WorldWideScience

Sample records for suspected orbital periods

  1. Discrete symmetries in periodic-orbit theory

    International Nuclear Information System (INIS)

    Robbins, J.M.

    1989-01-01

    The application of periodic-orbit theory to systems which possess a discrete symmetry is considered. A semiclassical expression for the symmetry-projected Green's function is obtained; it involves a sum over classical periodic orbits on a symmetry-reduced phase space, weighted by characters of the symmetry group. These periodic orbits correspond to trajectories on the full phase space which are not necessarily periodic, but whose end points are related by symmetry. If the symmetry-projected Green's functions are summed, the contributions of the unperiodic orbits cancel, and one recovers the usual periodic-orbit sum for the full Green's function. Several examples are considered, including the stadium billiard, a particle in a periodic potential, the Sinai billiard, the quartic oscillator, and the rotational spectrum of SF 6

  2. Periodic orbits near the particle resonance in galaxies

    CERN Document Server

    Contopoulos, George

    1978-01-01

    Near the particle resonance of a spiral galaxy the almost circular periodic orbits that exist inside the resonance (direct) or outside it (retrograde) are replaced by elongated trapped orbits around the maxima of the potential L/sub 4/ and L/sub 5/. These are the long- period trapped periodic orbits. The long-period orbits shrink to the points L/sub 4/, L/sub 5/ for a critical value of the Hamiltonian h. For still larger h, a family of short-period trapped orbits appears, with continuously growing size. The evolution of the periodic orbits with h is followed, theoretically and numerically, from the untrapped orbits to the long-periodic orbits and then to the short-periodic orbits, mainly in the case of a bar. In a tight spiral case an explanation of the asymmetric periodic and banana orbits is given, and an example of short-period orbits not surrounding L/sub 4/ or L/sub 5/ is provided. Another family of periodic orbits reaching corotation is trapped at the inner Lindblad resonance. (5 refs).

  3. Orbital periods of recurrent novae

    International Nuclear Information System (INIS)

    Schaefer, B.E.

    1990-01-01

    The class of recurrent novae (RN) with thermonuclear runaways contains only three systems (T Pyx, U Sco, and V394 CrA), for which no orbital periods are known. This paper presents a series of photometric observations where the orbital periods for all three systems are discovered. T Pyx is found to have sinusoidal modulation with an amplitude of 0.08 mag and a period of 2.3783 h (with a possible alias of 2.6403 h). U Sco is found to be an eclipsing system with an eclipse amplitude of roughly 1.5 mag and an orbital period of 1.2344 days. V394 CrA is found to have sinusoidal modulation with an amplitude of 0.5 mag and a period of 0.7577 days. Thus two out of three RN with thermonuclear runaways (or five out of six for all RN) have evolved companions. 16 refs

  4. Topological imprint for periodic orbits

    International Nuclear Information System (INIS)

    Martín, Jesús San; Moscoso, Ma José; Gómez, A González

    2012-01-01

    The more self-crossing points an orbit has the more complex it is. We introduce the topological imprint to characterize crossing points and focus on the period-doubling cascade. The period-doubling cascade topological imprint determines the topological imprint for orbits in chaotic bands. In addition, there is a closer link between this concept and the braids studied by Lettelier et al (2000 J. Phys. A: Math. Gen. 33 1809–25). (paper)

  5. On periodic orbits in discrete-time cascade systems

    Directory of Open Access Journals (Sweden)

    Huimin Li

    2006-01-01

    Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.

  6. Periodic orbits around areostationary points in the Martian gravity field

    International Nuclear Information System (INIS)

    Liu Xiaodong; Baoyin Hexi; Ma Xingrui

    2012-01-01

    This study investigates the problem of areostationary orbits around Mars in three-dimensional space. Areostationary orbits are expected to be used to establish a future telecommunication network for the exploration of Mars. However, no artificial satellites have been placed in these orbits thus far. The characteristics of the Martian gravity field are presented, and areostationary points and their linear stability are calculated. By taking linearized solutions in the planar case as the initial guesses and utilizing the Levenberg-Marquardt method, families of periodic orbits around areostationary points are shown to exist. Short-period orbits and long-period orbits are found around linearly stable areostationary points, but only short-period orbits are found around unstable areostationary points. Vertical periodic orbits around both linearly stable and unstable areostationary points are also examined. Satellites in these periodic orbits could depart from areostationary points by a few degrees in longitude, which would facilitate observation of the Martian topography. Based on the eigenvalues of the monodromy matrix, the evolution of the stability index of periodic orbits is determined. Finally, heteroclinic orbits connecting the two unstable areostationary points are found, providing the possibility for orbital transfer with minimal energy consumption.

  7. Using periodic orbits to compute chaotic transport rates between resonance zones

    Science.gov (United States)

    Sattari, Sulimon; Mitchell, Kevin A.

    2017-11-01

    Transport properties of chaotic systems are computable from data extracted from periodic orbits. Given a sufficient number of periodic orbits, the escape rate can be computed using the spectral determinant, a function that incorporates the eigenvalues and periods of periodic orbits. The escape rate computed from periodic orbits converges to the true value as more and more periodic orbits are included. Escape from a given region of phase space can be computed by considering only periodic orbits that lie within the region. An accurate symbolic dynamics along with a corresponding partitioning of phase space is useful for systematically obtaining all periodic orbits up to a given period, to ensure that no important periodic orbits are missing in the computation. Homotopic lobe dynamics (HLD) is an automated technique for computing accurate partitions and symbolic dynamics for maps using the topological forcing of intersections of stable and unstable manifolds of a few periodic anchor orbits. In this study, we apply the HLD technique to compute symbolic dynamics and periodic orbits, which are then used to find escape rates from different regions of phase space for the Hénon map. We focus on computing escape rates in parameter ranges spanning hyperbolic plateaus, which are parameter intervals where the dynamics is hyperbolic and the symbolic dynamics does not change. After the periodic orbits are computed for a single parameter value within a hyperbolic plateau, periodic orbit continuation is used to compute periodic orbits over an interval that spans the hyperbolic plateau. The escape rates computed from a few thousand periodic orbits agree with escape rates computed from Monte Carlo simulations requiring hundreds of billions of orbits.

  8. Orbital Period Changes in WZ Sagittae

    Science.gov (United States)

    Patterson, Joseph; Stone, Geoffrey; Kemp, Jonathan; Skillman, David R.; de Miguel, Enrique; Potter, Michael; Starkey, Donn; Uthas, Helena; Jones, Jim; Slauson, Douglas; Koff, Robert; Myers, Gordon; Menzies, Kenneth; Campbell, Tut; Roberts, George; Foote, Jerry; Vanmunster, Tonny; Cook, Lewis M.; Krajci, Thomas; Ogmen, Yenal; Sabo, Richard; Seargeant, Jim

    2018-06-01

    We report a long-term (1961–2017) study of the eclipse times in the dwarf nova WZ Sagittae, in an effort to learn its rate of orbital-period change. Some wiggles with a timescale of 20–50 years are apparent, and a connection with the ∼23 year interval between dwarf-nova eruptions is possible. These back-and-forth wiggles dominate the O–C diagram, and prevent a secure measurement of the steady rate of orbital-period change.

  9. Periodic orbits and non-integrability of Henon-Heiles systems

    International Nuclear Information System (INIS)

    Llibre, Jaume; Jimenez-Lara, Lidia

    2011-01-01

    We apply the averaging theory of second order to study the periodic orbits for a generalized Henon-Heiles system with two parameters, which contains the classical Henon-Heiles system. Two main results are shown. The first result provides sufficient conditions on the two parameters of these generalized systems, which guarantee that at any positive energy level, the Hamiltonian system has periodic orbits. These periodic orbits form in the whole phase space a continuous family of periodic orbits parameterized by the energy. The second result shows that for the non-integrable Henon-Heiles systems in the sense of Liouville-Arnol'd, which have the periodic orbits analytically found with averaging theory, cannot exist any second first integral of class C 1 . In particular, for any second first integral of class C 1 , we prove that the classical Henon-Heiles system and many generalizations of it are not integrable in the sense of Liouville-Arnol'd. Moreover, the tools we use for studying the periodic orbits and the non-Liouville-Arnol'd integrability can be applied to Hamiltonian systems with an arbitrary number of degrees of freedom.

  10. Origin of very-short orbital-period binary systems

    International Nuclear Information System (INIS)

    Miyaji, S.

    1983-01-01

    Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

  11. Periodic orbits of the hydrogen molecular ion and their quantization

    International Nuclear Information System (INIS)

    Duan, Y.; Yuan, J.; Bao, C.

    1995-01-01

    In a classical study of the hydrogen molecular ion beyond the Born-Oppenheimer approximation (BOA), we have found that segments of trajectories resemble that of the Born-Oppenheimer approximation periodic orbits. The importance of this fact to the classical understanding of chemical bonding leads us to a systematic study of the periodic orbits of the planar hydrogen molecular ion within the BOA. Besides introducing a classification scheme for periodic orbits, we discuss the convergence properties of families of periodic orbits and their bifurcation patterns according to their types. Semiclassical calculations of the density of states based on these periodic orbits yield results in agreement with the exact quantum eigenvalues of the hydrogen molecular ion system

  12. Periodic orbits and recurrences: An introduction and review

    International Nuclear Information System (INIS)

    Delos, J.B.

    1993-01-01

    A pedagogical introduction to and review of essential ideas in modern classical mechanics will be presented, and relationships between classical trajectories and quantum wave functions will be discussed. Much current work is focused on the effects of classical periodic orbits on quantum density of states, absorption spectra, and wave functions. The theory was first developed by Gutzwiller, who showed that each classical periodic orbit produces a sinusoidal fluctuation in the density of states as a function of energy. Short orbits produce large-scale fluctuations, while longer orbits produce small-scale fluctuations. Actually these fluctuations reside in the Green's function of the system, so they manifest themselves in all quantum properties. Two new questions will be addressed. (1) How do we understand periodic orbits from a classical perspective? How are they created and how do they proliferate as order changes to chaos? (2) Is the theory practically limited to calculation of large-scale structures in spectra, or can it be extended to calculate individual eigenfunctions?

  13. Linear and nonlinear stability of periodic orbits in annular billiards

    Science.gov (United States)

    Dettmann, Carl P.; Fain, Vitaly

    2017-04-01

    An annular billiard is a dynamical system in which a particle moves freely in a disk except for elastic collisions with the boundary and also a circular scatterer in the interior of the disk. We investigate the stability properties of some periodic orbits in annular billiards in which the scatterer is touching or close to the boundary. We analytically show that there exist linearly stable periodic orbits of an arbitrary period for scatterers with decreasing radii that are located near the boundary of the disk. As the position of the scatterer moves away from a symmetry line of a periodic orbit, the stability of periodic orbits changes from elliptic to hyperbolic, corresponding to a saddle-center bifurcation. When the scatterer is tangent to the boundary, the periodic orbit is parabolic. We prove that slightly changing the reflection angle of the orbit in the tangential situation leads to the existence of Kolmogorov-Arnold-Moser islands. Thus, we show that there exists a decreasing to zero sequence of open intervals of scatterer radii, along which the billiard table is not ergodic.

  14. PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yu [State Key Laboratory of Astronautic Dynamics, Xi’an Satellite Control Center, Xi’an 710043 (China); Baoyin, Hexi, E-mail: jiangyu_xian_china@163.com [School of Aerospace Engineering, Tsinghua University, Beijing 100084 (China)

    2016-11-01

    The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

  15. PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

    International Nuclear Information System (INIS)

    Jiang, Yu; Baoyin, Hexi

    2016-01-01

    The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

  16. Antenatal sonographic appearance of a large orbital encephalocele: a case report and differential diagnosis of orbital cystic mass.

    Science.gov (United States)

    Ahmed, Ahmed; Noureldin, Rehab; Gendy, Mohamed; Sakr, Sharif; Abdel Naby, Mahmoud

    2013-06-01

    Orbital meningoceles and encephaloceles are rare extracranial extensions of the brain and meninges with or without direct communication between the central nervous system and the abnormal mass. We reported a rare case of large fetal orbital encephalocele; the diagnosis was suspected initially by prenatal ultrasound and confirmed by postnatal MRI and CT scans. The differential diagnosis of an intrauterine fetal cystic orbital mass includes orbital teratoma, epidermoid inclusion cysts, hemangioma or lymphangioma, congenital cystic eye, dacryocystocele, and orbital cephalocele. Copyright © 2012 Wiley Periodicals, Inc.

  17. Closed almost-periodic orbits in semiclassical quantization of generic polygons

    Science.gov (United States)

    Biswas

    2000-05-01

    Periodic orbits are the central ingredients of modern semiclassical theories and corrections to these are generally nonclassical in origin. We show here that, for the class of generic polygonal billiards, the corrections are predominantly classical in origin owing to the contributions from closed almost-periodic (CAP) orbit families. Furthermore, CAP orbit families outnumber periodic families but have comparable weights. They are hence indispensable for semiclassical quantization.

  18. Genesis and bifurcations of unstable periodic orbits in a jet flow

    International Nuclear Information System (INIS)

    Uleysky, M Yu; Budyansky, M V; Prants, S V

    2008-01-01

    We study the origin and bifurcations of typical classes of unstable periodic orbits in a jet flow that was introduced before as a kinematic model of chaotic advection, transport and mixing of passive scalars in meandering oceanic and atmospheric currents. A method to detect and locate the unstable periodic orbits and classify them by the origin and bifurcations is developed. We consider in detail period-1 and period-4 orbits playing an important role in chaotic advection. We introduce five classes of period-4 orbits: western and eastern ballistic ones, whose origin is associated with ballistic resonances of the fourth-order, rotational ones, associated with rotational resonances of the second and fourth orders and rotational-ballistic ones associated with a rotational-ballistic resonance. It is a new kind of unstable periodic orbits that may appear in a chaotic flow with jets and/or circulation cells. Varying the perturbation amplitude, we track out the origin and bifurcations of the orbits for each class

  19. Effects of Colored Noise on Periodic Orbits in a One-Dimensional Map

    Science.gov (United States)

    Li, Feng-Guo; Ai, Bao-Quan

    2011-06-01

    Noise can induce inverse period-doubling transition and chaos. The effects of the colored noise on periodic orbits, of the different periodic sequences in the logistic map, are investigated. It is found that the dynamical behaviors of the orbits, induced by an exponentially correlated colored noise, are different in the mergence of transition, and the effects of the noise intensity on their dynamical behaviors are different from the effects of the correlation time of noise. Remarkably, the noise can induce new periodic orbits, namely, two new orbits emerge in the period-four sequence at the bifurcation parameter value μ = 3.5, four new orbits in the period-eight sequence at μ = 3.55, and three new orbits in the period-six sequence at μ = 3.846, respectively. Moreover, the dynamical behaviors of the new orbits clearly show the resonancelike response to the colored noise.

  20. Effects of Colored Noise on Periodic Orbits in a One-Dimensional Map

    International Nuclear Information System (INIS)

    Li Fengguo; Ai Baoquan

    2011-01-01

    Noise can induce inverse period-doubling transition and chaos. The effects of the colored noise on periodic orbits, of the different periodic sequences in the logistic map, are investigated. It is found that the dynamical behaviors of the orbits, induced by an exponentially correlated colored noise, are different in the mergence of transition, and the effects of the noise intensity on their dynamical behaviors are different from the effects of the correlation time of noise. Remarkably, the noise can induce new periodic orbits, namely, two new orbits emerge in the period-four sequence at the bifurcation parameter value μ = 3.5, four new orbits in the period-eight sequence at μ = 3.55, and three new orbits in the period-six sequence at μ = 3.846, respectively. Moreover, the dynamical behaviors of the new orbits clearly show the resonancelike response to the colored noise. (general)

  1. Stability regions for synchronized τ-periodic orbits of coupled maps with coupling delay τ

    Energy Technology Data Exchange (ETDEWEB)

    Karabacak, Özkan, E-mail: ozkan2917@gmail.com [Department of Electronics and Communication Engineering, Istanbul Technical University, 34469 Istanbul (Turkey); Department of Electronic Systems, Aalborg University, 9220 Aalborg East (Denmark); Alikoç, Baran, E-mail: alikoc@itu.edu.tr [Department of Control and Automation Engineering, Istanbul Technical University, 34469 Istanbul (Turkey); Atay, Fatihcan M., E-mail: atay@member.ams.org [Department of Mathematics, Bilkent University, 06800 Ankara (Turkey)

    2016-09-15

    Motivated by the chaos suppression methods based on stabilizing an unstable periodic orbit, we study the stability of synchronized periodic orbits of coupled map systems when the period of the orbit is the same as the delay in the information transmission between coupled units. We show that the stability region of a synchronized periodic orbit is determined by the Floquet multiplier of the periodic orbit for the uncoupled map, the coupling constant, the smallest and the largest Laplacian eigenvalue of the adjacency matrix. We prove that the stabilization of an unstable τ-periodic orbit via coupling with delay τ is possible only when the Floquet multiplier of the orbit is negative and the connection structure is not bipartite. For a given coupling structure, it is possible to find the values of the coupling strength that stabilizes unstable periodic orbits. The most suitable connection topology for stabilization is found to be the all-to-all coupling. On the other hand, a negative coupling constant may lead to destabilization of τ-periodic orbits that are stable for the uncoupled map. We provide examples of coupled logistic maps demonstrating the stabilization and destabilization of synchronized τ-periodic orbits as well as chaos suppression via stabilization of a synchronized τ-periodic orbit.

  2. Genealogy and stability of periodic orbit families around uniformly rotating asteroids

    Science.gov (United States)

    Hou, Xiyun; Xin, Xiaosheng; Feng, Jinglang

    2018-03-01

    Resonance orbits around a uniformly rotating asteroid are studied from the approach of periodic orbits in this work. Three periodic families (denoted as I, II, and III in the paper) are fundamental in organizing the resonance families. For the planar case: (1) Genealogy and stability of Families I, II and the prograde resonance families are studied. For extremely irregular asteroids, family genealogy close to the asteroid is greatly distorted from that of the two body-problem (2BP), indicating that it is inappropriate to treat the orbital motions as perturbed Keplerian orbits. (2) Genealogy and stability of Family III are also studied. Stability of this family may be destroyed by the secular resonance between the orbital ascending node's precession and the asteroid's rotation. For the spatial case: (1) Genealogy of the near circular three-dimensional periodic families are studied. The genealogy may be broken apart by families of eccentric frozen orbits whose argument of perigee is ;frozen; in space. (2) The joint effects between the secular resonance and the orbital resonances may cause instability to three-dimensional orbital motion with orbit inclinations close to the critical values. Applying the general methodology to a case study - the asteroid Eros and also considering higher order non-spherical terms, some extraordinary orbits are found, such as the ones with orbital plane co-rotating with the asteroid, and the stable frozen orbits with argument of perigee librating around values different from 0°, 90°, 180°, 270°.

  3. Existence of Periodic Orbits with Zeno Behavior in Completed Lagrangian Hybrid Systems

    OpenAIRE

    Or, Yizhar; Ames, Aaron D.

    2009-01-01

    In this paper, we consider hybrid models of mechanical systems undergoing impacts, Lagrangian hybrid systems, and study their periodic orbits in the presence of Zeno behavior-an infinite number of impacts occurring in finite time. The main result of this paper is explicit conditions under which the existence of stable periodic orbits for a Lagrangian hybrid system with perfectly plastic impacts implies the existence of periodic orbits in the same system with non-plastic impacts. Such periodic...

  4. Noise destroys the coexistence of periodic orbits of a piecewise linear map

    International Nuclear Information System (INIS)

    Wang Can-Jun; Yang Ke-Li; Qu Shi-Xian

    2013-01-01

    The effects of Gaussian white noise and Gaussian colored noise on the periodic orbits of period-5 (P-5) and period-6 (P-6) in their coexisting domain of a piecewise linear map are investigated numerically. The probability densities of some orbits are calculated. When the noise intensity is D = 0.0001, only the orbits of P-5 exist, and the coexisting phenomenon is destroyed. On the other hand, the self-correlation time τ of the colored noise also affects the coexisting phenomenon. When τ c c , only the orbits of P-5 appear, and the stability of the orbits of P-5 is enhanced. However, when τ > τ' c (τ c and τ c ' are critical values), only the orbits of P-6 exist, and the stability of the P-6 orbits is enhanced greatly. When τ c , the orbits of P-5 and P-6 coexist, but the stability of the P-5 orbits is enhanced and that of P-6 is weakened with τ increasing

  5. New variational principles for locating periodic orbits of differential equations.

    Science.gov (United States)

    Boghosian, Bruce M; Fazendeiro, Luis M; Lätt, Jonas; Tang, Hui; Coveney, Peter V

    2011-06-13

    We present new methods for the determination of periodic orbits of general dynamical systems. Iterative algorithms for finding solutions by these methods, for both the exact continuum case, and for approximate discrete representations suitable for numerical implementation, are discussed. Finally, we describe our approach to the computation of unstable periodic orbits of the driven Navier-Stokes equations, simulated using the lattice Boltzmann equation.

  6. Non-linear vibrational modes in biomolecules: A periodic orbits description

    International Nuclear Information System (INIS)

    Kampanarakis, Alexandros; Farantos, Stavros C.; Daskalakis, Vangelis; Varotsis, Constantinos

    2012-01-01

    Graphical abstract: Vibrational frequency shifts in Fe IV = O species of the active site of cytochrome c oxidase are attributed to changes in the surrounding Coulomb field. Periodic orbits analysis assists to find the most anharmonic modes in model biomolecules. Highlights: ► Periodic orbits are extended to multidimensional potentials of biomolecules. ► Highly anharmonic vibrational modes and center-saddle bifurcations are detected. ► Vibrational frequencies shifts in Oxoferryl species of CcO are observed. - Abstract: The vibrational harmonic normal modes of a molecule, which are valid at energies close to an equilibrium point (a minimum, maximum or saddle of the potential energy surface), are extended by periodic orbits to high energies where anharmonicity and coupling of the degrees of freedom are significant. In this way the assignment of the spectra, and thus the extraction of dynamics in highly excited molecules, can be obtained. New vibrational modes emanating from bifurcations of periodic orbits and long living localized trajectories signal the birth and localization of new quantum states. In this article we review and further study non-linear vibrational modes for model biomolecules such as alanine dipeptide and the active site in the oxoferryl oxidation state of the enzyme cytochrome c oxidase. We locate periodic orbits which exhibit high anhamonicity and lead to center-saddle bifurcations. These modes are associated to an isomerization process in alanine dipeptide and to frequency shifts in the oxoferryl observed by modifying the Coulomb field around the Imidazole–Fe IV = O species.

  7. The incidence of suspected myocardial infarction in Dutch general practice in the period 1978-1994.

    NARCIS (Netherlands)

    Pal-de Bruin, K.M. van der; Verkleij, H.; Jansen, J.; Bartelds, A.; Kromhout, D.

    1998-01-01

    Aim: To evaluate how the incidence of suspected myocardial infarction has developed from 1978 to 1994 and to study the incidence of confirmed acute myocardial infarction in Dutch general practices during the period 1991-1994. Methods: In three periods (1978, 1983-1985 and 1991-1994) the incidence of

  8. About periodic and quasi-periodic orbits of a new type for twist maps of the torus

    Directory of Open Access Journals (Sweden)

    SALVADOR ADDAS-ZANATA

    2002-03-01

    Full Text Available We prove that for a large and important class of C¹ twist maps of the torus periodic and quasi-periodic orbits of a new type exist, provided that there are no rotational invariant circles (R.I.C's. These orbits have a non-zero "vertical rotation number'' (V.R.N., in contrast to what happens to Birkhoff periodic orbits and Aubry-Mather sets. The V.R.N. is rational for a periodic orbit and irrational for a quasi-periodic. We also prove that the existence of an orbit with a V.R.N = a > 0, implies the existence of orbits with V.R.N = b, for all 0 Provamos que para uma relevante classe de aplicações C¹ no toro, que desviam a vertical para a direita, existem órbitas periódicas e quase-periódicas de um novo tipo, se e somente se, não existem círculos rotacionais invariantes. Essas órbitas têm um número de rotação vertical não nulo (N.R.V, em contraste com o que ocorre para órbitas periódicas do tipo Birkhoff e para os conjuntos de Aubry-Mather. O número de rotação vertical é racional para uma órbita periódica e irracional para uma quase-periódica. Também provamos que a existência de uma órbita com N.R.V = a implica a existência de órbitas com N.R.V = b, para todo 0 < b < a. Como consequência destes resultados, obtemos que uma aplicação do toro que desvia a vertical e não possui círculos rotacionais invariates, necessariamente tem entropia topológica positiva, que é um resultado clássico. No fim deste trabalho apresentamos aplicações e exemplos, como o Standard map, dos resultados obtidos.

  9. Periodic orbit-attitude solutions along planar orbits in a perturbed circular restricted three-body problem for the Earth-Moon system

    Science.gov (United States)

    Bucci, Lorenzo; Lavagna, Michèle; Guzzetti, Davide; Howell, Kathleen C.

    2018-06-01

    Interest on Large Space Structures (LSS), orbiting in strategic and possibly long-term stable locations, is nowadays increasing in the space community. LSS can serve as strategic outpost to support a variety of manned and unmanned mission, or may carry scientific payloads for astronomical observations. The paper focuses on analysing LSS in the Earth-Moon system, exploring dynamical structures that are available within a multi-body gravitational environment. Coupling between attitude and orbital dynamics is investigated, with particular interest on the gravity gradient torque exerted by the two massive attractors. First, natural periodic orbit-attitude solutions are obtained; a LSS that exploits such solutions would benefit of a naturally periodic body rotation synchronous with the orbital motion, easing the effort of the attitude control system to satisfy pointing requirements. Then, the solar radiation pressure is introduced into the fully coupled dynamical model and its effects investigated, discovering novel periodic attitude solutions. Benefits of periodic behaviours that incorporate solar radiation pressure are discussed, and analysed via the variation of some parameters (e.g reflection/absorption coefficients, position of the centre of pressure). As a final step to refine the current perturbed orbit-attitude model, a structure flexibility is also superimposed to a reference orbit-attitude rigid body motion via a simple, yet effective model. The coupling of structural vibrations and attitude motion is preliminarily explored, and allows identification of possible challenges, that may be faced to position a LSS in a periodic orbit within the Earth-Moon system.

  10. Quantum-classical correspondence in the vicinity of periodic orbits

    Science.gov (United States)

    Kumari, Meenu; Ghose, Shohini

    2018-05-01

    Quantum-classical correspondence in chaotic systems is a long-standing problem. We describe a method to quantify Bohr's correspondence principle and calculate the size of quantum numbers for which we can expect to observe quantum-classical correspondence near periodic orbits of Floquet systems. Our method shows how the stability of classical periodic orbits affects quantum dynamics. We demonstrate our method by analyzing quantum-classical correspondence in the quantum kicked top (QKT), which exhibits both regular and chaotic behavior. We use our correspondence conditions to identify signatures of classical bifurcations even in a deep quantum regime. Our method can be used to explain the breakdown of quantum-classical correspondence in chaotic systems.

  11. Denjoy minimal sets and Birkhoff periodic orbits for non-exact monotone twist maps

    Science.gov (United States)

    Qin, Wen-Xin; Wang, Ya-Nan

    2018-06-01

    A non-exact monotone twist map φbarF is a composition of an exact monotone twist map φ bar with a generating function H and a vertical translation VF with VF ((x , y)) = (x , y - F). We show in this paper that for each ω ∈ R, there exists a critical value Fd (ω) ≥ 0 depending on H and ω such that for 0 ≤ F ≤Fd (ω), the non-exact twist map φbarF has an invariant Denjoy minimal set with irrational rotation number ω lying on a Lipschitz graph, or Birkhoff (p , q)-periodic orbits for rational ω = p / q. Like the Aubry-Mather theory, we also construct heteroclinic orbits connecting Birkhoff periodic orbits, and show that quasi-periodic orbits in these Denjoy minimal sets can be approximated by periodic orbits. In particular, we demonstrate that at the critical value F =Fd (ω), the Denjoy minimal set is not uniformly hyperbolic and can be approximated by smooth curves.

  12. Test of the periodic-orbit approximation in n-disk systems

    International Nuclear Information System (INIS)

    Wirzba, A.

    1993-01-01

    The scattering of a point particle in two dimensions from two (or three) equally-sized (and spaced) circular hard disks is one of the simplest classically hyperbolic scattering problems. Because of this simplicity such systems are well suited for the study of the semiclassical periodic-orbit approximation in the cycle expansion of the dynamical zeta function applied to a quantum-mechanical scattering problem. Especially the predictions of the semiclassical cycle expansion for the quantum-mechanical resonances can be tested in these n-disk systems. Whereas for high wave numbers the cycle expansion gives quite accurate results, there are systematic deviations for low wave numbers from the exact quantum-mechanical values. The low-lying quantum-mechanical resonance poles of the 2- and 3-disk problem are constructed and compared to the cycle-expansion results. The characteristic determinant of the scattering matrix is expanded in terms of simple traces which in turn are related to the classical periodic orbits and possible creeping contributions. It will be shown that for large separations of the disks the correct resonance-pole positions can be extracted just from the knowledge of the lowest traces whose semiclassical limit are the fundamental periodic orbits. Creeping-orbit corrections are shown to be small. (orig.)

  13. Rigorous Numerics for ill-posed PDEs: Periodic Orbits in the Boussinesq Equation

    Science.gov (United States)

    Castelli, Roberto; Gameiro, Marcio; Lessard, Jean-Philippe

    2018-04-01

    In this paper, we develop computer-assisted techniques for the analysis of periodic orbits of ill-posed partial differential equations. As a case study, our proposed method is applied to the Boussinesq equation, which has been investigated extensively because of its role in the theory of shallow water waves. The idea is to use the symmetry of the solutions and a Newton-Kantorovich type argument (the radii polynomial approach) to obtain rigorous proofs of existence of the periodic orbits in a weighted ℓ1 Banach space of space-time Fourier coefficients with exponential decay. We present several computer-assisted proofs of the existence of periodic orbits at different parameter values.

  14. Periodic orbits and TDHF phase space structure

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Yukio; Iwasawa, Kazuo [Tsukuba Univ., Ibaraki (Japan). Inst. of Physics; Tsukuma, Hidehiko; Sakata, Fumihiko

    1998-03-01

    The collective motion of atomic nuclei is closely coupled with the motion of nucleons, therefore, it is nonlinear, and the contents of the motion change largely with the increase of its amplitude. As the framework which describes the collective motion accompanied by the change of internal structure, time-dependent Hurtley Fock (TDHF) method is suitable. At present, the authors try to make the method for studying the large region structure in quantum system by utilizing the features of the TDHF phase space. The studies made so far are briefed. In this report, the correspondence of the large region patterns appearing in the band structure chart of three-level model with the periodic orbit group in the TDHF phase space is described. The Husimi function is made, and it possesses the information on the form of respective corresponding intrinsic state. The method of making the band structure chart is explained. There are three kinds of the tendency in the intrinsic state group. The E-T charts are made for the band structure charts to quantitatively express the large region tendency. The E-T chart and the T{sub r}-T chart are drawn for a selected characteristic orbit group. It became to be known that the large region properties of the quantum intrinsic state group of three-level model can be forecast by examining the properties of the periodic orbit group in the TDHF phase space. (K.I.)

  15. Nontrivial paths and periodic orbits of the T-fractal billiard table

    Science.gov (United States)

    Lapidus, Michel L.; Miller, Robyn L.; Niemeyer, Robert G.

    2016-07-01

    We introduce and prove numerous new results about the orbits of the T-fractal billiard. Specifically, in section 3, we give a variety of sufficient conditions for the existence of a sequence of compatible periodic orbits. In section 4, we examine the limiting behavior of particular sequences of compatible periodic orbits. Additionally, sufficient conditions for the existence of particular nontrivial paths are given in section 4. The proofs of two results of Lapidus and Niemeyer (2013 The current state of fractal billiards Fractal Geometry and Dynamical Systems in Pure and Applied Mathematics II: Fractals in Applied Mathematics (Contemporary Mathematics vol 601) ed D Carfi et al (Providence, RI: American Mathematical Society) pp 251-88 (e-print: arXiv:math.DS.1210.0282v2, 2013) appear here for the first time, as well. In section 5, an orbit with an irrational initial direction reaches an elusive point in a way that yields a nontrivial path of finite length, yet, by our convention, constitutes a singular orbit of the fractal billiard table. The existence of such an orbit seems to indicate that the classification of orbits may not be so straightforward. A discussion of our results and directions for future research is then given in section 6.

  16. Periodic orbits of solar sail equipped with reflectance control device in Earth-Moon system

    Science.gov (United States)

    Yuan, Jianping; Gao, Chen; Zhang, Junhua

    2018-02-01

    In this paper, families of Lyapunov and halo orbits are presented with a solar sail equipped with a reflectance control device in the Earth-Moon system. System dynamical model is established considering solar sail acceleration, and four solar sail steering laws and two initial Sun-sail configurations are introduced. The initial natural periodic orbits with suitable periods are firstly identified. Subsequently, families of solar sail Lyapunov and halo orbits around the L1 and L2 points are designed with fixed solar sail characteristic acceleration and varying reflectivity rate and pitching angle by the combination of the modified differential correction method and continuation approach. The linear stabilities of solar sail periodic orbits are investigated, and a nonlinear sliding model controller is designed for station keeping. In addition, orbit transfer between the same family of solar sail orbits is investigated preliminarily to showcase reflectance control device solar sail maneuver capability.

  17. Stabilizing periodic orbits of chaotic systems using fuzzy adaptive sliding mode control

    Energy Technology Data Exchange (ETDEWEB)

    Layeghi, Hamed [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: layeghi@mech.sharif.edu; Arjmand, Mehdi Tabe [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: arjmand@mech.sharif.edu; Salarieh, Hassan [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

    2008-08-15

    In this paper by using a combination of fuzzy identification and the sliding mode control a fuzzy adaptive sliding mode scheme is designed to stabilize the unstable periodic orbits of chaotic systems. The chaotic system is assumed to have an affine form x{sup (n)} = f(X) + g(X)u where f and g are unknown functions. Using only the input-output data obtained from the underlying dynamical system, two fuzzy systems are constructed for identification of f and g. Two distinct methods are utilized for fuzzy modeling, the least squares and the gradient descent techniques. Based on the estimated fuzzy models, an adaptive controller, which works through the sliding mode control, is designed to make the system track the desired unstable periodic orbits. The stability analysis of the overall closed loop system is presented in the paper and the effectiveness of the proposed adaptive scheme is numerically investigated. As a case of study, modified Duffing system is selected for applying the proposed method to stabilize its 2{pi} and 4{pi} periodic orbits. Simulation results show the high performance of the method for stabilizing the unstable periodic orbits of unknown chaotic systems.

  18. Periodic orbits of hybrid systems and parameter estimation via AD

    International Nuclear Information System (INIS)

    Guckenheimer, John; Phipps, Eric Todd; Casey, Richard

    2004-01-01

    Rhythmic, periodic processes are ubiquitous in biological systems; for example, the heart beat, walking, circadian rhythms and the menstrual cycle. Modeling these processes with high fidelity as periodic orbits of dynamical systems is challenging because: (1) (most) nonlinear differential equations can only be solved numerically; (2) accurate computation requires solving boundary value problems; (3) many problems and solutions are only piecewise smooth; (4) many problems require solving differential-algebraic equations; (5) sensitivity information for parameter dependence of solutions requires solving variational equations; and (6) truncation errors in numerical integration degrade performance of optimization methods for parameter estimation. In addition, mathematical models of biological processes frequently contain many poorly-known parameters, and the problems associated with this impedes the construction of detailed, high-fidelity models. Modelers are often faced with the difficult problem of using simulations of a nonlinear model, with complex dynamics and many parameters, to match experimental data. Improved computational tools for exploring parameter space and fitting models to data are clearly needed. This paper describes techniques for computing periodic orbits in systems of hybrid differential-algebraic equations and parameter estimation methods for fitting these orbits to data. These techniques make extensive use of automatic differentiation to accurately and efficiently evaluate derivatives for time integration, parameter sensitivities, root finding and optimization. The boundary value problem representing a periodic orbit in a hybrid system of differential algebraic equations is discretized via multiple-shooting using a high-degree Taylor series integration method (GM00, Phi03). Numerical solutions to the shooting equations are then estimated by a Newton process yielding an approximate periodic orbit. A metric is defined for computing the distance

  19. On the observed excess of retrograde orbits among long-period comets

    International Nuclear Information System (INIS)

    Fernandez, J.A.

    1981-01-01

    The distribution of orbital inclinations of the observed long-period comets is analysed. An excess of retrograde orbits is found which increases with the perihelion distance, except for the range 1.1 10 3 A U) has the same behaviour as the total sample. It is thus suggested that the excess of retrograde orbits among long-period comets is related to an already existent excess among the incoming new comets (i.e. comets driven into the planetary region by stellar perturbations). Using theoretical considerations and a numerical model it is proposed that an important fraction of the so-called new comets are actually repeating passages through the planetary region. Nearly a half of the new comets with q > 2 A U may be repeating passages. An important consequence of the presence of comets repeating passages among the new ones is the production of an excess of retrograde orbits in the whole sample. (author)

  20. Orbital motion in pre-main sequence binaries

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, G. H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Prato, L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Simon, M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Patience, J., E-mail: schaefer@chara-array.org [Astrophysics Group, School of Physics, University of Exeter, Exeter, EX4 4QL (United Kingdom)

    2014-06-01

    We present results from our ongoing program to map the visual orbits of pre-main sequence (PMS) binaries in the Taurus star forming region using adaptive optics imaging at the Keck Observatory. We combine our results with measurements reported in the literature to analyze the orbital motion for each binary. We present preliminary orbits for DF Tau, T Tau S, ZZ Tau, and the Pleiades binary HBC 351. Seven additional binaries show curvature in their relative motion. Currently, we can place lower limits on the orbital periods for these systems; full solutions will be possible with more orbital coverage. Five other binaries show motion that is indistinguishable from linear motion. We suspect that these systems are bound and might show curvature with additional measurements in the future. The observations reported herein lay critical groundwork toward the goal of measuring precise masses for low-mass PMS stars.

  1. Targeting Ballistic Lunar Capture Trajectories Using Periodic Orbits in the Sun-Earth CRTBP

    Science.gov (United States)

    Cooley, D.S.; Griesemer, Paul Ricord; Ocampo, Cesar

    2009-01-01

    A particular periodic orbit in the Earth-Sun circular restricted three body problem is shown to have the characteristics needed for a ballistic lunar capture transfer. An injection from a circular parking orbit into the periodic orbit serves as an initial guess for a targeting algorithm. By targeting appropriate parameters incrementally in increasingly complicated force models and using precise derivatives calculated from the state transition matrix, a reliable algorithm is produced. Ballistic lunar capture trajectories in restricted four body systems are shown to be able to be produced in a systematic way.

  2. Long-term orbital period behaviour of low mass ratio contact binaries GR Vir and FP Boo

    Science.gov (United States)

    Ćetinkaya, Halil; Soydugan, Faruk

    2017-02-01

    In this study, we investigated orbital period variations of two low mass ratio contact binaries GR Vir and FP Boo based on published minima times. From the O-C analysis, it was found that FP Boo indicates orbital period decrease while the period of GR Vir is increasing. Mass transfer process was used to explain increase and decrease in the orbital periods. In the O-C diagrams of both systems periodic variations also exist. Cyclic changes can be explained as being the result of a light-travel time effect via a third component around the eclipsing binaries. In order to interpret of cyclic orbital period changes for GR Vir, which has late-type components, possible magnetic activity cycles of the components have been also considered.

  3. Accumulation of unstable periodic orbits and the stickiness in the two-dimensional piecewise linear map.

    Science.gov (United States)

    Akaishi, A; Shudo, A

    2009-12-01

    We investigate the stickiness of the two-dimensional piecewise linear map with a family of marginal unstable periodic orbits (FMUPOs), and show that a series of unstable periodic orbits accumulating to FMUPOs plays a significant role to give rise to the power law correlation of trajectories. We can explicitly specify the sticky zone in which unstable periodic orbits whose stability increases algebraically exist, and find that there exists a hierarchy in accumulating periodic orbits. In particular, the periodic orbits with linearly increasing stability play the role of fundamental cycles as in the hyperbolic systems, which allows us to apply the method of cycle expansion. We also study the recurrence time distribution, especially discussing the position and size of the recurrence region. Following the definition adopted in one-dimensional maps, we show that the recurrence time distribution has an exponential part in the short time regime and an asymptotic power law part. The analysis on the crossover time T(c)(*) between these two regimes implies T(c)(*) approximately -log[micro(R)] where micro(R) denotes the area of the recurrence region.

  4. Analysis of Periodic Orbits about the Triangular Solutions of the Restricted Sum-Jupiter and Earth-Moon Problem

    Directory of Open Access Journals (Sweden)

    Sang-Young Park

    1988-12-01

    Full Text Available Using the numerical solution in the plane restricted problem of three bodies, about 490 periodic orbits are computed numerically around the L5 of Sun-Jupiter and about 1600 periodic orbits also be done around the L5 of Earth-Moon system. As period increase, the energy and the shape of periodic orbits increase around the L5 of Sun-Jupiter system. But, in Earth-Moon system, the complex shapes and dents appear around the L5 and periodic orbits intersect one another in the place where dents are shown. And there is a region that three different periodic orbits exist with the same period in this region. The regions can exist around the L5 of Sun-Jupiter system where periodic orbit can be unstable by perturbation of other force besides the gravitational force of Jupiter. These regions which is close to L5 are a ~5.12 AU and a ~5.29 AU. The Trojan asteroids that have a small eccentricity and inclination can not exist in this region.

  5. The shortest-known-period star orbiting our Galaxy's supermassive black hole.

    Science.gov (United States)

    Meyer, L; Ghez, A M; Schödel, R; Yelda, S; Boehle, A; Lu, J R; Do, T; Morris, M R; Becklin, E E; Matthews, K

    2012-10-05

    Stars with short orbital periods at the center of our Galaxy offer a powerful probe of a supermassive black hole. Over the past 17 years, the W. M. Keck Observatory has been used to image the galactic center at the highest angular resolution possible today. By adding to this data set and advancing methodologies, we have detected S0-102, a star orbiting our Galaxy's supermassive black hole with a period of just 11.5 years. S0-102 doubles the number of known stars with full phase coverage and periods of less than 20 years. It thereby provides the opportunity, with future measurements, to resolve degeneracies in the parameters describing the central gravitational potential and to test Einstein's theory of general relativity in an unexplored regime.

  6. An existence proof of a symmetric periodic orbit in the octahedral six-body problem

    OpenAIRE

    Cavalcanti, Anete Soares

    2016-01-01

    We present a proof of the existence of a periodic orbit for the Newtonian six-body problem with equal masses. This orbit has three double collisions each period and no multiple collisions. Our proof is based on the minimization of the Lagrangian action functional on a well chosen class of symmetric loops.

  7. A 12 MINUTE ORBITAL PERIOD DETACHED WHITE DWARF ECLIPSING BINARY

    International Nuclear Information System (INIS)

    Brown, Warren R.; Kilic, Mukremin; Kenyon, Scott J.; Hermes, J. J.; Winget, D. E.; Prieto, Carlos Allende

    2011-01-01

    We have discovered a detached pair of white dwarfs (WDs) with a 12.75 minute orbital period and a 1315 km s -1 radial velocity amplitude. We measure the full orbital parameters of the system using its light curve, which shows ellipsoidal variations, Doppler boosting, and primary and secondary eclipses. The primary is a 0.25 M sun tidally distorted helium WD, only the second tidally distorted WD known. The unseen secondary is a 0.55 M sun carbon-oxygen WD. The two WDs will come into contact in 0.9 Myr due to loss of energy and angular momentum via gravitational wave radiation. Upon contact the systems may merge (yielding a rapidly spinning massive WD), form a stable interacting binary, or possibly explode as an underluminous Type Ia supernova. The system currently has a gravitational wave strain of 10 -22 , about 10,000 times larger than the Hulse-Taylor pulsar; this system would be detected by the proposed Laser Interferometer Space Antenna gravitational wave mission in the first week of operation. This system's rapid change in orbital period will provide a fundamental test of general relativity.

  8. A Simple Time Domain Collocation Method to Precisely Search for the Periodic Orbits of Satellite Relative Motion

    Directory of Open Access Journals (Sweden)

    Xiaokui Yue

    2014-01-01

    Full Text Available A numerical approach for obtaining periodic orbits of satellite relative motion is proposed, based on using the time domain collocation (TDC method to search for the periodic solutions of an exact J2 nonlinear relative model. The initial conditions for periodic relative orbits of the Clohessy-Wiltshire (C-W equations or Tschauner-Hempel (T-H equations can be refined with this approach to generate nearly bounded orbits. With these orbits, a method based on the least-squares principle is then proposed to generate projected closed orbit (PCO, which is a reference for the relative motion control. Numerical simulations reveal that the presented TDC searching scheme is effective and simple, and the projected closed orbit is very fuel saving.

  9. Orbital stability of periodic traveling-wave solutions for the log-KdV equation

    Science.gov (United States)

    Natali, Fábio; Pastor, Ademir; Cristófani, Fabrício

    2017-09-01

    In this paper we establish the orbital stability of periodic waves related to the logarithmic Korteweg-de Vries equation. Our motivation is inspired in the recent work [3], in which the authors established the well-posedness and the linear stability of Gaussian solitary waves. By using the approach put forward recently in [20] to construct a smooth branch of periodic waves as well as to get the spectral properties of the associated linearized operator, we apply the abstract theories in [13] and [25] to deduce the orbital stability of the periodic traveling waves in the energy space.

  10. An exact solution for orbit view-periods from a station on a tri-axial ellipsoidal planet

    Science.gov (United States)

    Tang, C. C. H.

    1986-01-01

    This paper presents the concise exact solution for predicting view-periods to be observed from a masked or unmasked tracking station on a tri-axial ellipsoidal surface. The new exact approach expresses the azimuth and elevation angles of a spacecraft in terms of the station-centered geodetic topocentric coordinates in an elegantly concise manner. A simple and efficient algorithm is developed to avoid costly repetitive computations in searching for neighborhoods near the rise and set times of each satellite orbit for each station. Only one search for each orbit is necessary for each station. Sample results indicate that the use of an assumed spherical earth instead of an 'actual' tri-axial ellipsoidal earth could introduce an error up to a few minutes in a view-period prediction for circular orbits of low or medium altitude. For an elliptical orbit of high eccentricity and long period, the maximum error could be even larger. The analytic treatment and the efficient algorithm are designed for geocentric orbits, but they should be applicable to interplanetary trajectories by an appropriate coordinates transformation at each view-period calculation. This analysis can be accomplished only by not using the classical orbital elements.

  11. An exact solution for orbit view-periods from a station on a tri-axial ellipsoidal planet

    Science.gov (United States)

    Tang, C. C. H.

    1986-08-01

    This paper presents the concise exact solution for predicting view-periods to be observed from a masked or unmasked tracking station on a tri-axial ellipsoidal surface. The new exact approach expresses the azimuth and elevation angles of a spacecraft in terms of the station-centered geodetic topocentric coordinates in an elegantly concise manner. A simple and efficient algorithm is developed to avoid costly repetitive computations in searching for neighborhoods near the rise and set times of each satellite orbit for each station. Only one search for each orbit is necessary for each station. Sample results indicate that the use of an assumed spherical earth instead of an 'actual' tri-axial ellipsoidal earth could introduce an error up to a few minutes in a view-period prediction for circular orbits of low or medium altitude. For an elliptical orbit of high eccentricity and long period, the maximum error could be even larger. The analytic treatment and the efficient algorithm are designed for geocentric orbits, but they should be applicable to interplanetary trajectories by an appropriate coordinates transformation at each view-period calculation. This analysis can be accomplished only by not using the classical orbital elements.

  12. The puzzling orbital period evolution of the LMXB AX J1745.6-2901

    Science.gov (United States)

    Ponti, G.; De, K.; Munoz-Darias, T.; Stella, L.; Nandra, K.

    2017-10-01

    The discovery of gravitational waves through mergers of binary black holes raises the question of how such compact systems form, renewing issues related to the orbital evolution of binary systems. Eclipsing X-ray binaries are excellent tools to constrain the orbital period evolution and how the system loses angular momentum. I will present an X-ray eclipse timing analysis (spanning an interval of more than 20 yr) of one of such objects, AX J1745.6-2901. Its orbital period is decreasing at a rate Pdotorb=-4.03+-0.32 e-11 s s-1, at least one order of magnitude larger than expected from conservative mass transfer and angular momentum losses due to gravitational waves and magnetic braking, and it might result from either non-conservative mass transfer or magnetic activity changing the quadrupole moment of the companion star. I will also show that imprinted on the long-term evolution of the orbit, there are highly significant eclipse leads delays of 10-30 s, characterized by a clear state dependence in which, on average, eclipses occur earlier during the hard state. Finally, I will discuss whether accretion disc winds might have an impact onto the orbital evolution.

  13. Detecting a Subsurface Ocean From Periodic Orbits at Enceladus

    Science.gov (United States)

    Casotto, S.; Padovan, S.; Russell, R. P.; Lara, M.

    2008-12-01

    from the tiger- stripes. Near-circular, low altitude highly inclined orbits with arbitrary initial conditions will impact Enceladus if uncontrolled in about 1 to 2 days. To reduce risk and station-keeping requirements we choose periodic orbits in the Hill's plus non-spherical Enceladus model. Despite the instability, the repeat ground track solutions represent equilibria in the dominant terms of the dynamics and therefore extend the uncontrolled lifetimes to ~7 to ~10 days. Round-trip transfers between the two orbital phases is expected to conservatively cost between ~50 and ~100 m/s. We use orbits of different altitudes and inclinations to simulate Earth-based ranging to the orbiter and altimeter measurements to the surface of Enceladus. The simulations are made assuming different tidal responses by adopting different values of the Love numbers. The synthetic measurements are then inverted and the tidal parameters h2 and k2 estimated. Results will be presented in terms of sensitivity of detection of Love numbers to the different orbital geometries. Indications will thus be provided for optimized orbit planning of future exploration missions aimed at investigating the internal structure of the satellite and the detection of its putative subcrustal ocean.

  14. The first orbital parameters and period variation of the short-period eclipsing binary AQ Boo

    Science.gov (United States)

    Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn

    2016-10-01

    We obtained the first VRI CCD light curves of the short-period contact eclipsing binary AQ Boo, which was observed on March 22 and April 19 in 2014 at Xinglong station of National Astronomical Observatories, and on January 20, 21 and February 28 in 2015 at Kunming station of Yunnan Observatories of Chinese Academy of Sciences, China. Using our six newly obtained minima and the minima that other authors obtained previously, we revised the ephemeris of AQ Boo. By fitting the O-C (observed minus calculated) values of the minima, the orbital period of AQ Boo shows a decreasing tendency P˙ = - 1.47(0.17) ×10-7 days/year. We interpret the phenomenon by mass transfer from the secondary (more massive) component to the primary (less massive) one. By using the updated Wilson & Devinney program, we also derived the photometric orbital parameters of AQ Boo for the first time. We conclude that AQ Boo is a near contact binary with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.

  15. The Effect of Seasonal and Long-Period Geopotential Variations on the GPS Orbits

    Science.gov (United States)

    Melachroinos, Stavros A.; Lemoine, Frank G.; Chinn, Douglas S.; Zelensky, Nikita P.; Nicholas, Joseph B.; Beckley, Brian D.

    2013-01-01

    We examine the impact of using seasonal and long-period time-variable gravity field (TVG) models on GPS orbit determination, through simulations from 1994 to 2012. The models of time-variable gravity that we test include the GRGS release RL02 GRACE-derived 10-day gravity field models up to degree and order 20 (grgs20x20), a 4 x 4 series of weekly coefficients using GGM03S as a base derived from SLR and DORIS tracking to 11 satellites (tvg4x4), and a harmonic fit to the above 4 x 4 SLR-DORIS time series (goco2s_fit2). These detailed models are compared to GPS orbit simulations using a reference model (stdtvg) based on the International Earth Rotation Service (IERS) and International GNSS Service (IGS) repro1 standards. We find that the new TVG modeling produces significant along, cross-track orbit differences as well as annual, semi-annual, draconitic and long-period effects in the Helmert translation parameters (Tx, Ty, Tz) of the GPS orbits with magnitudes of several mm. We show that the simplistic TVG modeling approach used by all of the IGS Analysis Centers, which is based on the models provided by the IERS standards, becomes progressively less adequate following 2006 when compared to the seasonal and long-period TVG models.

  16. Localization of periodic orbits of polynomial vector fields of even degree by linear functions

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, Konstantin E. [CITEDI-IPN, Av. del Parque 1310, Mesa de Otay, Tijuana, BC (Mexico)] e-mail: konst@citedi.mx

    2005-08-01

    This paper is concerned with the localization problem of periodic orbits of polynomial vector fields of even degree by using linear functions. Conditions of the localization of all periodic orbits in sets of a simple structure are obtained. Our results are based on the solution of the conditional extremum problem and the application of homogeneous polynomial forms of even degrees. As examples, the Lanford system, the jerky system with one quadratic monomial and a quartically perturbed harmonic oscillator are considered.

  17. Localization of periodic orbits of polynomial vector fields of even degree by linear functions

    International Nuclear Information System (INIS)

    Starkov, Konstantin E.

    2005-01-01

    This paper is concerned with the localization problem of periodic orbits of polynomial vector fields of even degree by using linear functions. Conditions of the localization of all periodic orbits in sets of a simple structure are obtained. Our results are based on the solution of the conditional extremum problem and the application of homogeneous polynomial forms of even degrees. As examples, the Lanford system, the jerky system with one quadratic monomial and a quartically perturbed harmonic oscillator are considered

  18. Role of short periodic orbits in quantum maps with continuous openings

    Science.gov (United States)

    Prado, Carlos A.; Carlo, Gabriel G.; Benito, R. M.; Borondo, F.

    2018-04-01

    We apply a recently developed semiclassical theory of short periodic orbits to the continuously open quantum tribaker map. In this paradigmatic system the trajectories are partially bounced back according to continuous reflectivity functions. This is relevant in many situations that include optical microresonators and more complicated boundary conditions. In a perturbative regime, the shortest periodic orbits belonging to the classical repeller of the open map—a cantor set given by a region of exactly zero reflectivity—prove to be extremely robust in supporting a set of long-lived resonances of the continuously open quantum maps. Moreover, for steplike functions a significant reduction in the number needed is obtained, similarly to the completely open situation. This happens despite a strong change in the spectral properties when compared to the discontinuous reflectivity case. In order to give a more realistic interpretation of these results we compare with a Fresnel-type reflectivity function.

  19. Localization of periodic orbits of the Roessler system under variation of its parameters

    International Nuclear Information System (INIS)

    Starkov, Konstantin E.; Starkov, Konstantin K.

    2007-01-01

    The localization problem of compact invariant sets of the Roessler system is considered in this paper. The main interest is attracted to a localization of periodic orbits. We establish a number of algebraic conditions imposed on parameters under which the Roessler system has no compact invariant sets contained in half-spaces z > 0; z < 0 and in some others. We prove that if parameters (a, b, c) of the Roessler system are such that this system has no equilibrium points then it has no periodic orbits as well. In addition, we give localization conditions of compact invariant sets by using linear functions and one quadratic function

  20. Localization of periodic orbits of the Roessler system under variation of its parameters

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, Konstantin E. [CITEDI-IPN, Av. del Parque 1310, Mesa de Otay, Tijuana, BC (Mexico)]. E-mail: konst@citedi.mx; Starkov, Konstantin K. [UABC - Campus Tijuana, Facultad de Ciencias Quimicas e Ingenieria, Calzada Tecnologico, Mesa de Otay, Tijuana, BC (Mexico)

    2007-08-15

    The localization problem of compact invariant sets of the Roessler system is considered in this paper. The main interest is attracted to a localization of periodic orbits. We establish a number of algebraic conditions imposed on parameters under which the Roessler system has no compact invariant sets contained in half-spaces z > 0; z < 0 and in some others. We prove that if parameters (a, b, c) of the Roessler system are such that this system has no equilibrium points then it has no periodic orbits as well. In addition, we give localization conditions of compact invariant sets by using linear functions and one quadratic function.

  1. Modeling and analysis of periodic orbits around a contact binary asteroid

    NARCIS (Netherlands)

    Feng, J.; Noomen, R.; Visser, P.N.A.M.; Yuan, J.

    2015-01-01

    The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is

  2. The orbital period in the supergiant fast X-ray transient IGR J16465--4507

    OpenAIRE

    Clark, D. J.; Sguera, V.; Bird, A. J; McBride, V. A.; Hill, A. B.; Scaringi, S.; Drave, S.; Bazzano, A.; Dean, A. J

    2010-01-01

    Timing analysis of the INTEGRAL-IBIS and Swift-BAT light curves of the Supergiant Fast X-ray Transient (SFXT) IGR J16465-4507 has identified a period of 30.32+/-0.02 days which we interpret as the orbital period of the binary system. In addition 11 outbursts (9 of which are previously unpublished) have been found between MJD 52652 to MJD 54764, all of which occur close to the region of the orbit we regard as periastron. From the reported flux outbursts, we found a dynamical range in the inter...

  3. Localization of periodic orbits of polynomial systems by ellipsoidal estimates

    International Nuclear Information System (INIS)

    Starkov, Konstantin E.; Krishchenko, Alexander P.

    2005-01-01

    In this paper we study the localization problem of periodic orbits of multidimensional continuous-time systems in the global setting. Our results are based on the solution of the conditional extremum problem and using sign-definite quadratic and quartic forms. As examples, the Rikitake system and the Lamb's equations for a three-mode operating cavity in a laser are considered

  4. Localization of periodic orbits of polynomial systems by ellipsoidal estimates

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, Konstantin E. [CITEDI-IPN, Avenue del Parque 1310, Mesa de Otay, Tijuana, BC (Mexico)]. E-mail: konst@citedi.mx; Krishchenko, Alexander P. [Bauman Moscow State Technical University, 2nd Baumanskaya Street, 5, Moscow 105005 (Russian Federation)]. E-mail: apkri@999.ru

    2005-02-01

    In this paper we study the localization problem of periodic orbits of multidimensional continuous-time systems in the global setting. Our results are based on the solution of the conditional extremum problem and using sign-definite quadratic and quartic forms. As examples, the Rikitake system and the Lamb's equations for a three-mode operating cavity in a laser are considered.

  5. Characteristics of persistent spin current components in a quasi-periodic Fibonacci ring with spin–orbit interactions: Prediction of spin–orbit coupling and on-site energy

    International Nuclear Information System (INIS)

    Patra, Moumita; Maiti, Santanu K.

    2016-01-01

    In the present work we investigate the behavior of all three components of persistent spin current in a quasi-periodic Fibonacci ring subjected to Rashba and Dresselhaus spin–orbit interactions. Analogous to persistent charge current in a conducting ring where electrons gain a Berry phase in presence of magnetic flux, spin Berry phase is associated during the motion of electrons in presence of a spin–orbit field which is responsible for the generation of spin current. The interplay between two spin–orbit fields along with quasi-periodic Fibonacci sequence on persistent spin current is described elaborately, and from our analysis, we can estimate the strength of any one of two spin–orbit couplings together with on-site energy, provided the other is known. - Highlights: • Determination of Rashba and Dresselhaus spin–orbit fields is discussed. • Characteristics of all three components of spin current are explored. • Possibility of estimating on-site energy is given. • Results can be generalized to any lattice models.

  6. Characteristics of persistent spin current components in a quasi-periodic Fibonacci ring with spin–orbit interactions: Prediction of spin–orbit coupling and on-site energy

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Moumita; Maiti, Santanu K., E-mail: santanu.maiti@isical.ac.in

    2016-12-15

    In the present work we investigate the behavior of all three components of persistent spin current in a quasi-periodic Fibonacci ring subjected to Rashba and Dresselhaus spin–orbit interactions. Analogous to persistent charge current in a conducting ring where electrons gain a Berry phase in presence of magnetic flux, spin Berry phase is associated during the motion of electrons in presence of a spin–orbit field which is responsible for the generation of spin current. The interplay between two spin–orbit fields along with quasi-periodic Fibonacci sequence on persistent spin current is described elaborately, and from our analysis, we can estimate the strength of any one of two spin–orbit couplings together with on-site energy, provided the other is known. - Highlights: • Determination of Rashba and Dresselhaus spin–orbit fields is discussed. • Characteristics of all three components of spin current are explored. • Possibility of estimating on-site energy is given. • Results can be generalized to any lattice models.

  7. Supporting a Deep Space Gateway with Free-Return Earth-Moon Periodic Orbits

    Science.gov (United States)

    Genova, A. L.; Dunham, D. W.; Hardgrove, C.

    2018-02-01

    Earth-Moon periodic orbits travel between the Earth and Moon via free-return circumlunar segments and can host a station that can provide architecture support to other nodes near the Moon and Mars while enabling science return from cislunar space.

  8. TRANSITING PLANETS WITH LSST. II. PERIOD DETECTION OF PLANETS ORBITING 1 M{sub ⊙} HOSTS

    Energy Technology Data Exchange (ETDEWEB)

    Jacklin, Savannah [Department of Astrophysics and Planetary Science, Villanova University, Villanova, PA 19085 (United States); Lund, Michael B.; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Pepper, Joshua [Department of Physics, Lehigh University, Bethlehem, PA 18015 (United States)

    2015-07-15

    The Large Synoptic Survey Telescope (LSST) will photometrically monitor ∼10{sup 9} stars for 10 years. The resulting light curves can be used to detect transiting exoplanets. In particular, as demonstrated by Lund et al., LSST will probe stellar populations currently undersampled in most exoplanet transit surveys, including out to extragalactic distances. In this paper we test the efficiency of the box-fitting least-squares (BLS) algorithm for accurately recovering the periods of transiting exoplanets using simulated LSST data. We model planets with a range of radii orbiting a solar-mass star at a distance of 7 kpc, with orbital periods ranging from 0.5 to 20 days. We find that standard-cadence LSST observations will be able to reliably recover the periods of Hot Jupiters with periods shorter than ∼3 days; however, it will remain a challenge to confidently distinguish these transiting planets from false positives. At the same time, we find that the LSST deep-drilling cadence is extremely powerful: the BLS algorithm successfully recovers at least 30% of sub-Saturn-size exoplanets with orbital periods as long as 20 days, and a simple BLS power criterion robustly distinguishes ∼98% of these from photometric (i.e., statistical) false positives.

  9. The ω-limit sets of a flow and periodic orbits

    International Nuclear Information System (INIS)

    Wang Xiaoxia; Blackmore, Denis; Wang Chengwen

    2009-01-01

    In this paper we discuss the ω-limit sets of a flow using the Conley theory, chain recurrence and Morse decompositions. Our results generalize and improve the related result in [Schropp J. A reduction principle for ω-limit sets. Z Angew Math Meth 1996;76(6):349-56], and we also show how they can be used as a basis for some new criteria for the existence of periodic orbits.

  10. Orbital period changes in RW CrA, DX Vel and V0646 Cen

    Science.gov (United States)

    Volkov, I. M.; Chochol, D.; Grygar, J.; Mašek, M.; Juryšek, J.

    2017-06-01

    We aim to determine the absolute parameters of the components of southern Algol-type binaries with deep eclipses RW CrA, DX Vel, V0646 Cen and interpret their orbital period changes. The data analysis is based on a high quality Walraven photoelectric photometry, obtained in the 1960-70s, our recent CCD photometry, ASAS (Pojmanski, 2002), and Hipparcos (Perryman et al., 1997) photometry of the objects. Their light curves were analyzed using the PHOEBE program with fixed effective temperatures of the primary components, found from disentangling the Walraven (B-U) and (V-B) colour indices. We found the absolute parameters of the components of all three objects. All reliable observed times of minimum light were used to construct and analyze the Eclipse Time Variation (ETV) diagrams. We interpreted the ETV diagrams of the detached binary RW CrA and the semi-detached binary DX Vel by a LIght-Time Effect (LITE), estimated parameters of their orbits and masses of their third bodies. We suggest a long term variation of the inclination angle of both eclipsing binaries, caused by a non-coplanar orientation of their third body orbits. We interpreted the detected orbital period increase in the semi-detached binary V0646 Cen by a mass transfer from the less to more massive component with the rate M⊙ = 6.08×10-9 M⊙/yr.

  11. Families of periodic orbits in Hill's problem with solar radiation pressure: application to Hayabusa 2

    Science.gov (United States)

    Giancotti, Marco; Campagnola, Stefano; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

    2014-11-01

    This work studies periodic solutions applicable, as an extended phase, to the JAXA asteroid rendezvous mission Hayabusa 2 when it is close to target asteroid 1999 JU3. The motion of a spacecraft close to a small asteroid can be approximated with the equations of Hill's problem modified to account for the strong solar radiation pressure. The identification of families of periodic solutions in such systems is just starting and the field is largely unexplored. We find several periodic orbits using a grid search, then apply numerical continuation and bifurcation theory to a subset of these to explore the changes in the orbit families when the orbital energy is varied. This analysis gives information on their stability and bifurcations. We then compare the various families on the basis of the restrictions and requirements of the specific mission considered, such as the pointing of the solar panels and instruments. We also use information about their resilience against parameter errors and their ground tracks to identify one particularly promising type of solution.

  12. Mean Orbital Elements for Geosynchronous Orbit - II - Orbital inclination, longitude of ascending node, mean longitude

    Directory of Open Access Journals (Sweden)

    Kyu-Hong Choi

    1990-06-01

    Full Text Available The osculating orbital elements include the mean, secular, long period, and short period terms. The iterative algorithm used for conversion of osculating orbital elements to mean orbital elements is described. The mean orbital elements of Wc, Ws, and L are obtained.

  13. More than six hundred new families of Newtonian periodic planar collisionless three-body orbits

    Science.gov (United States)

    Li, XiaoMing; Liao, ShiJun

    2017-12-01

    The famous three-body problem can be traced back to Isaac Newton in the 1680s. In the 300 years since this "three-body problem" was first recognized, only three families of periodic solutions had been found, until 2013 when Šuvakov and Dmitrašinović [Phys. Rev. Lett. 110, 114301 (2013)] made a breakthrough to numerically find 13 new distinct periodic orbits, which belong to 11 new families of Newtonian planar three-body problem with equal mass and zero angular momentum. In this paper, we numerically obtain 695 families of Newtonian periodic planar collisionless orbits of three-body system with equal mass and zero angular momentum in case of initial conditions with isosceles collinear configuration, including the well-known figure-eight family found by Moore in 1993, the 11 families found by Šuvakov and Dmitrašinović in 2013, and more than 600 new families that have never been reported, to the best of our knowledge. With the definition of the average period T = T/L f, where L f is the length of the so-called "free group element", these 695 families suggest that there should exist the quasi Kepler's third law T* ≈ 2:433 ± 0:075 for the considered case, where T ≈ = T | E|3/2 is the scale-invariant average period and E is its total kinetic and potential energy, respectively. The movies of these 695 periodic orbits in the real space and the corresponding close curves on the "shape sphere" can be found via the website: http://numericaltank.sjtu.edu.cn/three-body/three-body.htm.

  14. Periodic-orbit theory of the number variance Σ2(L) of strongly chaotic systems

    International Nuclear Information System (INIS)

    Aurich, R.; Steiner, F.

    1994-03-01

    We discuss the number variance Σ 2 (L) and the spectral form factor F(τ) of the energy levels of bound quantum systems whose classical counterparts are strongly chaotic. Exact periodic-orbit representations of Σ 2 (L) and F(τ) are derived which explain the breakdown of universality, i.e., the deviations from the predictions of random-matrix theory. The relation of the exact spectral form factor F(τ) to the commonly used approximation K(τ) is clarified. As an illustration the periodic-orbit representations are tested in the case of a strongly chaotic system at low and high energies including very long-range correlations up to L=700. Good agreement between 'experimental' data and theory is obtained. (orig.)

  15. Orbital Elements and Period Variation of the Eclipsing Binary T LMi

    Directory of Open Access Journals (Sweden)

    Kyu-Dong Oh

    1987-12-01

    Full Text Available A photometric solutions of T LMi were derived with derived with the Wilson and Devinney model using the BV photoelectric light curves of Okazaki(1977 and orbital period changes are discussed from the all of the collected times of minima available in the literature. We obtained a variation with a period of 62.y01 and an amplitude of 0.d0425 form the (O-C diagram. According to the physical properties of T LMi on the basis of derived photometric solution, it have a doubt the credibility of the existence of "R CMs type".

  16. Modeling low-thrust transfers between periodic orbits about five libration points: Manifolds and hierarchical design

    Science.gov (United States)

    Zeng, Hao; Zhang, Jingrui

    2018-04-01

    The low-thrust version of the fuel-optimal transfers between periodic orbits with different energies in the vicinity of five libration points is exploited deeply in the Circular Restricted Three-Body Problem. Indirect optimization technique incorporated with constraint gradients is employed to further improve the computational efficiency and accuracy of the algorithm. The required optimal thrust magnitude and direction can be determined to create the bridging trajectory that connects the invariant manifolds. A hierarchical design strategy dividing the constraint set is proposed to seek the optimal solution when the problem cannot be solved directly. Meanwhile, the solution procedure and the value ranges of used variables are summarized. To highlight the effectivity of the transfer scheme and aim at different types of libration point orbits, transfer trajectories between some sample orbits, including Lyapunov orbits, planar orbits, halo orbits, axial orbits, vertical orbits and butterfly orbits for collinear and triangular libration points, are investigated with various time of flight. Numerical results show that the fuel consumption varies from a few kilograms to tens of kilograms, related to the locations and the types of mission orbits as well as the corresponding invariant manifold structures, and indicates that the low-thrust transfers may be a beneficial option for the extended science missions around different libration points.

  17. Discrete restricted four-body problem: Existence of proof of equilibria and reproducibility of periodic orbits

    Energy Technology Data Exchange (ETDEWEB)

    Minesaki, Yukitaka [Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514 (Japan)

    2015-01-01

    We propose the discrete-time restricted four-body problem (d-R4BP), which approximates the orbits of the restricted four-body problem (R4BP). The d-R4BP is given as a special case of the discrete-time chain regularization of the general N-body problem published in Minesaki. Moreover, we analytically prove that the d-R4BP yields the correct orbits corresponding to the elliptic relative equilibrium solutions of the R4BP when the three primaries form an equilateral triangle at any time. Such orbits include the orbit of a relative equilibrium solution already discovered by Baltagiannis and Papadakis. Until the proof in this work, there has been no discrete analog that preserves the orbits of elliptic relative equilibrium solutions in the R4BP. For a long time interval, the d-R4BP can precisely compute some stable periodic orbits in the Sun–Jupiter–Trojan asteroid–spacecraft system that cannot necessarily be reproduced by other generic integrators.

  18. Orbital fractures due to domestic violence: an epidemiologic study.

    Science.gov (United States)

    Goldberg, Stuart H.; McRill, Connie M.; Bruno, Christopher R.; Ten Have, Tom; Lehman, Erik

    2000-09-01

    Domestic violence is an important cause of orbital fractures in women. Physicians who treat patients with orbital fractures may not suspect this mechanism of injury. The purpose of this study was to assess the association between domestic violence and orbital fractures. A medical center-based case-control study with matching on age and site of admission was done. Medical center databases were searched using ICD-9 codes to identify all cases of orbital fractures encountered during a three-year period. Medical records of female patients age 13 and older were reviewed along with those of age, gender and site of admission matched controls. A stratified exact test was employed to test the association between domestic violence and orbital fracture. Among 41 adult female cases with orbital fractures treated at our medical center, three (7.3%) reported domestic violence compared to zero among the matched controls (p = 0.037). We believe that domestic violence may be under-reported in both orbital fracture cases and controls. This may result in an underestimate of the orbital fracture versus domestic violence association. Domestic violence is a serious women's health and societal problem. Domestic violence may have a variety of presentations, including illnesses and injuries. Orbital fracture is an identifiable manifestation of domestic violence. Domestic violence is more likely to be detected in adult female hospital patients with orbital fracture than in matched controls with any other diagnosis. Physicians who treat patients with orbital fractures should be familiar with this mechanism of injury.

  19. Semiclassical quantization of nonadiabatic systems with hopping periodic orbits

    International Nuclear Information System (INIS)

    Fujii, Mikiya; Yamashita, Koichi

    2015-01-01

    We present a semiclassical quantization condition, i.e., quantum–classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller’s trace formula to a nonadiabatic form. The quantum–classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics

  20. Orbital wall fractures

    International Nuclear Information System (INIS)

    Iinuma, Toshitaka; Ishio, Ken-ichirou; Yoshinami, Hiroyoshi; Kuriyama, Jun-ichi; Hirota, Yoshiharu.

    1993-01-01

    A total of 59 cases of mild facial fractures (simple orbital wall fractures, 34 cases, other facial fractures, 25 cases) with the clinical suspects of orbital wall fractures were evaluated both by conventional views (Waters' and Caldwell views) and coronal CT scans. Conventional views were obtained, as an average, after 4 days and CT after 7 days of injuries. Both the medial wall and the floor were evaluated at two sites, i.e., anterior and posterior. The ethmoid-maxillary plate was also included in the study. The degree of fractures was classified as, no fractures, fractures of discontinuity, dislocation and fragmentation. The coronal CT images in bone window condition was used as reference and the findings were compared between conventional views and CT. The correct diagnosis was obtained as follows: orbital floor (anterior, 78%, posterior, 73%), medial orbital wall (anterior, 72%, posterior, 72%) and ethmoid-maxillary plate (64%). The false positive diagnosis was as follows: orbital floor (anterior only, 13%), medial orbital wall (anterior only, 7%) and ethmoid-maxillary plate (11%). The false negative diagnosis was as follows: orbital floor (anterior, 9%, posterior, 10%), medial orbital wall (anterior, 21%, posterior, 28%) and ethmoid-maxillary plate (21%). The results were compared with those of others in the past. (author)

  1. Existence of periodic orbits in nonlinear oscillators of Emden–Fowler form

    Energy Technology Data Exchange (ETDEWEB)

    Mancas, Stefan C., E-mail: mancass@erau.edu [Department of Mathematics, Embry–Riddle Aeronautical University, Daytona Beach, FL 32114-3900 (United States); Rosu, Haret C., E-mail: hcr@ipicyt.edu.mx [IPICyT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San José 2055, Col. Lomas 4a Sección, 78216 San Luis Potosí, SLP (Mexico)

    2016-01-28

    The nonlinear pseudo-oscillator recently tackled by Gadella and Lara is mapped to an Emden–Fowler (EF) equation that is written as an autonomous two-dimensional ODE system for which we provide the phase-space analysis and the parametric solution. Through an invariant transformation we find periodic solutions to a certain class of EF equations that pass an integrability condition. We show that this condition is necessary to have periodic solutions and via the ODE analysis we also find the sufficient condition for periodic orbits. EF equations that do not pass integrability conditions can be made integrable via an invariant transformation which also allows us to construct periodic solutions to them. Two other nonlinear equations, a zero-frequency Ermakov equation and a positive power Emden–Fowler equation, are discussed in the same context. - Highlights: • An invariant transformation is used to find periodic solution of EF equations. • Phase plane study of the EF autonomous two-dimensional ODE system is performed. • Three examples are presented from the standpoint of the phase plane analysis.

  2. SPECTROSCOPIC ORBITAL PERIODS FOR 29 CATACLYSMIC VARIABLES FROM THE SLOAN DIGITAL SKY SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Thorstensen, John R.; Taylor, Cynthia J.; Peters, Christopher S.; Skinner, Julie N. [Department of Physics and Astronomy 6127 Wilder Laboratory, Dartmouth College Hanover, NH 03755-3528 (United States); Southworth, John [Astrophysics Group Keele University Staffordshire ST5 5BG (United Kingdom); Gänsicke, Boris T. [Department of Physics University of Warwick Coventry CV4 7AL (United Kingdom)

    2015-04-15

    We report follow-up spectroscopy of 29 cataclysmic variables from the Sloan Digital Sky Survey (SDSS), 22 of which were discovered by SDSS and seven of which are previously known systems that were recovered in SDSS. The periods for 16 of these objects were included in the tabulation by Gänsicke et al. While most of the systems have periods less than 2 hr, only one has a period in the 80–86 minutes “spike” found by Gänsicke et al., and 11 have periods longer than 3 hr, indicating that the present sample is skewed toward longer-period, higher-luminosity objects. Seven of the objects have spectra resembling dwarf novae, but have apparently never been observed in outburst, suggesting that many cataclysmics with relatively low variability amplitude remain to be discovered. Some of the objects are notable. SDSS J07568+0858 and SDSS J08129+1911 were previously known to have deep eclipses; in addition to spectroscopy, we use archival data from the Catalina Real Time Transient Survey to refine their periods. We give a parallax-based distance of 195 (+54, −39) pc for LV Cnc (SDSS J09197+0857), which at P{sub orb} = 81 m has the shortest orbital period in our sample. SDSS J08091+3814 shows both the spectroscopic phase offset and phase-dependent absorption found in SW Sextantis stars. The average spectra of SDSS J08055+0720 and SDSS J16191+1351 show contributions from K-type secondaries, and SDSS J080440+0239 shows a contribution from an early M star. We use these to constrain the distances. SDSS J09459+2922 has characteristics typical of a magnetic system. SDSS11324+6249 may be a novalike variable, and if so, its orbital period (99 minutes) is unusually short for that subclass.

  3. Periodicity and chaos in strongly perturbed classical orbitals for Coulomb interactions

    Energy Technology Data Exchange (ETDEWEB)

    Klar, H

    1986-01-01

    Within the framework of classical mechanics two prototypes of strongly perturbed orbitals, the diamagnetism in hydrogen and electronic double excitation, are analyzed near critical phase space points (fixed points). The motion of the hydrogen electron under the joint influence of the Coulomb field and the magnetic field is periodic for any field strengths. For a two-electron atom however the author finds a chaotic time evolution of the electron pair correlation, causing presumably irregular spectral patterns. (Auth.).

  4. Spatial epidemiology of suspected clinical leptospirosis in Sri Lanka.

    Science.gov (United States)

    Robertson, C; Nelson, T A; Stephen, C

    2012-04-01

    Leptospirosis is one of the most widespread zoonoses in the world. A large outbreak of suspected human leptospirosis began in Sri Lanka during 2008. This study investigated spatial variables associated with suspected leptospirosis risk during endemic and outbreak periods. Data were obtained for monthly numbers of reported cases of suspected clinical leptospirosis for 2005-2009 for all of Sri Lanka. Space-time scan statistics were combined with regression modelling to test associations during endemic and outbreak periods. The cross-correlation function was used to test association between rainfall and leptospirosis at four locations. During the endemic period (2005-2007), leptospirosis risk was positively associated with shorter average distance to rivers and with higher percentage of agriculture made up of farms <0·20 hectares. Temporal correlation analysis of suspected leptospirosis cases and rainfall revealed a 2-month lag in rainfall-case association during the baseline period. Outbreak locations in 2008 were characterized by shorter distance to rivers and higher population density. The analysis suggests the possibility of household transmission in densely populated semi-urban villages as a defining characteristic of the outbreak. The role of rainfall in the outbreak remains to be investigated, although analysis here suggests a more complex relationship than simple correlation.

  5. Periodic local MP2 method employing orbital specific virtuals

    International Nuclear Information System (INIS)

    Usvyat, Denis; Schütz, Martin; Maschio, Lorenzo

    2015-01-01

    We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual space in periodic local Møller-Plesset perturbation theory of second order (LMP2). The OSVs are constructed by diagonalization of the LMP2 amplitude matrices which correspond to diagonal Wannier-function (WF) pairs. Only a subset of these OSVs is adopted for the subsequent OSV-LMP2 calculation, namely, those with largest contribution to the diagonal pair correlation energy and with the accumulated value of these contributions reaching a certain accuracy. The virtual space for a general (non diagonal) pair is spanned by the union of the two OSV sets related to the individual WFs of the pair. In the periodic LMP2 method, the diagonal LMP2 amplitude matrices needed for the construction of the OSVs are calculated in the basis of projected atomic orbitals (PAOs), employing very large PAO domains. It turns out that the OSVs are excellent to describe short range correlation, yet less appropriate for long range van der Waals correlation. In order to compensate for this bias towards short range correlation, we augment the virtual space spanned by the OSVs by the most diffuse PAOs of the corresponding minimal PAO domain. The Fock and overlap matrices in OSV basis are constructed in the reciprocal space. The 4-index electron repulsion integrals are calculated by local density fitting and, for distant pairs, via multipole approximation. New procedures for determining the fit-domains and the distant-pair lists, leading to higher efficiency in the 4-index integral evaluation, have been implemented. Generally, and in contrast to our previous PAO based periodic LMP2 method, the OSV-LMP2 method does not require anymore great care in the specification of the individual domains (to get a balanced description when calculating energy differences) and is in that sense a black box procedure. Discontinuities in potential energy surfaces, which may occur for PAO-based calculations if one is not

  6. Periodic local MP2 method employing orbital specific virtuals

    Energy Technology Data Exchange (ETDEWEB)

    Usvyat, Denis, E-mail: denis.usvyat@chemie.uni-regensburg.de; Schütz, Martin, E-mail: martin.schuetz@chemie.uni-regensburg.de [Institute for Physical and Theoretical Chemistry, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany); Maschio, Lorenzo, E-mail: lorenzo.maschio@unito.it [Dipartimento di Chimica, and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, I-10125 Torino (Italy)

    2015-09-14

    We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual space in periodic local Møller-Plesset perturbation theory of second order (LMP2). The OSVs are constructed by diagonalization of the LMP2 amplitude matrices which correspond to diagonal Wannier-function (WF) pairs. Only a subset of these OSVs is adopted for the subsequent OSV-LMP2 calculation, namely, those with largest contribution to the diagonal pair correlation energy and with the accumulated value of these contributions reaching a certain accuracy. The virtual space for a general (non diagonal) pair is spanned by the union of the two OSV sets related to the individual WFs of the pair. In the periodic LMP2 method, the diagonal LMP2 amplitude matrices needed for the construction of the OSVs are calculated in the basis of projected atomic orbitals (PAOs), employing very large PAO domains. It turns out that the OSVs are excellent to describe short range correlation, yet less appropriate for long range van der Waals correlation. In order to compensate for this bias towards short range correlation, we augment the virtual space spanned by the OSVs by the most diffuse PAOs of the corresponding minimal PAO domain. The Fock and overlap matrices in OSV basis are constructed in the reciprocal space. The 4-index electron repulsion integrals are calculated by local density fitting and, for distant pairs, via multipole approximation. New procedures for determining the fit-domains and the distant-pair lists, leading to higher efficiency in the 4-index integral evaluation, have been implemented. Generally, and in contrast to our previous PAO based periodic LMP2 method, the OSV-LMP2 method does not require anymore great care in the specification of the individual domains (to get a balanced description when calculating energy differences) and is in that sense a black box procedure. Discontinuities in potential energy surfaces, which may occur for PAO-based calculations if one is not

  7. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Diogo Ricardo da, E-mail: diogo_cost@hotmail.com [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Hansen, Matheus [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Instituto de Física, Univ. São Paulo, Rua do Matão, Cidade Universitária, 05314-970, São Paulo – SP (Brazil); Guarise, Gustavo [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Medrano-T, Rene O. [Departamento de Ciências Exatas e da Terra, UNIFESP – Universidade Federal de São Paulo, Rua São Nicolau, 210, Centro, 09913-030, Diadema, SP (Brazil); Department of Mathematics, Imperial College London, London SW7 2AZ (United Kingdom); Leonel, Edson D. [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy)

    2016-04-22

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems. - Highlights: • Extreme orbits and the organization of periodic regions in parameter space. • One-dimensional dissipative mappings. • The circle map and also a time perturbed logistic map were studied.

  8. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    International Nuclear Information System (INIS)

    Costa, Diogo Ricardo da; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

    2016-01-01

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems. - Highlights: • Extreme orbits and the organization of periodic regions in parameter space. • One-dimensional dissipative mappings. • The circle map and also a time perturbed logistic map were studied.

  9. CYCLIC VARIATIONS OF ORBITAL PERIOD AND LONG-TERM LUMINOSITY IN CLOSE BINARY RT ANDROMEDAE

    International Nuclear Information System (INIS)

    Manzoori, Davood

    2009-01-01

    Solutions of standard VR light curves for the eclipsing binary RT And were obtained using the PHOEBE program (ver. 0.3a). Absolute parameters of the stellar components were then determined, enabling them to be positioned on the mass-luminosity diagram. Times of minima data ( O - C curve ) were analyzed using the method of Kalimeris et al. A cyclic variation in the orbital period and brightness, with timescales of about 11.89 and 12.50 yr were found, respectively. This is associated with a magnetic activity cycle modulating the orbital period of RT And via the Applegate mechanism. To check the consistency of the Applegate model, we have estimated some related parameters of the RT And system. The calculated parameters were in accordance with those estimated by Applegate for other similar systems, except B, the subsurface magnetic field of which shows a rather high value for RT And.

  10. Reliability of unstable periodic orbit based control strategies in biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Nagender; Singh, Harinder P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Hasse, Maria [Institut für Höchstleistungsrechnen, Universität Stuttgart, D-70569 Stuttgart (Germany); Biswal, B. [Cluster Innovation Center, University of Delhi, Delhi 110007 (India); Sri Venkateswara College, University of Delhi, Delhi 110021 (India)

    2015-04-15

    Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.

  11. Reliability of unstable periodic orbit based control strategies in biological systems

    International Nuclear Information System (INIS)

    Mishra, Nagender; Singh, Harinder P.; Hasse, Maria; Biswal, B.

    2015-01-01

    Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics

  12. Series-nonuniform rational B-spline signal feedback: From chaos to any embedded periodic orbit or target point

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Chenxi, E-mail: cxshao@ustc.edu.cn; Xue, Yong; Fang, Fang; Bai, Fangzhou [Department of Computer Science and Technology, University of Science and Technology of China, Hefei 230027 (China); Yin, Peifeng [Department of Computer Science and Engineering, Pennsylvania State University, State College, Pennsylvania 16801 (United States); Wang, Binghong [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

    2015-07-15

    The self-controlling feedback control method requires an external periodic oscillator with special design, which is technically challenging. This paper proposes a chaos control method based on time series non-uniform rational B-splines (SNURBS for short) signal feedback. It first builds the chaos phase diagram or chaotic attractor with the sampled chaotic time series and any target orbit can then be explicitly chosen according to the actual demand. Second, we use the discrete timing sequence selected from the specific target orbit to build the corresponding external SNURBS chaos periodic signal, whose difference from the system current output is used as the feedback control signal. Finally, by properly adjusting the feedback weight, we can quickly lead the system to an expected status. We demonstrate both the effectiveness and efficiency of our method by applying it to two classic chaotic systems, i.e., the Van der Pol oscillator and the Lorenz chaotic system. Further, our experimental results show that compared with delayed feedback control, our method takes less time to obtain the target point or periodic orbit (from the starting point) and that its parameters can be fine-tuned more easily.

  13. Series-nonuniform rational B-spline signal feedback: From chaos to any embedded periodic orbit or target point.

    Science.gov (United States)

    Shao, Chenxi; Xue, Yong; Fang, Fang; Bai, Fangzhou; Yin, Peifeng; Wang, Binghong

    2015-07-01

    The self-controlling feedback control method requires an external periodic oscillator with special design, which is technically challenging. This paper proposes a chaos control method based on time series non-uniform rational B-splines (SNURBS for short) signal feedback. It first builds the chaos phase diagram or chaotic attractor with the sampled chaotic time series and any target orbit can then be explicitly chosen according to the actual demand. Second, we use the discrete timing sequence selected from the specific target orbit to build the corresponding external SNURBS chaos periodic signal, whose difference from the system current output is used as the feedback control signal. Finally, by properly adjusting the feedback weight, we can quickly lead the system to an expected status. We demonstrate both the effectiveness and efficiency of our method by applying it to two classic chaotic systems, i.e., the Van der Pol oscillator and the Lorenz chaotic system. Further, our experimental results show that compared with delayed feedback control, our method takes less time to obtain the target point or periodic orbit (from the starting point) and that its parameters can be fine-tuned more easily.

  14. Unstable Periodic Orbit Analysis of Histograms of Chaotic Time Series

    International Nuclear Information System (INIS)

    Zoldi, S.M.

    1998-01-01

    Using the Lorenz equations, we have investigated whether unstable periodic orbits (UPOs) associated with a strange attractor may predict the occurrence of the robust sharp peaks in histograms of some experimental chaotic time series. Histograms with sharp peaks occur for the Lorenz parameter value r=60.0 but not for r=28.0 , and the sharp peaks for r=60.0 do not correspond to a histogram derived from any single UPO. However, we show that histograms derived from the time series of a non-Axiom-A chaotic system can be accurately predicted by an escape-time weighting of UPO histograms. copyright 1998 The American Physical Society

  15. Modeling and analysis of periodic orbits around a contact binary asteroid

    Science.gov (United States)

    Feng, Jinglang; Noomen, Ron; Visser, Pieter N. A. M.; Yuan, Jianping

    2015-06-01

    The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is represented by a combination of an ellipsoid and a sphere. The gravitational field of this configuration is for the first time expanded into a spherical harmonics model up to degree and order 8. Compared with the exact potential, the truncation at degree and order 4 is found to introduce an error of less than 10 % at the circumscribing sphere and less than 1 % at a distance of the double of the reference radius. The Hamiltonian taking into account harmonics up to degree and order 4 is developed. After double averaging of this Hamiltonian, the model is reduced to include zonal harmonics only and frozen orbits are obtained. The tesseral terms are found to introduce significant variations on the frozen orbits and distort the frozen situation. Applying the method of Poincaré sections, phase space structures of the single-averaged model are generated for different energy levels and rotation rates of the asteroid, from which the dynamics driven by the 4×4 harmonics model is identified and POs are found. It is found that the disturbing effect of the highly irregular gravitational field on orbital motion is weakened around the polar region, and also for an asteroid with a fast rotation rate. Starting with initial conditions from this averaged model, families of exact POs in the original non-averaged system are obtained employing a numerical search method and a continuation technique. Some of these POs are stable and are candidates for future missions.

  16. INFRARED SPECTROSCOPY OF SYMBIOTIC STARS. VII. BINARY ORBIT AND LONG SECONDARY PERIOD VARIABILITY OF CH CYGNI

    International Nuclear Information System (INIS)

    Hinkle, Kenneth H.; Joyce, Richard R.; Fekel, Francis C.

    2009-01-01

    High-dispersion spectroscopic observations are used to refine orbital elements for the symbiotic binary CH Cyg. The current radial velocities, added to a previously published 13 year time series of infrared velocities for the M giant in the CH Cyg symbiotic system, more than double the length of the time series to 29 years. The two previously identified velocity periods are confirmed. The long period, revised to 15.6 ± 0.1 yr, is shown to result from a binary orbit with a 0.7 M sun white dwarf and 2 M sun M giant. Mass transfer to the white dwarf is responsible for the symbiotic classification. CH Cyg is the longest period S-type symbiotic known. Similarities with the longer period D-type systems are noted. The 2.1 year period is shown to be on Wood's sequence D, which contains stars identified as having long secondary periods (LSP). The cause of the LSP variation in CH Cyg and other stars is unknown. From our review of possible causes, we identify g-mode nonradial pulsation as the leading mechanism for LSP variation in CH Cyg. If g-mode pulsation is the cause of the LSPs, a radiative region is required near the photosphere of pulsating asymptotic giant branch stars.

  17. Improved orbits of two periodic comets: Tsuchinshan 1 and Tsuchinshan 2

    International Nuclear Information System (INIS)

    Szutowicz, S.

    1986-01-01

    The observations made during four apparitions of two comets were collected and the orbits of the comets were improved; 86 observations of Comet Tsuchinshan 1 and 50 observations of Comet Tsuchinshan 2 made in the period 1965-1985 were used. The orbit of Comet Tsuchinshan 1 was improved taking into account nongravitational effects in its motion as well as a displacement of the photometric center from the center of mass. The following values of nongravitational parameters and of observational parameter D were obtained: A 1 = 0.75953 x 10 -8 , A 2 0.00375 x 10 -8 , D = 0.34698 x 10 -3 . To link all observations of Comet Tsuchinshan 2 by one system of elements it was sufficient to add observational effects as a displacement of the photometric center from the center of mass. The following value of parameter D was obtained: D = 1.00200 x 10 -3 . The equations of motion of both comets were integrated backwards and forwards till 1992. Ephemerides for their next returns were computed. 6 refs., 5 tabs. (author)

  18. Planetary period oscillations in Saturn's magnetosphere: New results from the F-ring and proximal orbits

    Science.gov (United States)

    Provan, G.; Cowley, S. W. H.; Bunce, E. J.; Hunt, G. J.; Dougherty, M. K.

    2017-12-01

    We investigate planetary period oscillations (PPOs) in Saturn's magnetosphere using Cassini magnetic field data during the high cadence ( 7 days) F-ring and proximal orbits. Previous results have shown that there are two PPO systems, one in each hemisphere. Both PPO periods show seasonal dependence, and since mid-2014 the Northern PPO period has been 10.8 h and the Southern PPO period 10.7 h. The beat period of the two oscillations is 45 days. Previous results demonstrated that in the Northern (Southern) polar region only pure Northern (Southern) oscillations can be observed, whilst in the equatorial region both oscillations are present and constructively and destructively interfere over the beat-cycle of the two oscillations. The PPOs are believed to be driven by twin-cell convection patterns in the polar ionosphere/thermosphere regions, with two systems of field-aligned currents transmitting the PPO flows to the magnetospheric plasma.The F-ring and proximal orbits uniquely observe the PPOs over 6 orbits during each PPO beat cycle. This high-cadence data demonstrates that over a beat cycle both the periods and amplitudes of the PPO observed within the each polar region are modulated by the PPO system from the opposite hemisphere. When the two oscillations are in phase (anti-phase) the `drag' of one system on the other acts to decrease (increase) the amplitude of the oscillations and the two PPO periods diverge (converge). We present a theoretical model showing that this coupling is due to the PPO flows from one hemisphere not just being communicated to the magnetosphere as previously assumed, but also to the opposite hemisphere. The result is inter-hemispheric coupling of the PPO flow systems within the ionosphere/thermosphere system, so that the northern PPO system drives a northern twin-cell convection pattern in the southern hemisphere, and vice versa, thus leading to the observed polar modulations of the PPOs.We will also present PPO phase models determined

  19. Do slow orbital periodicities appear in the record of earth's magnetic reversals?

    Science.gov (United States)

    Stothers, Richard B.

    1987-01-01

    Time-series spectral analysis has been performed on the dates of geomagnetic reversals of the last 20 Myr BP and earlier. Possible evidence is found from the presence of high spectral peaks for two very long periodicities, 0.4 Myr and 1.3 Myr, that may be associated with slow variations of the earth's orbital eccentricity as predicted by Berger. However, statistical significance tests and a number of other arguments do not confirm the two detections.

  20. A review of orbital and intracranial magnetic resonance imaging in 79 canine and 13 feline patients (2004-2010).

    Science.gov (United States)

    Armour, Micki D; Broome, Michael; Dell'Anna, Giuseppe; Blades, Natalie J; Esson, Douglas W

    2011-07-01

    To review the distribution of orbital and intracranial disease in canine and feline patients undergoing magnetic resonance imaging (MRI) following referral to a veterinary ophthalmologist and to correlate results of MRI with pathologic conditions including neoplasia, suspected optic neuritis (ON) and orbital cellulitis. Recognized and emerging imaging techniques are reviewed. Medical records of 79 canine and 13 feline patients were reviewed. Neoplasia was diagnosed in 53/92 (57.6%) of patients. The most prevalent types of neoplasia were carcinoma (16/53, 30.1%), sarcoma (11/53, 20.8%), lymphoma (8/53, 15.1%) and presumptive meningioma (9/53, 17.0%). Carcinomas and sarcomas were characterized by bony lysis and intracranial/sinonasal extension. Lymphoma was generally unilateral, less invasive and originated from the ventromedial orbit. Intracranial masses representing presumptive meningiomas frequently exhibited a 'dural tail' sign. Diagnosis of suspected ON was made in 13 of 92 (14.1%) patients. Results of MRI in patients with suspected ON included unilateral optic nerve hyperintensity (3/13, 23.0%), bilateral optic nerve hyperintensity (1/13, 7.7%) and optic chiasmal hyperintensity (3/13, 23.0%). Seven suspected ON patients demonstrated intracranial multifocal patchy contrast enhancement (7/13, 53.8%). Diagnosis of orbital cellulitis was made in 12/92 (13.0%) patients. Orbital neoplasia was the most common pathologic condition detected. Essential Roentgen characteristics are helpful when diagnosing pathologic processes and providing prognoses in cases of orbital or intracranial disease. Magnetic resonance imaging comprises an important diagnostic component in cases of suspected ON. Emerging contrast and functional MRI techniques as well as SI data may increase our ability to characterize disease processes. © 2011 American College of Veterinary Ophthalmologists.

  1. Quantum mechanical analysis of fractal conductance fluctuations: a picture using self-similar periodic orbits

    International Nuclear Information System (INIS)

    Ogura, Tatsuo; Miyamoto, Masanori; Budiyono, Agung; Nakamura, Katsuhiro

    2007-01-01

    Fractal magnetoconductance fluctuations are often observed in experiments on ballistic quantum dots. Although the analysis of the exact self-affine fractal has been given by the semiclassical theory using self-similar periodic orbits in systems with a soft-walled potential with a saddle, there has been no corresponding quantum mechanical investigation. We numerically calculate the quantum conductance with use of the recursive Green's function method applied to open cavities characterized by a Henon-Heiles type potential. The conductance fluctuations show exact self-affinity just as in some of the experimental observations. The enlargement factor for the horizontal axis can be explained by the scaling factor of the area of self-similar periodic orbits, and therefore be attributed to the curvature of the saddle in the cavity potential. The fractal dimension obtained through the box counting method agrees with those evaluated with use of the Hurst exponent, and coincides with the semiclassical prediction. We further investigate the variation of the fractal dimension by changing the control parameters between the classical and quantum domains. (fast track communication)

  2. Building CX peanut-shaped disk galaxy profiles. The relative importance of the 3D families of periodic orbits bifurcating at the vertical 2:1 resonance

    Science.gov (United States)

    Patsis, P. A.; Harsoula, M.

    2018-05-01

    Context. We present and discuss the orbital content of a rather unusual rotating barred galaxy model, in which the three-dimensional (3D) family, bifurcating from x1 at the 2:1 vertical resonance with the known "frown-smile" side-on morphology, is unstable. Aims: Our goal is to study the differences that occur in the phase space structure at the vertical 2:1 resonance region in this case, with respect to the known, well studied, standard case, in which the families with the frown-smile profiles are stable and support an X-shaped morphology. Methods: The potential used in the study originates in a frozen snapshot of an N-body simulation in which a fast bar has evolved. We follow the evolution of the vertical stability of the central family of periodic orbits as a function of the energy (Jacobi constant) and we investigate the phase space content by means of spaces of section. Results: The two bifurcating families at the vertical 2:1 resonance region of the new model change their stability with respect to that of most studied analytic potentials. The structure in the side-on view that is directly supported by the trapping of quasi-periodic orbits around 3D stable periodic orbits has now an infinity symbol (i.e. ∞-type) profile. However, the available sticky orbits can reinforce other types of side-on morphologies as well. Conclusions: In the new model, the dynamical mechanism of trapping quasi-periodic orbits around the 3D stable periodic orbits that build the peanut, supports the ∞-type profile. The same mechanism in the standard case supports the X shape with the frown-smile orbits. Nevertheless, in both cases (i.e. in the new and in the standard model) a combination of 3D quasi-periodic orbits around the stable x1 family with sticky orbits can support a profile reminiscent of the shape of the orbits of the 3D unstable family existing in each model.

  3. Synchronizing movements with the metronome: nonlinear error correction and unstable periodic orbits.

    Science.gov (United States)

    Engbert, Ralf; Krampe, Ralf Th; Kurths, Jürgen; Kliegl, Reinhold

    2002-02-01

    The control of human hand movements is investigated in a simple synchronization task. We propose and analyze a stochastic model based on nonlinear error correction; a mechanism which implies the existence of unstable periodic orbits. This prediction is tested in an experiment with human subjects. We find that our experimental data are in good agreement with numerical simulations of our theoretical model. These results suggest that feedback control of the human motor systems shows nonlinear behavior. Copyright 2001 Elsevier Science (USA).

  4. Analytical and numerical construction of vertical periodic orbits about triangular libration points based on polynomial expansion relations among directions

    Science.gov (United States)

    Qian, Ying-Jing; Yang, Xiao-Dong; Zhai, Guan-Qiao; Zhang, Wei

    2017-08-01

    Innovated by the nonlinear modes concept in the vibrational dynamics, the vertical periodic orbits around the triangular libration points are revisited for the Circular Restricted Three-body Problem. The ζ -component motion is treated as the dominant motion and the ξ and η -component motions are treated as the slave motions. The slave motions are in nature related to the dominant motion through the approximate nonlinear polynomial expansions with respect to the ζ -position and ζ -velocity during the one of the periodic orbital motions. By employing the relations among the three directions, the three-dimensional system can be transferred into one-dimensional problem. Then the approximate three-dimensional vertical periodic solution can be analytically obtained by solving the dominant motion only on ζ -direction. To demonstrate the effectiveness of the proposed method, an accuracy study was carried out to validate the polynomial expansion (PE) method. As one of the applications, the invariant nonlinear relations in polynomial expansion form are used as constraints to obtain numerical solutions by differential correction. The nonlinear relations among the directions provide an alternative point of view to explore the overall dynamics of periodic orbits around libration points with general rules.

  5. To the problem of DQ Herculis orbital period variations.

    Science.gov (United States)

    Dmitrienko, E. S.

    The eclipses of the primary component by the secondary one in DQ Her (Nova Her 1934) were analyzed using the light curves obtained by photometrical observations in 1982 - 1986. It is suspected that the value O-C is varying with time according to a sinusoidal law with the period of about 5 years and the amplitude ≡3 - 4 min. The secondary minimum is not shown up on the UBVRI-light curves of DQ Her. That is why the two hypotheses - the apsidal motion and the third component in the system - would seem adequate to explain the sinusoidal change of the value "O-C". By assuming that a probable sinusoidal dependence O-C on time occurs due to apsidal motion, it can be a result of deformation of the secondary component shape, since the contribution from the relativistic motion does not exceed 5%. The obtained value of k2 for the models with zero viscosity is (1 - 5)×10-3 that corresponds to a very high concentration of stellar matter toward the centre of the star. Application of models with the viscosity not equal to zero must lead to the increase of the k2 parameter.

  6. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. II. UPDATED BINARY STAR ORBITS AND A LONG PERIOD ECLIPSING BINARY

    International Nuclear Information System (INIS)

    Muterspaugh, Matthew W.; O'Connell, J.; Hartkopf, William I.; Lane, Benjamin F.; Williamson, M.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M.; Wiktorowicz, Sloane J.

    2010-01-01

    Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture measurements covering a much longer timespan (from eyepiece measurements, speckle interferometry, and adaptive optics) to determine improved visual orbits for 20 binary stars. In some cases, radial velocity observations exist to constrain the full three-dimensional orbit and determine component masses. The visual orbit of one of these binaries-α Com (HD 114378)-shows that the system is likely to have eclipses, despite its very long period of 26 years. The next eclipse is predicted to be within a week of 2015 January 24.

  7. Approaching the theoretical limit in periodic local MP2 calculations with atomic-orbital basis sets: the case of LiH.

    Science.gov (United States)

    Usvyat, Denis; Civalleri, Bartolomeo; Maschio, Lorenzo; Dovesi, Roberto; Pisani, Cesare; Schütz, Martin

    2011-06-07

    The atomic orbital basis set limit is approached in periodic correlated calculations for solid LiH. The valence correlation energy is evaluated at the level of the local periodic second order Møller-Plesset perturbation theory (MP2), using basis sets of progressively increasing size, and also employing "bond"-centered basis functions in addition to the standard atom-centered ones. Extended basis sets, which contain linear dependencies, are processed only at the MP2 stage via a dual basis set scheme. The local approximation (domain) error has been consistently eliminated by expanding the orbital excitation domains. As a final result, it is demonstrated that the complete basis set limit can be reached for both HF and local MP2 periodic calculations, and a general scheme is outlined for the definition of high-quality atomic-orbital basis sets for solids. © 2011 American Institute of Physics

  8. Numerical continuation of families of heteroclinic connections between periodic orbits in a Hamiltonian system

    Science.gov (United States)

    Barrabés, E.; Mondelo, J. M.; Ollé, M.

    2013-10-01

    This paper is devoted to the numerical computation and continuation of families of heteroclinic connections between hyperbolic periodic orbits (POs) of a Hamiltonian system. We describe a method that requires the numerical continuation of a nonlinear system that involves the initial conditions of the two POs, the linear approximations of the corresponding manifolds and a point in a given Poincaré section where the unstable and stable manifolds match. The method is applied to compute families of heteroclinic orbits between planar Lyapunov POs around the collinear equilibrium points of the restricted three-body problem in different scenarios. In one of them, for the Sun-Jupiter mass parameter, we provide energy ranges for which the transition between different resonances is possible.

  9. The first photometric investigation and orbital period variation analysis of the W UMa type binary IK Bootis

    Science.gov (United States)

    Kriwattanawong, Wichean; Sanguansak, Nuanwan; Maungkorn, Sakdawoot

    2017-08-01

    With new CCD observations of the W UMa type binary IK Boo, we present the first investigation of photometric parameters and orbital period change. The BVRc light curve fit shows that IK Boo is a W-type contact system with a mass ratio of q = 1.146 and a shallow contact with a fill-out factor of f = 2.22%. The orbital period decrease was found to be a rate of -3.28 × 10-7 d yr-1, corresponding to a mass transfer from the more massive to the less massive component with a rate of -2.83 × 10-6 M⊙ yr-1. The inner and outer critical Roche lobes will contract and cause the contact degree to increase. Therefore, IK Boo may evolve into a deeper contact system. Furthermore, a possible cyclic variation was found with a period of 9.74 yr, which could be explained by the light-travel time effect due to the existence of a third companion in the system.

  10. Orbital period variations of two W UMa-type binaries: UY UMa and EF Boo

    Science.gov (United States)

    Yu, Yun-Xia; Zhang, Xu-Dong; Hu, Ke; Xiang, Fu-Yuan

    2017-08-01

    The orbital period variations of two W UMa-type contact binaries, UY UMa and EF Boo, are analyzed by using all available times of light minimum. It is detected that the general trends of their (O - C) curves show an upward parabolic variation, which reveals their continuous period increases at the rates of dP / dt = 2.545 ×10-7 days yr-1 and dP / dt = 2.623 ×10-7 days yr-1 , respectively. Meanwhile, UY UMa also shows a cyclic period variation with a small amplitude of A = 0.0026 days superposed on the long-term increase. Due to their contact configurations, the secular period increases are interpreted as a result of mass transfer from the less massive component to the more massive one. The cyclic period variation of UY UMa may be interpreted in terms of either the magnetic activity or the light time effect.

  11. Reconstruction of chaotic saddles by classification of unstable periodic orbits: Kuramoto-Sivashinsky equation

    Energy Technology Data Exchange (ETDEWEB)

    Saiki, Yoshitaka, E-mail: yoshi.saiki@r.hit-u.ac.jp [Graduate School of Commerce and Management, Hitotsubashi University, Tokyo 186-8601 (Japan); Yamada, Michio [Research Institute for Mathematical Sciences (RIMS), Kyoto University, Kyoto 606-8502 (Japan); Chian, Abraham C.-L. [Paris Observatory, LESIA, CNRS, 92195 Meudon (France); National Institute for Space Research (INPE), P.O. Box 515, São José dos Campos, São Paulo 12227-010 (Brazil); Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), São José dos Campos, São Paulo 12228-900 (Brazil); School of Mathematical Sciences, University of Adelaide, Adelaide SA 5005 (Australia); Department of Biomedical Engineering, George Washington University, Washington, DC 20052 (United States); Miranda, Rodrigo A. [Faculty UnB-Gama, and Plasma Physics Laboratory, Institute of Physics, University of Brasília (UnB), Brasília DF 70910-900 (Brazil); Rempel, Erico L. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), São José dos Campos, São Paulo 12228-900 (Brazil)

    2015-10-15

    The unstable periodic orbits (UPOs) embedded in a chaotic attractor after an attractor merging crisis (MC) are classified into three subsets, and employed to reconstruct chaotic saddles in the Kuramoto-Sivashinsky equation. It is shown that in the post-MC regime, the two chaotic saddles evolved from the two coexisting chaotic attractors before crisis can be reconstructed from the UPOs embedded in the pre-MC chaotic attractors. The reconstruction also involves the detection of the mediating UPO responsible for the crisis, and the UPOs created after crisis that fill the gap regions of the chaotic saddles. We show that the gap UPOs originate from saddle-node, period-doubling, and pitchfork bifurcations inside the periodic windows in the post-MC chaotic region of the bifurcation diagram. The chaotic attractor in the post-MC regime is found to be the closure of gap UPOs.

  12. Reconstruction of chaotic saddles by classification of unstable periodic orbits: Kuramoto-Sivashinsky equation

    International Nuclear Information System (INIS)

    Saiki, Yoshitaka; Yamada, Michio; Chian, Abraham C.-L.; Miranda, Rodrigo A.; Rempel, Erico L.

    2015-01-01

    The unstable periodic orbits (UPOs) embedded in a chaotic attractor after an attractor merging crisis (MC) are classified into three subsets, and employed to reconstruct chaotic saddles in the Kuramoto-Sivashinsky equation. It is shown that in the post-MC regime, the two chaotic saddles evolved from the two coexisting chaotic attractors before crisis can be reconstructed from the UPOs embedded in the pre-MC chaotic attractors. The reconstruction also involves the detection of the mediating UPO responsible for the crisis, and the UPOs created after crisis that fill the gap regions of the chaotic saddles. We show that the gap UPOs originate from saddle-node, period-doubling, and pitchfork bifurcations inside the periodic windows in the post-MC chaotic region of the bifurcation diagram. The chaotic attractor in the post-MC regime is found to be the closure of gap UPOs

  13. Numerical determination of families of three-dimensional double-symmetric periodic orbits in the restricted three-body problem. Pt. 1

    International Nuclear Information System (INIS)

    Kazantzis, P.G.

    1979-01-01

    New families of three-dimensional double-symmetric periodic orbits are determined numerically in the Sun-Jupiter case of the restricted three-body problem. These families bifurcate from the 'vertical-critical' orbits (αsub(ν) = -1, csub(ν) = 0) of the 'basic' plane families i. g 1 g 2 h, a, m and I. Further the numerical procedure employed in the determination of these families has been described and interesting results have been pointed out. Also, computer plots of the orbits of these families have been shown in conical projections. (orig.)

  14. The shortage of long-period comets in elliptical orbits

    International Nuclear Information System (INIS)

    Everhart, E.

    1979-01-01

    Based on the number of 'new' comets seen on near-parabolic orbits, one can predict the number of comets that should be found on definitely elliptical orbits on their subsequent returns. The author shows that about three out of four of these returning comets are not observed. (Auth.)

  15. Numerical detection of unstable periodic orbits in continuous-time dynamical systems with chaotic behaviors

    Directory of Open Access Journals (Sweden)

    Y. Saiki

    2007-09-01

    Full Text Available An infinite number of unstable periodic orbits (UPOs are embedded in a chaotic system which models some complex phenomenon. Several algorithms which extract UPOs numerically from continuous-time chaotic systems have been proposed. In this article the damped Newton-Raphson-Mees algorithm is reviewed, and some important techniques and remarks concerning the practical numerical computations are exemplified by employing the Lorenz system.

  16. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    Science.gov (United States)

    da Costa, Diogo Ricardo; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

    2016-04-01

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems.

  17. Equilibrium points and associated periodic orbits in the gravity of binary asteroid systems: (66391) 1999 KW4 as an example

    Science.gov (United States)

    Shi, Yu; Wang, Yue; Xu, Shijie

    2018-04-01

    The motion of a massless particle in the gravity of a binary asteroid system, referred as the restricted full three-body problem (RF3BP), is fundamental, not only for the evolution of the binary system, but also for the design of relevant space missions. In this paper, equilibrium points and associated periodic orbit families in the gravity of a binary system are investigated, with the binary (66391) 1999 KW4 as an example. The polyhedron shape model is used to describe irregular shapes and corresponding gravity fields of the primary and secondary of (66391) 1999 KW4, which is more accurate than the ellipsoid shape model in previous studies and provides a high-fidelity representation of the gravitational environment. Both of the synchronous and non-synchronous states of the binary system are considered. For the synchronous binary system, the equilibrium points and their stability are determined, and periodic orbit families emanating from each equilibrium point are generated by using the shooting (multiple shooting) method and the homotopy method, where the homotopy function connects the circular restricted three-body problem and RF3BP. In the non-synchronous binary system, trajectories of equivalent equilibrium points are calculated, and the associated periodic orbits are obtained by using the homotopy method, where the homotopy function connects the synchronous and non-synchronous systems. Although only the binary (66391) 1999 KW4 is considered, our methods will also be well applicable to other binary systems with polyhedron shape data. Our results on equilibrium points and associated periodic orbits provide general insights into the dynamical environment and orbital behaviors in proximity of small binary asteroids and enable the trajectory design and mission operations in future binary system explorations.

  18. Interrater reliability of sonographic examinations of orbital fractures

    International Nuclear Information System (INIS)

    Siegfried, Jank; Martina, Deibl; Heinrich, Strobl; Andreas, Oberrauch; Alessandro, Nicasi; Martin, Missmann; Gerd, Bodner

    2005-01-01

    Objective: The purpose of this study is to determine whether there are statistically significant variations among different observers when examining fractures of the orbital walls. Material and methods: From December 2003 to April 2004, 28 patients with clinically suspected orbital fractures were examined by ultrasound prospectively. The US images of the infra-orbital margins, the orbital floors, the medial and lateral orbital walls of each patient were reexamined by two independent investigators. Results: Computed tomography revealed fractures of the orbital floor in 28 out of 31 patients (90.3%). The infra-orbital margins showed fractures of 14 of 31 patients (45.2%). The ultrasound examinations of the orbits by the three examiners presented satisfactory correlation regarding sensitivity and specificity. There were no significant differences between investigators. There was good agreement among the ultrasound examiners regarding the infra-orbital margins. This was not the case for the orbital floors. Conclusions: If there are clear cut clinical findings ultrasound examination could represent an alternative to computed tomography. If the clinical findings were indeterminate, computed tomography was essential as implicated by this study. Accordingly, further evaluation of ultrasound examinations of fractures of the orbital margins and floors are necessary

  19. Orbits in weak and strong bars

    CERN Document Server

    Contopoulos, George

    1980-01-01

    The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).

  20. On the Post-Keplerian Corrections to the Orbital Periods of a Two-body System and Their Application to the Galactic Center

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, Lorenzo [Ministero dell’Istruzione, dell’Università e della Ricerca (M.I.U.R.)-Istruzione (Italy); Zhang, Fupeng, E-mail: lorenzo.iorio@libero.it, E-mail: zhangfp7@mail.sysu.edu.cn [School of Physics and Astronomy, Sun Yat-Sen University, Guangzhou 510275 (China)

    2017-04-10

    We perform detailed numerical analyses of the orbital motion of a test particle around a spinning primary, with the aim of investigating the possibility of using the post-Keplerian (pK) corrections to the orbiter’s periods (draconitic, anomalistic, and sidereal) as a further opportunity to perform new tests of post-Newtonian gravity. As a specific scenario, the S-stars orbiting the massive black hole (MBH) supposedly lurking in Sgr A* at the center of the Galaxy are adopted. We first study the effects of the pK Schwarzchild, Lense–Thirring, and quadrupole moment accelerations experienced by a target star for various possible initial orbital configurations. It turns out that the results of the numerical simulations are consistent with the analytical ones in the small eccentricity approximation for which almost all the latter ones were derived. For highly elliptical orbits, the sizes of the three pK corrections considered turn out to increase remarkably. The periods of the observed S2 and S0-102 stars as functions of the MBH’s spin axis orientation are considered as well. The pK accelerations lead to corrections of the orbital periods of the order of 1–100 days (Schwarzschild), 0.1–10 hr (Lense–Thirring), and 1–10{sup 3} s (quadrupole) for a target star with a = 300–800 au and e ≈ 0.8, which could be measurable with future facilities.

  1. Absence of periodic orbits in digital memcomputing machines with solutions

    Science.gov (United States)

    Di Ventra, Massimiliano; Traversa, Fabio L.

    2017-10-01

    In Traversa and Di Ventra [Chaos 27, 023107 (2017)] we argued, without proof, that if the non-linear dynamical systems with memory describing the class of digital memcomputing machines (DMMs) have equilibrium points, then no periodic orbits can emerge. In fact, the proof of such a statement is a simple corollary of a theorem already demonstrated in Traversa and Di Ventra [Chaos 27, 023107 (2017)]. Here, we point out how to derive such a conclusion. Incidentally, the same demonstration implies absence of chaos, a result we have already demonstrated in Di Ventra and Traversa [Phys. Lett. A 381, 3255 (2017)] using topology. These results, together with those in Traversa and Di Ventra [Chaos 27, 023107 (2017)], guarantee that if the Boolean problem the DMMs are designed to solve has a solution, the system will always find it, irrespective of the initial conditions.

  2. Possible Periodic Orbit Control Maneuvers for an eLISA Mission

    Science.gov (United States)

    Bender, Peter L.; Welter, Gary L.

    2012-01-01

    This paper investigates the possible application of periodic orbit control maneuvers for so-called evolved-LISA (eLISA) missions, i.e., missions for which the constellation arm lengths and mean distance from the Earth are substantially reduced. We find that for missions with arm lengths of 106 km and Earth-trailing distance ranging from approx. 12deg to 20deg over the science lifetime, the occasional use of the spacecraft micro-Newton thrusters for constellation configuration maintenance should be able to essentially eliminate constellation distortion caused by Earth-induced tidal forces at a cost to science time of only a few percent. With interior angle variation kept to approx. +/-0:1deg, the required changes in the angles between the laser beam pointing directions for the two arms from any spacecraft could be kept quite small. This would considerably simplify the apparatus necessary for changing the transmitted beam directions.

  3. Tandem Swift and INTEGRAL Data to Revisit the Orbital and Superorbital Periods of 1E 1740.7–2942

    Energy Technology Data Exchange (ETDEWEB)

    Stecchini, Paulo Eduardo; Castro, Manuel; Jablonski, Francisco; D’Amico, Flavio; Braga, João [Instituto Nacional de Pesquisas Espaciais—INPE, Av. dos Astronautas 1758, 12227-010, S.J.Campos-SP (Brazil)

    2017-07-01

    The black hole candidate 1E 1740.7−2942 is one of the strongest hard X-ray sources in the Galactic Center region. No counterparts in longer wavelengths have been identified for this object yet. The presence of characteristic timing signatures in the flux history of X-ray sources has been shown to be an important diagnostic tool for the properties of these systems. Using simultaneous data from NASA’s Swift and ESA’s INTEGRAL missions, we have found two periodic signatures at 12.61 ± 0.06 days and 171.1 ± 3.0 days in long-term hard X-ray light curves of 1E 1740.7−2942. We interpret those as the orbital and superorbital periods of the object, respectively. The reported orbital period is in good agreement with previous studies of 1E 1740.7−2942 using NASA’s RXTE data. We present here the first firm evidence of a superorbital period for 1E 1740.7−2942, which has important implications for the nature of the binary system.

  4. Case of acute orbital myositis which was difficult to diagnose at first

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Kiyoshi; Terabayashi, Tadasu; Mori, Hiroshi; Niida, Hirohito; Sugiyama, Yoshiaki; Nakagawa, Masato

    1988-02-01

    We report a case of acute orbital myositis. A 61-year-old woman exhibited acute orbital pain, diplopia, and left proptosis. Examination revealed a 5-mm left proptosis, left chemosis, and limitations in all directions of the movement of the left eye. Visual acuity was unimpaired, however, and the neurological examination was otherwise normal. CT demonstrated a left inferior orbital mass. We suspected an acute orbital pseudotumor based on the rapid onset and the clinical symptoms. We treated her with systemic corticosteroids. Four weeks later CT documented a reduced left orbital mass; there seemed to be left only an inferior rectus muscle enlargement. We diagnosed acute orbital myositis, a subgroup of orbital pseudotumors, based upon the rapid clinical presentation, the CT features, and the resolution after treatment with systemic corticosteroids.

  5. SWIFT-BAT HARD X-RAY SKY MONITORING UNVEILS THE ORBITAL PERIOD OF THE HMXB IGR J18219–1347

    International Nuclear Information System (INIS)

    La Parola, V.; Cusumano, G.; Segreto, A.; D'Aì, A.; Masetti, N.; D'Elia, V.

    2013-01-01

    IGR J18219–1347 is a hard X-ray source discovered by INTEGRAL in 2010. We have analyzed the X-ray emission of this source exploiting the Burst Alert Telescope (BAT) survey data up to 2012 March and the X-Ray Telescope (XRT) data that include also an observing campaign performed in early 2012. The source is detected at a significance level of ∼13 standard deviations in the 88 month BAT survey data, and shows a strong variability along the survey monitoring, going from high intensity to quiescent states. A timing analysis on the BAT data revealed an intensity modulation with a period of P 0 = 72.44 ± 0.3 days. The significance of this modulation is about seven standard deviations in Gaussian statistics. We interpret it as the orbital period of the binary system. The light curve folded at P 0 shows a sharp peak covering ∼30% of the period, superimposed to a flat level roughly consistent with zero. In the soft X-rays the source is detected only in 5 out of 12 XRT observations, with the highest recorded count rate corresponding to a phase close to the BAT folded light-curve peak. The long orbital period and the evidence that the source emits only during a small fraction of the orbit suggests that the IGR J18219–1347 binary system hosts a Be star. The broadband XRT+BAT spectrum is well modeled with a flat absorbed power law with a high-energy exponential cutoff at ∼11 keV

  6. Relativistic Spin-Orbit Heavy Atom on the Light Atom NMR Chemical Shifts: General Trends Across the Periodic Table Explained.

    Science.gov (United States)

    Vícha, Jan; Komorovsky, Stanislav; Repisky, Michal; Marek, Radek; Straka, Michal

    2018-05-10

    The importance of relativistic effects on the NMR parameters in heavy-atom (HA) compounds, particularly the SO-HALA (Spin-Orbit Heavy Atom on the Light Atom) effect on NMR chemical shifts, has been known for about 40 years. Yet, a general correlation between the electronic structure and SO-HALA effect has been missing. By analyzing 1 H NMR chemical shifts of the sixth-period hydrides (Cs-At), we discovered general electronic-structure principles and mechanisms that dictate the size and sign of the SO-HALA NMR chemical shifts. In brief, partially occupied HA valence shells induce relativistic shielding at the light atom (LA) nuclei, while empty HA valence shells induce relativistic deshielding. In particular, the LA nucleus is relativistically shielded in 5d 2 -5d 8 and 6p 4 HA hydrides and deshielded in 4f 0 , 5d 0 , 6s 0 , and 6p 0 HA hydrides. This general and intuitive concept explains periodic trends in the 1 H NMR chemical shifts along the sixth-period hydrides (Cs-At) studied in this work. We present substantial evidence that the introduced principles have a general validity across the periodic table and can be extended to nonhydride LAs. The decades-old question of why compounds with occupied frontier π molecular orbitals (MOs) cause SO-HALA shielding at the LA nuclei, while the frontier σ MOs cause deshielding is answered. We further derive connection between the SO-HALA NMR chemical shifts and Spin-Orbit-induced Electron Deformation Density (SO-EDD), a property that can be obtained easily from differential electron densities and can be represented graphically. SO-EDD provides an intuitive understanding of the SO-HALA effect in terms of the depletion/concentration of the electron density at LA nuclei caused by spin-orbit coupling due to HA in the presence of a magnetic field. Using an analogy between the SO-EDD concept and arguments from classic NMR theory, the complex question of the SO-HALA NMR chemical shifts becomes easily understandable for a wide

  7. Periodic orbits and 10 cases of unbounded dynamics for one Hamiltonian system defined by the conformally coupled field

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, Konstantin E., E-mail: kstarkov@ipn.mx

    2015-07-03

    In this paper we study invariant domains with unbounded dynamics for one cosmological Hamiltonian system which is formed by the conformally coupled field; this system was introduced by Maciejewski et al. (2007). We find a few groups of conditions imposed on parameters of this system for which all trajectories are unbounded in both of time directions. Further, we present a few groups of other conditions imposed on system parameters under which we localize the invariant domain with unbounded dynamics; this domain is defined with help of bounds for values of the Hamiltonian level surface parameter. We describe one group of conditions when our system possesses two periodic orbits found explicitly. In some of rest cases we get localization bounds for compact invariant sets. - Highlights: • Equations for periodic orbits are got for many level sets. • Domains with unbounded dynamics are localized. • Localizations for compact invariant sets are obtained.

  8. Chebyshev-Taylor Parameterization of Stable/Unstable Manifolds for Periodic Orbits: Implementation and Applications

    Science.gov (United States)

    Mireles James, J. D.; Murray, Maxime

    2017-12-01

    This paper develops a Chebyshev-Taylor spectral method for studying stable/unstable manifolds attached to periodic solutions of differential equations. The work exploits the parameterization method — a general functional analytic framework for studying invariant manifolds. Useful features of the parameterization method include the fact that it can follow folds in the embedding, recovers the dynamics on the manifold through a simple conjugacy, and admits a natural notion of a posteriori error analysis. Our approach begins by deriving a recursive system of linear differential equations describing the Taylor coefficients of the invariant manifold. We represent periodic solutions of these equations as solutions of coupled systems of boundary value problems. We discuss the implementation and performance of the method for the Lorenz system, and for the planar circular restricted three- and four-body problems. We also illustrate the use of the method as a tool for computing cycle-to-cycle connecting orbits.

  9. High Velocity Spectroscopic Binary Orbits from Photoelectric Radial Velocities: BD+20 5152, a Possible Triple System

    Directory of Open Access Journals (Sweden)

    Sperauskas J.

    2010-12-01

    Full Text Available The spectroscopic orbit of a high proper motion star, BD+20 5152, is calculated from 34 CORAVEL-type radial velocity measurements. The star has a slightly eccentric orbit with a period of 5.70613 d, half-amplitude of 47.7 km/s and eccentricity of 0.049. The center-of-mass velocity of the system is -24.3 km/s. BD+20 5152 seems to be a triple system consisting of a G8 dwarf as a primary component and of two K6-M0 dwarfs as secondary and tertiary components. This model is based on the analysis of its UBVRI and JHK magnitudes. According to the SuperWASP photometry, spots on the surface of the primary are suspected. The excessive brightness in the Galex FUV and NUV magnitudes and a non-zero eccentricity suggest the age of this system to be less than 1 Gyr.

  10. A case of acute orbital myositis which was difficult to diagnose at first

    International Nuclear Information System (INIS)

    Yamamoto, Kiyoshi; Terabayashi, Tadasu; Mori, Hiroshi; Niida, Hirohito; Sugiyama, Yoshiaki; Nakagawa, Masato

    1988-01-01

    We report a case of acute orbital myositis. A 61-year-old woman exhibited acute orbital pain, diplopia, and left proptosis. Examination revealed a 5-mm left proptosis, left chemosis, and limitations in all directions of the movement of the left eye. Visual acuity was unimpaired, however, and the neurological examination was otherwise normal. CT demonstrated a left inferior orbital mass. We suspected an acute orbital pseudotumor based on the rapid onset and the clinical symptoms. We treated her with systemic corticosteroids. Four weeks later CT documented a reduced left orbital mass; there seemed to be left only an inferior rectus muscle enlargement. We diagnosed acute orbital myositis, a subgroup of orbital pseudotumors, based upon the rapid clinical presentation, the CT features, and the resolution after treatment with systemic corticosteroids. (author)

  11. Enumeration and stability analysis of simple periodic orbits in β-Fermi Pasta Ulam lattice

    International Nuclear Information System (INIS)

    Sonone, Rupali L.; Jain, Sudhir R.

    2014-01-01

    We study the well-known one-dimensional problem of N particles with a nonlinear interaction. The special case of quadratic and quartic interaction potential among nearest neighbours is the β-Fermi-Pasta-Ulam model. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. Such stability analysis is crucial to understand the transition of FPU lattice from recurrences to globally chaotic behavior, energy transport in lower dimensional system, dynamics of optical lattices and also its impact on shape parameter of bio-polymers such as DNA and RNA

  12. Enumeration and stability analysis of simple periodic orbits in β-Fermi Pasta Ulam lattice

    Energy Technology Data Exchange (ETDEWEB)

    Sonone, Rupali L., E-mail: vaidehisonone@gmail.com; Jain, Sudhir R., E-mail: vaidehisonone@gmail.com [Department of Physics, University of Pune, Pune-411007, India and Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

    2014-04-24

    We study the well-known one-dimensional problem of N particles with a nonlinear interaction. The special case of quadratic and quartic interaction potential among nearest neighbours is the β-Fermi-Pasta-Ulam model. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. Such stability analysis is crucial to understand the transition of FPU lattice from recurrences to globally chaotic behavior, energy transport in lower dimensional system, dynamics of optical lattices and also its impact on shape parameter of bio-polymers such as DNA and RNA.

  13. Space station orbit maintenance

    Science.gov (United States)

    Kaplan, D. I.; Jones, R. M.

    1983-01-01

    The orbit maintenance problem is examined for two low-earth-orbiting space station concepts - the large, manned Space Operations Center (SOC) and the smaller, unmanned Science and Applications Space Platform (SASP). Atmospheric drag forces are calculated, and circular orbit altitudes are selected to assure a 90 day decay period in the event of catastrophic propulsion system failure. Several thrusting strategies for orbit maintenance are discussed. Various chemical and electric propulsion systems for orbit maintenance are compared on the basis of propellant resupply requirements, power requirements, Shuttle launch costs, and technology readiness.

  14. On the periodic orbits of the Third-order differential equation x ' ' '- x ' ' x'- x= F(x,x',x ' ')

    OpenAIRE

    Llibre, Jaume

    2013-01-01

    Agraïments: The second author is partially supported by CAPES/MECD-DGU 222/2010 Brazil and Spain In this paper we study the periodic orbits of the third-order differential equation x''' − µx'' + x' − µx = εF(x, x', x''), where ε is a small parameter and the function F is of class C2.

  15. Man-Made Debris In and From Lunar Orbit

    Science.gov (United States)

    Johnson, Nicholas L.; McKay, Gordon A. (Technical Monitor)

    1999-01-01

    During 1966-1976, as part of the first phase of lunar exploration, 29 manned and robotic missions placed more than 40 objects into lunar orbit. Whereas several vehicles later successfully landed on the Moon and/or returned to Earth, others were either abandoned in orbit or intentionally sent to their destruction on the lunar surface. The former now constitute a small population of lunar orbital debris; the latter, including four Lunar Orbiters and four Lunar Module ascent stages, have contributed to nearly 50 lunar sites of man's refuse. Other lunar satellites are known or suspected of having fallen from orbit. Unlike Earth satellite orbital decays and deorbits, lunar satellites impact the lunar surface unscathed by atmospheric burning or melting. Fragmentations of lunar satellites, which would produce clouds of numerous orbital debris, have not yet been detected. The return to lunar orbit in the 1990's by the Hagoromo, Hiten, Clementine, and Lunar Prospector spacecraft and plans for increased lunar exploration early in the 21st century, raise questions of how best to minimize and to dispose of lunar orbital debris. Some of the lessons learned from more than 40 years of Earth orbit exploitation can be applied to the lunar orbital environment. For the near-term, perhaps the most important of these is postmission passivation. Unique solutions, e.g., lunar equatorial dumps, may also prove attractive. However, as with Earth satellites, debris mitigation measures are most effectively adopted early in the concept and design phase, and prevention is less costly than remediation.

  16. Suspected pulmonary tuberculosis in rural South Africa - Sputum ...

    African Journals Online (AJOL)

    Three (125%) of the 24 patients with a discharge diagnosis other than TB (17 pneumonia, 3 old TB, 2 carcinoma of the lung, 1 bronchiectasis) turned out to have TB within the follow-up period; 2 of those had extrapulmonary TB Conclusion, SI produced a positive smear result in 29% of patients with suspected TB who had ...

  17. Orbital computed tomography: technical aspects

    International Nuclear Information System (INIS)

    Beck, T.J.; Rosenbaum, A.E.; Miller, N.R.

    1982-01-01

    Computed tomographic scanning has revolutionized the diagnosis and management of orbital disease. The best use of this methodology requires knowledge of the principles and appropriate attention to scanning protocols. Computed tomographic scanning of the orbit is a demanding technique requiring thin sections through planes precisely positioned from the topographical anatomy. Ideally, orbital CT should include both transverse axial and coronal sections: The pathological condition and its plane of growth will influence the selection of the optimal plane or section. Coronal sections may be obtained either directly or indirectly by computer reconstruction from contiguous transverse images. Sagittal or oblique sections or both also are useful and may be obtained directly or indirectly. Difficulty in patient positioning may preclude direct sagittal imaging, however. The use of intravenous contrast enhancement is not necessary as a routine technique unless a mass is identified or suspected. Where surgical resection or biopsy of a space-occupying lesion is contemplated, contrast enhancement can be valuable in assessing relative vascularity and aiding diagnostic specificity. It should be continually emphasized that CT is a powerful technology which, in orbital diagnosis, produces the highest yield when clinician and radiologist collaborate in the radiodiagnostic workup. The clinical information supplied by the referring ophthalmologist is used by the radiologist both in the selection of the appropriate techniques for investigation and in striving to achieve the most specific conclusion

  18. A NEW TeV BINARY: THE DISCOVERY OF AN ORBITAL PERIOD IN HESS J0632+057

    International Nuclear Information System (INIS)

    Bongiorno, S. D.; Falcone, A. D.; Stroh, M.; Holder, J.; Skilton, J. L.; Hinton, J. A.; Gehrels, N.; Grube, J.

    2011-01-01

    HESS J0632+057 is a variable, point-like source of very high energy (>100 GeV) gamma rays located in the Galactic plane. It is positionally coincident with a Be star, it is a variable radio and X-ray source, has a hard X-ray spectrum, and has low radio flux. These properties suggest that the object may be a member of the rare class of TeV/X-ray binary systems. The definitive confirmation of this would be the detection of a periodic orbital modulation of the flux at any wavelength. We have obtained Swift X-Ray Telescope observations of the source from MJD 54857 to 55647 (2009 January-2011 March) to test the hypothesis that HESS J0632+057 is an X-ray/TeV binary. We show that these data exhibit flux modulation with a period of 321 ± 5 days and we evaluate the significance of this period by calculating the null hypothesis probability, allowing for stochastic flaring. This periodicity establishes the binary nature of HESS J0632+057.

  19. The role of radial nodes of atomic orbitals for chemical bonding and the periodic table.

    Science.gov (United States)

    Kaupp, Martin

    2007-01-15

    The role of radial nodes, or of their absence, in valence orbitals for chemical bonding and periodic trends is discussed from a unified viewpoint. In particular, we emphasize the special role of the absence of a radial node whenever a shell with angular quantum number l is occupied for the first time (lack of "primogenic repulsion"), as with the 1s, 2p, 3d, and 4f shells. Although the consequences of the very compact 2p shell (e.g. good isovalent hybridization, multiple bonding, high electronegativity, lone-pair repulsion, octet rule) are relatively well known, it seems that some of the aspects of the very compact 3d shell in transition-metal chemistry are less well appreciated, e.g., the often weakened and stretched bonds at equilibrium structure, the frequently colored complexes, and the importance of nondynamical electron-correlation effects in bonding. Copyright (c) 2006 Wiley Periodicals, Inc.

  20. Orbital Period Variations in the NY Vir System, Revisited in the Light of New Data

    Directory of Open Access Journals (Sweden)

    Baştürk Özgür

    2018-02-01

    Full Text Available NY Virginis is an eclipsing binary system with a subdwarf B primary and an M type dwarf secondary. Recent studies (Qian et al. 2012; Lee et al. 2014 suggested the presence of two circumbinary planets with a few Jovian masses within the system. Lee et al. (2014 examined the orbital stabilities of the suggested planets, using the best-fit parameters derived from their eclipse timing variation analysis. They found that the outer companion should be ejected from the system in about 800 000 years. An observational report from Pulley et al. (2016 pointed out that the recent mideclipse times of the binary deviate significantly from the models suggested by Lee et al. (2014. In fact, variations in the orbital period of the system had already been recognized by many authors, but the parameters of these variations vary significantly as new data accumulate. Here, we analyze the eclipse timing variations of the NY Vir system, using new mid-eclipse times that we have obtained together with earlier published measurements in order to understand the nature of the system and constrain its parameters.

  1. Orbital melanocytoma: When a tumor becomes a relieving surprise

    Directory of Open Access Journals (Sweden)

    Haytham E. Nasr

    2018-06-01

    Full Text Available Purpose: Melanocytomas are rare pigmented tumors that arise form melanocytes and have been reported in the central nervous system. Orbital melanocytomas “also known as blue nevus” are rarely reported. The occurrence of choroidal melanoma and orbital melanocytomas has never been described. Observations: This is a case of orbital melanocytoma in a 34 year old female who presented with left proptosis and ecchymosis. She has the right eye enucleated to treat a large choroidal melanoma, 6 years earlier. Orbital metastasis was suspected. After orbital imaging and systemic evaluation, incisional biopsy was planned yet the mass could be totally excised and it turned out to be melanocytoma. The condition was not associated with nevus of Ota and the patient is not known to have any predisposing condition for melanocytic lesions. Conclusion and importance: Melanocytoma and malignant melanoma share the same cell of origin. The benign course, the well differentiated cells, absence of anaplasia and the positive reaction to Human Melanoma Black-45 (HMB-45 and S-100 proteins established the diagnosis of the former. Such diagnosis was a relief for this one eyed patient.(HMB-45:human melanoma black-45. Keywords: Orbit, Melanocytoma, Choroidal melanoma, HMB-45, S-100

  2. Unstable periodic orbits and chaotic economic growth

    International Nuclear Information System (INIS)

    Ishiyama, K.; Saiki, Y.

    2005-01-01

    We numerically find many unstable periodic solutions embedded in a chaotic attractor in a macroeconomic growth cycle model of two countries with different fiscal policies, and we focus on a special type of the unstable periodic solutions. It is confirmed that chaotic behavior represented by the model is qualitatively and quantitatively related to the unstable periodic solutions. We point out that the structure of a chaotic solution is dissolved into a class of finite unstable periodic solutions picked out among a large number of periodic solutions. In this context it is essential for the unstable periodic solutions to be embedded in the chaotic attractor

  3. A Typical Presentation of Orbital Pseudotumor Mimicking Orbital Cellulitis

    Directory of Open Access Journals (Sweden)

    J. Ayatollahi

    2013-10-01

    Full Text Available Introduction: Orbital pseudotumor, also known as idiopathic orbital inflammatory syndrome (IOIS, is a benign, non- infective inflammatory condition of the orbit without identifiable local or systemic causes. The disease may mimics a variety of pathologic conditions. We pre-sent a case of pseudotumor observed in a patient admitted under the name of orbital celluli-ties. Case Report: A 26-year-old woman reffered to our hospital with the history of left ocular pain and headache 2 days before her visit.. Ophthalmological examination of the patient was normal except for the redness and lid edema, mild chemosis and conjunctival injection. Gen-eral assessment was normal but a low grade fever was observed. She was hospitalized as an orbital cellulitis patient. She was treated with intravenous antibiotics. On the third day , sud-denly diplopia, proptosis in her left eye and ocular pain in her right side appeared. MRI re-vealed bilateral enlargement of extraocular muscles. Diagnosis of orbital pseudotumor was made and the patient was treated with oral steroid.She responded promptly to the treatment. Antibiotics were discontinued and steroid was tapered in one month period under close fol-low up. Conclusion: The clinical features of orbital pseudotumor vary widely . Orbital pseudotumor and orbital cellulitis can occasionally demonstrate overlapping features.. Despite complete physical examination and appropriate imaging, sometimes correct diagnosis of the disease would be difficult (Sci J Hamadan Univ Med Sci 2013; 20 (3:256-259

  4. Electronic orbital response of regular extended and infinite periodic systems to magnetic fields. I. Theoretical foundations for static case

    Science.gov (United States)

    Springborg, Michael; Molayem, Mohammad; Kirtman, Bernard

    2017-09-01

    A theoretical treatment for the orbital response of an infinite, periodic system to a static, homogeneous, magnetic field is presented. It is assumed that the system of interest has an energy gap separating occupied and unoccupied orbitals and a zero Chern number. In contrast to earlier studies, we do not utilize a perturbation expansion, although we do assume the field is sufficiently weak that the occurrence of Landau levels can be ignored. The theory is developed by analyzing results for large, finite systems and also by comparing with the analogous treatment of an electrostatic field. The resulting many-electron Hamilton operator is forced to be hermitian, but hermiticity is not preserved, in general, for the subsequently derived single-particle operators that determine the electronic orbitals. However, we demonstrate that when focusing on the canonical solutions to the single-particle equations, hermiticity is preserved. The issue of gauge-origin dependence of approximate solutions is addressed. Our approach is compared with several previously proposed treatments, whereby limitations in some of the latter are identified.

  5. THREE PLANETS ORBITING WOLF 1061

    Energy Technology Data Exchange (ETDEWEB)

    Wright, D. J.; Wittenmyer, R. A.; Tinney, C. G.; Bentley, J. S.; Zhao, Jinglin, E-mail: duncan.wright@unsw.edu.au [Department of Astronomy and Australian Centre for Astrobiology, School of Physics, University of New South Wales, NSW 2052 (Australia)

    2016-02-01

    We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M{sub ⊕} minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M{sub ⊕} minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M{sub ⊕} minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H and K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.

  6. PHOTOMETRIC, SPECTROSCOPIC, AND ORBITAL PERIOD STUDY OF THREE EARLY-TYPE SEMI-DETACHED SYSTEMS: XZ AQL, UX HER, AND AT PEG

    Energy Technology Data Exchange (ETDEWEB)

    Zola, S. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, PL-30-244 Krakow (Poland); Baştürk, Ö.; Şenavcı, H. V.; Özavcı, İ.; Yılmaz, M. [Ankara University, Faculty of Science, Department of Astronomy and Space Sciences, Tandoğan, TR-06100, Ankara (Turkey); Liakos, A. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Penteli, Athens (Greece); Gazeas, K. [Department of Astrophysics, Astronomy and Mechanics, National and Kapodistrian University of Athens, Zografos, Athens (Greece); Nelson, R. H. [1393 Garvin Street, Prince George, BC V2M 3Z1 (Canada); Zakrzewski, B., E-mail: szola@oa.uj.edu.pl [Mt Suhora Observatory, Pedagogical University, ul. Podchorazych 2, PL-30-084 Krakow (Poland)

    2016-08-01

    In this paper, we present a combined photometric, spectroscopic, and orbital period study of three early-type eclipsing binary systems: XZ Aql, UX Her, and AT Peg. As a result, we have derived the absolute parameters of their components and, on that basis, we discuss their evolutionary states. Furthermore, we compare their parameters with those of other binary systems and with theoretical models. An analysis of all available up-to-date times of minima indicated that all three systems studied here show cyclic orbital changes; their origin is discussed in detail. Finally, we performed a frequency analysis for possible pulsational behavior, and as a result we suggest that XZ Aql hosts a δ Scuti component.

  7. Replicate periodic windows in the parameter space of driven oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, E.S., E-mail: esm@if.usp.br [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil); Souza, S.L.T. de [Universidade Federal de Sao Joao del-Rei, Campus Alto Paraopeba, Minas Gerais (Brazil); Medrano-T, R.O. [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, Diadema, Sao Paulo (Brazil); Caldas, I.L. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)

    2011-11-15

    Highlights: > We apply a weak harmonic perturbation to control chaos in two driven oscillators. > We find replicate periodic windows in the driven oscillator parameter space. > We find that the periodic window replication is associated with the chaos control. - Abstract: In the bi-dimensional parameter space of driven oscillators, shrimp-shaped periodic windows are immersed in chaotic regions. For two of these oscillators, namely, Duffing and Josephson junction, we show that a weak harmonic perturbation replicates these periodic windows giving rise to parameter regions correspondent to periodic orbits. The new windows are composed of parameters whose periodic orbits have the same periodicity and pattern of stable and unstable periodic orbits already existent for the unperturbed oscillator. Moreover, these unstable periodic orbits are embedded in chaotic attractors in phase space regions where the new stable orbits are identified. Thus, the observed periodic window replication is an effective oscillator control process, once chaotic orbits are replaced by regular ones.

  8. An efficient algorithm for global periodic orbits generation near irregular-shaped asteroids

    Science.gov (United States)

    Shang, Haibin; Wu, Xiaoyu; Ren, Yuan; Shan, Jinjun

    2017-07-01

    Periodic orbits (POs) play an important role in understanding dynamical behaviors around natural celestial bodies. In this study, an efficient algorithm was presented to generate the global POs around irregular-shaped uniformly rotating asteroids. The algorithm was performed in three steps, namely global search, local refinement, and model continuation. First, a mascon model with a low number of particles and optimized mass distribution was constructed to remodel the exterior gravitational potential of the asteroid. Using this model, a multi-start differential evolution enhanced with a deflection strategy with strong global exploration and bypassing abilities was adopted. This algorithm can be regarded as a search engine to find multiple globally optimal regions in which potential POs were located. This was followed by applying a differential correction to locally refine global search solutions and generate the accurate POs in the mascon model in which an analytical Jacobian matrix was derived to improve convergence. Finally, the concept of numerical model continuation was introduced and used to convert the POs from the mascon model into a high-fidelity polyhedron model by sequentially correcting the initial states. The efficiency of the proposed algorithm was substantiated by computing the global POs around an elongated shoe-shaped asteroid 433 Eros. Various global POs with different topological structures in the configuration space were successfully located. Specifically, the proposed algorithm was generic and could be conveniently extended to explore periodic motions in other gravitational systems.

  9. On the trajectories of CRL...LR...R orbits, their period-doubling cascades and saddle-node bifurcation cascades

    International Nuclear Information System (INIS)

    Cerrada, Lucia; San Martin, Jesus

    2011-01-01

    In this Letter, it is shown that from a two region partition of the phase space of a one-dimensional dynamical system, a p-region partition can be obtained for the CRL...LR...R orbits. That is, permutations associated with symbolic sequences are obtained. As a consequence, the trajectory in phase space is directly deduced from permutation. From this permutation other permutations associated with period-doubling and saddle-node bifurcation cascades are derived, as well as other composite permutations. - Research highlights: → Symbolic sequences are the usual topological approach to dynamical systems. → Permutations bear more physical information than symbolic sequences. → Period-doubling cascade permutations associated with original sequences are obtained. → Saddle-node cascade permutations associated with original sequences are obtained. → Composite permutations are derived.

  10. Discovery of a 115 Day Orbital Period in the Ultraluminous X-ray Source NGC 5408 X-1

    Science.gov (United States)

    Strohmayer, Tod E.

    2009-01-01

    We report the detection of a 115 day periodicity in SWIFT/XRT monitoring data from the ultraluminous X-ray source (ULX) NGC 5408 X-1. Our o ngoing campaign samples its X-ray flux approximately twice weekly and has now achieved a temporal baseline of ti 485 days. Periodogram ana lysis reveals a significant periodicity with a period of 115.5 +/- 4 days. The modulation is detected with a significance of 3.2 x 10(exp -4) . The fractional modulation amplitude decreases with increasing e nergy, ranging from 0.13 +/- 0.02 above 1 keV to 0.24 +/- 0.02 below 1 keV. The shape of the profile evolves as well, becoming less sharply peaked at higher energies. The periodogram analysis is consistent wi th a periodic process, however, continued monitoring is required to c onfirm the coherent nature of the modulation. Spectral analysis indic ates that NGC 5408 X-1 can reach 0.3 - 10 keV luminosities of approxi mately 2 x 10 40 ergs/s . We suggest that, like the 62 day period of the ULX in M82 (X41.4-1-60), the periodicity detected in NGC 5408 X-1 represents the orbital period of the black hole binary containing the ULX. If this is true then the secondary can only be a giant or super giant star.

  11. Continuation of Sets of Constrained Orbit Segments

    DEFF Research Database (Denmark)

    Schilder, Frank; Brøns, Morten; Chamoun, George Chaouki

    Sets of constrained orbit segments of time continuous flows are collections of trajectories that represent a whole or parts of an invariant set. A non-trivial but simple example is a homoclinic orbit. A typical representation of this set consists of an equilibrium point of the flow and a trajectory...... that starts close and returns close to this fixed point within finite time. More complicated examples are hybrid periodic orbits of piecewise smooth systems or quasi-periodic invariant tori. Even though it is possible to define generalised two-point boundary value problems for computing sets of constrained...... orbit segments, this is very disadvantageous in practice. In this talk we will present an algorithm that allows the efficient continuation of sets of constrained orbit segments together with the solution of the full variational problem....

  12. Survey of laboratory findings in suspected cases of bovine spongiform encephalopathy in Denmark from 1990 to 2000

    DEFF Research Database (Denmark)

    Agerholm, J.S.; Tegtmeier, C.L.; Nielsen, T.K.

    2002-01-01

    A survey of the laboratory findings in suspected cases of bovine spongiform encephalopathy (BSE) in Denmark from I June 1990 to '31 December 2000 is presented. During this period BSE was a notifiable disease, and the heads of suspected cases were submitted according to the legislation on BSE....... A total of 176 submissions were made, mostly from bovines with neurological disorders and mainly during the last 3 years of this period. Lesions or other laboratory findings consistent with severe neurological disorders were found in 115 cases. The most frequent diagnosis was encephalic 41 p listeriosis...

  13. Planetary perturbations and the origins of short-period comets

    International Nuclear Information System (INIS)

    Quinn, T.; Tremaine, S.; Duncan, M.

    1990-01-01

    To investigate the dynamical plausibility of possible sources for the short-period comets, a representative sample of comet orbits in the field of the sun and the giant planets was integrated, with the aim to determine whether the distribution of orbits from a proposed source that reach observable perihelia (q less than 2.5 AU) matches the observed distribution of short-period orbits. It is found that the majority of the short-period comets, those with orbital period P less than 20 yr (the Jupiter family), cannot arise from isotropic orbits with perihelia near Jupiter's orbit, because the resulting observable comet orbits have the wrong distribution in period, inclination, and argument of perihelion. The simulations also show that Jupiter-family comets cannot arise from isotropic orbits with perihelia in the Uranus-Neptune region. On the other hand, a source of low-inclination Neptune-crossing orbits yields a distribution of observable Jupiter-family comets that is consistent with the data in all respects. These results imply that the Jupiter-family comets arise from a disk source in the outer solar system rather than from the Oort comet cloud. 30 refs

  14. Dynamics of Orbits near 3:1 Resonance in the Earth-Moon System

    Science.gov (United States)

    Dichmann, Donald J.; Lebois, Ryan; Carrico, John P., Jr.

    2013-01-01

    The Interstellar Boundary Explorer (IBEX) spacecraft is currently in a highly elliptical orbit around Earth with a period near 3:1 resonance with the Moon. Its orbit is oriented so that apogee does not approach the Moon. Simulations show this orbit to be remarkably stable over the next twenty years. This article examines the dynamics of such orbits in the Circular Restricted 3-Body Problem (CR3BP). We look at three types of periodic orbits, each exhibiting a type of symmetry of the CR3BP. For each of the orbit types, we assess the local stability using Floquet analysis. Although not all of the periodic solutions are stable in the mathematical sense, any divergence is so slow as to produce practical stability over several decades. We use Poincare maps with twenty-year propagations to assess the nonlinear stability of the orbits, where the perturbation magnitudes are related to the orbit uncertainty for the IBEX mission. Finally we show that these orbits belong to a family of orbits connected in a bifurcation diagram that exhibits exchange of stability. The analysis of these families of period orbits provides a valuable starting point for a mission orbit trade study.

  15. Interaction between subdaily Earth rotation parameters and GPS orbits

    Science.gov (United States)

    Panafidina, Natalia; Seitz, Manuela; Hugentobler, Urs

    2013-04-01

    In processing GPS observations the geodetic parameters like station coordinates and ERPs (Earth rotation parameters) are estimated w.r.t. the celestial reference system realized by the satellite orbits. The interactions/correlations between estimated GPS orbis and other parameters may lead to numerical problems with the solution and introduce systematic errors in the computed values: the well known correlations comprise 1) the correlation between the orbital parameters determining the orientation of the orbital plane in inertial space and the nutation and 2) in the case of estimating ERPs with subdaily resolution the correlation between retrograde diurnal polar motion and nutation (and so the respective orbital elements). In this contribution we study the interaction between the GPS orbits and subdaily model for the ERPs. Existing subdaily ERP model recommended by the IERS comprises ~100 terms in polar motion and ~70 terms in Universal Time at diurnal and semidiurnal tidal periods. We use a long time series of daily normal equation systems (NEQ) obtaine from GPS observations from 1994 till 2007 where the ERPs with 1-hour resolution are transformed into tidal terms and the influence of the tidal terms with different frequencies on the estimated orbital parameters is considered. We found that although there is no algebraic correlation in the NEQ between the individual orbital parameters and the tidal terms, the changes in the amplitudes of tidal terms with periods close to 24 hours can be better accmodated by systematic changes in the orbital parameters than for tidal terms with other periods. Since the variation in Earth rotation with the period of siderial day (23.93h, tide K1) in terrestrial frame has in inertial space the same period as the period of revolution of GPS satellites, the K1 tidal term in polar motion is seen by the satellites as a permanent shift. The tidal terms with close periods (from ~24.13h to ~23.80h) are seen as a slow rotation of the

  16. Harmonically excited orbital variations

    International Nuclear Information System (INIS)

    Morgan, T.

    1985-01-01

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs

  17. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    International Nuclear Information System (INIS)

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-01-01

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods

  18. Thyrotoxic periodic paralysis

    OpenAIRE

    Rojith Karandode Balakrishnan; Suresh Rama Chandran; Geetha Thirumalnesan; Nedumaran Doraisamy

    2011-01-01

    This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recove...

  19. Energy level diagrams for black hole orbits

    Science.gov (United States)

    Levin, Janna

    2009-12-01

    A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.

  20. Energy level diagrams for black hole orbits

    International Nuclear Information System (INIS)

    Levin, Janna

    2009-01-01

    A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.

  1. Application of Semi-analytical Satellite Theory orbit propagator to orbit determination for space object catalog maintenance

    Science.gov (United States)

    Setty, Srinivas J.; Cefola, Paul J.; Montenbruck, Oliver; Fiedler, Hauke

    2016-05-01

    Catalog maintenance for Space Situational Awareness (SSA) demands an accurate and computationally lean orbit propagation and orbit determination technique to cope with the ever increasing number of observed space objects. As an alternative to established numerical and analytical methods, we investigate the accuracy and computational load of the Draper Semi-analytical Satellite Theory (DSST). The standalone version of the DSST was enhanced with additional perturbation models to improve its recovery of short periodic motion. The accuracy of DSST is, for the first time, compared to a numerical propagator with fidelity force models for a comprehensive grid of low, medium, and high altitude orbits with varying eccentricity and different inclinations. Furthermore, the run-time of both propagators is compared as a function of propagation arc, output step size and gravity field order to assess its performance for a full range of relevant use cases. For use in orbit determination, a robust performance of DSST is demonstrated even in the case of sparse observations, which is most sensitive to mismodeled short periodic perturbations. Overall, DSST is shown to exhibit adequate accuracy at favorable computational speed for the full set of orbits that need to be considered in space surveillance. Along with the inherent benefits of a semi-analytical orbit representation, DSST provides an attractive alternative to the more common numerical orbit propagation techniques.

  2. Improving the diagnostic performance of lung scintigraphy in suspected pulmonary embolic disease

    International Nuclear Information System (INIS)

    Gleeson, F.V.; Turner, S.; Scarsbrook, A.F.

    2006-01-01

    Aim: to determine the effectiveness of a new imaging algorithm in the investigation of suspected pulmonary embolism (PE). Materials and methods: A new imaging algorithm for suspected PE was introduced following the installation of a multisection computed tomography (CT) machine at our institution. Before its installation, patients with suspected PE were evaluated with ventilation/perfusion (V/Q) scintigraphy. Subsequently, patients were triaged according to chest radiography (CR) and respiratory history to either lung scintigraphy or CT pulmonary angiography (CTPA). Patients with a normal CR and no history of lung disease were evaluated using perfusion (Q) scintigraphy [ventilation (V) scintigraphy was no longer performed]. Patients with an abnormal CR, asthma or chronic lung disease were evaluated using CTPA. All V/Q images in a continuous 3-year period before the introduction of the new imaging algorithm and all Q images performed in a 3-year period after its introduction were retrospectively reviewed. Imaging reports were categorized into normal, non-diagnostic (low or intermediate probability) or high probability for PE. Patients in the later group who subsequently underwent CTPA, were also reviewed. Results: After the policy change the percentage of normal scintigrams significantly increased (39 to 60%; p < 0.001). There was a non-significant increase in the percentage of high probability scintigrams (15 to 18%; p = 0.716). Overall the diagnostic yield of lung scintigraphy improved significantly (54 to 78%; p < 0.001). Conclusion: the diagnostic performance of lung scintigraphy can be improved by careful triage of patients to either Q scintigraphy or CTPA based on clinical history and CR findings. Q scintigraphy remains a valuable diagnostic test in the investigation of suspected PE in carefully selected patients

  3. Orbital structure in oscillating galactic potentials

    Science.gov (United States)

    Terzić, Balša; Kandrup, Henry E.

    2004-01-01

    Subjecting a galactic potential to (possibly damped) nearly periodic, time-dependent variations can lead to large numbers of chaotic orbits experiencing systematic changes in energy, and the resulting chaotic phase mixing could play an important role in explaining such phenomena as violent relaxation. This paper focuses on the simplest case of spherically symmetric potentials subjected to strictly periodic driving with the aim of understanding precisely why orbits become chaotic and under what circumstances they will exhibit systematic changes in energy. Four unperturbed potentials V0(r) were considered, each subjected to a time dependence of the form V(r, t) =V0(r)(1 +m0 sinωt). In each case, the orbits divide clearly into regular and chaotic, distinctions which appear absolute. In particular, transitions from regularity to chaos are seemingly impossible. Over finite time intervals, chaotic orbits subdivide into what can be termed `sticky' chaotic orbits, which exhibit no large-scale secular changes in energy and remain trapped in the phase-space region where they started; and `wildly' chaotic orbits, which do exhibit systematic drifts in energy as the orbits diffuse to different phase-space regions. This latter distinction is not absolute, transitions corresponding apparently to orbits penetrating a `leaky' phase-space barrier. The three different orbit types can be identified simply in terms of the frequencies for which their Fourier spectra have the most power. An examination of the statistical properties of orbit ensembles as a function of driving frequency ω allows us to identify the specific resonances that determine orbital structure. Attention focuses also on how, for fixed amplitude m0, such quantities as the mean energy shift, the relative measure of chaotic orbits and the mean value of the largest Lyapunov exponent vary with driving frequency ω and how, for fixed ω, the same quantities depend on m0.

  4. Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter

    Science.gov (United States)

    Bae, Jonghee; Song, Young-Joo; Kim, Young-Rok; Kim, Bangyeop

    2017-12-01

    The first Korea lunar orbiter, Korea Pathfinder Lunar Orbiter (KPLO), has been in development since 2016. After launch, the KPLO will execute several maneuvers to enter into the lunar mission orbit, and will then perform lunar science missions for one year. Among these maneuvers, the lunar orbit insertion (LOI) is the most critical maneuver because the KPLO will experience an extreme velocity change in the presence of the Moon’s gravitational pull. However, the lunar orbiter may have a delayed LOI burn during operation due to hardware limitations and telemetry delays. This delayed burn could occur in different captured lunar orbits; in the worst case, the KPLO could fly away from the Moon. Therefore, in this study, the burn delay for the first LOI maneuver is analyzed to successfully enter the desired lunar orbit. Numerical simulations are performed to evaluate the difference between the desired and delayed lunar orbits due to a burn delay in the LOI maneuver. Based on this analysis, critical factors in the LOI maneuver, the periselene altitude and orbit period, are significantly changed and an additional delta-V in the second LOI maneuver is required as the delay burn interval increases to 10 min from the planned maneuver epoch.

  5. Guidelines for identifying suspect/counterfeit material

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    These guidelines are intended to assist users of products in identifying: substandard, misrepresented, or fraudulently marked items. The guidelines provide information about such topics as: precautions, inspection and testing, dispositioning identified items, installed inspection and reporting suspect/counterfeit materials. These guidelines apply to users who are developing procurement documents, product acceptance/verification methods, company procedures, work instructions, etc. The intent of these SM guidelines in relation to the Quality Assurance Program Description (QAPD) and implementing company Management Control Procedures is not to substitute or replace existing requirements, as defined in either the QAPD or company implementing instructions (Management Control Procedures). Instead, the guidelines are intended to provide a consolidated source of information addressing the issue of Suspect/Counterfeit materials. These guidelines provide an extensive suspect component listing and suspect indications listing. Users can quickly check their suspect items against the list of manufacturers products (i.e., type, LD. number, and nameplate information) by consulting either of these listings.

  6. LONG-ORBITAL-PERIOD PREPOLARS CONTAINING EARLY K-TYPE DONOR STARS. BOTTLENECK ACCRETION MECHANISM IN ACTION

    International Nuclear Information System (INIS)

    Tovmassian, G.; González–Buitrago, D.; Zharikov, S.; Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P.; Miroshnichenko, A. S.

    2016-01-01

    We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems

  7. LONG-ORBITAL-PERIOD PREPOLARS CONTAINING EARLY K-TYPE DONOR STARS. BOTTLENECK ACCRETION MECHANISM IN ACTION

    Energy Technology Data Exchange (ETDEWEB)

    Tovmassian, G.; González–Buitrago, D.; Zharikov, S. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 877, Ensenada, Baja California, 22800 México (Mexico); Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Campus Box 3255, Chapel Hill, NC 27599 (United States); Miroshnichenko, A. S., E-mail: gag@astro.unam.mx, E-mail: dgonzalez@astro.unam.mx, E-mail: zhar@astro.unam.mx [Department of Physics and Astronomy, University of North Carolina at Greensboro, Greensboro, NC 27402-6170 (United States)

    2016-03-01

    We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems.

  8. Gravitational waves from periodic three-body systems.

    Science.gov (United States)

    Dmitrašinović, V; Suvakov, Milovan; Hudomal, Ana

    2014-09-05

    Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values.

  9. On the lunar node resonance of the orbital plane evolution of the Earth's satellite orbits

    Science.gov (United States)

    Zhu, Ting-Lei

    2018-06-01

    This paper aims to investigate the effects of lunar node resonance on the circular medium Earth orbits (MEO). The dynamical model is established in classical Hamiltonian systems with the application of Lie transform to remove the non-resonant terms. Resonant condition, stability and phase structures are studied. The lunar node resonance occurs when the secular changing rates of the orbital node (with respect to the equator) and the lunar node (with respect to the ecliptic) form a simple integer ratio. The resonant conditions are satisfied for both inclined and equatorial orbits. The orbital plane would have long period (with typical timescales of several centuries) fluctuation due to the resonance.

  10. Imaging trends in suspected appendicitis-a Canadian perspective.

    Science.gov (United States)

    Tan, Victoria F; Patlas, Michael N; Katz, Douglas S

    2017-06-01

    The purpose of our study was to assess trends in the imaging of suspected appendicitis in adult patients in emergency departments of academic centers in Canada. A questionnaire was sent to all 17 academic centers in Canada to be completed by a radiologist who works in emergency radiology. The questionnaires were sent and collected over a period of 4 months from October 2015 to February 2016. Sixteen centers (94%) responded to the questionnaire. Eleven respondents (73%) use IV contrast-enhanced computed tomography (CT) as the imaging modality of choice for all patients with suspected appendicitis. Thirteen respondents (81%) use ultrasound as the first modality of choice in imaging pregnant patients with suspected appendicitis. Eleven respondents (69%) use ultrasound (US) as the first modality of choice in patients younger than 40 years of age. Ten respondents (67%) use ultrasound as the first imaging modality in female patients younger than 40 years of age. When CT is used, 81% use non-focused CT of the abdomen and pelvis, and 44% of centers use oral contrast. Thirteen centers (81%) have ultrasound available 24 h a day/7 days a week. At 12 centers (75%), ultrasound is performed by ultrasound technologists. Four centers (40%) perform magnetic resonance imaging (MRI) in suspected appendicitis in adult patients at the discretion of the attending radiologist. Eleven centers (69%) have MRI available 24/7. All 16 centers (100%) use unenhanced MRI. Various imaging modalities are available for the work-up of suspected appendicitis. Although there are North American societal guidelines and recommendations regarding the appropriateness of the multiple imaging modalities, significant heterogeneity in the first-line modalities exist, which vary depending on the patient demographics and resource availability. Imaging trends in the use of the first-line modalities should be considered in order to plan for the availability of the imaging examinations and to consider plans for

  11. Pumped double quantum dot with spin-orbit coupling

    Directory of Open Access Journals (Sweden)

    Sherman Eugene

    2011-01-01

    Full Text Available Abstract We study driven by an external electric field quantum orbital and spin dynamics of electron in a one-dimensional double quantum dot with spin-orbit coupling. Two types of external perturbation are considered: a periodic field at the Zeeman frequency and a single half-period pulse. Spin-orbit coupling leads to a nontrivial evolution in the spin and orbital channels and to a strongly spin- dependent probability density distribution. Both the interdot tunneling and the driven motion contribute into the spin evolution. These results can be important for the design of the spin manipulation schemes in semiconductor nanostructures. PACS numbers: 73.63.Kv,72.25.Dc,72.25.Pn

  12. New binary pulsar in a highy eccentric orbit

    International Nuclear Information System (INIS)

    Stokes, G.H.; Taylor, J.H.; Dewey, R.J.

    1985-01-01

    We report the discovery of PSR 2303+46, the fifth radio pulsar known to be in a gravitationally bound orbit around another star. The pulsar period (1.066 s) and the orbital eccentricity (0.658) are the largest amount the five binary systems, while the orbital period (12./sup d/34) lies near the middle of the range. Evolutionary considerations suggest strongly that the companion is another neutron star. The general relativistic precession of periastron should be observable within 1 or 2 yr and, when measured, will specify the total mass of the two stars

  13. Theory of orbital magnetoelectric response

    International Nuclear Information System (INIS)

    Malashevich, Andrei; Souza, Ivo; Coh, Sinisa; Vanderbilt, David

    2010-01-01

    We extend the recently developed theory of bulk orbital magnetization to finite electric fields, and use it to calculate the orbital magnetoelectric (ME) response of periodic insulators. Working in the independent-particle framework, we find that the finite-field orbital magnetization can be written as a sum of three gauge-invariant contributions, one of which has no counterpart at zero field. The extra contribution is collinear with and explicitly dependent on the electric field. The expression for the orbital magnetization is suitable for first-principles implementations, allowing one to calculate the ME response coefficients by numerical differentiation. Alternatively, perturbation-theory techniques may be used, and for that purpose we derive an expression directly for the linear ME tensor by taking the first field-derivative analytically. Two types of terms are obtained. One, the 'Chern-Simons' term, depends only on the unperturbed occupied orbitals and is purely isotropic. The other, 'Kubo' terms, involve the first-order change in the orbitals and give isotropic as well as anisotropic contributions to the response. In ordinary ME insulators all terms are generally present, while in strong Z 2 topological insulators only the Chern-Simons term is allowed, and is quantized. In order to validate the theory, we have calculated under periodic boundary conditions the linear ME susceptibility for a 3D tight-binding model of an ordinary ME insulator, using both the finite-field and perturbation-theory expressions. The results are in excellent agreement with calculations on bounded samples.

  14. Robustness analysis method for orbit control

    Science.gov (United States)

    Zhang, Jingrui; Yang, Keying; Qi, Rui; Zhao, Shuge; Li, Yanyan

    2017-08-01

    Satellite orbits require periodical maintenance due to the presence of perturbations. However, random errors caused by inaccurate orbit determination and thrust implementation may lead to failure of the orbit control strategy. Therefore, it is necessary to analyze the robustness of the orbit control methods. Feasible strategies which are tolerant to errors of a certain magnitude can be developed to perform reliable orbit control for the satellite. In this paper, first, the orbital dynamic model is formulated by Gauss' form of the planetary equation using the mean orbit elements; the atmospheric drag and the Earth's non-spherical perturbations are taken into consideration in this model. Second, an impulsive control strategy employing the differential correction algorithm is developed to maintain the satellite trajectory parameters in given ranges. Finally, the robustness of the impulsive control method is analyzed through Monte Carlo simulations while taking orbit determination error and thrust error into account.

  15. The Eccentric Behavior of Nearly Frozen Orbits

    Science.gov (United States)

    Sweetser, Theodore H.; Vincent, Mark A.

    2013-01-01

    Frozen orbits are orbits which have only short-period changes in their mean eccentricity and argument of periapse, so that they basically keep a fixed orientation within their plane of motion. Nearly frozen orbits are those whose eccentricity and argument of periapse have values close to those of a frozen orbit. We call them "nearly" frozen because their eccentricity vector (a vector whose polar coordinates are eccentricity and argument of periapse) will stay within a bounded distance from the frozen orbit eccentricity vector, circulating around it over time. For highly inclined orbits around the Earth, this distance is effectively constant over time. Furthermore, frozen orbit eccentricity values are low enough that these orbits are essentially eccentric (i.e., off center) circles, so that nearly frozen orbits around Earth are bounded above and below by frozen orbits.

  16. An Orbit Propagation Software for Mars Orbiting Spacecraft

    Directory of Open Access Journals (Sweden)

    Young-Joo Song

    2004-12-01

    Full Text Available An orbit propagation software for the Mars orbiting spacecraft has been developed and verified in preparations for the future Korean Mars missions. Dynamic model for Mars orbiting spacecraft has been studied, and Mars centered coordinate systems are utilized to express spacecraft state vectors. Coordinate corrections to the Mars centered coordinate system have been made to adjust the effects caused by Mars precession and nutation. After spacecraft enters Sphere of Influence (SOI of the Mars, the spacecraft experiences various perturbation effects as it approaches to Mars. Every possible perturbation effect is considered during integrations of spacecraft state vectors. The Mars50c gravity field model and the Mars-GRAM 2001 model are used to compute perturbation effects due to Mars gravity field and Mars atmospheric drag, respectively. To compute exact locations of other planets, JPL's DE405 ephemerides are used. Phobos and Deimos's ephemeris are computed using analytical method because their informations are not released with DE405. Mars Global Surveyor's mapping orbital data are used to verify the developed propagator performances. After one Martian day propagation (12 orbital periods, the results show about maximum ±5 meter errors, in every position state components(radial, cross-track and along-track, when compared to these from the Astrogator propagation in the Satellite Tool Kit. This result shows high reliability of the developed software which can be used to design near Mars missions for Korea, in future.

  17. Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking*

    Science.gov (United States)

    Hamed, Kaveh Akbari; Gregg, Robert D.

    2016-01-01

    This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:27990059

  18. Changing spin-orbit interaction with increasing exoticism across the periodic table

    International Nuclear Information System (INIS)

    Kshetri, Ritesh; Ray, Indrani; Saha Sarkar, M.; Sarkar, Sukhendusekhar

    2005-01-01

    Recently, experimental information about nuclei away from the valley of stability are being available. Several workers have suggested that shell structures may change away from the line of stability and nuclear spin-orbit interaction weakens as a function of the neutron excess

  19. International Suspect Screening: NORMAN Suspect Exchange meets the US EPA CompTox Chemistry Dashboard (ICCE 2017 Oslo)

    Science.gov (United States)

    Members of the European NORMAN Network of Environmental Laboratories (www.norman-network.com) have many substance lists, including targets, suspects, surfactants, perfluorinated substances and regulated, partially confidential data sets of complex mixtures. The NORMAN Suspect Lis...

  20. Sticky orbits in a kicked-oscillator model

    CERN Document Server

    Lowenstein, J H; Vivaldi, F

    2005-01-01

    We study a 4-fold symmetric kicked-oscillator map with sawtooth kick function. For the values of the kick amplitude $\\lambda=2\\cos(2\\pi p/q)$ with rational $p/q$, the dynamics is known to be pseudochaotic, with no stochastic web of non-zero Lebesgue measure. We show that this system can be represented as a piecewise affine map of the unit square ---the so-called local map--- driving a lattice map. We develop a framework for the study of long-time behaviour of the orbits, in the case in which the local map features exact scaling. We apply this method to several quadratic irrational values of $\\lambda$, for which the local map possesses a full Legesgue measure of periodic orbits; these are promoted to either periodic orbits or accelerator modes of the kicked-oscillator map. By constrast, the aperiodic orbits of the local map can generate various asymptotic behaviours. For some parameter values the orbits remain bounded, while others have excursions which grow logarithmically or as a power of the time. In the po...

  1. QATAR-2: A K DWARF ORBITED BY A TRANSITING HOT JUPITER AND A MORE MASSIVE COMPANION IN AN OUTER ORBIT

    International Nuclear Information System (INIS)

    Bryan, Marta L.; Alsubai, Khalid A.; Latham, David W.; Quinn, Samuel N.; Carter, Joshua A.; Berlind, Perry; Brown, Warren R.; Calkins, Michael L.; Esquerdo, Gilbert A.; Fűrész, Gábor; Stefanik, Robert P.; Torres, Guillermo; Parley, Neil R.; Collier Cameron, Andrew; Horne, Keith D.; Fulton, Benjamin J.; Street, Rachel A.; Buchhave, Lars A.; Jørgensen, Uffe Gråe; West, Richard G.

    2012-01-01

    We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short period, P b = 1.34 days. The mass and radius of Qatar-2b are M P = 2.49 M J and R P = 1.14 R J , respectively. Radial-velocity monitoring of Qatar-2 over a span of 153 days revealed the presence of a second companion in an outer orbit. The Systemic Console yielded plausible orbits for the outer companion, with periods on the order of a year and a companion mass of at least several M J . Thus, Qatar-2 joins the short but growing list of systems with a transiting hot Jupiter and an outer companion with a much longer period. This system architecture is in sharp contrast to that found by Kepler for multi-transiting systems, which are dominated by objects smaller than Neptune, usually with tightly spaced orbits that must be nearly coplanar.

  2. Methods of orbit correction system optimization

    International Nuclear Information System (INIS)

    Chao, Yu-Chiu.

    1997-01-01

    Extracting optimal performance out of an orbit correction system is an important component of accelerator design and evaluation. The question of effectiveness vs. economy, however, is not always easily tractable. This is especially true in cases where betatron function magnitude and phase advance do not have smooth or periodic dependencies on the physical distance. In this report a program is presented using linear algebraic techniques to address this problem. A systematic recipe is given, supported with quantitative criteria, for arriving at an orbit correction system design with the optimal balance between performance and economy. The orbit referred to in this context can be generalized to include angle, path length, orbit effects on the optical transfer matrix, and simultaneous effects on multiple pass orbits

  3. Long-Term Prediction of Satellite Orbit Using Analytical Method

    Directory of Open Access Journals (Sweden)

    Jae-Cheol Yoon

    1997-12-01

    Full Text Available A long-term prediction algorithm of geostationary orbit was developed using the analytical method. The perturbation force models include geopotential upto fifth order and degree and luni-solar gravitation, and solar radiation pressure. All of the perturbation effects were analyzed by secular variations, short-period variations, and long-period variations for equinoctial elements such as the semi-major axis, eccentricity vector, inclination vector, and mean longitude of the satellite. Result of the analytical orbit propagator was compared with that of the cowell orbit propagator for the KOREASAT. The comparison indicated that the analytical solution could predict the semi-major axis with an accuarcy of better than ~35meters over a period of 3 month.

  4. Spooky Suspects

    Science.gov (United States)

    Pacifici, Lara

    2011-01-01

    This activity presents an option for covering biology content while engaging students in an investigation that highlights the spirit of Halloween. Students are engaged in the story line and have fun trying to solve the mystery kidnapping by using science skills to examine the evidence and eliminate some ghoulish suspects. (Contains 1 figure.)

  5. Modification of an impulse-factoring orbital transfer technique to account for orbit determination and maneuver execution errors

    Science.gov (United States)

    Kibler, J. F.; Green, R. N.; Young, G. R.; Kelly, M. G.

    1974-01-01

    A method has previously been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The method uses impulse factoring in which a two-impulse transfer is divided into three or four impulses which add one or two intermediate orbits. The periods of the intermediate orbits and the number of revolutions in each orbit are varied to satisfy timing constraints. Techniques are developed to retarget the orbital transfer in the presence of orbit-determination and maneuver-execution errors. Sample results indicate that the nominal transfer can be retargeted with little change in either the magnitude (Delta V) or location of the individual impulses. Additonally, the total Delta V required for the retargeted transfer is little different from that required for the nominal transfer. A digital computer program developed to implement the techniques is described.

  6. Attempt to compare two arc orbit correction schemes analytically

    International Nuclear Information System (INIS)

    Chao, A.; Weng, W.

    1983-01-01

    Consider a transport line that consists of periodic cells. Let the beam position monitors and the orbit correctors be located with the same period as the cells and let the BPM's and the corrector distributions interlace each other. The arrangement does not always provide a stable orbit correction. The criterion for stability has been derived by Joe Murray and is reproduced. We calculate the rms orbit, the effect of BPM errors and the rms corrector strength in such correction schemes, yielding analytic formulae for these quantities. We then apply these formulae to the SLC arcs

  7. Small-bowel capsule endoscopy in patients with suspected Crohn's disease-diagnostic value and complications.

    Science.gov (United States)

    Figueiredo, Pedro; Almeida, Nuno; Lopes, Sandra; Duque, Gabriela; Freire, Paulo; Lérias, Clotilde; Gouveia, Hermano; Sofia, Carlos

    2010-01-01

    The aim of this work was to assess the value of capsule enteroscopy in the diagnosis of patients with suspected Crohn's Disease (CD). Methods. This was a retrospective study in a single tertiary care centre involving patients undergoing capsule enteroscopy for suspected CD. Patients taking nonsteroidal anti inflammatory drugs during the thirty preceding days or with a follow-up period of less than six months were excluded. Results. Seventy eight patients were included. The endoscopic findings included mucosal breaks in 50%, ulcerated stenosis in 5%, and villous atrophy in 4%. The diagnosis of CD was established in 31 patients. The sensitivity, specificity, positive and negative predictive value of the endoscopic findings were 93%, 80%, 77%, and 94%, respectively. Capsule retention occurred in four patients (5%). The presence of ulcerated stenosis was significantly more frequent in patients with positive inflammatory markers. The diagnostic yield of capsule enteroscopy in patients with negative ileoscopy was 56%, with a diagnostic acuity of 93%. Small bowel capsule endoscopy is a safe and valid technique for assessing patients with suspected CD. Capsule retention is more frequent in patients with positive inflammatory markers. Patients with negative ileoscopy and suspected CD should be submitted to capsule enteroscopy.

  8. Lineup composition, suspect position, and the sequential lineup advantage.

    Science.gov (United States)

    Carlson, Curt A; Gronlund, Scott D; Clark, Steven E

    2008-06-01

    N. M. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001) argued that sequential lineups reduce the likelihood of mistaken eyewitness identification. Experiment 1 replicated the design of R. C. L. Lindsay and G. L. Wells (1985), the first study to show the sequential lineup advantage. However, the innocent suspect was chosen at a lower rate in the simultaneous lineup, and no sequential lineup advantage was found. This led the authors to hypothesize that protection from a sequential lineup might emerge only when an innocent suspect stands out from the other lineup members. In Experiment 2, participants viewed a simultaneous or sequential lineup with either the guilty suspect or 1 of 3 innocent suspects. Lineup fairness was varied to influence the degree to which a suspect stood out. A sequential lineup advantage was found only for the unfair lineups. Additional analyses of suspect position in the sequential lineups showed an increase in the diagnosticity of suspect identifications as the suspect was placed later in the sequential lineup. These results suggest that the sequential lineup advantage is dependent on lineup composition and suspect position. (c) 2008 APA, all rights reserved

  9. Local orbit feedback

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Critically aligned experiments are sensitive to small changes in the electron beam orbit. At the NSLS storage rings, the electron beam and photon beam motions have been monitored over the past several years. In the survey conducted in 1986 by the NSLS Users Executive Committee, experimenters requested the vertical beam position variation and the vertical angle variation, within a given fill, remain within 10 μm and 10 μr, respectively. This requires improvement in the beam stability by about one order of magnitude. At the NSLS and SSRL storage rings, the beam that is originally centered on the position monitor by a dc orbit correction is observed to have two kinds of motion: a dc drift over a storage period of several hours and a beam bounce about its nominal position. These motions are a result of the equilibrium orbit not being held perfectly stable due to time-varying errors introduced into the magnetic guide field by power supplies, mechanical vibration of the magnets, cooling water temperature variations, etc. The approach to orbit stabilization includes (1) identifying and suppressing as many noise sources on the machine as possible, (2) correcting the beam position globally (see Section 6) by controlling a number of correctors around the circumference of the machine, and (3) correcting the beam position and angle at a given source location by position feedback using local detectors and local orbit bumps. The third approach, called Local Orbit Feedback will be discussed in this section

  10. ExoMars Trace Gas Orbiter provides atmospheric data during Aerobraking into its final orbit

    Science.gov (United States)

    Svedhem, Hakan; Vago, Jorge L.; Bruinsma, Sean; Müller-Wodarg, Ingo; ExoMars 2016 Team

    2017-10-01

    After the arrival of the Trace Gas Orbiter (TGO) at Mars on 19 October 2016 a number of initial orbit change manoeuvres were executed and the spacecraft was put in an orbit with a 24 hour period and 74 degrees inclination. The spacecraft and its four instruments were thoroughly checked out after arrival and a few measurements and images were taken in November 2016 and in Feb-March 2017. The solar occultation observations have however not yet been possible due to lack of the proper geometry.On 15 March a long period of aerobraking to reach the final 400km semi-circular frozen orbit (370x430km, with a fixed pericentre latitude). This orbit is optimised for the payload observations and for the communication relay with the ExoMars Rover, due to arrive in 2021.The aerobraking is proceeding well and the final orbit is expected to be reached in April 2018. A large data set is being acquired for the upper atmosphere of Mars, from the limit of the sensitivity of the accelerometer, down to lowest altitude of the aerobraking at about 105km. Initial analysis has shown a highly variable atmosphere with a slightly lower density then predicted by existing models. Until the time of the abstract writing no dust storms have been observed.The ExoMars programme is a joint activity by the European Space Agency(ESA) and ROSCOSMOS, Russia. ESA is providing the TGO spacecraft and Schiaparelli (EDM) and two of the TGO instruments and ROSCOSMOS is providing the Proton launcher and the other two TGO instruments. After the arrival of the ExoMars 2020 mission, consisting of a Rover and a Surface platform also launched by a Proton rocket, the TGO will handle the communication between the Earth and the Rover and Surface Platform through its (NASA provided) UHF communication system.

  11. Microscopic Stern-Gerlach effect and spin-orbit pendulum

    International Nuclear Information System (INIS)

    Rozmej, P.; Arvieu, R.

    1996-01-01

    The motion of a particle with spin in spherical harmonic oscillator potential with spin-orbit interaction is discussed. The attention is focused on the spatial motion of wave packets. The particular case of wave packets moving along the circular orbits for which the most transparent and pedagogical description is possible is considered. The splitting of the wave packets into two components moving differently along classical orbits reflects a strong analogy with the Stern-Gerlach experiment. The periodic transfer of average angular momentum between spin and orbital subspaces accompanying this time evolution is called the spin-orbit pendulum. (author). 6 refs, 3 figs

  12. Seasonal variation among tuberculosis suspects in four countries

    DEFF Research Database (Denmark)

    Mabaera, Biggie; Naranbat, Nymadawa; Katamba, Achilles

    2009-01-01

    The objective of the study was to analyze monthly trends across a calendar year in tuberculosis suspects and sputum smear-positive cases based on nationally representative samples of tuberculosis laboratory registers from Moldova, Mongolia, Uganda and Zimbabwe. Out of the 47 140 suspects registered...... in the tuberculosis laboratory registers, 13.4% (6312) were cases. The proportion varied from country to country, Moldova having the lowest (9%) and Uganda the highest (21%). From the monthly proportion of suspects and cases among total suspects and cases, seasonal variations were most marked in Mongolia which, among...... attendance to diagnostic laboratory services, evidenced by the contrasting findings of Mongolia (extreme continental northern climate) compared to Uganda (equatorial climate). A combination of external and possibly endogenous factors seems to determine whether tuberculosis suspects and cases present...

  13. Selecting foils for identification lineups: matching suspects or descriptions?

    Science.gov (United States)

    Tunnicliff, J L; Clark, S E

    2000-04-01

    Two experiments directly compare two methods of selecting foils for identification lineups. The suspect-matched method selects foils based on their match to the suspect, whereas the description-matched method selects foils based on their match to the witness's description of the perpetrator. Theoretical analyses and previous results predict an advantage for description-matched lineups both in terms of correctly identifying the perpetrator and minimizing false identification of innocent suspects. The advantage for description-matched lineups should be particularly pronounced if the foils selected in suspect-matched lineups are too similar to the suspect. In Experiment 1, the lineups were created by trained police officers, and in Experiment 2, the lineups were constructed by undergraduate college students. The results of both experiments showed higher suspect-to-foil similarity for suspect-matched lineups than for description-matched lineups. However, neither experiment showed a difference in correct or false identification rates. Both experiments did, however, show that there may be an advantage for suspect-matched lineups in terms of no-pick and rejection responses. From these results, the endorsement of one method over the other seems premature.

  14. Bi-periodicity evoked by periodic external inputs in delayed Cohen-Grossberg-type bidirectional associative memory networks

    Science.gov (United States)

    Cao, Jinde; Wang, Yanyan

    2010-05-01

    In this paper, the bi-periodicity issue is discussed for Cohen-Grossberg-type (CG-type) bidirectional associative memory (BAM) neural networks (NNs) with time-varying delays and standard activation functions. It is shown that the model considered in this paper has two periodic orbits located in saturation regions and they are locally exponentially stable. Meanwhile, some conditions are derived to ensure that, in any designated region, the model has a locally exponentially stable or globally exponentially attractive periodic orbit located in it. As a special case of bi-periodicity, some results are also presented for the system with constant external inputs. Finally, four examples are given to illustrate the effectiveness of the obtained results.

  15. Bi-periodicity evoked by periodic external inputs in delayed Cohen-Grossberg-type bidirectional associative memory networks

    International Nuclear Information System (INIS)

    Cao Jinde; Wang Yanyan

    2010-01-01

    In this paper, the bi-periodicity issue is discussed for Cohen-Grossberg-type (CG-type) bidirectional associative memory (BAM) neural networks (NNs) with time-varying delays and standard activation functions. It is shown that the model considered in this paper has two periodic orbits located in saturation regions and they are locally exponentially stable. Meanwhile, some conditions are derived to ensure that, in any designated region, the model has a locally exponentially stable or globally exponentially attractive periodic orbit located in it. As a special case of bi-periodicity, some results are also presented for the system with constant external inputs. Finally, four examples are given to illustrate the effectiveness of the obtained results.

  16. Quantum mechanical analysis of the equilateral triangle billiard: Periodic orbit theory and wave packet revivals

    International Nuclear Information System (INIS)

    Doncheski, M.A.; Robinett, R.W.

    2002-01-01

    Using the fact that the energy eigenstates of the equilateral triangle infinite well (or billiard) are available in closed form, we examine the connections between the energy eigenvalue spectrum and the classical closed paths in this geometry, using both periodic orbit theory and the short-term semi-classical behavior of wave packets. We also discuss wave packet revivals and show that there are exact revivals, for all wave packets, at times given by T rev =9μa 2 /4(h/2π) where a and μ are the length of one side and the mass of the point particle, respectively. We find additional cases of exact revivals with shorter revival times for zero-momentum wave packets initially located at special symmetry points inside the billiard. Finally, we discuss simple variations on the equilateral (60 deg. -60 deg. -60 deg. ) triangle, such as the half equilateral (30 deg. -60 deg. -90 deg.) triangle and other 'foldings', which have related energy spectra and revival structures

  17. Comparison of clinically suspected injuries with injuries detected at whole-body CT in suspected multi-trauma victims

    International Nuclear Information System (INIS)

    Shannon, L.; Peachey, T.; Skipper, N.; Adiotomre, E.; Chopra, A.; Marappan, B.; Kotnis, N.

    2015-01-01

    Aim: To assess the accuracy of the trauma team leader's clinical suspicion of injury in patients who have undergone whole-body computed tomography (WBCT) for suspected polytrauma, and to assess the frequency of unsuspected injuries and specific patterns of injury at WBCT. Materials and methods: Requests for patients who underwent WBCT for suspected polytrauma from April 2011 to March 2014 were reviewed and each body area that was clinically suspected to be injured was recorded. Body areas were divided into the following groups based on anatomical regions covered in each segment of the WBCT examination: head (including facial bones); neck (including cervical spine); chest (including thoracic spine); and abdomen/pelvis (including lumbar spine). The formal radiology report for each study was reviewed and injuries found at CT were grouped into the same body areas. For each patient, the number of clinically suspected injured areas was compared to the number of confirmed injured areas at WBCT. Results: Five hundred and eighty-eight patients were included in the study. Thirty-two percent (186/588) had a normal scan. Ninety-three percent (546/588) had fewer injured body areas at WBCT than suspected. Four percent (27/588) had the equivalent number of injured areas at WBCT as suspected. Three percent (15/588) had more injured areas at WBCT than suspected. Fifty percent (263/527) with clinically suspected chest injuries were confirmed to have chest injuries at WBCT. This was lower for other areas: abdomen/pelvis 31% (165/535); head 29% (155/533); neck 13% (66/513). Four percent of (24/588) patients had unsuspected injuries found at WBCT. Seventy-five percent (18/24) of unsuspected injuries were considered as serious, where failure to treat would have the potential for significant morbidity. Most of these patients had severe injuries to other body areas that were correctly suspected. Of the 165 with abdominal/pelvic region injuries, there were associated injuries in the

  18. On the Dynamics of a Model with Coexistence of Three Attractors: A Point, a Periodic Orbit and a Strange Attractor

    Energy Technology Data Exchange (ETDEWEB)

    Llibre, Jaume, E-mail: jllibre@mat.uab.cat [Universitat Autònoma de Barcelona, Departament de Matemàtiques (Spain); Valls, Claudia, E-mail: cvalls@math.ist.utl.pt [Universidade de Lisboa, Departamento de Matemática, Instituto Superior Técnico (Portugal)

    2017-06-15

    For a dynamical system described by a set of autonomous differential equations, an attractor can be either a point, or a periodic orbit, or even a strange attractor. Recently a new chaotic system with only one parameter has been presented where besides a point attractor and a chaotic attractor, it also has a coexisting attractor limit cycle which makes evident the complexity of such a system. We study using analytic tools the dynamics of such system. We describe its global dynamics near the infinity, and prove that it has no Darboux first integrals.

  19. THE NASA-UC ETA-EARTH PROGRAM. III. A SUPER-EARTH ORBITING HD 97658 AND A NEPTUNE-MASS PLANET ORBITING Gl 785

    International Nuclear Information System (INIS)

    Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard; Johnson, John Asher; Fischer, Debra A.; Wright, Jason T.; Henry, Gregory W.; Valenti, Jeff A.; Anderson, Jay; Piskunov, Nikolai E.

    2011-01-01

    We report the discovery of planets orbiting two bright, nearby early K dwarf stars, HD 97658 and Gl 785. These planets were detected by Keplerian modeling of radial velocities measured with Keck-HIRES for the NASA-UC Eta-Earth Survey. HD 97658 b is a close-in super-Earth with minimum mass Msin i = 8.2 ± 1.2 M + , orbital period P = 9.494 ± 0.005 days, and an orbit that is consistent with circular. Gl 785 b is a Neptune-mass planet with Msin i = 21.6 ± 2.0 M + , P = 74.39 ± 0.12 days, and orbital eccentricity e = 0.30 ± 0.09. Photometric observations with the T12 0.8 m automatic photometric telescope at Fairborn Observatory show that HD 97658 is photometrically constant at the radial velocity period to 0.09 mmag, supporting the existence of the planet.

  20. Small-Bowel Capsule Endoscopy in Patients with Suspected Crohn's Disease—Diagnostic Value and Complications

    Science.gov (United States)

    Figueiredo, Pedro; Almeida, Nuno; Lopes, Sandra; Duque, Gabriela; Freire, Paulo; Lérias, Clotilde; Gouveia, Hermano; Sofia, Carlos

    2010-01-01

    Background. The aim of this work was to assess the value of capsule enteroscopy in the diagnosis of patients with suspected Crohn's Disease (CD). Methods. This was a retrospective study in a single tertiary care centre involving patients undergoing capsule enteroscopy for suspected CD. Patients taking nonsteroidal anti inflammatory drugs during the thirty preceding days or with a follow-up period of less than six months were excluded. Results. Seventy eight patients were included. The endoscopic findings included mucosal breaks in 50%, ulcerated stenosis in 5%, and villous atrophy in 4%. The diagnosis of CD was established in 31 patients. The sensitivity, specificity, positive and negative predictive value of the endoscopic findings were 93%, 80%, 77%, and 94%, respectively. Capsule retention occurred in four patients (5%). The presence of ulcerated stenosis was significantly more frequent in patients with positive inflammatory markers. The diagnostic yield of capsule enteroscopy in patients with negative ileoscopy was 56%, with a diagnostic acuity of 93%. Conclusions. Small bowel capsule endoscopy is a safe and valid technique for assessing patients with suspected CD. Capsule retention is more frequent in patients with positive inflammatory markers. Patients with negative ileoscopy and suspected CD should be submitted to capsule enteroscopy. PMID:20811612

  1. Small-Bowel Capsule Endoscopy in Patients with Suspected Crohn's Disease—Diagnostic Value and Complications

    Directory of Open Access Journals (Sweden)

    Pedro Figueiredo

    2010-01-01

    Full Text Available Background. The aim of this work was to assess the value of capsule enteroscopy in the diagnosis of patients with suspected Crohn's Disease (CD. Methods. This was a retrospective study in a single tertiary care centre involving patients undergoing capsule enteroscopy for suspected CD. Patients taking nonsteroidal anti inflammatory drugs during the thirty preceding days or with a follow-up period of less than six months were excluded. Results. Seventy eight patients were included. The endoscopic findings included mucosal breaks in 50%, ulcerated stenosis in 5%, and villous atrophy in 4%. The diagnosis of CD was established in 31 patients. The sensitivity, specificity, positive and negative predictive value of the endoscopic findings were 93%, 80%, 77%, and 94%, respectively. Capsule retention occurred in four patients (5%. The presence of ulcerated stenosis was significantly more frequent in patients with positive inflammatory markers. The diagnostic yield of capsule enteroscopy in patients with negative ileoscopy was 56%, with a diagnostic acuity of 93%. Conclusions. Small bowel capsule endoscopy is a safe and valid technique for assessing patients with suspected CD. Capsule retention is more frequent in patients with positive inflammatory markers. Patients with negative ileoscopy and suspected CD should be submitted to capsule enteroscopy.

  2. Orbits of the inner satellites of Neptune

    Science.gov (United States)

    Brozovic, Marina; Showalter, Mark R.; Jacobson, Robert Arthur; French, Robert S.; de Pater, Imke; Lissauer, Jack

    2018-04-01

    We report on the numerically integrated orbits of seven inner satellites of Neptune, including S/2004 N1, the last moon of Neptune to be discovered by the Hubble Space Telescope (HST). The dataset includes Voyager imaging data as well as the HST and Earth-based astrometric data. The observations span time period from 1989 to 2016. Our orbital model accounts for the equatorial bulge of Neptune, perturbations from the Sun and the planets, and perturbations from Triton. The initial orbital integration assumed that the satellites are massless, but the residuals improved significantly as the masses adjusted toward values that implied that the density of the satellites is in the realm of 1 g/cm3. We will discuss how the integrated orbits compare to the precessing ellipses fits, mean orbital elements, current orbital uncertainties, and the need for future observations.

  3. Using heteroclinic orbits to quantify topological entropy in fluid flows

    International Nuclear Information System (INIS)

    Sattari, Sulimon; Chen, Qianting; Mitchell, Kevin A.

    2016-01-01

    Topological approaches to mixing are important tools to understand chaotic fluid flows, ranging from oceanic transport to the design of micro-mixers. Typically, topological entropy, the exponential growth rate of material lines, is used to quantify topological mixing. Computing topological entropy from the direct stretching rate is computationally expensive and sheds little light on the source of the mixing. Earlier approaches emphasized that topological entropy could be viewed as generated by the braiding of virtual, or “ghost,” rods stirring the fluid in a periodic manner. Here, we demonstrate that topological entropy can also be viewed as generated by the braiding of ghost rods following heteroclinic orbits instead. We use the machinery of homotopic lobe dynamics, which extracts symbolic dynamics from finite-length pieces of stable and unstable manifolds attached to fixed points of the fluid flow. As an example, we focus on the topological entropy of a bounded, chaotic, two-dimensional, double-vortex cavity flow. Over a certain parameter range, the topological entropy is primarily due to the braiding of a period-three orbit. However, this orbit does not explain the topological entropy for parameter values where it does not exist, nor does it explain the excess of topological entropy for the entire range of its existence. We show that braiding by heteroclinic orbits provides an accurate computation of topological entropy when the period-three orbit does not exist, and that it provides an explanation for some of the excess topological entropy when the period-three orbit does exist. Furthermore, the computation of symbolic dynamics using heteroclinic orbits has been automated and can be used to compute topological entropy for a general 2D fluid flow.

  4. Cost-effectiveness of routine imaging of suspected appendicitis.

    Science.gov (United States)

    D'Souza, N; Marsden, M; Bottomley, S; Nagarajah, N; Scutt, F; Toh, S

    2018-01-01

    Introduction The misdiagnosis of appendicitis and consequent removal of a normal appendix occurs in one in five patients in the UK. On the contrary, in healthcare systems with routine cross-sectional imaging of suspected appendicitis, the negative appendicectomy rate is around 5%. If we could reduce the rate in the UK to similar numbers, would this be cost effective? This study aimed to calculate the financial impact of negative appendicectomy at the Queen Alexandra Hospital and to explore whether a policy of routine imaging of such patients could reduce hospital costs. Materials and methods We performed a retrospective analysis of all appendicectomies over a 1-year period at our institution. Data were extracted on outcomes including appendix histology, operative time and length of stay to calculate the negative appendicectomy rate and to analyse costs. Results A total of 531 patients over 5 years of age had an appendicectomy. The negative appendicectomy rate was 22% (115/531). The additional financial costs of negative appendicectomy to the hospital during this period were £270,861. Universal imaging of all patients with right iliac fossa pain that could result in a 5% negative appendicectomy rate would cost between £67,200 and £165,600 per year but could save £33,896 (magnetic resonance imaging), £105,896 (computed tomography) or £132,296 (ultrasound) depending on imaging modality used. Conclusions Negative appendicectomy is still too frequent and results in additional financial burden to the health service. Routine imaging of patients with suspected appendicitis would not only reduce the negative appendicectomy rate but could lead to cost savings and a better service for our patients.

  5. Interviewing strategically to elicit admissions from guilty suspects.

    Science.gov (United States)

    Tekin, Serra; Granhag, Pär Anders; Strömwall, Leif; Giolla, Erik Mac; Vrij, Aldert; Hartwig, Maria

    2015-06-01

    In this article we introduce a novel interviewing tactic to elicit admissions from guilty suspects. By influencing the suspects' perception of the amount of evidence the interviewer holds against them, we aimed to shift the suspects' counterinterrogation strategies from less to more forthcoming. The proposed tactic (SUE-Confrontation) is a development of the Strategic Use of Evidence (SUE) framework and aims to affect the suspects' perception by confronting them with statement-evidence inconsistencies. Participants (N = 90) were asked to perform several mock criminal tasks before being interviewed using 1 of 3 interview techniques: (a) SUE-Confrontation, (b) Early Disclosure of Evidence, or (c) No Disclosure of Evidence. As predicted, the SUE-Confrontation interview generated more statement-evidence inconsistencies from suspects than the Early Disclosure interview. Importantly, suspects in the SUE-Confrontation condition (vs. Early and No disclosure conditions) admitted more self-incriminating information and also perceived the interviewer to have had more information about the critical phase of the crime (the phase where the interviewer lacked evidence). The findings show the adaptability of the SUE-technique and how it may be used as a tool for eliciting admissions. (c) 2015 APA, all rights reserved).

  6. Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2004 - February 2006 : report

    Directory of Open Access Journals (Sweden)

    V. Naidoo

    2006-06-01

    Full Text Available The Veterinary Pharmacovigilance and Medicines Information Centre is responsible for the monitoring of veterinary adverse drug reactions in South Africa. An overview of reports of suspected adverse drug reactions received by the centre during the period March 2004 to February 2006 is presented. A total of 21 reports was received in the 2-year period, continuing the decline in the number of reports to a lower figure than in any previous year. This is surprising considering the legal obligation of the veterinary professionals to report all adverse drug reactions. Once again the majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most of the products implicated were stock remedies. Veterinarians predominantly administered these products.

  7. ON THE PULSATIONAL-ORBITAL-PERIOD RELATION OF ECLIPSING BINARIES WITH δ-SCT COMPONENTS

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X. B.; Luo, C. Q. [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Fu, J. N. [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)

    2013-11-01

    We have deduced a theoretical relation between the pulsation and orbital-periods of pulsating stars in close binaries based on their Roche lobe filling. It appears to be of a simple linear form, with the slope as a function of the pulsation constant, the mass ratio, and the filling factor for an individual system. Testing the data of 69 known eclipsing binaries containing δ-Sct-type components yields an empirical slope of 0.020 ± 0.006 for the P{sub pul}-P{sub orb} relation. We have further derived the upper limit of the P{sub pul}/P{sub orb} ratio for the δ-Sct stars in eclipsing binaries with a value of 0.09 ± 0.02. This value could serve as a criterion to distinguish whether or not a pulsator in an eclipsing binary pulsates in the p-mode. Applying the deduced P{sub pul}-P{sub orb} relation, we have computed the dominant pulsation constants for 37 δ-Sct stars in eclipsing systems with definite photometric solutions. These ranged between 0.008 and 0.033 days with a mean value of about 0.014 days, indicating that δ-Sct stars in eclipsing binaries mostly pulsate in the fourth or fifth overtones.

  8. A neonate with intestinal volvulus without malrotation exhibiting early jaundice with a suspected fetal onset.

    Science.gov (United States)

    Hara, Kaori; Kinoshita, Mari; Kin, Takane; Arimitsu, Takeshi; Matsuzaki, Yohei; Ikeda, Kazushige; Tomita, Hiroshi; Fujino, Akihiro; Kuroda, Tatsuo

    2015-01-01

    Intestinal volvulus without malrotation is a rare disease that causes volvulus of the small intestine despite normal intestinal rotation and fixation. We encountered a neonate with this disease who developed early jaundice and was suspected to have a fetal onset. This patient was characterized by early jaundice complicating intestinal volvulus without malrotation and is considered to have exhibited reduced fetal movement and early jaundice as a result of volvulus, necrosis, and hemorrhage of the small intestine in the fetal period. If abdominal distention accompanied by early jaundice is noted in a neonate, intestinal volvulus without malrotation and associated intraabdominal hemorrhage should be suspected and promptly treated.

  9. Technical-economic feasibility of orbiting sunlight reflectors

    Science.gov (United States)

    Alferov, Z.; Minin, V.

    1986-02-01

    The use of deflectors in orbit as a means of providing artificial illumination is examined. Considerations of technical and economic feasibility are addressed. Three main areas of application are distinguished: reflecting sunlight onto the surface of the Earth; concentration of the flow of solar energy on an orbiting receiver; and retransmission of optical radiation. The advantages of the artificial Earth illumination application of the orbiting reflector scheme in terms of energy savings in lighting cities, and additional daylight time for critical periods of farming operations are discussed.

  10. WIYN Open Cluster Study: Binary Orbits and Tidal Circularization in NGC 6819

    Science.gov (United States)

    Morscher, Meagan B.; Mathieu, R. D.; Kaeppler, S.; Hole, K. T.; Meibom, S.

    2006-12-01

    We are conducting a comprehensive stellar radial-velocity survey in NGC 6819, a rich, intermediate age ( 2.4 Gyr) open cluster with [Fe/H] -0.05. As of October 2006, we have obtained 7065 radial-velocity measurements of 1409 stars using the WIYN Hydra Multi-Object Spectrograph, with typical velocity measurement precisions of 0.4 km/s. Using an E/I criterion of 3, we have identified 282 velocity variables. In the past year we have expanded the number of final orbital solutions by 45 to a total of more than 80 solutions. In coeval stellar populations, circular binaries tend to have the shortest orbital periods, while longer period binaries show a distribution of non-zero eccentricities. The circularization of the shortest period orbits is the result of an exchange of stellar and orbital angular momentum due to tidal interactions. We defined a population’s tidal circularization period as the longest orbital period at which a binary of typical initial eccentricity has become circularized (e.g., has evolved to an eccentricity e = 0.01) over the lifetime of the cluster (Meibom & Mathieu, 2005, ApJ, 620, 970). We are studying the trend of increasing tidal circularization periods with population age. Preliminary results in NGC 6819 indicate a tidal circularization period of 7.5 days, which is consistent with this overall trend. We will recalculate the tidal circularization period in order to include the latest sample of orbital solutions. This comprehensive survey also allows us to investigate the relative spatial distributions of spectroscopic binaries and other constant-velocity cluster members of similar mass. We find the spectroscopic binaries to be more centrally concentrated at a statistically significant level, which we attribute to energy equipartition processes. MM was supported by REU NSF grant AST-0453442. RDM, SK, KTH, and SM were supported by NSF grant AST-0406615.

  11. Three Temperate Neptunes Orbiting Nearby Stars

    Science.gov (United States)

    Fulton, Benjamin J.; Howard, Andrew W.; Weiss, Lauren M.; Sinukoff, Evan; Petigura, Erik A.; Isaacson, Howard; Hirsch, Lea; Marcy, Geoffrey W.; Henry, Gregory W.; Grunblatt, Samuel K.; Huber, Daniel; von Braun, Kaspar; Boyajian, Tabetha S.; Kane, Stephen R.; Wittrock, Justin; Horch, Elliott P.; Ciardi, David R.; Howell, Steve B.; Wright, Jason T.; Ford, Eric B.

    2016-10-01

    We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4 {M}\\oplus , a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6 {M}\\oplus and orbits interior to the previously known Jovian mass planet orbiting at 2.1 au. HD 164922 c has a semimajor axis of 0.34 au and an equilibrium temperature of 418 K. HD 143761 c orbits with a semimajor axis of 0.44 au, has a minimum mass of 25 ± 2 {M}\\oplus , and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of Hawai‘I, the University of California, and NASA.

  12. Secular Orbit and Spin Variations of Asteroid (16) Psyche

    Science.gov (United States)

    Bills, B. G.; Park, R. S.; Scott, B.

    2016-12-01

    The obliquity, or angular separation between spin and orbit poles, of asteroid (16) Psyche is currently 95 degrees. We are interested in knowing how much that angular separation varies, on time scales of 104 to 106 years. To answer that question, we have done several related analyses. On short time scales, the orbital element variations of Psyche are dominated by perturbations from Jupiter. Jupiter's dominance has two basic causes: first is the large mass and relatively close position of Jupiter, and second is a 19:8 mean motion resonance. Jupiter completes 8 orbits in 94.9009 years, while Psyche takes 94.9107 years to complete 19 orbits. As a result of this, all of the orbital elements of Psyche exhibit significant periodic variations, with a 94.9 year period dominating. There are also significant variations at the synodic period, which is 8.628 years, or 1/11 of the resonant period. Over a 1000 year time span, centered on the present, the eccentricity varies from 0.133 to 0.140, and the inclination varies from 2.961 to 3.229 degrees. On longer time scales, the orbital elements of Psyche vary considerably more than that, due to secular perturbations from the planets. The secular variations are modeled as the response of interacting mass rings, rather than point masses. Again, Jupiter is the main perturbing influence on Psyche. The eccentricity and inclination both oscillate, with dominant periods of 18.667 kyr. The range of values seen over a million year time span, is 0.057 to 0.147 for eccentricity, and 0.384 to 4.777 degrees for inclination. Using a recent shape model, and assumption of uniform density, to constrain relevant moments of inertia, we estimate the spin pole precession rate parameter to be 8.53 arcsec/year. The current spin pole is at ecliptic {lon, lat} = { 32, -7} deg, whereas the orbit pole is at {lon, lat} = {60.47, 86.91} deg. The current obliquity is thus 94.3 degree. Using nominal values of the input parameters, the recovered spin pole

  13. Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes

    Science.gov (United States)

    Sośnica, Krzysztof; Prange, Lars; Kaźmierski, Kamil; Bury, Grzegorz; Drożdżewski, Mateusz; Zajdel, Radosław; Hadas, Tomasz

    2018-02-01

    The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR-GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0-2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal -44.9, -35.0, and -22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear

  14. Analysis of orbit determination from Earth-based tracking for relay satellites in a perturbed areostationary orbit

    Science.gov (United States)

    Romero, P.; Pablos, B.; Barderas, G.

    2017-07-01

    Areostationary satellites are considered a high interest group of satellites to satisfy the telecommunications needs of the foreseen missions to Mars. An areostationary satellite, in an areoequatorial circular orbit with a period of 1 Martian sidereal day, would orbit Mars remaining at a fixed location over the Martian surface, analogous to a geostationary satellite around the Earth. This work addresses an analysis of the perturbed orbital motion of an areostationary satellite as well as a preliminary analysis of the aerostationary orbit estimation accuracy based on Earth tracking observations. First, the models for the perturbations due to the Mars gravitational field, the gravitational attraction of the Sun and the Martian moons, Phobos and Deimos, and solar radiation pressure are described. Then, the observability from Earth including possible occultations by Mars of an areostationary satellite in a perturbed areosynchronous motion is analyzed. The results show that continuous Earth-based tracking is achievable using observations from the three NASA Deep Space Network Complexes in Madrid, Goldstone and Canberra in an occultation-free scenario. Finally, an analysis of the orbit determination accuracy is addressed considering several scenarios including discontinuous tracking schedules for different epochs and different areoestationary satellites. Simulations also allow to quantify the aerostationary orbit estimation accuracy for various tracking series durations and observed orbit arc-lengths.

  15. Astrometric detectability of systems with unseen companions: effects of the Earth orbital motion

    Science.gov (United States)

    Butkevich, Alexey G.

    2018-06-01

    The astrometric detection of an unseen companion is based on an analysis of the apparent motion of its host star around the system's barycentre. Systems with an orbital period close to 1 yr may escape detection if the orbital motion of their host stars is observationally indistinguishable from the effects of parallax. Additionally, an astrometric solution may produce a biased parallax estimation for such systems. We examine the effects of the orbital motion of the Earth on astrometric detectability in terms of a correlation between the Earth's orbital position and the position of the star relative to its system barycentre. The χ2 statistic for parallax estimation is calculated analytically, leading to expressions that relate the decrease in detectability and accompanying parallax bias to the position correlation function. The impact of the Earth's motion critically depends on the exoplanet's orbital period, diminishing rapidly as the period deviates from 1 yr. Selection effects against 1-yr-period systems is, therefore, expected. Statistical estimation shows that the corresponding loss of sensitivity results in a typical 10 per cent increase in the detection threshold. Consideration of eccentric orbits shows that the Earth's motion has no effect on detectability for e≳ 0.5. The dependence of the detectability on other parameters, such as orbital phases and inclination of the orbital plane to the ecliptic, are smooth and monotonic because they are described by simple trigonometric functions.

  16. M2K. II. A TRIPLE-PLANET SYSTEM ORBITING HIP 57274

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Debra A.; Giguere, Matthew J.; Moriarty, John; Brewer, John; Spronck, Julien F. P.; Schwab, Christian; Szymkowiak, Andrew [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Gaidos, Eric [Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822 (United States); Howard, Andrew W.; Marcy, Geoffrey W. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Johnson, John A. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Wright, Jason T. [Center for Exoplanets and Habitable Worlds, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16803 (United States); Valenti, Jeff A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Piskunov, Nikolai [Department of Astronomy and Space Physics, Uppsala University, Box 515, 751 20 Uppsala (Sweden); Clubb, Kelsey I.; Isaacson, Howard [Pufendorf Institute for Advanced Studies, Lund University, Lund (Sweden); Apps, Kevin [75B Cheyne Walk, Surrey RH6 7LR (United Kingdom); Lepine, Sebastien [American Museum of Natural History, New York, NY 10023 (United States); Mann, Andrew, E-mail: debra.fischer@yale.edu [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

    2012-01-20

    Doppler observations from Keck Observatory have revealed a triple-planet system orbiting the nearby K4V star, HIP 57274. The inner planet, HIP 57274b, is a super-Earth with Msin i = 11.6 M{sub Circled-Plus} (0.036 M{sub Jup}), an orbital period of 8.135 {+-} 0.004 days, and slightly eccentric orbit e = 0.19 {+-} 0.1. We calculate a transit probability of 6.5% for the inner planet. The second planet has Msin i = 0.4 M{sub Jup} with an orbital period of 32.0 {+-} 0.02 days in a nearly circular orbit (e = 0.05 {+-} 0.03). The third planet has Msin i = 0.53 M{sub Jup} with an orbital period of 432 {+-} 8 days (1.18 years) and an eccentricity e = 0.23 {+-} 0.03. This discovery adds to the number of super-Earth mass planets with M sin i < 12 M{sub Circled-Plus} that have been detected with Doppler surveys. We find that 56% {+-} 18% of super-Earths are members of multi-planet systems. This is certainly a lower limit because of observational detectability limits, yet significantly higher than the fraction of Jupiter mass exoplanets, 20% {+-} 8%, that are members of Doppler-detected, multi-planet systems.

  17. M2K. II. A TRIPLE-PLANET SYSTEM ORBITING HIP 57274

    International Nuclear Information System (INIS)

    Fischer, Debra A.; Giguere, Matthew J.; Moriarty, John; Brewer, John; Spronck, Julien F. P.; Schwab, Christian; Szymkowiak, Andrew; Gaidos, Eric; Howard, Andrew W.; Marcy, Geoffrey W.; Johnson, John A.; Wright, Jason T.; Valenti, Jeff A.; Piskunov, Nikolai; Clubb, Kelsey I.; Isaacson, Howard; Apps, Kevin; Lepine, Sebastien; Mann, Andrew

    2012-01-01

    Doppler observations from Keck Observatory have revealed a triple-planet system orbiting the nearby K4V star, HIP 57274. The inner planet, HIP 57274b, is a super-Earth with Msin i = 11.6 M ⊕ (0.036 M Jup ), an orbital period of 8.135 ± 0.004 days, and slightly eccentric orbit e = 0.19 ± 0.1. We calculate a transit probability of 6.5% for the inner planet. The second planet has Msin i = 0.4 M Jup with an orbital period of 32.0 ± 0.02 days in a nearly circular orbit (e = 0.05 ± 0.03). The third planet has Msin i = 0.53 M Jup with an orbital period of 432 ± 8 days (1.18 years) and an eccentricity e = 0.23 ± 0.03. This discovery adds to the number of super-Earth mass planets with M sin i ⊕ that have been detected with Doppler surveys. We find that 56% ± 18% of super-Earths are members of multi-planet systems. This is certainly a lower limit because of observational detectability limits, yet significantly higher than the fraction of Jupiter mass exoplanets, 20% ± 8%, that are members of Doppler-detected, multi-planet systems.

  18. Shells, orbit bifurcations, and symmetry restorations in Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Magner, A. G., E-mail: magner@kinr.kiev.ua; Koliesnik, M. V. [NASU, Institute for Nuclear Research (Ukraine); Arita, K. [Nagoya Institute of Technology, Department of Physics (Japan)

    2016-11-15

    The periodic-orbit theory based on the improved stationary-phase method within the phase-space path integral approach is presented for the semiclassical description of the nuclear shell structure, concerning themain topics of the fruitful activity ofV.G. Soloviev. We apply this theory to study bifurcations and symmetry breaking phenomena in a radial power-law potential which is close to the realistic Woods–Saxon one up to about the Fermi energy. Using the realistic parametrization of nuclear shapes we explain the origin of the double-humped fission barrier and the asymmetry in the fission isomer shapes by the bifurcations of periodic orbits. The semiclassical origin of the oblate–prolate shape asymmetry and tetrahedral shapes is also suggested within the improved periodic-orbit approach. The enhancement of shell structures at some surface diffuseness and deformation parameters of such shapes are explained by existence of the simple local bifurcations and new non-local bridge-orbit bifurcations in integrable and partially integrable Fermi-systems. We obtained good agreement between the semiclassical and quantum shell-structure components of the level density and energy for several surface diffuseness and deformation parameters of the potentials, including their symmetry breaking and bifurcation values.

  19. Book Review: Placing the Suspect behind the Keyboard: Using Digital Forensics and Investigative Techniques to Identify Cybercrime Suspects

    Directory of Open Access Journals (Sweden)

    Thomas Nash

    2013-06-01

    Full Text Available Shavers, B. (2013. Placing the Suspect behind the Keyboard: Using Digital Forensics and Investigative Techniques to Identify Cybercrime Suspects. Waltham, MA: Elsevier, 290 pages, ISBN-978-1-59749-985-9, US$51.56. Includes bibliographical references and index.Reviewed by Detective Corporal Thomas Nash (tnash@bpdvt.org, Burlington Vermont Police Department, Internet Crime against Children Task Force. Adjunct Instructor, Champlain College, Burlington VT.In this must read for any aspiring novice cybercrime investigator as well as the seasoned professional computer guru alike, Brett Shaver takes the reader into the ever changing and dynamic world of Cybercrime investigation.  Shaver, an experienced criminal investigator, lays out the details and intricacies of a computer related crime investigation in a clear and concise manner in his new easy to read publication, Placing the Suspect behind the Keyboard. Using Digital Forensics and Investigative techniques to Identify Cybercrime Suspects. Shaver takes the reader from start to finish through each step of the investigative process in well organized and easy to follow sections, with real case file examples to reach the ultimate goal of any investigation: identifying the suspect and proving their guilt in the crime. Do not be fooled by the title. This excellent, easily accessible reference is beneficial to both criminal as well as civil investigations and should be in every investigator’s library regardless of their respective criminal or civil investigative responsibilities.(see PDF for full review

  20. On the atmospheric drag in orbit determination for low Earth orbit

    Science.gov (United States)

    Tang, Jingshi; Liu, Lin; Miao, Manqian

    2012-07-01

    The atmosphere model is always a major limitation for low Earth orbit (LEO) in orbit prediction and determination. The accelerometer can work around the non-gravitational perturbations in orbit determination, but it helps little to improve the atmosphere model or to predict the orbit. For certain satellites, there may be some specific software to handle the orbit problem. This solution can improve the orbit accuracy for both prediction and determination, yet it always contains empirical terms and is exclusive for certain satellites. This report introduces a simple way to handle the atmosphere drag for LEO, which does not depend on instantaneous atmosphere conditions and improves accuracy of predicted orbit. This approach, which is based on mean atmospheric density, is supported by two reasons. One is that although instantaneous atmospheric density is very complicated with time and height, the major pattern is determined by the exponential variation caused by hydrostatic equilibrium and periodic variation caused by solar radiation. The mean density can include the major variations while neglect other minor details. The other reason is that the predicted orbit is mathematically the result from integral and the really determinant factor is the mean density instead of instantaneous density for every time and spot. Using the mean atmospheric density, which is mainly determined by F10.7 solar flux and geomagnetic index, can be combined into an overall parameter B^{*} = C_{D}(S/m)ρ_{p_{0}}. The combined parameter contains several less accurate parameters and can be corrected during orbit determination. This approach has been confirmed in various LEO computations and an example is given below using Tiangong-1 spacecraft. Precise orbit determination (POD) is done using one-day GPS positioning data without any accurate a-priori knowledge on spacecraft or atmosphere conditions. Using the corrected initial state vector of the spacecraft and the parameter B^* from POD, the

  1. Minimum period and the gap in periods of Cataclysmic binaries

    International Nuclear Information System (INIS)

    Paczynski, B.; Sienkiewicz, R.

    1983-01-01

    The 81 minute cutoff to the orbital periods of hydrogen-rich cataclysmic binaries is consistent with evolution of those systems being dominated by angular momentum losses due to gravitational radiation. Unfortunately, many uncertainties, mainly poorly known atmospheric opacities below 2000 K, make is physically impossible to verify the quadrupole formula for gravitational radiation by using the observed cutoff at 81 minutes. The upper boundary of the gap in orbital periods observed at about 3 hours is almost certainly due to enhanced angular momentum losses from cataclysmic binaries which have longer periods. The physical mechanism of those losses is not identified, but a possible importance of stellar winds is pointed out. The lower boundary of the gap may be explained with the oldest cataclysmic binaries, whose periods evolved past the minimum at 81 minutes and reached the value of 2 hours within about 12 x 10 9 years after the binary had formed. Those binaries should have secondary components of only 0.02 solar masses, and their periods could be used to estimate ages of the oldest cataclysmic stars, and presumably the age of Galaxy. An alternative explanation for the gap requires that binaries should be detached while crossing the gap. A possible mechanism for this phenomenon is discussed. It requires the secondary components to be about 0.2 solar masses in the binaries just below the gap

  2. Uncertainty Requirement Analysis for the Orbit, Attitude, and Burn Performance of the 1st Lunar Orbit Insertion Maneuver

    Directory of Open Access Journals (Sweden)

    Young-Joo Song

    2016-12-01

    Full Text Available In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the 1st lunar orbit insertion (LOI maneuver of the Korea Pathfinder Lunar Orbiter (KPLO mission. During the early design phase of the system, associate analysis is an essential design factor as the 1st LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the 1st LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the 1st elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground

  3. Semiclassical description of resonant tunnel effect: bifurcations and periodic orbits in the resonant current

    International Nuclear Information System (INIS)

    Rouben, D.C.

    1997-01-01

    A semiclassical method for resonant tunneling in a quantum well in the presence of a magnetic field tilted with regard to an electric field is developed. In particular a semiclassical formula is derived for the total current of electrons after the second barrier of the quantum well. The contribution of the stable and unstable orbits is studied. It appears that the parameters which describe the classical chaos in the quantum well have an important effect on the tunneling current. A numerical experiment is led, the contributions to the current of some particular orbits are evaluated and the results are compared with those given by the quantum theory. (A.C.)

  4. How useful is gastroesophageal reflux scintigraphy in suspected childhood aspiration?

    International Nuclear Information System (INIS)

    Fawcett, H.D.; Adams, J.C.; Hayden, C.K.; Swischuk, L.E.

    1988-01-01

    It has been suggested that gastroesophageal reflux scintigraphy might be useful in assisting one in determining therapy for patients suspected of aspirating or becoming apneic secondary to gastroesophageal reflux. This, however, has not been our experience and in reviewing 23 patients with recurrent pneumonia and/or apnea who had gastroesophageal reflux scintigraphy, we were able to detect aspiration in only one. This was especially significant since 13 (59%) of these patients had demonstrable reflux, and of these, eight were treated successfully for suspected aspiration even though none was demonstrated isotopically. To be sure, the demonstration of pulmonary aspiration with gastroesophageal reflux scintigraphy had little influence on patient selection and response to therapy. For this reason we feel there is little justification in depending on the GRS for the specific purpose of trying to document pulmonary aspiration in infants and children who are refluxing. One of the more serious complications of gastroesophageal (GE) reflux is aspiration leading to recurrent pulmonary infections and/or apnea. However, it always has been difficult to demonstrate actual aspiration into the lungs, and to be sure, barium studies of the upper GI tract seldom reveal this complication. Recently, however, considerable interest has been generated in gastroesophageal scintigraphy (GRS) as a possible means of documenting such aspiration. Rationale for this stems from the fact that suspected patients can be studied over a longer period of time and in addition, delayed and overnight images can be obtained. However, our experience does not support GRS as being an adequate method for demonstrating aspiration. (orig.)

  5. How useful is gastroesophageal reflux scintigraphy in suspected childhood aspiration

    Energy Technology Data Exchange (ETDEWEB)

    Fawcett, H.D.; Adams, J.C.; Hayden, C.K.; Swischuk, L.E.

    1988-05-01

    It has been suggested that gastroesophageal reflux scintigraphy might be useful in assisting one in determining therapy for patients suspected of aspirating or becoming apneic secondary to gastroesophageal reflux. This, however, has not been our experience and in reviewing 23 patients with recurrent pneumonia and/or apnea who had gastroesophageal reflux scintigraphy, we were able to detect aspiration in only one. This was especially significant since 13 (59%) of these patients had demonstrable reflux, and of these, eight were treated successfully for suspected aspiration even though none was demonstrated isotopically. To be sure, the demonstration of pulmonary aspiration with gastroesophageal reflux scintigraphy had little influence on patient selection and response to therapy. For this reason we feel there is little justification in depending on the GRS for the specific purpose of trying to document pulmonary aspiration in infants and children who are refluxing. One of the more serious complications of gastroesophageal (GE) reflux is aspiration leading to recurrent pulmonary infections and/or apnea. However, it always has been difficult to demonstrate actual aspiration into the lungs, and to be sure, barium studies of the upper GI tract seldom reveal this complication. Recently, however, considerable interest has been generated in gastroesophageal scintigraphy (GRS) as a possible means of documenting such aspiration. Rationale for this stems from the fact that suspected patients can be studied over a longer period of time and in addition, delayed and overnight images can be obtained. However, our experience does not support GRS as being an adequate method for demonstrating aspiration.

  6. Radiologic evaluation of orbital index among Ghanaians using CT scan

    OpenAIRE

    Botwe, Benard Ohene; Sule, Derick Seyram; Ismael, Abdul Mumin

    2017-01-01

    Background Orbital index (OI) expresses the proportion of the orbital height to the orbital width and varies with race, regions within the same race and periods in evolution. This index is useful in forensic medicine, anthropology and surgery. However, the average OI among Ghanaian adults was unknown. Aim The aim of this study was to determine the orbital index of adult Ghanaians and classify them under one of the three predetermined groups. Method The study design was a retrospective cross-s...

  7. Periodic orbits from Δ-modulation of stable linear systems

    OpenAIRE

    Xia, X.; Zinober, A.

    2004-01-01

    The �-modulated control of a single input, discrete time, linear stable system is investigated. The modulation direction is given by cTx where c �Rn/{0} is a given, otherwise arbitrary, vector. We obtain necessary and sufficient conditions for the existence of periodic points of a finite order. Some concrete results about the existence of a certain order of periodic points are also derived. We also study the relationship between certain polyhedra and the periodicity of the �-modulated orb...

  8. The TWA 3 Young Triple System: Orbits, Disks, Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, Kendra [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Prato, L.; Avilez, I.; Wasserman, L. H.; Levine, S. E.; Bosh, A. S. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Schaefer, G. H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Ruíz-Rodríguez, D. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bonanos, Alceste Z. [IAASARS, National Observatory of Athens, 15236 Penteli (Greece); Guenther, E. W. [Thüringer Landessternwarte Tautenburg, D-07778 Tautenburg (Germany); Neuhäuser, R. [Astrophysikalisches Institut und Universitäts-Sternwarte, FSU Jena, Schillergäßchen 2-3, D-07745 Jena (Germany); Morzinski, Katie M.; Close, Laird; Hinz, Phil; Males, Jared R. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Bailey, Vanessa, E-mail: kkellogg@uwo.ca, E-mail: lprato@lowell.edu [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA, 94305 (United States)

    2017-08-01

    We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit, as well as for the wide TWA 3A–B orbit. TWA 3 is a hierarchical triple located at 34 pc in the ∼10 Myr old TW Hya association. The wide component separation is 1.″55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy that angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a reanalysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is ∼35 days, the eccentricity is ∼0.63, and the mass ratio is ∼0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least ∼30°. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.

  9. NICER Discovers the Ultracompact Orbit of the Accreting Millisecond Pulsar IGR J17062–6143

    DEFF Research Database (Denmark)

    Strohmayer, T. E.; Arzoumanian, Z.; Bogdanov, S.

    2018-01-01

    We present results of recent Neutron Star Interior Composition Explorer (NICER) observations of the accreting millisecond X-ray pulsar (AMXP) IGR J17062−6143 that show that it resides in a circular, ultracompact binary with a 38-minute orbital period. NICER observed the source for ≈26 ks over a 5...... of the neutron star. A coherent search for the orbital solution using the Z2 method finds a best-fitting circular orbit with a period of 2278.21 s (37.97 minutes), a projected semimajor axis of 0.00390 lt-s, and a barycentric pulsar frequency of 163.6561105 Hz. This is currently the shortest known orbital period...

  10. Three Super-Earths Orbiting HD 7924

    Science.gov (United States)

    Fulton, Benjamin J.; Weiss, Lauren M.; Sinukoff, Evan; Isaacson, Howard; Howard, Andrew W.; Marcy, Geoffrey W.; Henry, Gregory W.; Holden, Bradford P.; Kibrick, Robert I.

    2015-06-01

    We report the discovery of two super-Earth-mass planets orbiting the nearby K0.5 dwarf HD 7924, which was previously known to host one small planet. The new companions have masses of 7.9 and 6.4 {{M}\\oplus }, and orbital periods of 15.3 and 24.5 days. We perform a joint analysis of high-precision radial velocity data from Keck/HIRES and the new Automated Planet Finder Telescope (APF) to robustly detect three total planets in the system. We refine the ephemeris of the previously known planet using 5 yr of new Keck data and high-cadence observations over the last 1.3 yr with the APF. With this new ephemeris, we show that a previous transit search for the inner-most planet would have covered 70% of the predicted ingress or egress times. Photometric data collected over the last eight years using the Automated Photometric Telescope shows no evidence for transits of any of the planets, which would be detectable if the planets transit and their compositions are hydrogen-dominated. We detect a long-period signal that we interpret as the stellar magnetic activity cycle since it is strongly correlated with the Ca ii H and K activity index. We also detect two additional short-period signals that we attribute to rotationally modulated starspots and a one-month alias. The high-cadence APF data help to distinguish between the true orbital periods and aliases caused by the window function of the Keck data. The planets orbiting HD 7924 are a local example of the compact, multi-planet systems that the Kepler Mission found in great abundance. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of Hawai‘i, the University of California, and NASA.

  11. Value of noncontrast spiral CT for suspected acute appendicitis

    International Nuclear Information System (INIS)

    Choi, Pil Yeob; Lee, Sang Wook; Kwon, Jae Soo; Sung, Young Soon; Rho, Myoung Ho; Chang, Jeong A.

    1998-01-01

    To assess the diagnostic accuracy and clinical efficacy of noncontrast spiral CT in patients with suspected acute appendicitis. Over a six-month period, 100 patients with suspected acute appendicitis were prospectively evaluated with noncontrast spiral CT. All scans were obtained from the lower body of L3 to the symphysis pubis, with 5mm or 10mm collimation and pitch of 1 or 1.5, and without intravenous or oral contrast material. Diagnosis was established by means of surgical or clinical follow-up. Prospective diagnosis based on CT findings was compared with surgical results and clinical follow-up. Acute appendicitis was confirmed in 47 of 100 patients. On the basis of the Ct findings, SI patients were prospectively interpreted as positive for appendicitis, but in six the diagnosis was false-positive. Two of the 47 with acute appendicitis were prospectively interpreted as normal. The preoperative diagnosis of acute appendicitis was, thus, 45 true-positive, 47 true-negative, six false-positive and two false-negative yielding a sensitivity of 96%, a specificity of 89%, an accuracy of 92%, a positive predictive value of 88%, and a negative predictive value of 96%. Using CT, an alternative diagnosis was established in 14 patients. Noncontrast spiral CT is a useful technique for diagnosing acute appendicitis. =20

  12. Orbit Feedback Operation with RCBX (MD 1209)

    CERN Document Server

    Wenninger, Jorg; Nisbet, David; Ponce, Laurette; Louro Alves, Diogo Miguel; CERN. Geneva. ATS Department

    2017-01-01

    The LHC Orbit Feedback (OFB) is able to drive any orbit corrector circuit (COD) to steer the LHC orbit. But during the first feedback tests in 2010, all attempts to use the common triplet orbit correctors (MCBX) failed because the QPS system installed to protect those magnets triggered power aborts as soon as the OFB steered the beam with those CODs. The reason was most likely the violation of the RCBX circuit acceleration limits. For this reason the MCBX orbit correctors were never driven by the OFB in regular operation. Although the performance of the OFB is generally excellent, the quality of the beam steering around IRs could be improved if the OFB could correct the orbit with the MCBX to counteract locally triplet quadrupole movements. The aim of this MD was to make a new attempt to use the MCBX in the OFB. The test was successful at injection (no circuit trip) and failed during the ramp (QPS power abort). The PC voltages and QPS Ures signals revealed the presence of voltage spikes with a period of 10~s...

  13. 48 CFR 403.303 - Reporting suspected antitrust violations.

    Science.gov (United States)

    2010-10-01

    ... Antitrust Violations 403.303 Reporting suspected antitrust violations. Contracting officers shall report the circumstances of suspected violations of antitrust laws to the Office of Inspector General in accordance with... antitrust violations. 403.303 Section 403.303 Federal Acquisition Regulations System DEPARTMENT OF...

  14. Post-aerocapture orbit selection and maintenance for the Aerofast mission to Mars

    Science.gov (United States)

    Pontani, Mauro; Teofilatto, Paolo

    2012-10-01

    Aerofast is the abbreviation of “aerocapture for future space transportation” and represents a project aimed at developing aerocapture techniques with regard to an interplanetary mission to Mars, in the context of the 7th Framework Program, with the financial support of the European Union. This paper describes the fundamental characteristics of the operational orbit after aerocapture for the mission of interest, as well as the related maintenance strategy. The final orbit selection depends on the desired lighting conditions, maximum revisit time of specific target regions, and feasibility of the orbit maintenance strategy. A sunsynchronous, frozen, repeating-ground-track orbit is chosen. First, the period of repetition is such that adjacent ascending node crossings (over the Mars surface) have a separation compatible with the swath of the optical payload. Secondly, the sunsynchronism condition ensures that a given latitude is periodically visited at the same local time, which condition is essential for comparing images of the same region at different epochs. Lastly, the fulfillment of the frozen condition guarantees improved orbit stability with respect to perturbations due to the zonal harmonics of Mars gravitational field. These three fundamental features of the operational orbit lead to determining its mean orbital elements. The evaluation of short and long period effects (e.g., those due to the sectorial harmonics of the gravitational field or to the aerodynamic drag) requires the determination of the osculating orbital elements at an initial reference time. This research describes a simple and accurate approach that leads to numerically determining these initial values, without employing complicated analytical developments. Numerical simulations demonstrate the long-period stability of the orbit when a significant number of harmonics of the gravitational field are taken into account. However, aerodynamic drag produces a relatively slow orbital decay at the

  15. Orbital Resonances in the Vinti Solution

    Science.gov (United States)

    Zurita, L. D.

    As space becomes more congested, contested, and competitive, high-accuracy orbital predictions become critical for space operations. Current orbit propagators use the two-body solution with perturbations added, which have significant error growth when numerically integrated for long time periods. The Vinti Solution is a more accurate model than the two-body problem because it also accounts for the equatorial bulge of the Earth. Unfortunately, the Vinti solution contains small divisors near orbital resonances in the perturbative terms of the Hamiltonian, which lead to inaccurate orbital predictions. One approach to avoid the small divisors is to apply transformation theory, which is presented in this research. The methodology of this research is to identify the perturbative terms of the Vinti Solution, perform a coordinate transformation, and derive the new equations of motion for the Vinti system near orbital resonances. An analysis of these equations of motion offers insight into the dynamics found near orbital resonances. The analysis in this research focuses on the 2:1 resonance, which includes the Global Positioning System. The phase portrait of a nominal Global Positioning System satellite orbit is found to contain a libration region and a chaotic region. Further analysis shows that the dynamics of the 2:1 resonance affects orbits with semi-major axes ranging from -5.0 to +5.4 kilometers from an exactly 2:1 resonant orbit. Truth orbits of seven Global Positioning System satellites are produced for 10 years. Two of the satellites are found to be outside of the resonance region and three are found to be influenced by the libration dynamics of the resonance. The final satellite is found to be influenced by the chaotic dynamics of the resonance. This research provides a method of avoiding the small divisors found in the perturbative terms of the Vinti Solution near orbital resonances.

  16. Flap tear of rectus muscles: an underlying cause of strabismus after orbital trauma.

    Science.gov (United States)

    Ludwig, Irene H; Brown, Mark S

    2002-11-01

    To present an avulsion injury of the rectus muscle after orbital trauma, usually the inferior rectus, and detail its diagnosis and operative repair. Forty-three patients underwent repair of flap tears of 62 rectus muscles. During surgery, we found the muscle abnormality was often subtle, with narrowing or thinning of the remaining attached global layer of muscle. The detached flap of external (orbital) muscle was found embedded in surrounding orbital fat and connective tissue. Retrieval and repair were performed in each case. The causes of orbital trauma were as follows: orbital fractures (15 patients), blunt trauma with no fracture (11 patients), suspected trauma but did not undergo computerized tomographic scan (12 patients), and status after retinal detachment repair (5 patients). Of note, 15 of the 43 patients (35%) underwent repair of the flap tear alone, without any additional orbital or strabismus surgery. Diagnostically, the predominant motility defect in 45 muscles was limitation toward the field of action of the muscle, presumably as a result of a tether created by the torn flap; these tethers simulated muscle palsy. Seventeen muscles were restricted away from their field of action, simulating entrapment. The direction taken by the flap during healing determined the resultant strabismus pattern. All patients with gaze limitation toward an orbital fracture had flap tears. The worst results after flap tear repair were seen in patients (1) who had undergone orbital fracture repair before presentation, (2) who had undergone previous attempts at strabismus repair, and (3) who had the longest intervals between the precipitating event and the repair. The best results were obtained in patients who underwent simultaneous fracture and strabismus repair or early strabismus repair alone. Avulsion-type flap tears of the extraocular muscles are a common cause of posttraumatic strabismus. Early repair produces the best results, but improvement is possible despite long

  17. Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2001 - February 2002 : report

    Directory of Open Access Journals (Sweden)

    V. Naidoo

    2002-07-01

    Full Text Available An overview of reports of suspected adverse drug reactions received by the Veterinary Pharmacovigilance and Medicines Information Centre during the period March 2001 to February 2002 is given. A total of 77 reports were received. The majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most products implicated in the reports were Stock Remedies. The products were predominantly administered either by veterinarians or trained paraveterinary professionals. Although the majority of reports were received from veterinary pharmaceutical companies, the proportion of reports received directly from veterinarians increased compared with previous years.

  18. Cytogenetic dosimetry in suspected cases of ionizing radiation occupational exposure

    International Nuclear Information System (INIS)

    Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S.; Silva, Francisco Cesar A. da

    2001-01-01

    Cytogenetic dosimetry is very useful in routine as well as in serious accident situations in which exposed individuals do not wear physical dosimeters. Since 1984, the technique of cytogenetic dosimetry has been used as a routine in our laboratory at IRD/CNEN to complement the data of physical dosimetry. In the period from 1984 to 2000, 138 cases of occupational overexposure of individual dosimeters were investigated by us. In total, only in 36 of the 138 cases investigated the overexposure was confirmed by cytogenetic dosimetry. The data indicates a total confirmation index of just 26% of the suspected cases.(author)

  19. Short periodic oscillations of the dwarf nova VW Hydri

    International Nuclear Information System (INIS)

    Haefner, R.; Schoembs, R.

    1977-01-01

    A coherent oscillation of approximately 88 s period and 0.m005 amplitude was detected during the decline stage at the end of the long eruption of VW Hyi in December 1975. The period changed erratically between 86 and 90 s during eight nights. There are indications that the amplitude depends on the phase of the orbital revolution. The new period favours models in which such oscillations are caused by the orbital motion of inhomogeneities in the disc. (orig.) [de

  20. Raccoon eyes and the MIBG super scan: scintigraphic signs of neuroblastoma in a case of suspected child abuse

    International Nuclear Information System (INIS)

    Bohdiewicz, P.J.; Gallegos, E.; Fink-Bennett, D.

    1995-01-01

    The authors report on an infant suspected of having been abused, who presented with periorbital edema and ecchymoses (clinial 'raccoon eyes'). The pattern of the nuclear medicine bone scan suggested neuroblastoma rather than trauma. Both the bone scan and the subsequent MIBG scan revealed multiple abnormalities, including markedly increased activity around the orbits, that we termed the 'scintigraphic raccoon eyes' sign. In addition, the grossly abnormal MIBG scan demonstrated avid uptake of MIBG throughout the entire skeleton with essentially complete absence of visualization of the liver and heart (the 'MIBG super scan'). These signs have not previously been described in an infant or a child with neuroblastoma. (orig.)

  1. Raccoon eyes and the MIBG super scan: scintigraphic signs of neuroblastoma in a case of suspected child abuse

    Energy Technology Data Exchange (ETDEWEB)

    Bohdiewicz, P.J. [Nuclear Medicine Dept., William Beaumont Hospital, Royal Oak, MI (United States); Gallegos, E. [Nuclear Medicine Dept., William Beaumont Hospital, Royal Oak, MI (United States); Fink-Bennett, D. [Nuclear Medicine Dept., William Beaumont Hospital, Royal Oak, MI (United States)

    1995-11-01

    The authors report on an infant suspected of having been abused, who presented with periorbital edema and ecchymoses (clinial `raccoon eyes`). The pattern of the nuclear medicine bone scan suggested neuroblastoma rather than trauma. Both the bone scan and the subsequent MIBG scan revealed multiple abnormalities, including markedly increased activity around the orbits, that we termed the `scintigraphic raccoon eyes` sign. In addition, the grossly abnormal MIBG scan demonstrated avid uptake of MIBG throughout the entire skeleton with essentially complete absence of visualization of the liver and heart (the `MIBG super scan`). These signs have not previously been described in an infant or a child with neuroblastoma. (orig.)

  2. Believable Suspect Agents: Response and Interpersonal Style Selection for an Artificial Suspect

    NARCIS (Netherlands)

    Bruijnes, Merijn

    2016-01-01

    The social skills necessary to properly and successfully conduct a police interrogation can and need to be trained. In the thesis I will describe the steps I took towards a virtual character that can play the role of a suspect in a police interrogation training. Students of the police academy will

  3. Orbital resonances of Taiwan's FORMOSAT-2 remote sensing satellite

    Science.gov (United States)

    Lin, Shin-Fa; Hwang, Cheinway

    2018-06-01

    Unlike a typical remote sensing satellite that has a global coverage and non-integral orbital revolutions per day, Taiwan's FORMOSAT-2 (FS-2) satellite has a non-global coverage due to the mission requirements of one-day repeat cycle and daily visit around Taiwan. These orbital characteristics result in an integer number of revolutions a day and orbital resonances caused by certain components of the Earth's gravity field. Orbital flight data indicated amplified variations in the amplitudes of FS-2's Keplerian elements. We use twelve years of orbital observations and maneuver data to analyze the cause of the resonances and explain the differences between the simulated (at the pre-launch stage) and real orbits of FS-2. The differences are quantified using orbital perturbation theories that describe secular and long-period orbital evolutions caused by resonances. The resonance-induced orbital rising rate of FS-2 reaches +1.425 m/day, due to the combined (modeled) effect of resonances and atmospheric drags (the relative modeling errors remote sensing mission similar to FS-2, especially in the early mission design and planning phase.

  4. Substituent effects on the optical properties of naphthalenediimides: A frontier orbital analysis across the periodic table.

    Science.gov (United States)

    Mulder, Joshua R; Guerra, Célia Fonseca; Slootweg, J Chris; Lammertsma, Koop; Bickelhaupt, F Matthias

    2016-01-15

    A comprehensive theoretical treatment is presented for the electronic excitation spectra of ca. 50 different mono-, di-, and tetrasubstituted naphthalenediimides (NDI) using time-dependent density functional theory (TDDFT) at ZORA-CAM-B3LYP/TZ2P//ZORA-BP86/TZ2P with COSMO for simulating the effect of dichloromethane (DCM) solution. The substituents -XHn are from groups 14-17 and rows 2-5 of the periodic table. The lowest dipole-allowed singlet excitation (S0 -S1 ) of the monosubstituted NDIs can be tuned from 3.39 eV for -F to 2.42 eV for -TeH, while the S0 -S2 transition is less sensitive to substitution with energies ranging between 3.67 eV for -CH3 and 3.44 eV for -SbH2 . In the case of NDIs with group-15 and -16 substituents, the optical transitions strongly depend on the extent to which -XHn is planar or pyramidal as well as on the possible formation of intramolecular hydrogen bonds. The accumulative effect of double and quadruple substitution leads in general to increasing bathochromic shifts, but the increased steric hindrance in tetrasubstituted NDIs can lead to deformations that diminish the effectiveness of the substituents. Detailed analyses of the Kohn-Sham orbital electronic structure in monosubstituted NDIs reveal the mesomeric destabilization of the HOMO as the primary cause of the bathochromic shift of the S0-S1 transition. © 2015 Wiley Periodicals, Inc.

  5. 48 CFR 1403.303 - Reporting suspected antitrust violations.

    Science.gov (United States)

    2010-10-01

    ... Antitrust Violations 1403.303 Reporting suspected antitrust violations. (a) Reports on suspected violations of antitrust laws as required by FAR 3.303 shall be prepared by the CO, reviewed by the SOL, and... antitrust violations. 1403.303 Section 1403.303 Federal Acquisition Regulations System DEPARTMENT OF THE...

  6. Investigation of an orbital mass - the role of nuclear medicine

    International Nuclear Information System (INIS)

    Dunlop, R. V.

    2009-01-01

    Full text:A 35 year old male presented, suffering from night sweats, occipital and frontal headaches, blurred vision, nausea and a decrease in appetite. He underwent a CT and MRI scan, which identified a 2.2cm lesion in the left orbit in an intra-conal position. This was suspected to be a cavernous haemangioma, although other tumours, such as Schwannoma could not be ruled out. A nuclear medicine labelled red blood cell study was performed which included initial dynamic images and early statics and 120min delayed images. SPECT/CT was also performed at the later time. The characteristic blood pool mismatch of low early and high delayed concentration of red blood cells confirmed suspicions of a cavernous haemangioma, which, although comprised mainly of blood vessels, has slow flow. Hence there is considerable delay before maximum activity is reached. The lesion was surgically removed. Histology reports confirmed the nuclear medicine results. Nuclear Medicine has the potential to play a significant role in the preoperative diagnosis of an orbital mass.

  7. V/P SPECT as a diagnostic tool for pregnant women with suspected pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Bajc, Marika; Olsson, Berit; Joegi, Jonas [Skaane University Hospital and Lund University, Clinical Physiology and Nuclear Medicine, Lund (Sweden); Gottsaeter, Anders [Skaane University Hospital, Vascular Diseases, Malmoe (Sweden); Hindorf, Cecilia [Skaane University Hospital, Radiation Physics, Lund (Sweden)

    2015-07-15

    The purpose of the study was to assess the prevalence of pulmonary embolism (PE) and other lung diseases among pregnant women with suspected PE and to calculate the radiation exposure to patient and fetus in this population. As a secondary aim, we evaluated the negative predictive value of a normal ventilation/perfusion single photon emission computed tomography (V/P SPECT) examination in pregnancy. We studied all 127 pregnant women who had suspected PE and had undergone V/P SPECT at our institution in the course of a 5-year period. Radiation exposure to patient and fetus and the negative predictive value of a normal V/P SPECT examination were also measured. V/P SPECT identified PE in 11 women (9 %). Moreover, in 15 women (12 %) the examination revealed pneumonia (in 2 cases in addition to PE) and in 1 woman signs of airway obstruction were revealed. Among the 116/127 women (91 %) where PE was ruled out by V/P SPECT, none was diagnosed subsequently with PE or deep venous thrombosis (DVT) during the same pregnancy or puerperal period. For P SPECT, the calculated fetal absorbed dose was < 0.6 mGy,and the calculated breast absorbed dose 0.6 mGy. For V SPECT, the calculated fetal absorbed dose was < 0.014 mGy and the breast absorbed dose 0.25 mGy. The prevalence of PE was low (9 %) among pregnant women with suspected disease. Pneumonia was diagnosed in 12 % of patients. The negative predictive value of V/P SPECT was high, and the radiation exposure from V/P SPECT was low both for fetus and patient. (orig.)

  8. Long-term orbit prediction for Tiangong-1 spacecraft using the mean atmosphere model

    Science.gov (United States)

    Tang, Jingshi; Liu, Lin; Cheng, Haowen; Hu, Songjie; Duan, Jianfeng

    2015-03-01

    China is planning to complete its first space station by 2020. For the long-term management and maintenance, the orbit of the space station needs to be predicted for a long period of time. Since the space station is expected to work in a low-Earth orbit, the error in the a priori atmosphere model contributes significantly to the rapid increase of the predicted orbit error. When the orbit is predicted for 20 days, the error in the a priori atmosphere model, if not properly corrected, could induce a semi-major axis error of up to a few kilometers and an overall position error of several thousand kilometers respectively. In this work, we use a mean atmosphere model averaged from NRLMSISE00. The a priori reference mean density can be corrected during the orbit determination. For the long-term orbit prediction, we use sufficiently long period of observations and obtain a series of the diurnal mean densities. This series contains the recent variation of the atmosphere density and can be analyzed for various periodic components. After being properly fitted, the mean density can be predicted and then applied in the orbit prediction. Here we carry out the test with China's Tiangong-1 spacecraft at the altitude of about 340 km and we show that this method is simple and flexible. The densities predicted with this approach can serve in the long-term orbit prediction. In several 20-day prediction tests, most predicted orbits show semi-major axis errors better than 700 m and overall position errors better than 400 km.

  9. Saturn's Magnetic Field from the Cassini Grand Finale orbits

    Science.gov (United States)

    Dougherty, M. K.; Cao, H.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

    2017-12-01

    The fundamental aims of the Cassini magnetometer investigation during the Cassini Grand Finale orbits were determination of Saturn's internal planetary magnetic field and the rotation rate of the deep interior. The unique geometry of the orbits provided an unprecedented opportunity to measure the intrinsic magnetic field at close distances never before encountered. The surprising close alignment of Saturn's magnetic axis with its spin axis, known about since the days of Pioneer 11, has been a focus of the team's analysis since Cassini Saturn Orbit Insertion. However, the varying northern and southern magnetospheric planetary period oscillations, which fill the magnetosphere, has been a factor in masking the field signals from the interior. Here we describe an overview of the magnetometer results from the Grand Finale orbits, including confirmation of the extreme axisymmetric nature of the planetary magnetic field, implications for knowledge of the rotation rate and the behaviour of external magnetic fields (arising from the ring current, field aligned currents both at high and low latitudes and the modulating effect of the planetary period oscillations).

  10. Computed tomographic features of orbital lesions

    International Nuclear Information System (INIS)

    Azevedo, C.M. de; Hoch, H.; Azevedo, M. de L.

    1990-01-01

    The purpose of this m anuscript is to present the use of CT in the evaluation of 42 cases of orbital lesions studied at the National Institute of Cancer in an one year and half period. Correlation with clinical and pathological data was performed and the results compared with those of the literature. Four cases of rare lesions are shown: alveolar soft tissue sarcoma, giant cell tumor and hematogenic metastatic deposits of a clear cell sarcoma and epidermoid carcinoma. The value of CT in the evaluation of all orbital masses is emphasized. (author) [pt

  11. A UNIFIED FRAMEWORK FOR THE ORBITAL STRUCTURE OF BARS AND TRIAXIAL ELLIPSOIDS

    Energy Technology Data Exchange (ETDEWEB)

    Valluri, Monica; Abbott, Caleb [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Shen, Juntai [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Debattista, Victor P., E-mail: mvalluri@umich.edu, E-mail: calebga@umich.edu, E-mail: jshen@shao.ac.cn, E-mail: vpdebattista@uclan.ac.uk [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)

    2016-02-20

    We examine a large random sample of orbits in two self-consistent simulations of N-body bars. Orbits in these bars are classified both visually and with a new automated orbit classification method based on frequency analysis. The well-known prograde x1 orbit family originates from the same parent orbit as the box orbits in stationary and rotating triaxial ellipsoids. However, only a small fraction of bar orbits (∼4%) have predominately prograde motion like their periodic parent orbit. Most bar orbits arising from the x1 orbit have little net angular momentum in the bar frame, making them equivalent to box orbits in rotating triaxial potentials. In these simulations a small fraction of bar orbits (∼7%) are long-axis tubes that behave exactly like those in triaxial ellipsoids: they are tipped about the intermediate axis owing to the Coriolis force, with the sense of tipping determined by the sign of their angular momentum about the long axis. No orbits parented by prograde periodic x2 orbits are found in the pure bar model, but a tiny population (∼2%) of short-axis tube orbits parented by retrograde x4 orbits are found. When a central point mass representing a supermassive black hole (SMBH) is grown adiabatically at the center of the bar, those orbits that lie in the immediate vicinity of the SMBH are transformed into precessing Keplerian orbits that belong to the same major families (short-axis tubes, long-axis tubes and boxes) occupying the bar at larger radii. During the growth of an SMBH, the inflow of mass and outward transport of angular momentum transform some x1 and long-axis tube orbits into prograde short-axis tubes. This study has important implications for future attempts to constrain the masses of SMBHs in barred galaxies using orbit-based methods like the Schwarzschild orbit superposition scheme and for understanding the observed features in barred galaxies.

  12. K2-137 b: an Earth-sized planet in a 4.3-h orbit around an M-dwarf

    DEFF Research Database (Denmark)

    Smith, A. M. S.; Cabrera, J.; Csizmadia, Sz

    2018-01-01

    We report the discovery in K2's Campaign 10 of a transiting terrestrial planet in an ultra-short-period orbit around an M3-dwarf. K2-137 b completes an orbit in only 4.3 h, the second shortest orbital period of any known planet, just 4 min longer than that of KOI 1843.03, which also orbits an M-d...

  13. Explore Stochastic Instabilities of Periodic Points by Transition Path Theory

    Science.gov (United States)

    Cao, Yu; Lin, Ling; Zhou, Xiang

    2016-06-01

    We consider the noise-induced transitions from a linearly stable periodic orbit consisting of T periodic points in randomly perturbed discrete logistic map. Traditional large deviation theory and asymptotic analysis at small noise limit cannot distinguish the quantitative difference in noise-induced stochastic instabilities among the T periodic points. To attack this problem, we generalize the transition path theory to the discrete-time continuous-space stochastic process. In our first criterion to quantify the relative instability among T periodic points, we use the distribution of the last passage location related to the transitions from the whole periodic orbit to a prescribed disjoint set. This distribution is related to individual contributions to the transition rate from each periodic points. The second criterion is based on the competency of the transition paths associated with each periodic point. Both criteria utilize the reactive probability current in the transition path theory. Our numerical results for the logistic map reveal the transition mechanism of escaping from the stable periodic orbit and identify which periodic point is more prone to lose stability so as to make successful transitions under random perturbations.

  14. Shell structure and orbit bifurcations in finite fermion systems

    Science.gov (United States)

    Magner, A. G.; Yatsyshyn, I. S.; Arita, K.; Brack, M.

    2011-10-01

    We first give an overview of the shell-correction method which was developed by V.M. Strutinsky as a practicable and efficient approximation to the general self-consistent theory of finite fermion systems suggested by A.B. Migdal and collaborators. Then we present in more detail a semiclassical theory of shell effects, also developed by Strutinsky following original ideas of M.C. Gutzwiller. We emphasize, in particular, the influence of orbit bifurcations on shell structure. We first give a short overview of semiclassical trace formulae, which connect the shell oscillations of a quantum system with a sum over periodic orbits of the corresponding classical system, in what is usually called the "periodic orbit theory". We then present a case study in which the gross features of a typical double-humped nuclear fission barrier, including the effects of mass asymmetry, can be obtained in terms of the shortest periodic orbits of a cavity model with realistic deformations relevant for nuclear fission. Next we investigate shell structures in a spheroidal cavity model which is integrable and allows for far-going analytical computation. We show, in particular, how period-doubling bifurcations are closely connected to the existence of the so-called "superdeformed" energy minimum which corresponds to the fission isomer of actinide nuclei. Finally, we present a general class of radial power-law potentials which approximate well the shape of a Woods-Saxon potential in the bound region, give analytical trace formulae for it and discuss various limits (including the harmonic oscillator and the spherical box potentials).

  15. Satellite Orbital Precessions Caused by the Octupolar Mass Moment ...

    Indian Academy of Sciences (India)

    Abstract. I consider a satellite moving around a non-spherical body of mass M and equatorial radius R, and calculate its orbital precessions caused by the body's octupolar mass moment J4. I consider only the effects averaged over one orbital period T of the satellite. I give exact for- mulas, not restricted to any special values ...

  16. RHIC 10 Hz global orbit feedback system

    International Nuclear Information System (INIS)

    Michnoff, R.; Arnold, L.; Carboni, L.; Cerniglia, P.; Curcio, A.; DeSanto, L.; Folz, C.; Ho, C.; Hoff, L.; Hulsart, R.; Karl, R.; Luo, Y.; Liu, C.; MacKay, W.; Mahler, G.; Meng, W.; Mernick, K.; Minty, M.; Montag, C.; Olsen, R.; Piacentino, J.; Popken, P.; Przybylinski, R.; Ptitsyn, V.; Ritter, J.; Schoenfeld, R.; Thieberger, P.; Tuozzolo, J.; Weston, A.; White, J.; Ziminski, P.; Zimmerman, P.

    2011-01-01

    Vibrations of the cryogenic triplet magnets at the Relativistic Heavy Ion Collider (RHIC) are suspected to be causing the horizontal beam perturbations observed at frequencies around 10 Hz. Several solutions to counteract the effect have been considered in the past, including a local beam feedback system at each of the two experimental areas, reinforcing the magnet base support assembly, and a mechanical servo feedback system. However, the local feedback system was insufficient because perturbation amplitudes outside the experimental areas were still problematic, and the mechanical solutions are very expensive. A global 10 Hz orbit feedback system consisting of 36 beam position monitors (BPMs) and 12 small dedicated dipole corrector magnets in each of the two 3.8 km circumference counter-rotating rings has been developed and commissioned in February 2011. A description of the system architecture and results with beam will be discussed.

  17. Suspects in criminal investigations of rape

    Directory of Open Access Journals (Sweden)

    Marinković Darko

    2014-01-01

    Full Text Available Investigations of sexual assaults mostly focus on victims and their credibility, which may cause lack of firm evidence in relation to suspects. Given the fact that the criminal offence of rape is characterised by a high incidence of false reports and accusations, frequently indicating specific persons as the perpetrators, certain caution is necessary in the investigation in order to avoid false accusations and/or convictions. As regards the personality of the rapist and motives for committing a forcible sexual act, certain types or rather certain categories of perpetrators can be distinguished, although it should be noted that a large number of rapists do not belong to one category only, but rather combine characteristics of several different types. During a criminal investigation it is of vital importance to differentiate between a rape as a surprise attack and a rape as abuse of trust, as they are compatible with the nature of the suspect's defence. The suspect shall be subjected to a forensic examination in the course of the investigation in order to find traces which prove vaginal, anal or oral penetration, coerced sexual intercourse and identity of the rapist. While conducting an interrogation of a suspected rapist, a crime investigating officer shall use either factual or emotional approach to his interviewee, depending on his psychological and motivational characteristics. In this regard, the factual approach is believed to be more efficient with anger rapists and sadistic rapists, whereas the compassionate approach gives good results with the gentlemen-rapists and partly with the power asserting rapists.

  18. Dynamic orbital textures in 3He-A

    International Nuclear Information System (INIS)

    Hall, H.E.; Hook, J.R.; Main, P.C.; Bagley, M.

    1978-01-01

    Three related pieces of work on the dynamic orbital texture of 3 He-A in a slab geometry have been carried out. (1) The non-linear equation of motion of the orbital axis has been studied analytically and numerically for heat flow normal to a slab. If the product of counter-flow velocity and slab thickness is greater than 5 π h/3 m, the lower energy uniform texture is unstable, and persistent orbital oscillation results in. (2) The torsion pendulum experiment has demonstrated the alignment of l by flow in a channel of width 380 μm. In this experiment, the oscillation was rapid as compared with the orbital relaxation time, so that the texture is controlled by the root mean square velocity. (3) In an attempt to observe directly the dissipation by orbital viscosity, the torsion pendulum experiment has been repeated with 17μm flow channels, for which orbital relaxation time and oscillation period should be comparable. Dissipation above a critical amplitude that occurs in the A-phase but not in the B-phase was observed. The dissipation is of the expected magnitude. (Kobatake, H

  19. Impact of ITRS 2014 realizations on altimeter satellite precise orbit determination

    Science.gov (United States)

    Zelensky, Nikita P.; Lemoine, Frank G.; Beckley, Brian D.; Chinn, Douglas S.; Pavlis, Despina E.

    2018-01-01

    This paper evaluates orbit accuracy and systematic error for altimeter satellite precise orbit determination on TOPEX, Jason-1, Jason-2 and Jason-3 by comparing the use of four SLR/DORIS station complements from the International Terrestrial Reference System (ITRS) 2014 realizations with those based on ITRF2008. The new Terrestrial Reference Frame 2014 (TRF2014) station complements include ITRS realizations from the Institut National de l'Information Géographique et Forestière (IGN) ITRF2014, the Jet Propulsion Laboratory (JPL) JTRF2014, the Deutsche Geodätisches Forschungsinstitut (DGFI) DTRF2014, and the DORIS extension to ITRF2014 for Precise Orbit Determination, DPOD2014. The largest source of error stems from ITRF2008 station position extrapolation past the 2009 solution end time. The TRF2014 SLR/DORIS complement impact on the ITRF2008 orbit is only 1-2 mm RMS radial difference between 1992-2009, and increases after 2009, up to 5 mm RMS radial difference in 2016. Residual analysis shows that station position extrapolation error past the solution span becomes evident even after two years, and will contribute to about 3-4 mm radial orbit error after seven years. Crossover data show the DTRF2014 orbits are the most accurate for the TOPEX and Jason-2 test periods, and the JTRF2014 orbits for the Jason-1 period. However for the 2016 Jason-3 test period only the DPOD2014-based orbits show a strong and statistically significant margin of improvement. The positive results with DTRF2014 suggest the new approach to correct station positions or normal equations for non-tidal loading before combination is beneficial. We did not find any compelling POD advantage in using non-linear over linear station velocity models in our SLR & DORIS orbit tests on the Jason satellites. The JTRF2014 proof-of-concept ITRS realization demonstrates the need for improved SLR+DORIS orbit centering when compared to the Ries (2013) CM annual model. Orbit centering error is seen as an annual

  20. Solar radiation pressure and deviations from Keplerian orbits

    Energy Technology Data Exchange (ETDEWEB)

    Kezerashvili, Roman Ya. [Physics Department, New York City College of Technology, the City University of New York, Brooklyn, NY 11201 (United States); Vazquez-Poritz, Justin F. [Physics Department, New York City College of Technology, City University of New York, Brooklyn, NY 11201 (United States)], E-mail: jporitz@gmail.com

    2009-05-04

    Newtonian gravity and general relativity give exactly the same expression for the period of an object in circular orbit around a static central mass. However, when the effects of the curvature of spacetime and solar radiation pressure are considered simultaneously for a solar sail propelled satellite, there is a deviation from Kepler's third law. It is shown that solar radiation pressure affects the period of this satellite in two ways: by effectively decreasing the solar mass, thereby increasing the period, and by enhancing the effects of other phenomena, potentially rendering some of them detectable. In particular, we consider deviations from Keplerian orbits due to spacetime curvature, frame dragging from the rotation of the sun, the oblateness of the sun, a possible net electric charge of the sun, and a very small positive cosmological constant.

  1. EG Andromedae: A New Orbit and Additional Evidence for a Photoionized Wind

    Science.gov (United States)

    Kenyon, Scott J.; Garcia, Michael R.

    2016-07-01

    We analyze a roughly 20 yr set of spectroscopic observations for the symbiotic binary EG And. Radial velocities derived from echelle spectra are best fit with a circular orbit having an orbital period of P = 483.3 ± 1.6 days and semi-amplitude K = 7.34 ± 0.07 km s-1. Combined with previous data, these observations rule out an elliptical orbit at the 10σ level. Equivalent widths of H I Balmer emission lines and various absorption features vary in phase with the orbital period. Relative to the radius of the red giant primary, the apparent size of the H II region is consistent with a model where a hot secondary star with effective temperature T h ≈ 75,000 K ionizes the wind from the red giant.

  2. Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2002 – February 2003

    Directory of Open Access Journals (Sweden)

    V. Naidoo

    2003-07-01

    Full Text Available The Veterinary Pharmacovigilance and Medicines Information Centre is responsible for the monitoring of veterinary adverse drug reactions in South Africa. An overview of reports of suspected adverse drug reactions received by the centre during the period March 2002 to February 2003 is given. In total, 40 reports were received. This had declined from the previous year. Most reports involved suspected adverse reactions that occurred in dogs and cats. Most of the products implicated were Stock Remedies. The animal owner predominantly administered these products. Only 1 report was received from a veterinary pharmaceutical company. Increasing numbers of reports are being received from veterinarians.

  3. A Search for Exoplanets in Short-Period Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Ronald Kaitchuck

    2012-03-01

    Full Text Available This paper reports the progress of a search for exoplanets with S-type orbits in short-period binary star systems. The selected targets have stellar orbital periods of just a few days. These systems are eclipsing binaries so that exoplanet transits, if planets exist, will be highly likely. We report the results for seven binary star systems.

  4. KEPLER-1647B: THE LARGEST AND LONGEST-PERIOD KEPLER TRANSITING CIRCUMBINARY PLANET

    Energy Technology Data Exchange (ETDEWEB)

    Kostov, Veselin B. [NASA Goddard Space Flight Center, Mail Code 665, Greenbelt, MD 20771 (United States); Orosz, Jerome A.; Welsh, William F.; Short, Donald R. [Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States); Doyle, Laurance R. [SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Principia College, IMoP, One Maybeck Place, Elsah, IL 62028 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Haghighipour, Nader [Institute for Astronomy, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Quarles, Billy [Department of Physics and Physical Science, The University of Nebraska at Kearney, Kearney, NE 68849 (United States); Cochran, William D.; Endl, Michael [McDonald Observatory, The University of Texas as Austin, Austin, TX 78712-0259 (United States); Ford, Eric B. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 428A Davey Lab, University Park, PA 16802 (United States); Gregorio, Joao [Atalaia Group and Crow-Observatory, Portalegre (Portugal); Hinse, Tobias C. [Korea Astronomy and Space Science Institute (KASI), Advanced Astronomy and Space Science Division, Daejeon 305-348 (Korea, Republic of); Isaacson, Howard [Department of Astronomy, University of California Berkeley, 501 Campbell Hall, Berkeley, CA 94720 (United States); Jenkins, Jon M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Kane, Stephen [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Kull, Ilya, E-mail: veselin.b.kostov@nasa.gov [Department of Astronomy and Astrophysics, Tel Aviv University, 69978 Tel Aviv (Israel); and others

    2016-08-10

    We report the discovery of a new Kepler transiting circumbinary planet (CBP). This latest addition to the still-small family of CBPs defies the current trend of known short-period planets orbiting near the stability limit of binary stars. Unlike the previous discoveries, the planet revolving around the eclipsing binary system Kepler-1647 has a very long orbital period (∼1100 days) and was at conjunction only twice during the Kepler mission lifetime. Due to the singular configuration of the system, Kepler-1647b is not only the longest-period transiting CBP at the time of writing, but also one of the longest-period transiting planets. With a radius of 1.06 ± 0.01 R {sub Jup}, it is also the largest CBP to date. The planet produced three transits in the light curve of Kepler-1647 (one of them during an eclipse, creating a syzygy) and measurably perturbed the times of the stellar eclipses, allowing us to measure its mass, 1.52 ± 0.65 M {sub Jup}. The planet revolves around an 11-day period eclipsing binary consisting of two solar-mass stars on a slightly inclined, mildly eccentric ( e {sub bin} = 0.16), spin-synchronized orbit. Despite having an orbital period three times longer than Earth’s, Kepler-1647b is in the conservative habitable zone of the binary star throughout its orbit.

  5. KEPLER-1647B: THE LARGEST AND LONGEST-PERIOD KEPLER TRANSITING CIRCUMBINARY PLANET

    International Nuclear Information System (INIS)

    Kostov, Veselin B.; Orosz, Jerome A.; Welsh, William F.; Short, Donald R.; Doyle, Laurance R.; Fabrycky, Daniel C.; Haghighipour, Nader; Quarles, Billy; Cochran, William D.; Endl, Michael; Ford, Eric B.; Gregorio, Joao; Hinse, Tobias C.; Isaacson, Howard; Jenkins, Jon M.; Jensen, Eric L. N.; Kane, Stephen; Kull, Ilya

    2016-01-01

    We report the discovery of a new Kepler transiting circumbinary planet (CBP). This latest addition to the still-small family of CBPs defies the current trend of known short-period planets orbiting near the stability limit of binary stars. Unlike the previous discoveries, the planet revolving around the eclipsing binary system Kepler-1647 has a very long orbital period (∼1100 days) and was at conjunction only twice during the Kepler mission lifetime. Due to the singular configuration of the system, Kepler-1647b is not only the longest-period transiting CBP at the time of writing, but also one of the longest-period transiting planets. With a radius of 1.06 ± 0.01 R Jup , it is also the largest CBP to date. The planet produced three transits in the light curve of Kepler-1647 (one of them during an eclipse, creating a syzygy) and measurably perturbed the times of the stellar eclipses, allowing us to measure its mass, 1.52 ± 0.65 M Jup . The planet revolves around an 11-day period eclipsing binary consisting of two solar-mass stars on a slightly inclined, mildly eccentric ( e bin = 0.16), spin-synchronized orbit. Despite having an orbital period three times longer than Earth’s, Kepler-1647b is in the conservative habitable zone of the binary star throughout its orbit.

  6. Period changes of cataclysmic variables below the period gap: V2051 Oph, OY Car and Z Cha

    Science.gov (United States)

    Pilarčík, L.; Wolf, M.; Zasche, P.; Vraštil, J.

    2018-04-01

    We present our results of a long-term monitoring of cataclysmic variable stars (CVs). About 40 new eclipses were measured for the three southern SU UMa-type eclipsing CVs: V2051 Oph, OY Car and Z Cha. Based on the current O - C diagrams we confirmed earlier findings that V2051 Oph and OY Car present cyclic changes of their orbital periods lasting 25 and 29 years, respectively. In case of Z Cha we propose the light-time effect caused probably by a presence of the third component orbiting the eclipsing CV with the period of 43.5 years. The minimal mass of this companion results about 15 MJup.

  7. Co-periodic stability of periodic waves in some Hamiltonian PDEs

    Science.gov (United States)

    Benzoni-Gavage, S.; Mietka, C.; Rodrigues, L. M.

    2016-10-01

    The stability of periodic traveling wave solutions to dispersive PDEs with respect to ‘arbitrary’ perturbations is still widely open. The focus is put here on stability with respect to perturbations of the same period as the wave, for KdV-like systems of one-dimensional Hamiltonian PDEs. Stability criteria are derived and investigated first in a general abstract framework, and then applied to three basic examples that are very closely related, and ubiquitous in mathematical physics, namely, a quasilinear version of the generalized Korteweg-de Vries equation (qKdV), and the Euler-Korteweg system in both Eulerian coordinates (EKE) and in mass Lagrangian coordinates (EKL). Those criteria consist of a necessary condition for spectral stability, and of a sufficient condition for orbital stability. Both are expressed in terms of a single function, the abbreviated action integral along the orbits of waves in the phase plane, which is the counterpart of the solitary waves moment of instability introduced by Boussinesq. Regarding solitary waves, the celebrated Grillakis-Shatah-Strauss stability criteria amount to looking for the sign of the second derivative of the moment of instability with respect to the wave speed. For periodic waves, the most striking results obtained here can be summarized as: an odd value for the difference between N—the size of the PDE system—and the negative signature of the Hessian of the action implies spectral instability, whereas a negative signature of the same Hessian being equal to N implies orbital stability. Since these stability criteria are merely encoded by the negative signature of matrices, they can at least be checked numerically. Various numerical experiments are presented, which clearly discriminate between stable cases and unstable cases for (qKdV), (EKE) and (EKL).

  8. SPIN-ORBIT ALIGNMENT FOR THE CIRCUMBINARY PLANET HOST KEPLER-16 A

    International Nuclear Information System (INIS)

    Winn, Joshua N.; Albrecht, Simon; Johnson, John Asher; Torres, Guillermo; Carter, Joshua A.; Ragozzine, Darin; Quinn, Samuel N.; Latham, David W.; Cochran, William D.; Marcy, Geoffrey W.; Howard, Andrew W.; Isaacson, Howard; Fischer, Debra; Doyle, Laurance; Welsh, William; Orosz, Jerome; Fabrycky, Daniel C.; Shporer, Avi; Howell, Steve B.; Prsa, Andrej

    2011-01-01

    Kepler-16 is an eccentric low-mass eclipsing binary with a circumbinary transiting planet. Here, we investigate the angular momentum of the primary star, based on Kepler photometry and Keck spectroscopy. The primary star's rotation period is 35.1 ± 1.0 days, and its projected obliquity with respect to the stellar binary orbit is 1. 0 6 ± 2. 0 4. Therefore, the three largest sources of angular momentum-the stellar orbit, the planetary orbit, and the primary's rotation-are all closely aligned. This finding supports a formation scenario involving accretion from a single disk. Alternatively, tides may have realigned the stars despite their relatively wide separation (0.2 AU), a hypothesis that is supported by the agreement between the measured rotation period and the 'pseudosynchronous' period of tidal evolution theory. The rotation period, chromospheric activity level, and fractional light variations suggest a main-sequence age of 2-4 Gyr. Evolutionary models of low-mass stars can match the observed masses and radii of the primary and secondary stars to within about 3%.

  9. Long-term orbit prediction for China's Tiangong-1 spacecraft based on mean atmosphere model

    Science.gov (United States)

    Tang, Jingshi; Liu, Lin; Miao, Manqian

    Tiangong-1 is China's test module for future space station. It has gone through three successful rendezvous and dockings with Shenzhou spacecrafts from 2011 to 2013. For the long-term management and maintenance, the orbit sometimes needs to be predicted for a long period of time. As Tiangong-1 works in a low-Earth orbit with an altitude of about 300-400 km, the error in the a priori atmosphere model contributes significantly to the rapid increase of the predicted orbit error. When the orbit is predicted for 10-20 days, the error in the a priori atmosphere model, if not properly corrected, could induce the semi-major axis error and the overall position error up to a few kilometers and several thousand kilometers respectively. In this work, we use a mean atmosphere model averaged from NRLMSIS00. The a priori reference mean density can be corrected during precise orbit determination (POD). For applications in the long-term orbit prediction, the observations are first accumulated. With sufficiently long period of observations, we are able to obtain a series of the diurnal mean densities. This series bears the recent variation of the atmosphere density and can be analyzed for various periods. After being properly fitted, the mean density can be predicted and then applied in the orbit prediction. We show that the densities predicted with this approach can serve to increase the accuracy of the predicted orbit. In several 20-day prediction tests, most predicted orbits show semi-major axis errors better than 700m and overall position errors better than 600km.

  10. Efficient orbit integration by manifold correction methods.

    Science.gov (United States)

    Fukushima, Toshio

    2005-12-01

    Triggered by a desire to investigate, numerically, the planetary precession through a long-term numerical integration of the solar system, we developed a new formulation of numerical integration of orbital motion named manifold correct on methods. The main trick is to rigorously retain the consistency of physical relations, such as the orbital energy, the orbital angular momentum, or the Laplace integral, of a binary subsystem. This maintenance is done by applying a correction to the integrated variables at each integration step. Typical methods of correction are certain geometric transformations, such as spatial scaling and spatial rotation, which are commonly used in the comparison of reference frames, or mathematically reasonable operations, such as modularization of angle variables into the standard domain [-pi, pi). The form of the manifold correction methods finally evolved are the orbital longitude methods, which enable us to conduct an extremely precise integration of orbital motions. In unperturbed orbits, the integration errors are suppressed at the machine epsilon level for an indefinitely long period. In perturbed cases, on the other hand, the errors initially grow in proportion to the square root of time and then increase more rapidly, the onset of which depends on the type and magnitude of the perturbations. This feature is also realized for highly eccentric orbits by applying the same idea as used in KS-regularization. In particular, the introduction of time elements greatly enhances the performance of numerical integration of KS-regularized orbits, whether the scaling is applied or not.

  11. Audit of a policy of magnetic resonance imaging with diffusion-weighted imaging as first-line neuroimaging for in-patients with clinically suspected acute stroke

    International Nuclear Information System (INIS)

    Buckley, B.T.; Wainwright, A.; Meagher, T.; Briley, D.

    2003-01-01

    AIM: To audit the feasibility and use of diffusion-weighted (DW) magnetic resonance imaging (MRI) as initial neuroimaging for in-patients with clinically suspected acute stroke. MATERIALS AND METHODS: In April 2000, MRI with DW and T2-weighted sequence was locally instituted as initial neuroimaging for patients with clinically suspected acute stroke. This retrospective study reviewed imaging performed for in-patients with suspected acute stroke over a 9-month period. Data were collected on image type, result and need for repeat imaging. RESULTS: During the study period, 124 patients had neuroimaging for suspected cerebrovascular accident, and 119 were MRI safe. Eighty-eight (73.9%) patients underwent DW MRI as first-line investigation. Five patients were not MRI safe and 31 had computed tomography (CT) as first-line imaging due to lack of available MRI capacity. Repeat neuroimaging was performed in 16 (12.9%) patients. Study times were comparable for both types of neuroimaging: a mean of 13 min for MRI and 11 min for CT. CONCLUSION: The audit standard was achieved in 88 (73.9%) patients. The use of DW MRI as a first-line investigation for patients with a clinical diagnosis of acute stroke is achievable in a district general hospital setting

  12. Audit of a policy of magnetic resonance imaging with diffusion-weighted imaging as first-line neuroimaging for in-patients with clinically suspected acute stroke

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, B.T.; Wainwright, A.; Meagher, T.; Briley, D

    2003-03-01

    AIM: To audit the feasibility and use of diffusion-weighted (DW) magnetic resonance imaging (MRI) as initial neuroimaging for in-patients with clinically suspected acute stroke. MATERIALS AND METHODS: In April 2000, MRI with DW and T2-weighted sequence was locally instituted as initial neuroimaging for patients with clinically suspected acute stroke. This retrospective study reviewed imaging performed for in-patients with suspected acute stroke over a 9-month period. Data were collected on image type, result and need for repeat imaging. RESULTS: During the study period, 124 patients had neuroimaging for suspected cerebrovascular accident, and 119 were MRI safe. Eighty-eight (73.9%) patients underwent DW MRI as first-line investigation. Five patients were not MRI safe and 31 had computed tomography (CT) as first-line imaging due to lack of available MRI capacity. Repeat neuroimaging was performed in 16 (12.9%) patients. Study times were comparable for both types of neuroimaging: a mean of 13 min for MRI and 11 min for CT. CONCLUSION: The audit standard was achieved in 88 (73.9%) patients. The use of DW MRI as a first-line investigation for patients with a clinical diagnosis of acute stroke is achievable in a district general hospital setting.

  13. Thyrotoxic periodic paralysis

    Directory of Open Access Journals (Sweden)

    Rojith Karandode Balakrishnan

    2011-01-01

    Full Text Available This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recovery after the medical intervention and was discharged after 24 hours with no residual paralysis. Thyrotoxic periodic paralysis (TPP is a complication of thyrotoxicosis, more common amongst males in Asia. It presents as acute flaccid paralysis in a case of hyperthyroidism with associated hypokalemia. The features of thyrotoxicosis may be subtle or absent. Thus, in cases of recurrent or acute flaccid muscle paralysis, it is important to consider thyrotoxicosis as one of the possible causes, and take measures accordingly.

  14. The clinical course of patients with suspected pulmonary embolism

    NARCIS (Netherlands)

    van Beek, E. J.; Kuijer, P. M.; Büller, H. R.; Brandjes, D. P.; Bossuyt, P. M.; ten Cate, J. W.

    1997-01-01

    BACKGROUND: The outcome of patients with suspected pulmonary embolism is known to a limited extent only. OBJECTIVE: To address this limited knowledge in a cohort in whom pulmonary embolism was proved or ruled out. METHODS: Consecutive patients with clinically suspected pulmonary embolism underwent

  15. Reconstruction of Midface and Orbital Wall Defects After Maxillectomy and Orbital Content Preservation With Titanium Mesh and Fascia Lata: 3-Year Follow-Up.

    Science.gov (United States)

    Motiee-Langroudi, Maziar; Harirchi, Iraj; Amali, Amin; Jafari, Mehrdad

    2015-12-01

    To describe the authors' experience in the reconstruction of patients after total maxillectomy with preservation of orbital contents for maxillary tumors using titanium mesh and autogenous fascia lata, where no setting for free flap reconstruction is available. Twelve consecutive patients with paranasal sinus tumors underwent total maxillectomy without orbital exenterations and primary reconstruction. The defects were reconstructed by titanium mesh in combination with autogenous fascia lata in the orbital floor performed by 1 surgical team. Titanium mesh (0.2 mm thick) was contoured and fixed to reconstruct the orbital floor and obtain midface projection. Fascia lata was used to cover the titanium mesh along the orbital floor to prevent fat entrapment in the mesh holes. The most common pathology was squamous cell carcinoma (50%). Patients' mean age was 45.66 years (33 to 74 yr). The mean follow-up period was 35.2 months (30 to 49 months). During follow-up, no infection or foreign body reaction was encountered. Extrusion of titanium mesh occurred in 4 patients who underwent postoperative radiotherapy. Two cases of mild diplopia at extreme gaze occurred early during the postoperative period that resolved after a few months. Placing fascia lata between the titanium mesh surface of the orbital implant and the orbital contents was successful in preventing long-term diplopia or dystopia. Nevertheless, exposure of the titanium implant through the skin surface represented a complication of this technique in 25% of patients. Further studies are required with head-to-head comparisons of artificial materials and free flaps for reconstruction of maxillectomy defects. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Unfair Lineups Make Witnesses More Likely to Confuse Innocent and Guilty Suspects.

    Science.gov (United States)

    Colloff, Melissa F; Wade, Kimberley A; Strange, Deryn

    2016-09-01

    Eyewitness-identification studies have focused on the idea that unfair lineups (i.e., ones in which the police suspect stands out) make witnesses more willing to identify the police suspect. We examined whether unfair lineups also influence subjects' ability to distinguish between innocent and guilty suspects and their ability to judge the accuracy of their identification. In a single experiment (N = 8,925), we compared three fair-lineup techniques used by the police with unfair lineups in which we did nothing to prevent distinctive suspects from standing out. Compared with the fair lineups, doing nothing not only increased subjects' willingness to identify the suspect but also markedly impaired subjects' ability to distinguish between innocent and guilty suspects. Accuracy was also reduced at every level of confidence. These results advance theory on witnesses' identification performance and have important practical implications for how police should construct lineups when suspects have distinctive features. © The Author(s) 2016.

  17. The use of psychoactive prescription drugs among DUI suspects.

    Science.gov (United States)

    Karjalainen, Karoliina; Haukka, Jari; Lintonen, Tomi; Joukamaa, Matti; Lillsunde, Pirjo

    2015-10-01

    The study seeks to increase understanding of the use of psychoactive prescription drugs among persons suspected of driving under the influence (DUI). We studied whether the use of prescribed psychoactive medication was associated with DUI, and examined the difference in the use of prescription drugs between DUI recidivists and those arrested only once. In this register-based study, persons suspected of DUI (n=29470) were drawn from the Register of DUI suspects, and an age- and gender-matched reference population (n=30043) was drawn from the Finnish general population. Data on prescription drug use was obtained by linkage to the National Prescription Register. The associations of DUI arrest and use of psychoactive prescription drugs in different DUI groups (findings for alcohol only, prescription drugs, prescription drugs and alcohol, illicit drugs) were estimated by using mixed-effect logistic regression. The use of psychoactive prescription drugs and DUI appeared to be strongly associated, with DUI suspects significantly more likely to use psychoactive prescription drugs compared to the reference population. Gender differences existed, with the use of benzodiazepines being more common among female DUI suspects. Moreover, DUI recidivists were more likely to use psychoactive prescription drugs compared to those arrested only once. In addition to alcohol and/or illicit drug use, a significant proportion of DUI suspects were using psychoactive prescription drugs. When prescribing psychoactive medication, especially benzodiazepines, physicians are challenged to screen for possible substance use problems and also to monitor for patients' alcohol or illicit drug use while being medicated. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. EG ANDROMEDAE: A NEW ORBIT AND ADDITIONAL EVIDENCE FOR A PHOTOIONIZED WIND

    International Nuclear Information System (INIS)

    Kenyon, Scott J.; Garcia, Michael R.

    2016-01-01

    We analyze a roughly 20 yr set of spectroscopic observations for the symbiotic binary EG And. Radial velocities derived from echelle spectra are best fit with a circular orbit having an orbital period of P = 483.3 ± 1.6 days and semi-amplitude K = 7.34 ± 0.07 km s −1 . Combined with previous data, these observations rule out an elliptical orbit at the 10 σ level. Equivalent widths of H i Balmer emission lines and various absorption features vary in phase with the orbital period. Relative to the radius of the red giant primary, the apparent size of the H ii region is consistent with a model where a hot secondary star with effective temperature T h ≈ 75,000 K ionizes the wind from the red giant.

  19. EG ANDROMEDAE: A NEW ORBIT AND ADDITIONAL EVIDENCE FOR A PHOTOIONIZED WIND

    Energy Technology Data Exchange (ETDEWEB)

    Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Garcia, Michael R., E-mail: skenyon@cfa.harvard.edu, E-mail: michael.r.garcia@nasa.gov [NASA Headquarters, Mail Suite 3Y28, 300 E Street SW, Washington, DC 20546-0001 (United States)

    2016-07-01

    We analyze a roughly 20 yr set of spectroscopic observations for the symbiotic binary EG And. Radial velocities derived from echelle spectra are best fit with a circular orbit having an orbital period of P = 483.3 ± 1.6 days and semi-amplitude K = 7.34 ± 0.07 km s{sup −1}. Combined with previous data, these observations rule out an elliptical orbit at the 10 σ level. Equivalent widths of H i Balmer emission lines and various absorption features vary in phase with the orbital period. Relative to the radius of the red giant primary, the apparent size of the H ii region is consistent with a model where a hot secondary star with effective temperature T{sub h} ≈ 75,000 K ionizes the wind from the red giant.

  20. Light equation in eclipsing binary CV Boo: third body candidate in elliptical orbit

    Science.gov (United States)

    Bogomazov, A. I.; Kozyreva, V. S.; Satovskii, B. L.; Krushevska, V. N.; Kuznyetsova, Y. G.; Ehgamberdiev, S. A.; Karimov, R. G.; Khalikova, A. V.; Ibrahimov, M. A.; Irsmambetova, T. R.; Tutukov, A. V.

    2016-12-01

    A short period eclipsing binary star CV Boo is tested for the possible existence of additional bodies in the system with a help of the light equation method. We use data on the moments of minima from the literature as well as from our observations during 2014 May-July. A variation of the CV Boo's orbital period is found with a period of {≈}75 d. This variation can be explained by the influence of a third star with a mass of {≈}0.4 M_{⊙} in an eccentric orbit with e≈0.9. A possibility that the orbital period changes on long time scales is discussed. The suggested tertiary companion is near the chaotic zone around the central binary, so CV Boo represents an interesting example to test its dynamical evolution. A list of 14 minima moments of the binary obtained from our observations is presented.

  1. External Periodic Force Control of a Single-Degree-of-Freedom Vibroimpact System

    Directory of Open Access Journals (Sweden)

    Jingyue Wang

    2013-01-01

    Full Text Available A single-degree-of-freedom mechanical model of vibro-impact system is established. Bifurcation and chaos in the system are revealed with the time history diagram, phase trajectory map, and Poincaré map. According to the bifurcation and chaos of the actual vibro-impact system, the paper puts forward external periodic force control strategy. The method of controlling chaos by external periodic force feedback controller is developed to guide chaotic motions towards regular motions. The stability of the control system is also analyzed especially by theory. By selecting appropriate feedback coefficients, the unstable periodic orbits of the original chaotic orbit can be stabilized to the stable periodic orbits. The effectiveness of this control method is verified by numerical simulation.

  2. The value of X-ray CT in orbital fractures

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Myung Hee; Lee, Jae Mun; Kim, Choon Yul; Bahk, Yong Whee [Catholic Medical College, Seoul (Korea, Republic of)

    1986-08-15

    On the pulse from the trauma transiting to posterior side of the orbit, orbital fractures are occurred through the weak point of the orbital wall. Invagination of soft tissue or entrapment of muscles may be associated with orbital fracture. In condition of inaccurate diagnosis, appropriate surgical repairment is impossible and complication such as diplopia or enophthalmia are developed. CT scan is diagnostic procedure which demonstrates accurately the site and state of orbital fracture, and its associated findings. The authors has been studied in 21 orbital CT scan to evaluate the relative value of plain X rays and CT scans in the diagnosis of orbital fractures during the period from January 1982 to September 1985. The conclusions were as follows: 1. Diagnostic rate was 100% by CT, 40% by initial and 80% by retrospective interpretation of conventional X-ray films. 2. Low X-ray diagnostic rate of medical wall fractures (26.7%) was due to thinness of the bone. 3. Medial wall fractures were associated with floor fractures in 46%. 4. Orbital soft tissue injuries and abnormalities of PNS were precisely evaluated by CT scan.

  3. How Do Earth-Sized, Short-Period Planets Form?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    Matching theory to observation often requires creative detective work. In a new study, scientists have used a clever test to reveal clues about the birth of speedy, Earth-sized planets.Former Hot Jupiters?Artists impression of a hot Jupiter with an evaporating atmosphere. [NASA/Ames/JPL-Caltech]Among the many different types of exoplanets weve observed, one unusual category is that of ultra-short-period planets. These roughly Earth-sized planets speed around their host stars at incredible rates, with periods of less than a day.How do planets in this odd category form? One popular theory is that they were previously hot Jupiters, especially massive gas giants orbiting very close to their host stars. The close orbit caused the planets atmospheres to be stripped away, leaving behind only their dense cores.In a new study, a team of astronomers led by Joshua Winn (Princeton University) has found a clever way to test this theory.Planetary radius vs. orbital period for the authors three statistical samples (colored markers) and the broader sample of stars in the California Kepler Survey. [Winn et al. 2017]Testing MetallicitiesStars hosting hot Jupiters have an interesting quirk: they typically have metallicities that are significantly higher than an average planet-hosting star. It is speculated that this is because planets are born from the same materials as their host stars, and hot Jupiters require the presence of more metals to be able to form.Regardless of the cause of this trend, if ultra-short-period planets are in fact the solid cores of former hot Jupiters, then the two categories of planets should have hosts with the same metallicity distributions. The ultra-short-period-planet hosts should therefore also be weighted to higher metallicities than average planet-hosting stars.To test this, the authors make spectroscopic measurements and gather data for a sample of stellar hosts split into three categories:64 ultra-short-period planets (orbital period shorter than a

  4. Analysis of the SPS Long Term Orbit Drifts

    Energy Technology Data Exchange (ETDEWEB)

    Velotti, Francesco [CERN; Bracco, Chiara [CERN; Cornelis, Karel [CERN; Drøsdal, Lene [CERN; Fraser, Matthew [CERN; Gianfelice-Wendt, Eliana [Fermilab; Goddard, Brennan [CERN; Kain, Verena [CERN; Meddahi, Malika [CERN

    2016-06-01

    The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain, and has to deliver the two high-intensity 450 GeV proton beams to the LHC. The transport from SPS to LHC is done through the two Transfer Lines (TL), TI2 and TI8, for Beam 1 (B1) and Beam 2 (B2) respectively. During the first LHC operation period Run 1, a long term drift of the SPS orbit was observed, causing changes in the LHC injection due to the resulting changes in the TL trajectories. This translated into longer LHC turnaround because of the necessity to periodically correct the TL trajectories in order to preserve the beam quality at injection into the LHC. Different sources for the SPS orbit drifts have been investigated: each of them can account only partially for the total orbit drift observed. In this paper, the possible sources of such drift are described, together with the simulated and measured effect they cause. Possible solutions and countermeasures are also discussed.

  5. Economic evaluation of a clinical protocol for diagnosing emergency patients with suspected pulmonary embolism

    Directory of Open Access Journals (Sweden)

    Wolfe Rory

    2006-06-01

    Full Text Available Abstract Background The objective of this paper is to estimate the amount of cost-savings to the Australian health care system from implementing an evidence-based clinical protocol for diagnosing emergency patients with suspected pulmonary embolism (PE at the Emergency department of a Victorian public hospital with 50,000 presentations in 2001–2002. Methods A cost-minimisation study used the data collected in a controlled clinical trial of a clinical protocol for diagnosing patients with suspected PE. Thenumber and type of diagnostic tests in a historic cohort of 185 randomly selected patients, who presented to the emergency department with suspectedPE during an eight month period prior to the clinical trial (January 2002 -August 2002 were compared with the number and type of diagnostic tests in745 patients, who presented to the emergency department with suspected PE from November 2002 to August 2003. Current Medicare fees per test were usedas unit costs to calculate the mean aggregated cost of diagnostic investigation per patient in both study groups. A t-test was used to estimate the statistical significance of the difference in the cost of resources used for diagnosing PE in the control and in the intervention group. Results The trial demonstrated that diagnosing PE using an evidence-based clinical protocol was as effective as the existing clinical practice. The clinical protocol offers the advantage of reducing the use of diagnostic imaging, resulting in an average cost savings of at least $59.30 per patient. Conclusion Extrapolating the observed cost-savings of $59.30 per patient to the wholeof Australia could potentially result in annual savings between $3.1 million to $3.7 million.

  6. Periodic driving control of Raman-induced spin-orbit coupling in Bose-Einstein condensates: The heating mechanisms

    Science.gov (United States)

    Gomez Llorente, J. M.; Plata, J.

    2016-06-01

    We focus on a technique recently implemented for controlling the magnitude of synthetic spin-orbit coupling (SOC) in ultracold atoms in the Raman-coupling scenario. This technique uses a periodic modulation of the Raman-coupling amplitude to tune the SOC. Specifically, it has been shown that the effect of a high-frequency sinusoidal modulation of the Raman-laser intensity can be incorporated into the undriven Hamiltonian via effective parameters, whose adiabatic variation can therefore be used to tune the SOC. Here, we characterize the heating mechanisms that can be relevant to this method. We identify the main mechanism responsible for the heating observed in the experiments as basically rooted in driving-induced transfer of population to excited states. Characteristics of that process determined by the harmonic trapping, the decay of the excited states, and the technique used for preparing the system are discussed. Additional heating, rooted in departures from adiabaticity in the variation of the effective parameters, is also described. Our analytical study provides some clues that may be useful in the design of strategies for curbing the effects of heating on the efficiency of the control methods.

  7. TWO NEW LONG-PERIOD HOT SUBDWARF BINARIES WITH DWARF COMPANIONS

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, Brad N.; Wade, Richard A. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Liss, Sandra E. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Green, Elizabeth M., E-mail: bbarlow@psu.edu [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States)

    2013-07-01

    Hot subdwarf stars with F-K main sequence binary companions have been known for decades, but the first orbital periods for such systems were published just recently. Current observations suggest that most have long periods, on the order of years, and that some are or once were hierarchical triple systems. As part of a survey with the Hobby-Eberly Telescope, we have been monitoring the radial velocities of several composite-spectra binaries since 2005 in order to determine their periods, velocities, and eccentricities. Here we present observations and orbital solutions for two of these systems, PG 1449+653 and PG 1701+359. Similar to the other sdB+F/G/K binaries with solved orbits, their periods are long, 909 and 734 days, respectively, and pose a challenge to current binary population synthesis models of hot subdwarf stars. Intrigued by their relatively large systemic velocities, we also present a kinematical analysis of both targets and find that neither is likely a member of the Galactic thin disk.

  8. TWO NEW LONG-PERIOD HOT SUBDWARF BINARIES WITH DWARF COMPANIONS

    International Nuclear Information System (INIS)

    Barlow, Brad N.; Wade, Richard A.; Liss, Sandra E.; Green, Elizabeth M.

    2013-01-01

    Hot subdwarf stars with F-K main sequence binary companions have been known for decades, but the first orbital periods for such systems were published just recently. Current observations suggest that most have long periods, on the order of years, and that some are or once were hierarchical triple systems. As part of a survey with the Hobby-Eberly Telescope, we have been monitoring the radial velocities of several composite-spectra binaries since 2005 in order to determine their periods, velocities, and eccentricities. Here we present observations and orbital solutions for two of these systems, PG 1449+653 and PG 1701+359. Similar to the other sdB+F/G/K binaries with solved orbits, their periods are long, 909 and 734 days, respectively, and pose a challenge to current binary population synthesis models of hot subdwarf stars. Intrigued by their relatively large systemic velocities, we also present a kinematical analysis of both targets and find that neither is likely a member of the Galactic thin disk.

  9. On the Stability of Periodic Mercury-type Rotations

    Science.gov (United States)

    Churkina, Tatyana E.; Stepanov, Sergey Y.

    2017-12-01

    We consider the stability of planar periodic Mercury-type rotations of a rigid body around its center of mass in an elliptical orbit in a central Newtonian field of forces. Mercurytype rotations mean that the body makes 3 turns around its center of mass during 2 revolutions of the center of mass in its orbit (resonance 3:2). These rotations can be 1) symmetrical 2π- periodic, 2) symmetrical 4π-periodic and 3) asymmetrical 4π-periodic. The stability of rotations of type 1) was investigated by A.P.Markeev. In our paper we present a nonlinear stability analysis for some rotations of types 2) and 3) in 3rd- and 4th-order resonant cases, in the nonresonant case and at the boundaries of regions of linear stability.

  10. Lyapunov Orbits in the Jupiter System Using Electrodynamic Tethers

    Science.gov (United States)

    Bokelmann, Kevin; Russell, Ryan P.; Lantoine, Gregory

    2013-01-01

    Various researchers have proposed the use of electrodynamic tethers for power generation and capture from interplanetary transfers. The effect of tether forces on periodic orbits in Jupiter-satellite systems are investigated. A perturbation force is added to the restricted three-body problem model and a series of simplifications allows development of a conservative system that retains the Jacobi integral. Expressions are developed to find modified locations of equilibrium positions. Modified families of Lyapunov orbits are generated as functions of tether size and Jacobi integral. Zero velocity curves and stability analyses are used to evaluate the dynamical properties of tether-modified orbits.

  11. Analytic model for the long-term evolution of circular Earth satellite orbits including lunar node regression

    Science.gov (United States)

    Zhu, Ting-Lei; Zhao, Chang-Yin; Zhang, Ming-Jiang

    2017-04-01

    This paper aims to obtain an analytic approximation to the evolution of circular orbits governed by the Earth's J2 and the luni-solar gravitational perturbations. Assuming that the lunar orbital plane coincides with the ecliptic plane, Allan and Cook (Proc. R. Soc. A, Math. Phys. Eng. Sci. 280(1380):97, 1964) derived an analytic solution to the orbital plane evolution of circular orbits. Using their result as an intermediate solution, we establish an approximate analytic model with lunar orbital inclination and its node regression be taken into account. Finally, an approximate analytic expression is derived, which is accurate compared to the numerical results except for the resonant cases when the period of the reference orbit approximately equals the integer multiples (especially 1 or 2 times) of lunar node regression period.

  12. Right-to-left-shunt detected by c-TCD using the orbital window in comparison with temporal bone windows.

    Science.gov (United States)

    Kobayashi, Kazuto; Kimura, Kazumi; Iguchi, Yasuyuki; Sakai, Kenichirou; Aoki, Junya; Iwanaga, Takeshi; Shibazaki, Kensaku

    2012-01-01

    There have been some reports on right-to-left shunt as a cause of cryptogenic stroke. Although contrast transcranial Doppler (c-TCD) can detect RLS, an insufficient temporal window has occasionally restricted its applicability. Thus, we compared the rates of detecting RLS among temporal windows for the middle cerebral arteries (MCAs) and the orbital window for the internal carotid artery (ICA) on c-TCD. We used c-TCD to detect RLS in patients with suspected ischemic stroke. We enrolled patients who had both sufficient bilateral temporal windows for MCAs and a right orbital window for ICA and performed c-TCD using all three windows simultaneously. We enrolled 106 consecutive patients and identified microembolic signals (MES) in 30 (28%) of them. Among these 30 patients, 15 had MES from all 3 windows. When these 30 patients were defined as being positive for RLS, the rates of detection were 67%, 73%, and 80% from the right temporal, left temporal, and right orbital windows, respectively (P= .795). The right orbital window as well as the temporal window for c-TCD could detect RLS. Insonation from the orbital window should be useful for patients who lack temporal windows. Copyright © 2010 by the American Society of Neuroimaging.

  13. THE FORMATION MECHANISM OF GAS GIANTS ON WIDE ORBITS

    International Nuclear Information System (INIS)

    Dodson-Robinson, Sarah E.; Veras, Dimitri; Ford, Eric B.; Beichman, C. A.

    2009-01-01

    The recent discoveries of massive planets on ultra-wide orbits of HR 8799 and Fomalhaut present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet formation mechanisms-core accretion (with or without migration), scattering from the inner disk, or gravitational instability-could be responsible for Fomalhaut b, HR 8799 b, c and d, and similar planets discovered in the future. This paper presents the results of numerical experiments comparing the long-period planet formation efficiency of each possible mechanism in model A star, G star, and M star disks. First, a simple core accretion simulation shows that planet cores forming beyond 35 AU cannot reach critical mass, even under the most favorable conditions one can construct. Second, a set of N-body simulations demonstrates that planet-planet scattering does not create stable, wide-orbit systems such as HR 8799. Finally, a linear stability analysis verifies previous work showing that global spiral instabilities naturally arise in high-mass disks. We conclude that massive gas giants on stable orbits with semimajor axes a ∼> 35 AU form by gravitational instability in the disk. We recommend that observers examine the planet detection rate as a function of stellar age, controlling for the planets' dimming with time. Any age trend would indicate that planets on wide orbits are transient relics of scattering from the inner disk. If planet detection rate is found to be independent of stellar age, it would confirm our prediction that gravitational instability is the dominant mode of producing detectable planets on wide orbits. We also predict that the occurrence ratio of long-period to short-period gas giants should be highest for M dwarfs due to the inefficiency of core accretion and the expected small fragment mass (∼10 M Jup ) in their disks.

  14. The orbital record in stratigraphy

    Science.gov (United States)

    Fischer, Alfred G.

    1992-01-01

    , and (2) presence of abundant microfossils yields close ties to geochronology. A tantalizing possibility that stratigraphy may yield a record of orbital signals unrelated to climate has turned up in magnetic studies of our Cretaceous core. Magnetic secular variations here carry a strong 39 ka periodicity, corresponding to the theoretical obliquity period of that time - Does the obliquity cycle perhaps have some direct influence on the magnetic field?

  15. Resonant Orbital Dynamics in LEO Region: Space Debris in Focus

    Directory of Open Access Journals (Sweden)

    J. C. Sampaio

    2014-01-01

    Full Text Available The increasing number of objects orbiting the earth justifies the great attention and interest in the observation, spacecraft protection, and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. In this work, objects in resonant orbital motions are studied in low earth orbits. Using the two-line elements (TLE of the NORAD, resonant angles and resonant periods associated with real motions are described, providing more accurate information to develop an analytical model that describes a certain resonance. The time behaviors of the semimajor axis, eccentricity, and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.

  16. Effects of solar radiation on the orbits of small particles

    Science.gov (United States)

    Lyttleton, R. A.

    1976-01-01

    A modification of the Robertson (1937) equations of particle motion in the presence of solar radiation is developed which allows for partial reflection of sunlight as a result of rapid and varying particle rotations caused by interaction with the solar wind. The coefficients and forces in earlier forms of the equations are compared with those in the present equations, and secular rates of change of particle orbital elements are determined. Orbital dimensions are calculated in terms of time, probable sizes and densities of meteoric and cometary particles are estimated, and times of infall to the sun are computed for a particle moving in an almost circular orbit and a particle moving in an elliptical orbit of high eccentricity. Changes in orbital elements are also determined for particles from a long-period sun-grazing comet. The results show that the time of infall to the sun from a highly eccentric orbit is substantially shorter than from a circular orbit with a radius equal to the mean distance in the eccentric orbit. The possibility is considered that the free orbital kinetic energy of particles drawn into the sun may be the energy source for the solar corona.

  17. Orbit monitoring in the SLC

    International Nuclear Information System (INIS)

    Sanchez-Chopitea, L.; Emma, P.; Van Olst, D.

    1991-05-01

    Beam orbits in the SLC are monitored in real time and the data is stored for future trend and correlation analysis. A background process acquires Beam Position Monitor (BPM) and Toroid data on a periodic basis and saves the general quantities such as orbit RMS and beam intensity in addition to the individual readings. Some of this data is archived by the SLC History Buffer facility and the rest is saved in files for later analysis. This has permitted the tracing of interaction point instabilities to specific devices as far away as the damping rings. In addition, the data is displayed for the operators both in summary and in full form. The different displays can be configured from the control consoles. 2 refs., 5 figs

  18. Stabilization of the quasi-periodic motion of a Q-switched Nd:YAG laser

    International Nuclear Information System (INIS)

    Kim, Chil-Min; Rim, Sunghwan; Kye, Won-Ho; Kim, Jeong-Moog; Lee, Kang-Soo

    2004-01-01

    We have developed a stabilization method of quasi-periodicity based on a return map. The method is explained in the forced Van der Pol oscillator, and applied experimentally to a quasi-periodic output of a Q-switched Nd:YAG laser. Even though the attractors have no unstable periodic orbit, we were able to stabilize them to an arbitrarily chosen orbit by targeting the trajectory into it

  19. [Orbital inflammation].

    Science.gov (United States)

    Mouriaux, F; Coffin-Pichonnet, S; Robert, P-Y; Abad, S; Martin-Silva, N

    2014-12-01

    Orbital inflammation is a generic term encompassing inflammatory pathologies affecting all structures within the orbit : anterior (involvement up to the posterior aspect of the globe), diffuse (involvement of intra- and/or extraconal fat), apical (involvement of the posterior orbit), myositis (involvement of only the extraocular muscles), dacryoadenitis (involvement of the lacrimal gland). We distinguish between specific inflammation and non-specific inflammation, commonly referred to as idiopathic inflammation. Specific orbital inflammation corresponds to a secondary localization of a "generalized" disease (systemic or auto-immune). Idiopathic orbital inflammation corresponds to uniquely orbital inflammation without generalized disease, and thus an unknown etiology. At the top of the differential diagnosis for specific or idiopathic orbital inflammation are malignant tumors, represented most commonly in the adult by lympho-proliferative syndromes and metastases. Treatment of specific orbital inflammation begins with treatment of the underlying disease. For idiopathic orbital inflammation, treatment (most often corticosteroids) is indicated above all in cases of visual loss due to optic neuropathy, in the presence of pain or oculomotor palsy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  20. Plasma balance equations based on orbit theory

    International Nuclear Information System (INIS)

    Lehnert, B.

    1982-01-01

    A set of plasma balance equations is proposed which is based on orbit theory and the particle distribution function, to provide means for theoretical analysis of a number of finite Larmor radius (FLR) phenomena without use of the Vlasov equation. Several important FLR effects originate from the inhomogeneity of an electric field in the plasma. The exact solution of a simple case shows that this inhomogeneity introduces fundamental changes in the physics of the particle motion. Thus, the periodic Larmor motion (gyration) is shifted in frequency and becomes elliptically polarized. Further, the non-periodic guiding-centre drift obtains additional components, part of which are accelerated such as to make the drift orbits intersect the equipotential surfaces of a static electric field. An attempt is finally made to classify the FLR effects, also with the purpose of identifying phenomena which have so far not been investigated. (author)

  1. PyORBIT: A Python Shell For ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-07-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.

  2. PyORBIT: A Python Shell For ORBIT

    International Nuclear Information System (INIS)

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-01-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability

  3. Orbital Eccentricity and the Stability of Planets in the Alpha Centauri System

    Science.gov (United States)

    Lissauer, Jack

    2016-01-01

    Planets on initially circular orbits are typically more dynamically stable than planets initially having nonzero eccentricities. However, the presence of a major perturber that forces periodic oscillations of planetary eccentricity can alter this situation. We investigate the dependance of system lifetime on initial eccentricity for planets orbiting one star within the alpha Centauri system. Our results show that initial conditions chosen to minimize free eccentricity can substantially increase stability compared to planets on circular orbits.

  4. Talking heads : interviewing suspects from a cultural perspective

    OpenAIRE

    Beune, K.

    2009-01-01

    Although the literature on the interviewing of suspects has increased over the past decade, research on the use and effectiveness of police strategies and their boundary conditions is very rare. The present dissertation aims to fill this void by identifying behaviors that appeal to and persuade suspects to talk (i.e., influencing behavior), focusing on the effects of such behaviors and their dependency on cultural context (low-context vs. high-context). In doing so, we depart from a theoretic...

  5. A Period Study of the Near Contact Binary EG Cep

    Directory of Open Access Journals (Sweden)

    Chun-Hwey Kim

    2006-06-01

    Full Text Available New eight times of minimum light of the near-contact binary EG Cep were presented. All times of minimum light for EG Cep, including ours, were collected and analyzed to study it's orbital period variation. It was found that the orbital period have varied in a cyclical way superposed on an upward parabola. A secular period increase of 3.22 times 10^{-8} d/y was calculated. Under the assumption of a conservative mass transfer, it implied that the stellar gaseous material of about 3.18 times 10^{-8} rm M_odot /year is transferring from the less massive secondary component to the primary. The cyclical period variation was interpreted as light-time effect due to an unseen third body in the system. The resultant period, semi-amplitude and eccentricity of the light time orbit were calculated to be 38.^{rm y}4, 0.^{rm d}0034 and 0.29, respectively. The mass range of the tertiary proposed in the system is deduced to be quite small as 0.10M_{odot} leq M_3 leq 0.21M_{odot} for i_3 g!

  6. AN EXTENDED AND MORE SENSITIVE SEARCH FOR PERIODICITIES IN ROSSI X-RAY TIMING EXPLORER/ALL-SKY MONITOR X-RAY LIGHT CURVES

    International Nuclear Information System (INIS)

    Levine, Alan M.; Bradt, Hale V.; Chakrabarty, Deepto; Corbet, Robin H. D.; Harris, Robert J.

    2011-01-01

    We present the results of a systematic search in ∼14 years of Rossi X-ray Timing Explorer All-Sky Monitor (ASM) data for evidence of periodicities. Two variations of the commonly used Fourier analysis search method have been employed to significantly improve upon the sensitivity achieved by Wen et al. in 2006, who also searched for periodicities in ASM data. In addition, the present search is comprehensive in terms of sources studied and frequency range covered, and has yielded the detection of the signatures of the orbital periods of eight low-mass X-ray binary systems and of ten high-mass X-ray binaries not listed in the tables of Wen et al. Orbital periods, epochs, signal amplitudes, modulation fractions, and folded light curves are given for each of these systems. Seven of the orbital periods are the most precise reported to date. In the course of this work, the 18.545 day orbital period of IGR J18483-0311 was co-discovered, and the first detections in X-rays were made of the ∼3.9 day orbital period of LMC X-1 and the ∼3.79 hr orbital period of 4U 1636-536. The results inform future searches for orbital and other periodicities in X-ray binaries.

  7. Advanced Earth-to-orbit propulsion technology information, dissemination and research

    Science.gov (United States)

    Wu, S. T.

    1995-01-01

    In this period of performance a conference (The 1994 Conference on Advanced Earth-to-Orbit Propulsion Technology) was organized and implemented by the University of Alabama in Huntsville and held May 15-17 to assemble and disseminate the current information on Advanced Earth-to-Orbit Propulsion Technology. The results were assembled for publication as NASA-CP-3282, Volume 1 and 2 and NASA-CP-3287.

  8. Geosynchronous inclined orbits for high-latitude communications

    Science.gov (United States)

    Fantino, E.; Flores, R. M.; Di Carlo, M.; Di Salvo, A.; Cabot, E.

    2017-11-01

    We present and discuss a solution to the growing demand for satellite telecommunication coverage in the high-latitude geographical regions (beyond 55°N), where the signal from geostationary satellites is limited or unavailable. We focus on the dynamical issues associated to the design, the coverage, the maintenance and the disposal of a set of orbits selected for the purpose. Specifically, we identify a group of highly inclined, moderately eccentric geosynchronous orbits derived from the Tundra orbit (geosynchronous, eccentric and critically inclined). Continuous coverage can be guaranteed by a constellation of three satellites in equally spaced planes and suitably phased. By means of a high-precision model of the terrestrial gravity field and the relevant environmental perturbations, we study the evolution of these orbits. The effects of the different perturbations on the ground track (which is more important for coverage than the orbital elements themselves) are isolated and analyzed. The physical model and the numerical setup are optimized with respect to computing time and accuracy. We show that, in order to maintain the ground track unchanged, the key parameters are the orbital period and the argument of perigee. Furthermore, corrections to the right ascension of the ascending node are needed in order to preserve the relative orientation of the orbital planes. A station-keeping strategy that minimizes propellant consumption is then devised, and comparisons are made between the cost of a solution based on impulsive maneuvers and one with continuous thrust. Finally, the issue of end-of-life disposal is discussed.

  9. Reliability of diagnostic imaging techniques in suspected acute appendicitis: proposed diagnostic protocol

    International Nuclear Information System (INIS)

    Cura del, J. L.; Oleaga, L.; Grande, D.; Vela, A. C.; Ibanez, A. M.

    2001-01-01

    To study the utility of ultrasound and computed tomography (CT) in case of suspected appendicitis. To determine the diagnostic yield in terms of different clinical contexts and patient characteristics. to assess the costs and benefits of introducing these techniques and propose a protocol for their use. Negative appendectomies, complications and length of hospital stay in a group of 152 patients with suspected appendicitis who underwent ultrasound and CT were compared with those of 180 patients who underwent appendectomy during the same time period, but had not been selected for the first group: these patients costs for each group were calculated. In the first group, the diagnostic value of the clinical signs was also evaluated. The reliability of the clinical signs was limited, while the results with ultrasound and CT were excellent. The incidence of negative appendectomy was 9.6% in the study group and 12.2% in the control group. Moreover, there were fewer complications and a shorter hospital stay in the first group. Among men, however, the rate of negative appendectomy was lower in the control group. The cost of using ultrasound and CT in the management of appendicitis was only slightly higher than that of the control group. Although ultrasound and CT are not necessary in cases in which the probability of appendicitis is low or in men presenting clear clinical evidence, the use of these techniques is indicated in the remaining cases in which appendicitis is suspected. In children, ultrasound is the technique of choice. In all other patients, if negative results are obtained with one of the two techniques, the other should be performed. (Author) 49 refs

  10. Orbit Propagation and Determination of Low Earth Orbit Satellites

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2014-01-01

    Full Text Available This paper represents orbit propagation and determination of low Earth orbit (LEO satellites. Satellite global positioning system (GPS configured receiver provides position and velocity measures by navigating filter to get the coordinates of the orbit propagation (OP. The main contradictions in real-time orbit which is determined by the problem are orbit positioning accuracy and the amount of calculating two indicators. This paper is dedicated to solving the problem of tradeoffs. To plan to use a nonlinear filtering method for immediate orbit tasks requires more precise satellite orbit state parameters in a short time. Although the traditional extended Kalman filter (EKF method is widely used, its linear approximation of the drawbacks in dealing with nonlinear problems was especially evident, without compromising Kalman filter (unscented Kalman Filter, UKF. As a new nonlinear estimation method, it is measured at the estimated measurements on more and more applications. This paper will be the first study on UKF microsatellites in LEO orbit in real time, trying to explore the real-time precision orbit determination techniques. Through the preliminary simulation results, they show that, based on orbit mission requirements and conditions using UKF, they can satisfy the positioning accuracy and compute two indicators.

  11. Cranio-orbital approach for complex aneurysmal surgery.

    LENUS (Irish Health Repository)

    Kelleher, M O

    2012-02-03

    Certain aneurysms of the anterior circulation continue to offer a technical challenge for safe exposure and clipping. The purpose of this paper was to describe the cranio-orbital approach for surgical clipping of complex aneurysms and to evaluate prospectively the associated complications of this approach. Prospective audit of all patients undergoing cranio-orbital approach for aneurysm surgery from 1997 to 2004 by the senior author. Twenty-five patients, eight male and 17 female, median age of 52 years, range 28-73. All patients had a standard pterional approach supplemented by an orbital osteotomy. In the 7-year period 367 patients underwent treatment for their aneurysms (169 clipped and 198 coiled). Of the 169 patients who were operated on, 29 had a skull base approach, of which 25 were cranio-orbital. The aneurysm location was as follows: 16 middle cerebral artery (MCA), three carotid bifurcation, four anterior communicating artery (ACOMM), one ophthalmic and one basilar. There were no approach-related complications. The cranio-orbital craniotomy can be a useful adjunct in the surgical treatment of giant or complex aneurysms. It offers the following advantages over a standard pterional approach: reduces operative distance; allows easy splitting of the sylvian fissure; and provides a wide arc of exposure with multiple working corridors.

  12. Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis

    Directory of Open Access Journals (Sweden)

    Sumeet Jain

    2016-01-01

    Full Text Available Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

  13. Central configurations, periodic orbits, and Hamiltonian systems

    CERN Document Server

    Llibre, Jaume; Simó, Carles

    2015-01-01

    The notes of this book originate from three series of lectures given at the Centre de Recerca Matemàtica (CRM) in Barcelona. The first one is dedicated to the study of periodic solutions of autonomous differential systems in Rn via the Averaging Theory and was delivered by Jaume Llibre. The second one, given by Richard Moeckel, focusses on methods for studying Central Configurations. The last one, by Carles Simó, describes the main mechanisms leading to a fairly global description of the dynamics in conservative systems. The book is directed towards graduate students and researchers interested in dynamical systems, in particular in the conservative case, and aims at facilitating the understanding of dynamics of specific models. The results presented and the tools introduced in this book include a large range of applications.

  14. ORBITAL INJURIES

    Directory of Open Access Journals (Sweden)

    Andrej Kansky

    2002-12-01

    Full Text Available Background. Orbit is involved in 40% of all facial fractures. There is considerable variety in severity, ranging from simple nondisplaced to complex comminuted fractures. Complex comminuted fractures (up to 20% are responsible for the majority of complications and unfavorable results. Orbital fractures are classified as internal orbital fractures, zygomatico-orbital fractures, naso-orbito-ethmoidal fractures and combined fractures. The ophtalmic sequelae of midfacial fractures are usually edema and ecchymosis of the soft tissues, subconjuctival hemorrhage, diplopia, iritis, retinal edema, ptosis, enophthalmos, ocular muscle paresis, mechanical restriction of ocular movement and nasolacrimal disturbances. More severe injuries such as optic nerve trauma and retinal detachments have also been reported. Within the wide range of orbital fractures small group of complex fractures causes most of the sequelae. Therefore identification of severe injuries and adequate treatment is of major importance. The introduction of craniofacial techniques made possible a wide exposure even of large orbital wall defects and their reconstruction by bone grafts. In spite of significant progress, repair of complex orbital wall defects remains a problem even for the experienced surgeons.Results. In 1999 121 facial injuries were treated at our department (Clinical Centre Ljubljana Dept. Of Maxillofacial and Oral Surgery. Orbit was involved in 65% of cases. Isolated inner orbital fractures presented 4% of all fractures. 17 (14% complex cases were treated, 5 of them being NOE, 5 orbital (frame and inner walls, 3 zygomatico-orbital, 2 FNO and 2 maxillo-orbital fractures.Conclusions. Final result of the surgical treatment depends on severity of maxillofacial trauma. Complex comminuted fractures are responsable for most of the unfavorable results and ocular function is often permanently damaged (up to 75% in these fractures.

  15. Orbital

    OpenAIRE

    Yourshaw, Matthew Stephen

    2017-01-01

    Orbital is a virtual reality gaming experience designed to explore the use of traditional narrative structure to enhance immersion in virtual reality. The story structure of Orbital was developed based on the developmental steps of 'The Hero's Journey,' a narrative pattern identified by Joseph Campbell. Using this standard narrative pattern, Orbital is capable of immersing the player quickly and completely for the entirety of play time. MFA

  16. Planet X as the source of the periodic and steady-state flux of short period comets

    International Nuclear Information System (INIS)

    Matese, J.J.; Whitmire, D.P.

    1986-01-01

    The cratering and fossil records suggest that impacts on the earth have been modulated with a period of roughly 30 Myr. In the Planet X model, this modulation is the result of the interaction of Planet X with a primordial disk of planetesimals lying beyond the orbit of Neptune. In this paper, observational and theoretical evidence supporting the existence of Planet X and the planetesimal disk is briefly reviewed, and the constraints on the orbit parameters of Planet X and the disk parameters which must be satisfied to ensure consistency with observational limits are discussed

  17. Orbit Functions

    Directory of Open Access Journals (Sweden)

    Anatoliy Klimyk

    2006-01-01

    Full Text Available In the paper, properties of orbit functions are reviewed and further developed. Orbit functions on the Euclidean space E_n are symmetrized exponential functions. The symmetrization is fulfilled by a Weyl group corresponding to a Coxeter-Dynkin diagram. Properties of such functions will be described. An orbit function is the contribution to an irreducible character of a compact semisimple Lie group G of rank n from one of its Weyl group orbits. It is shown that values of orbit functions are repeated on copies of the fundamental domain F of the affine Weyl group (determined by the initial Weyl group in the entire Euclidean space E_n. Orbit functions are solutions of the corresponding Laplace equation in E_n, satisfying the Neumann condition on the boundary of F. Orbit functions determine a symmetrized Fourier transform and a transform on a finite set of points.

  18. Method for detection of a suspect viral deoxyribonucleic acid in an acellular biological fluid

    Energy Technology Data Exchange (ETDEWEB)

    Berninger, M S

    1982-10-06

    A method for evaluating an acellular biological fluid for the presence of a suspect viral DNA, such as DNA of the Hepatitis-B virus, is described. The acellular biological fluid is treated to immobilize in denatured form the DNAs including the suspect viral DNA on a solid substrate. This substrate is contacted with a solution including radioisotopically-labelled suspect viral denatured DNA to renature the immobilized suspect viral native DNA. The solid substrate is then evaluated for radioisotopically-labelled suspect viral renatured DNA.

  19. Solar Radiation Pressure Binning for the Geosynchronous Orbit

    Science.gov (United States)

    Hejduk, M. D.; Ghrist, R. W.

    2011-01-01

    Orbital maintenance parameters for individual satellites or groups of satellites have traditionally been set by examining orbital parameters alone, such as through apogee and perigee height binning; this approach ignored the other factors that governed an individual satellite's susceptibility to non-conservative forces. In the atmospheric drag regime, this problem has been addressed by the introduction of the "energy dissipation rate," a quantity that represents the amount of energy being removed from the orbit; such an approach is able to consider both atmospheric density and satellite frontal area characteristics and thus serve as a mechanism for binning satellites of similar behavior. The geo-synchronous orbit (of broader definition than the geostationary orbit -- here taken to be from 1300 to 1800 minutes in orbital period) is not affected by drag; rather, its principal non-conservative force is that of solar radiation pressure -- the momentum imparted to the satellite by solar radiometric energy. While this perturbation is solved for as part of the orbit determination update, no binning or division scheme, analogous to the drag regime, has been developed for the geo-synchronous orbit. The present analysis has begun such an effort by examining the behavior of geosynchronous rocket bodies and non-stabilized payloads as a function of solar radiation pressure susceptibility. A preliminary examination of binning techniques used in the drag regime gives initial guidance regarding the criteria for useful bin divisions. Applying these criteria to the object type, solar radiation pressure, and resultant state vector accuracy for the analyzed dataset, a single division of "large" satellites into two bins for the purposes of setting related sensor tasking and orbit determination (OD) controls is suggested. When an accompanying analysis of high area-to-mass objects is complete, a full set of binning recommendations for the geosynchronous orbit will be available.

  20. Detection of Rabies antigen in brains of suspected Rabid dogs ...

    African Journals Online (AJOL)

    Objective: To detect the presence of rabies antigen in brains of suspected rabid dogs. Materials and Methods: Ninety six (96) brain specimens from suspected rabid dogs were examined for the presence of rabies antigen using Seller's staining technique and enzyme immunoassay. Results: The two techniques were both ...

  1. Considerations for ultrasonic testing application for on-orbit NDE

    Science.gov (United States)

    Koshti, Ajay M.

    2015-04-01

    The paper addresses some on-orbit nondestructive evaluation (NDE) needs of NASA for International Space Station (ISS). The presentation gives NDE requirements for inspecting suspect damage due to micro-meteoroids and orbital debris (MMOD) impact on the pressure wall of the ISS. This inspection is meant to be conducted from inside of the ISS module. The metallic wall of the module has a fixed wall thickness but also has integral orthogrid ribs for reinforcement. Typically, a single MMOD hit causes localized damage in a small area causing loss of material similar to pitting corrosion, but cracks may be present too. The impact may cause bulging of the wall. Results of the ultrasonic and eddy current demonstration scans on test samples are provided. The ultrasonic technique uses shear wave scans to interrogate the localized damage area from the surrounding undamaged area. The scanning protocol results in multiple scans, each with multiple "vee" paths. A superimposition and mosaic of the three-dimensional ultrasonic data from individual scans is desired to create C-scan images of the damage. This is a new data reduction process which is not currently implemented in state-of-art ultrasonic instruments. Results of ultrasonic scans on the simulated MMOD damage test plates are provided. The individual C-scans are superimposed manually creating mosaic of the inspection. The resulting image is compared with visibly detected damage boundaries, X-ray images, and localized ultrasonic and eddy current scans for locating crack tips to assess effectiveness of the ultrasonic scanning. The paper also discusses developments needed in improving ergonomics of the ultrasonic testing for on-orbit applications.

  2. Method for detection of a suspect viral deoxyribonucleic acid in an acellular biological fluid

    International Nuclear Information System (INIS)

    Berninger, M.S.

    1982-01-01

    A method for evaluating an acellular biological fluid for the presence of a suspect viral DNA, such as DNA of the Hepatitis-B virus, is described. The acellular biological fluid is treated to immobilize in denatured form the DNAs including the suspect viral DNA on a solid substrate. This substrate is contacted with a solution including radioisotopically-labelled suspect viral denatured DNA to renature the immobilized suspect viral native DNA. The solid substrate is then evaluated for radioisotopically-labelled suspect viral renatured DNA. (author)

  3. DISK-PLANETS INTERACTIONS AND THE DIVERSITY OF PERIOD RATIOS IN KEPLER'S MULTI-PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Baruteau, Clement; Papaloizou, John C. B.

    2013-01-01

    The Kepler mission is dramatically increasing the number of planets known in multi-planetary systems. Many adjacent planets have orbital period ratios near resonant values, with a tendency to be larger than required for exact first-order mean-motion resonances. This feature has been shown to be a natural outcome of orbital circularization of resonant planetary pairs due to star-planet tidal interactions. However, this feature holds in multi-planetary systems with periods longer than 10 days, in which tidal circularization is unlikely to provide efficient divergent evolution of the planets' orbits to explain these orbital period ratios. Gravitational interactions between planets and their parent protoplanetary disk may instead provide efficient divergent evolution. For a planet pair embedded in a disk, we show that interactions between a planet and the wake of its companion can reverse convergent migration and significantly increase the period ratio from a near-resonant value. Divergent evolution due to wake-planet interactions is particularly efficient when at least one of the planets opens a partial gap around its orbit. This mechanism could help account for the diversity of period ratios in Kepler's multiple systems from super-Earth to sub-Jovian planets with periods greater than about 10 days. Diversity is also expected for pairs of planets massive enough to merge their gap. The efficiency of wake-planet interactions is then much reduced, but convergent migration may stall with a variety of period ratios depending on the density structure in the common gap. This is illustrated for the Kepler-46 system, for which we reproduce the period ratio of Kepler-46b and c

  4. A Dynamical Systems Approach to the Design of the Science Orbit Around Europa

    Science.gov (United States)

    Gomez, Gerard; Lara, Martin; Russell, Ryan P.

    2006-01-01

    The science orbit for a future mission to Europa requires low eccentricity, low altitude, and high inclination. However, high inclination orbits around planetary satellites are unstable due to third-body perturbations. Without control, the orbiter impacts Europa after few weeks. To minimize control, a tour over the stable-unstable, averaged manifolds of unstable frozen orbits has been suggested. We proceed with the unaveraged equations and study the manifolds of unstable orbits that are periodic in a rotating frame attached to Europa. Massive numerical computation helps in understanding the unstable dynamics close to Europa, and, thus, in selecting long lifetime high inclination orbits. A final test of a selected set of initial conditions on a high fidelity, ephemeris model, validate the results.

  5. Self-reported care needs of Dutch homeless people with and without a suspected intellectual disability: a 1.5-year follow-up study.

    Science.gov (United States)

    Van Straaten, Barbara; Rodenburg, Gerda; Van der Laan, Jorien; Boersma, Sandra N; Wolf, Judith R L M; Van de Mheen, Dike

    2017-01-01

    Cognitive impairment is a prevalent problem among the homeless and seems related to more psychosocial problems. However, little is known about the care needs of the subgroup of homeless people with an intellectual disability compared to those without an intellectual disability and how their care needs develop over time. This study explores self-reported care needs within a broad range of life domains among Dutch homeless people with and without a suspected intellectual disability to gain insight into the transition of self-reported care needs from baseline to follow-up in both subgroups. This longitudinal study is part of a cohort study among homeless people who had been accepted for an individual programme plan in four major Dutch cities. The initial cohort consisted of 513 participants who were interviewed in 2011. At 1.5-year follow-up, 336 participants (65.5%) were also interviewed and screened for intellectual disability. Of these participants, 31% (95% CI 26.2-36.1) had a suspected intellectual disability. For both groups, between baseline and follow-up, the number of 'unmet care needs' decreased significantly and the number of 'no care needs' increased significantly, while at follow-up, participants with a suspected intellectual disability reported 'no care needs' on significantly fewer life domains than those without a suspected intellectual disability (mean numbers 16.4 vs. 17.5). Between baseline and follow-up, 'met care needs' decreased significantly on housing for both groups, and increased on finances and dental care for participants with a suspected intellectual disability. At follow-up, participants with a suspected intellectual disability more often preferred housing support available by appointment than those without a suspected intellectual disability. These findings suggest that homeless people who had been accepted for an individual programme plan with a suspected intellectual disability have care needs for a longer period of time than those

  6. The recent development in understanding the periodic table of elements

    International Nuclear Information System (INIS)

    Niizeki, K.

    1986-01-01

    The recent development in understanding the periodic table of elements is reviewed. The author's concern is focussed on the effects which make different elements of a group of the periodic table to have different chemical properties, which result in that different members of a homologous series of compounds have different physical properties. The most important effect is due to the effective repulsion of the valence orbital of an atom from the core region by orthogonality with the core orbitals with the same azimuthal quantum number

  7. On the Lack of Circumbinary Planets Orbiting Isolated Binary Stars

    Science.gov (United States)

    Fleming, David P.; Barnes, Rory; Graham, David E.; Luger, Rodrigo; Quinn, Thomas R.

    2018-05-01

    We outline a mechanism that explains the observed lack of circumbinary planets (CBPs) via coupled stellar–tidal evolution of isolated binary stars. Tidal forces between low-mass, short-period binary stars on the pre-main sequence slow the stellar rotations transferring rotational angular momentum to the orbit as the stars approach the tidally locked state. This transfer increases the binary orbital period, expanding the region of dynamical instability around the binary, and destabilizing CBPs that tend to preferentially orbit just beyond the initial dynamical stability limit. After the stars tidally lock, we find that angular momentum loss due to magnetic braking can significantly shrink the binary orbit, and hence the region of dynamical stability, over time, impacting where surviving CBPs are observed relative to the boundary. We perform simulations over a wide range of parameter space and find that the expansion of the instability region occurs for most plausible initial conditions and that, in some cases, the stability semimajor axis doubles from its initial value. We examine the dynamical and observable consequences of a CBP falling within the dynamical instability limit by running N-body simulations of circumbinary planetary systems and find that, typically, at least one planet is ejected from the system. We apply our theory to the shortest-period Kepler binary that possesses a CBP, Kepler-47, and find that its existence is consistent with our model. Under conservative assumptions, we find that coupled stellar–tidal evolution of pre-main sequence binary stars removes at least one close-in CBP in 87% of multi-planet circumbinary systems.

  8. A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship

    Science.gov (United States)

    Genova, Anthony L.; Aldrin, Buzz

    2015-01-01

    A periodic circumlunar orbit is presented that can be used by an interplanetary cruise ship for regular travel between Earth and the Moon. This Earth-Moon cycler orbit was revealed by introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month) which yields close-Earth encounters every 7 or 10 days. Lunar encounters occur every 26 days and offer the chance for a smaller craft to depart the cycler and enter lunar orbit, or head for a Lagrange point (e.g., EM-L2 halo orbit), distant retrograde orbit (DRO), or interplanetary destination such as a near-Earth object (NEO) or Mars. Additionally, return-to-Earth abort options are available from many points along the cycling trajectory.

  9. K-theory and periodic cyclic homology of some noncompact quantum algebras

    International Nuclear Information System (INIS)

    Do Ngoc Diep; Kuku, Aderemi O.

    2003-07-01

    We prove in this paper that the periodic cyclic homology of the quantized algebras of functions on coadjoint orbits of connected and simply connected Lie group, are isomorphic to the periodic cyclic homology of the quantized algebras of functions on coadjoint orbits of compact maximal subgroups, without localization. Some noncompact quantum groups and algebras were constructed and their irreducible representations were classified in recent works of Do Ngoc Diep and Nguyen Viet Hai [DH1]-[DH2] and Do Due Hanh [DD] by using deformation quantization. In this paper we compute their K-groups, periodic cyclic homology groups and their Chern characters. (author)

  10. Increasing average period lengths by switching of robust chaos maps in finite precision

    Science.gov (United States)

    Nagaraj, N.; Shastry, M. C.; Vaidya, P. G.

    2008-12-01

    Grebogi, Ott and Yorke (Phys. Rev. A 38, 1988) have investigated the effect of finite precision on average period length of chaotic maps. They showed that the average length of periodic orbits (T) of a dynamical system scales as a function of computer precision (ɛ) and the correlation dimension (d) of the chaotic attractor: T ˜ɛ-d/2. In this work, we are concerned with increasing the average period length which is desirable for chaotic cryptography applications. Our experiments reveal that random and chaotic switching of deterministic chaotic dynamical systems yield higher average length of periodic orbits as compared to simple sequential switching or absence of switching. To illustrate the application of switching, a novel generalization of the Logistic map that exhibits Robust Chaos (absence of attracting periodic orbits) is first introduced. We then propose a pseudo-random number generator based on chaotic switching between Robust Chaos maps which is found to successfully pass stringent statistical tests of randomness.

  11. Radiologic evaluation of orbital index among Ghanaians using CT scan.

    Science.gov (United States)

    Botwe, Benard Ohene; Sule, Derick Seyram; Ismael, Abdul Mumin

    2017-07-11

    Orbital index (OI) expresses the proportion of the orbital height to the orbital width and varies with race, regions within the same race and periods in evolution. This index is useful in forensic medicine, anthropology and surgery. However, the average OI among Ghanaian adults was unknown. The aim of this study was to determine the orbital index of adult Ghanaians and classify them under one of the three predetermined groups. The study design was a retrospective cross-sectional. A systematic random sampling method was used for selecting 350 adult Ghanaian head computed tomography images available from 1 January to 31 December 2015 at KBTH Hospital. The orbital height and orbital width of each orbit were measured on a 3D CT skull. Data was analysed using Microsoft Excel and Statistical Package for Social Sciences version 20. The study had more females than men (167, 47.71%, vs 183, 52.29%). The observed orbital index of Ghanaians in the study was 81.22 ± 4.22. The mean orbital index was 80.52 ± 4.66 in males and 82.15 ± 3.83 in females with their difference being statistically significant (p value forensic medicine for skull classification and also for better surgical approach in neurosurgery as well as cosmetic surgery.

  12. Statistical U-Th dating results of speleothem from south Europe and the orbital-scale implication

    Science.gov (United States)

    Hu, H. M.

    2016-12-01

    Reconstructing of hydroclimate in the Mediterranean on an orbital time scale helps improve our understanding of interaction between orbital forcing and north hemisphere climate. We collected 180 speleothem subsamples from Observatoire Cave (Monaco), Prince Cave (south France), Chateaueuf Cave (South France), Arago Cave (South France), and Basura Cave (North Italy) during 2013 to 2015 C.E. Uranium-thorium dating were conducted in the High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), National Taiwan University. The results show that most of the speleothem formed during interglacial periods, particularly in marine isotope stage (MIS) 1, 5, and 11. However, only a few speleothem were dated between 180 to 250 thousand years ago (ka). The interval is approximately equivalent to MIS 7, which is a period with contrasting orbital parameters compared to MIS1, 5, and 11. Our statistical dating result implies that the orbital-scale humid/dry condition in southern Europe could be dominantly controlled by orbital forcing.

  13. The impact of ultrasound in suspected acute appendicitis

    International Nuclear Information System (INIS)

    Gracey, D.; McClure, M.J.

    2007-01-01

    Aims: To evaluate prospectively the impact of an appendix ultrasound (US) service on the clinical management of patients presenting with suspected acute appendicitis. Materials and methods: The referring clinician completed a proforma for patients presenting with suspected acute appendicitis. Two visual analogue scales assessed clinical suspicion before and after knowledge of laboratory results. The clinician also indicated if they intended to operate had US been unavailable. During a 3-year period, 327 patients were examined by graded-compression US and diagnosed 'positive' or 'negative' for acute appendicitis. Findings were correlated with histopathology results. The referring clinician completed a retrospective audit questionnaire to assess user satisfaction. Results: Clinical suspicion was altered by knowledge of laboratory results. The decision to operate if US had been unavailable, was 'yes' in 70 cases (group A), 'no' in 231 (group B), and incomplete in 26 (group C). In group A, 31 patients (44.3%) had a negative US and 25 avoided surgery. US identified 39 cases of appendicitis and 37 appendicectomies confirmed appendicitis in 34 cases. In group B, 72 (31.2%) patients had a positive US and 66 appendicectomies confirmed 51 cases of appendicitis. The sensitivity of US was 94.7% in group A, 93.3% in group B and 93.8% overall. Specificity was 90.6% in group A, 91.2% in group B and 91.3% overall. US findings were contrary to intended surgical management in 103 cases. Management was altered in 97 cases (32.2%), with a positive outcome in 85 (28.2%). The referrers found US of appendix very useful in planning appropriate management. Conclusion: US of the appendix increases diagnostic accuracy, alters management and is more sensitive and specific than clinical impression, either alone, or in conjunction with laboratory results

  14. Spectroscopic orbit for HDE 245770 A0535+26

    International Nuclear Information System (INIS)

    Hutchings, J.B.

    1984-01-01

    Optical spectroscopic data are examined using the X-ray intensity period of 111 days. Optical and X-ray pulse-timing orbit parameters agree well and indicate an eccentricity of approximately 0.3. Masses of the stars and periastron effects are discussed. 6 references

  15. Present Status and Near Term Activities for the ExoMars Trace Gas Orbiter.

    Science.gov (United States)

    Svedhem, H.; Vago, J. L.

    2017-12-01

    The ExoMars 2016 mission was launched on a Proton rocket from Baikonur, Kazakhstan, on 14 March 2016 and arrived at Mars on 19 October 2016. The spacecraft is now performing aerobraking to reduce its orbital period from initial post-insertion orbital period of one Sol to the final science orbit with a 2 hours period. The orbital inclination will be 74 degrees. During the aerobraking a wealth of data has been acquired on the state of the atmosphere along the tracks between 140km and the lowest altitude at about 105 km. These data are now being analysed and compared with existing models. In average TGO measures a lower atmospheric density than predicted, but the numbers lay within the expected variability. ExoMars is a joint programme of the European Space Agency (ESA) and Roscosmos, Russia. It consists of the ExoMars 2016 mission with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, which carries a lander and a rover. The TGO scientific payload consists of four instruments: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector to search for subsurface hydrogen (as proxy for water ice and hydrated minerals). The launch mass of the TGO was 3700 kg, including fuel. In addition to its scientific measurements TGO will act as a relay orbiter for NASA's landers on Mars and as from 2021 for the ESA-Roscosmos Rover and Surface Station.

  16. Using Internet Artifacts to Profile a Child Pornography Suspect

    OpenAIRE

    Marcus K. Rogers; Kathryn C. Seigfried-Spellar

    2014-01-01

    Digital evidence plays a crucial role in child pornography investigations. However, in the following case study, the authors argue that the behavioral analysis or “profiling” of digital evidence can also play a vital role in child pornography investigations. The following case study assessed the Internet Browsing History (Internet Explorer Bookmarks, Mozilla Bookmarks, and Mozilla History) from a suspected child pornography user’s computer. The suspect in this case claimed to be conducting an...

  17. INFRARED SPECTROSCOPY OF SYMBIOTIC STARS. XI. ORBITS FOR SOUTHERN S-TYPE SYSTEMS: HEN 3-461, SY MUS, HEN 3-828, AND AR PAV

    International Nuclear Information System (INIS)

    Fekel, Francis C.; Hinkle, Kenneth H.; Joyce, Richard R.; Wood, Peter R.

    2017-01-01

    Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest currently known for S-type symbiotic systems. That period is very different from the orbital period proposed previously from its photometric variations. The other three binaries have periods between 600 and 700 day, values that are typical for S-type symbiotic orbits. Basic properties of the M giant components and the distance to each system are determined.

  18. Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method

    Energy Technology Data Exchange (ETDEWEB)

    Usvyat, Denis, E-mail: denis.usvyat@chemie.uni-regensburg.de [Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany)

    2013-11-21

    Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are introduced, restricting the list of the explicitly correlated pairs, as well as occupied, virtual, and auxiliary spaces in the strong orthogonality projector to the pair-specific domains on the basis of spatial proximity of respective orbitals. The 4-index two-electron integrals appearing in the formalism are approximated via the direct-space density fitting technique. In this procedure, the fitting orbital spaces are also restricted to local fit-domains surrounding the fitted densities. The formulation of the method and its implementation exploits the translational symmetry and the site-group symmetries of the WFs. Test calculations are performed on LiH crystal. The results show that the periodic LMP2-F12 method substantially accelerates basis set convergence of the total correlation energy, and even more so the correlation energy differences. The resulting energies are quite insensitive to the resolution-of-the-identity domain sizes and the quality of the auxiliary basis sets. The convergence with the orbital domain size is somewhat slower, but still acceptable. Moreover, inclusion of slightly more diffuse functions, than those usually used in the periodic calculations, improves the convergence of the LMP2-F12 correlation energy with respect to both the size of the PAO-domains and the quality of the orbital basis set. At the same time, the essentially diffuse atomic orbitals from standard molecular basis sets, commonly utilized in molecular MP2-F12 calculations, but problematic in the periodic context, are not necessary for LMP2-F12 treatment of crystals.

  19. On the orbit calculation of visual binaries with a very short arc: application to the PMS binary system, FW Tau AB

    Science.gov (United States)

    Docobo, J. A.; Tamazian, V. S.; Campo, P. P.

    2018-05-01

    In the vast majority of cases when available astrometric measurements of a visual binary cover a very short orbital arc, it is practically impossible to calculate a good quality orbit. It is especially important for systems with pre-main-sequence components where standard mass-spectrum calibrations cannot be applied nor can a dynamical parallax be calculated. We have shown that the analytical method of Docobo allows us to put certain constraints on the most likely orbital solutions, using an available realistic estimate of the global mass of the system. As an example, we studied the interesting PMS binary, FW Tau AB, located in the Taurus-Auriga as well as investigated a range of its possible orbital solutions combined with an assumed distance between 120 and 160 pc. To maintain the total mass of FW Tau AB in a realistic range between 0.2 and 0.6M_{⊙}, minimal orbital periods should begin at 105, 150, 335, and 2300 yr for distances of 120, 130, 140, and 150 pc, respectively (no plausible orbits were found assuming a distance of 160 pc). An original criterion to establish the upper limit of the orbital period is applied. When the position angle in some astrometric measurements was flipped by 180°, orbits with periods close to 45 yr are also plausible. Three example orbits with periods of 44.6, 180, and 310 yr are presented.

  20. ERS orbit control

    Science.gov (United States)

    Rosengren, Mats

    1991-12-01

    The European remote sensing mission orbit control is addressed. For the commissioning phase, the orbit is defined by the following requirements: Sun synchronous, local time of descending node 10:30; three days repeat cycle with 43 orbital revolutions; overhead Venice tower (12.508206 deg east, 45.314222 deg north). The launch, maneuvers for the initial acquisition of the operational orbit, orbit maintenance maneuvers, evaluation of the orbit control, and the drift of the inclination are summarized.

  1. ORBIT II sub-analysis: Impact of impaired renal function following treatment of severely calcified coronary lesions with the Orbital Atherectomy System.

    Science.gov (United States)

    Lee, Michael S; Lee, Arthur C; Shlofmitz, Richard A; Martinsen, Brad J; Hargus, Nick J; Elder, Mahir D; Généreux, Philippe; Chambers, Jeffrey W

    2017-04-01

    To investigate the safety and efficacy of the coronary Orbital Atherectomy System (OAS) to prepare severely calcified lesions for stent deployment in patients grouped by renal function. Percutaneous coronary intervention (PCI) of severely calcified lesions is associated with increased rates of major adverse cardiac events (MACE), including death, myocardial infarction (MI), and target vessel revascularization (TVR) compared with PCI of non-calcified vessels. Patients with chronic kidney disease (CKD) are at increased risk for MACE after PCI. The impact of CKD on coronary orbital atherectomy treatment has not been well characterized. ORBIT II was a prospective, multicenter trial in the U.S., which enrolled 443 patients with severely calcified coronary lesions. The MACE rate was defined as a composite of cardiac death, MI, and target vessel revascularization. Of the 441 patients enrolled with known estimated glomerular filtration rate (eGFR) values at baseline, 333 (75.5%) patients had eGFR renal impairment had a higher MACE rate through one year follow-up due to a higher rate of periprocedural MI. Interestingly, the rates of cardiac death and revascularization through 1-year were similar in patients with eGFR renal impairment and severely calcified coronary lesions. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  2. Preferred Hosts for Short-Period Exoplanets

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    In an effort to learn more about how planets form around their host stars, a team of scientists has analyzed the population of Kepler-discovered exoplanet candidates, looking for trends in where theyre found.Planetary OccurrenceSince its launch in 2009, Kepler has found thousands of candidate exoplanets around a variety of star types. Especially intriguing is the large population of super-Earths and mini-Neptunes planets with masses between that of Earth and Neptune that have short orbital periods. How did they come to exist so close to their host star? Did they form in situ, or migrate inwards, or some combination of both processes?To constrain these formation mechanisms, a team of scientists led by Gijs Mulders (University of Arizona and NASAs NExSS coalition) analyzed the population of Kepler planet candidates that have orbital periods between 2 and 50 days.Mulders and collaborators used statistical reconstructions to find the average number of planets, within this orbital range, around each star in the Kepler field. They then determined how this planet occurrence rate changed for different spectral types and therefore the masses of the host stars: do low-mass M-dwarf stars host more or fewer planets than higher-mass, main-sequence F, G, or K stars?Challenging ModelsAuthors estimates for the occurrence rate for short-period planets of different radii around M-dwarfs (purple) and around F, G, and K-type stars (blue). [Mulders et al. 2015]The team found that M dwarfs, compared to F, G, or K stars, host about half as many large planets with orbital periods of P 50 days. But, surprisingly, they host significantly more small planets, racking up an average of 3.5 times the number of planets in the size range of 12.8 Earth-radii.Could it be that M dwarfs have a lower total mass of planets, but that mass is distributed into more, smaller planets? Apparently not: the authors show that the mass of heavy elements trapped in short-orbital-period planets is higher for M

  3. The Shetland Islands scrapie monitoring and control programme: analysis of the clinical data collected from 772 scrapie suspects 1985-1997.

    Science.gov (United States)

    Cockcroft, P D; Clark, A M

    2006-02-01

    There were 574 scrapie positive suspects (histopathological scrapie lesions present) and 198 scrapie negative suspects (histopathological scrapie lesions absent). The greatest number of scrapie cases were recorded in sheep of 2, 3 and 4 years of age which represented 17%, 36% and 23% of the scrapie positive suspects, respectively. The sign sensitivities and specificities for the ten recorded signs were, respectively: pruritus (62%, 42%), ataxia (23%, 74%), hyperaesthesia (32%, 74%), wool loss (25%, 73%), fleece discolouration (29%, 85%), bruxism (23%, 69%), nibbling reflex (17%, 58%), head rubbing (47%, 78%), poll rubbing (25%, 83%). These single signs had poor discriminatory values with likelihood ratios close to one (range 0.89-1.21); combinations of the four signs, pruritus, wool loss, ataxia, hyperaesthesia and emaciation were more discriminatory (range 0.30-4.3). This study covered a time period when bovine spongiform encephalopathy (BSE) might have been introduced into the sheep population on the Shetland Islands via contaminated feed. No temporal changes could be detected in the age structure of the affected animals.

  4. Prime Suspect, Second Row Center

    Science.gov (United States)

    Laird, Ellen A.

    2011-01-01

    His father had been hacked to death in his own bed with an ax the previous November. His mother was similarly brutalized and left for dead with her husband but survived. On the last Monday of that August, after several months and many investigative twists, turns, and fumbles, there sat the son--the prime suspect--in Ellen Laird's literature class,…

  5. Deadly Sunflower Orbits

    Science.gov (United States)

    Hamilton, Douglas P.

    2018-04-01

    Solar radiation pressure is usually very effective at removing hazardous millimeter-sized debris from distant orbits around asteroidsand other small solar system bodies (Hamilton and Burns 1992). Theprimary loss mechanism, driven by the azimuthal component of radiationpressure, is eccentricity growth followed by a forced collision withthe central body. One large class of orbits, however, neatly sidestepsthis fate. Orbits oriented nearly perpendicular to the solar directioncan maintain their face-on geometry, oscillating slowly around a stableequilibrium orbit. These orbits, designated sunflower orbits, arerelated to terminator orbits studied by spacecraft mission designers(Broschart etal. 2014).Destabilization of sunflower orbits occurs only for particles smallenough that radiation pressure is some tens of percent the strength ofthe central body's direct gravity. This greatly enhanced stability,which follows from the inability of radiation incident normal to theorbit to efficiently drive eccentricities, presents a threat tospacecraft missions, as numerous dangerous projectiles are potentiallyretained in orbit. We have investigated sunflower orbits insupport of the New Horizons, Aida, and Lucy missions and find thatthese orbits are stable for hazardous particle sizes at asteroids,comets, and Kuiper belt objects of differing dimensions. Weinvestigate the sources and sinks for debris that might populate suchorbits, estimate timescales and equilibrium populations, and willreport on our findings.

  6. Symmetric periodic orbits near a heteroclinic loop formed by two singular points and their invariant manifolds of dimension 1 and 2

    International Nuclear Information System (INIS)

    Corbera, Montserrat; Llibre, Jaume; Perez-Chavela, Ernesto

    2006-01-01

    In this paper we consider vector fields in R 3 that are invariant under a suitable symmetry and that possess a 'generalized heteroclinic loop' L formed by two singular points (e + and e - ) and their invariant manifolds: one of dimension 2 (a sphere minus the points e + and e - ) and one of dimension 1 (the open diameter of the sphere having endpoints e + and e - ). In particular, we analyse the dynamics of the vector field near the heteroclinic loop L by means of a convenient Poincar? map, and we prove the existence of infinitely many symmetric periodic orbits near L. We also study two families of vector fields satisfying this dynamics. The first one is a class of quadratic polynomial vector fields in R 3 , and the second one is the charged rhomboidal four-body problem

  7. Patch testing in Israeli children with suspected allergic contact dermatitis: A retrospective study and literature review.

    Science.gov (United States)

    Zafrir, Yaron; Trattner, Akiva; Hodak, Emmillia; Eldar, Oren; Lapidoth, Moshe; Ben Amitai, Dan

    2018-01-01

    Childhood allergic contact dermatitis is recognized as a significant clinical problem. The objective was to evaluate the rate of positive patch tests in Israeli children with clinically suspected allergic contact dermatitis, identify possible sex and age differences, compare results with those in Israeli adults, and review pediatric studies in the literature. The study sample included 343 children and adolescents (197 female, 146 male; 1-18 years of age, mean age 11.8 years) with clinically suspected allergic contact dermatitis who underwent patch testing with a standard pediatric series of 23 allergens at a tertiary medical center from 1999 to 2012. Data on clinical characteristics and test results were collected retrospectively from the medical files. Ninety-eight subjects (28.6%) (75 girls [38.1%], 23 boys [15.8%]) had at least one positive reaction. The most frequent reactions were to nickel sulfate, followed by potassium dichromate and cobalt chloride. Nickel sulfate sensitivity was more common in girls, especially those younger than 3 years and older than 12 years. The prevalence of contact sensitization was similar in subjects with and without atopic dermatitis (50% and 51%, respectively). Nickel is the most common allergen in Israeli children, especially girls. Patch testing should be performed in children with clinically suspected allergic contact dermatitis regardless of atopic background. © 2017 Wiley Periodicals, Inc.

  8. Chaotic orbits of a pendulum with variable length

    Directory of Open Access Journals (Sweden)

    Massimo Furi

    2004-03-01

    Full Text Available The main purpose of this investigation is to show that a pendulum, whose pivot oscillates vertically in a periodic fashion, has uncountably many chaotic orbits. The attribute chaotic is given according to the criterion we now describe. First, we associate to any orbit a finite or infinite sequence as follows. We write 1 or $-1$ every time the pendulum crosses the position of unstable equilibrium with positive (counterclockwise or negative (clockwise velocity, respectively. We write 0 whenever we find a pair of consecutive zero's of the velocity separated only by a crossing of the stable equilibrium, and with the understanding that different pairs cannot share a common time of zero velocity. Finally, the symbol $omega$, that is used only as the ending symbol of a finite sequence, indicates that the orbit tends asymptotically to the position of unstable equilibrium. Every infinite sequence of the three symbols ${1,-1,0}$ represents a real number of the interval $[0,1]$ written in base 3 when $-1$ is replaced with 2. An orbit is considered chaotic whenever the associated sequence of the three symbols ${1,2,0}$ is an irrational number of $[0,1]$. Our main goal is to show that there are uncountably many orbits of this type.

  9. ASSESSING THE INFLUENCE OF THE SOLAR ORBIT ON TERRESTRIAL BIODIVERSITY

    International Nuclear Information System (INIS)

    Feng, F.; Bailer-Jones, C. A. L.

    2013-01-01

    The terrestrial record shows a significant variation in the extinction and origination rates of species during the past half-billion years. Numerous studies have claimed an association between this variation and the motion of the Sun around the Galaxy, invoking the modulation of cosmic rays, gamma rays, and comet impact frequency as a cause of this biodiversity variation. However, some of these studies exhibit methodological problems, or were based on coarse assumptions (such as a strict periodicity of the solar orbit). Here we investigate this link in more detail, using a model of the Galaxy to reconstruct the solar orbit and thus a predictive model of the temporal variation of the extinction rate due to astronomical mechanisms. We compare these predictions as well as those of various reference models with paleontological data. Our approach involves Bayesian model comparison, which takes into account the uncertainties in the paleontological data as well as the distribution of solar orbits consistent with the uncertainties in the astronomical data. We find that various versions of the orbital model are not favored beyond simpler reference models. In particular, the distribution of mass extinction events can be explained just as well by a uniform random distribution as by any other model tested. Although our negative results on the orbital model are robust to changes in the Galaxy model, the Sun's coordinates, and the errors in the data, we also find that it would be very difficult to positively identify the orbital model even if it were the true one. (In contrast, we do find evidence against simpler periodic models.) Thus, while we cannot rule out there being some connection between solar motion and biodiversity variations on the Earth, we conclude that it is difficult to give convincing positive conclusions of such a connection using current data.

  10. Orbits

    CERN Document Server

    Xu, Guochang

    2008-01-01

    This is the first book of the satellite era which describes orbit theory with analytical solutions of the second order with respect to all possible disturbances. Based on such theory, the algorithms of orbits determination are completely revolutionized.

  11. RAPID ORBITAL DECAY IN THE 12.75-MINUTE BINARY WHITE DWARF J0651+2844

    Energy Technology Data Exchange (ETDEWEB)

    Hermes, J. J.; Winget, D. E. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Kilic, Mukremin; Gianninas, A.; Kenyon, Scott J. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Brown, Warren R. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Allende Prieto, Carlos; Cabrera-Lavers, Antonio [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Mukadam, Anjum S., E-mail: jjhermes@astro.as.utexas.edu [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)

    2012-10-01

    We report the detection of orbital decay in the 12.75-minute, detached binary white dwarf (WD) SDSS J065133.338+284423.37 (hereafter J0651). Our photometric observations over a 13 month baseline constrain the orbital period to 765.206543(55) s and indicate that the orbit is decreasing at a rate of (- 9.8 {+-} 2.8) Multiplication-Sign 10{sup -12} s s{sup -1} (or -0.31 {+-} 0.09 ms yr{sup -1}). We revise the system parameters based on our new photometric and spectroscopic observations: J0651 contains two WDs with M{sub 1} = 0.26 {+-} 0.04 M{sub Sun} and M{sub 2} = 0.50 {+-} 0.04 M{sub Sun }. General relativity predicts orbital decay due to gravitational wave radiation of (- 8.2 {+-} 1.7) Multiplication-Sign 10{sup -12} s s{sup -1} (or -0.26 {+-} 0.05 ms yr{sup -1}). Our observed rate of orbital decay is consistent with this expectation. J0651 is currently the second-loudest gravitational wave source known in the milli-Hertz range and the loudest non-interacting binary, which makes it an excellent verification source for future missions aimed at directly detecting gravitational waves. Our work establishes the feasibility of monitoring this system's orbital period decay at optical wavelengths.

  12. ARE TIDAL EFFECTS RESPONSIBLE FOR EXOPLANETARY SPIN–ORBIT ALIGNMENT?

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gongjie [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States); Winn, Joshua N., E-mail: gli@cfa.harvard.edu [Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-02-10

    The obliquities of planet-hosting stars are clues about the formation of planetary systems. Previous observations led to the hypothesis that for close-in giant planets, spin–orbit alignment is enforced by tidal interactions. Here, we examine two problems with this hypothesis. First, Mazeh and coworkers recently used a new technique—based on the amplitude of starspot-induced photometric variability—to conclude that spin–orbit alignment is common even for relatively long-period planets, which would not be expected if tides were responsible. We re-examine the data and find a statistically significant correlation between photometric variability and planetary orbital period that is qualitatively consistent with tidal interactions. However it is still difficult to explain quantitatively, as it would require tides to be effective for periods as long as tens of days. Second, Rogers and Lin argued against a particular theory for tidal re-alignment by showing that initially retrograde systems would fail to be re-aligned, in contradiction with the observed prevalence of prograde systems. We investigate a simple model that overcomes this problem by taking into account the dissipation of inertial waves and the equilibrium tide, as well as magnetic braking. We identify a region of parameter space where re-alignment can be achieved, but it only works for close-in giant planets, and requires some fine tuning. Thus, while we find both problems to be more nuanced than they first appeared, the tidal model still has serious shortcomings.

  13. Further Evidence of a Brown Dwarf Orbiting the Post-Common Envelope Eclipsing Binary V470 Cam (HS 0705+6700

    Directory of Open Access Journals (Sweden)

    Bogensberger David

    2017-12-01

    Full Text Available Several post-common envelope binaries have slightly increasing, decreasing or oscillating orbital periods. One of several possible explanations is light travel-time changes, caused by the binary centre-of-mass being perturbed by the gravitational pull of a third body. Further studies are necessary because it is not clear how a third body could have survived subdwarf progenitor mass-loss at the tip of the Red Giant Branch, or formed subsequently. Thirty-nine primary eclipse times for V470 Cam were secured with the Philip Wetton Telescope during the period 2016 November 25th to 2017 January 27th. Available eclipse timings suggest a brown dwarf tertiary having a mass of at least 0.0236(40 M⊙, an elliptical orbit with an eccentricity of 0.376(98 and an orbital period of 11.77(67 years about the binary centreof- mass. The mass and orbit suggest a hybrid formation, in which some ejected material from the subdwarf progenitor was accreted on to a precursor tertiary component, although additional observations would be needed to confirm this interpretation and investigate other possible origins for the binary orbital period change.

  14. Unfair lineups make witnesses more likely to confuse innocent and guilty suspects

    OpenAIRE

    Colloff, Melissa F.; Wade, Kimberley A.; Strange, D.

    2016-01-01

    Eyewitness-identification studies have focused on the idea that unfair lineups (i.e., ones in which the police suspect stands out) make witnesses more willing to identify the police suspect. We examined whether unfair lineups also influence subjects’ ability to distinguish between innocent and guilty suspects and their ability to judge the accuracy of their identification. In a single experiment (N = 8,925), we compared three fair-lineup techniques used by the police with unfair lineups in wh...

  15. Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Staykov, Kalin V., E-mail: kstaykov@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Doneva, Daniela D., E-mail: daniela.doneva@uni-tuebingen.de [Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany); INRNE-Bulgarian Academy of Sciences, 1784, Sofia (Bulgaria); Yazadjiev, Stoytcho S., E-mail: yazad@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany)

    2015-12-21

    According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories.

  16. Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Staykov, Kalin V. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Doneva, Daniela D. [Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany); INRNE-Bulgarian Academy of Sciences, Sofia (Bulgaria); Yazadjiev, Stoytcho S. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany)

    2015-12-15

    According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories. (orig.)

  17. Orbital Chondroma: A rare mesenchymal tumor of orbit

    Directory of Open Access Journals (Sweden)

    Ruchi S Kabra

    2015-01-01

    Full Text Available While relatively common in the skeletal system, cartilaginous tumors are rarely seen originating from the orbit. Here, we report a rare case of an orbital chondroma. A 27-year-old male patient presented with a painless hard mass in the superonasal quadrant (SNQ of left orbit since 3 months. On examination, best-corrected visual acuity of both eyes was 20/20, with normal anterior and posterior segment with full movements of eyeballs and normal intraocular pressure. Computerized tomography scan revealed well defined soft tissue density lesion in SNQ of left orbit. Patient was operated for anteromedial orbitotomy under general anesthesia. Mass was excised intact and sent for histopathological examination (HPE. HPE report showed lobular aggregates of benign cartilaginous cells with mild atypia suggesting of benign cartilaginous tumor - chondroma. Very few cases of orbital chondroma have been reported in literature so far.

  18. The validity of the PAM-RL device for evaluating periodic limb movements in sleep and an investigation on night-to-night variability of periodic limb movements during sleep in patients with restless legs syndrome or periodic limb movement disorder using this system.

    Science.gov (United States)

    Kobayashi, Mina; Namba, Kazuyoshi; Ito, Eiki; Nishida, Shingo; Nakamura, Masaki; Ueki, Yoichiro; Furudate, Naomichi; Kagimura, Tatsuo; Usui, Akira; Inoue, Yuichi

    2014-01-01

    The status of night-to-night variability for periodic limb movements in sleep (PLMS) has not been clarified. With this in mind, we investigated the validity of PLMS measurement by actigraphy with the PAM-RL device in Japanese patients with suspected restless legs syndrome (RLS) or periodic limb movement disorder (PLMD) and the night-to-night variability of PLMS among the subjects. Forty-one subjects (mean age, 52.1±16.1 years) underwent polysomnography (PSG) and PAM-RL measurement simultaneously. Thereafter, subjects used the PAM-RL at home on four more consecutive nights. The correlation between PLMS index on PSG (PLMSI-PSG) and PLM index on PAM-RL (PLMI-PAM) was 0.781 (PPAM-RL. PAM-RL is thought to be valuable for assessing PLMS even in Japanese subjects. Recording of PAM-RL for three or more consecutive nights may be required to ensure the screening reliability of a patient with suspected pathologically frequent PLMS. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Discovery and Orbital Determination of the Transient X-Ray Pulsar GRO J1750-27

    Science.gov (United States)

    Scott, D. M.; Finger, M. H.; Wilson, R. B.; Koh, D. T.; Prince, T. A.; Vaughan, B. A.; Chakrabarty, D.

    1997-01-01

    We report on the discovery and hard X-ray (20 - 70 keV) observations of the 4.45 s period transient X-ray pulsar GRO J1750-27 with the BATSE all-sky monitor on board CGRO. A relatively faint out- burst (less than 30 mcrab peak) lasting at least 60 days was observed during which the spin-up rate peaked at 38 pHz/s and was correlated with the pulsed intensity. An orbit with a period of 29.8 days was found. The large spin-up rate, spin period, and orbital period together suggest that accretion is occurring from a disk and that the outburst is a "giant" outburst typical of a Be/X-ray transient system. No optical counterpart has yet been reported.

  20. Magnetic resonance angiography in suspected cerebral vasculitis

    International Nuclear Information System (INIS)

    Demaerel, Philippe; De Ruyter, Nele; Wilms, Guido; Maes, Frederik; Velghe, Beatrijs

    2004-01-01

    The purpose of this study was to determine the technical capacity and diagnostic accuracy of 3D time-of-flight magnetic resonance angiography (MRA) in suspected cerebral vasculitis in a retrospective analysis of MRA and digital subtraction angiography (DSA) in 14 young patients with clinical and/or radiological suspicion of cerebral vasculitis. A total of nine arteries were evaluated in each patient. Consensus review of DSA by three observers was the reference standard. The sensitivity for detecting a stenosis varied from 62 to 79% for MRA and from 76 to 94% for DSA, depending on the observer. The specificity for detecting a stenosis varied from 83 to 87% for MRA and from 83 to 97% for DSA. Using the criterion ''more than two stenoses in at least two separate vascular distributions'' to consider the examination as being true positive, the false-positive rates for MRA and DSA were comparable. MRA plays a role as the first angiographical examination in the diagnostic work-up of suspected cerebral vasculitis. When more than two stenoses in at least two separate vascular distributions are depicted on MRA, DSA is not expected to add a significant diagnostic contribution in a patient with suspected cerebral vasculitis. DSA remains necessary when MRA is normal or when less than three stenoses are seen. (orig.)

  1. Magnetic resonance angiography in suspected cerebral vasculitis

    Energy Technology Data Exchange (ETDEWEB)

    Demaerel, Philippe; De Ruyter, Nele; Wilms, Guido [Department of Radiology, Universitair Ziekenhuis, KU Leuven, 3000, Leuven (Belgium); Maes, Frederik [Department of Medical Imaging Computing, Universitair Ziekenhuis, KU Leuven, 3000, Leuven (Belgium); Velghe, Beatrijs [Department of Radiology, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600, Genk (Belgium)

    2004-06-01

    The purpose of this study was to determine the technical capacity and diagnostic accuracy of 3D time-of-flight magnetic resonance angiography (MRA) in suspected cerebral vasculitis in a retrospective analysis of MRA and digital subtraction angiography (DSA) in 14 young patients with clinical and/or radiological suspicion of cerebral vasculitis. A total of nine arteries were evaluated in each patient. Consensus review of DSA by three observers was the reference standard. The sensitivity for detecting a stenosis varied from 62 to 79% for MRA and from 76 to 94% for DSA, depending on the observer. The specificity for detecting a stenosis varied from 83 to 87% for MRA and from 83 to 97% for DSA. Using the criterion ''more than two stenoses in at least two separate vascular distributions'' to consider the examination as being true positive, the false-positive rates for MRA and DSA were comparable. MRA plays a role as the first angiographical examination in the diagnostic work-up of suspected cerebral vasculitis. When more than two stenoses in at least two separate vascular distributions are depicted on MRA, DSA is not expected to add a significant diagnostic contribution in a patient with suspected cerebral vasculitis. DSA remains necessary when MRA is normal or when less than three stenoses are seen. (orig.)

  2. Calculation of photoionization differential cross sections using complex Gauss-type orbitals.

    Science.gov (United States)

    Matsuzaki, Rei; Yabushita, Satoshi

    2017-09-05

    Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss-type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so-called two-potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth-order final continuum state and the first-order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss-type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular-frame photoelectron angular distributions of H2+ and H2 . In the calculations of H2 , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. Detecting unstable periodic orbits of nonlinear mappings by a novel quantum-behaved particle swarm optimization non-Lyapunov way

    International Nuclear Information System (INIS)

    Gao Fei; Gao Hongrui; Li Zhuoqiu; Tong Hengqing; Lee, Ju-Jang

    2009-01-01

    It is well known that set of unstable periodic orbits (UPOs) can be thought of as the skeleton for the dynamics. However, detecting UPOs of nonlinear map is one of the most challenging problems of nonlinear science in both numerical computations and experimental measures. In this paper, a new method is proposed to detect the UPOs in a non-Lyapunov way. Firstly three special techniques are added to quantum-behaved particle swarm optimization (QPSO), a novel mbest particle, contracting the searching space self-adaptively and boundaries restriction (NCB), then the new method NCB-QPSO is proposed. It can maintain an effective search mechanism with fine equilibrium between exploitation and exploration. Secondly, the problems of detecting the UPOs are converted into a non-negative functions' minimization through a proper translation in a non-Lyapunov way. Thirdly the simulations to 6 benchmark optimization problems and different high order UPOs of 5 classic nonlinear maps are done by the proposed method. And the results show that NCB-QPSO is a successful method in detecting the UPOs, and it has the advantages of fast convergence, high precision and robustness.

  4. TRMM On-Orbit Performance Reassessed After Control Change

    Science.gov (United States)

    Bilanow, Stephen

    2006-01-01

    data. After the orbit boost, the attitude errors shown by the PR roll have a smooth sine-wave type signal because of the way that attitude errors propagate with the use of gyro data. Yaw errors couple at orbit period to roll with 1/4 orbit lag. By tracking the amplitude, phase, and bias of the sinusoidal PR roll error signal, it was shown that the average pitch rotation axis tends to be offset from orbit normal in a direction perpendicular to the Sun direction, as shown in Figure 2 for a 200 day period following the orbit boost. This is a result of the higher accuracy and stability of the Sun sensor measurements relative to the magnetometer measurements used in the Kalman filter. In November, 2001 a magnetometer calibration adjustment was uploaded which improved the pointing performance, keeping the roll and yaw amplitudes within about 0.1 degrees.

  5. Clinical value of FDG-PET/CT in suspected paraneoplastic syndromes: a retrospective analysis of 137 patients

    Energy Technology Data Exchange (ETDEWEB)

    Bjoern Kristensen, Stine; Hess, Soeren; Petersen, Henrik; Hoeilund-Carlsen, Poul Flemming [Odense University Hospital, Department of Nuclear Medicine, Odense (Denmark)

    2015-12-15

    Paraneoplastic syndromes (PNS) are relatively infrequent manifestations appearing before or after a cancer declares itself. Autoimmune mechanisms may be involved, but their cause and pathogenesis are often unknown. Due to disparity of symptoms, PNS remain a major diagnostic challenge. We examined the value of FDG-PET/CT for ruling in or out malignancy in a heterogeneous group of patients with suspected PNS. We retrospectively extracted data from all patients referred 2009-2013 with suspected PNS. Data included age, sex, follow-up period, scan report, further diagnostic procedures, and final clinical diagnosis. Conclusions of the scan reports were compared to the final follow-up outcome as determined during an average follow-up of 31 months (range 6-51.5) in patients who were not diagnosed with cancer in immediate continuation of a positive PET/CT scan. A total of 137 patients were included. Main causes for referral were neurological (n = 67), rheumatological (n = 25), dermatological (n = 18), nephrological (n = 6), haematological (n = 2), abnormal biochemistry (n = 11), and others (n = 8). The cancer prevalence was 8.8 %. The FDG-PET/CT results were as follows: nine true positives, 22 false positives, 103 true negatives, and three false negatives. Corresponding diagnostic values were: sensitivity 75 %, specificity 82 %, accuracy 82 %, and positive and negative predictive values of 29 % and 97 %, respectively. FDG-PET/CT has in patients with suspected PNS an impressively high negative predictive value and may be of value in ruling out PNS, the more so, the more the number of false positives can be minimized or used in differential diagnosis. We believe that FDG-PET/CT may become an important adjunct to the work-up and triage of patients with suspected PNS. (orig.)

  6. THE 2011 ERUPTION OF THE RECURRENT NOVA T PYXIDIS: THE DISCOVERY, THE PRE-ERUPTION RISE, THE PRE-ERUPTION ORBITAL PERIOD, AND THE REASON FOR THE LONG DELAY

    International Nuclear Information System (INIS)

    Schaefer, Bradley E.; Landolt, Arlo U.; Linnolt, Michael; Stubbings, Rod; Pojmanski, Grzegorz; Plummer, Alan; Kerr, Stephen; Nelson, Peter; Carstens, Rolf; Streamer, Margaret; Richards, Tom; Myers, Gordon; Dillon, William G.

    2013-01-01

    We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day –1 , while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/ P-dot =+313,000 yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 ± 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) × 10 –7 M ☉ yr –1 . We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 ± 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f ν ∝ν 1.0 , although the narrow ultraviolet region has a tilt with a fit of f ν ∝ν 1/3 . We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal source. We confirm the extinction measure from IUE with E(B – V) = 0.25 ± 0.02 mag

  7. THE 2011 ERUPTION OF THE RECURRENT NOVA T PYXIDIS: THE DISCOVERY, THE PRE-ERUPTION RISE, THE PRE-ERUPTION ORBITAL PERIOD, AND THE REASON FOR THE LONG DELAY

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Bradley E.; Landolt, Arlo U. [Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Linnolt, Michael [American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138 (United States); Stubbings, Rod [Tetoora Observatory, Tetoora Road, Victoria (Australia); Pojmanski, Grzegorz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Plummer, Alan [Variable Stars South, Linden Observatory, 105 Glossop Road, Linden, NSW (Australia); Kerr, Stephen [American Association of Variable Star Observers, Variable Stars South, Astronomical Association of Queensland, 22 Green Avenue, Glenlee, Queensland (Australia); Nelson, Peter [Ellinbank Observatory, 1105 Hazeldean Road, Ellinbank 3821, Victoria (Australia); Carstens, Rolf [American Association of Variable Star Observers, Variable Stars South, CBA, Geyserland Observatory, 120 Homedale Street, Rotorua 3015 (New Zealand); Streamer, Margaret [Lexy' s Palace Observatory, 3 Lupin Place, Murrumbateman, NSW (Australia); Richards, Tom [Variable Stars South, Pretty Hill Observatory, P.O. Box 323, Kangaroo Ground 3097, Victoria (Australia); Myers, Gordon [Center for Backyard Astrophysics, Columbia University, 538 West 120th Street, New York, NY 10027 (United States); Dillon, William G. [American Association of Variable Star Observers, 4703 Birkenhead Circle, Missouri City, TX 77459 (United States)

    2013-08-10

    We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day{sup -1}, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/ P-dot =+313,000 yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 {+-} 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1}. We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 {+-} 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f{sub {nu}}{proportional_to}{nu}{sup 1.0}, although the narrow ultraviolet region has a tilt with a fit of f{sub {nu}}{proportional_to}{nu}{sup 1/3}. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal

  8. The 2011 Eruption of the Recurrent Nova T Pyxidis: The Discovery, the Pre-eruption Rise, the Pre-eruption Orbital Period, and the Reason for the Long Delay

    Science.gov (United States)

    Schaefer, Bradley E.; Landolt, Arlo U.; Linnolt, Michael; Stubbings, Rod; Pojmanski, Grzegorz; Plummer, Alan; Kerr, Stephen; Nelson, Peter; Carstens, Rolf; Streamer, Margaret; Richards, Tom; Myers, Gordon; Dillon, William G.

    2013-08-01

    We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day-1, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/\\dot{P}=+313{,000} yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 ± 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) × 10-7 M ⊙ yr-1. We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 ± 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f νvpropν1.0, although the narrow ultraviolet region has a tilt with a fit of f νvpropν1/3. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal source. We confirm the extinction measure from IUE with E(B - V) = 0.25 ± 0.02 mag.

  9. Trapped Proton Environment in Medium-Earth Orbit (2000-2010)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yue [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Friedel, Reinhard Hans [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kippen, Richard Marc [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-31

    This report describes the method used to derive fluxes of the trapped proton belt along the GPS orbit (i.e., a Medium-Earth Orbit) during 2000 – 2010, a period almost covering a solar cycle. This method utilizes a newly developed empirical proton radiation-belt model, with the model output scaled by GPS in-situ measurements, to generate proton fluxes that cover a wide range of energies (50keV- 6MeV) and keep temporal features as well. The new proton radiation-belt model is developed based upon CEPPAD proton measurements from the Polar mission (1996 – 2007). Comparing to the de-facto standard empirical model of AP8, this model is not only based upon a new data set representative of the proton belt during the same period covered by GPS, but can also provide statistical information of flux values such as worst cases and occurrence percentiles instead of solely the mean values. The comparison shows quite different results from the two models and suggests that the commonly accepted error factor of 2 on the AP8 flux output over-simplifies and thus underestimates variations of the proton belt. Output fluxes from this new model along the GPS orbit are further scaled by the ns41 in-situ data so as to reflect the dynamic nature of protons in the outer radiation belt at geomagnetically active times. Derived daily proton fluxes along the GPS ns41 orbit, whose data files are delivered along with this report, are depicted to illustrate the trapped proton environment in the Medium-Earth Orbit. Uncertainties on those daily proton fluxes from two sources are evaluated: One is from the new proton-belt model that has error factors < ~3; the other is from the in-situ measurements and the error factors could be ~ 5.

  10. An Earth-mass planet orbiting α Centauri B.

    Science.gov (United States)

    Dumusque, Xavier; Pepe, Francesco; Lovis, Christophe; Ségransan, Damien; Sahlmann, Johannes; Benz, Willy; Bouchy, François; Mayor, Michel; Queloz, Didier; Santos, Nuno; Udry, Stéphane

    2012-11-08

    Exoplanets down to the size of Earth have been found, but not in the habitable zone--that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water-carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star α Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth-Sun distance).

  11. Two New Long-period Hot Subdwarf Binaries with Dwarf Companions

    Science.gov (United States)

    Barlow, Brad N.; Liss, Sandra E.; Wade, Richard A.; Green, Elizabeth M.

    2013-07-01

    Hot subdwarf stars with F-K main sequence binary companions have been known for decades, but the first orbital periods for such systems were published just recently. Current observations suggest that most have long periods, on the order of years, and that some are or once were hierarchical triple systems. As part of a survey with the Hobby-Eberly Telescope, we have been monitoring the radial velocities of several composite-spectra binaries since 2005 in order to determine their periods, velocities, and eccentricities. Here we present observations and orbital solutions for two of these systems, PG 1449+653 and PG 1701+359. Similar to the other sdB+F/G/K binaries with solved orbits, their periods are long, 909 and 734 days, respectively, and pose a challenge to current binary population synthesis models of hot subdwarf stars. Intrigued by their relatively large systemic velocities, we also present a kinematical analysis of both targets and find that neither is likely a member of the Galactic thin disk. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  12. Sticky orbits of a kicked harmonic oscillator

    International Nuclear Information System (INIS)

    Lowenstein, J H

    2005-01-01

    We study a Hamiltonian dynamical system consisting of a one-dimensional harmonic oscillator kicked impulsively in 4:1 resonance with its natural frequency, with the amplitude of the kick proportional to a sawtooth function of position. For special values of the coupling parameter, the dynamical map W relating the phase-space coordinates just prior to each kick acts locally as a piecewise affine map K on a square with rational rotation number p/q. For λ = 2cos2πp/q a quadratic irrational, a recursive return-map structure allows us to completely characterize the orbits of the map K. The aperiodic orbits of this system are sticky in the sense that they spend all of their time wandering pseudo-chaotically (with strictly zero Lyapunov exponent) in the vicinity of self-similar archipelagos of periodic islands. The same recursive structure used locally for K gives us the asymptotic scaling features of long orbits of W on the infinite plane. For some coupling parameters the orbits remain bounded, but for others the distance from the origin increases as a logarithm or power of the time. In the latter case, we find examples of sub-diffusive, diffusive, super-diffusive, and ballistic power-law behavior

  13. Local orbitals by minimizing powers of the orbital variance

    DEFF Research Database (Denmark)

    Jansik, Branislav; Høst, Stinne; Kristensen, Kasper

    2011-01-01

    's correlation consistent basis sets, it is seen that for larger penalties, the virtual orbitals become more local than the occupied ones. We also show that the local virtual HF orbitals are significantly more local than the redundant projected atomic orbitals, which often have been used to span the virtual...

  14. THE FIRST SPECTROSCOPICALLY RESOLVED SUB-PARSEC ORBIT OF A SUPERMASSIVE BINARY BLACK HOLE

    Energy Technology Data Exchange (ETDEWEB)

    Bon, E.; Jovanovic, P.; Bon, N.; Popovic, L. C. [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia); Marziani, P. [INAF, Osservatorio Astronomico di Padova, Padova (Italy); Shapovalova, A. I. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Borka Jovanovic, V.; Borka, D. [Isaac Newton Institute of Chile, Yugoslavia Branch, Belgrade (Serbia); Sulentic, J. [Instituto de Astrofisica de Andalucia, CSIC, Apdo. 3004, E-18080 Granada (Spain)

    2012-11-10

    One of the most intriguing scenarios proposed to explain how active galactic nuclei are triggered involves the existence of a supermassive binary black hole (BH) system in their cores. Here, we present an observational evidence for the first spectroscopically resolved sub-parsec orbit of a such system in the core of Seyfert galaxy NGC 4151. Using a method similar to those typically used for spectroscopic binary stars, we obtained radial velocity curves of the supermassive binary system, from which we calculated orbital elements and made estimates about the masses of the components. Our analysis shows that periodic variations in the light and radial velocity curves can be accounted for by an eccentric, sub-parsec Keplerian orbit with a 15.9 year period. The flux maximum in the light curve corresponds to the approaching phase of the secondary component toward the observer. According to the obtained results, we speculate that the periodic variations in the observed H{alpha} line shape and flux are due to shock waves generated by the supersonic motion of the components through the surrounding medium. Given the large observational effort needed to reveal this spectroscopically resolved binary orbital motion, we suggest that many such systems may exist in similar objects even if they are hard to find. Detecting more of them will provide us with insight into the BH mass growth process.

  15. THE FIRST SPECTROSCOPICALLY RESOLVED SUB-PARSEC ORBIT OF A SUPERMASSIVE BINARY BLACK HOLE

    International Nuclear Information System (INIS)

    Bon, E.; Jovanović, P.; Bon, N.; Popović, L. Č.; Marziani, P.; Shapovalova, A. I.; Borka Jovanović, V.; Borka, D.; Sulentic, J.

    2012-01-01

    One of the most intriguing scenarios proposed to explain how active galactic nuclei are triggered involves the existence of a supermassive binary black hole (BH) system in their cores. Here, we present an observational evidence for the first spectroscopically resolved sub-parsec orbit of a such system in the core of Seyfert galaxy NGC 4151. Using a method similar to those typically used for spectroscopic binary stars, we obtained radial velocity curves of the supermassive binary system, from which we calculated orbital elements and made estimates about the masses of the components. Our analysis shows that periodic variations in the light and radial velocity curves can be accounted for by an eccentric, sub-parsec Keplerian orbit with a 15.9 year period. The flux maximum in the light curve corresponds to the approaching phase of the secondary component toward the observer. According to the obtained results, we speculate that the periodic variations in the observed Hα line shape and flux are due to shock waves generated by the supersonic motion of the components through the surrounding medium. Given the large observational effort needed to reveal this spectroscopically resolved binary orbital motion, we suggest that many such systems may exist in similar objects even if they are hard to find. Detecting more of them will provide us with insight into the BH mass growth process.

  16. Nuclear Pedigree Criteria of Suspected HNPCC

    Directory of Open Access Journals (Sweden)

    Kładny Józef

    2003-01-01

    Full Text Available Abstract The criteria for the diagnosis of HNPCC established by the ICG-HNPCC are very restrictive as they do not allow for the diagnosis of a large number of "suspected HNPCC" cases - these are families which do no fulfill the strict diagnostic "Amsterdam criteria", but do present with several pedigree and clinical features characteristic for HNPCC. Several series of families suspected of harboring germline mutations in DNA mismatch repair genes have been studied for germline changes in DNA mismatch repair genes and a mutation rate of somewhere between 8-60% was found. Therefore a subgroup of members of the ICG-HNPCC has been working on pedigree/clinical diagnostic criteria for suspected HNPCC. Materials and methods Part I The study was based on two series of colorectal cancer (CRC cases: 1 HNPCC - this group comprised 190 patients affected by CRC from randomly selected families which fulfilled the Amsterdam II criteria registered in Düsseldorf, Germany (102 cases of CRC, Denmark (18 CRCs, Leiden, Holland (23 CRCs and Szczecin, Poland (47 CRCs. 2 Consecutive CRCs - this group comprised 629 (78.0% of 806 individuals with CRC diagnosed in 1991-1997 in the city of Szczecin (ca. 400,000 of inhabitants, Poland. Nuclear pedigrees in both groups were compared for frequency of occurrence of clinical features, that have been shown to be associated with HNPCC. Part II 52 consecutive CRC cases from Szczecin, matching the criteria recognized in part I as appropriate for diagnosis of cases "suspected of HNPCC" were studied for the occurrence of germline hMSH2/hMLH1 constitutional mutations using "exon by exon" sequencing. Results The combination of features - i.e. the occurrence of an HNPCC associated cancer (CRC or cancer of the endometrium, small bowel or urinary tract in a 1st degree relative of a CRC patient; at least one of the patients being diagnosed under age of 50 - appeared to be strongly associated to HNPCC with an OR - 161. Constitutional

  17. Successful endoscopic management with Mitomycin C application for sinusitis with orbital cellulitis

    Directory of Open Access Journals (Sweden)

    Anil S Harugop

    2013-01-01

    Full Text Available Background: Sinusitis with orbital complication is a potentially fatal disease that has been known since the days of Hippocrates. Primary sinus infection is the most common cause of orbital cellulitis. It is an emergency that threatens not only vision but also life from complications such as meningitis, cavernous sinus thrombosis, and brain abscess. Surgical intervention is mandatory whenever antibiotic treatment fails. There are two surgical options for the drainage, an external approach via a Lynch incision and an intranasal endoscopic procedure. Materials and Methods: Five patients with orbital cellulitis secondary to acute on chronic rhinosinusitis were included in the study from the period of 2010 - 2011. All five patients did not respond to medical management and hence underwent endoscopic sinus surgery with treatment of orbital pathology. At the end of the surgical procedure Mitomycin C in a concentration of 0.4mg/ml was applied with a cottonoid for a period of 4 minutes to prevent chance of adhesion formation. Results: In this series 3 females and 2 male patient with orbital cellulitis secondary to acute on chronic rhinosinusitis underwent endoscopic sinus surgery with treatment of orbital pathology. All 5 patients showed subjective and objective improvement within one week of endoscopic management. Conclusion: Though antibiotics have altered the course of sinusitis, its grave complications still persist in our environment. The excellent results and the absence of any major complications of endoscopic sinus surgery and drainage of abscess with application of Mitomycin C can be recommended as the preferred surgical technique.

  18. Outcomes in Diabetic Patients Undergoing Orbital Atherectomy System.

    Science.gov (United States)

    Lee, Michael S; Shlofmitz, Evan; Nguyen, Heajung; Shlofmitz, Richard A

    2016-10-01

    We evaluated the angiographic and clinical outcomes of orbital atherectomy to treat severely calcified coronary lesions in diabetic and non-diabetic patients. Diabetics have increased risk for death, myocardial infarction, and target vessel revascularization after percutaneous coronary intervention. Severely calcified coronary lesions are associated with increased cardiac events. Orbital atherectomy facilitates stent delivery and optimizes stent expansion by modifying severely calcified plaque. Outcomes in diabetic patients who undergo orbital atherectomy have not been reported. Our retrospective multicenter registry included 458 consecutive real-world patients with severely calcified coronary arteries who underwent orbital atherectomy. The primary safety endpoint was the rate of major adverse cardiac and cerebrovascular events at 30 days. Diabetics represented 42.1% (193/458) of the entire cohort. The primary endpoint was similar in diabetics and non-diabetics (1.0% vs. 3.0%%, P = 0.20), as were 30-day rates of death (0.5% vs. 1.9%, P = 0.41), myocardial infarction (0.5% vs. 1.5%, P = 0.40), target vessel revascularization (0% vs. 0%, P = 1), and stroke (0% vs. 0.4%, P > 0.9). Angiographic complications and stent thrombosis rate were low and did not differ between the 2 groups. Diabetics represented a sizeable portion of patients who underwent orbital atherectomy. Diabetics who had severely calcified coronary arteries and underwent orbital atherectomy had low event rates that were similar to non-diabetics. Orbital atherectomy appears to be a viable treatment strategy for diabetic patients. Randomized trials with longer-term follow-up are needed to determine the ideal treatment strategy for diabetics. © 2016, Wiley Periodicals, Inc.

  19. Hyperkalaemic periodic paralysis: a rare presentation of Addison's disease.

    Science.gov (United States)

    Sowden, J. M.; Borsey, D. Q.

    1989-01-01

    A 44 year old man with longstanding diabetes mellitus gave a 6-month history of periodic attacks of flaccid quadriplegia. Following one of these episodes he was admitted for assessment. In view of persistent hyperkalaemia, hypoadrenalism was suspected and Addison's disease was confirmed biochemically. Adrenal replacement therapy restored the potassium levels to normal and resulted in no further attacks of paralysis. PMID:2594601

  20. Orbit-related sea level errors for TOPEX altimetry at seasonal to decadal timescales

    Science.gov (United States)

    Esselborn, Saskia; Rudenko, Sergei; Schöne, Tilo

    2018-03-01

    Interannual to decadal sea level trends are indicators of climate variability and change. A major source of global and regional sea level data is satellite radar altimetry, which relies on precise knowledge of the satellite's orbit. Here, we assess the error budget of the radial orbit component for the TOPEX/Poseidon mission for the period 1993 to 2004 from a set of different orbit solutions. The errors for seasonal, interannual (5-year), and decadal periods are estimated on global and regional scales based on radial orbit differences from three state-of-the-art orbit solutions provided by different research teams: the German Research Centre for Geosciences (GFZ), the Groupe de Recherche de Géodésie Spatiale (GRGS), and the Goddard Space Flight Center (GSFC). The global mean sea level error related to orbit uncertainties is of the order of 1 mm (8 % of the global mean sea level variability) with negligible contributions on the annual and decadal timescales. In contrast, the orbit-related error of the interannual trend is 0.1 mm yr-1 (27 % of the corresponding sea level variability) and might hamper the estimation of an acceleration of the global mean sea level rise. For regional scales, the gridded orbit-related error is up to 11 mm, and for about half the ocean the orbit error accounts for at least 10 % of the observed sea level variability. The seasonal orbit error amounts to 10 % of the observed seasonal sea level signal in the Southern Ocean. At interannual and decadal timescales, the orbit-related trend uncertainties reach regionally more than 1 mm yr-1. The interannual trend errors account for 10 % of the observed sea level signal in the tropical Atlantic and the south-eastern Pacific. For decadal scales, the orbit-related trend errors are prominent in a several regions including the South Atlantic, western North Atlantic, central Pacific, South Australian Basin, and the Mediterranean Sea. Based on a set of test orbits calculated at GFZ, the sources of the

  1. Orbit-related sea level errors for TOPEX altimetry at seasonal to decadal timescales

    Directory of Open Access Journals (Sweden)

    S. Esselborn

    2018-03-01

    Full Text Available Interannual to decadal sea level trends are indicators of climate variability and change. A major source of global and regional sea level data is satellite radar altimetry, which relies on precise knowledge of the satellite's orbit. Here, we assess the error budget of the radial orbit component for the TOPEX/Poseidon mission for the period 1993 to 2004 from a set of different orbit solutions. The errors for seasonal, interannual (5-year, and decadal periods are estimated on global and regional scales based on radial orbit differences from three state-of-the-art orbit solutions provided by different research teams: the German Research Centre for Geosciences (GFZ, the Groupe de Recherche de Géodésie Spatiale (GRGS, and the Goddard Space Flight Center (GSFC. The global mean sea level error related to orbit uncertainties is of the order of 1 mm (8 % of the global mean sea level variability with negligible contributions on the annual and decadal timescales. In contrast, the orbit-related error of the interannual trend is 0.1 mm yr−1 (27 % of the corresponding sea level variability and might hamper the estimation of an acceleration of the global mean sea level rise. For regional scales, the gridded orbit-related error is up to 11 mm, and for about half the ocean the orbit error accounts for at least 10 % of the observed sea level variability. The seasonal orbit error amounts to 10 % of the observed seasonal sea level signal in the Southern Ocean. At interannual and decadal timescales, the orbit-related trend uncertainties reach regionally more than 1 mm yr−1. The interannual trend errors account for 10 % of the observed sea level signal in the tropical Atlantic and the south-eastern Pacific. For decadal scales, the orbit-related trend errors are prominent in a several regions including the South Atlantic, western North Atlantic, central Pacific, South Australian Basin, and the Mediterranean Sea. Based on a set of test

  2. Orbital Dynamics of Low-Earth Orbit Laser-Propelled Space Vehicles

    International Nuclear Information System (INIS)

    Yamakawa, Hiroshi; Funaki, Ikkoh; Komurasaki, Kimiya

    2008-01-01

    Trajectories applicable to laser-propelled space vehicles with a laser station in low-Earth orbit are investigated. Laser vehicles are initially located in the vicinity of the Earth-orbiting laser station in low-earth orbit at an altitude of several hundreds kilometers, and are accelerated by laser beaming from the laser station. The laser-propelled vehicles start from low-earth orbit and finally escape from the Earth gravity well, enabling interplanetary trajectories and planetary exploration

  3. Provider-initiated HIV testing and counselling for TB patients and suspects in Nairobi, Kenya.

    Science.gov (United States)

    Odhiambo, J; Kizito, W; Njoroge, A; Wambua, N; Nganga, L; Mburu, M; Mansoer, J; Marum, L; Phillips, E; Chakaya, J; De Cock, K M

    2008-03-01

    Integrated tuberculosis (TB) and human immunodeficiency virus (HIV) services in a resource-constrained setting. Pilot provider-initiated HIV testing and counselling (PITC) for TB patients and suspects. Through partnerships, resources were mobilised to establish and support services. After community sensitisation and staff training, PITC was introduced to TB patients and then to TB suspects from December 2003 to December 2005. Of 5457 TB suspects who received PITC, 89% underwent HIV testing. Although not statistically significant, TB suspects with TB disease had an HIV prevalence of 61% compared to 63% for those without. Of the 614 suspects who declined HIV testing, 402 (65%) had TB disease. Of 2283 patients referred for cotrimoxazole prophylaxis, 1951 (86%) were enrolled, and of 1727 patients assessed for antiretroviral treatment (ART), 1618 (94%) were eligible and 1441 (83%) started treatment. PITC represents a paradigm shift and is feasible and acceptable to TB patients and TB suspects. Clear directives are nevertheless required to change practice. When offered to TB suspects, PITC identifies large numbers of persons requiring HIV care. Community sensitisation, staff training, multitasking and access to HIV care contributed to a high acceptance of HIV testing. Kenya is using this experience to inform national response and advocate wide PITC implementation in settings faced with the TB-HIV epidemic.

  4. RAPID ORBITAL DECAY IN THE 12.75-MINUTE BINARY WHITE DWARF J0651+2844

    International Nuclear Information System (INIS)

    Hermes, J. J.; Winget, D. E.; Kilic, Mukremin; Gianninas, A.; Kenyon, Scott J.; Brown, Warren R.; Allende Prieto, Carlos; Cabrera-Lavers, Antonio; Mukadam, Anjum S.

    2012-01-01

    We report the detection of orbital decay in the 12.75-minute, detached binary white dwarf (WD) SDSS J065133.338+284423.37 (hereafter J0651). Our photometric observations over a 13 month baseline constrain the orbital period to 765.206543(55) s and indicate that the orbit is decreasing at a rate of (– 9.8 ± 2.8) × 10 –12 s s –1 (or –0.31 ± 0.09 ms yr –1 ). We revise the system parameters based on our new photometric and spectroscopic observations: J0651 contains two WDs with M 1 = 0.26 ± 0.04 M ☉ and M 2 = 0.50 ± 0.04 M ☉ . General relativity predicts orbital decay due to gravitational wave radiation of (– 8.2 ± 1.7) × 10 –12 s s –1 (or –0.26 ± 0.05 ms yr –1 ). Our observed rate of orbital decay is consistent with this expectation. J0651 is currently the second-loudest gravitational wave source known in the milli-Hertz range and the loudest non-interacting binary, which makes it an excellent verification source for future missions aimed at directly detecting gravitational waves. Our work establishes the feasibility of monitoring this system's orbital period decay at optical wavelengths.

  5. Unexpected MRI findings in clinically suspected Legg-Calve-Perthes disease

    Energy Technology Data Exchange (ETDEWEB)

    Lobert, Philip F.; Dillman, Jonathan R.; Strouse, Peter J.; Hernandez, Ramiro J. [University of Michigan Health System, Department of Radiology, Section of Pediatric Radiology, C.S. Mott Children' s Hospital/F3503, Ann Arbor, MI (United States)

    2011-03-15

    In the setting of clinically suspected Legg-Calve-Perthes (LCP) disease and negative/equivocal radiographs, contrast-enhanced MRI can be performed to confirm the diagnosis. To determine the frequency of unexpected causes of hip pain as identified by MRI in children with clinically suspected LCP disease and negative/equivocal radiographs. All pediatric contrast-enhanced MRI examinations of the pelvis and hips performed between January 2000 and February 2009 to evaluate for possible LCP disease in the setting of negative/equivocal radiographs were identified. MRI examinations performed to evaluate for secondary avascular necrosis were excluded. Imaging reports were retrospectively reviewed for unexpected clinically important causes of hip pain. Thirty-six pediatric patients underwent contrast-enhanced MRI examinations for clinically suspected LCP disease in the setting of negative/equivocal radiographs. Twenty-two (61%) imaging studies were normal, while four (11%) imaging studies demonstrated findings consistent with LCP disease. Ten (28%) imaging studies revealed unexpected clinically important causes of hip pain, including nonspecific unilateral joint effusion and synovitis (n = 7, juvenile chronic arthritis was eventually diagnosed in 3 patients), sacral fracture (n = 1), apophyseal injury (n = 1), and femoral head subluxation (n = 1). MRI frequently reveals unexpected clinically important causes of hip pain in children with suspected LCP disease and negative/equivocal radiographs. (orig.)

  6. Percutaneous cholecystocentesis in cats with suspected hepatobiliary disease.

    Science.gov (United States)

    Byfield, Victoria L; Callahan Clark, Julie E; Turek, Bradley J; Bradley, Charles W; Rondeau, Mark P

    2017-12-01

    Objectives The objective was to evaluate the safety and diagnostic utility of percutaneous ultrasound-guided cholecystocentesis (PUC) in cats with suspected hepatobiliary disease. Methods Medical records of 83 cats with suspected hepatobiliary disease that underwent PUC were retrospectively reviewed. Results At the time of PUC, at least one additional procedure was performed in 79/83 cats, including hepatic aspiration and/or biopsy (n = 75) and splenic aspiration (n = 18). Complications were noted in 14/83 cases, including increased abdominal fluid (n = 11), needle-tip occlusion (n = 1), failed first attempt to penetrate the gall bladder wall (n = 1) and pneumoperitoneum (n = 1). There were no reports of gall bladder rupture, bile peritonitis or hypotension necessitating treatment with vasopressor medication. Blood products were administered to 7/83 (8%) cats. Seventy-two cats (87%) survived to discharge. Of the cats that were euthanized (9/83) or died (2/83), none were reported as a definitive consequence of PUC. Bacteria were identified cytologically in 10/71 samples (14%); all 10 had a positive aerobic bacterial culture. Bile culture was positive in 11/80 samples (14%). Of the cases with a positive bile culture, cytological description of bacteria corresponded to the organism cultured in fewer than 50% of cases. The most common cytologic diagnosis was hepatic lipidosis (49/66). The most common histopathologic diagnosis was cholangitis (10/21). Conclusions and relevance PUC was safe in this group of cats with suspected hepatobiliary disease. Complications were likely associated with ancillary procedures performed at the time of PUC. Bile analysis yielded an abnormal result in nearly one-third of cats with suspected hepatobiliary disease. Complete agreement between bile cytology and culture was lacking. Further evaluation of the correlation between bile cytology and bile culture is warranted.

  7. Photometry of the long period dwarf nova GY Hya

    Science.gov (United States)

    Bruch, Albert; Monard, Berto

    2017-08-01

    Although comparatively bright, the cataclysmic variable GY Hya has not attracted much attention in the past. As part of a project to better characterize such systems photometrically, we observed light curves in white light, each spanning several hours, at Bronberg Observatory, South Africa, in 2004 and 2005, and at the Observatório do Pico dos Dias, Brazil, in 2014 and 2016. These data permit to study orbital modulations and their variations from season to season. The orbital period, already known from spectroscopic observations of Peters and Thorstensen (2005), is confirmed through strong ellipsoidal variations of the mass donor star in the system and the presence of eclipses of both components. A refined period of 0.34723972 (6) days and revised ephemeries are derived. Seasonal changes in the average orbital light curve can qualitatively be explained by variations of the contribution of a hot spot to the system light together with changes of the disk radius. The amplitude of the ellipsoidal variations and the eclipse contact phases permit to put some constraints on the mass ratio, orbital inclination and the relative brightness of the primary and secondary components. There are some indications that the disk radius during quiescence, expressed in units of the component separation, is smaller than in other dwarf novae.

  8. ORBIT FEEDBACK CONTROL FOR THE LHC Prototyping at the SPS

    CERN Document Server

    Steinhagen, Ralph J

    2004-01-01

    The Large Hadron Collider (LHC) is the next generation proton collider that is presently built at CERN. The LHC will be installed in the former LEP (Large Electron Positron Collider) tunnel. The presence of a high intensity beam in an environment of cryogenic magnets requires an excellent control of particle losses from the beam. Eventually the performance of the LHC may be limited by the ability to control the beam losses. The performance of the LHC cleaning system depends critically on the beam position stability. Ground motion, field and alignment imperfections and beam manipulations may cause orbit movements. The role of the future LHC Orbit Feedback System is the minimisation of closed orbit perturbations by periodically measuring and steering the transverse beam position back to its reference position. This diploma thesis focuses on the design and prototyping of an orbit feedback system at the SPS. The design is based on a separation of the steering problem into space and time. While the correction in s...

  9. CONGENITAL ORBITAL TERATOMA

    African Journals Online (AJOL)

    was done without contrast and 3mm/5mm/10mm slices were obtained to cover the orbit, skull base and brain. The findings included a soft tissue mass arising from the orbit. The left eye ball was extra orbital. There was no defect .... love's Short Practice of Surgery. 7 Edition,. Levis London, 1997; 45-64. 2. Orbital tumor Part 1, ...

  10. Confirmation of Earth-Mass Planets Orbiting the Millisecond Pulsar PSR B1257 + 12.

    Science.gov (United States)

    Wolszczan, A

    1994-04-22

    The discovery of two Earth-mass planets orbiting an old ( approximately 10(9) years), rapidly spinning neutron star, the 6.2-millisecond radio pulsar PSR B1257+12, was announced in early 1992. It was soon pointed out that the approximately 3:2 ratio of the planets' orbital periods should lead to accurately predictable and possibly measurable gravitational perturbations of their orbits. The unambiguous detection of this effect, after 3 years of systematic timing observations of PSR B1257+12 with the 305-meter Arecibo radiotelescope, as well as the discovery of another, moon-mass object in orbit around the pulsar, constitutes irrefutable evidence that the first planetary system around a star other than the sun has been identified.

  11. EVIDENCE FOR PERIODICITY IN 43 YEAR-LONG MONITORING OF NGC 5548

    Energy Technology Data Exchange (ETDEWEB)

    Bon, E.; Bon, N.; Jovanović, P.; Popović, L. Č.; Stalevski, M. [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia); Zucker, S. [Department of Geosciences, Tel-Aviv University, Tel-Aviv 6997801 (Israel); Netzer, H. [School of Physics and Astronomy and the Wise Observatory, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 6997801 (Israel); Marziani, P. [INAF, Osservatorio Astronomico di Padova, Padova (Italy); Shapovalova, A. I.; Burenkov, A. N. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Komossa, S.; Britzen, S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn (Germany); Gaskell, C. M. [Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Chavushyan, V. H.; Valdés, J. R. [Instituto Nacional de Astrofsica, Óptica y Electrónica, Apartado Postal 51, CP 72000, Puebla, Pue, Mexico (Mexico); Sergeev, S. [Crimean Astrophysical Observatory, P/O Nauchny, Republic of Crimea 298409 (Russian Federation); Mura, G. La [Dipartimento di Fisica e Astronomia “G. Galilei,” Università degli Studi di Padova, Vicolo dell’Osservatorio 3, I-35122—Padova (Italy)

    2016-08-01

    We present an analysis of 43 years (1972 to 2015) of spectroscopic observations of the Seyfert 1 galaxy NGC 5548. This includes 12 years of new unpublished observations (2003 to 2015). We compiled about 1600 H β spectra and analyzed the long-term spectral variations of the 5100 Å continuum and the H β line. Our analysis is based on standard procedures, including the Lomb–Scargle method, which is known to be rather limited to such heterogeneous data sets, and a new method developed specifically for this project that is more robust and reveals a ∼5700 day periodicity in the continuum light curve, the H β light curve, and the radial velocity curve of the red wing of the H β line. The data are consistent with orbital motion inside the broad emission line region of the source. We discuss several possible mechanisms that can explain this periodicity, including orbiting dusty and dust-free clouds, a binary black hole system, tidal disruption events, and the effect of an orbiting star periodically passing through an accretion disk.

  12. Handbook for Response to Suspect Radioactive Materials

    International Nuclear Information System (INIS)

    Cliff, William C.; Pappas, Richard A.; Arthur, Richard J.

    2005-01-01

    This document provides response actions to be performed following the initial port, airport, or border crossing discovery of material that is suspected of being radioactive. The purpose of this guide is to provide actions appropriate for handling radioactive material

  13. On an efficient and accurate method to integrate restricted three-body orbits

    Science.gov (United States)

    Murison, Marc A.

    1989-01-01

    This work is a quantitative analysis of the advantages of the Bulirsch-Stoer (1966) method, demonstrating that this method is certainly worth considering when working with small N dynamical systems. The results, qualitatively suspected by many users, are quantitatively confirmed as follows: (1) the Bulirsch-Stoer extrapolation method is very fast and moderately accurate; (2) regularization of the equations of motion stabilizes the error behavior of the method and is, of course, essential during close approaches; and (3) when applicable, a manifold-correction algorithm reduces numerical errors to the limits of machine accuracy. In addition, for the specific case of the restricted three-body problem, even a small eccentricity for the orbit of the primaries drastically affects the accuracy of integrations, whether regularized or not; the circular restricted problem integrates much more accurately.

  14. A simple MRI protocol in patients with clinically suspected appendicitis: results in 138 patients and effect on outcome of appendectomy

    International Nuclear Information System (INIS)

    Cobben, Lodewijk; Groot, Ingrid; Kingma, Lucas; Coerkamp, Emile; Puylaert, Julien; Blickman, Johan

    2009-01-01

    To establish the value of breathhold magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis. Over a 14-month period, 138 patients clinically suspected of having appendicitis were evaluated prospectively with MRI and comprised the study group. Fast turbo spin-echo breathhold T1, T2 and T2 fat suppression sequences were used in coronal and axial planes. The imaging results were recorded separately and subsequently correlated with clinical, radiological and histopathological follow-up. The effect of imaging strategies in patients suspected of appendicitis on hospital resources was calculated. Sixty-two of the 138 patients had a histopathologically proven appendicitis. MRI determined appendicitis in 63 patients, with one examination being false positive. The resulting sensitivity and specificity were 100% and 99%, respectively. MRI showed an alternative diagnosis in 41 of the 75 remaining patients. In 22 of the remaining 34 patients, a normal appendix was depicted with MRI. In two patients, where MRI showed no appendicitis, an alternative diagnosis or normal appendix, an unnecessary appendectomy was performed. The overall effect of using MRI in patients suspected of appendicitis on the use of hospital resources could have been a net saving between EUR 55,746 and EUR 72,534. MRI has a high accuracy in detecting and excluding appendicitis, an alternative diagnosis or showing the normal appendix, and can be a valuable and cost-effective tool in the workup of patients clinically suspected of having appendicitis. (orig.)

  15. A simple MRI protocol in patients with clinically suspected appendicitis: results in 138 patients and effect on outcome of appendectomy

    Energy Technology Data Exchange (ETDEWEB)

    Cobben, Lodewijk [Medisch Centrum Haaglanden, Department of Radiology, Leidschendam (Netherlands); Groot, Ingrid [Medisch Centrum Haaglanden, Department of Surgery, Leidschendam (Netherlands); Kingma, Lucas; Coerkamp, Emile; Puylaert, Julien [Medisch Centrum Haaglanden, Department of Radiology, Den Haag (Netherlands); Blickman, Johan [Universitair Medisch Centrum St Radboud, Department of Radiology, Geert Grooteplein 10, GA, Nijmegen (Netherlands)

    2009-05-15

    To establish the value of breathhold magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis. Over a 14-month period, 138 patients clinically suspected of having appendicitis were evaluated prospectively with MRI and comprised the study group. Fast turbo spin-echo breathhold T1, T2 and T2 fat suppression sequences were used in coronal and axial planes. The imaging results were recorded separately and subsequently correlated with clinical, radiological and histopathological follow-up. The effect of imaging strategies in patients suspected of appendicitis on hospital resources was calculated. Sixty-two of the 138 patients had a histopathologically proven appendicitis. MRI determined appendicitis in 63 patients, with one examination being false positive. The resulting sensitivity and specificity were 100% and 99%, respectively. MRI showed an alternative diagnosis in 41 of the 75 remaining patients. In 22 of the remaining 34 patients, a normal appendix was depicted with MRI. In two patients, where MRI showed no appendicitis, an alternative diagnosis or normal appendix, an unnecessary appendectomy was performed. The overall effect of using MRI in patients suspected of appendicitis on the use of hospital resources could have been a net saving between EUR 55,746 and EUR 72,534. MRI has a high accuracy in detecting and excluding appendicitis, an alternative diagnosis or showing the normal appendix, and can be a valuable and cost-effective tool in the workup of patients clinically suspected of having appendicitis. (orig.)

  16. K2-137 b: an Earth-sized planet in a 4.3-h orbit around an M-dwarf

    Science.gov (United States)

    Smith, A. M. S.; Cabrera, J.; Csizmadia, Sz; Dai, F.; Gandolfi, D.; Hirano, T.; Winn, J. N.; Albrecht, S.; Alonso, R.; Antoniciello, G.; Barragán, O.; Deeg, H.; Eigmüller, Ph; Endl, M.; Erikson, A.; Fridlund, M.; Fukui, A.; Grziwa, S.; Guenther, E. W.; Hatzes, A. P.; Hidalgo, D.; Howard, A. W.; Isaacson, H.; Korth, J.; Kuzuhara, M.; Livingston, J.; Narita, N.; Nespral, D.; Nowak, G.; Palle, E.; Pätzold, M.; Persson, C. M.; Petigura, E.; Prieto-Arranz, J.; Rauer, H.; Ribas, I.; Van Eylen, V.

    2018-03-01

    We report the discovery in K2's Campaign 10 of a transiting terrestrial planet in an ultra-short-period orbit around an M3-dwarf. K2-137 b completes an orbit in only 4.3 h, the second shortest orbital period of any known planet, just 4 min longer than that of KOI 1843.03, which also orbits an M-dwarf. Using a combination of archival images, adaptive optics imaging, radial velocity measurements, and light-curve modelling, we show that no plausible eclipsing binary scenario can explain the K2 light curve, and thus confirm the planetary nature of the system. The planet, whose radius we determine to be 0.89 ± 0.09 R⊕, and which must have an iron mass fraction greater than 0.45, orbits a star of mass 0.463 ± 0.052 M⊙ and radius 0.442 ± 0.044 R⊙.

  17. Clinical and microbiological features of dientamoebiasis in patients suspected of suffering from a parasitic gastrointestinal illness: a comparison of Dientamoeba fragilis and Giardia lamblia infections

    NARCIS (Netherlands)

    Vandenberg, Olivier; Peek, Ron; Souayah, Hichem; Dediste, Anne; Buset, Michel; Scheen, Robert; Retore, Patricia; Zissis, Georges; van Gool, Tom

    2006-01-01

    To describe the clinical and microbiological features of Dientamoeba fragilis and Giardia lamblia infected patients, and to analyze the genetic variation of D. fragilis strains. For a period of two years, all stool samples collected from patients suspected of having a parasitic gastrointestinal

  18. [Suspected Alzheimer's disease. Selection of outpatients for neuropsychological assessment].

    Science.gov (United States)

    Wolf, S A; Henry, M; Deike, R; Ebert, A D; Wallesch, C-W

    2008-04-01

    Incipient Alzheimer's disease (AD) is frequently suspected by neurologists and psychiatrists, but diagnosis is difficult to establish. The aim of this report was to analyse to what extent suspicion is confirmed by a comprehensive neuropsychological examination intended to distinguish different types of dementia. Descriptive data analysis was used for investigating the differential diagnoses of 47 outpatients with suspected AD referred to a department of neuropsychology by physicians in private practice. Data analysis was based upon the NINCDS-ADRDA diagnostic criteria of AD. Only 38% of the outpatients examined with suspected AD met the NINCDS-ADRDA diagnostic criteria for AD or mixed dementia from a neuropsychological point of view, whereas 22% met criteria for other types of dementia. The remaining patients met criteria for distinct differential diagnoses (23%) or lacked pathological findings in neuropsychological functions (17%). Neuropsychology is an essential part in the differential diagnosis of mild to moderate dementias. It can aid in differential therapeutic considerations concerning the treatment of dementia, for example in selecting appropriate treatments or avoiding expensive but inappropriate ones.

  19. Police officers' perceptions and experiences with mentally disordered suspects.

    Science.gov (United States)

    Oxburgh, Laura; Gabbert, Fiona; Milne, Rebecca; Cherryman, Julie

    Despite mentally disordered suspects being over-represented within the criminal justice system, there is a dearth of published literature that examines police officers' perceptions when interviewing this vulnerable group. This is concerning given that police officers are increasingly the first point of contact with these individuals. Using a Grounded Theory approach, this study examined 35 police officers' perceptions and experiences when interviewing mentally disordered suspects. Current safeguards, such as Appropriate Adults, and their experiences of any training they received were also explored. A specially designed questionnaire was developed and distributed across six police forces in England and Wales. Nine conceptual categories emerged from the data that highlighted how police officers' level of experience impacted upon their perceptions when dealing with this cohort. As a consequence, a new model grounded within Schema Theory has emerged termed Police Experience Transitional Model. Implications include the treatment and outcome of mentally disordered suspects being heavily dependent on whom they encounter within the criminal justice system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Radiovolumetry of the orbit

    International Nuclear Information System (INIS)

    Abujamra, S.

    1983-01-01

    The authors present a method called ''Radiovolumetry of the orbit'' that permits the evaluation of the orbital volume from anteroposterior skull X-Rays (CALDWELL 30 0 position). The research was based in the determination of the orbital volume with lead spheres, in 1010 orbits of 505 dry skulls of Anatomy Museums. After the dry skulls was X-rayed six frontal orbital diameters were made, with care to correct the radiographic amplification. PEARSON correlation coeficient test was applied between the mean orbital diameter and the orbital volume. The result was r = 0,8 with P [pt

  1. Solar Effects of Low-Earth Orbit objects in ORDEM 3.0

    Science.gov (United States)

    Vavrin, A. B.; Anz-Meador, P.; Kelley, R. L.

    2014-01-01

    Variances in atmospheric density are directly related to the variances in solar flux intensity between 11- year solar cycles. The Orbital Debris Engineering Model (ORDEM 3.0) uses a solar flux table as input for calculating orbital lifetime of intact and debris objects in Low-Earth Orbit. Long term projections in solar flux activity developed by the NASA Orbital Debris Program Office (ODPO) extend the National Oceanic and Atmospheric Administration Space Environment Center (NOAA/SEC) daily historical flux values with a 5-year projection. For purposes of programmatic scheduling, the Q2 2009 solar flux table was chosen for ORDEM 3.0. Current solar flux activity shows that the current solar cycle has entered a period of lower solar flux intensity than previously forecasted in 2009. This results in a deviation of the true orbital debris environment propagation in ORDEM 3.0. In this paper, we present updated orbital debris populations in LEO using the latest solar flux values. We discuss the effects on recent breakup events such as the FY-1C anti-satellite test and the Iridium 33 / Cosmos 2251 accidental collision. Justifications for chosen solar flux tables are discussed.

  2. IGR J14257-6117, a magnetic accreting white dwarf with a very strong strong X-ray orbital modulation

    Science.gov (United States)

    Bernardini, F.; de Martino, D.; Mukai, K.; Falanga, M.

    2018-04-01

    IGR J14257-6117 is an unclassified source in the hard X-ray catalogues. Optical follow-ups suggest it could be a Cataclysmic Variable of the magnetic type. We present the first high S/N X-ray observation performed by XMM-Newton at 0.3-10 keV, complemented with 10-80 keV coverage by Swift/BAT, aimed at revealing the source nature. We detected for the first time a fast periodic variability at 509.5 s and a longer periodic variability at 4.05 h, ascribed to the white dwarf (WD) spin and binary orbital periods, respectively. These unambiguously identify IGR J14257-6117 as a magnetic CV of the Intermediate Polar (IP) type. The energy resolved light curves at both periods reveal amplitudes decreasing with increasing energy, with the orbital modulation reaching ˜100% in the softest band. The energy spectrum shows optically thin thermal emission with an excess at the iron complex, absorbed by two dense media (NH ˜ 1022 - 23 cm-2), partially covering the X-ray source. These are likely localised in the magnetically confined accretion flow above the WD surface and at the disc rim, producing the energy dependent spin and orbital variabilities, respectively. IGR J14257-6117, joins the group of strongest orbitally modulated IPs now counting four systems. Drawing similarities with low-mass X-ray binaries displaying orbital dips, these IPs should be seen at large orbital inclinations allowing azimuthally extended absorbing material fixed in the binary frame to intercept the line of sight. For IGR J14257-6117, we estimate (50o ≲ i ≲ 70o). Whether also the mass accretion rate plays a role in the large orbital modulations in IPs cannot be established with the present data.

  3. Prevalence and Correlates of Suspected Nonalcoholic Fatty Liver Disease in Chinese Children

    Directory of Open Access Journals (Sweden)

    Peige Song

    2017-04-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD has become a serious public health problem worldwide; however, the availability of information on the prevalence of NAFLD in the general pediatric population is still limited. The primary aim of this study was to reveal the prevalence and correlates of suspected NAFLD in Chinese children at the national level. Data from the China Health and Nutrition Surveys (CHNS was used. Weight, height, waist circumference (WC, blood pressure (BP were measured for children aged 7–18 years. Blood samples were collected and analyzed. Children were classified as having suspected NAFLD if common causes of liver disease were excluded, and serum alanine aminotransferase (ALT values were above the established thresholds (>22.1 IU/L for girls and >25.8 IU/L for boys. A percentage of 9.03% (75 out of 831 of Chinese children was found to have suspected NAFLD. Overweight and obesity according to BMI percentiles, abdominal obesity, hyperuricemia (uric acid (UA > 327 μmol/L, and elevated total cholesterol (TC were all detected as the correlates of childhood suspected NAFLD when adjusting for other factors. Our study revealed the prevalence of suspected NAFLD in general Chinese children at the national level for the first time. Our findings indicate that suspected NAFLD in children is associated with increasing childhood morbidities, further studies are needed to better understand the prevalence of childhood NAFLD and its correlates, and large-scale programs should be launched to screen NAFLD in the pediatric population in China.

  4. [Exenteration of the Orbit for Basal Cell Carcinoma].

    Science.gov (United States)

    Furdová, A; Horkovičová, K; Krčová, I; Krásnik, V

    2015-08-01

    Primary treatment of basal cell carcinoma of the lower eyelid and the inner corner is essentially surgical, but advanced lesions require extensive surgical interventions. In some cases it is necessary to continue with the mutilating surgery--exenteration of the orbit. In this work we evaluate the indications of radical solutions in patients with basal cell carcinoma invading the orbit and the subsequent possibility for individually made prosthesis to cover the defect of the cavity. Indications to exenteration of the orbit in patients with basal cell carcinoma findings in 2008-2013. Case report of 2 patients. In period 2008-20013 at the Dept. of Ophthalmology, Comenius University in Bratislava totally 221 patients with histologically confirmed basal cell carcinoma of the eyelids and the inner corner were treated. In 5 cases (2.7 %) with infiltration of the orbit the radical surgical procedure, exenteration was necessary. In 3 patients exenteration was indicated as the first surgical procedure in the treatment of basal cell carcinoma, since they had never visited ophthalmologist before only at in the stage of infiltration of the orbit (stage T4). In one case was indicated exenteration after previous surgical interventions and relapses. After healing the cavity patients got individually prepared epithesis. Surgical treatment of basal cell carcinoma involves the radical removal of the neoplasm entire eyelid and stage T1 or T2 can effectively cure virtually all tumors with satisfactory cosmetic and functional results. In advanced stages (T4 stage) by infiltrating the orbit by basal cell carcinoma exenteration of the orbit is necessary. This surgery is a serious situation for the patient and also for his relatives. Individually made prosthesis helps the patient to be enrolled to the social environment.

  5. Suspected Child Maltreatment: Recognize and Respond

    Science.gov (United States)

    Kemple, Kristen Mary; Kim, Hae Kyoung

    2011-01-01

    Early childhood educators spend extensive amounts of time with young children, so they are often the first adults to notice signs that a child may be abused or neglected. All educators are required by law to report suspected maltreatment, and can play an important role in preventing and responding to abuse and neglect of young children. What is…

  6. CryoSat/SIRAL Cal1 Calibration Orbits

    Science.gov (United States)

    Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso

    2017-04-01

    The main payload of CryoSat is a Ku band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for SAR processing. This allows to reach an along track resolution that is significantly improved with respect to traditional pulse-width limited altimeters. Due to the fact that SIRAL is a phase coherent pulse-width limited radar altimeter, a proper calibration approach has been developed. In fact, not only corrections for transfer function, gain and instrument path delay have to be computed (as in previous altimeters), but also corrections for phase (SAR/SARIn) and phase difference between the two receiving chains (SARIN only). Recalling that the CryoSat's orbit has a high inclination of 92° and it is non-sun-synchronous, the temperature of the SIRAL changes continuously along the orbit with a period of about 480 days and it is also function of the ascending/descending passes. By analysis of the CAL1 calibration corrections, it has been verified that the internal path delay and the instrument gain variation measured on the SIRAL are affected by the thermal status of the instrument and as a consequence they are expected to vary along the orbit. In order to gain knowledge on the calibration corrections (i.e. the instrument behavior) as function of latitude and temperature, it has been planned to command a few number of orbits where only CAL1 calibration acquisitions are continuously performed. The analysis of the CAL1 calibration corrections produced along the Calibration orbits can be also useful to verify whether the current calibration plan is able to provide sufficiently accurate corrections for the instrument acquisitions at any latitude. In 2016, the CryoSat/SIRAL Cal1 Calibration Orbits have been commanded two times, a first time the 20th of July 2016 and a second time the 24th of November 2016, and they

  7. Orbital Battleship: A Guessing Game to Reinforce Atomic Structure

    Science.gov (United States)

    Kurushkin, Mikhail; Mikhaylenko, Maria

    2016-01-01

    A competitive educational guessing game "Orbital Battleship" which reinforces Madelung's and Hund's rules, values of quantum numbers, and understanding of periodicity was designed. The game develops strategic thinking, is not time-consuming, requires minimal preparation and supervision, and is an efficient and fun alternative to more…

  8. Exterior Companions to Hot Jupiters Orbiting Cool Stars Are Coplanar

    Science.gov (United States)

    Becker, Juliette C.; Vanderburg, Andrew; Adams, Fred C.; Khain, Tali; Bryan, Marta

    2017-12-01

    The existence of hot Jupiters has challenged theories of planetary formation since the first extrasolar planets were detected. Giant planets are generally believed to form far from their host stars, where volatile materials like water exist in their solid phase, making it easier for giant planet cores to accumulate. Several mechanisms have been proposed to explain how giant planets can migrate inward from their birth sites to short-period orbits. One such mechanism, called Kozai-Lidov migration, requires the presence of distant companions in orbits inclined by more than ˜40° with respect to the plane of the hot Jupiter’s orbit. The high occurrence rate of wide companions in hot-Jupiter systems lends support to this theory for migration. However, the exact orbital inclinations of these detected planetary and stellar companions is not known, so it is not clear whether the mutual inclination of these companions is large enough for the Kozai-Lidov process to operate. This paper shows that in systems orbiting cool stars with convective outer layers, the orbits of most wide planetary companions to hot Jupiters must be well aligned with the orbits of the hot Jupiters and the spins of the host stars. For a variety of possible distributions for the inclination of the companion, the width of the distribution must be less than ˜20° to recreate the observations with good fidelity. As a result, the companion orbits are likely well aligned with those of the hot Jupiters, and the Kozai-Lidov mechanism does not enforce migration in these systems.

  9. Depressed mood, positive affect, and heart rate variability in patients with suspected coronary artery disease.

    Science.gov (United States)

    Bhattacharyya, Mimi R; Whitehead, Daisy L; Rakhit, Roby; Steptoe, Andrew

    2008-11-01

    To test associations between heart rate variability (HRV), depressed mood, and positive affect in patients with suspected coronary artery disease (CAD). Depression is associated with impaired HRV post acute cardiac events, but evidence in patients with stable coronary artery disease (CAD) is inconsistent. Seventy-six patients (52 men, 24 women; mean age = 61.1 years) being investigated for suspected CAD on the basis of symptomatology and positive noninvasive tests, completed 24-hour electrocardiograms. The Beck Depression Inventory (BDI) was administered, and positive and depressed affect was measured over the study period with the Day Reconstruction Method (DRM). A total of 46 (60.5%) patients were later found to have definite CAD. HRV was analyzed, using spectral analysis. Typical diurnal profiles of HRV were observed, with greater normalized high frequency (HF) and lower normalized low frequency (LF) power in the night compared with the day. BDI depression scores were not consistently associated with HRV. But positive affect was associated with greater normalized HF power (p = .039) and reduced normalized LF power (p = .007) independently of age, gender, medication with beta blockers, CAD status, body mass index, smoking, and habitual physical activity level. In patients with definite CAD, depressed affect assessed using the DRM was associated with reduced normalized HF power and heightened normalized LF power (p = .007) independently of covariates. Relationships between depression and HRV in patients with CAD may depend on affective experience over the monitoring period. Enhanced parasympathetic cardiac control may be a process through which positive affect protects against cardiovascular disease.

  10. Prediction Model for Relativistic Electrons at Geostationary Orbit

    Science.gov (United States)

    Khazanov, George V.; Lyatsky, Wladislaw

    2008-01-01

    We developed a new prediction model for forecasting relativistic (greater than 2MeV) electrons, which provides a VERY HIGH correlation between predicted and actually measured electron fluxes at geostationary orbit. This model implies the multi-step particle acceleration and is based on numerical integrating two linked continuity equations for primarily accelerated particles and relativistic electrons. The model includes a source and losses, and used solar wind data as only input parameters. We used the coupling function which is a best-fit combination of solar wind/interplanetary magnetic field parameters, responsible for the generation of geomagnetic activity, as a source. The loss function was derived from experimental data. We tested the model for four year period 2004-2007. The correlation coefficient between predicted and actual values of the electron fluxes for whole four year period as well as for each of these years is stable and incredibly high (about 0.9). The high and stable correlation between the computed and actual electron fluxes shows that the reliable forecasting these electrons at geostationary orbit is possible.

  11. Five years in the life of an inertial system operating in orbit

    Science.gov (United States)

    Harris, R. A.; Denhard, W. G.

    1978-01-01

    The paper describes the in-orbit performance of the gyroscopes and strapdown attitude reference system for the OAO-C (Copernicus) satellite, launched on Aug. 21, 1972. In order to fulfill NASA requirements, the inertial system had to: (1) operate for at least one year in orbit without failure, (2) maintain an inertial reference with an uncertainty of 50 microradians or less for at least one hour, and (3) control attitude changes with an accuracy of at least 30 parts per million. During the orbit period, the inertial system has demonstrated a capability for maintaining an inertial reference that is significantly better than these performance goals.

  12. DNA typing from vaginal smear slides in suspected rape cases

    Directory of Open Access Journals (Sweden)

    Dayse Aparecida da Silva

    Full Text Available In an investigation of suspected rape, proof of sexual assault with penetration is required. In view of this, detailed descriptions of the genitalia, the thighs and pubic region are made within the forensic medical service. In addition, vaginal swabs are taken from the rape victim and some of the biological material collected is then transferred to glass slides. In this report, we describe two rape cases solved using DNA typing from cells recovered from vaginal smear slides. In 1999, two young women informed the Rio de Janeiro Police Department that they had been victims of sexual assaults. A suspect was arrested and the victims identified him as the offender. The suspect maintained that he was innocent. In order to elucidate these crimes, vaginal smear slides were sent to the DNA Diagnostic Laboratory for DNA analysis three months after the crimes, as unique forensic evidence. To get enough epithelial and sperm cells to perform DNA analysis, we used protocols modified from the previously standard protocols used for DNA extraction from biological material fixed on glass slides. The quantity of cells was sufficient to perform human DNA typing using nine short tandem repeat (STR loci. It was 3.3 billion times more probable that it was the examined suspect who had left sperm cells in the victims, rather than any other individual in the population of Rio de Janeiro.

  13. Science Planning and Orbit Classification for Solar Probe Plus

    Science.gov (United States)

    Kusterer, M. B.; Fox, N. J.; Rodgers, D. J.; Turner, F. S.

    2016-12-01

    There are a number of challenges for the Science Planning Team (SPT) of the Solar Probe Plus (SPP) Mission. Since SPP is using a decoupled payload operations approach, tight coordination between the mission operations and payload teams will be required. The payload teams must manage the volume of data that they write to the spacecraft solid-state recorders (SSR) for their individual instruments for downlink to the ground. Making this process more difficult, the geometry of the celestial bodies and the spacecraft during some of the SPP mission orbits cause limited uplink and downlink opportunities. The payload teams will also be required to coordinate power on opportunities, command uplink opportunities, and data transfers from instrument memory to the spacecraft SSR with the operation team. The SPT also intend to coordinate observations with other spacecraft and ground based systems. To solve these challenges, detailed orbit activity planning is required in advance for each orbit. An orbit planning process is being created to facilitate the coordination of spacecraft and payload activities for each orbit. An interactive Science Planning Tool is being designed to integrate the payload data volume and priority allocations, spacecraft ephemeris, attitude, downlink and uplink schedules, spacecraft and payload activities, and other spacecraft ephemeris. It will be used during science planning to select the instrument data priorities and data volumes that satisfy the orbit data volume constraints and power on, command uplink and data transfer time periods. To aid in the initial stages of science planning we have created an orbit classification scheme based on downlink availability and significant science events. Different types of challenges arise in the management of science data driven by orbital geometry and operational constraints, and this scheme attempts to identify the patterns that emerge.

  14. Diagnostic efficacy and therapeutic impact of computed tomography in the evaluation of clinically suspected otosclerosis

    International Nuclear Information System (INIS)

    Dudau, Cristina; Salim, Fakhruddin; Jiang, Dan; Connor, Steve E.J.

    2017-01-01

    To assess the diagnostic efficacy and therapeutic impact of CT in evaluating patients with clinically suspected otosclerosis. CT scans performed over a 5-year period for clinically suspected otosclerosis were retrospectively reviewed. CT diagnoses were correlated with subsequent surgical management. For otosclerosis positive cases, clinically significant extensions of otosclerosis were correlated with audiometry and the diagnosis was correlated with surgical findings. Of 259 CT studies, 46 % of patients were positive, 49 % negative and 5 % equivocal for otosclerosis. A relevant alternative CT diagnosis was evident in 33 % of the negative studies. One targeted surgery was performed for every four CT studies. CT outcome influenced the decision to perform stapedectomy in 41 % CT-positive versus 4 % CT-negative patients. CT-positive ears for otosclerosis could not be predicted from baseline clinical or audiometric criteria. Those with endosteal extension demonstrated lower bone conduction thresholds presurgically. The positive predictive value of CT diagnosis of otosclerosis was 100 %. CT demonstrated a high rate of clinically relevant diagnoses in both CT-positive and -negative for otosclerosis patients, and this frequently influenced surgical management. CT also added value by demonstrating relevant extensions of the otosclerotic foci, some of which were predictive of audiometric parameters. (orig.)

  15. Diagnostic efficacy and therapeutic impact of computed tomography in the evaluation of clinically suspected otosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Dudau, Cristina [King' s College Hospital NHS Foundation Trust, Department of Neuroradiology, London (United Kingdom); Salim, Fakhruddin; Jiang, Dan [Department of Otolaryngology, Head and Neck Surgery, Auditory Implantation Centre, London (United Kingdom); Connor, Steve E.J. [Department of Radiology, Guy' s and St Thomas' NHS Foundation Trust, London (United Kingdom)

    2017-03-15

    To assess the diagnostic efficacy and therapeutic impact of CT in evaluating patients with clinically suspected otosclerosis. CT scans performed over a 5-year period for clinically suspected otosclerosis were retrospectively reviewed. CT diagnoses were correlated with subsequent surgical management. For otosclerosis positive cases, clinically significant extensions of otosclerosis were correlated with audiometry and the diagnosis was correlated with surgical findings. Of 259 CT studies, 46 % of patients were positive, 49 % negative and 5 % equivocal for otosclerosis. A relevant alternative CT diagnosis was evident in 33 % of the negative studies. One targeted surgery was performed for every four CT studies. CT outcome influenced the decision to perform stapedectomy in 41 % CT-positive versus 4 % CT-negative patients. CT-positive ears for otosclerosis could not be predicted from baseline clinical or audiometric criteria. Those with endosteal extension demonstrated lower bone conduction thresholds presurgically. The positive predictive value of CT diagnosis of otosclerosis was 100 %. CT demonstrated a high rate of clinically relevant diagnoses in both CT-positive and -negative for otosclerosis patients, and this frequently influenced surgical management. CT also added value by demonstrating relevant extensions of the otosclerotic foci, some of which were predictive of audiometric parameters. (orig.)

  16. STATUS GIZI DAN STATUS IODIUM PADA BALITA DENGAN SUSPECT DOWN SYNDROME

    Directory of Open Access Journals (Sweden)

    Hastin Dyah K.

    2012-10-01

    Full Text Available Background: Nutritional status is one of the factor that determines the human resources and quality of life. Toddlers are one of vulnerable groups for nutritional problems. One of the nutrition problem in Indonesia is Iodine deficiency disorder. Clinical manifestations are not only endemic goiter and cretins, but also abortion, stillbirth, and congenital abnormalities. Congenital abnormalities are commonly found in areas ofendemic iodine deficiency disorder such as Down Syndrome. Objectives: This study aims to determine the iodine nutrition status of children under jive with Down Syndrome Suspect in endemic areas ofiodine deficiency disorder. Method: This research is descriptive study with cross sectional design. The study was conducted in Magelang district, which is endemic iodine deficiency disorder. Total sample of30 under jive years old with Down Syndrome Suspect. Result: The result showed that the nutritional status of respondents based on the weight/age index was 50% had good nutritional status. According to height/age index as much as 70% are short and very short. Based on weight/height index was 73,3% with normal nutritional status. At least 33% of children with Down Syndrome Suspect accompanied hypothyroidism.  Keywords: Suspect Down Syndrome, Nutritional Status, Iodine Status

  17. Semiclassical description of resonant tunnel effect: bifurcations and periodic orbits in the resonant current; Description semiclassique de l`effet tunnel resonant: bifurcations et orbites periodiques dans le courant resonant

    Energy Technology Data Exchange (ETDEWEB)

    Rouben, D C

    1997-11-28

    A semiclassical method for resonant tunneling in a quantum well in the presence of a magnetic field tilted with regard to an electric field is developed. In particular a semiclassical formula is derived for the total current of electrons after the second barrier of the quantum well. The contribution of the stable and unstable orbits is studied. It appears that the parameters which describe the classical chaos in the quantum well have an important effect on the tunneling current. A numerical experiment is led, the contributions to the current of some particular orbits are evaluated and the results are compared with those given by the quantum theory. (A.C.) 70 refs.

  18. A 3D Visualization and Analysis Model of the Earth Orbit, Milankovitch Cycles and Insolation.

    Science.gov (United States)

    Kostadinov, Tihomir; Gilb, Roy

    2013-04-01

    Milankovitch theory postulates that periodic variability of Earth's orbital elements is a major climate forcing mechanism. Although controversies remain, ample geologic evidence supports the major role of the Milankovitch cycles in climate, e.g. glacial-interglacial cycles. There are three Milankovitch orbital parameters: orbital eccentricity (main periodicities of ~100,000 and ~400,000 years), precession (quantified as the longitude of perihelion, main periodicities 19,000-24,000 years) and obliquity of the ecliptic (Earth's axial tilt, main periodicity 41,000 years). The combination of these parameters controls the spatio-temporal patterns of incoming solar radiation (insolation) and the timing of the seasons with respect to perihelion, as well as season duration. The complex interplay of the Milankovitch orbital parameters on various time scales makes assessment and visualization of Earth's orbit and insolation variability challenging. It is difficult to appreciate the pivotal importance of Kepler's laws of planetary motion in controlling the effects of Milankovitch cycles on insolation patterns. These factors also make Earth-Sun geometry and Milankovitch theory difficult to teach effectively. Here, an astronomically precise and accurate Earth orbit visualization model is presented. The model offers 3D visualizations of Earth's orbital geometry, Milankovitch parameters and the ensuing insolation forcings. Both research and educational uses are envisioned for the model, which is developed in Matlab® as a user-friendly graphical user interface (GUI). We present the user with a choice between the Berger et al. (1978) and Laskar et al. (2004) astronomical solutions for eccentricity, obliquity and precession. A "demo" mode is also available, which allows the three Milankovitch parameters to be varied independently of each other (and over much larger ranges than the naturally occurring ones), so the user can isolate the effects of each parameter on orbital geometry

  19. Suspecting Neurological Dysfunction From E Mail Messages ...

    African Journals Online (AJOL)

    A non medical person suspected and confirmed neurological dysfunction in an individual, based only on e mail messages sent by the individual. With email communication becoming rampant “peculiar” email messages may raise the suspicion of neurological dysfunction. Organic pathology explaining the abnormal email ...

  20. Charge-spin-orbital dynamics of one-dimensional two-orbital Hubbard model

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Hiroaki [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2010-01-15

    We study the real-time evolution of a charge-excited state in a one-dimensional e{sub g}-orbital degenerate Hubbard model, by a time-dependent density-matrix renormalization group method. Considering a chain along the z direction, electrons hop between adjacent 3z{sup 2}-r{sup 2} orbitals, while x{sup 2}-y{sup 2} orbitals are localized. For the charge-excited state, a holon-doublon pair is introduced into the ground state at quarter filling. At initial time, there is no electron in a holon site, while a pair of electrons occupies 3z{sup 2}-r{sup 2} orbital in a doublon site. As the time evolves, the holon motion is governed by the nearest-neighbor hopping, but the electron pair can transfer between 3z{sup 2}-r{sup 2} orbital and x{sup 2}-y{sup 2} orbital through the pair hopping in addition to the nearest-neighbor hopping. Thus holon and doublon propagate at different speed due to the pair hopping that is characteristic of multi-orbital systems.

  1. Reactivity index based on orbital energies.

    Science.gov (United States)

    Tsuneda, Takao; Singh, Raman K

    2014-05-30

    This study shows that the chemical reactivities depend on the orbital energy gaps contributing to the reactions. In the process where a reaction only makes progress through charge transfer with the minimal structural transformation of the reactant, the orbital energy gap gradient (OEGG) between the electron-donating and electron-accepting orbitals is proven to be very low. Using this relation, a normalized reaction diagram is constructed by plotting the normalized orbital energy gap with respect to the normalized intrinsic reaction coordinate. Application of this reaction diagram to 43 fundamental reactions showed that the majority of the forward reactions provide small OEGGs in the initial stages, and therefore, the initial processes of the forward reactions are supposed to proceed only through charge transfer. Conversely, more than 60% of the backward reactions are found to give large OEGGs implying very slow reactions associated with considerable structural transformations. Focusing on the anti-activation-energy reactions, in which the forward reactions have higher barriers than those of the backward ones, most of these reactions are shown to give large OEGGs for the backward reactions. It is also found that the reactions providing large OEGGs in the forward directions inconsistent with the reaction rate constants are classified into SN 2, symmetric, and methyl radical reactions. Interestingly, several large-OEGG reactions are experimentally established to get around the optimum pathways. This indicates that the reactions can take significantly different pathways from the optimum ones provided no charge transfer proceeds spontaneously without the structural transformations of the reactants. Copyright © 2014 Wiley Periodicals, Inc.

  2. Early Reconstruction of Orbital Roof Fractures: Clinical Features and Treatment Outcomes

    Directory of Open Access Journals (Sweden)

    Jin Woo Kim

    2012-01-01

    Full Text Available BackgroundOrbital roof fractures are frequently associated with a high energy impact to the craniofacial region, and displaced orbital roof fractures can cause ophthalmic and neurologic complications and occasionally require open surgical intervention. The purpose of this article was to investigate the clinical features and treatment outcomes of orbital root fractures combined with neurologic injuries after early reconstruction.MethodsBetween January 2006 and December 2008, 45 patients with orbital roof fractures were admitted; among them, 37 patients were treated conservatively and 8 patients underwent early surgical intervention for orbital roof fractures. The type of injuries that caused the fractures, patient characteristics, associated fractures, ocular and neurological injuries, patient management, and treatment outcomes were investigated.ResultsThe patients underwent frontal craniotomy and free bone fragment removal, their orbital roofs were reconstructed with titanium micromesh, and associated fractures were repaired. The mean follow up period was 11 months. There were no postoperative neurologic sequelae. Postoperative computed tomography scans showed anatomically reconstructed orbital roofs. Two of the five patients with traumatic optic neuropathy achieved full visual acuity recovery, one patient showed decreased visual acuity, and the other two patients completely lost their vision due to traumatic optic neuropathy. Preoperative ophthalmic symptoms, such as proptosis, diplopia, upper eyelid ptosis, and enophthalmos were corrected.ConclusionsEarly recognition and treatment of orbital roof fractures can reduce intracranial and ocular complications. A coronal flap with frontal craniotomy and orbital roof reconstruction using titanium mesh provides a versatile method and provides good functional and cosmetic results.

  3. ON THE ORBIT OF EXOPLANET WASP-12b

    International Nuclear Information System (INIS)

    Campo, Christopher J.; Harrington, Joseph; Hardy, Ryan A.; Stevenson, Kevin B.; Nymeyer, Sarah; Lust, Nate B.; Blecic, Jasmina; Britt, Christopher B. T.; Bowman, William C.; Ragozzine, Darin; Anderson, David R.; Hellier, Coel; Maxted, Pierre F. L.; Collier-Cameron, Andrew; Wheatley, Peter J.; Loredo, Thomas J.; Deming, Drake; Hebb, Leslie; Pollaco, Don; West, Richard G.

    2011-01-01

    We observed two secondary eclipses of the exoplanet WASP-12b using the Infrared Array Camera on the Spitzer Space Telescope. The close proximity of WASP-12b to its G-type star results in extreme tidal forces capable of inducing apsidal precession with a period as short as a few decades. This precession would be measurable if the orbit had a significant eccentricity, leading to an estimate of the tidal Love number and an assessment of the degree of central concentration in the planetary interior. An initial ground-based secondary-eclipse phase reported by Lopez-Morales et al. (0.510 ± 0.002) implied eccentricity at the 4.5σ level. The spectroscopic orbit of Hebb et al. has eccentricity 0.049 ± 0.015, a 3σ result, implying an eclipse phase of 0.509 ± 0.007. However, there is a well-documented tendency of spectroscopic data to overestimate small eccentricities. Our eclipse phases are 0.5010 ± 0.0006 (3.6 and 5.8 μm) and 0.5006 ± 0.0007 (4.5 and 8.0 μm). An unlikely orbital precession scenario invoking an alignment of the orbit during the Spitzer observations could have explained this apparent discrepancy, but the final eclipse phase of Lopez-Morales et al. (0.510 ± +0.007 -0.006 ) is consistent with a circular orbit at better than 2σ. An orbit fit to all the available transit, eclipse, and radial-velocity data indicates precession at <1σ; a non-precessing solution fits better. We also comment on analysis and reporting for Spitzer exoplanet data in light of recent re-analyses.

  4. Return to Venus of AKATSUKI, the Japanese Venus Orbiter

    Science.gov (United States)

    Nakamura, M.; Iwagami, N.; Satoh, T.; Taguchi, M.; Watanabe, S.; Takahashi, Y.; Imamura, T.; Suzuki, M.; Ueno, M.; Yamazaki, A.; Fukuhara, T.; Yamada, M.; Ishii, N.; Ogohara, K.

    2011-12-01

    Japanese Venus Climate Orbiter 'AKATSUKI' (PLANET-C) was proposed in 2001 with strong support by international Venus science community and approved as an ISAS mission soon after the proposal. AKATSUKI and ESA's Venus Express complement each other in Venus climate study. Various coordinated observations using the two spacecraft have been planned. Also participating scientists from US have been selected. Its science target is to understand the climate of Venus. The mission life we expected was more than 2 Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles' expansion was confirmed. AKATSUKI was put into the 3-axis stabilized mode in the initial operation from Uchinoura station and the critical operation was finished at 20:00JST on the same day. The malfunction, which happened during the Venus Orbit Insertion (VOI) on7 Dec, 2010 is as follows. We set all commands on Dec. 5. Attitude control for Venus orbit insertion (VOI) was automatically done on Dec. 6. Orbital maneuver engine (OME) was fired 08:49 JST on Dec. 7. 1min. after firing the spacecraft went into the occultation region and we had no telemetry, but we expected to continuous firing for 12min. Recording on the spacecraft told us later that, unfortunately the firing continued just 152sec. and stopped. The reason of the malfunction of the OME was the blocking of check valve of the gas pressure line to push the fuel to the engine. We failed to make the spacecraft the Venus orbiter, and it is rotating the sun with the orbital period of 203 days. As the Venus orbit the sun with the period of 225 days, AKATSUKI has a chance to meet Venus again in 5 or 6 years depending on the orbit correction plan. Let us summarize the present situation of AKATSUKI. Most of the fuel still remains. But the condition of the propulsion

  5. Improving the Yield of Histological Sampling in Patients With Suspected Colorectal Cancer During Colonoscopy by Introducing a Colonoscopy Quality Assurance Program.

    Science.gov (United States)

    Gado, Ahmed; Ebeid, Basel; Abdelmohsen, Aida; Axon, Anthony

    2011-08-01

    Masses discovered by clinical examination, imaging or endoscopic studies that are suspicious for malignancy typically require biopsy confirmation before treatment is initiated. Biopsy specimens may fail to yield a definitive diagnosis if the lesion is extensively ulcerated or otherwise necrotic and viable tumor tissue is not obtained on sampling. The diagnostic yield is improved when multiple biopsy samples (BSs) are taken. A colonoscopy quality-assurance program (CQAP) was instituted in 2003 in our institution. The aim of this study was to determine the effect of instituting a CQAP on the yield of histological sampling in patients with suspected colorectal cancer (CRC) during colonoscopy. Initial assessment of colonoscopy practice was performed in 2003. A total of five patients with suspected CRC during colonoscopy were documented in 2003. BSs confirmed CRC in three (60%) patients and were nondiagnostic in two (40%). A quality-improvement process was instituted which required a minimum six BSs with adequate size of the samples from any suspected CRC during colonoscopy. A total of 37 patients for the period 2004-2010 were prospectively assessed. The diagnosis of CRC was confirmed with histological examination of BSs obtained during colonoscopy in 63% of patients in 2004, 60% in 2005, 50% in 2006, 67% in 2007, 100% in 2008, 67% in 2009 and 100% in 2010. The yield of histological sampling increased significantly ( p quality assurance and improvement program increased the yield of histological sampling in patients with suspected CRC during colonoscopy.

  6. A period-doubling cascade precedes chaos for planar maps.

    Science.gov (United States)

    Sander, Evelyn; Yorke, James A

    2013-09-01

    A period-doubling cascade is often seen in numerical studies of those smooth (one-parameter families of) maps for which as the parameter is varied, the map transitions from one without chaos to one with chaos. Our emphasis in this paper is on establishing the existence of such a cascade for many maps with phase space dimension 2. We use continuation methods to show the following: under certain general assumptions, if at one parameter there are only finitely many periodic orbits, and at another parameter value there is chaos, then between those two parameter values there must be a cascade. We investigate only families that are generic in the sense that all periodic orbit bifurcations are generic. Our method of proof in showing there is one cascade is to show there must be infinitely many cascades. We discuss in detail two-dimensional families like those which arise as a time-2π maps for the Duffing equation and the forced damped pendulum equation.

  7. A Risk Prediction Model for In-hospital Mortality in Patients with Suspected Myocarditis.

    Science.gov (United States)

    Xu, Duo; Zhao, Ruo-Chi; Gao, Wen-Hui; Cui, Han-Bin

    2017-04-05

    Myocarditis is an inflammatory disease of the myocardium that may lead to cardiac death in some patients. However, little is known about the predictors of in-hospital mortality in patients with suspected myocarditis. Thus, the aim of this study was to identify the independent risk factors for in-hospital mortality in patients with suspected myocarditis by establishing a risk prediction model. A retrospective study was performed to analyze the clinical medical records of 403 consecutive patients with suspected myocarditis who were admitted to Ningbo First Hospital between January 2003 and December 2013. A total of 238 males (59%) and 165 females (41%) were enrolled in this study. We divided the above patients into two subgroups (survival and nonsurvival), according to their clinical in-hospital outcomes. To maximize the effectiveness of the prediction model, we first identified the potential risk factors for in-hospital mortality among patients with suspected myocarditis, based on data pertaining to previously established risk factors and basic patient characteristics. We subsequently established a regression model for predicting in-hospital mortality using univariate and multivariate logistic regression analyses. Finally, we identified the independent risk factors for in-hospital mortality using our risk prediction model. The following prediction model for in-hospital mortality in patients with suspected myocarditis, including creatinine clearance rate (Ccr), age, ventricular tachycardia (VT), New York Heart Association (NYHA) classification, gender and cardiac troponin T (cTnT), was established in the study: P = ea/(1 + ea) (where e is the exponential function, P is the probability of in-hospital death, and a = -7.34 + 2.99 × [Ccr model demonstrated that a Ccr prediction model for in-hospital mortality in patients with suspected myocarditis. In addition, sufficient life support during the early stage of the disease might improve the prognoses of patients with

  8. [Characteristics of communication systems of suspected occupational disease in the Autonomous Communities, Spain].

    Science.gov (United States)

    García Gómez, Montserrat; Urbaneja Arrúe, Félix; García López, Vega; Estaban Buedo, Valentín; Rodríguez Suárez, Valentín; Miralles Martínez-Portillo, Lourdes; González García, Isabel; Egea Garcia, Josefa; Corraliza Infanzon, Emma; Ramírez Salvador, Laura; Briz Blázquez, Santiago; Armengol Rosell, Ricard; Cisnal Gredilla, José María; Correa Rodríguez, Juan Francisco; Coto Fernández, Juan Carlos; Díaz Peral, Mª Rosario; Elvira Espinosa, Mercedes; Fernández Fernández, Iñigo; García-Ramos Alonso, Eduardo; Martínez Arguisuelas, Nieves; Rivas Pérez, Ana Isabel

    2017-03-17

    There are several initiatives to develop systems for the notification of suspected occupational disease (OD) in different autonomous communities. The objective was to describe the status of development and characteristics of these systems implemented by the health authorities. A cross-sectional descriptive study was carried out on the existence of systems for the information and surveillance of suspected OD, their legal framework, responsible institution and availability of information. A specific meeting was held and a survey was designed and sent to all autonomous communities and autonomous cities (AACC). Information was collected on the existence of a regulatory standard, assigned human resources, notifiers, coverage and number of suspected OD received, processed and recognized. 18 of 19 AACC responded. 10 have developed a suspected OD notification system, 3 of them supported by specific autonomic law. The notifiers were physicians of the public health services, physicians of the occupational health services and, in 2 cases, medical inspectors. 7 AACC had specific software to support the system. The OD recognition rate of suspected cases was 53% in the Basque Country; 41% in Castilla-La Mancha; 36% in Murcia; 32.6% in the Valencian Community and 31% in La Rioja. The study has revealed an heterogeneous development of suspected OD reporting systems in Spain. Although the trend is positive, only 55% of the AACC have some type of development and 39% have specific software supporting it. Therefore unequal OD recognition rates have been obtained depending on the territory.

  9. NICER Discovers the Ultracompact Orbit of the Accreting Millisecond Pulsar IGR J17062–6143

    Science.gov (United States)

    Strohmayer, T. E.; Arzoumanian, Z.; Bogdanov, S.; Bult, P. M.; Chakrabarty, D.; Enoto, T.; Gendreau, K. C.; Guillot, S.; Harding, A. K.; Ho, W. C. G.; Homan, J.; Jaisawal, G. K.; Keek, L.; Kerr, M.; Mahmoodifar, S.; Markwardt, C. B.; Ransom, S. M.; Ray, P. S.; Remillard, R.; Wolff, M. T.

    2018-05-01

    We present results of recent Neutron Star Interior Composition Explorer (NICER) observations of the accreting millisecond X-ray pulsar (AMXP) IGR J17062‑6143 that show that it resides in a circular, ultracompact binary with a 38-minute orbital period. NICER observed the source for ≈26 ks over a 5.3-day span in 2017 August, and again for 14 and 11 ks in 2017 October and November, respectively. A power spectral analysis of the August exposure confirms the previous detection of pulsations at 163.656 Hz in Rossi X-ray Timing Explorer (RXTE) data, and reveals phase modulation due to orbital motion of the neutron star. A coherent search for the orbital solution using the Z 2 method finds a best-fitting circular orbit with a period of 2278.21 s (37.97 minutes), a projected semimajor axis of 0.00390 lt-s, and a barycentric pulsar frequency of 163.6561105 Hz. This is currently the shortest known orbital period for an AMXP. The mass function is 9.12 × 10‑8 M ⊙, presently the smallest known for a stellar binary. The minimum donor mass ranges from ≈0.005 to 0.007 M ⊙ for a neutron star mass from 1.2 to 2 M ⊙. Assuming mass transfer is driven by gravitational radiation, we find donor mass and binary inclination bounds of 0.0175–0.0155 M ⊙ and 19° < i < 27.°5, where the lower and upper bounds correspond to 1.4 and 2 M ⊙ neutron stars, respectively. Folding the data accounting for the orbital modulation reveals a sinusoidal profile with fractional amplitude 2.04 ± 0.11% (0.3–3.2 keV).

  10. Improving BDS Autonomous Orbit Determination Performance Using Onboard Accelerometers

    Directory of Open Access Journals (Sweden)

    QIAO Jing

    2017-05-01

    achieved over a service life of two months using SST data and accelerometers. If only SST data are used, the orbit accuracy is 3~6 m with the same time period, which is an order worse.

  11. The Lawyer in the Dutch Interrogation Room: Influence on Police and Suspect

    NARCIS (Netherlands)

    W-J. Verhoeven (Willem-Jan); L. Stevens (Lonneke)

    2012-01-01

    textabstractIn many European countries, providing a suspect in custody with legal aid before the first police interrogation is a heavily debated issue. In this paper, we report on an exploratory study on the use of coercion by the police and the use of the right to silence by suspects in 70 Dutch

  12. Electron orbits in the microwave inverse FEL accelerator (MIFELA)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T.B.; Marshall, T.C. [Columbia Univ., New York, NY (United States)

    1995-12-31

    The MIFELA is a new device based on stimulated absorption of microwaves by electrons moving along an undulator. An intense microwave field is used (a{sub s} = eE{sub s}/k{sub s} m c{sup 2} = 0.2) as well as a large undulator field (a{sub w}/{gamma} = eB{sub {perpendicular}}/{gamma}k{sub w} mc{sup 2} = 1/2) to accelerate electrons emitted at 6MeV from a rf gun to 20MeV in 1.5m. The spiral radius of the electrons in the undulator is 8mm, in a waveguide of diameter 34mm, with undulator period about 10cm. There is a small guiding field, and the electrons move in type I orbits. We describe three problems connected with the orbital motion of the electrons in this structure: (i) injecting the electrons in an increasing undulator field prior to entering the MIFELA; (ii) orbital motion and stability inside the MIFELA; (iii) extraction of electrons from the spiral orbit in the accelerator into an axially-propagating beam, obtaining {Beta}{sub {perpendicular}} < 0.02. These studies have application to a MIFELA which is under construction at Yale University by Omega-P.

  13. Traumatic orbital CSF leak

    Science.gov (United States)

    Borumandi, Farzad

    2013-01-01

    Compared to the cerebrospinalfluid (CSF) leak through the nose and ear, the orbital CSF leak is a rare and underreported condition following head trauma. We present the case of a 49-year-old woman with oedematous eyelid swelling and ecchymosis after a seemingly trivial fall onto the right orbit. Apart from the above, she was clinically unremarkable. The CT scan revealed a minimally displaced fracture of the orbital roof with no emphysema or intracranial bleeding. The fractured orbital roof in combination with the oedematous eyelid swelling raised the suspicion for orbital CSF leak. The MRI of the neurocranium demonstrated a small-sized CSF fistula extending from the anterior cranial fossa to the right orbit. The patient was treated conservatively and the lid swelling resolved completely after 5 days. Although rare, orbital CSF leak needs to be included in the differential diagnosis of periorbital swelling following orbital trauma. PMID:24323381

  14. A0535+26: Refined position measurement and new pulse period data

    International Nuclear Information System (INIS)

    Li, F.; Rappaport, S.; Clark, G.W.; Jernigan, J.G.

    1979-01-01

    The hard, pulsing, transient X-ray source A0535+26 has been observed with SAS 3 on three occasions during 1977--1978. These observations have yielded a precise position measurement (20'' error radius) which renders the identification of A0535+26 with the Be star HDE 245770 virtually certain. The pulse phase was tracked for approx.9 days in 1978 April and clearly showed both first and second derivatives in the pulse period. An analysis of these new timing data, combined with data from previous observations, leads to the following conclusions: (1) a significant fraction of the observed changes in pulse period is probably intrinsic to the compact X-ray stae (e.g., accretion torques on a neutron star), and (2) conservative limits on binary orbital parameters tend to further confirm a long orbital period

  15. Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?

    International Nuclear Information System (INIS)

    Theophilou, Iris; Helbig, Nicole; Lathiotakis, Nektarios N.; Gidopoulos, Nikitas I.; Rubio, Angel

    2015-01-01

    Recently, an approximate theoretical framework was introduced, called local reduced density matrix functional theory (local-RDMFT), where functionals of the one-body reduced density matrix (1-RDM) are minimized under the additional condition that the optimal orbitals satisfy a single electron Schrödinger equation with a local potential. In the present work, we focus on the character of these optimal orbitals. In particular, we compare orbitals obtained by local-RDMFT with those obtained with the full minimization (without the extra condition) by contrasting them against the exact NOs and orbitals from a density functional calculation using the local density approximation (LDA). We find that the orbitals from local-RMDFT are very close to LDA orbitals, contrary to those of the full minimization that resemble the exact NOs. Since local RDMFT preserves the good quality of the description of strong static correlation, this finding opens the way to a mixed density/density matrix scheme, where Kohn-Sham orbitals obtain fractional occupations from a minimization of the occupation numbers using 1-RDM functionals. This will allow for a description of strong correlation at a cost only minimally higher than a density functional calculation

  16. A Spectroscopic Orbit for the Late-type Be Star β CMi

    Energy Technology Data Exchange (ETDEWEB)

    Dulaney, Nicholas A.; Richardson, Noel D.; Gerhartz, Cody J.; Bjorkman, J. E.; Bjorkman, K. S.; Morrison, Nancy D.; Bratcher, Allison D.; Greco, Jennifer J.; Hardegree-Ullman, Kevin K.; Lembryk, Ludwik; Oswald, Wayne L.; Trucks, Jesica L. [Ritter Observatory, Department of Physics and Astronomy, The University of Toledo, Toledo, OH 43606-3390 (United States); Carciofi, Alex C. [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, SP 05508-900 (Brazil); Klement, Robert [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago (Chile); Wang, Luqian, E-mail: noel.richardson@UToledo.edu [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States)

    2017-02-10

    The late-type Be star β CMi is remarkably stable compared to other Be stars that have been studied. This has led to a realistic model of the outflowing Be disk by Klement et al. These results showed that the disk is likely truncated at a finite radius from the star, which Klement et al. suggest is evidence for an unseen binary companion in orbit. Here we report on an analysis of the Ritter Observatory spectroscopic archive of β CMi to search for evidence of the elusive companion. We detect periodic Doppler shifts in the wings of the H α line with a period of 170 days and an amplitude of 2.25 km s{sup −1}, consistent with a low-mass binary companion ( M ≈ 0.42 M {sub ⊙}). We then compared small changes in the violet-to-red peak height changes ( V / R ) with the orbital motion. We find weak evidence that it does follow the orbital motion, as suggested by recent Be binary models by Panoglou et al. Our results, which are similar to those for several other Be stars, suggest that β CMi may be a product of binary evolution where Roche lobe overflow has spun up the current Be star, likely leaving a hot subdwarf or white dwarf in orbit around the star. Unfortunately, no direct sign of this companion star is found in the very limited archive of International Ultraviolet Explorer spectra.

  17. Orbital parameters of the multiple system EM Boo

    Science.gov (United States)

    Özkardeş, B.; Bakış, H.; Bakış, V.

    2018-02-01

    EM Boo is a relatively bright (V = 8.98 mag.) and short orbital period (P⁓2.45 days) binary star member of the multiple system WDS J14485+2445AB. There is neither photometric nor spectroscopic study of the system in the literature. In this work, we obtained spectroscopic orbital parameters of the system from new high resolution spectroscopic observations made with échelle spectrograph attached to UBT60 telescope of Akdeniz University. The spectroscopic solution yielded the values K1 = 100.7±2.6 km/s, K2 = 120.1±2.6 km/s and Vγ = -14.6±3.1 km/s, and thus the mass ratio of the system q = 0.838±0.064.

  18. INFRARED SPECTROSCOPY OF SYMBIOTIC STARS. VIII. ORBITS FOR THREE S-TYPE SYSTEMS: AE ARAE, Y CORONAE AUSTRALIS, AND SS 73-147

    International Nuclear Information System (INIS)

    Fekel, Francis C.; Hinkle, Kenneth H.; Joyce, Richard R.; Wood, Peter R.

    2010-01-01

    With new infrared radial velocities we have computed orbits of the M giants in three southern S-type symbiotic systems. AE Ara and SS 73-147 have circular orbits with periods of 803 and 820 days, respectively. The eccentric orbit of Y CrA has a period that is about twice as long, 1619 days. Except for CH Cyg it is currently the S-type symbiotic system with the longest period for which a spectroscopic orbit has been determined. The Paschen δ emission line velocities of AE Ara are nearly in antiphase with the M giant absorption feature velocities and result in a mass ratio of 2.7. Emission lines in the 1.005 μm region for the other two symbiotic systems are not good proxies for the hot components in those systems. There is no evidence that these three symbiotics are eclipsing. With spectral classes of M5.5 or M6, the three giants presumably also have velocity variations that result from pulsations, but we have been unable to identify specific pulsation periods in the absorption line velocity residuals.

  19. Identification of novel micropollutants in wastewater by a combination of suspect and nontarget screening

    International Nuclear Information System (INIS)

    Hug, Christine; Ulrich, Nadin; Schulze, Tobias; Brack, Werner; Krauss, Martin

    2014-01-01

    To detect site-specific, suspected and formerly unknown contaminants in a wastewater treatment plant effluent, we established a screening procedure based on liquid chromatography–high resolution mass spectrometry (LC–HRMS) with stepwise identification schemes. Based on automated substructure searches a list of 2160 suspected site-specific and documented water contaminants was reduced to those amenable to LC–HRMS. After searching chromatograms for exact masses of suspects, presumably false positive detections were stepwise excluded by retention time prediction, the evaluation of isotope patterns, ionization behavior, and HRMS/MS spectra. In nontarget analysis, peaks for identification were selected based on distinctive isotope patterns and intensity. The stepwise identification of nontarget compounds was automated by a plausibility check of molecular formulas using the Seven Golden Rules, an exclusion of compounds with presumably low commercial importance and an automated HRMS/MS evaluation. Six suspected and five nontarget chemicals were identified, of which two have not been previously reported as environmental pollutants. -- Highlights: • A LC–HRMS-based suspect and nontarget screening was applied to wastewater. • Manual data processing to identify candidate structures was accelerated by automated software-based procedure. • Identification was supported by sophisticated analytical methods such as deuterium exchange. • Eleven site-specific and formerly unknown compounds were identified. • We provide a framework to extend analytical procedures from target to suspect and nontarget compounds. -- A screening procedure based on liquid chromatography–high resolution mass spectrometry (LC–HRMS) with a systematic data evaluation was established, which allowed detecting suspected and formerly unknown contaminants in wastewater

  20. Field theoretic approach to dynamical orbital localization in ab initio molecular dynamics

    International Nuclear Information System (INIS)

    Thomas, Jordan W.; Iftimie, Radu; Tuckerman, Mark E.

    2004-01-01

    Techniques from gauge-field theory are employed to derive an alternative formulation of the Car-Parrinello ab initio molecular-dynamics method that allows maximally localized Wannier orbitals to be generated dynamically as the calculation proceeds. In particular, the Car-Parrinello Lagrangian is mapped onto an SU(n) non-Abelian gauge-field theory and the fictitious kinetic energy in the Car-Parrinello Lagrangian is modified to yield a fully gauge-invariant form. The Dirac gauge-fixing method is then employed to derive a set of equations of motion that automatically maintain orbital locality by restricting the orbitals to remain in the 'Wannier gauge'. An approximate algorithm for integrating the equations of motion that is stable and maintains orbital locality is then developed based on the exact equations of motion. It is shown in a realistic application (64 water molecules plus one hydrogen-chloride molecule in a periodic box) that orbital locality can be maintained with only a modest increase in CPU time. The ability to keep orbitals localized in an ab initio molecular-dynamics calculation is a crucial ingredient in the development of emerging linear scaling approaches

  1. Application of low dose multi-slice helical CT in orbital trauma patients

    International Nuclear Information System (INIS)

    Yang Rui; Dai Limei; Li Jianying; Wang Fengyan; Du Guoquan

    2010-01-01

    Objective: To investigate the most appropriate low radiation dose in multi-slice CT (MSCT) scans for orbital trauma patients. Methods: Thirty trauma patients with suspected orbital fractures who underwent helical CT scans with a 64-MSCT using regular dose were selected. Noise was artificially introduced to the axial images using an image space noise addition tool to simulate 6 sets of lower dose scans with tube current of 30, 70, 100, 140, 170 and 200 mA, respectively. The lowest tube current with adequate image quality for confident diagnosis was determined based on the evaluation of the overall image quality and fracture detection on images at different dose levels. The determined lowest tube current was then validated using clinical scans. Radiation dose related parameters CTDIvol, DLP, ED were also recorded. Image quality was evaluated according to its low-density resolution, noise and structure clarity and characterized into 5-grades of excellent, good, fair, worse and worst. Rank sum test and χ 2 test were used for statistics. Results: In 30 trauma patients with regular dose of 300 mA, there were 30 cases of orbital fracture, 19 cases of intraorbital emphysema, 12 cases of ocular muscle injury and 1 case of intraorbital foreign body. These changes could still be clearly observed and correctly diagnosed when the tube current was reduced to as low as 70 mA. However, the overall image quality was mostly fair. At the simulated dose of 100 mA, the majority of images were characterized as excellent or good, and there was no statistical difference compared with that of regular dose scans (P>0.05). In the clinical evaluation for 20 orbital trauma patients with the reduced tube current of 100 m A , the majority of images were judged to be excellent (9 cases) or good (17 cases) and fair (4 cases). The radiation dose (0.29 mSv) was reduced by 70% compared with that of regular tube current of 300 mA (0.86 mSv). Conclusion: The tube current of MSCT may be used as low as

  2. Astrophysical parameters and orbital solution of the peculiar X-ray transient IGR J00370+6122

    Science.gov (United States)

    González-Galán, A.; Negueruela, I.; Castro, N.; Simón-Díaz, S.; Lorenzo, J.; Vilardell, F.

    2014-06-01

    Context. BD + 60° 73 is the optical counterpart of the X-ray source IGR J00370+6122, a probable accretion-powered X-ray pulsar. The X-ray light curve of this binary system shows clear periodicity at 15.7 d, which has been interpreted as repeated outbursts around the periastron of an eccentric orbit. Aims: We aim to characterise the binary system IGR J00370+6122 by deriving its orbital and physical parameters. Methods: We obtained high-resolution spectra of BD + 60° 73 at different epochs. We used the fastwind code to generate a stellar atmosphere model to fit the observed spectrum and obtain physical magnitudes. The synthetic spectrum was used as a template for cross-correlation with the observed spectra to measure radial velocities. The radial velocity curve provided an orbital solution for the system. We also analysed the RXTE/ASM and Swift/BAT light curves to confirm the stability of the periodicity. Results: BD + 60° 73 is a BN0.7 Ib low-luminosity supergiant located at a distance ~3.1 kpc, in the Cas OB4 association. We derive Teff = 24 000 K and log gc = 3.0, and chemical abundances consistent with a moderately high level of evolution. The spectroscopic and evolutionary masses are consistent at the 1-σ level with a mass M∗ ≈ 15 M⊙. The recurrence time of the X-ray flares is the orbital period of the system. The neutron star is in a high-eccentricity (e = 0.56 ± 0.07) orbit, and the X-ray emission is strongly peaked around orbital phase φ = 0.2, though the observations are consistent with some level of X-ray activity happening at all orbital phases. Conclusions: The X-ray behaviour of IGR J00370+6122 is reminiscent of "intermediate" supergiant X-ray transients, though its peak luminosity is rather low. The orbit is somewhat wider than those of classical persistent supergiant X-ray binaries, which when combined with the low luminosity of the mass donor, explains the low X-ray luminosity. IGR J00370+6122 will very likely evolve towards a persistent

  3. Proper Motion and Secular Variations of Keplerian Orbital Elements

    Directory of Open Access Journals (Sweden)

    Alexey G. Butkevich

    2018-05-01

    Full Text Available High-precision observations require accurate modeling of secular changes in the orbital elements in order to extrapolate measurements over long time intervals, and to detect deviation from pure Keplerian motion caused, for example, by other bodies or relativistic effects. We consider the evolution of the Keplerian elements resulting from the gradual change of the apparent orbit orientation due to proper motion. We present rigorous formulae for the transformation of the orbit inclination, longitude of the ascending node and argument of the pericenter from one epoch to another, assuming uniform stellar motion and taking radial velocity into account. An approximate treatment, accurate to the second-order terms in time, is also given. The proper motion effects may be significant for long-period transiting planets. These theoretical results are applicable to the modeling of planetary transits and precise Doppler measurements as well as analysis of pulsar and eclipsing binary timing observations.

  4. PERIODIC VARIABILITY OF LOW-MASS STARS IN SLOAN DIGITAL SKY SURVEY STRIPE 82

    International Nuclear Information System (INIS)

    Becker, A. C.; Hawley, S. L.; Ivezic, Z.; Kowalski, A. F.; Sesar, B.; Bochanski, J. J.; West, A. A.

    2011-01-01

    We present a catalog of periodic stellar variability in the 'Stripe 82' region of the Sloan Digital Sky Survey. After aggregating and re-calibrating catalog-level data from the survey, we ran a period-finding algorithm (Supersmoother) on all point-source light curves. We used color selection to identify systems that are likely to contain low-mass stars, in particular M dwarfs and white dwarfs. In total, we found 207 candidates, the vast majority of which appear to be in eclipsing binary systems. The catalog described in this paper includes 42 candidate M dwarf/white dwarf pairs, four white dwarf pairs, 59 systems whose colors indicate they are composed of two M dwarfs and whose light-curve shapes suggest they are in detached eclipsing binaries, and 28 M dwarf systems whose light-curve shapes suggest they are in contact binaries. We find no detached systems with periods longer than 3 days, thus the majority of our sources are likely to have experienced orbital spin-up and enhanced magnetic activity. Indeed, 26 of 27 M dwarf systems that we have spectra for show signs of chromospheric magnetic activity, far higher than the 24% seen in field stars of the same spectral type. We also find binaries composed of stars that bracket the expected boundary between partially and fully convective interiors, which will allow the measurement of the stellar mass-radius relationship across this transition. The majority of our contact systems have short orbital periods, with small variance (0.02 days) in the sample near the observed cutoff of 0.22 days. The accumulation of these stars at short orbital period suggests that the process of angular momentum loss, leading to period evolution, becomes less efficient at short periods. These short-period systems are in a novel regime for studying the effects of orbital spin-up and enhanced magnetic activity, which are thought to be the source of discrepancies between mass-radius predictions and measurements of these properties in eclipsing

  5. OTORHINOLARYNGOLOGICAL DISEASES MASQUERADING AS ORBITAL TUMOURS

    Directory of Open Access Journals (Sweden)

    Sharmistha Behera

    2017-09-01

    Full Text Available BACKGROUND The close proximity of the orbit and the paranasal sinuses, both of which share more than two-thirds of common walls makes the orbit too susceptible to infections spreading from the paranasal sinuses. In any case of proptosis indicating an orbital tumour, extension from a PNS lesion should be ruled out. MATERIALS AND METHODS The study was a retrospective descriptive study. Data taken from the patient's medical record during the period of July 2014- June 2017. A total of 32 cases of proptosis were studied all of which were secondary to paranasal sinus pathology. These cases were subject to routine clinical examination and investigations including CT and MRI scan. Histopathological diagnosis was obtained by biopsy in appropriate cases. RESULTS Out of 32 patients, males were 68.75% (n=22 and females were 31.25% (n=10. The largest age group are in the age range 41-50 years (31.25%, n=10 and in age group 0-10 years (31.25%. Out of the whole, 13 (40.6% of them were due to sinusitis, 6 (18.75% due to sinonasal malignancy, all of which were histopathologically confirmed to be squamous cell carcinoma of maxillary sinus, 6 (18.75% cases were of mucoceles from frontoethmoidal origin, 4 (12.50% cases were of fibrous dysplasia of maxillary sinus, 2 (6.25% case was of schwannoma of frontal sinus origin and 1 (3.12% case of Langerhans cell histiocytosis of maxillary sinus. In our study, proptosis was commonest presenting complaint in all 32 patients followed by nasal obstruction (62.5%, reduced vision (25%, facial asymmetry (25%, redness of eye (18.75% and double vision (12.50%. Out of all investigative modalities, biopsy was found to be the most accurate followed by CT scan brain, PNS and orbit. CONCLUSION Due to close proximity, nasal and PNS diseases through bone erosion or preformed pathways can invade the orbit and cause proptosis. Longstanding optic nerve compression by orbital encroachment of PNS lesion can lead to blindness due to optic

  6. EXTRACTING PERIODIC TRANSIT SIGNALS FROM NOISY LIGHT CURVES USING FOURIER SERIES

    Energy Technology Data Exchange (ETDEWEB)

    Samsing, Johan [Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States)

    2015-07-01

    We present a simple and powerful method for extracting transit signals associated with a known transiting planet from noisy light curves. Assuming the orbital period of the planet is known and the signal is periodic, we illustrate that systematic noise can be removed in Fourier space at all frequencies by only using data within a fixed time frame with a width equal to an integer number of orbital periods. This results in a reconstruction of the full transit signal, which on average is unbiased despite no prior knowledge of either the noise or the transit signal itself being used in the analysis. The method therefore has clear advantages over standard phase folding, which normally requires external input such as nearby stars or noise models for removing systematic components. In addition, we can extract the full orbital transit signal (360°) simultaneously, and Kepler-like data can be analyzed in just a few seconds. We illustrate the performance of our method by applying it to a dataset composed of light curves from Kepler with a fake injected signal emulating a planet with rings. For extracting periodic transit signals, our presented method is in general the optimal and least biased estimator and could therefore lead the way toward the first detections of, e.g., planet rings and exo-trojan asteroids.

  7. Antisymmetric Orbit Functions

    Directory of Open Access Journals (Sweden)

    Anatoliy Klimyk

    2007-02-01

    Full Text Available In the paper, properties of antisymmetric orbit functions are reviewed and further developed. Antisymmetric orbit functions on the Euclidean space $E_n$ are antisymmetrized exponential functions. Antisymmetrization is fulfilled by a Weyl group, corresponding to a Coxeter-Dynkin diagram. Properties of such functions are described. These functions are closely related to irreducible characters of a compact semisimple Lie group $G$ of rank $n$. Up to a sign, values of antisymmetric orbit functions are repeated on copies of the fundamental domain $F$ of the affine Weyl group (determined by the initial Weyl group in the entire Euclidean space $E_n$. Antisymmetric orbit functions are solutions of the corresponding Laplace equation in $E_n$, vanishing on the boundary of the fundamental domain $F$. Antisymmetric orbit functions determine a so-called antisymmetrized Fourier transform which is closely related to expansions of central functions in characters of irreducible representations of the group $G$. They also determine a transform on a finite set of points of $F$ (the discrete antisymmetric orbit function transform. Symmetric and antisymmetric multivariate exponential, sine and cosine discrete transforms are given.

  8. Angles-only relative orbit determination in low earth orbit

    Science.gov (United States)

    Ardaens, Jean-Sébastien; Gaias, Gabriella

    2018-06-01

    The paper provides an overview of the angles-only relative orbit determination activities conducted to support the Autonomous Vision Approach Navigation and Target Identification (AVANTI) experiment. This in-orbit endeavor was carried out by the German Space Operations Center (DLR/GSOC) in autumn 2016 to demonstrate the capability to perform spaceborne autonomous close-proximity operations using solely line-of-sight measurements. The images collected onboard have been reprocessed by an independent on-ground facility for precise relative orbit determination, which served as ultimate instance to monitor the formation safety and to characterize the onboard navigation and control performances. During two months, several rendezvous have been executed, generating a valuable collection of images taken at distances ranging from 50 km to only 50 m. Despite challenging experimental conditions characterized by a poor visibility and strong orbit perturbations, angles-only relative positioning products could be continuously derived throughout the whole experiment timeline, promising accuracy at the meter level during the close approaches. The results presented in the paper are complemented with former angles-only experience gained with the PRISMA satellites to better highlight the specificities induced by different orbits and satellite designs.

  9. Orbital fractures: a review

    Directory of Open Access Journals (Sweden)

    Jeffrey M Joseph

    2011-01-01

    Full Text Available Jeffrey M Joseph, Ioannis P GlavasDivision of Ophthalmic Plastic and Reconstructive Surgery, Department of Ophthalmology, School of Medicine, New York University, New York, NY, USA; Manhattan Eye, Ear, and Throat Hospital, New York, NY, USAAbstract: This review of orbital fractures has three goals: 1 to understand the clinically relevant orbital anatomy with regard to periorbital trauma and orbital fractures, 2 to explain how to assess and examine a patient after periorbital trauma, and 3 to understand the medical and surgical management of orbital fractures. The article aims to summarize the evaluation and management of commonly encountered orbital fractures from the ophthalmologic perspective and to provide an overview for all practicing ophthalmologists and ophthalmologists in training.Keywords: orbit, trauma, fracture, orbital floor, medial wall, zygomatic, zygomatic complex, zmc fracture, zygomaticomaxillary complex fractures 

  10. Characterization of Orbital Debris Photometric Properties Derived from Laboratory-Based Measurements

    Science.gov (United States)

    Cowardin, H.; Abercromby, K.; Barker, E.; Seitzer, P.; Schildknecht, T.

    2010-01-01

    To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC attempts to emulate illumination conditions seen in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC uses a 75 Watt Xenon arc lamp as a solar simulator, an SBIG CCD camera with standard Johnson/Bessel filters, and a robotic arm to simulate an object's position and rotation. The laboratory uses known shapes, materials suspected to be consistent with the orbital debris population, and three phase angles to best match the lighting conditions of the telescope based data. The fourteen objects studied in the laboratory are fragments or materials acquired through ground-tests of scaled-model satellites/rocket bodies as well as material samples in more/less "flight-ready" condition. All fragments were measured at 10 increments in a full 360 rotation at 6 , 36 , and 60 phase angles. This paper will investigate published color photometric data for a series of orbital debris targets and compare it to the empirical photometric measurements generated in the OMC. Using the data acquired over specific rotational angles through different filters (B, V, R, I), a color index is acquired (B-R, R-I). Using these values and their associated lightcurves, this laboratory data is compared to observational data obtained on the 1 m telescope of the Astronomical Institute of the University of Bern (AUIB), the 0.9 m operated by the Small- and Medium-Aperture Research Telescope System (SMARTS) Consortium and the Curtis-Schmidt 0.6 m Michigan Orbital Debris Space Debris Telescope both located at Cerro Tololo Inter-American Observatory (CTIO). An empirical based optical characterization model will be presented to provide preliminary correlations between laboratory based and telescope-based data in the context of classification of GEO debris objects.

  11. Spinal cord magnetic resonance imaging in suspected multiple sclerosis

    International Nuclear Information System (INIS)

    Lycklama a Nijeholt, G.J.; Bergers, E.; Castelijns, J.A.; Barkhof, F.; Uitdehaag, B.M.J.; Polman, C.H.

    2000-01-01

    We examined the value of spinal cord magnetic resonance imaging (MRI) in the diagnostic work-up of multiple sclerosis (MS). Forty patients suspected of having MS were examined within 24 months after the start of symptoms. Disability was assessed, and symptoms were categorized as either brain or spinal cord. Work-up further included cerebrospinal fluid analysis and standard proton-density, T2-, and T1-weighted gadolinium-enhanced brain and spinal cord MRI. Patients were categorized as either clinically definite MS (n = 13), laboratory-supported definite MS (n = 14), or clinically probable MS (n = 4); four patients had clinically probable MS, and in nine MS was suspected. Spinal cord abnormalities were found in 35 of 40 patients (87.5 %), consisting of focal lesions in 31, only diffuse abnormalities in two, and both in two. Asymptomatic spinal cord lesions occurred in six patients. All patients with diffuse spinal cord abnormality had clear spinal cord symptoms and a primary progressive disease course. In clinically definite MS, the inclusion of spinal imaging increased the sensitivity of MRI to 100 %. Seven patients without a definite diagnosis had clinically isolated syndromes involving the spinal cord. Brain MRI was inconclusive, while all had focal spinal cord lesions which explained symptoms and ruled out other causes. Two other patients had atypical brain abnormalities suggesting ischemic/vascular disease. No spinal cord abnormalities were found, and during follow-up MS was ruled out. Spinal cord abnormalities are common in suspected MS, and may occur asymptomatic. Although diagnostic classification is seldom changed, spinal cord imaging increases diagnostic sensitivity of MRI in patients with suspected MS. In addition, patients with primary progressive MS may possibly be earlier diagnosed. Finally, differentiation with atypical lesions may be improved. (orig.)

  12. MRI for clinically suspected pediatric appendicitis: an implemented program

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Michael M.; Gustas, Cristy N.; Choudhary, Arabinda K.; Methratta, Sosamma T.; Hulse, Michael A.; Eggli, Kathleen D.; Boal, Danielle K.B. [Penn State Milton S. Hershey Medical Center, Department of Radiology, Mail Code H066, 500 University Drive, P.O. Box 850, Hershey, PA (United States); Geeting, Glenn [Penn State Milton S. Hershey Medical Center, Department of Emergency Medicine, Hershey, PA (United States)

    2012-09-15

    Emergent MRI is now a viable alternative to CT for evaluating appendicitis while avoiding the detrimental effects of ionizing radiation. However, primary employment of MRI in the setting of clinically suspected pediatric appendicitis has remained significantly underutilized. To describe our institution's development and the results of a fully implemented clinical program using MRI as the primary imaging evaluation for children with suspected appendicitis. A four-sequence MRI protocol consisting of coronal and axial single-shot turbo spin-echo (SS-TSE) T2, coronal spectral adiabatic inversion recovery (SPAIR), and axial SS-TSE T2 with fat saturation was performed on 208 children, ages 3 to 17 years, with clinically suspected appendicitis. No intravenous or oral contrast material was administered. No sedation was administered. Data collection includes two separate areas: time parameter analysis and MRI diagnostic results. Diagnostic accuracy of MRI for pediatric appendicitis indicated a sensitivity of 97.6% (CI: 87.1-99.9%), specificity 97.0% (CI: 93.2-99.0%), positive predictive value 88.9% (CI: 76.0-96.3%), and negative predictive value 99.4% (CI: 96.6-99.9%). Time parameter analysis indicated clinical feasibility, with time requested to first sequence obtained mean of 78.7 +/- 52.5 min, median 65 min; first-to-last sequence time stamp mean 14.2 +/- 8.8 min, median 12 min; last sequence to report mean 57.4 +/- 35.2 min, median 46 min. Mean age was 11.2 +/- 3.6 years old. Girls represented 57% of patients. MRI is an effective and efficient method of imaging children with clinically suspected appendicitis. Using an expedited four-sequence protocol, sensitivity and specificity are comparable to CT while avoiding the detrimental effects of ionizing radiation. (orig.)

  13. Periodicity and repeatability in data

    Science.gov (United States)

    Southwood, D.

    Using magnetic data from the first two years in Saturn orbit, the basic periodicity of apparent is examined with the aim of elucidating the `cam' shaft model of Espinosa et al. (2003) identifying the nature of the `cam' and giving a definitive period for its rotation. An initial hypothesis, supported by the spectral analysis of analysis of the first 8 months in orbit Gianpieri et al. (2006), is made that the source of the period is linked to something inside the planet and therefore that the source inertia means that the period effectively does not change over the 2 years. Moreover one expects that the source phase is fixed. Using this approach, not only can the period identified by spectral analysis (647.1 + 0.6 min.) be verified but also by phase analysis between successive passes over the 2 years the period can be refined to 647.6 + 0.1 min. The signal itself is remarkably reproducible from pass to pass. It appears in all three components of the field and its polarisation is unambiguously not attributable to direct detection of an internal field. Not only does the signal not decay rapidly with distance from the planet, but although it has the m=1 symmetry of a tilted dipole, the field lines diverge from the planet indicating an exterior source. This feature led to the `cam' model. The polarisation and comparisons of passes with different latitude profiles show a surprising north-south symmetry in the azimuthal field. The absence of asymmetry with respect to the magnetic equator rules out a direct magnetospheric-ionospheric interaction source. Accordingly, it is proposed that the basic `cam' effect is generated by a single hemisphere anomaly which creates hemisphere to hemisphere field aligned currents. The existence of Saturn phase related anomaly appears to produce a basic asymmetry in the inner magnetosphere that sets the phase of both an inflowing and outflowing sector in a rotating circulation system.

  14. A planet in a polar orbit of 1.4 solar-mass star

    Directory of Open Access Journals (Sweden)

    Guenther E.W.

    2015-01-01

    Full Text Available Although more than a thousand transiting extrasolar planets have been discovered, only very few of them orbit stars that are more massive than the Sun. The discovery of such planets is interesting, because they have formed in disks that are more massive but had a shorter life time than those of solar-like stars. Studies of planets more massive than the Sun thus tell us how the properties of the proto-planetary disks effect the formation of planets. Another aspect that makes these planets interesting is that they have kept their original orbital inclinations. By studying them we can thus find out whether the orbital axes planets are initially aligned to the stars rotational axes, or not. Here we report on the discovery of a planet of a 1.4 solar-mass star with a period of 5.6 days in a polar orbit made by CoRoT. This new planet thus is one of the few known close-in planets orbiting a star that is substantially more massive than the Sun.

  15. Optimisation of the digital radiographic imaging of suspected non-accidental injury

    Science.gov (United States)

    Offiah, Amaka

    Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI). Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI. Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor. Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection

  16. Comparison of precision orbit derived density estimates for CHAMP and GRACE satellites

    Science.gov (United States)

    Fattig, Eric Dale

    nine combinations of density and ballistic coefficient correlated half-lives. These half-lives are varied among values of 1.8, 18, and 180 minutes. A total of forty-five sets of results emerge from the orbit determination process for all combinations of baseline density model and half-lives. Each time period is examined for both CHAMP and GRACE-A, and the results are analyzed. Results are averaged from all solutions periods for 2004--2007. In addition, results are averaged after binning according to solar and geomagnetic activity levels. For any given day in this period, a ballistic coefficient correlated half-life of 1.8 minutes yields the best correlation and root mean square values for both CHAMP and GRACE. For CHAMP, a density correlated half-life of 18 minutes is best for higher levels of solar and geomagnetic activity, while for lower levels 180 minutes is usually superior. For GRACE, 180 minutes is nearly always best. The three Jacchia-based atmospheric models yield very similar results. The CIRA 1972 or Jacchia 1971 models as baseline consistently produce the best results for both satellites, though results obtained for Jacchia-Roberts are very similar to the other Jacchia-based models. Data are examined in a similar manner for the extended solar minimum period during 2008 and 2009, albeit with a much smaller sampling of data. With the exception of some atypical results, similar combinations of half-lives and baseline atmospheric model produce the best results. A greater sampling of data will aid in characterizing density in a period of especially low solar activity. In general, cross correlation values for CHAMP and GRACE revealed that the POE method matched trends observed by the accelerometers very well. However, one period of time deviated from this trend for the GRACE-A satellite. Between late October 2005 and January 2006, correlations for GRACE-A were very low. Special examination of the surrounding months revealed the extent of time this period covered

  17. Herbal hepatotoxicity: suspected cases assessed for alternative causes.

    Science.gov (United States)

    Teschke, Rolf; Schulze, Johannes; Schwarzenboeck, Alexander; Eickhoff, Axel; Frenzel, Christian

    2013-09-01

    Alternative explanations are common in suspected drug-induced liver injury (DILI) and account for up to 47.1% of analyzed cases. This raised the question of whether a similar frequency may prevail in cases of assumed herb-induced liver injury (HILI). We searched the Medline database for the following terms: herbs, herbal drugs, herbal dietary supplements, hepatotoxic herbs, herbal hepatotoxicity, and herb-induced liver injury. Additional terms specifically addressed single herbs and herbal products: black cohosh, Greater Celandine, green tea, Herbalife products, Hydroxycut, kava, and Pelargonium sidoides. We retrieved 23 published case series and regulatory assessments related to hepatotoxicity by herbs and herbal dietary supplements with alternative causes. The 23 publications comprised 573 cases of initially suspected HILI; alternative causes were evident in 278/573 cases (48.5%). Among them were hepatitis by various viruses (9.7%), autoimmune diseases (10.4%), nonalcoholic and alcoholic liver diseases (5.4%), liver injury by comedication (DILI and other HILI) (43.9%), and liver involvement in infectious diseases (4.7%). Biliary and pancreatic diseases were frequent alternative diagnoses (11.5%), raising therapeutic problems if specific treatment is withheld; pre-existing liver diseases including cirrhosis (9.7%) were additional confounding variables. Other diagnoses were rare, but possibly relevant for the individual patient. In 573 cases of initially assumed HILI, 48.5% showed alternative causes unrelated to the initially incriminated herb, herbal drug, or herbal dietary supplement, calling for thorough clinical evaluations and appropriate causality assessments in future cases of suspected HILI.

  18. Percutaneous transhepatic vs. endoscopic retrograde biliary drainage for suspected malignant hilar obstruction: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Al-Kawas, Firas; Aslanian, Harry; Baillie, John; Banovac, Filip; Buscaglia, Jonathan M; Buxbaum, James; Chak, Amitabh; Chong, Bradford; Coté, Gregory A; Draganov, Peter V; Dua, Kulwinder; Durkalski, Valerie; Elmunzer, B Joseph; Foster, Lydia D; Gardner, Timothy B; Geller, Brian S; Jamidar, Priya; Jamil, Laith H; Keswani, Rajesh N; Khashab, Mouen A; Lang, Gabriel D; Law, Ryan; Lichtenstein, David; Lo, Simon K; McCarthy, Sean; Melo, Silvio; Mullady, Daniel; Nieto, Jose; Bayne Selby, J; Singh, Vikesh K; Spitzer, Rebecca L; Strife, Brian; Tarnaksy, Paul; Taylor, Jason R; Tokar, Jeffrey; Wang, Andrew Y; Williams, April; Willingham, Field; Yachimski, Patrick

    2018-02-14

    The optimal approach to the drainage of malignant obstruction at the liver hilum remains uncertain. We aim to compare percutaneous transhepatic biliary drainage (PTBD) to endoscopic retrograde cholangiography (ERC) as the first intervention in patients with cholestasis due to suspected malignant hilar obstruction (MHO). The INTERCPT trial is a multi-center, comparative effectiveness, randomized, superiority trial of PTBD vs. ERC for decompression of suspected MHO. One hundred and eighty-four eligible patients across medical centers in the United States, who provide informed consent, will be randomly assigned in 1:1 fashion via a web-based electronic randomization system to either ERC or PTBD as the initial drainage and, if indicated, diagnostic procedure. All subsequent clinical interventions, including crossover to the alternative procedure, will be dictated by treating physicians per usual clinical care. Enrolled subjects will be assessed for successful biliary drainage (primary outcome measure), adequate tissue diagnosis, adverse events, the need for additional procedures, hospitalizations, and oncological outcomes over a 6-month follow-up period. Subjects, treating clinicians and outcome assessors will not be blinded. The INTERCPT trial is designed to determine whether PTBD or ERC is the better initial approach when managing a patient with suspected MHO, a common clinical dilemma that has never been investigated in a randomized trial. ClinicalTrials.gov, Identifier: NCT03172832 . Registered on 1 June 2017.

  19. Peripheral orbit model

    CERN Document Server

    Hara, Yasuo

    1975-01-01

    Peripheral orbit model, in which an incoming hadron is assumed to revolve in a peripheral orbit around a target hadron, is discussed. The non-diffractive parts of two-body reaction amplitudes of hadrons are expressed in terms of the radius, width an absorptivity of the orbit. The radius of the orbit is about 1 fm and the width of the orbit is determined by the range of the interaction between the hadrons. The model reproduces all available experimental data on differential cross-sections and polarizations of $K^{-}p\\to K^{-}p$ and $\\bar K^{\\circ}n$ reactions for all angles successfully. This contribution is not included in the proceedings since it will appear in Progress of Theoretical Physics Vol. 51 (1974) No 2. Any person interested in the subject may apply for reprints to the author.

  20. Drift-free solar sail formations in elliptical Sun-synchronous orbits

    Science.gov (United States)

    Parsay, Khashayar; Schaub, Hanspeter

    2017-10-01

    To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this study is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail. These averaged rates are used to analytically derive the first-order necessary conditions for a drift-free solar sail formation in Sun-synchronous orbits, assuming a fixed Sun-pointing orientation for each sail in formation. The validity of the first-order necessary conditions are illustrated by designing quasi-periodic relative motions. Next, nonlinear programming is applied to design truly drift-free two-craft solar sail formations. Lastly, analytic expressions are derived to determine the long-term dynamics and sensitivity of the formation with respect to constant attitude errors, uncertainty in orbital elements, and uncertainty in a sail's characteristic acceleration.

  1. 9 CFR 381.78 - Condemnation of carcasses and parts: separation of poultry suspected of containing biological...

    Science.gov (United States)

    2010-01-01

    ...: separation of poultry suspected of containing biological residues. 381.78 Section 381.78 Animals and Animal... carcasses and parts: separation of poultry suspected of containing biological residues. (a) At the time of... to be not adulterated. (b) When a lot of poultry suspected of containing biological residues is...

  2. Orbital transport

    International Nuclear Information System (INIS)

    Oertel, H. Jr.; Koerner, H.

    1993-01-01

    The Third Aerospace Symposium in Braunschweig presented, for the first time, the possibility of bringing together the classical disciplines of aerospace engineering and the natural science disciplines of meteorology and air chemistry in a european setting. In this way, aspects of environmental impact on the atmosphere could be examined quantitatively. An essential finding of the european conference, is the unrestricted agreement of the experts that the given launch frequencies of the present orbital transport result in a negligible amount of pollutants being released in the atmosphere. The symposium does, however, call attention to the increasing need to consider the effect of orbital and atmospheric environmental impact of a future increase in launch frequencies of orbital transport in connection with future space stations. The Third Aerospace Symposium, 'Orbital Transport, Technical, Meteorological and Chemical Aspects', constituted a first forum of discussion for engineers and scientists. Questions of new orbital transport technologies and their environmental impact were to be discussed towards a first consensus. Through the 34 reports and articles, the general problems of space transportation and environmental protection were addressed, as well as particular aspects of high temperatures during reentry in the atmosphere of the earth, precision navigation of flight vehicles or flow behavior and air chemistry in the stratosphere. (orig./CT). 342 figs

  3. Orbital apex syndrome associated with fractures of the inferomedial orbital wall

    Directory of Open Access Journals (Sweden)

    Sugamata A

    2013-03-01

    Full Text Available Akira SugamataDepartment of Plastic and Reconstructive Surgery, Tokyo Medical University Hachioji Medical Center, Tokyo, JapanAbstract: Although trauma is one of the main causes of orbital apex syndrome (OAS, reports of OAS associated with orbital fractures are relatively rare. We recently treated two patients who sustained severe visual impairment with damage to multiple cranial nerves (third to sixth associated with inferomedial orbital wall fractures. In these patients, posterior movement of the globe caused neuropathy of the cranial and optic nerves by posterior globe edema and hemorrhage, or direct impact between the globe and wall, which might then have induced OAS in the cases described in this report. Steroid therapy was unsuccessful for optic neuropathy due to the delay between injury and administration. When treating patients with inferomedial orbital blowout fractures due to globe-to-wall contact, it is necessary to routinely assess and monitor visual acuity since there may be a delay between the injury and OAS onset.Keywords: orbital apex syndrome, orbital fracture, blowout fracture, optic nerve, globe-to-wall contact mechanism

  4. Charge-Orbital Ordering and Verwey Transition in Magnetite Measured by Resonant Soft X-Ray Scattering

    International Nuclear Information System (INIS)

    Huang, D.J.; Lin, H.-J.; Okamoto, J.; Hsu, C.-H.; Huang, C.-M.; Yang, C.S.; Chao, K.S.; Wu, W.B.; Jeng, H.-T.; Guo, G.Y.; Ling, D.C.; Chen, C.T.

    2006-01-01

    We report experimental evidence for the charge-orbital ordering in magnetite below the Verwey transition temperature T V . Measurements of O K-edge resonant x-ray scattering on magnetite reveal that the O 2p states in the vicinity of the Fermi level exhibit a charge-orbital ordering along the c axis with a spatial periodicity of the doubled lattice parameter of the undistorted cubic phase. Such a charge-orbital ordering vanishes abruptly above T V and exhibits a thermal hysteresis, correlating closely with the Verwey transition in magnetite

  5. Suspected adverse reactions to veterinary drugs reported in South Africa (January 1998 - February 2001 : special report

    Directory of Open Access Journals (Sweden)

    R. Gehring

    2001-07-01

    Full Text Available The Veterinary Pharmacovigilance Centre received 59 reports of suspected adverse drug reactions during the period January 1998 - February 2001. The number of reports received increased after the establishment of a formal procedure for recording and responding to reports. The number of reports received per species was: dogs 19, cats 15, cattle 7, sheep/ goats 6, chickens 4, pigs 3, horses 2 and giraffe 1. Many different types of adverse reactions were reported, including lack of efficacy, hypersensitivity, inappropriate use of products by non-veterinarians, known adverse effects and adverse effects encountered with extra-label use of products.

  6. Prevalence of Earth-size planets orbiting Sun-like stars.

    Science.gov (United States)

    Petigura, Erik A; Howard, Andrew W; Marcy, Geoffrey W

    2013-11-26

    Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration's Kepler mission. We found 603 planets, including 10 that are Earth size ( ) and receive comparable levels of stellar energy to that of Earth (1 - 2 R[Symbol: see text] ). We account for Kepler's imperfect detectability of such planets by injecting synthetic planet-caused dimmings into the Kepler brightness measurements and recording the fraction detected. We find that 11 ± 4% of Sun-like stars harbor an Earth-size planet receiving between one and four times the stellar intensity as Earth. We also find that the occurrence of Earth-size planets is constant with increasing orbital period (P), within equal intervals of logP up to ~200 d. Extrapolating, one finds 5.7(-2.2)(+1.7)% of Sun-like stars harbor an Earth-size planet with orbital periods of 200-400 d.

  7. AN IMPROVED DISTANCE AND MASS ESTIMATE FOR SGR A* FROM A MULTISTAR ORBIT ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Boehle, A.; Ghez, A. M.; Meyer, L.; Yelda, S.; Albers, S.; Martinez, G. D.; Becklin, E. E.; Do, T.; Morris, M. R.; Sitarski, B.; Witzel, G. [UCLA, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Schödel, R. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía S/N, E-18008 Granada (Spain); Lu, J. R. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Matthews, K., E-mail: aboehle@astro.ucla.edu [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, MC 301-17, Pasadena, CA 91125 (United States)

    2016-10-10

    We present new, more precise measurements of the mass and distance of our Galaxy’s central supermassive black hole, Sgr A*. These results stem from a new analysis that more than doubles the time baseline for astrometry of faint stars orbiting Sgr A*, combining 2 decades of speckle imaging and adaptive optics data. Specifically, we improve our analysis of the speckle images by using information about a star’s orbit from the deep adaptive optics data (2005–2013) to inform the search for the star in the speckle years (1995–2005). When this new analysis technique is combined with the first complete re-reduction of Keck Galactic Center speckle images using speckle holography, we are able to track the short-period star S0-38 ( K -band magnitude = 17, orbital period = 19 yr) through the speckle years. We use the kinematic measurements from speckle holography and adaptive optics to estimate the orbits of S0-38 and S0-2 and thereby improve our constraints of the mass ( M {sub bh}) and distance ( R {sub o} ) of Sgr A*: M {sub bh} = (4.02 ± 0.16 ± 0.04) × 10{sup 6} M {sub ⊙} and 7.86 ± 0.14 ± 0.04 kpc. The uncertainties in M {sub bh} and R {sub o} as determined by the combined orbital fit of S0-2 and S0-38 are improved by a factor of 2 and 2.5, respectively, compared to an orbital fit of S0-2 alone and a factor of ∼2.5 compared to previous results from stellar orbits. This analysis also limits the extended dark mass within 0.01 pc to less than 0.13 × 10{sup 6} M {sub ⊙} at 99.7% confidence, a factor of 3 lower compared to prior work.

  8. Incidence of clinically suspected venous thromboembolism in British Indian patients.

    Science.gov (United States)

    Siddiqui, B M; Patel, M S; Rudge, S; Best, A; Mangwani, J

    2018-05-01

    Introduction Venous thromboembolism (VTE) remains a major public health issue around the world. Ethnicity is known to alter the incidence of VTE. To our knowledge, there are no reports in the literature investigating the incidence of VTE in British Indians. The aim of this study was to investigate the rates of symptomatic VTE in British Indian patients in the UK. Methods Patients referred to our institution between January 2011 and August 2013 with clinically suspected VTE were eligible for inclusion in the study. Those not of British Indian or Caucasian ethnicity were excluded. A retrospective review of these two cohorts was conducted. Results Overall, 15,529 cases were referred to our institution for suspected VTE. This included 1,498 individuals of British Indian ethnicity. Of these, 182 (12%) had confirmed VTE episodes. A further 13,159 of the patients with suspected VTE were coded as Caucasian, including 2,412 (16%) who had confirmed VTE events. VTE rates were a third lower in British Indians with clinically suspected VTE than in the equivalent Caucasian group. The British Indian cohort presented with VTE at a much earlier age than Caucasians (mean 57.0 vs 68.0 years). Conclusions This study suggests that British Indian patients have a lower incidence of VTE and are more likely to present at an earlier age than Caucasians. There was no significant difference in VTE type (deep vein thrombosis vs pulmonary embolism) among the ethnic groups. Clinicians should be aware of variations within ethnicities but should continue to adhere to existing VTE prevention guidance.

  9. Orbit error characteristic and distribution of TLE using CHAMP orbit data

    Science.gov (United States)

    Xu, Xiao-li; Xiong, Yong-qing

    2018-02-01

    Space object orbital covariance data is required for collision risk assessments, but publicly accessible two line element (TLE) data does not provide orbital error information. This paper compared historical TLE data and GPS precision ephemerides of CHAMP to assess TLE orbit accuracy from 2002 to 2008, inclusive. TLE error spatial variations with longitude and latitude were calculated to analyze error characteristics and distribution. The results indicate that TLE orbit data are systematically biased from the limited SGP4 model. The biases can reach the level of kilometers, and the sign and magnitude are correlate significantly with longitude.

  10. Vascular factors in suspected normal pressure hydrocephalus

    Science.gov (United States)

    Agerskov, Simon; Rabiei, Katrin; Marlow, Thomas; Jensen, Christer; Guo, Xinxin; Kern, Silke; Wikkelsø, Carsten; Skoog, Ingmar

    2016-01-01

    Objective: We examined clinical and imaging findings of suspected idiopathic normal pressure hydrocephalus (iNPH) in relation to vascular risk factors and white matter lesions (WMLs), using a nested case-control design in a representative, population-based sample. Methods: From a population-based sample, 1,235 persons aged 70 years or older were examined with CT of the brain between 1986 and 2000. We identified 55 persons with hydrocephalic ventricular enlargement, i.e., radiologic findings consistent with iNPH. Among these, 26 had clinical signs that fulfilled international guideline criteria for probable iNPH. These cases were labeled suspected iNPH. Each case was matched to 5 controls from the same sample, based on age, sex, and study cohort. Data on risk factors were obtained from clinical examinations and the Swedish Hospital Discharge Register. History of hypertension, diabetes mellitus (DM), smoking, overweight, history of coronary artery disease, stroke/TIA, and WMLs on CT were examined. Risk factors associated with iNPH with a p value <0.1 in χ2 tests were included in conditional logistic regression models. Results: In the regression analyses, suspected iNPH was related to moderate to severe WMLs (odds ratio [OR] 5.2; 95% confidence interval [CI]: 1.5–17.6), while hydrocephalic ventricular enlargement was related to hypertension (OR 2.7; 95% CI: 1.1–6.8), moderate to severe WMLs (OR 6.5; 95% CI: 2.1–20.3), and DM (OR 4.3; 95% CI: 1.1–16.3). Conclusions: Hypertension, WMLs, and DM were related to clinical and imaging features of iNPH, suggesting that vascular mechanisms are involved in the pathophysiology. These findings might have implications for understanding disease mechanisms in iNPH and possibly prevention. PMID:26773072

  11. CT for suspected appendicitis in children: an analysis of diagnostic errors

    International Nuclear Information System (INIS)

    Taylor, George A.; Callahan, Michael J.; Rodriguez, Diana; Smink, Douglas S.

    2006-01-01

    Mistakes have been made by the use of CT in diagnosing children with suspected appendicitis. Although others have reported the frequency of diagnostic errors, we were unable to find any studies that addressed the specific situations in which diagnostic errors occurred in children with suspected appendicitis. To investigate the frequency and type of diagnostic errors resulting from CT of children with suspected appendicitis when compared to surgical and pathological diagnosis. We reviewed imaging, clinical and pathological data on 1,207 consecutive pediatric patients who underwent CT examination for suspected appendicitis. Imaging findings were categorized as false-positive, false-negative, or indeterminate. Errors were classified as interpretative, technical or unavoidable. Concordance between surgical and pathological findings was also evaluated. The imaging findings of 34 patients (2.8%) were discrepant with the pathological examination or clinical follow-up. The errors in 23 cases were classified as interpretive (68%) and 11 as unavoidable (32%), and no errors were classified as technical. There were 23 false-positive errors (68%), 6 false-negative errors (18%), and 5 indeterminate imaging studies (15%). Isolated CT findings of an enlarged (greater than 6 mm) appendix, fat stranding, thickened bowel or non-visualization of the distal appendix were the most common false-positive CT findings. Of these 34 patients, 22 underwent appendectomy, with 10 (45%) having discordant surgical and pathological findings. (orig.)

  12. GLONASS Orbits in Teqc: Methodology and Future Extension for Using SP3 Orbits

    Science.gov (United States)

    Estey, L.; Wier, S.

    2011-12-01

    UNAVCO's teqc software package provides translation of a wide variety of GNSS receiver formats, metadata editing (either during translation to RINEX or on existing RINEX files), time-windowing and epoch decimation editing, and quality check (qc) analysis. Teqc is used extensively in GNSS pre-processing, and is designed to handle mixed satellite constellations, such as GPS, GLONASS, Galileo, and SBAS. The latest release of teqc adds GLONASS orbit calculations using GLONASS broadcast navigation messages, read from RINEX file format, during qc. The ephemerides for each GLONASS SV have time and orbit position in Earth-centered, Earth-fixed x, y, and z coordinates. Following Schenewerk [2003], we use trigonometric interpolation, essentially a fit of a partial sum of the Fourier series for each time-varying cartesian orbital component, allowing estimates of orbit positions at most GLONASS observation times. Tests show the interpolated GLONASS orbits made from the broadcast messages diverge from final orbits little more than the same differences using GPS orbits computed from their broadcast messages. Since GLONASS ephemerides do not use Keplerian orbital elements, GLONASS SV orbits can only be interpolated using this method for time intervals when an adequate sequence of ephemerides are available. For typical daily navigation messages collected at a single sit, when a GLONASS SV is in view less than three hours, that SV's signals are generally not used by teqc due to less precise orbit positions. Teqc quality control including SV position can now use GPS alone, GLONASS alone, or the joint solution. Future work will extend teqc to use SP3 format files, such as the IGS final orbit files, and SBAS data, which have broadcast ephemerides with elements similar to GLONASS.

  13. Optimizing imaging in suspected appendicitis (OPTIMAP-study: A multicenter diagnostic accuracy study of MRI in patients with suspected acute appendicitis. Study Protocol

    Directory of Open Access Journals (Sweden)

    Bossuyt Patrick MM

    2010-10-01

    Full Text Available Abstract Background In patients with clinically suspected appendicitis, imaging is needed to substantiate the clinical diagnosis. Imaging accuracy of ultrasonography (US is suboptimal, while the most accurate technique (CT is associated with cancer related deaths through exposure to ionizing radiation. MRI is a potential replacement, without associated ionizing radiation and no need for contrast medium administration. If MRI is proven to be sufficiently accurate, it could be introduced in the diagnostic pathway of patients with suspected appendicitis, increasing diagnostic accuracy and improving clinical outcomes, without the risk of radiation induced cancer or iodinated contrast medium-related drawbacks. The multicenter OPTIMAP study was designed to estimate the diagnostic accuracy of MRI in patients with suspected acute appendicitis in the general population. Methods/Design Eligible for this study are consecutive patients presenting with clinically suspected appendicitis at the emergency department in six centers. All patients will undergo imaging according to the Dutch guideline for acute appendicitis: initial ultrasonography in all and subsequent CT whenever US does not confirm acute appendicitis. Then MRI is performed in all patients, but the results are not used for patient management. A final diagnosis assigned by an expert panel, based on all available information including 3-months follow-up, except MRI findings, is used as the reference standard in estimating accuracy. We will calculate the sensitivity, specificity, predictive values and inter-observer agreement of MRI, and aim to include 230 patients. Patient acceptance and total imaging costs will also be evaluated. Discussion If MRI is found to be sufficiently accurate, it could replace CT in some or all patients. This will limit or obviate the ionizing radiation exposure associated risk of cancer induction and contrast medium induced nephropathy with CT, preventing the burden and

  14. CT and MRI evaluation of orbital tumors: our experience

    International Nuclear Information System (INIS)

    Cabrini, Marcelo; Docampo, Jorge; Martinez, Manuel; Bruno, Claudio; Morales, Carlos

    2007-01-01

    Purpose: To show our experience in the evaluation of orbital masses on computed tomography (CT) and magnetic resonance imaging (MRI). To describe their most important findings and epidemiological features found on literature review, related to their differential diagnosis. Materials and methods: During a 48-months period of time, 26 patients (13 male, 13 female; age range, 3 to 75 years) with orbital tumors were evaluated. Seventeen patients underwent MR scans, 8 underwent CT scans, and one underwent both imaging methods. It was employed 0,5 and 1 Tesla MR scanners, and axial-helical CT scanners. Results: Benign lesions were found on 7 patients (cavernous hemangioma [n=2], meningioma [n=1], epidermoid cyst [n=1], dermoid cyst [n=1], lipoma [n=1], orbital vein deformity [n=1]). It was found lesions with undetermined behavior (optical nerve glioma [n=2]), and malignant ones were found on 17 patients (metastatic lesions [n=5], non- Hodgkin's lymphoma [n=3], hemangiopericytoma [n=2], retinoblastoma [n=2], rhabdomyosarcoma [n=2], melanoma [n=1], and lacrimal adenocarcinoma [n=1]). Conclusion: In our experience, 65.4% was malignant tumors (orbital metastasis was the most common; 19.2%). More than one-quarter was benign tumor, where cavernous hemangioma was the most frequent. (author) [es

  15. Nontraumatic orbital roof encephalocele.

    Science.gov (United States)

    Hoang, Amber; Maugans, Todd; Ngo, Thang; Ikeda, Jamie

    2017-02-01

    Intraorbital meningoencephaloceles occur most commonly as a complication of traumatic orbital roof fractures. Nontraumatic congenital orbital meningoncephaloceles are very rare, with most secondary to destructive processes affecting the orbit and primary skull defects. Treatment for intraorbital meningoencephaloceles is surgical repair, involving the excision of herniated brain parenchyma and meninges and reconstruction of the osseous defect. Most congenital lesions present in infancy with obvious globe and orbital deformities; we report an orbital meningoencephalocele in a 3-year-old girl who presented with ptosis. Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  16. Characterization of waste streams and suspect waste from largest Los Alamos National Laboratory generators

    International Nuclear Information System (INIS)

    Soukup, J.D.; Erpenbeck, G.J.

    1995-01-01

    A detailed waste stream characterization of 4 primary generators of low level waste at LANL was performed to aid in waste minimization efforts. Data was compiled for these four generators from 1988 to the present for analyses. Prior waste minimization efforts have focused on identifying waste stream processes and performing source materials substitutions or reductions where applicable. In this historical survey, the generators surveyed included an accelerator facility, the plutonium facility, a chemistry and metallurgy research facility, and a radiochemistry research facility. Of particular interest in waste minimization efforts was the composition of suspect low level waste in which no radioactivity is detected through initial survey. Ultimately, this waste is disposed of in the LANL low level permitted waste disposal pits (thus filling a scarce and expensive resource with sanitary waste). Detailed analyses of the waste streams from these 4 facilities, have revealed that suspect low level waste comprises approximately 50% of the low level waste by volume and 47% by weight. However, there are significant differences in suspect waste density when one considers the radioactive contamination. For the 2 facilities that deal primarily with beta emitting activation and spallation products (the radiochemistry and accelerator facilities), the suspect waste is much lower density than all low level waste coming from those facilities. For the 2 facilities that perform research on transuranics (the chemistry and metallurgy research and plutonium facilities), suspect waste is higher in density than all the low level waste from those facilities. It is theorized that the low density suspect waste is composed primarily of compactable lab trash, most of which is not contaminated but can be easily surveyed. The high density waste is theorized to be contaminated with alpha emitting radionuclides, and in this case, the suspect waste demonstrates fundamental limits in detection

  17. Testing General Relativity with Stellar Orbits around the Supermassive Black Hole in Our Galactic Center.

    Science.gov (United States)

    Hees, A; Do, T; Ghez, A M; Martinez, G D; Naoz, S; Becklin, E E; Boehle, A; Chappell, S; Chu, D; Dehghanfar, A; Kosmo, K; Lu, J R; Matthews, K; Morris, M R; Sakai, S; Schödel, R; Witzel, G

    2017-05-26

    We demonstrate that short-period stars orbiting around the supermassive black hole in our Galactic center can successfully be used to probe the gravitational theory in a strong regime. We use 19 years of observations of the two best measured short-period stars orbiting our Galactic center to constrain a hypothetical fifth force that arises in various scenarios motivated by the development of a unification theory or in some models of dark matter and dark energy. No deviation from general relativity is reported and the fifth force strength is restricted to an upper 95% confidence limit of |α|<0.016 at a length scale of λ=150 astronomical units. We also derive a 95% confidence upper limit on a linear drift of the argument of periastron of the short-period star S0-2 of |ω[over ˙]_{S0-2}|<1.6×10^{-3}  rad/yr, which can be used to constrain various gravitational and astrophysical theories. This analysis provides the first fully self-consistent test of the gravitational theory using orbital dynamic in a strong gravitational regime, that of a supermassive black hole. A sensitivity analysis for future measurements is also presented.

  18. [Pre-trial psychiatric reports on Antillean suspected offenders in the Netherlands and on the Dutch Antilles].

    Science.gov (United States)

    Vinkers, D J; Heytel, F G M; Matroos, G M; Hermans, K M; Hoek, H W

    2010-01-01

    The registered criminality among Antilleans living in the Netherlands is much higher than among Antilleans living on the Dutch Antilles (113 offences and 11 offences respectively, per year per 1000 persons, pDutch Antilles (n=199) between 2000 and 2006. A careful study was made of pre-trial psychiatric reports on Antillean suspected offenders (referred to as suspects) in the Netherlands and of comparable reports on Antillean suspects on the Dutch Antilles. There was no significant difference in the prevalence of mental disorders among Antillean suspects in the Netherlands (22.3%) and on the Dutch Antilles (20.3%). Abuse of drugs and cannabis was more prevalent on the Dutch Antilles where treatment for addiction is less frequently available than in the Netherlands. Mental retardation was ascertained more often among Antilleans in the Netherlands (22.4%) than among Antilleans on the Dutch Antilles (15.1%). Antillean suspects on the Dutch Antilles were more often found to be fully responsible for their actions than were Antillean suspects in the Netherlands (65.3% versus 19.1%, pDutch Antilles.

  19. Outcomes in Elderly Patients With Severely Calcified Coronary Lesions Undergoing Orbital Atherectomy.

    Science.gov (United States)

    Lee, Michael S; Shlofmitz, Evan; Lluri, Gentian; Shlofmitz, Richard A

    2017-04-01

    We evaluated the clinical outcomes of elderly patients who underwent orbital atherectomy for the treatment of severe coronary artery calcification (CAC) prior to stenting. Percutaneous coronary intervention (PCI) of severe CAC is associated with worse clinical outcomes including death, myocardial infarction (MI), and target vessel revascularization (TVR). The elderly represents a high-risk group of patients, often have more comorbid conditions, and have worse outcomes after PCI compared to younger patients. Clinical trials and a large multicenter registry have demonstrated the safety and efficacy of orbital atherectomy for the treatment of severe CAC. Clinical outcomes of elderly patients who undergo orbital atherectomy are unknown. Of the 458 patients, 229 were ≥75 years old (elderly) and 229 were atherectomy. It is a safe and effective treatment strategy for elderly patients with severe CAC as the clinical outcomes were similar to their younger counterparts. A randomized trial should further clarify the role of orbital atherectomy in these patients. © 2017, Wiley Periodicals, Inc.

  20. E-Orbit Functions

    Directory of Open Access Journals (Sweden)

    Jiri Patera

    2008-01-01

    Full Text Available We review and further develop the theory of $E$-orbit functions. They are functions on the Euclidean space $E_n$ obtained from the multivariate exponential function by symmetrization by means of an even part $W_{e}$ of a Weyl group $W$, corresponding to a Coxeter-Dynkin diagram. Properties of such functions are described. They are closely related to symmetric and antisymmetric orbit functions which are received from exponential functions by symmetrization and antisymmetrization procedure by means of a Weyl group $W$. The $E$-orbit functions, determined by integral parameters, are invariant withrespect to even part $W^{aff}_{e}$ of the affine Weyl group corresponding to $W$. The $E$-orbit functions determine a symmetrized Fourier transform, where these functions serve as a kernel of the transform. They also determine a transform on a finite set of points of the fundamental domain $F^{e}$ of the group $W^{aff}_{e}$ (the discrete $E$-orbit function transform.

  1. Methods for Characterisation of unknown Suspect Radioactive Samples

    International Nuclear Information System (INIS)

    Sahagia, M.; Grigorescu, E.L.; Luca, A.; Razdolescu, A.C.; Ivan, C.

    2001-01-01

    Full text: The paper presents various identification and measurement methods, used for the expertise of a wide variety of suspect radioactive materials, whose circulation was not legally stated. The main types of examined samples were: radioactive sources, illegally trafficked; suspect radioactive materials or radioactively contaminated devices; uranium tablets; fire detectors containing 241 Am sources; osmium samples containing radioactive 185 Os or enriched 187 Os. The types of analyses and determination methods were as follows: the chemical composition was determined by using identification reagents or by neutron activation analysis; the radionuclide composition was determined by using gamma-ray spectrometry; the activity and particle emission rates were determined by using calibrated radiometric equipment; the absorbed dose rate at the wall of all types of containers and samples was determined by using calibrated dose ratemeters. The radiation exposure risk for population, due to these radioactive materials, was evaluated for every case. (author)

  2. Congenital orbital encephalocele, orbital dystopia, and exophthalmos.

    Science.gov (United States)

    Hwang, Kun; Kim, Han Joon

    2012-07-01

    We present here an exceedingly rare variant of a nonmidline basal encephalocele of the spheno-orbital type, and this was accompanied with orbital dystopia in a 56-year-old man. On examination, his left eye was located more inferolaterally than his right eye, and the patient said this had been this way since his birth. The protrusion of his left eye was aggravated when he is tired. His naked visual acuity was 0.7/0.3, and the ocular pressure was 14/12 mm Hg. The exophthalmometry was 10/14 to 16 mm. His eyeball motion was not restricted, yet diplopia was present in all directions. The distance from the midline to the medial canthus was 20/15 mm. The distance from the midline to the midpupillary line was 35/22 mm. The vertical dimension of the palpebral fissure was 12/9 mm. The height difference of the upper eyelid margin was 11 mm, and the height difference of the lower eyelid margin was 8 mm. Facial computed tomography and magnetic resonance imaging showed left sphenoid wing hypoplasia and herniation of the left anterior temporal pole and dura mater into the orbit, and this resulted into left exophthalmos and encephalomalacia in the left anterior temporal pole. To the best of our knowledge, our case is the second case of basal encephalocele and orbital dystopia.

  3. Computed tomography of the orbital tumors

    International Nuclear Information System (INIS)

    Choi, Jai Korl; Lee, Hwang Bok; Kang, Eun Young; Seol, Hae Young; Suh, Won Hyuck; Ahn, Byeong Yeob

    1987-01-01

    The development of computed tomography (CT) provided a noninvasive safe technique for imaging the orbit in any plane exquisitely demonstrating its normal anatomy as well as its pathologic process. The orbit is an ideal structure to be examined by CT because of large difference of absorption values between the intraorbital fat, muscle, optic nerve and vessels. In this study, the authors reviewed CT findings of 66 pathologically proven orbital tumors and tumorous conditions among the total of 98 cases who had taken orbital CT scan because if exophthalmos, ocular pain, diplopia and other ophthalmologic symptoms suggesting orbital masses during the period of 3 years. For the analysis of characteristic CT findings of the orbital lesions, all lesions are divided into 4 groups according to the site of origin, i.e., tumors arising in the eyeball (group 1); from intraconal space (group 2); from extraconal space (group 3); and from extraorbital regions (group 4). The results are as follows; 1.Extra tumor detection and localization was possible in 63 cases. Thus the detection rate was 95% with CT scan. 2.Among 36 males and 30 females, their age ranged from 10 months to 72 years. 3.Intraocular tumors (group 1) were 10 cases. Retinoblastoma occurred wholly in the young children under 5 years and combined with calcification in 57%. Choroidal melanoma occurred wholly in adults. 4.Intraconal tumors (group 2) were 9 cases. Vascular tumors (7 cases) were the most frequent and well enhancing mass. 5.The tumors arising in the extraconal region (group 3) were pseudotumor (12 cases), lymphoma (3 cases), dermoid cyst (4 cases), metastasis (2 cases), adenoid cystic carcinoma (1 case) and teratoma (1 case). A case of lymphoma demonstrating retrobulbar ill defined mass with scleral l thickening could not be differentiated from the pseudotumor which showing similar finding. 6.The lesions arising from extraorbital region (group 4) were PNS cancer (9 cases), mucocele (3 cases), lid cancer (4

  4. Computed tomography of the orbital tumors

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jai Korl; Lee, Hwang Bok; Kang, Eun Young; Seol, Hae Young; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of); Ahn, Byeong Yeob [Han Mi Hospital, Seoul (Korea, Republic of)

    1987-04-15

    The development of computed tomography (CT) provided a noninvasive safe technique for imaging the orbit in any plane exquisitely demonstrating its normal anatomy as well as its pathologic process. The orbit is an ideal structure to be examined by CT because of large difference of absorption values between the intraorbital fat, muscle, optic nerve and vessels. In this study, the authors reviewed CT findings of 66 pathologically proven orbital tumors and tumorous conditions among the total of 98 cases who had taken orbital CT scan because if exophthalmos, ocular pain, diplopia and other ophthalmologic symptoms suggesting orbital masses during the period of 3 years. For the analysis of characteristic CT findings of the orbital lesions, all lesions are divided into 4 groups according to the site of origin, i.e., tumors arising in the eyeball (group 1); from intraconal space (group 2); from extraconal space (group 3); and from extraorbital regions (group 4). The results are as follows; 1.Extra tumor detection and localization was possible in 63 cases. Thus the detection rate was 95% with CT scan. 2.Among 36 males and 30 females, their age ranged from 10 months to 72 years. 3.Intraocular tumors (group 1) were 10 cases. Retinoblastoma occurred wholly in the young children under 5 years and combined with calcification in 57%. Choroidal melanoma occurred wholly in adults. 4.Intraconal tumors (group 2) were 9 cases. Vascular tumors (7 cases) were the most frequent and well enhancing mass. 5.The tumors arising in the extraconal region (group 3) were pseudotumor (12 cases), lymphoma (3 cases), dermoid cyst (4 cases), metastasis (2 cases), adenoid cystic carcinoma (1 case) and teratoma (1 case). A case of lymphoma demonstrating retrobulbar ill defined mass with scleral l thickening could not be differentiated from the pseudotumor which showing similar finding. 6.The lesions arising from extraorbital region (group 4) were PNS cancer (9 cases), mucocele (3 cases), lid cancer (4

  5. Complex scattering dynamics and the integer quantum Hall effect

    International Nuclear Information System (INIS)

    Trugman, S.A.; Waugh, F.R.

    1987-01-01

    The effect of a magnetic field on potential scattering is investigated microscopically. A magnetic field renders the scattering of a classical charged particle far more complex than previously suspected. Consequences include possible 1/f noise and an explanation of the observed breakdown of the quantum Hall effect at large currents. A particular scatterer is described by a discontinuous one dimensional Hamiltonian map, a class of maps that has not previously been studied. A renormalization group analysis indicates that singular behavior arises from the interplay of electron orbits that are periodic and orbits that are quasiperiodic

  6. Measurement of orbital volume by computed tomography. Especially on the growth of orbit

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Minoru [Fukushima Medical Coll. (Japan)

    2000-10-01

    Using reconstructed X-ray computed tomography (CT) images of serial coronal sections, we measured the orbital volume and studied its changes with age. The subjects consisted of 109 patients (74 males, 35 females) who had undergone X-ray CT. After the reproducibility of orbital volume measurements and laterality in individuals were confirmed, the relation between the orbital volume and the age, sex, weight, and interlateral orbital rim distance were examined. The difference between two measurements in the same patients was 0.4% for measured volume, which showed the reproducibility of this measurement to be good. The laterality in individuals was 0.06 cm{sup 3}: this difference was very small and not significant. The orbital volume showed no unbalance between the right and left at any stage of growth. Both the height and the interlateral orbital rim distance had a strong correlation with the orbital volume. Referring to the relation between age and orbital volume, a strong correlation with an almost identical approximate equation was obtained for both sexes under 12 years of age. Presumably, the rapid growth of the orbit comes to an end by 15 years of age in males and 11 years in females. This means that more than 95% growth of adults has already been completed in the first half of the teens. The mean orbital volume in adult Japanese is 23.6{+-}2.0 (mean{+-}standard deviation) cm{sup 3} in males and 20.9{+-}1.3 cm{sup 3} in females. (author)

  7. Measurement of orbital volume by computed tomography. Especially on the growth of orbit

    International Nuclear Information System (INIS)

    Furuta, Minoru

    2000-01-01

    Using reconstructed X-ray computed tomography (CT) images of serial coronal sections, we measured the orbital volume and studied its changes with age. The subjects consisted of 109 patients (74 males, 35 females) who had undergone X-ray CT. After the reproducibility of orbital volume measurements and laterality in individuals were confirmed, the relation between the orbital volume and the age, sex, weight, and interlateral orbital rim distance were examined. The difference between two measurements in the same patients was 0.4% for measured volume, which showed the reproducibility of this measurement to be good. The laterality in individuals was 0.06 cm 3 : this difference was very small and not significant. The orbital volume showed no unbalance between the right and left at any stage of growth. Both the height and the interlateral orbital rim distance had a strong correlation with the orbital volume. Referring to the relation between age and orbital volume, a strong correlation with an almost identical approximate equation was obtained for both sexes under 12 years of age. Presumably, the rapid growth of the orbit comes to an end by 15 years of age in males and 11 years in females. This means that more than 95% growth of adults has already been completed in the first half of the teens. The mean orbital volume in adult Japanese is 23.6±2.0 (mean±standard deviation) cm 3 in males and 20.9±1.3 cm 3 in females. (author)

  8. Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions.

    Science.gov (United States)

    Callahan, Alison B; Campbell, Ashley A; Petris, Carisa; Kazim, Michael

    Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions. A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case. Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision. The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

  9. AD Leonis: Radial Velocity Signal of Stellar Rotation or Spin–Orbit Resonance?

    Science.gov (United States)

    Tuomi, Mikko; Jones, Hugh R. A.; Barnes, John R.; Anglada-Escudé, Guillem; Butler, R. Paul; Kiraga, Marcin; Vogt, Steven S.

    2018-05-01

    AD Leonis is a nearby magnetically active M dwarf. We find Doppler variability with a period of 2.23 days, as well as photometric signals: (1) a short-period signal, which is similar to the radial velocity signal, albeit with considerable variability; and (2) a long-term activity cycle of 4070 ± 120 days. We examine the short-term photometric signal in the available All-Sky Automated Survey and Microvariability and Oscillations of STars (MOST) photometry and find that the signal is not consistently present and varies considerably as a function of time. This signal undergoes a phase change of roughly 0.8 rad when considering the first and second halves of the MOST data set, which are separated in median time by 3.38 days. In contrast, the Doppler signal is stable in the combined High-Accuracy Radial velocity Planet Searcher and High Resolution Echelle Spectrometer radial velocities for over 4700 days and does not appear to vary in time in amplitude, phase, period, or as a function of extracted wavelength. We consider a variety of starspot scenarios and find it challenging to simultaneously explain the rapidly varying photometric signal and the stable radial velocity signal as being caused by starspots corotating on the stellar surface. This suggests that the origin of the Doppler periodicity might be the gravitational tug of a planet orbiting the star in spin–orbit resonance. For such a scenario and no spin–orbit misalignment, the measured v\\sin i indicates an inclination angle of 15.°5 ± 2.°5 and a planetary companion mass of 0.237 ± 0.047 M Jup.

  10. Stable low-altitude orbits around Ganymede considering a disturbing body in a circular orbit

    Science.gov (United States)

    Cardoso dos Santos, J.; Carvalho, J. P. S.; Vilhena de Moraes, R.

    2014-10-01

    Some missions are being planned to visit Ganymede like the Europa Jupiter System Mission that is a cooperation between NASA and ESA to insert the spacecraft JGO (Jupiter Ganymede Orbiter) into Ganymedes orbit. This comprehension of the dynamics of these orbits around this planetary satellite is essential for the success of this type of mission. Thus, this work aims to perform a search for low-altitude orbits around Ganymede. An emphasis is given in polar orbits and it can be useful in the planning of space missions to be conducted around, with respect to the stability of orbits of artificial satellites. The study considers orbits of artificial satellites around Ganymede under the influence of the third-body (Jupiter's gravitational attraction) and the polygenic perturbations like those due to non-uniform distribution of mass (J_2 and J_3) of the main body. A simplified dynamic model for these perturbations is used. The Lagrange planetary equations are used to describe the orbital motion of the artificial satellite. The equations of motion are developed in closed form to avoid expansions in eccentricity and inclination. The results show the argument of pericenter circulating. However, low-altitude (100 and 150 km) polar orbits are stable. Another orbital elements behaved variating with small amplitudes. Thus, such orbits are convenient to be applied to future space missions to Ganymede. Acknowledgments: FAPESP (processes n° 2011/05671-5, 2012/12539-9 and 2012/21023-6).

  11. Titan Orbiter Aerorover Mission

    Science.gov (United States)

    Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.

    2001-01-01

    We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.

  12. Dynamic and reduced-dynamic precise orbit determination of satellites in low earth orbits

    International Nuclear Information System (INIS)

    Swatschina, P.

    2009-01-01

    The precise positioning of satellites in Low Earth Orbits (LEO) has become a key technology for advanced space missions. Dedicated satellite missions, such as CHAMP, GRACE and GOCE, that aim to map the Earths gravity field and its variation over time with unprecedented accuracy, initiated the demand for highly precise orbit solutions of LEO satellites. Furthermore, a wide range of additional science opportunities opens up with the capability to generate accurate LEO orbits. For all considered satellite missions, the primary measurement system for navigation is a spaceborne GPS receiver. The goal of this thesis is to establish and implement methods for Precise Orbit Determination (POD) of LEO satellites using GPS. Striving for highest precision using yet efficient orbit generation strategies, the attained orbit solutions are aimed to be competitive with the most advanced solutions of other institutions. Dynamic and reduced-dynamic orbit models provide the basic concepts of this work. These orbit models are subsequently adjusted to the highly accurate GPS measurements. The GPS measurements are introduced at the zero difference level in the ionosphere free linear combination. Appropriate procedures for GPS data screening and editing are established to detect erroneous data and to employ measurements of good quality only. For the dynamic orbit model a sophisticated force model, especially designed for LEO satellites, has been developed. In order to overcome the limitations that are induced by the deficiencies of the purely dynamical model, two different types of empirical parameters are introduced into the force model. These reduced-dynamic orbit models allow for the generation of much longer orbital arcs while preserving the spacecraft dynamics to the most possible extent. The two methods for reduced-dynamic orbit modeling are instantaneous velocity changes (pulses) or piecewise constant accelerations. For both techniques highly efficient modeling algorithms are

  13. In situ Orbit Extraction from Live, High Precision Collisionless Simulations of Systems Formed by Cold Collapse

    Science.gov (United States)

    Noriega-Mendoza, H.; Aguilar, L. A.

    2018-04-01

    We performed high precision, N-body simulations of the cold collapse of initially spherical, collisionless systems using the GYRFALCON code of Dehnen (2000). The collapses produce very prolate spheroidal configurations. After the collapse, the systems are simulated for 85 and 170 half-mass radius dynamical timescales, during which energy conservation is better than 0.005%. We use this period to extract individual particle orbits directly from the simulations. We then use the TAXON code of Carpintero and Aguilar (1998) to classify 1 to 1.5% of the extracted orbits from our final, relaxed configurations: less than 15% are chaotic orbits, 30% are box orbits and 60% are tube orbits (long and short axis). Our goal has been to prove that direct orbit extraction is feasible, and that there is no need to "freeze" the final N-body system configuration to extract a time-independent potential.

  14. Extra-appendiceal findings in pediatric abdominal CT for suspected appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Halverson, Mark; Delgado, Jorge; Mahboubi, Soroosh [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2014-07-15

    Much has been written regarding the incidence, types, importance and management of abdominal CT incidental findings in adults, but there is a paucity of literature on incidental findings in children. We sought to determine the prevalence and characteristics of extra-appendiceal and incidental findings in pediatric abdominal CT performed for suspected appendicitis. A retrospective review was performed of abdominal CT for suspected appendicitis in a pediatric emergency department from July 2010 to June 2012. Extra-appendiceal findings were recorded. Any subsequent imaging was noted. Extra-appendiceal findings were divided into incidental findings of doubtful clinical significance, alternative diagnostic findings potentially providing a diagnosis other than appendicitis explaining the symptoms, and incidental findings that were abnormalities requiring clinical correlation and sometimes requiring further evaluation but not likely related to the patient symptoms. One hundred sixty-five children had abdominal CT for suspected appendicitis. Seventy-seven extra-appendiceal findings were found in 57 (34.5%) patients. Most findings (64 of 77) were discovered in children who did not have appendicitis. Forty-one of these findings (53%) could potentially help explain the patient's symptoms, while 30 of the findings (39%) were abnormalities that were unlikely to be related to the symptoms but required clinical correlation and sometimes further work-up. Six of the findings (8%) had doubtful or no clinical significance. Extra-appendiceal findings are common in children who undergo abdominal CT in the setting of suspected appendicitis. A significant percentage of these patients have findings that help explain their symptoms. Knowledge of the types and prevalence of these findings may help radiologists in the planning and interpretation of CT examinations in this patient population. (orig.)

  15. Suspected placenta accreta and cesarean hysterectomy: observational cohort utilizing an intraoperative decision strategy.

    Science.gov (United States)

    Weiniger, Carolyn F; Kabiri, Doron; Ginosar, Yehuda; Ezra, Yossef; Shachar, BatZion; Lyell, Deirdre J

    2016-03-01

    Planned cesarean hysterectomy (CH) is recommended to minimize morbidity for suspected placenta accreta (PA), yet this ends fertility. We examined CH frequency and post-operative morbidities for suspected PA cases when an intra-operative decision strategy to perform CH was used. Suspected PA cases were pre-operatively identified in one tertiary care center. Women were assessed intra-operatively, prior to uterine incision, for immediate CH or for attempted placental separation. We compared outcomes among women with versus without PA (surgical and/or pathologic diagnosis), and examined outcomes following immediate CH versus attempted placental separation. Our cohort, from 2002 to 2012, comprised 99 women with suspected PA; 54 (54.5%) had PA diagnosed by surgery/pathology, and 45 (45.5%) did not. Among women diagnoses surgically or pathologically with PA, CH was performed for 46/54 (85%); 8 women with suspected PA had successful placental separation. 27 of the 46 CH were performed immediately following uterine wall examination and 19 were performed following attempted placental separation. We received histological confirmation of the clinical placenta accreta diagnosis for 24/46 (52.2%) cases, and in 22/46 (47.8%) cases the histology did not confirm the clinical diagnosis. Surgery duration, packed cell transfusion requirement and postoperative outcomes were similar among women with PA regardless of immediate CH versus attempted placental separation, except for a higher cystotomy rates following attempted placental separation. Emergency deliveries were performed at significantly earlier gestational ages. Among women with suspected PA, an intra-operative CH decision allows some women to avoid CH. Consideration of attempted placental separation did not increase blood transfusion or post-operative complications, but was associated with a higher rate of cystotomy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

    Science.gov (United States)

    Kim, Kyoung-Whan; Lee, Kyung-Jin; Sinova, Jairo; Lee, Hyun-Woo; Stiles, M. D.

    2017-09-01

    We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal-metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism.

  17. Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

    Science.gov (United States)

    Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

    2017-11-01

    The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

  18. Autism spectrum disorder symptoms in juvenile suspects of sex offenses.

    Science.gov (United States)

    't Hart-Kerkhoffs, Lisette A; Jansen, Lucres M; Doreleijers, Theo A; Vermeiren, Robert; Minderaa, Ruud B; Hartman, Catharina A

    2009-02-01

    To investigate autism spectrum disorder (ASD) symptoms in juvenile suspects of sex offenses. A group of 175 juvenile suspected sex offenders (all males, mean +/- SD age = 14.9 +/- 1.4 years) was compared with a matched healthy control group (N = 500, mean +/- SD age = 14.0 +/- 1.4 years) and a group of children with DSM-IV-diagnosed ASD (N = 114, mean +/- SD age = 14.2 +/- 1.9 years) with respect to autistic symptoms as measured by means of a standardized questionnaire, the Children's Social Behavior Questionnaire. Furthermore, specific subgroups of sexual offenders, i.e., child molesters, solo peer offenders, and group offenders, were compared with regard to levels of ASD symptoms. The study was conducted from May 2003 to December 2006. Significantly higher levels of ASD symptoms were found in juvenile sex offenders than in healthy controls, while levels were lower than in the ASD group (F = 148.259, p symptoms than group offenders (F = 5.127, p symptoms are higher in juvenile suspects of sex offenses as compared to the healthy population, which argues for considering specific diagnostic assessment in this population, especially in solo offenders and child molesters. Copyright 2009 Physicians Postgraduate Press, Inc.

  19. Application of X-Ray Pulsar Navigation: A Characterization of the Earth Orbit Trade Space

    Science.gov (United States)

    Yu, Wayne Hong

    2016-01-01

    The potential for pulsars as a navigation source has been studied since their discovery in 1967. X-ray pulsar navigation (XNAV) is a celestial navigation system that uses the consistent timing nature of x-ray photons from millisecond pulsars (MSP) to perform space navigation. By comparing the detected arrival of x-ray photons to a reference database of expected pulsar light-curve timing models, one can infer a range and range rate measurement based on light time delay. Much of the challenge of XNAV comes from the faint signal, availability, and distant nature of pulsars. This is a study of potential pulsar XNAV measurements to measure extended Kalman filter (EKF) tracking performance with a wide trade space of bounded Earth orbits, using a simulation of existing x-ray detector space hardware. An example of an x-ray detector for XNAV is the NASA Station Explorer for X-ray Timing and Navigation (SEXTANT) mission, a technology demonstration of XNAV set to perform on the International Space Station (ISS) in late 2016early 2017. XNAV hardware implementation is driven by trajectory and environmental influences which add noise to the x-ray pulse signal. In a closed Earth orbit, the radiation environment can exponentially increase the signal noise from x-ray pulsar sources, decreasing the quality and frequency of measurements. The SEXTANT mission in particular improves on the signal to noise ratio by focusing an array of 56 x-ray silicon drift detectors at one pulsar target at a time. This reduces timing glitches and other timing noise contributions from ambient x-ray sources to within a 100 nanosecond resolution. This study also considers the SEXTANT scheduling challenges inherent in a single target observation. Finally, as the navigation sources are now relatively inertial targets, XNAV measurements are also subject to periods of occultation from various celestial bodies. This study focuses on the characterization of these drivers in closed Earth orbits and is not a

  20. Detection of the lunar body tide by the Lunar Orbiter Laser Altimeter.

    Science.gov (United States)

    Mazarico, Erwan; Barker, Michael K; Neumann, Gregory A; Zuber, Maria T; Smith, David E

    2014-04-16

    The Lunar Orbiter Laser Altimeter instrument onboard the Lunar Reconnaissance Orbiter spacecraft collected more than 5 billion measurements in the nominal 50 km orbit over ∼10,000 orbits. The data precision, geodetic accuracy, and spatial distribution enable two-dimensional crossovers to be used to infer relative radial position corrections between tracks to better than ∼1 m. We use nearly 500,000 altimetric crossovers to separate remaining high-frequency spacecraft trajectory errors from the periodic radial surface tidal deformation. The unusual sampling of the lunar body tide from polar lunar orbit limits the size of the typical differential signal expected at ground track intersections to ∼10 cm. Nevertheless, we reliably detect the topographic tidal signal and estimate the associated Love number h 2 to be 0.0371 ± 0.0033, which is consistent with but lower than recent results from lunar laser ranging. Altimetric data are used to create radial constraints on the tidal deformationThe body tide amplitude is estimated from the crossover dataThe estimated Love number is consistent with previous estimates but more precise.