion lattice nucleation in MnSi
Reimann, T.; Bauer, A.; Pfleiderer, C.; Böni, P.; Trtik, P.; Tremsin, A.; Schulz, M.; Mühlbauer, S.
2018-01-01
Spatially resolved neutron diffractive imaging with a microchannel plate collimator is used to directly map the nucleation of the skyrmion lattice (SkL) of the B20 compound MnSi at the conical to SkL transition as a function of magnetic field. Our study shows a macroscopic phase separation of the SkL and the conical phase at the border of the SkL phase pocket, reveals that the nucleation of the SkL starts at the edges of the sample, and quantifies the bending of the SkL due to demagnetization. Our study highlights the importance of geometric and demagnetizing effects for the SkL formation regarding the unambiguous interpretation of measurements of bulk properties such as possible phase coexistence and crossover regimes.
Can Babies Learn to Read? A Randomized Trial of Baby Media
Neuman, Susan B.; Kaefer, Tanya; Pinkham, Ashley; Strouse, Gabrielle
2014-01-01
Targeted to children as young as 3 months old, there is a growing number of baby media products that claim to teach babies to read. This randomized controlled trial was designed to examine this claim by investigating the effects of a best-selling baby media product on reading development. One hundred and seventeen infants, ages 9 to 18 months,…
Drag Performance of Twist Morphing MAV Wing
Directory of Open Access Journals (Sweden)
Ismail N.I.
2016-01-01
Full Text Available Morphing wing is one of latest evolution found on MAV wing. However, due to few design problems such as limited MAV wing size and complicated morphing mechanism, the understanding of its aerodynamic behaviour was not fully explored. In fact, the basic drag distribution induced by a morphing MAV wing is still remained unknown. Thus, present work is carried out to compare the drag performance between a twist morphing wing with membrane and rigid MAV wing design. A quasi-static aeroelastic analysis by using the Ansys-Fluid Structure Interaction (FSI method is utilized in current works to predict the drag performance a twist morphing MAV wing design. Based on the drag pattern study, the results exhibits that the morphing wing has a partial similarities in overall drag pattern with the baseline (membrane and rigid wing. However, based CD analysis, it shows that TM wing induced higher CD magnitude (between 25% to 82% higher than to the baseline wing. In fact, TM wing also induced the largest CD increment (about 20% to 27% among the wings. The visualization on vortex structure revealed that TM wing also produce larger tip vortex structure (compared to baseline wings which presume to promote higher induce drag component and subsequently induce its higher CD performance.
Computational design of an automotive twist beam
Directory of Open Access Journals (Sweden)
Benki Aalae
2016-07-01
Full Text Available In recent years, the automotive industry has known a remarkable development in order to satisfy the customer requirements. In this paper, we will study one of the components of the automotive which is the twist beam. The study is focused on the multicriteria design of the automotive twist beam undergoing linear elastic deformation (Hooke׳s law. Indeed, for the design of this automotive part, there are some criteria to be considered as the rigidity (stiffness and the resistance to fatigue. Those two criteria are known to be conflicting, therefore, our aim is to identify the Pareto front of this problem. To do this, we used a Normal Boundary Intersection (NBI algorithm coupling with a radial basis function (RBF metamodel in order to reduce the high calculation time needed for solving the multicriteria design problem. Otherwise, we used the free form deformation (FFD technique for the generation of the 3D shapes of the automotive part studied during the optimization process.
How the embryonic brain tube twists
Chen, Zi; Guo, Qiaohang; Forsch, Nickolas; Taber, Larry
2014-03-01
During early development, the tubular brain of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This deformation is one of the major organ-level symmetry-breaking events in development. Available evidence suggests that bending is caused by differential growth, but the mechanism for torsion remains poorly understood. Since the heart almost always loops in the same direction that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is virtually nonexistent, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. In addition, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model is used to interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''.
Strong CP, flavor, and twisted split fermions
International Nuclear Information System (INIS)
Harnik, Roni; Perez, Gilad; Schwartz, Matthew D.; Shirman, Yuri
2005-01-01
We present a natural solution to the strong CP problem in the context of split fermions. By assuming CP is spontaneously broken in the bulk, a weak CKM phase is created in the standard model due to a twisting in flavor space of the bulk fermion wavefunctions. But the strong CP phase remains zero, being essentially protected by parity in the bulk and CP on the branes. As always in models of spontaneous CP breaking, radiative corrections to theta bar from the standard model are tiny, but even higher dimension operators are not that dangerous. The twisting phenomenon was recently shown to be generic, and not to interfere with the way that split fermions naturally weaves small numbers into the standard model. It follows that out approach to strong CP is compatible with flavor, and we sketch a comprehensive model. We also look at deconstructed version of this setup which provides a viable 4D model of spontaneous CP breaking which is not in the Nelson-Barr class. (author)
Needleless electrospinning with twisted wire spinneret
International Nuclear Information System (INIS)
Holopainen, Jani; Penttinen, Toni; Santala, Eero; Ritala, Mikko
2015-01-01
A needleless electrospinning setup named ‘Needleless Twisted Wire Electrospinning’ was developed. The polymer solution is electrospun from the surface of a twisted wire set to a high voltage and collected on a cylindrical collector around the wire. Multiple Taylor cones are simultaneously self-formed on the downward flowing solution. The system is robust and simple with no moving parts aside from the syringe pump used to transport the solution to the top of the wire. The structure and process parameters of the setup and the results on the preparation of polyvinyl pyrrolidone (PVP), hydroxyapatite (HA) and bioglass fibers with the setup are presented. PVP fiber sheets with areas of 40 × 120 cm 2 and masses up to 1.15 g were prepared. High production rates of 5.23 g h −1 and 1.40 g h −1 were achieved for PVP and HA respectively. The major limiting factor of the setup is drying of the polymer solution on the wire during the electrospinning process which will eventually force to interrupt the process for cleaning of the wire. Possible solutions to this problem and other ways to develop the setup are discussed. The presented system provides a simple way to increase the production rate and area of fiber sheet as compared with the conventional needle electrospinning. (paper)
von Bergmann, Kirsten; Kubetzka, André; Pietzsch, Oswald; Wiesendanger, Roland
2014-10-01
The spin textures of ultra-thin magnetic layers exhibit surprising variety. The loss of inversion symmetry at the interface of the magnetic layer and substrate gives rise to the so-called Dzyaloshinskii-Moriya interaction which favors non-collinear spin arrangements with unique rotational sense. Here we review the application of spin-polarized scanning tunneling microscopy to such systems, which has led to the discovery of interface-induced chiral domain walls and spin spirals. Recently, different interface-driven skyrmion lattices have been found, and the writing as well as the deleting of individual skyrmions based on local spin-polarized current injection has been demonstrated. These interface-induced non-collinear magnetic states offer new exciting possibilities to study fundamental magnetic interactions and to tailor material properties for spintronic applications.
Bend-twist coupling potential of wind turbine blades
DEFF Research Database (Denmark)
Fedorov, Vladimir; Berggreen, Christian
2014-01-01
-twist coupling magnitude of up to 0.2 is feasible to achieve in the baseline blade structure made of glass-fiber reinforced plastics. Further, by substituting the glass-fibers with carbon-fibers the coupling effect can be increased to 0.4. Additionally, the effect of introduction of bend-twist coupling...
Design optimization of a twist compliant mechanism with nonlinear stiffness
Tummala, Y.; Frecker, M. I.; Wissa, A. A.; Hubbard, J. E., Jr.
2014-10-01
A contact-aided compliant mechanism called a twist compliant mechanism (TCM) is presented in this paper. This mechanism has nonlinear stiffness when it is twisted in both directions along its axis. The inner core of the mechanism is primarily responsible for its flexibility in one twisting direction. The contact surfaces of the cross-members and compliant sectors are primarily responsible for its high stiffness in the opposite direction. A desired twist angle in a given direction can be achieved by tailoring the stiffness of a TCM. The stiffness of a compliant twist mechanism can be tailored by varying thickness of its cross-members, thickness of the core and thickness of its sectors. A multi-objective optimization problem with three objective functions is proposed in this paper, and used to design an optimal TCM with desired twist angle. The objective functions are to minimize the mass and maximum von-Mises stress observed, while minimizing or maximizing the twist angles under specific loading conditions. The multi-objective optimization problem proposed in this paper is solved for an ornithopter flight research platform as a case study, with the goal of using the TCM to achieve passive twisting of the wing during upstroke, while keeping the wing fully extended and rigid during the downstroke. Prototype TCMs have been fabricated using 3D printing and tested. Testing results are also presented in this paper.
Design optimization of a twist compliant mechanism with nonlinear stiffness
International Nuclear Information System (INIS)
Tummala, Y; Frecker, M I; Wissa, A A; Hubbard, J E Jr
2014-01-01
A contact-aided compliant mechanism called a twist compliant mechanism (TCM) is presented in this paper. This mechanism has nonlinear stiffness when it is twisted in both directions along its axis. The inner core of the mechanism is primarily responsible for its flexibility in one twisting direction. The contact surfaces of the cross-members and compliant sectors are primarily responsible for its high stiffness in the opposite direction. A desired twist angle in a given direction can be achieved by tailoring the stiffness of a TCM. The stiffness of a compliant twist mechanism can be tailored by varying thickness of its cross-members, thickness of the core and thickness of its sectors. A multi-objective optimization problem with three objective functions is proposed in this paper, and used to design an optimal TCM with desired twist angle. The objective functions are to minimize the mass and maximum von-Mises stress observed, while minimizing or maximizing the twist angles under specific loading conditions. The multi-objective optimization problem proposed in this paper is solved for an ornithopter flight research platform as a case study, with the goal of using the TCM to achieve passive twisting of the wing during upstroke, while keeping the wing fully extended and rigid during the downstroke. Prototype TCMs have been fabricated using 3D printing and tested. Testing results are also presented in this paper. (paper)
Two new twisted helical nickel (II) and cobalt (III) octahedral ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 6. Two new twisted helical nickel(II) and cobalt(III) octahedral monomer complexes: Synthesis and structural characterization. Malay Dolai ... Keywords. Coordination chemistry; nickel(II); cobalt(III); Schiff base; twisted helicity; supramolecular interactions.
Twisted Acceleration-Enlarged Newton-Hooke Hopf Algebras
International Nuclear Information System (INIS)
Daszkiewicz, M.
2010-01-01
Ten Abelian twist deformations of acceleration-enlarged Newton-Hooke Hopf algebra are considered. The corresponding quantum space-times are derived as well. It is demonstrated that their contraction limit τ → ∞ leads to the new twisted acceleration-enlarged Galilei spaces. (author)
Quadratic Twists of Rigid Calabi–Yau Threefolds Over
DEFF Research Database (Denmark)
Gouvêa, Fernando Q.; Kiming, Ian; Yui, Noriko
2013-01-01
of weight 4 on some Γ 0(N). We show that quadratic twisting of a threefold corresponds to twisting the attached newform by quadratic characters and illustrate with a number of obvious and not so obvious examples. The question is motivated by the deeper question of which newforms of weight 4 on some Γ 0(N...
Twisted tubular photobioreactor fluid dynamics evaluation for energy consumption minimization
Gómez-Pérez, C.A.; Espinosa Oviedo, J.J.; Montenegro Ruiz, L.C.; Boxtel, van A.J.B.
2017-01-01
This paper discusses a new tubular PhotoBioReactor (PBR) called twisted tubular PBR. The geometry of a twisted tubular PBR induces swirl mixing to guarantee good exposure of microalgae to Light-Dark (LD) cycles and to the nutrients and dissolved CO 2 . The paper analyses the energy uptake for fluid
KINEMATIC PROFILES OF DUMBBELL GALAXIES WITH TWISTED RADIO JETS
BALCELLS, M; MORGANTI, R; OOSTERLOO, T; PEREZFOURNON, [No Value; GONZALEZSERRANO, JI
1995-01-01
We study the orbital properties of dumbbell galaxies which harbor twisted radio jets. Velocity and velocity dispersion profiles for four dumbbell pairs (3C66B, 3C75, 3C449, 0326+39) are presented. We analyze optical CCD images in search of isophote off-centering and large isophote twists. Combining
Twists of genus three curves over finite fields
Meagher, Stephen; Top, Jakob
In this article we recall how to describe the twists of a curve over a finite field and we show how to compute the number of rational points on such a twist by methods of linear algebra We illustrate this in the case of plane quartic curves with at least 16 automorphisms In particular we treat the
Enhancement of heat transfer using varying width twisted tape inserts
African Journals Online (AJOL)
Enhancement of heat transfer using varying width twisted tape inserts. ... International Journal of Engineering, Science and Technology ... The present work shows the results obtained from experimental investigations of the augmentation of turbulent flow heat transfer in a horizontal tube by means of varying width twisted ...
Analysis list: Twist1 [Chip-atlas[Archive
Lifescience Database Archive (English)
Full Text Available Twist1 Embryo,Neural + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Tw...ist1.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Twist1.5.tsv http://dbarchive.biosciencedbc....jp/kyushu-u/mm9/target/Twist1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Twist1.Embryo.tsv,http://dbarchive.bioscien...cedbc.jp/kyushu-u/mm9/colo/Twist1.Neural.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/colo/Embryo.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Neural.gml ...
Development of Baby-EBM Interface System
International Nuclear Information System (INIS)
Mukhlis Mokhtar; Abu Bakar Ghazali; Muhammad Zahidee Taat
2010-01-01
This paper explains the works being done to develop an interface system for Baby-Electron Beam Machine (EBM). The function of the system is for the safety, controlling and monitoring the Baby-EBM. The integration for the system is using data acquisition (DAQ) hardware and LabVIEW to develop the software. (author)
MONITORING BABY INCUBATOR SENTRAL DENGAN KOMUNIKASI WIRELESS
Directory of Open Access Journals (Sweden)
Ary Sulistyo Utomo
2018-04-01
180m. Pengujian suhu ruang baby incubator menggunakan termometer sebagai perbandingan dengan nilai suhu yang dibaca pada alat. Dari pengukuran diperoleh tingkat perbedaan 0% pada suhu 30oC dan 2,8% pada suhu 37oC. Kata kunci: baby incubator, sistem monitoring sentral, microsoft visual studio, arduino.
Preparing Your Family for a New Baby
... can be very helpful. So can sibling classes (ask your hospital if it offers them). Try to tell your child before he hears about the new ... role to play in caring for the baby. Tell her she can hold the baby, although she must ask you first. Praise her when she is gentle ...
Newborn Screening Tests for your Baby
... oxygen in your baby’s blood by using a sensor attached to his finger or foot. This test is used to screen babies for a group of heart conditions called critical congenital heart disease (CCHD). Your baby gets this test before he ...
Welcoming a New Baby into Your Family
... play peek-a-boo with you. They're just getting adjusted to the world. In time, your baby sister or brother will be able ... good time to ask your mom or dad to spend a little time together — just the two of you. When a new baby ...
Three-parent baby: is it ethical?
Dahiya, Neha; Garg, Suneela
2017-11-14
The UK was the first country to legalise mitochondrial donation in October 2015. In 2016, the first three-parent baby was born in Mexico and the US Food and Drug Administration declared that further research on mitochondrial donation is ethically permissible. It has now become an important issue, raising as it does, the spectre of "genetically modified designer babies".
Designer Babies: Eugenics Repackaged or Consumer Options?
Baird, Stephen L.
2007-01-01
"Designer babies" is a term used by journalists and commentators--not by scientists--to describe several different reproductive technologies. These technologies have one thing in common: they give parents more control over what their offspring will be like. Designer babies are made possible by progress in three fields: (1) Advanced…
‘Baby Blues’ highbush blueberry
‘Baby Blues’ is a new highbush blueberry from the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) breeding program in Corvallis, OR, released in cooperation with Oregon State University’s Agricultural Experiment Station. ‘Baby Blues’ is a vigorous, high-yielding, very small-f...
Motor Development Programming in Trisomic-21 Babies
Sanz, Teresa; Menendez, Javier; Rosique, Teresa
2011-01-01
The present study contributes to the understanding of gross motor development in babies with Down's syndrome. Also, it facilitates the comprehension of the efficiency of the early motor stimulation as well as of beginning it as early as possible. We worked with two groups of babies with Down's syndrome, beginning the early motor training in each…
Teen Moms and Babies Benefit from Camping.
Goode, Marsha; Broesamle, Barbara
1987-01-01
Describes nine-day residential camp for Michigan teenage mothers/babies to enhance personal growth and develop responsible social skills. Outlines goals, pre-camp planning, staff, activities, evaluation. Reports 31 teen moms (ages 13-21) and 35 babies attended in 1986. Indicates participants were in therapy, experienced abuse, had low self-esteem,…
Giant lower oesophageal ulcer Bushman baby
African Journals Online (AJOL)
1983-02-26
Feb 26, 1983 ... Giant lower oesophageal ulcer. Bushman baby. A case report. J. J. HEYDENRYCH, A. D. KEET. •. ID a. Summary. The case of a giant, penetrating lower oesophageal ulcer in a 14-month-old Bushman baby is reported. ... crying precluded a thorough systematic examination. Food was immediately rejected.
MHD Sausage Waves in Compressible Magnetically Twisted Flux Tubes
Fedun, Viktor
Recent high-resolution satellites clearly prove the existence of various types of theoretically predicted MHD waves in solar atmospheric magnetic structures (loops, arcades ets). Oscillations of magnetic flux tubes are of great importance as they contain information about the geometry and fine structure of the flux tubes. In this work we study the details of the effects caused by the presence of magnetic twist in flux tubes. The propagation of surface and body linear MHD modes in a twisted magnetic flux tube embedded in a magnetically twisted plasma environment is considered. We derive and analytically solve the linear governing equations of wave propagation for sausage surface and body modes of a magnetically-twisted compressible flux tube embedded in a compressible uniformly-magnetized plasma environment in cylindrical geometry in terms of Kummer's functions. Numerical solutions for the phase velocity are obtained for a wide range of wavenumbers and for varying magnetic twist. The effect of magnetic twist on the period of oscillations of sausage surface modes for different values of the wavenumber and vertical magnetic field strength is calculated for representative photospheric and coronal conditions. These results generalize and extend previous studies of MHD waves obtained for incompressible or compressible but non-twisted flux tubes. It is found that magnetic twist may change the period of sausage surface waves by the order of a few per cent when compared to counterparts in straight non-twisted flux tubes. This information will be most relevant, when high-resolution observations are used for diagnostic exploration of MHD wave guides in analogy to solar-interior studies by means of global eigenoscillations in helioseismology. Further detailed analysis is necessary in order to find the dispersion relation for more realistic cases, where the magnetic twist diminishes with distance from the tube. Finally, observational relevances will be discussed in light of the
Expression of EMT Markers SLUG and TWIST in Breast Cancer.
Grzegrzolka, Jedrzej; Biala, Martyna; Wojtyra, Patrycja; Kobierzycki, Christopher; Olbromski, Mateusz; Gomulkiewicz, Agnieszka; Piotrowska, Aleksandra; Rys, Janusz; Podhorska-Okolow, Marzena; Dziegiel, Piotr
2015-07-01
The epithelial-mesenchymal transition (EMT) has been observed in progression of in situ breast cancer to the invasive form and might be initiated by snail family zinc finger 2 (SLUG) and twist family bHLH transcription factor 1 (TWIST) protein overexpression. During this phenomenon, cells lose their epithelial phenotype and acquire mesenchymal features. The aim of the study was to examine the association of EMT markers SLUG and TWIST with clinicopathological data and the possibility of using these proteins as prognostic markers of breast cancer. Immunohistochemical analysis (IHC) of SLUG and TWIST expression was performed on archival paraffin samples of 19 cases with fibrocystic breast changes (control group), 148 cases of invasive ductal breast cancer (IDC) and 26 of invasive lobular breast cancer (ILC). Laser capture microdissection for isolation of cells from 17 frozen samples of IDC was employed and subsequently SLUG and TWIST mRNA expression in cancer and stromal cells was detected separately by real-time polymerase chain reaction. SLUG and TWIST expression in IDC was significant higher in stromal cells regardless of the method of quantification used (pSLUG mRNA, and pSLUG IHC, TWIST IHC and TWIST mRNA expression). Positive correlation of SLUG and TWIST protein and mRNA expression was observed in stromal cells of IDC (r=0.347; p<0.0001 and r=0.704; p<0.01, respectively). Expression of TWIST protein in IDC was higher in cancer cells of cases with shorter event-free survival period, as well as in stromal cells of cases with shorter overall survival period (p<0.05 for both). Stromal cells could play a role in the regulation of EMT in breast cancer. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.
Resuscitating the Baby after Shoulder Dystocia
Directory of Open Access Journals (Sweden)
Savas Menticoglou
2016-01-01
Full Text Available Background. To propose hypovolemic shock as a possible explanation for the failure to resuscitate some babies after shoulder dystocia and to suggest a change in clinical practice. Case Presentation. Two cases are presented in which severe shoulder dystocia was resolved within five minutes. Both babies were born without a heartbeat. Despite standard resuscitation by expert neonatologists, no heartbeat was obtained until volume resuscitation was started, at 25 minutes in the first case and 11 minutes in the second. After volume resuscitation circulation was restored, there was profound brain damage and the babies died. Conclusion. Unsuspected hypovolemic shock may explain some cases of failed resuscitation after shoulder dystocia. This may require a change in clinical practice. Rather than immediately clamping the cord after the baby is delivered, it is proposed that (1 the obstetrician delay cord clamping to allow autotransfusion of the baby from the placenta and (2 the neonatal resuscitators give volume much sooner.
Resuscitating the Baby after Shoulder Dystocia
2016-01-01
Background. To propose hypovolemic shock as a possible explanation for the failure to resuscitate some babies after shoulder dystocia and to suggest a change in clinical practice. Case Presentation. Two cases are presented in which severe shoulder dystocia was resolved within five minutes. Both babies were born without a heartbeat. Despite standard resuscitation by expert neonatologists, no heartbeat was obtained until volume resuscitation was started, at 25 minutes in the first case and 11 minutes in the second. After volume resuscitation circulation was restored, there was profound brain damage and the babies died. Conclusion. Unsuspected hypovolemic shock may explain some cases of failed resuscitation after shoulder dystocia. This may require a change in clinical practice. Rather than immediately clamping the cord after the baby is delivered, it is proposed that (1) the obstetrician delay cord clamping to allow autotransfusion of the baby from the placenta and (2) the neonatal resuscitators give volume much sooner. PMID:27493815
PREBIOTICS, INULIN AND BABY FOODS
Directory of Open Access Journals (Sweden)
S.V. Bel’mer
2010-01-01
Full Text Available Prebiotics play significant role in life support of microorganisms of human gastrointestinal tract, and normal functional state of intestinal biocenosis is sufficient condition for human health. Intestinal microbiocenosis is a component of regulation of proteins and lipids metabolism, vitamins synthesis, detoxication process in intestine, etc. prebiotics include a number of disaccharides (lactulose, oligosaccharides and polysaccharides (inulin, cellulose, etc.. Fructose polymer — inulin — provides growth of bifido- and lactobacteria, improves metabolism and has immunomodulating activity. Formation of intestinal micro biocenosis in infant is provided by prebiotics of breast milk. Further state of micro biocenosis, which is necessary for growth and development of child, is determined by adequate intake of prebiotics from fruits, vegetables and cereals. It is reasonable to use special baby foods fortified with prebiotics (for example, inulin.Key words: prebiotics, intestinal microflora, inulin.(Voprosy sovremennoi pediatrii — Current Pediatrics. – 2010;9(3:121-125
Bianisotropic metamaterials based on twisted asymmetric crosses
International Nuclear Information System (INIS)
Reyes-Avendaño, J A; Sampedro, M P; Juárez-Ruiz, E; Pérez-Rodríguez, F
2014-01-01
The effective bianisotropic response of 3D periodic metal-dielectric structures, composed of crosses with asymmetrically-cut wires, is investigated within a general homogenization theory using the Fourier formalism and the form-factor division approach. It is found that the frequency dependence of the effective permittivity for a system of periodically-repeated layers of metal crosses exhibits two strong resonances, whose separation is due to the cross asymmetry. Besides, bianisotropic metamaterials, having a base of four twisted asymmetric crosses, are proposed. The designed metamaterials possess negative refractive index at frequencies determined by the cross asymmetry, the gap between the arms of adjacent crosses lying on the same plane, and the type of Bravais lattice. (papers)
Twisted Polynomials and Forgery Attacks on GCM
DEFF Research Database (Denmark)
Abdelraheem, Mohamed Ahmed A. M. A.; Beelen, Peter; Bogdanov, Andrey
2015-01-01
nonce misuse resistance, such as POET. The algebraic structure of polynomial hashing has given rise to security concerns: At CRYPTO 2008, Handschuh and Preneel describe key recovery attacks, and at FSE 2013, Procter and Cid provide a comprehensive framework for forgery attacks. Both approaches rely...... heavily on the ability to construct forgery polynomials having disjoint sets of roots, with many roots (“weak keys”) each. Constructing such polynomials beyond naïve approaches is crucial for these attacks, but still an open problem. In this paper, we comprehensively address this issue. We propose to use...... in an improved key recovery algorithm. As cryptanalytic applications of our twisted polynomials, we develop the first universal forgery attacks on GCM in the weak-key model that do not require nonce reuse. Moreover, we present universal weak-key forgeries for the nonce-misuse resistant AE scheme POET, which...
Unusual presentation of twisted ovarian cyst
Directory of Open Access Journals (Sweden)
Vineet V Mishra
2016-01-01
Full Text Available Ovarian torsion (also termed as adnexal torsion refers to partial or complete rotation of the ovary and a portion of fallopian tube along its supplying vascular pedicle. It occurs commonly in reproductive age group; more on the right side (60% and often presents with acute lower abdominal pain lasting for few hours and up to 24 h, accounting for 2.7% of acute gynecological conditions. It is one of the devastating conditions, hampering blood supply of ovary which may lead to total necrosis of ovarian tissue and complications, if not diagnosed and managed in time. Hence, we present a case on a twisted ovarian cyst in postmenopausal woman with unusual symptomatology leading to delayed diagnosis and loss of an ovary.
International Nuclear Information System (INIS)
Obregon, Octavio; Quevedo, Hernando; Ryan, Michael P.
2004-01-01
We construct a family of time and angular dependent, regular S-brane solutions which corresponds to a simple analytical continuation of the Zipoy-Voorhees 4-dimensional vacuum spacetime. The solutions are asymptotically flat and turn out to be free of singularities without requiring a twist in space. They can be considered as the simplest non-singular generalization of the singular S0-brane solution. We analyze the properties of a representative of this family of solutions and show that it resembles to some extent the asymptotic properties of the regular Kerr S-brane. The R-symmetry corresponds, however, to the general lorentzian symmetry. Several generalizations of this regular solution are derived which include a charged S-brane and an additional dilatonic field. (author)
Chiral Response of Twisted Bilayer Graphene
Stauber, T.; Low, T.; Gómez-Santos, G.
2018-01-01
We present an effective (minimal) theory for chiral two-dimensional materials. These materials possess an electromagnetic coupling without exhibiting a topological gap. As an example, we study the response of doped twisted bilayers, unveiling unusual phenomena in the zero frequency limit. An in-plane magnetic field induces a huge paramagnetic response at the neutrality point and, upon doping, also gives rise to a substantial longitudinal Hall response. The system also accommodates nontrivial longitudinal plasmonic modes that are associated with a longitudinal magnetic moment, thus endowing them with a chiral character. Finally, we note that the optical activity can be considerably enhanced upon doping and our general approach would enable systematic exploration of 2D material heterostructures with optical activity.
Emission of twisted photons from quantum vacuum
Mendonça, J. T.
2017-12-01
Emission of twisted photons, carrying orbital angular momentum, from QED vacuum is considered. This is a new type of radiation which can be excited by a Gaussian laser pulse propagating along the axis of a magnetic wiggler. We consider quantum vacuum as described by the Heisenberg-Euler Lagrangian, and assume propagation of an ultra-intense laser pulse in a static magnetic structure. We show that, in such a configuration, vacuum emission of electromagnetic vortices can occur, at a frequency much larger than that of the intense laser pulse, which can eventually be tuned from the visible up to the XUV range. This new configuration could eventually be useful to reduce classical noise in future experiments.
Dynamical twisted mass fermions and baryon spectroscopy
International Nuclear Information System (INIS)
Drach, V.
2010-06-01
The aim of this work is an ab initio computation of the baryon masses starting from quantum chromodynamics (QCD). This theory describes the interaction between quarks and gluons and has been established at high energy thanks to one of its fundamental properties: the asymptotic freedom. This property predicts that the running coupling constant tends to zero at high energy and thus that perturbative expansions in the coupling constant are justified in this regime. On the contrary the low energy dynamics can only be understood in terms of a non perturbative approach. To date, the only known method that allows the computation of observables in this regime together with a control of its systematic effects is called lattice QCD. It consists in formulating the theory on an Euclidean space-time and to evaluating numerically suitable functional integrals. First chapter is an introduction to the QCD in the continuum and on a discrete space time. The chapter 2 describes the formalism of maximally twisted fermions used in the European Twisted Mass (ETM) collaboration. The chapter 3 deals with the techniques needed to build hadronic correlator starting from gauge configuration. We then discuss how we determine hadron masses and their statistical errors. The numerical estimation of functional integral is explained in chapter 4. It is stressed that it requires sophisticated algorithm and massive parallel computing on Blue-Gene type architecture. Gauge configuration production is an important part of the work realized during my Ph.D. Chapter 5 is a critical review on chiral perturbation theory in the baryon sector. The two last chapter are devoted to the analysis in the light and strange baryon sector. Systematics and chiral extrapolation are extensively discussed. (author)
Structural and electron diffraction scaling of twisted graphene bilayers
Zhang, Kuan; Tadmor, Ellad B.
2018-03-01
Multiscale simulations are used to study the structural relaxation in twisted graphene bilayers and the associated electron diffraction patterns. The initial twist forms an incommensurate moiré pattern that relaxes to a commensurate microstructure comprised of a repeating pattern of alternating low-energy AB and BA domains surrounding a high-energy AA domain. The simulations show that the relaxation mechanism involves a localized rotation and shrinking of the AA domains that scales in two regimes with the imposed twist. For small twisting angles, the localized rotation tends to a constant; for large twist, the rotation scales linearly with it. This behavior is tied to the inverse scaling of the moiré pattern size with twist angle and is explained theoretically using a linear elasticity model. The results are validated experimentally through a simulated electron diffraction analysis of the relaxed structures. A complex electron diffraction pattern involving the appearance of weak satellite peaks is predicted for the small twist regime. This new diffraction pattern is explained using an analytical model in which the relaxation kinematics are described as an exponentially-decaying (Gaussian) rotation field centered on the AA domains. Both the angle-dependent scaling and diffraction patterns are in quantitative agreement with experimental observations. A Matlab program for extracting the Gaussian model parameters accompanies this paper.
International Nuclear Information System (INIS)
Jackson, A.D.; Weiss, C.; Wirzba, A.
1990-01-01
The Skyrme model has the same high density behavior as a free quark gas. However, the inclusion of higher-order terms spoils this agreement. We consider the all-order sum of a class of chiral invariant Lagrangians of even order in L μ suggested by Marleau. We prove Marleau's conjecture that these terms are of second order in the derivatives of the chiral angle for the hedgehog case and show the terms are unique under the additional condition that, for each order, the identity map on the 3-sphere S 3 (L) is a solution. The general form of the summation can be restricted by physical constraints leading to stable results. Under the assumption that the Lagrangian scales like the non-linear sigma model at low densities and like the free quark gas at high densities, we prove that a chiral phase transition must occur. (orig.)
Topological duality twist and brane instantons in F-theory
Martucci, Luca
2014-06-01
A variant of the topological twist, involving SL(2, ℤ) dualities and hence named topological duality twist, is introduced and explicitly applied to describe a U(1) N = 4 super Yang-Mills theory on a Kähler space with holomorphically space-dependent coupling. Three-dimensional duality walls and two-dimensional chiral theories naturally enter the formulation of the duality twisted theory. Appropriately generalized, this theory is relevant for the study of Euclidean D3-brane instantons in F-theory compactifications. Some of its properties and implications are discussed.
Conformal invariance and pion wave functions of nonleading twist
International Nuclear Information System (INIS)
Braun, V.M.; Filyanov, I.E.
1989-01-01
The restrictions are studied for the general structure of pion wave functions of twist 3 and twist 4 imposed by the conformal symmetry and the equations of motion. A systematic expansion of wave functions in the conformal spin is built and the first order corrections to asymptotic formulae are calculated by the QCD sum rule method. In particular, we have found a multiplicatively renormalizable contribution into the two-particle wave function of twist 4 which cannot be expanded in a finite set of Gegenbauer polynomials. 19 refs.; 5 figs
Design and development of wireless baby monitors
Jen, Yi-Kuo Eric
2008-01-01
The Philips DAP SCD510, SCD520, SCD530, and SCD540 1.8GHz/1.9GHz DECT Digital Wireless Baby Monitors are part of the next generation digital baby monitor products that emphasize on small form factor, innovative feature set, and cost effective bill of materials. New product features include wideband audio, ambient relative humidity measurement, and carbon monoxide detection. The objectives of this project are to design and develop these four baby monitor products and begin mass production for ...
Blossier, BenoÃ®t.; Brinet, Mariane; Guichon, Pierre; Morénas, Vincent; Pène, Olivier; Rodríguez-Quintero, Jose; Zafeiropoulos, Savvas
2015-06-01
We present a precise nonperturbative determination of the renormalization constants in the mass independent RI'-MOM scheme. The lattice implementation uses the Iwasaki gauge action and four degenerate dynamical twisted-mass fermions. The gauge configurations are provided by the ETM Collaboration. Renormalization constants for scalar, pseudoscalar, vector and axial operators, as well as the quark propagator renormalization, are computed at three different values of the lattice spacing, two volumes and several twisted-mass parameters. The method we developed allows for a precise cross-check of the running, thanks to the particular proper treatment of hypercubic artifacts. Results for the twist-2 operator O44 are also presented.
Sickle Cell Disease and Your Baby
... type of hemoglobin) from the other parent. Hemoglobin S-beta thalassemia. This condition is caused when a baby gets ... from one parent and a gene change for beta thalassemia from the other parent. How do you know ...
Benzocaine and Babies: Not a Good Mix
... Consumers Consumer Updates Benzocaine and Babies: Not a Good Mix Share Tweet Linkedin Pin it More sharing ... children are more at risk, it’s still a good idea to talk to your health care professional ...
Finding a Doctor for Your New Baby
... busy one. Along with considering baby names and buying a crib, choosing the right health care provider ... less extensively trained in children's health care. These feelings are largely unwarranted. The presence of PNPs in ...
Your Baby's Development: The Third Trimester
... fall off. You may see some of the leftover hair after your baby is born. Most of ... Categories: Family Health, Pregnancy and ChildbirthTags: Obstetrical, Pregnant Women, prenatal care October 1, 2009 Copyright © American Academy ...
Help Protect Babies from Whooping Cough
... Button Past Emails Help Protect Babies from Whooping Cough Language: English (US) Español (Spanish) Recommend on Facebook ... even knowing they have the disease. Understanding Whooping Cough Vaccines: DTaP and Tdap Two vaccines in the ...
Common Cold in Babies: Symptoms and Causes
... their coughs and sneezes, which increases your baby's risk of catching a cold. Time of year. Both children and adults are more susceptible to colds from fall to late spring. Complications Acute ear infection (otitis ...
Zika Virus: Protecting Pregnant Women and Babies
... Digital Press Kit Read the MMWR Science Clips Zika Virus Protecting Pregnant Women and Babies Language: English (US) ... Spanish) Recommend on Facebook Tweet Share Compartir Overview Zika virus infection (Zika) during pregnancy can cause damage to ...
How mothers keep their babies warm.
Bacon, C J; Bell, S A; Clulow, E E; Beattie, A B
1991-05-01
Details of room temperature, clothing, and bedding used by night and by day and in winter and in summer were recorded for 649 babies aged 8 to 26 weeks. Room temperature at night was significantly related to outside temperature and duration of heating. Total insulation was significantly related to outside temperature and to minimum room temperature, but there was wide variation in insulation at the same room temperature. High levels of insulation for a given room temperature were found particularly at night and in winter, and were associated with the use of thick or doubled duvets and with swaddling. At least half the babies threw off some or all of their bedding at night, and at least a quarter sweated. Younger mothers and mothers in the lower social groups put more bedclothes over their babies, and the latter also kept their rooms warmer. Many mothers kept their babies warmer during infections.
Your Baby's Development: The First Trimester
... how your baby develops during the first trimester. Path to well being Pregnancy begins when a man’s ... You’ll probably feel them starting in the middle of the second trimester. After the embryonic stage, ...
Pacifiers: Are They Good for Your Baby?
... chosen a favorite pacifier, keep a few identical backups on hand. Let your baby set the pace. ... in risk of sudden infant death syndrome. Cochrane Database of Systematic Reviews. http://dx.doi.org/10. ...
When Your Teen Is Having a Baby
... Feelings Expert Answers Q&A Movies & More for Teens Teens site Sitio para adolescentes Body Mind Sexual ... Videos for Educators Search English Español When Your Teen Is Having a Baby KidsHealth / For Parents / When ...
Mineral profile of Spanish commercial baby food.
Mir-Marqués, Alba; González-Masó, Anna; Cervera, M Luisa; de la Guardia, Miguel
2015-04-01
Commercial baby foods are an important part of the daily intake of babies from 6 to 12 months. The mineral profile of commercial baby foods in Spain was determined to establish levels of essential and non-essential elements, and their contribution to adequate intake (AI) and estimated average requirement (EAR). Thirty-five jars of commercial foods containing meat, fish, vegetables and fruit were obtained from the Spanish market and the mineral composition determined for 14 elements. In general, the baby foods analysed were sufficient for an adequate mineral intake, but contributions to AI and EAR for iron, zinc and calcium were very low (5-20%, 10-60% and 10-70%, respectively). This deficiency could be associated with growth problems or diseases in adulthood, and fortification of commercial products is recommended. Copyright © 2014 Elsevier Ltd. All rights reserved.
Feeding Tips For Your Baby with CHD
... best when fed more often and on a demand schedule. They tend to tire quickly during the ... your baby. Other Liquids Avoid giving your infant water, because water has no calories. You may give ...
Why lions roar like babies cry
Titze, Ingo
2012-11-01
When an angry lion roars, the sounds it emits can terrify anyone within earshot. But, as Ingo Titze explains, the properties of a lion's roar have some surprising similarities with those of a crying baby.
Healthy Family 2009: Bringing in Baby
... Navigation Bar Home Current Issue Past Issues Healthy Family 2009 Bringing in Baby Past Issues / Winter 2009 ... Down syndrome and other common genetic disorders, inherited family conditions, such as Duchenne muscular dystrophy, or disorders ...
A report from America: Baby M.
Rachels, James
1987-10-01
Rachels reviews the social and legal facts of the celebrated "Baby M" case, in which surrogate Mary Beth Whitehead attempted to keep the daughter she had borne under contract to William Stern. The first phase of the legal battle between the parents ended in March 1988, when New Jersey Superior Court Judge Harvey R. Sorkow upheld the validity of the surrogacy contract, terminated Whitehead's parental rights, and awarded custody of the child to Stern. Rachels comments on public reaction to "Baby M," on Sorkow's decision, and on the impact the case may have on legislative attempts to regulate surrogacy. He also uses the example of "Baby M," as well as that of California heart transplant patient "Baby Jesse," to discuss how the media sensationalize controversial issues.
Mermaid baby | Khan | SA Journal of Radiology
African Journals Online (AJOL)
Abstract. We were recently intrigued by a baby born at Kalafong Hospital with fused lower extremities resembling a mermaid, which caused us to search for the background and origin of this entity called sirenomelia.
Õnnetu saatusega Oliver Twist Polanski meelevallas / Andres Laasik
Laasik, Andres, 1960-2016
2005-01-01
Mängufilm Charles Dickensi romaani järgi "Oliver Twist" : stsenarist Ronald Harwood : režissöör Roman Polanski : nimiosas Barney Clark, Fagin - Ben Kingsley : Suurbritannia - Tšehhi - Prantsusmaa - Itaalia 2005
Polanski lavastas filmi "Oliver Twist" oma lastele / Andres Laasik
Laasik, Andres, 1960-2016
2005-01-01
Mängufilm "Oliver Twist" Charles Dickensi romaani ainetel esilinastus Prahas, kus toimusid ka filmivõtted. Tšehhi, Suurbritannia, Prantsusmaa ja Itaalia koostöös valminud filmi lavastas Roman Polanski
Twisted Masses and Enhanced Symmetries: the A&D Series
Orlando, Domenico
2012-01-01
We study new symmetries between A and D type quiver gauge theories with different numbers of colors. We realize these gauge theories with twisted masses via a brane construction that reproduces all the parameters of the Gauge/Bethe correspondence.
A Novel Wavelength Demodulation Method Using Twisted High Birefringence Fiber
International Nuclear Information System (INIS)
Niu, L Y; Yang, H Y; Wu, F; Li, Z Q
2006-01-01
The mathematical model of twisted high birefringence fiber was established through theoretical analysis. A novel FBG wavelength demodulation method was put forward, by using the twisted high birefringence fiber. The numerical simulation and the experiments were carried out to the system. The standard cosine relationship was observed between the output intensity of polarization analyzer and the twist angle for the signal light with different wavelengths. When the twist angle of the high birefringence fiber is 0 and π/2, the output intensity ratio of the system presents the linear relationship with the wavelength approximately. The experiment shows that system is in agreement very well with theoretical analysis to demodulate guasi-linearly FBG wavelength shift in range of about 10 nm
Active-Twist Rotor Control Applications for UAVs
National Research Council Canada - National Science Library
Wilbur, Matthew L; Wilkie, W. K
2004-01-01
The current state-of-the-art in active-twist rotor control is discussed using representative examples from analytical and experimental studies, and the application to rotary-wing UAVs is considered...
Determination of Elastic Twist in Horizontal Axis Wind Turbines (HAWTs)
Energy Technology Data Exchange (ETDEWEB)
Stoddard, F.; Nelson, V.; Starcher, K.; Andrews, B.
2006-06-01
This report presents the results of a project at the Alternative Energy Institute (AEI) which measured and calculated the elastic twist of three representative composite horizontal-axis blades: Carter 300, Gougeon ESI 54, and UTRC 8 kW.
PIXE analysis by baby cyclotron
International Nuclear Information System (INIS)
Yoshida, Hyogo; Tanaka, Teruaki; Ito, Takashi; Toda, Yohjiro; Wakasa, Hideichiro
1988-01-01
The Japan Steel Works, Ltd. has been supplying a very small sized cyclotron (Baby Cyclotron) to hospitals and research facilities. The cyclotron is designed to produce short-lived radioisotopes for medical use. In the present study, this cyclotron is modified so that it can serve for PIXE analysis. The PIXE (particle induced X-ray emission) technique has the following features: (1) Down to 1 ng of trace material in a sample (mg - μg) can be detected, (2) An analysis run is completed in one to ten minutes, permitting economical analysis for a large number of samples, (3) Several elements can be analyzed simultaneously, with an almost constant sensitivity for a variety of elements ranging from aluminum to heavy metals, (4) Analysis can be performed nondestructively without a chemical process, and (5) The use of microbeam can provide data on the distribution of elements with a resolution of several μm. Software for analysis is developed to allow the modified equipment to perform peak search, background fitting, and identification and determination of peaks. A study is now being conducted to examine the performance of the equipment for PIXE analysis of thin samples. Satisfactory results have been obtained. The analysis time, excluding the background correction, is 5-10 min. (Nogami, K.)
Qadeer, Imrana
2010-01-01
New legislation can be oppressive for a significant population depending upon the politics of its drafters. The current upsurge of the surrogacy trade in India, and the label of a "win-win" situation that it has acquired, points towards an unfettered commercialisation of assisted reproductive technology and the practice of surrogacy that is blinding its middle class users as well as providers, policy makers and law makers, and charging an imagination that is already caught up in spiralling consumerism. This paper analyses the Draft Assisted Reproductive Technology (Regulation) Bill and Rules, 2008, in the Indian socioeconomic context. It identifies the interests of the affected women, and examines the contradictions of the proposed Bill with their interests, as well as with current health and population policies, confining itself to the handling of surrogacy and not the entire content of the Bill. The bases of the analytical perspective used are: the context of poverty and the health needs of the Indian population; the need to locate surrogacy services within the overall public health service context and its epidemiological basis; the need to restrain direct human experimentation for the advancement of any technology; the use of safer methods; and, finally, the rights of surrogate mothers and their babies, in India, as opposed to the compulsion or dynamics of the medical market and reproductive tourism.
Safe Sleep for Babies PSA (:60)
Centers for Disease Control (CDC) Podcasts
2018-01-09
This 60 second public service announcement is based on the January 2018 CDC Vital Signs report. Every year, there are about 3,500 sleep-related deaths among U.S. babies. Learn how to create a safe sleep environment for babies. Created: 1/9/2018 by Centers for Disease Control and Prevention (CDC). Date Released: 1/9/2018.
Disposable baby wipes: efficacy and skin mildness.
Odio, M; Streicher-Scott, J; Hansen, R C
2001-04-01
The results of a series of four clinical studies demonstrated that disposable baby wipes were milder to the skin than use of a cotton washcloth and water, recognized as a "gold standard" for skin mildness. Importantly, the baby wipes caused no significant change from the baseline value in any of the skin parameters examined. This observation verified that the test wipes are minimally disruptive to the epidermal barrier and thus suitable for use on intact or compromised, irritated skin.
Resuscitating the Baby after Shoulder Dystocia
Menticoglou, Savas; Schneider, Carol
2016-01-01
Background. To propose hypovolemic shock as a possible explanation for the failure to resuscitate some babies after shoulder dystocia and to suggest a change in clinical practice. Case Presentation. Two cases are presented in which severe shoulder dystocia was resolved within five minutes. Both babies were born without a heartbeat. Despite standard resuscitation by expert neonatologists, no heartbeat was obtained until volume resuscitation was started, at 25 minutes in the first case and 11 m...
Energy Spectrum and Quantum Hall Effect in Twisted Bilayer Graphene
Moon, Pilkyung; Koshino, Mikito
2012-01-01
We investigate the electronic spectra and quantum Hall effect in twisted bilayer graphenes with various rotation angles under magnetic fields, using a model rigorously including the interlayer interaction. We describe the spectral evolution from discrete Landau levels in the weak field regime to the fractal band structure in the strong field regime, and estimate the quantized Hall conductivity for each single gap. In weak magnetic fields, the low-energy conduction band of the twisted bilayer ...
Active-Twist Rotor Control Applications for UAVs
Wilbur, Matthew L.; Wilkie, W. Keats
2004-01-01
The current state-of-the-art in active-twist rotor control is discussed using representative examples from analytical and experimental studies, and the application to rotary-wing UAVs is considered. Topics include vibration and noise reduction, rotor performance improvement, active blade tracking, stability augmentation, and rotor blade de-icing. A review of the current status of piezoelectric fiber composite actuator technology, the class of piezoelectric actuators implemented in active-twist rotor systems, is included.
Polarisation of microwave emission from reconnecting twisted coronal loops
Gordovskyy, M.; Browning, P. K.; Kontar, E. P.
2017-08-01
Context. Magnetic reconnection and particle acceleration due to the kink instability in twisted coronal loops can be a viable scenario for confined solar flares. Detailed investigation of this phenomenon requires reliable methods for observational detection of magnetic twist in solar flares, which may not be possible solely through extreme UV and soft X-ray thermal emission. Polarisation of microwave emission in flaring loops can be used as one of the detection criteria. Aims: The aim of this study is to investigate the effect of magnetic twist in flaring coronal loops on the polarisation of gyro-synchrotron microwave (GSMW) emission, and determine whether it could provide a means for magnetic twist detection. Methods: We consider time-dependent magnetohydrodynamic and test-particle models developed using the LARE3D and GCA codes to investigate twisted coronal loops that relax after kink instability. Synthetic GSMW emission maps (I and V Stokes components) are calculated using GX simulator. Results: It is found that flaring twisted coronal loops produce GSMW radiation with a gradient of circular polarisation across the loop. However, these patterns may be visible only for a relatively short period of time owing to fast magnetic reconfiguration after the instability. Their visibility also depends on the orientation and position of the loop on the solar disk. Typically, it would be difficult to see these characteristic polarisation patterns in a twisted loop seen from the top (I.e. close to the centre of the solar disk), but easier in a twisted loop seen from the side (I.e. observed very close to the limb).
Wear characteristics of UHMW polyethylene by twist method
Chișiu, G.; Popescu, A. M.; Tudor, A.; Petrescu, A. M.; Stoica, G. F.; Subhi, K. A.
2018-01-01
A wear test of the twist movement was performed as a new method to estimate the in vivo wear behavior of an acetabular cup material for total knee replacements. A series of UHMWPE samples was used to evaluate the dynamic coefficient of friction in twist movement in contact with steel. The experimental data were conducted to validate the related theoretical model developed in the present study.
Study of twist boundaries in aluminium. Structure and intergranular diffusion
International Nuclear Information System (INIS)
Lemuet, Daniel
1981-01-01
This research thesis addresses the study of grain boundaries in oriented crystals, and more particularly the systematic calculation of intergranular structures and energies of twist boundaries of <001> axis in aluminium, the determination of intergranular diffusion coefficients of zinc in a set of twist bi-crystals of same axis encompassing a whole range of disorientations, and the search for a correlation between these experimental results and calculated structures
Traditional foods vs. manufactured baby foods.
Ferguson, Elaine L; Darmon, Nicole
2007-01-01
The provision of nutrient-dense complementary foods is essential to ensure an infant's nutrient requirements are met. Yet often, relative to recommendations, traditional complementary foods have low levels of nutrients, suggesting a role, for fortified manufactured baby foods, in ensuring dietary adequacy. In this review, the potential benefits and safety of using fortified manufactured baby foods versus traditional foods alone are evaluated based on evidence from food composition data, diet modeling and intervention studies. Results from the food composition data and diet modeling suggest that ensuring a nutritionally adequate complementary feeding diet based on traditional foods alone is difficult. Conversely, except for biochemical iron status, intervention trials do not show consistent benefits, for growth or biochemical zinc or riboflavin status, with the use of fortified manufactured baby foods versus traditional foods alone. The safety of manufactured baby foods will depend on food preparation practices and the presence of effective governmental regulatory infrastructures. Hence, in environments where fortified manufactured baby foods are expensive, unavailable or where there is an absence of effective governmental regulatory infrastructures, the use of traditional foods is advised. Conversely, where affordable manufactured baby foods are available, marketed safely and fortified appropriately, their use is likely to result in improved nutrient intakes and infant biochemical iron status. In all environments, the promotion of breastfeeding, active feeding and high levels of hygiene is essential to ensure optimal nutritional status.
Skyrmionic vortex lattices in coherently coupled three-component Bose-Einstein condensates
Orlova, Natalia V.; Kuopanportti, Pekko; Milošević, Milorad V.
2016-08-01
We show numerically that a harmonically trapped and coherently Rabi-coupled three-component Bose-Einstein condensate can host unconventional vortex lattices in its rotating ground state. The discovered lattices incorporate square and zig-zag patterns, vortex dimers and chains, and doubly quantized vortices, and they can be quantitatively classified in terms of a skyrmionic topological index, which takes into account the multicomponent nature of the system. The exotic ground-state lattices arise due to the intricate interplay of the repulsive density-density interactions and the Rabi couplings as well as the ubiquitous phase frustration between the components. In the frustrated state, domain walls in the relative phases can persist between some components even at strong Rabi coupling, while vanishing between others. Consequently, in this limit the three-component condensate effectively approaches a two-component condensate with only density-density interactions. At intermediate Rabi coupling strengths, however, we face unique vortex physics that occurs neither in the two-component counterpart nor in the purely density-density-coupled three-component system.
Skyrmions, Skyrme stars and black holes with Skyrme hair in five spacetime dimension
Brihaye, Yves; Herdeiro, Carlos; Radu, Eugen; Tchrakian, D. H.
2017-11-01
We consider a class of generalizations of the Skyrme model to five spacetime dimensions ( d = 5), which is defined in terms of an O(5) sigma model. A special ansatz for the Skyrme field allows angular momentum to be present and equations of motion with a radial dependence only. Using it, we obtain: 1) everywhere regular solutions describing localised energy lumps ( Skyrmions); 2) Self-gravitating, asymptotically flat, everywhere non-singular solitonic solutions ( Skyrme stars), upon minimally coupling the model to Einstein's gravity; 3) both static and spinning black holes with Skyrme hair, the latter with rotation in two orthogonal planes, with both angular momenta of equal magnitude. In the absence of gravity we present an analytic solution that satisfies a BPS-type bound and explore numerically some of the non-BPS solutions. In the presence of gravity, we contrast the solutions to this model with solutions to a complex scalar field model, namely boson stars and black holes with synchronised hair. Remarkably, even though the two models present key differences, and in particular the Skyrme model allows static hairy black holes, when introducing rotation, the synchronisation condition becomes mandatory, providing further evidence for its generality in obtaining rotating hairy black holes.
Twisting short dsDNA with applied tension
Zoli, Marco
2018-02-01
The twisting deformation of mechanically stretched DNA molecules is studied by a coarse grained Hamiltonian model incorporating the fundamental interactions that stabilize the double helix and accounting for the radial and angular base pair fluctuations. The latter are all the more important at short length scales in which DNA fragments maintain an intrinsic flexibility. The presented computational method simulates a broad ensemble of possible molecule conformations characterized by a specific average twist and determines the energetically most convenient helical twist by free energy minimization. As this is done for any external load, the method yields the characteristic twist-stretch profile of the molecule and also computes the changes in the macroscopic helix parameters i.e. average diameter and rise distance. It is predicted that short molecules under stretching should first over-twist and then untwist by increasing the external load. Moreover, applying a constant load and simulating a torsional strain which over-twists the helix, it is found that the average helix diameter shrinks while the molecule elongates, in agreement with the experimental trend observed in kilo-base long sequences. The quantitative relation between percent relative elongation and superhelical density at fixed load is derived. The proposed theoretical model and computational method offer a general approach to characterize specific DNA fragments and predict their macroscopic elastic response as a function of the effective potential parameters of the mesoscopic Hamiltonian.
Twist decomposition of Drell-Yan structure functions: phenomenological implications
Energy Technology Data Exchange (ETDEWEB)
Brzemiński, Dawid [Institute of Physics, Jagiellonian University,S. Łojasiewicza 11, 30-348 Kraków (Poland); Cavendish Laboratory, University of Cambridge,19 J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Motyka, Leszek; Sadzikowski, Mariusz; Stebel, Tomasz [Institute of Physics, Jagiellonian University,S. Łojasiewicza 11, 30-348 Kraków (Poland)
2017-01-02
The forward Drell-Yan process in pp scattering at the LHC at √S=14 TeV is considered. We analyze the Drell-Yan structure functions assuming the dominance of a Compton-like emission of a virtual photon from a fast quark scattering off the small x gluons. The color dipole framework is applied to perform quantitatively the twist decomposition of all the Drell-Yan structure functions. Two models of the color dipole scattering are applied: the Golec-Biernat-Wüsthoff model and the dipole cross section obtained from the Balitsky-Fadin-Kuraev-Lipatov evolution equation. The two models have essentially different higher twist content and the gluon transverse momentum distribution and lead to different significant effects beyond the collinear leading twist description. It is found that the gluon transverse momentum effects are significant in the Drell-Yan structure functions for all Drell-Yan pair masses M, and the higher twist effects become important for M≲10 GeV. It is found that the structure function W{sub TT} related to the A{sub 2} angular coefficient and the Lam-Tung observable A{sub 0}−A{sub 2} are particularly sensitive to the gluon k{sub T} effects and to the higher twist effects. A procedure is suggested how to disentangle the higher twist effects from the gluon transverse momentum effects.
How the embryonic chick brain twists
Guo, Qiaohang; Dai, Eric; Forsch, Nickolas; Taber, Larry A.
2016-01-01
During early development, the tubular embryonic chick brain undergoes a combination of progressive ventral bending and rightward torsion, one of the earliest organ-level left–right asymmetry events in development. Existing evidence suggests that bending is caused by differential growth, but the mechanism for the predominantly rightward torsion of the embryonic brain tube remains poorly understood. Here, we show through a combination of in vitro experiments, a physical model of the embryonic morphology and mechanics analysis that the vitelline membrane (VM) exerts an external load on the brain that drives torsion. Our theoretical analysis showed that the force is of the order of 10 micronewtons. We also designed an experiment to use fluid surface tension to replace the mechanical role of the VM, and the estimated magnitude of the force owing to surface tension was shown to be consistent with the above theoretical analysis. We further discovered that the asymmetry of the looping heart determines the chirality of the twisted brain via physical mechanisms, demonstrating the mechanical transfer of left–right asymmetry between organs. Our experiments also implied that brain flexure is a necessary condition for torsion. Our work clarifies the mechanical origin of torsion and the development of left–right asymmetry in the early embryonic brain. PMID:28334695
Twisted conformal field theories and Morita equivalence
Energy Technology Data Exchange (ETDEWEB)
Marotta, Vincenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' and INFN, Sezione di Napoli, Compl. universitario M. Sant' Angelo, Via Cinthia, 80126 Napoli (Italy); Naddeo, Adele [CNISM, Unita di Ricerca di Salerno and Dipartimento di Fisica ' E.R. Caianiello' , Universita degli Studi di Salerno, Via Salvador Allende, 84081 Baronissi (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' , Compl. universitario M. Sant' Angelo, Via Cinthia, 80126 Napoli (Italy)], E-mail: adelenaddeo@yahoo.it
2009-04-01
The Morita equivalence for field theories on noncommutative two-tori is analysed in detail for rational values of the noncommutativity parameter {theta} (in appropriate units): an isomorphism is established between an Abelian noncommutative field theory (NCFT) and a non-Abelian theory of twisted fields on ordinary space. We focus on a particular conformal field theory (CFT), the one obtained by means of the m-reduction procedure [V. Marotta, J. Phys. A 26 (1993) 3481; V. Marotta, Mod. Phys. Lett. A 13 (1998) 853; V. Marotta, Nucl. Phys. B 527 (1998) 717; V. Marotta, A. Sciarrino, Mod. Phys. Lett. A 13 (1998) 2863], and show that it is the Morita equivalent of a NCFT. Finally, the whole m-reduction procedure is shown to be the image in the ordinary space of the Morita duality. An application to the physics of a quantum Hall fluid at Jain fillings {nu}=m/(2pm+1) is explicitly discussed in order to further elucidate such a correspondence and to clarify its role in the physics of strongly correlated systems. A new picture emerges, which is very different from the existing relationships between noncommutativity and many body systems [A.P. Polychronakos, arXiv: 0706.1095].
The Latest Twists in Chromatin Remodeling.
Blossey, Ralf; Schiessel, Helmut
2018-01-05
In its most restrictive interpretation, the notion of chromatin remodeling refers to the action of chromatin-remodeling enzymes on nucleosomes with the aim of displacing and removing them from the chromatin fiber (the effective polymer formed by a DNA molecule and proteins). This local modification of the fiber structure can have consequences for the initiation and repression of the transcription process, and when the remodeling process spreads along the fiber, it also results in long-range effects essential for fiber condensation. There are three regulatory levels of relevance that can be distinguished for this process: the intrinsic sequence preference of the histone octamer, which rules the positioning of the nucleosome along the DNA, notably in relation to the genetic information coded in DNA; the recognition or selection of nucleosomal substrates by remodeling complexes; and, finally, the motor action on the nucleosome exerted by the chromatin remodeler. Recent work has been able to provide crucial insights at each of these three levels that add new twists to this exciting and unfinished story, which we highlight in this perspective. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Baby boom generation at the retirement onset
Directory of Open Access Journals (Sweden)
Stojilković Jelena
2010-01-01
Full Text Available Sudden increase in the number of live births after the Second World War due to an increase in fertility rates has led to the formation of cohorts with specific characteristics or baby boom generation. This generation is unique in the history of the demographic phenomenon that has affected and affects the functioning of many segments of society. The aim of this paper is to assess structure of baby boomers who are few years away from retirement, using demographic data. Impact of baby boomer age structure of current and future retirees is described with a graphical display of current and projected age pyramid of baby boomers. Demographic pattern that women live longer than men is evident in the projected pyramid. In addition, the number of baby boomers will lead to a "younger" old population. The imbalance in the number of men and women pensioners, as well as older cohorts of women and female baby boomers was analyzed. As a result, an increasing trend of women's age pensioners who are members of the baby boom generation was clearly observed, which is opposite to the older cohort of women who often were family pensioners. Different circumstances and conditions in which female boomers lived and worked will form a new "pension model" because they will gain their benefits as well as men, for the first time in significant number, unlike their mothers, which gained the right to retire after they become widows. Number of women age pensioners is getting greater comparing to men, as the result of changes in the economic activities of women in the last half of the 20th century. When baby boomers retire and exit the working population, this will create a vacuum, because the numerically smaller generations will enter working population, while the sudden and very shortly, the number of population older than 60 or 65 will increase, most of them will likely to acquire the right to a pension. It is undeniable that baby boomers had impact on demographic structure
International Nuclear Information System (INIS)
Kingler, J.
1990-01-01
A Lund type Monte Carlo program (LUCIFER) is used to describe in perturbative QCD the pointlike component of the photon interacting on a hydrogen target. Kinematical and topological variables are developed to enhance higher twist events on the lowest order minimum twist background. The emphasis is laid on π ± , K ± higher twist mesons. (orig.)
Breech Babies: What Can I Do If My Baby Is Breech?
... and protects the baby. An abnormal fetal heart Premature rupture of the membranes. Twins or other multiples pregnancy. ECV usually is ... ECV are small, but include: Early onset labor. Premature rupture of the membranes. Minor blood loss for either the baby or ...
What is my Baby Like? Representations Concerning the Baby in the Third Trimester of Pregnancy
Directory of Open Access Journals (Sweden)
Marta Pedreira
2015-11-01
Full Text Available AimTo investigate if during the third trimester of pregnancy fantasies emerge in the baby representations based on the information that pregnant women have on their real babies through ultrasound techniques.MethodA qualitative, descriptive and exploratory research based on a sample of 30 pregnant Portuguese women, whose average age is 32 years old, was developed. A socio-demographic questionnaire and a semi-directive interview entitled "Interview of Maternal Representations During Pregnancy – Revised Version" (IRMAG-R, Ammaniti & Tambelli, 2010 were employed.ResultsBaby representations are immersed in a fantasy dimension, which means that the imaginary baby is quite present in this phase of pregnancy. Pregnant women mainly attribute psychological characteristics to the babies, rather than physical characteristics. Regardless of the type of characteristics analysed, the preference for these characteristics emerges based on their wishes. Secondly, characteristics of the parents may also emerge. Fetal movements and information from ultrasound have no significant influence on the characterization of the baby.ConclusionDespite the development of ultrasound techniques, the imaginary baby defines parents representations about the baby on the third trimester of pregnancy. Consequently, a new understanding of how pregnant women experience the transition to the postnatal phase has to be considered.
Universal corner entanglement from twist operators
Energy Technology Data Exchange (ETDEWEB)
Bueno, Pablo [Instituto de Física Teórica UAM/CSIC, C/Nicolás Cabrera, 13-15, C.University Cantoblanco, 28049 Madrid (Spain); Myers, Robert C.; Witczak-Krempa, William [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, ON N2L 2Y5 (Canada)
2015-09-15
The entanglement entropy in three-dimensional conformal field theories (CFTs) receives a logarithmic contribution characterized by a regulator-independent function a(θ) when the entangling surface contains a sharp corner with opening angle θ. In the limit of a smooth surface (θ→π), this corner contribution vanishes as a(θ)=σ (θ−π){sup 2}. In http://arxiv.org/abs/1505.04804, we provided evidence for the conjecture that for any d=3 CFT, this corner coefficient σ is determined by C{sub T}, the coefficient appearing in the two-point function of the stress tensor. Here, we argue that this is an instance of a much more general relation connecting the analogous corner coefficient σ{sub n} appearing in the nth Rényi entropy and the scaling dimension h{sub n} of the corresponding twist operator. In particular, we find the simple relation h{sub n}/σ{sub n}=(n−1)π. We show how it reduces to our previous result as n→1, and explicitly check its validity for free scalars and fermions. With this new relation, we show that as n→0, σ{sub n} yields the coefficient of the thermal entropy, c{sub S}. We also reveal a surprising duality relating the corner coefficients of the scalar and the fermion. Further, we use our result to predict σ{sub n} for holographic CFTs dual to four-dimensional Einstein gravity. Our findings generalize to other dimensions, and we emphasize the connection to the interval Rényi entropies of d=2 CFTs.
Phosphorylation of basic helix-loop-helix transcription factor Twist in development and disease.
Xue, Gongda; Hemmings, Brian A
2012-02-01
The transcription factor Twist plays vital roles during embryonic development through regulating/controlling cell migration. However, postnatally, in normal physiological settings, Twist is either not expressed or inactivated. Increasing evidence shows a strong correlation between Twist reactivation and both cancer progression and malignancy, where the transcriptional activities of Twist support cancer cells to disseminate from primary tumours and subsequently establish a secondary tumour growth in distant organs. However, it is largely unclear how this signalling programme is reactivated or what signalling pathways regulate its activity. The present review discusses recent advances in Twist regulation and activity, with a focus on phosphorylation-dependent Twist activity, potential upstream kinases and the contribution of these factors in transducing biological signals from upstream signalling complexes. The recent advances in these areas have shed new light on how phosphorylation-dependent regulation of the Twist proteins promotes or suppresses Twist activity, leading to differential regulation of Twist transcriptional targets and thereby influencing cell fate.
Czech Academy of Sciences Publication Activity Database
Gayles, J.; Freimuth, F.; Schena, T.; Lani, G.; Mavropoulos, P.; Duine, R.A.; Blügel, S.; Sinova, Jairo; Mokrousov, Y.
2016-01-01
Roč. 115, č. 3 (2016), 1-6, č. článku 036602. ISSN 0031-9007 Institutional support: RVO:68378271 Keywords : topological Hall effect * skyrmions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 8.462, year: 2016
Baby factories taint surrogacy in Nigeria.
Makinde, Olusesan Ayodeji; Makinde, Olufunmbi Olukemi; Olaleye, Olalekan; Brown, Brandon; Odimegwu, Clifford O
2016-01-01
The practice of reproductive medicine in Nigeria is facing new challenges with the proliferation of 'baby factories'. Baby factories are buildings, hospitals or orphanages that have been converted into places for young girls and women to give birth to children for sale on the black market, often to infertile couples, or into trafficking rings. This practice illegally provides outcomes (children) similar to surrogacy. While surrogacy has not been well accepted in this environment, the proliferation of baby factories further threatens its acceptance. The involvement of medical and allied health workers in the operation of baby factories raises ethical concerns. The lack of a properly defined legal framework and code of practice for surrogacy makes it difficult to prosecute baby factory owners, especially when they are health workers claiming to be providing services to clients. In this environment, surrogacy and other assisted reproductive techniques urgently require regulation in order to define when ethico-legal lines have been crossed in providing surrogacy or surrogacy-like services. Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Phthalates in baby skin care products.
Lampel, Heather P; Jacob, Sharon E
2011-01-01
The systemic toxicity of phthalates has been extensively reported. Although rarely sensitizing, phthalates have been implicated in promoting the development of both atopy and contact dermatitis in animal models. Dermal absorption of phthalates may contribute to overall chemical burden. Infants may be particularly susceptible to chemical exposures. Baby skin care products may be a significant source of phthalate exposure. We measured the phthalate content of 30 skin care products intended for babies and children. Nineteen leave-on and 11 wash-off baby skin care products were analyzed for 17 unique phthalates by an independent laboratory using standard gas chromatographic mass spectrometry. Of 30 products tested, four had phthalate levels above the reporting limit (0.1-0.5 ppm); of these, only one had levels above 1 ppm (44 ppm). There was no statistical significance of phthalate detection in leave-on versus wash-off products (p = .578). The majority (26 of 30) of the baby skin care products analyzed did not have detectable phthalate levels. Four products had detectable phthalate levels. In baby skin care products, levels of the 17 phthalates tested are low overall, but occasional products may contain higher phthalate levels. Monitoring products to ensure safety standards are met may be warranted.
Reducing the risk of baby falls in maternity units.
Janiszewski, Helen
During a 12-month period there were 17 baby falls on the maternity wards at Nottingham University Hospitals Trust; two of the babies who fell were injured. By collecting information about the baby falls and how they happened, we were able to compile a guideline for both preventing and managing baby falls. This formed part of the trust's patient safety programme. We then piloted and implemented risk-prevention strategies for baby falls. These involved a risk assessment to identify women needing closer observation and the installation of bedside cots. These strategies brought about a marked reduction of baby falls and are now being established across all the maternity units across the trust.
Mothers' use of and attitudes to BabyCheck.
Thomson, Hilary; Ross, Sue; Wilson, Philip; McConnachie, Alex; Watson, Richard
2002-01-01
A copy of BabyCheck was sent to 497 mothers shortly after the birth of their baby. Six months later they were sent a questionnaire asking about their use of and attitudes to, BabyCheck. Questionnaires were returned by 323 (65%) mothers; 215 (67%) of them reported reading BabyCheck, the majority found it easy to understand (74%) and agreed with the advice (67%). Eighty-four (26%) of the mothers who returned the questionnaires reported using BabyCheck when their baby was ill; of these, 71% agre...
Comments on twisted indices in 3d supersymmetric gauge theories
Energy Technology Data Exchange (ETDEWEB)
Closset, Cyril [Simons Center for Geometry and PhysicsState University of New York, Stony Brook, NY 11794 (United States); Kim, Heeyeon [Perimeter Institute for Theoretical Physics31 Caroline Street North, Waterloo, N2L 2Y5, Ontario (Canada)
2016-08-09
We study three-dimensional N=2 supersymmetric gauge theories on Σ{sub g}×S{sup 1} with a topological twist along Σ{sub g}, a genus-g Riemann surface. The twisted supersymmetric index at genus g and the correlation functions of half-BPS loop operators on S{sup 1} can be computed exactly by supersymmetric localization. For g=1, this gives a simple UV computation of the 3d Witten index. Twisted indices provide us with a clean derivation of the quantum algebra of supersymmetric Wilson loops, for any Yang-Mills-Chern-Simons-matter theory, in terms of the associated Bethe equations for the theory on ℝ{sup 2}×S{sup 1}. This also provides a powerful and simple tool to study 3d N=2 Seiberg dualities. Finally, we study A- and B-twisted indices for N=4 supersymmetric gauge theories, which turns out to be very useful for quantitative studies of three-dimensional mirror symmetry. We also briefly comment on a relation between the S{sup 2}×S{sup 1} twisted indices and the Hilbert series of N=4 moduli spaces.
Terminal twist-induced writhe of DNA with intrinsic curvature.
Hu, Kai
2007-04-01
Supercoiling of a closed circular DNA rod may result from an application of terminal twist to the DNA rod by cutting the rod, rotating one of the cut faces as the other being fixed and then sealing the cut. According to White's formula, DNA supercoiling is probably accompanied by a writhe of the DNA axis. Deduced from the elastic rod model for DNA structure, an intrinsically straight closed circular DNA rod does not writhe as subject to a terminal twist, until the number of rotation exceeds a rod-dependent threshold. By contrast, a closed circular DNA rod with intrinsic curvature writhes instantly as subject to a terminal twist. This noteworthy character in fact belongs to many intrinsically curved DNA rods. By solving the dynamic equations, the linearization of the Euler-Lagrange equations governing intrinsically curved DNA rods, this paper shows that almost every clamped-end intrinsically curved DNA rod writhes instantly when subject to a terminal twist (clamped-end DNA rods include closed circular DNA rods and topological domains of open DNA rods). In terms of physical quantities, the exceptions are identified with points in R(6) whose projections onto R(5) (through ignoring the total energy density of a rod) form a subset of a quadratic hypersurface. This paper also suggests that the terminal twist induced writhe is due to the elasticity and the clamped-end boundary conditions of the DNA rods.
Finite element and analytical models for twisted and coiled actuator
Tang, Xintian; Liu, Yingxiang; Li, Kai; Chen, Weishan; Zhao, Jianguo
2018-01-01
Twisted and coiled actuator (TCA) is a class of recently discovered artificial muscle, which is usually made by twisting and coiling polymer fibers into spring-like structures. It has been widely studied since discovery due to its impressive output characteristics and bright prospects. However, its mathematical models describing the actuation in response to the temperature are still not fully developed. It is known that the large tensile stroke is resulted from the untwisting of the twisted fiber when heated. Thus, the recovered torque during untwisting is a key parameter in the mathematical model. This paper presents a simplified model for the recovered torque of TCA. Finite element method is used for evaluating the thermal stress of the twisted fiber. Based on the results of the finite element analyses, the constitutive equations of twisted fibers are simplified to develop an analytic model of the recovered torque. Finally, the model of the recovered torque is used to predict the deformation of TCA under varying temperatures and validated against experimental results. This work will enhance our understanding of the deformation mechanism of TCAs, which will pave the way for the closed-loop position control.
The Twist Tensor Nuclear Norm for Video Completion.
Hu, Wenrui; Tao, Dacheng; Zhang, Wensheng; Xie, Yuan; Yang, Yehui
2017-12-01
In this paper, we propose a new low-rank tensor model based on the circulant algebra, namely, twist tensor nuclear norm (t-TNN). The twist tensor denotes a three-way tensor representation to laterally store 2-D data slices in order. On one hand, t-TNN convexly relaxes the tensor multirank of the twist tensor in the Fourier domain, which allows an efficient computation using fast Fourier transform. On the other, t-TNN is equal to the nuclear norm of block circulant matricization of the twist tensor in the original domain, which extends the traditional matrix nuclear norm in a block circulant way. We test the t-TNN model on a video completion application that aims to fill missing values and the experiment results validate its effectiveness, especially when dealing with video recorded by a nonstationary panning camera. The block circulant matricization of the twist tensor can be transformed into a circulant block representation with nuclear norm invariance. This representation, after transformation, exploits the horizontal translation relationship between the frames in a video, and endows the t-TNN model with a more powerful ability to reconstruct panning videos than the existing state-of-the-art low-rank models.
Helping Babies Breathe implementation in Zanzibar, Tanzania.
Wilson, Gina Marie; Ame, Ame Masemo; Khatib, Maimuna Mohamed; Rende, Elizabeth K; Hartman, Ann Michelle; Blood-Siegfried, Jane
2017-08-01
To assess the efficacy and feasibility of implementing Helping Babies Breathe, a neonatal resuscitation programme for resource-limited environments. This quality improvement project focused on training midwives on Helping Babies Breathe to address high rates of neonatal mortality secondary to birth asphyxia. The convenience sample was 33 midwives in Zanzibar, Tanzania. The train-the-trainer strategy with repeated measures design was used to assess knowledge and skills at 3 time points. Observations were completed during "real-time" deliveries, and a focused interview generated feedback regarding satisfaction and sustainability. Knowledge scores and resuscitation skills significantly improved and were sustained, P < .05. Of the 62 birth observations, 19% needed intervention. All were appropriately resuscitated and survived. Results indicate that participants retained knowledge and skills and used them in clinical practice. Observations demonstrated that participants took appropriate actions when presented with a baby who was not breathing. © 2017 John Wiley & Sons Australia, Ltd.
VTR module: weaning foods for baby.
1993-01-01
Weaning should start when the baby turns 4 months old. At this stage (4 to 6 months), milk is no longer enough. Parents should introduce new foods which can meet the fast-increasing nutrition needs of the child. Among the latest materials produced by the Video Radio Production Division of the Nutrition Center of the Philippines is a VTR training module entitled "Karagdagang Pagkain ni Baby" (Weaning Foods for Baby), designed to strengthen this important aspect of child care. Specifically, the module seeks to encourage parents to introduce foods in addition to breastmilk to their 4 to 6 month old children and to start giving them "complete" meals from 6 months onward. It provides suggestions on the kinds of foods or food combinations to give to the baby and encourages home food production (backyard gardening, poultry-raising etc) to supply food requirements of growing children. Contents of the module include how-to's on weaning food preparation (mashing, straining, flaking, chopping, scraping, etc), prescriptions on the kinds and amounts of foods for babies; and food combinations (porridge or rice and a viand from the 3 basic food groups: energy-giving, body building and regulating). For instance, at 4 months old, the baby may be given lugao (porridge), soup and fruits; at 5 months, eggs, vegetables and beans; at 6 months, fish/meat, oil or gata (coconut oil). With a running time of 18 minutes, the module uses computer graphics to highlight food items, recommended amounts, and age group requirements in the text, and applies digital multi-effects to ensure smooth traditions. full text
Should babies be watching television and DVDs?
Wartella, Ellen A; Lauricella, Alexis R
2012-06-01
Should babies be watching television and DVDs? This is a reasonable question to ask but a difficult one to answer. This article reviews the theories and related research to examine what is known about infant media use. The review provides evidence both for and against each theory. The importance of infants learning how to watch and learn from screen media presentations is indicated and the new world of media to which babies are exposed is discussed. Copyright © 2012 Elsevier Inc. All rights reserved.
Three-dimensional mechanical metamaterials with a twist.
Frenzel, Tobias; Kadic, Muamer; Wegener, Martin
2017-11-24
Rationally designed artificial materials enable mechanical properties that are inaccessible with ordinary materials. Pushing on an ordinary linearly elastic bar can cause it to be deformed in many ways. However, a twist, the counterpart of optical activity in the static case, is strictly zero. The unavailability of this degree of freedom hinders applications in terms of mode conversion and the realization of advanced mechanical designs using coordinate transformations. Here, we aim at realizing microstructured three-dimensional elastic chiral mechanical metamaterials that overcome this limitation. On overall millimeter-sized samples, we measure twists per axial strain exceeding 2°/%. Scaling up the number of unit cells for fixed sample dimensions, the twist is robust due to metamaterial stiffening, indicating a characteristic length scale and bringing the aforementioned applications into reach. Copyright © 2017, American Association for the Advancement of Science.
Twisted vertex algebras, bicharacter construction and boson-fermion correspondences
International Nuclear Information System (INIS)
Anguelova, Iana I.
2013-01-01
The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras
From starproducts to Drinfeld-twists. Present and future applications
International Nuclear Information System (INIS)
Koch, Florian
2008-01-01
Physics comes up with models that invoke noncommutative structures in configuration space. Such structures are dual to the deformed coalgebra sector of a represented symmetry algebra. In the mean time such deformations are performed in terms of the symmetry algebra itself via twists or quasitriangular structures. One might thus find oneself in the bad situation that the symmetry algebra is not large enough to provide the required twist that dually matches the noncommutative structure found. It thus has to remain in the unpleasant state of being without any notion of symmetry. We show how starproducts can be pushed to twists by introducing a larger algebra that accommodates any finite dimensional representation of a Lie-algebra. This new algebra is similar to a Heisenberg-algebra but in contrast to the latter can be enhanced to a Hopf-algebra. Some Examples are given. (author)
Fast Torsional Artificial Muscles from NiTi Twisted Yarns.
Mirvakili, Seyed M; Hunter, Ian W
2017-05-17
Torsional artificial muscles made of multiwalled carbon nanotube/niobium nanowire yarns have shown remarkable torsional speed and gravimetric torque. The muscle structure consists of a twisted yarn with half of its length infiltrated with a stimuli-responsive guest material such as paraffin wax. The volumetric expansion of the guest material creates the torsional actuation in the yarn. In the present work, we show that this type of actuation is not unique to wax-infiltrated carbon multiwalled nanotube (MWCNT) or niobium nanowire yarns and that twisted yarn of NiTi alloy fibers also produces fast torsional actuation. By gold-plating half the length of a NiTi twisted yarn and Joule heating it, we achieved a fully reversible torsional actuation of up to 16°/mm with peak torsional speed of 10 500 rpm and gravimetric torque of 8 N·m/kg. These results favorably compare to those of MWCNTs and niobium nanowire yarns.
Note on the rank of quadratic twists of Mordell equations
Chang, Sungkon
2005-01-01
14H52 : Elliptic curves Let E be the elliptic curve given by a Mordell equation y^2=x^3-A where A is an integer. For certain A, we use Stoll's formula to compute a lower bound for the proportion of square-free integers D up to X such that the Mordell-Weil rank of the quadratic twist by D is less than 2k, for given non-negative k. We also compute an upper bound for a certain average rank of quadratic twists of E.
On the role of higher twists in describing scaling violation
International Nuclear Information System (INIS)
Chyla, J.; Rames, J.
1986-06-01
A method of comparing the QCD predictions for nucleon structure functions scaling violation with deep inelastic scattering data is proposed, the main feature of which being the assumption that the value of Λ QCD parameter is known independently of perturbative analyses. We conjecture that a suitable way of determination Λ is through lattice Monte Carlo calculations of quantities like hadronic masses and consider the Λ MS -bar value thus found around 100 MeV. The method is then used for quantitative analysis of twist 4 contributions, and problems related to higher twist effects determination are discussed
Borel resummation of soft gluon radiation and higher twists
International Nuclear Information System (INIS)
Forte, Stefano; Ridolfi, Giovanni; Rojo, Joan; Ubiali, Maria
2006-01-01
We show that the well-known divergence of the perturbative expansion of resummed results for processes such as deep-inelastic scattering and Drell-Yan in the soft limit can be treated by Borel resummation. The divergence in the Borel inversion can be removed by the inclusion of suitable higher twist terms. This provides us with an alternative to the standard 'minimal prescription' for the asymptotic summation of the perturbative expansion, and it gives us some handle on the role of higher twist corrections in the soft resummation region
Gerbes over posets and twisted C*-dynamical systems
Vasselli, Ezio
2017-01-01
A base $\\Delta$ generating the topology of a space $M$ becomes a partially ordered set (poset), when ordered under inclusion of open subsets. Given a precosheaf over $\\Delta$ of fixed-point spaces (typically C*-algebras) under the action of a group $G$, in general one cannot find a precosheaf of $G$-spaces having it as fixed-point precosheaf. Rather one gets a gerbe over $\\Delta$, that is, a "twisted precosheaf" whose twisting is encoded by a cocycle with coefficients in a suitable 2-group. W...
Prenatal Development: How Your Baby Grows During Pregnancy
... Management Education & Events Advocacy For Patients About ACOG Prenatal Development: How Your Baby Grows During Pregnancy Home ... Grows During Pregnancy FAQ156, June 2015 PDF Format Prenatal Development: How Your Baby Grows During Pregnancy Pregnancy ...
DEFF Research Database (Denmark)
Tran, Phuoc T; Shroff, Emelyn H; Burns, Timothy F
2012-01-01
overexpressed in primary human lung tumors. The suppression of TWIST1 in human lung cancer cells also induced cellular senescence. Hence, TWIST1 is a critical regulator of cellular senescence programs, and the suppression of TWIST1 in human tumors may be an effective example of pro-senescence therapy....... mouse model and in human lung tumors that the inhibition of Twist1 restores a senescence program inducing the loss of a neoplastic phenotype. The Twist1 gene encodes for a transcription factor that is essential during embryogenesis. Twist1 has been suggested to play an important role during tumor...... progression. However, there is no in vivo evidence that Twist1 plays a role in autochthonous tumorigenesis. Through two novel transgenic mouse models, we show that Twist1 cooperates with Kras(G12D) to markedly accelerate lung tumorigenesis by abrogating cellular senescence programs and promoting...
Baby Boom, Asset Market Meltdown and Liquidity Trap
Junning Cai
2004-01-01
A so-called “asset market meltdown hypothesis” predicts that baby boomers’ large savings will drive asset market booms that will eventually collapse because of the boomers’ large retirement dissavings. As good news to baby boomers, our analysis shows that this meltdown hypothesis is fundamentally flawed; and baby-boom-driven asset market booms may not necessarily collapse. However, bad news is that, in the case where meltdowns are about to happen, forward-looking baby boomers’ attempts to esc...
Should we maintain baby hatches in our society?
Asai, Atsushi; Ishimoto, Hiroko
2013-01-01
Abstract Background A baby hatch called the “Stork’s Cradle” has been in place at Jikei Hospital in Kumamoto City, Japan, since May 10, 2007. Babyklappes were first established in Germany in 2000, and there are currently more than 90 locations. Attitudes regarding baby hatches are divided in Japan and neither opinions for nor against baby hatches have thus far been overwhelming. To consider the appropriateness of baby hatches, we present and examine the validity of each major objection to est...
Baby Cry Detection in Domestic Environment using Deep Learning
Ijzerman, Hans
2017-01-01
Automatic detection of a baby cry in audio signals is an essential step in applications such as remote baby monitoring. It is also important for researchers, who study the relation between baby cry patterns and various health or developmental parameters. In this paper, we propose two machine-learning algorithms for automatic detection of baby cry in audio recordings. The first algorithm is a low-complexity logistic regression classifier, used as a reference. To train this classifier, we extra...
Expedient Treatment of a Collodion Baby
Directory of Open Access Journals (Sweden)
Michael Chung
2011-01-01
Full Text Available Only ~270 cases of collodion babies have been reported in the literature since 1892. As the name suggests, the term “collodion baby” refers to a phenotype that can be characterized by a yellow, shiny, tight parchment-like membrane stretched over the skin. Although the collodion membrane is only an evanescent condition of the newborn, neonatal complications can occur in 45% of all collodion babies, leading to a mortality rate of ~11% in the first few weeks of life. Most children born as collodion babies will spontaneously desquamate within 2 weeks, but may be as long as 3 months. Eventually, these children develop signs of one of several types of ichthyosis, which gives the skin the appearance of “fish scales.” We report a unique case of a Caucasian male that was born as a Collodion baby at the University of Kentucky Children's Hospital in Lexington, Kentucky. Although the impairment of the skin barrier function put the patient at risk for a number of complications, he improved significantly after being treated with emollients and antibiotics. In contrast to previous findings, we found that skin emollients were beneficial and did not increase the risk of infection.
Baby Bell Libraries?--An Update.
Kessler, Jack
1993-01-01
Discusses the emerging three-tiered structure (i.e., the "Baby Bells," network nodes, and information marketers) that will assume responsibility for implementing a new national information network and getting networked information to the public. The role of libraries related to networked information is also considered. (EA)
Completion Agenda for Baby Boomers. Commentary
Fishman, Seth
2011-01-01
In the article, "Completion Agenda for Baby Boomers", Moltz highlights how community colleges are currently implementing programs, such as the American Association of Community Colleges' Plus 50 Completion strategy, to encourage older learners to return to America's college campuses. The effects of the recent recession and the…
Babies Bottom Out--A 'Maybe Boom'
Science News, 1977
1977-01-01
Data for the period September 1976 through April 1977 indicate a rise in the United States birth rate; however, the rate is still below the replacement level. It is speculated that the increase is an "echo" effect to the post-World War II baby boom which peaked in 1957. (SL)
How to Care for Your Baby's Teeth
... in them. You can give your baby a pacifier but only when needed. Try to stop using a pacifier around age 2. The same age applies for ... who suck their thumbs. Prolonged use of a pacifier or thumb sucking can cause problems with teeth ...
Social Early Stimulation of Trisomy-21 Babies
Aparicio, Maria Teresa Sanz; Balana, Javier Menendez
2003-01-01
This study was initiated with twenty Down's syndrome babies to verify whether subjects undergoing social early stimulation would benefit from this type of treatment. An experimental study was designed with two training groups: visual or written instructions. The analyses of the results established statistically significant differences in the…
Faith, existence and birth of preterm babies
DEFF Research Database (Denmark)
Rasmussen, Christina Prinds
The aim is to explore if becoming a mother preterm of a premature baby, actualises existential and religious issues, and to explore the impact of the considerations in their way of coping. It is thus to shed light on these issues, that can both function as a positive coping-resource and the oppos...
Baby massage: a dialogue of touch.
Bond, Cherry
2002-01-01
The significance and benefits of touch and massage for preterm infants in Neonatal Intensive Care Units and in the community are discussed. The article emphasises the value of massage in helping parents to bond with their baby and as part of family-centred care. A bibliography is included.
Me? Have a Baby? Preconception Health
Centers for Disease Control (CDC) Podcasts
2012-10-01
Preconception health means taking care of your own health now so youâll be healthy for yourself and your future baby. Created: 10/1/2012 by National Center on Birth Defects and Developmental Disabilities (NCBDDD). Date Released: 10/1/2012.
Me? Have Another Baby? Preconception Health
Centers for Disease Control (CDC) Podcasts
2012-10-01
Preconception health means taking care of your own health now so youâll be healthy for yourself and your future baby. Created: 10/1/2012 by National Center on Birth Defects and Developmental Disabilities (NCBDDD). Date Released: 10/1/2012.
The baby has not come: obstructed labour
African Journals Online (AJOL)
Introduction. This article is about how to recognize obstructed labour and deal with it in a way that preserves the life and health of mother and child. It is for midwives and others who work in maternity care and is based on our experiences in Yei, South Sudan. Obstructed labour means that the baby is too big to pass through ...
Vafa-Witten theory on N = 2 and N = 4 twisted superspace in four dimensions
International Nuclear Information System (INIS)
Kato, Junji; Miyake, Akiko
2009-01-01
We construct a new off-shell twisted real form of the hypermultiplet with a scalar and an anti-self-dual tensor superfields. Using the N = 2 twisted superspace formalism, we construct a Donaldson-Witten theory coupled to the real form of the hypermultiplet. We show that this action possesses the Vafa-Witten type N = 4 twisted supersymmetry at the on-shell level. We also reconstruct the action using a N = 4 twisted superconnection formalism.
Why at Least 39 Weeks Is Best for Your Baby?
... more health problems at birth and later in life than babies born later. Being pregnant 39 weeks gives your baby's body all the time it needs to grow. Here's why your baby needs 39 weeks: Important organs, like his brain, lungs and liver, get the time they need ...
Kangaroo Mother Care Management of a 750 Ggrammes Baby: A ...
African Journals Online (AJOL)
This paper presents the successful management of 750 grammes low birth weight baby using kangaroo mother care in the hospital and at home. The baby had suffered a variety of morbidities associated with prematurity in the early neonatal period. Key words: Kangaroo mother care, low birth weight babies ...
Your Baby's Hearing, Vision, and Other Senses: 11 Months
... conversation Taste and Smell By this age, your baby is developing food preferences . Keep offering foods with a variety of ... can take 10 tries or more before a baby learns to like new food. Explore the sense of smell with your baby. ...
Your Baby's Hearing, Vision, and Other Senses: 7 Months
... a mobile over the crib or wall hangings within reach, remove them so your baby doesn't get hurt. Babies this age enjoy more complex patterns and color variations. Try reading books with large, brightly colored pictures to your baby, ...
Risk factors for neonatal jaundice in babies presenting at the ...
African Journals Online (AJOL)
... in this study was relatively high particularly in association with sepsis, prematurity and asphyxia. Mortality was higher in out-born babies than in in-born babies (p= 0.00). Conclusion: Early presentation of babies and adequate management of sepsis and prematurity will reduce mortality associated with neonatal jaundice.
Infants & Toddlers: How Babies Use Gestures to Communicate
Honig, Alice Sterling
2004-01-01
Evolution has provided babies with wonderful ways to get the loving attention and care that they need from adults. When a baby is distressed, his cry is the most primitive and powerful tool for bringing help. By the time a baby is 2 or 3 months old, his dazzling smile and crooked grin evokes tenderness, smiles, and nurturance from adults who are…
Ackerman, Paul J; van de Lagemaat, Jao; Smalyukh, Ivan I
2015-01-21
Some of the most exotic condensed matter phases, such as twist grain boundary and blue phases in liquid crystals and Abrikosov phases in superconductors, contain arrays of topological defects in their ground state. Comprised of a triangular lattice of double-twist tubes of magnetization, the so-called 'A-phase' in chiral magnets is an example of a thermodynamically stable phase with topologically nontrivial solitonic field configurations referred to as two-dimensional skyrmions, or baby-skyrmions. Here we report that three-dimensional skyrmions in the form of double-twist tori called 'hopfions', or 'torons' when accompanied by additional self-compensating defects, self-assemble into periodic arrays and linear chains that exhibit electrostriction. In confined chiral nematic liquid crystals, this self-assembly is similar to that of liquid crystal colloids and originates from long-range elastic interactions between particle-like skyrmionic torus knots of molecular alignment field, which can be tuned from isotropic repulsive to weakly or highly anisotropic attractive by low-voltage electric fields.
Beliefs about the use of baby walkers.
Chagas, Paula S C; Mancini, Marisa C; Tirado, Marcella G A; Megale, Luiz; Sampaio, Rosana F
2011-01-01
To understand the opinion of the parents about the baby walker and compare the age of gait acquisition between infants that used a walker and those that did not. In this quali-quantitative study, an interview involving a semi-structured questionnaire was carried out with 26 parents, 14 of whose infants used the equipment (BWG) and 12 of whose infants did not (NBWG) prior to gait acquisition. After extensive content analysis, categories for interpreting the results emerged. For data triangulation, the age of gait acquisition was documented by weekly telephone contact. Student's t-test was used for comparison between groups with a significance level of α=0.05. The following categories were identified in the parents' reports: a) information about the baby walker; b) doubt/decision to use it vs. certainty about not using it; c) beliefs about the use of a baby-walker; and d) benefits and harm from use. The age of independent gait acquisition did not differ between groups (p=0.837): BWG initiated gait at 376.17 (SD=32.62) days and NBWG did so at 378.75 (SD=27.99) days. The beliefs and feelings that permeate the decision to use a baby walker illustrate the different rationales adopted by parents about the role of this equipment in the child's development of gait and autonomy. The use of a baby walker did not influence the age of gait acquisition. The results broaden the understanding of choices that influence child-rearing practices prior to gait acquisition.
On the space of connections having non-trivial twisted harmonic spinors
Energy Technology Data Exchange (ETDEWEB)
Bei, Francesco, E-mail: bei@math.hu-berlin.de [Institut für Mathematik, Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin (Germany); Waterstraat, Nils, E-mail: n.waterstraat@kent.ac.uk [School of Mathematics, Statistics & Actuarial Science, University of Kent, Canterbury, Kent CT2 7NF (United Kingdom)
2015-09-15
We consider Dirac operators on odd-dimensional compact spin manifolds which are twisted by a product bundle. We show that the space of connections on the twisting bundle which yields an invertible operator has infinitely many connected components if the untwisted Dirac operator is invertible and the dimension of the twisting bundle is sufficiently large.
Mathematical simulation of a twisted pseudoplastic fluid flow in a cylindrical channel
Matvienko, O. V.; Bazuev, V. P.; Yuzhanova, N. K.
2011-05-01
The results of investigations of a pseudoplastic fluid twisted flow in a cylindrical channel are presented. With increase in the shear stresses caused by the flow twisting, the effective viscosity decreases. As a result, in the axial part of the channel a zone of lower pressure is formed which, at smaller flow twisting, leads to the formation of the zone of backward flows.
On the space of connections having non-trivial twisted harmonic spinors
International Nuclear Information System (INIS)
Bei, Francesco; Waterstraat, Nils
2015-01-01
We consider Dirac operators on odd-dimensional compact spin manifolds which are twisted by a product bundle. We show that the space of connections on the twisting bundle which yields an invertible operator has infinitely many connected components if the untwisted Dirac operator is invertible and the dimension of the twisting bundle is sufficiently large
Conservative Management of Twisted Ischemic Adnexa in Early ...
African Journals Online (AJOL)
She underwent emergency surgery with a provisional diagnosis of torsion of left adnexa. Mini‑laparotomy, detorsion of the twisted adnexa and ovarian cystectomy with reconstruction was performed thus conserving the tube and ovary. The pregnancy progressed normally; follow‑up ultrasound scans showed normal ...
The Hardy inequality and the heat equation in twisted tubes
Czech Academy of Sciences Publication Activity Database
Krejčiřík, David; Zuazua, E.
2010-01-01
Roč. 94, č. 3 (2010), s. 277-303 ISSN 0021-7824 R&D Projects: GA MŠk LC06002 Institutional research plan: CEZ:AV0Z10480505 Keywords : Twisted tubes * Hardy inequality * Dirichlet Laplacian Subject RIV: BA - General Mathematics Impact factor: 1.450, year: 2010
Twisted equivariant K-theory, groupoids and proper actions
Cantarero, Jose
2009-01-01
In this paper we define twisted equivariant K-theory for actions of Lie groupoids. For a Bredon-compatible Lie groupoid, this defines a periodic cohomology theory on the category of finite CW-complexes with equivariant stable projective bundles. A classification of these bundles is shown. We also obtain a completion theorem and apply these results to proper actions of groups.
Twisted topological solitons and dislocations in a polymer crystal
DEFF Research Database (Denmark)
Savin, A. V.; Khalack, J. M.; Christiansen, Peter Leth
2002-01-01
of adjacent molecular chains in the polymer crystal). It is shown that some of these defects called "twisted topological solitons" can propagate with a stationary profile and velocity. To describe the dynamics of these solitons, a model that accounts for the three components of the molecular displacements...
A Hardy inequality in a twisted Dirichlet-Neumann waveguide
Czech Academy of Sciences Publication Activity Database
Kovařík, Hynek; Krejčiřík, David
2008-01-01
Roč. 281, č. 8 (2008), s. 1159-1168 ISSN 0025-584X R&D Projects: GA MŠk LC06002 Institutional research plan: CEZ:AV0Z10480505 Keywords : Laplacian * Dirichlet and Neumann boundary conditions * twist Subject RIV: BE - Theoretical Physics Impact factor: 0.537, year: 2008
Spectral estimates for Dirichlet Laplacians on perturbed twisted tubes
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Barseghyan, Diana
2014-01-01
Roč. 8, č. 1 (2014), s. 167-183 ISSN 1846-3886 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Drichlet Laplacian * twisted tube * discrete spectrum * eigenvalue estimates Subject RIV: BE - Theoretical Physics Impact factor: 0.583, year: 2014
Twisted mass lattice QCD with non-degenerate quark masses
International Nuclear Information System (INIS)
Muenster, Gernot; Sudmann, Tobias
2006-01-01
Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term is considered in the framework of chiral perturbation theory. For two and three numbers of quark flavours, respectively, with non-degenerate quark masses the pseudoscalar meson masses and decay constants are calculated in next-to-leading order including lattice effects quadratic in the lattice spacing a
Would You Rather (WYR), with a Sexual Health Twist!
Rosen, Brittany; McNeill, Elisa Beth; Wilson, Kelly
2014-01-01
Would You Rather (WYR), with a Sexual Health Twist! teaching technique uses two youth games, "Would you rather…" and Twister®, to actively engage students in developing decision-making skills regarding human sexuality. Utilizing the "Would you rather" choices, the teacher provides a short scenario with two difficult choices.…
Coherent nonlinear electromagnetic response in twisted bilayer and ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 83; Issue 4. Coherent nonlinear electromagnetic response in twisted bilayer and few-layer graphene ... These oscillations in the population and polarization at the Dirac point in -layer graphene are seen in the nth harmonic termin the external driving frequency.
Fermionic construction of vertex operators for twisted affine algebras
International Nuclear Information System (INIS)
Frappat, L.; Sorba, P.; Sciarrino, A.
1988-03-01
We construct vertex operator representations of the twisted affine algebras in terms of fermionic (or parafermionic in some cases) elementary fields. The folding method applied to the extended Dynkin diagrams of the affine algebras allows us to determine explicitly these fermionic fields as vertex operators
Twist of Magnetic Fields in Solar Active Regions Hongqi Zhang ...
Indian Academy of Sciences (India)
tribpo
twisted field (current helicity) in the photosphere (Seehafer 1990; Pevtsov et al. 1995;. Bao & Zhang 1998). Bao & Zhang (1998) and Zhang & Bao (1999) computed the photospheric current helicity parameter h|| for 422 active regions, including most of the large ones observed in the period of 1988 1997 at Huairou Solar ...
Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening ...
Indian Academy of Sciences (India)
tribpo
netic field, which subsequently appear as active regions in the photosphere (Rust &. Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Raman et al. 1998 and the references therein).
Stability of coupled tearing and twisting modes in tokamaks
International Nuclear Information System (INIS)
Fitzpatrick, R.
1994-03-01
A dispersion relation is derived for resistive modes of arbitrary parity in a tokamak plasma. At low mode amplitude, tearing and twisting modes which have nonideal MHD behavior at only one rational surface at a time in the plasma are decoupled via sheared rotation and diamagnetic flows. At higher amplitude, more unstable open-quote compound close-quote modes develop which have nonideal behavior simultaneously at many surfaces. Such modes possess tearing parity layers at some of the nonideal surfaces, and twisting parity layers at others, but mixed parity layers are generally disallowed. At low mode number, open-quote compound close-quote modes are likely to have tearing parity layers at all of the nonideal surfaces in a very low-β plasma, but twisting parity layers become more probable as the plasma β is increased. At high mode number, unstable twisting modes which exceed a critical amplitude drive conventional magnetic island chains on alternate rational surfaces, to form an interlocking structure in which the O-points and X-points of neighboring chains line up
Intermittent energy bursts and recurrent topological change of a twisting magnetic flux tube
International Nuclear Information System (INIS)
Amo, Hiroyoshi; Sato, Tetsuya; Kageyama, Akira.
1994-09-01
When continuously twisted, a magnetic flux tube suffers a large kink distortion in the middle part of the tube, like a knot-of-tension instability of a bundle of twisted rubber strings, and reconnection is triggered starting with the twisted field lines and quickly proceeding to the untwisted field lines at the twist-untwist boundary, whereby a giant burst-like energy release takes place. Subsequently, bursts occur intermittently and reconnection advances deeper into the untwisted region. Then, a companion pair of the linked twist-untwist flux tubes reconnect with each other to return to the original axisymmetric tube. The process is thus repeatable. (author)
Passive smoking in babies: The BIBE study (Brief Intervention in babies. Effectiveness
Directory of Open Access Journals (Sweden)
Cabezas Carmen
2010-12-01
Full Text Available Abstract Background There is evidence that exposure to passive smoking in general, and in babies in particular, is an important cause of morbimortality. Passive smoking is related to an increased risk of pediatric diseases such as sudden death syndrome, acute respiratory diseases, worsening of asthma, acute-chronic middle ear disease and slowing of lung growth. The objective of this article is to describe the BIBE study protocol. The BIBE study aims to determine the effectiveness of a brief intervention within the context of Primary Care, directed to mothers and fathers that smoke, in order to reduce the exposure of babies to passive smoking (ETS. Methods/Design Cluster randomized field trial (control and intervention group, multicentric and open. Subject: Fathers and/or mothers who are smokers and their babies (under 18 months that attend pediatric services in Primary Care in Catalonia. The measurements will be taken at three points in time, in each of the fathers and/or mothers who respond to a questionnaire regarding their baby's clinical background and characteristics of the baby's exposure, together with variables related to the parents' tobacco consumption. A hair sample of the baby will be taken at the beginning of the study and at six months after the initial visit (biological determination of nicotine. The intervention group will apply a brief intervention in passive smoking after specific training and the control group will apply the habitual care. Discussion Exposure to ETS is an avoidable factor related to infant morbimortality. Interventions to reduce exposure to ETS in babies are potentially beneficial for their health. The BIBE study evaluates an intervention to reduce exposure to ETS that takes advantage of pediatric visits. Interventions in the form of advice, conducted by pediatric professionals, are an excellent opportunity for prevention and protection of infants against the harmful effects of ETS. Trial Registration Clinical
Unique CCT repeats mediate transcription of the TWIST1 gene in mesenchymal cell lines
International Nuclear Information System (INIS)
Ohkuma, Mizue; Funato, Noriko; Higashihori, Norihisa; Murakami, Masanori; Ohyama, Kimie; Nakamura, Masataka
2007-01-01
TWIST1, a basic helix-loop-helix transcription factor, plays critical roles in embryo development, cancer metastasis and mesenchymal progenitor differentiation. Little is known about transcriptional regulation of TWIST1 expression. Here we identified DNA sequences responsible for TWIST1 expression in mesenchymal lineage cell lines. Reporter assays with TWIST1 promoter mutants defined the -102 to -74 sequences that are essential for TWIST1 expression in human and mouse mesenchymal cell lines. Tandem repeats of CCT, but not putative CREB and NF-κB sites in the sequences substantially supported activity of the TWIST1 promoter. Electrophoretic mobility shift assay demonstrated that the DNA sequences with the CCT repeats formed complexes with nuclear factors, containing, at least, Sp1 and Sp3. These results suggest critical implication of the CCT repeats in association with Sp1 and Sp3 factors in sustaining expression of the TWIST1 gene in mesenchymal cells
Beliefs about the use of baby walkers
Chagas,Paula S. C.; Mancini,Marisa C.; Tirado,Marcella G. A.; Megale,Luiz; Sampaio,Rosana F.
2011-01-01
OBJECTIVES: To understand the opinion of the parents about the baby walker and compare the age of gait acquisition between infants that used a walker and those that did not. METHODS: In this quali-quantitative study, an interview involving a semi-structured questionnaire was carried out with 26 parents, 14 of whose infants used the equipment (BWG) and 12 of whose infants did not (NBWG) prior to gait acquisition. After extensive content analysis, categories for interpreting the results emerged...
Shaken baby syndrome: a nursing perspective.
Chiocca, E M
1995-01-01
Child abuse by whiplash-shaking can lead to severe injury in infants, including cerebral damage, neurological defects, blindness, and mental retardation. These findings are seen often without external evidence of head injury. Nurses should suspect shaken baby syndrome (SBS) in infants less than 1 year of age who present with apnea, seizures, lethargy or drowsiness, bradycardia, respiratory difficulty, coma, or death. Subdural and retinal hemorrhages accompanied by the absence of external signs of trauma are hallmarks of the syndrome.
Constipation in babies: Nutritional and behavioral aspects
Directory of Open Access Journals (Sweden)
A. A. Tyazheva
2015-01-01
Full Text Available Constipation in children remains one of the topical problems of pediatrics and pediatric gastroenterology. Functional constipation accounts for about 95% of its cases. The article deals with the main causes of constipation in babies. An algorithm for the management of an infant with functional constipation involves correction of infant feeding in addition to medical treatment. Dietary fiber deficiency in infants may cause constipation. That is why functional foods should be used for infant feeding.
MODEL SEIR UNTUK EPIDEMI FLU BABI PADA POPULASI BABI DENGAN LAJU KONTAK JENUH
Directory of Open Access Journals (Sweden)
M Kharis
2012-09-01
Full Text Available Babi merupakan inang alami dari virus influensa yang secara anatomis, fisiologis, dan imunitas mirip (similar dengan yang ada pada manusia. Virus influenza subtipe A yang ada pada manusia yaitu H1N1, H3N2 dan H1N2 merupakan enzootic pada populasi babi di dunia. babi dapat terinfeksi oleh turunan-turunan virus influenza tipe A dari manusia maupun dari burung dan dalam hal ini dianggap sebagai inang sementara (Intermediate hosts dari turunan-turunan virus flu babi yang berpotensi menyebabkan epidemi bahkan pandemi. Evolusi antigenik dari virus influenza pada babi terjadi dengan laju sekitar 6 kali lebih lambat dibandingkan dengan virus influenza pada manusia. Dalam tulisan ini akan dikaji model matematika untuk epidemi flu babi pada populasi babi. Model yang diberikan merupakan model deterministik dengan laju kontak jenuh yang merupakan perumuman dari laju kontak standar. Perumuman ini dinyatakan dengan adanya probabilitas suatu individu melakukan kontak yang dinyatakan sebagai suatu fungsi dari populasi. Pengkajian yang dilakukan meliputi penentuan titik ekuilibrium model matematika dan analisa kestabilannya. Diharapkan hasil kajian ini dapat bermanfaat dalam penanggulangan wabah flu babi pada sumber utama yaitu populasi babi sehingga dapat dilakukan pencegahan sebelum mewabah di populasi manusia.Â Pigs are a natural host of influenza virus that are similar anatomically, physiologically, and immunity which in humans. Influenza viruses of A subtype in humans are H1N1, H3N2 and H1N2. They are enzootic in the swine population in the world. Pigs can be infected by strains of type A influenza viruses from humans or from birds. Pigs are considered as a temporary host (intermediate hosts of the derivatives of the swine flu virus that has the potential to cause epidemics and even pandemics. Antigenic evolution of influenza viruses in pigs occurred at rate about 6 times slower than the influenza viruses in humans. In this paper the mathematical model
Directory of Open Access Journals (Sweden)
K. Budaarsa
2015-06-01
Full Text Available Penelitian ini bertujuan untuk mengetahui jenis-jenis hijauan yang diberikan sebagai pakan ternak babi dan cara penggunaannya di propvinsi Bali. Penelitian dilakukan dengan metode survei di seluruh kabupaten dan kota di Bali. Pengambilan sampel dilakukan dengan teknik stratified random sampling, dengan pengelompokan atas dataran rendah dan dataran tinggi di masing-masing kabupaten dan kota. Pada masing-masing kelompok di ambil 2 orang peternak babi tradisional, sehingga ada 4 peternak yang diwawancarai di masing-masing kabupaten dan kota atau 32 peternak di seluruh Bali. Hasil survei menunjukkan bahwa ada perbedaan hijauan yang diberikan oleh peternak di dataran rendah dan dataran tinggi. Jenis hijauan yang diberikan di dataran rendah antara lain: batang pisang (Musa paradisiaceae, kangkung (Ipomaea aquatica, biah-biah (Limnocharis flava, dan eceng gondok (Eichornia crassipes. Sedamgkan di dataran tinggi antara lain: batang pisang (Musa paradisiaceae, ketela rambat (Ipomaea batatas, daunt alas (Colocasia esculenta daun lamtoro (Leucaena leucocephala dan dag-dagse (Pisonia alba. Batang pisang dominan (95 % diberikan di dataran rendah maupun di dataran tinggi. Pemberian hijauan ada dengan cara direbus ada yang diberikan dalam bentuk segar. Kesimpulan dari penelitian ini adalah terdapat keragaman jenis hijauan pakan babi dan cara pemberiannya antara di dataran rendah dengan dataran tinggi di Bali. Batang pisang merupakan hijauan yang paling banyak digunakan untuk pakan babi pada peternakan babi tradisional, baik pada dataran rendah maupun dataran tinggi.
Mortality in meconium aspiration syndrome in hospitalized babies.
Anwar, Zahid; Butt, Tayyaba Khawar; Kazi, Muhammad Yaqub
2011-11-01
To determine the outcome of the babies in terms of mortality with the diagnosis of Meconium Aspiration Syndrome (MAS). An observational study. The Neonatal Unit of Services Institute of Medical Sciences and Services Hospital, Lahore, Pakistan, from February 2008 to January 2009. All the babies admitted to the neonatal unit during the period of study with the diagnosis of MAS were included. At admission, demographic, maternal, antenatal and natal data were recorded on a specific form. The progress of the baby, including need for ventilation, medications, complications and outcome were also followed and documented. One hundred and nine babies admitted with MAS, 32% died. Most of the babies (n=73) were admitted from our obstetrical unit and the rest through the emergency department. Majority (60 of 109) were admitted within the 1st hour of life. Most (14 of 15) of the newborns requiring intubation within 1st hour of life, died. Forty four babies were ventilated and 35 of these babies succumbed. Of ventilated babies, 11 developed pneumothoraces. Seventy two percent (13 out of 18) of expired babies stayed for less than 24 hours. Mortality rate for MAS was higher in the study group as compared to international figures. It was especially high in babies requiring mechanical ventilation in 1st hour of life or with co-existing severe hypoxic ischemic encephalopathy.
Ahmed, Adam S.; Esser, Bryan D.; Rowland, James; McComb, David W.; Kawakami, Roland K.
2017-06-01
Skyrmions are localized magnetic spin textures whose stability has been shown theoretically to depend on material parameters including bulk Dresselhaus spin orbit coupling (SOC), interfacial Rashba SOC, and magnetic anisotropy. Here, we establish the growth of a new class of artificial skyrmion materials, namely B20 superlattices, where these parameters could be systematically tuned. Specifically, we report the successful growth of B20 superlattices comprised of single crystal thin films of FeGe, MnGe, and CrGe on Si(1 1 1) substrates. Thin films and superlattices are grown by molecular beam epitaxy and are characterized through a combination of reflection high energy electron diffraction, X-ray diffraction, and cross-sectional scanning transmission electron microscopy (STEM). X-ray energy dispersive spectroscopy (XEDS) distinguishes layers by elemental mapping and indicates good interface quality with relatively low levels of intermixing in the [CrGe/MnGe/FeGe] superlattice. This demonstration of epitaxial, single-crystalline B20 superlattices is a significant advance toward tunable skyrmion systems for fundamental scientific studies and applications in magnetic storage and logic.
Sudden polarization effect in methyl-substituted twisted polyenes
International Nuclear Information System (INIS)
Baraldi, I.; Bruni, M.C.; Momicchioli, F.; Ponterini, G.
1981-01-01
Sudden polarization effect was investigated for a special type of nonsymmetric biradical systems, i.e. terminally twisted polyenes methyl substituted at the rotated CH 2 group. Systems with 2 to 4 conjugated double bonds were studied. Dipole moments of S 0 , S 1 and S 2 states were calculated within the framework of the INDO approximations, by using a dual basis of SCF MOs (open shell and closed shell) and performing differently sized CIs (selected with reference to the basic 3 x 3 CI biradical description). The resulting excited-state polarization characteristics (size and suddenness) are discussed with reference to the previously studied unsubstituted polyenes. In this respect the most important point is that CH 3 substitution at the terminal twisted methylene markedly enhances the polarization size (approximately 2D). This indicates that small perturbations occurring at one radical site may cause unexpectedly large changes in charge distributions of excited biradicals. (author)
The dipole representation of vector meson electroproduction beyond leading twist
International Nuclear Information System (INIS)
Besse, A.; Szymanowski, L.; Wallon, S.
2013-01-01
We link the recent computation beyond leading twist of the impact factor of the transition γ T ⁎ →ρ T performed in the light-cone collinear approach, to the dipole picture by expressing the hard part of the process through its Fourier transform in coordinate space. We show that in the Wandzura–Wilczek approximation the impact factor up to twist 3 factorises in the wave function of the photon combined with the distribution amplitudes of the ρ-meson and the colour dipole scattering amplitude with the t-channel gluons. We show also that beyond the Wandzura–Wilczek approximation, the hard contribution of the amplitude still exhibits the signature of the interaction of a single colour dipole with the t-channel gluons. This result allows a phenomenological approach of the helicity amplitudes of the leptoproduction of vector meson, by combining our results to a dipole/target scattering amplitude model.
BK-parameter from Nf=2 twisted mass lattice QCD
International Nuclear Information System (INIS)
Constantinou, M.; Dimopoulos, P.; Frezzotti, R.; INFN, Rome
2011-01-01
We present an unquenched N f = 2 lattice computation of the B K parameter which controls K 0 - anti K 0 oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the B K parameter which is both multiplicatively renormalizable and O(a) improved. Employing the non-perturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get B RGI K =0.729±0.030, a number well in line with the existing quenched and unquenched determinations. (orig.)