WorldWideScience

Sample records for eccentrically perturbed tonks-girardeau

  1. Interfaces between Bose-Einstein and Tonks-Girardeau atomic gases

    OpenAIRE

    Filatrella, Giovanni; Malomed, Boris A.

    2015-01-01

    We consider one-dimensional mixtures of an atomic Bose-Einstein condensate (BEC) and Tonks- Giradeau (TG) gas. The mixture is modeled by a coupled system of the Gross-Pitaevskii equation for the BEC and the quintic nonlinear Schroedinger equation for the TG component. An immiscibility condition for the binary system is derived in a general form. Under this condition, three types of BEC-TG interfaces are considered: domain walls (DWs) separating the two components; bubble-drops (BDs), in the f...

  2. Crystalline phases of bosons in rotating traps: Tonks-Girardeau gas on a ring.

    Science.gov (United States)

    Romanovsky, Igor; Yannouleas, Constantine; Landman, Uzi

    2006-03-01

    We analyze the systems of strongly repelling bosons in two-dimensional harmonic and ring-shaped traps as a function of the rotational frequency of the trap for neutral atoms (and of an applied magnetic field for charged bosons). Our two-step approach consists of breaking the rotational symmetry at the Hartree-Fock level and of subsequent symmetry restoration via projection techniques, thus taking into account correlations beyond the Gross-Pitaevskii (GP) solution. The bosons localize and form crystalline patterns both for a repulsive contact potential and a Coulomb interaction, as revealed via conditional probability distribution (CPD) analysis. This behavior of the bosons in the ring-shaped traps in the strong repulsion limit is similar to the behavior of fermions and is a manifestation of the fermionization phenomenon. We present calculations for the ground state energies as a function of the rotational frequency (or the strength of the magnetic field) and as a function of the repulsion strength. Phys. Rev. Lett.93, 230405 (2004)

  3. Non-numeric computation for high eccentricity orbits. [Earth satellite orbit perturbation

    Science.gov (United States)

    Sridharan, R.; Renard, M. L.

    1975-01-01

    Geocentric orbits of large eccentricity (e = 0.9 to 0.95) are significantly perturbed in cislunar space by the sun and moon. The time-history of the height of perigee, subsequent to launch, is particularly critical. The determination of 'launch windows' is mostly concerned with preventing the height of perigee from falling below its low initial value before the mission lifetime has elapsed. Between the extremes of high accuracy digital integration of the equations of motion and of using an approximate, but very fast, stability criteria method, this paper is concerned with the developement of a method of intermediate complexity using non-numeric computation. The computer is used as the theory generator to generalize Lidov's theory using six osculating elements. Symbolic integration is completely automatized and the output is a set of condensed formulae well suited for repeated applications in launch window analysis. Examples of applications are given.

  4. Extreme secular excitation of eccentricity inside mean motion resonance. Small bodies driven into star-grazing orbits by planetary perturbations

    Science.gov (United States)

    Pichierri, Gabriele; Morbidelli, Alessandro; Lai, Dong

    2017-09-01

    Context. It is well known that asteroids and comets fall into the Sun. Metal pollution of white dwarfs and transient spectroscopic signatures of young stars like β-Pic provide growing evidence that extra solar planetesimals can attain extreme orbital eccentricities and fall into their parent stars. Aims: We aim to develop a general, implementable, semi-analytical theory of secular eccentricity excitation of small bodies (planetesimals) in mean motion resonances with an eccentric planet valid for arbitrary values of the eccentricities and including the short-range force due to General Relativity. Methods: Our semi-analytic model for the restricted planar three-body problem does not make use of series expansion and therefore is valid for any eccentricity value and semi-major axis ratio. The model is based on the application of the adiabatic principle, which is valid when the precession period of the longitude of pericentre of the planetesimal is much longer than the libration period in the mean motion resonance. In resonances of order larger than 1 this is true except for vanishingly small eccentricities. We provide prospective users with a Mathematica notebook with implementation of the model allowing direct use. Results: We confirm that the 4:1 mean motion resonance with a moderately eccentric (e' ≲ 0.1) planet is the most powerful one to lift the eccentricity of planetesimals from nearly circular orbits to star-grazing ones. However, if the planet is too eccentric, we find that this resonance is unable to pump the planetesimal's eccentricity to a very high value. The inclusion of the General Relativity effect imposes a condition on the mass of the planet to drive the planetesimals into star-grazing orbits. For a planetesimal at 1 AU around a solar mass star (or white dwarf), we find a threshold planetary mass of about 17 Earth masses. We finally derive an analytical formula for this critical mass. Conclusions: Planetesimals can easily fall into the central star

  5. THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. II. KOI-1474.01, A CANDIDATE ECCENTRIC PLANET PERTURBED BY AN UNSEEN COMPANION

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Rebekah I.; Murray-Clay, Ruth A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, MS-10, Cambridge, MA 02138 (United States); Johnson, John Asher; Morton, Timothy D. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, California 95064 (United States); Howard, Andrew W., E-mail: rdawson@cfa.harvard.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)

    2012-12-20

    The exoplanets known as hot Jupiters-Jupiter-sized planets with periods of less than 10 days-likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. argued that high eccentricity migration (HEM) mechanisms proposed for situating these close-in planets should produce an observable population of highly eccentric proto-hot Jupiters that have not yet tidally circularized. HEM should also create failed-hot Jupiters, with periapses just beyond the influence of fast circularization. Using the technique we previously presented for measuring eccentricities from photometry (the ''photoeccentric effect''), we are distilling a collection of eccentric proto- and failed-hot Jupiters from the Kepler Objects of Interest (KOI). Here, we present the first, KOI-1474.01, which has a long orbital period (69.7340 days) and a large eccentricity e 0.81{sup +0.10}{sub -0.07}, skirting the proto-hot Jupiter boundary. Combining Kepler photometry, ground-based spectroscopy, and stellar evolution models, we characterize host KOI-1474 as a rapidly rotating F star. Statistical arguments reveal that the transiting candidate has a low false-positive probability of 3.1%. KOI-1474.01 also exhibits transit-timing variations of the order of an hour. We explore characteristics of the third-body perturber, which is possibly the ''smoking-gun'' cause of KOI-1474.01's large eccentricity. We use the host star's period, radius, and projected rotational velocity to measure the inclination of the stellar spin. Comparing KOI 1474.01's inclination, we find that its orbit is marginally consistent with being aligned with the stellar spin axis, although a reanalysis is warranted with future additional data. Finally, we discuss how the number and existence of proto-hot Jupiters will not only demonstrate that hot Jupiters migrate via HEM, but also shed light on the typical timescale for the mechanism.

  6. WARM JUPITERS NEED CLOSE ''FRIENDS'' FOR HIGH-ECCENTRICITY MIGRATION—A STRINGENT UPPER LIMIT ON THE PERTURBER'S SEPARATION

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Subo [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Road 5, Hai Dian District, Beijing 100871 (China); Katz, Boaz; Socrates, Aristotle [Institute for Advanced Study, 1 Einstein Dr., Princeton, NJ 08540 (United States)

    2014-01-20

    We propose a stringent observational test on the formation of warm Jupiters (gas-giant planets with 10 days ≲ P ≲ 100 days) by high-eccentricity (high-e) migration mechanisms. Unlike hot Jupiters, the majority of observed warm Jupiters have pericenter distances too large to allow efficient tidal dissipation to induce migration. To access the close pericenter required for migration during a Kozai-Lidov cycle, they must be accompanied by a strong enough perturber to overcome the precession caused by general relativity, placing a strong upper limit on the perturber's separation. For a warm Jupiter at a ∼ 0.2 AU, a Jupiter-mass (solar-mass) perturber is required to be ≲ 3 AU (≲ 30 AU) and can be identified observationally. Among warm Jupiters detected by radial velocities (RVs), ≳ 50% (5 out of 9) with large eccentricities (e ≳ 0.4) have known Jovian companions satisfying this necessary condition for high-e migration. In contrast, ≲ 20% (3 out of 17) of the low-e (e ≲ 0.2) warm Jupiters have detected additional Jovian companions, suggesting that high-e migration with planetary perturbers may not be the dominant formation channel. Complete, long-term RV follow-ups of the warm-Jupiter population will allow a firm upper limit to be put on the fraction of these planets formed by high-e migration. Transiting warm Jupiters showing spin-orbit misalignments will be interesting to apply our test. If the misalignments are solely due to high-e migration as commonly suggested, we expect that the majority of warm Jupiters with low-e (e ≲ 0.2) are not misaligned, in contrast with low-e hot Jupiters.

  7. Impurity states in the one-dimensional Bose gas

    Science.gov (United States)

    Pastukhov, Volodymyr

    2017-10-01

    The detailed study of the low-energy spectrum for a mobile impurity in the one-dimensional bosonic environment is performed. Particularly we have considered only two analytically accessible limits, namely, the case of an impurity immersed in a dilute Bose gas where one can use many-body perturbative techniques for low-dimensional bosonic systems and the case of the Tonks-Girardeau gas for which the usual fermionic diagrammatic expansion up to the second order is applied.

  8. Eccentric exercise

    DEFF Research Database (Denmark)

    Kjaer, Michael; Heinemeier, Katja Maria

    2014-01-01

    Eccentric exercise can influence tendon mechanical properties and matrix protein synthesis. mRNA for collagen and regulatory factors thereof are upregulated in animal tendons, independent of muscular contraction type, supporting the view that tendon, compared with skeletal muscle, is less sensitive...

  9. 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.

  10. Introducing Earth's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2015-01-01

    Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

  11. Moderately eccentric warm Jupiters from secular interactions with exterior companions

    Science.gov (United States)

    Anderson, Kassandra R.; Lai, Dong

    2017-12-01

    Recent studies have proposed that most warm Jupiters (WJs, giant planets with semi-major axes in the range of 0.1-1 AU) probably form in-situ, or arrive in their observed orbits through disk migration. However, both in-situ formation and disk migration, in their simplest flavors, predict WJs to be in low-eccentricity orbits, in contradiction with many observed WJs that are moderately eccentric (e=0.2-0.7). This paper examines the possibility that the WJ eccentricities are raised by secular interactions with exterior giant planet companions, following in-situ formation or migration on a circular orbit. Eccentricity growth may arise from an inclined companion (through Lidov-Kozai cycles), or from an eccentric, nearly coplanar companion (through apsidal precession resonances). We quantify the necessary conditions (in terms of the eccentricity, semi-major axis and inclination) for external perturbers of various masses to raise the WJ eccentricity. We also consider the sample of eccentric WJs with detected outer companions, and for each system, identify the range of mutual inclinations needed to generate the observed eccentricity. For most systems, we find that relatively high inclinations (at least $\\sim 40^\\circ$) are needed so that Lidov-Kozai cycles are induced; the observed outer companions are typically not sufficiently eccentric to generate the observed WJ eccentricity in a low-inclination configuration. The results of this paper place constraints on possibly unseen external companions to eccentric WJs. Observations that probe mutual inclinations of giant planet systems will help clarify the origin of eccentric WJs and the role of external companions.

  12. Eccentric, nonspinning, inspiral, Gaussian-process merger approximant for the detection and characterization of eccentric binary black hole mergers

    Science.gov (United States)

    Huerta, E. A.; Moore, C. J.; Kumar, Prayush; George, Daniel; Chua, Alvin J. K.; Haas, Roland; Wessel, Erik; Johnson, Daniel; Glennon, Derek; Rebei, Adam; Holgado, A. Miguel; Gair, Jonathan R.; Pfeiffer, Harald P.

    2018-01-01

    We present ENIGMA, a time domain, inspiral-merger-ringdown waveform model that describes nonspinning binary black holes systems that evolve on moderately eccentric orbits. The inspiral evolution is described using a consistent combination of post-Newtonian theory, self-force and black hole perturbation theory. Assuming eccentric binaries that circularize prior to coalescence, we smoothly match the eccentric inspiral with a stand-alone, quasicircular merger, which is constructed using machine learning algorithms that are trained with quasicircular numerical relativity waveforms. We show that ENIGMA reproduces with excellent accuracy the dynamics of quasicircular compact binaries. We validate ENIGMA using a set of Einstein Toolkit eccentric numerical relativity waveforms, which describe eccentric binary black hole mergers with mass-ratios between 1 ≤q ≤5.5 , and eccentricities e0≲0.2 ten orbits before merger. We use this model to explore in detail the physics that can be extracted with moderately eccentric, nonspinning binary black hole mergers. In particular, we use ENIGMA to show that the gravitational wave transients GW150914, GW151226, GW170104, GW170814 and GW170608 can be effectively recovered with spinning, quasicircular templates if the eccentricity of these events at a gravitational wave frequency of 10 Hz satisfies e0≤{0.175 ,0.125 ,0.175 ,0.175 ,0.125 }, respectively. We show that if these systems have eccentricities e0˜0.1 at a gravitational wave frequency of 10 Hz, they can be misclassified as quasicircular binaries due to parameter space degeneracies between eccentricity and spin corrections. Using our catalog of eccentric numerical relativity simulations, we discuss the importance of including higher-order waveform multipoles in gravitational wave searches of eccentric binary black hole mergers.

  13. Eccentricity from transit photometry

    DEFF Research Database (Denmark)

    Van Eylen, Vincent; Albrecht, Simon

    2015-01-01

    and can be described by a Rayleigh distribution with $\\sigma$ = 0.049 $\\pm$ 0.013. This is in full agreement with solar system eccentricities, but in contrast to the eccentricity distributions previously derived for exoplanets from radial velocity studies. Our findings are helpful in identifying which...... (TTVs), and we present some previously unreported TTVs. Finally transit durations help distinguish between false positives and true planets and we use our measurements to confirm six new exoplanets....

  14. Virtual Proprioception for eccentric training.

    Science.gov (United States)

    LeMoyne, Robert; Mastroianni, Timothy

    2017-07-01

    Wireless inertial sensors enable quantified feedback, which can be applied to evaluate the efficacy of therapy and rehabilitation. In particular eccentric training promotes a beneficial rehabilitation and strength training strategy. Virtual Proprioception for eccentric training applies real-time feedback from a wireless gyroscope platform enabled through a software application for a smartphone. Virtual Proprioception for eccentric training is applied to the eccentric phase of a biceps brachii strength training and contrasted to a biceps brachii strength training scenario without feedback. During the operation of Virtual Proprioception for eccentric training the intent is to not exceed a prescribed gyroscope signal threshold based on the real-time presentation of the gyroscope signal, in order to promote the eccentric aspect of the strength training endeavor. The experimental trial data is transmitted wireless through connectivity to the Internet as an email attachment for remote post-processing. A feature set is derived from the gyroscope signal for machine learning classification of the two scenarios of Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback. Considerable classification accuracy is achieved through the application of a multilayer perceptron neural network for distinguishing between the Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback.

  15. Can Eccentric Debris Disks Be Long-lived? A First Numerical Investigation and Application to Zeta(exp 2) Reticuli

    Science.gov (United States)

    Faramaz, V.; Beust, H.; Thebault, P.; Augereau, J.-C.; Bonsor, A.; delBurgo, C.; Ertel, S.; Marshall, J. P.; Milli, J.; Montesinos, B.; hide

    2014-01-01

    Context. Imaging of debris disks has found evidence for both eccentric and offset disks. One hypothesis is that they provide evidence for massive perturbers, for example, planets or binary companions, which sculpt the observed structures. One such disk was recently observed in the far-IR by the Herschel Space Observatory around Zeta2 Reticuli. In contrast with previously reported systems, the disk is significantly eccentric, and the system is several Gyr old. Aims. We aim to investigate the long-term evolution of eccentric structures in debris disks caused by a perturber on an eccentric orbit around the star. We hypothesise that the observed eccentric disk around Zeta2 Reticuli might be evidence of such a scenario. If so, we are able to constrain the mass and orbit of a potential perturber, either a giant planet or a binary companion. Methods. Analytical techniques were used to predict the effects of a perturber on a debris disk. Numerical N-body simulations were used to verify these results and further investigate the observable structures that may be produced by eccentric perturbers. The long-term evolution of the disk geometry was examined, with particular application to the Zeta2 Reticuli system. In addition, synthetic images of the disk were produced for direct comparison with Herschel observations. Results. We show that an eccentric companion can produce both the observed offsets and eccentric disks. These effects are not immediate, and we characterise the timescale required for the disk to develop to an eccentric state (and any spirals to vanish). For Zeta2 Reticuli, we derive limits on the mass and orbit of the companion required to produce the observations. Synthetic images show that the pattern observed around Zeta2 Reticuli can be produced by an eccentric disk seen close to edge-on, and allow us to bring additional constraints on the disk parameters of our model (disk flux and extent). Conclusions. We conclude that eccentric planets or stellar companions

  16. SUPER-ECCENTRIC MIGRATING JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Socrates, Aristotle; Katz, Boaz; Dong Subo; Tremaine, Scott [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2012-05-10

    An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e = 0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e > 0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is a-dot {proportional_to}a{sup 1/2} and consequently the number distribution satisfies dN/d log a{proportional_to}a{sup 1/2}. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios.

  17. Eccentric binaries of compact objects in strong-field gravity

    Energy Technology Data Exchange (ETDEWEB)

    Gold, Roman

    2011-09-27

    In this thesis we study the dynamics as well as the resulting gravitational radiation from eccentric binaries of compact objects in the non-linear regime of General Relativity. For this purpose we solve Einstein's field equation numerically in a 3+1 decomposition using the moving-puncture technique. We focus our study on very particular orbits, arising as a purely relativistic phenomenon of the two-body problem in General Relativity, which are associated with unstable circular orbits. They are governed by a fast, nearly circular revolution at a short distance followed by a slow, radial motion on a nearly elliptic trajectory. Due to the unique features of their orbital trajectories they are called zoom-whirl orbits. We analyze how the peculiar dynamics manifests itself in the emitted gravitational radiation and to which extent one can infer the orbital properties from observations of the gravitational waves. In the first part, we consider black hole binaries. We perform a comprehensive parameter study by varying the initial eccentricity, computing and characterizing the resulting gravitational waveforms. We address aspects, which can only be obtained from non-perturbative methods, and which are crucial to the astrophysical relevance of these orbits. In particular, our results imply a fairly low amount of fine-tuning necessary to spot zoom-whirl effects. We find whirl orbits for values of the eccentricities, which fall in disjunct intervals extending to rather low values. Furthermore, we show that whirl effects just before merger cause a signal with significant amplitude. In the second part, we investigate neutron star binaries on eccentric orbits in full General Relativity, which has not been studied so far. We explore their phenomenology and study the consequences for the matter after the neutron stars have merged. In these evolutions the merged neutron stars sooner or later collapse to form a black hole. During the collapse most of the matter is accreted on

  18. A new kinematical definition of orbital eccentricity

    Directory of Open Access Journals (Sweden)

    Ninković S.

    2009-01-01

    Full Text Available A new concept of orbital eccentricity is given. The dimensionless quantities proposed in the present paper to serve as orbital eccentricities have a kinematical nature. The purpose is to use them in describing the motion for the case of three-dimensional orbits. A comparison done for nearly planar orbits shows that the values of the eccentricities proposed here do not differ significantly from those corresponding to the eccentricities of geometric nature usually applied.

  19. Neptune's Eccentricity and the Nature of the Kuiper Belt

    Science.gov (United States)

    Ward, William R.; Hahn, Joseph M.

    1998-01-01

    The small eccentricity of Neptune may be a direct consequence of apsidal wave interaction with the trans-Neptune population of debris called the Kuiper belt. The Kuiper belt is subject to resonant perturbations from Neptune, so that the transport of angular momentum by density waves can result in orbital evolution of Neptune as well as changes in the structure of the Kuiper belt. In particular, for a belt eroded out to the vicinity of Neptune's 2:1 resonance at about 48 astronomical units, Neptune's eccentricity can damp to its current value over the age of the solar system if the belt contains slightly more than an earth mass of material out to about 75 astronomical units.

  20. ECCENTRIC JUPITERS VIA DISK–PLANET INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Duffell, Paul C.; Chiang, Eugene, E-mail: duffell@berkeley.edu, E-mail: echiang@astro.berkeley.edu [Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley (United States)

    2015-10-20

    Numerical hydrodynamics calculations are performed to determine the conditions under which giant planet eccentricities can be excited by parent gas disks. Unlike in other studies, Jupiter-mass planets are found to have their eccentricities amplified—provided their orbits start off as eccentric. We disentangle the web of co-rotation, co-orbital, and external resonances to show that this finite-amplitude instability is consistent with that predicted analytically. Ellipticities can grow until they reach of order of the disk's aspect ratio, beyond which the external Lindblad resonances that excite eccentricity are weakened by the planet's increasingly supersonic epicyclic motion. Forcing the planet to still larger eccentricities causes catastrophic eccentricity damping as the planet collides into gap walls. For standard parameters, the range of eccentricities for instability is modest; the threshold eccentricity for growth (∼0.04) is not much smaller than the final eccentricity to which orbits grow (∼0.07). If this threshold eccentricity can be lowered (perhaps by non-barotropic effects), and if the eccentricity driving documented here survives in 3D, it may robustly explain the low-to-moderate eccentricities ≲0.1 exhibited by many giant planets (including Jupiter and Saturn), especially those without planetary or stellar companions.

  1. 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.

  2. Introducing the Moon's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2014-11-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a guided exercise, rather than just telling them the facts.1 The inclination and nodes may be found by direct observation, monitoring carefully the position of the Moon among the stars. Even the regression of the nodes may be discovered in this way2 To find the eccentricity from students' observations is also possible,3 but that requires considerable time and effort. if a whole class should discover it in a short time, here is a method more suitable for a one-day class or home assignment. The level I aim at is, more or less, advanced high school or first-year college students. I assume them to be acquainted with celestial coordinates and the lunar phases, and to be able to use algebra and trigonometry.

  3. Eccentric crank variable compression ratio mechanism

    Science.gov (United States)

    Lawrence, Keith Edward [Kobe, JP; Moser, William Elliott [Peoria, IL; Roozenboom, Stephan Donald [Washington, IL; Knox, Kevin Jay [Peoria, IL

    2008-05-13

    A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

  4. Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats

    DEFF Research Database (Denmark)

    Kongsgaard, M; Aagaard, P; Roikjaer, S

    2006-01-01

    Recent studies have shown excellent clinical results using eccentric squat training on a 25 degrees decline board to treat patellar tendinopathy. It remains unknown why therapeutic management of patellar tendinopathy using decline eccentric squats offer superior clinical efficacy compared to stan...... to standard horizontal eccentric squats. This study aimed to compare electromyography activity, patellar tendon strain and joint angle kinematics during standard and decline eccentric squats....

  5. Spectral signatures of disk eccentricity in young binary systems. I. Circumprimary case

    Science.gov (United States)

    Regály, Zs.; Sándor, Zs.; Dullemond, C. P.; Kiss, L. L.

    2011-04-01

    Context. Star formation occurs via fragmentation of molecular clouds, which means that the majority of stars born are members of binary systems. There is growing evidence that planets might form in circumprimary disks of medium-separation (≲50 AU) binaries. The tidal forces caused by the secondary generally act to distort the originally circular circumprimary disk to an eccentric one. Since the disk eccentricity might play a major role in planet formation, it is of great importance to understand how it evolves. Aims: We investigate disk eccentricity evolution to reveal its dependence on the physical parameters of the binary system and the protoplanetary disk. To infer the disk eccentricity from high-resolution near-IR spectroscopy, we calculate the fundamental band (4.7 μm) emission lines of the CO molecule emerging from the atmosphere of the eccentric disk. Methods: We model circumprimary disk evolution under the gravitational perturbation of the orbiting secondary using a 2D grid-based hydrodynamical code, assuming α-type viscosity. The hydrodynamical results are combined with our semianalytical spectral code to calculate the CO molecular line profiles. Our thermal disk model is based on the double-layer disk model approximation. We assume LTE and canonical dust and gas properties for the circumprimary disk. Results: We find that the orbital velocity distribution of the gas parcels differs significantly from the circular Keplerian fashion. The line profiles are double-peaked and asymmetric in shape. The magnitude of asymmetry is insensitive to the binary mass ratio, the magnitude of viscosity (α), and the disk mass. In contrast, the disk eccentricity, thus the magnitude of the line profile asymmetry, is influenced significantly by the binary eccentricity and the disk geometrical thickness. Conclusions: We demonstrate that the disk eccentricity profile in the planet-forming region can be determined by fitting the high-resolution CO line profile asymmetry

  6. Eccentricity distribution in the main asteroid belt

    Science.gov (United States)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  7. PERTURBATIVE QCD

    OpenAIRE

    I. Hinchliffe

    2010-01-01

    This is the written version of a set of lectures on perturbative QCD that were delivered to a mixed audience of young theorists and experimentalists in the course of the XXII International Meeting on Fundamental Physics. These notes are virtually a verbatim transcription of the lectures. The selection of topics is somewhat arbitrary, but two basic points are emphasized: the rationale behind QCD and how ongoing experiments, such as those taking place in LEP and HERA, contribute to our understa...

  8. Collisions and drag in debris discs with eccentric parent belts

    Science.gov (United States)

    Löhne, T.; Krivov, A. V.; Kirchschlager, F.; Sende, J. A.; Wolf, S.

    2017-08-01

    Context. High-resolution images of circumstellar debris discs reveal off-centred rings that indicate past or ongoing perturbation, possibly caused by secular gravitational interaction with unseen stellar or substellar companions. The purely dynamical aspects of this departure from radial symmetry are well understood. However, the observed dust is subject to additional forces and effects, most notably collisions and drag. Aims: To complement the studies of dynamics, we therefore aim to understand how the addition of collisional evolution and drag forces creates new asymmetries and strengthens or overrides existing ones. Methods: We augmented our existing numerical code Analysis of Collisional Evolution (ACE) by an azimuthal dimension, the longitude of periapse. A set of fiducial discs with global eccentricities ranging from 0 to 0.4 was evolved over gigayear timescales. Size distribution and spatial variation of dust were analysed and interpreted. We discuss the basic impact of belt eccentricity on spectral energy distributions and images. Results: We find features imposed on characteristic timescales. First, radiation pressure defines size cut-offs that differ between periapse and apoapse, resulting in an asymmetric halo. The differences in size distribution make the observable asymmetry of the halo depend on wavelength. Second, collisional equilibrium prefers smaller grains on the apastron side of the parent belt, reducing the effect of pericentre glow and the overall asymmetry. Third, Poynting-Robertson drag fills the region interior to an eccentric belt such that the apastron side is more tenuous. Interpretation and prediction of the appearance in scattered light is problematic when spatial and size distribution are coupled.

  9. Eccentric exercise in treatment of Achilles tendinopathy

    DEFF Research Database (Denmark)

    Nørregaard, J; Larsen, C C; Bieler, T

    2007-01-01

    Prognosis and treatment of Achilles tendon pain (achillodynia) has been insufficiently studied. The purpose of the present study was to examine the long-term effect of eccentric exercises compared with stretching exercises on patients with achillodynia....

  10. Eccentric Exercise to Enhance Neuromuscular Control.

    Science.gov (United States)

    Lepley, Lindsey K; Lepley, Adam S; Onate, James A; Grooms, Dustin R

    Neuromuscular alterations are a major causal factor of primary and secondary injuries. Though injury prevention programs have experienced some success, rates of injuries have not declined, and after injury, individuals often return to activity with functionality below clinical recommendations. Considering alternative therapies to the conventional concentric exercise approach, such as one that can target neuromuscular injury risk and postinjury alterations, may provide for more effective injury prevention and rehabilitation protocols. Peer-reviewed sources available on the Web of Science and MEDLINE databases from 2000 through 2016 were gathered using searches associated with the keywords eccentric exercise, injury prevention, and neuromuscular control. Eccentric exercise will reduce injury risk by targeting specific neural and morphologic alterations that precipitate neuromuscular dysfunction. Clinical review. Level 4. Neuromuscular control is influenced by alterations in muscle morphology and neural activity. Eccentric exercise beneficially modifies several underlying factors of muscle morphology (fiber typing, cross-sectional area, working range, and pennation angle), and emerging evidence indicates that eccentric exercise is also beneficial to peripheral and central neural activity (alpha motorneuron recruitment/firing, sarcolemma activity, corticospinal excitability, and brain activation). There is mounting evidence that eccentric exercise is not only a therapeutic intervention influencing muscle morphology but also targets unique alterations in neuromuscular control, influencing injury risk.

  11. Dynamics of short eccentric plain seals with high axial Reynolds number. [for Space Shuttle engine hydrogen fuel turbopump

    Science.gov (United States)

    Allaire, P. E.; Lee, C. C.; Gunter, E. J.

    1978-01-01

    Plain seals with high axial flow rates produce large stiffness and damping coefficients that can help stabilize high-speed rotating machinery. When the shaft is eccentric in the seal, a Bernoulli effect low-pressure region occurs on the large-clearance side of the shaft. A fluid-restoring force tends to center the shaft and reduce vibrations. This work extends the previous theory for short plain centered seals to large eccentricities using a perturbation analysis. Surface roughness effects are also included. An analysis of seals used in the Space Shuttle main engine hydrogen fuel turbopump indicates the desirability of plain seals over the labyrinth type. Experimental results confirm this.

  12. Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats.

    Science.gov (United States)

    Kongsgaard, M; Aagaard, P; Roikjaer, S; Olsen, D; Jensen, M; Langberg, H; Magnusson, S P

    2006-08-01

    Recent studies have shown excellent clinical results using eccentric squat training on a 25 degrees decline board to treat patellar tendinopathy. It remains unknown why therapeutic management of patellar tendinopathy using decline eccentric squats offer superior clinical efficacy compared to standard horizontal eccentric squats. This study aimed to compare electromyography activity, patellar tendon strain and joint angle kinematics during standard and decline eccentric squats. Thirteen subjects performed unilateral eccentric squats on flat-and a 25 degrees decline surface. During the squats, electromyography activity was obtained in eight representative muscles. Also, ankle, knee and hip joint goniometry was obtained. Additionally, patellar tendon strain was measured in vivo using ultrasonography as subjects maintained a unilateral isometric 90 degrees knee angle squat position on either flat or 25 degrees decline surface. Patellar tendon strain was significantly greater (Pcompared to the standard surface. The stop angles of the ankle and hip joints were significantly smaller during the decline compared to the standard squats (Pcompared to the standard squats (Pstandard and decline squats. The use of a 25 degrees decline board increases the load and the strain of the patellar tendon during unilateral eccentric squats. This finding likely explains previous reports of superior clinical efficacy of decline eccentric squats in the rehabilitative management of patellar tendinopathy.

  13. Eccentric connectivity index and eccentric distance sum of some graph operations

    Directory of Open Access Journals (Sweden)

    Buzohragul Eskender

    2013-03-01

    Full Text Available Let $G=(V,E$ be a connected graph. The eccentric connectivity index of $G$, $xi^{c}(G$, is defined as $xi^{c}(G=sum_{vin V(G}deg(vec(v$, where $deg(v$ is the degree of a vertex $v$ and $ec(v$ is its eccentricity. The eccentric distance sum of $G$ is defined as $xi^{d}(G=sum_{vin V(G}ec(vD(v$, where $D(v=sum_{uin V(G}d_{G}(u,v$ and $d_{G}(u,v$ is the distance between $u$ and $v$ in $G$. In this paper, we calculate the eccentric connectivity index and eccentric distance sum of generalized hierarchical product of graphs. Moreover, we present explicit formulae for the eccentric connectivity index of $F$-sum graphs in terms of some invariants of the factors. As applications, we present exact formulae for the values of the eccentric connectivity index of some graphs of chemical interest such as $C_{4}$ nanotubes, $C_{4}$ nanotoris and hexagonal chains.

  14. Tropical sea surface temperatures and the earth's orbital eccentricity cycles

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.; Fernandes, A.A.; Mohan, R.

    cyclicities at ~100- and ~400-ka corresponding to the Earth's orbital eccentricity cycles. Results, therefore imply that the tropical Indian Ocean warm pool persisted during the Quaternary and the paleo-SSTs fluctuating at the orbital eccentricity frequencies...

  15. First and Second Zagreb Eccentricity Indices of Thorny Graphs

    Directory of Open Access Journals (Sweden)

    Nazeran Idrees

    2017-01-01

    Full Text Available The Zagreb eccentricity indices are the eccentricity reformulation of the Zagreb indices. Let H be a simple graph. The first Zagreb eccentricity index ( E 1 ( H is defined to be the summation of squares of the eccentricity of vertices, i.e., E 1 ( H = ∑ u ∈ V ( H Ɛ H 2 ( u . The second Zagreb eccentricity index ( E 2 ( H is the summation of product of the eccentricities of the adjacent vertices, i.e., E 2 ( H = ∑ u v ∈ E ( H Ɛ H ( u Ɛ H ( v . We obtain the thorny graph of a graph H by attaching thorns i.e., vertices of degree one to every vertex of H . In this paper, we will find closed formulation for the first Zagreb eccentricity index and second Zagreb eccentricity index of different well known classes of thorny graphs.

  16. Negating the Yearly Eccentricity Magnitude Variation of Super-synchronous Disposal Orbits due to Solar Radiation Pressure

    Science.gov (United States)

    Jones, S. L.

    Solar radiation pressure alters satellites' eccentricity by accelerating and decelerating them during each orbit. The accumulated perturbation cancels yearly for geostationary satellites, but meanwhile the perigee radius changes. Disposed satellites must be reorbited higher to compensate, using more fuel. The examined disposal orbit points toward the Sun and uses the satellite's natural eccentricity. This causes the eccentricity vector to only change direction, keeping the perigee radius constant. This thesis verifies this behavior over one year with an analytical derivation and MATLAB simulation, gaining useful insights into its cause. The traditional and proposed disposal orbits are then modeled using NASA's GMAT for more realistic simulations. The proposed orbit's sensitivity to satellite and initialization errors is also examined. Relationships are developed to show these errors' effect on the perigee radius. In conclusion, while this orbit can be used in the short term, margins are necessary to guarantee protection of the geostationary belt.

  17. Electromyographic comparison of concentric and eccentric ...

    African Journals Online (AJOL)

    The study was conducted to compare the Electromyographic (EMG) activity variation of contractions (concentric and eccentric) during three different abdominal exercises (sit-up) exercises on rectus abdominal (upper and lower rectus). The sit-up exercises were: straight leg sit-up, bent leg sit-up and crunches. The EMG ...

  18. Eccentric-orbit EMRI gravitational wave energy fluxes to 7PN order

    CERN Document Server

    Forseth, Erik; Hopper, Seth

    2015-01-01

    We present new results through 7PN order on the energy flux from eccentric extreme-mass-ratio binaries. The black hole perturbation calculations are made at very high accuracy (200 decimal places) using a Mathematica code based on the Mano-Suzuki-Takasugi (MST) analytic function expansion formalism. All published coefficients in the expansion through 3PN order are confirmed and new analytic and numeric terms are found to high order in $e^2$ at orders between 3.5PN and 7PN. We also show original work in finding (nearly) arbitrarily accurate expansions for hereditary terms at 1.5PN, 2.5PN, and 3PN orders. We fit to a model where at each PN order an eccentricity singular function is factored out, improving substantially the fit even as $e \\to 1$.

  19. Effects of Retinal Eccentricity on Human Manual Control

    Science.gov (United States)

    Popovici, Alexandru; Zaal, Peter M. T.

    2017-01-01

    This study investigated the effects of viewing a primary flight display at different retinal eccentricities on human manual control behavior and performance. Ten participants performed a pitch tracking task while looking at a simplified primary flight display at different horizontal and vertical retinal eccentricities, and with two different controlled dynamics. Tracking performance declined at higher eccentricity angles and participants behaved more nonlinearly. The visual error rate gain increased with eccentricity for single-integrator-like controlled dynamics, but decreased for double-integrator-like dynamics. Participants' visual time delay was up to 100 ms higher at the highest horizontal eccentricity compared to foveal viewing. Overall, vertical eccentricity had a larger impact than horizontal eccentricity on most of the human manual control parameters and performance. Results might be useful in the design of displays and procedures for critical flight conditions such as in an aerodynamic stall.

  20. Patterns in exoplanet count and eccentricity distributions

    Science.gov (United States)

    Taylor, Stuart F.

    2018-01-01

    The distribution of exoplanets of contains an unexpected level of features, starting with an unexpected gap the splits the main pileup of much of the planet population. In the population of planets of metal-rich sunlike single stars (SLSS objects), which comprises 40% of planets found by the radial velocity method, when counting logarithmic periods the main pileup of planets with periods longer than 100 days is split into two peaks separated by a significant gap. There is a wide region which has so few planets that none are found in the current data set. We show that this gap is extremely unlikely to occur by random. Because this gap is well-filled among planets of low surface gravity and low metallicity stars with 31 objects, it is unlikely that the bimodal nature of the metal rich SLSS population is due to observational effects. Comparisons of eccentricity of the metal-rich and metal-poor SLSS populations depend strongly on the two-peak-gap structure of counts of the metal-rich SLSS (rSLSS) population. Consideration of these features is essential to properly study the correlations of eccentricity with other planet-system parameters given how the eccentricity of rSLSS objects is highest in the two peaks of the rSLSS population.

  1. Vibroacoustic response of an eccentric hollow cylinder

    Science.gov (United States)

    Hasheminejad, Seyyed M.; Mousavi-akbarzadeh, Hessam

    2012-07-01

    The linear 3D elasticity theory in conjunction with the classical method of separation of variables and the translational addition theorem for cylindrical wave functions are employed to investigate the three-dimensional steady-state sound radiation characteristics of an arbitrarily thick eccentric hollow cylinder of infinite length, submerged in an unbounded ideal acoustic medium, and subjected to arbitrary time-harmonic on-surface mechanical drives. The spatial Fourier transform along the shell axis and Fourier series expansion in the circumferential direction are utilized to obtain a formal integral expression for the radiated pressure field in the frequency domain. The method of stationary phase is subsequently implemented to evaluate the integral for an observation point in the far field. The analytical results are illustrated with numerical examples in which air-filled water-submerged concentric and eccentric steel cylinders are driven by harmonic concentrated radial and transverse surface loads. Effects of excitation and cylinder eccentricity on the far-field radiated pressure amplitudes/directivities are discussed and contributions from pseudo-Rayleigh, whispering gallery, and axially guided waves are examined through selected spatial dispersion patterns. Limiting cases are considered and the validity of results is established with the aid of a commercial finite element package as well as by comparison with the data in the existing literature.

  2. Eccentric Contraction-Induced Muscle Fibre Adaptation

    Directory of Open Access Journals (Sweden)

    Arabadzhiev T. I.

    2009-12-01

    Full Text Available Hard-strength training induces strength increasing and muscle damage, especially after eccentric contractions. Eccentric contractions also lead to muscle adaptation. Symptoms of damage after repeated bout of the same or similar eccentrically biased exercises are markedly reduced. The mechanism of this repeated bout effect is unknown. Since electromyographic (EMG power spectra scale to lower frequencies, the adaptation is related to neural adaptation of the central nervous system (CNS presuming activation of slow-non-fatigable motor units or synchronization of motor unit firing. However, the repeated bout effect is also observed under repeated stimulation, i.e. without participation of the CNS. The aim of this study was to compare the possible effects of changes in intracellular action potential shape and in synchronization of motor units firing on EMG power spectra. To estimate possible degree of the effects of central and peripheral changes, interferent EMG was simulated under different intracellular action potential shapes and different degrees of synchronization of motor unit firing. It was shown that the effect of changes in intracellular action potential shape and muscle fibre propagation velocity (i.e. peripheral factors on spectral characteristics of EMG signals could be stronger than the effect of synchronization of firing of different motor units (i.e. central factors.

  3. Obliquity and Eccentricity Constraints for Terrestrial Exoplanets

    Science.gov (United States)

    Kane, Stephen R.; Torres, Stephanie M.

    2017-11-01

    Exoplanet discoveries over recent years have shown that terrestrial planets are exceptionally common. Many of these planets are in compact systems that result in complex orbital dynamics. A key step toward determining the surface conditions of these planets is understanding the latitudinally dependent flux incident at the top of the atmosphere as a function of orbital phase. The two main properties of a planet that influence the time-dependent nature of the flux are the obliquity and orbital eccentricity of the planet. We derive the criterion for which the flux variation due to obliquity is equivalent to the flux variation due to orbital eccentricity. This equivalence is computed for both the maximum and average flux scenarios, the latter of which includes the effects of the diurnal cycle. We apply these calculations to four known multi-planet systems (GJ 163, K2-3, Kepler-186, and Proxima Centauri), where we constrain the eccentricity of terrestrial planets using orbital dynamics considerations and model the effect of obliquity on incident flux. We discuss the implications of these simulations on climate models for terrestrial planets and outline detectable signatures of planetary obliquity.

  4. Third-Body Perturbation Using a Single Averaged Model: Application in Nonsingular Variables

    Directory of Open Access Journals (Sweden)

    Carlos Renato Huaura Solórzano

    2007-01-01

    Full Text Available The Lagrange's planetary equations written in terms of the classical orbital elements have the disadvantage of singularities in eccentricity and inclination. These singularities are due to the mathematical model used and do not have physical reasons. In this paper, we studied the third-body perturbation using a single averaged model in nonsingular variables. The goal is to develop a semianalytical study of the perturbation caused in a spacecraft by a third body using a single averaged model to eliminate short-period terms caused by the motion of the spacecraft. This is valid if no resonance occurs with the moon or the sun. Several plots show the time histories of the Keplerian elements of equatorial and circular orbits, which are the situations with singularities. In this paper, the expansions are limited only to second order in eccentricity and for the ratio of the semimajor axis of the perturbing and perturbed bodies and to the fourth order for the inclination.

  5. Relevance of ellipse eccentricity for camera calibration

    Science.gov (United States)

    Mordwinzew, W.; Tietz, B.; Boochs, F.; Paulus, D.

    2015-05-01

    Plane circular targets are widely used within calibrations of optical sensors through photogrammetric set-ups. Due to this popularity, their advantages and disadvantages are also well studied in the scientific community. One main disadvantage occurs when the projected target is not parallel to the image plane. In this geometric constellation, the target has an elliptic geometry with an offset between its geometric and its projected center. This difference is referred to as ellipse eccentricity and is a systematic error which, if not treated accordingly, has a negative impact on the overall achievable accuracy. The magnitude and direction of eccentricity errors are dependent on various factors. The most important one is the target size. The bigger an ellipse in the image is, the bigger the error will be. Although correction models dealing with eccentricity have been available for decades, it is mostly seen as a planning task in which the aim is to choose the target size small enough so that the resulting eccentricity error remains negligible. Besides the fact that advanced mathematical models are available and that the influence of this error on camera calibration results is still not completely investigated, there are various additional reasons why bigger targets can or should not be avoided. One of them is the growing image resolution as a by-product from advancements in the sensor development. Here, smaller pixels have a lower S/N ratio, necessitating more pixels to assure geometric quality. Another scenario might need bigger targets due to larger scale differences whereas distant targets should still contain enough information in the image. In general, bigger ellipses contain more contour pixels and therefore more information. This supports the target-detection algorithms to perform better even at non-optimal conditions such as data from sensors with a high noise level. In contrast to rather simple measuring situations in a stereo or multi-image mode, the impact

  6. The Eccentric Kozai-Lidov Mechanism for Outer Test Particle

    Science.gov (United States)

    Naoz, Smadar; Li, Gongjie; Zanardi, Macarena; de Elía, Gonzalo Carlos; Di Sisto, Romina P.

    2017-07-01

    The secular approximation of the hierarchical three body systems has been proven to be very useful in addressing many astrophysical systems, from planets to stars to black holes. In such a system, two objects are on a tight orbit and the tertiary is on a much wider orbit. Here, we study the dynamics of a system by taking the tertiary mass to zero and solve the hierarchical three body system up to the octupole level of approximation. We find a rich dynamics that the outer orbit undergoes due to gravitational perturbations from the inner binary. The nominal result of the precession of the nodes is mostly limited for the lowest order of approximation; however, when the octupole level of approximation is introduced, the system becomes chaotic, as expected, and the tertiary oscillates below and above 90°, similarly to the non-test particle flip behavior. We provide the Hamiltonian of the system and investigate the dynamics of the system from the quadrupole to the octupole level of approximations. We also analyze the chaotic and quasi-periodic orbital evolution by studying the surfaces of sections. Furthermore, including general relativity, we showcase the long-term evolution of individual debris disk particles under the influence of a far-away interior eccentric planet. We show that this dynamics can naturally result in retrograde objects and a puffy disk after a long timescale evolution (a few Gyr) for initially aligned configuration.

  7. The Eccentric Kozai–Lidov Mechanism for Outer Test Particle

    Energy Technology Data Exchange (ETDEWEB)

    Naoz, Smadar [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Li, Gongjie [Harvard Smithsonian Center for Astrophysics, Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States); Zanardi, Macarena; De Elía, Gonzalo Carlos; Di Sisto, Romina P., E-mail: snaoz@astro.ucla.edu [Instituto de Astrofísica de La Plata, CCT La Plata-CONICET-UNLP Paseo del Bosque S/N (1900), La Plata (Argentina)

    2017-07-01

    The secular approximation of the hierarchical three body systems has been proven to be very useful in addressing many astrophysical systems, from planets to stars to black holes. In such a system, two objects are on a tight orbit and the tertiary is on a much wider orbit. Here, we study the dynamics of a system by taking the tertiary mass to zero and solve the hierarchical three body system up to the octupole level of approximation. We find a rich dynamics that the outer orbit undergoes due to gravitational perturbations from the inner binary. The nominal result of the precession of the nodes is mostly limited for the lowest order of approximation; however, when the octupole level of approximation is introduced, the system becomes chaotic, as expected, and the tertiary oscillates below and above 90°, similarly to the non-test particle flip behavior. We provide the Hamiltonian of the system and investigate the dynamics of the system from the quadrupole to the octupole level of approximations. We also analyze the chaotic and quasi-periodic orbital evolution by studying the surfaces of sections. Furthermore, including general relativity, we showcase the long-term evolution of individual debris disk particles under the influence of a far-away interior eccentric planet. We show that this dynamics can naturally result in retrograde objects and a puffy disk after a long timescale evolution (a few Gyr) for initially aligned configuration.

  8. Satellite formation design in orbits of high eccentricity for missions with performance criteria specified over a region of interest

    Science.gov (United States)

    Roscoe, Christopher William Thomas

    Several methods are presented for the design of satellite formations for science missions in high-eccentricity reference orbits with quantifiable performance criteria specified throughout only a portion the orbit, called the Region of Interest (RoI). A modified form of the traditional average along-track drift minimization condition is introduced to account for the fact that performance criteria are only specified within the RoI, and a robust formation design algorithm (FDA) is defined to improve performance in the presence of formation initialization errors. Initial differential mean orbital elements are taken as the design variables and the Gim-Alfriend state transition matrix (G-A STM) is used for relative motion propagation. Using mean elements and the G-A STM allows for explicit inclusion of J2 perturbation effects in the design process. The methods are applied to the complete formation design problem of the NASA Magnetospheric Multiscale (MMS) mission and results are verified using the NASA General Mission Analysis Tool (GMAT). Since satellite formations in high-eccentricity orbits will spend long times at high altitude, third-body perturbations are an important design consideration as well. A detailed analytical analysis of third-body perturbation effects on satellite formations is also performed and averaged dynamics are derived for the particular case of the lunar perturbation. Numerical results of the lunar perturbation analysis are obtained for the example application of the MMS mission and verified in GMAT.

  9. THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. III. A PAUCITY OF PROTO-HOT JUPITERS ON SUPER-ECCENTRIC ORBITS

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Rebekah I. [Department of Astronomy, University of California, Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States); Murray-Clay, Ruth A.; Johnson, John Asher, E-mail: rdawson@berkeley.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States)

    2015-01-10

    Gas giant planets orbiting within 0.1 AU of their host stars are unlikely to have formed in situ and are evidence for planetary migration. It is debated whether the typical hot Jupiter smoothly migrated inward from its formation location through the proto-planetary disk, or was perturbed by another body onto a highly eccentric orbit, which tidal dissipation subsequently shrank and circularized during close stellar passages. Socrates and collaborators predicted that the latter model should produce a population of super-eccentric proto-hot Jupiters readily observable by Kepler. We find a paucity of such planets in the Kepler sample, which is inconsistent with the theoretical prediction with 96.9% confidence. Observational effects are unlikely to explain this discrepancy. We find that the fraction of hot Jupiters with an orbital period P > 3 days produced by the star-planet Kozai mechanism does not exceed (at two-sigma) 44%. Our results may indicate that disk migration is the dominant channel for producing hot Jupiters with P > 3 days. Alternatively, the typical hot Jupiter may have been perturbed to a high eccentricity by interactions with a planetary rather than stellar companion, and began tidal circularization much interior to 1 AU after multiple scatterings. A final alternative is that early in the tidal circularization process at high eccentricities tidal circularization occurs much more rapidly than later in the process at low eccentricities, although this is contrary to current tidal theories.

  10. Truss Joint with Positive Eccentricity Experimental Research

    Directory of Open Access Journals (Sweden)

    Gordziej-Zagórowska Małgorzata

    2017-06-01

    Full Text Available Due to the technological reasons in modern lightweight steel trusses, fabricated from cold-formed sections, positive eccentricities appear in the truss nodes what induce additional forces in the truss chords. To account for the real load-carrying capacity of truss node area the steel structure research in scale 1:1 were conducted. The experiments consisted of two parts: preliminary and proper one, when conclusions from the first part were applied. Carrying out preliminary studies helped to identify of the research station drawbacks and eliminate most of them, what ensure the appropriate research results. The initial numerical analysis were also conducted what was presented in the paper.

  11. Modelling very-high-eccentricity asteroidal librations with the Andoyer Hamiltonian.

    Science.gov (United States)

    Simula, A.; Ferraz-Mello, S.; Giordano, C.

    High eccentricity asteroidal librations are modelled using a tailored Hamiltonian which is built from the high eccentricity non planar asymmetric expansion (Roig et al. 1998). We show that, using the reducing Sessin's rotation, the Hamiltonian of the pseudo circular model is actually a first order Andoyer Hamiltonian. This Hamiltonian has already been used by Henrard, at least for a numerical study, as a second fundamental model for resonance. A different approach was followed by Ferraz-Mello, who carried on the integration of the equations of motion in formal way by the use of the Jacobian elliptic functions. This second approach permits an explicit description of the asteroidal dynamics combined with a very precise analytical computation of the frequencies. We use this analytical approach for the study of asteroidal librations. Secular perturbations of the perturber's orbit can also be considered in the dynamics, together with the short periodic variations of Jupiter's orbit associated to the 5/2 near-commensurability between Jupiter and Saturn. Some preliminary results are shown.

  12. LAGEOS II perigee rate and eccentricity vector excitations residuals and the Yarkovsky-Schach effect

    Science.gov (United States)

    Lucchesi, David M.; Ciufolini, Ignazio; Andrés, José I.; Pavlis, Erricos C.; Peron, Roberto; Noomen, Ron; Currie, Douglas G.

    2004-07-01

    We have analysed LAGEOS II perigee rate and eccentricity vector excitation residuals over a period of about 7.8 years, adjusting and computing the satellite orbit with the full set of dynamical models included in the GEODYN II software code. The long-term behaviour of these orbital residuals appears to be characterised by several distinct frequencies which are a clear signature of the Yarkovsky-Schach perturbing effect. This non-gravitational perturbation is not included in the GEODYN II models for the orbit determination and analysis. Through an independent numerical analysis, and using the new LOSSAM model to represent the spin-axis behaviour of the satellite, we propagated the Yarkovsky-Schach effect on LAGEOS II perigee rate and compared the results obtained with the orbital residuals. We have thus been able to satisfactorily fit the amplitude of the Yarkovsky-Schach effect to the observed residuals. Our approach here has proven very successful with very positive results. We have been able to obtain a fractional reduction of about 40% of the post-fit rms with respect to the pre-fit value. When analysing the eccentricity vector residuals, we have been able to obtain a better result in the case of the real component, with a fractional reduction of the post-fit rms of about 49% of the initial value. The analysis of the effect's imaginary component in the eccentricity vector rate is more complicated and deserves additional scrutiny. In this case we need a deeper study which includes the analysis of other unmodelled and mismodelled effects acting on the imaginary component. The study performed in this paper will be of significant relevance not only for the geophysical applications involving LAGEOS II orbit analysis, but also for a refined re-analysis of the general relativistic precession produced by the Earth angular momentum, i.e., the Lense-Thirring effect.

  13. Moderate Load Eccentric Exercise; A Distinct Novel Training Modality.

    Science.gov (United States)

    Hoppeler, Hans

    2016-01-01

    Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400-500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20-30 min. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al., 2014). It is distinct from plyometric exercises (i.e., drop jumps) that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW) has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically 4-fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2, and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular the rehabilitation after anterior cruciate

  14. Moderate load eccentric exercise; a distinct novel training modality

    Directory of Open Access Journals (Sweden)

    Hans Hoppeler

    2016-11-01

    Full Text Available Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial three weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400-500W in rehabilitative settings and over 1200W in elite athletes. Training is typically carried out 3 times per week for durations of 20-30 minutes. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al. 2014 (LaStayo et al., 2014. It is distinct from plyometric exercises (i.e. drop jumps that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically four fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2 and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular

  15. Normative values of eccentric hip abduction strength in novice runners

    DEFF Research Database (Denmark)

    Ramskov, D; Pedersen, M B; Kastrup, K

    2014-01-01

    PURPOSE: Low eccentric strength of the hip abductors, might increase the risk of patellofemoral pain syndrome and iliotibial band syndrome in runners. No normative values for maximal eccentric hip abduction strength have been established. Therefore the purpose of this study was to establish norma...

  16. Response of electrostatic probes to eccentric charge distributions

    DEFF Research Database (Denmark)

    Johansson, Torben; McAllister, Iain Wilson

    2001-01-01

    The response of an electrostatic probe mounted in an electrode is examined with reference to eccentric charge distributions. The study involves using the probe λ function to derive a characteristic parameter. This parameter enables the response of the probe to different degrees of eccentricity...

  17. detection of static eccentricity fault in saturated induction motors

    African Journals Online (AJOL)

    2013-06-30

    Jun 30, 2013 ... Key Words: Induction motor, static eccentricity (SE), time stepping finite elements (TSFE) method ... machines eccentricity usually occurs due to the build-up of tolerances during manufacturing stage [6]. Fig. 1. ... In 1988 the Time Stepping Finite Element (TSFE) technique proposed by researchers of GEC.

  18. Flow Mode Magnetorheological Dampers with an Eccentric Gap

    Directory of Open Access Journals (Sweden)

    Young-Tai Choi

    2014-07-01

    Full Text Available This paper analyzes flow mode magnetorheological (MR dampers with an eccentric annular gap (i.e., a nonuniform annular gap. To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and damping coefficient, which is the ratio of equivalent viscous field-on damping to field-off damping. In addition, damper capabilities of flow mode MR dampers with an eccentric gap were compared to a concentric gap (i.e., uniform annular gap.

  19. Eccentric exercise decreases maximal insulin action in humans

    DEFF Research Database (Denmark)

    Asp, Svend; Daugaard, J R; Kristiansen, S

    1996-01-01

    ) necessary to maintain euglycaemia during maximal insulin stimulation was lower during PEC compared with CC (15.7%, 81.3 +/- 3.2 vs. 96.4 +/- 8.8 mumol kg-1 min-1, P 2 days after unaccustomed eccentric exercise, muscle and whole-body insulin action is impaired at maximal...... subjects participated in two euglycaemic clamps, performed in random order. One clamp was preceded 2 days earlier by one-legged eccentric exercise (post-eccentric exercise clamp (PEC)) and one was without the prior exercise (control clamp (CC)). 2. During PEC the maximal insulin-stimulated glucose uptake...... over the eccentric thigh was marginally lower when compared with the control thigh, (11.9%, 64.6 +/- 10.3 vs. 73.3 +/- 10.2 mumol kg-1 min-1, P = 0.08), whereas no inter-thigh difference was observed at a submaximal insulin concentration. The glycogen concentration was lower in the eccentric thigh...

  20. Automated Lattice Perturbation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Monahan, Christopher

    2014-11-01

    I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.

  1. Cross-education strength and activation after eccentric exercise.

    Science.gov (United States)

    Lepley, Lindsey K; Palmieri-Smith, Riann M

    2014-01-01

    After injury, eccentric exercise of the injured limb is often contraindicated. Cross-education training, whereby the uninvolved limb is exercised, is an alternative that may improve quadriceps muscle strength and activation in the unexercised limb. To determine the effect of eccentric exercise on quadriceps strength and activation gains in the unexercised limb. Eighteen healthy individuals were randomly assigned to an eccentric training group or a control group. Quadriceps strength and activation measures were collected at preintervention, midintervention, and postintervention. Eccentric training participants exercised their dominant limb with a dynamometer in eccentric mode at 60°/s, 3 times per week for 8 weeks. Quadriceps strength was quantified at 30° and 60°/s in concentric and eccentric modes. Quadriceps activation was assessed using the burst superimposition technique and quantified via the central activation ratio. A 2 × 3 repeated-measures analysis of variance was used to detect the effects of group and testing session on quadriceps strength and activation. Where appropriate, post hoc Bonferroni multiple-comparisons procedures were used. We found greater eccentric strength in the unexercised limbs of eccentric training participants between preintervention and midintervention and between preintervention and postintervention (preintervention to midintervention: 30°/s P = .05; preintervention to postintervention: 30°/s P = .02, 60°/s P = .02). No differences were noted in concentric strength (P > .05). An overall trend toward greater quadriceps activation in the unexercised knee was detected between preintervention and postintervention (P = .063), with the eccentric training group demonstrating a strong effect (Cohen d = 0.83). Control strength did not change (P > .05). Exercising with eccentric actions resulted in mode-specific and velocity-specific gains in quadriceps strength in the unexercised limb. A trend toward greater quadriceps activation in

  2. Neural inhibition during maximal eccentric and concentric quadriceps contraction: effects of resistance training

    DEFF Research Database (Denmark)

    Aagaard, Per; Simonsen, E.B.; Andersen, J.L.

    2000-01-01

    neuromuscular activation, muscle strength, neural efferent drive, eccentric activation deficiency, force inhibition......neuromuscular activation, muscle strength, neural efferent drive, eccentric activation deficiency, force inhibition...

  3. Relationships between eccentric hip isokinetic torque and functional performance.

    Science.gov (United States)

    Baldon, Rodrigo de Marche; Lobato D, Ferreira Moreira; Carvalho, Lívia Pinheiro; Wun P, Yan Lam; Presotti, Cátia Valéria; Serrão, Fábio Viadanna

    2012-02-01

    Recently, attention in sports has been given to eccentric hip-muscle function, both in preventing musculoskeletal injuries and improving performance. To determine the key isokinetic variables of eccentric hip torque that predict the functional performance of women in the single-leg triple long jump (TLJ) and the timed 6-m single-leg hop (TH). Within-subject correlational study. Musculoskeletal laboratory. 32 healthy women age 18-25 y. The participants performed 2 sets of 5 eccentric hip-abductor/adductor and lateral/medial-rotator isokinetic contractions (30°/s) and 3 attempts in the TLJ and TH. The independent variables were the eccentric hip-abductor and -adductor and medial- and lateral-rotator isokinetic peak torque, normalized according to body mass (Nm/kg). The dependent variables were the longest distance achieved in the TLJ normalized according to body height and the shortest time spent during the execution of the TH. The forward-stepwise-regression analysis showed that the combination of the eccentric hip lateral-rotator and -abductor isokinetic peak torque provided the most efficient estimate of both functional tests, explaining 65% of the TLJ variance (P < .001) and 55% of the TH variance (P < .001). Higher values for eccentric hip lateral-rotator and hip-abductor torques reflected better performance. Thus, the eccentric action of these muscles should be considered in the development of physical training programs that aim to increase functional performance.

  4. Angle-specific eccentric hamstring fatigue after simulated soccer.

    Science.gov (United States)

    Cohen, Daniel D; Zhao, Bingnan; Okwera, Brian; Matthews, Martyn J; Delextrat, Anne

    2015-04-01

    To evaluate the effect of simulated soccer on the hamstrings eccentric torque-angle profile and angle of peak torque (APTeccH), and on the hamstrings:quadriceps torque ratio at specific joint angles (ASHecc:Qcon). The authors assessed dominant-limb isokinetic concentric and eccentric knee flexion and concentric knee extension at 120°/s in 9 semiprofessional male soccer players immediately before and after they completed the Loughborough Intermittent Shuttle Test (LIST). The LIST resulted in significant decreases in eccentric hamstrings torque at 60°, 50°, and 10° and a significant (21.8%) decrease in ASHecc:Qcon at 10° (P soccer results in a selective loss of eccentric hamstrings torque and hamstrings-to-quadriceps muscle balance at an extended joint position and a shift in the eccentric hamstrings APT to a shorter length, changes that could increase vulnerability to hamstrings injury. These findings suggest that injury-risk screening could be improved by evaluating the eccentric hamstrings torque-angle profile and hamstrings strength-endurance and that the development of hamstrings fatigue resistance and long-length eccentric strength may reduce injury incidence.

  5. Effect of the 6PBT stirrer eccentricity and off-bottom clearance on mixing of pseudoplastic fluid in a stirred tank

    Science.gov (United States)

    Luan, Deyu; Zhang, Shengfeng; Wei, Xing; Duan, Zhenya

    The aim of this work is to investigate the effect of the shaft eccentricity on the flow field and mixing characteristics in a stirred tank with the novel stirrer composed of perturbed six-bent-bladed turbine (6PBT). The difference between coaxial and eccentric agitations is studied using computational fluid dynamics (CFD) simulations combined with standard k-ε turbulent equations, that offer a complete image of the three-dimensional flow field. In order to determine the capability of CFD to forecast the mixing process, particle image velocimetry (PIV), which provide an accurate representation of the time-averaged velocity, was used to measure fluid velocity. The test liquid used was 1.25% (wt) xanthan gum solution, a pseudoplastic fluid with a yield stress. The comparison of the experimental and simulated mean flow fields has demonstrated that calculations based on Reynolds-averaged Navier-Stokes equations are suitable for obtaining accurate results. The effects of the shaft eccentricity and the stirrer off-bottom distance on the flow model, mixing time and mixing efficiency were extensively analyzed. It is observed that the microstructure of the flow field has a significant effect on the tracer mixing process. The eccentric agitation can lead to the flow model change and the non-symmetric flow structure, which would possess an obvious superiority of mixing behavior. Moreover, the mixing rate and mixing efficiency are dependent on the shaft eccentricity and the stirrer off-bottom distance, showing the corresponding increase of the eccentricity with the off-bottom distance. The efficient mixing process of pseudoplastic fluid stirred by 6PBT impeller is obtained with the considerably low mixing energy per unit volume when the stirrer off-bottom distance, C, is T/3 and the eccentricity, e, is 0.2. The research results provide valuable references for the improvement of pseudoplastic fluid agitation technology.

  6. Normative values of eccentric hip abduction strength in novice runners

    DEFF Research Database (Denmark)

    Jørgensen, Daniel Ramskov; Pedersen, Mette Broen; Kastrup, Kristrian

    2014-01-01

    normative values of maximal eccentric hip abduction strength in novice runners. METHODS: Novice healthy runners (n = 831) were recruited through advertisements at a hospital and a university. Maximal eccentric hip abduction strength was measured with a hand-held dynamometer. The demographic variables...... associated with maximal eccentric hip abduction strength from a univariate analysis were included in a multivariate linear regression model. Based on the results from the regression model, a regression equation for normative hip abduction strength is presented. RESULTS: A SIGNIFICANT DIFFERENCE IN MAXIMAL...

  7. The Torsional Eccentricity of the Structures in Miscellaneous Design Codes

    Directory of Open Access Journals (Sweden)

    Ioana Olteanu

    2010-03-01

    Full Text Available Structures rarely achieve structural symmetry. Even in symmetric structures, the asymmetric position of the structural components tends to produce an effective asymmetric structure. Such an asymmetry even if is small, can produce a torsional response coupled with translational response. In the torsional analysis, the provisions of the seismic norms are based on determining the static eccentricity. In this paper is presented a general way of computing the eccentricity in torsional design. The purpose of this article is to make a comparison of the general rules used to determine the eccentricity and their values. Are taken into account the norms from: Romania, Europe, Japan, Germany and the United States of America.

  8. Detection and Characterization of Extrasolar Planets through Mean-motion Resonances. II. The Effect of the Planet’s Orbital Eccentricity on Debris Disk Structures

    Science.gov (United States)

    Tabeshian, Maryam; Wiegert, Paul A.

    2017-09-01

    Structures observed in debris disks may be caused by gravitational interaction with planetary or stellar companions. These perturbed disks are often thought to indicate the presence of planets and offer insights into the properties of both the disk and the perturbing planets. Gaps in debris disks may indicate a planet physically present within the gap, but such gaps can also occur away from the planet’s orbit at mean-motion resonances (MMRs), and this is the focus of our interest here. We extend our study of planet-disk interaction through MMRs, presented in an earlier paper, to systems in which the perturbing planet has moderate orbital eccentricity, a common occurrence in exoplanetary systems. In particular, a new result is that the 3:1 MMR becomes distinct at higher eccentricity, while its effects are absent for circular planetary orbits. We also only consider gravitational interaction with a planetary body of at least 1 M J. Our earlier work shows that even a 1 Earth mass planet can theoretically open an MMR gap; however, given the narrow gap that can be opened by a low-mass planet, its observability would be questionable. We find that the widths, locations, and shapes of two prominent structures, the 2:1 and 3:1 MMRs, could be used to determine the mass, semimajor axis, and eccentricity of the planetary perturber and present an algorithm for doing so. These MMR structures can be used to narrow the position and even determine the planetary properties (such as mass) of any inferred but as-yet-unseen planets within a debris disk. We also briefly discuss the implications of eccentric disks on brightness asymmetries and their dependence on the wavelengths with which these disks are observed.

  9. The orbital eccentricities of binary millisecond pulsars in globular clusters

    Science.gov (United States)

    Rasio, Frederic A.; Heggie, Douglas C.

    1995-01-01

    Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order e(sub i) approximately 10(exp -6) to 10(exp -3). In globular clusters, however, higher eccentricities e(sub f) much greater than e(sub i) can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process is much larger than previously estimated. This is becuse, even for initially circular binaries, the induced eccentricity e(sub f) for an encounter with pericenter separation r(sub p) beyond a few times the binary semimajor axis a declines only as a power law (e(sub f) varies as (r(sub p)/a)(exp -5/2), and not as an exponential. We find that all currently known LMBPs in clusters were probably affected by interactions, with their current eccentricities typically greater than at birth by an order of magnitude or more.

  10. FOREVER ALONE? TESTING SINGLE ECCENTRIC PLANETARY SYSTEMS FOR MULTIPLE COMPANIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G.; Bailey, J.; Salter, G. S.; Wright, D. [Department of Astrophysics, School of Physics, Faculty of Science, The University of New South Wales, Sydney, NSW 2052 (Australia); Wang Songhu; Zhou Jilin [Department of Astronomy and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, Nanjing 210093 (China); Butler, R. P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Jones, H. R. A. [University of Hertfordshire, Centre for Astrophysics Research, Science and Technology Research Institute, College Lane, AL10 9AB Hatfield (United Kingdom); O' Toole, S. J. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Carter, B. D., E-mail: rob@phys.unsw.edu.au [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia)

    2013-09-15

    Determining the orbital eccentricity of an extrasolar planet is critically important for understanding the system's dynamical environment and history. However, eccentricity is often poorly determined or entirely mischaracterized due to poor observational sampling, low signal-to-noise, and/or degeneracies with other planetary signals. Some systems previously thought to contain a single, moderate-eccentricity planet have been shown, after further monitoring, to host two planets on nearly circular orbits. We investigate published apparent single-planet systems to see if the available data can be better fit by two lower-eccentricity planets. We identify nine promising candidate systems and perform detailed dynamical tests to confirm the stability of the potential new multiple-planet systems. Finally, we compare the expected orbits of the single- and double-planet scenarios to better inform future observations of these interesting systems.

  11. Flow of viscoplastic fluids in eccentric annular geometries

    DEFF Research Database (Denmark)

    Szabo, Peter; Hassager, Ole

    1992-01-01

    A classification of flowfields for the flow of a Bingham fluid in general eccentric annular geometries is presented. Simple arguments show that a singularity can exist in the stress gradient on boundaries between zones with yielded and un-yielded fluid respectively. A Finite Element code is used...... to verify this property of the Bingham fluid. An analytical solution for the flowfield in case of small eccentricities is derived....

  12. Concentric or eccentric training: effects and cross-education

    OpenAIRE

    Maquet, Didier; Delvaux, François; Croisier, Jean-Louis

    2009-01-01

    The purpose of this study was to compare pure concentric and eccentric isokinetic training with respect to their possible specificity in the progression of strength of the knee flexor and extensor muscles. Subjects were divided into 2 groups (eccentric or concentric training) and performed a specific training of dominant leg. Before and after the training session, isokinetic performances of trained leg and non-trained leg (cross-education) were evaluated. We observed a greater increase of ...

  13. Exoplanet orbital eccentricity: multiplicity relation and the Solar System.

    Science.gov (United States)

    Limbach, Mary Anne; Turner, Edwin L

    2015-01-06

    The known population of exoplanets exhibits a much wider range of orbital eccentricities than Solar System planets and has a much higher average eccentricity. These facts have been widely interpreted to indicate that the Solar System is an atypical member of the overall population of planetary systems. We report here on a strong anticorrelation of orbital eccentricity with multiplicity (number of planets in the system) among cataloged radial velocity (RV) systems. The mean, median, and rough distribution of eccentricities of Solar System planets fits an extrapolation of this anticorrelation to the eight-planet case rather precisely despite the fact that no more than two Solar System planets would be detectable with RV data comparable to that in the exoplanet sample. Moreover, even if regarded as a single or double planetary system, the Solar System lies in a reasonably heavily populated region of eccentricity-multiplicity space. Thus, the Solar System is not anomalous among known exoplanetary systems with respect to eccentricities when its multiplicity is taken into account. Specifically, as the multiplicity of a system increases, the eccentricity decreases roughly as a power law of index -1.20. A simple and plausible but ad hoc and model-dependent interpretation of this relationship implies that ∼ 80% of the one-planet and 25% of the two-planet systems in our sample have additional, as yet undiscovered, members but that systems of higher observed multiplicity are largely complete (i.e., relatively rarely contain additional undiscovered planets). If low eccentricities indeed favor high multiplicities, habitability may be more common in systems with a larger number of planets.

  14. Eccentric or Concentric Exercises for the Treatment of Tendinopathies?

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, René B; Silbernagel, Karin Grävare

    2015-01-01

    with respect to parameters like load magnitude, speed of movement, and recovery period between exercise sessions. Future studies should control for these loading parameters, evaluate various exercise dosages, and also think beyond isolated eccentric exercises to arrive at firm recommendations regarding...... evidence that demonstrate that isolated eccentric loading exercises improve the clinical outcome more than other loading therapies. However, the great variation and sometimes insufficient reporting of details of treatment protocols hamper the interpretation of what may be the optimal exercise regime...

  15. Chronic Adaptations to Eccentric Training: A Systematic Review.

    Science.gov (United States)

    Douglas, Jamie; Pearson, Simon; Ross, Angus; McGuigan, Mike

    2017-05-01

    Resistance training is an integral component of physical preparation for athletes. A growing body of evidence indicates that eccentric strength training methods induce novel stimuli for neuromuscular adaptations. The purpose of this systematic review was to determine the effects of eccentric training in comparison to concentric-only or traditional (i.e. constrained by concentric strength) resistance training. Searches were performed using the electronic databases MEDLINE via EBSCO, PubMed and SPORTDiscus via EBSCO. Full journal articles investigating the long-term (≥4 weeks) effects of eccentric training in healthy (absence of injury or illness during the 4 weeks preceding the training intervention), adult (17-35 years), human participants were selected for the systematic review. A total of 40 studies conformed to these criteria. Eccentric training elicits greater improvements in muscle strength, although in a largely mode-specific manner. Superior enhancements in power and stretch-shortening cycle (SSC) function have also been reported. Eccentric training is at least as effective as other modalities in increasing muscle cross-sectional area (CSA), while the pattern of hypertrophy appears nuanced and increased CSA may occur longitudinally within muscle (i.e. the addition of sarcomeres in series). There appears to be a preferential increase in the size of type II muscle fibres and the potential to exert a unique effect upon fibre type transitions. Qualitative and quantitative changes in tendon tissue that may be related to the magnitude of strain imposed have also been reported with eccentric training. Eccentric training is a potent stimulus for enhancements in muscle mechanical function, and muscle-tendon unit (MTU) morphological and architectural adaptations. The inclusion of eccentric loads not constrained by concentric strength appears to be superior to traditional resistance training in improving variables associated with strength, power and speed

  16. Acute Effects of Eccentric Overload on Concentric Front Squat Performance.

    Science.gov (United States)

    Munger, Cameron N; Archer, David C; Leyva, Whitney D; Wong, Megan A; Coburn, Jared W; Costa, Pablo B; Brown, Lee E

    2017-05-01

    Munger, CN, Archer, DC, Leyva, WD, Wong, MA, Coburn, JW, Costa, PB, and Brown, LE. Acute effects of eccentric overload on concentric front squat performance. J Strength Cond Res 31(5): 1192-1197, 2017-Eccentric overload is used to enhance performance. The purpose of this study was to investigate the acute effects of eccentric overload on concentric front squat performance. Twenty resistance-trained men (age = 23.80 ± 1.82 years, height = 176.95 ± 5.21 cm, mass = 83.49 ± 10.43 kg, 1 repetition maximum [1RM] front squat = 131.02 ± 21.32 kg) volunteered. A dynamic warm-up and warm-up sets of front squat were performed. Eccentric hooks were added to the barbell. They descended for 3 seconds, until eccentric hooks released, and performed the concentric phase as fast as possible. There were 3 randomly ordered conditions with the concentric phase always at 90% 1RM and the eccentric phase at 105, 110, and 120% of 1RM. Two repetitions were performed for each condition. A repeated measures analysis of variance was used to determine differences. For peak velocity, there were main effects for time and condition (p front squat is a precursor.

  17. Exoplanet orbital eccentricities derived from LAMOST-Kepler analysis.

    Science.gov (United States)

    Xie, Ji-Wei; Dong, Subo; Zhu, Zhaohuan; Huber, Daniel; Zheng, Zheng; De Cat, Peter; Fu, Jianning; Liu, Hui-Gen; Luo, Ali; Wu, Yue; Zhang, Haotong; Zhang, Hui; Zhou, Ji-Lin; Cao, Zihuang; Hou, Yonghui; Wang, Yuefei; Zhang, Yong

    2016-10-11

    The nearly circular (mean eccentricity [Formula: see text]) and coplanar (mean mutual inclination [Formula: see text]) orbits of the solar system planets motivated Kant and Laplace to hypothesize that planets are formed in disks, which has developed into the widely accepted theory of planet formation. The first several hundred extrasolar planets (mostly Jovian) discovered using the radial velocity (RV) technique are commonly on eccentric orbits ([Formula: see text]). This raises a fundamental question: Are the solar system and its formation special? The Kepler mission has found thousands of transiting planets dominated by sub-Neptunes, but most of their orbital eccentricities remain unknown. By using the precise spectroscopic host star parameters from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) observations, we measure the eccentricity distributions for a large (698) and homogeneous Kepler planet sample with transit duration statistics. Nearly half of the planets are in systems with single transiting planets (singles), whereas the other half are multiple transiting planets (multiples). We find an eccentricity dichotomy: on average, Kepler singles are on eccentric orbits with [Formula: see text] 0.3, whereas the multiples are on nearly circular [Formula: see text] and coplanar [Formula: see text] degree) orbits similar to those of the solar system planets. Our results are consistent with previous studies of smaller samples and individual systems. We also show that Kepler multiples and solar system objects follow a common relation [[Formula: see text](1-2)[Formula: see text

  18. Eccentric strength and endurance in patients with unilateral intermittent claudication

    Directory of Open Access Journals (Sweden)

    Márcio Basyches

    2009-04-01

    Full Text Available OBJECTIVE: To analyze concentric and eccentric strength and endurance in patients with unilateral intermittent claudication. INTRODUCTION: Basic motor tasks are composed of concentric, isometric, and eccentric actions, which are related and contribute to physical performance. In previous studies of patients with intermittent claudication, the disease-related reduction in concentric and isometric muscular strength and endurance resulted in poorer walking performance. To date, no study has evaluated eccentric muscle action in patients with intermittent claudication. METHODS: Eleven patients with unilateral intermittent claudication performed isokinetic concentric and eccentric actions at the ankle joints to assess peak torque and total work in both symptomatic and asymptomatic legs. RESULTS: Concentric peak torque and total work were lower in the symptomatic than in the asymptomatic leg (80 ± 32 vs. 95 ± 41 N/m, P = 0.01; 1479 ± 667 vs. 1709 ± 879 J, P = 0.03, respectively. There were no differences in eccentric peak torque and total work between symptomatic and asymptomatic legs (96 ± 30 vs. 108 ± 48 N/m; 1852 ± 879 vs. 1891 ± 755 J, respectively. CONCLUSION: Strength and endurance in the symptomatic leg were lower during concentric compared to eccentric action. Future studies are recommended to investigate the mechanisms underlying these responses and to analyze the effects of interventions to improve concentric strength and endurance on functional limitations in patients with intermittent claudication.

  19. Frozen orbits at high eccentricity and inclination: application to Mercury orbiter

    Science.gov (United States)

    Delsate, N.; Robutel, P.; Lemaître, A.; Carletti, T.

    2010-11-01

    We hereby study the stability of a massless probe orbiting around an oblate central body (planet or planetary satellite) perturbed by a third body, assumed to lay in the equatorial plane (Sun or Jupiter for example) using a Hamiltonian formalism. We are able to determine, in the parameters space, the location of the frozen orbits, namely orbits whose orbital elements remain constant on average, to characterize their stability/unstability and to compute the periods of the equilibria. The proposed theory is general enough, to be applied to a wide range of probes around planet or natural planetary satellites. The BepiColombo mission is used to motivate our analysis and to provide specific numerical data to check our analytical results. Finally, we also bring to the light that the coefficient J 2 is able to protect against the increasing of the eccentricity due to the Kozai-Lidov effect and the coefficient J 3 determines a shift of the equilibria.

  20. Taking into Account Planetary Perturbations in Lunar Theory

    Science.gov (United States)

    Ivanova, T. V.

    This paper is devoted to constructing the semi-analytical theory of the Moon motion in the trigonometric form within the framework of the general planetary theory GPT (V. A. Brumberg, Analytical Techniques of Celestial Mechanics, Springer, Heidelberg, 1995). The determination of planetary perturbations in Lunar theory is one of the most urgent problem of celestial mechanics. Usually the construction of Lunar theory is divided into two steps. The first one is to solve the main problem. The planetary perturbations are calculated separately on the second step. In this paper the Moon is considered as an additional planet in the field of eight major planets (Pluto being excluded). Therefore here there are not any division into the main and the planetary parts. This allows to take into account both solar and planetary perturbations with the same precision. As a rule a solution of the main problem may be represented in the purely trigonometric form treating the longitudes of the lunar perigee and node as trigonometric arguments. But this form is violated when taking into account the planetary perturbations provided by the classical theories of the major planets. The GPT is capable to represente the coordinates of the major planets by means of the power series in eccentric and oblique variables with trigonometric coefficients in mean longitudes of the planets. The behaviour of the evolutionary eccentric and oblique variables is governed by an autonomous secular system which may be solved in the trigonometric form. The aim of this paper is to present the Lunar theory in the same form. As an initial approximation a quasi-periodic intermediary generalizing the Hill's variational curve is built. This orbit includes all solar and planetary inequalities independent of eccentricities and inclinations of all bodies. The solution corresponding to this intermediary is represented by the multiple Fourier series depending on the mean longitudes of the bodies under consideration. The

  1. Exoplanet orbital eccentricity: Multiplicity relation and the Solar System

    Science.gov (United States)

    Limbach, Mary Anne; Turner, Edwin L.

    2015-01-01

    The known population of exoplanets exhibits a much wider range of orbital eccentricities than Solar System planets and has a much higher average eccentricity. These facts have been widely interpreted to indicate that the Solar System is an atypical member of the overall population of planetary systems. We report here on a strong anticorrelation of orbital eccentricity with multiplicity (number of planets in the system) among cataloged radial velocity (RV) systems. The mean, median, and rough distribution of eccentricities of Solar System planets fits an extrapolation of this anticorrelation to the eight-planet case rather precisely despite the fact that no more than two Solar System planets would be detectable with RV data comparable to that in the exoplanet sample. Moreover, even if regarded as a single or double planetary system, the Solar System lies in a reasonably heavily populated region of eccentricity−multiplicity space. Thus, the Solar System is not anomalous among known exoplanetary systems with respect to eccentricities when its multiplicity is taken into account. Specifically, as the multiplicity of a system increases, the eccentricity decreases roughly as a power law of index –1.20. A simple and plausible but ad hoc and model-dependent interpretation of this relationship implies that ∼80% of the one-planet and 25% of the two-planet systems in our sample have additional, as yet undiscovered, members but that systems of higher observed multiplicity are largely complete (i.e., relatively rarely contain additional undiscovered planets). If low eccentricities indeed favor high multiplicities, habitability may be more common in systems with a larger number of planets. PMID:25512527

  2. Conformal invariance of curvature perturbation

    CERN Document Server

    Gong, Jinn-Ouk; Park, Wan Il; Sasaki, Misao; Song, Yong-Seon

    2011-01-01

    We show that in the single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special time slicing, the uniform-conformal transformation slicing, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the delta N formalism, and show its conformal invariance.

  3. Conformal invariance of curvature perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jinn-Ouk [Theory Division, CERN, CH-1211 Genève 23 (Switzerland); Hwang, Jai-chan [Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Park, Wan Il; Sasaki, Misao; Song, Yong-Seon, E-mail: jinn-ouk.gong@cern.ch, E-mail: jchan@knu.ac.kr, E-mail: wipark@kias.re.kr, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: ysong@kias.re.kr [Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)

    2011-09-01

    We show that in the single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special time slicing, the uniform-conformal transformation slicing, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the δN formalism, and show its conformal invariance.

  4. Transiting planets - light-curve analysis for eccentric orbits

    Science.gov (United States)

    Kipping, David M.

    2008-09-01

    Transiting planet light curves have historically been used predominantly for measuring the depth and hence ratio of the planet-star radii, p. Equations have previously been presented by Seager & Mallén-Ornelas for the analysis of the total and trough transit light-curve time to derive the ratio of semimajor axis to stellar radius, a/R*, in the case of circular orbits. Here, a new analytic model is proposed which operates for the more general case of an eccentric orbit. We aim to investigate three major effects our model predicts: (i) the degeneracy in transit light-curve solutions for eccentricity, e > 0; (ii) the asymmetry of the light curve and the resulting shift in the mid-transit time, TMID; (iii) the effect of eccentricity on the ingress and egress slopes. It is also shown that a system with changing eccentricity and inclination may produce a long-term transit time variation (LTTV). Furthermore, we use our model in a re-analysis of HD209458b archived data by Richardson et al., where we include the confirmed non-zero eccentricity and derive a 24-μm planetary radius of RP = 1.275RJ +/- 0.082RJ (where RJ = 1 Jovian radius), which is ~1 per cent larger than if we assume a circular orbit.

  5. Effects of age and eccentricity on visual target detection

    Directory of Open Access Journals (Sweden)

    Nicole eGruber

    2014-01-01

    Full Text Available The aim of this study was to examine the effects of aging and target eccentricity on a visual search task comprising 30 images of everyday life projected into a hemisphere, realizing a ± 90° visual field. The task performed binocularly allowed participants to freely move their eyes to scan images for an appearing target or distractor stimulus (presented at 10°; 30°, and 50° eccentricity. The distractor stimulus required no response, while the target stimulus required acknowledgment by pressing the response button. 117 healthy subjects (mean age=49.63 years, SD=17.40 years, age range 20-78 years were studied. The results show that target detection performance decreases with age as well as with increasing eccentricity, especially for older subjects. Reaction time also increases with age and eccentricity, but in contrast to target detection, there is no interaction between age and eccentricity. Eye movement analysis showed that younger subjects exhibited a passive search strategy while older subjects exhibited an active search strategy probably as a compensation for their reduced peripheral detection performance.

  6. Inclination evolution of protoplanetary discs around eccentric binaries

    Science.gov (United States)

    Zanazzi, J. J.; Lai, Dong

    2018-01-01

    It is usually thought that viscous torque works to align a circumbinary disc with the binary's orbital plane. However, recent numerical simulations suggest that the disc may evolve to a configuration perpendicular to the binary orbit ('polar alignment) if the binary is eccentric and the initial disc-binary inclination is sufficiently large. We carry out a theoretical study on the long-term evolution of inclined discs around eccentric binaries, calculating the disc warp profile and dissipative torque acting on the disc. For discs with aspect ratio H/r larger than the viscosity parameter α, bending wave propagation effectively makes the disc precess as a quasi-rigid body, while viscosity acts on the disc warp and twist to drive secular evolution of the disc-binary inclination. We derive a simple analytic criterion (in terms of the binary eccentricity and initial disc orientation) for the disc to evolve towards polar alignment with the eccentric binary. When the disc has a non-negligible angular momentum compared to the binary, the final 'polar alignment' inclination angle is reduced from 90°. For typical protoplanetary disc parameters, the time-scale of the inclination evolution is shorter than the disc lifetime, suggesting that highly inclined discs and planets may exist orbiting eccentric binaries.

  7. The Role of Visual Eccentricity on Preference for Abstract Symmetry.

    Science.gov (United States)

    Rampone, Giulia; O' Sullivan, Noreen; Bertamini, Marco

    2016-01-01

    This study tested preference for abstract patterns, comparing random patterns to a two-fold bilateral symmetry. Stimuli were presented at random locations in the periphery. Preference for bilateral symmetry has been extensively studied in central vision, but evaluation at different locations had not been systematically investigated. Patterns were presented for 200 ms within a large circular region. On each trial participant changed fixation and were instructed to select any location. Eccentricity values were calculated a posteriori as the distance between ocular coordinates at pattern onset and coordinates for the centre of the pattern. Experiment 1 consisted of two Tasks. In Task 1, participants detected pattern regularity as fast as possible. In Task 2 they evaluated their liking for the pattern on a Likert-scale. Results from Task 1 revealed that with our parameters eccentricity did not affect symmetry detection. However, in Task 2, eccentricity predicted more negative evaluation of symmetry, but not random patterns. In Experiment 2 participants were either presented with symmetry or random patterns. Regularity was task-irrelevant in this task. Participants discriminated the proportion of black/white dots within the pattern and then evaluated their liking for the pattern. Even when only one type of regularity was presented and regularity was task-irrelevant, preference evaluation for symmetry decreased with increasing eccentricity, whereas eccentricity did not affect the evaluation of random patterns. We conclude that symmetry appreciation is higher for foveal presentation in a way not fully accounted for by sensitivity.

  8. Cosmological perturbations in antigravity

    Science.gov (United States)

    Oltean, Marius; Brandenberger, Robert

    2014-10-01

    We compute the evolution of cosmological perturbations in a recently proposed Weyl-symmetric theory of two scalar fields with oppositely signed conformal couplings to Einstein gravity. It is motivated from the minimal conformal extension of the standard model, such that one of these scalar fields is the Higgs while the other is a new particle, the dilaton, introduced to make the Higgs mass conformally symmetric. At the background level, the theory admits novel geodesically complete cyclic cosmological solutions characterized by a brief period of repulsive gravity, or "antigravity," during each successive transition from a big crunch to a big bang. For simplicity, we consider scalar perturbations in the absence of anisotropies, with potential set to zero and without any radiation. We show that despite the necessarily wrong-signed kinetic term of the dilaton in the full action, these perturbations are neither ghostlike nor tachyonic in the limit of strongly repulsive gravity. On this basis, we argue—pending a future analysis of vector and tensor perturbations—that, with respect to perturbative stability, the cosmological solutions of this theory are viable.

  9. Perturbed S3 neutrinos

    DEFF Research Database (Denmark)

    jora, Renata; Schechter, Joseph; Naeem Shahid, M.

    2009-01-01

    We study the effects of the perturbation which violates the permutation symmetry of three Majorana neutrinos but preserves the well known (23) interchange symmetry. This is done in the presenceof an arbitrary Majorana phase which serves to insure the degeneracy of the three neutrinos...

  10. Selective serotonin reuptake inhibitors and rhabdomyolysis after eccentric exercise.

    Science.gov (United States)

    Labotz, Michele; Wolff, Toby K; Nakasone, Kenneth T; Kimura, Iris F; Hetzler, Ronald K; Nichols, Andrew W

    2006-09-01

    The purpose of this report was to review three cases of clinically significant rhabdomyolysis that developed in research subjects after completing an eccentric exercise protocol. All three cases occurred in subjects who reported use of selective serotonin reuptake inhibitors (SSRI). Sixty-three subjects enrolled in the study. Subjects performed 15 sets of 15 repetitions of maximal eccentric contractions of the elbow flexors. Subjects were then monitored on a daily basis for development of delayed onset muscle soreness (DOMS). Subjects received either microcurrent electrical neuromuscular stimulation (MENS) or sham treatment. Three subjects developed clinically significant rhabdomyolysis after performing this exercise protocol. Affected subjects were the only subjects who reported use of SSRI during the study period. This report raises suspicion of SSRI use as a predisposing factor to muscle injury after eccentric exercise.

  11. Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

    Directory of Open Access Journals (Sweden)

    Kamanli Mehmet

    2017-01-01

    Full Text Available After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

  12. Involvement of eccentric muscle actions in giant slalom racing.

    Science.gov (United States)

    Berg, H E; Eiken, O; Tesch, P A

    1995-12-01

    Joint angular movements and muscle activation (EMG), were determined in male elite racers while performing the giant slalom. Movement cycles averaged 3.5 +/- 0.6 s (left plus right turn), and knee angle ranged 66-114 degrees (180 degrees = straight leg). Knee extensor muscle use was dominated (rectified EMG; P ski during the turn. Time spent while decreasing knee angle (eccentric muscle action) of outside leg averaged 1.0 +/- 0.2 s. This phase was longer (P slalom skiing is dominated by slow eccentric muscle actions performed at near maximum voluntary force. Because of their greater ability to generate force, eccentric muscle actions may be warranted or even required to resist the G-forces induced during the turn phase.

  13. The highly eccentric detached eclipsing binaries in ACVS and MACC

    Science.gov (United States)

    Shivvers, Isaac; Bloom, Joshua S.; Richards, Joseph W.

    2014-06-01

    Next-generation synoptic photometric surveys will yield unprecedented (for the astronomical community) volumes of data and the processes of discovery and rare-object identification are, by necessity, becoming more autonomous. Such autonomous searches can be used to find objects of interest applicable to a wide range of outstanding problems in astronomy, and in this paper we present the methods and results of a largely autonomous search for highly eccentric detached eclipsing binary systems in the Machine-learned All-Sky Automated Survey Classification Catalog. 106 detached eclipsing binaries with eccentricities of e ≳ 0.1 are presented, most of which are identified here for the first time. We also present new radial-velocity curves and absolute parameters for six of those systems with the long-term goal of increasing the number of highly eccentric systems with orbital solutions, thereby facilitating further studies of the tidal circularization process in binary stars.

  14. Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

    Science.gov (United States)

    Kamanli, Mehmet; Unal, Alptug

    2017-10-01

    After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

  15. Eccentric exercise training: modalities, applications and perspectives.

    Science.gov (United States)

    Isner-Horobeti, Marie-Eve; Dufour, Stéphane Pascal; Vautravers, Philippe; Geny, Bernard; Coudeyre, Emmanuel; Richard, Ruddy

    2013-06-01

    Eccentric (ECC) exercise is classically used to improve muscle strength and power in healthy subjects and athletes. Due to its specific physiological and mechanical properties, there is an increasing interest in employing ECC muscle work for rehabilitation and clinical purposes. Nowadays, ECC muscle actions can be generated using various exercise modalities that target small or large muscle masses with minimal or no muscle damage or pain. The most interesting feature of ECC muscle actions is to combine high muscle force with a low energy cost (typically 4- to 5-times lower than concentric muscle work) when measured during leg cycle ergometry at a similar mechanical power output. Therefore, if caution is taken to minimize the occurrence of muscle damage, ECC muscle exercise can be proposed not only to athletes and healthy subjects, but also to individuals with moderately to severely limited exercise capacity, with the ultimate goal being to improve their functional capacity and quality of life. The first part of this review article describes the available exercise modalities to generate ECC muscle work, including strength and conditioning exercises using the body's weight and/or additional external loads, classical isotonic or isokinetic exercises and, in addition, the oldest and newest specifically designed ECC ergometers. The second part highlights the physiological and mechanical properties of ECC muscle actions, such as the well-known higher muscle force-generating capacity and also the often overlooked specific cardiovascular and metabolic responses. This point is particularly emphasized by comparing ECC and concentric muscle work performed at similar mechanical (i.e., cycling mechanical power) or metabolic power (i.e., oxygen uptake, VO2). In particular, at a similar mechanical power, ECC muscle work induces lower metabolic and cardiovascular responses than concentric muscle work. However, when both exercise modes are performed at a similar level of VO2, a

  16. The eccentric-distance sum of some graphs

    Directory of Open Access Journals (Sweden)

    Padmapriya P

    2017-04-01

    Full Text Available Let $G = (V,E$ be a simple connected graph. Theeccentric-distance sum of $G$ is defined as$\\xi^{ds}(G =\\ds\\sum_{\\{u,v\\}\\subseteq V(G} [e(u+e(v] d(u,v$, where $e(u$ %\\dsis the eccentricity of the vertex $u$ in $G$ and $d(u,v$ is thedistance between $u$ and $v$. In this paper, we establish formulaeto calculate the eccentric-distance sum for some graphs, namelywheel, star, broom, lollipop, double star, friendship, multi-stargraph and the join of $P_{n-2}$ and $P_2$.

  17. Transmission line resonance technique for eccentric core optical fibers

    Science.gov (United States)

    Georgantzos, E.; Boucouvalas, A. C.

    2016-12-01

    In several cases optical fibers in telecommunications have cores of non circular geometry. Fibre optic deformations appear in optical fibres for many reasons. Optical fibre core ellipticity for example where the fibre optic core is not perfectly circular due to fibre optic manufacturing tolerances, is measured and often is a problem. Optical fibre core eccentricity, where the fibre core is not on the axis of the fibre, but it is offset by a small length. This is another issue and very important for ensuring performance low loss splices and connector losses. Both of ellipticity and eccentricity are specified in accordance to international standards for fibre optic manufacturing telecommunications grade fibres. The present paper studies ellipticity and core eccentricity specifically and presents a new method for analysing their effect. We present an extension of the transmission line technique as a means of studying such fibers and deriving necessary parameters. Conformal mapping on the other hand is a simple mathematical tool by which we can generate sets of orthogonal two-dimensional coordinate systems. Shortly a conformal map of Cartesian two-dimensional space is defined by any analytical function W(z) where z, w, are: z = x + jy, W = θ + j φ The function deriving by the conformal mapping transformation h(θ ,φ )=| ∂w/∂z | = 1/|∂z/∂w|, can be used in order to define ∇A → and ∇×A → where A → is the magnetic or electric field in the derived orthogonal coordinate system. Useful conformal maps for fiber optics applications should have the property that the equation θ(x, y) = constant, is forming closed curves in a Cartesian two-dimensional space (x,y). If θ(x, y) = constant represents a set of co-eccentric circles, we obtain the normal case of conventional fibers with circular cores. If θ(x, y) = constant represents a set of eclipses, we are have the formation of elliptic core optical fibers. If θ(x, y) = constant represents a set of

  18. THE ROLE AND IMPLEMENTATION OF ECCENTRIC TRAINING IN ATHLETIC REHABILITATION: TENDINOPATHY, HAMSTRING STRAINS, AND ACL RECONSTRUCTION

    Science.gov (United States)

    Reiman, Michael

    2011-01-01

    The benefits and proposed physiological mechanisms of eccentric exercise have previously been elucidated and eccentric exercise has been used for well over seventy years. Traditionally, eccentric exercise has been used as a regular component of strength training. However, in recent years, eccentric exercise has been used in rehabilitation to manage a host of conditions. Of note, there is evidence in the literature supporting eccentric exercise for the rehabilitation of tendinopathies, muscle strains, and in anterior cruciate ligament (ACL) rehabilitation. The purpose of this Clinical Commentary is to discuss the physiologic mechanism of eccentric exercise as well as to review the literature regarding the utilization of eccentric training during rehabilitation. A secondary purpose of this commentary is to provide the reader with a framework for the implementation of eccentric training during rehabilitation of tendinopathies, muscle strains, and after ACL reconstruction. PMID:21655455

  19. Perturbations in warm inflation

    Energy Technology Data Exchange (ETDEWEB)

    de Oliveira, H. P.; Joras, S. E.

    2001-09-15

    Warm inflation is an interesting possibility to describe the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here we analyze the dynamics of warm inflation generalizing the usual slow-roll parameters that are useful for characterizing the inflationary phase. We study the evolution of entropy and adiabatic perturbations, where the main result is that for a very small amount of dissipation the entropy perturbations can be neglected and the purely adiabatic perturbations will be responsible for the primordial spectrum of inhomogeneities. Taking into account the Cosmic Background Explorer Differential Microwave Radiometer data of the cosmic microwave background anisotropy as well as the fact that the interval of inflation for which the scales of astrophysical interest cross outside the Hubble radius is about 50 e-folds before the end of inflation, we could estimate the magnitude of the dissipation term. It is also possible to show that at the end of inflation the universe is hot enough to provide a smooth transition to the radiation era.

  20. Detection of Static Eccentricity Fault in Saturated Induction Motors by ...

    African Journals Online (AJOL)

    Unfortunately, motor current signature analysis (MCSA) cannot detect the small degrees of the purely static eccentricity (SE) defects, while the air-gap magnetic flux signature analysis (FSA) is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE) method. In order to show the ...

  1. Systemic cytokine response to three bouts of eccentric exercise

    Directory of Open Access Journals (Sweden)

    Stephen M. Cornish

    2014-01-01

    Full Text Available This research examined the changes in inflammatory cytokines interleukin 6 (IL-6, IL-1β, IL-10, as well as muscle force, muscle soreness, thigh circumference, and range of motion in response to 3 bouts of eccentric knee extension. Ten males were recruited to participate. The participants performed eccentric exercise on 3 consecutive days on the knee extensors on the right leg separated by 24 h. Participants performed 6 sets of 10 repetitions of isokinetic eccentric knee extension at 120° per second. Blood was sampled before and after each exercise bout and 24 h after the final exercise bout. Muscle isometric force, delayed onset muscle soreness (DOMS, thigh circumference, and range of motion were evaluated before and after each exercise bout and 24 h after the final exercise bout. There were no statistically significant differences noted for the changes in isometric strength, thigh circumference, and range of motion, or IL-6 over the 4 days (all p > 0.05. On the second day and third day there was a significant increase noted in DOMS as compared with baseline (p < 0.05. These results suggest that 3 consecutive days of eccentric exercise results in DOMS but does not produce a sustained systemic inflammatory reaction or changes in muscle function.

  2. Corneal eccentricity as a tool for the diagnosis of keratoconus

    NARCIS (Netherlands)

    Dao, C. L.; Kok, J. H.; Brinkman, C. J.; van Mil, C. J.

    1994-01-01

    Ninety-nine eyes with keratoconus of 64 patients were examined using the sagittal radii method to determine the corneal flattening and compared with 100 eyes of 50 healthy controls. To express the degree of this flattening, four numerical eccentricity (E) values for each eye were calculated. The

  3. Effects of concentric vs eccentric loading on cardiovascular ...

    African Journals Online (AJOL)

    So, the present study was aimed at bridging this gap. This is the first study to compare the metabolic effects of eccentric and concentric resistance exercise at sub maximal workload (75% of the 10-Repetition maximum) previously shown to produce skeletal muscle hypertrophy and to augment strength during chronic training ...

  4. A massive millisecond pulsar in an eccentric binary

    Science.gov (United States)

    Barr, E. D.; Freire, P. C. C.; Kramer, M.; Champion, D. J.; Berezina, M.; Bassa, C. G.; Lyne, A. G.; Stappers, B. W.

    2017-02-01

    The recent discovery of a population of eccentric (e ˜ 0.1) millisecond pulsar (MSP) binaries with low-mass white dwarf companions in the Galactic field represents a challenge to evolutionary models that explain MSP formation as recycling: All such models predict that the orbits become highly circularized during a long period of accretion. The members of this new population exhibit remarkably similar properties (orbital periods, eccentricities, companion masses, spin periods), and several models have been put forward that suggest a common formation channel. In this work, we present the results of an extensive timing campaign focusing on one member of this new population, PSR J1946+3417. Through the measurement of both the advance of periastron and the Shapiro delay for this system, we determine the mass of the pulsar, mass of the companion and the inclination of the orbit to be 1.828(22) M⊙, 0.2656(19) M⊙ and 76.4 ± 0.6 degrees, respectively, under the assumption that general relativity is the true description of gravity. Notably, this is the third highest mass measured for any pulsar. Using these masses and the astrometric properties of PSR J1946+3417, we examine three proposed formation channels for eccentric MSP binaries. While our results are consistent with circumbinary disc-driven eccentricity growth or neutron star to strange star phase transition, we rule out rotationally delayed accretion-induced collapse as the mechanism responsible for the configuration of the PSR J1946+3417 system.

  5. Eccentric-fluted beam pipes to damp quadrupole higher-order modes

    Directory of Open Access Journals (Sweden)

    M. Sawamura

    2010-02-01

    Full Text Available An eccentric-fluted beam pipe is proposed to damp quadrupole modes in a cavity. The eccentric flutes act as a mode converter from quadrupole to dipole. Optimizing the parameters of the eccentric-fluted beam pipe allows sufficient damping of both degenerate quadrupole modes. The external Q values of the eccentric-fluted beam pipe measured with a low power model cavity agree well with those calculated with the 3D electromagnetic field simulation code MAFIA.

  6. Eccentric-fluted beam pipes to damp quadrupole higher-order modes

    Science.gov (United States)

    Sawamura, M.; Furuya, T.; Sakai, H.; Takahashi, T.; Umemori, K.; Shinoe, K.

    2010-02-01

    An eccentric-fluted beam pipe is proposed to damp quadrupole modes in a cavity. The eccentric flutes act as a mode converter from quadrupole to dipole. Optimizing the parameters of the eccentric-fluted beam pipe allows sufficient damping of both degenerate quadrupole modes. The external Q values of the eccentric-fluted beam pipe measured with a low power model cavity agree well with those calculated with the 3D electromagnetic field simulation code MAFIA.

  7. Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Filip, Peter; Lednicky, Richard; Masui, Hiroshi; Xu, Nu

    2010-07-07

    Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.

  8. Achilles tendon of wistar rats treated with laser therapy and eccentric exercise

    OpenAIRE

    Souza, Maria Verônica de; Silva, Carlos Henrique Osório; Silva, Micheline Ozana da; Costa, Marcela Bueno Martins da; Dornas, Raul Felipe; Borges, Andréa Pacheco Batista; Natali, Antônio José

    2015-01-01

    ABSTRACTIntroduction:Both laser therapy and eccentric exercises are used in tendon injuries. However, the association of these physiotherapeutic modalities is yet little investigated.Objective:To evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking) on Achilles tendinopathy of Wistar rats.Method:Eighteen Achilles tendon from 15 adult male Wistar rats were used. Tendons were distributed in six groups (laser, eccentric exercise, laser and eccentric e...

  9. Ischemic Preconditioning Blunts Muscle Damage Responses Induced by Eccentric Exercise.

    Science.gov (United States)

    Franz, Alexander; Behringer, Michael; Harmsen, Jan-Frieder; Mayer, Constantin; Krauspe, Rüdiger; Zilkens, Christoph; Schumann, Moritz

    2017-08-22

    Ischemic preconditioning (IPC) is known to reduce muscle damage induced by ischemia and reperfusion-injury (I/R-Injury) during surgery. Due to similarities between the pathophysiological formation of I/R-injury and eccentric exercise-induced muscle damage (EIMD), as characterized by an intracellular accumulation of Ca, an increased production of reactive oxygen species and increased pro-inflammatory signaling, the purpose of the present study was to investigate whether IPC performed prior to eccentric exercise may also protect against EIMD. Nineteen healthy men were matched to an eccentric only (ECC) (n=9) or eccentric proceeded by IPC group (IPC+ECC) (n=10). The exercise protocol consisted of bilateral biceps curls (3x10 repetitions at 80% of the concentric 1RM). In IPC+ECC, IPC was applied bilaterally at the upper arms by a tourniquet (200 mmHg) immediately prior to the exercise (3x5 minutes of occlusion, separated by 5 minutes of reperfusion). Creatine Kinase (CK), arm circumference, subjective pain (VAS score) and radial displacement (Tensiomyography, Dm) were assessed before IPC, pre-exercise, post-exercise, 20 minutes-, 2 hours-, 24 hours-, 48 hours- and 72 hours post-exercise. CK differed from baseline only in ECC at 48h (pIPC+ECC (between groups: 24h: p=0.004, 48h: pIPC+ECC (between groups: all pIPC+ECC (between-groups pIPC performed prior to a bout of eccentric exercise of the elbow flexors blunts EIMD and exercise-induced pain, while maintaining the contractile properties of the muscle.

  10. Approximation and perturbation methods

    CERN Document Server

    Iyer, B R

    1993-01-01

    Few problems in nature are amenable to an exact solution and hence when one proceeds from elegant problems of theory to messy complicated problems of practice one is forced to recourse to methods of approximation and perturbation. The development of such techniques has been natural in attempts to extract physically verifiable consequences from either exact solutions of general relativity or from specific astrophysical systems for which an exact solution is impossible to find. However, this should not be taken to imply giving up of mathematical rigour and an appeal to only physical intuition.

  11. Perturbative quantum chromodynamics

    CERN Document Server

    1989-01-01

    This book will be of great interest to advanced students and researchers in the area of high energy theoretical physics. Being the most complete and updated review volume on Perturbative QCD, it serves as an extremely useful textbook or reference book. Some of the reviews in this volume are the best that have been written on the subject anywhere. Contents: Factorization of Hard Processes in QCD (J C Collins, D E Soper & G Sterman); Exclusive Processes in Quantum Chromodynamics (S J Brodsky & G P Lepage); Coherence and Physics of QCD Jets (Yu L Dokshitzer, V A Khoze & S I Troyan); Pomeron in Qu

  12. Effects of Velocity on Electromyographic, Mechanomyographic, and Torque Responses to Repeated Eccentric Muscle Actions.

    Science.gov (United States)

    Hill, Ethan C; Housh, Terry J; Camic, Clayton L; Smith, Cory M; Cochrane, Kristen C; Jenkins, Nathaniel D M; Cramer, Joel T; Schmidt, Richard J; Johnson, Glen O

    2016-06-01

    The purposes of this study were to examine the effects of the velocity of repeated eccentric muscle actions on the torque and neuromuscular responses during maximal isometric and eccentric muscle actions. Twelve resistance-trained men performed 30 repeated, maximal, eccentric, isokinetic muscle actions at randomly ordered velocities of 60, 120, or 180°·s on separate days. Maximal voluntary isometric contractions (MVICs) were performed before (pretest) and after (posttest) the repeated eccentric muscle actions on each day. Eccentric isokinetic peak torque (EIPT) values were the averages of the first 3 and last 3 repetitions of the 30 repeated eccentric muscle actions. During the EIPT and MVIC muscle actions, electromyographic (EMG) and mechanomyographic (MMG) amplitude (EMG AMP and MMG AMP) and mean power frequency (EMG MPF and MMG MPF) values were assessed. These results indicated that the repeated eccentric muscle actions had no effects on EIPT, or the EMG AMP, EMG MPF, or MMG MPF values assessed during the EIPT muscle actions, but decreased MMG AMP. The repeated eccentric muscle actions, however, decreased MVIC torque, and also the EMG AMP and MMG MPF values assessed during the MVIC muscle actions, but increased MMG AMP. The results indicated that the velocity of the repeated eccentric muscle actions affected the MVIC torque responses, but not EIPT or any of the neuromuscular parameters. Furthermore, there are differences in the torque and neuromuscular responses for isometric vs. eccentric muscle actions after repeated eccentric muscle actions.

  13. ELECTROMAGNETIC VIBRATION DISTURBING FORCES AT THE ECCENTRICITY OF ROTOR OF TURBOGENERATOR

    Directory of Open Access Journals (Sweden)

    Yu.M. Vaskovskyi

    2016-09-01

    Full Text Available Electromagnetic vibration disturbing forces in different variants of the rotor displacement from an axis of the stator bore is carried out. Investigation for ТG type ТGV-200-2 by finite element method in COMSOL Multiphysics is carried out. The field mathematical model of static and dynamic eccentricity is described. The amplitude vibration disturbing forces are greatest, when a static eccentricity direction coincides with an axis of the stator winding phase is shown. The diagnostic features static and dynamic eccentricities are formulated. The most value of forces in the point with minimal air gap is shown. The diagnostic features static and dynamic eccentricities and the method of diagnostic eccentricity are formulated. Diagnostic feature of static eccentricity is to change the amplitude Maxwell stress tensor is established. The dynamic eccentricity diagnostic features are appearance in the spectrum of vibration disturbing forces rotating and multiple harmonics.

  14. Bearing Capacity Analysis of N90T20 Rack Column Under Eccentric Compression

    Directory of Open Access Journals (Sweden)

    Hao Jianing

    2016-01-01

    Full Text Available The bearing capacity of cold-formed porous steel N90T20 rack column is studied, the eccentric positions, the spacing between holes, column thickness are discussed in details. The results obtained from this study demonstrate that when eccentric space is small, eccentric compression weaken column ultimate bearing capacity is small. From the results, it is clear that when eccentric space is large, eccentric compression can cause the column ultimate bearing capacity of plummeting. If the eccentricity is close proximity to the web, the ultimate bearing capacity declines to be smaller than the eccentric near the curling side of the column. The spacing of the holes on the column web do not present significant effect to the ultimate bearing capacity of the column. The wall thickness of column component greatly influence on the ultimate bearing capacity of the columns. This study makes contribution to the N90T20 rack design in the engineering practice and research areas.

  15. Effects of High Inclined and Eccentric Disturbers on the Dynamics of the Equator of an Axy-Simmetric Body

    Science.gov (United States)

    Yokoyama, Tadashi; Frouard, J. H.; Deienno, R.

    2013-05-01

    Abstract (2,250 Maximum Characters): In this work we consider the rotational long term dynamics of an axy-simmetric body under the action of a high inclined and eccentric disturber. The problem is written in terms of Andoyer canonical variables (L,G,H, l,g,h), with respect to an independent inertial frame. Since A=B (moments of inertia ), the l angle is an ignorable variable, so that spin-orbit resonance is ruled out. Therefore the Hamiltonian can be averaged in the mean anomaly of the orbital motion of the disturber. An extra average is still possible in g as it is a fast Andoyer variable. In order to have a first and rough idea of the real dynamics, the disturber is assumed in a simplified precessing keplerian motion (Henrard & Schwanen, 2004) . Then the Hamiltonian is reduced to a problem of one degree of freedom and the level curves show a gross idea of the basic dynamics. In particular the curves show interesting equilibrium points, some of them are related to Cassini’s second law. Depending on the mass and eccentricity or inclination of the disturber, a strong resonance between h and longitude of the node of the disturber can appear. This resonance can cause interesting variations of the inclination of the plane normal to the angular momentum of the perturbed body. Finally, numerical integrations of the complete averaged problem are performed. In particular, we study the possible cumulative effects of temporary satellites when they orbit their host planet in high inclined and eccentric orbit. These satellites ( planetesimals) might have existed during the planetary migration but due to Lidov-Kozai resonance they should have ejected after some time.

  16. Perturbative and Non-Perturbative Aspects of N=8 Supergravity

    CERN Document Server

    Ferrara, Sergio

    2011-01-01

    Some aspects of quantum properties of N=8 supergravity in four dimensions are discussed for non-practitioners. At perturbative level, they include the Weyl trace anomaly as well as composite duality anomalies, the latter being relevant for perturbative finiteness. At non-perturbative level, we briefly review some facts about extremal black holes, their Bekenstein-Hawking entropy and attractor flows for single- and two-centered solutions.

  17. Flow instability and vortex street in eccentric annular channels

    Science.gov (United States)

    Choueiri, George; Tavoularis, Stavros

    2013-11-01

    Flow development in an eccentric annular channel with a diameter ratio of 0.5 has been investigated using flow visualization, two-component laser Doppler velocimetry and planar and stereoscopic particle image velocimetry. The eccentricity e was varied between 0.3 and 0.9 and the Reynolds number was 1000 flow instability and the generation of a quasi-periodic vortex street, which manifested itself by strong cross-flows across the gap and an increase in axial velocity in the gap region, but also affected the flow in the entire channel. The vortex strength was highest for e ~ 0 . 7 and the Strouhal number of the cross-flow oscillations (based on bulk velocity and core diameter) increased with increasing Re, reaching an asymptote near 0.12 for Re >= 10000 . Supported by NSERC and AECL.

  18. Tidal disruption flares from stars on eccentric orbits

    Directory of Open Access Journals (Sweden)

    Loeb A.

    2012-12-01

    Full Text Available We study tidal disruption and subsequent mass fallback for stars approaching supermassive black holes on bound orbits, by performing three dimensional Smoothed Particle Hydrodynamics simulations with a pseudo-Newtonian potential. We find that the mass fallback rate decays with the expected -5/3 power of time for parabolic orbits, albeit with a slight deviation due to the self-gravity of the stellar debris. For eccentric orbits, however, there is a critical value of the orbital eccentricity, significantly below which all of the stellar debris is bound to the supermassive black hole. All the mass therefore falls back to the supermassive black hole in a much shorter time than in the standard, parabolic case. The resultant mass fallback rate considerably exceeds the Eddington accretion rate and substantially differs from the -5/3 power of time.

  19. Low frequency axisymmetric longitudinal guided waves in eccentric annular cylinders.

    Science.gov (United States)

    Pattanayak, Roson Kumar; Manogharan, Prabhakaran; Balasubramaniam, Krishnan; Rajagopal, Prabhu

    2015-06-01

    This paper studies the effect of axially uniform eccentricity on the modal structures and velocities of the lower order axisymmetric guided wave mode L(0,2) in circular tubes or pipes. The semi-analytical finite element method is mainly used, supported by fully three-dimensional finite element models and validated using experiments. The studies show that even a small eccentricity in the pipe can cause a loss in the L(0,2) mode axisymmetry, leading to its confinement in the thinned side of the pipe cross-section and also a reduction in mode velocities. The physics of this phenomenon is related to the feature-guiding and mode confinement effects noted in recent years in the literature, particularly studies on waveguides with local cross-section variations and curvature.

  20. An Eccentric Binary Millisecond Pulsar in the Galactic Plane

    Science.gov (United States)

    Champion, David J.; Ransom, Scott M.; Lazarus, Patrick; Camilo, Fernando; Bassa, Cess; Kaspi, Victoria M.; Nice, David J.; Freire, Paulo C. C.; Stairs, Ingrid H.; vanLeeuwen, Joeri; hide

    2008-01-01

    Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M.) companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster, then ejecting it into the Galactic disk, or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74 +/- 0.04 Solar Mass, an unusually high value.

  1. An eccentric binary millisecond pulsar in the galactic plane.

    Science.gov (United States)

    Champion, David J; Ransom, Scott M; Lazarus, Patrick; Camilo, Fernando; Bassa, Cees; Kaspi, Victoria M; Nice, David J; Freire, Paulo C C; Stairs, Ingrid H; van Leeuwen, Joeri; Stappers, Ben W; Cordes, James M; Hessels, Jason W T; Lorimer, Duncan R; Arzoumanian, Zaven; Backer, Don C; Bhat, N D Ramesh; Chatterjee, Shami; Cognard, Ismaël; Deneva, Julia S; Faucher-Giguère, Claude-André; Gaensler, Bryan M; Han, Jinlin; Jenet, Fredrick A; Kasian, Laura; Kondratiev, Vlad I; Kramer, Michael; Lazio, Joseph; McLaughlin, Maura A; Venkataraman, Arun; Vlemmings, Wouter

    2008-06-06

    Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M(middle dot in circle)) companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster, then ejecting it into the Galactic disk, or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74 +/- 0.04 M solar symbol, an unusually high value.

  2. Progressive coxa vara by eccentric growth tethering in immature pigs.

    Science.gov (United States)

    Chang, Chia-Hsieh; Chi, Chau-Hwa; Lee, Zhon-Liau

    2006-07-01

    The present study tested progressive coxa vara by eccentric growth tethering that might be used to correct coxa valga in cerebral palsy. Eight young pigs received screw fixation at inferior portion of right femoral head at age 4 months and were killed at age 7.25 months for bilateral femurs for comparison. The neck-shaft angle at the tethered side was significantly less than that at the control side (129.8 vs. 138.3 degrees , P<0.05). Histological study showed bony bar formation. Eccentric growth tethering by one screw resulted in a reduction of neck-shaft angle by 8.5 degrees and shortening of femoral length by 4%.

  3. Functional changes of human quadriceps muscle injured by eccentric exercise

    Directory of Open Access Journals (Sweden)

    F.V. Serrão

    2003-06-01

    Full Text Available The present study evaluated functional changes of quadriceps muscle after injury induced by eccentric exercise. Maximal isometric torque of quadriceps and the surface electromyography (root mean square, RMS, and median frequency, MDF of the vastus medialis oblique (VMO and vastus lateralis (VL muscles were examined before, immediately after and during the first 7 days after injury. Serum creatine kinase (CK levels and magnetic resonance imaging (MRI were used to identify muscle injury. The subject was used as her own control and percent refers to pre-injury data. Experiments were carried out with a sedentary 23-year-old female. Injury was induced by 4 bouts of 15 maximal isokinetic eccentric contractions (angular velocity of 5º/s; range of motion from 40º to 110º of knee flexion. The isometric torque of the quadriceps (knee at 90º flexion decreased 52% immediately after eccentric exercise and recovered on the 5th day. The highest reduction of RMS occurred on the 2nd day after injury in both VL (63% and VMO (66% and only VL recovered to the pre-injury level on the 7th day. Immediately after injury, the MDF decreased by 5 and 3% (VMO and VL, respectively and recovered one day later. Serum CK levels increased by 109% on the 2nd day and were still increased by 32% on the 7th day. MRI showed large areas of injury especially in the deep region of quadriceps. In conclusion, eccentric exercise decreased the isometric torque and electromyographic signals of quadriceps muscle, which were recovered in one week, despite the muscle regeneration signals.

  4. Experimental Investigations on Axially and Eccentrically Loaded Masonry Walls

    Science.gov (United States)

    Keshava, Mangala; Raghunath, Seshagiri Rao

    2017-12-01

    In India, un-reinforced masonry walls are often used as main structural components in load bearing structures. Indian code on masonry accounts the reduction in strength of walls by using stress reduction factors in its design philosophy. This code was introduced in 1987 and reaffirmed in 1995. The present study investigates the use of these factors for south Indian masonry. Also, with the gaining popularity in block work construction, the aim of this study was to find out the suitability of these factors given in the Indian code to block work masonry. Normally, the load carrying capacity of masonry walls can be assessed in three ways, namely, (1) tests on masonry constituents, (2) tests on masonry prisms and (3) tests on full-scale wall specimens. Tests on bricks/blocks, cement-sand mortar, brick/block masonry prisms and 14 full-scale brick/block masonry walls formed the experimental investigation. The behavior of the walls was investigated under varying slenderness and eccentricity ratios. Hollow concrete blocks normally used as in-fill masonry can be considered as load bearing elements as its load carrying capacity was found to be high when compared to conventional brick masonry. Higher slenderness and eccentricity ratios drastically reduced the strength capacity of south Indian brick masonry walls. The reduction in strength due to slenderness and eccentricity is presented in the form of stress reduction factors in the Indian code. These factors obtained through experiments on eccentrically loaded brick masonry walls was lower while that of brick/block masonry under axial loads was higher than the values indicated in the Indian code. Also the reduction in strength is different for brick and block work masonry thus indicating the need for separate stress reduction factors for these two masonry materials.

  5. WHY ARE ECCENTRIC EXERCISES EFFECTIVE FOR ACHILLES TENDINOPATHY?

    OpenAIRE

    O’Neill, Seth; Watson, Paul J; Barry, Simon

    2015-01-01

    Achilles Tendinopathy is a complex problem, with the most common conservative treatment being eccentric exercises. Despite multiple studies assessing this treatment regime little is known about the mechanism of effect. This lack of understanding may be hindering therapeutic care and preventing optimal rehabilitation. Of the mechanisms proposed, most relate to tendon adaptation and fail to consider other possibilities. The current consensus is that tendon adaptation does not occur within timef...

  6. The Effects of Spatial Endogenous Pre-cueing across Eccentricities

    Directory of Open Access Journals (Sweden)

    Jing Feng

    2017-06-01

    Full Text Available Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas, how endogenous pre-cues that carry spatial information of targets influence our allocation of attention across a large visual field (especially in the more peripheral areas remains unclear. We present two experiments examining how the expectation of the location of the target shapes the distribution of attention across eccentricities in the visual field. We measured participants’ ability to pick out a target among distractors in the visual field after the presentation of a highly valid cue indicating the size of the area in which the target was likely to occur, or the likely direction of the target (left or right side of the display. Our first experiment showed that participants had a higher target detection rate with faster responses, particularly at eccentricities of 20° and 30°. There was also a marginal advantage of pre-cueing effects when trials of the same size cue were blocked compared to when trials were mixed. Experiment 2 demonstrated a higher target detection rate when the target occurred at the cued direction. This pre-cueing effect was greater at larger eccentricities and with a longer cue-target interval. Our findings on the endogenous pre-cueing effects across a large visual area were summarized using a simple model to assist in conceptualizing the modifications of the distribution of attention over the visual field. We discuss our finding in light of cognitive penetration of perception, and highlight the importance of examining

  7. António Reis and Margarida Cordeiro, eccentric filmmakers

    Directory of Open Access Journals (Sweden)

    Lucas Tavares Neves

    2016-02-01

    Full Text Available The international symposium "António Reis and Margarida Cordeiro, eccentric filmmakers" took place in Paris between the 3rd and the 4th of June, 2015. Speakers exchanged on the political, social and poetical aspects of the duo's cinematography, as well as on the reverberations of titles such as Jaime (1974 and Trás-os-montes (1976 on the Portuguese filmic landscape of the decades that followed.

  8. Gluon field fluctuations in nuclear collisions: Multiplicity and eccentricity distributions

    Energy Technology Data Exchange (ETDEWEB)

    Schenke, Björn [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Tribedy, Prithwish [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Venugopalan, Raju [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-06-15

    We discuss different sources of fluctuations in nuclear collisions and their realization in the IP-Glasma model. We present results for multiplicity distributions in p+p and p+A collisions and compare eccentricity (ε{sub 2}, ε{sub 3}, ε{sub 4}) distributions in A + A collisions to the v{sub n} distributions in 10 centrality classes measured by the ATLAS Collaboration.

  9. Muscle preservation in long duration space missions: The eccentric factor

    Science.gov (United States)

    Buchanan, Paul; Dudley, Gary A.; Tesch, Per A.; Hather, Bruce M.

    1990-01-01

    In our quest to understand, and eventually prevent, the loss of muscle strength and mass that occurs during prolonged periods in microgravity, we have organized our research approach by systems and useful terrestrial analogs. Our hypothesis was that: The eccentric movement, or lengthening component, of dynamic, resistive exercise, is required for the production of the greatest gains in strength and muscle hypertrophy in the most metabolically efficient, and time effective manner. The exercises selected were leg presses, leg (knee) extensions, and hamstring curls. In this 30 week study, 38 male subjects, between the ages of 25 and 50, were divided into four groups. One group performed 5 sets of 8-12 repetitions per set of conventional concentric/eccentric (CON/ECC) exercises. Another group performed only the concentric (CON) movement on the same schedule. The third group performed twice the number of sets in the concentric only mode (CON/CON), and the last group served as controls. We interpret these data as convincing evidence that the eccentric component of heavy resistance training is required along with the concentric for the most effective increase in strength and muscle fiber size in the least time. We also conclude that such heavy exercise of any such muscle group need not consume inordinately long periods of time, and is quite satisfactorily effective when performed on 72 hour centers.

  10. Processes involved in oculomotor adaptation to eccentric reading.

    Science.gov (United States)

    Fornos, Angélica Pérez; Sommerhalder, Jörg; Rappaz, Benjamin; Pelizzone, Marco; Safran, Avinoam B

    2006-04-01

    Adaptation to eccentric viewing in subjects with a central scotoma remains poorly understood. The purpose of this study was to analyze the adaptation stages of oculomotor control to forced eccentric reading in normal subjects. Three normal adults (25.7 +/- 3.8 years of age) were trained to read full-page texts using a restricted 10 degrees x 7 degrees viewing window stabilized at 15 degrees eccentricity (lower visual field). Gaze position was recorded throughout the training period (1 hour per day for approximately 6 weeks). In the first sessions, eye movements appeared inappropriate for reading, mainly consisting of reflexive vertical (foveating) saccades. In early adaptation phases, both vertical saccade count and amplitude dramatically decreased. Horizontal saccade frequency increased in the first experimental sessions, then slowly decreased after 7 to 15 sessions. Amplitude of horizontal saccades increased with training. Gradually, accurate line jumps appeared, the proportion of progressive saccades increased, and the proportion of regressive saccades decreased. At the end of the learning process, eye movements mainly consisted of horizontal progressions, line jumps, and a few horizontal regressions. Two main adaptation phases were distinguished: a "faster" vertical process aimed at suppressing reflexive foveation and a "slower" restructuring of the horizontal eye movement pattern. The vertical phase consisted of a rapid reduction in the number of vertical saccades and a rapid but more progressive adjustment of remaining vertical saccades. The horizontal phase involved the amplitude adjustment of horizontal saccades (mainly progressions) to the text presented and the reduction of regressions required.

  11. Final state predictions for J2 gravity perturbed motion of the Earth’s artificial satellites using Bispherical coordinates

    Directory of Open Access Journals (Sweden)

    M.A. Sharaf

    2013-06-01

    Full Text Available In this paper, initial value problem for dynamical astronomy will be established using Bispherical coordinates. A computational algorithm is developed for the final state predictions for J2 gravity perturbed motion of the Earth’s artificial satellites. This algorithm is important in targeting, rendezvous maneuvers as well for scientific researches. The applications of the algorithm are illustrated by numerical examples of some test orbits of different eccentricities. The numerical results are extremely accurate and efficient.

  12. On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

    Science.gov (United States)

    Hamers, Adrian S.

    2017-04-01

    Hot Jupiters (HJs) are Jupiter-like planets orbiting their host star in tight orbits of a few days. They are commonly believed not to have formed in situ, requiring inwards migration towards the host star. One of the proposed migration scenarios is secular high-eccentricity or high-e migration, in which the orbit of the planet is perturbed to high eccentricity by secular processes, triggering strong tidal evolution and orbital migration. Previous theoretical studies have considered secular excitation in stellar binaries. Recently, a number of HJs have been observed in stellar triple systems. In the latter, the secular dynamics are much richer compared to stellar binaries, and HJs could potentially be formed more efficiently. Here, we investigate this possibility by modelling the secular dynamical and tidal evolution of planets in two hierarchical configurations in stellar triple systems. We find that the HJ formation efficiency is higher compared to stellar binaries, but only by at most a few tens of per cent. The orbital properties of the HJs formed in the simulations are very similar to HJs formed in stellar binaries, and similarly to studies of the latter we find no significant number of warm Jupiters. HJs are only formed in our simulations for triples with specific orbital configurations, and our constraints are approximately consistent with current observations. In future, this allows us to rule out high-e migration in stellar triples if a HJ is detected in a triple grossly violating these constraints.

  13. Perturbed effects at radiation physics

    Science.gov (United States)

    Külahcı, Fatih; Şen, Zekâi

    2013-09-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer-Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables.

  14. Applications Of Chiral Perturbation Theory

    CERN Document Server

    Mohta, V

    2005-01-01

    Effective field theory techniques are used to describe the spectrum and interactions of hadrons. The mathematics of classical field theory and perturbative quantum field theory are reviewed. The physics of effective field theory and, in particular, of chiral perturbation theory and heavy baryon chiral perturbation theory are also reviewed. The geometry underlying heavy baryon chiral perturbation theory is described in detail. Results by Coleman et. al. in the physics literature are stated precisely and proven. A chiral perturbation theory is developed for a multiplet containing the recently- observed exotic baryons. A small coupling expansion is identified that allows the calculation of self-energy corrections to the exotic baryon masses. Opportunities in lattice calculations are discussed. Chiral perturbation theory is used to study the possibility of two multiplets of exotic baryons mixed by quark masses. A new symmetry constraint on reduced partial widths is identified. Predictions in the literature based ...

  15. Perturbative Gadgets at Arbitrary Orders

    OpenAIRE

    Jordan, Stephen P.; Farhi, Edward

    2008-01-01

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets...

  16. Climate of an Earth-Like World with Changing Eccentricity

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Having a giant planet like Jupiter next door can really wreak havoc on your orbit! A new study examines what such a bad neighbor might mean for the long-term climate of an Earth-like planet.Influence of a Bad NeighborThe presence of a Jupiter-like giant planet in a nearby orbit can significantly affect how terrestrial planets evolve dynamically, causing elements like the planets orbital eccentricities and axial tilts to change over time. Earth is saved this inconvenience Jupiter isnt close enough to significantly influence us, and our large moon stabilizes our orbit against Jupiters tugs.Top panels: Authors simulationoutcomes for Case1, in which the planets eccentricity varies from 0 to 0.283 over 6500 years. Bottom panels: Outcomes for Case 2, in which the planets eccentricity varies from 0 to 0.066 over 4500 years. The highereccentricities reached in Case 1 causes the climate parameters to vary more widely. Click for a better look! [Way Georgakarakos 2017]Mars, on the other hand, isnt as lucky: its possible that Jupiters gravitational pull causes Marss axial tilt, for instance, to evolve through a range as large as 0 to 60 degrees on timescales of millions of years! Marss orbital eccentricity is similarly thought to vary due to Jupiters influence, and both of these factors play a major role in determining Marss climate.As exoplanet missions discover more planets many of which are Earth-like we must carefully consider which among these are most likely to be capable of sustaining life. If having a nearby neighbor like a Jupiter can tug an Earth-like world into an orbit with varying eccentricity, how does this affect the planets climate? Will the planet remain temperate? Or will it develop a runaway heating or cooling effect as it orbits, rendering it uninhabitable?Oceans and OrbitsTo examine these questions, two scientists have built the first ever 3D global climate model simulations of an Earth-like world using a fully coupled ocean (necessary for understanding

  17. Effects of eccentric versus concentric training on thigh muscle strength and EMG.

    Science.gov (United States)

    Seger, J Y; Thorstensson, A

    2005-01-01

    The purpose of this study was to compare pure eccentric and concentric strength training regarding possible specific effects of muscle action type on neuromuscular parameters, such as a decreased inhibition during maximal voluntary eccentric actions. Two groups of young healthy adult men performed 10 weeks of either eccentric or concentric unilateral isokinetic knee extensor training at 90 degrees.s(-1), 4 sets of 10 maximal efforts, 3 days a week. Knee extensor torque and surface EMG from the quadriceps and hamstring muscle groups were collected and quantified in a window between 30 and 70 degrees knee angle (range of motion 90-5 degrees ) during maximal voluntary eccentric and concentric knee extensor actions at 30, 90, and 270 degrees.s(-1). Changes in strength of the trained legs revealed more signs of specificity related to velocity and contraction type after eccentric than concentric training. No major training effects were present in eccentric to concentric ratios of agonist EMG or in relative antagonist (hamstring) activation. Thus, for the trained leg, the muscle action type and speed specific changes in maximal voluntary eccentric strength could not be related to any effects on neural mechanisms, such as a selective increase in muscle activation during eccentric actions. Interestingly, with both types of training there were specific cross-education effects, that is, action type and velocity specific increases in strength occurred in the contralateral, untrained, leg, accompanied by a specific increase in eccentric to concentric EMG ratio after eccentric training.

  18. High eccentricity MMRs in the circular planar restricted three-body problem

    Science.gov (United States)

    Wang, Xianyu; Malhotra, Renu

    2016-05-01

    Mean motion resonances [MMRs] play an important role in the evolution of the solar system and have significantly influenced the population of the minor planets. Most previous theoretical analyses of mean motion resonances have focused on the low eccentricity regime, but with new discoveries of high eccentricity resonant minor planets and even exoplanets, there is increasing motivation to examine the dynamics of MMRs in the high eccentricity regime. Here we report on a study of the high eccentricity regime of MMRs in the circular planar restricted three-body problem. Numerical analysis of several important interior and exterior resonances are performed for a wide range of secondary-to-primary mass ratio µ, and for a wide range of eccentricity of the particle. The surface of section of a vs. ψ is used to study the stable resonant regions, where a is the semi-major axis and ψ is the angle between the planet and the particle at periapse; the usual resonant argument is an integer multiple of ψ. We find that for each resonant ratio, the center and extent of stable librations of ψ changes depending upon the eccentricity and mass ratio µ. Some libration centers that are stable at lower eccentricity become unstable and chaotic at higher eccentricity. However, large new stable islands reappear at higher eccentricity, albeit at shifted libration centers. We discuss the mass and eccentricity dependence of the centers and widths of stable resonance zones.

  19. Perturbative quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1979-12-01

    The application of QCD to hadron dynamics at short distances, where asymptotic freedom allows a systematic perturbative approach, is addressed. The main theme of the approach is to incorporate systematically the effects of the hadronic wave function in large momentum transfer exclusive and inclusive reactions. Although it is conventional to treat the hadron as a classical source of on-shell quarks, there are important dynamical effects due to hadronic constituent structure which lead to a broader testing ground for QCD. QCD predictions are discussed for exclusive processes and form factors at large momentum transfer in which the short-distance behavior and the finite compositeness of the hadronic wave functions play crucial roles. Many of the standard tests of QCD are reviewed including the predictions for R = sigma/sub e/sup +/e/sup -/..-->..had//sigma/sub e/sup +/e/sup -/..--> mu../sup +/..mu../sup -//, the structure functions of hadrons and photons, jet phenomena, and the QCD corrections to deep inelastic processes. The exclusive-inclusive connection in QCD, the effects of power-law scale-breaking contributions, and the important role of the available energy in controlling logarithmic scale violations are also discussed. 150 references, 44 figures. (RWR)

  20. Propagation of Ion Acoustic Perturbations

    DEFF Research Database (Denmark)

    Pécseli, Hans

    1975-01-01

    Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered.......Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered....

  1. Inversion of the perturbation series

    Energy Technology Data Exchange (ETDEWEB)

    Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Division Quimica Teorica, Diag 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2008-01-18

    We investigate the inversion of the perturbation series and its resummation, and prove that it is related to a recently developed parametric perturbation theory. Results for some illustrative examples show that in some cases series reversion may improve the accuracy of the results.

  2. Path integral for inflationary perturbations

    NARCIS (Netherlands)

    Prokopec, T.; Rigopoulos, G.

    2010-01-01

    The quantum theory of cosmological perturbations in single-field inflation is formulated in terms of a path integral. Starting from a canonical formulation, we show how the free propagators can be obtained from the well-known gauge-invariant quadratic action for scalar and tensor perturbations, and

  3. Perturbative QCD (1/3)

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Perturbative QCD is the general theoretical framework for describing hard scattering processes yielding multiparticle production at hadron colliders. In these lectures, we shall introduce fundamental features of perturbative QCD and describe its application to several high energy collider processes, including jet production in electron-positron annihilation, deep inelastic scattering, Higgs boson and gauge boson production at the LHC.

  4. Measurement accuracy of articulated arm CMMs with circular grating eccentricity errors

    Science.gov (United States)

    Zheng, Dateng; Yin, Sanfeng; Luo, Zhiyang; Zhang, Jing; Zhou, Taiping

    2016-11-01

    The 6 circular grating eccentricity errors model attempts to improve the measurement accuracy of an articulated arm coordinate measuring machine (AACMM) without increasing the corresponding hardware cost. We analyzed the AACMM’s circular grating eccentricity and obtained the 6 joints’ circular grating eccentricity error model parameters by conducting circular grating eccentricity error experiments. We completed the calibration operations for the measurement models by using home-made standard bar components. Our results show that the measurement errors from the AACMM’s measurement model without and with circular grating eccentricity errors are 0.0834 mm and 0.0462 mm, respectively. Significantly, we determined that measurement accuracy increased by about 44.6% when the circular grating eccentricity errors were corrected. This study is significant because it promotes wider applications of AACMMs both in theory and in practice.

  5. Eccentric activation and muscle damage: biomechanical and physiological considerations during downhill running.

    OpenAIRE

    Eston, R. G.; Mickleborough, J; Baltzopoulos, V

    1995-01-01

    An eccentric muscle activation is the controlled lengthening of the muscle under tension. Functionally, most leg muscles work eccentrically for some part of a normal gait cycle, to support the weight of the body against gravity and to absorb shock. During downhill running the role of eccentric work of the 'anti-gravity' muscles--knee extensors, muscles of the anterior and posterior tibial compartments and hip extensors--is accentuated. The purpose of this paper is to review the relationship b...

  6. Similar substrate oxidation rates in concentric and eccentric cycling matched for aerobic power output.

    Science.gov (United States)

    Isacco, Laurie; Ritter, Ophélie; Tordi, Nicolas; Laroche, Davy; Degano, Bruno; Bouhaddi, Malika; Rakobowchuk, Mark; Mourot, Laurent

    2016-11-01

    This study investigated substrate oxidation in concentric and eccentric cycling matched for aerobic power output in the postprandial state. Energy expenditure, respiratory exchange ratio, and fat and carbohydrate oxidation rates were measured at rest and after 15, 30, and 45 min of eccentric and concentric cycling in 12 men. Absolute and relative aerobic power output and energy expenditure were similar during concentric and eccentric exercise. No effect of exercise modality was observed for substrate metabolism.

  7. Grounding after moderate eccentric contractions reduces muscle damage.

    Science.gov (United States)

    Brown, Richard; Chevalier, Gaétan; Hill, Michael

    2015-01-01

    Grounding a human to the earth has resulted in changes in the physiology of the body. A pilot study on grounding and eccentric contractions demonstrated shortened duration of pain, reduced creatine kinase (CK), and differences in blood parameters. This follow-up study was conducted to investigate the effects of grounding after moderate eccentric contractions on pain, CK, and complete blood counts. Thirty-two healthy young men were randomly divided into grounded (n=16) and sham-grounded (n=16) groups. On days 1 through 4, visual analog scale for pain evaluations and blood draws were accomplished. On day 1, the participants performed eccentric contractions of 200 half-knee bends. They were then grounded or sham-grounded to the earth for 4 hours on days 1 and 2. Both groups experienced pain on all posttest days. On day 2, the sham-grounded group experienced significant CK increase (Pgrounded group did not increase significantly; the between-group difference was significant (P=0.04). There was also an increase in the neutrophils of the grounded group on day 3 (P=0.05) compared to the sham-grounded group. There was a significant increase in platelets in the grounded group on days 2 through 4. Grounding produced changes in CK and complete blood counts that were not shared by the sham-grounded group. Grounding significantly reduced the loss of CK from the injured muscles indicating reduced muscle damage. These results warrant further study on the effects of earthing on delayed onset muscle damage.

  8. Eccentricity samples: Implications on the potential and the velocity distribution

    Directory of Open Access Journals (Sweden)

    Cubarsi R.

    2017-01-01

    Full Text Available Planar and vertical epicycle frequencies and local angular velocity are related to the derivatives up to the second order of the local potential and can be used to test the shape of the potential from stellar disc samples. These samples show a more complex velocity distribution than halo stars and should provide a more realistic test. We assume an axisymmetric potential allowing a mixture of independent ellipsoidal velocity distributions, of separable or Staeckel form in cylindrical or spherical coordinates. We prove that values of local constants are not consistent with a potential separable in addition in cylindrical coordinates and with a spherically symmetric potential. The simplest potential that fits the local constants is used to show that the harmonical and non-harmonical terms of the potential are equally important. The same analysis is used to estimate the local constants. Two families of nested subsamples selected for decreasing planar and vertical eccentricities are used to borne out the relation between the mean squared planar and vertical eccentricities and the velocity dispersions of the subsamples. According to the first-order epicycle model, the radial and vertical velocity components provide accurate information on the planar and vertical epicycle frequencies. However, it is impossible to account for the asymmetric drift which introduces a systematic bias in estimation of the third constant. Under a more general model, when the asymmetric drift is taken into account, the rotation velocity dispersions together with their asymmetric drift provide the correct fit for the local angular velocity. The consistency of the results shows that this new method based on the distribution of eccentricities is worth using for kinematic stellar samples. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. No 176011: Dynamics and Kinematics of Celestial Bodies and Systems

  9. The orbital eccentricity distribution of solar-neighbourhood halo stars

    Science.gov (United States)

    Hattori, K.; Yoshii, Y.

    2011-12-01

    We present theoretical calculations for the differential distribution of stellar orbital eccentricity for a sample of solar-neighbourhood halo stars. Two types of static, spherical gravitational potentials are adopted to define the eccentricity e for given energy E and angular momentum L, such as an isochrone potential and a Navarro-Frenk-White potential that can serve as two extreme ends covering in between any realistic potential of the Milky Way halo. The solar-neighbourhood eccentricity distribution ΔN(e) is then formulated, based on a static distribution function of the form f(E, L) in which the velocity anisotropy parameter β monotonically increases in the radial direction away from the galaxy centre, such that β is below unity (near-isotropic velocity dispersion) in the central region and asymptotically approaches ˜1 (radially anisotropic velocity dispersion) in the far distant region of the halo. We find that ΔN(e) sensitively depends upon the radial profile of β, and this sensitivity is used to constrain such a profile in comparison with some observational properties of ΔNobs(e) recently reported by Carollo et al. In particular, the linear e-distribution and the fraction of higher e stars for their sample of solar-neighbourhood inner-halo stars rule out a constant profile of β, contrary to the opposite claim by Bond et al. Our constraint of β≲ 0.5 at the galaxy centre indicates that the violent relaxation that has acted on the inner halo is effective within a scale radius of ˜10 kpc from the galaxy centre. We argue that our result would help to understand the formation and evolution of the Milky Way halo.

  10. Eccentricity Samples: Implications on the Potential and the Velocity Distribution

    Science.gov (United States)

    Cubarsi, R.; Stojanović, M.; Ninković, S.

    2017-06-01

    Planar and vertical epicycle frequencies and local angular velocity are related to the derivatives up to the second order of the local potential and can be used to test the shape of the potential from stellar disc samples. These samples show a more complex velocity distribution than halo stars and should provide a more realistic test. We assume an axisymmetric potential allowing a mixture of independent ellipsoidal velocity distributions, of separable or Staeckel form in cylindrical or spherical coordinates. We prove that values of local constants are not consistent with a potential separable in addition in cylindrical coordinates and with a spherically symmetric potential. The simplest potential that fits the local constants is used to show that the harmonical and non-harmonical terms of the potential are equally important. The same analysis is used to estimate the local constants. Two families of nested subsamples selected for decreasing planar and vertical eccentricities are used to borne out the relation between the mean squared planar and vertical eccentricities and the velocity dispersions of the subsamples. According to the first-order epicycle model, the radial and vertical velocity components provide accurate information on the planar and vertical epicycle frequencies. However, it is impossible to account for the asymmetric drift which introduces a systematic bias in estimation of the third constant. Under a more general model, when the asymmetric drift is taken into account, the rotation velocity dispersions together with their asymmetric drift provide the correct fit for the local angular velocity. The consistency of the results shows that this new method based on the distribution of eccentricities is worth using for kinematic stellar samples.

  11. Nature of occlusion during eccentric mandibular movements in young adults.

    Science.gov (United States)

    Sreekumar, A V; Rupesh, P L; Pradeep, Nishna

    2012-09-01

    The aim of this study was to find out the nature of occlusion and tooth contact during various eccentric mandibular movements in young adults with class I occlusion. The sample consisted of 100 young adults with class I occlusion with full complement of teeth. Anterior disclusion in centric occlusion was demonstrated using a shim stock interposed between the upper and lower anteriors. Disclusion of posteriors was ascertained during 1.5 mm straight protusion and in edge-to-edge protrusion, visually as well as using a silk floss method. Posterior disclusion was also verified during lateroprotrusion and crossover. Besides these occlusal wear of teeth also were observed. The results of this study showed that the anterior disclusion is seen only in one-fourth of the subjects compared to almost three-fourth showing posterior disclusion. Mutually protected occlusion was also seen only in one-fourth of the subjects. Canine protective mechanism is seen in a relatively large number of subjects, but it was not overwhelmingly predominant. No correlation could be established between cuspid wear and the type of occlusion. A relatively high percentage of subjects showed wear on posterior teeth when there was no posterior disclusion. From the above study it is seen that posterior disclusion is acknowledged as a common factor except when a bilateral balance is present. Since bilateral balance is harmful, the ideal occlusal relationship in eccentric movements is in favor of posterior disclusion. Posterior disclusion is easily obtainable when restorations are planned. From the findings and results it has been possible to make some contributions on the nature of tooth contacts and disclusion during various eccentric movements and compare it with the requirements of ideal occlusion.

  12. MHD Flow of the Micropolar Fluid between Eccentrically Rotating Disks.

    Science.gov (United States)

    Srivastava, Neetu

    2014-01-01

    This analytical investigation examines the magnetohydrodynamic flow problem of an incompressible micropolar fluid between the two eccentrically placed disks. Employing suitable transformations, the flow governing partial differential equations is reduced to ordinary differential equations. An exact solution representing the different flow characteristic of micropolar fluid has been derived by solving the ordinary differential equations. Analysis of the flow characteristics of the micropolar fluid has been done graphically by varying the Reynolds number and the Hartmann number. This analysis has been carried out for the weak and strong interactions.

  13. Computing the Ediz eccentric connectivity index of discrete dynamic structures

    Directory of Open Access Journals (Sweden)

    Wu Hualong

    2017-06-01

    Full Text Available From the earlier studies in physical and chemical sciences, it is found that the physico-chemical characteristics of chemical compounds are internally connected with their molecular structures. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. In our article, we study the physico-chemical properties of certain molecular structures via computing the Ediz eccentric connectivity index from mathematical standpoint. The results we yielded mainly apply to the techniques of distance and degree computation of mathematical derivation, and the conclusions have guiding significance in physical engineering.

  14. Biomechanical characteristics of the eccentric Achilles tendon exercise

    DEFF Research Database (Denmark)

    Henriksen, Marius; Aaboe, Jens; Bliddal, Henning

    2009-01-01

    into the biomechanics of the exercise may improve our understanding. METHODS: Sixteen healthy subjects performed one-legged full weight bearing ankle plantar and dorsiflexion exercises during which three-dimensional ground reaction forces (GRF), ankle joint kinematics and surface electromyography (EMG) of the lower leg....... No differences in Achilles tendon loads were found. INTERPRETATION: This descriptive study demonstrates differences in the movement biomechanics between the eccentric and concentric phases of one-legged full weight bearing ankle dorsal and plantar flexion exercises. In particular, the findings imply...

  15. Computing the Ediz eccentric connectivity index of discrete dynamic structures

    Science.gov (United States)

    Wu, Hualong; Kamran Siddiqui, Muhammad; Zhao, Bo; Gan, Jianhou; Gao, Wei

    2017-06-01

    From the earlier studies in physical and chemical sciences, it is found that the physico-chemical characteristics of chemical compounds are internally connected with their molecular structures. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. In our article, we study the physico-chemical properties of certain molecular structures via computing the Ediz eccentric connectivity index from mathematical standpoint. The results we yielded mainly apply to the techniques of distance and degree computation of mathematical derivation, and the conclusions have guiding significance in physical engineering.

  16. Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training

    Directory of Open Access Journals (Sweden)

    Nosratollah Hedayatpour

    2015-01-01

    Full Text Available Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered.

  17. Evolution of eccentricity and inclination of hot protoplanets embedded in radiative discs

    Science.gov (United States)

    Eklund, Henrik; Masset, Frédéric S.

    2017-07-01

    We study the evolution of the eccentricity and inclination of protoplanetary embryos and low-mass protoplanets (from a fraction of an Earth mass to a few Earth masses) embedded in a protoplanetary disc, by means of three-dimensional hydrodynamics calculations with radiative transfer in the diffusion limit. When the protoplanets radiate in the surrounding disc the energy released by the accretion of solids, their eccentricity and inclination experience a growth towards values that depend on the luminosity-to-mass ratio of the planet, which are comparable to the disc's aspect ratio and which are reached over time-scales of a few thousand years. This growth is triggered by the appearance of a hot, underdense region in the vicinity of the planet. The growth rate of the eccentricity is typically three times larger than that of the inclination. In long-term calculations, we find that the excitation of eccentricity and the excitation of inclination are not independent. In the particular case in which a planet has initially a very small eccentricity and inclination, the eccentricity largely overruns the inclination. When the eccentricity reaches its asymptotic value, the growth of inclination is quenched, yielding an eccentric orbit with a very low inclination. As a side result, we find that the eccentricity and inclination of non-luminous planets are damped more vigorously in radiative discs than in isothermal discs.

  18. Classical and quantum simulations of many-body systems

    Energy Technology Data Exchange (ETDEWEB)

    Murg, Valentin

    2008-04-07

    This thesis is devoted to recent developments in the fields of classical and quantum simulations of many-body systems. We describe new classical algorithms that overcome problems apparent in conventional renormalization group and Monte Carlo methods. These algorithms make possible the detailed study of finite temperature properties of 2-D classical and 1-D quantum systems, the investigation of ground states of 2-D frustrated or fermionic systems and the analysis of time evolutions of 2-D quantum systems. Furthermore, we propose new 'analog' quantum simulators that are able to realize interesting models such as a Tonks-Girardeau gas or a frustrated spin-1/2 XY model on a trigonal lattice. These quantum simulators make use of optical lattices and trapped ions and are technically feasible. In fact, the Tonks-Girardeau gas has been realized experimentally and we provide a detailed comparison between the experimental data and the theoretical predictions. (orig.)

  19. Cosmological perturbations beyond linear order

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Cosmological perturbation theory is the standard tool to understand the formation of the large scale structure in the Universe. However, its degree of applicability is limited by the growth of the amplitude of the matter perturbations with time. This problem can be tackled with by using N-body simulations or analytical techniques that go beyond the linear calculation. In my talk, I'll summarise some recent efforts in the latter that ameliorate the bad convergence of the standard perturbative expansion. The new techniques allow better analytical control on observables (as the matter power spectrum) over scales very relevant to understand the expansion history and formation of structure in the Universe.

  20. The role of eccentric exercise in sport injuries rehabilitation.

    Science.gov (United States)

    Frizziero, Antonio; Trainito, Sabina; Oliva, Francesco; Nicoli Aldini, Nicolò; Masiero, Stefano; Maffulli, Nicola

    2014-06-01

    Sports injuries frequently involve tendons, muscles and ligaments. The variable outcome of surgery and medical treatment support early functional treatments. Eccentric exercise (EE) showed effectiveness in the management of Achilles tendinopathy (AT), patellar tendinopathy (PT) and lateral epicondyle tendinopathy (LET). Preliminary results of EE in other tendinopathies and sports injuries suggest its wide prescription in the sport rehabilitation field. A comprehensive search of PubMed, Web of Science, the Cochrane Collaboration Database, Physiotherapy Evidence Database (PEDro), Evidence Based Medicine (EBM) Search review, National Guidelines, Scopus and Google Scholar was performed using keywords such as 'eccentric exercise', 'sports injuries rehabilitation', 'tendinopathy', 'hamstrings strain' 'adductor injuries' and 'ACL reconstruction rehabilitation'. EE, alone or associated with other therapies, represents a feasible, cost-effective and successful tool in the treatment of well-known targets and might be promising in shoulder tendinopathy, adductor-related groin pain, hamstring strains, and ACL rehabilitation. The lack of standardization of protocols, the variable amount, quality and follow-up of studies, the different anatomy and pathophysiology of the therapeutic targets limit the evidence of applicability of EE to sports injuries. The role of pathology and biomechanics in the response to EE should be further investigated. New randomized controlled trials should test the effectiveness of standardized EE regimens to various sites of sports injuries. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Eccentric Exercise, Kinesiology Tape, and Balance in Healthy Men.

    Science.gov (United States)

    Hosp, Simona; Folie, Ramona; Csapo, Robert; Hasler, Michael; Nachbauer, Werner

    2017-07-01

      Deficits in balance have been identified as a possible risk factor for knee injuries in athletes. Despite a lack of evidence for its effectiveness, kinesiology tape (KT) is widely used to prevent knee injuries.   To investigate the influence of KT at the knee joint on balance ability in healthy men after eccentric exercise.   Crossover study.   University laboratory.   Twelve young men with no history of lower limb injury volunteered for the study (age = 23.3 ± 2.6 years). All participants were students enrolled in a sports science program.   Participants performed the balance test with and without KT at the knee joint on 2 separate days.   The ability to maintain balance was assessed during a single-legged-stance test using a computerized balance-stability test system. The test was performed before and after 30 minutes of downhill walking on a treadmill.   Eccentric exercise resulted in a deterioration of balance ability, which was attenuated by the use of KT. Further analyses revealed that the effectiveness of KT depended on the participant's balance status, with the preventive effect being greater in participants presenting with poorer baseline balance ability.   Applied to the knee joint, KT counteracted the exercise-related deterioration of balance ability observed when no tape was used. Participants presenting with below-average balance ability received more benefit from KT. By preventing exercise-related impairment of balance ability, KT might help to reduce the risk of sport-associated knee injuries.

  2. Arterial stiffness results from eccentrically biased downhill running exercise.

    Science.gov (United States)

    Burr, J F; Boulter, M; Beck, K

    2015-03-01

    There is increasing evidence that select forms of exercise are associated with vascular changes that are in opposition to the well-accepted beneficial effects of moderate intensity aerobic exercise. To determine if alterations in arterial stiffness occur following eccentrically accentuated aerobic exercise, and if changes are associated with measures of muscle soreness. Repeated measures experimental cohort. Twelve (m=8/f=4) moderately trained (VO₂max=52.2 ± 7.4 ml kg(-1)min(-1)) participants performed a downhill run at -12° grade using a speed that elicited 60% VO₂max for 40 min. Cardiovascular and muscle soreness measures were collected at baseline and up to 72 h post-running. Muscle soreness peaked at 48 h (p=running is associated with arterial stiffening in the absence of an extremely prolonged duration or fast pace. The timing of alterations coincides with the well-documented inflammatory response that occurs from the muscular insult of downhill running, but whether the observed changes are a result of either systemic or local inflammation is yet unclear. These findings may help to explain evidence of arterial stiffening in long-term runners and following prolonged duration races wherein cumulative eccentric loading is high. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. Perturbative gadgets at arbitrary orders

    Science.gov (United States)

    Jordan, Stephen P.; Farhi, Edward

    2008-06-01

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets have become a standard tool in the theory of quantum computation. Here we construct generalized gadgets so that one can directly obtain arbitrary k -body effective interactions from two-body Hamiltonians. These effective interactions arise from the k th order in perturbation theory.

  4. Review of chiral perturbation theory

    Indian Academy of Sciences (India)

    Abstract. A review of chiral perturbation theory and recent developments on the comparison of its predictions with experiment is presented. Some interesting topics with scope for further elaboration are touched upon.

  5. Perturbation Theory of Embedded Eigenvalues

    DEFF Research Database (Denmark)

    Engelmann, Matthias

    project gives a general and systematic approach to analytic perturbation theory of embedded eigenvalues. The spectral deformation technique originally developed in the theory of dilation analytic potentials in the context of Schrödinger operators is systematized by the use of Mourre theory. The group......We study problems connected to perturbation theory of embedded eigenvalues in two different setups. The first part deals with second order perturbation theory of mass shells in massive translation invariant Nelson type models. To this end an expansion of the eigenvalues w.r.t. fiber parameter up...... of dilations is thereby replaced by the unitary group generated y the conjugate operator. This then allows to treat the perturbation problem with the usual Kato theory....

  6. HD 106906: A Case Study for External Perturbations of a Debris Disk

    Science.gov (United States)

    Nesvold, Erika R.; Naoz, Smadar; Fitzgerald, Michael P.

    2017-03-01

    Models of debris disk morphology are often focused on the effects of a planet orbiting interior to or within the disk. Nonetheless, an exterior planetary-mass perturber can also excite eccentricities in a debris disk, via Laplace-Lagrange secular perturbations in the coplanar case or Kozai-Lidov perturbations for mutually inclined companions and disks. HD 106906 is an ideal example of such a a system, as it harbors a confirmed exterior 11 {M}{Jup} companion at a projected separation of 650 au outside a resolved, asymmetric disk. We use collisional and dynamical simulations to investigate the interactions between the disk and the companion, and to use the disk’s observed morphology to place constraints on the companion’s orbit. We conclude that the disk’s observed morphology is consistent with perturbations from the observed exterior companion. Generalizing this result, we suggest that exterior perturbers, as well as interior planets, should be considered when investigating the cause of observed asymmetries in a debris disk.

  7. Long-term evaluation of eccentric viewing spectacles in patients with bilateral central scotomas.

    NARCIS (Netherlands)

    Verezen, C.A.; Meulendijks, C.F.M.; Hoyng, C.B.; Klevering, B.J.

    2006-01-01

    PURPOSE: Yoked prism spectacles (eccentric viewing spectacles [EVS]) facilitate eccentric viewing in patients with bilateral central scotomas. This study was conducted to evaluate the long-term success and patient satisfaction of this type of low-vision aid. METHODS. In this retrospective

  8. Decrease in eccentric quadriceps and hamstring strength in recreational alpine skiers after prolonged skiing

    Science.gov (United States)

    Koller, Arnold; Fuchs, Birgit; Leichtfried, Veronika; Schobersberger, Wolfgang

    2015-01-01

    Background To effectively prevent injury in recreational alpine skiing, it is important to identify modifiable risk factors that can be targeted through exercise and training. Fatigue is a potential risk factor in recreational skiing, but no investigations have evaluated concentric/eccentric quadriceps and hamstring fatigue in recreational skiers. We tested the hypothesis that recreational skiing is associated with more pronounced eccentric as compared with concentric muscle fatigue. Methods Twenty-four healthy and fit recreational skiers (14 male and 10 female) performed an isokinetic muscle test 1 day before, 1 h after, and 24 h after a 4 h skiing session. The testing protocol consisted of concentric and eccentric quadriceps and hamstring contractions for both legs. Results Eccentric peak hamstring torque (both thighs) and eccentric peak quadriceps torque (left thigh) were reduced in male and female participants (pskiing session. There were no other significant findings. Summary Recreational skiing is associated with prolonged (at least 24 h) eccentric quadriceps (left thigh) and hamstring (both thighs) fatigue in men and women. Eccentric quadriceps and hamstring fatigue may be a potential injury risk factor in male and female recreational skiers. This provides some justification for judicious use of additional eccentric training modalities for alpine skiing. PMID:27900115

  9. Eccentric overload training in patients with a chronic Achilles tendinopathy: a systematic review.

    NARCIS (Netherlands)

    R. de Knikker; T. Takken; J.J. Kingma; Dr. H.M. Wittink

    2007-01-01

    Background: Eccentric overload training seems to be a promising conservative intervention in patients with chronic Achilles tendinopathy. The efficacy of eccentric overload training on the outcome measures of pain and physical functioning are not exactly clear. Study design: Systematic review of the

  10. A Study of Single- and Double-Averaged Second-Order Models to Evaluate Third-Body Perturbation Considering Elliptic Orbits for the Perturbing Body

    Directory of Open Access Journals (Sweden)

    R. C. Domingos

    2013-01-01

    Full Text Available The equations for the variations of the Keplerian elements of the orbit of a spacecraft perturbed by a third body are developed using a single average over the motion of the spacecraft, considering an elliptic orbit for the disturbing body. A comparison is made between this approach and the more used double averaged technique, as well as with the full elliptic restricted three-body problem. The disturbing function is expanded in Legendre polynomials up to the second order in both cases. The equations of motion are obtained from the planetary equations, and several numerical simulations are made to show the evolution of the orbit of the spacecraft. Some characteristics known from the circular perturbing body are studied: circular, elliptic equatorial, and frozen orbits. Different initial eccentricities for the perturbed body are considered, since the effect of this variable is one of the goals of the present study. The results show the impact of this parameter as well as the differences between both models compared to the full elliptic restricted three-body problem. Regions below, near, and above the critical angle of the third-body perturbation are considered, as well as different altitudes for the orbit of the spacecraft.

  11. Orbital perturbations of the Galilean satellites during planetary encounters

    Energy Technology Data Exchange (ETDEWEB)

    Deienno, Rogerio; Nesvorný, David [Southwest Research Institute, Boulder, CO (United States); Vokrouhlický, David [Institute of Astronomy, Charles University, Prague (Czech Republic); Yokoyama, Tadashi, E-mail: rogerio.deienno@gmail.com [Universidade Estadual Paulista, Rio Claro, SP (Brazil)

    2014-08-01

    The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present solar system, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here, we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorný and Morbidelli that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly affected. In the other two, the orbital eccentricities of all moons were excited by encounters, Callisto's semimajor axis changed, and, in a large fraction of trials, the Laplace resonance of the inner three moons was disrupted. The subsequent evolution by tides damps eccentricities and can recapture the moons in the Laplace resonance. A more important constraint is represented by the orbital inclinations of the moons, which can be excited during the encounters and not appreciably damped by tides. We find that one instability case taken from Nesvorný and Morbidelli clearly does not meet this constraint. This shows how the regular satellites of Jupiter can be used to set limits on the properties of encounters in the jumping-Jupiter model, and help us to better understand how the early solar system evolved.

  12. An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

    Science.gov (United States)

    Li, De Z.; Wang, Wilson; Ismail, Fathy

    2017-11-01

    Induction motors (IMs) are commonly used in various industrial applications. To improve energy consumption efficiency, a reliable IM health condition monitoring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is proposed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are synthesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air-gap eccentricity diagnosis. The effectiveness of the proposed harmonic synthesis technique is examined experimentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

  13. Geometrical theory to predict eccentric photorefraction intensity profiles in the human eye

    Science.gov (United States)

    Roorda, Austin; Campbell, Melanie C. W.; Bobier, W. R.

    1995-08-01

    In eccentric photorefraction, light returning from the retina of the eye is photographed by a camera focused on the eye's pupil. We use a geometrical model of eccentric photorefraction to generate intensity profiles across the pupil image. The intensity profiles for three different monochromatic aberration functions induced in a single eye are predicted and show good agreement with the measured eccentric photorefraction intensity profiles. A directional reflection from the retina is incorporated into the calculation. Intensity profiles for symmetric and asymmetric aberrations are generated and measured. The latter profile shows a dependency on the source position and the meridian. The magnitude of the effect of thresholding on measured pattern extents is predicted. Monochromatic aberrations in human eyes will cause deviations in the eccentric photorefraction measurements from traditional crescents caused by defocus and may cause misdiagnoses of ametropia or anisometropia. Our results suggest that measuring refraction along the vertical meridian is preferred for screening studies with the eccentric photorefractor.

  14. Hereditary Effects in Eccentric Compact Binary Inspirals to Third Post-Newtonian Order

    CERN Document Server

    Loutrel, Nicholas

    2016-01-01

    While there has been much success in understanding the orbital dynamics and gravitational wave emission of eccentric compact binaries in the post-Newtonian formalism, some problems still remain. The largest of these concerns hereditary effects: non-linear phenomena related to the scattering off of the background curved spacetime (tails) and to the generation of gravitational waves by gravitational waves (memory). Currently, these hereditary effects are only known numerically for arbitrary eccentricity through infinite sums of Bessel functions, with closed-form, analytic results only available in the small eccentricity limit. We here calculate, for the first time, closed-form, analytic expressions for all hereditary effects to third post-Newtonian order in binaries with arbitrary eccentricity. For the tails, we first asymptotically expand all Bessel functions in high eccentricity and find a superasymptotic series for each enhancement factor, accurate to better than $10^{-3}$ relative to post-Newtonian numerica...

  15. A fourth-order indirect integration method for black hole perturbations: even modes

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Patxi; Spallicci, Alessandro D A M [Universite d' Orleans, Observatoire des Sciences de l' Univers en region Centre, LPC2E Campus CNRS, 3A Av. Recherche Scientifique, 45071 Orleans (France); Aoudia, Sofiane [Max Planck Institut fuer Gravitationphysik, A Einstein, Am Muehlenberg 1, 14476 Potsdam (Germany); Cordier, Stephane, E-mail: spallicci@cnrs-orleans.fr [Universite d' Orleans, Laboratoire de Mathematiques-Analyse, Probabilites, Modelisation-Orleans, MAPMO, Rue de Chartres, 45067 Orleans (France)

    2011-07-07

    On the basis of a recently proposed strategy of finite element integration in time domain for partial differential equations with a singular source term, we present a fourth-order algorithm for non-rotating black hole perturbations in the Regge-Wheeler gauge. Herein, we address even perturbations induced by a particle plunging in. The forward time value at the upper node of the (r*, t) grid cell is obtained by an algebraic sum of (i) the preceding node values of the same cell, (ii) analytic expressions, related to the jump conditions on the wavefunction and its derivatives and (iii) the values of the wavefunction at adjacent cells. In this approach, the numerical integration does not deal with the source and potential terms directly, for cells crossed by the particle world line. This scheme has also been applied to circular and eccentric orbits and it will be the object of a forthcoming publication.

  16. Probing Gravitational Theories with Eccentric Eclipsing Detached Binary Stars

    Directory of Open Access Journals (Sweden)

    Leopoldo Milano

    2014-12-01

    Full Text Available In this paper, we compare the effects of different theories of gravitation on the apsidal motion of eccentric eclipsing detached binary stars. The comparison is performed by using the formalism of the post-Newtonian parametrization to calculate the theoretical advance at periastron and compare it to the observed one, after having considered the effects of the structure and rotation of the involved stars. A variance analysis on the results of this comparison shows that no signicant difference can be found due to the effect of the different theories under test with respect to the standard general relativity (GR. It will be possible to observe differences, as we would expect, by checking the observed period variation on a much larger lapse of time.

  17. Importance of eccentric actions in performance adaptations to resistance training

    Science.gov (United States)

    Dudley, Gary A.; Miller, Bruce J.; Buchanan, Paul; Tesch, Per A.

    1991-01-01

    The importance of eccentric (ecc) muscle actions in resistance training for the maintenance of muscle strength and mass in hypogravity was investigated in experiments in which human subjects, divided into three groups, were asked to perform four-five sets of 6 to 12 repetitions (rep) per set of three leg press and leg extension exercises, 2 days each weeks for 19 weeks. One group, labeled 'con', performed each rep with only concentric (con) actions, while group con/ecc with performed each rep with only ecc actions; the third group, con/con, performed twice as many sets with only con actions. Control subjects did not train. It was found that resistance training wih both con and ecc actions induced greater increases in muscle strength than did training with only con actions.

  18. Xanthine oxidase in human skeletal muscle following eccentric exercise

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Frandsen, Ulrik; Orthenblad, N.

    1997-01-01

    1. The present study tested the hypothesis that the level of xanthine oxidase is elevated in injured human skeletal muscle in association with inflammatory events. Seven male subjects performed five bouts of strenuous one-legged eccentric exercise. Muscle biopsies from both the exercised...... and the control leg, together with venous blood samples, were obtained prior to exercise and at 45 min, 24, 48 and 96 h after exercise. The time courses of xanthine oxidase immunoreactivity and indicators of muscle damage and inflammation were examined. 2. The number of xanthine oxidase structures observed...... by immunohistological methods in the exercised muscle was up to eightfold higher than control from day 1 to day 4 after exercise (P

  19. Blood flow after contraction and cuff occlusion is reduced in subjects with muscle soreness after eccentric exercise

    DEFF Research Database (Denmark)

    Souza-Silva, Eduardo; Wittrup Christensen, Steffan; Hirata, Rogerio Pessoto

    2017-01-01

    Purpose: Delayed onset muscle soreness (DOMS) occur within 1-2 days after eccentric exercise but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result ...... that eccentric contractions decreased vessel diameter, impaired the blood flow response and promoted hyperalgesia. Thus, the results suggest that the blood flow reduction may be involved in the increased pain response after eccentric exercise....

  20. Protein hydrolysates and recovery of muscle damage following eccentric exercise

    Directory of Open Access Journals (Sweden)

    Dale M.J.

    2015-01-01

    Full Text Available Background: A whey protein hydrolysate (NatraBoost XR; WPHNB has been shown to speed repair muscle damage. We sought to determine whether this benefit is specific to this hydrolysate to evaluate a marker for quality control. Methods: Three hydrolysates of the same whey protein isolate (WPI were prepared (WPHNB, WPH1 and WPH2. Isometric knee extensor strength was measured in 39 sedentary male participants before and after 100 maximal eccentric contractions of the knee extensors to induce muscle damage. Participants were then randomised to consume 250 ml of flavoured water (FW, n=9, or 250 ml of FW containing 25 g of either NatraBoost XR (n=3, WPH1 (n=9, WPH2 (n=9 or WPI (n=9. Strength was reassessed over the next seven days while the supplements were consumed daily. Fibroblasts were cultured for 48 hr in the presence of the different hydrolysates, WPI, saline or fetal bovine serum to ascertain effects on cell proliferation. Results: Strength was reduced in all treatment groups after eccentric exercise (P<0.001. Strength recovered steadily over 7 days in the FW, WPI, WPH1 and WPH2 treatment groups (P<0.001, with no difference between treatments (P=0.87. WPHNB promoted faster strength recovery compared with the other treatments (P<0.001. Fibroblast proliferation was greater with WPHNB compared with saline, WPI or the other hydrolysates (P<0.001. Conclusions: Promoting recovery from muscle damage seems unique to WPHNB. In vitro fibroblast proliferation may be a useful marker for quality control. It is not clear whether effects on fibroblast proliferation contribute to the in vivo effect of WPHNB on muscle damage.

  1. Cosmological Perturbations in Conformal Gravity

    CERN Document Server

    Mannheim, Philip D

    2011-01-01

    We present the first steps needed for an analysis of the perturbations that occur in the cosmology associated with the conformal gravity theory. We discuss the implications of conformal invariance for perturbative coordinate gauge choices, and show that in the conformal theory the trace of the metric fluctuation kinematically decouples from the first-order gravitational fluctuation equations. We determine the equations that describe first-order metric fluctuations around the illustrative conformally flat de Sitter background. Via a conformal transformation we show that such fluctuations can be constructed from fluctuations around a flat background, even though the fluctuations themselves are associated with a perturbative geometry that is not itself conformal to flat. We extend the analysis to fluctuations around other cosmologically relevant backgrounds, such as the conformally-flat Robertson-Walker background, and find tensor fluctuations that grow far more rapidly than those that occur in the analogous sta...

  2. Historical developments in singular perturbations

    CERN Document Server

    O'Malley, Robert E

    2014-01-01

    This engaging text describes the development of singular perturbations, including its history, accumulating literature, and its current status. While the approach of the text is sophisticated, the literature is accessible to a broad audience. A particularly valuable bonus are the historical remarks. These remarks are found throughout the manuscript. They demonstrate the growth of mathematical thinking on this topic by engineers and mathematicians. The book focuses on detailing how the various methods are to be applied. These are illustrated by a  number and variety of examples. Readers are expected to have a working knowledge of elementary ordinary differential equations, including some familiarity with power series techniques, and of some advanced calculus. Dr. O'Malley  has written a number of books on singular perturbations.  This book has developed from many of his works in the field of perturbation theory.

  3. Logarithmic perturbation theory: Applications and limitations | Ndefru ...

    African Journals Online (AJOL)

    The time independent, non-degenerate standard perturbation theory is compared the alternate treatment of perturbation theory called logarithmic perturbation theory (LPT). For determining the non-degenerate ground state the LPT is, in principle, easier to apply than standard perturbation theory. This is because, as ...

  4. Entanglement entropy: a perturbative calculation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenhaus, Vladimir; Smolkin, Michael [Center for Theoretical Physics and Department of Physics,University of California, Berkeley, CA 94720 (United States)

    2014-12-31

    We provide a framework for a perturbative evaluation of the reduced density matrix. The method is based on a path integral in the analytically continued spacetime. It suggests an alternative to the holographic and ‘standard’ replica trick calculations of entanglement entropy. We implement this method within solvable field theory examples to evaluate leading order corrections induced by small perturbations in the geometry of the background and entangling surface. Our findings are in accord with Solodukhin’s formula for the universal term of entanglement entropy for four dimensional CFTs.

  5. Efficient optimization of perturbative gadgets

    OpenAIRE

    Cao, Yudong; Kais, Sabre

    2017-01-01

    Perturbative gadgets are general techniques for reducing many-body spin interactions to two-body ones using perturbation theory. This allows for potential realization of effective many-body interactions using more physically viable two-body ones. In parallel with prior work (arXiv:1311.2555 [quant-ph]), here we consider minimizing the physical resource required for implementing the gadgets initially proposed by Kempe, Kitaev and Regev (arXiv:quant-ph/0406180) and later generalized by Jordan a...

  6. Cosmological perturbation theory and quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Romeo [Dipartimento di Matematica, Università di Trento,Via Sommarive 14, 38123 Povo TN (Italy); Fredenhagen, Klaus [II Institute für Theoretische Physik, Universität Hamburg,Luruper Chaussee 149, 22761 Hamburg (Germany); Hack, Thomas-Paul [Institute für Theoretische Physik, Universität Leipzig,Brüderstr. 16, 04103 Leipzig (Germany); Pinamonti, Nicola [Dipartimento di Matematica, Università di Genova,Via Dodecaneso 35, 16146 Genova (Italy); INFN, Sezione di Genova,Via Dodecaneso 33, 16146 Genova (Italy); Rejzner, Katarzyna [Department of Mathematics, University of York,Heslington, York YO10 5DD (United Kingdom)

    2016-08-04

    It is shown how cosmological perturbation theory arises from a fully quantized perturbative theory of quantum gravity. Central for the derivation is a non-perturbative concept of gauge-invariant local observables by means of which perturbative invariant expressions of arbitrary order are generated. In particular, in the linearised theory, first order gauge-invariant observables familiar from cosmological perturbation theory are recovered. Explicit expressions of second order quantities are presented as well.

  7. Cosmological perturbation theory and quantum gravity

    CERN Document Server

    Brunetti, Romeo; Hack, Thomas-Paul; Pinamonti, Nicola; Rejzner, Katarzyna

    2016-01-01

    It is shown how cosmological perturbation theory arises from a fully quantized perturbative theory of quantum gravity. Central for the derivation is a non-perturbative concept of gauge-invariant local observables by means of which perturbative invariant expressions of arbitrary order are generated. In particular, in the linearised theory, first order gauge-invariant observables familiar from cosmological perturbation theory are recovered. Explicit expressions of second order quantities are presented as well.

  8. Decrease in eccentric quadriceps and hamstring strength in recreational alpine skiers after prolonged skiing.

    Science.gov (United States)

    Koller, Arnold; Fuchs, Birgit; Leichtfried, Veronika; Schobersberger, Wolfgang

    2015-01-01

    To effectively prevent injury in recreational alpine skiing, it is important to identify modifiable risk factors that can be targeted through exercise and training. Fatigue is a potential risk factor in recreational skiing, but no investigations have evaluated concentric/eccentric quadriceps and hamstring fatigue in recreational skiers. We tested the hypothesis that recreational skiing is associated with more pronounced eccentric as compared with concentric muscle fatigue. Twenty-four healthy and fit recreational skiers (14 male and 10 female) performed an isokinetic muscle test 1 day before, 1 h after, and 24 h after a 4 h skiing session. The testing protocol consisted of concentric and eccentric quadriceps and hamstring contractions for both legs. Eccentric peak hamstring torque (both thighs) and eccentric peak quadriceps torque (left thigh) were reduced in male and female participants (pfatigue in men and women. Eccentric quadriceps and hamstring fatigue may be a potential injury risk factor in male and female recreational skiers. This provides some justification for judicious use of additional eccentric training modalities for alpine skiing.

  9. Eccentrically mounted rotor pack and its influence on the vibration and noise of an asynchronous generator

    Science.gov (United States)

    Donát, Martin; Dušek, Daniel

    2015-05-01

    Time-varying magnetic forces are the main source of vibrations in rotating electrical machines. A number of papers dealing with computational modelling of the dynamic behaviour of rotating electrical machines have been published. Almost all of these papers do not consider electro-mechanical interaction between the stator and the rotor of the machine. A computational model including electro-mechanical interaction is proposed in this paper. The influence of the air gap eccentricity due to eccentric mounting of the rotor pack on the shaft of the rotor is investigated. Electromagnetic coupled-field analysis was performed to obtain the dependence of the magnetic forces, which act on the stator and the rotor pack, on the time and air gap eccentricity. Attention has been paid to the air gap eccentricity due to the interaction between the stator and the rotor and the influence of the air gap eccentricity on the vibration and sound power of the machine. The obtained results show that the air gap eccentricity affects the amplitude spectrum of the magnetic forces. This change of amplitude spectrum causes a significant increase in the torsional vibration of the stator of the examined machine. The air gap eccentricity is also significantly reflected in the trajectory of the rotor centre line and radial load of bearings in the machine.

  10. The effect of face eccentricity on the perception of gaze direction.

    Science.gov (United States)

    Todorović, Dejan

    2009-01-01

    The perception of a looker's gaze direction depends not only on iris eccentricity (the position of the looker's irises within the sclera) but also on the orientation of the lookers' head. One among several potential cues of head orientation is face eccentricity, the position of the inner features of the face (eyes, nose, mouth) within the head contour, as viewed by the observer. For natural faces this cue is confounded with many other head-orientation cues, but in schematic faces it can be studied in isolation. Salient novel illustrations of the effectiveness of face eccentricity are 'Necker faces', which involve equal iris eccentricities but multiple perceived gaze directions. In four experiments, iris and face eccentricity in schematic faces were manipulated, revealing strong and consistent effects of face eccentricity on perceived gaze direction, with different types of tasks. An additional experiment confirmed the 'Mona Lisa' effect with this type of stimuli. Face eccentricity most likely acted as a simple but robust cue of head turn. A simple computational account of combined effects of cues of eye and head turn on perceived gaze direction is presented, including a formal condition for the perception of direct gaze. An account of the 'Mona Lisa' effect is presented.

  11. Eccentric Training for Tendon Healing After Acute Lesion: A Rat Model.

    Science.gov (United States)

    Kaux, Jean-François; Libertiaux, Vincent; Leprince, Pierre; Fillet, Marianne; Denoel, Vincent; Wyss, Clémence; Lecut, Christelle; Gothot, André; Le Goff, Caroline; Croisier, Jean-Louis; Crielaard, Jean-Michel; Drion, Pierre

    2017-05-01

    The tendon is a dynamic entity that remodels permanently. Platelet-rich plasma (PRP) injection has been shown to have a beneficial effect on tendon healing after lesion in rats. Furthermore, eccentric exercise seems to improve the mechanical quality of the tendon. A combination of PRP injection and eccentric training might be more effective than either treatment alone. Controlled laboratory study. Adult male rats were anesthetized, an incision was performed in the middle of their left patellar tendon and an injection of physiological fluid (PF) or homologous PRP was randomly made at the lesion level. The rats were then divided into 2 groups: the eccentric group, undergoing eccentric training 3 times a week, and the untrained group, without any training. Thus, 4 groups were compared. After 5 weeks, the tendons were removed and their ultimate tensile strength and energy were measured. Tendons were frozen for proteomic analyses when all biomechanical tests were completed. Statistical analysis was performed with linear mixed effect models. No significant difference was found between the treatments using PF injection or PRP injection alone. However, the value of the ultimate tensile force at rupture was increased by 4.5 N (108% of control, P = .006) when eccentric training was performed. An intragroup analysis revealed that eccentric training significantly improved the ultimate force values for the PRP group. Proteomic analysis revealed that eccentric training led to an increase in abundance of several cytoskeletal proteins in the PF group, while a decrease in abundance of enzymes of the glycolytic pathway occurred in the PRP-treated groups, indicating that this treatment might redirect the exercise-driven metabolic plasticity of the tendon. Eccentric training altered the metabolic plasticity of tendon and led to an improvement of injured tendon resistance regardless of the treatment injected (PF or PRP). This study demonstrates the necessity of eccentric rehabilitation

  12. The Effect of Taurine on the Recovery from Eccentric Exercise-Induced Muscle Damage in Males

    Directory of Open Access Journals (Sweden)

    Yanita McLeay

    2017-10-01

    Full Text Available Eccentric exercise is known to bring about microstructural damage to muscle, initiating an inflammatory cascade involving various reactive oxygen species. This, in turn, can significantly impair physical performance over subsequent days. Taurine, a powerful endogenous antioxidant, has previously been shown to have a beneficial effect on muscle damage markers and recovery when taken for a few days to several weeks prior to eccentric exercise. However, to date no studies have looked at the effects of supplementing over the days following eccentric exercise on performance recovery. Thus, this study aimed to determine whether supplementing with taurine over three days following eccentric exercise attenuated the rise in serum creatine kinase and improved performance recovery in males. In a blinded, randomized, crossover design, ten recreationally-fit male participants completed 60 eccentric contractions of the biceps brachii muscle at maximal effort. Following this, participants were supplemented with 0.1 g∙kg−1 body weight∙day−1 of either taurine or rice flour in capsules. Over the next three mornings participants underwent blood tests for the analysis of the muscle damage marker creatine kinase and carried out performance measures on the isokinetic dynamometer. They also continued to consume the capsules in the morning and evening. The entire protocol was repeated two weeks later on the alternate arm and supplement. Significant decreases were seen in all performance measures from pre- to 24-h post-eccentric exercise (p < 0.001 for both taurine and placebo, indicating the attainment of muscle damage. Significant treatment effects were observed only for peak eccentric torque (p < 0.05. No significant time × treatment effects were observed (all p > 0.05. Serum creatine kinase levels did not significantly differ over time for either treatments, nor between treatments (p > 0.05. These findings suggest that taurine supplementation taken twice

  13. The Effect of Estrogen Usage on Eccentric Exercise-Induced Damage in Rat Testes

    Science.gov (United States)

    Can, Serpil; Selli, Jale; Buyuk, Basak; Aydin, Sergulen; Kocaaslan, Ramazan; Guvendi, Gulname Findik

    2015-01-01

    Background: Recent years, lots of scientific studies are focused on the possible mechanism of inflammatory response and oxidative stress which are the mechanism related with tissue damage and exercise fatigue. It is well-known that free oxygen radicals may be induced under invitro conditions as well as oxidative stress by exhaustive physical exercise. Objectives: The aim of this study was to investigate the effects of anabolic steroids in conjunction with exercise in the process of spermatogenesis in the testes, using histological and stereological methods. Materials and Methods: Thirty-six male Sprague Dawley rats were divided to six groups, including the control group, the eccentric exercise administered group, the estrogen applied group, the estrogen applied and dissected one hour after eccentric exercise group, the no estrogen applied and dissected 48 hours after eccentric exercise group and the estrogen applied and dissected 48 hours after eccentric exercise group. Eccentric exercise was performed on a motorized rodent treadmill and the estrogen applied groups received daily physiological doses by subcutaneous injections. Testicular tissues were examined using specific histopathological, immunohistochemical and stereological methods. Sections of the testes tissue were stained using the TUNEL method to identify apoptotic cells. Apoptosis was calculated as the percentage of positive cells, using stereological analysis. A statistical analysis of the data was carried out with one-way analysis of variance (ANOVA) for the data obtained from stereological analysis. Results: Conventional light microscopic results revealed that testes tissues of the eccentric exercise administered group and the estrogen supplemented group exhibited slight impairment. In groups that were both eccentrically exercised and estrogen supplemented, more deterioration was detected in testes tissues. Likewise, immunohistochemistry findings were also more prominent in the eccentrically exercised

  14. THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. I. MEASURING PHOTOMETRIC ECCENTRICITIES OF INDIVIDUAL TRANSITING PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Rebekah I. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States); Johnson, John Asher, E-mail: rdawson@cfa.harvard.edu [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States)

    2012-09-10

    Exoplanet orbital eccentricities offer valuable clues about the history of planetary systems. Eccentric, Jupiter-sized planets are particularly interesting: they may link the 'cold' Jupiters beyond the ice line to close-in hot Jupiters, which are unlikely to have formed in situ. To date, eccentricities of individual transiting planets primarily come from radial-velocity measurements. Kepler has discovered hundreds of transiting Jupiters spanning a range of periods, but the faintness of the host stars precludes radial-velocity follow-up of most. Here, we demonstrate a Bayesian method of measuring an individual planet's eccentricity solely from its transit light curve using prior knowledge of its host star's density. We show that eccentric Jupiters are readily identified by their short ingress/egress/total transit durations-part of the 'photoeccentric' light curve signature of a planet's eccentricity-even with long-cadence Kepler photometry and loosely constrained stellar parameters. A Markov Chain Monte Carlo exploration of parameter posteriors naturally marginalizes over the periapse angle and automatically accounts for the transit probability. To demonstrate, we use three published transit light curves of HD 17156 b to measure an eccentricity of e = 0.71{sup +0.16}{sub -0.09}, in good agreement with the discovery value e = 0.67 {+-} 0.08 based on 33 radial-velocity measurements. We present two additional tests using Kepler data. In each case, the technique proves to be a viable method of measuring exoplanet eccentricities and their confidence intervals. Finally, we argue that this method is the most efficient, effective means of identifying the extremely eccentric, proto-hot Jupiters predicted by Socrates et al.

  15. Review of chiral perturbation theory

    Indian Academy of Sciences (India)

    the CLEO Collaboration. Other sources could be the decay τ →ππν. In the modern context, a fresh Roy equation analysis with the view of combining dis- persion relations with chiral perturbation theory has been carried out [20]. The evaluation of the inhomogeneous terms, the so-called 'driving terms' for the Roy equations ...

  16. Disformal invariance of curvature perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Motohashi, Hayato [Kavli Institute for Cosmological Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois, 60637 (United States); White, Jonathan, E-mail: motohashi@kicp.uchicago.edu, E-mail: jwhite@post.kek.jp [Research Center for the Early Universe (RESCEU), The University of Tokyo, Hongo 7-3-1, Tokyo, 113-0033 Japan (Japan)

    2016-02-01

    We show that under a general disformal transformation the linear comoving curvature perturbation is not identically invariant, but is invariant on superhorizon scales for any theory that is disformally related to Horndeski's theory. The difference between disformally related curvature perturbations is found to be given in terms of the comoving density perturbation associated with a single canonical scalar field. In General Relativity it is well-known that this quantity vanishes on superhorizon scales through the Poisson equation that is obtained on combining the Hamiltonian and momentum constraints, and we confirm that a similar result holds for any theory that is disformally related to Horndeski's scalar-tensor theory so long as the invertibility condition for the disformal transformation is satisfied. We also consider the curvature perturbation at full nonlinear order in the unitary gauge, and find that it is invariant under a general disformal transformation if we assume that an attractor regime has been reached. Finally, we also discuss the counting of degrees of freedom in theories disformally related to Horndeski's.

  17. VHS Movies: Perturbations for Morphogenesis.

    Science.gov (United States)

    Holmes, Danny L.

    This paper discusses the concept of a family system in terms of an interactive system of interrelated, interdependent parts and suggests that VHS movies can act as perturbations, i.e., change promoting agents, for certain dysfunctional family systems. Several distinct characteristics of a family system are defined with particular emphasis on…

  18. Seven topics in perturbative QCD

    Energy Technology Data Exchange (ETDEWEB)

    Buras, A.J.

    1980-09-01

    The following topics of perturbative QCD are discussed: (1) deep inelastic scattering; (2) higher order corrections to e/sup +/e/sup -/ annihilation, to photon structure functions and to quarkonia decays; (3) higher order corrections to fragmentation functions and to various semi-inclusive processes; (4) higher twist contributions; (5) exclusive processes; (6) transverse momentum effects; (7) jet and photon physics.

  19. Basics of QCD perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Soper, D.E. [Univ. of Oregon, Eugene, OR (United States). Inst. of Theoretical Science

    1997-06-01

    This is an introduction to the use of QCD perturbation theory, emphasizing generic features of the theory that enable one to separate short-time and long-time effects. The author also covers some important classes of applications: electron-positron annihilation to hadrons, deeply inelastic scattering, and hard processes in hadron-hadron collisions. 31 refs., 38 figs.

  20. Eccentric exercise facilitates mesenchymal stem cell appearance in skeletal muscle.

    Directory of Open Access Journals (Sweden)

    M Carmen Valero

    Full Text Available Eccentric, or lengthening, contractions result in injury and subsequently stimulate the activation and proliferation of satellite stem cells which are important for skeletal muscle regeneration. The discovery of alternative myogenic progenitors in skeletal muscle raises the question as to whether stem cells other than satellite cells accumulate in muscle in response to exercise and contribute to post-exercise repair and/or growth. In this study, stem cell antigen-1 (Sca-1 positive, non-hematopoetic (CD45⁻ cells were evaluated in wild type (WT and α7 integrin transgenic (α7Tg mouse muscle, which is resistant to injury yet liable to strain, 24 hr following a single bout of eccentric exercise. Sca-1⁺CD45⁻ stem cells were increased 2-fold in WT muscle post-exercise. The α7 integrin regulated the presence of Sca-1⁺ cells, with expansion occurring in α7Tg muscle and minimal cells present in muscle lacking the α7 integrin. Sca-1⁺CD45⁻ cells isolated from α7Tg muscle following exercise were characterized as mesenchymal-like stem cells (mMSCs, predominantly pericytes. In vitro multiaxial strain upregulated mMSC stem cells markers in the presence of laminin, but not gelatin, identifying a potential mechanistic basis for the accumulation of these cells in muscle following exercise. Transplantation of DiI-labeled mMSCs into WT muscle increased Pax7⁺ cells and facilitated formation of eMHC⁺DiI⁻ fibers. This study provides the first demonstration that mMSCs rapidly appear in skeletal muscle in an α7 integrin dependent manner post-exercise, revealing an early event that may be necessary for effective repair and/or growth following exercise. The results from this study also support a role for the α7 integrin and/or mMSCs in molecular- and cellular-based therapeutic strategies that can effectively combat disuse muscle atrophy.

  1. Effect of an eccentric rotation on the equilibrium shapes and stability of liquid bridges in a lateral gravity field

    Science.gov (United States)

    Laverón-Simavilla, Ana; Lapuerta, Victoria; Rodríguez, Angel; Perales, Jose Manuel

    A cylindrical liquid bridge supported between two circular-shaped disks in isorotation is considered. The combined effect of a lateral gravity field and an offset between the rotation axis and the axis of the supporting disks (eccentricity) on the stability of the liquid bridge is here studied. In a previous work a numerical method used to determine the stability limit for different values of eccentricity was validated by comparing with analytical results at small eccentricity. In this work we use an extension of that algorithm applied to liquid bridges in a lateral gravitational field rotating around an eccentric axis to study the combined effect of rotation, eccentricity and lateral gravity. The analysis shows that the combined effect of lateral gravity and eccentricity can narrow or broaden the stability region depending on the angle between the gravity direction and the eccentric axis displacement.

  2. Perturbative and Non-perturbative $N=8$ Supergravity

    CERN Document Server

    Bianchi, Massimo; Kallosh, Renata

    2010-01-01

    We study extremal black holes, their ADM mass and area of the horizon in N = 8 supergravity. Contrary to intuition gained from N = 2, 4 theories, in N = 8 supergravity BPS states may become massless only at the boundary of moduli space. We show that stringy states described in [1], which have no mass gap and survive in the toroidal compactification in addition to massless states of perturbative N = 8 supergravity, display a null singularity in four-dimensional space-time, when viewed as solutions of N = 8 Einstein equations. We analyze known methods of resolving such singularities and explain why they do not work in D=4, N = 8 supergravity. We discuss possible implications for the issue of UV finiteness of the four-dimensional N = 8 perturbation theory.

  3. Eccentric utilization ratio: effect of sport and phase of training.

    Science.gov (United States)

    McGuigan, Michael R; Doyle, Timothy L A; Newton, Michael; Edwards, Dylan J; Nimphius, Sophia; Newton, Robert U

    2006-11-01

    The eccentric utilization ratio (EUR), which is the ratio of countermovement jump (CMJ) to static jump (SJ) performance, has been suggested as a useful indicator of power performance in athletes. The purpose of the study was to compare the EUR of athletes from a variety of different sports and during different phases of training. A total of 142 athletes from rugby union, Australian Rules Football, soccer, softball, and field hockey were tested. Subjects performed both CMJ and SJ on a force plate integrated with a position transducer. The EUR was measured as the ratio of CMJ to SJ for jump height and peak power. The rugby union, Australian Rules Football, and hockey athletes were tested during off-season and preseason to provide EUR data during different phases of training. For men, EUR for soccer, Australian Rules Football, and rugby was greater than softball (effect size range, 0.83-0.92). For women, EUR for soccer was greater than field hockey and softball (0.86- 1.0). There was a significant difference between the jump height and peak power method for the Australian Rules Football, rugby, and field hockey tests conducted preseason (p training with the values significantly increasing from off-season to preseason. The EUR provides the practitioner with information about the performance of athletes and appears to be sensitive to changes in the type of training being undertaken.

  4. A study of eccentric viewing training for low vision rehabilitation.

    Science.gov (United States)

    Jeong, Jae Hoon; Moon, Nam Ju

    2011-12-01

    The definition of eccentric viewing (EV) is using non-foveal preferred retinal loci (PRL) for viewing. The purpose of the present study was to investigate the clinical effect of EV training for low vision rehabilitation in patients with central scotomas. The direction of EV was monitored in 30 low vision patients with central scotomas by moving the patient's view. The PRL was found by using a direct ophthalmoscope and retinal camera; the preserved visual field was identified using a kinetic visual field analyzer. The relationships between EV, PRL, and visual field were evaluated. The patients and their guardians were educated regarding EV. After 2 weeks of self-training, maintenance of EV was checked and changes in best-corrected visual acuity (BCVA), reading speed, and satisfaction questionnaire were evaluated. A relationship between EV, PRL, and visual field was in accordance in half of the patients. There were no significant differences in demographics and basic visual characteristics in patients where the relationship was not in accordance. EV was maintained in two-thirds of the patients, but there were no significant differences in demographics and basic visual characteristics in patients who discontinued EV. There were no significant improvements in BCVA; however, reading speed and the satisfaction scores increased significantly with EV. The direction of EV was effectively detected by convenient access using an inexpensive method. Functional vision and satisfaction significantly improved following EV training. EV training can be used as an effective method for low vision rehabilitation in patients with central scotomas.

  5. Dyadic Green's function of an eccentrically stratified sphere.

    Science.gov (United States)

    Moneda, Angela P; Chrissoulidis, Dimitrios P

    2014-03-01

    The electric dyadic Green's function (dGf) of an eccentrically stratified sphere is built by use of the superposition principle, dyadic algebra, and the addition theorem of vector spherical harmonics. The end result of the analytical formulation is a set of linear equations for the unknown vector wave amplitudes of the dGf. The unknowns are calculated by truncation of the infinite sums and matrix inversion. The theory is exact, as no simplifying assumptions are required in any one of the analytical steps leading to the dGf, and it is general in the sense that any number, position, size, and electrical properties can be considered for the layers of the sphere. The point source can be placed outside of or in any lossless part of the sphere. Energy conservation, reciprocity, and other checks verify that the dGf is correct. A numerical application is made to a stratified sphere made of gold and glass, which operates as a lens.

  6. Effects of fast-velocity eccentric resistance training on early and late rate of force development

    DEFF Research Database (Denmark)

    Oliveira, Anderson S.C.; Corvino, Rogério Bulhões; Caputo, Fabrizio

    2016-01-01

    This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (100 ms) of rising torque. Twenty healthy men were...... assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC......, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL...

  7. Neural and morphological adaptations of vastus lateralis and vastus medialis muscles to isokinetic eccentric training

    Directory of Open Access Journals (Sweden)

    Rodrigo de Azevedo Franke

    2014-09-01

    Full Text Available Vastus lateralis (VL and vastus medialis (VM are frequently targeted in conditioning/rehabilitation programs due to their role in patellar stabilization during knee extension. This study assessed neural and muscular adaptations in these two muscles after an isokinetic eccentric training program. Twenty healthy men underwent a four-week control period followed by a 12-week period of isokinetic eccentric training. Ultrasound evaluations of VL and VM muscle thickness at rest and electromyographic evaluations during maximal isometric tests were used to assess the morphological and neural properties, respectively. No morphological and neural changes were found throughout the control period, whereas both muscles showed significant increases in thickness (VL = 6.9%; p .05 post-training. Isokinetic eccentric training produces neural and greater morphological adaptations in VM compared to VL, which shows that synergistic muscles respond differently to an eccentric isokinetic strength training program

  8. Effects of kinesio taping on anaerobic power recovery after eccentric exercise.

    Science.gov (United States)

    Szymura, Jadwiga; Maciejczyk, Marcin; Wiecek, Magdalena; Maciejczyk, Grzegorz; Wiecha, Szczepan; Ochalek, Katarzyna; Kepinska, Magdalena; Szygula, Zbigniew

    2016-01-01

    The aim of the study was to evaluate the effectiveness of kinesio taping (KT) in anaerobic power recovery after eccentric exercise. The study was carried out on 10 healthy men. The participants performed two 60-min downhill runs with a constant intensity. Peak anaerobic power (PP) and mean power (MP) were measured before and five times after eccentric exercise. Anaerobic power was evaluated with the Maximal Cycling Sprint Test. After the downhill run, passive recovery (PR) and KT (lymphatic application) were applied in random order. A significant decrease in PP and MP was observed at least for 24 h after PR, compared to baseline. After the KT application 24 h after eccentric exercises, anaerobic power was already similar to the baseline measurement. The application of KT significantly improved anaerobic power recovery time after eccentric exercise compared to the period of passive rest immediately prior to testing.

  9. Contralateral Repeated Bout Effect of Eccentric Exercise of the Elbow Flexors

    National Research Council Canada - National Science Library

    Chen, TREVOR C; CHEN, HSIN-LIAN; LIN, MING-JU; YU, HUI-I; NOSAKA, KAZUNORI

    2016-01-01

    PURPOSEThis study compared the magnitude of the repeated bout effect (RBE) for different time intervals between two bouts of eccentric exercise of the elbow flexors to better understand the contralateral RBE (CL-RBE...

  10. Gravitational-wave phasing for low-eccentricity inspiralling compact binaries to 3PN order

    CERN Document Server

    Moore, Blake; Arun, K G; Mishra, Chandra Kant

    2016-01-01

    [abridged] Although gravitational radiation causes inspiralling compact binaries to circularize, a variety of astrophysical scenarios suggest that binaries might have small but nonnegligible orbital eccentricities when they enter the low-frequency bands of ground and space-based gravitational-wave detectors. If not accounted for, even a small orbital eccentricity can cause a potentially significant systematic error in the mass parameters of an inspiralling binary. Gravitational-wave search templates typically rely on the quasi-circular approximation, which provides relatively simple expressions for the gravitational-wave phase to 3.5 post-Newtonian (PN) order. The quasi-Keplerian formalism provides an elegant but complex description of the post-Newtonian corrections to the orbits and waveforms of inspiralling binaries with any eccentricity. Here we specialize the quasi-Keplerian formalism to binaries with low eccentricity. In this limit the non-periodic contribution to the gravitational-wave phasing can be ex...

  11. Effects of an eccentric training programme on hamstring strain injuries in women football players

    Directory of Open Access Journals (Sweden)

    del Ama Espinosa Gurutze

    2015-09-01

    Full Text Available Study aim: to test the hypothesis that an eccentric training programme applied on women football players would reduce the hamstring injury rate by improving thigh muscle balance and, particularly, hamstring strength.

  12. Aortic stenosis with abnormal eccentric left ventricular remodeling secondary to hypothyroidism in a Bourdeaux Mastiff

    Directory of Open Access Journals (Sweden)

    Guilherme Augusto Minozzo

    Full Text Available ABSTRACT: This paper describes a case of congenital aortic stenosis with eccentric left ventricular hypertrophy associated with hypothyroidism in a 1-year-old Bourdeaux Mastiff dog. The dog had ascites, apathy, alopecic and erythematous skin lesions in different parts of the body. A two-dimensional echocardiogram revealed aortic valve stenosis, with poststenotic dilation in the ascending aorta. The same exam showed eccentric hypertrophy and dilation of the left ventricle during systole and diastole. Aortic stenosis usually results in concentric left ventricular hypertrophy instead of eccentric hypertrophy; and therefore, this finding was very unusual. Hypothyroidism, which is uncommon in young dogs, may be incriminated as the cause of ventricular dilation, making this report even more interesting. Because hypothyroidism would only result in dilatation, the eccentric hypertrophy was attributed to pressure overload caused by aortic stenosis. Thus, cardiac alterations of this case represent a paradoxical association of both diseases.

  13. The role of eccentric regime of leg muscle work in alpine skiing

    Directory of Open Access Journals (Sweden)

    Ropret Robert

    2017-01-01

    Full Text Available Alpine skiing is characterized by a great number of leg movements with muscle contractions in eccentric regime. The role of these movements is to absorb gravitation and inertial forces, manage skis more precisely and maintain balance. Recent studies have determined the volume, duration and intenisty of eccentric contractions as well as the basic characteristics of movement amplitudes and velocities. Based on the previous findings the experiments involving eccentric training using a bicycle ergometer confirmed a positive impact that this kind of training has on increasing maximum power, strength, endurance, coordination, injury prevention, metabolic work efficiency, more efficient work with longer muscle length and its role in miming skiers' movements. This paper is an review of the studies so far in the field of kinematics, skiing dynamics and the effect of eccentric training on the development of athletes' performances.

  14. Detection of Eccentricity Faults in Five-Phase Ferrite-PM Assisted Synchronous Reluctance Machines

    National Research Council Canada - National Science Library

    Carlos López-Torres; Jordi-Roger Riba; Antonio Garcia; Luís Romeral

    2017-01-01

    ... (zero-sequence voltage component). However, there is a lack of research dealing with the topic of fault diagnosis in multi-phase PMa-SynRMs, and in particular, those focused on detecting eccentricity faults...

  15. Effect of load eccentricity and stress level on monopile support for offshore wind turbines

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Hededal, Ole

    2014-01-01

    on which load is applied with a large eccentricity. With centrifuge tests as the basis, this paper investigates the behaviour of a rigid pile loaded with a high eccentricity. A test series was carried out to simulate idealized monotonic load cases for monopiles supporting an offshore wind turbine....... Centrifuge tests were performed on model monopiles subjected to stress distributions equal to prototype monopiles with pile diameters ranging from 1–5 m and eccentricities ranging from 8.25–17.75 pile diameters. It was possible to identify a unified response of all of these tests by using dimensional...... analysis and Rankine’s passive earth pressure coefficient as a normalization parameter. The normalized ultimate soil resistance was unaffected by acceleration level and load eccentricity, indicating that the failure mechanism was the same for all tests. Based on the centrifuge tests, a reformulation...

  16. BRST quantization of cosmological perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Armendariz-Picon, Cristian [Physics Department, St. Lawrence University,Canton, NY 13617 (United States); Şengör, Gizem [Department of Physics, Syracuse University,Syracuse, NY 13244 (United States)

    2016-11-08

    BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely related quantization method of Dirac. We describe how both formalisms apply to perturbations in a time-dependent background, and how expectation values of gauge-invariant operators can be calculated in the in-in formalism. Our analysis focuses mostly on the free theory. By appropriate canonical transformations we simplify and diagonalize the free Hamiltonian. BRST quantization in derivative gauges allows us to dramatically simplify the structure of the propagators, whereas Dirac quantization, which amounts to quantization in synchronous gauge, dispenses with the need to introduce ghosts and preserves the locality of the gauge-fixed action.

  17. Effect of sport massage on pressure pain threshold and tolerance in athletes under eccentric exercise

    Directory of Open Access Journals (Sweden)

    Abdullah Selim KAPLAN

    2014-08-01

    Full Text Available Extensive line of evidence suggest that pain threshold and tolerance alters following exercise, although the mechanisms have not been elucidated yet. In this st udy, we investigated the role of sport massage on pressure pain threshold and tolerance in athletes under eccentric exercise. Ten male athletes aged 23 ± 1 years with 9.67 ± 3.04 years of athletic training were recruited for this study . Following baseline measurements of pressure pain threshold and tolerance from m. biceps brachii and m. triceps brachii muscle and myofascial regions of the dominant upper extremity by using a digital algometer, subjects were underwent an acute bout of eccentric exercise. Par ticipants were completed 4 sets of eccentric exercise each comprising 20 repetitions of lifting 80% of their 1 RM by using a dumbbell. Pressure pain threshold and tolerance tests were repeated 10, 20 and 30 minutes, and 24 and 48 hours following exercise. One week after eccentric exercise, sport massage protocol for 10 minutes was manually administered to the dominant arm immediately after exercise, and all measurements were repeated at the same timeline as eccentric exercise. Results are presented as mean + standart deviation. Data of the same timeline were analyzed by using t test. A level of p<0.05 was accepted statistical significant. Eccentric exercise resulted to increase the pain tolerance from muscle and myofascia regions of m. biceps and triceps br achii, and sport massage was found to decrease the pain tolerance at 10 minutes from muscle regions of m. biceps and triceps brachii, 10, 20 and 30 minutes from myofascial region of biceps brachii, and 20 minutes, 24 and 48 hours from myofascial region of m. triceps brachii following acute bout of eccentric exercise in athletes. We concluded that sport massage reduces the hypoalgesic response during acute and delayed period of recovery after eccentric exercise.

  18. Neural and morphological adaptations of vastus lateralis and vastus medialis muscles to isokinetic eccentric training

    OpenAIRE

    Franke,Rodrigo de Azevedo; Baroni,Bruno Manfredini; Rodrigues,Rodrigo; Geremia,Jeam Marcel; Lanferdini,Fábio Juner; Vaz,Marco Aurélio

    2014-01-01

    Vastus lateralis (VL) and vastus medialis (VM) are frequently targeted in conditioning/rehabilitation programs due to their role in patellar stabilization during knee extension. This study assessed neural and muscular adaptations in these two muscles after an isokinetic eccentric training program. Twenty healthy men underwent a four-week control period followed by a 12-week period of isokinetic eccentric training. Ultrasound evaluations of VL and VM muscle thickness at rest and electromyograp...

  19. Eccentric Left Ventricular Hypertrophy and Sudden Death in Patients with End-Stage Kidney Disease.

    Science.gov (United States)

    de Roij van Zuijdewijn, Camiel L M; Hansildaar, Romy; Bots, Michiel L; Blankestijn, Peter J; van den Dorpel, Marinus A; Grooteman, Muriel P C; Kamp, Otto; ter Wee, Piet M; Nubé, Menso J

    2015-01-01

    Both all-cause and cardiovascular mortality risks are extremely high in patients with end-stage kidney disease (ESKD). Sudden death accounts for approximately one-quarter of all fatal events. Left ventricular hypertrophy (LVH) is a known risk factor for mortality and can be divided in 2 types: concentric and eccentric. This study evaluated possible differences in all-cause mortality, cardiovascular mortality and sudden death between prevalent ESKD patients with concentric and eccentric LVH. Participants of the CONvective TRAnsport STudy (CONTRAST) who underwent transthoracic echocardiography (TTE) at baseline were analyzed. In patients with LVH, a relative wall thickness of ≤0.42 was considered eccentric and >0.42 was considered concentric hypertrophy. Cox proportional hazards models, adjusted for potential confounders, were used to calculate hazard ratios (HRs) of patients with eccentric LVH versus patients with concentric LVH for all-cause mortality, cardiovascular mortality and sudden death. TTE was performed in 328 CONTRAST participants. LVH was present in 233 participants (71%), of which 87 (37%) had concentric LVH and 146 (63%) eccentric LVH. The HR for all-cause mortality of eccentric versus concentric LVH was 1.14 (p = 0.52), 1.79 (p = 0.12) for cardiovascular mortality and 4.23 (p = 0.02) for sudden death in crude analyses. Propensity score-corrected HR for sudden death in patients with eccentric LVH versus those with concentric LVH was 5.22 (p = 0.03). (1) The hazard for all-cause mortality, cardiovascular mortality and sudden death is markedly increased in patients with LVH. (2) The sudden death risk is significantly higher in ESKD patients with eccentric LVH compared to subjects with concentric LVH. © 2015 S. Karger AG, Basel.

  20. Ultrasound-Guided Percutaneous Electrolysis and Eccentric Exercises for Subacromial Pain Syndrome: A Randomized Clinical Trial

    OpenAIRE

    José L. Arias-Buría; Sebastián Truyols-Domínguez; Raquel Valero-Alcaide; Jaime Salom-Moreno; María A. Atín-Arratibel; César Fernández-de-las-Peñas

    2015-01-01

    Objective. To compare effects of ultrasound- (US-) guided percutaneous electrolysis combined with an eccentric exercise program of the rotator cuff muscles in subacromial pain syndrome. Methods. Thirty-six patients were randomized and assigned into US-guided percutaneous electrolysis (n = 17) group or exercise (n = 19) group. Patients were asked to perform an eccentric exercise program of the rotator cuff muscles twice every day for 4 weeks. Participants assigned to US-guided percutaneous ele...

  1. Cellular mechanism of eccentric-induced muscle injury and its relationship with sarcomere heterogeneity

    OpenAIRE

    Choi, Seung Jun

    2014-01-01

    Activity-induced muscle injury and dysfunction have been identified as key components of musculoskeletal injuries. These injuries often occur following eccentric contractions, when the muscle is under tension and stretched by a force that is greater than the force generated by the muscle. Many daily activities require muscles to perform eccentric contractions, including walking (or running) downhill or down stairs, lowering heavy objects, and landing from a jump. Injuries often occur when the...

  2. The Effect of Taurine on the Recovery from Eccentric Exercise-Induced Muscle Damage in Males.

    Science.gov (United States)

    McLeay, Yanita; Stannard, Stephen; Barnes, Matthew

    2017-10-17

    Eccentric exercise is known to bring about microstructural damage to muscle, initiating an inflammatory cascade involving various reactive oxygen species. This, in turn, can significantly impair physical performance over subsequent days. Taurine, a powerful endogenous antioxidant, has previously been shown to have a beneficial effect on muscle damage markers and recovery when taken for a few days to several weeks prior to eccentric exercise. However, to date no studies have looked at the effects of supplementing over the days following eccentric exercise on performance recovery. Thus, this study aimed to determine whether supplementing with taurine over three days following eccentric exercise attenuated the rise in serum creatine kinase and improved performance recovery in males. In a blinded, randomized, crossover design, ten recreationally-fit male participants completed 60 eccentric contractions of the biceps brachii muscle at maximal effort. Following this, participants were supplemented with 0.1 g∙kg-1 body weight∙day-1 of either taurine or rice flour in capsules. Over the next three mornings participants underwent blood tests for the analysis of the muscle damage marker creatine kinase and carried out performance measures on the isokinetic dynamometer. They also continued to consume the capsules in the morning and evening. The entire protocol was repeated two weeks later on the alternate arm and supplement. Significant decreases were seen in all performance measures from pre- to 24-h post-eccentric exercise (p time × treatment effects were observed (all p > 0.05). Serum creatine kinase levels did not significantly differ over time for either treatments, nor between treatments (p > 0.05). These findings suggest that taurine supplementation taken twice daily for 72 h following eccentric exercise-induced muscle damage may help improve eccentric performance recovery of the biceps brachii.

  3. Enhanced procollagen processing in skeletal muscle after a single bout of eccentric loading in humans

    DEFF Research Database (Denmark)

    Crameri, Regina M; Langberg, Henning; Teisner, Børge

    2004-01-01

    young healthy male subjects performed a single bout of unaccustomed high intensity eccentric exercise on one leg, with the contralateral leg being the control. A significant increase in the muscle interstitial concentration of the N-terminal propeptide of procollagen type I (PINP) was observed (day 0: 1...... mechanical load and inflammation. This study shows that following a single bout of high intensity eccentric exercise there is an increase in procollagen processing within skeletal muscle in humans....

  4. Perturbative gadgets without strong interactions

    OpenAIRE

    Cao, Yudong; Nagaj, Daniel

    2014-01-01

    Perturbative gadgets are used to construct a quantum Hamiltonian whose low-energy subspace approximates a given quantum $k$-body Hamiltonian up to an absolute error $\\epsilon$. Typically, gadget constructions involve terms with large interaction strengths of order $\\text{poly}(\\epsilon^{-1})$. Here we present a 2-body gadget construction and prove that it approximates a target many-body Hamiltonian of interaction strength $\\gamma = O(1)$ up to absolute error $\\epsilon\\ll\\gamma$ using interact...

  5. Influence of Wheel Eccentricity on Vertical Vibration of Suspended Monorail Vehicle: Experiment and Simulation

    Directory of Open Access Journals (Sweden)

    Kaikai Lv

    2017-01-01

    Full Text Available This paper investigates the influence of wheel eccentricity on vertical vibration of suspended monorail vehicle based on experiment and simulation. Two sets of tests are conducted in the first Chinese suspended monorail, and the tested acceleration is analyzed and exhibited. A multibody dynamic model of the suspended monorail vehicle is established to simulate the vertical vibration of car body excited by wheel eccentricity. The results show that there are three factors which may cause an abnormal vibration considering the track and the vehicle system. The influence of wheel eccentricity on the car body vibration was firstly analyzed. Simulated acceleration of car body has a great accordance with test. The wheel eccentricity could excite the resonance of car body at the speed of 21 km/h, and the vertical acceleration would increase considerably. Decreasing the secondary stiffness can effectively reduce the vertical vibration caused by wheel eccentricity, especially at the resonant speed. In the secondary test, the peak of car body acceleration at speed of 20 km/h is not appearing when only renewing the wheels, and the acceleration is decreasing obviously at the domain frequency. It is further determined that the abnormal vibration is mainly caused by the wheel eccentricity.

  6. Creatine supplementation does not decrease oxidative stress and inflammation in skeletal muscle after eccentric exercise.

    Science.gov (United States)

    Silva, Luciano A; Tromm, Camila B; Da Rosa, Guilherme; Bom, Karoliny; Luciano, Thais F; Tuon, Talita; De Souza, Cláudio T; Pinho, Ricardo A

    2013-01-01

    Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48 h). Cr supplementation was administered as a solution of 300 mg · kg body weight(-1) · day(-1) in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h(-1) until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1β), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1β, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction.

  7. Ultrasound-Guided Percutaneous Electrolysis and Eccentric Exercises for Subacromial Pain Syndrome: A Randomized Clinical Trial

    Science.gov (United States)

    Arias-Buría, José L.; Truyols-Domínguez, Sebastián; Valero-Alcaide, Raquel; Salom-Moreno, Jaime; Atín-Arratibel, María A.; Fernández-de-las-Peñas, César

    2015-01-01

    Objective. To compare effects of ultrasound- (US-) guided percutaneous electrolysis combined with an eccentric exercise program of the rotator cuff muscles in subacromial pain syndrome. Methods. Thirty-six patients were randomized and assigned into US-guided percutaneous electrolysis (n = 17) group or exercise (n = 19) group. Patients were asked to perform an eccentric exercise program of the rotator cuff muscles twice every day for 4 weeks. Participants assigned to US-guided percutaneous electrolysis group also received the application of galvanic current through acupuncture needle on each session once a week (total 4 sessions). Shoulder pain (NPRS) and disability (DASH) were assessed at baseline, after 2 sessions, and 1 week after the last session. Results. The ANOVA revealed significant Group∗Time interactions for shoulder pain and disability (all, P electrolysis combined with the eccentric exercises experienced greater improvement than those receiving eccentric exercise alone. Conclusions. US-guided percutaneous electrolysis combined with eccentric exercises resulted in small better outcomes at short term compared to when only eccentric exercises were applied in subacromial pain syndrome. The effect was statistically and clinically significant for shoulder pain but below minimal clinical difference for function. Future studies should investigate the long-term effects and potential placebo effect of this intervention. PMID:26649058

  8. Ultrasound-Guided Percutaneous Electrolysis and Eccentric Exercises for Subacromial Pain Syndrome: A Randomized Clinical Trial.

    Science.gov (United States)

    Arias-Buría, José L; Truyols-Domínguez, Sebastián; Valero-Alcaide, Raquel; Salom-Moreno, Jaime; Atín-Arratibel, María A; Fernández-de-Las-Peñas, César

    2015-01-01

    Objective. To compare effects of ultrasound- (US-) guided percutaneous electrolysis combined with an eccentric exercise program of the rotator cuff muscles in subacromial pain syndrome. Methods. Thirty-six patients were randomized and assigned into US-guided percutaneous electrolysis (n = 17) group or exercise (n = 19) group. Patients were asked to perform an eccentric exercise program of the rotator cuff muscles twice every day for 4 weeks. Participants assigned to US-guided percutaneous electrolysis group also received the application of galvanic current through acupuncture needle on each session once a week (total 4 sessions). Shoulder pain (NPRS) and disability (DASH) were assessed at baseline, after 2 sessions, and 1 week after the last session. Results. The ANOVA revealed significant Group∗Time interactions for shoulder pain and disability (all, P percutaneous electrolysis combined with the eccentric exercises experienced greater improvement than those receiving eccentric exercise alone. Conclusions. US-guided percutaneous electrolysis combined with eccentric exercises resulted in small better outcomes at short term compared to when only eccentric exercises were applied in subacromial pain syndrome. The effect was statistically and clinically significant for shoulder pain but below minimal clinical difference for function. Future studies should investigate the long-term effects and potential placebo effect of this intervention.

  9. An analytical model of heat generation for eccentric cylindrical pin in friction stir welding

    Directory of Open Access Journals (Sweden)

    Ahmed Ramadan Shaaban Essa

    2016-07-01

    Full Text Available An analytical model for heat generation for eccentric cylindrical pin in friction stir welding was developed that utilizes a new factor based on the tool pin eccentricity. The proposed analytical expression is a modification of previous analytical models from the literature, which is verified and well matches with the model developed by previous researchers. Results of plunge force and peak temperature were used to validate the current proposed model. The cylindrical tool pin with eccentricities of 0, 0.2, and 0.8 mm were used to weld two types of aluminum alloys; a low deformation resistant AA1050-H12, and a relatively high deformation resistant AA5754-H24 alloy. The FSW was performed at constant tool rotation speed of 600 rpm and different welding speeds of 100, 300, and 500 mm/min. Experimental results implied that less temperature is generated using eccentric cylindrical pin than cylindrical pin without eccentricity under the given set of FSW process conditions. Furthermore, numerical simulation results show that increasing the pin eccentricity leads to decrease in peak temperature.

  10. Possible vascular injury due to screw eccentricity in minimally invasive total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Nishant Kumar Singh

    2017-01-01

    Full Text Available Background: Vascular injury during minimally invasive total hip arthroplasty (THA is uncommon, yet a well-recognized and serious issue. It emerges because of non-visibility of vascular structures proximal to the pelvic bone during reaming, drilling holes, and fixing of screws. Numerous studies have found that screw fixation during cementless THA is beneficial for the initial stability of cup; yet, no anatomical guidelines support angular eccentric screw fixation. Materials and Methods: In this study, we obtained the pelvic arterial-phase computed tomographic data of thirty eight humans and reconstructed the three-dimensional models of osseous and vessel structures. We performed the surgical simulation to fix these structures with cementless cups and screws with angular eccentricities. Results: The effect of screw eccentricities (angular eccentricities of ±17° and ±34° on the vascular injury was determined. Measurement between screw and adjoining vessels was performed and analyzed statistically to ascertain a comparative risk study for blood vessels that are not visible during surgery. Conclusion: Authors similarly discussed the significant absence of appreciation of quadrant systems proposed by Wasielewski et al. on eccentric screws. Adjustment of quadrant systems provided by Wasielewski et al. is required for acetabular implants with eccentric holes for fixation of acetabular screws.

  11. EFFECT OF HEAT PRECONDITIONING BY MICROWAVE HYPERTHERMIA ON HUMAN SKELETAL MUSCLE AFTER ECCENTRIC EXERCISE

    Directory of Open Access Journals (Sweden)

    Norio Saga

    2008-03-01

    Full Text Available The purpose of this study was to clarify whether heat preconditioning results in less eccentric exercise-induced muscle damage and muscle soreness, and whether the repeated bout effect is enhanced by heat preconditioning prior to eccentric exercise. Nine untrained male volunteers aged 23 ± 3 years participated in this study. Heat preconditioning included treatment with a microwave hyperthermia unit (150 W, 20 min that was randomly applied to one of the subject's arms (MW; the other arm was used as a control (CON. One day after heat preconditioning, the subjects performed 24 maximal isokinetic eccentric contractions of the elbow flexors at 30°·s-1 (ECC1. One week after ECC1, the subjects repeated the procedure (ECC2. After each bout of exercise, maximal voluntary contraction (MVC, range of motion (ROM of the elbow joint, upper arm circumference, blood creatine kinase (CK activity and muscle soreness were measured. The subjects experienced both conditions at an interval of 3 weeks. MVC and ROM in the MW were significantly higher than those in the CON (p < 0.05 for ECC1; however, the heat preconditioning had no significant effect on upper arm circumference, blood CK activity, or muscle soreness following ECC1 and ECC2. Heat preconditioning may protect human skeletal muscle from eccentric exercise-induced muscle damage after a single bout of eccentric exercise but does not appear to promote the repeated bout effect after a second bout of eccentric exercise

  12. Ultrasound-Guided Percutaneous Electrolysis and Eccentric Exercises for Subacromial Pain Syndrome: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    José L. Arias-Buría

    2015-01-01

    Full Text Available Objective. To compare effects of ultrasound- (US- guided percutaneous electrolysis combined with an eccentric exercise program of the rotator cuff muscles in subacromial pain syndrome. Methods. Thirty-six patients were randomized and assigned into US-guided percutaneous electrolysis (n=17 group or exercise (n=19 group. Patients were asked to perform an eccentric exercise program of the rotator cuff muscles twice every day for 4 weeks. Participants assigned to US-guided percutaneous electrolysis group also received the application of galvanic current through acupuncture needle on each session once a week (total 4 sessions. Shoulder pain (NPRS and disability (DASH were assessed at baseline, after 2 sessions, and 1 week after the last session. Results. The ANOVA revealed significant Group∗Time interactions for shoulder pain and disability (all, P<0.01: individuals receiving US-guided percutaneous electrolysis combined with the eccentric exercises experienced greater improvement than those receiving eccentric exercise alone. Conclusions. US-guided percutaneous electrolysis combined with eccentric exercises resulted in small better outcomes at short term compared to when only eccentric exercises were applied in subacromial pain syndrome. The effect was statistically and clinically significant for shoulder pain but below minimal clinical difference for function. Future studies should investigate the long-term effects and potential placebo effect of this intervention.

  13. Re-evaluation of sarcolemma injury and muscle swelling in human skeletal muscles after eccentric exercise.

    Science.gov (United States)

    Yu, Ji-Guo; Liu, Jing-Xia; Carlsson, Lena; Thornell, Lars-Eric; Stål, Per S

    2013-01-01

    The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS) induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2-3 days and 7-8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7-8 days than at 2-3 days post exercise (pmuscle is not directly associated with the symptom of DOMS.

  14. Probabilistic infrasound propagation using realistic atmospheric perturbations

    NARCIS (Netherlands)

    Smets, P.S.M.; Evers, L.G.; Näsholm, S.P.; Gibbons, S.J.

    2015-01-01

    This study demonstrates probabilistic infrasound propagation modeling using realistic perturbations. The ensembles of perturbed analyses, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), include error variances of both model and assimilated observations. Ensemble spread

  15. Perturbation theory and renormalisation group equations

    CERN Document Server

    Litim, Daniel F; Litim, Daniel F.; Pawlowski, Jan M.

    2002-01-01

    We discuss the perturbative expansion of several one-loop improved renormalisation group equations. It is shown that in general the integrated renormalisation group flows fail to reproduce perturbation theory beyond one loop.

  16. The Effects of Eccentric Contraction Duration on Muscle Strength, Power Production, Vertical Jump, and Soreness.

    Science.gov (United States)

    Mike, Jonathan N; Cole, Nathan; Herrera, Chris; VanDusseldorp, Trisha; Kravitz, Len; Kerksick, Chad M

    2017-03-01

    Mike, JN, Cole, N, Herrera, C, VanDusseldorp, T, Kravitz, L, and Kerksick, CM. The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. J Strength Cond Res 31(3): 773-786, 2017-Previous research has investigated the effects of either eccentric-only training or comparing eccentric and concentric exercise on changes related to strength and power expression, but no research to date has investigated the impact of altering the duration of either the concentric or the eccentric component on these parameters. Therefore, the purpose of this study was to assess the duration of eccentric (i.e., 2-second, 4-second vs. 6-second) muscle contractions and their effect on muscle strength, power production, vertical jump, and soreness using a plate-loaded barbell Smith squat exercise. Thirty college-aged men (23 ± 3.5 years, 178 ± 6.8 cm, 82 ± 12 kg, and 11.6 ± 5.1% fat) with 3.0 ± 1.0 years of resistance training experience and training frequency of 4.3 ± 0.9 days per week were randomized and assigned to 1 of 3 eccentric training groups that incorporated different patterns of contraction. For every repetition, all 3 groups used 2-second concentric contractions and paused for 1 second between the concentric and eccentric phases. The control group (2S) used 2-second eccentric contractions, whereas the 4S group performed 4-second eccentric contractions and the 6S group performed 6-second eccentric contractions. All repetitions were completed using the barbell Smith squat exercise. All participants completed a 4-week training protocol that required them to complete 2 workouts per week using their prescribed contraction routine for 4 sets of 6 repetitions at an intensity of 80-85% one repetition maximum (1RM). For all performance data, significant group × time (G × T) interaction effects were found for average power production across all 3 sets of a squat jump protocol (p = 0.04) while vertical jump did not reach

  17. Mean Motion Resonances at High Eccentricities: The 2:1 and the 3:2 Interior Resonances

    Science.gov (United States)

    Wang, Xianyu; Malhotra, Renu

    2017-07-01

    Mean motion resonances (MMRs) play an important role in the formation and evolution of planetary systems and have significantly influenced the orbital properties and distribution of planets and minor planets in the solar system and in exoplanetary systems. Most previous theoretical analyses have focused on the low- to moderate-eccentricity regime, but with new discoveries of high-eccentricity resonant minor planets and even exoplanets, there is increasing motivation to examine MMRs in the high-eccentricity regime. Here we report on a study of the high-eccentricity regime of MMRs in the circular planar restricted three-body problem. Numerical analyses of the 2:1 and the 3:2 interior resonances are carried out for a wide range of planet-to-star mass ratio μ, and for a wide range of eccentricity of the test particle. The surface-of-section technique is used to study the phase space structure near resonances. We find that new stable libration zones appear at higher eccentricity at libration centers that are shifted from those at low eccentricities. We provide physically intuitive explanations for these transitions in phase space, and we present novel results on the mass and eccentricity dependence of the resonance widths. Our results show that MMRs have sizable libration zones at high eccentricities, comparable to those at lower eccentricities.

  18. Possible Outcomes of Coplanar High-eccentricity Migration: Hot Jupiters, Close-in Super-Earths, and Counter-orbiting Planets

    Science.gov (United States)

    Xue, Yuxin; Masuda, Kento; Suto, Yasushi

    2017-02-01

    We investigate the formation of close-in planets in near-coplanar eccentric hierarchical triple systems via the secular interaction between an inner planet and an outer perturber (Coplanar High-eccentricity Migration; CHEM). We generalize the previous work on the analytical condition for successful CHEM for point masses interacting only through gravity by taking into account the finite mass effect of the inner planet. We find that efficient CHEM requires that the systems should have m1 ≪ m0 and m1 ≪ m2. In addition to the gravity for point masses, we examine the importance of the short-range forces, and provide an analytical estimate of the migration timescale. We perform a series of numerical simulations in CHEM for systems consisting of a Sun-like central star, giant gas inner planet, and planetary outer perturber, including the short-range forces and stellar and planetary dissipative tides. We find that most of such systems end up with a tidal disruption; a small fraction of the systems produce prograde hot Jupiters (HJs), but no retrograde HJ. In addition, we extend CHEM to super-Earth mass range, and show that the formation of close-in super-Earths in prograde orbits is also possible. Finally, we carry out CHEM simulation for the observed hierarchical triple and counter-orbiting HJ systems. We find that CHEM can explain a part of the former systems, but it is generally very difficult to reproduce counter-orbiting HJ systems.

  19. FRW Cosmological Perturbations in Massive Bigravity

    CERN Document Server

    Comelli, D; Pilo, L

    2014-01-01

    Cosmological perturbations of FRW solutions in ghost free massive bigravity, including also a second matter sector, are studied in detail. At early time, we find that sub horizon exponential instabilities are unavoidable and they lead to a premature departure from the perturbative regime of cosmological perturbations.

  20. Matrix perturbations: bounding and computing eigenvalues

    NARCIS (Netherlands)

    Reis da Silva, R.J.

    2011-01-01

    Despite the somewhat negative connotation of the word, not every perturbation is a bad perturbation. In fact, while disturbing the matrix entries, many perturbations still preserve useful properties such as the orthonormality of the basis of eigenvectors or the Hermicity of the original matrix. In

  1. Aging interferes central control mechanism for eccentric muscle contraction.

    Science.gov (United States)

    Yao, Wan X; Li, Jinqi; Jiang, Zhiguo; Gao, Jia-Hong; Franklin, Crystal G; Huang, Yufei; Lancaster, Jack L; Yue, Guang H

    2014-01-01

    Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional magnetic resonance imaging (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.

  2. Can the Presence of a Surrounding Endometrium Differentiate Eccentrically Located Intrauterine Pregnancy from Interstitial Ectopic Pregnancy?

    Science.gov (United States)

    Grant, Allison; Murji, Ally; Atri, Mostafa

    2017-08-01

    Differentiation of an eccentric intrauterine pregnancy (IUP) from an interstitial ectopic pregnancy (EP) is challenging. No sign for differentiation is reported. The purpose of this study was to determine whether the presence of surrounding endometrium (SE) can distinguish eccentric IUP from interstitial EP. This study was approved by the institutional ethics board; consent acquisition was waived. Cases were identified using ultrasound (US) reports that included the words "interstitial," "cornual," and "angular." Blinded to official reports, one reviewer reviewed US examinations retrospectively for the presence of SE, defined as the extension of endometrial lining around the gestational sac (GS) as an indication of an eccentric IUP. US examinations without SE on the retrospective review were diagnosed as interstitial EP. Forty-four cases were identified from 2007 to 2015. On retrospective review, 20 cases were labeled as eccentric IUP and 24 as interstitial EP. Ten of the 20 cases retrospectively labeled as eccentric IUP had been reported and managed as eccentric IUP prospectively: four followed to a viable second trimester, and six had spontaneous abortion/termination. The remaining 10 cases retrospectively labeled eccentric IUPs because of the presence of SE had been reported and managed as interstitial EP on the official prospective report. There was follow-up suggestion of eccentric IUP in six of the latter discordant pregnancies with non-concordant retrospective and prospective diagnosis: three had hysteroscopy/curettage demonstrating retained products, two had US follow-up showing the GS moving farther down in the uterine cavity, and in one patient, the GS was shown to pass per vagina. Twenty-four of the 44 cases were called interstitial EP both on the retrospective and prospective reviews and were managed as interstitial EP. None of these patients (without SE) had follow-up suggestive of eccentric IUP. Our results suggest that the presence of surrounding

  3. Tidal disruption events from eccentric nuclear disks in post-merger galaxies

    Science.gov (United States)

    Madigan, Ann-Marie

    Surprisingly, in more than twenty percent of nearby elliptical galaxies, the distribution of stars orbiting the central supermassive black hole is strongly asymmetric. In these galaxies, the stars are on apsidally-aligned orbits in an eccentric nuclear disk. Long thought to be exotic, this configuration is quite common in our local universe. Despite the prevalence of eccentric disks however, their dynamics have been largely overlooked. Naively, one might expect that packing orbits so closely together would make them violently unstable to gravitational scattering, or that differential precession would wipe out their large-scale apsidal-alignment. We have recently identified a new dynamical mechanism which stabilizes eccentric nuclear disks (Madigan et al., 2016), thus explaining their observed ubiquity. The stabilizing mechanism produces oscillations of orbital eccentricities of stars in the disk, pushing many stars extremely close to the black hole. If these disks form in gas-rich mergers, as is found in cosmological simulations, there will be an enhanced rate of stellar tidal disruption events (TDEs) following the merger. In a preliminary calculation, we show the TDE rate is initially so high that the nucleus would appear as an AGN, or as a changing-look-quasar. We therefore suggest that accretion of dense stellar material may contribute significantly to the growth of supermassive black holes; if so, this could explain the presence of supermassive black holes in the extremely early universe, z>7, as well as the peaking of quasar activity around z 2, when the galaxy merger rate peaks. Our model can also explain the recently observed preference of TDEs in post-merger, post-starburst (K+A) galaxies. Here we propose to quantify these calculations. We will also undertake a statistical analysis of the literature to determine the true occurrence rate of eccentric nuclear disks. Long after the merger and the K+A phase, eccentric disks no longer directly produce TDEs

  4. The Homotopy Perturbation Method for Accurate Orbits of the Planets in the Solar System: The Elliptical Kepler Equation

    Science.gov (United States)

    Alshaery, Aisha

    2017-09-01

    Accurate trajectories for the orbits of the planets in our solar system depends on obtaining an accurate solution for the elliptical Kepler equation. This equation is solved in this article using the homotopy perturbation method. Several properties of the periodicity of the obtained approximate solutions are introduced through some lemmas. Numerically, our calculations demonstrated the applicability of the obtained approximate solutions for all the planets in the solar system and also in the whole domain of eccentricity and mean anomaly. In the whole domain of the mean anomaly, 0≤M≤2π, and by using the different approximate solutions, the residuals were less than 4×10-17 for e∈[0, 0.06], 4×10-9 for e∈[0.06, 0.25], 3×10-8 for e∈[0.25, 0.40], 3×10-7 for e∈[0.40, 0.50], and 10-6 for e∈[0.50, 1.0]. Also, the approximate solutions were compared with the Bessel-Fourier series solution in the literature. In addition, the approximate homotopy solutions for the eccentric anomaly are used to show the convergence and periodicity of the approximate radial distances of Mercury and Pluto for three and five periods, respectively, as confirmation for some given lemmas. It has also been shown that the present analysis can be successfully applied to the orbit of Halley's comet with a significant eccentricity.

  5. Perturbed solitons in birefringent fibres

    CERN Document Server

    Horikis, T P

    2003-01-01

    A perturbation theory based on inverse scattering theory is developed for the coupled nonlinear Schroedinger equations. The theory finds useful application to the study of pulse propagation down a birefringent optical fibre and is used to examine features of the radiation field shed by a soliton pulse propagating down the fibre. The radiation field is linked to the scattering data through a transform pair which in the linear limit reduces to the forward and inverse Fourier transform pair. A complementary approach, which is in total agreement to these results, is also discussed.

  6. Resonant-state perturbation formalisms

    Energy Technology Data Exchange (ETDEWEB)

    Romo, W.J. (Carleton Univ., Ottawa, Ontario (Canada). Dept. of Physics)

    1983-05-02

    Three different formalisms for determining bound-state, virtual-state, and resonant-state energies of a perturbed system are developed. Two of the formalisms are based on expansions of the unperturbed Green function in terms of bound-state, resonant-state and deformed-continuum-state contributions of the form developed by T. Berggren. The third formalism is based on a Mittag-Leffler expansion of the unperturbed Green function. The three formalisms are compared and the relative merits of calculation schemes based on them are examined.

  7. Effect of transcutaneous electromyostimulation on pressure pain threshold and tolerance in athletes under eccentric exercise

    Directory of Open Access Journals (Sweden)

    Selman Burak UĞURLU

    2014-08-01

    Full Text Available Exercise - induced hypoalgesia typically reported during and / or follow ing exercise. In this study, we investigated the role of transcutaneous electromyostimulation (EMS on pressure pain threshold and tolerance in athletes under eccentric exercise. Eleven male athletes aged 23,125 ± 0,99 years with 10,25 ± 2,66 years of athl etic training were recruited for this study . Following baseline measurements of pressure pain threshold and tolerance from m. biceps brachii and m. triceps brachii muscle and myofascial regions of the dominant upper extremity by using a digital algometer, subjects were underwent an acute bout of eccentric exercise. Participants were completed 4 sets of eccentric exercise each comprising 20 repetitions of lifting 80% of their 1 RM by using a dumbbell. Pressure pain threshold and tolerance tests were repeated 10, 20 and 30 minutes, and 24 and 48 hours following exercise. One week after acute exercise protocol, EMS protocol was applied to the participants immediately following eccentric exercise, and all measurements were repeated at the same timeline as eccent ric exercise. Standard EMS protocol at active recovery mode for 10 minutes was applied to the m. biceps brachii muscle by using surface electrodes. Results are presented as mean + standarts deviation. Data of the same timeline were analyzed by using repeat ed measures of ANOVA followed by Tukey’s post hoc test . A level of p<0.05 was accepted statistical significant. Eccentric exercise resulted to increase the pain tolerence in athletes, and EMS was found to decrease the pain tolerence 10 and 20 minutes at th e muscle region, and 10 and 30 minutes, and 24 hours at the myofascial region of m. biceps brachii, 10 min and 24 hr from muscle region, 10 and 30 min and 24 hr from myofascial region of M. triceps brachii following acute bout of eccentric exercise. We con cluded that EMS at active recovery phase mitigates the the hypoalgesic response following single bout of

  8. Forming Different Planetary Architectures. I. The Formation Efficiency of Hot Jupiters from High-eccentricity Mechanisms

    Science.gov (United States)

    Wang, Ying; Zhou, Ji-lin; hui-gen, Liu; Meng, Zeyang

    2017-10-01

    Exoplanets discovered over the past decades have provided a new sample of giant exoplanets: hot Jupiters. For lack of enough materials in the current locations of hot Jupiters, they are perceived to form outside the snowline. Then, they migrate to the locations observed through interactions with gas disks or high-eccentricity mechanisms. We examined the efficiencies of different high-eccentricity mechanisms for forming hot Jupiters in near-coplanar multi-planet systems. These mechanisms include planet-planet scattering, the Kozai-Lidov mechanism, coplanar high-eccentricity migration, and secular chaos, as well as other two new mechanisms that we present in this work, which can produce hot Jupiters with high inclinations even in retrograde. We find that the Kozai-Lidov mechanism plays the most important role in producing hot Jupiters among these mechanisms. Secular chaos is not the usual channel for the formation of hot Jupiters due to the lack of an angular momentum deficit within {10}7{T}{in} (periods of the inner orbit). According to comparisons between the observations and simulations, we speculate that there are at least two populations of hot Jupiters. One population migrates into the boundary of tidal effects due to interactions with the gas disk, such as ups And b, WASP-47 b, and HIP 14810 b. These systems usually have at least two planets with lower eccentricities, and remain dynamically stable in compact orbital configurations. Another population forms through high-eccentricity mechanisms after the excitation of eccentricity due to dynamical instability. These kinds of hot Jupiters usually have Jupiter-like companions in distant orbits with moderate or high eccentricities.

  9. Intra-tester Reliability and Construct Validity of a Hip Abductor Eccentric Strength Test.

    Science.gov (United States)

    Brindle, Richard A; Ebaugh, D David; Milner, Clare E

    2017-11-15

    Side-lying hip abductor strength tests are commonly used to evaluate muscle strength. In a 'break' test the tester applies sufficient force to lower the limb to the table while the patient resists. The peak force is postulated to occur while the leg is lowering, thus representing the participant's eccentric muscle strength. However, it is unclear whether peak force occurs before or after the leg begins to lower. To determine intra-rater reliability and construct validity of a hip abductor eccentric strength test. Intra-rater reliability and construct validity study. Twenty healthy adults (26 ±6 years; 1.66 ±0.06 m; 62.2 ±8.0 kg) made two visits to the laboratory at least one week apart. During the hip abductor eccentric strength test, a hand-held dynamometer recorded peak force and time to peak force and limb position was recorded via a motion capture system. Intra-rater reliability was determined using intra-class correlation (ICC), standard error of measurement (SEM), and minimal detectable difference (MDD). Construct validity was assessed by determining if peak force occurred after the start of the lowering phase using a one-sample t-test. The hip abductor eccentric strength test had substantial intra-rater reliability (ICC(3,3) = 0.88; 95% confidence interval: 0.65-0.95), SEM of 0.9%BWh, and a MDD of 2.5%BWh. Construct validity was established as peak force occurred 2.1s (±0.6s; range 0.7s to 3.7s) after the start of the lowering phase of the test (p ≤ 0.001). The hip abductor eccentric strength test is a valid and reliable measure of eccentric muscle strength. This test may be used clinically to assess changes in eccentric muscle strength over time.

  10. Unilateral eccentric contraction of the plantarflexors leads to bilateral alterations in leg dexterity

    Directory of Open Access Journals (Sweden)

    Akira Nagamori

    2016-11-01

    Full Text Available Eccentric contractions can affect musculotendon mechanical properties and disrupt muscle proprioception, but their behavioral consequences are poorly understood. We tested whether repeated eccentric contractions of plantarflexor muscles of one leg affected the dexterity of either leg. Twenty healthy male subjects (27.3+/-4.0 yrs compressed a compliant and slender spring prone to buckling with each isolated leg. The maximal instability they could control (i.e., the maximal average sustained compression force, or lower extremity dexterity force, LEDForce quantified the dexterity of each leg. We found that eccentric contractions did not affect LEDForce, but reduced force variability (LEDSD. Surprisingly, LEDForce increased in the non-exposed, contralateral leg. These effects were specific to exposure to eccentric contractions because an effort-matched exposure to walking did not affect leg dexterity. In the exposed leg, eccentric contractions (i reduced voluntary error corrections during spring compressions (i.e., reduced 0.5-4 Hz power of LEDForce; (ii did not change spinal excitability (i.e., unaffected H-reflexes; and (iii changed the structure of the neural drive to the alpha-motoneuron pool (i.e., reduced EMG power within the 4-8 Hz physiological tremor band. These results suggest that repeated eccentric contractions alter the feedback control for dexterity in the exposed leg by reducing muscle spindle sensitivity. Moreover, the unexpected improvement in LEDForce in the non-exposed contralateral leg was likely a consequence of crossed-effects on its spinal and supraspinal feedback control. We discuss the implications of these bilateral effects of unilateral eccentric contractions, their effect on spinal and supraspinal control of dynamic foot-ground interactions, and their potential to facilitate rehabilitation from musculoskeletal and neuromotor impairments.

  11. The effects of K+ channel blockade on eccentric and isotonic twitch and fatiguing contractions in situ

    Directory of Open Access Journals (Sweden)

    Michelle eMoyer

    2012-09-01

    Full Text Available K+ channel blockers like 3,4-diaminopyridine (DAP can double isometric muscle force. Functional movements require more complex concentric and eccentric contractions, however the effects of K+ channel blockade on these types of contractions in situ are unknown. Extensor digitorum longus (EDL muscles were stimulated in situ with and without DAP in anesthetized rats and fatigability was addressed using a series of either concentric or eccentric contractions. During isotonic protocols (5-100% load, DAP significantly shifted shortening- and maximum shortening velocity-load curves upward and to the right and increased power and work. Maximum shortening, maximum shortening velocity and power doubled while work increased by approximately 250% during isotonic contraction at 50% load. During isotonic fatigue, DAP significantly augmented maximum shortening, work, shortening velocity and power. During constant velocity eccentric protocols (2-12 mm/s, DAP increased muscle force during eccentric contractions at 6, 8, 10 and 12 mm/s. During eccentric contraction at a constant velocity of 6mm/s while varying the stimulation frequency, DAP significantly increased muscle force during 20, 40 and 70 Hz . The effects of DAP on muscle contractile performance during eccentric fatigue varied with level of fatigue. DAP-induced contractile increases during isotonic contractions were similar to those produced during previously studied isometric contractions, while the DAP effect during eccentric contractions was more modest. These findings are especially important in attempting to optimize functional electrical stimulation parameters for spinal cord injury patients while also preventing rapid fatigue of those muscles.

  12. Chronic ankle instability alters eccentric eversion/inversion and dorsiflexion/plantarflexion ratio.

    Science.gov (United States)

    Abdel-aziem, Amr Almaz; Draz, Amira Hussin

    2014-01-01

    To determine if the eccentric evertor/invertor and dorsiflexor/plantar-flexor ratio are altered in subjects with chronic ankle instability. Twenty chronic ankle instability (CAI) subjects as an experimental group, and twenty healthy subjects as a control group, were matched in age, gender, and activity level. CAI subjects have a history of at least one ankle sprain and repeated episodes of giving way were included in CAI group. Subjects with no prior history of ankle injury were included in the control group. Ankle evertor/invertor and dorsiflexor/plantar-flexor muscles eccentric torque ratios were measured using the eccentric muscle contraction at angular velocities 60 and 120°/s. Analysis of variance revealed that the eccentric contraction eversion/inversion ratio of CAI group was significantly lower than normal group ratio at angular velocities 60 and 120°/s (p=0.041 and 0.012) respectively. The eccentric contraction dorsiflexion/plantarflexion ratio of CAI group was significantly higher than normal group ratio at both angular velocities (p=0.036 and 0.013) respectively. Moreover, at angular velocities of 60°/s and 120°/s a deficit in inversion and eversion eccentric torques were identified in CAI group (p=0.000), plantarflexion torque deficit of CAI group (p=0.034 and 0.028), respectively, and no deficit was identified for dorsiflexion torque of CAI group (p=0.595 and 0.696) respectively. Chronic ankle instability increases the dorsiflexion/plantarflexion muscles torque ratio and decreases the eversion/inversion ratio at angular velocities 60 and 120°/s. Therefore, the restoration of a normal eccentric inversion, eversion, and plantarflexion strength may prevent recurrent lateral ankle ligament sprain.

  13. Circumplanetary Debris Disks and Consequences of an Eccentric Fomalhaut b

    Science.gov (United States)

    Tamayo, Daniel; Burns, J. A.

    2013-10-01

    Each of the Solar System’s giant planets hosts many small and distant irregular satellites. These moons’ radially overlapping orbits and their unusually shallow size distributions imply a violent collisional history (Bottke et al. 2010). Thus, at early epochs, the giant planets likely displayed prominent circumplanetary debris clouds. For my PhD I numerically studied how such debris in the Saturnian system would evolve inward through radiation forces to coat the striking two-faced moon Iapetus (Tamayo et al. 2011). I also investigated the analogous process at Uranus, where the planet’s extreme obliquity renders infalling dust orbits chaotic. We find that this could explain the color dichotomies observed on the largest four Uranian satellites (Tamayo et al. 2013a, 2013b). Even today, Saturn has such a vast dust disk, sourced by the irregular satellite Phoebe (Verbiscer et al. 2009). This ‘Phoebe Ring’, can be used to observationally study the gravitational effects of moons on the dust; I have successfully probed this ring with Cassini, but was unsuccessful with Herschel observations. By these combined observational and dynamical studies, I hope to inform the field of extrasolar debris disks, where one tries to use dust signatures to infer the existence of planets that are too faint to see. I am now focusing on a related problem involving the exoplanet candidate Fomalhaut b (Kalas et al. 2008). While its optical flux is too large to come directly from a planet, perhaps we are observing a disk supplied by irregular moons (Kennedy & Wyatt 2011). Additional observation epochs imply that Fomalhaut-b’s orbit is very eccentric (Kalas et al. 2013). Yet despite crossing the system’s observed circumstellar debris disk in projection, Fomalhaut b does not appear to have significantly disturbed it. We argue from simulations that if Fomalhaut b is a giant planet, it must have scattered into its present orbit in the past ~10 Myr. If so, the young Fomalhaut system 400

  14. HAMSTRING ARCHITECTURAL AND FUNCTIONAL ADAPTATIONS FOLLOWING LONG VS. SHORT MUSCLE LENGTH ECCENTRIC TRAINING

    Directory of Open Access Journals (Sweden)

    Kenny Guex

    2016-08-01

    Full Text Available Most common preventive eccentric-based exercises, such as Nordic hamstring do not include any hip flexion. So, the elongation stress reached is lower than during the late swing phase of sprinting. The aim of this study was to assess the evolution of hamstring architectural (fascicle length and pennation angle and functional (concentric and eccentric optimum angles and concentric and eccentric peak torques parameters following a 3-week eccentric resistance program performed at long (LML versus short muscle length (SML. Both groups performed eight sessions of 3-5x8 slow maximal eccentric knee extensions on an isokinetic dynamometer: the SML group at 0° and the LML group at 80° of hip flexion. Architectural parameters were measured using ultrasound imaging and functional parameters using the isokinetic dynamometer. The fascicle length increased by 4.9% (p<0.01, medium effect size in the SML and by 9.3% (p<0.001, large effect size in the LML group. The pennation angle did not change (p=0.83 in the SML and tended to decrease by 0.7° (p=0.09, small effect size in the LML group. The concentric optimum angle tended to decrease by 8.8° (p=0.09, medium effect size in the SML and by 17.3° (p<0.01, large effect size in the LML group. The eccentric optimum angle did not change (p=0.19, small effect size in the SML and tended to decrease by 10.7° (p=0.06, medium effect size in the LML group. The concentric peak torque did not change in the SML (p=0.37 and the LML (p=0.23 groups, whereas eccentric peak torque increased by 12.9% (p<0.01, small effect size and 17.9% (p<0.001, small effect size in the SML and the LML group, respectively. No group-by-time interaction was found for any parameters. A correlation was found between the training-induced change in fascicle length and the change in concentric optimum angle (r=-0.57, p<0.01. These results suggest that performing eccentric exercises lead to several architectural and functional adaptations. However

  15. Physiological Mechanisms of Eccentric Contraction and Its Applications: A Role for the Giant Titin Protein

    Science.gov (United States)

    Hessel, Anthony L.; Lindstedt, Stan L.; Nishikawa, Kiisa C.

    2017-01-01

    When active muscles are stretched, our understanding of muscle function is stretched as well. Our understanding of the molecular mechanisms of concentric contraction has advanced considerably since the advent of the sliding filament theory, whereas mechanisms for increased force production during eccentric contraction are only now becoming clearer. Eccentric contractions play an important role in everyday human movements, including mobility, stability, and muscle strength. Shortly after the sliding filament theory of muscle contraction was introduced, there was a reluctant recognition that muscle behaved as if it contained an “elastic” filament. Jean Hanson and Hugh Huxley referred to this structure as the “S-filament,” though their concept gained little traction. This additional filament, the giant titin protein, was identified several decades later, and its roles in muscle contraction are still being discovered. Recent research has demonstrated that, like activation of thin filaments by calcium, titin is also activated in muscle sarcomeres by mechanisms only now being elucidated. The mdm mutation in mice appears to prevent activation of titin, and is a promising model system for investigating mechanisms of titin activation. Titin stiffness appears to increase with muscle force production, providing a mechanism that explains two fundamental properties of eccentric contractions: their high force and low energetic cost. The high force and low energy cost of eccentric contractions makes them particularly well suited for athletic training and rehabilitation. Eccentric exercise is commonly prescribed for treatment of a variety of conditions including sarcopenia, osteoporosis, and tendinosis. Use of eccentric exercise in rehabilitation and athletic training has exploded to include treatment for the elderly, as well as muscle and bone density maintenance for astronauts during long-term space travel. For exercise intolerance and many types of sports injuries

  16. Clinical outcomes of the addition of eccentrics for rehabilitation of previously failed treatments of golfers elbow.

    Science.gov (United States)

    Tyler, Timothy F; Nicholas, Stephen J; Schmitt, Brandon M; Mullaney, Michael; Hogan, Daniel E

    2014-05-01

    Eccentric training of the wrist extensors has been shown to be effective in treating chronic lateral epicondylosis. However, its efficacy in the treatment of medial epicondylosis has yet to be demonstrated. The objective of this study was to assess the effectiveness of a novel eccentric wrist flexor exercise added to standard treatment for chronic medial epicondylosis in patients who did not respond to previous therapeutic interventions for this disorder. 20. Patients (13 men, 7 women; age 49±12 yr) with chronic medial epicondylosis who had failed previous treatment for this disorder (physical therapy 7, cortisone injection 7, PRP 1, NSAIDS 15) were prescribed isolated eccentrics in addition to wrist stretching, ultrasound, cross-friction massage, heat and ice. The specific isolated eccentric wrist flexor strengthening exercise performed by the patients involved twisting a rubber bar (Flexbar, Hygenic Corportation, Akron OH) with concentric wrist flexion of the noninvolved arm and releasing the twist by eccentrically contracting the wrist flexors of the involved arm (3 × 15 twice daily). A DASH questionnaire was recorded at baseline and again after the treatment period. Treating clinicians were blinded to baseline DASH scores. Treatment effect was assessed using paired t-test. Based on previous work it was estimated that with a sample of 20 patients there would be 80% power to detect a 13 point improvement in DASH scores (ptennis (2), basketball (1), weight lifting (1), and general activities of daily living (2). There was a significant improvement in outcomes following the addition of isolated eccentrics (Pre DASH 34.7±16.2 vs. Post DASH 7.9±11.1, p<.001). For the 18 patients involved in sports, the sports module of the DASH score improved from 73.9±28.9 to 13.2±25.0, p<.001). Physical therapy visits ranged from 1-22 with an average of 12±6 and, average treatment duration of 6.1±2.5 wks (range 1-10). Home exercise program compliance was recorded for each

  17. The effect of temperature on eccentric contraction-induced isometric force loss in isolated perfused rat medial gastrocnemius muscle

    Directory of Open Access Journals (Sweden)

    Vasaghi Gharamaleki B

    2008-09-01

    Full Text Available "nBackground: The typical features of eccentric exercise-induced muscle damage are delayed-onset muscle soreness (DOMS and prolonged loss of muscle strength. It has been shown that passive warmth is effective in reducing muscle injury. Due to the interaction of different systems in vivo, we used isolated perfused medial gastrocnemius skeletal muscle to study the direct effect of temperature on the eccentric contraction-induced force loss. "nMethods: After femoral artery cannulation of a rat, the left medial gastrocnemius muscle was separated and then the entire lower limb was transferred into a prewarmed (35oC chamber. With the chamber temperature at 31, 35 and 39oC before and during eccentric contraction. Isometric force loss was measured after 15 eccentric contractions (N=7-9. "nResults: Maximum contraction force reduction has been used as an index for eccentric contraction-induced force loss. In this study eccentric contraction caused a significant reduction in maximum isometric tension (p<0.01, but no significant difference was seen in isometric force loss at 31oC and 39oC compared with that at 35oC. "nConclusions: Our results suggest that temperature changes before or during eccentric contractions have no effect on eccentric contraction-induced force loss. "nKeywords: Isolated perfused muscle, skeletal muscle, eccentric contractions, isometric force, gastrocnemius muscle, temperature.

  18. Dynamical Properties of Eccentric Nuclear Disks: Stability, Longevity, and Implications for Tidal Disruption Rates in Post-merger Galaxies

    Science.gov (United States)

    Madigan, Ann-Marie; Halle, Andrew; Moody, Mackenzie; McCourt, Michael; Nixon, Chris; Wernke, Heather

    2018-02-01

    In some galaxies, the stars orbiting the supermassive black hole take the form of an eccentric nuclear disk, in which every star is on a coherent, apsidally aligned orbit. The most famous example of an eccentric nuclear disk is the double nucleus of Andromeda, and there is strong evidence for many more in the local universe. Despite their apparent ubiquity, however, a dynamical explanation for their longevity has remained a mystery: differential precession should wipe out large-scale apsidal-alignment on a short timescale. Here we identify a new dynamical mechanism which stabilizes eccentric nuclear disks, and explain for the first time the negative eccentricity gradient seen in the Andromeda nucleus. The stabilizing mechanism drives oscillations of the eccentricity vectors of individual orbits, both in direction (about the mean body of the disk) and in magnitude. Combined with the negative eccentricity gradient, the eccentricity oscillations push some stars near the inner edge of the disk extremely close to the black hole, potentially leading to tidal disruption events (TDEs). Order of magnitude calculations predict extremely high rates in recently formed eccentric nuclear disks (∼0.1–1 {{yr}}-1 {{gal}}-1). Unless the stellar disks are replenished, these rates should decrease with time as the disk depletes in mass. If eccentric nuclear disks form during gas-rich major mergers, this may explain the preferential occurrence of TDEs in recently merged and post-merger (E+A/K+A) galaxies.

  19. Influence on Strength and Flexibility of a Swing Phase-Specific Hamstring Eccentric Program in Sprinters' General Preparation.

    Science.gov (United States)

    Guex, Kenny J; Lugrin, Véronique; Borloz, Stéphane; Millet, Grégoire P

    2016-02-01

    Hamstring injuries are common in sprinters and mainly occur during the terminal swing phase. Eccentric training has been shown to reduce hamstring injury rate by improving several risk factors. The aim of this study was to test the hypothesis that an additional swing phase-specific hamstring eccentric training in well-trained sprinters performed at the commencement of the winter preparation is more efficient to improve strength, ratio, optimum angle, and flexibility than a similar program without hamstring eccentric exercises. Twenty sprinters were randomly allocated to an eccentric (n = 10) or a control group (n = 10). Both groups performed their usual track and field training throughout the study period. Sprinters in the eccentric group performed an additional 6-week hamstring eccentric program, which was specific to the swing phase of the running cycle (eccentric high-load open-chain kinetic movements covering the whole hamstring length-tension relationship preformed at slow to moderate velocity). Isokinetic and flexibility measurements were performed before and after the intervention. The eccentric group increased hamstring peak torques in concentric at 60° · s(-1) by 16% (p training in sprinters seems to be crucial to address different risk factors for hamstring strain injuries, such as eccentric and concentric strength, hamstring-to-quadriceps ratio ratio, and flexibility.

  20. Exciting (and detecting) gravitational waves from the tidally produced f-modes in highly eccentric neutron star binaries

    Science.gov (United States)

    Chirenti, Cecilia; Gold, Roman; Miller, M. Coleman

    2017-08-01

    After the first recent detections of gravitational waves from binary black holes, we expect to observe next gravitational radiation from neutron stars in the near future. Most interestingly, the signal from neutron star binaries could also carry information about the equation of state of cold, catalyzed, dense matter in the interior of neutron stars, which is in a regime not accessible to nuclear and particle physics experiments on Earth. For analyzing this information, more advanced gravitational wave detectors will be needed, such as third-generation detectors like the Einstein Telescope or the Cosmic Explorer. Besides the gravitational wave signal produced by the orbital motion and merger of the binary, a rich spectrum of characteristic fluid oscillations is expected to be produced with low amplitude in the ringdown. The frequencies and physical properties of these modes have been extensively studied in linear perturbation theory (both Newtonian and relativistic) and they have already been found in numerical relativity simulations of isolated neutron stars and of hypermassive remnants of double neutron star mergers. Due to the high frequency of the fundamental (f-)modes, of the order of 1-2 kHz, the resonant excitation of these modes is not expected to be detectable in circular binaries. However, highly eccentric binaries could have the potential for exciting f-modes in their close passages, and recent numerical relativity simulations indicate that the energy deposited in the f-modes could be up to two orders of magnitude greater than predicted in the linear theory. The merger of highly eccentric neutron star binaries will be rare events, but we estimate that up to several tens could be detected per year out to the redshifts ~2-6 accessible with third-generation instruments. Finally, we note that the information from the amplitude, frequency and damping time of the f-modes can be used for simultaneously measuring the masses, moments of inertia and tidal Love

  1. Densities and eccentricities of 139 Kepler planets from transit time variations

    Energy Technology Data Exchange (ETDEWEB)

    Hadden, Sam; Lithwick, Yoram [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)

    2014-05-20

    We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of the order of a few percent. More precisely, the rms eccentricity is 0.018{sub −0.004}{sup +0.005}, and planets smaller than 2.5 R {sub ⊕} are around twice as eccentric as those bigger than 2.5 R {sub ⊕}. We also find a best-fit density-radius relationship ρ ≈ 3 g cm{sup –3} × (R/3 R {sub ⊕}){sup –2.3} for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5 R {sub ⊕} are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.

  2. A STRANGE STAR SCENARIO FOR THE FORMATION OF ECCENTRIC MILLISECOND PULSAR/HELIUM WHITE DWARF BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Long; Li, Xiang-Dong [Department of Astronomy, Nanjing University, Nanjing 210046 (China); Dey, Jishnu; Dey, Mira, E-mail: lixd@nju.edu.cn [Department of Physics, Presidency University, 86/1, College Street, Kolkata 700 073 (India)

    2015-07-01

    According to the recycling scenario, millisecond pulsars (MSPs) have evolved from low-mass X-ray binaries (LMXBs). Their orbits are expected to be circular due to tidal interactions during binary evolution, as observed in most binary MSPs. There are some peculiar systems that do not fit this picture. Three recent examples are the PSRs J2234+06, J1946+3417, and J1950+2414, all of which are MSPs in eccentric orbits but with mass functions compatible with expected He white dwarf (WD) companions. It has been suggested these MSPs may have formed from delayed accretion-induced collapse of massive WDs, or the eccentricity may be induced by dynamical interaction between the binary and a circumbinary disk. Assuming that the core density of accreting neutron stars (NSs) in LMXBs may reach the density of quark deconfinement, which can lead to phase transition from NSs to strange quark stars, we show that the resultant MSPs are likely to have an eccentric orbit, due to the sudden loss of the gravitational mass of the NS during the transition. The eccentricities can be reproduced with a reasonable estimate of the mass loss. This scenario might also account for the formation of the youngest known X-ray binary Cir X–1, which also possesses a low-field compact star in an eccentric orbit.

  3. Transient dynamics of eccentric double emulsion droplets in a simple shear flow

    Science.gov (United States)

    Kim, Sangkyu; Dabiri, Sadegh

    2017-10-01

    We numerically examine the time-dependent behavior of double emulsions in a simple shear flow using finite volume and front-tracking methods. A single inner drop is initially located eccentrically to the outer drop. When the eccentricity is contained within the plane of shear, the inner drop experiences a "revolving" motion within the plane of shear, orbiting about the center of the compound drop while slowly moving outward. The inner drop eventually experiences a limit cycle, where no more outward movement occurs because the distance between the two interfaces is reduced to a thin liquid film for portions of the revolving cycle. In addition, eccentricity in the direction normal to the plane of shear is tested. In this case, the inner droplet undergoes a "drifting" motion, slowly moving perpendicularly to the plane of shear until only a thin layer remains between the two interfaces. Finally, the revolving and drifting motions are simultaneously observed when the in-plane-of-shear eccentricity is included in addition to the off-plane-of-shear eccentricity. The observed behaviors are not qualitatively affected by the inner to outer droplet radii ratio, and are preserved when Re≤5 ,Cao≤0.1 , and Cai<0.2 .

  4. Effect of Strength Eccentricity on Torsional Behaviour of RC Frame Buildings

    Science.gov (United States)

    Rizwan, Shaik Mohammed; Singh, Yogendra

    2012-02-01

    This study attempts to understand the inelastic seismic behaviour of asymmetric multistory RC buildings using non-linear dynamic time history analysis. Both inherently asymmetric and artificially generated eccentric building models were considered. Two categories of artificially generated models were considered. In the first category, groups of mass symmetric systems (MSS) having strength, stiffness and both strength and stiffness eccentricities were considered. In the second category of models, mass eccentricity was introduced in otherwise symmetric models. Building systems were modelled as 3D space frame with lumped plasticity. The response is evaluated using the peak rotational ductility demand of beams of the different frames as measures of their inelastic response. Investigations of first category of artificially generated MSS showed that the response can be better co-related with the strength eccentricity. The results from the second category of systems not designed for torsion indicated that there is significant variation in the beam ductility demands of different frames, whereas systems designed for torsion indicated a shift in the center of strength towards the center of mass and exhibited almost uniform ductility demand in beams of various frames for smaller eccentricities.

  5. Development of a new universal machine device for eccentric shafts processing

    Directory of Open Access Journals (Sweden)

    Михайло Володимирович Маргуліс

    2015-11-01

    Full Text Available The analysis of the existing lathe devices for machining of eccentric details and the reasons for the development of a new universal machine device– a shifting lathe center-have been described in the article. The device design, its operating principle, the main parts functions and elements of the case were described and illustrated One of the most complicated cases of eccentric shaft turning, that is turning design and scheme of the eccentric shaft of precessional harmonic drive with intermediate rolling bodies when the proposed device was used was described in the article. The shifting lathe center can reduce the complexity of the machine tool for turning eccentric shafts configuration. The ability to install the shifting center in the tailstock and headstock of the lathe, and the availability of the leash makes it possible to turn various eccentric parts, conical surfaces, to apply the device to compensate for the emerging taper in cylindrical shafts processing. All the above mentioned makes the device universal. The specific feature of this device is the use of a ball center and the connection of the centering element with the adjusting screw by a fine thread screw, this increasing the precision machining. The protective cover of the device makes it possible to reduce the chance of possible injury from protruding parts of the device, namely the leash and the centering element

  6. Effects of sport massage on limb girth and discomfort associated with eccentric exercise.

    Science.gov (United States)

    Hart, Joseph M; Swanik, C Buz; Tierney, Ryan T

    2005-01-01

    Sport massage is often used to help prepare for exercise, expedite recovery from muscle soreness, and enhance athletic performance. However, the effect of sport massage on recovery from delayed-onset muscle soreness is unknown. To determine the effect of a short sport massage treatment on intramuscular swelling and pain in response to eccentric exercise. We used a 2 x 8 (treatment x time) repeated-measures design to compare triceps surae muscle girth and pain ratings over the 72 hours after eccentric exercise. University research laboratory. Nineteen healthy, college-aged subjects. Delayed-onset muscle soreness was induced with several sets of eccentric triceps surae contractions at 90% of the estimated concentric, 1-repetition maximum weight. Subjects returned on 3 consecutive days after eccentric exercise with a cycle ergometer for active rest treatments. In addition, 1 leg received the sport massage. Girth measurements were taken at 5.08 cm (2 in), 10.16 cm (4 in), 15.24 cm (6 in), and 20.32 cm (8 in) below the knee joint line, and pain was assessed with a visual analog scale before and after all 4 sessions. No interaction was noted between treatment and time for any girth or pain measurements, and no main effect was seen for treatment. Sport massage did not reduce girth or pain in the lower leg after eccentric exercise within 72 hours.

  7. Analysis of scattering wave for a conducting cylinder coated with eccentric plasma

    Science.gov (United States)

    Yin, Bo; Yang, Feng; Hao, Honggang; Li, Changyong

    2013-05-01

    Object coated with plasma has stimulated great interests of many people because of its stealth capability. The study on a conducting cylinder coated with coaxial plasma is very much, but there are little works on a conducting cylinder coated with eccentric plasma. In this article, a model for a conducting cylinder coated with eccentric unmagnetized plasma is set up, the scattering cross section of the object cylinder is studied by adopting the superposition of cylindrical wave functions and the coordinate transformation, where these wave functions are the solutions of Maxwell's equations with boundary conditions in cylindrical coordinates. The results show that the radar cross section for a conducting cylinder coated with eccentric plasma in every direction decrease obviously with an increase of the distance between two eccentric axes, but is almost not impacted by electron-neutral collision frequency of plasma, and the backscattering cross section of the target reduce with the increase of electron density. Comparing with the coaxial model, the backscattering cross section of the eccentric model has a smaller value in a wide frequency band. This is of significance for the target plasma stealth technology in practice.

  8. A Strange Star Scenario for the Formation of Eccentric Millisecond Pulsar/Helium White Dwarf Binaries

    Science.gov (United States)

    Jiang, Long; Li, Xiang-Dong; Dey, Jishnu; Dey, Mira

    2015-07-01

    According to the recycling scenario, millisecond pulsars (MSPs) have evolved from low-mass X-ray binaries (LMXBs). Their orbits are expected to be circular due to tidal interactions during binary evolution, as observed in most binary MSPs. There are some peculiar systems that do not fit this picture. Three recent examples are the PSRs J2234+06, J1946+3417, and J1950+2414, all of which are MSPs in eccentric orbits but with mass functions compatible with expected He white dwarf (WD) companions. It has been suggested these MSPs may have formed from delayed accretion-induced collapse of massive WDs, or the eccentricity may be induced by dynamical interaction between the binary and a circumbinary disk. Assuming that the core density of accreting neutron stars (NSs) in LMXBs may reach the density of quark deconfinement, which can lead to phase transition from NSs to strange quark stars, we show that the resultant MSPs are likely to have an eccentric orbit, due to the sudden loss of the gravitational mass of the NS during the transition. The eccentricities can be reproduced with a reasonable estimate of the mass loss. This scenario might also account for the formation of the youngest known X-ray binary Cir X-1, which also possesses a low-field compact star in an eccentric orbit.

  9. Investigation on coaxial stability of nano-bearing under two axis-deviation perturbations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A spatial cylindrical model on nano-bearing constructed by double-walled carbon nano-tube (DWCNT) is established. Two motion equations are advanced to characterize the eccentric and deflective mode of the nano-bearing, respectively. On the basis of these equations, the coaxial stability of the nano-bearing under two axis-deviation perturbations is investigated. A characteristic parameter λ * governing the coaxial stability of the nano-bearing is determined. The influences of the angular velocity, interlayer spacing and axial length of the nano-bearing on the characteristic parameter λ * are analyzed and discussed in detail. It is found that when the angular velocity or interlayer spacing is smaller than a certain critical value, the parameter λ * keeps negative, and the coaxial stability of the nano-bearing is maintained. However, the axial length has very insignificant influence on λ * . In addition, for the two non-coaxial modes, the eccentric mode occurs more easily than the deflective one. The results of this paper provide a further insight into the coaxial stability of nano-bearing via the spatial model.

  10. New Methods in Non-Perturbative QCD

    Energy Technology Data Exchange (ETDEWEB)

    Unsal, Mithat [North Carolina State Univ., Raleigh, NC (United States)

    2017-01-31

    In this work, we investigate the properties of quantum chromodynamics (QCD), by using newly developing mathematics and physics formalisms. Almost all of the mass in the visible universe emerges from a quantum chromodynamics (QCD), which has a completely negligible microscopic mass content. An intimately related issue in QCD is the quark confinement problem. Answers to non-perturbative questions in QCD remained largely elusive despite much effort over the years. It is also believed that the usual perturbation theory is inadequate to address these kinds of problems. Perturbation theory gives a divergent asymptotic series (even when the theory is properly renormalized), and there are non-perturbative phenomena which never appear at any order in perturbation theory. Recently, a fascinating bridge between perturbation theory and non-perturbative effects has been found: a formalism called resurgence theory in mathematics tells us that perturbative data and non-perturbative data are intimately related. Translating this to the language of quantum field theory, it turns out that non-perturbative information is present in a coded form in perturbation theory and it can be decoded. We take advantage of this feature, which is particularly useful to understand some unresolved mysteries of QCD from first principles. In particular, we use: a) Circle compactifications which provide a semi-classical window to study confinement and mass gap problems, and calculable prototypes of the deconfinement phase transition; b) Resurgence theory and transseries which provide a unified framework for perturbative and non-perturbative expansion; c) Analytic continuation of path integrals and Lefschetz thimbles which may be useful to address sign problem in QCD at finite density.

  11. A finite-element perturbation approach to fluid/rotor interaction in turbomachinery elements. I - Theory. II - Application

    Science.gov (United States)

    Baskharone, E. A.; Hensel, S. J.

    1991-01-01

    The vibrational characteristics of a rotor that is in contact with a fluid in an annular clearance gap are investigated. The disturbance under consideration involves the axis of rotation, and includes a virtual lateral eccentricity, together with a whirling motion around the housing centerline. The fluid reaction components arise from infinitesimally small deformations with varied magnitudes which are experienced by an assembly of finite elements in the rotor-to-housing gap. A perturbation model is presented in which the perturbation equations emerge from the flow-governing equations in their discrete finite-element form. It is concluded that restrictions on the rotor-to-housing gap geometry, or the manner in which the rotor virtual eccentricity occurs are practically nonexisting. This model is used to compute the rotordynamic coefficients of an annular seal. The rotordynamic behavior of a hydraulic seal with a clearance gap depth/length ratio of 0.01 is analyzed under a cylindrical type of rotor whirl and several running speeds.

  12. Perturbativity in the seesaw mechanism

    Directory of Open Access Journals (Sweden)

    Takehiko Asaka

    2016-02-01

    Full Text Available We consider the Standard Model extended by right-handed neutrinos to explain massive neutrinos through the seesaw mechanism. The new fermion can be observed when it has a sufficiently small mass and large mixings to left-handed neutrinos. If such a particle is the lightest right-handed neutrino, its contribution to the mass matrix of active neutrinos needs to be canceled by that of a heavier one. Yukawa couplings of the heavier one are then larger than those of the lightest one. We show that the perturbativity condition gives a severe upper bound on the mixing of the lightest right-handed neutrino, depending on the masses of heavier ones. Models of high energy phenomena, such as leptogenesis, can be constrained by low energy experiments.

  13. World-line perturbation theory

    CERN Document Server

    van Holten, Jan-Willem

    2016-01-01

    The motion of a compact body in space and time is commonly described by the world line of a point representing the instantaneous position of the body. In General Relativity such a world-line formalism is not quite straightforward because of the strict impossibility to accommodate point masses and rigid bodies. In many situations of practical interest it can still be made to work using an effective hamiltonian or energy-momentum tensor for a finite number of collective degrees of freedom of the compact object. Even so exact solutions of the equations of motion are often not available. In such cases families of world lines of compact bodies in curved space-times can be constructed by a perturbative procedure based on generalized geodesic deviation equations. Examples for simple test masses and for spinning test bodies are presented.

  14. Initial conditions for cosmological perturbations

    Science.gov (United States)

    Ashtekar, Abhay; Gupt, Brajesh

    2017-02-01

    Penrose proposed that the big bang singularity should be constrained by requiring that the Weyl curvature vanishes there. The idea behind this past hypothesis is attractive because it constrains the initial conditions for the universe in geometric terms and is not confined to a specific early universe paradigm. However, the precise statement of Penrose’s hypothesis is tied to classical space-times and furthermore restricts only the gravitational degrees of freedom. These are encapsulated only in the tensor modes of the commonly used cosmological perturbation theory. Drawing inspiration from the underlying idea, we propose a quantum generalization of Penrose’s hypothesis using the Planck regime in place of the big bang, and simultaneously incorporating tensor as well as scalar modes. Initial conditions selected by this generalization constrain the universe to be as homogeneous and isotropic in the Planck regime as permitted by the Heisenberg uncertainty relations.

  15. Quantum coherence of cosmological perturbations

    Science.gov (United States)

    Giovannini, Massimo

    2017-11-01

    In this paper, the degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity. The degree of second-order coherence of curvature inhomogeneities (and, more generally, of the scalar modes of the geometry) reproduces faithfully the optical limit. For the vector and tensor fluctuations, the numerical values of the normalized degrees of second-order coherence in the zero time-delay limit are always larger than unity (which is the Poisson benchmark value) but differ from the corresponding expressions obtainable in the framework of the single-mode approximation. General lessons are drawn on the quantum coherence of large-scale cosmological fluctuations.

  16. Cosmological perturbations for imperfect fluids

    CERN Document Server

    Giovannini, Massimo

    2005-01-01

    Interacting fluids, endowed with bulk viscous stresses, are discussed in a unified perspective with the aim of generalizing the treatment of cosmological perturbation theory to the case where both fluctuating decay rates and fluctuating bulk viscosity coefficients are simultaneously present in the relativistic plasma. A gauge-invariant treatment of the qualitatively new phenomena arising in this context is provided. In a complementary approach, faithful gauge-fixed descriptions of the gravitational and hydrodynamical fluctuations are developed and exploited. To deepen the interplay between bulk viscous stresses and fluctuating decay rates, illustrative examples are proposed and discussed both analytically and numerically. Particular attention is paid to the coupled evolution of curvature and entropy fluctuations when, in the relativistic plasma, at least one of the interacting fluids possesses a fluctuating bulk viscosity coefficient. It is argued that this class of models may be usefully employed as an effec...

  17. Initial conditions for cosmological perturbations

    CERN Document Server

    Ashtekar, Abhay

    2016-01-01

    Penrose proposed that the big bang singularity should be constrained by requiring that the Weyl curvature vanishes there. The idea behind this past hypothesis is attractive because it constrains the initial conditions for the universe in geometric terms and is not confined to a specific early universe paradigm. However, the precise statement of Penrose's hypothesis is tied to classical space-times and furthermore restricts only the gravitational degrees of freedom. These are encapsulated only in the tensor modes of the commonly used cosmological perturbation theory. Drawing inspiration from the underlying idea, we propose a quantum generalization of Penrose's hypothesis using the Planck regime in place of the big bang, and simultaneously incorporating tensor as well as scalar modes. Initial conditions selected by this generalization constrain the universe to be as homogeneous and isotropic in the Planck regime \\emph{as permitted by the Heisenberg uncertainty relations}.

  18. Heat shock protein translocation and expression response is attenuated in response to repeated eccentric exercise

    DEFF Research Database (Denmark)

    Vissing, K.; Bayer, M.L.; Overgaard, K.

    2009-01-01

    weeks between bouts, and were compared with a control group (n = 6). Muscle biopsies collected from m. vastus lateralis of both legs prior to and at 3 h, 24 h and 7 days after exercise were quantified for mRNA levels and/or for HSP27, alpha beta-crystallin and inducible HSP70 content in cytosolic....... mRNA levels for HSP70, HSP27 and alpha beta-crystallin were upregulated within approximately two to fourfold ranges at time points 3 and 24 h post-exercise (P ... HSP70 and HSP27 protein content in cytoskeletal fractions were observed exclusively after eccentric exercise (P fold upregulation after first-bout eccentric exercise was attenuated to a an approximately fourfold upregulation after the repeated eccentric exercise bout...

  19. The Pan-Pacific Planet Search. VII. The Most Eccentric Planet Orbiting a Giant Star

    Science.gov (United States)

    Wittenmyer, Robert A.; Jones, M. I.; Horner, Jonathan; Kane, Stephen R.; Marshall, J. P.; Mustill, A. J.; Jenkins, J. S.; Pena Rojas, P. A.; Zhao, Jinglin; Villaver, Eva; Butler, R. P.; Clark, Jake

    2017-12-01

    Radial velocity observations from three instruments reveal the presence of a 4 M Jup planet candidate orbiting the K giant HD 76920. HD 76920b has an orbital eccentricity of 0.856 ± 0.009, making it the most eccentric planet known to orbit an evolved star. There is no indication that HD 76920 has an unseen binary companion, suggesting a scattering event rather than Kozai oscillations as a probable culprit for the observed eccentricity. The candidate planet currently approaches to about four stellar radii from its host star, and is predicted to be engulfed on a ∼100 Myr timescale due to the combined effects of stellar evolution and tidal interactions.

  20. Eccentric Training Improves Ankle Evertor and Dorsiflexor Strength and Proprioception in Functionally Unstable Ankles.

    Science.gov (United States)

    Hanci, Erdal; Sekir, Ufuk; Gur, Hakan; Akova, Bedrettin

    2016-06-01

    The aim of this study was to investigate the effects of a combined eccentric-concentric exercise program of the ankle evertors and dorsiflexors on proprioception in functionally unstable ankles. Thirteen male recreational athletes with unilateral functional ankle instability were admitted to this study. The unaffected opposite ankles were used as controls. The functionnaly unstable ankle of the subjects performed an isokinetic exercise program of the ankle evertors and dorsiflexors in a combined eccentric-concentric mode for 3 days per week for 6 wks. Before and after the isokinetic exercise program, active and passive joint position sense and kinesthesia and isokinetic strength of the ankle joint were evaluated. Active and passive joint position sense error scores for inversion (P proprioceptive acuity of the ankle joint after a 6-wk eccentric-concentric isokinetic training program in functionally unstable ankles.

  1. Implementation of a Reuse Process for Liquid Crystal Displays Using an Eccentric-Form Tool

    Science.gov (United States)

    Pa, Pai-Shan

    2009-01-01

    This study presents a new nanotechnology application involving an ITO thin-film removal reuse process using an eccentric-form negative electrode, offering a fast removal rate from the surface of liquid crystal displays (LCDs). For the precision removal process, a small amount of eccentricity of the negative electrode or a higher rotational speed of the negative electrode corresponds to a higher etching rate for the ITO. A higher flow velocity of the electrolyte and a higher working temperature also correspond to a higher removal rate. The average effect of the eccentricity is better than the effects of a pulsed current, while the current rating need not be prolonged by the off-time. PMID:19865539

  2. Highly eccentric Kozai mechanism and gravitational-wave observation for neutron-star binaries.

    Science.gov (United States)

    Seto, Naoki

    2013-08-09

    The Kozai mechanism for a hierarchical triple system could reduce the merger time of inner eccentric binary emitting gravitational waves (GWs) and has been qualitatively explained with the secular theory that is derived by averaging short-term orbital revolutions. However, with the secular theory, the minimum value of the inner pericenter distance could be excessively limited by the averaging operation. Compared with traditional predictions, the actual evolution of an eccentric inner binary could be accompanied by (i) a higher characteristic frequency of the pulselike GWs around its pericenter passages and (ii) a larger residual eccentricity at its final inspiral phase. These findings would be important for GW astronomy with the forthcoming advanced detectors.

  3. Probabilistic eccentricity bifurcation for stars around shrinking massive black hole binaries

    Science.gov (United States)

    Iwasa, Mao; Seto, Naoki

    2017-12-01

    Based on the secular theory, we discuss the orbital evolution of stars in a nuclear star cluster to which a secondary massive black hole is infalling with vanishing eccentricity. We find that the eccentricities of the stars could show sharp transitions, depending strongly on their initial conditions. By examining the phase-space structure of an associated Hamiltonian, we show that these characteristic behaviours are partly due to a probabilistic bifurcation at a separatrix crossing, resulting from the retrograde apsidal precession by the cluster potential. We also show that separatrix crossings are closely related to realization of a large eccentricity and could be important for astrophysical phenomena such as tidal disruption events or gravitational wave emissions.

  4. Effect of Eccentricity of Load on Critical Force of Thin-Walled Columns CFRP

    Directory of Open Access Journals (Sweden)

    Pawel Wysmulski

    2017-09-01

    Full Text Available The subject of study was a thin-walled C-section made of carbon fiber reinforced polymer (CFRP. Column was subjected to eccentric compression in the established direction. In the computer simulation, the boundary conditions were assumed in the form of articulated support of the sections of the column. Particular studies included an analysis of the effects of eccentricity on the critical force value. The research was conducted using two independent research methods: numerical and experimental. Numerical simulations were done using the finite element method using the advanced system Abaqus®. The high sensitivity of the critical force value corresponding to the local buckling of the channel section to the load eccentricity was demonstrated.

  5. Decreased muscle GLUT-4 and contraction-induced glucose transport after eccentric contractions

    DEFF Research Database (Denmark)

    Kristiansen, S; Asp, Svend; Richter, Erik

    1996-01-01

    Eccentric exercise causes muscle damage and decreased muscle glycogen and glucose transporter isoform (GLUT-4) protein content. We investigated whether the contraction-induced increase in skeletal muscle glucose transport and muscle performance is affected by prior eccentric contractions. The calf...... contractions. EC rats had a significantly lower total GLUT-4 protein content in the white gastrocnemius (GW) muscle (55%) and red gastrocnemius (GR) muscle (34%) compared with muscle from the CT, ST, and CC rats. In contrast, GLUT-1 protein content was approximately twofold higher in the GW muscle in EC rats...... than in CT rats. In the GW and GR muscle, prior eccentric exercise decreased contraction-induced stimulation of glucose transport compared with CT, ST, and CC rats despite no difference in tension development and oxygen uptake among the groups. There was no change in total GLUT-4 content and glucose...

  6. Temporalis muscle hypertrophy and reduced skull eccentricity in Duchenne muscular dystrophy.

    Science.gov (United States)

    Straathof, C S M; Doorenweerd, N; Wokke, B H A; Dumas, E M; van den Bergen, J C; van Buchem, M A; Hendriksen, J G M; Verschuuren, J J G M; Kan, H E

    2014-10-01

    Muscle hypertrophy and muscle weakness are well known in Duchenne muscular dystrophy. Decreased muscle force can have secondary effects on skeletal growth and development such as facial and dental morphology changes. In this study, we quantified temporal muscle thickness, circumference, and eccentricity of the skull and the head on T1-weighted magnetic resonance imaging (MRI) scans of the head of 15 Duchenne muscular dystrophy patients and 15 controls. Average temporal muscle thickness was significantly increased in patients (12.9 ± 5.2 mm) compared to controls (6.8 ± 1.4 mm) (P muscle thickness and skull eccentricity were significantly negatively correlated in patients, and positively in controls. Hypertrophy of the temporal muscles and changes in skull eccentricity appear to occur early in the course of Duchenne muscular dystrophy. Further studies in younger patients are needed to confirm a causal relationship. © The Author(s) 2014.

  7. Impact of the sleeve thickness on the armature eccentricity in a solenoid valve

    Directory of Open Access Journals (Sweden)

    Goraj Robert

    2016-06-01

    Full Text Available Most studies on solenoid valves (SVs assumed that the armature is concentrically positioned in the sleeve. Under this assumption the transversal component of the magnetic force is equal zero. The article presents an analytical calculation model for the estimation of the armature eccentricity. Using this model the eccentricity was calculated as a function of the sleeve thickness and the hydraulic clearance between the armature and the sleeve. After finding the eccentricity also the permeance of the radial air gap was calculated. This permeance has a direct influence on the drop of the magnetomotive force in the magnetic circuit and finally influences also the axial component of the magnetic force. In the article a calculation of both transversal and axial components of the magnetic force was carried out and presented in the appendix to the article.

  8. Prolonged submaximal eccentric exercise is associated with increased levels of plasma IL-6

    DEFF Research Database (Denmark)

    Rohde, Thomas; MacLean, D A; Richter, Erik

    1997-01-01

    To study the relationship between exercise-related muscle proteolysis and the cytokine response, a prolonged eccentric exercise model of one leg was used. Subjects performed two trials [a branched-chain amino acid (BCAA) supplementation and a control trial]. The release of amino acids from muscle...... during and after the eccentric exercise was decreased in the BCAA trial, suggesting a suppression of net muscle protein degradation. The plasma concentrations of interleukin (IL)-6 increased from 0.75 +/- 0.19 (preexercise) to 5.02 +/- 0.96 pg/ml (2 h postexercise) in the control trial and in the BCAA...... supplementation trial from 1.07 +/- 0.41 to 4.15 +/- 1.21 pg/ml. Eccentric exercise had no effect on the concentrations of neutrophils, lymphocytes, CD16+/CD56+, CD4+, CD8+, CD14+/CD38+, lymphocyte proliferative response, or cytotoxic activities. BCAA supplementation reduced the concentration of CD14+/CD38+ cells...

  9. Adaptive strength gains in dystrophic muscle exposed to repeated bouts of eccentric contraction

    Science.gov (United States)

    Call, Jarrod A.; Eckhoff, Michael D.; Baltgalvis, Kristen A.; Warren, Gordon L.

    2011-01-01

    The objective of this study was to determine the functional recovery and adaptation of dystrophic muscle to multiple bouts of contraction-induced injury. Because lengthening (i.e., eccentric) contractions are extremely injurious for dystrophic muscle, it was considered that repeated bouts of such contractions would exacerbate the disease phenotype in mdx mice. Anterior crural muscles (tibialis anterior and extensor digitorum longus) and posterior crural muscles (gastrocnemius, soleus, and plantaris) from mdx mice performed one or five repeated bouts of 100 electrically stimulated eccentric contractions in vivo, and each bout was separated by 10–18 days. Functional recovery from one bout was achieved 7 days after injury, which was in contrast to a group of wild-type mice, which still showed a 25% decrement in electrically stimulated isometric torque at that time point. Across bouts there was no difference in the immediate loss of strength after repeated bouts of eccentric contractions for mdx mice (−70%, P = 0.68). However, after recovery from each bout, dystrophic muscle had greater torque-generating capacity such that isometric torque was increased ∼38% for both anterior and posterior crural muscles at bout 5 compared with bout 1 (P muscles excised from in vivo-tested hindlimbs 14–18 days after bout 5 had greater specific force than contralateral control muscles (12.2 vs. 10.4 N/cm2, P = 0.005) and a 20% greater maximal relaxation rate (P = 0.049). Additional adaptations due to the multiple bouts of eccentric contractions included rapid recovery and/or sparing of contractile proteins, enhanced parvalbumin expression, and a decrease in fiber size variability. In conclusion, eccentric contractions are injurious to dystrophic skeletal muscle; however, the muscle recovers function rapidly and adapts to repeated bouts of eccentric contractions by improving strength. PMID:21960659

  10. Eccentric Torque-Producing Capacity is Influenced by Muscle Length in Older Healthy Adults.

    Science.gov (United States)

    Melo, Ruth C; Takahashi, Anielle C M; Quitério, Robison J; Salvini, Tânia F; Catai, Aparecida M

    2016-01-01

    Considering the importance of muscle strength to functional capacity in the elderly, the study investigated the effects of age on isokinetic performance and torque production as a function of muscle length. Eleven younger (24.2 ± 2.9 years) and 16 older men (62.7 ± 2.5 years) were subjected to concentric and eccentric isokinetic knee extension/flexion at 60 and 120° · s(-1) through a functional range of motion. The older group presented lower peak torque (in newton-meters) than the young group for both isokinetic contraction types (age effect, p torque deficits in the older group were near 30 and 29% for concentric and eccentric contraction, respectively. Concentric peak torque was lower at 120° · s(-1) than at 60° · s(-1) for both groups (angular velocity effect, p torque was the only exercise tested that showed an interaction effect between age and muscle length (p torque responses to the muscle length between groups. Compared with the young group, the eccentric knee extension torque was 22-56% lower in the older group, with the deficits being lower in the shortened muscle length (22-27%) and higher (33-56%) in the stretched muscle length. In older men, the production of eccentric knee strength seems to be dependent on the muscle length. At more stretched positions, older subjects lose the capacity to generate eccentric knee extension torque. More studies are needed to assess the mechanisms involved in eccentric strength preservation with aging and its relationship with muscle length.

  11. Hypertrophic Effects of Concentric vs. Eccentric Muscle Actions: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Schoenfeld, Brad J; Ogborn, Dan I; Vigotsky, Andrew D; Franchi, Martino V; Krieger, James W

    2017-09-01

    Schoenfeld, BJ, Ogborn, DI, Vigotsky, AD, Franchi, MV, and Krieger, JW. Hypertrophic effects of concentric vs. eccentric muscle actions: A systematic review and meta-analysis. J Strength Cond Res 31(9): 2599-2608, 2017-Controversy exists as to whether different dynamic muscle actions produce divergent hypertrophic responses. The purpose of this paper was to conduct a systematic review and meta-analysis of randomized controlled trials comparing the hypertrophic effects of concentric vs. eccentric training in healthy adults after regimented resistance training (RT). Studies were deemed eligible for inclusion if they met the following criteria: (a) were an experimental trial published in an English-language refereed journal; (b) directly compared concentric and eccentric actions without the use of external implements (i.e., blood pressure cuffs) and all other RT variables equivalent; (c) measured morphologic changes using biopsy, imaging (magnetic resonance imaging, computerized tomography, or ultrasound), bioelectrical impedance, and/or densitometry; (d) had a minimum duration of 6 weeks; and (e) used human participants without musculoskeletal injury or any health condition that could directly, or through the medications associated with the management of said condition, be expected to impact the hypertrophic response to resistance exercise. A systematic literature search determined that 15 studies met inclusion criteria. Results showed that eccentric muscle actions resulted in a greater effect size (ES) compared with concentric actions, but results did not reach statistical significance (ES difference = 0.25 ± 0.13; 95% confidence interval: -0.03 to 0.52; p = 0.076). The mean percent change in muscle growth across studies favored eccentric compared with concentric actions (10.0% vs. 6.8, respectively). The findings indicate the importance of including eccentric and concentric actions in a hypertrophy-oriented RT program, as both have shown to be effective in

  12. Achilles tendon of wistar rats treated with laser therapy and eccentric exercise

    Directory of Open Access Journals (Sweden)

    Maria Verônica de Souza

    2015-10-01

    Full Text Available ABSTRACTIntroduction:Both laser therapy and eccentric exercises are used in tendon injuries. However, the association of these physiotherapeutic modalities is yet little investigated.Objective:To evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking on Achilles tendinopathy of Wistar rats.Method:Eighteen Achilles tendon from 15 adult male Wistar rats were used. Tendons were distributed in six groups (laser, eccentric exercise, laser and eccentric exercise, rest, contralateral tendon, and healthy tendon. Unilateral tendinopathy was surgically induced by transversal compression followed by scarification of tendon fibers. The treatments laser therapy (904 nm, 3J/cm² and/or eccentric exercise (downhill walking; 12 m/min; 50 min/day; 15o inclination treadmill began 24 hours after surgery and remained for 20 days. Clinical and biomechanical analyzes were conducted. Achilles tendon was macroscopically evaluated and the transversal diameter measured. Euthanasia was performed 21 days after lesion induction. Tendons of both limbs were collected and frozen at -20°C until biomechanical analysis, on which the characteristic of maximum load (N, stress at ultimate (MPa and maximum extension (mm were analyzed.Results:Swelling was observed within 72 hours postoperative. No fibrous adhesions were observed nor increase in transversal diameter of tendons. Animals with the exercised tendons, but not treated with laser therapy, presented lower (p=0.0000 locomotor capacity. No difference occurred be-tween groups for the biomechanical characteristics maximum load (p=0.4379, stress at ultimate (p=0.4605 and maximum extension (p=0.3820 evaluated, even considering healthy and contralateral tendons.Conclusion:The concomitant use of low-level laser and the eccentric exercise of downhill walking, starting 24 hours after surgically induced tendinopathy, do not result in a tendon with the same biomechanical resistance or elasticity

  13. Re-evaluation of sarcolemma injury and muscle swelling in human skeletal muscles after eccentric exercise.

    Directory of Open Access Journals (Sweden)

    Ji-Guo Yu

    Full Text Available The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2-3 days and 7-8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7-8 days than at 2-3 days post exercise (p<0.05. In contrast, the value of capillary number per fibre area tended to decrease from 2-3 days to 7-8 days post exercise (lower in 5 of the 6 subjects at 7-8 days than at 2-3 days; p<0.05. Thus, the increased fibre size at 7-8 days post exercise was interpreted to reflect fibre swelling. Because the fibre swelling did not appear at the time that DOMS peaked (between 1.5 to 2.5 days post exercise, we concluded that fibre swelling in the soleus muscle is not directly associated with the symptom of DOMS.

  14. Physiological comparison of concentric and eccentric arm cycling in males and females.

    Directory of Open Access Journals (Sweden)

    C Martyn Beaven

    Full Text Available Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC or concentric (CON arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p0.05. In contrast, delta efficiency (ηΔ, as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men>women; p<0.05. Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the high-force, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences.

  15. The relationships of eccentric strength and power with dynamic balance in male footballers.

    Science.gov (United States)

    Booysen, Marc Jon; Gradidge, Philippe Jean-Luc; Watson, Estelle

    2015-01-01

    Unilateral balance is critical to kicking accuracy in football. In order to design interventions to improve dynamic balance, knowledge of the relationships between dynamic balance and specific neuromuscular factors such as eccentric strength and power is essential. Therefore, the aim was to determine the relationships of eccentric strength and power with dynamic balance in male footballers. The Y-balance test, eccentric isokinetic strength testing (knee extensors and flexors) and the countermovement jump were assessed in fifty male footballers (university (n = 27, mean age = 20.7 ± 1.84 years) and professional (n = 23, mean age = 23.0 ± 3.08 years). Spearman Rank Order correlations were used to determine the relationships of eccentric strength and power with dynamic balance. Multiple linear regression, adjusting for age, mass, stature, playing experience and competitive level was performed on significant relationships. Normalised reach score in the Y-balance test using the non-dominant leg for stance correlated with (1) eccentric strength of the non-dominant leg knee extensors in the university group (r = 0.50, P = 0.008) and (2) countermovement jump height in the university (r = 0.40, P = 0.04) and professional (r = 0.56, P = 0.006) football groups, respectively. No relationships were observed between eccentric strength (knee flexors) and normalised reach scores. Despite the addition of potential confounders, the relationship of power and dynamic balance was significant (r = 0.52, P power correlates moderately with dynamic balance on the non-dominant leg in male footballers.

  16. COMPRESSION GARMENTS AND RECOVERY FROM ECCENTRIC EXERCISE: A 31P-MRS STUDY

    Directory of Open Access Journals (Sweden)

    Michael I. Trenell

    2006-03-01

    Full Text Available The low oxidative demand and muscular adaptations accompanying eccentric exercise hold benefits for both healthy and clinical populations. Compression garments have been suggested to reduce muscle damage and maintain muscle function. This study investigated whether compression garments could benefit metabolic recovery from eccentric exercise. Following 30-min of downhill walking participants wore compression garments on one leg (COMP, the other leg was used as an internal, untreated control (CONT. The muscle metabolites phosphomonoester (PME, phosphodiester (PDE, phosphocreatine (PCr, inorganic phosphate (Pi and adenosine triphosphate (ATP were evaluated at baseline, 1-h and 48-h after eccentric exercise using 31P-magnetic resonance spectroscopy. Subjective reports of muscle soreness were recorded at all time points. The pressure of the garment against the thigh was assessed at 1-h and 48-h following exercise. There was a significant increase in perceived muscle soreness from baseline in both the control (CONT and compression (COMP leg at 1-h and 48-h following eccentric exercise (p < 0.05. Relative to baseline, both CONT and COMP showed reduced pH at 1-h (p < 0.05. There was no difference between CONT and COMP pH at 1-h. COMP legs exhibited significantly (p < 0.05 elevated skeletal muscle PDE 1-h following exercise. There was no significant change in PCr/Pi, Mg2+ or PME at any time point or between CONT and COMP legs. Eccentric exercise causes disruption of pH control in skeletal muscle but does not cause disruption to cellular control of free energy. Compression garments may alter potential indices of the repair processes accompanying structural damage to the skeletal muscle following eccentric exercise allowing a faster cellular repair

  17. Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations

    Directory of Open Access Journals (Sweden)

    Martino V. Franchi

    2017-07-01

    Full Text Available Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively; however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT is assumed to produce greater hypertrophy than concentric resistance training (CON RT. Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood.Thus, the present review aims to, (a critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b clarify the molecular mechanisms that may regulate such adaptations.We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.

  18. Ultrasound Changes in Achilles Tendon and Gastrocnemius Medialis Muscle on Squat Eccentric Overload and Running Performance.

    Science.gov (United States)

    Sanz-López, Fernando; Berzosa Sánchez, César; Hita-Contreras, Fidel; Cruz-Diaz, David; Martínez-Amat, Antonio

    2016-07-01

    Sanz-López, F, Berzosa Sánchez, C, Hita-Contreras, F, Cruz-Diaz, D, and Martínez-Amat, A. Ultrasound changes in Achilles tendon and gastrocnemius medialis muscle on squat eccentric overload and running performance. J Strength Cond Res XX(X): 000-000, 2015-Previous studies have proven the adaptation to load in the Achilles tendon and gastrocnemius muscle after different types of exercise, such as running, heel drop training, and a variety of sports. These findings have been applied to improve performance and in the treatment and prevention of overuse injuries. However, the effects that squat performance may have on the Achilles tendon and gastrocnemius muscle are still unknown. Squats are a widely used training exercise that involves calf-muscle activation. Similarly, no reports have been published regarding the adaptation to load of trained and untrained subjects during several consecutive days of running. The purpose of this study was to analyze changes in the Achilles tendon and in the pennation angles of the gastrocnemius medialis after eccentric overload training and within 3 days of running. Twenty healthy males who volunteered for this study were divided into 2 groups. Subjects in the eccentric overload training (ECC) group performed 6 weeks of eccentric overload training (twice weekly, 4 sets of 7 repetitions in a Yoyo squat device) before the running intervention. All participants, ECC and control (CONT) groups, ran on 3 consecutive days. After the eccentric training, an increase in the cross-sectional area of the Achilles tendon and in the pennation angle was observed. As for the running intervention, the behavior of tissues in both groups was similar. These results suggest that eccentric overload training with squats promotes changes in the Achilles tendon and in the pennation angle of the gastrocnemius medialis muscle. Nevertheless, significant changes in the tissue do not appear between the running performance of trained and untrained subjects.

  19. Closed form bound-state perturbation theory

    Directory of Open Access Journals (Sweden)

    Ollie J. Rose

    1980-01-01

    Full Text Available The perturbed Schrödinger eigenvalue problem for bound states is cast into integral form using Green's Functions. A systematic algorithm is developed and applied to the resulting equation giving rise to approximate solutions expressed as functions of the given perturbation parameter. As a by-product, convergence radii for the traditional Rayleigh-Schrödinger and Brillouin-Wigner perturbation theories emerge in a natural way.

  20. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy

    DEFF Research Database (Denmark)

    Beyer, Rikke; Kongsgaard, Mads; Hougs Kjær, Birgitte

    2015-01-01

    BACKGROUND: Previous studies have shown that eccentric training has a positive effect on Achilles tendinopathy, but few randomized controlled trials have compared it with other loading-based treatment regimens. PURPOSE: To evaluate the effectiveness of eccentric training (ECC) and heavy slow...... resistance training (HSR) among patients with midportion Achilles tendinopathy. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 58 patients with chronic (>3 months) midportion Achilles tendinopathy were randomized to ECC or HSR for 12 weeks. Function and symptoms......), and the mean training session compliance rate was 78% in the ECC group and 92% in the HSR group, with a significant difference between groups (P

  1. Whey protein supplementation accelerates satellite cell proliferation during recovery from eccentric exercise

    DEFF Research Database (Denmark)

    Farup, Jean; Rahbek, Stine Klejs; Knudsen, Inge Skovgaard

    2014-01-01

    well investigated. In a comparative human study, we investigated the effect of hydrolyzed whey protein supplementation following eccentric exercise on fiber type-specific SC accumulation. Twenty-four young healthy subjects received either hydrolyzed whey protein + carbohydrate (whey, n = 12) or iso...... of supplementation. In conclusion, whey protein supplementation may accelerate SC proliferation as part of the regeneration or remodeling process after high-intensity eccentric exercise.......Human skeletal muscle satellite cells (SCs) are essential for muscle regeneration and remodeling processes in healthy and clinical conditions involving muscle breakdown. However, the potential influence of protein supplementation on post-exercise SC regulation in human skeletal muscle has not been...

  2. Heat transfer in CO{sub 2} at supercritical pressures in an eccentric annular channel

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yoon-Yeong, E-mail: yybae@kaeri.re.kr

    2013-12-15

    Highlights: • Heat transfer under supercritical pressure in an eccentric annular channel pressure was studied. • The studied geometry was an eccentric annular channel with an eccentricity of 0.33. • The effect of spacer as a turbulence generator was investigated. • The effects of the mass flux, heat flux, and pressure were investigated. • The obtained data were evaluated against the correlation. - Abstract: An experimental investigation of a supercritical heat transfer in an eccentric annular channel was performed using a supercritical heat transfer test facility, SPHINX, at the Korea Atomic Energy Research Institute (KAERI). The eccentric channel was built by placing a 9.5 mm outer diameter heater rod in a 12.5 mm inner diameter tube with an eccentricity of 0.33. The narrowest gap was 1 mm, and the widest gap was 2 mm. The rod was heated indirectly by an imbedded Nickel Chrome heating wire made of NCHW1. Three simple spacers were installed to see their effect, if any, on the heat transfer. The mass fluxes were 400 and 1200 kg/m{sup 2} s, and the heat flux was varied between 30 and 150 kW/m{sup 2} such that the pseudo-critical point was located within the test section as long as possible. When this was not the case, several tests with stepwise increased inlet temperatures were performed so that at least one of them included the pseudo-critical point. The tests were performed at two different pressures of 7.75 and 8.12 MPa to check the pressure effect. The influence of the gap size was clearly seen with the eccentric channel, if not significant. The wall temperatures along the narrowest gap were higher than those along the widest gap as expected, while it was reversed at the end part of the test section. The test results for the eccentric channel were not much different from those for the concentric channel of a similar gap size. As we have seen from the plain tube test, the diameter effect on the heat transfer was also not significant in this test. On the

  3. Effect of Encoder Eccentricity on Rolling Speed Control and Elimination Method

    Directory of Open Access Journals (Sweden)

    Zhao Ren-Tao

    2017-01-01

    Full Text Available Aiming to solve the problems of incremental photoelectric encoder eccentricity in the speed control system of rolling mill, this paper deduces the calculation model of actual speed, and gives a high precision approximation calculation method. Furthermore, the effectiveness and accuracy of the simplified model are verified by the simulation results. The online identification method of eccentricity and initial angle is also given in the paper. In addition, on the basis of continuous model, this article derives from the discrete model of traditional speed measurement scheme based on digital control system. This proposed algorithm has simplicity and excellent application value, and the effectiveness of the algorithm has been verified.

  4. Perturbative spacetimes from Yang-Mills theory

    CERN Document Server

    Luna, Andrés; Nicholson, Isobel; Ochirov, Alexander; O'Connell, Donal; Westerberg, Niclas; White, Chris D.

    2017-04-12

    The double copy relates scattering amplitudes in gauge and gravity theories. In this paper, we expand the scope of the double copy to construct spacetime metrics through a systematic perturbative expansion. The perturbative procedure is based on direct calculation in Yang-Mills theory, followed by squaring the numerator of certain perturbative diagrams as specified by the double-copy algorithm. The simplest spherically symmetric, stationary spacetime from the point of view of this procedure is a particular member of the Janis-Newman-Winicour family of naked singularities. Our work paves the way for applications of the double copy to physically interesting problems such as perturbative black-hole scattering.

  5. Shock wave therapy associated with eccentric strengthening versus isolated eccentric strengthening for Achilles insertional tendinopathy treatment: a double-blinded randomised clinical trial protocol

    OpenAIRE

    Mansur, Nacime Salom?o Barbachan; Faloppa, Fl?vio; Belloti, Jo?o Carlos; Ingham, Sheila J McNeill; Matsunaga, Fabio Teruo; dos Santos, Paulo Roberto Dias; dos Santos, Bruno Schiefer; Carrazzone, Oreste Lemos [UNIFESP; Peixoto, Gabriel; Aoyama, Bruno Takeshi; Tamaoki, Marcel Jun Sugawara [UNIFESP

    2017-01-01

    Background There is no consensus regarding the treatment of Achilles insertional tendinopathies. Eccentric training remains the main choice in the conservative treatment of this illness; however, the good results in the management of non-insertional Achilles tendinopathy were not replicated in the insertional condition. Low energy shock wave therapy has been described as an alternative to these patients, but has yet to be empirically tested. Hypothesis Shock wave therapy, adjunctive to the ec...

  6. Sliding mode predictive guidance for terminal rendezvous in eccentric orbits

    Science.gov (United States)

    Kasaeian, Seyed Aliakbar; Assadian, Nima; Ebrahimi, Masoud

    2017-11-01

    This paper presents a robust guidance algorithm for a chaser spacecraft to rendezvous with a target spacecraft in Earth orbit. The basis of the proposed guidance method is finding an appropriate set of states as close as possible to the current states that would lead the spacecraft to the target in the desired mission time. In order to provide the prediction of states, the relative dynamics equations of motion are solved analytically for the chaser spacecraft rendezvous considering constant acceleration. Although the equations are solved for rendezvous with circular orbit target, it is shown by several simulations that the proposed guidance algorithm is applicable in perturbed elliptical orbits rendezvous as well. The sliding mode method as a robust nonlinear method is utilized as the steering law. The robust steering law tracks the desired states computed by the predictive guidance method. The Lyapunov stability method proves the asymptotic stability of the integrated guidance and steering laws. Because the proposed closed-loop guidance is simple and computationally easy, it is suitable for implementation in real-time applications. Some numerical simulations are conducted to show the performance of the proposed guidance method in different conditions. It is illustrated that compared with other steering laws, the fuel consumption is reduced utilizing the proposed guidance approach. The results reveal that the sliding mode guarantees the tracking of the required states and minimum final errors even in the presence of uncertainties and disturbances.

  7. Enhanced Glycogen Storage of a Subcellular Hot Spot in Human Skeletal Muscle during Early Recovery from Eccentric Contractions

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Farup, Jean; Rahbek, Stine Klejs

    2015-01-01

    content during post-exercise recovery from eccentric contractions. Analysis was completed on five male subjects performing an exercise bout consisting of 15 x 10 maximal eccentric contractions. Carbohydrate-rich drinks were subsequently ingested throughout a 48 h recovery period and muscle biopsies...

  8. Burn-out, Circumferential Film Flow Distribution and Pressure Drop for an Eccentric Annulus with Heated Rod

    DEFF Research Database (Denmark)

    Andersen, P. S.; Jensen, A.; Mannov, G.

    1974-01-01

    Measurements of (1) burn-out, (2) circumferential film flow distribution, and (3) pressure drop in a 17 × 27.2 × 3500 mm concentric and eccentric annulus geometry are presented. The eccentric displacement was varied between 0 and 3 mm. The working fluid was water. Burn-out curves at 70 bar...... flow variation on burn-out is discussed....

  9. Eccentric Viewing Training in the Home Environment: Can It Improve the Performance of Activities of Daily Living?

    Science.gov (United States)

    Vukicevic, Meri; Fitzmaurice, Kerry

    2009-01-01

    Macular degeneration has a severe impact on a person's ability to perform activities of daily living. This study investigated the impact of in-home training in eccentric viewing on near acuity and performance of activities of daily living. The results suggest that eccentric viewing can ameliorate the impact of the loss of vision that is due to…

  10. Static Eccentricity Fault Recognition in Three-Phase Line Start Permanent Magnet Synchronous Motor Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mahdi Karami

    2014-01-01

    Full Text Available This paper is dedicated to investigating static eccentricity in a three-phase LSPMSM. The modeling of LSPMSM with static eccentricity between stator and rotor is developed using finite element method (FEM. The analytical expression for the permeance and flux components of nonuniform air-gap due to static eccentricity fault is discussed. Various indexes for static eccentricity detection using stator current signal of IM and permanent magnet synchronous motor (PMSM are presented. Since LSPMSM is composed of a rotor which is a combination of these two motors, the ability of these features is evaluated for static eccentricity diagnosis in LSPMSM. The simulated stator current signal of LSPMSM in the presence of static eccentricity is analyzed in frequency domain using power spectral density (PSD. It is demonstrated that static eccentricity fault generates a series of low frequency harmonic components in the form of sidebands around the fundamental frequency. Moreover, the amplitudes of these components increase in proportion to the fault severity. According to the mentioned observations, an accurate frequency pattern is specified for static eccentricity detection in three-phase LSPMSM.

  11. Perturbation theory in light-cone quantization

    Energy Technology Data Exchange (ETDEWEB)

    Langnau, Alex [Stanford Univ., CA (United States)

    1992-01-01

    A thorough investigation of light-cone properties which are characteristic for higher dimensions is very important. The easiest way of addressing these issues is by analyzing the perturbative structure of light-cone field theories first. Perturbative studies cannot be substituted for an analysis of problems related to a nonperturbative approach. However, in order to lay down groundwork for upcoming nonperturbative studies, it is indispensable to validate the renormalization methods at the perturbative level, i.e., to gain control over the perturbative treatment first. A clear understanding of divergences in perturbation theory, as well as their numerical treatment, is a necessary first step towards formulating such a program. The first objective of this dissertation is to clarify this issue, at least in second and fourth-order in perturbation theory. The work in this dissertation can provide guidance for the choice of counterterms in Discrete Light-Cone Quantization or the Tamm-Dancoff approach. A second objective of this work is the study of light-cone perturbation theory as a competitive tool for conducting perturbative Feynman diagram calculations. Feynman perturbation theory has become the most practical tool for computing cross sections in high energy physics and other physical properties of field theory. Although this standard covariant method has been applied to a great range of problems, computations beyond one-loop corrections are very difficult. Because of the algebraic complexity of the Feynman calculations in higher-order perturbation theory, it is desirable to automatize Feynman diagram calculations so that algebraic manipulation programs can carry out almost the entire calculation. This thesis presents a step in this direction. The technique we are elaborating on here is known as light-cone perturbation theory.

  12. Bose-Einstein condensation under the cubic-quintic Gross-Pitaevskii equation in radial domains

    Science.gov (United States)

    Luckins, Ellen K.; Van Gorder, Robert A.

    2018-01-01

    We study stationary and quasi-stationary solutions for the cubic-quintic Gross-Pitaevskii equation modeling Bose-Einstein condensates (BECs) in one, two, and three spatial dimensions under the assumption of radial symmetry with the BEC dynamics influenced by a confining potential. We consider both repulsive and attractive cubic interactions - corresponding respectively to repulsive and attractive two-body interactions - under similar frameworks in order to deduce the effects of the potentials in each case. We also carefully consider the role played by the quintic nonlinearity (modeling the strength of inter-atomic coupling) in modifying the solutions arising due to a purely cubic interaction term. In one spatial dimension, we obtain a variety of exact solutions in the zero-potential limit (including new periodic solutions which generalize known soliton solutions) as well as perturbation solutions for small amplitude confining potentials. For more general forms of the confining potential, we rely on numerical simulations, but these agree with the analytical results when the latter are valid. We also consider the limit where the quintic term dominates the cubic term (with such a limit relevant in the study of a Tonks-Girardeau gas). Under the assumption of radial symmetry, we also consider cylindrical (or, cigar-shaped) and spherical BECs. We consider the nonperturbative regime where either the potential or the amplitude of the solutions is large, obtaining various qualitative analytical results. When the kinetic energy term is small (relative to the nonlinearity and the confining potential), we recover the expected Thomas-Fermi approximation for the stationary solutions. Numerical simulations, under a variety of external confining potentials, are then used to understand the role these potentials play on the BEC solution structure for both the attractive and repulsive regimes. This assortment of analytical and numerical results allows us to better understand the

  13. Recycling perturbations of supershot plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Scott, S.D.; McCune, D.C.; Bell, M.G.; Bell, R.; Budny, R.V.; Fredrickson, E.; Grek, B.; Hill, K.W.; Jassby, D.; Jobes, F.; Johnson, D.W.; Johnson, L.C.; Mansfield, H.K.; Park, H.K.; Ramsey, A.T.; Stratton, B.E.; Synakowski, E.J.; Taylor, G.; Towner, H.H.; Zarnstorff, M.C. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Snipes, J.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1993-03-01

    Thermal heat transport in the core (r/a {le} 0.5) of beam-heated TFTR plasmas vanes by more than a factor of five between L-mode and supershot plasmas for the same I{sub p}, B{sub T}, and P{sub b}. Operationally, this variation is strongly correlated with the particle recycling coefficient of the carbon-carbon composite inner bumper limiter. The mechanisms underlying this correlation are not understood. This paper describes studies of the edge ion temperature, which is an important parameter if {tau}{sub E} is controlled by ion temperature gradient driven turbulence. We find that a edge electron temperature scales simply with power per electron, irrespective of the recycling state of the limiter. By contrast, the scaling of edge ion temperature is strongly affected by the recycling state of the limiter. Much higher edge ion temperatures are attained in low-recycling plasmas for the same power per particle. In addition, perturbative studies of recycling effects on transport have been carried out by puffing in large amounts of helium into a supershot plasma. The local core transport coefficients increase on a transport time scale ({approximately}100 ms), much faster than the current relaxation time scale. This suggests that the current profile is not responsible for the favorable energy confinement of supershot plasmas relative to L-mode plasmas.

  14. Recycling perturbations of supershot plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Scott, S.D.; McCune, D.C.; Bell, M.G.; Bell, R.; Budny, R.V.; Fredrickson, E.; Grek, B.; Hill, K.W.; Jassby, D.; Jobes, F.; Johnson, D.W.; Johnson, L.C.; Mansfield, H.K.; Park, H.K.; Ramsey, A.T.; Stratton, B.E.; Synakowski, E.J.; Taylor, G.; Towner, H.H.; Zarnstorff, M.C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Snipes, J.A. (Massachusetts Inst. of Tech., Cambridge, MA (United States))

    1993-03-01

    Thermal heat transport in the core (r/a [le] 0.5) of beam-heated TFTR plasmas vanes by more than a factor of five between L-mode and supershot plasmas for the same I[sub p], B[sub T], and P[sub b]. Operationally, this variation is strongly correlated with the particle recycling coefficient of the carbon-carbon composite inner bumper limiter. The mechanisms underlying this correlation are not understood. This paper describes studies of the edge ion temperature, which is an important parameter if [tau][sub E] is controlled by ion temperature gradient driven turbulence. We find that a edge electron temperature scales simply with power per electron, irrespective of the recycling state of the limiter. By contrast, the scaling of edge ion temperature is strongly affected by the recycling state of the limiter. Much higher edge ion temperatures are attained in low-recycling plasmas for the same power per particle. In addition, perturbative studies of recycling effects on transport have been carried out by puffing in large amounts of helium into a supershot plasma. The local core transport coefficients increase on a transport time scale ([approximately]100 ms), much faster than the current relaxation time scale. This suggests that the current profile is not responsible for the favorable energy confinement of supershot plasmas relative to L-mode plasmas.

  15. Haemorrhagic fevers and ecological perturbations.

    Science.gov (United States)

    Le Guenno, B

    1997-01-01

    Hemorrhagic fever is a clinical and imprecise definition for several different diseases. Their main common point is to be zoonoses. These diseases are due to several viruses which belong to different families. The Flaviviridae have been known for the longest time. They include the Amaril virus that causes yellow fever and is transported by mosquitoes. Viruses that have come to light more recently belong to three other families: Arenaviridae, Bunyaviridae, and Filoviridae. They are transmitted by rodents (hantaviruses and arenaviruses) or from unknown reservoirs (Ebola Marburg). The primary cause of most outbreaks of hemorrhagic fever viruses is ecological disruption resulting from human activities. The expansion of the world population perturbs ecosystems that were stable a few decades ago and facilitates contacts with animals carrying viruses pathogenic to humans. Another dangerous human activity is the development of hospitals with poor medical hygiene. Lassa, Crimean-Congo or Ebola outbreaks are mainly nosocomial. There are also natural environmental changes: the emergence of Sin Nombre in the U.S. resulted from heavier than usual rain and snow during spring 1993 in the Four Corners. Biological industries also present risks. In 1967, collection of organs from monkeys allowed the discovery in Marburg of a new family of viruses, the Filoviridae. Hemorrhagic fever viruses are cause for worry, and the avenues to reduce their toll are still limited.

  16. Cosmological perturbations for imperfect fluids

    Energy Technology Data Exchange (ETDEWEB)

    Giovannini, Massimo [Centro ' Enrico Fermi' , Compendio del Viminale, Via Panisperna 89/A, 00184 Rome (Italy); Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland)

    2005-12-21

    Interacting fluids, endowed with bulk viscous stresses, are discussed in a unified perspective with the aim of generalizing the treatment of cosmological perturbation theory to the case where both fluctuating decay rates and fluctuating bulk viscosity coefficients are simultaneously present in the relativistic plasma. A gauge-invariant treatment of the qualitatively new phenomena arising in this context is provided. In a complementary approach, faithful gauge-fixed descriptions of the gravitational and hydrodynamical fluctuations are developed and exploited. To deepen the interplay between bulk viscous stresses and fluctuating decay rates, illustrative examples are proposed and discussed both analytically and numerically. Particular attention is paid to the coupled evolution of curvature and entropy fluctuations when, in the relativistic plasma, at least one of the interacting fluids possesses a fluctuating bulk viscosity coefficient. It is argued that this class of models may be usefully employed as an effective description of the decay of the inflaton as well as of other phenomena involving imperfect relativistic fluids.

  17. Radial periodic perturbations of the Kepler problem

    Science.gov (United States)

    Fonda, Alessandro; Gallo, Anna Chiara

    2017-11-01

    We consider radial periodic perturbations of a central force field and prove the existence of rotating periodic solutions, whose orbits are nearly circular. The proof is mainly based on the Implicit Function Theorem, and it permits to handle some small perturbations involving the velocity, as well. Our results apply, in particular, to the classical Kepler problem.

  18. Perturbation of operators and approximation of spectrum

    Indian Academy of Sciences (India)

    defined on a suitable subspace of L2(R) can be viewed as a perturbation of differential operator. If we consider the discretized version of this operator, we obtain a bounded operator on l2(Z), which can be seen as a perturbation of the difference operator, up to some scaling and translation by the identity as defined below:.

  19. Tokamak Transport Studies Using Perturbation Analysis

    NARCIS (Netherlands)

    Cardozo, N. J. L.; Dehaas, J. C. M.; Hogeweij, G. M. D.; Orourke, J.; Sips, A.C.C.; Tubbing, B. J. D.

    1990-01-01

    Studies of the transport properties of tokamak plasmas using perturbation analysis are discussed. The focus is on experiments with not too large perturbations, such as sawtooth induced heat and density pulse propagation, power modulation and oscillatory gas-puff experiments. The approximations made

  20. Smooth rank one perturbations of selfadjoint operators

    NARCIS (Netherlands)

    Hassi, Seppo; Snoo, H.S.V. de; Willemsma, A.D.I.

    Let A be a selfadjoint operator in a Hilbert space aleph with inner product [.,.]. The rank one perturbations of A have the form A+tau [.,omega]omega, tau epsilon R, for some element omega epsilon aleph. In this paper we consider smooth perturbations, i.e. we consider omega epsilon dom \\A\\(k/2) for

  1. Does eccentric exercise reduce pain and improve strength in physically active adults with symptomatic lower extremity tendinosis? A systematic review.

    Science.gov (United States)

    Wasielewski, Noah J; Kotsko, Kevin M

    2007-01-01

    To critically review evidence for the effectiveness of eccentric exercise to treat lower extremity tendinoses. Databases used to locate randomized controlled trials (RCTs) included PubMed (1980-2006), CINAHL (1982-2006), Web of Science (1995-2006), SPORT Discus (1980-2006), Physiotherapy Evidence Database (PEDro), and the Cochrane Collaboration Database. Key words included tendon, tendonitis, tendinosis, tendinopathy, exercise, eccentric, rehabilitation, and therapy. The criteria for trial selection were (1) the literature was written in English, (2) the research design was an RCT, (3) the study participants were adults with a clinical diagnosis of tendinosis, (4) the outcome measures included pain or strength, and (5) eccentric exercise was used to treat lower extremity tendinosis. Specific data were abstracted from the RCTs, including eccentric exercise protocol, adjunctive treatments, concurrent physical activity, and treatment outcome. The calculated post hoc statistical power of the selected studies (n = 11) was low, and the average methodologic score was 5.3/10 based on PEDro criteria. Eccentric exercise was compared with no treatment (n = 1), concentric exercise (n = 5), an alternative eccentric exercise protocol (n = 1), stretching (n = 2), night splinting (n = 1), and physical agents (n = 1). In most trials, tendinosis-related pain was reduced with eccentric exercise over time, but only in 3 studies did eccentric exercise decrease pain relative to the control treatment. Similarly, the RCTs demonstrated that strength-related measures improved over time, but none revealed significant differences relative to the control treatment. Based on the best evidence available, it appears that eccentric exercise may reduce pain and improve strength in lower extremity tendinoses, but whether eccentric exercise is more effective than other forms of therapeutic exercise for the resolution of tendinosis symptoms remains questionable.

  2. The recursion relation in Lagrangian perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Rampf, Cornelius, E-mail: rampf@physik.rwth-aachen.de [Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen, D-52056 Aachen (Germany)

    2012-12-01

    We derive a recursion relation in the framework of Lagrangian perturbation theory, appropriate for studying the inhomogeneities of the large scale structure of the universe. We use the fact that the perturbative expansion of the matter density contrast is in one-to-one correspondence with standard perturbation theory (SPT) at any order. This correspondence has been recently shown to be valid up to fourth order for a non-relativistic, irrotational and dust-like component. Assuming it to be valid at arbitrary (higher) order, we express the Lagrangian displacement field in terms of the perturbative kernels of SPT, which are itself given by their own and well-known recursion relation. We argue that the Lagrangian solution always contains more non-linear information in comparison with the SPT solution, (mainly) if the non-perturbative density contrast is restored after the displacement field is obtained.

  3. Intelligent perturbation algorithms for space scheduling optimization

    Science.gov (United States)

    Kurtzman, Clifford R.

    1991-01-01

    Intelligent perturbation algorithms for space scheduling optimization are presented in the form of the viewgraphs. The following subject areas are covered: optimization of planning, scheduling, and manifesting; searching a discrete configuration space; heuristic algorithms used for optimization; use of heuristic methods on a sample scheduling problem; intelligent perturbation algorithms are iterative refinement techniques; properties of a good iterative search operator; dispatching examples of intelligent perturbation algorithm and perturbation operator attributes; scheduling implementations using intelligent perturbation algorithms; major advances in scheduling capabilities; the prototype ISF (industrial Space Facility) experiment scheduler; optimized schedule (max revenue); multi-variable optimization; Space Station design reference mission scheduling; ISF-TDRSS command scheduling demonstration; and example task - communications check.

  4. Functional Relevance of Relative Maintenance of Maximal Eccentric Quadriceps Torque in Healthy Old Adults

    NARCIS (Netherlands)

    Waanders, Jeroen; Beijersbergen, Chantal; Murgia, Alessio; Hortobagyi, Tibor

    2016-01-01

    BACKGROUND: Old referenced to young adults show a relative maintenance of maximal eccentric (RELM) compared to concentric muscle torque: ∼76 and ∼59%, respectively. However, it is unknown if RELM affords functional benefits in old adults. OBJECTIVE: We examined if there is specificity between the

  5. Observational Bias and the Clustering of Distant Eccentric Kuiper Belt Objects

    Science.gov (United States)

    Brown, Michael E.

    2017-08-01

    The hypothesis that a massive Planet Nine exists in the outer solar system on a distant eccentric orbit was inspired by observations showing that the objects with the most distant eccentric orbits in the Kuiper Belt have orbits that are physically aligned, that is, they are clustered in longitude of perihelion and have similar orbital planes. Questions have remained, however, about the effects of observational bias on these observations, particularly on the longitudes of perihelion. Specifically, distant eccentric Kuiper Belt objects (KBOs) tend to be faint and only observable near their perihelia, suggesting that the longitudes of perihelion of the known distant objects could be strongly biased by the limited number of locations in the sky where deep surveys have been carried out. We have developed a method to rigorously estimate the bias in longitude of perihelion for Kuiper Belt observations. We find that the probability that the 10 known KBOs with semimajor axis beyond 230 au are drawn from a population with uniform longitude of perihelion is 1.2%. Combined with the observation that the orbital poles of these objects are also clustered, the overall probability of detecting these two independent clusterings in a randomly distributed sample is 0.025%. While observational bias is clearly present in these observations, it is unlikely to explain the observed alignment of the distant eccentric KBOs.

  6. ON THE FORMATION OF ECCENTRIC MILLISECOND PULSARS WITH HELIUM WHITE-DWARF COMPANIONS

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, John, E-mail: antoniadis@dunlap.utoronto.ca [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada)

    2014-12-20

    Millisecond pulsars (MSPs) orbiting helium white dwarfs (WDs) in eccentric orbits challenge the established binary-evolution paradigm that predicts efficient orbital circularization during the mass-transfer episode that spins up the pulsar. Freire and Tauris recently proposed that these binary MSPs may instead form from the rotationally delayed accretion-induced collapse of a massive WD. However, their hypothesis predicts that eccentric systems preferably host low-mass pulsars and travel with small systemic velocities—in tension with new observational constraints. Here, I show that a substantial growth in eccentricity may alternatively arise from the dynamical interaction of the binary with a circumbinary disk. Such a disk may form from ejected donor material during hydrogen flash episodes, when the neutron star is already an active radio pulsar and tidal forces can no longer circularize the binary. I demonstrate that a short-lived (10{sup 4}-10{sup 5} yr) disk can result in eccentricities of e ≅ 0.01-0.15 for orbital periods between 15 and 50 days. Finally, I propose that, more generally, the disk hypothesis may explain the lack of circular binary pulsars for the aforementioned orbital-period range.

  7. The effects of eccentric exercise on muscle function and proprioception of individuals being overweight and underweight.

    Science.gov (United States)

    Paschalis, Vassilis; Nikolaidis, Michalis G; Theodorou, Anastasios A; Deli, Chariklia K; Raso, Vagner; Jamurtas, Athanasios Z; Giakas, Giannis; Koutedakis, Yiannis

    2013-09-01

    The aim of this study was to estimate the effect of being overweight or underweight on proprioception at rest and after muscle damaging eccentric exercise. Twelve lean, 12 overweight, and 8 underweight female participants performed an eccentric exercise session using the knee extensor muscles of the dominant leg. Muscle damage indices and proprioception were assessed up to 3 days postexercise. The results indicated that proprioception at baseline of the lean individuals was superior to that of the other 2 groups. The overweight individuals exhibited a smaller knee joint reaction angle to release than did the lean group, whereas the underweight individuals exhibited a larger reaction angle to release than did the lean group. After eccentric exercise, proprioception was affected more in the overweight and the underweight groups than in the lean group. The greater exercise-induced muscle damage appeared in the overweight group, and the deficient muscle mass of the underweight participants could explain in part the greater disturbances that appeared in proprioception in these 2 groups than for the lean counterparts. In conclusion, deviating from the normal body mass is associated with significant disturbances in the proprioception of the legs at rest and after participation in activities involving eccentric actions.

  8. A Comparison of Exercise-Induced Muscle Damage Following Maximal Eccentric Contractions in Men and Boys.

    Science.gov (United States)

    Deli, Chariklia K; Fatouros, Ioannis G; Paschalis, Vassilis; Georgakouli, Kalliopi; Zalavras, Athanasios; Avloniti, Alexandra; Koutedakis, Yiannis; Jamurtas, Athanasios Z

    2017-08-01

    Research regarding exercise-induced muscle-damage mainly focuses on adults. The present study examined exercise-induced muscle-damage responses in adults compared with children. Eleven healthy boys (10-12 y) and 15 healthy men (18-45 y) performed 5 sets of 15 maximal eccentric contractions of the knee extensors. Range of motion (ROM), delayed onset muscle soreness (DOMS) during squat and walking, and peak isometric, concentric and eccentric torque were assessed before, post, 24, 48, 72, and 96 hr postexercise. Creatine kinase (CK) activity was assessed before and 72 hr postexercise. Eccentric exercise resulted in DOMS during squat that persisted for up to 96h in men, and 48 hr in boys (p < .05), and DOMS during walking that persisted for up to 72 hr in men, and 48 hr in boys (p < .01). The ROM was lower in both age groups 48 hr postexercise (p < .001). Isometric (p < .001), concentric (p < .01) and eccentric (p < .01) force decreased post, and up to 48 hr postexercise in men. Except for a reduction in isometric force immediately after exercise, no other changes occurred in boys' isokinetic force. CK activity increased in men at 72 hr postexercise compared with pre exercise levels (p = .05). Our data provide further confirmation that children are less susceptible to exercise-induced muscle damage compared with adults.

  9. Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy

    DEFF Research Database (Denmark)

    Kongsgaard, M; Kovanen, V; Aagaard, P

    2009-01-01

    A randomized-controlled single-blind trial was conducted to investigate the clinical, structural and functional effects of peritendinous corticosteroid injections (CORT), eccentric decline squat training (ECC) and heavy slow resistance training (HSR) in patellar tendinopathy. Thirty-nine male...

  10. Eccentric contractions affect muscle membrane phospholipid fatty acid composition in rats.

    Science.gov (United States)

    Helge, J W; Therkildsen, K J; Jørgensen, T B; Wu, B J; Storlien, L H; Asp, S

    2001-09-01

    This study investigated if prior eccentric contractions, and thus mechanical strain and muscle damage, exert an effect on the muscle membrane phospholipid fatty acid composition in rats, and whether a possible effect could be attenuated by dietary supplements. Twenty-three rats were randomised to three groups who received chow with added fish oil (n = 8), vitamin C (n = 8) or no supplement (n = 7). After 3 weeks of feeding, calf muscles on one side were stimulated electrically during anaesthesia causing eccentric contractions. Two days later the white gastrocnemius, a part of the stimulated calf muscle, was excised from both legs. In the muscles stimulated to contract eccentrically, compared to the control muscles, the proportion of arachidonic acid, C20:4,n-6 (17.7 +/- 0.6; 16.4 +/- 0.4% of total fatty acids, respectively) and docosapentanoeic acid, C22:5,n-3 (2.9 +/- 0.1 and 2.7 +/- 0.1% of total fatty acids, respectively) was uniformly higher across groups (P muscle. Thus one severe bout of eccentric contractions modulates the fatty acid composition of the muscle membrane phospholipids when compared to a control leg, and supplemental intake of fish oil or vitamin C did not attenuate this effect.

  11. Therapeutic potential of eccentric exercises for age-related muscle atrophy

    Directory of Open Access Journals (Sweden)

    Jae-Young Lim

    2016-09-01

    Full Text Available Recent studies have focused on evidence-based interventions to prevent mobility decline and enhance physical performance in older adults. Several modalities, in addition to traditional strengthening programs, have been designed to manage age-related functional decline more effectively. In this study, we reviewed the current relevant literatures to assess the therapeutic potential of eccentric exercises for age-related muscle atrophy (sarcopenia. Age-related changes in human skeletal muscle, and their relationship with physical performance, are discussed with reference to in vitro physiologic and human biomechanics studies. An overview of issues relevant to sarcopenia is provided in the context of the recent consensus on the diagnosis and management of the condition. A decline in mobility among the aging population is closely linked with changes in the muscle force–velocity relationship. Interventions based specifically on increasing velocity and eccentric strength can improve function more effectively compared with traditional strengthening programs. Eccentric strengthening programs are introduced as a specific method for improving both muscle force and velocity. To be more effective, exercise interventions for older adults should focus on enhancing the muscle force–velocity relationship. Exercises that can be performed easily, and that utilize eccentric strength (which is relatively spared during the aging process, are needed to improve both muscle force and velocity.

  12. Eccentric hip adduction and abduction strength in elite soccer players and matched controls

    DEFF Research Database (Denmark)

    Thorborg, Kristian; Couppé, C; Petersen, J

    2011-01-01

    Eccentric hip adduction and abduction strength plays an important role in the treatment and prevention of groin injuries in soccer players. Lower extremity strength deficits of less than 10% on the injured side, compared to the uninjured side, have been suggested as the clinical milestone before...

  13. Planet-induced Stellar Pulsations in HAT-P-2's Eccentric System

    Energy Technology Data Exchange (ETDEWEB)

    Wit, Julien de [Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Lewis, Nikole K. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Knutson, Heather A.; Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Fuller, Jim [TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Antoci, Victoria [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Fulton, Benjamin J. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Laughlin, Gregory [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Deming, Drake [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States); Shporer, Avi [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91009 (United States); Cowan, Nicolas B. [Department of Physics, Department of Earth and Planetary Sciences, McGill University, 3550 rue University, Montreal, QC H3A 2A7 (Canada); Agol, Eric [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Burrows, Adam S. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Langton, Jonathan [Department of Physics, Principia College, Elsah, IL 62028 (United States); Showman, Adam P. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2017-02-20

    Extrasolar planets on eccentric short-period orbits provide a laboratory in which to study radiative and tidal interactions between a planet and its host star under extreme forcing conditions. Studying such systems probes how the planet’s atmosphere redistributes the time-varying heat flux from its host and how the host star responds to transient tidal distortion. Here, we report the insights into the planet–star interactions in HAT-P-2's eccentric planetary system gained from the analysis of ∼350 hr of 4.5 μ m observations with the Spitzer Space Telescope . The observations show no sign of orbit-to-orbit variability nor of orbital evolution of the eccentric planetary companion, HAT-P-2 b. The extensive coverage allows us to better differentiate instrumental systematics from the transient heating of HAT-P-2 b’s 4.5 μ m photosphere and yields the detection of stellar pulsations with an amplitude of approximately 40 ppm. These pulsation modes correspond to exact harmonics of the planet’s orbital frequency, indicative of a tidal origin. Transient tidal effects can excite pulsation modes in the envelope of a star, but, to date, such pulsations had only been detected in highly eccentric stellar binaries. Current stellar models are unable to reproduce HAT-P-2's pulsations, suggesting that our understanding of the interactions at play in this system is incomplete.

  14. Age versus size determination of radial variation in wood specific gravity : lessons from eccentrics

    Science.gov (United States)

    G. Bruce Williamson; Michael C. Wiemann

    2011-01-01

    Radial increases in wood specific gravity have been shown to characterize early successional trees from tropical forests. Here, we develop and apply a novel method to test whether radial increases are determined by tree age or tree size. The method compares the slopes of specific gravity changes across a short radius and a long radius of trees with eccentric trunks. If...

  15. EFFECT OF ECCENTRIC EXERCISE PROGRAMME ON PAIN AND GRIP STRENGTH FOR SUBJECTS WITH MEDIAL EPICONDYLITIS

    Directory of Open Access Journals (Sweden)

    Mishra Prashant Akhilesh

    2014-04-01

    Full Text Available Background and Objective: Therapeutic eccentric exercise may provide both a structural and functional benefit during tendinopathy rehabilitation. The objective is to find the effect of eccentric exercises on improvement of pain and grip strength for subjects with Medial Epicondylitis. Method: Pre to post test experimental study design randomized thirty subjects with medial epicondylitis, 15 each into Group A and Group B. Group B subjects were treated with conventional therapy and Eccentric exercises. Group A subjects were treated with conventional therapy. Results: When means of post intervention were compared using Independent ‘t’ between groups there was no statistically significant difference in improvements obtained in VAS scores and grip strength. There was a statistically significant change in means of VAS score and Grip strength when means were analyzed by using Paired‘t’ test and Wilcoxon signed rank test within the groups with positive percentage of change. Conclusion: It is concluded that four weeks of Eccentric Exercise Programme combined with conventional therapy shown significant effect on improving pain and Grip strength, however the improvement obtained has no difference when compared with control conventional treatment for Subjects with Medial Epicondylitis.

  16. Investigation of viscous fluid flow in an eccentrically deposited annulus using CFD methods

    Science.gov (United States)

    Bojko, M.; Kozdera, M.; Kozubkova, M.

    2013-04-01

    The theory of fluid flow in an eccentrically deposited annulus has of great importance especially in the design of sliding bearings (axial, radial). If the geometry is more complex or shaft is deposited eccentrically, then a suitable alternative for design hydrostatic bearing is using ANSYS Fluent, which solves the general three-dimensional viscous fluid flow also in complex geometry. The problem of flow solves in the narrow gap between the cylinders in this paper, when the inner cylinder is stored with a defined eccentricity. The movement of the inner cylinder is composed of two motions (rotation, precession), i.e. rotation around its own axis and move along the circle whose radius is the size of the eccentricity. Addition the pressure gradient is considered in the axial direction. In the introductory section describes the methodology for defining of motions (rotation and precession of the inner cylinder) when the user function (UDF) is created that defines the rotation and move along the circle in C++. The above described methodology of the solution was then applied to the 3D model with a defined pressure drop when the problem was solved as a time-dependent with a time value corresponding to two turns of the internal shaft.

  17. Investigation of viscous fluid flow in an eccentrically deposited annulus using CFD methods

    Directory of Open Access Journals (Sweden)

    Kozubkova M.

    2013-04-01

    Full Text Available The theory of fluid flow in an eccentrically deposited annulus has of great importance especially in the design of sliding bearings (axial, radial. If the geometry is more complex or shaft is deposited eccentrically, then a suitable alternative for design hydrostatic bearing is using ANSYS Fluent, which solves the general three-dimensional viscous fluid flow also in complex geometry. The problem of flow solves in the narrow gap between the cylinders in this paper, when the inner cylinder is stored with a defined eccentricity. The movement of the inner cylinder is composed of two motions (rotation, precession, i.e. rotation around its own axis and move along the circle whose radius is the size of the eccentricity. Addition the pressure gradient is considered in the axial direction. In the introductory section describes the methodology for defining of motions (rotation and precession of the inner cylinder when the user function (UDF is created that defines the rotation and move along the circle in C++. The above described methodology of the solution was then applied to the 3D model with a defined pressure drop when the problem was solved as a time-dependent with a time value corresponding to two turns of the internal shaft.

  18. Methods for determining the effect of flatness deviations, eccentricity and pyramidal errors on angle measurements

    CSIR Research Space (South Africa)

    Kruger, OA

    2000-01-01

    Full Text Available , eccentricity and pyramidal errors of the measuring faces. Deviations in the flatness of angle surfaces have been held responsible for the lack of agreement in angle comparisons. An investigation has been carried out using a small-angle generator...

  19. Effects of Horn Ellipticity and Eccentricity on Neutrino Flux for DUNE

    Science.gov (United States)

    Amador, Eric; Yu, Jaehoon; Lebrun, Paul; Avila, Monica; Lira, Nicholas; Deep Underground Neutrino Experiment Collaboration

    We will simulate the effects of horn ellipticity, eccentricity and current equalizer on our horn focusing system for the Deep Underground Neutrino Experiment (DUNE). The muon neutrino and electron neutrino integrated fluxes will be measured at both Near and Far Detector, and will be compared to its anti-neutrino mode integrated fluxes.

  20. Synthesis of eccentric titania-silica core-shell and composite particles

    NARCIS (Netherlands)

    Demirors, A.F.|info:eu-repo/dai/nl/30483176X; van Blaaderen, A.|info:eu-repo/dai/nl/092946488; Imhof, A.|info:eu-repo/dai/nl/145641600

    2009-01-01

    We describe a novel method to synthesize colloidal particles with an eccentric core-shell structure. Titania-silica core-shell particles were synthesized by silica coating of porous titania particles under Sto¨ber (Sto¨ber et al. J. Colloid Interface Sci. 1968, 26, 62) conditions. We can control

  1. Eccentric hip abductor weakness in patients with symptomatic external snapping hip

    DEFF Research Database (Denmark)

    Jacobsen, Julie Sandell; Thorborg, Kristian; Søballe, K

    2012-01-01

    Symptomatic external snapping hip can be a long-standing condition affecting physical function in younger people between 15-40 years. Gluteal weakness has been suggested to be associated with the condition. The aim of this study was to investigate whether eccentric hip abduction strength....... Eccentric hip abduction strength was 16% lower in patients with external snapping hip compared with healthy matched controls (1.50 ± 0.47 Nm/kg versus 1.82 ± 0.48 Nm/kg, P = 0.01). No other strength differences were measured between patients and controls (P > 0.05). Eccentric hip abductor weakness...... were compared with 13 healthy matched controls in a cross-sectional study design. The mean age of the patients was 25.5 ± 3.4 years and the mean age of the controls was 25.6 ± 2.6 years. Eccentric and isometric strength were assessed with a handheld dynamometer, using reliable test procedures...

  2. Orbital forcing in Pliocene-Pleistocene Mediterranean lacustrine deposits: dominant expression of eccentricity versus precession

    NARCIS (Netherlands)

    Vugt, N. van; Langereis, C.G.; Hilgen, F.J.

    2001-01-01

    Milankovitch forcing of climate is expressed in the sedimentary record as lithological cycles that can have one or more of four typical periods related to precession (21 kyr), obliquity (41 kyr) and eccentricity (100 and 400 kyr). In several Mediterranean continental successions, striking

  3. Effectiveness and feasibility of eccentric and task-oriented strength training in individuals with stroke

    NARCIS (Netherlands)

    Folkerts, Mireille A; Hijmans, Juha M.; Elsinghorst, Anne L.; Mulderij, Yvon; Murgia, Alessio; Dekker, Rienk

    2017-01-01

    BACKGROUND: Strength training can increase function in individuals with stroke. However it is unclear which type of strength training is most effective and feasible. OBJECTIVE: To assess the effect and feasibility of an intervention combining eccentric and task-oriented strength training in

  4. IS ENHANCED-ECCENTRIC RESISTANCE TRAINING SUPERIOR TO TRADITIONAL TRAINING FOR INCREASING ELBOW FLEXOR STRENGTH?

    Directory of Open Access Journals (Sweden)

    Thomas W. Kaminski

    2003-06-01

    Full Text Available Protocols for strengthening muscle are important for fitness, rehabilitation, and the prevention of myotendinous injuries. In trained individuals, the optimal method of increasing strength remains unclear. The purpose of this study was to compare the effects of a traditional method of strengthening with a method that allowed for enhanced-eccentric training, on changes in elbow flexor strength in trained subjects. Thirty-nine (8 male, 31 female trained subjects with normal elbow function participated in this study. Subjects were rank-ordered according to isometric force production and randomly assigned to one of three training groups: control (CONT, traditional concentric/eccentric (TRAD, and concentric/enhanced-eccentric (NEG. The training groups completed 24 training sessions. An evaluator blinded to training group performed all testing. Mixed model ANOVA techniques were used to determine if differences existed in concentric one repetition maximum strength, and isometric force production among groups. Changes in peak and average isokinetic force production were also compared. Type 1 error was maintained at 5%. While both groups improved concentric one repetition maximum (NEG = 15.5%, TRAD = 13.8% neither training group statistically differed from changes demonstrated by the CONT group. Nor did either training group show significant improvements in isometric or isokinetic force production over the CONT group. These results do not support the superiority of enhanced-eccentric training for increasing force production in trained subjects.

  5. Einstein@Home Discovery of a PALFA Millisecond Pulsar in an Eccentric Binary Orbit

    NARCIS (Netherlands)

    Knispel, B.; Lyne, A.G.; Stappers, B.W.; Freire, P.C.C.; Lazarus, P.; Allen, B.; Aulbert, C.; Bock, O.; Bogdanov, S.; Brazier, A.; Camilo, F.; Cardoso, F.; Chatterjee, S.; Cordes, J.M.; Crawford, F.; Deneva, J.S.; Eggenstein, H.B.; Fehrmann, H.; Ferdman, R.; Hessels, J.W.T.; Jenet, F.A.; Karako-Argaman, C.; Kaspi, V.M.; van Leeuwen, J.; Lorimer, D.R.; Lynch, R.; Machenschalk, B.; Madsen, E.; McLaughlin, M.A.; Patel, C.; Ransom, S.M.; Scholz, P.; Siemens, X.; Spitler, L.G.; Stairs, I.H.; Stovall, K.; Swiggum, J.K.; Venkataraman, A.; Wharton, R.S.; Zhu, W.W.

    2015-01-01

    We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 M⊙ and is most likely a

  6. Lower-Bound Calculations of the Bearing Capacity of Eccentrically Loaded Footings in Cohesionless Soil

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Damkilde, Lars; Krabbenhøft, Kristian

    2012-01-01

    . The results are reported as tables and graphs showing the bearing capacity as a function of the eccentricity and surcharge. Normalised interaction diagrams in the vertical force versus moment plane have been produced. The results from the analysis are in reasonable agreement with existing methods for smaller...

  7. Investigating the Effects of Knee Flexion during the Eccentric Heel-Drop Exercise

    Directory of Open Access Journals (Sweden)

    Robert A. Weinert-Aplin, Anthony M.J. Bull, Alison H. McGregor

    2015-06-01

    Full Text Available This study aimed to characterise the biomechanics of the widely practiced eccentric heel-drop exercises used in the management of Achilles tendinosis. Specifically, the aim was to quantify changes in lower limb kinematics, muscle lengths and Achilles tendon force, when performing the exercise with a flexed knee instead of an extended knee. A musculoskeletal modelling approach was used to quantify any differences between these versions of the eccentric heel drop exercises used to treat Achilles tendinosis. 19 healthy volunteers provided a group from which optical motion, forceplate and plantar pressure data were recorded while performing both the extended and flexed knee eccentric heel-drop exercises over a wooden step when barefoot or wearing running shoes. This data was used as inputs into a scaled musculoskeletal model of the lower limb. Range of ankle motion was unaffected by knee flexion. However, knee flexion was found to significantly affect lower limb kinematics, inter-segmental loads and triceps muscle lengths. Peak Achilles load was not influenced despite significantly reduced peak ankle plantarflexion moments (p < 0.001. The combination of reduced triceps lengths and greater ankle dorsiflexion, coupled with reduced ankle plantarflexion moments were used to provide a basis for previously unexplained observations regarding the effect of knee flexion on the relative loading of the triceps muscles during the eccentric heel drop exercises. This finding questions the role of the flexed knee heel drop exercise when specifically treating Achilles tendinosis.

  8. Measuring the Eccentricity of the Earth's Orbit with a Nail and a Piece of Plywood

    Science.gov (United States)

    Lahaye, Thierry

    2012-01-01

    I describe how to obtain a rather good experimental determination of the eccentricity of the Earth's orbit, as well as the obliquity of the Earth's rotation axis, by measuring, over the course of a year, the elevation of the Sun as a function of time during a day. With a very simple "instrument" consisting of an elementary sundial, first-year…

  9. Measuring Eccentric Strength of the Shoulder External Rotators Using a Handheld Dynamometer: Reliability and Validity.

    Science.gov (United States)

    Johansson, Fredrik R; Skillgate, Eva; Lapauw, Mattis L; Clijmans, Dorien; Deneulin, Valentijn P; Palmans, Tanneke; Engineer, Human Kinetic; Cools, Ann M

    2015-07-01

    Shoulder strength assessment plays an important role in the clinical examination of the shoulder region. Eccentric strength measurements are of special importance in guiding the clinician in injury prevention or return-to-play decisions after injury. To examine the absolute and relative reliability and validity of a standardized eccentric strength-measurement protocol for the glenohumeral external rotators. Descriptive laboratory study. Testing environment at the Department of Rehabilitation Sciences and Physiotherapy of Ghent University, Belgium. Twenty-five healthy participants (9 men and 16 women) without any history of shoulder pain were tested by 2 independent assessors using a handheld dynamometer (HHD) and underwent an isokinetic testing procedure. The clinical protocol used an HHD, a DynaPort accelerometer to measure acceleration and angular velocity of testing 30°/s over 90° of range of motion, and a Biodex dynamometer to measure isokinetic activity. Three eccentric strength measurements: (1) tester 1 with the HHD, (2) tester 2 with the HHD, and (3) Biodex isokinetic strength measurement. The intratester reliability was excellent (0.879 and 0.858), whereas the intertester reliability was good, with an intraclass correlation coefficient between testers of 0.714. Pearson product moment correlation coefficients of 0.78 and 0.70 were noted between the HHD and the isokinetic data, showing good validity of this new procedure. Standardized eccentric rotator cuff strength can be tested and measured in the clinical setting with good-to-excellent reliability and validity using an HHD.

  10. The Falcon(TM) eccentric coronary balloon angioplasty catheter : A randomized safety and efficacy study

    NARCIS (Netherlands)

    Qureshi, N; denHeijer, P; vanBoven, AJ; Tio, R; deKam, PJ; Crijns, HJGM

    1997-01-01

    Percutaneous coronary angioplasty (PTCA) is usually performed using concentric shaped balloon catheters with the guidewire passing through the center of the shaft. The Falcon(TM) balloon catheter features a guide wire lumen on the outside of the balloon so that an eccentric balloon catheter profile

  11. Eccentric small-zone ray tracing wavefront aberrometry for refraction in keratoconus.

    Science.gov (United States)

    Fredriksson, Anneli; Behndig, Anders

    2016-11-01

    To compare objective refraction using small-zone eccentric laser ray tracing (LRT) wavefront aberrometry to standard autorefraction in keratoconus (KC), and whether the visual acuities achieved with these refractions differ from corresponding values in healthy eyes. Twenty-nine eyes of 29 patients with KC and 29 eyes of 29 healthy controls were included in this prospective unmasked case-control study. The uncorrected (UCVA) and spectacle-corrected (SCVA) Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuities based on refractions derived from LRT in central and four eccentric zones were compared to those achieved with standard autorefraction. The spherical equivalent (M) and two astigmatic power vectors (C0 and C45) were calculated for all refractions. Pentacam HR ® was used to generate keratometry readings of the corresponding zones. In KC, the refraction from the upper nasal zone rendered a higher SCVA than the standard autorefraction more often than in the controls (p refractions rendered similar SCVA:s in KC. Pentacam HR ® showed higher keratometry readings infero-temporally, but also lower readings supero-nasally, compared to controls. In KC, eccentric LRT measurements gave better SCVA than standard autorefraction more often than in healthy eyes. Eccentric LRT may become a valuable tool in the demanding task of subjective refraction in KC. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  12. The Influence of Mass Loss on the Eccentricity of Double Star Orbits

    Science.gov (United States)

    Docobo, J. A.; Prieto, C.; Ling, J. F.

    In this comunication we study the behaviour of the eccentricity of double star orbits (visual and wide spectroscopic binaries) according to simplified laws of mass loss. Applications to the systems WDS 05245S0224 - HD 35411, WDS 05387S0236 - HD 37468 and WDS 06154S0902 - HD 43362 are included.

  13. On the Mathematical Modeling of Line-Start Permanent Magnet Synchronous Motors under Static Eccentricity

    Directory of Open Access Journals (Sweden)

    Ibrahem Hussein

    2018-01-01

    Full Text Available Line start permanent magnet synchronous motors experience different types of failures, including static eccentricity. The first step in detecting such failures is the mathematical modeling of the motor under healthy and failed conditions. In this paper, an attempt to develop an accurate mathematical model for this motor under static eccentricity is presented. The model is based on the modified winding function method and coupled magnetic circuits approach. The model parameters are calculated directly from the motor winding layout and its geometry. Static eccentricity effects are considered in the motor inductances calculation. The performance of the line start permanent magnet synchronous motor using the developed mathematical model is investigated using MATLAB/SIMULINK® software (2013b, MathWorks, Natick, MA, USA under healthy and static eccentricity condition for different loading values. A finite element method analysis is conducted to verify the mathematical model results, using the commercial JMAG® software (16.0.02n, JSOL Corporation, Tokyo, Japan. The results show a fine agreement between JMAG® and the developed mathematical model simulation results.

  14. A novel optical rotary encoder with eccentricity self-detection ability

    Science.gov (United States)

    Li, Xuan; Ye, Guoyong; Liu, Hongzhong; Ban, Yaowen; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

    2017-11-01

    Eccentricity error is the main error source of optical rotary encoders. Real-time detection and compensation of the eccentricity error is an effective way of improving the accuracy of rotary optical encoders. In this paper, a novel rotary optical encoder is presented to realize eccentricity self-detection. The proposed encoder adopts a spider-web-patterned scale grating as a measuring standard which is scanned by a dual-head scanning unit. Two scanning heads of the dual-head scanning unit, which are arranged orthogonally, have the function of scanning the periodic pattern of the scale grating along the angular and radial directions, respectively. By this means, synchronous measurement of angular and radial displacements of the scale grating is realized. This paper gives the details of the operating principle of the rotary optical encoder, developing and testing work of a prototype. The eccentricity self-detection result agrees well with the result measured by an optical microscope. The experimental result preliminarily proves the feasibility and effectiveness of the proposed optical encoder.

  15. Load eccentricity effects on behavior of circular footings reinforced with geogrid sheets

    Directory of Open Access Journals (Sweden)

    Ehsan Badakhshan

    2015-12-01

    Full Text Available In this paper, an experimental study for an eccentrically loaded circular footing, resting on a geogrid reinforced sand bed, is performed. To achieve this aim, the steel model footing of 120 mm in diameter and sand in relative density of 60% are used. Also, the effects of depth of first and second geogrid layers and number of reinforcement layers (1–4 on the settlement-load response and tilt of footing under various load eccentricities (0 cm, 0.75 cm, 1.5 cm, 2.25 cm and 3 cm are investigated. Test results indicate that ultimate bearing capacity increases in comparison with unreinforced condition. It is observed that when the reinforcements are placed in the optimum embedment depth (u/D = 0.42 and h/D = 0.42, the bearing capacity ratio (BCR increases with increasing load eccentricity to the core boundary of footing, and that with further increase of load eccentricity, the BCR decreases. Besides, the tilt of footing increases linearly with increasing settlement. Finally, by reinforcing the sand bed, the tilt of footing decreases at 2 layers of reinforcement and then increases by increasing the number of reinforcement layers.

  16. Effects of eccentric exercise on trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    ) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40s over 2 days, before, immediately and 24h after eccentric exercise. Surface EMG signals were recorded from four parts of the trapezius during computer work. FINDINGS: EMG amplitude during computer work decreased...... immediately after exercise (Prest time was observed during...... active pause (Prest...

  17. Decreased insulin action on muscle glucose transport after eccentric contractions in rats

    DEFF Research Database (Denmark)

    Asp, S; Richter, Erik

    1996-01-01

    We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physio...

  18. Acute neuromuscular response during eccentric overload protocol by using a mechanical device to increase the load

    Directory of Open Access Journals (Sweden)

    Marcel B Lanza

    2017-11-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n4p375   The aim of this study was to propose a mechanical device that could increase the mechanical load during the entire eccentric (ECC action on a knee flexor machine and to compare the muscular activity when the device was used during a testing protocol. Fifteen physically active women were recruited, and they performed two protocols: control and eccentric overload. Control protocol was performed with concentric (CON and ECC actions with similar load (60% of one repetition maximum whilst eccentric overload protocol consisted of ECC actions with 40% more load than CON actions. Muscular activation was measured using surface electromyography of the biceps femoris (BF and the gastrocnemius medialis (GM muscles. ECC actions presented a higher muscular activation during eccentric overload protocol than control protocol for BF (p = 0.032, but not for the GM (p = 0.439. The mechanical device increased the mechanical load during the ECC muscle action and consequently increased the amplitude of the neural drive to the BF muscle; however, it did not increase the amplitude of the neural drive to the GM muscle.

  19. Strength and endurance training reduces the loss of eccentric hamstring torque observed after soccer specific fatigue.

    Science.gov (United States)

    Matthews, Martyn J; Heron, Kate; Todd, Stefanie; Tomlinson, Andrew; Jones, Paul; Delextrat, Anne; Cohen, Daniel D

    2017-05-01

    To investigate the effect of two hamstring training protocols on eccentric peak torque before and after soccer specific fatigue. Twenty-two university male soccer players. Isokinetic strength tests were performed at 60°/s pre and post fatigue, before and after 2 different training interventions. A 45-min soccer specific fatigue modified BEAST protocol (M-BEAST) was used to induce fatigue. Players were randomly assigned to a 4 week hamstrings conditioning intervention with either a maximum strength (STR) or a muscle endurance (END) emphasis. The following parameters were evaluated: Eccentric peak torque (EccPT), angle of peak torque (APT), and angle specific torques at knee joint angles of 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° and 90°. There was a significant effect of the M-BEAST on the Eccentric torque angle profile before training as well as significant improvements in post-fatigue torque angle profile following the effects of both strength and muscle endurance interventions. Forty-five minutes of simulated soccer activity leads to reduced eccentric hamstring torque at longer muscle lengths. Short-term conditioning programs (4-weeks) with either a maximum strength or a muscular endurance emphasis can equally reduce fatigue induced loss of strength over this time period. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Metabolic demand and muscle damage induced by eccentric cycling of knee extensor and flexor muscles.

    Science.gov (United States)

    Peñailillo, Luis; Guzmán, Nicolás; Cangas, José; Reyes, Alvaro; Zbinden-Foncea, Hermann

    2017-03-01

    The aim of this study was to examine the metabolic demand and extent of muscle damage of eccentric cycling targeting knee flexor (FLEX) and knee extensor (EXT) muscles. Eight sedentary men (23.3 ± 0.7 y) underwent two eccentric cycling sessions (EXT and FLEX) of 30 min each, at 60% of the maximum power output. Oxygen consumption (VO 2 ), heart rate (HR) and rated perceived exertion (RPE) were measured during cycling. Countermovement and squat jumps (CMJ and SJ), muscle flexibility, muscle soreness and pain pressure threshold (PPT) of knee extensor and flexor muscles were measured before, immediately after and 1-4 days after cycling. FLEX showed greater VO 2 (+23%), HR (+14%) and RPE (+18%) than EXT. CMJ and SJ performance decreased similarly after cycling. Muscle soreness increased more after EXT than FLEX and PPT decreased in knee extensor muscles after EXT and decreased in knee flexor muscles after FLEX. Greater loss of muscle flexibility in knee flexor muscles after FLEX was observed. Eccentric cycling of knee flexor muscles is metabolically more demanding than that of knee extensors, however muscle damage induced is similar. Knee flexors experienced greater loss of muscle flexibility possibly due to increased muscle stiffness following eccentric contractions.

  1. Neuromuscular Adaptations to Eccentric Strength Training in Children and Adolescents with Cerebral Palsy

    Science.gov (United States)

    Reid, Siobhan; Hamer, Peter; Alderson, Jacqueline; Lloyd, David

    2010-01-01

    Aim: To determine the neuromuscular outcomes of an eccentric strength-training programme for children and adolescents with cerebral palsy (CP). Method: In this randomised, parallel-group trial with waiting control, 14 participants with CP (six males, eight females; mean age 11y, SD 2y range 9-15y), diagnosed with upper-limb spasticity were…

  2. EXPLORING A 'FLOW' OF HIGHLY ECCENTRIC BINARIES WITH KEPLER

    Energy Technology Data Exchange (ETDEWEB)

    Dong Subo; Katz, Boaz; Socrates, Aristotle [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2013-01-20

    With 16-month of Kepler data, 15 long-period (40-265 days) eclipsing binaries on highly eccentric orbits (minimum e between 0.5 and 0.85) are identified from their closely separated primary and secondary eclipses ({Delta}t{sub I,II} = 3-10 days). These systems confirm the existence of a previously hinted binary population situated near a constant angular momentum track at P(1 - e {sup 2}){sup 3/2} {approx} 15 days, close to the tidal circularization period P{sub circ}. They may be presently migrating due to tidal dissipation and form a steady-state 'flow' ({approx}1% of stars) feeding the close-binary population (few % of stars). If so, future Kepler data releases will reveal a growing number (dozens) of systems at longer periods, following dN/dlgP {proportional_to} P {sup 1/3} with increasing eccentricities reaching e {yields} 0.98 for P {yields} 1000 days. Radial-velocity follow-up of long-period eclipsing binaries with no secondary eclipses could offer a significantly larger sample. Orders of magnitude more (hundreds) may reveal their presence from periodic 'eccentricity pulses', such as tidal ellipsoidal variations near pericenter passages. Several new few-day-long eccentricity-pulse candidates with long periods (P = 25-80 days) are reported.

  3. Eccentric Knee Flexor Strength and Risk of Hamstring Injuries in Rugby Union: A Prospective Study.

    Science.gov (United States)

    Bourne, Matthew N; Opar, David A; Williams, Morgan D; Shield, Anthony J

    2015-11-01

    Hamstring strain injuries (HSIs) represent the most common cause of lost playing time in rugby union. Eccentric knee flexor weakness and between-limb imbalance in eccentric knee flexor strength are associated with a heightened risk of HSIs in other sports; however, these variables have not been explored in rugby union. To determine if lower levels of eccentric knee flexor strength or greater between-limb imbalance in this parameter during the Nordic hamstring exercise are risk factors for HSIs in rugby union. Cohort study; Level of evidence, 2. This prospective study was conducted over the 2014 Super Rugby and Queensland Rugby Union seasons. In total, 178 rugby union players (mean age, 22.6 ± 3.8 years; mean height, 185.0 ± 6.8 cm; mean weight, 96.5 ± 13.1 kg) had their eccentric knee flexor strength assessed using a custom-made device during the preseason. Reports of previous hamstring, quadriceps, groin, calf, and anterior cruciate ligament injuries were also obtained. The main outcome measure was the prospective occurrence of HSIs. Twenty players suffered at least 1 HSI during the study period. Players with a history of HSIs had a 4.1-fold (95% CI, 1.9-8.9; P = .001) greater risk of subsequent HSIs than players without such a history. Between-limb imbalance in eccentric knee flexor strength of ≥15% and ≥20% increased the risk of HSIs by 2.4-fold (95% CI, 1.1-5.5; P = .033) and 3.4-fold (95% CI, 1.5-7.6; P = .003), respectively. Lower eccentric knee flexor strength and other prior injuries were not associated with an increased risk of future HSIs. Multivariate logistic regression revealed that the risk of reinjuries was augmented in players with strength imbalances. Previous HSIs and between-limb imbalance in eccentric knee flexor strength were associated with an increased risk of future HSIs in rugby union. These results support the rationale for reducing imbalance, particularly in players who have suffered a prior HSI, to mitigate the risk of future

  4. THE ACUTE EFFECTS OF CONCENTRIC VERSUS ECCENTRIC MUSCLE FATIGUE ON SHOULDER ACTIVE REPOSITIONING SENSE

    Science.gov (United States)

    2017-01-01

    Purpose/Background Shoulder proprioception is essential in the activities of daily living as well as in sports. Acute muscle fatigue is believed to cause a deterioration of proprioception, increasing the risk of injury. The purpose of this study was to evaluate if fatigue of the shoulder external rotators during eccentric versus concentric activity affects shoulder joint proprioception as determined by active reproduction of position. Study design Quasi-experimental trial. Methods Twenty-two healthy subjects with no recent history of shoulder pathology were randomly allocated to either a concentric or an eccentric exercise group for fatiguing the shoulder external rotators. Proprioception was assessed before and after the fatiguing protocol using an isokinetic dynamometer, by measuring active reproduction of position at 30 ° of shoulder external rotation, reported as absolute angular error. The fatiguing protocol consisted of sets of fifteen consecutive external rotator muscle contractions in either the concentric or eccentric action. The subjects were exercised until there was a 30% decline from the peak torque of the subjects’ maximal voluntary contraction over three consecutive muscle contractions. Results A one-way analysis of variance test revealed no statistical difference in absolute angular error (p > 0.05) between concentric and eccentric groups. Moreover, no statistical difference (p > 0.05) was found in absolute angular error between pre- and post-fatigue in either group. Conclusions Eccentric exercise does not seem to acutely affect shoulder proprioception to a larger extent than concentric exercise. Level of evidence 2b PMID:28515976

  5. An isokinetic eccentric programme for the management of chronic lateral epicondylar tendinopathy.

    Science.gov (United States)

    Croisier, Jean-Louis; Foidart-Dessalle, Marguerite; Tinant, France; Crielaard, Jean-Michel; Forthomme, Bénédicte

    2007-04-01

    Lateral epicondylitis represents a frequent overuse injury. In spite of many conservative treatment procedures, prolonged symptoms and relapse are frequently observed. To compare the outcome of patients performing an isokinetic eccentric training with that of age-, gender-, activity-matched patients receiving a non-strengthening classical rehabilitation. Ninety-two patients with unilateral chronic lateral epicondylar tendinopathy (mean duration of symptoms 8+/-3 months) were assigned either to a control group (n = 46) or to an eccentrically trained group (n = 46). The control group underwent a passive standardised rehabilitation programme that excluded strengthening exercises. In addition to this programme, the trained group also performed eccentric exercises based on the repetitive lengthening of the active musculo-tendinous unit. The latter exercises started with submaximal contraction intensity and slow speed movement. Modalities were progressively intensified (increase in intensity contraction and speed movement) over a long period of treatment. Programme effectiveness was assessed through pain score evaluation, a disability questionnaire, muscle strength measurement and ultrasonographic examination. Compared to the non-strengthening control group, the following observations were made in the eccentrically trained group: (1) a significantly more marked reduction of pain intensity, mainly after one month of treatment; (2) an absence of strength deficit on the involved side through bilateral comparison for the forearm supinator and wrist extensor muscles; (3) an improvement of the tendon image as demonstrated by decreasing thickness and a recovered homogenous tendon structure; and (4) a more marked improvement in disability status during occupational, spare time and sports activities. These results highlight the relevance of implementing isokinetic adapted eccentric training in the management of chronic lateral epicondylar tendinopathy.

  6. Effect of New Zealand blueberry consumption on recovery from eccentric exercise-induced muscle damage.

    Science.gov (United States)

    McLeay, Yanita; Barnes, Matthew J; Mundel, Toby; Hurst, Suzanne M; Hurst, Roger D; Stannard, Stephen R

    2012-07-11

    Exercise-induced muscle damage (EIMD) is accompanied by localized oxidative stress / inflammation which, in the short-term at least, is associated with impaired muscular performance. Dietary antioxidants have been shown to reduce excessive oxidative stress; however, their effectiveness in facilitating recovery following EIMD is not clear. Blueberries demonstrate antioxidant and anti-inflammatory properties. In this study we examine the effect of New Zealand blueberries on EIMD after strenuous eccentric exercise. In a randomized cross-over design, 10 females consumed a blueberry smoothie or placebo of a similar antioxidant capacity 5 and 10 hours prior to and then immediately, 12 and 36 hours after EIMD induced by 300 strenuous eccentric contractions of the quadriceps. Absolute peak and average peak torque across the knee, during concentric, isometric, and eccentric actions were measured. Blood biomarkers of oxidative stress, antioxidant capacity, and inflammation were assessed at 12, 36 and 60 hours post exercise. Data were analyzed using a two-way ANOVA. A significant (p blueberry intervention group. A similar trend was observed for concentric and eccentric strength. An increase in oxidative stress and inflammatory biomarkers was also observed in both treatment groups following EIMD. Although a faster rate of decrease in oxidative stress was observed in the blueberry group, it was not significant (p blueberry smoothie prior to and after EIMD accelerates recovery of muscle peak isometric strength. This effect, although independent of the beverage's inherent antioxidant capacity, appears to involve an up-regulation of adaptive processes, i.e. endogenous antioxidant processes, activated by the combined actions of the eccentric exercise and blueberry consumption. These findings may benefit the sporting community who should consider dietary interventions that specifically target health and performance adaptation.

  7. Metabolic and muscle damage profiles of concentric versus repeated eccentric cycling.

    Science.gov (United States)

    Peñailillo, Luis; Blazevich, Anthony; Numazawa, Hideo; Nosaka, Kazunori

    2013-09-01

    Eccentric cycling is an exercise modality that could elicit multiple health benefits with low metabolic cost, but unaccustomed performance results in significant muscle damage. It is not known whether muscle damage is attenuated when eccentric cycling is repeated; thus, this study compared metabolic and muscle damage responses to concentric (CONC) and two consecutive eccentric (ECC1 and ECC2) cycling bouts. Ten men (28 ± 8 yr) performed each cycling bout for 30 min at 60% of the maximal concentric power output at 60 rpm, with 2 wk between bouts. HR, oxygen consumption (V˙O2), blood lactate (BLa), RPE, and muscle activity (EMG) data were collected during cycling. Maximal voluntary isometric knee extensor (MVC) strength, squat (SJ), countermovement jump (CMJ) height, muscle soreness indicators, and plasma creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Average HR, V˙O2, BLa, and RPE were lower (P < 0.05) during ECC1 than CONC, and EMG amplitude was also lower during ECC1 than CONC. Decreases in MVC, CMJ, and SJ and the increase in muscle soreness were greater (P x0003C; 0.05) after ECC1 than CONC. Increases in creatine kinase were minimal after all bouts. When comparing ECC1 and ECC2, HR and BLa were lower (P < 0.05) during ECC2 than ECC1, and decreases in MVC, CMJ, and SJ and the increase in muscle soreness were greater (P < 0.05) after ECC1 than ECC2. After ECC2, MVC, CMJ, and SJ did not change and no muscle soreness was developed. Eccentric cycling was less metabolically demanding than concentric cycling, and HR and BLa were further reduced during ECC2. Muscle damage is minimal after ECC2 and should not influence the choice to undertake eccentric cycling training.

  8. Effect of deep stripping massage alone or with eccentric resistance on hamstring length and strength.

    Science.gov (United States)

    Forman, Jeffrey; Geertsen, Lisbeth; Rogers, Michael E

    2014-01-01

    Many studies have evaluated the effects of different interventions on hamstring length. However, little research has been conducted on the effects of deep stripping massage strokes (DSMS) alone, or combined with eccentric resistance, on hamstring length and strength. To determine: 1) if DSMS have an effect on hamstring length and strength and 2) if the effects on hamstring length and strength are any different when DSMS are combined with eccentric exercise. 89 Community College students and community members between the ages of 18 and 62 volunteered for the study. Of these, 64 demonstrated tight hamstrings on either one or both sides as defined by supine, passive terminal knee extension of ≤75° and participated in the study. Strength was assessed by pressing the posterior calcaneus into a strain gauge for approximately 5 s while seated with the knee flexed to 90°. On their tighter side, participants were administered longitudinal DSMS during 15, 10-s bouts of eccentric resistance with an elastic resistance band. On their other hamstring, participants were administered 15, 10-s longitudinal DSMS while lying passive. All massage strokes were performed at a depth of 7 out of 10 on a verbal pressure scale index. Afterwards, the hamstring flexibility and strength tests were repeated. Both DSMS with eccentric resistance (10.7%) and DSMS alone (6.3%) resulted in improved (p affected by either treatment. These results suggest that DSMS increases hamstring length in less than 3 min but has no affect on strength. Furthermore, combining DSMS with eccentric resistance produces more hamstring flexibility gains than DSMS alone and does not affect strength. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Effect of New Zealand blueberry consumption on recovery from eccentric exercise-induced muscle damage

    Directory of Open Access Journals (Sweden)

    McLeay Yanita

    2012-07-01

    Full Text Available Abstract Background Exercise-induced muscle damage (EIMD is accompanied by localized oxidative stress / inflammation which, in the short-term at least, is associated with impaired muscular performance. Dietary antioxidants have been shown to reduce excessive oxidative stress; however, their effectiveness in facilitating recovery following EIMD is not clear. Blueberries demonstrate antioxidant and anti-inflammatory properties. In this study we examine the effect of New Zealand blueberries on EIMD after strenuous eccentric exercise. Methods In a randomized cross-over design, 10 females consumed a blueberry smoothie or placebo of a similar antioxidant capacity 5 and 10 hours prior to and then immediately, 12 and 36 hours after EIMD induced by 300 strenuous eccentric contractions of the quadriceps. Absolute peak and average peak torque across the knee, during concentric, isometric, and eccentric actions were measured. Blood biomarkers of oxidative stress, antioxidant capacity, and inflammation were assessed at 12, 36 and 60 hours post exercise. Data were analyzed using a two-way ANOVA. Results A significant (p p = 0.047 interaction effect was seen for peak isometric tension suggesting a faster rate of recovery in the blueberry intervention group. A similar trend was observed for concentric and eccentric strength. An increase in oxidative stress and inflammatory biomarkers was also observed in both treatment groups following EIMD. Although a faster rate of decrease in oxidative stress was observed in the blueberry group, it was not significant (p  Conclusions This study demonstrates that the ingestion of a blueberry smoothie prior to and after EIMD accelerates recovery of muscle peak isometric strength. This effect, although independent of the beverage’s inherent antioxidant capacity, appears to involve an up-regulation of adaptive processes, i.e. endogenous antioxidant processes, activated by the combined actions of the eccentric exercise

  10. Perturbing macroscopic magnetohydrodynamic stability for toroidal plasmas

    Science.gov (United States)

    Comer, Kathryn J.

    We have introduced a new perturbative technique to rapidly explore the dependence of long wavelength ideal magnetohydrodynamic (MHD) instabilities on equilibrium profiles, shaping properties, and wall parameters. Traditionally, these relations are studied with numerical parameter scans using computationally intensive stability codes. Our perturbative technique first finds the equilibrium and stability using traditional methods. Subsequent small changes in the original equilibrium parameters change the stability. We quickly find the new stability with an expansion of the energy principle, rather than with another run of the stability codes. We first semi-analytically apply the technique to the screw pinch after eliminating compressional Alfven wave effects. The screw pinch results validate the approach, but also indicate that allowable perturbations to equilibria with certain features may be restricted. Next, we extend the approach to toroidal geometry using experimental equilibria and a simple constructed equilibrium, with the ideal MHD stability code GATO. Stability properties are successfully predicted from perturbed toroidal equilibria when only the vacuum beyond the plasma is perturbed (through wall parameter variations), rather than the plasma itself. Small plasma equilibrium perturbations to both experimental and simple equilibria result in very large errors to the predicted stability, and valid results are found only over a narrow range of most perturbations. Despite the large errors produced when changing plasma parameters, the wall perturbations revealed two useful applications of this technique. Because the calculations are non-iterative matrix multiplications, the convergence issues that can disrupt a full MHD stability code are absent. Marginal stability, therefore, is much easier to find with the perturbative technique. Also, the perturbed results can be input as the initial guess for the eigenvalue for a full stability code, and improve subsequent

  11. Critical behaviors of gravity under quantum perturbations

    Directory of Open Access Journals (Sweden)

    ZHANG Hongsheng

    2014-02-01

    Full Text Available Phase transition and critical phenomenon is a very interesting topic in thermodynamics and statistical mechanics. Gravity is believed to have deep and inherent relation to thermodynamics. Near the critical point,the perturbation becomes significant. Thus for ordinary matter (governed by interactions besides gravity the critical behavior will become very different if we ignore the perturbations around the critical point,such as mean field theory. We find that the critical exponents for RN-AdS spacetime keep the same values even when we consider the full quantum perturbations. This indicates a key difference between gravity and ordinary thermodynamic system.

  12. The influence of eccentric contractions and stretch on alpha motoneuron excitability in normal subjects and subjects with spasticity.

    Science.gov (United States)

    Rochester, L; Vujnovich, A; Newstead, D; Williams, M

    2001-01-01

    Application of eccentric contractions and muscle stretch are clinically effective in reducing spasticity and increasing ROM (7). This may be explained by a change in the excitability of motoneurons supplying the spastic muscle. Excitability of motoneurons can be indirectly assessed using the H-reflex. Experiments were performed on 20 normal subjects and 17 subjects with spasticity resulting from neurological disorder. Subjects were seated in a secure position and the ankle joint was moved from 30 degrees plantarflexion to 20 degrees dorsiflexion at a velocity of 30 degrees/sec. Sixty eccentric contractions of the triceps surae muscle were performed using a Kin-Com dynamometer (Chattanooga Corp, Tennessee). Two protocols were used: (1) eccentric contractions only, and (2) eccentric contractions with a 5s stretch of the relaxed triceps surae after each contraction. Two sets of 10 H-reflexes were collected from the soleus muscle before (trial 1 & 2) and after (trial 3 & 4) eccentric and eccentric + stretch protocols. The mean peak to peak H-reflex amplitude was calculated for each trial and compared using ANOVA. Eccentric contractions resulted in a significant and maintained increase in the H-reflex in neurological compared to normal subjects (P spasticity resulted in an increase in motoneuron excitability which may assist in corticospinal activation of motoneurons during voluntary movement. The eccentric + stretch protocol, resulted in a decrease in the mean amplitude of H-reflexes in neurological subjects, however, this was not significant. The application of a stretch following eccentric contractions decreased motoneuron excitability and may thus be beneficial to decrease spasticity whilst strengthening muscle.

  13. Shock wave therapy associated with eccentric strengthening versus isolated eccentric strengthening for Achilles insertional tendinopathy treatment: a double-blinded randomised clinical trial protocol.

    Science.gov (United States)

    Mansur, Nacime Salomão Barbachan; Faloppa, Flávio; Belloti, João Carlos; Ingham, Sheila J McNeill; Matsunaga, Fabio Teruo; Santos, Paulo Roberto Dias Dos; Santos, Bruno Schiefer Dos; Carrazzone, Oreste Lemos; Peixoto, Gabriel; Aoyama, Bruno Takeshi; Tamaoki, Marcel Jun Sugawara

    2017-01-27

    There is no consensus regarding the treatment of Achilles insertional tendinopathies. Eccentric training remains the main choice in the conservative treatment of this illness; however, the good results in the management of non-insertional Achilles tendinopathy were not replicated in the insertional condition. Low energy shock wave therapy has been described as an alternative to these patients, but has yet to be empirically tested. Shock wave therapy, adjunctive to the eccentric strengthening protocol, will improve measures of pain and function. Double blind, placebo-controlled, parallel groups, randomised clinical trial. 93 patients with a diagnosis of chronic insertional tendinopathy, referred from primary or secondary healthcare services, will be assessed and enrolled in this study. They will be divided into two groups (randomised by sequentially numbered identical envelopes, which will be administered serially to participants), one containing the combination of low energy shock wave and eccentric exercises, as treatment and the other comprehending the exercises and the placebo treatment (an apparatus placed in the therapeutic head). The assessments will occur in 2, 4, 6, 12 and 24 weeks. Patients will be evaluated primarily by the Victorian Institute of Sport Assessment-Achilles questionnaire and secondarily by the visual analogue scale, Algometry, the American Orthopedic Foot and Ankle Society scale, the Foot and Ankle Outcome Score and the 12-item Short Form Health Survey. We will use comparison of two proportions via relative frequency analysis, the Pearson Correlation the χ2 test and the analysis of variance for statistical analyses. This study intends to demonstrate if the association of the eccentric exercise programme with the shock wave therapy can produce good results regarding the treatment of the Achilles insertional tendinopathy. In an attempt to prevent the high costs and complications associated with the surgical intervention, we will try to

  14. Analysis of PM Magnetization Field Effects on the Unbalanced Magnetic Forces due to Rotor Eccentricity in BLDC Motors

    Directory of Open Access Journals (Sweden)

    S. Mahdiuon-Rad

    2013-08-01

    Full Text Available This paper investigates both static and dynamic eccentricities in single phase brushless DC (BLDC motors and analyzes the effect of the PM magnetization field on unbalanced magnetic forces acting on the rotor. Three common types of PM magnetization field patterns including radial, parallel and sinusoidal magnetizations are considered. In both static and dynamic eccentricities, harmonic components of the unbalanced magnetic forces on the rotor are extracted and analyzed. Based on simulation results, the magnetization fields that produce the lowest and highest unbalanced magnetic forces are determined in rotor eccentricity conditions.

  15. Plantar flexor muscle architecture changes as a result of eccentric exercise in patients with Achilles tendinosis.

    Science.gov (United States)

    Crill, Matthew T; Berlet, Gregory; Hyer, Christopher

    2014-12-01

    Eccentric training for Achilles tendinosis (AT) has been reported to significantly improve patient symptoms. There has been no biomechanical explanation on the mechanism for specific rehabilitation technique. The purpose of this study was to determine changes in muscle architecture that occurred as a result of Achilles tendinosis injury and a subsequent eccentric rehabilitation program. Twenty-five patients (age, 53.3 ± 17.5 years) diagnosed with AT participated in 6 weeks of rehabilitation. Specific exercises for the ankle plantar flexors consisted of maximal load eccentric muscle action using 3 sets of 15 repetitions. Patients also completed a protocol for AT, which consisting of traditional rehabilitation. Medial gastrocnemius (GM) and lateral gastrocnemius (GL) muscle fascicle length and thickness were measured with ultrasound at 2-week intervals from initial treatment day to the end of 6 weeks of rehabilitation. Medial gastrocnemius fascicle length increased (45.1 ± 10.5 mm to 51.4 ± 10.5 mm; P = .22) between the initial day of rehabilitation and after 6 weeks of rehabilitation. But, GM thickness (16.3 ± 3.5 mm to 16.8 ± 2.0 mm), GL fascicle length (47.2 ± 10.0 mm to 47.1 ± 7.4 mm), and GL thickness (14.9 ± 5.2 mm to 14.4 ± 2.7 mm) did not change as a result of rehabilitation. A 6-week eccentric-biased exercise increased the GM muscle fascicle length by 12%, but GM thickness, GL fascicle length, and GL thickness did not change as a result of rehabilitation. Eccentric training for the treatment of AT is well recognized, but the mechanism of action has not been previously reported. A 6-week eccentric training protocol increased the GM muscle fascicle length by 12%, and this correlated with improvement in a validated patient outcome scoring system. Further study is warranted to determine a predictive relationship between improvement of GM fascicle length and outcome scores. Therapeutic, Level IV: Case series. © 2014 The Author(s).

  16. The orbits of subdwarf-B + main-sequence binaries. III. The period-eccentricity distribution

    Science.gov (United States)

    Vos, J.; Østensen, R. H.; Vučković, M.; Van Winckel, H.

    2017-09-01

    Context. The predicted orbital-period distribution of the subdwarf-B (sdB) population is bi-modal with peaks at short (500 days) periods. Observationally, many short-period sdB systems are known, but only few wide sdB binaries have been studied in detail. Based on a long-term monitoring programme the wide sdB sample has been increased, discovering an unexpected positive correlation between the eccentricity and orbital period. Aims: In this article we present the orbital solution and spectral analysis of four new systems, BD-7°5977, EC 11031-1348, TYC 2084-448-1 and TYC 3871-835-1, and update the orbital solution of PG 1104+243. Using the whole sample of wide sdB binaries, we aim to find possible correlations between orbital and spectral properties. The ultimate goal is to improve theoretical models of Roche-lobe overflow. Methods: High-resolution spectroscopic time series were obtained to determine the RVs of both the sdB and main sequence (MS) components. Literature photometry was used to construct the spectral-energy distributions, which were fitted with atmosphere models to determine the surface gravities and temperatures of both components in all systems. Spectral parameters of the cool companion were verified using the GSSP code. Furthermore the amount of accreted mass was estimated. Results: Orbital parameters matching the earlier observed period-eccentricity relation were found for three systems, while TYC 2084-448-1 is found to have a lower eccentricity than expected from the period-eccentricity trend indicated by the other systems. Based on new observations, the orbit of PG 1104+243 has a small but significant eccentricity of 0.04 ± 0.02, matching that of the other systems with similar periods. Furthermore, a positive correlation between accreted mass and orbital period was found, as well as a possible relation between the initial mass-ratio and the final period-eccentricity. Conclusions: The wide sdB-binary sample shows interesting possible correlations

  17. Factors contributing to lower metabolic demand of eccentric compared with concentric cycling.

    Science.gov (United States)

    Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

    2017-10-01

    This study compared muscle-tendon behavior, muscle oxygenation, and muscle activity between eccentric and concentric cycling exercise at the same work output to investigate why metabolic demand is lower during eccentric cycling than with concentric cycling. Eleven untrained men (27.1 ± 7.0 y) performed concentric cycling (CONC) and eccentric cycling (ECC) for 10 min (60 rpm) at 65% of the maximal concentric cycling power output (191 ± 45 W) 4 wk apart. During cycling, oxygen consumption (V̇o 2 ), heart rate (HR), vastus lateralis (VL) tissue total hemoglobin (tHb), and oxygenation index (TOI) were recorded, and muscle-tendon behavior was assessed using ultrasonography. The surface electromyogram (EMG) was recorded from VL, vastus medialis (VM), rectus femoris (RF), and biceps femoris (BF) muscles, and cycling torque and knee joint angle during each revolution were also recorded. Average V̇o 2 (-65 ± 7%) and HR (-35 ± 9%) were lower and average TOI was greater (16 ± 1%) during ECC than CONC, but tHb was similar between bouts. Positive and negative cycling peak crank torques were greater (32 ± 21 and 48 ± 24%, respectively) during ECC than CONC, but muscle-tendon unit and fascicle and tendinous tissue length changes during pedal revolutions were similar between CONC and ECC. VL, VM, RF, and BF peak EMG amplitudes were smaller (24 ± 15, 22 ± 18, 16 ± 17, and 18 ± 9%, respectively) during ECC than CONC. These results suggest that the lower metabolic cost of eccentric compared with concentric cycling was due mainly to a lower level of muscle activation per torque output. NEW & NOTEWORTHY This study shows that lower oxygen consumption of eccentric compared with concentric cycling at the same workload is explained by lower muscle activity of agonist and antagonist muscles during eccentric compared with during concentric cycling. Copyright © 2017 the American Physiological Society.

  18. Cosmological perturbations in teleparallel Loop Quantum Cosmology

    CERN Document Server

    Haro, Jaime

    2013-01-01

    Cosmological perturbations in Loop Quantum Cosmology (LQC) could be studied from two totally different ways. The first one, called holonomy corrected LQC, is performed in the Hamiltonian framework, where the Asthekar connection is replaced by a suitable sinus function (holonomy correction), in order to have a well-defined quantum analogue. The alternative approach is based in the fact that isotropic LQC could be also obtained as a particular case of teleparallel $F(T)$ gravity (teleparallel LQC). Then, working in the Lagrangian framework and using the well-know perturbation equations in $F(T)$ gravity, we have obtained, in teleparallel LQC, the equations for scalar and tensor perturbations, and the corresponding Mukhanov-Sasaki equations. For scalar perturbations, our equation only differs from the one obtained by holonomy corrections in the velocity of sound, leading both formulations, essentially to the same scale invariant power spectrum when a matter-dominated universe is considered. However for tensor pe...

  19. Nonlinearly Perturbed Birth-Death-Type Models

    OpenAIRE

    Silvestrov, Dmitrii; Petersson, Mikael; Hössjer, Ola

    2016-01-01

    Asymptotic expansions for stationary and conditional quasi-stationary distributions of nonlinearly perturbed birth-death-type semi-Markov models are presented. Applications to models of population growth, epidemic spread and population genetics are discussed.

  20. 't Hooft loops and perturbation theory

    CERN Document Server

    De Forcrand, Philippe; Noth, D; Forcrand, Philippe de; Lucini, Biagio; Noth, David

    2005-01-01

    We show that high-temperature perturbation theory describes extremely well the area law of SU(N) spatial 't Hooft loops, or equivalently the tension of the interface between different Z_N vacua in the deconfined phase. For SU(2), the disagreement between Monte Carlo data and lattice perturbation theory for sigma(T)/T^2 is less than 2%, down to temperatures O(10) T_c. For SU(N), N>3, the ratios of interface tensions, (sigma_k/sigma_1)(T), agree with perturbation theory, which predicts tiny deviations from the ratio of Casimirs, down to nearly T_c. In contrast, individual tensions differ markedly from the perturbative expression. In all cases, the required precision Monte Carlo measurements are made possible by a simple but powerful modification of the 'snake' algorithm.

  1. On perturbation of eigenvalues embedded at thresholds in a two ...

    Indian Academy of Sciences (India)

    Abstract. We present some results on the perturbation of eigenvalues embedded at thresholds in a two channel model Hamiltonian with a small off-diagonal perturbation. Examples are given of the various types of behavior of the eigenvalue under perturbation.

  2. Primordial magnetic fields from metric perturbations

    CERN Document Server

    Maroto, A L

    2001-01-01

    We study the amplification of electromagnetic vacuum fluctuations induced by the evolution of scalar metric perturbations at the end of inflation. Such perturbations break the conformal invariance of Maxwell equations in Friedmann-Robertson-Walker backgrounds and allow the growth of magnetic fields on super-Hubble scales. We estimate the strength of the fields generated by this mechanism on galactic scales and compare the results with the present bounds on the galactic dynamo seed fields.

  3. Noise Perturbation Improves Supervised Speech Separation

    Science.gov (United States)

    2014-02-01

    perturb a noise segment, we first apply short-time Fourier transform (STFT) to derive noise spectrogram, where a frame length of 20 ms and a frame...In addition, we show HIT−FA rate for voiced and unvoiced intervals in Table 4 and Table 5 respectively. We find that frequency perturbation is...effective for both voiced and unvoiced intervals. While classification accuracy and HIT−FA rate evaluate the estimated binary masks, STOI directly compares

  4. Simplifying quantum double Hamiltonians using perturbative gadgets

    OpenAIRE

    Koenig, Robert

    2009-01-01

    Perturbative gadgets were originally introduced to generate effective k-local interactions in the low-energy sector of a 2-local Hamiltonian. Extending this idea, we present gadgets which are specifically suited for realizing Hamiltonians exhibiting non-abelian anyonic excitations. At the core of our construction is a perturbative analysis of a widely used hopping-term Hamiltonian. We show that in the low-energy limit, this Hamiltonian can be approximated by a certain ordered p...

  5. Nonequilibrium perturbation theory for complex scalar fields

    OpenAIRE

    Lawrie, I. D.; McKernan, D. B.

    1996-01-01

    Real-time perturbation theory is formulated for complex scalar fields away from thermal equilibrium in such a way that dissipative effects arising from the absorptive parts of loop diagrams are approximately resummed into the unperturbed propagators. Low order calculations of physical quantities then involve quasiparticle occupation numbers which evolve with the changing state of the field system, in contrast to standard perturbation theory, where these occupation numbers are frozen at their ...

  6. Tuning Leaky Nanocavity Resonances - Perturbation Treatment

    OpenAIRE

    Shlafman, Michael; Bayn, Igal; Salzman, Joseph

    2010-01-01

    Adiabatic frequency tuning of finite-lifetime-nanocavity electromagnetic modes affects also their quality-factor (Q). Perturbative Q change resulting from (real) frequency tuning, is a controllable parameter. Here, the influence of dielectric constant modulation (DCM) on cavity resonances is presented, by first order perturbation analysis for a 3D cavity with radiation losses. Semi-analytical expressions for DCM induced cavity mode frequency and Q changes are derived. The obtained results are...

  7. Alternative perturbation approaches in classical mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Raya, Alfredo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Blvd. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2005-11-01

    We discuss two alternative methods, based on the Lindstedt-Poincare technique, for the removal of secular terms from the equations of perturbation theory. We calculate the period of an anharmonic oscillator by means of both approaches and show that one of them is more accurate for all values of the coupling constant. We believe that present discussion and comparison may be a suitable exercise for teaching perturbation theory in advanced undergraduate courses on classical mechanics.

  8. Tuning Leaky Nanocavity Resonances - Perturbation Treatment

    CERN Document Server

    Shlafman, Michael; Salzman, Joseph

    2010-01-01

    Adiabatic frequency tuning of finite-lifetime-nanocavity electromagnetic modes affects also their quality-factor (Q). Perturbative Q change resulting from (real) frequency tuning, is a controllable parameter. Here, the influence of dielectric constant modulation (DCM) on cavity resonances is presented, by first order perturbation analysis for a 3D cavity with radiation losses. Semi-analytical expressions for DCM induced cavity mode frequency and Q changes are derived. The obtained results are in good agreement with numerical calculations.

  9. Histomorphometric analysis of the Achilles tendon of Wistar rats treated with laser therapy and eccentric exercise

    Directory of Open Access Journals (Sweden)

    Maria V. de Souza

    2015-12-01

    Full Text Available Abstract: Low-level laser therapy is recommended for the treatment of tendinopathies despite the contradictory results related to the ideal dose of energy, wavelength and time of application. This study aimed to assess the effects of laser therapy and eccentric exercise on tendinopathy of the Achilles tendon of Wistar rats. Forty-eight adult male rats were randomly distributed into four groups (L= laser; E= eccentric exercise; LE = laser and eccentric exercise; and R= rest. Laser therapy (904nm/3J/cm2 and/or eccentric exercise (downhill walking; 15o incline treadmill; 12m/min; 50min/day was started 24h after induction of unilateral tendinopathy and remained for 20 days. At 3, 7, 14 and 21 days after lesion induction, three rats from each group were euthanized and the tendons were collected for histological and morphometric analyses. There was no difference among groups or among times for the characteristics hemorrhage (p=0.4154, fibrinous adhesion formation (p=0.0712, and organization of collagen fibers (p=0.2583 and of the connective tissue (p=0.1046. For these groups, regardless of the time, eccentric exercise led to epitenon thickening (p=0.0204, which was lower in the group treated with laser therapy. Histological analysis revealed differences (p=0.0032 in the number of inflammatory cells over time. They were more numerous in the group that only exercised. This result was confirmed by morphometric analysis, which showed a significant interaction (groups x time for this characteristic. Eccentric exercise increased (p=0.0014 the inflammatory infiltrate over time (3 and 21 days. However, association with laser therapy reduced inflammatory reaction. On the other hand, the combination of the treatments increased angiogenesis in morphometric (p=0.0000 and histological (p=0.0006 analyses compared with the other groups, while the isolated application of low-level laser reduced this characteristic over time. Animals maintained at rest presented the

  10. The advanced eccentricity and broken cage diagnostic method for medium voltage induction motors

    Directory of Open Access Journals (Sweden)

    Janda Žarko

    2012-01-01

    Full Text Available In the paper the comparative diagnostics of medium voltage induction motors has been presented. The methods employed are the motor current signature analysis (MCSA and the axial leakage flux spectral analysis. All presented test procedures have been conducted on partially loaded motors, one without fault and the other with fault. Rated parameters of case study motors are 6 kV and 3.15 MW, and both motors are installed in one combined steam power plant. The reliable broken rotor bars detection and existence of static eccentricity have been demonstrated. The new method for combined fault detection has also been announced. The combined fault under scope is the simultaneous existence of broken rotor bars and static eccentricity. The proposed combined fault detection method is based upon axial leakage flux spectral analysis, especially in the vicinity of the double fundamental frequency. The existence of three broken rotor bars has been confirmed after physical rotor cage examination.

  11. Dynamic Response of Bridge Subjected to Eccentrically Moving Flexible Vehicle: A Semianalytical Approach

    Directory of Open Access Journals (Sweden)

    R. Lalthlamuana

    2014-01-01

    Full Text Available Dynamic response of a single span bridge subjected to moving flexible vehicles has been studied using a semianalytical approach. The eccentricity of vehicle path giving rise to torsional motion of the bridge has been incorporated in the approach. The bridge surface irregularity has been considered as the nonhomogeneous process in spatial domain. A closed form expression has been derived to generate response samples corresponding to each input of roughness profile to form an ensemble. Thereafter, averaging across the ensemble has been carried out at each time step to determine mean and standard deviation of bridge and vehicle response. Further, dynamic amplification factor (DAF of the bridge response has been obtained for several combinations of bridge-vehicle parameters. The study reveals that structural bending modes of vehicle can significantly reduce dynamic response of the bridge. The eccentricity of vehicle path and flexural/torsional rigidity ratios plays a significant role in dynamic amplification of bridge response.

  12. Spatial frequency tuning functions and contrast sensitivity at different eccentricities in the visual field

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.W.; Aine, C.J.; Flynn, E.R.; Wood, C.C.

    1996-07-01

    The human luminance spatial frequency contrast sensitivity function (CSF) has been well studied using psychophysical measurements by detecting spatial frequency (SF) grating patterns at threshold. Threshold CSFs at different eccentricities have proven to be quite useful in both basic and clinical vision research. However, near threshold, the CSF is measured at a linear area of the saturating contrast-response curve. In contrast, most of our everyday vision may be at suprathreshold levels, and thus may function most of the time at the nonlinear area of the contrast-response curve. In this study, in order to better characterize the CSF at normal contrast levels, we measured the SF tuning functions as well as the CR functions at different suprathreshold contrast levels and different eccentricities of the visual field using noninvasive MEG techniques. In this study, in addition to peak analysis, we have developed more reliable averaged power analysis methods where the average power can be calculated from the entire waveforms.

  13. Detecting eccentricity faults in a PMSM in non-stationary conditions

    Directory of Open Access Journals (Sweden)

    Javier Rosero García

    2012-01-01

    Full Text Available Permanent magnet alternating current machines are being widely used in applications demanding high and rugged performance, such as industrial automation and the aerospace and automotive industries. This paper presents a study of a permanent magnet synchronous machine (PMSM running in eccentricity; these machines’ condition monitoring and fault detection would provide added value and they are also assuming growing importance. This paper investigates the effect of eccentricity faults on PMSM motors’ current spectrum with a view to developing an effective condition-monitoring scheme using two-dimensional (2-D finite element analysis (FEA. Stator current induced harmonics were investigated for fault conditions and advanced signal analysis involved continuous and discrete wavelet transforms. Simulation and experimental results are presented to substantiate that the proposed method worked over a wide speed range for motor operation and that it provided an effective tool for diagnosing PMSM operating condition.

  14. Stress intensity factors of eccentric cracks in bi-materials plate under mode I loading

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, A. E. [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Batu Pahat, Johor (Malaysia)

    2015-05-15

    Bi-material plates were generally used to joint electronic devices or mechanical components requiring dissimilar materials to be attached. During services, mechanical failure can be occurred due to the formation of cracks at the interfacial joint or away from the centre. Generally, linear elastic fracture mechanics approach is used to characterize these cracks based on stress intensity factors (SIF). Based on the literature survey, the SIFs for the central cracks were easily available. However, the SIFs for eccentric cracks were difficult to obtain. Therefore, this paper presented the SIFs for eccentric cracks subjected to mode I tension loading. Three important parameters were used such as relative crack depth, a/L, relative offset distance, b/L and elastic mismatch, E{sub 1}/E{sub 2} or α. It was found that such parameters significantly affected the characteristic of SIFs and it was depend on the location of cracks.

  15. Eccentric contractions affect muscle membrane phospholipid fatty acid composition in rats

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff; Therkildsen, K J; Jørgensen, T B

    2001-01-01

    This study investigated if prior eccentric contractions, and thus mechanical strain and muscle damage, exert an effect on the muscle membrane phospholipid fatty acid composition in rats, and whether a possible effect could be attenuated by dietary supplements. Twenty-three rats were randomised...... muscle, was excised from both legs. In the muscles stimulated to contract eccentrically, compared to the control muscles, the proportion of arachidonic acid, C20:4,n-6 (17.7 +/- 0.6; 16.4 +/- 0.4% of total fatty acids, respectively) and docosapentanoeic acid, C22:5,n-3 (2.9 +/- 0.1 and 2.7 +/- 0.......1% of total fatty acids, respectively) was uniformly higher across groups (P acids) compared to the control leg (38.2 +/- 0...

  16. Apocenter Glow in Eccentric Debris Disks: Implications for Fomalhaut and Epsilon Eridani

    Science.gov (United States)

    Pan, Margaret; Nesvold, Erika R.; Kuchner, Marc J.

    2016-01-01

    Debris disks often take the form of eccentric rings with azimuthal asymmetries in surface brightness. Such disks are often described as showing pericenter glow, an enhancement of the disk brightness in regions nearest the central star. At long wavelengths, however, the disk apocenters should appear brighter than their pericenters: in the long-wavelength limit, we find that the apocenter pericenter flux ratio scales as 1 + e for disk eccentricity e. We produce new models of this apocenter glow to explore its causes and wavelength dependence and study its potential as a probe of dust grain properties. Based on our models, we argue that several far-infrared and (sub)millimeter images of the Fomalhaut and Epsilon Eridani debris rings obtained with Herschel, JCMT, SHARC II, ALMA, and ATCA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks dust grain properties and size distributions.

  17. Apocenter Glow in Eccentric Debris Disks: Implications for Fomalhaut and ɛ Eridani

    Science.gov (United States)

    Pan, Margaret; Nesvold, Erika R.; Kuchner, Marc J.

    2016-11-01

    Debris disks often take the form of eccentric rings with azimuthal asymmetries in surface brightness. Such disks are often described as showing “pericenter glow,” an enhancement of the disk brightness in regions nearest the central star. At long wavelengths, however, the disk apocenters should appear brighter than their pericenters: in the long-wavelength limit, we find that the apocenter/pericenter flux ratio scales as 1+e for disk eccentricity e. We produce new models of this “apocenter glow” to explore its causes and wavelength dependence and study its potential as a probe of dust grain properties. Based on our models, we argue that several far-infrared and (sub)millimeter images of the Fomalhaut and ɛ Eridani debris rings obtained with Herschel, JCMT, SHARC II, ALMA, and ATCA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks’ dust grain properties and size distributions.

  18. Highly eccentric hip-hop solutions of the 2 N-body problem

    Science.gov (United States)

    Barrabés, Esther; Cors, Josep M.; Pinyol, Conxita; Soler, Jaume

    2010-02-01

    We show the existence of families of hip-hop solutions in the equal-mass 2 N-body problem which are close to highly eccentric planar elliptic homographic motions of 2 N bodies plus small perpendicular non-harmonic oscillations. By introducing a parameter ɛ, the homographic motion and the small amplitude oscillations can be uncoupled into a purely Keplerian homographic motion of fixed period and a vertical oscillation described by a Hill type equation. Small changes in the eccentricity induce large variations in the period of the perpendicular oscillation and give rise, via a Bolzano argument, to resonant periodic solutions of the uncoupled system in a rotating frame. For small ɛ≠0, the topological transversality persists and Brouwer’s fixed point theorem shows the existence of this kind of solutions in the full system.

  19. Detecting eccentricity faults in a PMSM in non-stationary conditions

    Directory of Open Access Journals (Sweden)

    Javier Rosero García

    2012-04-01

    Full Text Available Permanent magnet alternating current machines are being widely used in applications demanding high and rugged performance, such as industrial automation and the aerospace and automotive industries. This paper presents a study of a permanent magnet synchronous machine (PMSM running in eccentricity; these machines’ condition monitoring and fault detection would provide added value and they are also assuming growing importance. This paper investigates the effect of eccentricity faults on PMSM motors’ current spectrum with a view to developing an effective condition-monitoring scheme using two-dimensional (2-D finite element analysis (FEA. Stator current induced harmonics were investigated for fault conditions and advanced signal analysis involved continuous and discrete wavelet transforms. Simulation and experimental results are presented to substantiate that the proposed method worked over a wide speed range for motor operation and that it provided an effective tool for diagnosing PMSM operating condition.

  20. Local NSAID infusion inhibits satellite cell proliferation in human skeletal muscle after eccentric exercise

    DEFF Research Database (Denmark)

    Mikkelsen, U R; Langberg, H; Helmark, I C

    2009-01-01

    Despite the widespread consumption of nonsteroidal anti-inflammatory drugs (NSAIDs), the influence of these drugs on muscle satellite cells is not fully understood. The aim of the present study was to investigate the effect of a local NSAID infusion on satellite cells after unaccustomed eccentric...... exercise in vivo in human skeletal muscle. Eight young healthy males performed 200 maximal eccentric contractions with each leg. An NSAID was infused via a microdialysis catheter into the vastus lateralis muscle of one leg (NSAID leg) before, during, and for 4.5 h after exercise, with the other leg working...... cells (CD68(+) or CD16(+) cells) was not significantly increased in either of the legs 8 days after exercise and was unaffected by the NSAID. The main finding in the present study was that the NSAID infusion for 7.5 h during the exercise day suppressed the exercise-induced increase in the number...

  1. Nonorthogonality and κ-Dependence Eccentricity of Polarized Electromagnetic Waves in CPT-Even Lorentz Violation

    Directory of Open Access Journals (Sweden)

    Thiago Prudêncio

    2017-01-01

    Full Text Available We discuss the modified Maxwell action of a KF-type Lorentz symmetry breaking theory and present a solution of Maxwell equations derived in the cases of linear and elliptically polarized electromagnetic waves in the vacuum of CPT-even Lorentz violation. We show in this case that the Lorentz violation has the effect of changing the amplitude of one component of the magnetic field, while leaving the electric field unchanged, leading to nonorthogonal propagation of electromagnetic fields and dependence of the eccentricity on κ-term. Further, we exhibit numerically the consequences of this effect in the cases of linear and elliptical polarization, in particular, the regimes of nonorthogonality of the electromagnetic wave fields and the eccentricity of the elliptical polarization of the magnetic field with dependence on the κ-term.

  2. CLIMATE PATTERNS OF HABITABLE EXOPLANETS IN ECCENTRIC ORBITS AROUND M DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuwei; Hu, Yongyun [Laboratory for Climate and Ocean-Atmosphere Sciences, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871 China (China); Tian, Feng, E-mail: yyhu@pku.edu.cn [Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084 (China)

    2014-08-10

    Previous studies show that synchronous rotating habitable exoplanets around M dwarfs should have an ''eyeball'' climate pattern—a limited region of open water on the day side and ice on the rest of the planet. However, exoplanets with nonzero eccentricities could have spin-orbit resonance states different from the synchronous rotation state. Here, we show that a striped-ball climate pattern, with a global belt of open water at low and middle latitudes and ice over both polar regions, should be common on habitable exoplanets in eccentric orbits around M dwarfs. We further show that these different climate patterns can be observed by future exoplanet detection missions.

  3. Compact planetary systems perturbed by an inclined companion. II. Stellar spin-orbit evolution

    Energy Technology Data Exchange (ETDEWEB)

    Boué, Gwenaël; Fabrycky, Daniel C., E-mail: boue@imcce.fr [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)

    2014-07-10

    The stellar spin orientation relative to the orbital planes of multiplanet systems is becoming accessible to observations. Here, we analyze and classify different types of spin-orbit evolution in compact multiplanet systems perturbed by an inclined outer companion. Our study is based on classical secular theory, using a vectorial approach developed in a separate paper. When planet-planet perturbations are truncated at the second order in eccentricity and mutual inclination, and the planet-companion perturbations are developed at the quadrupole order, the problem becomes integrable. The motion is composed of a uniform precession of the whole system around the total angular momentum, and in the rotating frame, the evolution is periodic. Here, we focus on the relative motion associated with the oscillations of the inclination between the planet system and the outer orbit and of the obliquities of the star with respect to the two orbital planes. The solution is obtained using a powerful geometric method. With this technique, we identify four different regimes characterized by the nutation amplitude of the stellar spin axis relative to the orbital plane of the planets. In particular, the obliquity of the star reaches its maximum when the system is in the Cassini regime where planets have more angular momentum than the star and where the precession rate of the star is similar to that of the planets induced by the companion. In that case, spin-orbit oscillations exceed twice the inclination between the planets and the companion. Even if the mutual inclination is only ≅ 20°, this resonant case can cause the spin-orbit angle to oscillate between perfectly aligned and retrograde values.

  4. Increased residual force enhancement in older adults is associated with a maintenance of eccentric strength.

    Directory of Open Access Journals (Sweden)

    Geoffrey A Power

    Full Text Available Despite an age-related loss of voluntary isometric and concentric strength, muscle strength is well maintained during lengthening muscle actions (i.e., eccentric strength in old age. Additionally, in younger adults during lengthening of an activated skeletal muscle, the force level observed following the stretch is greater than the isometric force at the same muscle length. This feature is termed residual force enhancement (RFE and is believed to be a combination of active and passive components of the contractile apparatus. The purpose of this study was to provide an initial assessment of RFE in older adults and utilize aging as a muscle model to explore RFE in a system in which isometric force production is compromised, but structural mechanisms of eccentric strength are well-maintained. Therefore, we hypothesised that older adults will experience greater RFE compared with young adults. Following a reference maximal voluntary isometric contraction (MVC of the dorsiflexors in 10 young (26.1 ± 2.7 y and 10 old (76.0 ± 6.5 y men, an active stretch was performed at 15°/s over a 30° ankle joint excursion ending at the same muscle length as the reference MVCs (40° of plantar flexion. Any additional torque compared with the reference MVC therefore represented RFE. In older men RFE was ~2.5 times greater compared to young. The passive component of force enhancement contributed ~37% and ~20% to total force enhancement, in old and young respectively. The positive association (R(2 = 0.57 between maintained eccentric strength in old age and RFE indicates age-related mechanisms responsible for the maintenance of eccentric strength likely contributed to the observed elevated RFE. Additionally, as indicated by the greater passive force enhancement, these mechanisms may be related to increased muscle series elastic stiffness in old age.

  5. Therapeutic potential of eccentric exercises for age-related muscle atrophy

    OpenAIRE

    Lim, Jae-Young

    2016-01-01

    Recent studies have focused on evidence-based interventions to prevent mobility decline and enhance physical performance in older adults. Several modalities, in addition to traditional strengthening programs, have been designed to manage age-related functional decline more effectively. In this study, we reviewed the current relevant literatures to assess the therapeutic potential of eccentric exercises for age-related muscle atrophy (sarcopenia). Age-related changes in human skeletal muscle, ...

  6. Autonomous distributed LQR/APF control algorithms for CubeSat swarms manoeuvring in eccentric orbits

    OpenAIRE

    Palacios, L.; Ceriotti, Matteo; Radice, G.

    2013-01-01

    Spacecraft formation flying has shown to be promising approach to enhance mission capabilities. Nevertheless, formation flying presents several control challenges which escalate as the numbers of elements in the formation is increased. The objective of this paper is to develop decentralised control algorithms to regulate the station-keeping, reconfiguration and collision avoidance of spacecraft in formation around eccentric reference orbits using the combination of a Linear Quadratic Regulato...

  7. Experimental And FE Analysis Of Eccentric Loaded Symmetrical And Unsymmetrical Bolted Joint With Bolt Pretension

    OpenAIRE

    Pranav R. Pimpalkar; Prof. S. D. Khamankar

    2014-01-01

    This paper presents experimental and FE analysis of eccentric loaded bolted joint under symmetric and unsymmetrical bolt system with consider bolt pretension. A cad model of a bolted joint has been developed using modeling software PROE5.0 and FE analysis was carried out by using ANSYSWORKBENCH12.0.stress analysis has been carried out by varying bolt pattern of bolted joint for predict maximum heavily loaded bolt. Experimental work was conducted to measure maximum shear strengt...

  8. Vitamin D2 Supplementation Amplifies Eccentric Exercise-Induced Muscle Damage in NASCAR Pit Crew Athletes

    Directory of Open Access Journals (Sweden)

    David C. Nieman

    2013-12-01

    Full Text Available This study determined if 6-weeks vitamin D2 supplementation (vitD2, 3800 IU/day had an influence on muscle function, eccentric exercise-induced muscle damage (EIMD, and delayed onset of muscle soreness (DOMS in National Association for Stock Car Auto Racing (NASCAR NASCAR pit crew athletes. Subjects were randomized to vitD2 (n = 13 and placebo (n = 15, and ingested supplements (double-blind for six weeks. Blood samples were collected and muscle function tests conducted pre- and post-study (leg-back and hand grip dynamometer strength tests, body weight bench press to exhaustion, vertical jump, 30-s Wingate test. Post-study, subjects engaged in 90 min eccentric-based exercise, with blood samples and DOMS ratings obtained immediately after and 1- and 2-days post-exercise. Six weeks vitD2 increased serum 25(OHD2 456% and decreased 25(OHD3 21% versus placebo (p < 0.001, p = 0.036, respectively, with no influence on muscle function test scores. The post-study eccentric exercise bout induced EIMD and DOMS, with higher muscle damage biomarkers measured in vitD2 compared to placebo (myoglobin 252%, 122% increase, respectively, p = 0.001; creatine phosphokinase 24 h post-exercise, 169%, 32%, p < 0.001, with no differences for DOMS. In summary, 6-weeks vitD2 (3800 IU/day significantly increased 25(OHD2 and decreased 25(OHD3, had no effect on muscle function tests, and amplified muscle damage markers in NASCAR pit crew athletes following eccentric exercise.

  9. Effect Analysis of Design Variables on the Disc in a Double-Eccentric Butterfly Valve

    OpenAIRE

    Kang, Sangmo; Kim, Da-Eun; Kim, Kuk-Kyeom; Kim, Jun-Oh

    2014-01-01

    We have performed a shape optimization of the disc in an industrial double-eccentric butterfly valve using the effect analysis of design variables to enhance the valve performance. For the optimization, we select three performance quantities such as pressure drop, maximum stress, and mass (weight) as the responses and three dimensions regarding the disc shape as the design variables. Subsequently, we compose a layout of orthogonal array (L16) by performing numerical simulations on the flow an...

  10. A Test of the High-eccentricity Migration Scenario for Close-in Planets

    Science.gov (United States)

    Giacalone, Steven; Matsakos, Titos; Königl, Arieh

    2017-11-01

    In the high-eccentricity migration (HEM) scenario, close-in planets reach the vicinity of the central star on high-eccentricity orbits that become circularized—with a concomitant decrease in the semimajor axis—through a tidal interaction with the star. Giant planets that arrive with periastron distances that are smaller than the Roche limit a R lose their gaseous envelopes, resulting in an inner edge to the surviving planets’ distribution. The observational evidence for this effect, while extensive, is nonetheless somewhat ambiguous because of the effect of tidal orbital decay. Here, we consider another key prediction of the HEM scenario—the existence of a spatial eccentricity gradient near the location where the circularization time becomes comparable to the planet’s age for typical parameters. Previous studies have already found evidence for this gradient and demonstrated that its properties are consistent with the circularization process being dominated by tidal dissipation in the planet (encapsulated by the tidal quality factor {Q}{{p}}{\\prime }). Our work extends these treatments by constructing explicit model distributions for comparison with the data and by carrying out backward-in-time integrations using observed system parameters. We show that circularization generally occurs outside the distribution’s inner edge (which defines the boundary of the so-called sub-Jovian desert) and that typically {Q}{{p}}{\\prime }≈ {10}6 in the circularization zone (to within a factor of 3). We also find tentative evidence for an eccentricity gradient in lower-mass planets, indicating that formation through HEM may be relevant down to Neptune scales.

  11. An Eccentric Binary Millisecond Pulsar with a Helium White Dwarf Companion in the Galactic field

    Science.gov (United States)

    Antoniadis, John; Kaplan, David L.; Stovall, Kevin; Freire, Paulo C. C.; Deneva, Julia S.; Koester, Detlev; Jenet, Fredrick; Martinez, Jose G.

    2016-10-01

    Low-mass white dwarfs (LMWDs) are believed to be exclusive products of binary evolution, as the universe is not old enough to produce them from single stars. Because of the strong tidal forces operating during the binary interaction phase, the remnant systems observed today are expected to have negligible eccentricities. Here, we report on the first unambiguous identification of an LMWD in an eccentric (e = 0.13) orbit around the millisecond pulsar PSR J2234+0511, which directly contradicts this picture. We use our spectra and radio-timing solution (derived elsewhere) to infer the WD temperature ({T}{{eff}}=8600+/- 190 K), and peculiar systemic velocity relative to the local standard of rest (≃ 31 km s-1). We also place model-independent constraints on the WD radius ({R}{{WD}}={0.024}-0.002+0.004 {R}⊙ ) and surface gravity ({log} g={7.11}-0.16+0.08 dex). The WD and kinematic properties are consistent with the expectations for low-mass X-ray binary evolution and disfavor a dynamic three-body formation channel. In the case of the high eccentricity being the result of a spontaneous phase transition, we infer a mass of ˜1.60 M ⊙ for the pulsar progenitor, which is too low for the quark-nova mechanism proposed by Jiang et al., and too high for the scenario of Freire & Tauris, in which a WD collapses into a neutron star via a rotationally delayed accretion-induced collapse. We find that eccentricity pumping via interaction with a circumbinary disk is consistent with our inferred parameters. Finally, we report tentative evidence for pulsations that, if confirmed, would transform the star into an unprecedented laboratory for WD physics.

  12. Einstein@Home DISCOVERY OF A PALFA MILLISECOND PULSAR IN AN ECCENTRIC BINARY ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Knispel, B.; Allen, B. [Leibniz Universität, Hannover, D-30167 Hannover (Germany); Lyne, A. G.; Stappers, B. W. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Freire, P. C. C.; Lazarus, P. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Aulbert, C.; Bock, O.; Eggenstein, H.-B.; Fehrmann, H. [Max-Planck-Institut für Gravitationsphysik, Callinstr. 38, D-30167 Hannover (Germany); Bogdanov, S.; Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Brazier, A.; Chatterjee, S.; Cordes, J. M. [Department of Astronomy and Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States); Cardoso, F. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Crawford, F. [Department of Physics and Astronomy, Franklin and Marshall College, Lancaster, PA 17604-3003 (United States); Deneva, J. S. [National Research Council, resident at the Naval Research Laboratory, Washington, DC 20375 (United States); Ferdman, R. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Hessels, J. W. T., E-mail: benjamin.knispel@aei.mpg.de [ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); and others

    2015-06-10

    We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 M{sub ⊙} and is most likely a white dwarf (WD). Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities e < 0.001. However, four recently discovered binary MSPs have orbits with 0. 027 < e < 0.44; PSR J1950+2414 is the fifth such system to be discovered. The upper limits for its intrinsic spin period derivative and inferred surface magnetic field strength are comparable to those of the general MSP population. The large eccentricities are incompatible with the predictions of the standard recycling scenario: something unusual happened during their evolution. Proposed scenarios are (a) initial evolution of the pulsar in a triple system which became dynamically unstable, (b) origin in an exchange encounter in an environment with high stellar density, (c) rotationally delayed accretion-induced collapse of a super-Chandrasekhar WD, and (d) dynamical interaction of the binary with a circumbinary disk. We compare the properties of all five known eccentric MSPs with the predictions of these formation channels. Future measurements of the masses and proper motion might allow us to firmly exclude some of the proposed formation scenarios.

  13. Comparison of the Halving of Tablets Prepared with Eccentric and Rotary Tablet Presses

    OpenAIRE

    Sovány, T.; Kása Jr., P.; Pintye-Hódi, K.

    2009-01-01

    The aim of this study was to compare the densification of powder mixtures on eccentric and rotary tablet presses and to establish relationships with the halving properties of the resulting scored tablets. This is an important problem because the recent guidelines of EU require verification of the equal masses of tablet halves. The models of Walker, Heckel, and Kawakita were used to describe the powder densification on the two machines. The calculated parameters revealed that the shorter compr...

  14. The left ventricular eccentricity as a predictor of postoperative cardiac performance in valvular heart diseases.

    Science.gov (United States)

    Teramoto, S; Sano, S; Aokage, K; Shigenobu, M; Murakami, T; Kawakami, S; Nawa, S; Senoo, Y

    1982-04-01

    A clear correlation expressed by the following equation was observed between the preoperative left ventricular end-systolic eccentricity (epsilon s) and the percentage change of the left ventricular dimension (% delta D) in chronic valvular heart diseases: % delta D = 88.37 epsilon s - 48.16 (r = 0.66, p less than 0.001). Therefore, epsilon s may function as an index for predicting the postoperative cardiac performance independent of the affected valvular locations and the morphology of the lesions.

  15. On Line Current Monitoring and Application of a Residual Method for Eccentricity Fault Detection

    Directory of Open Access Journals (Sweden)

    METATLA, A.

    2011-02-01

    Full Text Available This work concerns the monitoring and diagnosis of faults in induction motors. We develop an approach based on residual analysis of stator currents to detect and diagnose faults eccentricity static, dynamic and mixed in three phase induction motor. To simulate the behavior of motor failure, a model is proposed based on the approach of magnetically coupled coils. The simulation results show the importance of the approach applied for the detection and diagnosis of fault in three phase induction motor.

  16. Sensitivity Analysis of the Dynamic Behavior of a Salient-Pole Synchronous Machine Considering the Static Rotor Eccentricity Effect

    Directory of Open Access Journals (Sweden)

    A. Román Messina

    2012-10-01

    Full Text Available This paper presents the sensitivity analysis of the behavior of a synchronous machine using the winding functiontheory considering the effect of static air-gap eccentricity. The winding function theory as a method to calculate theinductances of synchronous machines from the geometry and the actual arranging of the windings is presented. Then,detailed numerical simulations are carried out to examine the impact of eccentricity on the steady state regimes. Theimportant role of static eccentricity and its links with various symmetrical and asymmetrical operating conditions arediscussed as well as its influence on the machine parameters and performance are investigated. Experimental andanalytical parameter results are presented for a 60 Hz, six-pole laboratory synchronous machine connected to aninfinite bus under various static eccentricity conditions.

  17. Eccentric versus conventional exercise therapy in patients with rotator cuff tendinopathy: a randomized, single blinded, clinical trial

    NARCIS (Netherlands)

    Dejaco, B.; Habets, B.; Loon, C.J.M. van; Grinsven, S. van; Cingel, R.E. van

    2017-01-01

    PURPOSE: To investigate the effectiveness of isolated eccentric versus conventional exercise therapy in patients with rotator cuff tendinopathy. METHODS: Thirty-six patients with rotator cuff tendinopathy, diagnosed by an orthopaedic surgeon, were included and randomly allocated to an isolated

  18. The effect of passive stretching on delayed onset muscle soreness, and other detrimental effects following eccentric exercise

    DEFF Research Database (Denmark)

    Lund, Henrik; Vestergaard-Poulsen, P; Kanstrup, I.L.

    1998-01-01

    The aim of this study was to measure if passive stretching would influence delayed onset muscle soreness (DOMS), dynamic muscle strength, plasma creatine kinase concentration (CK) and the ratio of phosphocreatine to inorganic phosphate (PCr/P(i)) following eccentric exercise. Seven healthy...... untrained women, 28-46 years old, performed eccentric exercise with the right m. quadriceps in an isokinetic dynamometer (Biodex, angle velocity: 60 degrees.s-1) until exhaustion, in two different experiments, with an interval of 13-23 months. In both experiments the PCr/P(i) ratio, dynamic muscle strength...... and immediately after the eccentric exercise at day 0, and before measurements of the dependent variables daily for the following 7 d. The eccentric exercise alone led to significant decreases in PCr/P(i) ratio (P strength (P

  19. Muscle Damage following Maximal Eccentric Knee Extensions in Males and Females

    Science.gov (United States)

    2016-01-01

    Aim To investigate whether there is a sex difference in exercise induced muscle damage. Materials and Method Vastus Lateralis and patella tendon properties were measured in males and females using ultrasonography. During maximal voluntary eccentric knee extensions (12 reps x 6 sets), Vastus Lateralis fascicle lengthening and maximal voluntary eccentric knee extensions torque were recorded every 10° of knee joint angle (20–90°). Isometric torque, Creatine Kinase and muscle soreness were measured pre, post, 48, 96 and 168 hours post damage as markers of exercise induced muscle damage. Results Patella tendon stiffness and Vastus Lateralis fascicle lengthening were significantly higher in males compared to females (ptorque loss and muscle soreness post exercise induced muscle damage (p>0.05). Creatine Kinase levels post exercise induced muscle damage were higher in males compared to females (ptorque, relative to estimated quadriceps anatomical cross sectional area, was taken as a covariate (ptorque loss, there is no sex difference in exercise induced muscle damage. The higher Creatine Kinase in males could not be explained by differences in maximal voluntary eccentric knee extension torque, Vastus Lateralis fascicle lengthening and patella tendon stiffness. Further research is required to understand the significant sex differences in Creatine Kinase levels following exercise induced muscle damage. PMID:26986066

  20. CFD modelling of liquid-solid transport in the horizontal eccentric annuli

    Science.gov (United States)

    Sayindla, Sneha; Challabotla, Niranjan Reddy

    2017-11-01

    In oil and gas drilling operations, different types of drilling fluids are used to transport the solid cuttings in an annulus between drill pipe and well casing. The inner pipe is often eccentric and flow inside the annulus can be laminar or turbulent regime. In the present work, Eulerian-Eulerian granular multiphase CFD model is developed to systematically investigate the effect of the rheology of the drilling fluid type (Newtonian and non-Newtonian), drill pipe eccentricity and inner pipe rotation on the efficiency of cuttings transport. Both laminar and turbulent flow regimes were considered. Frictional pressure drop is computed and compared with the flow loop experimental results reported in the literature. The results confirm that the annular frictional pressure loss in a fully eccentric annulus are significantly lesser than the concentric annulus. Inner pipe rotation improve the efficiency of the cuttings transport in laminar flow regime. Cuttings transport velocity and concentration distribution were analysed to predict the different flow patterns such as stationary bed, moving bed, heterogeneous and homogeneous bed formation.

  1. Great expectations: top-down attention modulates the costs of clutter and eccentricity.

    Science.gov (United States)

    Steelman, Kelly S; McCarley, Jason S; Wickens, Christopher D

    2013-12-01

    An experiment and modeling effort examined interactions between bottom-up and top-down attentional control in visual alert detection. Participants performed a manual tracking task while monitoring peripheral display channels for alerts of varying salience, eccentricity, and spatial expectancy. Spatial expectancy modulated the influence of salience and eccentricity; alerts in low-probability locations engendered higher miss rates, longer detection times, and larger costs of visual clutter and eccentricity, indicating that top-down attentional control offset the costs of poor bottom-up stimulus quality. Data were compared to the predictions of a computational model of scanning and noticing that incorporates bottom-up and top-down sources of attentional control. The model accounted well for the overall pattern of miss rates and response times, predicting each of the observed main effects and interactions. Empirical results suggest that designers should expect the costs of poor bottom-up visibility to be greater for low expectancy signals, and that the placement of alerts within a display should be determined based on the combination of alert expectancy and response priority. Model fits suggest that the current model can serve as a useful tool for exploring a design space as a precursor to empirical data collection and for generating hypotheses for future experiments. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  2. EFFICACY OF CYRIAX PHYSIOTHERAPY VERSUS ECCENTRIC STRENGTHENING AND STRETCHING EXERCISES IN CHRONIC LATERAL EPICONDYLITIS PATIENTS

    Directory of Open Access Journals (Sweden)

    Madhusmita Koch

    2015-10-01

    Full Text Available Background: Lateral Epicondylitis is the most common lesion of the elbow, affecting the tendinous origin of the wrist extensors. Although conservative treatment of this condition has been the subject of numerous studies, there is no agreement as to the most effective management strategy. Therefore, this study was designed to compare the efficacy of Cyriax physiotherapy Versus Eccentric Strengthening and Stretching exercises in reducing the pain and improving the grip strength and functional status of the affected extremity in chronic lateral epicondylitis. Method: An experimental study design, 60 subjects meeting the inclusion criteria were selected for the study and were randomly assigned into two groups: Group A (N=30 received Cyriax Physiotherapy and Group B(N=30 received Eccentric strengthening and static stretching of Extensor Carpi Radialis Brevis. Low Level Laser Therapy was a common treatment for both the groups. After 4 weeks of treatment, assessment was performed using Visual Analogue Scale (VAS, Hand Held Dynamometer (HHD and Patient Rated Tennis Elbow Evaluation Questionnaire (PRTEE at 0 week and at the end of 4 weeks. Results: Data analysis revealed that there is no statistically significant difference between the groups in VAS, HHD and PRTEE scores i.e. average improvement post treatment in both the groups are equal, but within group comparisons showed significant improvements in both the groups. Conclusion: The efficacy of Cyriax Physiotherapy is equal to Eccentric Strengthening and Stretching Exercises in chronic lateral epicondylitis.

  3. Eccentric resistance training intensity may affect the severity of exercise induced muscle damage.

    Science.gov (United States)

    Hasenoehrl, Timothy; Wessner, Barbara; Tschan, Harald; Vidotto, Claudia; Crevenna, Richard; Csapo, Robert

    2017-09-01

    The aim of the present study was to assess the role of eccentric exercise intensity in the development of and recovery from delayed onset muscle soreness (DOMS). Using a cross-over study design, 15 healthy, male college students were tested on two occasions. The training stimulus consisted of an exhaustive series of eccentric muscle contractions of the elbow flexors at either 100% (high intensity) or 50% (low intensity) of the individual concentric one-repetition maximum. Blood samples were taken at baseline as well as 24, 48, 72 and 96 hours postexercise, and analyzed for creatine kinase, myoglobin, interleukin-6 and prostaglandin-2. Additionally, upper arm circumference (CIRC) and DOMS-related sensation of pain (PAIN) were measured. Following high intensity training, CIRC was significantly greater (P=0.007). Further, creatine kinase, myoglobin and interleukin-6 tended to be higher, although the main effect of the factor "intensity" just failed to reach significance (creatine kinase: P=0.056, myoglobin: P=0.064, interleukin-6: P=0.091). No differences were found for prostaglandin-2 (P=0.783) and PAIN (P=0.147). When performed at greater intensity, fatiguing eccentric resistance exercise of the elbow flexors leads to greater muscle swelling and, potentially, increases in serum markers reflecting lesions in the muscle's cellular membrane.

  4. Post-exercise muscle soreness after eccentric exercise: psychophysical effects and implications on mean arterial pressure.

    Science.gov (United States)

    Bajaj, P; Graven-Nielsen, T; Arendt-Nielsen, L

    2001-10-01

    The aim of the study was to examine the time course of changes in pressure pain threshold (PPT), visual analogue scale (VAS) pain and tenderness scores, McGill Pain Questionnaire (MPQ) descriptors, pain areas, skin temperature and mean arterial pressure (MAP) following intensive eccentric exercise. In 11 healthy male subjects, eccentric exercise of the first dorsal interosseous muscle (FDI) of the right hand with 114% maximum voluntary contraction weight (MVC) was used to induce post-exercise muscle soreness (PEMS) in the right hand, while the left hand served as a control. At 24 h to 48 h all the pain profiles indicated the presence of PEMS in the right hand when compared to before exercise (Pweb space of the hand did not change at any time. MAP was significantly reduced at 48 h. It is concluded that eccentric exercise of a small hand muscle is followed by PEMS and a reduced MAP after 48 h that may suggest a role of central mechanisms in the PEMS, thereby giving further insight into clinical aspects of muscle pain.

  5. Effects of microcurrent treatment on perceived pain and muscle strength following eccentric exercise.

    Science.gov (United States)

    Bonacci, J A; Higbie, E J

    1997-04-01

    The purpose of this study was to assess the effect of low-volt, microamperage stimulation (LVMAS) on perceived pain and muscle strength following an intense bout of eccentric exercise. An experimental pretest-posttest control group design was used for the study. The experiment was conducted in the Lower Extremity Research Laboratory at Georgia State University. Twelve females and six males (mean age 27 +/- 5 yr). Subjects, randomly assigned to experimental (EXP, n = 6), sham (SHAM, n = 6), and control (CON, n = 6) groups, were tested before, and at 24, 48, and 72 hours following, an intense bout of eccentric exercise. Three two-way (group x time) analyses of variance (ANOVAs) with repeated measures on the last factor were used to analyze the data. A significant time main effect was identified. Results indicated that perceived pain was not reduced in the EXP group as compared with the SHAM and CON groups. Muscle strength in the EXP group did not return to the initial baseline measure more rapidly than in the SHAM and CON groups. We conclude that the use of LVMAS alone is not effective in reducing pain and increasing muscle function following an exhaustive bout of eccentric exercise.

  6. Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

    Science.gov (United States)

    Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan EB; Kastner, Sabine; Hasson, Uri

    2015-01-01

    The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. DOI: http://dx.doi.org/10.7554/eLife.03952.001 PMID:25695154

  7. Eccentric loading and range of knee joint motion effects on performance enhancement in vertical jumping.

    Science.gov (United States)

    Moran, Kieran A; Wallace, Eric S

    2007-12-01

    The aim of the study was to determine the effects of variations in eccentric loading and knee joint range of motion on performance enhancement associated with the stretch-shortening cycle in vertical jumping. Seventeen male elite volleyball players performed three variations of the vertical jump which served as the research model: the squat jump (SJ), countermovement jump (CMJ) and drop jump from a height of 30 cm (DJ30). Knee joint angle (70 degrees and 90 degrees of flexion) at the commencement of the propulsive phase for each jump type was experimentally controlled, with the trunk kept as erect as possible. Force and motion data were recorded for each performance and used to compute a range of kinematic and kinetic variables, including hip, knee and ankle angles, angular velocities, work done, net joint moments and a number of temporal variables. The average of 12 trials for each participant was used in a series of repeated measures ANOVA's (jump xk nee, alpha=.05). From both knee joint angles, an increase in eccentric loading resulted in a significant increase in jump height (DJ30>CMJ>SJ; pjumping is dependent upon the interaction of the magnitude of eccentric loading and the range of motion used.

  8. Study on the optical properties of the off-axis parabolic collimator with eccentric pupil

    Science.gov (United States)

    Li, Gang; Gao, Xin; Duan, Jing; Zhang, Henjin

    2017-02-01

    The off-axis parabolic collimator with eccentric pupil has the advantages of wide spectrum, simple structure, easy assembly and adjustment, high performance price ratio. So, it is widely used for parameters testing and image quality calibration of ground-based and space-based cameras. In addition to the Strehl ratio, resolution, wavefront aberration, modulation transfer function, the general evaluation criteria on the imaging quality of the optical system, the beam parallelism characterize the collimator angle resolving capability and collimation condition of the collimator with the target board, can be measured easily ,quickly and operation process is simple, but the study mainly focus on how to measure it so far. In order to solve Quantitative calculation of this problem, firstly, the discussion of aberration condition of the off- axis parabolic is carried out based on the primary aberration theory. Secondly, analysis on the influencing factor on collimator optical properties is given, including the geometrical aberrations of spherical aberration, coma, astigmatism , the relation between the position of the eccentric pupil and the aberration and optical element surface wavefront aberration, after that, according to the basis of diffraction and wavefront aberration theory, the paper deduced calculation method of the beam parallelism, at last, an example of a 400mm diameter off-axis parabolic collimator with eccentric pupil is given to calculate, the practical results shows that calculation data is well in accordance with actual measurement data and results can meet the demand and has a guiding significance to the actual project manufacture and the theory analysis.

  9. Creep and cracking of concrete hinges: insight from centric and eccentric compression experiments.

    Science.gov (United States)

    Schlappal, Thomas; Schweigler, Michael; Gmainer, Susanne; Peyerl, Martin; Pichler, Bernhard

    2017-01-01

    Existing design guidelines for concrete hinges consider bending-induced tensile cracking, but the structural behavior is oversimplified to be time-independent. This is the motivation to study creep and bending-induced tensile cracking of initially monolithic concrete hinges systematically. Material tests on plain concrete specimens and structural tests on marginally reinforced concrete hinges are performed. The experiments characterize material and structural creep under centric compression as well as bending-induced tensile cracking and the interaction between creep and cracking of concrete hinges. As for the latter two aims, three nominally identical concrete hinges are subjected to short-term and to longer-term eccentric compression tests. Obtained material and structural creep functions referring to centric compression are found to be very similar. The structural creep activity under eccentric compression is significantly larger because of the interaction between creep and cracking, i.e. bending-induced cracks progressively open and propagate under sustained eccentric loading. As for concrete hinges in frame-like integral bridge construction, it is concluded (i) that realistic simulation of variable loads requires consideration of the here-studied time-dependent behavior and (ii) that permanent compressive normal forces shall be limited by 45% of the ultimate load carrying capacity, in order to avoid damage of concrete hinges under sustained loading.

  10. Eccentric exercise prior to hindlimb unloading attenuated reloading muscle damage in rats.

    Science.gov (United States)

    Prisby, Rhonda D; Nelson, Arnold G; Latsch, Elizabeth

    2004-11-01

    Antigravity muscles that are reloaded subsequent to hindlimb unloading (HU) are prone to injury. Similarities exist between muscle damage elicited from HU and subsequent reloading and damage induced by eccentric exercise (EE). Conditioning bouts of EE reduce muscle damage following a repeat bout of EE. Since damage to reloaded skeletal muscle is comparable to damage observed after EE, the mechanisms of damage are presumably similar. Therefore, EE prior to HU may attenuate reloading muscle damage. This study evaluated the effects of prior EE on rat soleus muscles (SOL) subsequent to 7 d of HU and 16-19 h of reloading. Sprague Dawley rats were randomly assigned to the following groups: eccentric exercise + hindlimb unloading + reloading (EEHUR; n = 9); hindlimb unloading + reloading (HUR; n = 10); eccentric exercise (EE; n = 12), or control (CON; n = 12). The exercise protocol was performed 5 d x wk(-1) for 2 wks followed by HU and reloading. Fiber areas were lower in both suspended groups vs. the EE and CON groups. There was no difference in percent interstitial area among groups. However, percent myofibrillar damage was higher in the HUR group vs. all other groups. Further, glucose-6-phospate dehydrogenase activity, an indicator of muscle damage, was higher in the HUR group compared with the EE and CON groups. These results provide some evidence that prior EE reduced muscle damage subsequent to HU and reloading. Therefore, EE may prove effective in minimizing recovery time in individuals suffering from muscle damage following periods of bed rest and spaceflight.

  11. A High-Eccentricity Low-Mass Companion to HD 89744.

    Science.gov (United States)

    Korzennik; Brown; Fischer; Nisenson; Noyes

    2000-04-20

    HD 89744 is an F7 V star with a mass of 1.4 M middle dot in circle, an effective temperature of 6166 K, an age of 2.0 Gyr, and metallicity &sqbl0;Fe&solm0;H&sqbr0;=0.18. The radial velocity of the star has been monitored with the Advanced Fiber-Optic Echelle spectrograph at the Whipple Observatory since 1996, and evidence has been found for a low-mass companion. The data were complemented by additional data from the Hamilton spectrograph at Lick Observatory during the companion's periastron passage in the fall of 1999. As a result, we have determined the star's orbital wobble to have a period P=256 days, an orbital amplitude K=257 m s-1, and an eccentricity e=0.7. From the stellar mass, we infer that the companion has a minimum mass m2sini=7.2 MJ in an orbit with a semimajor axis a2=0.88 AU. The eccentricity of the orbit, among the highest known for extrasolar planets, continues the trend that extrasolar planets with semimajor axes greater than about 0.15 AU tend to have much higher eccentricities than are found in our solar system. The high metallicity of the parent star reinforces the trend that parent stars of extrasolar planets tend to have high metallicity.

  12. [Eccentric strength training for the rotator cuff tendinopathies with subacromial impingement. Current evidence].

    Science.gov (United States)

    Macías-Hernández, Salvador Israel; Pérez-Ramírez, Luis Enrique

    2015-01-01

    Rotator cuff tears are the leading cause of pain and functional disability of the shoulder. Conservative treatment is an essential part of their management. Despite the limited evidence, rehabilitation is the mainstay of the treatment for rotator cuff tears associated to impingement syndrome. There are current reports on the utility of strengthening with resistance, particularly by eccentric exercise. This report aims to present an overview of the efficacy of eccentric exercises in tendinopathies and current evidence of its benefit in rotator cuff tears. We describe the information available in tendinopathy and analyzed four studies published on eccentric strengthening for rotator cuff tears. There is theoretical evidence about its usefulness in this pathology, but only a controlled clinical trial has been published with data on improvement in strength but not in pain or functionality. More studies are needed with better methodological designs in order to generate evidence of their utility and recommendation. Copyright © 2015. Published by Masson Doyma México S.A.

  13. Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Huicheng; Wong, Teck Neng, E-mail: mtnwong@ntu.edu.sg; Marcos [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Che, Zhizhao [State Key Laboratory of Engines, Tianjin University, Tianjin 300072 (China)

    2016-06-15

    Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

  14. 3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

    Directory of Open Access Journals (Sweden)

    FAROUK TAHROUR

    2015-11-01

    Full Text Available The use of 3-D computational fluid dynamics (CFD is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, this study analyzes the effects of fin spacing and fin tube diameter on heat transfer and flow characteristics for a range of Reynolds numbers, 4500≤Re≤22500. A satisfactory qualitative and quantitative agreement was obtained between the numerical predictions and the results published in the literature. For small fin spacings, the eccentric annular finned tube is more efficient than the concentric one. Among the cases examined, the average heat transfer coefficient of the eccentric annular-finned tube, for a tube shift St =12 mm and a Reynolds number Re = 9923, was 7.61% greater than that of the concentric one. This gain is associated with a 43.09% reduction in pressure drop.

  15. Einstein@Home Discovery of a PALFA Millisecond Pulsar in an Eccentric Binary Orbit

    Science.gov (United States)

    Knispel, B.; Lyne, A. G.; Stappers, B. W.; Freire, P. C. C.; Lazarus, P.; Allen, B.; Aulbert, C.; Bock, O.; Bogdanov, S.; Brazier, A.; Camilo, F.; Cardoso, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J. S.; Eggenstein, H.-B.; Fehrmann, H.; Ferdman, R.; Hessels, J. W. T.; Jenet, F. A.; Karako-Argaman, C.; Kaspi, V. M.; van Leeuwen, J.; Lorimer, D. R.; Lynch, R.; Machenschalk, B.; Madsen, E.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Scholz, P.; Siemens, X.; Spitler, L. G.; Stairs, I. H.; Stovall, K.; Swiggum, J. K.; Venkataraman, A.; Wharton, R. S.; Zhu, W. W.

    2015-06-01

    We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 M⊙ and is most likely a white dwarf (WD). Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities e recycling scenario: something unusual happened during their evolution. Proposed scenarios are (a) initial evolution of the pulsar in a triple system which became dynamically unstable, (b) origin in an exchange encounter in an environment with high stellar density, (c) rotationally delayed accretion-induced collapse of a super-Chandrasekhar WD, and (d) dynamical interaction of the binary with a circumbinary disk. We compare the properties of all five known eccentric MSPs with the predictions of these formation channels. Future measurements of the masses and proper motion might allow us to firmly exclude some of the proposed formation scenarios.

  16. The rectilinear three-body problem as a basis for studying highly eccentric systems

    Science.gov (United States)

    Voyatzis, G.; Tsiganis, K.; Gaitanas, M.

    2018-01-01

    The rectilinear elliptic restricted three-body problem (TBP) is the limiting case of the elliptic restricted TBP when the motion of the primaries is described by a Keplerian ellipse with eccentricity e'=1, but the collision of the primaries is assumed to be a non-singular point. The rectilinear model has been proposed as a starting model for studying the dynamics of motion around highly eccentric binary systems. Broucke (AIAA J 7:1003-1009, 1969) explored the rectilinear problem and obtained isolated periodic orbits for mass parameter μ =0.5 (equal masses of the primaries). We found that all orbits obtained by Broucke are linearly unstable. We extend Broucke's computations by using a finer search for symmetric periodic orbits and computing their linear stability. We found a large number of periodic orbits, but only eight of them were found to be linearly stable and are associated with particular mean motion resonances. These stable orbits are used as generating orbits for continuation with respect to μ and e'systems of very highly eccentric orbits can be found in stable resonant configurations. As an application we present a stability study for the planetary system HD7449.

  17. Influence of borehole-eccentred tools on wireline and logging-while-drilling sonic logging measurements

    KAUST Repository

    Pardo, David

    2013-02-13

    We describe a numerical study to quantify the influence of tool-eccentricity on wireline (WL) and logging-while-drilling (LWD) sonic logging measurements. Simulations are performed with a height-polynomial-adaptive (hp) Fourier finite-element method that delivers highly accurate solutions of linear visco-elasto-acoustic problems in the frequency domain. The analysis focuses on WL instruments equipped with monopole or dipole sources and LWD instruments with monopole excitation. Analysis of the main propagation modes obtained from frequency dispersion curves indicates that the additional high-order modes arising as a result of borehole-eccentricity interfere with the main modes (i.e., Stoneley, pseudo-Rayleigh and flexural). This often modifies (decreases) the estimation of shear and compressional formation velocities, which should be corrected (increased) to account for borehole-eccentricity effects. Undesired interferences between different modes can occur at different frequencies depending upon the properties of the formation and fluid annulus size, which may difficult the estimation of the formation velocities. © 2013 European Association of Geoscientists & Engineers.

  18. Benefits of dietary phytochemical supplementation on eccentric exercise-induced muscle damage: Is including antioxidants enough?

    Science.gov (United States)

    Pereira Panza, Vilma Simões; Diefenthaeler, Fernando; da Silva, Edson Luiz

    2015-09-01

    The purpose of this review was to critically discuss studies that investigated the effects of supplementation with dietary antioxidant phytochemicals on recovery from eccentric exercise-induced muscle damage. The performance of physical activities that involve unaccustomed eccentric muscle actions-such as lowering a weight or downhill walking-can result in muscle damage, oxidative stress, and inflammation. These events may be accompanied by muscle weakness and delayed-onset muscle soreness. According to the current evidences, supplementation with dietary antioxidant phytochemicals appears to have the potential to attenuate symptoms associated with eccentric exercise-induced muscle damage. However, there are inconsistencies regarding the relationship between muscle damage and blood markers of oxidative stress and inflammation. Furthermore, the effectiveness of strategies appear to depend on a number of aspects inherent to phytochemical compounds as well as its food matrix. Methodological issues also may interfere with the proper interpretation of supplementation effects. Thus, the study may contribute to updating professionals involved in sport nutrition as well as highlighting the interest of scientists in new perspectives that can widen dietary strategies applied to training. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Vitamin D2 supplementation amplifies eccentric exercise-induced muscle damage in NASCAR pit crew athletes.

    Science.gov (United States)

    Nieman, David C; Gillitt, Nicholas D; Shanely, R Andrew; Dew, Dustin; Meaney, Mary Pat; Luo, Beibei

    2013-12-20

    This study determined if 6-weeks vitamin D2 supplementation (vitD2, 3800 IU/day) had an influence on muscle function, eccentric exercise-induced muscle damage (EIMD), and delayed onset of muscle soreness (DOMS) in National Association for Stock Car Auto Racing (NASCAR) NASCAR pit crew athletes. Subjects were randomized to vitD2 (n=13) and placebo (n=15), and ingested supplements (double-blind) for six weeks. Blood samples were collected and muscle function tests conducted pre- and post-study (leg-back and hand grip dynamometer strength tests, body weight bench press to exhaustion, vertical jump, 30-s Wingate test). Post-study, subjects engaged in 90 min eccentric-based exercise, with blood samples and DOMS ratings obtained immediately after and 1- and 2-days post-exercise. Six weeks vitD2 increased serum 25(OH)D2 456% and decreased 25(OH)D3 21% versus placebo (pNASCAR pit crew athletes following eccentric exercise.

  20. Acoustic anisotropic wavefields through perturbation theory

    KAUST Repository

    Alkhalifah, Tariq Ali

    2013-09-01

    Solving the anisotropic acoustic wave equation numerically using finite-difference methods introduces many problems and media restriction requirements, and it rarely contributes to the ability to resolve the anisotropy parameters. Among these restrictions are the inability to handle media with η<0 and the presence of shear-wave artifacts in the solution. Both limitations do not exist in the solution of the elliptical anisotropic acoustic wave equation. Using perturbation theory in developing the solution of the anisotropic acoustic wave equation allows direct access to the desired limitation-free solutions, that is, solutions perturbed from the elliptical anisotropic background medium. It also provides a platform for parameter estimation because of the ability to isolate the wavefield dependency on the perturbed anisotropy parameters. As a result, I derive partial differential equations that relate changes in the wavefield to perturbations in the anisotropy parameters. The solutions of the perturbation equations represented the coefficients of a Taylor-series-type expansion of the wavefield as a function of the perturbed parameter, which is in this case η or the tilt of the symmetry axis. The expansion with respect to the symmetry axis allows use of an acoustic transversely isotropic media with a vertical symmetry axis (VTI) kernel to estimate the background wavefield and the corresponding perturbation coefficients. The VTI extrapolation kernel is about one-fourth the cost of the transversely isotropic model with a tilt in the symmetry axis kernel. Thus, for a small symmetry axis tilt, the cost of migration using a first-order expansion can be reduced. The effectiveness of the approach was demonstrated on the Marmousi model.

  1. Effects of resistance training using known vs unknown loads on eccentric-phase adaptations and concentric velocity.

    Science.gov (United States)

    Hernández-Davó, J L; Sabido, R; Behm, D G; Blazevich, A J

    2018-02-01

    The aims of this study were to compare both eccentric- and concentric-phase adaptations in highly trained handball players to 4 weeks of twice-weekly rebound bench press throw training with varying loads (30%, 50% and 70% of one-repetition maximum [1-RM]) using either known (KL) or unknown (UL) loads and to examine the relationship between changes in eccentric- and concentric-phase performance. Twenty-eight junior team handball players were divided into two experimental groups (KL or UL) and a control group. KL subjects were told the load prior each repetition, while UL were blinded. For each repetition, the load was dropped and then a rebound bench press at maximum velocity was immediately performed. Both concentric and eccentric velocity as well as eccentric kinetic energy and musculo-articular stiffness prior to the eccentric-concentric transition were measured. Results showed similar increases in both eccentric velocity and kinetic energy under the 30% 1-RM but greater improvements under 50% and 70% 1-RM loads for UL than KL. UL increased stiffness under all loads (with greater magnitude of changes). KL improved concentric velocity only under the 30% 1-RM load while UL also improved under 50% and 70% 1-RM loads. Improvements in concentric movement velocity were moderately explained by changes in eccentric velocity (R 2 =.23-.62). Thus, UL led to greater improvements in concentric velocity, and the improvement is potentially explained by increases in the speed (as well as stiffness and kinetic energy) of the eccentric phase. Unknown load training appears to have significant practical use for the improvement of multijoint stretch-shortening cycle movements. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Note: how to design Gaussian filter with eccentricity and probe offset taken into account for roundness measurement of small radius.

    Science.gov (United States)

    Wang, Lei; Liu, Pei; Tan, Jiubin; Wang, Long; Ding, Xiaohui

    2012-05-01

    A Gaussian filter is designed using circular convolution with eccentricity and probe offset taken into account for roundness measurement. It is found through analyses and experiments that the newly designed filter can perform as well as a fast Fourier Gaussian filter for high precision calibration in laboratory, and it can be better used for roundness measurement of small radius with high eccentricity and probe offset as well.

  3. The effect of orbital damping during planet migration on the Inclination and Eccentricity Distributions of Neptune Trojans

    OpenAIRE

    Chen, Yuan-yuan; Ma, Yuehua; Zheng, Jiaqing

    2016-01-01

    We explore planetary migration scenarios for formation of high inclination Neptune Trojans (NTs) and how they are affected by the planetary migration of Neptune and Uranus. If Neptune and Uranus's eccentricity and inclination were damped during planetary migration, then their eccentricities and inclinations were higher prior and during migration than their current values. Using test particle integrations we study the stability of primordial NTs, objects that were initially Trojans with Neptun...

  4. Isokinetic eccentric exercise can induce skeletal muscle injury within the physiologic excursion of muscle-tendon unit: a rabbit model

    Directory of Open Access Journals (Sweden)

    Chen Pei-Yu

    2007-08-01

    Full Text Available Abstract Background and Purpose Intensive eccentric exercise can cause muscle damage. We simulated an animal model of isokinetic eccentric exercise by repetitively stretching stimulated triceps surae muscle-tendon units to determine if such exercise affects the mechanical properties of the unit within its physiologic excursion. Methods Biomechanical parameters of the muscle-tendon unit were monitored during isokinetic eccentric loading in 12 rabbits. In each animal, one limb (control group was stretched until failure. The other limb (study group was first subjected to isokinetic and eccentric cyclic loading at the rate of 10.0 cm/min to 112% (group I or 120% (group II of its initial length for 1 hour and then stretched to failure. Load-deformation curves and biomechanical parameters were compared between the study and control groups. Results When the muscle-tendon unit received eccentric cyclic loading to 112%, changes in all biomechanical parameters – except for the slope of the load-deformation curve – were not significant. In contrast, most parameters, including the slope of the load-deformation curve, peak load, deformation at peak load, total energy absorption, and energy absorption before peak load, significantly decreased after isokinetic eccentric cyclic loading to 120%. Conclusion We found a threshold for eccentrically induced injury of the rabbit triceps surae muscle at between 12% and 20% strain, which is within the physiologic excursion of the muscle-tendon units. Our study provided evidence that eccentric exercise may induce changes in the biomechanical properties of skeletal muscles, even within the physiologic range of the excursion of the muscle-tendon unit.

  5. Formation of Close-in Super-Earths by Giant Impacts: Effects of Initial Eccentricities and Inclinations of Protoplanets

    Science.gov (United States)

    Matsumoto, Yuji; Kokubo, Eiichiro

    2017-07-01

    Recent observations have revealed the eccentricity and inclination distributions of close-in super-Earths. These distributions have the potential to constrain their formation processes. In the in situ formation scenario, the eccentricities and inclinations of planets are determined by gravitational scattering and collisions between protoplanets on the giant impact stage. We investigate the effect of the initial eccentricities and inclinations of protoplanets on the formation of close-in super-Earths. We perform N-body simulations of protoplanets in gas-free disks, changing the initial eccentricities and inclinations systematically. We find that while the eccentricities of protoplanets are well relaxed through their evolution, the inclinations are not. When the initial inclinations are small, they are not generally pumped up since scattering is less effective and collisions occur immediately after orbital crossing. On the other hand, when the initial inclinations are large, they tend to be kept large since collisional damping is less effective. Not only the resultant inclinations of planets, but also their number, eccentricities, angular momentum deficit, and orbital separations are affected by the initial inclinations of protoplanets.

  6. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    Directory of Open Access Journals (Sweden)

    Askar P.V

    2015-12-01

    Full Text Available Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dynamic range of motion (DROM exercise in improving hamstring flexibility and the second objective is find which technique is more effective in improving hamstring flexibility when compared with a control group. Study design is Experimental pre-test post-test design. Methods: 88 male subjects with limited hamstring flexibility were recruited for this study were assigned to four group. Group1 received eccentric training, group2 received dynamic range of motion exercise, group3 received static stretching and group4 was served as control group. Hamstring length was measured pre intervention and post intervention using a self-monitored active knee extension test. Results: Eccentric training, static stretching and dynamic range of motion exercise showed a significant increase in hamstring length between pre and post intervention. Following a between group analysis done by independent t test revealed a significant difference between group1 group2 and group3 Conclusion: It is concluded that eccentric training, dynamic range of motion (DROM exercise and static stretching groups improved hamstring flexibility.

  7. Response of Coagulation Indices to Two Types of Exercise of Eccentric and Isometric in Male Bodybuilding Athletes

    Directory of Open Access Journals (Sweden)

    Maryam Azimpour

    2016-05-01

    Full Text Available Abstract Background and Objectives: Although activation of blood coagulation system in response to physical activity has been identified to some extent, but the contribution of eccentric activity in comparison with isometric activity as resistance exercise, is not clear yet. Therefore, this research was carried out with the purpose of investigating the effect of one session of eccentric and isometric resistance exercise on some coagulation factors in male bodybuilders. Methods: In this semi-experimental study, 28 volunteers were randomly selected from male bodybuilders and divided into two experimental groups and one control group. One of the experimental groups performed eccentric exercise [controlled return (extension of the elbow flexion movement involving an eccentric contraction] and another group performed isometric exercises (holding barbell while flexing elbows at 45 degrees. In order to assess coagulation indices, blood sampling was performed 15 minutes before and immediately after the exercise. Results: Thromboplastin and prothrombin times did not significantly change immediately after the exercise, but the number of platelets significantly increased in both isometric and eccentric types of exercise immediately after the exercise. Conclusion: The results of isometric and eccentric acute resistance exercise showed that the exercise had no negative impact on blood coagulation factors, and increased coagulation system activity reflects the increased number of platelets. The difference between the results of researches carried out in this direction can be resulted from the difference between the exercise protocols, methods and measurement time, and level of preparedness of the participants in the research.

  8. Cosmological perturbations on the Phantom brane

    CERN Document Server

    Bag, Satadru; Shtanov, Yuri; Sahni, Varun

    2016-01-01

    We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, $w_{\\rm eff} < -1$, but no big-rip future singularity. In addition to matter and radiation, the braneworld possesses a new effective degree of freedom - the 'Weyl fluid' or 'dark radiation'. Setting initial conditions on super-Hubble spatial scales at the epoch of radiation domination, we evolve perturbations of radiation, pressureless matter and the Weyl fluid until the present epoch. We observe a gradual decrease in the amplitude of the Weyl-fluid perturbations after Hubble-radius crossing, which results in a negligible effect of the Weyl fluid on the evolution of matter perturbations on spatial scales relevant for structure formation. Consequently, the quasi-static approximation of Koyama and Maartens provides a good fit to the exact results during the matter-dominated epoch. We find that the late-time growth of density perturbations on...

  9. Unique Fock quantization of scalar cosmological perturbations

    CERN Document Server

    Fernández-Méndez, Mikel; Olmedo, Javier; Velhinho, José M

    2012-01-01

    We investigate the ambiguities in the Fock quantization of the scalar perturbations of a Friedmann-Lema\\^{i}tre-Robertson-Walker model with a massive scalar field as matter content. We consider the case of compact spatial sections (thus avoiding infrared divergences), with the topology of a three-sphere. After expanding the perturbations in series of eigenfunctions of the Laplace-Beltrami operator, the Hamiltonian of the system is written up to quadratic order in them. We fix the gauge of the local degrees of freedom in two different ways, reaching in both cases the same qualitative results. A canonical transformation, which includes the scaling of the matter field perturbations by the scale factor of the geometry, is performed in order to arrive at a convenient formulation of the system. We then study the quantization of these perturbations in the classical background determined by the homogeneous variables. Based on previous work, we introduce a Fock representation for the perturbations in which: (a) the co...

  10. Testing perturbative results with non-perturbative methods for the Hierarchical model

    OpenAIRE

    Meurice, Y.; Oktay, M. B.

    2000-01-01

    We present non-perturbative methods to calculate accurately the renormalized quantities for Dyson's Hierarchical Model. We apply this method and calculate the critical exponent gamma with 12 and 4 significant digits in the high and low temperature phases, respectively. We report accurate values for universal ratios of amplitudes and preliminary results concerning the comparison with perturbative results.

  11. Perturbative Saturation and the Soft Pomeron

    CERN Document Server

    Kovner, A; Kovner, Alex; Wiedemann, Urs Achim

    2002-01-01

    We show that perturbation theory provides two distinct mechanisms for the power like growth of hadronic cross sections at high energy. One, the leading BFKL effect is due to the growth of the parton density, and is characterized by the leading BFKL exponent. The other mechanism is due to the infrared diffusion, or the long range nature of the Coulomb field of perturbatively massless gluons. When perturbative saturation effects are taken into account, the first mechanism is rendered ineffective but the second one persists. We suggest that these two distinct mechanisms are responsible for the appearance of two pomerons. The density growth effects are responsible for the hard pomeron and manifest themselves in small systems (e.g. gamma^* or small size fluctuations in the proton wave function) where saturation effects are not important. The soft pomeron is the manifestation of the exponential growth of the black saturated regions which appear in typical hadronic systems. We point out that the nonlinear generaliza...

  12. Covariant perturbations in the gonihedric string model

    Science.gov (United States)

    Rojas, Efraín

    2017-11-01

    We provide a covariant framework to study classically the stability of small perturbations on the so-called gonihedric string model by making precise use of variational techniques. The local action depends on the square root of the quadratic mean extrinsic curvature of the worldsheet swept out by the string, and is reparametrization invariant. A general expression for the worldsheet perturbations, guided by Jacobi equations without any early gauge fixing, is obtained. This is manifested through a set of highly coupled nonlinear differential partial equations where the perturbations are described by scalar fields, Φi, living in the worldsheet. This model contains, as a special limit, to the linear model in the mean extrinsic curvature. In such a case the Jacobi equations specialize to a single wave-like equation for Φ.

  13. Gravitino perturbations in Schwarzschild black holes

    CERN Document Server

    Piedra, Owen Pavel Fernández

    2010-01-01

    We consider the time evolution of massless gravitino perturbations in Schwarzschild black holes, and show that as in the case of fields of other values of spin, the evolution comes in three stages, after an initial outburst as a first stage, we observe the damped oscillations characteristic of the quasinormal ringing stage, followed by long time tails. Using the sixth order WKB method and Prony fitting of time domain data we determine the quasinormal frequencies. There is a good correspondence between the results obtained by the above two methods, and we obtain a considerable improvement with respect to the previously obtained third order WKB results. We also show that the response of a black hole depends crucially on the spin class of the perturbing field: the quality factor becomes a decreasing function of the spin for boson perturbations , whereas the opposite situation appears for fermion ones.

  14. One dimensional systems with singular perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, J J [Departamento de Informatica, E.U. de Informatica, Universidad de Valladolid, 40005 Segovia (Spain); Gadella, M; Nieto, L M [Departamento de FTAO, University of Valladolid, 47071 Valladolid (Spain); Glasser, L M [Department of Physics, Clarkson University, Potsdam, NY 13699-5820 (United States); Lara, L P, E-mail: jjalvarez@infor.uva.es, E-mail: manuelgadella1@gmail.com, E-mail: laryg@clarkson.edu, E-mail: lplara@fceia.unr.edu.ar, E-mail: luismi@metodos.fam.cie.uva.es [Departamento de Sistemas, FRRO, Zevallos 1345, Rosario (Argentina)

    2011-03-01

    This paper discusses some one dimensional quantum models with singular perturbations. Eventually, a mass discontinuity is added at the points that support the singular perturbations. The simplest model includes an attractive singular potential with a mass jump both located at the origin. We study the form of the only bound state. Another model exhibits a hard core at the origin plus one or more repulsive deltas with mass jumps at the points supporting these deltas. We study the location and the multiplicity of these resonances for the case of one or two deltas and settle the basis for a generalization. Finally, we consider the harmonic oscillator and the infinite square well plus a singular potential at the origin. We see how the energy of bound states is affected by the singular perturbation.

  15. Chiral Perturbation Theory With Lattice Regularization

    CERN Document Server

    Ouimet, P P A

    2005-01-01

    In this work, alternative methods to regularize chiral perturbation theory are discussed. First, Long Distance Regularization will be considered in the presence of the decuplet of the lightest spin 32 baryons for several different observables. This serves motivation and introduction to the use of the lattice regulator for chiral perturbation theory. The mesonic, baryonic and anomalous sectors of chiral perturbation theory will be formulated on a lattice of space time points. The consistency of the lattice as a regulator will be discussed in the context of the meson and baryon masses. Order a effects will also be discussed for the baryon masses, sigma terms and magnetic moments. The work will close with an attempt to derive an effective Wess-Zumino-Witten Lagrangian for Wilson fermions at non-zero a. Following this discussion, there will be a proposal for a phenomenologically useful WZW Lagrangian at non-zero a.

  16. Death to perturbative QCD in exclusive processes?

    Energy Technology Data Exchange (ETDEWEB)

    Eckardt, R.; Hansper, J.; Gari, M.F. [Institut fuer Theoretische Physik, Bochum (Germany)

    1994-04-01

    The authors discuss the question of whether perturbative QCD is applicable in calculations of exclusive processes at available momentum transfers. They show that the currently used method of determining hadronic quark distribution amplitudes from QCD sum rules yields wave functions which are completely undetermined because the polynomial expansion diverges. Because of the indeterminacy of the wave functions no statement can be made at present as to whether perturbative QCD is valid. The authors emphasize the necessity of a rigorous discussion of the subject and the importance of experimental data in the range of interest.

  17. Unphysical states in staggered chiral perturbation theory

    CERN Document Server

    Aubin, Christopher; Davila, George

    2015-01-01

    We study the extended phase diagram for staggered quarks using chiral perturbation theory. Recent beyond-the-standard-model simulations have shown that broken phases occur for coarse enough lattice spacing, so long as the number of quark flavors in the simulation is large enough (greater than eight). One of the phases seen in these simulations can be studied in depth using chiral perturbation theory. We also show that there are only three broken phases for staggered quarks that can arise, at least for lattice spacings in the regime a^2<< Lambda^2_{QCD}.

  18. Perturbations of C*-algebraic Invariants

    DEFF Research Database (Denmark)

    Christensen, Erik; Sinclair, Allan M.; Smith, Roger R.

    2010-01-01

    The setting of the article is the so-called theory of perturbations of algebras of operators. It is shown that several of the properties a C*-algebra may have are preseved under pertubations. The main result states that Pisier's concept finite length is a stasble property.......The setting of the article is the so-called theory of perturbations of algebras of operators. It is shown that several of the properties a C*-algebra may have are preseved under pertubations. The main result states that Pisier's concept finite length is a stasble property....

  19. Galilean invariant resummation schemes of cosmological perturbations

    Science.gov (United States)

    Peloso, Marco; Pietroni, Massimo

    2017-01-01

    Many of the methods proposed so far to go beyond Standard Perturbation Theory break invariance under time-dependent boosts (denoted here as extended Galilean Invariance, or GI). This gives rise to spurious large scale effects which spoil the small scale predictions of these approximation schemes. By using consistency relations we derive fully non-perturbative constraints that GI imposes on correlation functions. We then introduce a method to quantify the amount of GI breaking of a given scheme, and to correct it by properly tailored counterterms. Finally, we formulate resummation schemes which are manifestly GI, discuss their general features, and implement them in the so called Time-Flow, or TRG, equations.

  20. Conservative perturbation theory for nonconservative systems.

    Science.gov (United States)

    Shah, Tirth; Chattopadhyay, Rohitashwa; Vaidya, Kedar; Chakraborty, Sagar

    2015-12-01

    In this paper, we show how to use canonical perturbation theory for dissipative dynamical systems capable of showing limit-cycle oscillations. Thus, our work surmounts the hitherto perceived barrier for canonical perturbation theory that it can be applied only to a class of conservative systems, viz., Hamiltonian systems. In the process, we also find Hamiltonian structure for an important subset of Liénard system-a paradigmatic system for modeling isolated and asymptotic oscillatory state. We discuss the possibility of extending our method to encompass an even wider range of nonconservative systems.

  1. A generalized perturbation program for CANDU reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Heon; Kim, Jong Kyung [Hanyang University, Seoul (Korea, Republic of); Choi, Hang Bok; Roh, Gyu Hong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Yang, Won Sik [Chosun University, Kwangju (Korea, Republic of)

    1998-12-31

    A generalized perturbation program has been developed for the purpose of estimating zonal power variation of a CANDU reactor upon refueling operation. The forward and adjoint calculation modules of RFSP code were used to construct the generalized perturbation program. The numerical algorithm for the generalized adjoint flux calculation was verified by comparing the zone power estimates upon refueling with those of forward calculation. It was, however, noticed that the truncation error from the iteration process of the generalized adjoint flux is not negligible. 2 refs., 1 figs., 1 tab. (Author)

  2. Perturbative and nonperturbative renormalization in lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [University of Edinburgh (United Kingdom). School of Physics and Astronomy; Perlt, H. [Leipzig Univ. (DE). Institut fuer Theoretische Physik] (and others)

    2010-03-15

    We investigate the perturbative and nonperturbative renormalization of composite operators in lattice QCD restricting ourselves to operators that are bilinear in the quark fields (quark-antiquark operators). These include operators which are relevant to the calculation of moments of hadronic structure functions. The nonperturbative computations are based on Monte Carlo simulations with two flavors of clover fermions and utilize the Rome-Southampton method also known as the RI-MOM scheme. We compare the results of this approach with various estimates from lattice perturbation theory, in particular with recent two-loop calculations. (orig.)

  3. Quantum impurities: from mobile Josephson junctions to depletons

    Science.gov (United States)

    Schecter, Michael; Gangardt, Dimitri M.; Kamenev, Alex

    2016-06-01

    We overview the main features of mobile impurities moving in one-dimensional superfluid backgrounds by modeling it as a mobile Josephson junction, which leads naturally to the periodic dispersion of the impurity. The dissipation processes, such as radiative friction and quantum viscosity, are shown to result from the interaction of the collective phase difference with the background phonons. We develop a more realistic depleton model of an impurity-hole bound state that provides a number of exact results interpolating between the semiclassical weakly interacting picture and the strongly interacting Tonks-Girardeau regime. We also discuss the physics of a trapped impurity, relevant to current experiments with ultra cold atoms.

  4. Comparisons of eccentric knee flexor strength and asymmetries across elite, sub-elite and school level cricket players

    Science.gov (United States)

    Chalker, Wade J.; Shield, Anthony J.; Opar, David A.

    2016-01-01

    Background. There has been a continual increase in injury rates in cricket, with hamstring strain injuries (HSIs) being the most prominent. Eccentric knee flexor weakness and bilateral asymmetries are major modifiable risk factors for future HSIs. However, there is a lack of data relating to eccentric hamstring strength in cricket at any skill level. The objective of this study was to compare eccentric knee flexor strength and bilateral asymmetries in elite, sub-elite and school level cricket players; and to determine if playing position and limb role influenced these eccentric knee flexor strength indices. Methods. Seventy four male cricket players of three distinct skill levels performed three repetitions of the Nordic hamstring exercise on the experimental device. Strength was assessed as the absolute and relative mean peak force output for both limbs, with bilateral asymmetries. Differences in mean peak force outputs between skill level and playing positions were measured. Results. There were no significant differences between elite, sub-elite and school level athletes for mean peak force and bilateral asymmetries of the knee flexors. There were no significant differences observed between bowler’s and batter’s mean peak force and bilateral asymmetries. There were no significant differences between front and back limb mean peak force outputs. Discussion. Skill level, playing position and limb role appeared to have no significant effect on eccentric knee flexor strength and bilateral asymmetries. Future research should seek to determine whether eccentric knee flexor strength thresholds are predictive of HSIs in cricket and if specific eccentric knee flexor strengthening can reduce these injuries. PMID:26925310

  5. PEAK AND END RANGE ECCENTRIC EVERTOR/CONCENTRIC INVERTOR MUSCLE STRENGTH RATIOS IN CHRONICALLY UNSTABLE ANKLES: COMPARISON WITH HEALTHY INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Mahmut Komurcu

    2003-09-01

    Full Text Available The aim of this study was to evaluate the alterations in eccentric evertor/concentric invertor strength ratio and their importance in the chronically unstable ankle. Eight patients with chronic ankle instability (CAI and nine healthy individuals participated in this study. Isokinetic concentric and eccentric invertor and evertor muscle strength measurement was carried out at an angular velocity of 120°·sec-1 by measuring maximal force moments (torque during isokinetic ankle inversion and eversion movements. Functionally, evertor/invertor muscle strength ratios (E/I strength ratio were calculated separately based on peak moment and angle-specific moments obtained at 0°, 5°, 10°, 15°, 20° ankle joint angles. Peak and angle-specific eccentric evertor strength values at 0°, 5°, 10°, 15°, 20° were significantly lower in the chronic ankle instability (CAI group. In spite of this, no differences were obtained for peak and angle-specific concentric invertor torque values. Eccentric evertor/concentric invertor strength (Eecc/Icon ratios were also significantly lower in the CAI group, but only at 15° and 20°. Eccentric evertor muscle torque and end range (15°-20° Eecc/Icon strength ratio for the chronically unstable ankle were significantly different from those for the healthy ankle. For this reason, measurements of end range eccentric/concentric strength ratios are more valuable in monitoring chronic ankle injuries and rehabilitation should include not only concentric muscle strengthening but also eccentric muscle strengthening, particularly for the evertor muscles

  6. A comprehensive study on the influence of strength and stiffness eccentricities to the on-plan rotation of asymmetric structure

    Science.gov (United States)

    Rashidi, Azida; Majid, Taksiah A.; Fadzli, M. N.; Faisal, Ade; Noor, Suhaila M.

    2017-10-01

    All buildings are subjected to some degree of torsion which in turn changes the member torsional demands from that of translation only. Torsional effects on buildings subjected to earthquakes are not found directly in structural analysis unless full three-dimensional inelastic dynamic time history analysis is conducted. Since design is often conducted using two-dimensional analysis, these effects are not directly considered. There is currently an understanding on how different factors may influence torsion, however, the degree to which these factors influence torsion is relatively unknown. Slab rotation effect is considered a major response parameter to represent the severity of the torsional response of eccentric systems; hence, it is considered in this study. The centre of strength (CR) and centre of stiffness (CS) are the two main factors under considerations. A comprehensive analysis on eighty different CR and CS conditions are applied to a three-dimensional, asymmetric building and their influences to slab rotation are observed. The CR/CS conditions are applied by varying strength eccentricities (er) and stiffness eccentricities (es) using two condition models. Then, earthquake ground motions are applied in z-direction under elastic and inelastic conditions. The results interpreted using a simple approach shows important slab rotation behaviour that forms interesting findings from this study. The slab rotation demand is found to reduce as strength eccentricity moves away from the Centre of Mass (CoM) but is independent of the stiffness eccentricity. The study also confirms finding of previous works which states that stiffness eccentricity plays a minor role when assessing the torsional behaviour of a ductile systems. Results from inelastic analysis shows slab rotation demand increases as strength eccentricity is closer to the CoM but it remains constant for elastic analysis.

  7. The Beauty of Lattice Perturbation Theory: the Role of Lattice Perturbation Theory in B Physics

    Science.gov (United States)

    Monahan, C. J.

    2012-12-01

    As new experimental data arrive from the LHC the prospect of indirectly detecting new physics through precision tests of the Standard Model grows more exciting. Precise experimental and theoretical inputs are required to test the unitarity of the CKM matrix and to search for new physics effects in rare decays. Lattice QCD calculations of non-perturbative inputs have reached a precision at the level of a few percent; in many cases aided by the use of lattice perturbation theory. This review examines the role of lattice perturbation theory in B physics calculations on the lattice in the context of two questions: how is lattice perturbation theory used in the different heavy quark formalisms implemented by the major lattice collaborations? And what role does lattice perturbation theory play in determinations of non-perturbative contributions to the physical processes at the heart of the search for new physics? Framing and addressing these questions reveals that lattice perturbation theory is a tool with a spectrum of applications in lattice B physics.

  8. Un convoi exceptionnel perturbe la circulation

    CERN Multimedia

    Duraffourd, C

    2004-01-01

    "Le passage d'un convoi exceptionnel hier après-midi dans le secteur de Bellegarde en direction de Cessy aura causé d'importantes perturbations. Entre la deux fois deux voies obturée et les routes secondaires bouclées, les automobilistes ont dû prendre leur mal en patience" (1 page)

  9. Perturbation theory for intermolecular forces including exchange

    NARCIS (Netherlands)

    Lekkerkerker, H.N.W.; Laidlaw, W.G.

    1970-01-01

    Generalized solutions to the Kisenschitz and London perturbation equations are derived. It is pointed out that the results obtained in the formalisms proposed by Hirschfelder (HAV), by Hirschfelder and Silbey, by Murrell and Shaw, and by Musher and Amos are special cases of the generalized

  10. Application of Lie transform perturbation method for ...

    Indian Academy of Sciences (India)

    Three-dimensional non-Hermitian systems are investigated using classical perturbation theory based on Lie transformations. Analytic expressions for total energy in terms of action variables are derived. Both real and complex semiclassical eigenvalues are obtained by quantizing the action variables. It was found that ...

  11. Multiplicative perturbations of local C-semigroups

    Indian Academy of Sciences (India)

    Lipschitz continuous) if S(·) is. Keywords. Local C-semigroup; generator; abstract Cauchy problem; perturbation. 2010 Mathematics Subject Classification. 47D60, 47D62. 1. Introduction. Throughout this paper, we always assume that X is a Banach space with norm. ·, and L(X) denotes the set of all bounded linear operators ...

  12. Perturbations of ultralight vector field dark matter

    CERN Document Server

    Cembranos, J A R; Jareño, S J Núñez

    2016-01-01

    We study the dynamics of cosmological perturbations in models of dark matter based on ultralight coherent vector fields. Very much as for scalar field dark matter, we find two different regimes in the evolution: for modes with $k^2\\ll {\\cal H}ma$, we have a particle-like behaviour indistinguishable from cold dark matter, whereas for modes with $k^2\\gg {\\cal H}ma$, we get a wave-like behaviour in which the sound speed is non-vanishing and of order $c_s^2\\simeq k^2/m^2a^2$. This implies that, also in these models, structure formation could be suppressed on small scales. However, unlike the scalar case, the fact that the background evolution contains a non-vanishing homogeneous vector field implies that, in general, the evolution of the three kinds of perturbations (scalar, vector and tensor) can no longer be decoupled at the linear level. More specifically, in the particle regime, the three types of perturbations are actually decoupled, whereas in the wave regime, the three vector field perturbations generate o...

  13. Geometric singular perturbation theory in biological practice

    NARCIS (Netherlands)

    Hek, G.

    2010-01-01

    Geometric singular perturbation theory is a useful tool in the analysis of problems with a clear separation in time scales. It uses invariant manifolds in phase space in order to understand the global structure of the phase space or to construct orbits with desired properties. This paper explains

  14. Evolution of multimode perturbations in spherical implosions

    Science.gov (United States)

    Flaig, Markus; Thornber, Ben; Flud Group Team

    2017-10-01

    In this project, the growth of perturbations on the inner interface of a dense imploding shell is studied by means of high resolution three-dimensional numerical simulations using the AMR codes PLUTO and FLASH. We consider broadband and narrowband initial perturbations with mode numbers up to l = 200 . Perturbation growth happens as a consequence of Richtmyer-Meshkov instability seeded by the incident shock and subsequent reshocks, as well as Rayleigh-Taylor instability as the interface is decelerated near stagnation. We report on the evolution of the mix layer width, the atomic mix and the turbulent kinetic energy. For the case of broadband initial perturbations, a small-amplitude analysis that is valid beyond reshock is applied to predict the evolution of the mix layer width and to quantify the impact of RT/RM instabilities and convergence and compression effects on the mix layer growth. Finally, it is shown that the mix layer growth is well represented by a just-saturated mode model. This research was supported under the ARC Discovery Projects funding scheme (Project No. DP150101059) and used computational resources at the NCI provided through the NCMAS allocation scheme.

  15. Chiral perturbation theory and nucleon polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Babusci, D.; Giordano, G.; Matone, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy)

    1996-10-01

    The available experimental data concerning the unpolarized cross section for the Compton scattering on the nucleon at low energy are compared with the predictions of the heavy baryon chiral perturbation theory (HBChPT) at the order q{sup 3}.

  16. Perturbation of operators and approximation of spectrum

    Indian Academy of Sciences (India)

    The known results, for a bounded self-adjoint operator, are translated into the case of a norm continuous family of operators. Also an attempt is made to predict the existence of spectral gaps that may occur between the bounds of essential spectrum of A ( 0 ) = A and study the effect of norm continuous perturbation of ...

  17. Application of Lie transform perturbation method for ...

    Indian Academy of Sciences (India)

    Application of Lie transform perturbation method for multidimensional ..... tions of eqs (12) and (13), we can evaluate classical action integrals Ii = ∮ ηi dξi exactly ..... [7] C M Bender, S Boettcher and P N Meisinger, J. Math. Phys. 40, 2201 ...

  18. Gravitino Perturbations in Schwarzschild Black Holes

    Science.gov (United States)

    Fernandez Piedra, Owen Pavel

    We consider the time-evolution of massless gravitino perturbations in Schwarzschild black holes, and show that as in the case of fields of other values of spin, the evolution comes in three stages. After an initial outburst as a first stage, we observe the damped oscillations characteristic of the quasinormal ringing stage, followed by long time tails. Using the sixth-order WKB method and Prony fitting of time domain data we determine the quasinormal frequencies. There is a good correspondence between the results obtained by the above two methods, and we obtain a considerable improvement with respect to the previously obtained third-order WKB results. We also show that the response of a black hole depends crucially on the spin class of the perturbing field: the quality factor becomes a decreasing function of the spin for boson perturbations, whereas the opposite situation appears for fermion ones. With respect to the late-time behavior, we found numerical evidence of a faster decay of gravitino perturbations, a result in constrast with what is known for other neutral fields.

  19. Cell cycle population effects in perturbation studies.

    Science.gov (United States)

    O'Duibhir, Eoghan; Lijnzaad, Philip; Benschop, Joris J; Lenstra, Tineke L; van Leenen, Dik; Groot Koerkamp, Marian J A; Margaritis, Thanasis; Brok, Mariel O; Kemmeren, Patrick; Holstege, Frank C P

    2014-06-21

    Growth condition perturbation or gene function disruption are commonly used strategies to study cellular systems. Although it is widely appreciated that such experiments may involve indirect effects, these frequently remain uncharacterized. Here, analysis of functionally unrelated Saccharyomyces cerevisiae deletion strains reveals a common gene expression signature. One property shared by these strains is slower growth, with increased presence of the signature in more slowly growing strains. The slow growth signature is highly similar to the environmental stress response (ESR), an expression response common to diverse environmental perturbations. Both environmental and genetic perturbations result in growth rate changes. These are accompanied by a change in the distribution of cells over different cell cycle phases. Rather than representing a direct expression response in single cells, both the slow growth signature and ESR mainly reflect a redistribution of cells over different cell cycle phases, primarily characterized by an increase in the G1 population. The findings have implications for any study of perturbation that is accompanied by growth rate changes. Strategies to counter these effects are presented and discussed. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  20. Selection of perturbation experiments for model discrimination

    NARCIS (Netherlands)

    Vatcheva, Ivayla; de Jong, Hidde; Mars, Nicolaas

    2000-01-01

    It often occurs that a system can be described by several competing models. In order to distinguish among the alternative models, further information about the behavior of the system is required. One way to obtain such information is to perform suitably chosen perturbation experiments. We introduce

  1. Perturbations of normally solvable nonlinear operators, I

    Directory of Open Access Journals (Sweden)

    William O. Ray

    1985-01-01

    Full Text Available Let X and Y be Banach spaces and let ℱ and be Gateaux differentiable mappings from X to Y In this note we study when the operator ℱ+ is surjective for sufficiently small perturbations of a surjective operator ℱ The methods extend previous results in the area of normal solvability for nonlinear operators.

  2. Privacy Is Become with, Data Perturbation

    Science.gov (United States)

    Singh, Er. Niranjan; Singhai, Niky

    2011-06-01

    Privacy is becoming an increasingly important issue in many data mining applications that deal with health care, security, finance, behavior and other types of sensitive data. Is particularly becoming important in counterterrorism and homeland security-related applications. We touch upon several techniques of masking the data, namely random distortion, including the uniform and Gaussian noise, applied to the data in order to protect it. These perturbation schemes are equivalent to additive perturbation after the logarithmic Transformation. Due to the large volume of research in deriving private information from the additive noise perturbed data, the security of these perturbation schemes is questionable Many artificial intelligence and statistical methods exist for data analysis interpretation, Identifying and measuring the interestingness of patterns and rules discovered, or to be discovered is essential for the evaluation of the mined knowledge and the KDD process as a whole. While some concrete measurements exist, assessing the interestingness of discovered knowledge is still an important research issue. As the tool for the algorithm implementations we chose the language of choice in industrial world MATLAB.

  3. Renormalized Perturbation Theory A Missing Chapter

    CERN Document Server

    Stora, Raymond

    2008-01-01

    Renormalized perturbation theory à la BPHZ can be founded on causality as analyzed by H. Epstein and V. Glaser in the seventies. Here, we list and discuss a number of additional constraints of algebraic character some of which have to be considered as parts of the core of the BPHZ framework.

  4. Non-perturbative Heavy Quark Effective Theory

    DEFF Research Database (Denmark)

    Della Morte, Michele; Heitger, Jochen; Simma, Hubert

    2015-01-01

    We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays...

  5. Covariant perturbation theory and chiral superpropagators

    CERN Document Server

    Ecker, G

    1972-01-01

    The authors use a covariant formulation of perturbation theory for the non-linear chiral invariant pion model to define chiral superpropagators leading to S-matrix elements which are independent of the choice of the pion field coordinates. The relation to the standard definition of chiral superpropagators is discussed. (11 refs).

  6. Axiomatic approach to perturbative quantum field teory

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, O. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

    1995-10-01

    A derivation with axiomatic methods of a perturbative expansion for the Wightman functions of a relativistic field theory is described. The method gives also the correlation functions of the fields in KMS states. Using these results, a scattering formalism for QED is introduced, which does not involve any infrared divergent quantities. (orig.).

  7. High-precision extreme-mass-ratio inspirals in black hole perturbation theory and post-Newtonian theory

    Science.gov (United States)

    Forseth, Erik Robert

    The recent detection of gravitational wave (GW) signal GW150914 by the Advanced LIGO experiment has inaugurated the long-anticipated era of GW astronomy. This event saw the merger of two black holes, having roughly 36 and 29 solar masses, as well as the ringdown of the resulting 62 solar mass black hole. The energy emitted in gravitational radiation was equivalent to about three solar masses. The detection underscored the importance of theoretical models for not only isolating signal from noise, but especially for the accurate estimation of source parameters. The two-body problem in Einstein's general theory has no exact solution, and so the development of these models is highly nontrivial. We present in this thesis a set of original results on the dynamics of the inspiral for a class of binary systems known as extreme-mass-ratio inspirals (EMRIs), comprised of a small compact object (generically a stellar mass black hole) in orbit about a supermassive black hole. Our work also has potential application to intermediate-mass-ratio inspirals (IMRIs). IMRIs are thought to be a potentially strong source for ground-based GW experiments such as Advanced LIGO/VIRGO. Though not generally a good source for the LIGO network, EMRIs on the other hand are well-suited for detection by proposed space-based detectors, e.g. eLISA. Our work particularly constitutes a program of developing computational tools, methods, and results for eccentric E/IMRIs, which are thought to be astrophysically important but are much more challenging to model theoretically compared with circular orbits. We begin with a brief review of relevant parts of general relativity (GR) theory, followed by overviews of two prevailing approximation formalisms in GR, black hole perturbation (BHP) theory and post-Newtonian (PN) theory. Our first original result is a high-precision computation of the first-order gravitational metric perturbation using a Lorenz gauge frequency domain procedure. Next, we present a fast

  8. Perturbative and non-perturbative aspects of heavy-quark fragmentation

    CERN Document Server

    Gardi, E; Gardi, Einan; Cacciari, Matteo

    2004-01-01

    We describe a new approach to heavy-quark fragmentation which is based on a resummed perturbative calculation and parametrization of power corrections, concentrating on the z -> 1 limit, where the heavy meson carries a large fraction of the momentum of the initial quark. It is shown that the leading power corrections in this region are controlled by the scale m(1-z). Renormalon analysis is then used to extend the perturbative treatment of soft and collinear radiation to the non-perturbative regime. Theoretical predictions are confronted with data on B-meson production in e+e- annihilation.

  9. Unique Fock quantization of scalar cosmological perturbations

    Science.gov (United States)

    Fernández-Méndez, Mikel; Mena Marugán, Guillermo A.; Olmedo, Javier; Velhinho, José M.

    2012-05-01

    We investigate the ambiguities in the Fock quantization of the scalar perturbations of a Friedmann-Lemaître-Robertson-Walker model with a massive scalar field as matter content. We consider the case of compact spatial sections (thus avoiding infrared divergences), with the topology of a three-sphere. After expanding the perturbations in series of eigenfunctions of the Laplace-Beltrami operator, the Hamiltonian of the system is written up to quadratic order in them. We fix the gauge of the local degrees of freedom in two different ways, reaching in both cases the same qualitative results. A canonical transformation, which includes the scaling of the matter-field perturbations by the scale factor of the geometry, is performed in order to arrive at a convenient formulation of the system. We then study the quantization of these perturbations in the classical background determined by the homogeneous variables. Based on previous work, we introduce a Fock representation for the perturbations in which: (a) the complex structure is invariant under the isometries of the spatial sections and (b) the field dynamics is implemented as a unitary operator. These two properties select not only a unique unitary equivalence class of representations, but also a preferred field description, picking up a canonical pair of field variables among all those that can be obtained by means of a time-dependent scaling of the matter field (completed into a linear canonical transformation). Finally, we present an equivalent quantization constructed in terms of gauge-invariant quantities. We prove that this quantization can be attained by a mode-by-mode time-dependent linear canonical transformation which admits a unitary implementation, so that it is also uniquely determined.

  10. Growth of matter perturbation in quintessence cosmology

    Science.gov (United States)

    Mulki, Fargiza A. M.; Wulandari, Hesti R. T.

    2017-01-01

    Big bang theory states that universe emerged from singularity with very high temperature and density, then expands homogeneously and isotropically. This theory gives rise standard cosmological principle which declares that universe is homogeneous and isotropic on large scales. However, universe is not perfectly homogeneous and isotropic on small scales. There exist structures starting from clusters, galaxies even to stars and planetary system scales. Cosmological perturbation theory is a fundamental theory that explains the origin of structures. According to this theory, the structures can be regarded as small perturbations in the early universe, which evolves as the universe expands. In addition to the problem of inhomogeneities of the universe, observations of supernovae Ia suggest that our universe is being accelerated. Various models of dark energy have been proposed to explain cosmic acceleration, one of them is cosmological constant. Because of several problems arise from cosmological constant, the alternative models have been proposed, one of these models is quintessence. We reconstruct growth of structure model following quintessence scenario at several epochs of the universe, which is specified by the effective equation of state parameters for each stage. Discussion begins with the dynamics of quintessence, in which exponential potential is analytically derived, which leads to various conditions of the universe. We then focus on scaling and quintessence dominated solutions. Subsequently, we review the basics of cosmological perturbation theory and derive formulas to investigate how matter perturbation evolves with time in subhorizon scales which leads to structure formation, and also analyze the influence of quintessence to the structure formation. From analytical exploration, we obtain the growth rate of matter perturbation and the existence of quintessence as a dark energy that slows down the growth of structure formation of the universe.

  11. Perturbation theory for cosmologies with nonlinear structure

    Science.gov (United States)

    Goldberg, Sophia R.; Gallagher, Christopher S.; Clifton, Timothy

    2017-11-01

    The next generation of cosmological surveys will operate over unprecedented scales, and will therefore provide exciting new opportunities for testing general relativity. The standard method for modelling the structures that these surveys will observe is to use cosmological perturbation theory for linear structures on horizon-sized scales, and Newtonian gravity for nonlinear structures on much smaller scales. We propose a two-parameter formalism that generalizes this approach, thereby allowing interactions between large and small scales to be studied in a self-consistent and well-defined way. This uses both post-Newtonian gravity and cosmological perturbation theory, and can be used to model realistic cosmological scenarios including matter, radiation and a cosmological constant. We find that the resulting field equations can be written as a hierarchical set of perturbation equations. At leading-order, these equations allow us to recover a standard set of Friedmann equations, as well as a Newton-Poisson equation for the inhomogeneous part of the Newtonian energy density in an expanding background. For the perturbations in the large-scale cosmology, however, we find that the field equations are sourced by both nonlinear and mode-mixing terms, due to the existence of small-scale structures. These extra terms should be expected to give rise to new gravitational effects, through the mixing of gravitational modes on small and large scales—effects that are beyond the scope of standard linear cosmological perturbation theory. We expect our formalism to be useful for accurately modeling gravitational physics in universes that contain nonlinear structures, and for investigating the effects of nonlinear gravity in the era of ultra-large-scale surveys.

  12. Reliability of concentric and eccentric strength of hip abductor and adductor muscles in young soccer players

    Directory of Open Access Journals (Sweden)

    V Gerodimos

    2016-01-01

    Full Text Available The concentric and eccentric strength profile and muscular balance of the hip joint are important parameters for success in soccer. This study evaluated the reliability for the assessment of hip abduction and adduction isokinetic strength over a range of angular velocities (30 and 90°/s and types of muscular actions (concentric and eccentric in young soccer players. The reliability for the assessment of reciprocal (conventional and functional and bilateral torque ratios was also examined. Fifteen male soccer players (15±1 years performed two sessions, separated by three days. The testing protocol consisted of five maximal concentric and eccentric hip abductions and adductions of both legs at angular velocities of 30°/s and 90°/s. The peak torque was evaluated in young soccer players using an isokinetic dynamometer (Cybex Norm, and the reciprocal strength ratios (conventional and functional and bilateral ratios (non-preferred to preferred leg ratios were calculated. The test-retest reliability for the assessment of peak torque (lCC=0.71-0.92 and of reciprocal muscle group ratios (lCC=0.44-0.87 was found to be moderate to high. Bilateral torque ratios exhibited low to moderate reliability (|CC=0.11-0.64. In conclusion, isokinetic strength of hip abductor and adductor muscles and the conventional and functional strength ratios can be reliably assessed in young soccer players, especially at low angular velocities. The assessment, however, of bilateral strength ratios for hip abductor/adductor muscles should be interpreted with more caution.

  13. THE COMBINATION OF α-LIPOIC ACID INTAKE WITH ECCENTRIC EXERCISE MODULATES ERYTHROPOIETIN RELEASE

    Directory of Open Access Journals (Sweden)

    B. Morawin

    2014-08-01

    Full Text Available The generation of reactive nitrogen/oxygen species (RN/OS represents an important mechanism in erythropoietin (EPO expression and skeletal muscle adaptation to physical and metabolic stress. RN/OS generation can be modulated by intense exercise and nutrition supplements such as α-lipoic acid, which demonstrates both anti- and pro-oxidative action. The study was designed to show the changes in the haematological response through the combination of α-lipoic acid intake with running eccentric exercise. Sixteen healthy young males participated in the randomised and placebo-controlled study. The exercise trial involved a 90-min run followed by a 15-min eccentric phase at 65% VO2max (-10% gradient. It significantly increased serum concentrations of nitric oxide (NO, hydrogen peroxide (H2O2 and pro-oxidative products such as 8-isoprostanes (8-iso, lipid peroxides (LPO and protein carbonyls (PC. α-Lipoic acid intake (Thiogamma: 1200 mg daily for 10 days prior to exercise resulted in a 2-fold elevation of serum H2O2 concentration before exercise, but it prevented the generation of NO, 8-iso, LPO and PC at 20 min, 24 h, and 48 h after exercise. α-Lipoic acid also elevated serum EPO level, which highly correlated with NO/H2O2 ratio (r=0.718, P<0.01. Serum total creatine kinase (CK activity, as a marker of muscle damage, reached a peak at 24 h after exercise (placebo 732 ± 207 IU · L-1, α-lipoic acid 481 ± 103 IU · L-1, and correlated with EPO (r = 0.478, P<0.01 in the α-lipoic acid group. In conclusion, the intake of high α-lipoic acid modulates RN/OS generation, enhances EPO release and reduces muscle damage after running eccentric exercise.

  14. Direct N-body simulations of globular clusters - III. Palomar 4 on an eccentric orbit

    Science.gov (United States)

    Zonoozi, Akram Hasani; Haghi, Hosein; Kroupa, Pavel; Küpper, Andreas H. W.; Baumgardt, Holger

    2017-05-01

    Palomar 4 (Pal 4) is a low-density globular cluster (GC) with a current mass ≈30 000 M⊙ in the outer halo of the Milky Way with a two-body relaxation time of the order of a Hubble time. Yet, it is strongly mass segregated and contains a stellar mass function depleted of low-mass stars. Pal 4 was either born this way or it is a result of extraordinary dynamical evolution. Since two-body relaxation cannot explain these signatures alone, enhanced mass-loss through tidal shocking may have had a strong influence on Pal 4. Here, we compute a grid of direct N-body simulations to model Pal 4 on various eccentric orbits within the Milky Way potential to find likely initial conditions that reproduce its observed mass, half-light radius, stellar slope of the mass function and line-of-sight velocity dispersion. We find that Pal 4 is most likely orbiting on an eccentric orbit with an eccentricity of e ≈ 0.9 and pericentric distance of Rp ≈ 5 kpc. In this scenario, the required 3D half-mass radius at birth is similar to the average sizes of typical GCs (Rh ≈ 4-5 pc), while its birth mass is about M0 ≈ 105 M⊙. We also find a high degree of primordial mass segregation among the cluster stars, which seems to be necessary in every scenario we considered. Thus, using the tidal effect to constrain the perigalactic distance of the orbit of Pal 4, we predict that the proper motion of Pal 4 should be in the range -0.52 ≤ μδ ≤ -0.38 mas yr-1 and -0.30 ≤ μαcos δ ≤ - 0.15 mas yr-1.

  15. Assessment of Muscle Pain Induced by Elbow-Flexor Eccentric Exercise.

    Science.gov (United States)

    Lau, Wing Yin; Blazevich, Anthony J; Newton, Michael J; Wu, Sam Shi Xuan; Nosaka, Kazunori

    2015-11-01

    Delayed-onset muscle soreness (DOMS) is a common muscle pain that many people experience and is often used as a model of acute muscle pain. Researchers have reported the effects of various interventions on DOMS, but different DOMS assessment protocols used in these studies make it difficult to compare the effects. To investigate DOMS characteristics after elbow-flexor eccentric exercise to establish a standardized DOMS assessment protocol. Descriptive laboratory study. Research laboratory. Ten healthy, untrained men (21-39 years). Participants performed 10 sets of 6 maximal isokinetic eccentric contractions of the elbow flexors. Indirect muscle-damage markers were maximal voluntary isometric contraction torque, range of motion, and serum creatine kinase activity. Muscle pain was assessed before exercise, immediately postexercise, and 1 to 5 days postexercise using (1) a visual analog scale (VAS), (2) a category ratio-10 scale (CR-10) when applying static pressure and palpation at different sites (3, 9, and 15 cm above the elbow crease), and (3) pressure-pain thresholds (PPTs) at 50 sites (pain mapping). Maximal voluntary isometric contraction and range of motion decreased and creatine kinase activity increased postexercise, indicating muscle damage. Palpation induced greater pain than static pressure, and longitudinal and transverse palpations induced greater pain than circular palpation (P muscles are assessed affects the pain level score. This finding suggests that pain level and pain threshold cannot be used interchangeably and that the central and distal regions of the biceps brachii should be included in DOMS assessment using the VAS, CR-10 scale, and PPT after elbow-flexor eccentric exercise.

  16. Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individuals

    Directory of Open Access Journals (Sweden)

    Cribb Paul J

    2009-06-01

    Full Text Available Abstract Background Eccentric exercise-induced damage leads to reductions in muscle force, increased soreness, and impaired muscle function. Creatine monohydrate's (Cr ergogenic potential is well established; however few studies have directly examined the effects of Cr supplementation on recovery after damage. We examined the effects of Cr supplementation on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. Methods Fourteen untrained male participants (22.1 ± 2.3 yrs, 173 ± 7.7 cm, 76.2 ± 9.3 kg were randomly separated into 2 supplement groups: i Cr and carbohydrate (Cr-CHO; n = 7; or ii carbohydrate (CHO; n = 7. Participants consumed their supplement for a period of 5 days prior to, and 14 days following a resistance exercise session. Participants performed 4 sets of 10 eccentric-only repetitions at 120% of their maximum concentric 1-RM on the leg press, leg extension and leg flexion exercise machine. Plasma creatine kinase (CK and lactate dehydrogenase (LDH activity were assessed as relevant blood markers of muscle damage. Muscle strength was examined by voluntary isokinetic knee extension using a Cybex dynamometer. Data were analyzed using repeated measures ANOVA with an alpha of 0.05. Results The Cr-supplemented group had significantly greater isokinetic (10% higher and isometric (21% higher knee extension strength during recovery from exercise-induced muscle damage. Furthermore, plasma CK activity was significantly lower (by an average of 84% after 48 hrs (P Conclusion The major finding of this investigation was a significant improvement in the rate of recovery of knee extensor muscle function after Cr supplementation following injury.

  17. Uncoupling of in vivo torque production from EMG in mouse muscles injured by eccentric contractions

    Science.gov (United States)

    Warren, Gordon L; Ingalls, Christopher P; Shah, Shree J; Armstrong, R B

    1999-01-01

    The main objective of this study was to determine whether eccentric contraction-induced muscle injury causes impaired plasmalemmal action potential conduction, which could explain the injury-induced excitation-contraction coupling failure. Mice were chronically implanted with stimulating electrodes on the left common peroneal nerve and with electromyographic (EMG) electrodes on the left tibialis anterior (TA) muscle. The left anterior crural muscles of anaesthetized mice were stimulated to perform 150 eccentric (ECC) (n = 12 mice) or 150 concentric (CON) (n = 11 mice) contractions. Isometric torque, EMG root mean square (RMS) and M-wave mean and median frequencies were measured before, immediately after, and at 1, 3, 5 and 14 days after the protocols. In parallel experiments, nicotinic acetylcholine receptor (AChR) concentration was measured in TA muscles to determine whether the excitation failure elicited a denervation-like response.Immediately after the ECC protocol, torque was reduced by 47–89%, while RMS was reduced by 9–21%; the RMS decrement was not different from that observed for the CON protocol, which did not elicit large torque deficits. One day later, both ECC and CON RMS had returned to baseline values and did not change over the next 2 weeks. However, torque production by the ECC group showed a slow recovery over that time and was still depressed by 12–30% after 2 weeks. M-wave mean and median frequencies were not affected by performance of either protocol.AChR concentration was elevated by 79 and 368% at 3 and 5 days, respectively, after the ECC protocol; AChR concentration had returned to control levels 2 weeks after the protocol. At the time of peak AChR concentration in the ECC protocol muscles (i.e. 5 days), AChR concentration in CON protocol muscles was not different from the control level.In conclusion, these data demonstrate no major role for impaired plasmalemmal action potential conduction in the excitation-contraction coupling

  18. Studying laminar flows of power-law fluids in the annular channel with eccentricity

    Science.gov (United States)

    Zhigarev, V. A.; Neverov, A. L.; Guzei, D. V.; Pryazhnikov, M. I.

    2017-09-01

    The paper deals with numerical and experimental investigation of non-Newtonian flow of modeling drilling fluids in the annular channel. The Reynolds number was ranged from 100 to 1500. The parameters of the power-law model of drilling fluids were varied within the following ranges: n = 0.43-0.49, K = 0.22-0.89. The eccentricity was changed from 0 to 1. We have measured pressure drop in the annular channel and compared calculations with experimental data, achieving good agreement between calculations and experiment.

  19. Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis

    DEFF Research Database (Denmark)

    Langberg, Henning; Ellingsgaard, H; Madsen, T

    2007-01-01

    in the initially injured tendon (n=6; carboxyterminal propeptide of type I collagen (PICP): pre 3.9+/-2.5 microg/L to post 19.7+/-5.4 microg/L, P0.05). Collagen degradation, measured as carboxyterminal telopeptide region of type I collagen (ICTP), was not affected by training neither in the injured nor...... in the healthy tendons. The clinical effect of the 12 weeks of eccentric training was determined by using a standardized loading procedure of the Achilles tendons showing a decrease in pain in all the chronic injured tendons (VAS before 44+/-9, after 13+/-9; P...

  20. Eccentric and concentric muscle performance following 7 days of simulated weightlessness

    Science.gov (United States)

    Hayes, Judith C.; Roper, Mary L.; Mazzocca, Augustus D.; Mcbrine, John J.; Barrows, Linda H.; Harris, Bernard A.; Siconolfi, Steven F.

    1992-01-01

    Changes in skeletal muscle strength occur in response to chronic disuse or insufficient functional loading. The purpose of this study was to examine changes in muscle performance of the lower extremity and torso prior to and immediately after 7 days of simulated weightlessness (horizontal bed rest). A Biodex was used to determine concentric and eccentric peak torque and angle at peak torque for the back, abdomen, quadriceps, hamstring, soleus, and tibialis anterior. A reference angle of 0 degrees was set at full extension. Data were analyzed by ANOVA.